**Beyond protocols: improving the reliability of expert-based risk analysis underpinning invasive species policies**

Sonia Vanderhoeven<fnref n="1" />, Etienne Branquart<fnref n="6" />, Bram D'hondt<fnref n="5" />, Phil Hulme<fnref n="9" />, Assaf Schwartz<fnref n="3" />, Diederik Strubbe<fnref n="4" />, Anne Turbé<fnref n="7" />, Niall Moore<fnref n="8" />, Jim Casaer<fnref n="2" />, Hugo Verreycken<fnref n="2" />, Tim Adriaens<fnref n="2" />

Risk assessment tools for invasive alien species need to incorporate all evidence and expertise available. Despite the wealth of protocols now available to this end, we believe the current way of performing risk assessments shows several shortcomings and provide examples with regards to the newly implemented EU IAS Regulation. In particular, baseline data on ecological impacts, transparency in the decision making, uncertainty and content control should be properly considered for decision making. We recommend improved quality control through formalized peer review with clear feedback to authors and reviewers, and stress the importance of ensuring repeatability and transparency. Alternatively, to better capture opinions of different experts, thereby maximizing the evidential basis, a consensus approach can be applied which also provides inter-rater reliability. Manageability should also be explicitly covered in risk analysis. Tackling the invasive species issue requires better handling of the acquired information on risk and the exploration of novel methodologies for decision making on biodiversity management. Quality assurance, repeatability, clear procedures and transparent decision making are crucial for efficient conservation resource allocation and uptake by stakeholders and the public.

Keywords: evidence-based conservation, expert judgement, decision making, manageability, listing

<footnote n="1">¹Belgian Biodiversity Platform, Gembloux, Belgium</footnote>

<footnote n="2">²Research Institute for Nature and Forest (INBO), Brussels, Belgium</footnote>

<footnote n="3">³Faculty of Architecture and Town Planning Technion, Haifa, Israel</footnote>

<footnote n="4">⁴Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium</footnote>

<footnote n="5">⁵Biology Department, Ghent University, Gent, Belgium</footnote>

<footnote n="6">⁶Invasive Species Unit, Département de l'Etude du Milieu Naturel et Agricole (DEMNA), Gembloux, Belgium</footnote>

<footnote n="7">⁷BIO Intelligence Service, Neuilly-sur-Seine, France</footnote>

<footnote n="8">⁸Animal and Plant Health Agency (APHA), York, United Kingdom</footnote>

<footnote n="9">⁹The Bio-Protection Research Centre, Lincoln University, Canterbury, New Zealand</footnote>
# Prioritising surveillance for alien organisms transported as stowaways on ships

Katelyn Faulkner¹, ², Mark Robertson², Mathieu Rouget³, John Wilson¹, ⁴

¹Invasive Species Programme, South African National Biodiversity Institute, Cape Town, South Africa

²Centre for Invasion Biology, Department of Zoology and Entomology, University of Pretoria,
Pretoria, South Africa

³Centre for Invasion Biology, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa

⁴Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University,
Stellenbosch, South Africa

As many alien and invasive species have been introduced to South Africa as stowaways, the vectors of these organisms need to be further managed. One such vector is global shipping which facilitates the transportation and introduction of both marine and terrestrial stowaway organisms. Ship movement data and seasonal environment matches were used to evaluate how the marine and terrestrial invasion risk posed by shipping to South Africa varies across shipping routes and seasons. Species distribution data were used to identify species that are known to be invasive elsewhere, and which might be introduced to South Africa through the shipping routes that pose a high relative invasion risk. Shipping routes from Asian ports, especially Singapore, pose a particularly high relative invasion risk to South Africa. Of the South African ports, Durban has the highest risk of being invaded. The relative invasion risk posed by the shipping routes to South African ports varied little across the seasons, but the relative importance of the routes changes seasonally. Our results indicate that port- and season-specific prevention strategies should be developed, and a large portion of the available resources should be allocated to Durban. The presented method provides a simple way to prioritise surveillance effort between ports of entry, shipping routes, and seasons.

Keywords: biological invasions, biosecurity, prevention strategies, marine environment, terrestrial environment, resource allocation
# Detection of invasive gobies by probing freshwater samples for DNA traces

Irene Adrian-Kalchhauser<fnref n="1" />, Patricia Burkhardt-Holm<fnref n="1" />, <fnref n="2" />

Ponto-Caspian gobies are a flock of five invasive fish species that have colonized freshwaters and brackish waters in Europe and North America. One of them, the round goby *Neogobius melanostomus*, figures among the 100 worst invaders in Europe. Current methods to detect the species involve catching or sighting the fish. These approaches are labor intense and not very sensitive. Consequently, populations are usually detected only when they have reached high densities and when management or containment efforts are futile. eDNA (environmental DNA) assays detect the presence of a species from the genetic traces it leaves behind in its environment. Typically, such assays require less time and less manpower and thus less financial resources than conventional monitoring methods, and are less invasive for the ecosystem. Therefore, we developed an assay to specifically detect DNA traces of Ponto-Caspian gobies in river water. We will present how sampling and experimental parameters greatly impact detection and will explain why eDNA assays by their nature can provide qualitative but not quantitative results. We will show how we successfully applied the assay to outline the invasion front of Ponto-Caspian gobies in a large river, the High Rhine in Switzerland. In summary, we introduce a functional assay that enables environment managers to quickly and cheaply map areas invaded by Ponto-Caspian gobies, independently of fishermen's reports and of fish community monitorings.

Keywords: eDNA, detection, monitoring

<footnote n="1">¹University of Basel, Basel, Switzerland</footnote>

<footnote n="2">²University of Alberta, Edmonton, Canada</footnote>
# Parsing Propagule Pressure: The effects of multiple aspects of propagule pressure on the success of the invasive musk thistle *Carduus nutans*

Katriona Shea<fnref n="1" />, Ciara Hovis<fnref n="1" />, Joseph Keller<fnref n="1" />, Brittany Teller<fnref n="2" />, Ruth Hufbauer<fnref n="3" />

Propagule pressure explains the success of many biological invaders. It is typically thought of as composite measure of the number of non-native individuals released (intensity) at discrete events and the number of release events (frequency). However, additional aspects of propagule pressure may also play a role. Using a theoretical framework from disturbance, and thinking of propagule pressure as a perturbation of the existing community, suggests that timing and duration of propagule arrival may also affect invasion outcomes.

We demonstrate the utility of this framework in a study of the successful invasion of musk thistle (*Carduus nutans*) in the USA. We examined both intensity and frequency in conjunction with invasion timing, duration, and genetic diversity to determine their effects on local establishment of musk thistle in a large, multi-year field experiment. We also evaluated effects on survival, probability of reproduction and fecundity.

As expected, invasion success increased with intensity. However, the frequency of release events was not as important as their distribution in time. Contrary to expectations, genetic diversity had no significant impact on invasion outcomes in this study. Our results suggest that seasonal timing of propagule arrival may have a greater effect on establishment than previously realized. Furthermore, only considering one or two aspects of propagule pressure may provide a misleading view of the factors affecting invasion. Understanding the relative importance of multiple, interacting aspects of propagule pressure will be key to improved predictive ability for invasive species, and will also likely help to prevent future invasions.

Keywords: invasion, disturbance, propagule

<footnote n="1">¹The Pennsylvania State University, University Park, United States</footnote>

<footnote n="2">²Utah State University, Logan, United States</footnote>

<footnote n="3">³Colorado State University, Fort Collins, United States</footnote>
Poster presentations
**Topic 01**
**Biological invasions and climate change**

P-01

**Will Climate Change Impact Distribution of Common Ragweed in Turkey?**

Shahid Farooq<fnref n="1" />, Huseyin Onen<fnref n="1" />, Hakan Yildiz<fnref n="2" />, Hikmet Gunal<fnref n="3" />, Cumali Ozaslan<fnref n="4" />

Common ragweed (Ambrosia artemisiifolia L.) is noxious invader causing severe pollen allergies. Ragweed has extended its range over a considerable portion of the Turkey after its first record in 1998. Ragweed infestation in agricultural areas (particularly in sunflower fields) has recently been reported. The plant has become a detrimental threat to agriculture and human health in the country. Climate change will affect the distribution of ragweed and complicate the management of plant. Although Turkey is among the countries which are vulnerable to the expected climate changes, this is the first report to assess the impacts of climate change on potential distribution of ragweed in Turkey. In the current study, a process-oriented niche model was developed using CLIMEX software to map the potential distribution of ragweed in Turkey under different climate change scenarios. The data on the current distribution of plant was recorded through extensive surveys in the country. We used two climate change scenarios A₁B and A₂ and climate data from two different sources CSIRO and MIROC-H. The model was run for current climatic conditions of 2030, 2050 and 2100. The results indicated that more than half of the country is vulnerable to ragweed invasion under current climate while, further spread was expected under climate change scenarios. The potential distribution area was increased in 2030 and 2050 while decline was observed in 2100. Expected warming is possible reason of range contraction in 2100. Ragweed can present severe agricultural and health concerns under changing climate up to 2050. The areas to North West of the country, which are densely populated, are more prone to invasion.

(This study was funded by TUBITAK with grant number 113 O 790 as a part of Cost Action TD-1209. The results also address the major challenges focused by Cost Action FA-1203)

Keywords: Common ragweed, potential distribution, climate change, Turkey

<footnote n="1">¹Department of Plant Protection, Faculty of Agriculture, Gaziosmanpasa University, Tokat, Turkey</footnote>

<footnote n="2">²Field Crops Central Research Institute, Ankara, Turkey</footnote>

<footnote n="3">³Department of Soil Science and Plant Nutrition, Faculty of Agriculture, Gaziosmanpasa University, Tokat, Turkey</footnote>

<footnote n="4">⁴Department of Plant Protection, Faculty of Agriculture, Dicle University, Diyarbakır, Turkey</footnote>
# Diversity of the genus *Symphyotrichum* and trends of contemporary spread of its species in Lithuania

Zigmantas Gudžinskas<fnref n="1" />, Lukas Petrulaitis<fnref n="1" />,<fnref n="2" />

The genus *Symphyotrichum* (Asteraceae) is native to North America and includes more than 90 species. In Europe, this genus is represented by 16 alien species. Taxonomy of the genus is extremely difficult, because European populations include plants that are products of artificial breeding in cultivation and spontaneous hybridization following escape. Two species of this genus, *Symphyotrichum novi-belgii* and *S. lanceolatum*, are mentioned in the list of 150 most widespread alien plant species in Europe, which occur in more than 25 regions. Several other species are already invasive locally or in certain European countries.

The analysis of plants collected during field investigations in 2013–2015 and the study of herbarium specimens revealed that in Lithuania the genus *Symphyotrichum* is represented by seven species: *S. dumosum*, *S. novae-angliae*, *S. pilosum*, *S. ×salignum*, *S. lanceolatum*, *S. novi-belgii* and *S. ×versicolor*.

Two species, *S. lanceolatum* and *S. ×salignum*, are the most widespread species of this genus. The first species is most frequent and abundant in North Lithuania, where it occupies habitats of river valleys and lake shores. *S. ×salignum* is mainly distributed in East Lithuania. Both species produce viable seeds. *S. novi-belgii* is somewhat rarer, though is distributed throughout Lithuania. This species as well as rather rare *S. novae-angliae* and *S. ×versicolor* occupy mainly anthropogenic habitats. Localities of *S. dumosum* are concentrated in East Lithuania. Generative reproduction of this very late flowering species has not been recorded yet. *S. pilosum* is very rare, recorded in two localities along the River Širvinta in Central Lithuania. It also occupies riparian habitats, produces viable seeds and further spread is expected. Particular geographical distribution of certain *Symphyotrichum* species is probably mainly determined by history of cultivation and less by natural conditions.

Late flowering plants of the genus *Symphyotrichum* in Lithuania and the Baltic Region were considered as non-invasive, because they produced seeds only occasionally. However, because of climate change during the last decades and, therefore, warm and much extended autumns, which sometimes continues till the end of November, generative reproduction has become more intense. These factors facilitate spread of several *Symphyotrichum* species. They invade almost all riparian habitats, various types of meadows and anthropogenic habitats. At least three species, *S. lanceolatum*, *S. novi-belgii* and *S. ×salignum*, are potentially invasive in Lithuania.

Keywords: Climate change, distribution, generative reproduction, habitats, invasion, spread.

<footnote n="1">¹Nature Research Centre, Institute of Botany, Vilnius, Lithuania</footnote>

<footnote n="2">²Vilnius University, Faculty of Natural Sciences, Vilnius, Lithuania</footnote>
**Climate warming accelerates the life cycle of the invasive musk thistle (Carduus nutans)**

Joseph Keller, Katriona Shea

Department of Biology, The Pennsylvania State University, University Park, United States

Climate change has the potential to alter the life cycles of many plants. Warmer temperatures can advance mother plants' phenology, causing earlier seed release and earlier germination of fall-germinating seeds. Warming can also extend the growing season later into the fall. Together these effects may increase the sizes to which seedlings grow in their first season. The demography of monocarpic perennials with size-dependent flowering may be particularly sensitive to these changes, as increased growth causes individuals to reach size thresholds for reproduction more quickly.

We investigated the effects of earlier seed release and warming on the life cycle of musk thistle (Carduus nutans) in a two-cohort field experiment with seven planting time treatments (ranging from planting in early August to planting in mid-November) and two temperature treatments (warmed in fiberglass open-top chambers and ambient).

Earlier planting resulted in larger rosette sizes at the end of the first growing season, which lead to a larger fraction of individuals flowering as annuals. Warming also increased the growth of rosettes. We modelled the impact of these changes on population growth rates using integral projection models. Together, increased growth and larger size of new rosettes are projected to dramatically increase the local population growth rate, indicating the potential for this invasive weed to become more problematic as warming progresses. These changes may also open new opportunities for improved management, for example via targeted mowing of flowering individuals.

Keywords: Climate warming, phenology, integral projection model, thistle, Carduus nutans
**Will climate change increase range overlap between potential invaders and their native congeners in Europe?**

Günther Klonner<fnref n="1" />, Stefan Dullinger<fnref n="1" />, Iwona Dullinger<fnref n="1" />, Franz Essl<fnref n="1" />, Johannes Wessely<fnref n="1" />, Marten Winter<fnref n="2" />, et al.

What determines whether a species becomes invasive or not is one of the central questions of invasion biology. Among the many factors involved, interspecific hybridization with native congeners, or with naturalized other closely related aliens, has recently been shown to clearly promote invasiveness, at least in plants. Such hybridizations of course require that the geographical distribution of species with their wild congeners actually overlap. With climate change, ranges of species are expected to change, and these changes might bring species in contact that have previously been isolated, or at least increase the overlap of their ranges and hence the hybridization risk.

In this paper we use species distribution models to predict how the overlap of climatically suitable ranges of a set of potential future invaders and their already present congeners will actually change under three scenarios of climate warming in Europe. Potential invaders were defined as ornamental species that are already cultivated in Europe and have naturalized in some alien ranges outside Europe, but not in Europe itself so far. From this pool of species we selected those genera where evidence for hybridization during invasions has already been provided in the literature and for which either native or alien congeners exist in Europe. We used the “area under the curve” and “Cohen’s kappa” as measures of overlap between the climatically suitable ranges of species. We hypothesized an overall increase in range overlap and hence in hybridization risk.

Our results did, however, not confirm our expectations. On average, the climatically suitable range of potential invaders in Europe increases, but the one of native congeners decreases. As a net balance, the amount of range overlap remains approximately constant. However, there is pronounced variation among genera and for some of them the increase in range overlap is actually considerable. As a consequence, while hybridization risk among invaders and their congeners does not generally rise, there are nevertheless individual cases where at least the contact between potential hybridization partners may strongly increase.

Keywords: biological invasions, climate change, hybridization risk, interspecific
hybridization, potential future invaders, range overlap, species distribution models

<footnote n="1">¹University of Vienna Faculty of Life Sciences Department of Botany and Biodiversity Research
Division of Conservation Biology, Vegetation and Landscape Ecology, Vienna, Austria</footnote>

<footnote n="2">²German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany</footnote>
**Response of *Torymus sinensis* (Hymenoptera: Torymidae), a parasitoid of the invasive pest *Dryocosmus kuriphilus*, to olfactory and visual cues**

Éva Kriston<fnref n="1" />, László Krizbai<fnref n="1" />, Miklós Bozsó<fnref n="1" />, Dinka Matošević<fnref n="2" />, George Melika<fnref n="1" />

*Torymus sinensis* Kamijo (Hymenoptera, Torymidae) is a biological control agent of the chestnut gall wasp, *Dryocosmus kuriphilus* Yasumatsu (Hymenoptera, Cynipidae), that has been successfully used in classical biological control programs in Japan (1975), the USA (in the late 1970s), Italy (2005), France (2011), Hungary and Croatia (2014-2015), Slovenia (2015). It is a univoltine species like its host. After early spring emergence and mating, the female lays eggs inside the larval chamber of newly formed galls, usually one egg per host larva. After hatching the larva feeds ectoparasitically on the host larva, and it pupates in the host larval chamber during winter.

The introduction of this parasitoid is widely known as one of the typical successful cases of classical biological control; however, the risks of the agent concerning potential negative effects on nontarget native oak gall inducers have never been evaluated thoroughly.

Relatively little is known about its host location and host acceptance behavior that was investigated by using a Y-tube olfactometer. Six days old, matted and unmated females were tested for their response to olfactory and visual cues associated with *D. kuriphilus* galls versus cynipid oak galls (*Biorhiza pallida* and *Andricus curvator*) and chestnut foliage versus oak foliage. Before the trials, the wasps were individually kept at room temperature without any host in a glass tube for 18 h with microdrops of honey to prepare the wasps to the experimental conditions. In the olfactory bioassays, the responses of parasitoid females were analyzed by a v2 test. The null hypothesis was that parasitoid females had a 50:50 distribution across the two odour sources. All analyses were performed using SPSS version 20.0.

Higher numbers of *T. sinensis* females were attracted to the chestnut galls compared to nontarget cynipid oak gall hosts. The same result was obtained in the case of different proposed foliage: the chestnut foliage appeared to be more attractive for *T. sinensis* females than the oak foliage (*Quercus robur*). The combination of olfactory and visual stimuli provided by a fresh gall coupled with chestnut foliage elicited the strongest positive response. Our results indicate that both visual and olfactory cues are required to enable *T. sinensis* to successfully find suitable hosts. These findings may enhance our ability to manipulate *T. sinensis* for gall wasp management.

Keywords: invasive pest, Dryocosmus kuriphilus, Torymus sinensis, classical biological control, parasitoid

<footnote n="1">¹National Food Chain Safety Office, Plant Health and Molecular Biology National Reference Laboratory, Budapest, Hungary</footnote>

<footnote n="2">²Department for Forest Protection and Hunting, Croatian Forest Research Institute, Jastrebarsko, Croatia</footnote>
# Invasions of Waxwing *Bombycilla garrulus* in Polissya and Forest-steppe zone of Left-bank Ukraine

Vitalii Kazannyk, Anna Markova, Valentin Valentin Serebryakov

Biol. Dept., Taras Shevchenko National University, Kiev, Ukraine

Waxwing is a typical invasive species for Western Europe; its numbers depends on the harvest of berries and fruits. On the investigated territory, as well as within all Ukraine, birds migrate and winter, appear annually, however their amount differs on years and their appearance has more or less invasive character. During 2000-2015 in the Kyiv, Chernihiv, Sumy, Poltava and Kharkiv regions it was collected 100 phenological data personally and by means of questionnaire. When invasions occur Waxwings appear comparatively early, as a rule, in the second half of October - November, at once in great amount, and depart late - in March - April, sometimes stay later even till the beginning of May. In years with low numbers their autumn migration, as usual, takes place unnoticed and the first birds are often recorded already with the oncoming winter. They keep themselves in small flocks from few birds till some dozens of individuals. These years birds disappear unnoticed, often before calendar spring comes. In these cases in some sites they are difficult to be recorded. Autumn Waxwing arrival by regions: Kyiv: M = 18.XI, lim: 2.XI - 23.XI; Chernihiv: M = 26.X, lim: 10.X - 26.XI; Sumy: M = 29.X, lim: 10.X - 7.XI; Kharkiv: M = 18.XI, lim: 4.XI - 28.XI. Spring Waxwing departure by regions: Kyiv: M = 16.IV, lim: 5.IV - 9.V; Chernihiv: M = 24.III, lim: 15.II - 30.IV; Sumy: M = 28.III, lim: 26.II - 27. IV; Poltava: M = 25.III, lim: 14.II - 25.IV; Kharkiv: M = 20.III, lim: 5.III - 6.IV. During 2007-2015 81 flocks of birds were recorded in above mentioned regions. Low size of flock was 2 birds, maximal – 550. So average flock size is – 54.7 ± 10.4, CV = 170.9% (n = 81). Usually, during migration flocks are about 100 and even more birds. In winter, when Waxwings are dispersed on the territories for searching food, the sizes of their flocks are usually smaller – 50-80 birds. The last large Waxwing invasion on the investigated territory took place during winter 2012-2013.

Keywords: invasions, Waxwing, Ukraine
# Factors driving performance and distribution of *Ambrosia artemisiifolia* in the Czech Republic

Hana Skálová<fnref n="1" />, Lenka Moravcova<fnref n="1" />, Jan Wild<fnref n="1" />, Vendula Havlickova<fnref n="1" />, Karolina Hruskova<fnref n="2" />, Petr Pyšek<fnref n="1" />,<fnref n="3" />

*Ambrosia artemisiifolia*, an annual plant native to North America, was unintentionally introduced to Europe in the 19th century. Because of its negative impact on human health, agriculture and biological diversity it is nowadays considered as one of the most dangerous European alien weeds. From the Czech Republic it has been known since 1883, up to the 1990s recorded in about 80 localities, while about 300 localities have been recorded up to now. Current distribution of the species is influenced by density of communication corridors, weather and land use and further spread is highly likely, supported by ongoing climatic changes and increasing propagule pressure due to the rapid increase in abundance of the species in a wider area of central Europe. As an annual *A. artemisiifolia* is crucially dependent on the successful performance of juvenile plants. Seedling growth and development are influenced by temperature and nutrient levels. The thermal window ranges from 10 to 34 °C, with the seedling growth being faster under higher temperatures and nutrient supply with maximum biomass under 30 °C. The temperature optimum is higher than that of some potential native competitors and this fact should be taken into account when choosing species for competitive mixtures developed to suppress *A. artemisiifolia*. *Bromus erectus*, *Lotus corniculatus* and partly also *Phleum pratense* were identified as the successful competitors in a competition experiment.

Keywords: plant invasions, seedlings, environment, temperature, salinity, nutrients, competition

<footnote n="1">¹Institute of Botany, Academy of Sciences of the Czech Republic, Pruhonice, Czech Republic</footnote>

<footnote n="2">²Gymnazium Jiriho z Podebrad, Podebrady, Czech Republic</footnote>

<footnote n="3">³Department of Ecology, Faculty of Sciences, Charles University in Prague, Praha, Czech Republic</footnote>
**Life history of the invasive Chinese mitten crab (Eriocheir sinensis) in the Tagus estuary (Portugal).**

Pedro Anastácio<fnref n="1" />, Monica Marques<fnref n="1" />, Maria Águas<fnref n="1" />, Dagmara Wójcik-Fudalewska<fnref n="2" />, Monika Normant-Saremba<fnref n="2" />

The aim of this study was to characterize Chinese mitten crab (*Eriocheir sinensis*, Milne Edwards, 1853) population structure and dynamics in the upper Tagus river Estuary, Portugal. *E. sinensis* bycatch was obtained on an approximately monthly basis for 13 months. Data was collected and analyzed regarding population structure, female gonad development, fertility, condition and growth. This population presented an overall sex ratio of 1.54 (M/F) but sex ratio oscillated substantially along the year and almost no females were captured during the period from January to April. From March to May there were ovigerous females, but most were captured during a period of high salinity (3-7 PSU) in May. Each ovigerous female carried a mean number of 36350 eggs and this is low in comparison to other areas where the species is present. A large percentage of crabs (44.4%) presented loss of appendages; 41% with leg loss and 5.9% with chelae loss. In conclusion, the population in the Tagus estuary is well-established, but is short lived and its females have an unusually low fertility. These particular population traits may help to explain the apparent absence of population explosions in this area. Nevertheless, we recommend a continuous monitoring program for this species due to the high number of impacts in other invaded areas and also because invader population densities can remain low for very long periods before exploding.

Keywords: Population dynamics, growth, sex ratio, fertility, Chinese mitten crab

<footnote n="1">¹MARE - Center for Marine and Environmental Sciences University of Évora, Évora, Portugal</footnote>

<footnote n="2">²Department of Experimental Ecology of Marine Organisms, Institute of Oceanography, University of Gdansk, Gdynia, Poland</footnote>
# Plant invasions in The Macizo de Anaga Biosphere Reserve, Canary Island: who and how is a relict ecosystem invaded?

Alberto de la Rosa Padilla, Victoria Eugenia Martín Osorio, Wolfredo Wildpret de la Torre

University of La Laguna, Santa Cruz de Tenerife, Spain

The Macizo de Anaga Biosphere Reserve is located at the north-eastern end of Tenerife Island and it spreads over an area of 48,727.61 hectares. Since 1987 it is a Natural Protected Area included in Natura 2000 Network. In June 2015, it has been accepted by UNESCO as a Biosphere Reserve. It gathers 196 species of flora of which 21 are local endemism. Today it is one of the main leisure areas in Tenerife, a fact that has helped to retain the local population and their way of life, while enhancing their living conditions.

As human land uses provide propagules for colonization by alien species, one of our most important concerns was to know the amount of alien species that invade, their distribution and critical areas, the invasiveness of the different ecosystems and the future pathways of dispersal.

To achieve these objectives, we made 189 inventories all over the Reserve. We studied the bioclimatic conditions of the area (bioclimatic belts: thermotypes and ombrotypes), the exposition, the slope, the altitude and the different types of ecosystems. In all, 46 variants were analyzed. Eventually, we also revise the historical record related with the introduced species, checking the Herbarium TFC (University of La Laguna) and many other references. According to legal regulations, invaded area size and invasiveness status criteria, we selected the higher impact species, understanding these as the ones that submit a high invasiveness capacity, rapid dispersal and type of habitat invaded. As a result, we apply the Geobotanic Information System (GBOTIS, Martín Osorio et al., 2005) to obtain 79 maps of real and potential distribution.

Our findings pinpoint that of the 78 introduced species identified, 10 can be considered as higher impact species: *Opuntia maxima*, *Ageratina adenophora*, *Agave americana*, *Arundo donax*, *Ricinus communis*, *Oxalis pes-caprae*, *Pennisetum setaceum*, *Nicotiana glauca* and *Opuntia dillenii*. Altitude is the variable that has more influence on the invasion process. On the other hand, the warmest bioclimatic belts (upper and lower inframediterranean), riparian ecosystems (*Rubo-Salicetum canariensis*) and disturbed or successional plant communities (*Artemisio thusculae-Rumicetum lunariae*, *Rubio periclymeni-Rubetum* and *Myrico fayae-Ericetum arboreae*) are representative variables that are related with the invasion.

We conclude by outlining that early warning and early intervention systems are key strategies to tackle the spread of invasive species. We believe our results can be the account of a successful strategy to control/eradicate them.

Keywords: Geobotanic Information System, GBOTIS, bioclimatic belts, invasiveness, higher impact species
**Changes in valve movement behaviour of the zebra mussel *Dreissena polymorpha* associated with the impact of biotic environmental factors.**

Anna Dzierżyńska-Białończyk, Jarosław Kobak

Department of Invertebrate Zoology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, Torun, Poland

Zebra mussel *Dreissena polymorpha* (Pallas, 1771) is one of the most invasive species in the world, mainly due to its tolerance to a wide range of different environmental factors. Though there are many studies on its behaviour, only few of them concern the pattern of opening and closing the valves. Even those only deal with mussel responses to the presence of anthropogenic substances (environmental pollution). We assumed that zebra mussels are also capable of specific reactions to various biotic factors.

The aim of our research was to show how they react to the presence of kairomones of a predator (roach *Rutilus rutilus*) and alarm substance (secreted by injured conspecifics). We supposed that the scent of fish and alarm substance would be able to activate stress reactions (reduction in the overall time spent with open valves and induction of specific reactions, such as short opening periods or prolonged closure of valves to reduce the contact with the external environment). Besides, we expected different reactions of zebra mussels to the scent of fish whose diet contained *D. polymorpha* or not (the latter fed with larvae of chironomids).

We conducted all experiments in laboratory conditions using individuals collected from the Włocławek Reservoir (Central Poland, the lower Vistula River). The trials were recorded and then analysed with the specialised software for studying animal behaviour, Noldus Ethovision®XT. It follows the position of a colour mark on the movable mussel valve, resulting in a time series of percentage valve openings (relative to the maximum gaping).

We proved that the zebra mussel did not exhibit any specific reactions to the scent of roach itself. On the other hand, we noticed a strong response to the conspecific alarm substance, which may be the manifestation of behaviour related to a direct danger (the presence of a predator foraging at the moment, resulting in the production of conspecific alarm signals). Only in this case we observed relatively shorter time spent with open valves compared to the other variants, as well as the decrease in the mean percentage gaping. Thus, the valve movement response of the zebra mussel to predation pressure is based on the presence of conspecific alarm cue, rather than on predator identity, which makes it suitable to react to unknown danger sources in novel environments.

Keywords: Dreissena polymorpha, kairomones of predator, alarm substance, valve movement behaviour
Experimental effects of multiple regulating factors on cladoceran species richness
and community structure

Irina Feniova¹, Piotr Dawidowicz², Michail Gladyshev³, Nadezda Sushchik³, Marek Rzepecki⁶,
Iwona Kostrzewska-Szlakowska², Vladimir Razlutskij⁴, Andrew Dzialowski⁵

¹A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia

²University of Warsaw, Institute of Zoology, Warsaw, Poland

³Institute of Biophysics of Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia

⁴The Scientific and Practical Center for Bioresources, National Academy of Sciences of Belarus,
Minsk, Belarus

⁵Department of Integrative Biology, Oklahoma State University, Stillwater, United States

⁶Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland

Our goal was to determine how multiple environmental factors (e.g. resource levels, predation, cyanobacteria, and alien species) interact to regulate zooplankton communities in experimental aquatic food webs. We conducted several mesocosm experiments where we manipulated the presence/absence of alien large bodied cladocerans, zebra mussels, and fish under three levels of nutrient enrichment - mesotrophic, eutrophic and hypertrophic. Fish shifted the ratio between small and large bodied cladocerans in favour of small bodied species compared to controls. Fish also appeared to promote increases in cladoceran diversity through the coexistence of several smaller bodied taxa. Fish and nutrient enrichment increased blue-green algae and total chlorophyll concentrations. In contrast to fish, zebra mussels helped to promote the success of the large bodied alien *Daphnia*, but reduced the biomass of small bodied cladocerans. Population growth rates of large bodied species increased in the presence of zebra mussel, while growth rates of small bodied species decreased. Biochemical and elemental analyses demonstrated that zebra mussels reduced both the carbon(C):phosphorus(P) ratio and the concentrations of eicosapentaenoic acids (EPA) of the phytoplankton in the zebra mussel mesocosms. However, while EPA concentrations did not limit *Daphnia* growth rates, it did appear as though the C:P ratio in the zebra mussel treatment was below the range of their threshold values in control mesocosms. Therefore, an increase in the phosphorus concentrations of the seston may have favored the relatively P limited *Daphnia* in the presence of zebra mussels. Indeed, *Daphnia* biomass was the greatest in the treatment where zebra mussels were present. Combined, our results highlight the complex interactions of multiple factors that help to regulate zooplankton communities and size structure. Our research suggests that algal food quality may be an important factor regulating zooplankton communities and additional research is needed to better understand how food quality interacts with other important regulating factors.

Keywords: alien species, large and small bodied cladocerans, invasion mechanisms, PUFA, C:N:P ratios
# Effect of cultivating conditions on plant-soil feedbacks of alien *Impatiens* species

Anna Florianová<fnref n="1" />,<fnref n="2" />, Zuzana Münzbergová<fnref n="1" />,<fnref n="2" />

Plant-soil feedback, i.e. the relationship in which the plant affects the composition of the soil and such modified soil affects growth of the plant, can possibly be one of the key factors affecting plant invasiveness. While majority of plants show negative intraspecific feedback, positive intraspecific feedback is expected in invasive species that escaped their natural species-specific pathogens which thus cannot be accumulated in the soil and cannot negatively affect plant growth.

Positive (or less negative compared to natives) intraspecific feedback between invasive plant species and soil was demonstrated for several invasive species. However, in many studies no pattern like this was observed. A possible explanation for this inconsistency in the results might be the fact that the experiments are done under suitable conditions. Being in suitable conditions might mean that the plant is performing well even though the soil, in which it is cultivated, might be somewhat unfavourable.

To investigate the effect of cultivating conditions on results of plant-soil feedback experiments, we planted five alien *Impatiens* species in two-phase garden experiment. In the first phase, soil was cultivated by each of the species or left uncultivated. During the second phase, plants were grown in soil cultivated by the same species and in control uncultivated soil, both under four different cultivating conditions (two levels of watering x two levels of shading).

The feedbacks for total, above-ground and below-ground biomass and for root-shoot ratio were significantly affected by cultivating conditions. In three of the studied species, the feedback turned from negative to positive under certain conditions, however, these conditions differed among species. No effect of cultivating conditions on the feedback for germination was observed, with all plants germinating approximately the same in both cultivated and control soil.

Our results indicate that cultivating conditions play an important role in plant-soil feedbacks and that they should be considered in experimental designs. Multiple cultivating conditions or conditions closely resembling conditions in natural sites should thus be used to increase the realism of the results.

Keywords: plant-soil feedback, cultivating conditions, Impatiens

<footnote n="1">¹Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic</footnote>

<footnote n="2">²Institute of Botany, Czech Academy of Sciences, Pruhonice, Czech Republic</footnote>
# Untangling the complexity behind invasion success with an individual-based model

[Alex Gangur](https://www.example.com), Marco van de Wiel, Liz Trenchard, Katharina Dehnen-Schmutz

Coventry University, Centre for Agriculture, Water, and Resilience (CAWR), Ryton-on-Dunsmore, United Kingdom

Whether ecological communities assemble according to random processes – as predicted by neutral theories – or by repeatable, trait-based processes – as expected by niche-based theories – holds important implications for prediction in ecology, including biological invasions. Invasion biology has historically seen a focus on niche-based hypotheses, such as the enemy-release; novel weapons; and biotic resistance hypotheses, which invoke interactions and relationships between invaders and natives to explain invasion success (or failure). However, evidence in support of these niche-based hypotheses has been uneven and declining over time. Conversely, support has been mounting for neutral theories, particularly for the role of propagule pressure. Further, recent work suggests fundamental limits to the predictability of invasion dynamics due to inherit demographic stochasticity arising from repeated founder effects. Nonetheless, niche-based hypotheses remain important on a case-by-case basis. We have come to recognize invasions as complex, context-specific processes with no single explanatory factor to explain spread dynamics or invasion success. Future research needs to tease apart this complexity by focusing on the contributions of different properties of the invader, different properties of the recipient environment, and propagule pressure to invasion success at different stages of invasion and in different environmental contexts.

Few studies consider more than one or two hypotheses of invasion success, explicitly include transport processes, or couple pre-entry and entry processes with the post-entry stages of invasion. Individual-based models (IBMs) are well-positioned to address these challenges simultaneously because they: a) can easily incorporate idiosyncrasies endemic to different systems, b) can quantify stochasticity, and c) incorporate individual-level variation (e.g. in exact spatial arrangement). Here we present the development of a new spatially-explicit IBM. The model is designed to address the challenge of untangling multiple hypotheses of invasion success simultaneously. We do this using a distance model approach to model biotic and abiotic interactions, which are mediated by the resource budgets of individuals. Salient traits and processes are coded in a modular fashion, and can readily be added or removed depending on the system of interest. Invasive leguminous trees (Fabaceae) will be used as study species to evaluate our model.

Keywords: niche, community assembly, ibm, agent-based model, abm, invasion success
# Germination and seed viability of common ragweed (Ambrosia artemisiifolia L.) influenced by seed dimensions, origin and age

Rea Maria Hall, Gerhard Karrer

University of Natural Resources and Life Science Vienna Institute of Botany, Vienna, Austria

Common ragweed (Ambrosia artemisiifolia L.) is an annual Asteraceae species native to North America, which is highly invasive across Europe and has harmful impacts on a range of sectors, especially human health and agriculture. Especially its production of variable sized seeds is regarded as promoting its spread in different environments. In general, the seeds of common ragweed are dormant at maturity innately (primary dormancy) and require moist chilling (stratification) to come out of dormancy. Experiments with 12 Austrian populations of common ragweed were carried out to determine the influence of seed size (length and width), seed weight, seed origin and seed age on germination capacity. In addition, 2,3,5-Triphenyltetrazoliumchloride (TTC) tests were executed to determine the viability of the non-germinated seeds and to observe a possible correlation between morphological traits and the dormancy of seeds of common ragweed.

Generally, the TTC assay is a fast evaluation for seed viability. All respiring tissues are capable of converting a colourless compound to a carmine red coloured water-insoluble formazan by hydrogen transfer reaction catalysed by the cellular dehydrogenases. TTC enters both, living and dead cells but only living cells catalyse the formazan. Since a proper classification of intermediately coloured seeds (Fig.1) is still a challenge when determining viability rates (Starfinger et al. 2013) additional experiments were carried out on the basis of a joint-trial which was executed by 8 labs in 8 European countries using 4 populations of common ragweed to test the viability of the seeds by using TTC. Due to significant differences between the results of the various testing labs/persons, the 12 Austrian populations mentioned above were used for TTC testing to get a precise adjustment of the testing method as well as tight guideline for interpreting the results.

<figure><img src="image_14.png" /><figcaption>Fig. 1: Only living cells catalyse the formazan in TTC tests (Fotos: Hall)</figcaption></figure>

Keywords: 2,3,5-Triphenyltetrazoliumchloride, seed bank, ageing
# Does past competition affect invasiveness? Genetic differentiation and maternal effects in response to competition in an annual grassland species in its native and invaded range

Tina Heger<fnref n="1" />, Julia Ditton<fnref n="1" />, Andrew Latimer<fnref n="2" />

For an alien plant, the probability to establish successfully in a new range depends on its traits as well as on the biotic and abiotic characteristics of its new environment. Within species, traits can vary significantly, oftentimes leading to a match of a population's trait range with the respective environment. Population differentiation may thus lead to differences in the abilities of offspring to establish in a new environment. As for plants, competition is an important factor shaping species assemblages as well as population dynamics, the competition experienced in a specific population in the native range may influence the abilities of offspring from this population to establish in a new range.

The presentation will introduce results of a set of glasshouse experiments with the annual grassland species *Erodium cicutarium*. This species is native to Europe, and occurs as invasive alien species in many parts of the world, among them North America. We sampled populations in Germany and California differing in the level of competition experienced in the field, and grew these seed families in the glasshouse. Preliminary analyses indicate that the populations differ in how plants respond to shading in the greenhouse. One experiment, specifically addressing the effects of shading in the maternal environment on trait expression in the next generation, indicates that past competition triggers maternal effects. Two other experiments indicate the existence of genetic differences among the populations, leading to differences in the abilities of the offspring to respond to shading.

The results of the greenhouse experiments will be related to field data, and we will discuss in which situations past competition increases the probability for establishment success via maternal effects or genetic differentiation.

Keywords: Competition strength, context dependence, invasiveness, invasibility, novel interaction, ecological novelty, eco-evolutionary experience

<footnote n="1">¹Restoration Ecology, Technical University of Munich, Freising, Germany</footnote>

<footnote n="2">²Plant Sciences, University of California, Davis, Davis, United States</footnote>
**What causes alien aquatic plants to become invasive?**

Andreas Hussner

Institute of Botany Heinrich-Heine-University Geb. 26.13.O2 Universitätsstr. 1 D-40225 Düsseldorf
Germany, Düsseldorf, Germany

Invasive alien aquatic plants (IAAPs) cause significant ecological and economic impact. The number of introduced plants which become invasive is much higher for aquatic than for terrestrial plants. For aquatic plants, some studies provide detailed information on the biology of alien aquatic invasive species, but only a few traits have been reported as closely linked to successful aquatic plant invaders. However, a comprehensive knowledge of plant traits which are linked to aquatic plant invasiveness is still lacking. Moreover, some factors which will have most likely had an effect on the invasive success of alien aquatic plants have been almost neglected in the past. During this talk, introduction pathways, spread mechanisms (both sexual and asexual), growth characteristics (growth forms, growth rates, habitat requirements) and physiological attributes (light and temperature optima, carbon concentrating mechanisms (CCMs)) of IAAPs will be presented. Recent findings give some new insights into these attributes linked with the IAAPs success and will help to identify potential IAAPs in the future.

Keywords: Invasive aquatic plants, growth, spread, physiology, characteristics
**Density of prey as a factor modifying the anti-predator behaviour of amphipods**

Łukasz Jermacz, Barbara Szatkowska, Joanna Zielska, Jarosław Kobak

N. Copernicus University, Department of Invertebrate Zoology, Torun, Poland

To minimalize predation efficiency, prey uses diverse strategies, from simple defences, when only one aspect of behaviour is modified, to complex mechanisms, such as grouping involving simultaneously the dilution, encounter-dilution and predator confusion effects. The majority of research does not take into account the fact that the anti-predator strategy may vary depending on the density of conspecifics in the environment.

We studied the anti-predator strategy (including aggregation behaviour and locomotion) of an invasive gammarid *Dikerogammarus villosus* (Amphipoda, Crustacea) at different densities (5, 10 and 15 individuals per an area of 0.025 m²) in the presence of kairomones of a fish predator: the racer goby *Babka gymnotrachelus*. Furthermore, to check the effectiveness of the gammarid anti-predator behaviour, we exposed them under similar conditions to fish predation.

At the low density (low probability of conspecific encounters), gammarids responded to predators by moving over longer distances. In contrast, the decrease in moved distance was noted at the highest density, when the aggregation level was significantly higher than at lower densities. Moreover, gammarids always increased their aggregation level in the presence of predators. Gobies most effectively foraged on immobile single gammarids. Their predation efficiency was reduced at the highest gammarid density. Fish preferred single gammarids over aggregated individuals.

To summarize, gammarids respond to predators by modifying their movement, which, depending on the density-related possibility of conspecific encounters, leads to leaving a predator area at low density or finding conspecifics and staying in an aggregation at high density. Both these options were effective defence strategies.

Our study was supported by a grant of National Science Centre 2013/09/N/NZ8/03191.

Keywords: anti-predator behaviour, group living, Dikerogammarus villosus, flexible defence strategy, foraging, predator kairomones, predator-prey interaction
# Estimation of seed longevity in artificial soil seed banks of common ragweed
(Ambrosia artemisiifolia)

Gerhard Karrer<fnref n="1" />, Rea Maria Hall<fnref n="1" />, Felicia Lener<fnref n="1" />, Nina Waldhaeuser<fnref n="1" />, Gabriella Kazinczi<fnref n="2" />, Ildikó Kerepesi<fnref n="2" />, Sándor Máté<fnref n="2" />, Ulrike Soeltner<fnref n="3" />, Uwe Starfinger<fnref n="3" />, Arnd Verschwele<fnref n="3" />, Solveig Mathiassen<fnref n="4" />, Per Kudsk<fnref n="4" />, Robert Leskovšek<fnref n="5" />, Andrej Simoncic<fnref n="5" />

Two experiments, started more than 100 years ago in the US, have shown that seeds of common ragweed (Ambrosia artemisiifolia L.) can survive up to 39 years in soil seed banks. Since no data are available for alien European ragweed populations, the HALT-Ambrosia team set up a long-term experiment to test ragweed seed longevity from different origins buried at 2 depths at 5 locations in Europe. Seed lots from Hungary (Kaposvar 2010) were buried in each country; additionally, a second seed lot from other origins was buried at each site: Germany used seeds from Domsdorf (Germany 2010); Austria and Hungary used seeds from Hagenbrunn (Austria 2011); Denmark and Slovenia used seeds from Unterpurkla (Austria 2010). In the winter 2011/12 seeds were buried at 5-8 cm and 25 cm depth respectively in fields or lawns in the surrounding of Vienna (Austria), Braunschweig (Germany), Kaposvar (Hungary), Flakkebjerg (Denmark) and Ljubljana (Slovenia). Fifty seeds were put in fine mesh polyethylene nets and buried at the two soil depths. Every year in early spring until 2022 a randomly chosen subset of five polyethylene nets per depth and origin were/will be dug out. Intact seeds are counted and tested for viability by germination test (wetted in petri dishes, 12h light at 25°C, 12h darkness at 15°C) for 4 weeks; the remaining not germinated seeds are subsequently tested for viability with the TTC-test. Germinability was expressed as percentage of initial number of seeds.

In the first year (spring 2013), the excavated seeds from Kaposvar still showed relatively high viability rates of 40-97% (mean of 88% at soil depth 5-8 cm) and 48-98% (mean of 89% at soil depth of 25 cm). The seed lots from Hagenbrunn lost viability (35-82% at 5-8 cm depth and 38-89% at 25 cm), similarly as the seeds from Unterpurkla (23-42% at 5-8 cm depth and 19-43% at 25 cm). Mean survival rates of the Domsdorf seeds were 91% at 5-8 cm and 98% at 25 cm depth. The laboratories tried to follow the manual as strictly as possible; nevertheless, variation in the estimation of viability between the labs was relatively high.

Data from subsequent years (2014, 2015) showed less variation between laboratories. The trend observed in the first year that Kaposvar seeds survived at higher rates than the other seed lots continued. The differences in ragweed seed survival with respect to burial depth tends to increase with duration of burial, but without significant differences up to now.

Keywords: Ambrosia artemisiifolia L., seed burial, germination, viability, TTC-test

<footnote n="1">¹Institute of Botany, University of Natural Resources and Life Sciences, Vienna, Austria</footnote>

<footnote n="2">²Kaposvár University, Kaposvár, Hungary</footnote>

<footnote n="3">³Julius Kühn Institute, Braunschweig, Germany</footnote>

<footnote n="4">⁴Aarhus University, Slagelse, Denmark</footnote>

<footnote n="5">⁵Agricultural Institute of Slovenia, Ljubljana, Slovenia</footnote>
**Intraspecific plant-soil feedback as an explanation of plant invasiveness**

Pavlína Knobová<fnref n="1" />, Anna Floriánová<fnref n="1" />, <fnref n="2" />, Zuzana Münzbergová<fnref n="1" />, <fnref n="2" />

Intraspecific plant-soil feedback is a relationship in which plant affects the composition of the soil and such modified soil affects growth of the same plant species. This relationship and its intensity may be linked with plant dominance and invasiveness. Dominant species can alter the composition of the soil in their favour and thus show positive intraspecific plant-soil feedback. As the invasive species are commonly being dominant in their new environment, it can be expected that intraspecific positive plant-soil feedback could be an important factor allowing the invasive species to achieve their dominant position and become invasive.

To test if the existence of positive intraspecific feedback could be a general mechanism underlying plant invasiveness we compared intraspecific plant-soil feedback in a group of invasive and introduced, but non-invasive, plants in the Czech Republic. We did this using a preselected set of 23 introduced species, which were planted in soil with their own history and in unaffected soil and then compared. More species will be tested in the future.

Seven of the twenty-three tested species responded significantly to the type of soil in terms of growth, but only *Conyza canadensis* showed positive intraspecific feedback. These seven species are both invasive and non-invasive. Seed germination was, however, strongly influenced by soil type - thirteen of twenty-three species have higher germination in the affected soil. The results thus suggest that positive plant-soil feedback may be more common for germination than for subsequent plant growth. Data on more species are needed to properly assess differences in feedback between invasive and non-invasive introduced species.

Keywords: plant-soil feedback, plant invasiveness

<footnote n="1">¹Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01 Praha 2, Czech Republic, Praha, Czech Republic</footnote>

<footnote n="2">²Institute of Botany, Czech Academy of Sciences, Zámek 1, 252 43 Pruhonice, Czech Republic, Praha, Czech Republic</footnote>
**Interspecific competition as a factor modifying the spreading rate of invasive**
**Ponto-Caspian gammarideans**

Jarosław Kobak<fnref n="1" />, Michał Rachalewski<fnref n="2" />, Karolina Bacela-Spychalska<fnref n="2" />

Several species of Ponto-Caspian gammarids have invaded main European waters, affecting benthic communities by predation and competition. The ranges and dispersal rates of particular species vary across Europe, which may result from their interspecific interactions, accelerating or reducing migrations. We checked this hypothesis by testing the interference competition among three co-occurring invaders: *Dikerogammarus villosus*, *D. haemobaphes* and *Pontogammarus robustoides*.

We used 140-cm long tanks (with gravel substratum providing shelters for the gammarids), divided into seven compartments along the tank length. We introduced 25 "residents" into the outermost compartment, separated with a barrier. After 1h, we introduced 25 "intruders". After the next 1h, we removed the barrier and the gammarids could disperse in the tank. After 4 or 20h, we counted the gammarids in particular compartments. We tested all pairwise species combinations and single-species controls.

*D. villosus* had significantly displaced the other species (*P. robustoides* only after 4h) and reduced its own motility after 20h in their presence. *P. robustoides* stimulated the short-time migrations of *D. villosus* intruders and of all *D. haemobaphes* individuals. As *P. robustoides* migrated spontaneously much more than *Dikerogammarus* spp., its impact on the other species decreased after longer time. *D. haemobaphes* stimulated the short-time movement of *P. robustoides* intruders but reduced the long-time relocation of this species and that of *D. villosus*.

In general, the dispersal increased in the presence of stronger competitors (*D. villosus* and *P. robustoides*, especially introduced as residents) and decreased in response to weaker competitors (*D. haemobaphes*). The stimulation of dispersal was probably caused by competitive displacement by stronger competitors. The reduction of migration might have resulted from the increased defence of currently occupied shelters by the stronger species or from decreased competitive pressure of heterospecifics compared to the intraspecific competition. Thus, competitive interactions may affect the dispersal of invasive gammarids and contribute to the fastest spread of the weakest competitor, *D. haemobaphes*, whereas the strongest species, *D. villosus* would be the latest newcomer. Such order of appearance was observed in the field in the central migration corridor for the Ponto-Caspian fauna, including the Dnieper, Prypiat, Bug and Vistula rivers.

Our study was supported by National Science Centre grants 2011/03/D/NZ8/03012 and 2012/05/B/NZ8/00479.

Keywords: Dikerogammarus, Pontogammarus, competitive displacement, spread rate, interspecific interactions, freshwater environment

<footnote n="1">¹Department of Invertebrate Zoology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, Torun, Poland</footnote>

<footnote n="2">²Department of Invertebrate Zoology and Hydrobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland</footnote>
**Biotic barriers to naturalization: a weak force or simply not adequately detected?**

Richard Mack

School of Biological Sciences Washington State University Pullman, WA 99164 USA, Pullman, United States

Immigrants' naturalization and even subsequent invasion in a new range through escape from native enemies has long been recorded. In contrast an alternative outcome is poorly documented: the immigrants' (or their descendants') extinction by a diverse array of biotic agents (e.g., parasites and predators) native to the new range. How important are native organisms as biotic barriers to naturalization? Current attempts to comprehensively examine and quantify this issue have been restricted to the literature surveys readily available from Internet websites (e.g. Agricola, CAB abstracts, Web of Science). Reasons for the failure of such web-based searches to accurately gauge the effect of organisms acting as biotic barriers to naturalization include i) many web-based abstracting services do not record articles that pre-date 1900 or the internet, ii) examples in the grey literature can be difficult to detect or go unreported altogether, iii) web-based searches for examples of biotic barriers often encompass only ecological journals and overlook sources further afield (e.g. agronomy, entomology, fisheries, parasitology, plant pathology, and veterinary pathology). An especially relevant and as yet largely untapped discipline for investigation is forestry, particularly tropical forestry. Tropical foresters at the end of the 19th and beginning of the 20th century diligently attempted to introduce merchantable tree species into new ranges. Many of these trials failed repeatedly; tropical foresters were diligent in recording the outcome and the apparent cause of plantation failures in now defunct local journals. Furthermore, recording even a fraction these on-going extinctions, whether in deliberate field trials or through anecdotal observation in nature is not widely practiced today. As a result, evidence of the strongest and swiftest-acting biotic barriers soon disappears, i.e., the immigrants die and decompose without detection.

Keywords: predators, parasites, web-linked searches, tropical forestry
# Does phylogenetic distance between invasive and native plants matter?

Eva Maria Malecore, Mark van Kleunen

University of Konstanz, Konstanz, Germany

In the field of (plant) invasion biology one of the major goals is to determine the factors that allow an alien species to become invasive. The phylogenetic distance of an invasive plant to the native community may play a role in its establishment success in that community. Alien plants more closely related to native plants may suffer more from competition, because of increased niche overlap (Darwin's naturalization hypothesis). On the other hand, relatedness and similarity in niche requirements can be linked to preadaptation, and thus could facilitate invasion.

To assess the role of phylogenetic distance in the establishment success of alien plant species, we used an already existing dataset, where alien plant species where introduced in grassland sites in Switzerland.

We calculated three phylogenetic distance measures:

(1) the mean phylogenetic distance to all resident native species,

(2) the phylogenetic distance to the most abundant resident native species, and

(3) the phylogenetic distance to the nearest relative among the resident native species.

Overall, we found that alien plant species closer related to the native community are less successful than distantly related species.

Keywords: Darwin's naturalization hypothesis, alien plants, invasive plants
**Epiphytes invasive species on the Canary Island date palm (Phoenix canariensis H. Wildpret) in the Canary Islands and Andalusia, Spain.**

Victoria Eugenia Martín Osorio<fnref n="1" />, Wolfredo Wildpret de la Torre<fnref n="1" />, Wolf-Hermann Wildpret<fnref n="2" />

Over the years we carried out a study and monitoring of epiphytes vascular plants installed naturally in the trunk of the Canary Island date palm (Phoenix canariensis H. Wildpret).

The Canary Island date palm is an endemic species of the Canary archipelago distributed by the world as an ornamental plant. In the Canaries their artificial distribution extends from sea level up to 1000 m.s.l.

Exceptionally some specimens have reached 1600 m (Vilaflor, Tenerife). There are some semi-anthropic palm groves that are renewed naturally.

Epiphytism on the palm tree has been detected in over 2000 specimens from near sea level on coastal walks to those in the midlands. At these altitudes they are subject to the humid climate of the trade winds and there are a high number of epiphytic species of cyanobacteria, briolichenic communities and even some Basidiomycetes.

Until now we have recorded some eighty different vascular species established on the stipe phorophyte mentioned.

In this communication the high presence of three invasive species is pointed out: *Ficus microcarpa* L., *Ficus rubiginosa* Desf. ex Vent., and *Nicotiana glauca* Graham.

Keywords: Epiphyte, Phoenix canariensis, Palm tree, Ficus microcarpa, Ficus rubiginosa, Nicotiana glauca

<footnote n="1">¹Department of Botany, Ecology and Plant Physiology Universidad de La Laguna, Islas Canarias, La Laguna, Islas Canarias, Spain</footnote>

<footnote n="2">²Bazán-Vistazul 14, El Rosario Tenerife, Spain</footnote>
**Can functional traits be used to predict plant invasion potential on a Sub-Antarctic Island?**

Rabia Mathakutha<fnref n="1" />, Christien Steyn<fnref n="1" />, Brad Ripley<fnref n="2" />, Peter le Roux<fnref n="1" />, Barnabus Daru<fnref n="1" />, Michelle Greve<fnref n="1" />

Non-indigenous species are a major conservation threat in the sub-Antarctic region, where the small size and low diversity of the islands render them vulnerable to biological invasions. However, what determines whether alien arrivals become successful invaders or not has not been explored for the region. We used a trait-based approach to understand whether the success of invasive plant species can be explained by differences in functional traits between indigenous and alien plant species. A number of functional traits of all alien and indigenous higher plant taxa on sub-Antarctic Marion Island were collected from different vegetation types, substrates, aspects and altitudinal gradients using a stratified sampling design. The value of each trait was averaged per species. To test whether native, non-invasive alien and invasive species differ in their functional traits, general linear models were performed for height, leaf area, specific leaf area (SLA) and electrolyte leakage as an indicator of frost sensitivity. Our findings showed that only SLA differed significantly between the three status groups. However, when phylogeny was accounted for by fitting a phylogenetic generalised least-squares model, all of the four traits analysed differed significantly for native, non-invasive alien and invasive species. A key finding was the high SLA and low frost tolerance shown by invasive species in this study relative to native and non-invasive alien species. These results suggest that invasive species have a capacity for faster growth rates and enhanced resource acquisition due to high SLA. This may predispose species to become invasive by allowing them to efficiently outcompete extant vegetation. High SLA also corresponds with relatively low investment in leaf defences, this is demonstrated by the low frost tolerance shown by invasive species in this study. The consequences of this finding are worrying for Marion Island, given that Marion Island has become considerably warmer; with this trend expected to continue into the future, we may expect invasive species to spread as conditions will become milder and so more suitable for a range of plant species. In summary, understanding which functional traits favour invasion success and potential may provide a useful tool to minimise future invasions.

Keywords: Plant functional traits, Invasive species, Marion Island, Sub-Antarctic islands, SLA

<footnote n="1">¹Department of Plant Science, University of Pretoria, Private Bag X20, 0028, Hatfield, South Africa</footnote>

<footnote n="2">²Department of Botany, Rhodes University, Po Box 94, 6140, Grahamstown, South Africa</footnote>
**Do various types of forests differ in alien species composition?**

Jana Medvecká, Ivan Jarolímek, Katarína Hegedüšová, Iveta Škodová, Katarína Botková, Denisa Bazalová, Mária Petrášová

*Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, 845 23 Bratislava, Bratislava, Slovakia*

So far only few studies focused on alien species in forest ecosystems, as forests appeared to be more resistant to invasions. Recent studies revealed that it was only a temporary phenomenon and many forest habitats are continually being invaded by alien species.

The aim of our study was to find out how various type of forest habitats in Slovakia differ in the species composition of alien species. For the purpose of this analysis we have used database of forest relevés, included in the Central database of phytosociological relevés of Slovakia together with newly collected relevés that consisted of 10,392 relevés. From the original dataset we have omitted relevés of extreme sizes and relevés collected before 1960. Resulting database consisted of 5748 relevés. Relevés were classified within one of 23 EUNIS habitat types, based on the syntaxa, where they belonged. Vascular taxa were classified as either native or alien (archaeophytes, neophytes), based on the Inventory of alien flora of Slovakia (Medvecká et al. 2012). Fidelity and frequency of the species, calculated by software JUICE (Tichý 2002), were used to compare occurrence of various (most frequent) alien species in the analysed habitats.

This will help us to find out:

i) whether some of the forest habitats possess specific alien species combinations and

ii) whether various alien plants prefer some specific forest habitats.

Some of the forest habitats contain several alien species with rather high fidelity, such as *Robinia pseudoacacia* plantations with several species of archaeophytes (e.g. *Anthriscus cerefolium*, *Bromus sterilis*), or Riverine *Salix* woodlands with several species of invasive neophytes (e.g. *Aster novi-belgii*, *Acer negundo*). On the other hand, some species, such as *Impatiens parviflora*, are frequently found in various types of forest habitats and are not bound to any of them. The results will serve as valuable scientific base for the qualified forest management especially in the protected regions.

This contribution was supported by grant VEGA 2/0051/15.

Keywords: EUNIS, fidelity, invasive plants, archaeophytes, neophytes
**Archaeophytes vs. neophytes: which are more successful invaders in high
mountain?**

Jana Medvecká, Jana Májeková, Mária Zaliberová, Ivan Jarolímek

Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, 845 23, Bratislava, Slovakia

Mountain ranges are biodiversity hotspots and home of many endemic, rare and endangered species, which are being continuously affected by climate change, eutrophication and human-induced disturbance. As a result, they are getting more susceptible to invasions by alien plants.

The aim of the presented study is to evaluate characteristics of non-native plants of the Tatra Mts, and to analyse patterns of their distribution, especially with respect to the different residence times of the alien plants. The distribution data of alien species were collected during years 2009-2011 along the tourist routes in mountain valleys, along main roads, along railways, and in the surrounding of mountain chalets.

Together we have found 51 alien taxa in the Tatras – 20 neophytes and 31 archaeophytes. Majority of alien species, found in the Tatras, is widely distributed and abundant in Slovakia and occurs in most of the phytogeographic regions. Alien species that were more frequent in the Tatras, reached also higher altitudes. Altitudinal maxima of archaeophytes and neophytes and their frequency in the Tatras did not differ significantly, indicating that even though archaeophytes had more time to spread in the region, the mountain conditions were not suitable for majority of them, as they prefer different ecological conditions. Our results suggest that even though we have recorded more species of archaeophytes than neophytes, both of them seem to be almost equally successful invaders in the Tatra Mts.

This research was funded by VEGA 2/0098/11, VEGA 2/0121/09 and VEGA 2/0090/12.

Keywords: alien plants, plant invasions, altitude, Tatra Mts, Central Europe
**Effects of seed traits variation on seedling performance of the invasive weed, *Ambrosia artemisiifolia* L.**

Arnaud Monty, William Ortmans, Grégory Mahy

*Biodiversity and Landscape, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium*

Seedling performance can determine the survival of a juvenile plant and impact adult plant performance. Understanding the factors that may impact seedling performance is thus critical, especially for annuals, opportunists or invasive plant species. Seedling performance can vary among mothers or populations in response to environmental conditions or under the influence of seed traits. However, very few studies have investigated seed traits variations and their consequences on seedling performance.

Specifically, the following questions have been addressed by this work:

1) How the seed traits of the invasive *Ambrosia artemisiifolia* L. vary among mothers and populations, as well as along the latitude;

2) How do seed traits influence seedling performance;

3) Is the influence on seedlings temperature dependent.

With seeds from nine Western Europe ruderal populations, seed traits that can influence seedling development were measured. The seeds were sown into growth chambers with warmer or colder temperature treatments. During seedling growth, performance-related traits were measured.

A high variability in seed traits was highlighted. Variation was determined by the mother identity and population, but not latitude. Together, the temperature, population and the identity of the mother had an effect on seedling performance. Seed traits had a relative impact on seedling performance, but this did not appear to be temperature dependent. Seedling performance exhibited a strong plastic response to the temperature, was shaped by the identity of the mother and the population, and was influenced by a number of seed traits.

Keywords: Achene variability, Competitive ability, Cotyledon area, Phenotypic plasticity, Seed colour, Seed mass
**Do invasive and non-invasive plant species differ in how long their seed persist in the soil seed bank?**

Lenka Moravcová<fnref n="1" />, Hana Skálová<fnref n="1" />, Margherita Gioria<fnref n="1" />, Petr Pyšek<fnref n="1" />,<fnref n="2" />

Recent research indicates that among reproductive traits promoting plant invasiveness, production of seed persisting in the soil for a long time plays a role. To test the relationship between soil seed banks and invasiveness experimentally, we conducted a burial experiment to find out if there are differences in seed persistence between invasive and non-invasive alien plant species. Seed of 73 species that are alien in the Czech Republic (35 invasive and 37 non-invasive) were collected in the field, tested for viability and buried in nylon bags in the soil in a common garden at the Institute of Botany, Pruhonice. Seeds were exhumed once a year (spring 2014, 2015, 2016), and the fraction of germinated or decayed seeds, and of non-germinated but viable seeds, was determined in each sample. This allowed us to assess seed persistence/viability after 1.5, 2.5 and 3.5 years of burial in the soil.

Preliminary results after two years suggest that invasive and non-invasive species differ in seed persistence. Invasive species tend to persist longer in the soil and have thus potential to form larger and persisting for longer time seed banks than non-invasive species. Seeds of all invasive species were viable or germinated to some percentage after 1.5 year of burial in the soil, while 16% of non-invasive species did not survive during this burial period. Moreover, the majority of invasive species showed a high seed survival percentage (survival category 75-100%), while only low percentage of non-invasive species germinated or were viable after this period in this survival category. After 2.5 years of burial in the soil, the majority of invasive species showed a seed survival percentage ranging from 5-25%, while non-invasive species were distributed rather evenly among all other survival percentage categories, with only 5% species in highest survival category. The differences in seed persistence between two categories of alien plants after 3.5 years of burial will be presented and discussed.

Keywords: seed persistence, burial experiments, seed viability, invasive status

<footnote n="1">¹Institute of Botany, Academy of Sciences of the Czech Republic, Pruhonice, Czech Republic</footnote>

<footnote n="2">²Department of Ecology, Faculty of Sciences, Charles University in Prague, Prague, Czech Republic</footnote>
**First come first served: priority effect benefits *Ambrosia artemisiifolia* L. more than other ruderal Asteraceae species**

William Ortmans, Grégory Mahy, Arnaud Monty

*University of Liege, Gembloux, Belgium*

In plant communities, species that start their development earlier can be advantaged over the other species. This advantage given by an earlier development is called the *priority effect* and can have an important impact on plant communities' composition and structure. This is particularly true in ruderal habitats where disturbances are frequent. Common ragweed (*Ambrosia artemisiifolia* L.) is an invasive plant causing a health crisis in Europe due to its allergenic pollen. This annual plant is highly affected by competition, has an opportunistic behaviour, and is often found in ruderal habitats.

The aim of this study was to evaluate the role the priority effect plays in the invasion success of common ragweed, by determining if the species is able to benefit more of the priority effect than other comparable species from ruderal habitats.

We selected eight annual species from the Asteraceae family, growing in ruderal habitats in Belgium, among which *A. artemisiifolia*. At the beginning of the experiment, seedlings of each species were individually planted in separated pots. Three weeks later, 7 other seedlings (one per species) were planted in the pots in order to have 8 seedlings from 8 different species in each pot, with one 3 weeks older than the others. After two months, all the plants were cut at ground level, the above ground biomass was measured and the number of flowering head counted.

The results showed that *A. artemisiifolia* benefited more from the priority than all the other species: its number of flowering heads was multiplied by 600 on average and its aboveground biomass by 30, when in priority. Furthermore, when in priority *A. artemisiifolia* was the species that had the biggest negative impact on the development of the 7 other species.

These results highlighted the important advantage that *A. artemisiifolia* is able to take when starting its development without competition.

Keywords: Priority effect; ragweed; reproductive performance; community
# Zebra mussel beds: a perfect shelter for prey or perfect feeding ground for Ponto-Caspian gobies

Małgorzata Poznańska<fnref n="1" />, Łukasz Jermacz<fnref n="1" />, Tomasz Kakareko<fnref n="2" />, Karolina Bącela-Spychalska<fnref n="3" />, Daniel Prądzynski<fnref n="1" />, Małgorzata Łodygowska<fnref n="1" />, Karolina Montowska<fnref n="1" />, Jarosław Kobak<fnref n="1" />

Aggregations of the Ponto-Caspian invasive zebra mussel (Dreissena polymorpha) constitute a suitable habitat for macroinvertebrates, considerably increasing their abundance and providing effective anti-predator protection. Thus, the overall effect of a mussel bed on particular predator species may vary from positive to negative, depending on prey density increase and predator ability to prey in a structurally complex habitat. Alien Ponto-Caspian goby fish are likely to be facilitated in their novel areas by zebra mussels, provided that they are capable of utilizing mussel beds as habitat and feeding grounds. We ran laboratory experiments to find the prey (chironomid larvae) density (from ca. 500 to 2000 individuals m⁻<fnref n="2" />) in a mussel bed that makes it a more beneficial feeding ground for the racer goby *Babka gymnotrachelus* (RG) and western tubenose goby *Proterorhinus semilunaris* (WTG) compared to sandy and stone substrata (containing the basic prey density of 500 ind. m⁻<fnref n="2" />). Moreover, we checked how food availability affects habitat selection by fish. Mussel beds became more suitable for fish than alternative mineral substrata when food abundance was at least twice higher (1000 vs. 500 ind. m⁻<fnref n="2" />), regardless of fish size and species. WTG was associated with mussel beds regardless of its size and prey density, whereas RG switched to this habitat when it became a better feeding ground than alternative substrata. Larger RG exhibited a stronger affinity for mussels than small individuals. WTG fed more efficiently from a mussel bed at high food abundances than RG. A literature review has shown that the increase in chironomid density, which in our study was sufficient to make a mussel habitat an attractive feeding ground for the gobies, is commonly observed in mussel beds in the field. Therefore, we conclude that zebra mussels may affect positively the alien goby species and are likely to facilitate their establishment in novel areas, contributing to the invasive meltdown in the Ponto-Caspian invasive community.

This research was supported by Polish National Science Centre (NSC grant no. 011/03/D/NZ8/03012).

Keywords: Babka gymnotrachelus, Proterorhinus semilunaris, Dreissena polymorpha, invasive meltdown, ecosystem engineers

<footnote n="1">¹Nicolaus Copernicus University, Faculty of Biology and Environmental Protection, Department of Invertebrate Zoology, Torun, Poland</footnote>

<footnote n="2">²Nicolaus Copernicus University, Faculty of Biology and Environmental Protection, Department of Hydrobiology, Torun, Poland</footnote>

<footnote n="3">³University of Lodz, Department of Invertebrate Zoology and Hydrobiology, Lodz, Poland</footnote>
**Coevolutionary relationship drives population-specific responses to an invasive
species**

Martin Reichard<fnref n="1" />, Karel Douda<fnref n="2" />, Mirosław Przybylski<fnref n="3" />, Carl Smith<fnref n="1" />, <fnref n="4" />

While our understanding of the mechanisms of arrival and establishment of non-native species is improving, predicting their impacts remains a challenge. Interacting species often express specific reciprocal adaptations to co-exist, leading to dynamic coevolutionary associations that can be distorted by new partnerships that emerge as a consequence of the non-native species arrival. The coevolutionary associations often vary across species range, forming a mosaic of coevolutionary hotspots and coldspots. Hence, as populations of a species are variable, the impact of non-native species on local taxa could crucially depend on population-specific traits and adaptations of both native and non-native species. Bitterling fishes are brood parasites of unionid mussels and unionid mussels, in turn, produce larvae that parasitize fish. We used common garden experiments to measure three key elements in the bitterling-mussel association among two populations of an invasive mussel (Anodonta woodiana, Unionidae) and four populations of European bitterling (Rhodeus amarus, Cyprinidae). The impact of the invasive mussel varied between geographically distinct R. amarus lineages and between local populations within lineages. The capacity of parasitic larvae of the invasive mussel to exploit R. amarus was higher in a Danubian than in a Baltic R. amarus lineage and in allopatric than in sympatric R. amarus populations. Maladaptive oviposition by R. amarus into A. woodiana varied among populations, with significant population-specific consequences for R. amarus recruitment. We suggest that variation in coevolutionary states may predispose different populations to divergent responses. Given that coevolutionary relationships are ubiquitous, population-specific attributes of invasive and native populations may play a critical role in the outcome of invasion. We suggest that a conceptual framework that considers invasive populations rather than species can provide deeper insight into the impact of invasions.

Keywords: coevolutionary association, aquatic ecosystem, fish, union mussels, freshwater,
population

<footnote n="1">¹Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic</footnote>

<footnote n="2">²Department of Zoology and Fisheries, Czech University of Life Sciences Prague, Prague, Czech Republic</footnote>

<footnote n="3">³Department of Ecology & Vertebrate Zoology, University of Lodz, Lodz, Poland</footnote>

<footnote n="4">⁴School of Biology, University of St Andrews, St Andrews, United Kingdom</footnote>
**Climate mismatch in plant invasions contributes to the existence and length of lag phases**

*Philipp Robeck, Mohsen Mesgaran, Roger Cousens*

*University of Melbourne, Melbourne, Australia*

The ability to predict the probability of introduced species to become invasive relies on the understanding of a multitude, not mutually exclusive, mechanisms. Multi-species studies permit to examine environmental, reproductive and dispersal factors responsible for the commonly described time lag in invasive populations. Drivers of the different stages along the introduction-naturalization-invasion continuum provide insights on opportunities and limitations of correlative species distribution models.

This study investigates drivers and processes influencing the transition from naturalisation to invasiveness and the degree of climate matching responsible for the lag phenomena in introduced plant populations. We discuss the degree of climatic niche conservatism between the two invasion stages, a key assumption of species distribution models.

Generalised linear models were fitted to herbarium data of 2,818 naturalised exotic species of Australia and New Zealand to determine the existence of lag phase and length. The degree of difference between the two climatic niches, described by eight Bioclim variables, was analysed and examined in relation to the change in geographic space. The results were tested for relationships between dispersal and reproductive traits and phylogenetic data aiming to identify drivers and patterns influencing the lag phenomena and the degree of climate dissimilarity.

Our analysis of 2,818 time series shows lag phases in only 30% of the tested plant species. The transition from a lag to an expansion phase coincided with a shift (expansion) in climate niche in the majority of tested species (86%) corroborating the view that climate mismatch has significantly contributed to the existence of lags. Climate niche expansion was positivity correlated with geographical movement suggesting that most lags have ended once long dispersal (or independent introduction) has placed some propagule in a different region with seemingly more suitable climate. Adaptation-mediated termination of lag phase will gain more support, should the increase in the abundance of an invader occur in the vicinity of the first introduction foci (lag region), which harbours marginal climates. This was not the case in the majority of the tested species.

We may, therefore, conclude that for most plant invaders that undergo a period of lag before population explosion, climate uncoupling is the most parsimonious model explaining such a biphasic behaviour.

Keywords: biological invasion, lag phase, climatic niche, niche conservatism, functional traits, geographic range
# Behavioural changes in biological invasions: taxonomic differences and underlying mechanisms

Florian Ruland<fnref n="1" />, <fnref n="2" />, <fnref n="3" />, Jonathan Jeschke<fnref n="1" />, <fnref n="2" />, <fnref n="3" />

Behavioural changes are recognized to shape the outcome of species interactions in biological invasions. As invasive species alter their behaviour to accommodate to native species as predators, prey or competitors, native species analogously react to invaders. Mechanisms that drive these behavioural changes range from rapid genetic evolution to individual or social learning processes, the latter only recently being recognized as a rapid means for the spread of behavioural change. We performed a systematic literature review to gather studies reporting a change in behaviour in an invasion context. From 524 relevant papers we extracted 250 individual cases of behavioural changes. The species under study came from a broad range of vertebrate and invertebrate taxa. We analysed how quickly native species adapt to non-natives and vice versa, depending on taxonomy and mechanism of behavioural change. Additionally, we compiled cases where social learning was assumed or demonstrated, and characterized these with respect to taxonomy and life-history traits. These data were analysed with respect to the question which species possess social learning capabilities. We present results of this analysis with regard to the distribution of adaptation and learning across animal taxa with special emphasis on social learning. We discuss implications of these results, stressing the importance of learning to enable rapid behavioural changes in populations of native and non-native species.

Keywords: behavioural adaptations, eco-evolutionary experience, individual learning, rapid genetic evolution, social learning, systematic review, temporal dynamics

<footnote n="1">¹Freie Universität Berlin, Department of Biology, Chemistry, Pharmacy, Institute of Biology, Berlin, Germany</footnote>

<footnote n="2">²Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany</footnote>

<footnote n="3">³Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany</footnote>
**High variation in chemical defence and other traits as trigger in plant invasion of
*Bunias orientalis*?

Lisa Tewes<fnref n="1" />, Florian Michling<fnref n="2" />, Marcus Koch<fnref n="2" />, Caroline Müller<fnref n="1" />

Entering new habitats, invasive plant species are challenged by different environmental conditions compared to their home-range. Such changes in both biotic and abiotic conditions can cause alterations in resource allocation and thus physiological shifts in various plant traits. Consequently, beneficial adaptations in the quantity and quality of chemical and morphological defences as well as in growth and reproduction might play important roles as mechanisms underlying successful plant invasion. The Brassicaceae *Bunias orientalis* L. originates in Western Asia and Southeastern Europe but has expanded its range westwards within the Eurasian continent over the past decades, particularly conquering disturbed, nutrient-rich habitats. We compared the chemical and genetic variation as well as the influence of experimentally varied resource availability on growth and defence potential between native, truly invasive and not (yet) invasive, exotic populations. The composition of various chemical plant compounds and their relationships were investigated with a metabolomics approach using ultra high pressure liquid chromatography coupled with time-of-flight mass spectrometry (UHPLC-ToF-MS). We found a pronounced metabolic differentiation between groups of populations as well as a high chemical diversity within populations. This pattern was well mirrored in the genetic distance between the plant populations, analysed with a genome-wide fingerprinting technique (amplified fragment length polymorphisms, AFLP). Plants of these populations grown in a common garden under high and low nitrate-fertilisation regimes showed also differences in the acceptance by antagonists (herbivores and pathogens) unexperienced with *B. orientalis* as well as in growth and reproductive output traits. A strong population effect in all measured traits was observed, which was partly associated with the genetic background, but also indicated defence alterations due to the invasion process. Phenotypes highly variable in defence traits and morphology might therefore facilitate the success of range-expanding *B. orientalis* populations.

Keywords: Bunias orientalis, intracontinental range-expansion, metabolomics, chemical diversity, genetic diversity, plant-antagonist interaction, common garden experiment, nitrate allocation

<footnote n="1">¹Department of Chemical Ecology, University of Bielefeld, Bielefeld, Germany</footnote>

<footnote n="2">²Department of Biodiversity and Plant Systematics, COS, University of Heidelberg, Heidelberg, Germany</footnote>
# Breeding system, plant-pollinator networks and pollen limitation of exotic plant species

Amibeth Thompson<fnref n="1" />, Tiffany Knight<fnref n="1" />, <fnref n="2" />, <fnref n="3" />

Most angiosperms require animal pollinators, at least to some degree, to successfully reproduce. Exotic plant species must integrate themselves into resident plant-pollinator networks and attract the services of resident pollinators. Because these species are new to these ecosystems and have not co-evolved with resident pollinators, it is expected that they will receive lower pollinator service and therefore experience higher levels of pollen limitation. However, the magnitude of pollen limitation will depend on the breeding system of the exotic plant species and its dependence on animal pollination for reproduction (e.g., highly autogamous species are not expected to show pollen limitation). Further, exotic plant species with close plant relatives might more easily integrate themselves into plant-pollinator networks and receive adequate pollination. To test these ideas, we used a pollinator exclusion experiment to investigate the dependence of our focal exotic plant species on animal pollinators, and a pollen supplementation experiment to determine the extent to which our focal exotic species are pollen limited. Further, we collected a plant-pollinator network for each exotic plant species to determine the connectedness of each plant species. We found high variation amongst our focal exotic plant species in their magnitude of pollen limitation. Much of this variation could be explained by differences in their breeding system and integration into resident plant-pollinator networks. Our results indicate that pollen limitation can be an important factor limiting the reproduction of many exotic plant species, and demonstrates the importance of considering breeding systems and networks as predictors of pollen limitation.

Keywords: Breeding system, plant-pollinator networks, pollen limitation, exotic plant species

<footnote n="1">¹Institute of Biology / Geobotany and Botanical Garden, Martin-Luther-University, Halle-Wittenberg, Germany</footnote>

<footnote n="2">²Department of Community Ecology, UFZ, Helmholtz Centre for Environmental Research, Halle, Germany</footnote>

<footnote n="3">³German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany</footnote>
**Divergent levels of invasion across European woodlands**

Viktoria Wagner<fnref n="1" />, Milan Chytry<fnref n="1" />, Ilona Knollova<fnref n="1" />, Borja Jiménez-Alfaro<fnref n="1" />, Jan Pergl<fnref n="2" />, Petr Pyšek<fnref n="2" />,
<fnref n="3" />, Idoia Biurrun<fnref n="4" />, et al.

Habitat invasibility is difficult to measure in the field and often distorted locally by propagule
pressure and anthropogenic disturbance. In the last years, scientists have used vegetation survey
data to assess the level of alien plant invasion across habitats. However, these studies had a
regional scope and differed strongly in their methodological approach, especially in their habitat
classification scheme. Consequently, it was difficult to extrapolate their findings to a European
level. We used data from the European Vegetation Archive (n = 246,899 plots) to compare the
levels of alien plant invasion across EUNIS woodland habitat types. In addition to classifying
plots to a EUNIS habitat type, we assigned a status (alien, native) and origin (e.g. intra-European
taxa, extra-European taxa) for every species in a country based on multiple data sources. Data
were extensively filtered and only well-represented EUNIS types were included in the analysis.
We calculated levels of invasion as the number of alien species (neophytes; introduced after the
year of 1500) divided by the total number of species in a plot.

First results show that softwood riparian woodlands had by far the highest level of invasion (mean = 4.9%); other riparian woodlands also reached high values (> 1.3%). By comparison, coniferous woodlands tended to rank among the habitat types with the lowest levels of invasion. The most common alien species (*Impatiens parviflora*, *Robinia pseudoacacia*, *Prunus serotina*, *Quercus rubra*) had an extra-European origin and the broadest habitat niche of all alien species. Our results confirm earlier observations that woodlands with a high disturbance regime and nutrient flow are highly susceptible to alien plant invasions. Similar levels of invasion across riparian and coniferous woodlands, respectively, indicate intrinsic biotic properties that control a habitat's susceptibility to alien plant invasions.

Keywords: forests, big data, vegetation data, invasibility, level of invasion, Europe

<footnote n="1">¹Department of Botany, Masaryk University, Brno, Czech Republic</footnote>

<footnote n="2">²Institute of Botany CAS, Pruhonice, Czech Republic</footnote>

<footnote n="3">³Faculty of Science, Charles University, Prague, Czech Republic</footnote>

<footnote n="4">⁴Department of Plant Biology and Ecology, University of the Basque Country, Bilbao, Spain</footnote>
**Topic 03**
**Ecological impacts of biological invasions**

P-37

**The role of zebra mussels on bitterling oviposition**

Veronika Bartáková<fnref n="1" />,<fnref n="2" />, Martin Reichard<fnref n="1" />

The presence of non-native species can affect coevolved relationships. We examined effect of zebra mussel (*Dreissena polymorpha*) on reciprocal coevolutionary relationship between a fish, the European bitterling (*Rhodeus amarus*), and freshwater mussels (Unionidae) from two populations with different coevolutionary status (evolutionary sympatry for several generations/evolutionary naïveté). In a series of experiments under experimental, semi-natural and natural conditions, we examined two main questions: a) the effect of zebra mussel on oviposition decisions and pre-oviposition behaviour of male and female bitterling from two populations with a different level of sympatry; b) the effect of zebra mussel on reproductive success of the bitterling. We found that presence of zebra mussel near unionid siphons decreased oviposition rate into the unionids in the wild and in mesocosm. There was no effect of bitterling-zebra mussel sympatry in samples from the wild, but we found stronger decrease in bitterling use of the unionid mussels with increasing intensity of zebra mussel fouling in the mesocosm. Females oviposited less into infected unionid mussels, but did not avoid them completely. Interestingly, female bitterling sometimes oviposited directly into the zebra mussel, with a consequent failure of the eggs to develop. Behaviourally, females inspected infected mussels at the same rate as non-infected mussels, so their decision to avoid infected unionids was active.

Keywords: aquatic ecosystem, zebra mussel, fish, unionids, coevolution, host-parasite relationship, oviposition, reproductive success

<footnote n="1">¹Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic</footnote>

<footnote n="2">²Department of Botany and Zoology, Masaryk University, Brno, Czech Republic</footnote>
Humans help non-native plants break rules of species coexistence

Jane Catford<fnref n="1" />, <fnref n="2" />, <fnref n="3" />, <fnref n="4" />, Michael Bode<fnref n="2" />, David Tilman<fnref n="3" />, <fnref n="5" />

Biological invasions are considered among the chief threats to biodiversity, but whether invading species cause the loss of species from their own trophic level is hotly contested. Here we use theoretical and empirical evidence to counter the calls to end invasion ecology by showing how non-native plant invasions can disrupt mechanisms of species coexistence, leading to native plant extinctions.

By planting and dispersing non-native species in high numbers, humans can effectively increase the colonization ability of some species in a way that is independent of their ecophysiological traits. Transporting species beyond historical ranges can release species from their enemies, reducing their mortality or enabling them to reallocate resources from defense into competitive ability or reproduction. If species coexistence relies on tradeoffs among the colonization and competitive abilities of species, human-assisted alien invasions should lead to eventual declines in species diversity and coexistence.

Using simulation models, we show that species invasions, alone and with elevated disturbance, can alter community diversity in different ways and at different points in time. Short-term increases in local (alpha) diversity soon after invasion can belie long-term reductions in alpha diversity. Regional (gamma) diversity takes longer to respond to invasion, but generally declines following invasion. Impacts on community diversity are affected by the characteristics of the invaders and how they compare with characteristics of the native species. Invaders that are more competitive have greater impacts on diversity, but their impacts vary depending on whether invasion coincides with disturbance or not. Some invaders can increase alpha diversity yet still cause a decline in gamma diversity. We support our theoretical work using empirical evidence from the literature and from a six-year seed addition experiment in Minnesotan prairie.

Keywords: niche theory; extinction debt; alien plant species; ecological impact; biodiversity loss; species richness; invasion impacts; invasive species; competition-colonization tradeoffs

<footnote n="1">¹University of Southampton, Southampton, United Kingdom</footnote>

<footnote n="2">²University of Melbourne, Melbourne, Australia</footnote>

<footnote n="3">³University of Minnesota, St Paul, United States</footnote>

<footnote n="4">⁴Australian National University, Canberra, Australia</footnote>

<footnote n="5">⁵University of California, Santa Barbara, United States</footnote>
**Global patterns in extinction and threats to vertebrates by biological invasions in
islands**

Bellard Céline, et al.

*University College of London, Tourcoing, France*

Alien species have a range of impacts documented in their new environments, and there are well-documented examples of native species that have been driven extinct by aliens. However, biological invasions as drivers of biodiversity loss have recently been challenged. Some of the arguments about the impacts of alien species have been based on data on extinction, and extinction risk from the IUCN Red List. This is a dynamic resource, for which regular updates add ever greater and more accurate information on the conservation status of increasing numbers of species. Here, we revisit this resource to assess the current state of knowledge about biological invasions on islands.

We report links between vertebrates threatened by more than 200 invasive alien species from the completely revised Global Invasive Species Database. Our results show that invasive alien species are the second most common threat associated with species that have gone extinct from these taxa since AD 1500, especially on islands (>85%). New maps of the vulnerability of threatened vertebrates show that centres of IAS-threatened vertebrates are concentrated in the Americas, India, Indonesia, Australia and New Zealand, especially on islands. We found that the threat posed by invasive alien species in relation to other threats (i.e, habitat loss, pollution, overexploitation, climate change) is greater on islands than mainland areas, except in South America. Overall, there tend to be fewer threats on islands than on mainland areas. The differences in invasive threats between regions and taxa can help efficiently target invasive alien species, which is essential for achieving the Strategic Plan 2020 of the Convention on Biological Diversity. Fundamentally, we must know where species that are threatened by invasive alien species live, and the degree to which they are threatened.

Keywords: Biological invasions, IUCN Classification, islands, spatial analyses, vertebrates
**Competition for host resources between invasive (*Anodonta woodiana*) and native
freshwater mussels**

Karel Douda<fnref n="1" />, Seth Donrovich<fnref n="1" />, Vera Plechingerova<fnref n="1" />, Katerina Rylkova<fnref n="1" />, Pavel Horky<fnref n="1" />, Ondrej Slavik<fnref n="1" />, Huanzhang Liu<fnref n="2" />, Martin Reichard<fnref n="3" />

Effects of invasive alien species on host-parasite relationships are often subtle and remain
unnoticed or insufficiently quantified. We investigated *Anodonta (Sinanodonta) woodiana*, a
species of unionid bivalves with complex life cycle, which include obligatory parasitic stage
(glochidium) developing on fishes. The geographic range extensions expose *A. woodiana* to
novel communities of native fish hosts and their affiliate bivalves. It is expected that *A.
woodiana* compete with native unionids for hosts, but no direct evidence or quantification of
this process was available. Several potential mechanisms of the competition for hosts can be
expected such as direct competition by glochidia for space on hosts or via the activation of
innate host tissue responses. Most importantly, the glochidia of invasive species may trigger an
adaptive immune response by hosts, making them immunized against repeated infections after
contact with glochidia. Our study focuses on the role of priming infections by invasive glochidia
on the parasitation success of native mussel species. We experimentally tested the capacity of
European *A. anatina* to parasitize *Squalius cephalus* after previous infections with *A. woodiana*.
We compared the dynamics of initial glochidia attachment, the length of the parasitic period
and the transformation success rate of *A. anatina* glochidia among treatments. Our results
document a strong cross-resistance between the invasive and native species as the
transformation success rate of *A. anatina* was significantly reduced on primed hosts in
comparison to naïve. Such cross-resistance is expected to significantly decrease the quality of
host resources available to native mussels in natural habitats. The results provide novel insights
on the competitive mechanisms between unionid bivalves and describe novel process affecting
the invasion potential of invasive affiliate species such as *A. woodiana*.

Study was supported by the Czech Science Foundation (13-05872S).

Keywords: Sinanodonta, host-parasite relationships, Unionidae, glochidium, cross-resistance, host competition

<footnote n="1">¹Czech University of Life Sciences Prague, Department of Zoology and Fisheries, Prague, Czech Republic</footnote>

<footnote n="2">²The Key Lab of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China</footnote>

<footnote n="3">³Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czech Republic</footnote>
Prioritisation of alien plant species list for invasive plant monitoring in Latvia

Peteris Evarts-Bunders<fnref n="1" />, Gunta Evarte-Bundere<fnref n="1" />, Natalja Kavriga<fnref n="1" />, Aiva Bojare<fnref n="1" />,<fnref n="2" />, Maris Nitcis<fnref n="1" />

Invasive alien plant species cause important ecological and economic losses in Latvia, as they do worldwide. Effective management of alien plant species requires their appropriate grouping and prioritisation in national scale. Current official list of invasive organisms in Latvia includes only *Heracleum sosnowskii* Manden. (Cabinet regulation No. 468. List of invasive alien plant species). However, actual list of alien plant species in Latvia consists more than 500 taxa (Svilāns et al. 2007) with very different level of invasiveness – casual alien plants, arboreal trees with episodic escaping from cultivation, local invasions only in botanical gardens e.o. From the list of alien species of Latvia, a group of invasive plant species was selected. The highest priority is given to species that satisfy the criteria, described in European and Mediterranean Plant Protection Organization (EPPO) methodology of prioritization process for invasive alien plants (Anonymous 2012) as well as supplemented with some specialised criteria, selected for local conditions and requirements of invasive plant monitoring: 1) negative impact on EU habitats, 2) data not obtained in other monitoring programmes in Latvia, 3) plant reproduces effectively in wild nature, 4) massive weed of agriculture, 5) genetical erosion of any native species, 6) invasive species in neighbouring countries, 7) species assesment has been carried out in Latvia (actual number of localities e.o), 8) widely cultivated plant species, 9) invasion not subsided for concrete species.

Based on criteria adopted, 35 invasive plant species, appropriate for invasive plant monitoring was identified. – *Acer negundo* L., *Amelanchier spicata* (Lam.) K. Koch., *Aster salignus* Willd., *Cotoneaster lucidus* Schltdl., *Echinocystis lobata* (Michx.) Torr. et A. Gray, *Impatiens glandulifera* Royle, *Impatiens parviflora* DC, *Lupinus polyphyllos* Lindl., *Rosa rugosa* Thunb., *Sambucus racemosa* L., *Solidago canadensis* L., *Solidago gigantea* Aiton, *Sorbaria sorbifolia* (L.) A. Braun, *Reynoutria japonica* Houtt. and *Reynoutria sachalinensis* (F. Schmidt) Nakai shows doubtless invasiveness in national scale, to agree with at least seven above mentioned criteria and were decided as priority group for invasive plant monitoring.

References

* Anonymous (2012). EPPO prioritization process for invasive alien plants. Bulletin OEPP/Bulletin, 42 (3): 463-474.

* Svilāns A., Celmiņš A., Āboliņa A., Teļnovs D., Vimba E., Gavrilova G., Strāķe S., Pilāts V. (2007) List of alien species in Latvia. biodiv.daba.gov.lv/cooperation/invaz/i-netam_ivazivie.xls

Keywords: Invasive plants, monitoring, prioritisation, Latvia

<footnote n="1">¹Institute of Life sciences and Technology, Daugavpils University, Daugavpils, Latvia</footnote>

<footnote n="2">²National Botanic garden, Salaspils, Latvia</footnote>
*Impatiens parviflora* affects native vegetation in oak-hornbeam forests

Anna Florianová<fnref n="1" />, <fnref n="2" />, Zuzana Münzbergová<fnref n="1" />, <fnref n="2" />

*Impatiens parviflora* is one of the most widespread invasive plant species in Central Europe. Nevertheless, the mechanisms of its invasion are still poorly understood. In this study we attempt to understand the impact of this species on native vegetation.

The impact of *Impatiens* on native vegetation was studied using removal experiment on permanent plots in oak-hornbeam forests in central Bohemia, Czech Republic. Ten pairs of plots were established in invaded vegetation, one plot in each pair stayed invaded and the other served as removal plot and all *Impatiens* individuals were repeatedly removed from the plot. Species composition in 4 subsequent years was recorded in the plots. Species response to *Impatiens* removal was correlated to plant traits to reveal trait characteristics of species suppressed or supported by the invasion.

Significant increase in both numbers and cover of native species was observed in removal plots in comparison with control plots during the experiment, with the greatest change in first two years after invader removal. Species composition also significantly differed between control and removal plots. Species with high affinity to removal plots, i.e. species that are most restricted by *Impatiens* invasion, were mostly species with small releasing height and early start of flowering.

Our results indicate that *Impatiens parviflora* has negative impact on native vegetation but that the vegetation can recover within few years after the invader removal. Due to its extensive distribution and high turnover, removal of the species from larger plots is, however, not realistic in practice.

Keywords: Impatiens parviflora, small balsam, impact, removal experiment

<footnote n="1">¹Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic</footnote>

<footnote n="2">²Institute of Botany, Czech Academy of Sciences, Pruhonice, Czech Republic</footnote>
How the burrowing activity of the North American crayfish *Procambarus clarkii*
alters the seepage process in river levees

Phillip Haubrock<fnref n="1" />,<fnref n="2" />, Alberto Inghilesi<fnref n="1" />,<fnref n="2" />, Giuseppe Mazza<fnref n="2" />, Michele Bendoni<fnref n="3" />, Enio Paris<fnref n="3" />, Luca Solari<fnref n="3" />, Elena Tricarico<fnref n="2" />

The North American crayfish *Procambarus clarkii* is an invasive species mostly introduced for commercial purposes. It causes declines in biodiversity and radical habitat change while showing a high dispersal probability and reproduction rate enabling it to rapidly spread within the invaded areas. Several scientific efforts studied the effects (e.g. increased turbidity, vegetation loss, food web structure disruption) this species has on recipient ecosystems. Only recently, scientific focus was given to damages caused by *P. clarkii* on levees of rice fields, irrigation ditches and small rivers. Indeed, burrowing activity can enhance the seepage process, affecting the integrity of the structure.

In order to understand the impact of burrowing activity on the seepage process, since 2015 we have conducted experiments in artificial environments at the Hydraulic Laboratory of the Department of Civil and Environmental Engineering of the University of Florence, using a small-scale model of a levee built inside a tank. The model was mostly composed by silt, clay and sand (the favoured soil for the burrowing activity of the species) and equipped with microtensiometer to measure the phreatic line within the levee. A series of several experiments was carried out, and for each replicate, water level was kept constant on a side (riverside) of the levee and the other side was initially left dry (landside). Two couples of crayfish (composed of one adult male and one adult female), were transferred into the wetted side to observe their burrowing activity for four days under natural light-dark cycles. The animals were fed daily to limit the probability of aggression and cannibalism among specimens. Animals were removed from the tank at the end of all experiments and burrows were filled with polyurethane foam. After one day, the mold of consolidated foam was removed from the levee to measure the volume and analyse the shape of the burrows.

In general, animals started digging immediately after their insertion, particularly in the summer,
altering the water clarity and increasing the suspended solids. Burrows resulted to be irregular,
composed by more than one tunnel and sometimes with a chamber at the end. The ratio of the
excavated volume to the initial volume of the physical model ranged from 1 to 18% among the
experiments. The presence of burrows in the levee favours the raise of the phreatic line,
increasing the possibility of its emergence on the landside, and potentially affecting the integrity
of the structure.

Keywords: invasive species, impact, burrowing

<footnote n="1">¹NEMO, Nature and Environment Management Operators s.r.l, Florence, Italy</footnote>

<footnote n="2">²Department of Biology, University of Florence, Florence, Italy</footnote>

<footnote n="3">³DICEA, Department of Civil and Environmental Engineering; University of Florence, Florence, Italy</footnote>
**Effect of an alien fish, the racer goby (Babka gymnotrachelus), on the occurrence of the European bullhead (Cottus gobio)**

Tomasz Kakareko¹, Jarosław Kobak², Joanna Grabowska³, Łukasz Jermacz², Dagmara Błońska³, Mirosław Przybylski³, Małgorzata Poznańska²

¹Nicolaus Copernicus University, Faculty of Biology and Environmental Protection, Department of Hydrobiology, Torun, Poland

²Nicolaus Copernicus University, Faculty of Biology and Environmental Protection, Department of Invertebrate Zoology, Torun, Poland

³University of Lodz, Faculty of Biology and Environmental Protection, Department of Ecology and Vertebrate Zoology, Lodz, Poland

Racer goby is a fish of Ponto-Caspian origin, currently spreading in Europe. It has been supposed to cause harmful effects on native bullhead populations. We conducted laboratory and field studies to assess the mechanisms of competitive interactions between the species assuming that competitive resources are shelters and food. To check the outcome of the competition for a shelter, we measured behavioural interactions between 2 specimens (one- or mixed-species treatments) in a tank with 1 shelter (PVC half-tube), with the following factors included: fish size (2 size classes), light (day, night), season (spring, autumn), water flow velocity (0, 10 and 30 cm s-1). To check the result of competition for food, we tested fish using the same design, but with a feeder instead of a shelter as a limited resource and including only one factor: light (day, night). We analysed the following variables: aggressive interactions (attacks, threatening acts), time spent by the fish in a shelter/feeding area, feeding time, frequency of visits and the species identity of the first visitor in the shelter/feeder in each interspecific pair. In the field, we assessed niche overlap and relationships of specimen counts among 4 fish groups (2 species x 2 size classes) on various bottom substrata across the entire width of the river bed in a tributary of the Vistula River. We found that the racer goby is more aggressive than European bullhead of similar size. That is why the gobies displace bullheads from shelters and feeding grounds. Competition for a shelter is more intensive during spawning season (spring) when both species use similar habitats for spawning and parental care of eggs. This could have harmful consequences for bullhead populations. Moreover, the racer goby has appeared as a highly adaptive competitor, being able to win the competition for shelters even when exposed to water flow velocity of 30 cm s-1. This means that in rivers colonized by the racer goby, European bullheads are likely to be limited to areas avoided by the alien species, such as fast flowing river stretches with stony bottom.

The research was supported by a Grant of the Polish Ministry of Science and Higher Education No. N N304 371539.

Keywords: Ponto-Caspian gobiids, Interspecific competition, Alien species impact, Aggressive behaviour
# CIMPAL: Mapping the cumulative impact of alien species on marine ecosystems

Stelios Katsanevakis<fnref n="1" />, Heliana Teixeira<fnref n="2" />, Fernando Tempera<fnref n="2" />, Evangelos Boltsis<fnref n="1" />

CIMPAL (Cumulative IMPacts of invasive ALien species) is a standardized, quantitative method developed to assess and map cumulative impacts of invasive alien species on marine ecosystems. According to this model, cumulative impact scores are estimated on the basis of the distributions of invasive species and ecosystems, and both the reported magnitude of ecological impacts and the strength of such evidence. We applied CIMPAL in two case studies: (1) in the entire Mediterranean Sea, using presence/absence data for the distribution of species and habitats in 10x10 km cells, and (2) in the marine NATURA-2000 sites of Greece, using detailed habitat maps and presence data of alien species. In both cases, data on the presence/absence of invasive marine alien species were retrieved from the European Alien Species Information Network (EASIN). In the Mediterranean case study, the CIMPAL index showed strong spatial heterogeneity and spatial patterns greatly varied depending on the pathway of initial introduction of the invasive species. In the Greek case study, the spatial patterns of impact were analyzed by Generalized Additive Models of the CIMPAL index in relation to the area of each site, its longitude and latitude. The CIMPAL index increased due to the increased richness of both alien species and habitats with area. The index increased with latitude in accordance to the higher alien species richness at higher latitudes, when considering only benthic habitats. No significant pattern in relation to longitude was revealed. In both cases, the analyses allowed the identification of hotspots of highly impacted areas, and prioritization of sites, pathways, and species for management actions. The application of the CIMPAL index in both cases provided a baseline that can be built upon with future improved information (such as estimates of the alien species abundance at each site instead of presence/absence data). Such analysis and mapping of impacts is urgently requested by policy makers and managers, e.g. for the implementation of the EU Marine Strategy Framework Directive.

Keywords: cumulative impacts, indicators, prioritization, Mediterranean, Greece

<footnote n="1">¹University of the Aegean, Department of Marine Sciences, Mytilene, Greece</footnote>

<footnote n="2">²Joint Research Centre, Institute for Environment and Sustainability, Water Resources Unit, Ispra, Italy</footnote>
# The competition between invasive and native plants for pollinators

Viktor Khvir

Zoology department, Biology Faculty, Belarusian State University, Minsk, Belarus, Minsk, Belarus

Invasive plant species are making changes not only in plant communities during penetrating in new areas. They are also capable to change the composition of pollinators' communities of native plants by attracting anthophilous insects because of more resources nectar and pollen. In this case, native flora plants may suffer from a pollen limitation and even be not enough pollination. Thus, invasive species can create competitive pressure on native species for pollinators.

We studied the effects of invasive hogweed *Heracleum sosnovskyi* Manden to the composition of the pollinators' communities of native plants of the same family Apiaceae in Belarus. As such, we have chosen the species that grow in similar areas: goutweed *Aegopodium podagraria* L, wild carrot *Daucus carota* L, beaked parsley *Anthriscus sylvestris* (L.) Hoffm. and angelica officinalis *Angelica archangelica* L. We defined the taxonomic structure of these pollinators communities of umbrella plants. Then we estimated the intensity of the competition for pollinators between plants using Shener index of overlapping of the spectra. The results showed that the highest similarity of taxonomic structure of pollinators' communities observed in pair cow parsnip Sosnowski and wild carrot (0.622). Also high index indicators were typical for pairs Sosnovsky hogweed and goutweed (0.581) and Sosnovsky hogweed and beaked parsley (0.516). Namely these plants species under joint growing are most likely remain with lack of pollen. This is primarily due to pollen limitation which can lose during process of transferring by pollinators to flowers of another plant species. *Heracleum sosnowskyi* as large plant with big inflorescences is the source of a large amount of nectar and pollen and it more successful attracts insect pollinators than others umbellifers.

Thus, the overlapping of the spectra of taxonomic structure of pollinators communities indicates the interspecific competition, sometimes very strong. As a result, native plants are at risk of extinction or enhancement of directional selection pressure to restrict certain groups of pollinators or they need to change the time of flowering to avoid competition with more potent invasive species.

Keywords: insect pollinators, Heracleum sosnovskyi, competition for pollinators
**Genetic diversity of *Impatiens parviflora* DC. populations in relation to abiotic and biotic environment**

Rasa Janulioniene<fnref n="1" />, Lina Jociene<fnref n="1" />, Vitas Marozas<fnref n="2" />, Tomas Rekasius<fnref n="3" />, Algimantas Paulauskas<fnref n="1" />,
Eugenija Kupcinskiene<fnref n="1" />

*Impatiens parviflora* has emerged in Europe in the early 1800s and areas occupied by this species are still increasing. Within former century wide studies have been performed concerning phytosociology and physiology of *I. parviflora* growing in Central and Western Europe. In a contrast to the other widely spread aliens, like *Heracleum* spp., *Fallopia* spp. or *Impatiens glandulifera*, *Impatiens parviflora* was already forgotten, when molecular investigation of invaders started and till now remains among the least genetically examined aliens. Data concerning routes and consequences of the spread of this species in more Eastern and Northern parts of the continent are extremely poor.

Present study is aimed at evaluation of molecular diversity of *I. parviflora* populations growing in Eastern Baltic with special stress for relations between genetic diversity and abiotic and biotic environment. Twenty-one populations of *I. parviflora* were selected in the way to cover all the territory of Lithuania. When selecting populations for sampling, attention was paid to reflect habitat diversity, including both urban and semi-natural sites. Dominant DNA markers were chosen for examination of populations applying Bayesian Structure analysis. In addition, associated species, their projection coverage were recorded and Ellenberg indicatory values (EIV) were calculated. For each site several environment features were recorded and populations were grouped according to each parameter into 2-4 clusters: water source and its proximity; traffic intensity / road vicinity, proximity to human buildings. Nei's genetic distances among populations differed up to 4 times. Molecular diversity among populations was much higher than intrapopulation diversity. The Bayesian analysis of over 300 individuals of *I. parviflora* revealed, that a simulation equilibrium (likelihood of K's) provided by the genomic structure for the model was reached at K = 13 (in case of Randomly amplyfied polymorphic DNA markers) and K = 11 (in case of inter-simple sequence repeat markers of DNA). The most frequent neighbors' of *I. parviflora* were following species: *Urtica dioica*, *Aegopodium podagraria*, *Chelidonium majus*, *Galium aparine*, *Anthriscus sylvestris*, *Alliaria petiolata*, *Heracleum sibiricum*, *Geum urbanum*, *Impatiens noli-tangere*. EIV of neighboring species showed prevalence of neutral and rich in nitrogen soils. Interrelations between population genetic parameters and their environment features will be discussed.

Study was funded by Lithuania Science Council, Project No. LEK-07/2012; SIT-02/2015

Keywords: alien plants, invasive species, Ellenberg indicatory values, Balsaminaceae, small balsam, molecular variance, dominant markers, ISSR, RAPD

<footnote n="1">¹Department of Biology, Vytautas Magnus University, Kaunas, Lithuania</footnote>

<footnote n="2">²Institute of Environment and Ecology, Aleksandras Stulginskis University, Kaunas region, Lithuania</footnote>

<footnote n="3">³Department of Mathematical Statistics, Vilnius Gediminas Technical University, Vilnius, Lithuania</footnote>
*Acacia dealbata* impacts in Mediterranean areas worldwide: phylogenetic loss in
novel plant communities' assemblages.

Lorenzo Lazzaro<fnref n="1" />, Paula Lorenzo<fnref n="2" />, Andrea Coppi<fnref n="1" />, Claudia Giuliani<fnref n="3" />, Luís González<fnref n="4" />, Anibal Pauchard<fnref n="5" />, Andrés Fuentes-Ramirez<fnref n="6" />, Bruno Foggi<fnref n="1" />

The Australian tree *Acacia dealbata* Link (Mimosaceae - Fabaceae) is one of major invaders in the Mediterranean ecosystems of Europe, Africa and America, where it forms dense monospecific patches severely affecting native plant communities. The effects of this species on the native biodiversity are well-known and are linked to a reduction in species richness and diversity, which generates poorer and less-diverse novel communities compared to native ones. To this regard, the effect of this species on the phylogenetic structure of invaded communities are poorly known and investigated.

The present study evaluates the impacts of *A. dealbata* on phylogenetic diversity of invaded
communities and the phylogenetic structure of these novel plant communities after the invasion
by *A. dealbata*. Toward these aims we exploited data from samplings conducted in
Mediterranean scrublands located in the limit of the Mediterranean area (Northwest of Spain),
in the middle of the bioclimatic region in Europe (Elba Island), and in Mediterranean climate
areas from Chile. Three levels of invasion statuses were differentiated according to the gradient
generated by *A. dealbata* during the invasion process (invaded, transitional and non-invaded
sites) in each studied community. We firstly studied the variation in taxa richness and diversity.
Subsequently, we built a phylogenetic tree adopting the AGPIII phylogenetic information.
Finally, we studied and compared the variation in phylogenetic distance (PD) and mean
phylogenetic distance (MPD) among different invaded statuses and biogeographic areas. Data
analyses confirm that invasion by *A. dealbata* generally causes a strong decrease in the richness
and diversity of understory plant species following the ranking invaded > transitional > non-
invaded sites, with effects comparable in the three invaded ranges. The phylogenetic data
suggest that the loss in native species is linked to a severe phylogenetic loss in the invaded
communities. Indeed, PD was also found to strongly decrease following the above-mentioned
trend. On the other hand, MPD showed still the lowest values in invaded sites, but with more
variation among biogeographic areas for the relationship between transitional and non-invadeds
sites.

Keywords: Phylogenetic distance, Mean Phylogenetic Distance, species richness, Phylogenetic Diversity

<footnote n="1">¹Department of Biology, University of Florence, via G. La Pira 4, I-50121, Florence, Italy</footnote>

<footnote n="2">²Centro de Ecologia Funcional, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3000-456, Coimbra, Portugal</footnote>

<footnote n="3">³Department of Pharmaceutical Sciences, University of Milan, via Mangiagalli 25, I-20133, Milan, Italy</footnote>

<footnote n="4">⁴Departamento de Bioloxía e Ciencia do Solo. Facultade de Bioloxía. Universidade de Vigo. E-36310, Vigo, Spain</footnote>

<footnote n="5">⁵Laboratorio de Invasiones Biológicas (LIB), Facultad de Ciencias Forestales, Universidad de Concepción. Casilla 160-C, Concepción, Chile</footnote>

<footnote n="6">⁶Laboratorio de Biometría, Departamento de Ciencias Forestales, Universidad de La Frontera, Casilla 54-D, Temuco, Chile</footnote>
# Freshwater crayfish invasions in South Africa

Ana Nunes<fnref n="1" />, <fnref n="2" />, <fnref n="3" />, Tsungai Zengeya<fnref n="4" />, G. John Measey<fnref n="1" />, Olaf Weyl<fnref n="2" />

No indigenous freshwater crayfish species exist in continental Africa, but several North American and Australian species have been introduced since the 1970s. In South Africa, four species of alien crayfish are listed under the National List of Invasive Freshwater Invertebrate Species: the Danube crayfish (*Astacus leptodactylus*), the common yabby (*Cherax destructor*), the marron (*Cherax tenuimanus*) and the Australian redclaw crayfish (*Cherax quadricarinatus*). It is known that *Cherax quadricarinatus* was introduced into South Africa via Swaziland around 2000, after escaping from the Sand River Dam, where it was farmed, due to a large flooding event. However, no detailed information exists on the distribution, abundance and impacts of populations of this or other potential crayfish species in South Africa.

In this study, we start by presenting an overall view of the current knowledge of crayfish invasions in South Africa. Then, we focus on the Australian redclaw crayfish (*C. quadricarinatus*), the only species that appears to be widely distributed in the country. For this, we performed sampling surveys in several regions in South Africa and Swaziland, in which collapsible baited crayfish traps were set along water bodies, left overnight, and checked the following morning for crayfish presence. All the individuals were sexed, weighed and measured. We report on the presence of established populations of *C. quadricarinatus* in rivers and irrigation dams in Mpumalanga and several areas in Swaziland. We also look at crayfish abundances, biomass and sex ratio.

We discuss the implications of these results regarding the potential presence of additional crayfish populations in South Africa, and the possible impact of *C. quadricarinatus* on native biota and natural habitats. This information is essential to support the development and implementation of adequate action plans for the management and control of invasive crayfish species in South Africa.

Keywords: crayfish, Africa, status, populations

<footnote n="1">¹Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa</footnote>

<footnote n="2">²South African Institute for Aquatic Biodiversity, Grahamstown, South Africa</footnote>

<footnote n="3">³Invasive Species Programme, South African National Biodiversity Institute, Cape Town, South Africa</footnote>

<footnote n="4">⁴South African National Biodiversity Institute, Pretoria, South Africa</footnote>
# Feral cat (*Felis silvestris catus*) predation at a biodiversity hotspot scale: the case of the New Caledonian Archipelago

Pauline Palmas<fnref n="1" />, <fnref n="2" />, Elsa Bonnaud<fnref n="2" />, Edouard Bourguet<fnref n="1" />, Leo Debar<fnref n="1" />, Hervé Jourdan<fnref n="1" />, Matthias Lee<fnref n="1" />, Mathieu Mathivet<fnref n="1" />, Hélène De Méringo<fnref n="3" />, Alexandre Millon<fnref n="3" />, Frédéric Rigault<fnref n="1" />, Eric Vidal<fnref n="1" />

Biological invasions are one of the main threats to biodiversity, especially on islands where introduced species are the first cause of biodiversity loss. Alien mammalian predators are responsible for numerous island species extinctions worldwide, and feral cats (*Felis silvestris catus*) are among the most successful and damaging invaders due to their generalist predatory behaviour and their high reproductive and survival successes. Although a strong feral cat impact was suspected on the New Caledonian

archipelago (south Pacific), no previous study and cat predatory evaluation had been conducted.

<figure><img src="image_15.png" /></figure>

This study aims to evaluate feral cat impact on this biodiversity hotspot that shows exceptional endemic rates, partly due to its geographical isolation and specific ultramafic soils. Feral cat invaded almost all the islands of this archipelago from seashore habitats to highest altitude forest (1628m), most of these habitats harbouring unique species assemblages. In order to study cat predation, we calculated, through scat analysis, its predatory consumption of every taxonomic prey group with a focus on endemic species. We collected, and then macroscopically analysed, more than 6000 cat scats found upon 16 sites representing the different habitats of this archipelago. This sampling was conducted across 4 to 6 sampling sessions per site over 2 years. At the archipelago's scale, cats mainly prey upon introduced rats (Frequency of Occurrence (FO): 77%). This staple resource could boost cat population dynamics and subsequently cat impact on native preys. In addition, cats strongly prey upon reptiles (FO: 42%), flying foxes (FO: up to 30% in some humid forests), most of them being endemic, and petrels (FO: up to 25% in some mountain areas). Feral cats at least prey upon 17 threatened species corresponding 4 species listed by the IUCN Red List as "critically", 7 endangered and 6 vulnerable. This species list includes 3 flying foxes, 2 birds, 1 gecko and 11 skinks, most of them being exclusively present inside the mosaic maquis/humid forest habitat that covers a major part of the main island. This study also confirms the strong variations in cat diet according to habitats and highlights original cat predation patterns on alien and endemic species. This study provides recommendations to prioritize management and conservation strategies in a biogeographic region where such actions are urgently needed to preserve island biodiversity and ecosystems.

Keywords: Felis silvestris catus, invasive predator, trophic behaviour, diet, threatened species, islands

<footnote n="1">¹Institut méditerranéen de biodiversité et d'Écologie marine et continentale (IMBE), Aix-Marseille Université, UMR AMU/CNRS/IRD/UAPV, Centre IRD de Nouméa, BPA5, 98848 Nouméa cedex, Nouvelle-Calédonie, Nouméa, New Caledonia</footnote>

<footnote n="2">²Unité Écologie, systématique et évolution, Equipe Écologie des populations et des communautés, Université Paris-Sud 11, UMR 8079/UPS/CNRS/AgroParisTech, Bât. 362, 91405 Orsay cedex, France, Orsay, France</footnote>

<footnote n="3">³Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Aix-Marseille Université, UMR CNRS-IRD-UAPV, Europôle de l'Arbois, BP 80, 13545, Aix-en-Provence, France, Aix-en-Provence, France</footnote>
**Friend or enemy? Chemical recognition and reciprocal responses among native and alien amphipods**

Michał Rachalewski<fnref n="1" />, Jarosław Kobak<fnref n="2" />, Łukasz Jermacz<fnref n="2" />, Karolina Bącela-Spychalska<fnref n="1" />

In aquatic environment, intra- and inter specific communication is often associated with
infochemicals used e.g. in reproductive behaviour, early-warning systems for predator
detection, identification of predation pressure or food detection. The ability to respond
adequately to environmental cues is crucial for invasive species, facing new communities with
unknown predators, prey and competitors. On the other hand, they can also encounter other
aliens from the same native region, and the capability of recognizing them is likely to increase
their fitness in new locations. In our experiments we focused on amphipods, which are
considered as a perfect model for ecological and behavioural studies, due to their high
environmental impact and gregariousness. We studied intra- and interspecific recognition of
chemical stimuli released by three invasive freshwater gammarids originating from Ponto-
Caspian region (Dikerogammarus villosus, Dikerogammarus haemobaphes and
Pontogammarus robustoides) and indigenous European Gammarus fossarum. The ability of
chemical recognition among these species was checked in all pairwise combinations.

We conducted our experiments in a y-maze tank with gravitational inflow of water (0.5 L min⁻<fnref n="1" />) to the y-arms from two separate source tanks with appropriate signals (scent of living animals or their alarm cues) or control water. Scent of living animals was obtained as the water from a 200-1 tank with 300-400 individuals incubated for at least 24 h. Alarm cues were obtained by manual crushing of c.a. 10 gammarids and adding their exudate to the source tank. We analysed three variables: time spent in a given y-arm, number of entrances to the arms and activity of animals.

All the tested amphipod species responded to the applied signals. Only *D. villosus* was attracted to the alarm cues and living heterospecifics, but not to living conspecifics. *P. robustoides*, *D. haemobaphes* and naive *G. fossarum* avoided the scent of the strongest competitor and predator, *D. villosus*, and/or decreased their activity in its presence. Interestingly, the presence of *D. haemobaphes* reduced activity of the other species.

Our results showed that the behaviour of *D. villosus* was distinctly different from the other
species, as it was attracted to most of the applied scents. This confirms its status of a very strong
competitor and predator, which interprets various scents as food cues and is perceived as a threat
by other gammarids.

The study was supported by National Science Centre grants 2011/03/D/NZ8/03012 and 2012/05/B/NZ8/00479.

Keywords: amphipoda, Ponto-Caspian species, communication, alarm cue

<footnote n="1">¹Department of Invertebrate Zoology and Hydrobiology, University of Lodz, Lodz, Poland</footnote>

<footnote n="2">²Department of Invertebrate Zoology, Nicolaus Copernicus University, Torun, Poland</footnote>
# Species invasions as perturbations to mutualistic interactions: complementary theory and empirical work

Laura Russo¹, Jane Memmott², Yvonne Buckley³, Katriona Shea¹

¹Penn State University, University Park, United States

²University of Bristol, Bristol, United Kingdom

³Trinity College, Dublin, Ireland

When species invade outside their native ranges, they will usually interact with new species and form novel communities. Because they are integrating into existing networks of interactions, invasive species can act as perturbations to a resident community.

We use complementary theoretical and empirical approaches to generate and test predictions about how invaders impact plant-pollinator communities.

First, we demonstrate experimentally that the invasion of an invasive thistle (*Carduus acanthoides*) can significantly increase the species richness and abundance of a wild bee community.

Then we apply network theoretic models to the empirical community affected by invasive Himalayan Balsam (*Impatiens glandulifera*) to generate theoretical predictions about how multiple aspects of mutualistic network structure will change in response to the addition of a novel species.

The predictions suggest that the impact of the perturbation on network structure increases with the generality of the invader. This theoretical-empirical approach can be used to anticipate the impact of species that are currently changing in distribution and provides testable hypotheses for how invasive species will change resident networks of interactions.

Keywords: mutualism, network theory, invasive species, plant-pollinator, bees, Carduus acanthoides, Impatiens glandulifera
# Potentially invasive birds in Ukraine

Valentyn Serebryakov, Valentyn Serebryakov, Vitalii Kazannyk

Biol. Dept., Taras Shevchenko National University in Kiev, Kiev, Ukraine

During the last decades, rare cases of observation of non-common species of birds became known on territory of Ukraine. The numerous cases, related to the parrots (Psittaciformes), Estrildid finches (Estrildidae), are known for today, which often escape from captivity, however form some local populations in spite of cool climate for them. However, there is another group of species that feels themselves comfortably in the climatic terms of Ukraine, but geographically related to North and South America, and also with Australia and different regions of Asia. Such species as Muscovy duck (*Cairina moschata*), Mandarin duck (*Aix galericulata*), Wood duck or Carolina duck (*Aix sponsa*), Black swan (*Cygnus atratus*), Snow goose (*Chen caerulescens*), Bar-headed goose (*Anser indicus*), Canada goose (*Branta canadensis*), Chiloé wigeon or Southern wigeon (*Anas sibilatrix*) and some other often escape from private and public zoos. Three last species are able to fly to Ukraine from established in Western Europe populations. Most of them feel themselves comfortably on this territory (even in cities), and at formation of viable populations these birds can directly or/and indirectly influence on local ecosystems, make an impact on vegetable cover (including agricultural one), conduct hybridization with local species, and also forcing out local species of their common habitats. Except it, these species can be a potential danger for aviation flights and dangerous for domestic animals and human health. Therefore, it is necessary to conduct the regular monitoring of reservoirs and other natural habitats in order to reduce such potential invasive dangerous bird species in time, work out steps and plan management activities for control their numbers.

Keywords: invasions, Ukraine
# Diet composition and trophic interactions between round goby and native benthophagous fish in the coastal waters of SE Baltic Sea

Artūras Skabeikis, Jūratė Lesutienė

Marine Science and Technology Center, Klaipeda University, LT-92294, Klaipeda, Lithuania

The round goby (*Neogobius melanostomus*) is a very successful invasive fish species, which was unintentionally introduced to the Baltic Sea in 1990 and since then became a key component of benthic ichthyofauna in invaded areas. As aggressive opportunistic predator, round goby easily adapts to feed on various different preys and usually outcompetes native fish in the food competition.

To evaluate potential negative effect of round goby to native benthivorous fish, feeding patterns, including diet composition, feeding activity and feeding niche overlap of differently sized round gobies, flounders (*Platichthys flesus*) and vimbas (*Vimba vimba*) were determined. Sampling took place in the SE Baltic Sea, Lithuanian coastal waters during July-September 2015 using multi mesh (14-60 mm) gill nets. Dietary analysis was performed in 147 round gobies, 205 flounders and 72 vimbas.

The smallest specimens of round goby (60-120 mm) and flounder (100-120 mm) preyed mainly on polychaetes, while larger individuals of both species preferred bivalve mollusks *Macoma balthica*, *Mya arenaria* and *Cerastoderma lamarcki*. The diet of vimba was composed of equal proportions of bivalves, brown shrimps *Crangon crangon*, polychaetes and macroalgae. Round goby fed more actively than vimba, but its feeding activity was lower compared to flounder. Round goby was the most efficient benthic feeder (19.7% of non-feeding individuals) followed by flounder (37.1%) and vimba (44.4%). Feeding niche overlap between differently sized round gobies, flounders and vimbas was biologically significant, indicating high rates of food competition among native and invasive bottom dwelling fish. Invasion of the round goby did not pose detrimental effect to prey populations, because biomass of soft bottom zoobenthos did not decrease after the round goby introduction.

Keywords: round goby, benthophagous fish, food competition
**Size matters: predation of fish eggs and larvae by native and invasive amphipods**

Nigel Taylor, Alison Dunn

School of Biology, University of Leeds, Leeds, United Kingdom

Invasive predators can have dramatic impacts on invaded communities, especially in fresh
waters. Invasion by the killer shrimp *Dikerogammarus villosus* is often followed by extreme
declines in resident macroinvertebrate populations, thought to be driven by predation. Since *D.
villosus* has been observed to consume fish eggs and larvae, there are concerns over similar
impacts on fish populations – but these remain poorly quantified.

In laboratory microcosms, we compared the predatory impact of invasive *D. villosus* and a native analogue *Gammarus pulex* on the eggs and larvae of two representative fish species: ghost carp (*Cyprinus* sp.) and brown trout (*Salmo trutta*). We used size-matched amphipods as well as larger *D. villosus* to reflect natural sizes. We quantified predation of fish eggs or larvae presented (a) at a range of densities (to quantify functional responses) and (b) at fixed densities in the presence of alternative foods (allowing assessment of electivity).

Carp eggs and larvae were readily killed and consumed by all amphipod groups. Large *D. villosus* had functional responses 1.6 to 2.0 times higher than the smaller amphipods, whose maximum feeding rates did not differ. In electivity experiments involving carp eggs, large *D. villosus* consumed more food overall and more eggs than the smaller amphipods. Intermediate *D. villosus* also consumed more eggs than *G. pulex*. In electivity experiments with carp larvae, consumption did not differ between amphipod groups.

Large *D. villosus* were much more likely to prey upon trout larvae (74% of individuals) than
intermediate *D. villosus* (29%), in turn more likely to kill trout larvae than *G. pulex* (6%).
However, these predators rarely killed more than one larva. Trout eggs were almost completely
invulnerable to amphipod predation: only 2% of amphipods killed any eggs.

In sum, our data suggest *D. villosus* will have a greater predatory impact on fish populations
than *G. pulex*, primarily due to its larger size. *D. villosus* could have a *per capita* impact on
coarse fish around 1.6 times that of *G. pulex*, and an unprecedented *per capita* impact on
salmonid larvae. Even a small increase in predatory pressure following *D. villosus* invasion
could negatively affect recruitment into biologically or commercially important fish populations
(Houde 2002).

**Reference**

Houde, E.D. (2002) Mortality. In Fuiman, L.A. & Werner, R.G. (eds) *Fishery Science: The Unique Contributions of Early Life Stages*, pp 64–87. Blackwell Science.

Keywords: Dikerogammarus, predatory functional response, invasive species, impact, body size
# Impact assessment of alien plant species in forest ecosystems of Poland - methodological and practical remarks

Wladyslaw Danielewicz<fnref n="1" />, Barbara Tokarska-Guzik<fnref n="2" />, Zygmunt Dajdok<fnref n="3" />

The need for the unification of evaluation criteria for invasive species, or alien species in general, has been reported for a long time. A publication by Blackburn and co-authors (2014) became a new impulse to further testing and discussion.

The methodological concept was tested on the group of 176 alien plant species recorded as permanently established in forest ecosystems of Poland. Every species was subjected to an evaluation according to the criteria determined by Blackburn et al. (2014). The following scope of data collected for the species examined constituted the basis of the assessment: the most frequent pathway of introduction; the number of localities; dynamic tendencies; the degree of participation in plant communities; impact; hampering of forest management.

From the alien plant species identified from the forests of Poland, the taxa penetrating the best preserved forest communities deserve the greatest attention - over 20 species from the total analysed were ranked in this group. Considering forest management, an important group of species are those which can hamper forest restocking. About 30 (over 17%) of the alien species occurring in forests of Poland belong to this group. One third of them require the implementation of special treatments before undertaking work associated with planting trees, which causes measurable losses in forest management.

In determining the kind and the level of impact of species on ecosystems the greatest problem constitutes the lack of accurate data obtained as the result of long-term studies. This lack has resulted in the identification of direct competition as being a primary impact for most of the species investigated. Only a few species were identified as having an influence through hybridization, toxicity, bio-fouling or chemical impacts on ecosystems. The lack of long-term studies in relation to the reaction of ecosystems to the presence of alien species also constituted a problem in determining the general impact category. Therefore, as many as one third of all analysed species were placed in a “Data Deficient” category. Moreover, in the case of the highest impact categories “Major” and “Massive”, determining the reversibility of changes in the ecosystem caused by alien species was a problem, and therefore only in a few cases was it possible to rank the species in the highest category.

Blackburn TM et al (2014). A Unified Classification of Alien Species Based on the Magnitude of their Environmental Impacts. PLoS Biology 12(5): e1001850.
doi:10.1371/journal.pbio.1001850.

Keywords: environmental impact, prioritization, invasive alien species, non-native species

<footnote n="1">¹Department of Forest Botany, Poznan University of Life Sciences, Poznan, Poland</footnote>

<footnote n="2">²Department of Botany and Nature Protection, University of Silesia, Katowice, Poland</footnote>

<footnote n="3">³Institute of Environmental Biology, University of Wroclaw, Wroclaw, Poland</footnote>
**The content and constituents of the essential oil in alien and native species of**
**Solidago L.**

Olga Shelepova<fnref n="1" />,<fnref n="2" />, Yulia Vinogradova<fnref n="1" />

Invasive species of Solidago for Europe – *S. gigantea* Ait. (9 specimens); *S. canadensis* L. (9 specimens), *S. rupestris* Raf. (2 specimens) and *S. graminifolia* (L.) Salisb. (= *Euthamia graminifolia* (L.) Nutt.) – were studied along with the native *S. virgaurea* L. (2 specimens). Comparison of yield and component composition of the essential oil in leaves and inflorescences of plants in different phenophases was carried out.

In indigenous *S. virgaurea* leaves and inflorescences contain trace amounts of essential oil (0.03-0.05%). In alien invasive species amount of essential oil in these organs increase in line *S. gigantea* (up to 0,16%) → *S. rupestris* (up to 0,22%) → *S. canadensis* (up to 0,44%) → *S. graminifolia* (0.55%).

Analysis of the component composition of the essential oil was performed by GC/MS. There are about 103 components, the main ones: α-Pinene, β-Pinene, β-Myrcene, Bornylacetate, Limonene, Germacrene D. The ratio of the main components is species-specific. In *S. gigantea* Bornylacetate (58%) and Germacrene D (to 28.2%) predominate; in *S. canadensis* - α-Pinene (to 61.2%) and Limonene (22.5%); in *S. rupestris* - α-Pinene (up 21,3%), Bornylacetate (up 20,9%), Germacrene D (28.8%) and Limonene (up 19.0%). In composition of the essential oil in *S. graminifolia* other components prevail - Sabinen -22,6%, β-Phellandrene -39,7% and β-Pinene - 14.3%. In indigenous *S. virgaurea* α-Pinene (up 33.6%) is the only major component, the proportion of other components does not exceed 7%.

Differences in quantity and composition of the essential oil component, depending on the ecological and climatic growth conditions, phenophase and the test plant's organ are revealed. It is proved that at the early flowering stage inflorescences of *S. gigantea* produce more essential oil than leaves - 0.11% vs. 0.03%.

In *S. gigantea*, depending on the population's locality, the main components' proportion varied in a wide range: α-Pinene (0,8-6,5%), Bornylacetate (9,7-57,9%), Germacrene D (0, 9-44,7%) and Limonene (0,3-4,5%). The maximal amount of essential oil (0.16%) was recorded for the plants at the northernmost collection point (N 56051'; E 35054') while the minimal (0.02%) - for the plants from the southernmost locality (N 47052'; E 17016').

Thus, the alien invasive species of *Solidago* exceed the indigenous *S. virgaurea* in quantity of essential oil and a greater variety of its main components. The significant difference in the component composition of the essential oil in *S. graminifolia* supports the legitimacy of this species' treatment within a separate genus *Euthamia*.

Keywords: Solidago species, essential oil, GC/MS

<footnote n="1">¹Main Botanical Garden RAS, Moscow, Russia</footnote>

<footnote n="2">²Research Institute of Human Ecology and Environmental Health, Moscow, Russia</footnote>
# Impact of the alien species *Opuntia humifusa* (Cactaceae) on the native plant diversity in Bulgaria

Vladimir Vladimirov, Tsvetelina Naydenova, Svetlana Bancheva

Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria

*Opuntia humifusa* (Cactaceae) is an American species which was first introduced to Bulgaria in the 1930-ties as an ornamental plant. Since then it has spread to numerous localities across the country growing in different habitats – sandy, rocky and grassy places, usually in sunny spots but also it withstands partial shading. The aim of this study was to reveal the impact of this invasive alien on the native flora and vegetation. For this purpose, 1×1 m plots with and without the invader were compared; in each locality 10 pairs of plots were studied. The following parameters were recorded: total number of vascular plant species in each plot, total vegetation cover, cover of each plant species, and maximal height of each species. The results suggest *Opuntia humifusa* is a successful competitor, significantly decreasing the available space to local plants. In some localities the species invades rare and vulnerable habitats and grows in close proximity to plant species of conservation concern. The poster presents the results of assessing the impact of the invader on the native plant diversity during two vegetation seasons.

Financial support by the Financial Mechanism of the European Economic Area (2009–2014), Programme BG03 ‘Biodiversity and Ecosystem Services’, under project ESENIAS-TOOLS is gratefully acknowledged.

Keywords: Bulgarian flora, ecological impact of invasive plants, neophytes, Opuntia
# Studies on populations of invasive plant species in Lithuania

Egidijus Žalneravičius, Zigmantas Gudžinskas

Nature Research Centre, Institute of Botany, Vilnius, Lithuania

The spread of alien species is creating complex challenges and poses a significant threat to the natural biological diversity, society, economic life and health of humans. Invasive plant species have considerable potential for changing community structure and ecosystem function of invaded areas. To date, more than 550 alien plant species have been registered in Lithuania and 19 of these are legally recognized as invasive species.

The aim of this research was to evaluate abundance, distribution, population structure and morphological parameters of invasive plant species as well as to estimate their impact on the state of protected species and habitats. Investigations on populations of invasive species were started in 2007. During the first stage of the implementation of the research tasks, populations of five species were surveyed. During the second stage of implementation (2014–2015), populations of 11 invasive species, i.e. *Amelanchier spicata*, *Bidens frondosa*, *Cytisus scoparius*, *Echinocystis lobata*, *Gypsophila paniculata*, *Impatiens parviflora*, *Prunus serotina*, *Robinia pseudoacacia*, *Rumex confertus*, *Solidago altissima* and *Solidago gigantea* were investigated. Studies were performed employing sampling-plot method. Herbaceous plant (including *Cytisus scoparius*) populations were evaluated in transects of 20 sampling plots of 1 m², woody plants – in transects of 10 sampling plots of 4 m². Sampled populations were selected mainly in protected areas (regional and national parks, strict nature reserves, nature reserves).

The research revealed the decrease of species diversity in the invaded habitats. Negative correlations among species diversity and both density and coverage of alien species were found in habitats invaded by *Solidago gigantea* and *Solidago altissima*. This study also revealed negative impact of invasive species on population structure and habitat conditions of the protected species such as *Linaria loeselii* (habitats invaded by *Gypsophila paniculata*), *Pulsatilla patens*, *Thesium ebracteatum* (habitats invaded by *Cytisus scoparius*), *Bolboschoenus maritimus*, *Cyperus fuscus*, *Teucrium scardium* (habitats invaded by *Bidens frondosa*).

Analysis of the data collected during the investigation revealed that invasive herbaceous plant species mainly affect open habitats, their plant communities and species diversity, whereas woody species threaten the stability of both open and forest habitats.

**Keywords:** habitats, impact, species diversity, population density, population structure, protected species
**The inland introduced aquatic fauna in Portugal**

Pedro Anastácio<fnref n="1" />, Filipe Ribeiro<fnref n="2" />, Ronaldo Sousa<fnref n="3" />, César Capinha<fnref n="4" />, Filipe Banha<fnref n="1" />, Ana Gama<fnref n="1" />,
Ana Filipe<fnref n="5" />, Rui Rebelo<fnref n="6" />

The Portuguese and the European Union legislations consider the need for management of some invasive species. Presently, species lists are being prepared at E.U. level, which include the need for management. In spite of this, so far there is no thorough review of the introductions of freshwater fauna in Portugal and this is essential for the establishment of management policies and priorities.

We obtained data for 95 introductions of freshwater or eurihaline Reptiles, Fish, Amphibians, Crustaceans, Mollusks and Other Invertebrates in Portugal, including the continental territory and the Azores and Madeira Islands. With this data we were able to present a list and discuss national statistics regarding the progression of the cumulative number of introduced species since 1800, the probable vectors of the introductions, the proportions of the main taxonomic groups represented and the area of origin of the species. Furthermore, we review the current knowledge regarding invasion risk assessment studies and of invasive species distribution models in the Portuguese territory, under current and future climatic conditions.

The first major boost in the number of introductions since 1800 was in the final period of the 19th century. Along the 20th century the number of introductions increased at an approximate rate of 2 species per decade until the 1970's. Since this period, the rate of introductions increased dramatically to approximately 7 species per decade. Fish and Mollusks are the main taxonomic groups found, with more than half of the introduced species. Regarding the geographic origin of the species, most of these are from Europe and North America, representing over 70% of the species.

From the available literature, only ten species were subjected to distribution modelling and have data for the Portuguese territory. The major finding is that of the modelled species only one has fulfilled its distribution potential in the continental area. None of these models includes fish, which are the major group of introduced species and only a minority of these models provides projections for future distributions, namely under scenarios of climate change. In spite of the absence of distribution models for fish, so far risk identification tools have been applied mostly to fish on a national context.

Keywords: Freshwater, Fish, Crustaceans, Mollusks, Review, Portugal

<footnote n="1">¹MARE - Center for Marine and Environmental Sciences University of Évora, Évora, Portugal</footnote>

<footnote n="2">²MARE – Marine and Environmental Sciences Centre Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal</footnote>

<footnote n="3">³CBMA — Centre of Molecular and Environmental Biology, Department of Biology, University of Minho IB-S, Institute of Science and Innovation for Bio-Sustainability Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), Braga, Portugal</footnote>

<footnote n="4">⁴CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Cátedra REFER-Biodiversidade, Universidade do Porto, Vairão, Portugal</footnote>

<footnote n="5">⁵Cátedra EDP-Biodiversidade, ApplEcol Group\ CIBIO/InBIO (Centro de Investigação em Biodiversidade e Recursos Genéticos / Rede de Investigação em Biodiversidade e Biologia Evolutiva), Lisbon, Portugal</footnote>

<footnote n="6">⁶Department of Animal Biology and Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa (cE3c-FCUL), Lisbon, Portugal</footnote>
# Modelling habitat suitability to predict the invasive potential of the raccoon (*Procyon lotor*) in Luxembourg

Lisette Cantú Salazar¹, Xavier Mestdagh¹, Laurent Schley²

¹Luxembourg Institute of Science and Technology, Department of Environmental Research and Innovation, Belvaux, Luxembourg

²Ministère du Développement durable et des Infrastructures, Administration de la nature et des forêts, Diekirch, Luxembourg

Accurate knowledge on species occurrence and distribution is a prerequisite for appropriate conservation or management, particularly in the case of invasive species. The raccoon (*Procyon lotor*) is a species native to North and Central America, but alien populations are established around the world, including Europe, where it is now listed within the 100 worst invasive alien species. In the introduced range, it is often assumed that raccoons may have an impact on breeding birds and amphibians, transmit pathologies to humans and other wild species, and damage crops.

In Germany, raccoon populations were confined to a relatively small area for c.20 years after introduction, but expansion towards new areas accelerated in the following years. In Luxembourg, raccoon presence was first confirmed in the late 1970s, but despite more than three decades of establishment, available records show that the species occupies mostly areas in the North-West of the country, with a sporadic presence in the South. However, the invasive potential of the species towards southern regions needs to be better understood.

Habitat suitability models are a useful tool that relate variables describing environmental conditions with existing species records, and use this statistical relationship to predict the suitability of unsampled sites to obtain spatially explicit and continuous surfaces indicating the probability of species occurrence.

In this study, we used nation-wide raccoon presence-only data, mostly derived from the National Biodiversity Monitoring Program, and the Maximum Entropy (MaxEnt) algorithm, to build 200-m and 1000-m resolution habitat suitability models in order to identify sites potentially suitable for future invasions at the national level. Congruent with the patterns shown by the distribution of available presence data and hunting bag data, our models suggest a higher habitat suitability in North-West Luxembourg and a relatively low suitability in the South-East region, highlighting areas where the species could already be potentially present or could expand to, given its relative suitability across Luxembourg.

Keywords: raccoon, Procyon lotor, invasive potential, habitat suitability models, MaxEnt
**Niche shifts are common in globally invasive insects**

Matthew Hill<fnref n="1" />, Belinda Gallardo<fnref n="2" />, John Terblanche<fnref n="1" />

Invasive and pest insects have major impacts on ecosystem function, agricultural production and human health. To predict the geographic distributions of these species, correlative Ecological Niche Models (ENMs) are typically used. Such methods rely on assumptions of niche conservatism in space and time, although there is increasing evidence that many species are undergoing niche shifts during biological invasions. The magnitude and direction of niche shifts, however, is likely to vary within and between taxonomic groups, highlighting that assessment of these is required. We compiled a novel database of globally invasive insect species and test for niche shift, including geographic range expansion and unfilling, across this group. We then examine if factors such as the native range size, poleward shifts and human influence may be associated with the observed niche changes. Finally, we build ENMs for all species and examine the reliability of their predictions in light of the identified niche shift results. Niche expansion was high for this group, and apparent in 15 of the 22 species. Niche unfilling occurred in 50% of the study species. Human influence of the native range explained 50% of niche expansion, and poleward movement accounted for 40% in niche unfilling. Models suggested that species tend to invade areas with similar disturbance regimes to their native range, and that species tend to achieve their full invasive potential (low unfilling and expansion) when moving towards higher latitudes. Poleward and equatorial shifts are however associated with amounts of niche unfilling. These invasive insects undergo niche shifts that are likely associated with human influences, such as modified or transformed habitats that promote establishment and invasion of exotic species. Therefore, the use of ENMs for this group must take into considerations that these species are often not in equilibrium with their environment when making predictions of invasion potential.

Keywords: niche expansion, niche unfilling, invasive insect, invasive ants, ecological niche models (ENM), human disturbance

<footnote n="1">¹Centre of Excellence for Invasion Biology, Stellenbosch University, Matieland, South Africa</footnote>

<footnote n="2">²Pyrenean Institute of Ecology (IPE-CSIC), Zaragoza, Spain</footnote>
Linkages between ecological features and *Amorpha fruticosa* (Mill.) occurrence in selected protected areas from Romania and Slovakia

Mihai Doroftei¹, Gheorghe Kuscicsa², Ines Grigorescu², Monica Dumitrascu², Peter Ferus³,
Gabriel Herlo⁴, Mihaela Nastase⁵

¹Danube Delta National Institute for Research and Development, Tulcea, Romania

²Institute of Geography, Romanian Academy, Bucharest, Romania

³Mlynany Arboretum, Institute of Forest Ecology, Slovak Academy of Sciences, Nitra, Slovakia

⁴Mures Floodplain Natural Park, Ceala, Romania

⁵Protected Areas Department, Romanian Forest Administration, Bucuresti, Romania

Generally, invasive species are known to have high adaptability to new environments and human activities, thus particularly disturbed habitats have the potential to become prone to invasions. The paper is aiming to present some research findings on the relationships between ecological features and invasive false indigo-bush (*Amorpha fruticosa*) in selected wetland areas from two countries: Romania (Comana Natural Park and Mureş Floodplain Natural Park) and Slovakia (Dunajské luhy Protected Landscape Area).

The authors will perform spatial and statistical correlations in order to highlight the relationships
between the selected invasive species and its main ecological conditions: soil properties, plant
diversity, structural features, habitat preferences and biological indicators (abundance,
frequency, coverage and ecological significance). Thus, soil sampling campaigns were carried
out in each protected area, in several habitat types (e.g. agricultural, wetlands, pastures) and
under specific setting conditions: areas with high abundance with *Amorpha fruticosa* and in
areas without *Amorpha fruticosa*. The resulted statistical analyses will emphasize statistical
dependencies between soil content (e.g. heavy metal, pH, humus, iron) and species occurrence
under the specific habitat characteristics of the areas where the sampling took place. Overall,
the outcomes of the current investigation will provide valuable information for further studies
on modelling the potential distribution of invasive species in relation to soil parameters and
main habitat features.

The current research was carried out in the framework of the EU FP7 - Building Capacity for Black Sea Catchment Observation and Assessment System supporting Sustainable Development (EnviroGRIDS) and the Inter-Academic Research Agreement between the Institute of Geography, Romanian Academy and Mlyňany Arboretum, Institute of Forest Ecology, Slovak Academy of Sciences.

Keywords: ecological features, statistical analysis, Amorpha fruticosa, protected areas,
Romania, Slovakia
# A GIS-based statistical analysis for the assessment of *Amorpha fruticosa* (Mill.) potential distribution in Comana Natural Park (Romania)

Gheorghe Kucsics<fnref n="1" />, Ines Grigorescu<fnref n="1" />, Monica Dumitrascu<fnref n="1" />, Mihai Doroftei<fnref n="2" />, Mihaela Nastase<fnref n="3" />, Carmen Dragota<fnref n="1" />, Cristina Dumitrica<fnref n="1" />, Peter Ferus<fnref n="4" />

It is acknowledged the major threat that invasive species pose to biodiversity causing significant structural and functional transformations to ecosystems. In line with that, the current study is seeking to assess the potential distribution of an invasive terrestrial plant species (ITPS) *Amorpha fruticosa* (Mill.) in a natural protected area i.e. Comana Natural Park (V IUCN category). The study-area is located in the southern part of Romania (Romanian Plain), hosting habitats, as well as plant and animal species of great scientific value overlapping the Continental biogeographical region, also designated as RAMSAR and Natura 2000 sites.

Field surveys revealed the dominance of the analyzed species in the surroundings of wetlands, river channels and alongside the transportation network, especially on the spoiled soils located next to the non-electrified railroads, as well as in the outskirts of forests. As a result, connecting this invasive species with its triggering driving forces (natural and human-induced) becomes essential in understanding its environmental preferences and predicting its potential spread. The authors propose an integrated geographical GIS-based quantitative statistical analysis aimed at assessing the occurrence, development and potential distribution of *Amorpha fruticosa* in relation to the importance of the identified key explanatory factors. The proposed methodology (potential distribution index – PODIS-I) relies on the ranking and weighting of each selected driving factor depending the relationship with the analysed species. Finally, a map displaying areas with different probability of occurrence of *A. fruticosa* in the study-area will result.

Applying an integrated methodology for assessing the spatial potential distribution of invasive plant species is particularly useful for selecting the best measures to eliminate or prevent their spreading.

The current research was undertaken in the framework of the EU FP7 – Building Capacity for Black Sea Catchment Observation and Assessment System supporting Sustainable Development (EnviroGRIDS).

Keywords: Amorpha fruticosa, potential distribution, statistical analysis, Comana Natural Park, Romania

<footnote n="1">¹Institute of Geography, Romanian Academy, Bucharest, Romania</footnote>

<footnote n="2">²Danube Delta National Institute for Research and Development, Tulcea, Romania</footnote>

<footnote n="3">³Protected Areas Department, Romanian Forest Administration, Bucharest, Romania</footnote>

<footnote n="4">⁴Mlynany Arboretum, Institute of Forest Ecology, Slovak Academy of Sciences, Nitra, Slovakia</footnote>
# Alien plants change α- and β-diversity patterns along elevation gradients: a global analysis

Sylvia Haider<fnref n="1" />,<fnref n="2" />, Jake Alexander<fnref n="3" />, Christoph Kueffer<fnref n="3" />, Aníbal Pauchard<fnref n="4" />,<fnref n="5" />

Mountains are of great significance for the world's biodiversity, and in the last two decades, research about elevational species richness patterns has gained attention. Historically, biodiversity patterns have been shaped by natural factors such as climatic gradients. Nowadays, alien species may be changing biodiversity patterns along elevation gradients. Such changes might be even more pronounced due to anthropogenic habitat disturbances.

We present a global analysis of plant species diversity along elevation gradients in mountains that is based on a systematic survey in nine regions from different continents and hemispheres. We recorded the native and alien vascular plants community in plots of standardized size and equal spread along the maximum extent of the elevation gradient. Thereby we simultaneously addressed the effect of two drivers of global change: alien plants and human induced disturbance (roadsides).

Alien species richness (α-diversity) declined with elevation, while for native richness the most common pattern was a positive unimodal distribution. Alien species shifted the peak of total species richness towards lower elevations; an effect that was more pronounced at roadsides. Spatial species turnover (β-diversity) was reduced through the addition of alien species and at roadsides, but elevation did not have a consistent effect. We further found that community dissimilarity increases with elevational distance (decay-by-elevation) and that this effect was attenuated by alien species.

We conclude that although elevation is a major determinant in biodiversity assembly, it has very different effects on native and alien species and this effect is modulated by local disturbance. Our results also show that different measures of biodiversity do not necessarily respond in the same way to different global change drivers, and therefore it is important to quantify multiple dimensions of biodiversity. Further, our results underline that severe alterations of mountain biodiversity are occurring, since mountains are faced with increasing anthropogenic influence, including the introduction and spread of alien species.

This research is part of the Mountain Invasion Research Network (MIREN).

Keywords: Mountain invasions, elevation gradients, species richness, community similarity, biodiversity patterns, global change, anthropogenic disturbance

<footnote n="1">¹Martin Luther University Halle-Wittenberg Institute of Biology / Geobotany and Botanical Garden, Halle, Germany</footnote>

<footnote n="2">²German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany</footnote>

<footnote n="3">³ETH Zurich, Department of Environmental Systems Science, Institute of Integrative Biology, Zurich, Switzerland</footnote>

<footnote n="4">⁴Universidad de Concepción, Laboratorio de Invasiones Biológicas, Concepción, Chile</footnote>

<footnote n="5">⁵Institute of Ecology and Biodiversity (IEB), Concepción, Chile</footnote>
**Do invasive plants in Croatia share same environmental envelopes?**

Sven Jelaska, Nina Vuković, Toni Nikolić

Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia

We have compared impact of three groups of environmental variables in explaining distribution of invasive plants in Croatia, i.e. climate data (presented with seasonal precipitation and mean temperature), basic topographical variables (slope, and sine and cosine of aspect) and proxies for disturbance (human population density, distance from the settlements and distance from the traffic infrastructure i.e. roads and railways). While topography variables seem to be almost irrelevant, those serving as proxies for disturbance turns out to be more important than climatic ones for significant share of invasive species (e.g. *Amaranthus retroflexus*, *Ambrosia artemisiifolia*, *Chamomila suaveolens*, *Conyza bonariensis*, *Galinsoga parviflora*, *Reynoutria x bohemica*, *Veronica persica*), with particular emphasis on the population density. Among the seasonal climatic variables, the amount of precipitation was more important in explaining current distribution then the mean temperature, with exception of spring, although latter was observed in only few species with lower significance (e.g. *Amorpha fruticosa*, *Acer negundo*). Although not included in these models, and not easy to implement, it seems that invasion pathways (partly included through the disturbance proxies) could play one of the main roles in explaining significant number of invasive plant distribution. There is no doubt that prevailing environmental conditions sets up the scene, but pathways might be dominant factor that do the casting i.e. selecting the species that will have chance to express their invasiveness.

Keywords: Croatia, distribution, modelling, GIS
European anthropogenic, semi-natural and natural habitats as sources of
naturalized plant species worldwide

Veronika Kalusová<fnref n="1" />, Milan Chytrý<fnref n="1" />, Petr Pyšek<fnref n="2" />,<fnref n="3" />, Mark van Kleunen<fnref n="4" />, Ladislav Mucina<fnref n="5" />

Large-scale patterns of plant invasion and their determinants in different habitat types are receiving increasing attention. This research has mainly focused on invasion in habitats in recipient areas, but recently also the importance of habitat types from which alien species originated in the source areas is recognised as a factor controlling observed patterns. We explored European anthropogenic, semi-natural and natural habitats as sources of plants that became naturalised in other parts of the World. Our dataset encompassed 10,741 vascular plant species assigned to 37 habitat types classified into habitat groups reflecting the intensity of human impact, based on European vegetation classification system (Mucina et al. submitted). Within each habitat type and habitat group, species naturalised outside Europe were identified using the GloNAF database (van Kleunen et al. 2015). European habitat types, providing the highest proportion of naturalized species, included anthropogenic weed and perennial ruderal vegetation, semi-natural to natural grasslands and wetlands, riparian forests, and eutrophic forests, and species from these habitats were also most successful in terms of the number of GloNAF regions occupied. The European species with the widest naturalization range, as measured by the sum of regions in which they naturalized, originated in anthropogenic weed vegetation. Successful were also species occurring in both semi-natural grasslands and weed vegetation. Among species of natural habitat types, generalists able to occur in anthropogenic as well as in semi-natural habitat types have naturalised most frequently.

Keywords: alien plant species, donor habitat, native range

<footnote n="1">¹Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic</footnote>

<footnote n="2">²Institute of Botany, The Czech Academy of Sciences, Pruhonice, Czech Republic</footnote>

<footnote n="3">³Department of Ecology, Faculty of Science, Charles University in Prague, Praha, Czech Republic</footnote>

<footnote n="4">⁴Ecology, Department of Biology, University of Konstanz, Konstanz, Germany</footnote>

<footnote n="5">⁵Iluka Chair in Vegetation Science and Biogeography, School of Plant Biology, The University of Western Australia, Perth, Australia</footnote>
**What is the role of vacant niches for alien species establishment on isolated islands?**

Bernd Lenzner¹, Franz Essl¹, César Capinha², Wayne Dawson³, Stefan Dullinger¹, Evan Economo⁴, ⁵, Benoit Guénard⁴, ⁶, Holger Kreft⁷, Jan Pergl⁸, Petr Pyšek⁸, Hanno Seebens⁹, Mark van Kleunen¹⁰, Patrick Weigelt⁷, Marten Winter¹¹, Dietmar Moser¹

¹Division of Conservation Biology, Vegetation and Landscape Ecology University of Vienna, Austria, Vienna, Austria

²CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Cátedra REFER-Biodiversidade, Universidade do Porto, Porto, Portugal

³School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom

⁴Okinawa Institute of Science and Technology, Graduate University, Okinawa, Japan

⁵Department of Ecology and Evolutionary Biology, University of Michigan, Michigan, United States

⁶School of Biological Sciences, University of Hong Kong, Hong Kong, China

⁷Biodiversity, Macroecology & Conservation Biogeography Group, University of Göttingen, Göttingen, Germany

⁸Institute of Botany, Department of Invasion Ecology, Academy of Sciences of the Czech Republic, Pruhonice, Czech Republic

⁹Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung, Frankfurt am Main, Germany

¹⁰Ecology, University of Konstanz, Konstanz, Germany

¹¹German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany

Globally, islands are major biodiversity hotspots. The intrinsic properties of islands promote the evolution of highly specialized and range-restricted native biota which is mainly driven by island area, age and isolation. Isolation restricts natural dispersal of species, leading to the absence of some functional groups in the local species pool that play a key role in mainland regions. It has been suggested that such empty ecological space may facilitate establishment of new species and contribute to the high levels of biological invasions widely observed on islands worldwide.

We test the importance of “vacant niches” to explain differences in the level of invasion in a wide range of subtropical and tropical islands and island groups. The dataset encompasses information on established alien species richness from a range of important taxonomic groups that represent plants (vascular plants), vertebrates (mammals, amphibians, reptiles) and invertebrates (ants). We assess the effect of island isolation on alien species numbers and on the observed level of invasion while accounting for area, climate and physical as well as economic properties of islands by means of generalized linear mixed effect models. We will present results of this analysis, which are highly relevant for understanding the biogeography and macroecology of island invasions and to inform alien species management and policy.

Keywords: alien species, ants, amphibians, biogeography, introduction effort, isolation, macroecology, mammals, reptiles, vacant niches, vascular plants
# A dynamic modeling approach for estimating the potential distribution of the invasive Asian *Ambrosia* beetle *Xyleborus glabratus* Eichhoff in North America

Andrés Lira-Noriega<fnref n="1" />, Luis Osorio-Olvera<fnref n="2" />, Jorge Soberón<fnref n="3" />

Since its introduction to the east coast of the United States in 2002, the fungus *Raffaelea lauricola* T.C. Harr., Fraedrich & Aghayeva, which is transmitted by the ambrosia beetle *Xyleborus glabratus* Eichhoff (Coleoptera: Curculionidae: Scolytinae), has caused major mortalities to species of trees in the Lauraceae family. Here we present the predictions of the invasion dynamics of *X. glabratus* 25 years after its introduction across North America using a spatially explicit dynamic modeling approach based on a logistic growth model that incorporates dispersal. Results show how the distribution of the species is shaped by a heterogeneous set of favourable conditions (belonging to the abiotic ecological niche) and resource availability (distribution of Lauraceae tree species) and could replicate the known distributional pattern for this beetle from 2002 to 2015 in the United States. Results also indicate that this modeling approach has several advantages over correlative approximations to detect and predict species' distributions. The incorporation of population processes associated to the intrinsic population growth rate and dispersal in process-based modeling represents an advantage when modeling species geographic distributions because these allow us estimating the relevance of parameters related to the movement and colonization of the species in contrast to solely the abiotic ecological niche, thus providing a better means of assessing the potential distribution of a given species through time. This in turn allows us estimating how the process of dispersal and colonization can be achieved by the species depending on the initial conditions, which inform us on the potential success of an invasion.

Keywords: ambrosia beetle, ecological niche, invasive species, potential distribution, suitability, process-based modeling

<footnote n="1">¹Instituto de Ecología, A.C., Xalapa, Mexico</footnote>

<footnote n="2">²Facultad de Ciencias, Universidad Nacional Autónoma de México, DF, Mexico</footnote>

<footnote n="3">³Biodiversity Institute, The University of Kansas, Lawrence, United States</footnote>
**Effect of alien species on the phylogenetic structure of plant species pools**

Zdeňka Lososová, et al.

Dept. of Botany and Zoology, Masaryk University, Brno, Czech Republic

One of the key questions of invasion biology is to identify which factors facilitate species invasion. A number of hypotheses postulate that invasion is strongly influenced by the interplay between the phylogeny of the alien species and the phylogenetic structure of invaded communities. Some hypotheses predict that aliens phylogenetically related to native species in invaded communities are more successful invaders, because of appropriate niche-adaptation. Another hypothesis predicts that phylogenetic relatedness hampers naturalization because of niche overlap with native species. We thus asked whether or not differences in the phylogenetic structure of native species pools affect the number of alien species. We used species pools of 88 vegetation types occurring in central Europe, comprising 2306 species. For each species pool, we quantified phylogenetic diversity using mpd and mntd indices to test the relationship between it and the level of invasion. The level of invasion was strongly vegetation-type dependent, and it was related to both the phylogenetic structure of the species pools, and the phylogenies of the invading species. The species pools with the largest proportion of alien species were those of anthropogenic habitats and open riverine, wet or mesic meadows. These species pools are phylogenetically more clustered possibly due to disturbance acting as environmental filter. Here, alien species increased the degree of phylogenetic clustering as they tended to be from the same lineages as native species. Such trends were not detected for phylogenically diverse species pools such as those of forests. Our findings do not support the Darwin's naturalization hypothesis; they rather suggest that the alternative hypothesis of environmental filtering is the important mechanism in play.

Keywords: Archaeophyte, biological invasions, neophyte, phylogenetic diversity, species pool, vegetation type.
**Urban plant communities: testing the mesic hypothesis of invasibility**

Zdeňka Lososová, et al.

Masaryk University, Brno, Czech Republic

Urban land use provides new habitats by creating new combinations of abiotic factors and by bringing together species that otherwise would live in different regions of the world or in different habitats within the same region. Current urban plant communities are thus composed of native as well as alien species and the level of invasibility of urban communities varies between habitats and climatic regions.

The aims of our study were to identify factors which shape structure and function of urban plant communities, to determine relationships between structure of urban communities and their invasibility. Specifically, we tested the mesic hypothesis of plant invasibility, which predicts that the level of invasion is higher in mesic environments than in both dry/warm and cold/wet environments. We tested this hypothesis using a data set of 420 vegetation plots from different urban habitats of 60 large European cities.

Keywords: Europe, level of invasion, urban ecology, urban habitat
# Factors explaining the historical and present distribution of an invasive species, *Ventenata dubia*, in its native range

Dorothy Maguire, et al.

USDA-ARS (EBCL), Montpellier, France

Boise State University, Boise, United States

*Ventenata dubia* is a species of grass of conservation concern in many parts of Europe. Its historical range has shifted, and places where it was once abundant, it has become rare, or even extinct in some cases. This species is of particular interest because while rare in its native range, it has become highly invasive in the United States. Several factors may have influenced the distribution of this species. First, the northward shift in its range over time suggests climate could be an important factor. Second, *Ventenata* has historically been found in areas with frequent low intensity disturbance, and therefore land use change may also play an important role. Understanding how these biogeographical factors influence *Ventenata*'s distribution in its native range, may help us understand both its threatened status in Europe, and why it has become a pest in north America.

The objective of our study was therefore to determine if there has been a range shift of this
species in its native range, and to assess the role that climate and land use change have had on
the distribution. Secondly we compare the native and invasive ranges to determine whether or
not the species distribution in the two ranges is limited by similar biogeographical factors.
Using presence data from a combination of herbarium specimens, floristic survey data, literature
reviews, and field surveys, we assessed the historical and current distribution of *Ventenata*
throughout its native and invasive ranges. In combination with climate and land use data, we
construct species distribution models for *Ventenata*. Our results could both aid in the
conservation of this species in its native range, and be used to inform predictive models of this
species' spread in its invasive range.

Keywords: Ventenata dubia, range shifts, species distributions, invasive species, biogeography, Niche shifts
Alien ladybirds (Coccinellidae) established in European Russia and neighbouring countries

Marina Orlova-Bienkowskaja<fnref n="1" />, Ilya Zakharov<fnref n="2" />, Andrzej Bienkowski<fnref n="1" />

More than 20 species of Coccinellidae were introduced for pest control in the Soviet Union. Six of them have established.

(1) *Chilocorus bijugus* was introduced from India to Georgia in 1973 to control *Quadraspidiotus perniciosus* and established near Batumi.

(2) *Cryptolaemus montrouzieri* native for Australia was released to control Pseudococcidae and Coccidae many times from 1933 in different regions including Abkhazia, Azerbaijan, Uzbekistan, but thought to be not established. In 2011 and 2012 established populations were found in the south of Russia (Sochi) and Abkhazia.

(3) *Harmonia axyridis* from the Far East was released for control of aphids in Georgia, the Ukraine, Belarus and Kazakhstan. In spite of massive releases since 1927 the species was thought to be not established before 2002. Now it is established in the Ukraine, Moldova, Belarus and European Russia: Kaliningrad, Rostov, Krasnodar and Stavropol regions, Adygea, the Crimea, Dagestan, Kabardino-Balkaria. Individual adults are also found in Belgorod, Lipetsk and Moscow regions. In some regions individual specimens were found well before the eastern border of European range became close: in 2002 in Eastern Georgia, in 2005 in Abkhazia, in 2003 in Kiev (the Ukraine). The population exists near Kiev since 2007. Population in southeastern Kazakhstan and Kirgizstan is neither native nor a result of intentional introduction and appeared as a result of unintentional introduction from the western part of the native range.

(4) *Lindorus lophantae* native to Australia was released for control of Diaspididae in 1948 in Georgia, Crimea south Russia. Established population was detected in Georgia. The whole population of *L. lophantae* in the Caucasus derives from laboratory culture, established from just one pair of insects collected in Italy.

(5) *Rodolia cardinalis* native to Australia was released to control *Icerya purchase* in Georgia and Azerbaijan (many releases since 1932) and established in the Black Sea shore. Current state of population is unknown.

(6) *Serangium parcesetosum* native to India was released in 1973 in Georgia, Abkhazia, Azerbaijan and south Russia (Sochi) to control *Dialeurodes citri* (Aleyrodidae). *S. parcesetosum* established and began to spread spontaneously. The local populations were re-novated by additional releases from laboratory culture.

The study by the first author was supported by RFBR № 15-29-02550, second author – by RSF № 16-16-00079, third author – by RSF № 16-14-10031.

Keywords: biocontrol, Chilocorus bijugus, Cryptolaemus montrouzieri, Harmonia axyridis, Lindorus lophantae, Rodolia cardinalis, Serangium parcesetosum

<footnote n="1">¹A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia</footnote>

<footnote n="2">²Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia</footnote>