Moussab/ORKG-training-evaluation-set huggingface dataset:
Research field: Ecology and Evolutionary Biology
Title: Release from foliar and floral fungal pathogen species does not explain the geographic spread of naturalized North American plants in Europe
Abstract: 1 During the last centuries many alien species have established and spread in new regions, where some of them cause large ecological and economic problems. As one of the main explanations of the spread of alien species, the enemy‐release hypothesis is widely accepted and frequently serves as justification for biological control. 2 We used a global fungus–plant host distribution data set for 140 North American plant species naturalized in Europe to test whether alien plants are generally released from foliar and floral pathogens, whether they are mainly released from pathogens that are rare in the native range, and whether geographic spread of the North American plant species in Europe is associated with release from fungal pathogens. 3 We show that the 140 North American plant species naturalized in Europe were released from 58% of their foliar and floral fungal pathogen species. However, when we also consider fungal pathogens of the native North American host range that in Europe so far have only been reported on other plant species, the estimated release is reduced to 10.3%. Moreover, in Europe North American plants have mainly escaped their rare, pathogens, of which the impact is restricted to few populations. Most importantly and directly opposing the enemy‐release hypothesis, geographic spread of the alien plants in Europe was negatively associated with their release from fungal pathogens. 4 Synthesis. North American plants may have escaped particular fungal species that control them in their native range, but based on total loads of fungal species, release from foliar and floral fungal pathogens does not explain the geographic spread of North American plant species in Europe. To test whether enemy release is the major driver of plant invasiveness, we urgently require more studies comparing release of invasive and non‐invasive alien species from enemies of different guilds, and studies that assess the actual impact of the enemies.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Entomofauna of the introduced Chinese Tallow Tree
Abstract: Abstract Entomofauna in monospecific stands of the introduced Chinese tallow tree (Sapium sebiferum) and native mixed woodlands was sampled in 1982 along the Texas coast and compared to samples of arthropods from an earlier study of native coastal prairie and from a study of arthropods in S. sebiferum in 2004. Species diversity, richness, and abundance were highest in prairie, and were higher in mixed woodland than in S. sebiferum. Nonmetric multidimensional scaling distinguished orders and families of arthropods, and families of herbivores in S. sebiferum from mixed woodland and coastal prairie. Taxonomic similarity between S. sebiferum and mixed woodland was 51%. Fauna from S. sebiferum in 2001 was more similar to mixed woodland than to samples from S. sebiferum collected in 1982. These results indicate that the entomofauna in S. sebiferum originated from mixed prairie and that, with time, these faunas became more similar. Species richness and abundance of herbivores was lower in S. sebiferum, but proportion of total species in all trophic groups, except herbivores, was higher in S. sebiferum than mixed woodland. Low concentration of tannin in leaves of S. sebiferum did not explain low loss of leaves to herbivores. Lower abundance of herbivores on introduced species of plants fits the enemy release hypothesis, and low concentration of defense compounds in the face of low number of herbivores fits the evolution of increased competitive ability hypothesis.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Effects of large enemies on success of exotic species in marine fouling communities of Washington, USA
Abstract: The enemy release hypothesis, which posits that exotic species are less regulated by enemies than native species, has been well-supported in terrestrial systems but rarely tested in marine systems. Here, the enemy release hypothesis was tested in a marine system by excluding large enemies (>1.3 cm) in dock fouling communities in Washington, USA. After documenting the distribution and abundance of potential enemies such as chitons, gastropods and flatworms at 4 study sites, exclusion experiments were conducted to test the hypotheses that large grazing ene- mies (1) reduced recruitment rates in the exotic ascidian Botrylloides violaceus and native species, (2) reduced B. violaceus and native species abundance, and (3) altered fouling community struc- ture. Experiments demonstrated that, as predicted by the enemy release hypothesis, exclusion of large enemies did not significantly alter B. violaceus recruitment or abundance and it did signifi- cantly increase abundance or recruitment of 2 common native species. However, large enemy exclusion had no significant effects on most native species or on overall fouling community struc- ture. Furthermore, neither B. violaceus nor total exotic species abundance correlated positively with abundance of large enemies across sites. I therefore conclude that release from large ene- mies is likely not an important mechanism for the success of exotic species in Washington fouling communities.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Low prevalence of haemosporidian parasites in the introduced house sparrow (Passer domesticus) in Brazil
Abstract: Species that are introduced to novel environments can lose their native pathogens and parasites during the process of introduction. The escape from the negative effects associated with these natural enemies is commonly employed as an explanation for the success and expansion of invasive species, which is termed the enemy release hypothesis (ERH). In this study, nested PCR techniques and microscopy were used to determine the prevalence and intensity (respectively) of Plasmodium spp. and Haemoproteus spp. in introduced house sparrows and native urban birds of central Brazil. Generalized linear mixed models were fitted by Laplace approximation considering a binomial error distribution and logit link function. Location and species were considered as random effects and species categorization (native or non-indigenous) as fixed effects. We found that native birds from Brazil presented significantly higher parasite prevalence in accordance with the ERH. We also compared our data with the literature, and found that house sparrows native to Europe exhibited significantly higher parasite prevalence than introduced house sparrows from Brazil, which also supports the ERH. Therefore, it is possible that house sparrows from Brazil might have experienced a parasitic release during the process of introduction, which might also be related to a demographic release (e.g. release from the negative effects of parasites on host population dynamics).
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Range-expanding populations of a globally introduced weed experience negative plant-soil feedbacks
Abstract: Background Biological invasions are fundamentally biogeographic processes that occur over large spatial scales. Interactions with soil microbes can have strong impacts on plant invasions, but how these interactions vary among areas where introduced species are highly invasive vs. naturalized is still unknown. In this study, we examined biogeographic variation in plant-soil microbe interactions of a globally invasive weed, Centaurea solstitialis (yellow starthistle). We addressed the following questions (1) Is Centaurea released from natural enemy pressure from soil microbes in introduced regions? and (2) Is variation in plant-soil feedbacks associated with variation in Centaurea's invasive success? Methodology/Principal Findings We conducted greenhouse experiments using soils and seeds collected from native Eurasian populations and introduced populations spanning North and South America where Centaurea is highly invasive and noninvasive. Soil microbes had pervasive negative effects in all regions, although the magnitude of their effect varied among regions. These patterns were not unequivocally congruent with the enemy release hypothesis. Surprisingly, we also found that Centaurea generated strong negative feedbacks in regions where it is the most invasive, while it generated neutral plant-soil feedbacks where it is noninvasive. Conclusions/Significance Recent studies have found reduced below-ground enemy attack and more positive plant-soil feedbacks in range-expanding plant populations, but we found increased negative effects of soil microbes in range-expanding Centaurea populations. While such negative feedbacks may limit the long-term persistence of invasive plants, such feedbacks may also contribute to the success of invasions, either by having disproportionately negative impacts on competing species, or by yielding relatively better growth in uncolonized areas that would encourage lateral spread. Enemy release from soil-borne pathogens is not sufficient to explain the success of this weed in such different regions. The biogeographic variation in soil-microbe effects indicates that different mechanisms may operate on this species in different regions, thus establishing geographic mosaics of species interactions that contribute to variation in invasion success.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Remote analysis of biological invasion and the impact of enemy release
Abstract: Escape from natural enemies is a widely held generalization for the success of exotic plants. We conducted a large-scale experiment in Hawaii (USA) to quantify impacts of ungulate removal on plant growth and performance, and to test whether elimination of an exotic generalist herbivore facilitated exotic success. Assessment of impacted and control sites before and after ungulate exclusion using airborne imaging spectroscopy and LiDAR, time series satellite observations, and ground-based field studies over nine years indicated that removal of generalist herbivores facilitated exotic success, but the abundance of native species was unchanged. Vegetation cover <1 m in height increased in ungulate-free areas from 48.7% +/- 1.5% to 74.3% +/- 1.8% over 8.4 years, corresponding to an annualized growth rate of lambda = 1.05 +/- 0.01 yr(-1) (median +/- SD). Most of the change was attributable to exotic plant species, which increased from 24.4% +/- 1.4% to 49.1% +/- 2.0%, (lambda = 1.08 +/- 0.01 yr(-1)). Native plants experienced no significant change in cover (23.0% +/- 1.3% to 24.2% +/- 1.8%, lambda = 1.01 +/- 0.01 yr(-1)). Time series of satellite phenology were indistinguishable between the treatment and a 3.0-km2 control site for four years prior to ungulate removal, but they diverged immediately following exclusion of ungulates. Comparison of monthly EVI means before and after ungulate exclusion and between the managed and control areas indicates that EVI strongly increased in the managed area after ungulate exclusion. Field studies and airborne analyses show that the dominant invader was Senecio madagascariensis, an invasive annual forb that increased from < 0.01% to 14.7% fractional cover in ungulate-free areas (lambda = 1.89 +/- 0.34 yr(-1)), but which was nearly absent from the control site. A combination of canopy LAI, water, and fractional cover were expressed in satellite EVI time series and indicate that the invaded region maintained greenness during drought conditions. These findings demonstrate that enemy release from generalist herbivores can facilitate exotic success and suggest a plausible mechanism by which invasion occurred. They also show how novel remote-sensing technology can be integrated with conservation and management to help address exotic plant invasions.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Diversity, loss, and gain of malaria parasites in a globally invasive bird
Abstract: Invasive species can displace natives, and thus identifying the traits that make aliens successful is crucial for predicting and preventing biodiversity loss. Pathogens may play an important role in the invasive process, facilitating colonization of their hosts in new continents and islands. According to the Novel Weapon Hypothesis, colonizers may out-compete local native species by bringing with them novel pathogens to which native species are not adapted. In contrast, the Enemy Release Hypothesis suggests that flourishing colonizers are successful because they have left their pathogens behind. To assess the role of avian malaria and related haemosporidian parasites in the global spread of a common invasive bird, we examined the prevalence and genetic diversity of haemosporidian parasites (order Haemosporida, genera Plasmodium and Haemoproteus) infecting house sparrows (Passer domesticus). We sampled house sparrows (N = 1820) from 58 locations on 6 continents. All the samples were tested using PCR-based methods; blood films from the PCR-positive birds were examined microscopically to identify parasite species. The results show that haemosporidian parasites in the house sparrows' native range are replaced by species from local host-generalist parasite fauna in the alien environments of North and South America. Furthermore, sparrows in colonized regions displayed a lower diversity and prevalence of parasite infections. Because the house sparrow lost its native parasites when colonizing the American continents, the release from these natural enemies may have facilitated its invasion in the last two centuries. Our findings therefore reject the Novel Weapon Hypothesis and are concordant with the Enemy Release Hypothesis.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Island invasion by a threatened tree species: evidence for natural enemy release of mahogany (Swietenia macrophylla) on Dominica, Lesser Antilles
Abstract: Despite its appeal to explain plant invasions, the enemy release hypothesis (ERH) remains largely unexplored for tropical forest trees. Even scarcer are ERH studies conducted on the same host species at both the community and biogeographical scale, irrespective of the system or plant life form. In Cabrits National Park, Dominica, we observed patterns consistent with enemy release of two introduced, congeneric mahogany species, Swietenia macrophylla and S. mahagoni, planted almost 50 years ago. Swietenia populations at Cabrits have reproduced, with S. macrophylla juveniles established in and out of plantation areas at densities much higher than observed in its native range. Swietenia macrophylla juveniles also experienced significantly lower leaf-level herbivory (∼3.0%) than nine co-occurring species native to Dominica (8.4–21.8%), and far lower than conspecific herbivory observed in its native range (11%–43%, on average). These complimentary findings at multiple scales support ERH, and confirm that Swietenia has naturalized at Cabrits. However, Swietenia abundance was positively correlated with native plant diversity at the seedling stage, and only marginally negatively correlated with native plant abundance for stems ≥1-cm dbh. Taken together, these descriptive patterns point to relaxed enemy pressure from specialized enemies, specifically the defoliator Steniscadia poliophaea and the shoot-borer Hypsipyla grandella, as a leading explanation for the enhanced recruitment of Swietenia trees documented at Cabrits.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Invading from the garden? A comparison of leaf herbivory for exotic and native plants in natural and ornamental settings
Abstract: Abstract The enemies release hypothesis proposes that exotic species can become invasive by escaping from predators and parasites in their novel environment. Agrawal et al. (Enemy release? An experiment with congeneric plant pairs and diverse above‐ and below‐ground enemies. Ecology, 86, 2979–2989) proposed that areas or times in which damage to introduced species is low provide opportunities for the invasion of native habitat. We tested whether ornamental settings may provide areas with low levels of herbivory for trees and shrubs, potentially facilitating invasion success. First, we compared levels of leaf herbivory among native and exotic species in ornamental and natural settings in Cincinnati, Ohio, United States. In the second study, we compared levels of herbivory for invasive and noninvasive exotic species between natural and ornamental settings. We found lower levels of leaf damage for exotic species than for native species; however, we found no differences in the amount of leaf damage suffered in ornamental or natural settings. Our results do not provide any evidence that ornamental settings afford additional release from herbivory for exotic plant species.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Herbivory by an introduced Asian weevil negatively affects population growth of an invasive Brazilian shrub in Florida
Abstract: The enemy release hypothesis (ERH) is often cited to explain why some plants successfully invade natural communities while others do not. This hypothesis maintains that plant populations are regulated by coevolved enemies in their native range but are relieved of this pressure where their enemies have not been co-introduced. Some studies have shown that invasive plants sustain lower levels of herbivore damage when compared to native species, but how damage affects fitness and population dynamics remains unclear. We used a system of co-occurring native and invasive Eugenia congeners in south Florida (USA) to experimentally test the ERH, addressing deficiencies in our understanding of the role of natural enemies in plant invasion at the population level. Insecticide was used to experimentally exclude insect herbivores from invasive Eugenia uniflora and its native co-occurring congeners in the field for two years. Herbivore damage, plant growth, survival, and population growth rates for the three species were then compared for control and insecticide-treated plants. Our results contradict the ERH, indicating that E. uniflora sustains more herbivore damage than its native congeners and that this damage negatively impacts stem height, survival, and population growth. In addition, most damage to E. uniflora, a native of Brazil, is carried out by Myllocerus undatus, a recently introduced weevil from Sri Lanka, and M. undatus attacks a significantly greater proportion of E. uniflora leaves than those of its native congeners. This interaction is particularly interesting because M. undatus and E. uniflora share no coevolutionary history, having arisen on two separate continents and come into contact on a third. Our study is the first to document negative population-level effects for an invasive plant as a result of the introduction of a novel herbivore. Such inhibitory interactions are likely to become more prevalent as suites of previously noninteracting species continue to accumulate and new communities assemble worldwide.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Does enemy loss cause release? A biogeographical comparison of parasitoid effects on an introduced insect
Abstract: The loss of natural enemies is a key feature of species introductions and is assumed to facilitate the increased success of species in new locales (enemy release hypothesis; ERH). The ERH is rarely tested experimentally, however, and is often assumed from observations of enemy loss. We provide a rigorous test of the link between enemy loss and enemy release by conducting observational surveys and an in situ parasitoid exclusion experiment in multiple locations in the native and introduced ranges of a gall-forming insect, Neuroterus saltatorius, which was introduced poleward, within North America. Observational surveys revealed that the gall-former experienced increased demographic success and lower parasitoid attack in the introduced range. Also, a different composition of parasitoids attacked the gall-former in the introduced range. These observational results show that enemies were lost and provide support for the ERH. Experimental results, however, revealed that, while some enemy release occurred, it was not the sole driver of demographic success. This was because background mortality in the absence of enemies was higher in the native range than in the introduced range, suggesting that factors other than parasitoids limit the species in its native range and contribute to its success in its introduced range. Our study demonstrates the importance of measuring the effect of enemies in the context of other community interactions in both ranges to understand what factors cause the increased demographic success of introduced species. This case also highlights that species can experience very different dynamics when introduced into ecologically similar communities.
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: The herbivorous arthropods associated with the invasive alien plant, Arundo donax, and the native analogous plant, Phragmites australis, in the Free State Province, South Africa
Abstract: The Enemy Release Hypothesis (ERH) predicts that when plant species are introduced outside their native range there is a release from natural enemies resulting in the plants becoming problematic invasive alien species (Lake & Leishman 2004; Puliafico et al. 2008). The release from natural enemies may benefit alien plants more than simply reducing herbivory because, according to the Evolution of Increased Competitive Ability (EICA) hypothesis, without pressure from herbivores more resources that were previously allocated to defence can be allocated to reproduction (Blossey & Notzold 1995). Alien invasive plants are therefore expected to have simpler herbivore communities with fewer specialist herbivores (Frenzel & Brandl 2003; Heleno et al. 2008; Heger & Jeschke 2014).
Extracted statement — hypothesis: Enemy release
Research field: Ecology and Evolutionary Biology
Title: Escape from parasitism by the invasive alien ladybird, Harmonia axyridis
Abstract: Alien species are often reported to perform better than functionally similar species native to the invaded range, resulting in high population densities, and a tendency to become invasive. The enemy release hypothesis (ERH) explains the success of invasive alien species (IAS) as a consequence of reduced mortality from natural enemies (predators, parasites and pathogens) compared with native species. The harlequin ladybird, Harmonia axyridis, a species alien to Britain, provides a model system for testing the ERH. Pupae of H. axyridis and the native ladybird Coccinella septempunctata were monitored for parasitism between 2008 and 2011, from populations across southern England in areas first invaded by H. axyridis between 2004 and 2009. In addition, a semi‐field experiment was established to investigate the incidence of parasitism of adult H. axyridis and C. septempunctata by Dinocampus coccinellae. Harmonia axyridis pupae were parasitised at a much lower rate than conspecifics in the native range, and both pupae and adults were parasitised at a considerably lower rate than C. septempunctata populations from the same place and time (H. axyridis: 1.67%; C. septempunctata: 18.02%) or in previous studies on Asian H. axyridis (2–7%). We found no evidence that the presence of H. axyridis affected the parasitism rate of C. septempunctata by D. coccinellae. Our results are consistent with the general prediction that the prevalence of natural enemies is lower for introduced species than for native species at early stages of invasion. This may partly explain why H. axyridis is such a successful IAS.
Extracted statement — hypothesis: Enemy release