Moussab/ORKG-training-evaluation-set huggingface dataset:
Research field: Ecology and Evolutionary Biology
Title: When there is no escape: The effects of natural enemies on native, invasive, and noninvasive plants
Abstract: An important question in the study of biological invasions is the degree to which successful invasion can be explained by release from control by natural enemies. Natural enemies dominate explanations of two alternate phenomena: that most introduced plants fail to establish viable populations (biotic resistance hypothesis) and that some introduced plants become noxious invaders (natural enemies hypothesis). We used a suite of 18 phylogenetically related native and nonnative clovers (Trifolium and Medicago) and the foliar pathogens and invertebrate herbivores that attack them to answer two questions. Do native species suffer greater attack by natural enemies relative to introduced species at the same site? Are some introduced species excluded from native plant communities because they are susceptible to local natural enemies? We address these questions using three lines of evidence: (1) the frequency of attack and composition of fungal pathogens and herbivores for each clover species in four years of common garden experiments, as well as susceptibility to inoculation with a common pathogen; (2) the degree of leaf damage suffered by each species in common garden experiments; and (3) fitness effects estimated using correlative approaches and pathogen removal experiments. Introduced species showed no evidence of escape from pathogens, being equivalent to native species as a group in terms of infection levels, susceptibility, disease prevalence, disease severity (with more severe damage on introduced species in one year), the influence of disease on mortality, and the effect of fungicide treatment on mortality and biomass. In contrast, invertebrate herbivores caused more damage on native species in two years, although the influence of herbivore attack on mortality did not differ between native and introduced species. Within introduced species, the predictions of the biotic resistance hypothesis were not supported: the most invasive species showed greater infection, greater prevalence and severity of disease, greater prevalence of herbivory, and greater effects of fungicide on biomass and were indistinguishable from noninvasive introduced species in all other respects. Therefore, although herbivores preferred native over introduced species, escape from pest pressure cannot be used to explain why some introduced clovers are common invaders in coastal prairie while others are not.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Soil feedback of exotic savanna grass relates to pathogen absence and mycorrhizal selectivity
Abstract: Enemy release of exotic plants from soil pathogens has been tested by examining plant-soil feedback effects in repetitive growth cycles. However, positive soil feedback may also be due to enhanced benefit from the local arbuscular mycorrhizal fungi (AMF). Few studies actually have tested pathogen effects, and none of them did so in arid savannas. In the Kalahari savanna in Botswana, we compared the soil feedback of the exotic grass Cenchrus biflorus with that of two dominant native grasses, Eragrostis lehmanniana and Aristida meridionalis. The exotic grass had neutral to positive soil feedback, whereas both native grasses showed neutral to negative feedback effects. Isolation and testing of root-inhabiting fungi of E. lehmanniana yielded two host-specific pathogens that did not influence the exotic C. biflorus or the other native grass, A. meridionalis. None of the grasses was affected by the fungi that were isolated from the roots of the exotic C. biflorus. We isolated and compared the AMF community of the native and exotic grasses by polymerase chain reaction-denaturing gradient gel elecrophoresis (PCR-DGGE), targeting AMF 18S rRNA. We used roots from monospecific field stands and from plants grown in pots with mixtures of soils from the monospecific field stands. Three-quarters of the root samples of the exotic grass had two nearly identical sequences, showing 99% similarity with Glomus versiforme. The two native grasses were also associated with distinct bands, but each of these bands occurred in only a fraction of the root samples. The native grasses contained a higher diversity of AMF bands than the exotic grass. Canonical correspondence analyses of the AMF band patterns revealed almost as much difference between the native and exotic grasses as between the native grasses. In conclusion, our results support the hypothesis that release from soil-borne enemies may facilitate local abundance of exotic plants, and we provide the first evidence that these processes may occur in arid savanna ecosystems. Pathogenicity tests implicated the involvement of soil pathogens in the soil feedback responses, and further studies should reveal the functional consequences of the observed high infection with a low diversity of AMF in the roots of exotic plants.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Tolerance to herbivory, and not resistance, may explain differential success of invasive, naturalized, and native North American temperate vines
Abstract: Numerous hypotheses suggest that natural enemies can influence the dynamics of biological invasions. Here, we use a group of 12 related native, invasive, and naturalized vines to test the relative importance of resistance and tolerance to herbivory in promoting biological invasions. In a field experiment in Long Island, New York, we excluded mammal and insect herbivores and examined plant growth and foliar damage over two growing seasons. This novel approach allowed us to compare the relative damage from mammal and insect herbivores and whether damage rates were related to invasion. In a greenhouse experiment, we simulated herbivory through clipping and measured growth response. After two seasons of excluding herbivores, there was no difference in relative growth rates among invasive, naturalized, and native woody vines, and all vines were susceptible to damage from mammal and insect herbivores. Thus, differential attack by herbivores and plant resistance to herbivory did not explain invasion success of these species. In the field, where damage rates were high, none of the vines were able to fully compensate for damage from mammals. However, in the greenhouse, we found that invasive vines were more tolerant of simulated herbivory than native and naturalized relatives. Our results indicate that invasive vines are not escaping herbivory in the novel range, rather they are persisting despite high rates of herbivore damage in the field. While most studies of invasive plants and natural enemies have focused on resistance, this work suggests that tolerance may also play a large role in facilitating invasions.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: The invasive shrub Buddleja davidii performs better in its introduced range
Abstract: It is commonly assumed that invasive plants grow more vigorously in their introduced than in their native range, which is then attributed to release from natural enemies or to microevolutionary changes, or both. However, few studies have tested this assumption by comparing the performance of invasive species in their native vs. introduced ranges. Here, we studied abundance, growth, reproduction, and herbivory in 10 native Chinese and 10 invasive German populations of the invasive shrub Buddleja davidii (Scrophulariaceae; butterfly bush). We found strong evidence for increased plant vigour in the introduced range: plants in invasive populations were significantly taller and had thicker stems, larger inflorescences, and heavier seeds than plants in native populations. These differences in plant performance could not be explained by a more benign climate in the introduced range. Since leaf herbivory was substantially reduced in invasive populations, our data rather suggest that escape from natural enemies, associated with increased plant growth and reproduction, contributes to the invasion success of B. davidii in Central Europe.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Herbivores, but not other insects, are scarce on alien plants
Abstract: Abstract Understanding how the landscape-scale replacement of indigenous plants with alien plants influences ecosystem structure and functioning is critical in a world characterized by increasing biotic homogenization. An important step in this process is to assess the impact on invertebrate communities. Here we analyse insect species richness and abundance in sweep collections from indigenous and alien (Australasian) woody plant species in South Africa's Western Cape. We use phylogenetically relevant comparisons and compare one indigenous with three Australasian alien trees within each of Fabaceae: Mimosoideae, Myrtaceae, and Proteaceae: Grevilleoideae. Although some of the alien species analysed had remarkably high abundances of herbivores, even when intentionally introduced biological control agents are discounted, overall, herbivorous insect assemblages from alien plants were slightly less abundant and less diverse compared with those from indigenous plants – in accordance with predictions from the enemy release hypothesis. However, there were no clear differences in other insect feeding guilds. We conclude that insect assemblages from alien plants are generally quite diverse, and significant differences between these and assemblages from indigenous plants are only evident for herbivorous insects.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Diversity and abundance of arthropod floral visitor and herbivore assemblages on exotic and native Senecio species
Abstract: The enemy release hypothesis predicts that native herbivores prefer native, rather than exotic plants, giving invaders a competitive advantage. In contrast, the biotic resistance hypothesis states that many invaders are prevented from establishing because of competitive interactions, including herbivory, with native fauna and flora. Success or failure of spread and establishment might also be influenced by the presence or absence of mutualists, such as pollinators. Senecio madagascariensis (fireweed), an annual weed from South Africa, inhabits a similar range in Australia to the related native S. pinnatifolius. The aim of this study was to determine, within the context of invasion biology theory, whether the two Senecio species share insect fauna, including floral visitors and herbivores. Surveys were carried out in south-east Queensland on allopatric populations of the two Senecio species, with collected insects identified to morphospecies. Floral visitor assemblages were variable between populations. However, the two Senecio species shared the two most abundant floral visitors, honeybees and hoverflies. Herbivore assemblages, comprising mainly hemipterans of the families Cicadellidae and Miridae, were variable between sites and no patterns could be detected between Senecio species at the morphospecies level. However, when insect assemblages were pooled (i.e. community level analysis), S. pinnatifolius was shown to host a greater total abundance and richness of herbivores. Senecio madagascariensis is unlikely to be constrained by lack of pollinators in its new range and may benefit from lower levels of herbivory compared to its native congener S. pinnatifolius.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Acceleration of Exotic Plant Invasion in a Forested Ecosystem by a Generalist Herbivore
Abstract: Abstract: The successful invasion of exotic plants is often attributed to the absence of coevolved enemies in the introduced range (i.e., the enemy release hypothesis). Nevertheless, several components of this hypothesis, including the role of generalist herbivores, remain relatively unexplored. We used repeated censuses of exclosures and paired controls to investigate the role of a generalist herbivore, white‐tailed deer (Odocoileus virginianus), in the invasion of 3 exotic plant species (Microstegium vimineum, Alliaria petiolata, and Berberis thunbergii) in eastern hemlock (Tsuga canadensis) forests in New Jersey and Pennsylvania (U.S.A.). This work was conducted in 10 eastern hemlock (T. canadensis) forests that spanned gradients in deer density and in the severity of canopy disturbance caused by an introduced insect pest, the hemlock woolly adelgid (Adelges tsugae). We used maximum likelihood estimation and information theoretics to quantify the strength of evidence for alternative models of the influence of deer density and its interaction with the severity of canopy disturbance on exotic plant abundance. Our results were consistent with the enemy release hypothesis in that exotic plants gained a competitive advantage in the presence of generalist herbivores in the introduced range. The abundance of all 3 exotic plants increased significantly more in the control plots than in the paired exclosures. For all species, the inclusion of canopy disturbance parameters resulted in models with substantially greater support than the deer density only models. Our results suggest that white‐tailed deer herbivory can accelerate the invasion of exotic plants and that canopy disturbance can interact with herbivory to magnify the impact. In addition, our results provide compelling evidence of nonlinear relationships between deer density and the impact of herbivory on exotic species abundance. These findings highlight the important role of herbivore density in determining impacts on plant abundance and provide evidence of the operation of multiple mechanisms in exotic plant invasion.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Cryptic seedling herbivory by nocturnal introduced generalists impacts survival, performance of native and exotic plants
Abstract: Although much of the theory on the success of invasive species has been geared at escape from specialist enemies, the impact of introduced generalist invertebrate herbivores on both native and introduced plant species has been underappreciated. The role of nocturnal invertebrate herbivores in structuring plant communities has been examined extensively in Europe, but less so in North America. Many nocturnal generalists (slugs, snails, and earwigs) have been introduced to North America, and 96% of herbivores found during a night census at our California Central Valley site were introduced generalists. We explored the role of these herbivores in the distribution, survivorship, and growth of 12 native and introduced plant species from six families. We predicted that introduced species sharing an evolutionary history with these generalists might be less vulnerable than native plant species. We quantified plant and herbivore abundances within our heterogeneous site and also established herbivore removal experiments in 160 plots spanning the gamut of microhabitats. As 18 collaborators, we checked 2000 seedling sites every day for three weeks to assess nocturnal seedling predation. Laboratory feeding trials allowed us to quantify the palatability of plant species to the two dominant nocturnal herbivores at the site (slugs and earwigs) and allowed us to account for herbivore microhabitat preferences when analyzing attack rates on seedlings. The relationship between local slug abundance and percent cover of five common plant taxa at the field site was significantly negatively associated with the mean palatability of these taxa to slugs in laboratory trials. Moreover, seedling mortality of 12 species in open-field plots was positively correlated with mean palatability of these taxa to both slugs and earwigs in laboratory trials. Counter to expectations, seedlings of native species were neither more vulnerable nor more palatable to nocturnal generalists than those of introduced species. Growth comparison of plants within and outside herbivore exclosures also revealed no differences between native and introduced plant species, despite large impacts of herbivores on growth. Cryptic nocturnal predation on seedlings was common and had large effects on plant establishment at our site. Without intensive monitoring, such predation could easily be misconstrued as poor seedling emergence.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Plant-soil feedback induces shifts in biomass allocation in the invasive plant Chromolaena odorata
Abstract: 1. Soil communities and their interactions with plants may play a major role in determining the success of invasive species. However, rigorous investigations of this idea using cross‐continental comparisons, including native and invasive plant populations, are still scarce.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Release from soil pathogens plays an important role in the success of invasive Carpobrotus in the Mediterranean
Abstract: Introduced plant species can become locally dominant and threaten native flora and fauna. This dominance is often thought to be a result of release from specialist enemies in the invaded range, or the evolution of increased competitive ability. Soil borne microorganisms have often been overlooked as enemies in this context, but a less deleterious plant soil interaction in the invaded range could explain local dominance. Two plant species, Carpobrotus edulis and the hybrid Carpobrotus X cf. acinaciformis, are considered major pests in the Mediterranean basin. We tested if release from soil-borne enemies and/or evolution of increased competitive ability could explain this dominance. Comparing biomass production in non-sterile soil with that in sterilized soil, we found that inoculation with rhizosphere soil from the native range reduced biomass production by 32% while inoculation with rhizosphere soil from the invaded range did not have a significant effect on plant biomass. Genotypes from the invaded range, including a hybrid, did not perform better than plants from the native range in sterile soil. Hence evolution of increased competitive ability and hybridization do not seem to play a major role. We conclude that the reduced negative net impact of the soil community in the invaded range may contribute to the success of Carpobrotus species in the Mediterranean basin. © 2008 SAAB. Published by Elsevier B.V. All rights reserved.
Extracted statement — Investigated species: Plants
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 — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Community structure of insect herbivores on introduced and native Solidago plants in Japan
Abstract: We compared community composition, density, and species richness of herbivorous insects on the introduced plant Solidago altissima L. (Asteraceae) and the related native species Solidago virgaurea L. in Japan. We found large differences in community composition on the two Solidago species. Five hemipteran sap feeders were found only on S. altissima. Two of them, the aphid Uroleucon nigrotuberculatum Olive (Hemiptera: Aphididae) and the scale insect Parasaissetia nigra Nietner (Hemiptera: Coccidae), were exotic species, accounting for 62% of the total individuals on S. altissima. These exotic sap feeders mostly determined the difference of community composition on the two plant species. In contrast, the herbivore community on S. virgaurea consisted predominately of five native insects: two lepidopteran leaf chewers and three dipteran leaf miners. Overall species richness did not differ between the plants because the increased species richness of sap feeders was offset by the decreased richness of leaf chewers and leaf miners on S. altissima. The overall density of herbivorous insects was higher on S. altissima than on S. virgaurea, because of the high density of the two exotic sap feeding species on S. altissima. We discuss the importance of analyzing community composition in terms of feeding guilds of insect herbivores for understanding how communities of insect herbivores are organized on introduced plants in novel habitats.
Extracted statement — Investigated species: Plants
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 — Investigated species: Plants