Moussab/ORKG-training-evaluation-set huggingface dataset:
Research field: Ecology and Evolutionary Biology
Title: Experimental invasion by legumes reveals non-random assembly rules in grassland communities
Abstract: 1 Although experimental studies usually reveal that resistance to invasion increases with species diversity, observational studies sometimes show the opposite trend. The higher resistance of diverse plots to invasion may be partly due to the increased probability of a plot containing a species with similar resource requirements to the invader. 2 We conducted a study of the invasibility of monocultures belonging to three different functional groups by seven sown species of legume. By only using experimentally established monocultures, rather than manipulating the abundance of particular functional groups, we removed both species diversity and differences in underlying abiotic conditions as potentially confounding variables. 3 We found that legume monocultures were more resistant than monocultures of grasses or non‐leguminous forbs to invasion by sown legumes but not to invasion by other unsown species. The functional group effect remained after controlling for differences in total biomass and the average height of the above‐ground biomass. 4 The relative success of legume species and types also varied with monoculture characteristics. The proportional biomass of climbing legumes increased strongly with biomass height in non‐leguminous forb monocultures, while it declined with biomass height in grass monocultures. Trifolium pratense was the most successful invader in grass monocultures, while Vicia cracca was the most successful in non‐leguminous forb monocultures. 5 Our results suggest that non‐random assembly rules operate in grassland communities both between and within functional groups. Legume invaders found it much more difficult to invade legume plots, while grass and non‐leguminous forb plots favoured non‐climbing and climbing legumes, respectively. If plots mimic monospecific patches, the effect of these assembly rules in diverse communities might depend upon the patch structure of diverse communities. This dependency on patch structure may contribute to differences in results of research from experimental vs. natural communities.
Extracted statement — Measure of species similarity: Functional groups
Research field: Ecology and Evolutionary Biology
Title: Testing Fox's assembly rule: does plant invasion depend on recipient community structure?
Abstract: Fox's assembly rule, that relative dearth of certain functional groups in a community will facilitate invasion of that particular functional group, serves as the basis for investigation into the functional group effects of invasion resistance. We explored resistance to plant invaders by eliminating or decreasing the number of understory plant species in particular functional groups from plots at a riparian site in southwestern Virginia, USA. Our functional groups comprise combinations of aboveground biomass and rooting structure type. Manipulated plots were planted with 10 randomly chosen species from widespread native and introduced plants commonly found throughout the floodplains of Big Stony Creek. We assessed success of an invasion by plant survivorship and growth. We analyzed survivorship of functional groups with loglinear models for the analysis of categorical data in a 4-way table. There was a significant interaction between functional groups removed in a plot and survivorship in the functional groups added to that plot. However, survivorship of species in functional groups introduced into plots with their respective functional group removed did not differ from survivorship when any other functional group was removed. Additionally, growth of each of the most abundant species did not differ significantly among plots with different functional groups manipulated. Specifically, species did not fare better in those plots that had representatives of their own functional group removed. Fox's assembly rule does not hold for these functional groups in this plant community; however, composition of the recipient community is a significant factor in community assembly.
Extracted statement — Measure of species similarity: Functional groups
Research field: Ecology and Evolutionary Biology
Title: The role of diversity and functional traits of species in community invasibility
Abstract: The invasion of exotic species into assemblages of native plants is a pervasive and widespread phenomenon. Many theoretical and observational studies suggest that diverse communities are more resistant to invasion by exotic species than less diverse ones. However, experimental results do not always support such a relationship. Therefore, the hypothesis of diversity-community invasibility is still a focus of controversy in the field of invasion ecology. In this study, we established and manipulated communities with different species diversity and different species functional groups (16 species belong to C3, C4, forbs and legumes, respectively) to test Elton's hypothesis and other relevant hypotheses by studying the process of invasion. Alligator weed (Alternanthera philoxeroides) was chosen as the invader. We found that the correlation between the decrement of extractable soil nitrogen and biomass of alligator weed was not significant, and that species diversity, independent of functional groups diversity, did not show a significant correlation with invasibility. However, the communities with higher functional groups diversity significantly reduced the biomass of alligator weed by decreasing its resource opportunity. Functional traits of species also influenced the success of the invasion. Alternanthera sessilis, in the same morphological and functional group as alligator weed, was significantly resistant to alligator weed invasion. Because community invasibility is influenced by many factors and interactions among them, the pattern and mechanisms of community invasibility are likely to be far subtler than we found in this study. More careful manipulated experiments coupled with theoretical modeling studies are essential steps to a more profound understanding of community invasibility.
Extracted statement — Measure of species similarity: Functional groups
Research field: Ecology and Evolutionary Biology
Title: Plant functional group identity and diversity determine biotic resistance to invasion by an exotic grass
Abstract: Biotic resistance, the ability of species in a community to limit invasion, is central to our understanding of how communities at risk of invasion assemble after disturbances, but it has yet to translate into guiding principles for the restoration of invasion‐resistant plant communities. We combined experimental, functional, and modelling approaches to investigate processes of community assembly contributing to biotic resistance to an introduced lineage of Phragmites australis, a model invasive species in North America. We hypothesized that (i) functional group identity would be a good predictor of biotic resistance to P. australis, while species identity effect would be redundant within functional group (ii) mixtures of species would be more invasion resistant than monocultures. We classified 36 resident wetland plants into four functional groups based on eight functional traits. We conducted two competition experiments based on the additive competition design with P. australis and monocultures or mixtures of wetland plants. As an indicator of biotic resistance, we calculated a relative competition index (RCIavg) based on the average performance of P. australis in competition treatment compared with control. To explain diversity effect further, we partitioned it into selection effect and complementarity effect and tested several diversity–interaction models. In monoculture treatments, RCIavg of wetland plants was significantly different among functional groups, but not within each functional group. We found the highest RCIavg for fast‐growing annuals, suggesting priority effect. RCIavg of wetland plants was significantly greater in mixture than in monoculture mainly due to complementarity–diversity effect among functional groups. In diversity–interaction models, species interaction patterns in mixtures were described best by interactions between functional groups when fitted to RCIavg or biomass, implying niche partitioning. Synthesis. Functional group identity and diversity of resident plant communities are good indicators of biotic resistance to invasion by introduced Phragmites australis, suggesting niche pre‐emption (priority effect) and niche partitioning (diversity effect) as underlying mechanisms. Guiding principles to understand and/or manage biological invasion could emerge from advances in community theory and the use of a functional framework. Targeting widely distributed invasive plants in different contexts and scaling up to field situations will facilitate generalization.
Extracted statement — Measure of species similarity: Functional traits
Research field: Ecology and Evolutionary Biology
Title: Variation in resource acquisition and utilization traits between native and invasive perennial forbs
Abstract: Understanding the functional traits that allow invasives to outperform natives is a necessary first step in improving our ability to predict and manage the spread of invaders. In nutrient-limited systems, plant competitive ability is expected to be closely tied to the ability of a plant to exploit nutrient-rich microsites and use these captured nutrients efficiently. The broad objective of this work was to compare the ability of native and invasive perennial forbs to acquire and use nutrients from nutrient-rich microsites. We evaluated morphological and physiological responses among four native and four invasive species exposed to heterogeneous (patch) or homogeneous (control) nutrient distribution. Invasives, on average, allocated more biomass to roots and allocated proportionately more root length to nutrient-rich microsites than did natives. Invasives also had higher leaf N, photosynthetic rates, and photosynthetic nitrogen use efficiency than natives, regardless of treatment. While these results suggest multiple traits may contribute to the success of invasive forbs in low-nutrient environments, we also observed large variation in these traits among native forbs. These observations support the idea that functional trait variation in the plant community may be a better predictor of invasion resistance than the functional group composition of the plant community.
Extracted statement — Measure of species similarity: Functional traits
Research field: Ecology and Evolutionary Biology
Title: Functional differences between alien and native species: do biotic interactions determine the functional structure of highly invaded grasslands?
Abstract: Summary 1. Although observed functional differences between alien and native plant species support the idea that invasions are favoured by niche differentiation (ND), when considering invasions along large ecological gradients, habitat filtering (HF) has been proposed to constrain alien species such that they exhibit similar trait values to natives. 2. To reconcile these contrasting observations, we used a multiscale approach using plant functional traits to evaluate how biotic interactions with native species and grazing might determine the functional structure of highly invaded grasslands along an elevation gradient in New Zealand. 3. At a regional scale, functional differences between alien and native plant species translated into nonrandom community assembly and high ND. Alien and native species showed contrasting responses to elevation and the degree of ND between them decreased as elevation increased, suggesting a role for HF. At the plant-neighbourhood scale, species with contrasting traits were generally spatially segregated, highlighting the impact of biotic interactions in structuring local plant communities. A confirmatory multilevel path analysis showed that the effect of elevation and grazing was moderated by the presence of native species, which in turn influenced the local abundance of alien species. 4. Our study showed that functional differences between aliens and natives are fundamental to understand the interplay between multiple mechanisms driving alien species success and their coexistence with natives. In particular, the success of alien species is driven by the presence of native species which can have a negative (biotic resistance) or a positive (facilitation) effect depending on the functional identity of alien species.
Extracted statement — Measure of species similarity: Functional traits
Research field: Ecology and Evolutionary Biology
Title: Major morphological changes in a Lake Victoria cichlid fish within two decades
Abstract: During the upsurge of the introduced predatory Nile perch in Lake Victoria in the 1980s, the zooplanktivorous Haplochromis (Yssichromis) pyrrhocephalus nearly vanished. The species recovered coincident with the intense fishing of Nile perch in the 1990s, when water clarity and dissolved oxygen levels had decreased dramatically due to increased eutrophication. In response to the hypoxic conditions, total gill surface in resurgent H. pyrrhocephalus increased by 64%. Remarkably, head length, eye length, and head volume decreased in size, whereas cheek depth increased. Reductions in eye size and depth of the rostral part of the musculus sternohyoideus, and reallocation of space between the opercular and suspensorial compartments of the head may have permitted accommodation of larger gills in a smaller head. By contrast, the musculus levator posterior, located dorsal to the gills, increased in depth. This probably reflects an adaptive response to the larger and tougher prey types in the diet of resurgent H. pyrrhocephalus. These striking morphological changes over a time span of only two decades could be the combined result of phenotypic plasticity and genetic change and may have fostered recovery of this species.
Extracted statement — Species name: Haplochromis (Yssichromis) pyrrhocephalus
Research field: Ecology and Evolutionary Biology
Title: Phenotypic variability in Holcus lanatus L. in southern Chile: a strategy that enhances plant survival and pasture stability
Abstract: <jats:p>

Holcus lanatus L. can colonise a wide range of sites within the naturalised grassland of the Humid Dominion of Chile. The objectives were to determine plant growth mechanisms and strategies that have allowed H. lanatus to colonise contrasting pastures and to determine the existence of ecotypes of H. lanatus in southern Chile. Plants of H. lanatus were collected from four geographic zones of southern Chile and established in a randomised complete block design with four replicates. Five newly emerging tillers were marked per plant and evaluated at the vegetative, pre-ear emergence, complete emerged inflorescence, end of flowering period, and mature seed stages. At each evaluation, one marked tiller was harvested per plant. The variables measured included lamina length and width, tiller height, length of the inflorescence, total number of leaves, and leaf, stem, and inflorescence mass. At each phenological stage, groups of accessions were statistically formed using cluster analysis. The grouping of accessions (cluster analysis) into statistically different groups (ANOVA and canonical variate analysis) indicated the existence of different ecotypes. The phenotypic variation within each group of the accessions suggested that each group has its own phenotypic plasticity. It is concluded that the successful colonisation by H. lanatus has resulted from diversity within the species.
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Extracted statement — Species name: Holcus lanatus
Research field: Ecology and Evolutionary Biology
Title: Contrasting plant physiological adaptation to climate in the native and introduced range of Hypericum perforatum
Abstract: Abstract How introduced plants, which may be locally adapted to specific climatic conditions in their native range, cope with the new abiotic conditions that they encounter as exotics is not well understood. In particular, it is unclear what role plasticity versus adaptive evolution plays in enabling exotics to persist under new environmental circumstances in the introduced range. We determined the extent to which native and introduced populations of St. John's Wort (Hypericum perforatum) are genetically differentiated with respect to leaf-level morphological and physiological traits that allow plants to tolerate different climatic conditions. In common gardens in Washington and Spain, and in a greenhouse, we examined clinal variation in percent leaf nitrogen and carbon, leaf δ13C values (as an integrative measure of water use efficiency), specific leaf area (SLA), root and shoot biomass, root/shoot ratio, total leaf area, and leaf area ratio (LAR). As well, we determined whether native European H. perforatum experienced directional selection on leaf-level traits in the introduced range and we compared, across gardens, levels of plasticity in these traits. In field gardens in both Washington and Spain, native populations formed latitudinal clines in percent leaf N. In the greenhouse, native populations formed latitudinal clines in root and shoot biomass and total leaf area, and in the Washington garden only, native populations also exhibited latitudinal clines in percent leaf C and leaf δ13C. Traits that failed to show consistent latitudinal clines instead exhibited significant phenotypic plasticity. Introduced St. John's Wort populations also formed significant or marginally significant latitudinal clines in percent leaf N in Washington and Spain, percent leaf C in Washington, and in root biomass and total leaf area in the greenhouse. In the Washington common garden, there was strong directional selection among European populations for higher percent leaf N and leaf δ13C, but no selection on any other measured trait. The presence of convergent, genetically based latitudinal clines between native and introduced H. perforatum, together with previously published molecular data, suggest that native and exotic genotypes have independently adapted to a broad-scale variation in climate that varies with latitude.
Extracted statement — Species name: Hypericum perforatum
Research field: Ecology and Evolutionary Biology
Title: Global patterns in threats to vertebrates by biological invasions
Abstract: Biological invasions as drivers of biodiversity loss have recently been challenged. Fundamentally, we must know where species that are threatened by invasive alien species (IAS) live, and the degree to which they are threatened. We report the first study linking 1372 vertebrates threatened by more than 200 IAS from the completely revised Global Invasive Species Database. New maps of the vulnerability of threatened vertebrates to IAS permit assessments of whether IAS have a major influence on biodiversity, and if so, which taxonomic groups are threatened and where they are threatened. We found that centres of IAS-threatened vertebrates are concentrated in the Americas, India, Indonesia, Australia and New Zealand. The areas in which IAS-threatened species are located do not fully match the current hotspots of invasions, or the current hotspots of threatened species. The relative importance of biological invasions as drivers of biodiversity loss clearly varies across regions and taxa, and changes over time, with mammals from India, Indonesia, Australia and Europe are increasingly being threatened by IAS. The chytrid fungus primarily threatens amphibians, whereas invasive mammals primarily threaten other vertebrates. The differences in IAS threats between regions and taxa can help efficiently target IAS, which is essential for achieving the Strategic Plan 2020 of the Convention on Biological Diversity.
Extracted statement — Measure of resistance/susceptibility: IAS-threatened species
Research field: Ecology and Evolutionary Biology
Title: Native jewelweed, but not other native species, displays post-invasion trait divergence
Abstract: Invasive exotic plants reduce the diversity of native communities by displacing native species. According to the coexistence theory, native plants are able to coexist with invaders only when their fitness is not significantly smaller than that of the exotics or when they occupy a different niche. It has therefore been hypothesized that the survival of some native species at invaded sites is due to post-invasion evolutionary changes in fitness and/or niche traits. In common garden experiments, we tested whether plants from invaded sites of two native species, Impatiens noli-tangere and Galeopsis speciosa, outperform conspecifics from non-invaded sites when grown in competition with the invader (Impatiens parviflora). We further examined whether the expected superior performance of the plants from the invaded sites is due to changes in the plant size (fitness proxy) and/or changes in the germination phenology and phenotypic plasticity (niche proxies). Invasion history did not influence the performance of any native species when grown with the exotic competitor. In I. noli-tangere, however, we found significant trait divergence with regard to plant size, germination phenology and phenotypic plasticity. In the absence of a competitor, plants of I. noli-tangere from invaded sites were larger than plants from non-invaded sites. The former plants germinated earlier than inexperienced conspecifics or an exotic congener. Invasion experience was also associated with increased phenotypic plasticity and an improved shade-avoidance syndrome. Although these changes indicate fitness and niche differentiation of I. noli-tangere at invaded sites, future research should examine more closely the adaptive value of these changes and their genetic basis.
Extracted statement — Species name: Impatiens parviflora
Research field: Ecology and Evolutionary Biology
Title: Ecological traits of the amphipod invader Dikerogammarus villosus on a mesohabitat scale
Abstract: Since 1995, Dikerogammarus villosus Sowinski, a Ponto-Caspian amphi- pod species, has been invading most of Western Europe' s hydrosystems. D. villosus geographic extension and quickly increasing population density has enabled it to become a major component of macrobenthic assemblages in recipient ecosystems. The ecological characteristics of D. villosus on a mesohabitat scale were investigated at a station in the Moselle River. This amphipod is able to colonize a wide range of sub- stratum types, thus posing a threat to all freshwater ecosystems. Rivers whose domi- nant substratum is cobbles and which have tree roots along the banks could harbour particularly high densities of D. villosus. A relationship exists between substratum par- ticle size and the length of the individuals, and spatial segregation according to length was shown. This allows the species to limit intra-specific competition between genera- tions while facilitating reproduction. A strong association exists between D. villosus and other Ponto-Caspian species, such as Dreissena polymorpha and Corophium cur- vispinum, in keeping with Invasional Meltdown Theory. Four taxa (Coenagrionidae, Calopteryx splendens, Corophium curvispinum and Gammarus pulex ) exhibited spa- tial niches that overlap significantly that of D. villosus. According to the predatory be- haviour of the newcomer, their populations may be severely impacted.
Extracted statement — hypothesis: Invasional meltdown