Moussab/ORKG-training-evaluation-set huggingface dataset:
Research field: Ecology and Evolutionary Biology
Title: Darwin's naturalization hypothesis revisited
Abstract: In The Origin of Species, Darwin (1859) drew attention to observations by Alphonse de Candolle (1855) that floras gain by naturalization far more species belonging to new genera than species belonging to native genera. Darwin (1859, p. 86) goes on to give a specific example: “In the last edition of Dr. Asa Gray’s ‘Manual of the Flora of the United States’ ... out of the 162 naturalised genera, no less than 100 genera are not there indigenous.” Darwin used these data to support his theory of intense competition between congeners, described only a few pages earlier: “As the species of the same genus usually have, though by no means invariably, much similarity in habits and constitution, and always in structure, the struggle will generally be more severe between them” (1859, p. 60). Darwin’s intriguing observations have recently attracted renewed interest, as comprehensive lists of naturalized plants have become available for various regions of the world. Two studies (Mack 1996; Rejmanek 1996, 1998) have concluded that naturalized floras provide some support for Darwin’s hypothesis, but only one of these studies used statistical tests. Analyses of additional floras are needed to test the generality of Darwin’s naturalization hypothesis. Mack (1996) tabulated data from six regional floras within the United States and noted that naturalized species more often belong to alien genera than native genera, with the curious exception of one region (New York). In addition to the possibility of strong competition between native and introduced congeners, Mack (1996) proposed that specialist native herbivores, or pathogens, may be
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Enemy damage of exotic plant species is similar to that of natives and increases with productivity
Abstract: In their colonized ranges, exotic plants may be released from some of the herbivores or pathogens of their home ranges but these can be replaced by novel enemies. It is of basic and practical interest to understand which characteristics of invaded communities control accumulation of the new pests. Key questions are whether enemy load on exotic species is smaller than on native competitors as suggested by the enemy release hypothesis (ERH) and whether this difference is most pronounced in resource‐rich habitats as predicted by the resource–enemy release hypothesis (R‐ERH). In 72 populations of 12 exotic invasive species, we scored all visible above‐ground damage morphotypes caused by herbivores and fungal pathogens. In addition, we quantified levels of leaf herbivory and fruit damage. We then assessed whether variation in damage diversity and levels was explained by habitat fertility, by relatedness between exotic species and the native community or rather by native species diversity. In a second part of the study, we also tested the ERH and the R‐ERH by comparing damage of plants in 28 pairs of co‐occurring native and exotic populations, representing nine congeneric pairs of native and exotic species. In the first part of the study, diversity of damage morphotypes and damage levels of exotic populations were greater in resource‐rich habitats. Co‐occurrence of closely related, native species in the community significantly increased the probability of fruit damage. Herbivory on exotics was less likely in communities with high phylogenetic diversity. In the second part of the study, exotic and native congeneric populations incurred similar damage diversity and levels, irrespective of whether they co‐occurred in nutrient‐poor or nutrient‐rich habitats. Synthesis. We identified habitat productivity as a major community factor affecting accumulation of enemy damage by exotic populations. Similar damage levels in exotic and native congeneric populations, even in species pairs from fertile habitats, suggest that the enemy release hypothesis or the R‐ERH cannot always explain the invasiveness of introduced species.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: How strongly do interactions with closely-related native species influence plant invasions? Darwin's naturalization hypothesis assessed on Mediterranean islands
Abstract: Aim Recent works have found the presence of native congeners to have a small effect on the naturalization rates of introduced plants, some suggesting a negative interaction (as proposed by Charles Darwin in The Origin of Species), and others a positive association. We assessed this question for a new biogeographic region, and discuss some of the problems associated with data base analyses of this type.
Extracted statement — Investigated species: Plants
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 — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Seedling traits, plasticity and local differentiation as strategies of invasive species of Impatiens in central Europe
Abstract: Background and Aims Invasiveness of some alien plants is associated with their traits, plastic responses to environmental conditions and interpopulation differentiation. To obtain insights into the role of these processes in contributing to variation in performance, we compared congeneric species of Impatiens (Balsaminaceae) with different origin and invasion status that occur in central Europe. Methods Native I. noli-tangere and three alien species (highly invasive I. glandulifera, less invasive I. parviflora and potentially invasive I. capensis) were studied and their responses to simulated canopy shading and different nutrient and moisture levels were determined in terms of survival and seedling traits. Key Results and Conclusions Impatiens glandulifera produced high biomass in all the treatments and the control, exhibiting the ‘Jack-and-master’ strategy that makes it a strong competitor from germination onwards. The results suggest that plasticity and differentiation occurred in all the species tested and that along the continuum from plasticity to differentiation, the species at the plasticity end is the better invader. The most invasive species I. glandulifera appears to be highly plastic, whereas the other two less invasive species, I. parviflora and I. capensis, exhibited lower plasticity but rather strong population differentiation. The invasive Impatiens species were taller and exhibited higher plasticity and differentiation than native I. noli-tangere. This suggests that even within one genus, the relative importance of the phenomena contributing to invasiveness appears to be species'specific.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: The relative importance for plant invasiveness of trait means, and their plasticity and integration in a multivariate framework
Abstract: Functional traits, their plasticity and their integration in a phenotype have profound impacts on plant performance. We developed structural equation models (SEMs) to evaluate their relative contribution to promote invasiveness in plants along resource gradients. We compared 20 invasive-native phylogenetically and ecologically related pairs. SEMs included one morphological (root-to-shoot ratio (R/S)) and one physiological (photosynthesis nitrogen-use efficiency (PNUE)) trait, their plasticities in response to nutrient and light variation, and phenotypic integration among 31 traits. Additionally, these components were related to two fitness estimators, biomass and survival. The relative contributions of traits, plasticity and integration were similar in invasive and native species. Trait means were more important than plasticity and integration for fitness. Invasive species showed higher fitness than natives because: they had lower R/S and higher PNUE values across gradients; their higher PNUE plasticity positively influenced biomass and thus survival; and they offset more the cases where plasticity and integration had a negative direct effect on fitness. Our results suggest that invasiveness is promoted by higher values in the fitness hierarchy--trait means are more important than trait plasticity, and plasticity is similar to integration--rather than by a specific combination of the three components of the functional strategy.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Phenotypic Plasticity in the Invasion of Crofton Weed (Eupatorium adenophorum) in China
Abstract: <jats:p>Phenotypic plasticity and rapid evolution are two important strategies by which invasive species adapt to a wide range of environments and consequently are closely associated with plant invasion. To test their importance in invasion success of Crofton weed, we examined the phenotypic response and genetic variation of the weed by conducting a field investigation, common garden experiments, and intersimple sequence repeat (ISSR) marker analysis on 16 populations in China. Molecular markers revealed low genetic variation among and within the sampled populations. There were significant differences in leaf area (LA), specific leaf area (SLA), and seed number (SN) among field populations, and plasticity index (PI<jats:sub>v</jats:sub>) for LA, SLA, and SN were 0.62, 0.46 and 0.85, respectively. Regression analyses revealed a significant quadratic effect of latitude of population origin on LA, SLA, and SN based on field data but not on traits in the common garden experiments (greenhouse and open air). Plants from different populations showed similar reaction norms across the two common gardens for functional traits. LA, SLA, aboveground biomass, plant height at harvest, first flowering day, and life span were higher in the greenhouse than in the open-air garden, whereas SN was lower. Growth conditions (greenhouse vs. open air) and the interactions between growth condition and population origin significantly affect plant traits. The combined evidence suggests high phenotypic plasticity but low genetically based variation for functional traits of Crofton weed in the invaded range. Therefore, we suggest that phenotypic plasticity is the primary strategy for Crofton weed as an aggressive invader that can adapt to diverse environments in China.</jats:p>
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Seedling defoliation, plant growth and flowering potential in native- and invasive-range Plantago lanceolata populations
Abstract: Hanley ME (2012). Seedling defoliation, plant growth and flowering potential in native- and invasive-range Plantago lanceolata populations. Weed Research52, 252–259. Summary The plastic response of weeds to new environmental conditions, in particular the likely relaxation of herbivore pressure, is considered vital for successful colonisation and spread. However, while variation in plant anti-herbivore resistance between native- and introduced-range populations is well studied, few authors have considered herbivore tolerance, especially at the seedling stage. This study examines variation in seedling tolerance in native (European) and introduced (North American) Plantago lanceolata populations following cotyledon removal at 14 days old. Subsequent effects on plant growth were quantified at 35 days, along with effects on flowering potential at maturity. Cotyledon removal reduced early growth for all populations, with no variation between introduced- or native-range plants. Although more variable, the effects of cotyledon loss on flowering potential were also unrelated to range. The likelihood that generalist seedling herbivores are common throughout North America may explain why no difference in seedling tolerance was apparent. However, increased flowering potential in plants from North American P. lanceolata populations was observed. As increased flowering potential was not lost, even after severe cotyledon damage, the manifestation of phenotypic plasticity in weeds at maturity may nonetheless still be shaped by plasticity in the ability to tolerate herbivory during seedling establishment.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Plastic Traits of an Exotic Grass Contribute to Its Abundance but Are Not Always Favourable
Abstract: In herbaceous ecosystems worldwide, biodiversity has been negatively impacted by changed grazing regimes and nutrient enrichment. Altered disturbance regimes are thought to favour invasive species that have a high phenotypic plasticity, although most studies measure plasticity under controlled conditions in the greenhouse and then assume plasticity is an advantage in the field. Here, we compare trait plasticity between three co-occurring, C4 perennial grass species, an invader Eragrostis curvula, and natives Eragrostis sororia and Aristida personata to grazing and fertilizer in a three-year field trial. We measured abundances and several leaf traits known to correlate with strategies used by plants to fix carbon and acquire resources, i.e. specific leaf area (SLA), leaf dry matter content (LDMC), leaf nutrient concentrations (N, C∶N, P), assimilation rates (Amax) and photosynthetic nitrogen use efficiency (PNUE). In the control treatment (grazed only), trait values for SLA, leaf C∶N ratios, Amax and PNUE differed significantly between the three grass species. When trait values were compared across treatments, E. curvula showed higher trait plasticity than the native grasses, and this correlated with an increase in abundance across all but the grazed/fertilized treatment. The native grasses showed little trait plasticity in response to the treatments. Aristida personata decreased significantly in the treatments where E. curvula increased, and E. sororia abundance increased possibly due to increased rainfall and not in response to treatments or invader abundance. Overall, we found that plasticity did not favour an increase in abundance of E. curvula under the grazed/fertilized treatment likely because leaf nutrient contents increased and subsequently its' palatability to consumers. E. curvula also displayed a higher resource use efficiency than the native grasses. These findings suggest resource conditions and disturbance regimes can be manipulated to disadvantage the success of even plastic exotic species.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Multispecies comparison reveals that invasive and native plants differ in their traits but not in their plasticity
Abstract: Summary 1. Plastic responses to spatiotemporal environmental variation strongly influence species distribution, with widespread species expected to have high phenotypic plasticity. Theoretically, high phenotypic plasticity has been linked to plant invasiveness because it facilitates colonization and rapid spreading over large and environmentally heterogeneous new areas. 2. To determine the importance of phenotypic plasticity for plant invasiveness, we compare well-known exotic invasive species with widespread native congeners. First, we characterized the phenotype of 20 invasive–native ecologically and phylogenetically related pairs from the Mediterranean region by measuring 20 different traits involved in resource acquisition, plant competition ability and stress tolerance. Second, we estimated their plasticity across nutrient and light gradients. 3. On average, invasive species had greater capacity for carbon gain and enhanced performance over a range of limiting to saturating resource availabilities than natives. However, both groups responded to environmental variations with high albeit similar levels of trait plasticity. Therefore, contrary to the theory, the extent of phenotypic plasticity was not significantly higher for invasive plants. 4. We argue that the combination of studying mean values of a trait with its plasticity can render insightful conclusions on functional comparisons of species such as those exploring the performance of species coexisting in heterogeneous and changing environments.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Functional differences in response to drought in the invasive Taraxacum officinale from native and introduced alpine habitat ranges
Abstract: Background: Phenotypic plasticity and ecotypic differentiation have been suggested as the main mechanisms by which widely distributed species can colonise broad geographic areas with variable and stressful conditions. Some invasive plant species are among the most widely distributed plants worldwide. Plasticity and local adaptation could be the mechanisms for colonising new areas. Aims: We addressed if Taraxacum officinale from native (Alps) and introduced (Andes) stock responded similarly to drought treatment, in terms of photosynthesis, foliar angle, and flowering time. We also evaluated if ontogeny affected fitness and physiological responses to drought. Methods: We carried out two common garden experiments with both seedlings and adults (F2) of T. officinale from its native and introduced ranges in order to evaluate their plasticity and ecotypic differentiation under a drought treatment. Results: Our data suggest that the functional response of T. officinale individuals from the introduced range to drought is the result of local adaptation rather than plasticity. In addition, the individuals from the native distribution range were more sensitive to drought than those from the introduced distribution ranges at both seedling and adult stages. Conclusions: These results suggest that local adaptation may be a possible mechanism underlying the successful invasion of T. officinale in high mountain environments of the Andes.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Elevational distribution limits of non-native species: combining observational and experimental evidence
Abstract: Background: In temperate mountains, most non-native plant species reach their distributional limit somewhere along the elevational gradient. However, it is unclear if growth limitations can explain upper range limits and whether phenotypic plasticity or genetic changes allow species to occupy a broad elevational gradient. Aims: We investigated how non-native plant individuals from different elevations responded to growing season temperatures, which represented conditions at the core and margin of the elevational distributions of the species. Methods: We recorded the occurrence of nine non-native species in the Swiss Alps and subsequently conducted a climate chamber experiment to assess growth rates of plants from different elevations under different temperature treatments. Results: The elevational limit observed in the field was not related to the species' temperature response in the climate chamber experiment. Almost all species showed a similar level of reduction in growth rates under lower temperatures independent of the upper elevational limit of the species' distribution. For two species we found indications for genetic differentiation among plants from different elevations. Conclusions: We conclude that factors other than growing season temperatures, such as extreme events or winter mortality, might shape the elevational limit of non-native species, and that ecological filtering might select for genotypes that are phenotypically plastic.
Extracted statement — Investigated species: Plants
Research field: Ecology and Evolutionary Biology
Title: Invasion strategies in clonal aquatic plants: are phenotypic differences caused by phenotypic plasticity or local adaptation? 
Abstract: BACKGROUND AND AIMS The successful spread of invasive plants in new environments is often linked to multiple introductions and a diverse gene pool that facilitates local adaptation to variable environmental conditions. For clonal plants, however, phenotypic plasticity may be equally important. Here the primary adaptive strategy in three non-native, clonally reproducing macrophytes (Egeria densa, Elodea canadensis and Lagarosiphon major) in New Zealand freshwaters were examined and an attempt was made to link observed differences in plant morphology to local variation in habitat conditions. METHODS Field populations with a large phenotypic variety were sampled in a range of lakes and streams with different chemical and physical properties. The phenotypic plasticity of the species before and after cultivation was studied in a common garden growth experiment, and the genetic diversity of these same populations was also quantified. KEY RESULTS For all three species, greater variation in plant characteristics was found before they were grown in standardized conditions. Moreover, field populations displayed remarkably little genetic variation and there was little interaction between habitat conditions and plant morphological characteristics. CONCLUSIONS The results indicate that at the current stage of spread into New Zealand, the primary adaptive strategy of these three invasive macrophytes is phenotypic plasticity. However, while limited, the possibility that genetic diversity between populations may facilitate ecotypic differentiation in the future cannot be excluded. These results thus indicate that invasive clonal aquatic plants adapt to new introduced areas by phenotypic plasticity. Inorganic carbon, nitrogen and phosphorous were important in controlling plant size of E. canadensis and L. major, but no other relationships between plant characteristics and habitat conditions were apparent. This implies that within-species differences in plant size can be explained by local nutrient conditions. All together this strongly suggests that invasive clonal aquatic plants adapt to a wide range of habitats in introduced areas by phenotypic plasticity rather than local adaptation.
Extracted statement — Investigated species: Plants