Moussab/ORKG-training-evaluation-set huggingface dataset:
Research field: Ecology and Evolutionary Biology
Title: Species composition and diversity affect grassland susceptibility and response to invasion
Abstract: In a microcosm experiment, I tested how species composition, species rich- ness, and community age affect the susceptibility of grassland communities to invasion by a noxious weed (Centaurea solstitialis L.). I also examined how these factors influenced Centaurea's impact on the rest of the plant community. When grown in monoculture, eight species found in California's grasslands differed widely in their ability to suppress Centaurea growth. The most effective competitor in monoculture was Hemizonia congesta ssp. Iuzulifolia, which, like Centaurea, is a summer- active annual forb. On average, Centaurea growth decreased as the species richness of communities increased. However, no polyculture suppressed Centaurea growth more than the monoculture of Hemizonia. Centaurea generally made up a smaller proportion of com- munity biomass in newly created ("new") microcosms than in older ("established") mi- crocosms, largely because Centaurea's competitors were more productive in the new treat- ment. Measures of complementarity suggest that Centaurea partitioned resources with an- nual grasses in the new microcosms. This resource partitioning may help to explain Cen- taurea's great success in western North American grasslands. Centaurea strongly suppressed growth of some species but hardly affected others. An- nual grasses were the least affected species in the new monocultures, and perennial grasses were among the least affected species in the established monocultures. In the new micro- cosms, Centaurea's suppression of competing species marginally abated with increasing species richness. This trend was a consequence of the declining success of Centaurea in species-rich communities, rather than a change in the vulnerability of these communities to suppression by a given amount of the invader. The impact of the invader was not related to species richness in the-established microcosms. The results of this study suggest that, at the neighborhood level, diversity can limit invasibility and may reduce the impact of an invader.
Extracted statement — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: OVERLAP OF FOOD AND MICROHABITAT PREFERENCES AMONG SOME NATIVE AND NONNATIVE SLUGS IN MID-ATLANTIC FORESTS OF EASTERN NORTH AMERICA
Abstract: Introduced competitors do not share an evolutionary history that would promote coexistence mechanisms, i.e. niche partitioning. Thus, nonnative species can harm a trophically similar native species by competing with them more intensely than other native species. However, nonnative species may only be able initially to invade habitats in which resource overlap with native species is small. The nonnative slug Arion subfuscus exists in close sympatry with the native philomycid slugs Philomycus carolinianus and Megapallifera mutabilis in central Maryland forests. Resource use by most terrestrial gastropods is poorly known, but seems to suggest high dietary and macrohabitat overlap, potentially placing native gastropod species at high risk of competitive pressure from invading species. However, A. subfuscus was introduced to North America 150 years ago, supporting the possibility that A. subfuscus initially entered an empty niche. We tested the hypothesis that P. carolinianus and M. mutabilis would exhibit greater overlap in food and microhabitat use with A. subfuscus than they would with each other. We established food preferences by examining the faecal material of wild-caught slugs, distinguishing food types and quantifying them by volume on a microgrid. We determined microhabitat preferences by surveying the substrates of slugs in the field. The overlap in substrate and food resources was greater between A. subfuscus and P. carolinianus than between the two native species. However, substrate choice was correlated with local substrate availability for P. carolinianus, suggesting flexibility in habitat use, and the slight overlap in food use between A. subfuscus and P. carolinianus may be low enough to minimize competition.
Extracted statement — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: Norway maple displays greater seasonal growth and phenotypic plasticity to light than native sugar maple
Abstract: Norway maple (Acer platanoides L), which is among the most invasive tree species in forests of eastern North America, is associated with reduced regeneration of the related native species, sugar maple (Acer saccharum Marsh) and other native flora. To identify traits conferring an advantage to Norway maple, we grew both species through an entire growing season under simulated light regimes mimicking a closed forest understorey vs. a canopy disturbance (gap). Dynamic shade-houses providing a succession of high-intensity direct-light events between longer periods of low, diffuse light were used to simulate the light regimes. We assessed seedling height growth three times in the season, as well as stem diameter, maximum photosynthetic capacity, biomass allocation above- and below-ground, seasonal phenology and phenotypic plasticity. Given the north European provenance of Norway maple, we also investigated the possibility that its growth in North America might be increased by delayed fall senescence. We found that Norway maple had significantly greater photosynthetic capacity in both light regimes and grew larger in stem diameter than sugar maple. The differences in below- and above-ground biomass, stem diameter, height and maximum photosynthesis were especially important in the simulated gap where Norway maple continued extension growth during the late fall. In the gap regime sugar maple had a significantly higher root : shoot ratio that could confer an advantage in the deepest shade of closed understorey and under water stress or browsing pressure. Norway maple is especially invasive following canopy disturbance where the opposite (low root : shoot ratio) could confer a competitive advantage. Considering the effects of global change in extending the potential growing season, we anticipate that the invasiveness of Norway maple will increase in the future.
Extracted statement — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: Phenotypic Plasticity and Population Differentiation in an Ongoing Species Invasion
Abstract: The ability to succeed in diverse conditions is a key factor allowing introduced species to successfully invade and spread across new areas. Two non-exclusive factors have been suggested to promote this ability: adaptive phenotypic plasticity of individuals, and the evolution of locally adapted populations in the new range. We investigated these individual and population-level factors in Polygonum cespitosum, an Asian annual that has recently become invasive in northeastern North America. We characterized individual fitness, life-history, and functional plasticity in response to two contrasting glasshouse habitat treatments (full sun/dry soil and understory shade/moist soil) in 165 genotypes sampled from nine geographically separate populations representing the range of light and soil moisture conditions the species inhabits in this region. Polygonum cespitosum genotypes from these introduced-range populations expressed broadly similar plasticity patterns. In response to full sun, dry conditions, genotypes from all populations increased photosynthetic rate, water use efficiency, and allocation to root tissues, dramatically increasing reproductive fitness compared to phenotypes expressed in simulated understory shade. Although there were subtle among-population differences in mean trait values as well as in the slope of plastic responses, these population differences did not reflect local adaptation to environmental conditions measured at the population sites of origin. Instead, certain populations expressed higher fitness in both glasshouse habitat treatments. We also compared the introduced-range populations to a single population from the native Asian range, and found that the native population had delayed phenology, limited functional plasticity, and lower fitness in both experimental environments compared with the introduced-range populations. Our results indicate that the future spread of P. cespitosum in its introduced range will likely be fueled by populations consisting of individuals able to express high fitness across diverse light and moisture conditions, rather than by the evolution of locally specialized populations.
Extracted statement — Continent: North America
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 — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: High temperature tolerance and thermal plasticity in emerald ash borer Agrilus planipennis
Abstract: 1 The emerald ash borer Agrilus planipennis (Coleoptera: Buprestidae) (EAB), an invasive wood‐boring beetle, has recently caused significant losses of native ash (Fraxinus spp.) trees in North America. Movement of wood products has facilitated EAB spread, and heat sanitation of wooden materials according to International Standards for Phytosanitary Measures No. 15 (ISPM 15) is used to prevent this. 2 In the present study, we assessed the thermal conditions experienced during a typical heat‐treatment at a facility using protocols for pallet wood treatment under policy PI‐07, as implemented in Canada. The basal high temperature tolerance of EAB larvae and pupae was determined, and the observed heating rates were used to investigate whether the heat shock response and expression of heat shock proteins occurred in fourth‐instar larvae. 3 The temperature regime during heat treatment greatly exceeded the ISPM 15 requirements of 56 °C for 30 min. Emerald ash borer larvae were highly tolerant of elevated temperatures, with some instars surviving exposure to 53 °C without any heat pre‐treatments. High temperature survival was increased by either slow warming or pre‐exposure to elevated temperatures and a recovery regime that was accompanied by up‐regulated hsp70 expression under some of these conditions. 4 Because EAB is highly heat tolerant and exhibits a fully functional heat shock response, we conclude that greater survival than measured in vitro is possible under industry treatment conditions (with the larvae still embedded in the wood). We propose that the phenotypic plasticity of EAB may lead to high temperature tolerance very close to conditions experienced in an ISPM 15 standard treatment.
Extracted statement — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: VARIATION IN PHENOTYPIC PLASTICITY AMONG NATIVE AND INVASIVE POPULATIONS OF ALLIARIA PETIOLATA
Abstract: Alliaria petiolata is a Eurasian biennial herb that is invasive in North America and for which phenotypic plasticity has been noted as a potentially important invasive trait. Using four European and four North American populations, we explored variation among populations in the response of a suite of antioxidant, antiherbivore, and morphological traits to the availability of water and nutrients and to jasmonic acid treatment. Multivariate analyses revealed substantial variation among populations in mean levels of these traits and in the response of this suite of traits to environmental variation, especially water availability. Univariate analyses revealed variation in plasticity among populations in the expression of all of the traits measured to at least one of these environmental factors, with the exception of leaf length. There was no evidence for continentally distinct plasticity patterns, but there was ample evidence for variation in phenotypic plasticity among the populations within continents. This implies that A. petiolata has the potential to evolve distinct phenotypic plasticity patterns within populations but that invasive populations are no more plastic than native populations.
Extracted statement — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: Developmental plasticity of shell morphology of quagga mussels from shallow and deep-water habitats of the Great Lakes 
Abstract: SUMMARY The invasive zebra mussel (Dreissena polymorpha) has quickly colonized shallow-water habitats in the North American Great Lakes since the 1980s but the quagga mussel (Dreissena bugensis) is becoming dominant in both shallow and deep-water habitats. While quagga mussel shell morphology differs between shallow and deep habitats, functional causes and consequences of such difference are unknown. We examined whether quagga mussel shell morphology could be induced by three environmental variables through developmental plasticity. We predicted that shallow-water conditions (high temperature, food quantity, water motion) would yield a morphotype typical of wild quagga mussels from shallow habitats, while deep-water conditions (low temperature, food quantity, water motion) would yield a morphotype present in deep habitats. We tested this prediction by examining shell morphology and growth rate of quagga mussels collected from shallow and deep habitats and reared under common-garden treatments that manipulated the three variables. Shell morphology was quantified using the polar moment of inertia. Of the variables tested, temperature had the greatest effect on shell morphology. Higher temperature (∼18–20°C) yielded a morphotype typical of wild shallow mussels regardless of the levels of food quantity or water motion. In contrast, lower temperature (∼6–8°C) yielded a morphotype approaching that of wild deep mussels. If shell morphology has functional consequences in particular habitats, a plastic response might confer quagga mussels with a greater ability than zebra mussels to colonize a wider range of habitats within the Great Lakes.
Extracted statement — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: Inducible defences as key adaptations for the successful invasion of Daphnia lumholtzi in North America?
Abstract: The mechanisms underlying successful biological invasions often remain unclear. In the case of the tropical water flea Daphnia lumholtzi, which invaded North America, it has been suggested that this species possesses a high thermal tolerance, which in the course of global climate change promotes its establishment and rapid spread. However, D. lumholtzi has an additional remarkable feature: it is the only water flea that forms rigid head spines in response to chemicals released in the presence of fishes. These morphologically (phenotypically) plastic traits serve as an inducible defence against these predators. Here, we show in controlled mesocosm experiments that the native North American species Daphnia pulicaria is competitively superior to D. lumholtzi in the absence of predators. However, in the presence of fish predation the invasive species formed its defences and became dominant. This observation of a predator-mediated switch in dominance suggests that the inducible defence against fish predation may represent a key adaptation for the invasion success of D. lumholtzi.
Extracted statement — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: Phenotypic plasticity of native vs. invasive purple loosestrife: A two-state multivariate approach
Abstract: The differences in phenotypic plasticity between invasive (North American) and native (German) provenances of the invasive plant Lythrum salicaria (purple loosestrife) were examined using a multivariate reaction norm approach testing two important attributes of reaction norms described by multivariate vectors of phenotypic change: the magnitude and direction of mean trait differences between environments. Data were collected for six life history traits from native and invasive plants using a split-plot design with experimentally manipulated water and nutrient levels. We found significant differences between native and invasive plants in multivariate phenotypic plasticity for comparisons between low and high water treatments within low nutrient levels, between low and high nutrient levels within high water treatments, and for comparisons that included both a water and nutrient level change. The significant genotype x environment (G x E) effects support the argument that invasiveness of purple loosestrife is closely associated with the interaction of high levels of soil nutrient and flooding water regime. Our results indicate that native and invasive plants take different strategies for growth and reproduction; native plants flowered earlier and allocated more to flower production, while invasive plants exhibited an extended period of vegetative growth before flowering to increase height and allocation to clonal reproduction, which may contribute to increased fitness and invasiveness in subsequent years.
Extracted statement — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: Predator-induced phenotypic plasticity in the exotic cladoceran Daphnia lumholtzi
Abstract: Summary 1. The exotic cladoceran Daphnia lumholtzi has recently invaded freshwater systems throughout the United States. Daphnia lumholtzi possesses extravagant head spines that are longer than those found on any other North American Daphnia. These spines are effective at reducing predation from many of the predators that are native to newly invaded habitats; however, they are plastic both in nature and in laboratory cultures. The purpose of this experiment was to better understand what environmental cues induce and maintain these effective predator-deterrent spines. We conducted life-table experiments on individual D. lumholtzi grown in water conditioned with an invertebrate insect predator, Chaoborus punctipennis, and water conditioned with a vertebrate fish predator, Lepomis macrochirus. 2. Daphnia lumholtzi exhibited morphological plasticity in response to kairomones released by both predators. However, direct exposure to predator kairomones during postembryonic development did not induce long spines in D. lumholtzi. In contrast, neonates produced from individuals exposed to Lepomis kairomones had significantly longer head and tail spines than neonates produced from control and Chaoborus individuals. These results suggest that there may be a maternal, or pre-embryonic, effect of kairomone exposure on spine development in D. lumholtzi. 3. Independent of these morphological shifts, D. lumholtzi also exhibited plasticity in life history characteristics in response to predator kairomones. For example, D. lumholtzi exhibited delayed reproduction in response to Chaoborus kairomones, and significantly more individuals produced resting eggs, or ephippia, in the presence of Lepomis kairomones.
Extracted statement — Continent: North America
Research field: Ecology and Evolutionary Biology
Title: Contingency of grassland restoration on year, site, and competition from introduced grasses
Abstract: Semiarid ecosystems such as grasslands are characterized by high temporal variability in abiotic factors, which has led to suggestions that management actions may be more effective in some years than others. Here we examine this hypothesis in the context of grassland restoration, which faces two major obstacles: the contingency of native grass establishment on unpredictable precipitation, and competition from introduced species. We established replicated restoration experiments over three years at two sites in the northern Great Plains in order to examine the extent to which the success of several restoration strategies varied between sites and among years. We worked in 50-yr-old stands of crested wheatgrass (Agropyron cristatum), an introduced perennial grass that has been planted on >10 × 106 ha in western North America. Establishment of native grasses was highly contingent on local conditions, varying fourfold among years and threefold between sites. Survivorship also varied greatly and increased signi...
Extracted statement — Continent: North America