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Simulated migration in a long-term climate change experiment: Invasions impeded by dispersal limitation, not biotic resistance
Abstract
1. Successful poleward shifts of plant species ranges as a result of climate change will depend on interactions between migrating species and the communities they invade. Although poleward migration may be constrained by slow long-distance dispersal into suitable habitat, the invasion resistance of a plant community is expected to depend on the timeframe available for species- and genetic-level compositional shifts.
2. We tested whether range shifts of Bromus erectus and Brachypodium pinnatum, two dominant grasses of calcareous grasslands in the southern UK with different phenologies and competitive abilities, are limited by dispersal and whether local plant communities are able to adapt to changes in climate conditions and resist invasion from novel species. We added seeds of the two species to an infertile grassland in northern England, where both species are currently absent and where winter warming and summer drought have been simulated for short (1 year) and long (15 years) durations.
3. We predicted that seed addition would lead to higher establishment of the two species in grassland plots subjected to artificial winter warming than in plots with imposed summer drought, and we expected that invasion resistance of the extant grassland community would be higher in long-term than in short-term climate manipulations.
4. Warming induced earlier seedling emergence in both species and resulted in higher invader above-ground biomass at the end of the first growing season. Summer drought did not affect the invasion success of Bromus but it offset the beneficial effects of winter warming in Brachypodium. Invader performance was similar in communities with long- and short-term climate manipulations.
5. Synthesis. Climate induced poleward shifts will proceed even if slow long-distance dispersal of migrating species allows extant communities to adapt to a new climate regime. Asynchrony between the phenology of migrating species and seasonal resource use by invaded communities are likely to amplify migration success.
... Temperatures significantly increased and relative humidity significantly decreased (Poniatowski & Fartmann, 2011;Stuhldreher & Fartmann, 2014. Indeed, global warming is known to promote the invasion of B. erectus in calcareous grasslands (Moser et al., 2011). Bromus erectus is well-adapted to drought (Grime et al., 2007); and consequently, it currently germinates earlier in the season due to higher temperatures in spring and can produce more biomass during the year, favouring the expansion of the species (Moser et al., 2011). ...
... Indeed, global warming is known to promote the invasion of B. erectus in calcareous grasslands (Moser et al., 2011). Bromus erectus is well-adapted to drought (Grime et al., 2007); and consequently, it currently germinates earlier in the season due to higher temperatures in spring and can produce more biomass during the year, favouring the expansion of the species (Moser et al., 2011). In the Diemel Valley, the patches dominated by B. erectus are, therefore, restricted to the driest and warmest parts of the study area (T. ...
... Indeed, B. erectus is known to be a tallgrowing grass that produces dense litter layers when abundant (Grime et al., 2007;Steinger et al., 2007;M€ ollenbeck et al., 2009). In particular, less-competitive plant species depending on high light availability suffer from such shady conditions (Fleischer et al., 2013;Streitberger et al., 2017;V ıtov a et al., 2017) resulting in species-poor swards (Steinger et al., 2007;Moser et al., 2011). ...
1. The most common mechanism of biological invasions is an increase in competition, which usually results in the loss of biodiversity. The invasion of Bromus erectus (Syn. Bromopsis erecta) in calcareous grasslands of western and central Europe is well-documented. However, it is largely unknown to what extent this development affects biodiversity.
2. In this study, we analysed the effects of B. erectus invasion on vascular plant and leafhopper assemblages of calcareous grasslands. At each of the 15 randomly selected sites, we compared one plot with stands of Bromus (presence) and one without (absence) (paired sampling design).
3. The invasion of B. erectus affected vegetation structure as well as vascular plant and leafhopper assemblages. Despite similar abiotic site characteristics, Bromus plots had a higher turf height, vegetation density and litter cover. Additionally, we recorded a much lower species richness in Bromus plots than in absence plots in all analysed groups of vascular plants. A similar pattern was found for leafhoppers. Absence plots exhibited a higher species richness of habitat and diet specialists than Bromus plots. The overall abundance of all leafhopper species was highest in presence plots, whereas that of diet specialists peaked in absence plots.
4. We conclude that the ongoing invasion of B. erectus will lead to a strong structural homogenisation with negative effects on plant and insect diversity. One possible management tool might be a goal-driven rough grazing with sheep – especially in spring when B. erectus is much more palatable than in summer and autumn.
... Although its remaining area is small and fragmented, calcareous grasslands host a variety of plant and invertebrate species often restricted to this vegetation type . Several experiments have studied the response of these species-rich communities to environmental change Maalouf et al., 2012;Niklaus and Körner, 2004;Sternberg et al., 1999) but the potential of their dominant species to migrate and colonise more northern communities under changing climatic conditions has been rarely addressed (Buckland et al., 2001;Moser et al., 2011). How dispersal is affected by climate may not only determine migration rates of individual species but also influence their capacity to establish in new habitats (Randle et al., 2009) and transform the invaded communities (Gilman et al., 2010). ...
... obs.). Seed addition experiments showed that both species are able to establish outside their current distribution range (Buckland et al., 2001;Moser et al., 2011), which suggests that the observed infertility of edge populations is due to either temperature limited seed production or self-incompatibility. If seed production of B. pinnatum and B. erecta is indeed temperature limited, climate warming will enable them to spread and colonise new suitable habitat at their northern range limit, which may pose a threat to the diversity of northern calcareous grasslands not yet colonised by the two species. ...
... Low temperatures and frost limit plant growth (Despland and Houle, 1997;Woodward, 1990), but experiments have shown that in some species reproduction rather than growth is constrained outside their current distribution range (Griffith and Watson, 2006). For instance, B. erecta and B. pinnatum were both able to establish beyond their elevational range limit in the Peak District, UK, once seeds were added to an extant grassland community (Buckland et al., 2001;Moser et al., 2011). Seed production of many species declines towards their northern range limit (Jump and Woodward, 2003), which may be the consequence of either physiological limitations on seed development (Pigott and Huntley, 1981) or a general reduction in plant growth. ...
Calcareous grasslands are considered as hotspots of plant and invertebrate diversity but little is known about the potential of their main dominants to migrate as a response to climate change. Although it is generally acknowledged that climate warming will allow plant species to expand their ranges northwards and upwards, not all restrictions on dispersal may be climate dependent. We assessed dispersal limitations in Bromopsis erecta and Brachypodium pinnatum, two dominant grasses of calcareous grasslands in Central Europe and southern England. Both species are known to spread rapidly in the absence of disturbance and are thus expected to have major impacts on species diversity and ecosystem functioning of northern calcareous grasslands. Pollination experiments showed that seed production in B. erecta, and we suspect also in B. pinnatum, at the northern range margin is climatically limited, which suggests that the species will be able to produce seeds outside their current distribution under climate warming. Self-incompatibility, on the other hand, is likely to considerably slow northward migration, as isolated founder populations may be unable to set seed, especially since calcareous grasslands are sparse and fragmented. Our results have important practical implications for managers attempting to slow the spread of these potential dominants, and also for those trying to encourage the northward migration of rare self-incompatible species in response to climate change.
... This finding may be attributed to the following underlying mechanisms. First, selection, dispersal and drift, as key ecological processes of plant community assembly, are closely correlated with environmental change (Moser et al., 2011;Tovar et al., 2020). In this study, the relative contributions of selection, dispersal and drift processes to plant community turnover along the elevation gradient under the warming conditions were different from those under the control conditions. ...
... The change in predominant/limited factor may result in the survival of species that are more adaptable to dominant/ limited factors and subsequently alter plant community assembly toward niche partitioning related to dominant factor (Klanderud and Birks, 2003;Zhang et al., 2020). Fourth, plant dispersal can play very important roles in plant species survival and community assembly (Moser et al., 2011). In this study, species β-diversity showed a closer correlation with geographic distance under warming conditions than control conditions along the elevation gradient, indicating that warming may increase the dispersal limitation of plant species along the elevation gradient (Kembel, 2009;Zimmer et al., 2018). ...
Warming is an important climate change, both plant diversity and aboveground net primary production (ANPP) are closely correlated with ecosystem functions and services. A field warming experiment along an elevation gradient (4313–4693 m) was performed in three alpine grassland sites, the Northern Tibet to investigate whether warming can alter elevation distribution patterns of ANPP, species and phylogenetic diversity. Warming altered elevational distributions of plant species and phylogenetic diversity by reducing α-diversity, but increased β-diversity among the three elevations. These warming effects on elevation distributions of plant diversity can be due to warming-induced changes in the relative contributions of selection, dispersal and drift, and the elevational distributions of soil and air temperatures, soil moisture, vapor pressure deficit, soil pH, soil available nitrogen and phosphorus. Warming altered the elevational distribution of ANPP by altering the elevation distributions of plant diversity and abiotic factors. Therefore, warming can alter the elevation distribution patterns of ANPP, species and phylogenetic diversity in alpine grasslands.
... Amongst 171 forest plant species of western Europe, species with faster life-cycles shifted to higher elevations with changing climate more rapidly than species with slower life-cycles (Lenoir et al. 2008). Species with traits favouring persistence in novel climates, may not necessarily have traits for wide dispersal, thereby limiting expansion (Moser et al. 2011). In this example, range stasis in species otherwise suited to climatic conditions outside of their current range could be mistakenly attributed to invasion resistance of the surrounding communities rather than to dispersal limitation. ...
... Th e trait approach often relies on correlations, and actual, but unobserved , traits conferring invasiveness might be correlated with other, ' neutral ' , traits that could be wrongly interpreted as important (van Kleunen et al. 2010). To predict species ' colonisation it is therefore critical that both invasion and climate change ecology experimentally measure population responses where possible to untangle the mechanisms driving responses (Moser et al. 2011). A challenge in applying the trait-based approach to forecasting climate change is caused by the interactions among climate, other sources of global change, traits, and population dynamics. ...
SynthesisPrediction and management of species responses to climate change is an urgent but relatively young research field. Therefore, climate change ecology must by necessity borrow from other fields. Invasion ecology is particularly well-suited to informing climate change ecology because both invasion ecology and climate change ecology address the trajectories of rapidly changing novel systems. Here we outline the broad range of active research questions in climate change ecology where research from invasion ecology can stimulate advances. We present ideas for how concepts, case-studies and methodology from invasion ecology can be adapted to improve prediction and management of species responses to climate change.A major challenge in this era of rapid climate change is to predict changes in species distributions and their impacts on ecosystems, and, if necessary, to recommend management strategies for maintenance of biodiversity or ecosystem services. Biological invasions, studied in most biomes of the world, can provide useful analogs for some of the ecological consequences of species distribution shifts in response to climate change. Invasions illustrate the adaptive and interactive responses that can occur when species are confronted with new environmental conditions. Invasion ecology complements climate change research and provides insights into the following questions: 1) how will species distributions respond to climate change? 2) how will species movement affect recipient ecosystems? And 3) should we, and if so how can we, manage species and ecosystems in the face of climate change? Invasion ecology demonstrates that a trait-based approach can help to predict spread speeds and impacts on ecosystems, and has the potential to predict climate change impacts on species ranges and recipient ecosystems. However, there is a need to analyse traits in the context of life-history and demography, the stage in the colonisation process (e.g. spread, establishment or impact), the distribution of suitable habitats in the landscape, and the novel abiotic and biotic conditions under which those traits are expressed. As is the case with climate change, invasion ecology is embedded within complex societal goals. Both disciplines converge on similar questions of ‘when to intervene?‘ and ‘what to do?‘ which call for a better understanding of the ecological processes and social values associated with changing ecosystems.
... However, the timing of seedling emergence was important. With warming alone, earlier emergence of seeds from the southern invaders Brachypodium pinnatum and Bromus erectus at the northern site resulted in increased biomass by the end of the growing season (Moser et al., 2011). Summer drought did not affect B. erectus but negated the benefits of warming for B. pinnatum. ...
Temperate (broadleaved) deciduous forests occur in eastern North America, western and central Europe, and eastern Asia. In these regions, temperatures are expected to increase by up to 5°C by 2100, and increases in precipitation may be offset by increased evaporation, leading to decreases in soil moisture. One likely response to climate change will be shifts in germination phenology that may have important repercussions in the population dynamics of species and community structure/composition. However, the regeneration response of species to climate change will be dependent on interactions with biotic, like herbivory, and nonclimatic abiotic factors, such as atmospheric nitrogen deposition. Geographic range shifts of a species will depend on seed production and dispersal, germination, seedling survival, soil conditions, and interactions with other species already present. Future research needs to focus on how germination and seedling survival will interact with other seed and species functional traits in response to the complexity of a changing climate, such as extreme climatic events.
... For example, dispersal capabilities and conditions for germination and establishment will determine if and where species move within climatically suitable areas. In some cases, dispersal limitations can impede invasions more than biotic resistance (Moser et al. 2011). Schweiger et al. (2008) found that the dispersal capabilities of interacting species are highly influential in determining their future distributions, with significant expansions in distribution with unlimited dispersal (goes everywhere that is predicted suitable), but significant decreases when dispersal is highly restricted (future range only includes overlap between present suitability and future suitability). ...
Establishment of new populations is contingent on overcoming abiotic and biotic barriers. While this applies to all species, these hurdles are at the forefront of invasion biology where prediction, prevention, eradication, and control strategies depend on an understanding of these processes. Terrestrial Arundina graminifolia and epiphytic Dendrobium crumenatum are two non-indigenous orchids spreading throughout Puerto Rico. The two species have acquired a native herbivore and seed predator, the orchid-specialist weevil, Stethobaris polita. With recently acquired presence records of the three species, land cover data and downscaled climate variables, we modeled their potential distributions under current conditions and also those projected under the least and most extreme climate scenarios for 2050 and 2070. We show that D. crumenatum flourishes in urban environments which also provide refugia from S. polita, whereas there is currently limited refugia for A. graminifolia from S. polita attack, as this orchid has similar climatic niches as the weevil. Projections into all climate scenarios suggest range retractions for all species, with a decreased extent of both orchid populations subject to S. polita attack. Thus, we illustrate for island invasions how climate change will likely alter the distribution of acquired biotic interactions.
... This could have been due to reduced germination rates under future climate conditions if temperatures exceeded the optimum conditions for germination (Lonati, Moot, Aceto, Cavallero & Lucas 2009). Drought events are known to negatively affect germination of B. erectus (Moser, Fridley, Askew & Grime 2011). Mowing might have benefitted fall and spring seedling recruitment through lower above-ground competition, as vegetation cover was lower in mown compared to grazed grassland communities (mean vegetation cover including dead and living biomass in August 2018: mowing 64% vs. grazing 82%; Auge et al., unpublished data). ...
Climate and land management are important environmental drivers that affect the structure of terrestrial plant communities worldwide. Demographic studies allow a mechanistic understanding of the pathways in which environmental factors change population size. Climate and land management might interactively influence vital rates and growth rates of populations, however, demographic studies have not heretofore considered both factors in combination. We used the Global Change Experimental Facility as a platform to study the effect of climate (ambient climate conditions vs. future climate conditions) and land management (sheep grazing vs. mowing) on the demography of the common grass, Bromus erectus growing in semi-natural grassland communities. Using an integral projection model, we found positive population growth rates for B. erectus under all treatment combinations, and an interactive effect of climate and land management. Under ambient climate conditions, population growth of B. erectus was higher in mowed than grazed grassland plots, while population growth rates were similar across both management types under future climatic conditions. This interaction was primarily due to between-treatment changes in seedling recruitment, a vital rate for which the population growth rate is particularly sensitive. The interaction found in this study highlights the importance of considering multiple environmental drivers in demographic studies, to better predict future plant population dynamics and ultimately changes in community structure.
... Projected range shifts will not necessarily occur because dispersal capabilities and conditions for germination and establishment will determine if and where species move within climatically suitable areas. In some cases, dispersal limitations can impede invasions more than biotic resistance (Moser et al. 2011). Schweiger et al. (2008) found that the dispersal capabilities of interacting species are highly in uential in determining their future distributions, with signi cant expansions in distribution with unlimited dispersal (goes everywhere that is predicted suitable), but signi cant decreases when dispersal is highly restricted (future range only includes overlap between present suitability and future suitability). ...
Establishment of new populations is contingent on overcoming abiotic and biotic barriers. While this applies to all species, these hurdles are at the forefront of invasion biology where prediction, prevention, eradication, and control strategies depend on an understanding of these processes. Arundina graminifolia and Dendrobium crumenatum are two non-indigenous orchids spreading throughout Puerto Rico. The two species have acquired a native herbivore & seed predator, the orchid-specialist weevil, Stethobaris polita . With recently acquired presence records of the three species, land cover data and BioClim variables, we modeled their potential distributions under current conditions and also those projected under the least and most extreme climate scenarios for 2050 and 2070. We show that D. crumenatum flourishes in urban environments which also provide refugia from S. polita, whereas there is currently limited refugia for A. graminifolia from S. polita attack, as this orchid is sensitive to the same climatic variables as the weevil. Projections into all climate scenarios suggest range retractions for all species, with an equal to or greater proportion of both orchid populations subject to S. polita attack. Thus, we illustrate for island invasions how climate change will likely alter the distribution of acquired biotic interactions.
... Our predictions are in terms of the maximum potential abundances of species, so that results interpretation pertains to potential changes in abundance. Realization of the predicted shift in distribution will depend on population dynamics including source-sink processes (Fordham et al. 2013), on the ability of species to cope with warming in situ by thermal tolerance (Bertrand et al. 2016) or phenological plasticity (Amano et al. 2014), on the dispersal and colonization capacity of species (Moser et al. 2011), on the impediments they will encounter to follow temperature shifts (Dullinger et al. 2015), and on the limiting effect of factors beyond temperature in future destinations. Wind-dispersed grasses and bryophytes (e.g. C. arundinacea and D. polysetum) are likely to respond more effectively to released climate limitations than short herbs with low seed production and very local dispersion (M. ...
Forecasting the impact of future global warming on biodiversity requires understanding how temperature limits the distribution of species. Here we rely on Liebig's Law of Minimum to estimate the effect of temperature on the maximum potential abundance that a species can attain at a certain location. We develop 95%‐quantile regressions to model the influence of effective temperature sum on the maximum potential abundance of 25 common understory plant species of Finland, along 868 nationwide plots sampled in 1985. Fifteen of these species showed a significant response to temperature sum that was consistent in temperature‐only models and in all‐predictors models, which also included cumulative precipitation, soil texture, soil fertility, tree species and stand maturity as predictors. For species with significant and consistent responses to temperature, we forecasted potential shifts in abundance for the period 2041–2070 under the IPCC A1B emission scenario using temperature‐only models. We predict major potential changes in abundance and average northward distribution shifts of 6–8 km yr−1. Our results emphasize inter‐specific differences in the impact of global warming on the understory layer of boreal forests. Species in all functional groups from dwarf shrubs, herbs and grasses to bryophytes and lichens showed significant responses to temperature, while temperature did not limit the abundance of 10 species. We discuss the interest of modelling the ‘maximum potential abundance’ to deal with the uncertainty in the predictions of realized abundances associated to the effect of environmental factors not accounted for and to dispersal limitations of species, among others. We believe this concept has a promising and unexplored potential to forecast the impact of specific drivers of global change under future scenarios.
... One reason for the high resistance of this infertile grassland may be the small-scale spatial heterogeneity in soil depth allowing the coexistence of drought-tolerant and more mesic species at small spatial scales (Fridley et al. 2011). As indicated by seed addition experiments, the minor changes in species composition, even after long-term climate treatments, are significantly affected by dispersal limitation rather than just biotic resistance (Moser et al. 2011). The prominent role of dispersal limitation as a cause of delayed response to climate effects has also been highlighted in several other studies (Buckland et al. 2001; Stampfli and Zeiter 2004; Zeiter et al. 2006). ...
The chapter starts with a discussion of general patterns and processes in terrestrial ecosystems, including the impacts of climate change in relation to productivity, phenology, trophic matches and mismatches, range shifts and biodiversity. Climate impacts on specific ecosystem types—forests, grasslands, heathlands, and mires and peatlands—are then discussed in detail. The chapter concludes by discussing links between changes in inland ecosystems and the wider North Sea system. Future climate change is likely to increase net primary productivity in the North Sea region due to warmer conditions and longer growing seasons, at least if summer precipitation does not decrease as strongly as projected in some of the more extreme climate scenarios. The effects of total carbon storage in terrestrial ecosystems are highly uncertain, due to the inherent complexity of the processes involved. For moderate climate change, land use effects are often more important drivers of total ecosystem carbon accumulation than climate change. Across a wide range of organism groups, range expansions to higher latitudes and altitudes and changes in phenology have occurred in response to recent climate change. For the range expansions, some studies suggest substantial differences between organism groups. Habitat specialists with restricted ranges have generally responded very little or even shown range contractions. Many of already threatened species could be particularly vulnerable to climate change. Overall, effects of recent climate change on terrestrial ecosystems within the North Sea region are still limited.
... These patterns, however, may not directly translate to variations of forest above ground biomass (AGB) as diameter and wood density of trees also control the forest AGB and influence the landscape heterogeneity [22,23]. Over sharp gradients such as tropical montane forests, tree height decreases with the rising elevation as proxy for decreasing temperature [24], present a combined effect of both climatic factors and edaphic properties. Studies using field observations also show that the aboveground live biomass variations at landscape scales, which are highly related to the variation of large trees [25], are positively correlated with soil texture gradients and topography. ...
Spatial variation of tropical forest tree height is a key indicator of ecological processes associated with forest growth and carbon dynamics. Here we examine the macroscale variations of tree height of humid tropical forests across three continents and quantify the climate and edaphic controls on these variations. Forest tree heights are systematically sampled across global humid tropical forests with more than 2.5 million measurements from Geoscience Laser Altimeter System (GLAS) satellite observations (2004-2008). We used top canopy height (TCH) of GLAS footprints to grid the statistical mean and variance and the 90 percentile height of samples at 0.5 degrees to capture the regional variability of average and large trees globally. We used the spatial regression method (spatial eigenvector mapping-SEVM) to evaluate the contributions of climate, soil and topography in explaining and predicting the regional variations of forest height. Statistical models suggest that climate, soil, topography, and spatial contextual information together can explain more than 60% of the observed forest height variation, while climate and soil jointly explain 30% of the height variations. Soil basics, including physical compositions such as clay and sand contents, chemical properties such as PH values and cation-exchange capacity, as well as biological variables such as the depth of organic matter, all present independent but statistically significant relationships to forest height across three continents. We found significant relations between the precipitation and tree height with shorter trees on the average in areas of higher annual water stress, and large trees occurring in areas with low stress and higher annual precipitation but with significant differences across the continents. Our results confirm other landscape and regional studies by showing that soil fertility, topography and climate may jointly control a significant variation of forest height and influencing patterns of aboveground biomass stocks and dynamics. Other factors such as biotic and disturbance regimes, not included in this study, may have less influence on regional variations but strongly mediate landscape and small-scale forest structure and dynamics.
... The functional process of riparian litter decomposition in freshwater streams will likely be affected in future decades because of global change (Ferreira et al. 2010;Song et al. 2011;Jenkins et al. 2013). Various events will occur in this context, such as changes in riparian vegetation communities (Cheaib et al. 2012;Rigling et al. 2013), the arrival of exotic species (Graça et al. 2002;Moser et al. 2011), increases in temperature and changes in precipitation regime (Beniston et al. 2007;Rigling et al. 2013). In parallel, climate change will also entail modifications of both microorganism (Fernandes et al. 2009;Ferreira & Chauvet 2012) and in-vertebrate (Ferreira et al. 2010;Leberfinger et al. 2010) communities, which will affect the litter decomposition process. ...
Climate change will likely affect riparian litter decomposition in freshwater streams in future decades by modifications in both microorganism and invertebrate activities. On the one hand, the expected increase in C:N ratio will decrease the palatability of leaf litter, and consequently slow down decomposition rates of leaves. On the other hand, rising temperatures may stimulate litter decomposition.We conducted a feeding study that associated the key shredder species Gammarus pulex (Crustacea, Amphi- poda) with common riparian leaf litter (from the tree Alnus glutinosa) from European freshwater streams. We assessed the effects of temperature on i) changes in leaf palatability during conditioning (microbial colonisation), ii) leaf consumption rates, and iii) leaf digestion by shredders. Moreover, we compared the responses to rising temperatures between two populations of G. pulex, living in contrasting thermal environments (humid continental climate vs. temperate Mediterranean climate).We found that the decreased mechanical resistance of leaf tissue, which was induced by the conditioning, was stimulated by an increase in temperature. However, we found no increase in fungal biomass even at the highest temperatures (21 and 24 °C). The leaf consumption rate by amphipods increased slightly but not linearly with ris- ing temperatures. Moreover, digestive enzyme activities in amphipod guts were clearly favoured by an increase in water temperature. Catalytic activities of digestive enzymes were generally higher for amphipods living under continental climate conditions.Our study supported the idea that the effect of rising temperatures on the leaf litter decomposition would not be unidirectional. Higher temperatures would lead to contrasting impacts on both physiology and ecology of organ- isms involved in this functional process.
... The functional process of riparian litter decomposition in freshwater streams will likely be affected in future decades because of global change (Ferreira et al. 2010;Song et al. 2011;Jenkins et al. 2013). Various events will occur in this context, such as changes in riparian vegetation communities (Cheaib et al. 2012;Rigling et al. 2013), the arrival of exotic species (Graça et al. 2002;Moser et al. 2011), increases in temperature and changes in precipitation regime (Beniston et al. 2007;Rigling et al. 2013). In parallel, climate change will also entail modifications of both microorganism (Fernandes et al. 2009;Ferreira & Chauvet 2012) and in-vertebrate (Ferreira et al. 2010;Leberfinger et al. 2010) communities, which will affect the litter decomposition process. ...
Climate change will likely affect riparian litter decomposition in freshwater streams in future decades by modifications in both microorganism and invertebrate activities. On the one hand, the expected increase in C:N ratio will decrease the palatability of leaf litter, and consequently slow down decomposition rates of leaves. On the other hand, rising temperatures may stimulate litter decomposition. We conducted a feeding study that associated the key shredder species Gammarus pulex (Crustacea, Amphipoda) with common riparian leaf litter (from the tree Alnus glutinosa) from European freshwater streams. We assessed the effects of temperature on i) changes in leaf palatability during conditioning (microbial colonisation), ii) leaf consumption rates, and iii) leaf digestion by shredders. Moreover, we compared the responses to rising temperatures between two populations of G. pulex, living in contrasting thermal environments (humid continental climate vs. temperate Mediterranean climate). We found that the decreased mechanical resistance of leaf tissue, which was induced by the conditioning, was stimulated by an increase in temperature. However, we found no increase in fungal biomass even at the highest temperatures (21 and 24 degrees C). The leaf consumption rate by amphipods increased slightly but not linearly with rising temperatures. Moreover, digestive enzyme activities in amphipod guts were clearly favoured by an increase in water temperature. Catalytic activities of digestive enzymes were generally higher for amphipods living under continental climate conditions. Our study supported the idea that the effect of rising temperatures on the leaf litter decomposition would not be unidirectional. Higher temperatures would lead to contrasting impacts on both physiology and ecology of organisms involved in this functional process.
... The results of this research suggest that even without these two mechanisms, forecasting the future of ecosystems and the services they provide will require knowledge, currently lacking, on the migration rates (and barriers to migration) of key species. If today's populations of dominant plant species cannot keep pace with climate change, then greater understanding of genetic and phenotypic variation throughout a species range, and the rates of adaptation for these dominant species must be investigated, particularly under conditions where there are realistic interspecific interactions (Eckert et al. 2008;Hoffmann and Blows 1994;Lesica and Allendorf 1995;Moser et al. 2011). ...
Aims The rate of climate change may exceed many plant species’ migration rates, particularly for long-lived perennial species
that dominate most ecosystems. If bioclimatic envelopes shift more rapidly than dominant species can migrate, individuals
located peripheral to biomes or in adjacent biomes may become a significant source of traits for future dominant populations
(DPs). Thus, traits of individuals from peripheral populations (PPs) may affect future ecosystem functioning more than those
of today’s DPs.
... We chose Bromus erectus and Brachypodium pinnatum as target species to measure biotic interactions for two reasons. First, both grass species are very frequent in poorly managed and nutrient-poor calcareous grasslands throughout Europe (Willems 1980;Royer 1987) and have been widely used in a number of experiments (Bobbink 1991;Corcket et al. 2003;Liancourt, Callaway & Michalet 2005;Moser et al. 2011). Secondly, although they are both considered stress-tolerant competitors (C-S) by Grime, Hodgson & Hunt (1988), a number of authors have shown strong functional differences among them, B. erectus being more tolerant to both drought stress and disturbance and B. pinnatum being more competitive (Corcket et al. 2003) and dominant in abandoned mesic grasslands (Hurst & John 1999). ...
1. Climate change is rarely taken into consideration in conservation management strategies aimed at protecting biodiversity from other threats. We examined the implications of this perspective in European calcareous grasslands, which are among the richest herbaceous systems of the continent and are therefore of high nature conservation interest. These systems are currently undergoing species loss because of the abandonment of agro-pastoral practices. Classic ecological theory assumes that conservation management activities (such as regular mowing) and drought events should increase diversity through decreased plant competition in abandoned mesic communities. In turn, this could reduce diversity in xeric communities although positive plant interactions (facilitation) might buffer these negative effects and maintain diversity.
... For widely distributed species, characterising changes at the intra-specific level could be crucial to highlight the potential effects of climate changes. Climate changes are also associated with changes in the distribution of vegetation species [19], [20], [21], which might significantly modify the availability of feeding resources in terrestrial and adjacent aquatic ecosystems, because the consumption of the leaves of riparian trees by the shredder species constitutes a major allochtonous trophic resource for temperate stream ecosystems [22], [23]. In addition, the shredder leaf consumption rate is influenced by leaf characteristics [24], [25]. ...
As a consequence of global warming, it is important to characterise the potential changes occurring for some functional processes through the intra-specific study of key species. Changes in species distribution, particularly when key or engineer species are affected, should contribute to global changes in ecosystem functioning. In this study, we examined the potential consequences induced by global warming on ecosystem functioning in term of organic matter recycling. We compared consumption of leaf litter by some shredder populations (Gammarus pulex) between five tree species inhabiting continental (i.e., the northern region of the Rhône River Valley) and/or Mediterranean (i.e., the southern region of the Rhône River Valley) conditions. To consider any potential adaptation of the gammarid population to vegetation in the same climate conditions, three populations of the key shredder Gammarus pulex from the northern region and three from the southern region of the Rhône River Valley were used. We experimentally compared the effects of the geographical origin of both the gammarid populations and the leaf litter species on the shredding activity and the physiological state of animals (through body triglyceride content). This study demonstrated that leaf toughness is more important than geographical origin for determining shredder leaf litter consumption. The overall consumption rate of the gammarid populations from the southern region of Rhône Valley was much higher than that of the populations from the northern region, but no clear differences between the origins of the leaf litter (i.e., continental vs. Mediterranean) were observed. The northwards shift of G. pulex populations adapted to warmer conditions might significantly modify organic matter recycling in continental streams. As gammarid populations can demonstrate local adaptations to certain leaf species as a trophic resource, changes in riparian vegetation associated with climate change might locally affect the leaf litter degradation process by this shredder.
... 2008; Moser et al. 2011; Thaxton et al. 2011). The presence of disturbance allowed P. setaceum to compete with Heteropogon contortus, a native grass, but, H. contortus tolerated drought better than P. setaceum , suggesting that a native grass may outcompete the invasive grass in dry habitats ( Daehler 2001, 2002). ...
The restoration of native plant diversity may be an effective tool for weed control, but its use has not been tested in the heavily invaded Hawaiian dry forest ecosystem. In addition, the ecological mechanisms by which invasive plants may cause declines in native plant diversity are generally not well understood. We examined invasion resistance and the relationships between invasion and declines in native plant diversity at local scales in a Hawaiian dry forest restoration by experimentally removing non-native species, planting native species, manipulating resources and environmental conditions, and allowing non-native species to re-invade. We found higher invasion rates in habitats that supported the most native species, suggesting that similar mechanisms may regulate the distribution of both native and invasive species. Pennisetum setaceum, a dominant invasive perennial grass, was associated with native plant mortality and declines in native diversity. Although invasion rates were greatest in more favorable habitats, the association of invasion with native species loss was significant only in lower quality habitats, suggesting that environmental conditions may regulate competitive interactions between native and invasive species. We found that native woody plant restoration is not an effective tool for weed control in this community, and that invasion may result in declines in native diversity. Our study provides a caveat to previous suggestions that invasion impacts on native diversity will be greatest in the most diverse plant communities. At local scales in some communities it may also be effective to control invasive species in sensitive areas with low resource availability instead of, or in addition to, areas with high biodiversity.
... Kullman, 2001; Grace et al., 2002;Moen et al., 2004). Besides, successful poleward shifts of plant species ranges will depend on interactions between migrating species and the communities they invade (Moser et al., 2011). In Arctic terrestrial ecosystems, geographical barriers such as the distribution of landmasses and separation by seas, will affect the northwards shift in vegetation zones (Callaghan et al., 2004). ...
Abstract. Global average temperature has increased and precipitation pattern has altered over the past
100 years due to increases in greenhouse gases. These changes will alter numerous site factors and
biochemical processes of vegetative communities such as nutrient and water availability, permafrost
thawing, fire regime, biotic interactions and invasion. As a consequence, climate change is expected to
alter distribution ranges of many species and communities as well as boundaries of biomes. Shifting of
species and vegetation zones northwards and upwards in elevation has already been observed. Besides,
several experiments have been conducted and simulations have been run all over the world in order to
predict possible range shifts and ecological risks. In this paper, we review literature available in Web of
Science on Europe and boreal Eurasia and give an overview of observed and predicted changes in
vegetation in these regions. The main trends include advance of the tree line, reduction of the alpine
vegetation belt, drought risk, forest diebacks, a shift from coniferous forests to deciduous forests and
invasion. It is still controversial if species migration will be able to keep pace with climate change.
Keywords: global warming, vegetation distribution, biome, vegetation zone, plant community
... We chose Bromus erectus and Brachypodium pinnatum as target species to measure biotic interactions for two reasons. First, both grass species are very frequent in poorly managed and nutrient-poor calcareous grasslands throughout Europe (Willems 1980;Royer 1987) and have been widely used in a number of experiments (Bobbink 1991;Corcket et al. 2003;Liancourt, Callaway & Michalet 2005;Moser et al. 2011). Secondly, although they are both considered stress-tolerant competitors (C-S) by Grime, Hodgson & Hunt (1988), a number of authors have shown strong functional differences among them, B. erectus being more tolerant to both drought stress and disturbance and B. pinnatum being more competitive (Corcket et al. 2003) and dominant in abandoned mesic grasslands (Hurst & John 1999). ...
There is still debate regarding the direction and strength of plant interactions under intermediate to high levels of stress. Furthermore, little is known on how disturbance may interact with physical stress in unproductive environments, although recent theory and models have shown that this interplay may induce a collapse of plant interactions and diversity. The few studies assessing such questions have considered the intensity of biotic interactions but not their importance, although this latter concept has been shown to be very useful for understanding the role of interactions in plant communities. The objective of this study was to assess the interplay between stress and disturbance for plant interactions in dry calcareous grasslands.
A field experiment was set up in the Dordogne, southern France, where the importance and intensity of biotic interactions undergone by four species were measured along a water stress gradient, and with and without mowing disturbance.
The importance and intensity of interactions varied in a very similar way along treatments. Under undisturbed conditions, plant interactions switched from competition to neutral with increasing water stress for three of the four species, whereas the fourth species was not subject to any significant biotic interaction along the gradient. Responses to disturbance were more species-specific; for two species, competition disappeared with mowing in the wettest conditions, whereas for the two other species, competition switched to facilitation with mowing. Finally, there were no significant interactions for any species in the disturbed and driest conditions.
At very high levels of stress, plant performances become too weak to allow either competition or facilitation and disturbance may accelerate the collapse of interactions in dry conditions. The results suggest that the importance and direction of interactions are more likely to be positively related in stressful environments.
... Forecasts of rapid migration rates are common to niche-based approaches (e.g. Iverson & Prasad 1998), and strict niche-based forecasts likely need tempering because dispersal limitation will limit migration rates (Morin, Viner & Chuine 2008; Cole 2010; Moser et al. 2011). MaxEnt can potentially account for dispersal limitation by using more informative prior distributions that reflect local abundance patterns (Sonnier, Shipley & Navas 2010). ...
1. Climatic constraints on plant distributions are well known, but predicting community composition through knowledge of trait-based environmental filtering remains an important empirical challenge. Here, we evaluate the maximum entropy (MaxEnt) model of trait-based community assembly using forest communities occurring along a 12 °C gradient of mean annual temperature (MAT).We use independent cross-validation to evaluate model predictions from sites where trait constraints are predicted from environmental conditions. We also test whether orthogonal axes of trait variation can be used as predictors to improve model parsimony and explore MaxEnt forecasts of species distributions in a warmer climate.
John Philip ‘Phil’ Grime developed fundamental theory in plant ecology that emerged from a lifetime of fieldwork and experimental studies in the Sheffield region, South Yorkshire, UK. His approach was an unusual combination of observation, experiment and theory: he conducted detailed, intensive observations of natural communities, alongside experimental manipulation of those communities and simulated ‘microcosms’ in the service of formulating general rules (‘strategies’) by which plants evolve with respect to their environment. In this way, Grime was one of several key figures that propelled plant ecology away from descriptive methods focusing on vegetation composition and toward a science more integrated with other fields, including evolutionary biology and Earth science. Grime's investigative approach was an inspiration for the modern field of global change biology, and, by focusing on understanding the contrasting roles species and their traits play in the functioning of ecosystems, marked the beginning of the field of plant functional ecology. For much of his career Grime held the post of full professor (and in retirement, emeritus professor of ecology) at the University of Sheffield, where he also served as the director of the Unit of Comparative Plant Ecology and of the Buxton Climate Change Impacts Laboratory. Awarded an honorary doctorate by Radboud University (Nijmegen, The Netherlands) and a foreign membership of the Royal Netherlands Academy of Arts and Sciences, Grime was the first person awarded the Alexander von Humboldt Award of the International Association for Vegetation Science.
Significance
Understanding how and why communities vary in their responses to climatic change is critical for global biodiversity conservation. In a 5-y experimental study of a heterogeneous grassland system, we found that the most nutrient-limited communities were relatively insensitive to alterations in rainfall, but that this insensitivity could be reversed by nutrient addition, leading to greatly enhanced productivity, near-complete species turnover, and accelerated diversity loss. Species with slow-growing, resource-conserving traits were especially vulnerable to decline. These results highlight that the ecological principle of colimitation by water and nutrients can lead to powerful predictions about climate change impacts on natural communities.
This chapter assesses recent literature on the opportunities that create enabling conditions for adaptation as well as the ancillary benefits that may arise from adaptive responses. It also assesses the literature on biophysical and socioeconomic constraints on adaptation and the potential for such constraints to pose limits to adaptation. Given the available evidence of observed and anticipated limits to adaptation, the chapter also discusses the ethical implications of adaptation limits and the literature on system transformational adaptation as a response to adaptation limits.
Background/Question/Methods
Despite concerns that invasive plant species may cause declines in native plant diversity, the ecological mechanisms potentially causing these declines are poorly understood. Invasive species may reduce native diversity by reducing colonization rates or accelerating extinction rates. We examined the relationships between invasion and declines in native plant diversity at local scales in a Hawaiian dry forest by experimentally removing non-native species, planting native species, and manipulating resources and environmental conditions.
Results/Conclusions
We found higher invasion rates in habitats that supported the most native species, suggesting that underlying resource availability drives the distribution of both native and invasive species. Pennisetum setaceum, a dominant invasive perennial grass, was associated with accelerated local native extinction rates and declines in native diversity. Although invasion rates were greatest in more favorable habitats, the impact of invasion on native species loss was significant only in habitats with lower resource supply.
We found evidence supporting an “extinction debt” due to current levels of plant invasions, highlighting the importance of management programs for threatened and endangered plant species. Our study provides an important caveat to previous suggestions that invasion impacts on native diversity will be greatest in the most diverse plant communities. In some ecosystems it may be more effective to control invasive species in sensitive areas with low resource availability instead of in hotspots of biodiversity.
Populations of the common perennial herb Plantago lanceolata L. have been exposed to nearly two decades of summer drought at the Buxton Climate Change Experiment (BCCIL), a controlled manipulation of climate factors in a species-rich limestone grassland in northern England.We used a common garden approach to test for evidence of selection for different suites of functional traits in P. lanceolata populations exposed to chronic summer drought and across a soil depth gradient.The main axis of functional variation reflected a trade-off between reproductive and vegetative allocation, consistent with drought avoidance and competitive strategies, respectively. Avoidance strategies were more prominent in droughted populations, whereas competitive strategies were more prominent in populations from control treatments. Treatment differences were more pronounced in shallower soils. Deeper soils in both control and drought treatments promoted functional differentiation associated with competitive strategies, suggesting that selective pressures imposed by different climate treatments are modified by fine-scale edaphic heterogeneity.Synthesis. Results suggest that population-level shifts can be a mechanism of resistance to local climate-induced extinction. Trait differentiation with respect to fine-scale variation in soil depth suggests that edaphic heterogeneity fosters high local genetic diversity, which provides a range of local phenotypes upon which drought-based selection may act.
In order to assess the influence of experimental warming on individual species response, species composition and richness, and the abundance of ramets in a wet late-melting snowbed, we established 20 open-top chambers (OTCs) permanently for 5 yr (six growing seasons) at Finse, southwest Norway. Salix herbacea, Saxifraga stellaris, Omalotheca supina, Cerastium cerastoides, and Epilobium anagallidifolium increased in the experimentally warmed plots while there was no significant response in Carex lachenalii, Deschampsia alpina, Poa alpina, Juncus biglumis, Saxifraga rivularis, or Veronica alpina. Species composition changed significantly with time both in the OTCs and in the control plots. Although invasion rates slightly increased in the OTCs compared to the controls, differences in overall species composition or richness were not significant between the OTCs and the control plots during the 5-yr study. Our results suggest that vegetation change is going on naturally and that the effect of this change overrides the effect of the temperature treatment. We conclude that increased plant growth will result in denser vegetation in a warmer future. Whether the higher net invasion will result in more diverse vegetation is yet unclear, as the processes take more time than allowed for in this study.
Evolutionary community ecology is an emerging field of study that includes evolutionary principles such as individual trait variation and plasticity of traits to provide a more mechanistic insight as to how species diversity is maintained and community processes are shaped across time and space. In this review we explore phenotypic plasticity in functional traits and its consequences at the community level. We argue that resource requirement and resource uptake are plastic traits that can alter fundamental and realised niches of species in the community if environmental conditions change. We conceptually add to niche models by including phenotypic plasticity in traits involved in resource allocation under stress. Two qualitative predictions that we derive are: (1) plasticity in resource requirement induced by availability of resources enlarges the fundamental niche of species and causes a reduction of vacant niches for other species and (2) plasticity in the proportional resource uptake results in expansion of the realized niche, causing a reduction in the possibility for coexistence with other species. We illustrate these predictions with data on the competitive impact of invasive species. Furthermore, we review the quickly increasing number of empirical studies on evolutionary community ecology and demonstrate the impact of phenotypic plasticity on community composition. Among others, we give examples that show that differences in the level of phenotypic plasticity can disrupt species interactions when environmental conditions change, due to effects on realized niches. Finally, we indicate several promising directions for future phenotypic plasticity research in a community context. We need an integrative, trait-based approach that has its roots in community and evolutionary ecology in order to face fast changing environmental conditions such as global warming and urbanization that pose ecological as well as evolutionary challenges.
This paper explores the differences in the trait compositions of non-indigenous (neophytic) and native plant species for selected traits in Germany. Our set of functional traits addresses species’ reproductive biology, life history, morphology and ecophysiology. To take account of broad-scale heterogeneity across the country we compared the relative frequencies of neophytes and natives with particular trait attributes at the scale of grid cells (c. 130 km2 each). Subsequently, we compared the differences at the grid cell scale to the differences in the corresponding comparisons at the scale of the entire country. Finally, we explored how variation in the trait compositions of the non-indigenous species across the country relates to variation in the trait compositions of the natives. We found remarkable differences in the trait compositions of neophytes and natives at the grid cell scale. Neophytes were over-represented in insect- and self-pollinated species and in species with a later and longer flowering season. Furthermore, the proportions of species with mesomorphic or hygromorphic leaf anatomy, of annual herbs and of trees as well as of non-clonals and polyploids were significantly higher in neophytes than in natives. These differences at the grid cell scale could vary distinctly from the corresponding differences observed at the country scale. This result highlights the complexity of the invasion process and suggests an importance of spatial scale for the comparisons. Correlation analysis indicated, that for traits relating to plant morphology and ecophysiology, the relative frequencies of the non-indigenous species increased with those of the natives. This suggests that favourable environments for natives with particular attributes constitute an increased suitability for neophytes with these attributes as well. Our study provides a step forward towards an integrated understanding of traits in plant invasions across spatial scales and broad-scale heterogeneity and underlines the necessity to understand the role of functional traits in plant invasions with reference to spatial scale and in the context of the environment.
There is ample evidence for ecological responses to recent climate change. Most studies to date have concentrated on the effects of climate change on individuals and species, with particular emphasis on the effects on phenology and physiology of organisms as well as changes in the distribution and range shifts of species. However, responses by individual species to climate change are not isolated; they are connected through interactions with others at the same or adjacent trophic levels. Also from this more complex perspective, recent case studies have emphasized evidence on the effects of climate change on biotic interactions and ecosystem services. This review highlights the 'knowns' but also 'unknowns' resulting from recent climate impact studies and reveals limitations of (linear) extrapolations from recent climate-induced responses of species to expected trends and magnitudes of future climate change. Hence, there is need not only to continue to focus on the impacts of climate change on the actors in ecological networks but also and more intensively to focus on the linkages between them, and to acknowledge that biotic interactions and feedback processes lead to highly complex, nonlinear and sometimes abrupt responses.
Climate change due to greenhouse gas emissions is predicted to raise the mean global temperature by 1.0–3.5°C in the next 50–100 years. The direct and indirect effects of this potential increase in temperature on terrestrial ecosystems and ecosystem processes are likely to be complex and highly varied in time and space. The Global Change and Terrestrial Ecosystems core project of the International Geosphere-Biosphere Programme has recently launched a Network of Ecosystem Warming Studies, the goals of which are to integrate and foster research on ecosystem-level effects of rising temperature. In this paper, we use meta-analysis to synthesize data on the response of soil respiration, net N mineralization, and aboveground plant productivity to experimental ecosystem warming at 32 research sites representing four broadly defined biomes, including high (latitude or altitude) tundra, low tundra, grassland, and forest. Warming methods included electrical heat-resistance ground cables, greenhouses, vented and unvented field chambers, overhead infrared lamps, and passive night-time warming. Although results from individual sites showed considerable variation in response to warming, results from the meta-analysis showed that, across all sites and years, 2–9 years of experimental warming in the range 0.3–6.0°C significantly increased soil respiration rates by 20% (with a 95% confidence interval of 18–22%), net N mineralization rates by 46% (with a 95% confidence interval of 30–64%), and plant productivity by 19% (with a 95% confidence interval of 15–23%). The response of soil respiration to warming was generally larger in forested ecosystems compared to low tundra and grassland ecosystems, and the response of plant productivity was generally larger in low tundra ecosystems than in forest and grassland ecosystems. With the exception of aboveground plant productivity, which showed a greater positive response to warming in colder ecosystems, the magnitude of the response of these three processes to experimental warming was not generally significantly related to the geographic, climatic, or environmental variables evaluated in this analysis. This underscores the need to understand the relative importance of specific factors (such as temperature, moisture, site quality, vegetation type, successional status, land-use history, etc.) at different spatial and temporal scales, and suggests that we should be cautious in "scaling up" responses from the plot and site level to the landscape and biome level. Overall, ecosystem-warming experiments are shown to provide valuable insights on the response of terrestrial ecosystems to elevated temperature.
1 The invasion of habitats by non-native plant and animal species is a global phenomenon with potentially grave consequences for ecological, economic, and social systems. Unfortunately, to date, the study of invasions has been primarily anecdotal and resistant to generalization.
2 Here, we use insights from experiments and from long-term monitoring studies of vegetation to propose a new theory in which fluctuation in resource availability is identified as the key factor controlling invasibility, the susceptibility of an environment to invasion by non-resident species. The theory is mechanistic and quantitative in nature leading to a variety of testable predictions.
3 We conclude that the elusive nature of the invasion process arises from the fact that it depends upon conditions of resource enrichment or release that have a variety of causes but which occur only intermittently and, to result in invasion, must coincide with availability of invading propagules.
Current predictions on species responses to climate change strongly rely on projecting altered environmental conditions on species distributions. However, it is increasingly acknowledged that climate change also influences species interactions. We review and synthesize literature information on biotic interactions and use it to argue that the abundance of species and the direction of selection during climate change vary depending on how their trophic interactions become disrupted. Plant abundance can be controlled by aboveground and belowground multitrophic level interactions with herbivores, pathogens, symbionts and their enemies. We discuss how these interactions may alter during climate change and the resulting species range shifts. We suggest conceptual analogies between species responses to climate warming and exotic species introduced in new ranges. There are also important differences: the herbivores, pathogens and mutualistic symbionts of range-expanding species and their enemies may co-migrate, and the continuous gene flow under climate warming can make adaptation in the expansion zone of range expanders different from that of cross-continental exotic species. We conclude that under climate change, results of altered species interactions may vary, ranging from species becoming rare to disproportionately abundant. Taking these possibilities into account will provide a new perspective on predicting species distribution under climate change.
Growing recognition of the importance of long-distance dispersal (LDD) of plant seeds for various ecological and evolutionary processes has led to an upsurge of research into the mechanisms underlying LDD. We summarize these findings by formulating six generalizations stating that LDD is generally more common in open terrestrial landscapes, and is typically driven by large and migratory animals, extreme meteorological phenomena, ocean currents and human transportation, each transporting a variety of seed morphologies. LDD is often associated with unusual behavior of the standard vector inferred from plant dispersal morphology, or mediated by nonstandard vectors. To advance our understanding of LDD, we advocate a vector-based research approach that identifies the significant LDD vectors and quantifies how environmental conditions modify their actions.
Instrumental observations and reconstructions of global and hemispheric temperature evolution reveal a pronounced warming during the past approximately 150 years. One expression of this warming is the observed increase in the occurrence of heatwaves. Conceptually this increase is understood as a shift of the statistical distribution towards warmer temperatures, while changes in the width of the distribution are often considered small. Here we show that this framework fails to explain the record-breaking central European summer temperatures in 2003, although it is consistent with observations from previous years. We find that an event like that of summer 2003 is statistically extremely unlikely, even when the observed warming is taken into account. We propose that a regime with an increased variability of temperatures (in addition to increases in mean temperature) may be able to account for summer 2003. To test this proposal, we simulate possible future European climate with a regional climate model in a scenario with increased atmospheric greenhouse-gas concentrations, and find that temperature variability increases by up to 100%, with maximum changes in central and eastern Europe.
Ecologists often consider how environmental factors limit a species' geographic range. However, recent models suggest that geographic distribution also may be determined by a species' ability to adapt to novel environmental conditions. In this study, we empirically tested whether further evolution would be necessary for northern expansion of the weedy annual cocklebur (Xanthium strumarium) in its native North American range. We transplanted seedlings beyond the northern border and photoperiodically manipulated reproductive timing, a trait important for adaptation to shorter growing seasons at higher latitudes within the range, to determine whether further evolution of this trait would result in a phenotype viable beyond the range. Earlier reproductive induction enabled plants to produce mature seeds beyond the range and to achieve a reproductive output similar to those grown within the range. Therefore, evolution of earlier reproduction in marginal populations would be necessary for northward range expansion. This study is the first to empirically show that evolution in an ecologically important trait would enable a species to survive and reproduce beyond its current range. These results suggest that relatively few traits may limit a species' range and that identifying evolutionary constraints on such traits could be important for predicting geographic distribution.
In experimentally heated plots that each span a soil moisture gradient in a Rocky Mountain meadow, aboveground biomass of
Artemisia tridentata (a sagebrush) increased in the drier habitat and that of Pentaphylloides floribunda (a shrub cinquefoil) increased in the wetter habitat relative to control plots. In contrast, aboveground forb biomass decreased
in the wet and dry habitats of the heated plots. These results, combined with evidence for enhanced sagebrush seedling establishment
rates in the heated plots, suggest that the increased warming expected under an atmosphere with a concentration of carbon
dioxide twice that of pre-industrial levels could change the dominant vegetation of a widespread meadow habitat.
Climate shifts over this century are widely expected to alter the structure and functioning of temperate plant communities. However, long-term climate experiments in natural vegetation are rare and largely confined to systems with the capacity for rapid compositional change. In unproductive, grazed grassland at Buxton in northern England (U.K.), one of the longest running experimental manipulations of temperature and rainfall reveals vegetation highly resistant to climate shifts maintained over 13 yr. Here we document this resistance in the form of: (i) constancy in the relative abundance of growth forms and maintained dominance by long-lived, slow-growing grasses, sedges, and small forbs; (ii) immediate but minor shifts in the abundance of several species that have remained stable over the course of the experiment; (iii) no change in productivity in response to climate treatments with the exception of reduction from chronic summer drought; and (iv) only minor species losses in response to drought and winter heating. Overall, compositional changes induced by 13-yr exposure to climate regime change were less than short-term fluctuations in species abundances driven by interannual climate fluctuations. The lack of progressive compositional change, coupled with the long-term historical persistence of unproductive grasslands in northern England, suggests the community at Buxton possesses a stabilizing capacity that leads to long-term persistence of dominant species. Unproductive ecosystems provide a refuge for many threatened plants and animals and perform a diversity of ecosystem services. Our results support the view that changing land use and overexploitation rather than climate change per se constitute the primary threats to these fragile ecosystems.
• calcareous grassland
• climate manipulation
• global change
• multivariate analysis
• vegetation
We test the hypothesis that the responses of vegetation to extreme events is a function of the nutrient stress tolerance of species present. The nutrient stress tolerance of a range of species was defined by a formalized procedure in which traits measured by screening in the laboratory were synthesized using principle components analysis. 2. Results were then compared with the results from a large-scale field experiment which examined the responses of five herbaceous plant communities in Derbyshire, UK to three extreme events (frost, drought and fire). 3. Nutrient stress tolerance was positively correlated with resistance to initial damage and negatively correlated with resilience (speed of recovery). The results illustrate the use of laboratory data to predict the field responses of plants to extreme events and demonstrate that the axis from high to low nutrient stress tolerance can play an effective role in predicting these responses.
This paper presents a perspective of how phylogenetic and phylogeographic hypotheses, based on nuclear DNA sequence variation (ITS) or amplified fragment length polymorphisms (AFLPs), can provide insights into the origin and evolution of the European high mountain flora. We focus on a diversity of unrelated herbaceous plant taxa that are broadly co-distributed across the European Alpine System, representing different taxonomic levels, and having either Mediterranean or Asian affinities (i.e., Anthyllis montana, Pritzelago alpina, Globularia vs. Soldanella, and Primula sect. Auricula). Our observations highlight that all taxa investigated began to diversify at the beginning of the Pleistocene or well within this period. Some of those taxa apparently followed different routes and modes of immigration, thereby colonizing the European high mountains only once (either from the East or the West) or repeatedly (from the Mediterranean Basin). Our observations further suggest that several high mountain taxa originated from lowland forms. While supporting earlier views, such a trend has generally been associated with pre-Quaternary rather than Pleistocene events. While several concordant patterns of (large-scale) spatial genetic differentiation are identified across taxa, such similarities may have arisen at either clearly different or roughly similar times. Finally, most speciation events likely occurred in allopatry, though more comprehensive studies are required to evaluate the relative importance of non-allopatric modes of speciation in the study area. We conclude that one major challenge to future evolutionary studies in European mountain plants is the accurate and reliable reconstruction of the tempo and mode of speciation across Quaternary time scales.
Invasion by exotic annual grasses is one of the most significant threats to arid ecosystems in the western USA. Current theories of invasibility predict plant communities become more susceptible to invasion whenever there is an increase in the amount of unused resources. The objective of this field study was to examine how resource pulses and temporal variation in resource demand by the native shrub vegetation influences establishment of the invasive annual grass Schismus arabicus. Water and nitrogen were applied as pulses in early spring, mid-spring, or continuously throughout the growing season to plots containing either Atriplex confertifolia or Atriplex parryi shrubs. The effect of resource pulses on Schismus density and biomass was highly dependent on the seasonal timing of the resource pulses and the identity of the neighbor shrub. When resource pulses coincided with high rates of resource capture and growth of the native vegetation, density and biomass of Schismus was reduced. Schismus establishment was greater under continuous resource supply compared to pulsed resource supply, likely because more soil resources were available at a shallow depth when resources were supplied at a continuous low rate. These results suggest that the establishment of invasive annual grasses in arid systems can be influenced by the magnitude and spatial distribution of resource pulses in addition to the seasonal timing of resource pulses. r 2006 Elsevier Ltd. All rights reserved.
Populations are locally adapted when populations have the highest relative fitness at their home sites, and lower fitness in other parts of the range. Results from the extensive experimental plantations of populations of forest trees from different parts of the range show that populations can survive and grow in broad areas outside the home site. However, intra- and interspecific competition limit the distribution of genotypes. For populations from large parts of the range, relative fitness, compared with the local population, is often highest at the home site. At the edges of the range, this local adaptation may break down. The extent of local adaptation is determined by the balance between gene flow and selection. Genetic differentiation and strong natural selection occur over a range of tens or hundreds of kilometers, but reliable measurements of gene flow are available only for much shorter distances. Current models of spatially varying selection could be made more realistic by the incorporation of st...
With a simple model, I show that comparisons of invasibility between regions are impossible to make unless one can control for all of the variables besides invasibility that influence exotic richness, including the rates of immigration of species and the characteristics of the invading species themselves. Using data from the literature for 184 sites around the world, I found that nature reserves had one-half of the exotic fraction of sites outside reserves, and island sites had nearly three times the exotic fraction of mainland sites. However, the exotic fraction and the number of exotics were also dependent on site area, and this had to be taken into account to make valid comparisons between sites. The number of native species was used as a surrogate for site area and habitat diversity. Nearly 70% of the variation in the number of exotic species was accounted for by a multiple regression containing the following predictors: the number of native species, whether the site was an island or on the mainland, and whether or not it was a nature reserve. After controlling for scale, there were significant differences among biomes, but not continents, in their level of invasion. Multiple biome regions and temperate agricultural or urban sites were among the most invaded biomes, and deserts and savannas were among the least. However, there was considerable within-group variation in the mean degree of invasion. Scale-controlled analysis also showed that the New World is significantly more invaded than the Old World, but only when site native richness (probably a surrogate for habitat diversity) is factored out. Contrary to expectation, communities richer in native species had more, not fewer, exotics. For mainland sites, the degree of invasion increased with latitude, but there was no such relationship for islands. Although islands are more invaded than mainland sites, this is apparently not because of low native species richness, as the islands in this data set were no less rich in native species than were mainland sites of similar area. The number of exotic species in nature reserves increases with the number of visitors. However, it is difficult to draw conclusions about relative invasibility, invasion potential, or the roles of dispersal and disturbance from any of these results. Most of the observed patterns here and in the literature could potentially be explained by differences between regions in species properties, ecosystem properties, or propagule pressure.
Question
Does interspecific variation in leaf phenology among grassland species help to explain the differences in species'performance under contrasting disturbance regimes.
Location
Merishausen, northern Switzerland.
Methods
Seasonal variations in leaf production and mortality were assessed for three species of nutrient‐poor limestone grasslands: Brachypodium pinnatum, Bromus erectus and Salvia pratensis ; each of these species tends to become dominant under a contrasting form of management. Their phenological characteristics were compared with their performance in plots differently managed for 21 years: (1) mowing in July; (2) mowing in October; (3) controlled burning in February; and (4) no biomass removal.
Results
The species‐specific phenological patterns of leaf production and leaf mortality are associated with the abundance of the three species under the different management regimes. B. erectus , with relatively short‐lived leaves and leaf production late in the season dominates plots mown annually in June; it has almost disappeared from plots with winter burning. B. pinnatum , with production maxima of the long‐lived leaves early in the season, does not tolerate June mowing but is most abundant in plots burnt in winter when the species has no living leaves. S. pratensis , a species with long‐lived leaves but fast senescence of all the leaves in autumn, dominates plots mown in October. In unmown plots, all species are equally abundant.
Conclusions
The seasonal pattern of leaf production and mortality strongly influence biomass and nutrient loss due to the management, and the growth that can be realized between the disturbances. A species may become dominant if it ‘fits’into the particular management regime, whereas a mismatch between phenological pattern and disturbance regime leads to its elimination from the community.
Summary 1. Climate change has already caused distribution shifts in many species, and climate predictions strongly suggest that these will accelerate in the future. Obtaining reliable predictions of species range shifts under climate change is thus currently one of the most crucial challenges for both ecologists and stakeholders. 2. Here we simulate the distributions of 16 North American tree species at a continental scale for the 21st century according to two IPCC storylines, using a process-based species distribution model that for the first time allows identification of the possible causes of distribution change. 3. Our projections show local extinctions in the south of species ranges (21% of the present distribution, on average), and colonizations of new habitats in the north, though these are limited by dispersal ability for most species. Areas undergoing local extinctions are slightly larger under climate scenario A2 (+3.2 ° C, +22% on average) than B2 (+1.0 ° C, +19% on average). This small difference is caused by nonlinear responses of processes (leaves and flowers phenological processes in particular) to temperature. We also show that local extinction may proceed at a slower rate than forecasted so far. 4. Although predicted distribution shifts are very species-specific, we show that the loss of habitats southward will be mostly due to increased drought mortality and decreased reproductive success, while northward colonizations will be primarily promoted by increased probability of fruit ripening and flower frost survival. 5. Synthesis . Our results show that different species will not face the same risks due to climate change, because their responses to climate differ as well as their dispersal rate. Focusing on processes, our study therefore tempers the alarming conclusions of widely used niche-based models about biodiversity loss, mainly because our predictions take into account the local adaptation and trait plasticity to climate of the species.
Climate change impacts on vegetation are mediated by soil processes that regulate rhizosphere water balance, nutrient dynamics, and ground-level temperatures. For ecosystems characterized by high fine-scale substrate heterogeneity such as grasslands on poorly developed soils, effects of climate change on plant communities may depend on substrate properties that vary at the scale of individuals (<m2), leading to fine-scale shifts in community structure that may go undetected at larger scales. Here, we show in a long-running climate experiment in species-rich limestone grassland in Buxton, England (UK), that the resistance of the community to 15-year manipulations of temperature and rainfall at the plot scale (9 m2) belies considerable community reorganization at the microsite (100 cm2) scale. In individual models of the abundance of the 25 most common species with respect to climate treatment and microsite soil depth, 13 species exhibited significant soil depth affinities, and nine of these have shifted their position along the depth gradient in response to one or more climate treatments. Estimates of species turnover across the depth gradient reviewed in relation to measurements of water potential, nitrogen supply, pH, and community biomass suggest that communities of shallow microsites are responding directly to microenvironmental changes induced by climate manipulation, while those of the deepest microsites are shifting in response to changes in competitive interference from more nutrient-demanding species. Moreover, for several species in summer drought and winter heated treatments, climate response in deep microsites was opposite that of shallow microsites, suggesting microsite variation is contributing to community stability at the whole-plot level. Our study thus demonstrates a strong link between community dynamics and substrate properties, and suggests ecosystems typified by fine-scale substrate heterogeneity may possess a natural buffering capacity in the face of climate change.
Aim We examined whether species occurrences are primarily limited by physiological tolerance in the abiotically more stressful end of climatic gradients (the asymmetric abiotic stress limitation (AASL) hypothesis) and the geographical predictions of this hypothesis: abiotic stress mainly determines upper-latitudinal and upper-altitudinal species range limits, and the importance of abiotic stress for these range limits increases the further northwards and upwards a species occurs.
Location Europe and the Swiss Alps.
Methods The AASL hypothesis predicts that species have skewed responses to climatic gradients, with a steep decline towards the more stressful conditions. Based on presence-absence data we examined the shape of plant species responses (measured as probability of occurrence) along three climatic gradients across latitudes in Europe (1577 species) and altitudes in the Swiss Alps (284 species) using Huisman-Olff-Fresco, generalized linear and generalized additive models.
Results We found that almost half of the species from Europe and one-third from the Swiss Alps showed responses consistent with the predictions of the AASL hypothesis. Cold temperatures and a short growing season seemed to determine the upper-latitudinal and upper-altitudinal range limits of up to one-third of the species, while drought provided an important constraint at lower-latitudinal range limits for up to one-fifth of the species. We found a biome-dependent influence of abiotic stress and no clear support for abiotic stress as a stronger upper range-limit determinant for species with higher latitudinal and altitudinal distributions. However, the overall influence of climate as a range-limit determinant increased with latitude.
Main conclusions Our results support the AASL hypothesis for almost half of the studied species, and suggest that temperature-related stress controls the upper-latitudinal and upper-altitudinal range limits of a large proportion of these species, while other factors including drought stress may be important at the lower range limits.
Native plant species are routinely planted or sown in ecological restoration projects, but successful establishment and survival depend on where and how seeds are collected. Research suggests that it is important to use locally adapted seeds. Local populations often show a home-site advantage and non-local genotypes may be maladapted to local environmental conditions. Furthermore, intraspecific hybridisation of local and non-local genotypes may have a negative impact on the genetic structure of local populations via mechanisms such as outbreeding depression. Many species show a strong small-scale genetic differentiation between different habitats so that matching habitats of the restoration and donor site can be more important than minimizing geographical separation. It is a challenge to identify appropriate seed sources because strong small-scale population differentiation makes it difficult to delineate geographically defined seed zones to which seed exchange should be limited. Moreover, it is important to consider the genetic diversity of introduced material because it may be crucial to avoid genetic bottlenecks, inbreeding depression and poor establishment of plant populations. Repeated propagation in stock, which is often required to obtain a sufficient amount of seeds, can further reduce genetic diversity and may select for particular genotypes. Negative impacts of improper seed choice for nursery planting stock may become detectable only after many years, especially in long-lived and slow growing plants. Although scientific information on many species remains limited, the increasing demand for translocation of seed means that mandatory regulations are necessary. Guidelines should prescribe a specification of seed provenance, a record of genetic diversity of wild collections and rules for subsequent processing such as direct transfer and propagation of stock or seed orchards. We use a literature review to evaluate current legislation and to develop recommendations for herbaceous and woody species.ZusammenfassungEs ist heute gängige Praxis, heimische Pflanzenarten zu Renaturierungszwecken auszubringen. Die erfolgreiche Etablierung hängt jedoch davon ab, wie und wo das Saat- oder Pflanzgut gewonnen wurde. Forschungsergebnisse legen nahe, dass nur lokal angepasste Herkünfte eingesetzt werden sollten. Es ist vielfach festgestellt worden, dass sie eine höhere Fitness als fremde Herkünfte besitzen, und letztere sind daher schlecht an lokale Umweltbedingungen angepasst. Eine intraspezifische Hybridisierung mit gebietsfremden Populationen kann weiterhin einen negativen Einfluss auf die genetische Struktur von lokalen Populationen haben wie z.B. outbreeding depression. Einige Arten zeigen eine starke kleinräumige genetische Differenzierung zwischen verschiedenen Habitaten, so dass die Übereinstimmung von Spender- und Renaturierungsflächen wichtiger sein kann als eine minimale Entfernung. Diese kleinräumige Differenzierung macht es schwierig, geographische Regionen festzulegen, innerhalb derer ein Austausch von Pflanzenmaterial unbedenklich ist. Darüber hinaus muss die genetische Diversität des gesammelten und eingeführten Materials berücksichtigt werden, um genetische Flaschenhälse, Inzuchtdepression und eine geringe Etablierungsrate zu vermeiden. Eine wiederholte Kultivierung und Vermehrung von Pflanzenarten, die oft notwendig ist, um eine ausreichende Samenmenge zu produzieren, kann zu einer weiteren Reduktion der genetischen Diversität beitragen oder zu einer Selektion bestimmter Genotypen führen. Negative Auswirkungen einer ungeeigneten Auswahl von Herkünften werden insbesondere bei langlebigen und langsam wachsenden Arten häufig erst nach vielen Jahren feststellbar. Angesichts des wachsenden Bedarfs an Wildpflanzensaatgut sind verbindliche Regelungen notwendig, auch wenn die Datenlage für viele Arten immer noch unzureichend ist. Diese Richtlinien sollten Vorgaben zur Herkunft und Diversität des Saatgutes bei der Sammlung am natürlichen Standort machen und die nachfolgende Prozesskette von der Saatgutreinigung und Lagerung über die Vermehrung bis hin zur Ausbringung regeln. Unter Verwendung von Literaturdaten bewerten wir die gegenwärtige Gesetzgebung und entwickeln Empfehlungen sowohl für krautige Pflanzen als auch für Gehölze.
Invasion by exotic annual grasses is one of the most significant threats to arid ecosystems in the western USA. Current theories of invasibility predict plant communities become more susceptible to invasion whenever there is an increase in the amount of unused resources. The objective of this field study was to examine how resource pulses and temporal variation in resource demand by the native shrub vegetation influences establishment of the invasive annual grass Schismus arabicus. Water and nitrogen were applied as pulses in early spring, mid-spring, or continuously throughout the growing season to plots containing either Atriplex confertifolia or Atriplex parryi shrubs. The effect of resource pulses on Schismus density and biomass was highly dependent on the seasonal timing of the resource pulses and the identity of the neighbor shrub. When resource pulses coincided with high rates of resource capture and growth of the native vegetation, density and biomass of Schismus was reduced. Schismus establishment was greater under continuous resource supply compared to pulsed resource supply, likely because more soil resources were available at a shallow depth when resources were supplied at a continuous low rate. These results suggest that the establishment of invasive annual grasses in arid systems can be influenced by the magnitude and spatial distribution of resource pulses in addition to the seasonal timing of resource pulses.
Winter ecological processes are important drivers of vegetation and ecosystem functioning in temperate ecosystems. There, winter conditions are subject to rapid climate change. The potential loss of a longer-lasting snow cover with implications to other plant-related climate parameters and overwintering strategies make the temperate zone particularly vulnerable to winter climate change. A formalized literature search in the ISI Web of Science shows that plant related research on the effects of winter climate change is generally underrepresented. Temperate regions in particular are rarely studied in this respect, although the few existing studies imply strong effects of winter climate change on species ranges, species compositions, phenology, or frost injury. The generally positive effect of warming on plant survival and production may be counteracted by effects such as an increased frost injury of roots and shoots, an increased insect pest risk, or a disrupted synchrony between plants and pollinators. Based on the literature study, gaps in current knowledge are discussed. Understanding the relative effects of interacting climate parameters, as well as a stronger consideration of shortterm events and variability of climatic conditions is urgent. With respect to plant response, it would be particularly worthwhile to account for hidden players such as pathogens, pollinators, herbivores, or fungal partners in mycorrhization.
Two different UK limestone grasslands were exposed to simulated climate change with the use of nonintrusive techniques to manipulate local climate over 5 years. Resistance to climate change, defined as the ability of a community to maintain its composition and biomass in response to environmental stress, could be explained by reference to the functional composition and successional status of the grasslands. The more fertile, early-successional grassland was much more responsive to climate change. Resistance could not be explained by the particular climates experienced by the two grasslands. Productive, disturbed landscapes created by modern human activity may prove more vulnerable to climate change than older, traditional landscapes.
Global environmental change is altering the selection regime for all biota. The key selective factors are altered mean, variance and seasonality of climatic variables and increase in CO(2) concentration itself. We review recent studies that document rapid evolution to global climate change at the phenotypic and genetic level, as a response to shifts in these factors. Among the traits that have changed are photoperiod responses, stress tolerance and traits associated with enhanced dispersal. The genetic basis of two traits with a critical role under climate change, stress tolerance and photoperiod behaviour, is beginning to be understood for model organisms, providing a starting point for candidate gene approaches in targeted nonmodel species. Most studies that have documented evolutionary change are correlative, while selection experiments that manipulate relevant variables are rare. The latter are particularly valuable for prediction because they provide insight into heritable change to simulated future conditions. An important gap is that experimental selection regimes have mostly been testing one variable at a time, while synergistic interactions are likely under global change. The expanding toolbox available to molecular ecologists holds great promise for identifying the genetic basis of many more traits relevant to fitness under global change. Such knowledge, in turn, will significantly advance predictions on global change effects because presence and polymorphism of critical genes can be directly assessed. Moreover, knowledge of the genetic architecture of trait correlations will provide the necessary framework for understanding limits to phenotypic evolution; in particular as lack of critical gene polymorphism or entire pathways, metabolic costs of tolerance and linkage or pleiotropy causing negative trait correlations. Synergism among stressor impacts on organismal function may be causally related to conflict among transcriptomic syndromes specific to stressor types. Because adaptation to changing environment is always contingent upon the spatial distribution of genetic variation, high-resolution estimates of gene flow and hybridization should be used to inform predictions of evolutionary rates.
Winterclimatechange:acriticalfactorfortemperatevegeta-tionperformance
- J Kreyling
Kreyling,J.(2010)Winterclimatechange:acriticalfactorfortemperatevegeta-tionperformance.Ecology,91,1939–1948
The Analysis of Variance: Fixed, Random and Mixed Models Responses of alpine snowbed vegetation to long-term experimental warming
- H Sahai
- M I Ageel
- Birkhaü
- Boston
- S M Sandvik
- E Heegaard
- R Elven
- V Vandvik
Sahai, H. & Ageel, M.I. (2000) The Analysis of Variance: Fixed, Random and Mixed Models. Birkhaü, Boston. Sandvik, S.M., Heegaard, E., Elven, R. & Vandvik, V. (2004) Responses of alpine snowbed vegetation to long-term experimental warming. Ecoscience, 11, 150–159.
Comparative Plant Ecology: A Functional Approach to Common British Species, 2nd edn The response of two contrasting limestone grasslands to simulated climate change
- J P Grime
- J G Hodgson
- R Hunt
- Delbeattie
- J P Grime
- V K Brown
- K Thompson
- G J Masters
- S H Hillier
- I P Clarke
- A P Askew
- D Corker
- J P Kielty
Grime, J.P., Hodgson, J.G. & Hunt, R. (2007) Comparative Plant Ecology: A Functional Approach to Common British Species, 2nd edn. Castlepoint Press, Delbeattie. Grime, J.P., Brown, V.K., Thompson, K., Masters, G.J., Hillier, S.H., Clarke, I.P., Askew, A.P., Corker, D. & Kielty, J.P. (2000) The response of two contrasting limestone grasslands to simulated climate change. Science, 289, 762–765.
(in press) Soil heterogeneity buffers community response to climate change in species-rich grassland Is evolution necessary for range expan-sion? Manipulating reproductive timing of a weedy annual transplanted beyond its range
- J D Fridley
- J P Grime
- A P Askew
- B Moser
- C J Stevens
Fridley, J.D., Grime, J.P., Askew, A.P., Moser, B. & Stevens, C.J. (in press) Soil heterogeneity buffers community response to climate change in species-rich grassland. Global Change Biology, doi: 10.1111/j.1365-2486.2010.02347.x. Griffith, T.M. & Watson, M.A. (2006) Is evolution necessary for range expan-sion? Manipulating reproductive timing of a weedy annual transplanted beyond its range. American Naturalist, 167, 153–164.
A meta-analysis of the response of soil respiration, net nitrogen mineralization, and aboveground plant growth to experimental ecosystem warming
- Rustad