Occurrence of the Rare Fish Lobotes surinamensis (Bloch, 1790) in the Capo Peloro Lagoon (Central Mediterranean Sea): Some Implications

During community assembly, early arriving exotic species might suppress other species to a greater extent than do native species. Because most exotics were intentionally introduced, we hypothesize there was human selection on regeneration traits during introduction. This could have occurred at the across- or within-species level (e.g. during cultivar development). We tested these predictions by seeding a single species that was either native, exotic 'wild-type' (from their native range), or exotic 'cultivated' using 28 grassland species in a glasshouse experiment. Priority effects were assessed by measuring species' effect on establishment of species from a seed mix added 21 d later. Exotic species had higher germination and earlier emergence dates than native species, and differences were found in both 'wild' and 'cultivated' exotics. Exotic species reduced biomass and species diversity of later arriving species much more than native species, regardless of seed source. Results indicate that in situations in which priority effects are likely to be strong, effects will be greater when an exotic species arrives first than when a native species arrives first; and this difference is not merely a result of exotic species cultivation, but might be a general native-exotic difference that deserves further study.

Trait divergence and the ecosystem impacts of invading species

Invited article: The impacts of non‐native species: a review of the British Ornithologists’ Union's Autumn 2008 Scientific Meeting

Exotic fast-growing tree species have been commonly planted as pioneer species to facilitate ecological restoration in South China. Their growth and resource utilization behavior related to intrinsic physiology and structural properties have profound influences on forest ecosystem. However, the contrastive research focusing on water utilization features along with xylem anatomical properties between native and exotic species is scarce in South China. The objective of this study is to investigate the sapwood anatomical characteristics and water utilization conditions of native and exotic fast-growing species, and to elucidate the relationship between sap-flux density and conduit features. We measured sap-flux density, conduit length, diameter and density of four native species (Schima superba, Michelia macclurei, Castanopsis hystrix and Castanopsis fissa) and four exotic species (Eucalyptus citriodora, Eucalyptus urophylla × grandis, Acacia auriculaeformis and Acacia mangium). Sap flux density was measured based on the Granier’s thermal dissipation probe method. The whole-tree water transport was quantified by multiplying sap-flux density by sapwood area. The measurements of conduit characteristics were conducted by using segregation and slice method. Sapwood area increased with the growing diameter at breast height (DBH) as a power function. Native species had a larger water-conducting tissue area than exotic species at the same DBH value when trees grew to a size with a certain value of DBH. The conduit diameter of exotic species was significantly larger than that of native species. Conversely, native species, such as S. superba and M. macclurei, had longer conduit length and higher conduit density than other tree species. Based on a physiological interpretation of the measured conduit characteristics, native tree species developed a safe water transport system while exotic fast-growing tree species come into being an efficient system instead. Water transport increased with the growing DBH as a power function, and the exponent for native species (1.60) was higher than that for exotic species (1.22). Under the combined impact of sap-flux density and sapwood area, native species presented a larger water transport at a larger DBH value, indicating that growth advantage of exotic fast-growing species might weaken as DBH increased.

Life-history traits of invasive exotic plants are typically considered to be exceptional vis-à-vis native species. In particular, hyper-fecundity and long range dispersal are regarded as invasive traits, but direct comparisons with native species are needed to identify the life-history stages behind invasiveness. Until recently, this task was particularly problematic in forests as tree fecundity and dispersal were difficult to characterize in closed stands. We used inverse modelling to parameterize fecundity, seed dispersal and seedling dispersion functions for two exotic and eight native tree species in closed-canopy forests in Connecticut, USA. Interannual variation in seed production was dramatic for all species, with complete seed crop failures in at least one year for six native species. However, the average per capita seed production of the exotic Ailanthus altissima was extraordinary: > 40 times higher than the next highest species. Seed production of the shade tolerant exotic Acer platanoides was average, but much higher than the native shade tolerant species, and the density of its established seedlings (≥ 3 years) was higher than any other species. Overall, the data supported a model in which adults of native and exotic species must reach a minimum size before seed production occurred. Once reached, the relationship between tree diameter and seed production was fairly flat for seven species, including both exotics. Seed dispersal was highly localized and usually showed a steep decline with increasing distance from parent trees: only Ailanthus altissima and Fraxinus americana had mean dispersal distances > 10 m. Janzen-Connell patterns were clearly evident for both native and exotic species, as the mode and mean dispersion distance of seedlings were further from potential parent trees than seeds. The comparable intensity of Janzen-Connell effects between native and exotic species suggests that the enemy escape hypothesis alone cannot explain the invasiveness of these exotics. Our study confirms the general importance of colonization processes in invasions, yet demonstrates how invasiveness can occur via divergent colonization strategies. Dispersal limitation of Acer platanoides and recruitment limitation of Ailanthus altissima will likely constitute some limit on their invasiveness in closed-canopy forests.

Quantitative integration of factors that potentially affect exotic species richness and abundance at multiple spatial scales is relatively scarce in the literature. Our aim was to address this gap by evaluating the relative importance of the biotic community, abiotic factors, and landscape characteristics on the establishment and spread of native and exotic plant species. We assessed the effect of these factors on exotic and native species richness and abundance, and used regression tree and variation partitioning analyses to evaluate how these predictors interact to favor or limit exotic and/or native species. We found that landscape filters were especially important for the arrival of both native and exotic species, whereas biotic factors seemed to regulate the abundance of plant species once they were present within the system. However, the combined effects of different types of predictors explained the largest fraction of total variation in all models regarding exotic species. Furthermore, significant predictor variables had opposite effects on native versus exotic species at both local and landscape scales, which suggests that some ecosystem properties affect native and exotic species differently. Exotic species richness and abundance were increased by low values of native species cover and diversity, high landscape heterogeneity and edge density, human disturbances (e.g., mowing and soil disruption), land use activities (e.g., developed and agricultural areas), and proximity to transportation systems, especially highways. However, exotic species were less common in areas with low anthropogenic disturbance, where natural disturbances seemed to favor native plant species.

The amount of exotic plant species introduced to new regions by humans has considerably increased in the last two centuries. Worldwide, the invasion of exotic species represents an important threat to native biodiversity and ecosystem functions. Several biological traits (e.g., high growth rate and rapid propagation) result in a superior competitiveness of invasive species and often cause changes in natural species composition. Specifying the attributes that turn exotic species into strong competitors may improve the ability to understand and effectively manage plant invasions in the future. Conducting a pot experiment ensures the investigation of plant interactions under relatively controlled conditions without distracting effects of heterogeneous environmental factors. However, pot experiments with tree species raise more problems in comparison with herbaceous plants due to their longevity and bigger dimensions. This is shown by a comprehensive literature review giving an overview on the practical implementation of pot experiments studying exclusively tree species. It is evident that the advantage of pot experiments is also a disadvantage at the same time: Due to the controlled conditions, pot experiments are always restricted in their ability to imitate natural situations. Thus, the reliability of pot studies for predicting the growth and performance of trees in the field can be problematic. One option to improve the transferability of pot experiments could be to implement additional measurements under natural conditions. In a pot experiment, I investigated the competition mechanisms due to differences in growth rate, biomass production, and biomass allocation of two native (Quercus robur L., Carpinus betulus L.) and two exotic tree species (Prunus serotina Ehrh., Robinia pseudoacacia L.). One-year-old tree seedlings were planted in different intra- and interspecific, competitive situations with or without the influence of root competition. To determine the competition mechanisms in more detail, I distinguished between root and shoot competition by installing either above- or belowground plastic partitions in the pots. I hypothesized that total biomass production of the exotic tree species is significantly higher compared to the native species resulting in a biomass reduction of Q. robur and C. betulus. Furthermore, I analyzed the effect of belowground competition on native plant performance and biomass allocation patterns according to the ‘balanced-growth hypothesis’. The results supported the assumptions that biomass production of exotic P. serotina and R. pseudoacacia is significantly higher, which leads to a strong competitive advantage and to a biomass decrease of the admixed less competitive native species. The competitive pressure of exotic tree seedlings on Q. robur and C. betulus was largely driven by root competition. The exclusion of belowground interactions by partitions led to an increasing biomass production of both native species. Thus, even a limited rooting volume seemed to provide better growing conditions than direct root interactions by invasive competitors. In accordance with the ‘balanced-growth hypothesis’, Q. robur and C. betulus allocated more biomass towards the roots due to the strong effect of belowground competition by exotic species. The higher proportion of the root fraction was mainly achieved at the expense of leaf and branch biomass. Furthermore, the results showed a higher biomass production in mixtures of native and exotic tree species than their growth in monocultures would have predicted. Competition was lower for exotic species in mixtures with the less productive Q. robur and C. betulus compared to the competition in monocultures or in mixture with the other exotic species. Regarding both exotic species, P. serotina produced a significantly higher biomass. Nevertheless, R. pseudoacacia negatively affected the biomass production of P. serotina due to its strong root competition. Accordingly, both highly competitive exotic species inhibited each other’s growth and produced less biomass in mixture with each other compared to the respective monocultures. There is evidence that the strong competitiveness of invasive exotic species is often achieved at the expense of a tolerance to environmental stress. Accordingly, both exotic species had a higher mortality rate in the pot experiment and especially P. serotina seemed to be sensitive to shade, drought, and flooding. Possibly, this weakness could be used to prevent a further spreading of invasive species.

Networks of protected areas are fundamental for biodiversity conservation, but many factors determine their conservation efficiency. In particular, on top of other human-driven disturbances, invasions by non-native species can cause habitat and biodiversity loss. Jointly understanding what drives patterns of plant diversity and of non-native species in protected areas is therefore a priority. We tested whether the richness and composition of native and non-native plant species within a network of protected areas follow similar patterns across spatial scales. Specifically, we addressed three questions: (a) what is the degree of congruence in species richness between native and non-native species? (b) do changes in the composition of non-native species across ecological gradients reflect a similar turnover of native species along the same gradients ? (c) what are the main environmental and human disturbance drivers controlling species richness in these two groups of species? Species richness and composition of native and non-native plant species were compared at two spatial scales: the plot scale (10 m × 10 m) and the Protected Area scale (PA). In addition, we fit Generalized Linear Models to identify the most important drivers of native and non-native species richness at each scale, focusing on environmental conditions (climate, topography) and on the main sources of human disturbance in the area (land use and roads). We found a significant positive correlation between the turnover of native and non-native species composition at both plot and PA scales, whereas their species richness was only correlated at the larger PA scale. The lack of congruence between the richness of native and non-native species at the plot scale was likely driven by differential responses to fine scale environmental factors, with non-natives favoring drier climates and milder slopes (climate and slope). In addition, more non-native species were found closer to road-ways in the reserve network. In contrast, the congruence in the richness of native and non-native species at the broader PA scale was mainly driven by the common influence of PA area, but also by similar responses of the two groups of species to climatic heterogeneity. Thus, our study highlights the strong spatial dependence of the relationship between native and non-native species richness and of their responses to environmental variation. Taken together, our results suggest that within the study region the introduction and establishment of non-native species would be more likely in warmer and dryer areas, with high native species richness at large spatial scale but intermediate levels of anthropogenic disturbances and mild slope inclinations and elevation at fine scale. Such an exhaustive understanding of the factors that influence the spread of non-native species, especially in networks of protected areas is crucial to inform conservation managers on how to control or curb non-native species.

The introduction of alien species represents one of the greatest threats to biodiversity worldwide. Highway construction increases the dispersal and invasion of exotic plant species. This study examined the assembly process of the plant communities to determine whether the roadsides of the Patagonian steppe represent a reservoir and dispersal source of invasive exotic species. We analyzed the composition of exotic and native species and functional groups present in the established vegetation and seed banks of roadsides and reference areas nearby. The type of dispersal of exotic and native species at the roadsides was also evaluated. Total cover and that of exotic and native species was lower at the roadsides than in the reference areas; however, at the roadsides the cover and seed abundance of exotic species was higher than that of native species. In the roadsides vegetation, native shrubs such as Acaena splendens predominated, along with exotic perennial herbs and grasses which were mainly represented by Rumex acetosella. In the seed bank the predominant species were exotic perennial herbs, also represented by R. acetosella, annual exotic species such as Epilobium brachycarpum and Verbascum thapsus, and annual native species such as Heliotropium paronychioides. No exotic shrubs were found either at the roadsides or in the reference areas. The species at the roadsides did not present a dominant type of dispersal. The abundance of exotic species at the roadsides, both in the aboveground vegetation and the seed bank, may be due to the stressful environment and the characteristics of the species themselves, such as the ability to form seed banks. This work revealed that the roadsides of the Patagonian steppe constitute reservoirs of invasive exotic species, highlighting the importance of identifying them and controlling their spread, with a view to generating ecosystem management programs.

Summary Plant species can influence soil biota, which in turn can influence the relative performance of plant species. These plant–soil feedbacks (PSFs) have been hypothesized to affect many community‐level dynamics including species coexistence, dominance and invasion. The importance of PSFs in exotic species invasion, although widely hypothesized, has been difficult to determine because invader establishment necessarily precedes invader‐mediated PSFs. Here, we combine a spatial simulation model of invasion that incorporates PSFs with a meta‐analysis that synthesizes published case studies describing feedbacks between pairs of native and exotic species. While our spatial model confirmed the link between positive soil feedbacks (‘home’ advantage) for exotic species and exotic species spread, results were dependent on the initial abundance of the exotic species and the equivalence of dispersal and life history characteristics between exotic and native species. The meta‐analysis of 52 native–exotic pairwise feedback comparisons in 22 studies synthesized measures of native and exotic performance in soils conditioned by native and exotic species. The analysis indicated that the growth responses of native species were often greater in soil conditioned by native species than in soil conditioned exotic species (a ‘home’ advantage). The growth responses of exotic species were variable and not consistently related to species soil‐conditioning effects. Synthesis. Overlaying empirical estimates of pairwise PSFs with spatial simulations, we conclude that the empirically measured PSFs between native and exotic plant species are often not consistent with predictions of the spread of exotic species and mono‐dominance. This is particularly the case when exotic species are initially rare and share similar dispersal and average fitness characteristics with native species. However, disturbance and other processes that increase the abundance of exotic species as well as the inclusion of species dispersal and life history differences can interact with PSF effects to explain the spread of invasive species.

<p>Coastal environments are exposed to anthropogenic activities such as frequent marine traffic and restructuring, i.e., addition, removal or replacing with man-made structures. Although maritime shipping and coastal infrastructures provide socio-economic benefits, they both cause varied perturbations to marine ecosystems. The ports and marinas receiving a high frequency of international vessels, act as ‘hot-spots’ for marine invasions. The disturbed and modified habitats found in harbours and ports provide opportunities for non-native species to settle due to their competitive traits. Once established, the non-native species may spread to neighbouring habitats, thereby modifying the adjacent natural environment, its biodiversity, ecosystem structure and functioning. Up to 70% of coastlines around the world have now been modified and is expected to rise in future. New bioinvasions are still being reported even with various biosecurity and management approaches across the globe. It is essential to understand the potential factors influencing the bioinvasions to have effective biosecurity measures and management plans. The overall aim of this thesis is to determine the influence of man-made structures on the marine biodiversity and presumptive fitness of native and non-native species on these structures. This thesis investigates ports and harbours as man-made environments, their impacts on marine biodiversity and the species status – native, non-native and cryptogenic, and the factors facilitating the spread of non-native species. Chapter 2 focussed on two large national-scale baseline port surveys; a) Australian Port Survey (APS), and b) New Zealand Port Survey (NZPS). The two datasets were analysed to determine the community structure and species status, i.e., native, non-native and cryptogenic as a function of the surveyed ports, port type (major vs minor ports) (based on the volume of vessels) and latitudinal groups. A) APS: The results for community composition indicated significant effects as a function of surveyed ports, port type and latitudinal group. The community composition was relatively more abundant at major ports than at minor ports. The factor, the latitudinal group indicated significant results, and a distinct separation in community composition was observed between low (15, 20oS) and high (35, 40oS) latitudes. The species status showed a significant and positive relationship between native vs non-native, indicating with an increase in the number of native species there was an increase in the number of non-native species. The species status indicated significant results for the factors; surveyed ports, port type and latitudinal group. The native species were abundant throughout the study. However, the non-native species were relatively abundant at major ports compared to minor ports. Regarding the latitudinal groups, the abundance of non-native species was observed to increase at higher latitudes (latitudinal gradients). B) NZPS: The community composition and species status showed significance among the 27 surveyed ports; however, no significant results were observed for the factor port type (major vs minor). The community composition significantly varied as a function of latitudinal groups, with species at higher latitudes (45oS) being better discriminator explaining the differences. Latitudinal groups, however, highlighted sub-groupings of ports with similar community composition (e.g. Bluff and Dunedin; Nelson, Wellington and Picton; Lyttelton and Timaru; Whangarei, Tauranga and Taranaki; Auckland, Gulf Harbour Marina and Opua Marina). The ports in question are within close proximity of each other (distance). This suggests the possibility of natural dispersal of species between ports on top of the human-mediated dispersal. The responses in Australia were very different from those in New Zealand, which suggests that the responses are regional or country-specific and not global. Chapter 3 describes fieldwork using settlement tile arrays to examine the effects of man-made built structures and natural rocky reefs on marine biological community composition and successional patterns over two years. The work also tests the preference of native and non-native species in terms of habitat type (natural reef vs man-made habitat) and substratum type (PVC vs slate tile). The results showed a rapid increase in species settlement on bare tiles as the available bare space was 30% just after 3 months of submersion. The community composition significantly differed as a function of the interaction of factors, habitat × substratum × sample interval. However, differences between the habitat types and substratum types, respectively, were explained by the difference in abundance of the same suite of species. The species were abundant at marina sites compared to reef sites; however, in terms of substrata, the species were abundant on slate (natural) tiles than on PVC tiles. The succession patterns of species over time (8 sample intervals) showed a similar trend on both the habitat type and substratum type, with differences in the average abundances of each species. The differences in abundances highlight the influence of species dispersal patterns, recruitment patterns and post-settlement processes of species between habitat type and substratum type, respectively. Subsequently, the species status indicated significance as a function of habitat type, substratum type and sample intervals. The cryptogenic species were abundant throughout the study. The cryptogenic species, however, decreased in abundance over time, with an increase in abundance of native and non-native species. Subsequently, the non-native species significantly varied between habitat type, with relatively higher abundance at marina (man-made) sites compared to reef (natural) sites. However, the non-native species did not show significant variation as a function of substratum type (PVC vs slate). The results are discussed in the context of the recruitment of species on a new barren substrate, and the preference of habitat type and substratum type by native, non-native and cryptogenic species. In Chapter 4, the reproduction output (gonadosomatic index, GSI) of the Southern hemisphere, native (SHMg) and Northern hemisphere, non-native (NHMg) lineages of the blue mussel, Mytilus galloprovincialis were measured. The GSI and shell length of NHMg and SHMg were compared between habitat type; reef (natural) vs marina (man-made) sites. This study aimed to identify reproductive patterns (i.e., timing and magnitude of spawning events) and differences in performance (presumptive fitness) of the native and non-native blue mussel lineages at the natural and man-made habitats. The results for shell length indicated significance for habitat type and no significance as a function of lineage. The mussels were relatively bigger mussels at marina sites compared to reef sites; however, the differences were trivial. The GSI values as a function of habitat type, lineage and sampling time showed a significant difference between habitat type, with high GSI values at reef sites than at marina sites. However, this indicates that the blue mussels at marina sites had comparatively higher spawning activity than at reef sites. The temporal variation of GSI of NHMg and SHMg showed a similar reproductive trend (i.e., spawning and gametogenesis) at both habitats. However, significant spawning activity was observed in July and November when compared between reef and marina habitats. The results are discussed in the context of management implications and strategies regarding the establishment and success of non-native M. galloprovincialis lineage and whether their eradication is necessary or even possible. The findings of this research are summarised and discussed in relation to our understanding of biological community composition and diversity on man-made habitats and the subsequent invasion in the neighbouring natural habitats. This study, from an eco-engineering perspective, highlights the importance of complex habitats and surfaces, and not just material type. However, from a biosecurity and management approach, even though Australia and New Zealand have one of the strong international biosecurity country-specific legislation; the continuous arrival of non-native species in these countries indicates that such marine legislation is not sufficiently compelling on its own. This study highlights the interaction of non-native species at proximity ports, and it provides recommendations towards regional-scale management measures concentrating on intra-coastal transfer of invaders through domestic maritime traffic or natural dispersal. The life-history traits, recruitment timing and post-settlement processes, plays an essential role in determining long term patterns. Lastly, this research indicated that native and non-native species with ecologically similar responses lead to limited management options to some extent. Therefore, from a manager’s perspective, the eradication of non-native species may not be necessary if it does not cause any negative impacts to the biodiversity or the environment.</p>

Long-distance dispersal events are irregular and their role in shaping plant diversity is often discussed and modeled but rarely studied experimentally. We mimicked long-distance dispersal experimentally by sowing eleven exotic and fourteen native species into a calcareous grassland community in Estonia. Exotic species were randomly chosen from the collection of 500 herbaceous species in the Botanical Garden of the Tartu University. All exotic species were able to complete their life-cycles under the climatic and edaphic conditions in the garden. Native species originated from open dry calcareous habitats in the surroundings of the study site, but did not occur in the experimental grassland. Seven exotic species and seven native species established during the first year. In the third year, there were still three exotic species with five premature individuals, and three sown native species with sixteen individuals in the plots. These results show that long-distance dispersal both within and between regions may have an impact on species composition in target plant communities. If relatively the best established exotic speciesPhyteuma scheuchzeri would be classified as casual, one may conclude that transition among introduction and casual stages corresponds to ten’ rule. The species richness of seedlings, taking both local and sown species into account, was higher in plots with higher native established plant species richness.

Ongoing changes in Earth’s climate are shifting the elevation ranges of many plant species with non-native species often experiencing greater expansion into higher elevations than native species. These climate change-induced shifts in distributions inevitably expose plants to novel biotic and abiotic environments, including altered solar ultraviolet (UV)-B (280–315 nm) radiation regimes. Do the greater migration potentials of non-native species into higher elevations imply that they have more effective UV-protective mechanisms than native species? In this study, we surveyed leaf epidermal UV-A transmittance (TUV A) in a diversity of plant species representing different growth forms to test whether native and non-native species growing above 2800 m elevation on Mauna Kea, Hawaii differed in their UV screening capabilities. We further compared the degree to which TUV A varied along an elevation gradient in the native shrub Vaccinium reticulatum and the introduced forb Verbascum thapsus to evaluate whether these species differed in their abilities to adjust their levels of UV screening in response to elevation changes in UV-B. For plants growing in the Mauna Kea alpine/upper subalpine, we found that adaxial TUV A, measured with a UVA-PAM fluorometer, varied significantly among species but did not differ between native (mean = 6.0%; n = 8) and non-native (mean = 5.8%; n = 11) species. When data were pooled across native and non-native taxa, we also found no significant effect of growth form on TUV A, though woody plants (shrubs and trees) were represented solely by native species whereas herbaceous growth forms (grasses and forbs) were dominated by non-native species. Along an elevation gradient spanning 2600–3800 m, TUV A was variable (mean range = 6.0–11.2%) and strongly correlated with elevation and relative biologically effective UV-B in the exotic V. thapsus; however, TUV A was consistently low (3%) and did not vary with elevation in the native V. reticulatum. Results indicate that high levels of UV protection occur in both native and non-native species in this high UV-B tropical alpine environment, and that flexibility in UV screening is a mechanism employed by some, but not all species to cope with varying solar UV-B exposures along elevation gradients.

Enhanced plasticity and reproductive fitness of floral and seed traits facilitate non-native species spread in mountain ecosystems

In the coming decades, rainfall in many Mediterranean‐type ecosystems is expected to decline overall, but also become more variable interannually. Historically plant communities in these regions have been dominated by native shrubs, but are becoming increasingly invaded by exotic annual species, making it important to evaluate how native versus exotic species will respond to shifting rainfall patterns associated with climate change. Exotic species are often found to possess a suite of traits associated with fast growth and resource uptake, as well as high plasticity in traits. Hence, we hypothesized that exotic species would benefit disproportionately over native species under high rainfall conditions, while native species with more conservative growth strategies would better tolerate drought. We evaluated these expectations by manipulating rainfall (five levels, from total exclusion to a doubling of ambient rainfall) over plots containing a mix of herbaceous exotic species, mature native shrubs, and planted shrub seedlings, and measured functional trait and growth responses of focal species. We found significant variation among groups in their response to variation in rainfall quantity: growth of exotic herbaceous species was higher in response to high rainfall, and lower in response to drought, compared with native adult shrubs, with juvenile shrubs having an intermediate response. In contrast with these growth responses, functional traits of native and exotic species responded similarly to experimental variation in rainfall. Further, although we found exotic species possessed thinner leaves and higher photosynthetic capacity, neither mean trait values nor trait plasticity were predictive of species‐level responses to altered rainfall in this system. We conclude that while some functional traits often predict community composition across large environmental gradients, traits may not predict species responses to environmental change at local scales with limited species pools.