Ecosystem-based management outperforms species-focused stocking for enhancing fish populations.

Ecosystem-based management is costly. Therefore, without rigorously showing that it can outperform traditional species-focused alternatives, its broad-scale adoption in conservation is unlikely. We present a large-scale replicated and controlled set of whole-lake experiments in fish conservation (20 lakes monitored over 6 years with more than 150,000 fish sampled) to examine the outcomes of ecosystem-based habitat enhancement (coarse woody habitat addition and shallow littoral zone creation) versus a widespread, species-focused alternative that has long dominated fisheries management practice (i.e., fish stocking). Adding coarse woody habitats alone did not, on average, enhance fish abundance, but creating shallow water habitat consistently did, especially for juvenile fish. Species-focused fish stocking completely failed. We provide strong evidence questioning the performance of species-focused conservation actions in aquatic ecosystems and instead recommend ecosystem-based management of key habitats.

Biological invasions reveal how niche change affects the transferability of species distribution models.

Species distribution models (SDMs) have been widely applied to predict geographic ranges of species across space and time under the assumption of niche conservatism (i.e., species niches change very slowly). However, an increasing number of studies have reported evidence of rapid niche changes across space and time, which has sparked a widespread debate on whether SDMs can be transferred to new areas or time periods. Understanding how niche changes affect SDM transferability is thus crucial for the future application and improvement of SDMs. Biological invasions provide an opportunity to address this question due to the geographically independent distributions and diverse patterns of niche changes between species' native and introduced ranges. Here, we synthesized findings on 217 species from 50 studies to elucidate the effects of niche change on the spatial transferability of SDMs. When niche change was considered as a categorical classification (conserved vs. shifted niches) in tests of the niche conservatism hypothesis, SDM transferability was markedly lower for species with a shifted niche in their introduced range. When niche change was measured as numerical dynamics between native and introduced niches, SDM transferability was high for species occupying similar environmental conditions in both ranges and low for species with more environmental space remaining unoccupied in the introduced range. Surprisingly, the number of presence points used for developing SDMs turned out to have an even stronger effect on transferability. Our results thus reveal detrimental effects of both niche change and lack of presence points on SDM transferability. It is necessary to consider both niche change and data quality for improving the transferability of SDMs, so that they can better support conservation management and policy decisions.

Evident but context-dependent mortality of fish passing hydroelectric turbines.

Globally, policies aiming for conservation of species, free-flowing rivers, and promotion of hydroelectricity as renewable energy and as a means to decarbonize energy systems generate trade-offs between protecting freshwater fauna and development of hydropower. Hydroelectric turbines put fish at risk of severe injury during passage. Therefore, comprehensive, reliable analyses of turbine-induced fish mortality are pivotal to support an informed debate on the sustainability of hydropower (i.e., how much a society is willing to pay in terms of costs incurred on rivers and their biota). We compiled and examined a comprehensive, global data set of turbine fish-mortality assessments involving >275,000 individual fish of 75 species to estimate mortality across turbine types and fish species. Average fish mortality from hydroelectric turbines was 22.3% (95% CI 17.5-26.7%) when accounting for common uncertainties related to empirical estimates (e.g., handling- or catch-related effects). Mortality estimates were highly variable among and within different turbine types, study methods, and taxa. Technical configurations of hydroelectric turbines that successfully reduce fish mortality and fish-protective hydropower operation as a global standard could balance the need for renewable energy with protection of fish biodiversity.

Mortalidad evidente, pero dependiente del contexto, de peces que pasan por turbinas hidroeléctricas Resumen Globalmente, las políticas que buscan la conservación de especies, el flujo libre de ríos y la promoción de la hidroeléctrica como una energía renovable y como un medio para reducir el carbono en sistemas de energía generan pros y contras entre la protección de la fauna de agua dulce y el desarrollo de la hidroeléctrica. Las turbinas hidroeléctricas ponen a los peces en riesgo de heridas severas al pasar por ellas. Por lo tanto, análisis integrales, confiables de la mortalidad de peces inducida por turbinas son esenciales para sustentar un debate informado de la sustentabilidad de la energía hidroeléctrica (i. e., que tan dispuesta esta una sociedad para pagar en términos de costos incurridos en los ríos y su biota). Compilamos y examinamos un conjunto de datos integrales, globales de evaluaciones de mortalidad de peces en turbinas involucrando >275,000 peces individuales de 75 especies para estimar la mortalidad en tipos de turbinas y especies de peces. La mortalidad promedio de peces en turbinas hidroeléctricas fue 22.3% (95% IC 17.5-26.7%) cuando se consideraron incertidumbres comunes relacionadas con las estimaciones empíricas (e. g., efectos relacionados con el manejo o captura). Las estimaciones de mortalidad fueron muy variables entre y dentro de los diferentes tipos de turbinas, métodos de estudio y taxones. Las configuraciones técnicas de las turbinas hidroeléctricas que exitosamente reduzcan la mortalidad de peces y proporcionen una operación protectora de peces como un estándar global podrían equilibrar la necesidad de energía renovable con la protección de la biodiversidad de peces.

Ecological impacts of water-based recreational activities on freshwater ecosystems: a global meta-analysis.

Human presence at water bodies can have a range of ecological impacts, creating trade-offs between recreation as an ecosystem service and conservation. Conservation policies could be improved by relying on robust knowledge about the relative ecological impacts of water-based recreation. We present the first global synthesis on recreation ecology in aquatic ecosystems, differentiating the ecological impacts of shore use, (shoreline) angling, swimming and boating. Impacts were assessed at three levels of biological organization (individuals, populations and communities) for several taxa. We screened over 13 000 articles and identified 94 suitable studies that met the inclusion criteria, providing 701 effect sizes. Impacts of boating and shore use resulted in consistently negative, significant ecological impacts across all levels of biological organization. The results were less consistent for angling and swimming. The strongest negative effects were observed in invertebrates and plants. Recreational impacts on birds were most pronounced at the individual level, but not significant at the community level. Due to publication bias and knowledge gaps, generalizations of the ecological impacts of aquatic recreation are challenging. Impacts depend less on the form of recreation. Thus, selectively constraining specific types of recreation may have little conservation value, as long as other forms of water-based recreation continue.

How much habitat does a river need? A spatially-explicit population dynamics model to assess ratios of ontogenetical habitat needs.

Restoration of spawning and juvenile habitats is often used to restore fish abundances in rivers, although often with unclear results. To study the effects of habitat limitations on the common barbel (Barbus barbus), a riverine litophilic cyprinid fish, an age-structured population model was developed. Using a Bayesian modeling approach, spawning and fry (0+ juvenile) habitat availability was integrated in the model in a spatially explicit way. Using Beverton-Holt and Ricker recruitment models, density dependence was incorporated in the spawning process and the recruitment of 0+ juveniles. Model parameters and their uncertainty ranges were obtained from reviewing the existing literature. The uncertainty of the processes was intrinsically accounted for by the inherently probabilistic nature of the Bayesian model. By testing various scenarios of habitat availabilities for the barbel, we hypothesize that improvement of the fish stock will be reached only at a well specified ratio of spawning to fry habitat. Model simulations revealed substantial abundance improvements at rather equal amounts of about 10% cover of both habitats, while even substantial improvements of either spawning or fry habitats only will result in little or no increase of abundance. Higher ratios of spawning to fry habitat were found to lower population recovery times. This work provides a tool that serves the assessment and comparison of river restoration scenarios as well as benchmarking rehabilitation targets in the planning phase. When targeting restoration of fish stocks, focusing only on one key life stage or process (such as spawning), without considering potential bottlenecks in other stages, can result in little to no improvement.

Expanding conservation culturomics and iEcology from terrestrial to aquatic realms.

The ongoing digital revolution in the age of big data is opening new research opportunities. Culturomics and iEcology, two emerging research areas based on the analysis of online data resources, can provide novel scientific insights and inform conservation and management efforts. To date, culturomics and iEcology have been applied primarily in the terrestrial realm. Here, we advocate for expanding such applications to the aquatic realm by providing a brief overview of these new approaches and outlining key areas in which culturomics and iEcology are likely to have the highest impact, including the management of protected areas; fisheries; flagship species identification; detection and distribution of threatened, rare, and alien species; assessment of ecosystem status and anthropogenic impacts; and social impact assessment. When deployed in the right context with awareness of potential biases, culturomics and iEcology are ripe for rapid development as low-cost research approaches based on data available from digital sources, with increasingly diverse applications for aquatic ecosystems.

Most invasive species largely conserve their climatic niche.

The ecological niche is a key concept for elucidating patterns of species distributions and developing strategies for conserving biodiversity. However, recent times are seeing a widespread debate whether species niches are conserved across space and time (niche conservatism hypothesis). Biological invasions represent a unique opportunity to test this hypothesis in a short time frame at the global scale. We synthesized empirical findings for 434 invasive species from 86 studies to assess whether invasive species conserve their climatic niche between native and introduced ranges. Although the niche conservatism hypothesis was rejected in most studies, highly contrasting conclusions for the same species between and within studies suggest that the dichotomous conclusions of these studies were sensitive to techniques, assessment criteria, or author preferences. We performed a consistent quantitative analysis of the dynamics between native and introduced climatic niches reported by previous studies. Our results show there is very limited niche expansion between native and introduced ranges, and introduced niches occupy a position similar to native niches in the environmental space. These findings support the niche conservatism hypothesis overall. In particular, introduced niches were narrower for terrestrial animals, species introduced more recently, or species with more native occurrences. Niche similarity was lower for aquatic species, species introduced only intentionally or more recently, or species with fewer introduced occurrences. Climatic niche conservatism for invasive species not only increases our confidence in transferring ecological niche models to new ranges but also supports the use of niche models for forecasting species responses to changing climates.

Species distribution models have limited spatial transferability for invasive species.

The reliability of transferring species distribution models (SDMs) to new ranges and future climates has been widely debated. Biological invasions offer the unique opportunity to evaluate model transferability, as distribution data between species' native and introduced ranges are geographically independent of each other. Here, we performed the first global quantitative synthesis of the spatial transferability of SDMs for 235 invasive species and assessed the association of model transferability with the focal invader, model choice and parameterisation. We found that SDMs had limited spatial transferability overall. However, model transferability was higher for terrestrial endotherms, species introduced from or to the Southern Hemisphere, and species introduced more recently. Model transferability was also positively associated with the number of presences for model calibration and evaluation, respectively, but negatively with the number of predictors. These findings highlight the importance of considering the characteristics of the focal invader, environment and modelling in the application and assessment of SDMs.

Fish species sensitivity classification for environmental impact assessment, conservation and restoration planning.

Species conservation, river rehabilitation, stock enhancement, environmental impact assessment and related planning tools require indicators to identify significant impacts but also mitigation success. Since river systems are shaped by disturbances from floods and droughts, typical riverine fish species should have evolved life history traits providing resilience against such disturbances. This study compiled and analyzed resilience traits of European lampreys and fish species to derive a novel sensitivity classification of species to mortality. We assembled life history traits like maximum length, migration type, mortality, fecundity, age at maturity, and generation time of 168 species and created a novel method to weigh and integrate all traits to generate a final sensitivity score from one (low sensitivity) to three (high sensitivity) for each species. Large-bodied, diadromous, rheophilic and lithophilic species such as sturgeons, sea trout, and Atlantic salmon usually appeared to have high sensitivity to additional adult fish mortality, whereas small-bodied, limnophilic and phytophilic species with fast generation cycles were of low sensitivity. The final scoring and classification of 168 European lampreys and fish species according to their sensitivity can be easily regionalized by selecting the most sensitive candidates according to the local species pool. This sensitivity classification has major implications for advancing impact assessment, allowing better targeting of species for conservation measures, benchmarking progress during rehabilitation and enhancing the objective evaluation of the success of restoration projects.

Effect of recreational-fisheries management on fish biodiversity in gravel pit lakes, with contrasts to unmanaged lakes.

Gravel pit lakes are novel ecosystems that can be colonized by fish through natural or anthropogenic pathways. In central Europe, many of them are managed by recreational anglers and thus experience regular fish stocking. However, also unmanaged gravel pits may be affected by stocking, either through illegal fish introductions or, occasionally, by immigration from connected water bodies. We sampled 23 small (< 20 ha) gravel pit lakes (16 managed and 7 unmanaged) in north-western Germany using littoral electrofishing and multimesh gillnets. Our objective was to compare the fish biodiversity in gravel pit lakes in the presence or absence of recreational fisheries. Given the size of the sampled lakes, we expected species poor communities and elevated fish diversity in the managed systems due to regular stocking of game fish species. Our study lakes were primarily mesotrophic and did not differ in key abiotic and biotic environmental characteristics. Lakes of both management types hosted similar fish abundances and biomasses, but were substantially different in terms of fish community structure and species richness. Fish were present in all lakes, with a minimum of three species. Higher α-diversity and lower ß-diversity was discovered in managed gravel pit lakes compared to unmanaged lakes. Consequently, recreational-fisheries management fostered homogenization of fish communities, by stocking a similar set of fish species desired by anglers such as piscivorous fish and large bodied cyprinids. However, unmanaged gravel pit lakes were also affected by human-mediated colonization, presumably by illegal fish releases. Hardly any non-native species were detected, suggesting that recreational-fisheries management did not foster the spread of exotic species in our study region.

The effects of recreational and commercial navigation on fish assemblages in large rivers.

Recreational and commercial navigation is omnipresent, rendering European large rivers highways for cargo vessels, passenger ships and sport boats. Any types of motorized vessels create waves and drawdown eroding shallow shore areas. Consequently, inland navigation alters the living environment of fish with specific habitat requirements on nursing, hatching and spawning along shorelines. We assess the influence of recreational (sport boats) and commercial navigation (passenger ships, cargo vessels) on fish assemblages. Seven fish population metrics (FPM) were analyzed for 396 fish samplings at 88 sites in six large rivers characterized by seven different estimates of navigation intensity to identify FPM sensitive to inland navigation. Navigation intensity was characterized by frequency, total freight transported, total carrying capacity, degree of capacity utilization and by numbers of empty running vessels, aiming to approximate whether frequency, freight or draft of cargo vessels matter most. Densities of lithophilic fish were most sensitive to frequencies of sport boats, passenger ships and cargo vessels and declined as navigation traffic increased. Densities of rheophilic fish declined likewise but were less sensitive than lithophils. Frequency, freight and carrying capacity of cargo vessels had comparable effects on FPM and are equally useful in addition to frequency of sport boats and passenger ships to assess the impacts of recreational and commercial navigation on fish assemblages. Lower species richness indicated a specific influence of vessel draft on fish diversity. Our study shows that both recreational and commercial navigation impair fish assemblages in navigable rivers. Operation-related navigation impacts act on top of river regulation and engineering works to maintain fairways in the main channel. Therefore, impacts from recreational and commercial navigation must be especially addressed in addition to mitigating impacts from river regulation and hydromorphological degradation to achieve environmental objectives such as species conservation, ecological improvements and river rehabilitation.

Disentangling multiple pressures on fish assemblages in large rivers.

European large rivers are exposed to multiple human pressures and maintained as waterways for inland navigation. However, little is known on the dominance and interactions of multiple pressures in large rivers and in particular inland navigation has been ignored in multi-pressure analyzes so far. We determined the response of ten fish population metrics (FPM, related to densities of diagnostic guilds and biodiversity) to 11 prevailing pressures including navigation intensity at 76 sites in eight European large rivers. Thereby, we aimed to derive indicative FPM for the most influential pressures that can serve for fish-based assessments. Pressures' influences, impacts and interactions were determined for each FPM using bootstrapped regression tree models. Increased flow velocity, navigation intensity and the loss of floodplains had the highest influences on guild densities and biodiversity. Interactions between navigation intensity and loss of floodplains and between navigation intensity and increased flow velocity were most frequent, each affecting 80% of the FPM. Further, increased sedimentation, channelization, organic siltation, the presence of artificial embankments and the presence of barriers had strong influences on at least one FPM. Thereby, each FPM was influenced by up to five pressures. However, some diagnostic FPM could be derived: Species richness, Shannon and Simpson Indices, the Fish Region Index and lithophilic and psammophilic guilds specifically indicate rhithralisation of the potamal region of large rivers. Lithophilic, phytophilic and psammophilic guilds indicate disturbance of shoreline habitats through both (i) wave action induced by passing vessels and (ii) hydromorphological degradation of the river channel that comes along with inland navigation. In European large rivers, inland navigation constitutes a highly influential pressure that adds on top of the prevailing hydromorphological degradation. Therefore, river management has to consider river hydromorphology and inland navigation to efficiently rehabilitate the potamal region of large rives.

Improved river continuity facilitates fishes' abilities to track future environmental changes.

Barriers represent one of the largest anthropogenic impacts on the ecological status of rivers, and they also potentially restrict fishes' ability to respond to future environmental changes. Thus, river management aims to restore the longitudinal connectivity of rivers to allow continuous migration and movement of water, sediments and biota. However, it is often unclear whether the targeted barriers are also those most relevant for fish species, particularly to track future habitat shifts caused by environmental change. In this study, we applied species distribution models and the GIS-based fish dispersal model FIDIMO to evaluate the impacts of barriers (e.g. weirs and dams) on the dispersal of 17 native fish species in the European River Elbe with a particular focus on climate- and land use-induced habitat shifts. Specifically, we compared three scenarios of longitudinal connectivity: (i) current longitudinal connectivity, (ii) connectivity improvements as planned by river managers for 2021 and (iii) a reference with full longitudinal connectivity. The models indicated that barriers restricted the movement of two modeled fish species on average, thus impeding fishes' abilities to track future habitat shifts. Moreover, the number of species affected by barriers increased downstream. For the River Elbe, our results suggest that river management has most likely identified the most relevant barriers in respect to the modeled species and future environmental change. We emphasize that river management and barrier prioritization must thoroughly consider species-specific movement and dispersal abilities, as well as the specific spatial arrangement of barriers in the river system in relation to the spatial distribution of species' populations and suitable habitats.

Diverse Approaches to Implement and Monitor River Restoration: A Comparative Perspective in France and Germany.

River restoration is a main emphasis of river management in European countries. Cross-national comparisons of its implementation are still rare in scientific literature. Based on French and German national censuses, this study compares river restoration practices and monitoring by analysing 102 French and 270 German projects. This comparison aims to draw a spatial and temporal framework of restoration practices in both countries to identify potential drivers of cross-national similarities and differences. The results underline four major trends: (1) a lag of almost 15 years in river restoration implementation between France and Germany, with a consequently higher share of projects in Germany than in France, (2) substantial similarities in restored reach characteristics, short reach length, small rivers, and in "agricultural" areas, (3) good correspondences between stressors identified and restoration measures implemented. Morphological alterations were the most important highlighted stressors. River morphology enhancement, especially instream enhancements, were the most frequently implemented restoration measures. Some differences exist in specific restoration practices, as river continuity restoration were most frequently implemented in French projects, while large wood introduction or channel re-braiding were most frequently implemented in German projects, and (4) some quantitative and qualitative differences in monitoring practices and a significant lack of project monitoring, especially in Germany compared to France. These similarities and differences between Germany and France in restoration application and monitoring possibly result from a complex set of drivers that might be difficult to untangle (e.g., environmental, technical, political, cultural).

The future distribution of river fish: The complex interplay of climate and land use changes, species dispersal and movement barriers.

The future distribution of river fishes will be jointly affected by climate and land use changes forcing species to move in space. However, little is known whether fish species will be able to keep pace with predicted climate and land use-driven habitat shifts, in particular in fragmented river networks. In this study, we coupled species distribution models (stepwise boosted regression trees) of 17 fish species with species-specific models of their dispersal (fish dispersal model FIDIMO) in the European River Elbe catchment. We quantified (i) the extent and direction (up- vs. downstream) of predicted habitat shifts under coupled "moderate" and "severe" climate and land use change scenarios for 2050, and (ii) the dispersal abilities of fishes to track predicted habitat shifts while explicitly considering movement barriers (e.g., weirs, dams). Our results revealed median net losses of suitable habitats of 24 and 94 river kilometers per species for the moderate and severe future scenarios, respectively. Predicted habitat gains and losses and the direction of habitat shifts were highly variable among species. Habitat gains were negatively related to fish body size, i.e., suitable habitats were projected to expand for smaller-bodied fishes and to contract for larger-bodied fishes. Moreover, habitats of lowland fish species were predicted to shift downstream, whereas those of headwater species showed upstream shifts. The dispersal model indicated that suitable habitats are likely to shift faster than species might disperse. In particular, smaller-bodied fish (<200 mm) seem most vulnerable and least able to track future environmental change as their habitat shifted most and they are typically weaker dispersers. Furthermore, fishes and particularly larger-bodied species might substantially be restricted by movement barriers to respond to predicted climate and land use changes, while smaller-bodied species are rather restricted by their specific dispersal ability.

Effects of macrophyte development on the oxygen metabolism of an urban river rehabilitation structure.

To compensate for fairway enlargements and the hydraulic impacts of navigation activity, an artificial rehabilitation structure was constructed in the urban, navigable River Spree in 2004. This wave-protected, shallow littoral zone proved to be highly effective in reducing vessel-induced waves and provided suitable conditions for the development of aquatic plants. However, in time it became less suitable for other aquatic organisms due to hypoxic conditions in late summer. This study aimed to comparatively calculate and analyze the oxygen balance of the rehabilitation structure and the main channel five years after the construction in 2009. In the rehabilitation structure, the production to respiration ratio ranged between 0.10 and 0.34 at the peak of vegetation density, while in the main channel in front of the rehabilitation structure it ranged between 0.67 and 0.86. Dense vegetation limited the water exchange and caused oxygen depletion. Thus, atmospheric oxygen input through the water surface and due to long-term water level changes became the most important supply processes for oxygen in the rehabilitation structure. Enhancing the oxygen supply to improve the suitability of the rehabilitation structure for other aquatic taxa requires an increase in water exchange with the main channel, e.g. by adaptively increasing the lateral connectivity.

Coupling systematic planning and expert judgement enhances the efficiency of river restoration.

Ineffectiveness of current river restoration practices hinders the achievement of ecological quality targets set by country-specific regulations. Recent advances in river restoration help planning efforts more systematically to reach ecological targets at the least costs. However, such approaches are often desktop-based and overlook real-world constraints. We argue that combining two techniques commonly used in the conservation arena - expert judgement and systematic planning - will deliver cost-effective restoration plans with a high potential for implementation. We tested this idea targeting the restoration of spawning habitat, i.e. gravel bars, for 11 rheophilic fish species along a river system in Germany (Havel-Spree rivers). With a group of local fish experts, we identified the location and extent of potential gravel bars along the rivers and necessary improvements to migration barriers to ensure fish passage. Restoration cost of each gravel bar included the cost of the action itself plus a fraction of the cost necessary to ensure longitudinal connectivity by upgrading or building fish passages located downstream. We set restoration targets according to the EU Water Framework Directive, i.e. relative abundance of 11 fish species in the reference community and optimised a restoration plan by prioritising a subset of restoration sites from the full set of identified sites, using the conservation planning software Marxan. Out of the 66 potential gravel bars, 36 sites which were mainly located in the downstream section of the system were selected, reflecting their cost-effectiveness given that fewer barriers needed intervention. Due to the limited overall number of sites that experts identified as being suitable for restoring spawning habitat, reaching abundance-targets was challenged. We conclude that coupling systematic river restoration planning with expert judgement produces optimised restoration plans that account for on-the-ground implementation constraints. If applied, this approach has a high potential to enhance overall efficiency of future restoration efforts.

Synergistic and antagonistic interactions of future land use and climate change on river fish assemblages.

River ecosystems are threatened by future changes in land use and climatic conditions. However, little is known of the influence of interactions of these two dominant global drivers of change on ecosystems. Does the interaction amplify (synergistic interaction) or buffer (antagonistic interaction) the impacts and does their interaction effect differ in magnitude, direction and spatial extent compared to single independent pressures. In this study, we model the impact of single and interacting effects of land use and climate change on the spatial distribution of 33 fish species in the Elbe River. The varying effects were modeled using step-wise boosted regression trees based on 250 m raster grid cells. Species-specific models were built for both 'moderate' and 'extreme' future land use and climate change scenarios to assess synergistic, additive and antagonistic interaction effects on species losses, species gains and diversity indices and to quantify their spatial distribution within the Elbe River network. Our results revealed species richness is predicted to increase by 0.7-2.9 species by 2050 across the entire river network. Changes in species richness are likely to be spatially variable with significant changes predicted for 56-85% of the river network. Antagonistic interactions would dominate species losses and gains in up to 75% of the river network. In contrast, synergistic and additive effects would occur in only 20% and 16% of the river network, respectively. The magnitude of the interaction was negatively correlated with the magnitudes of the single independent effects of land use and climate change. Evidence is provided to show that future land use and climate change effects are highly interactive resulting in species range shifts that would be spatially variable in size and characteristic. These findings emphasize the importance of adaptive river management and the design of spatially connected conservation areas to compensate for these high species turnovers and range shifts.