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Riparian ecosystems in the 21st century are likely to play a critical role in determining the vulnerability of natural and human systems to climate change, and in influencing the capacity of these systems to adapt. Some authors have suggested that riparian ecosystems are particularly vulnerable to climate change impacts due to their high levels of exposure and sensitivity to climatic stimuli, and their history of degradation. Others have highlighted the probable resilience of riparian ecosystems to climate change as a result of their evolution under high levels of climatic and environmental variability. We synthesize current knowledge of the vulnerability of riparian ecosystems to climate change by assessing the potential exposure, sensitivity, and adaptive capacity of their key components and processes, as well as ecosystem functions, goods and services, to projected global climatic changes. We review key pathways for ecological and human adaptation for the maintenance, restoration and enhancement of riparian ecosystem functions, goods and services and present emerging principles for planned adaptation. Our synthesis suggests that, in the absence of adaptation, riparian ecosystems are likely to be highly vulnerable to climate change impacts. However, given the critical role of riparian ecosystem functions in landscapes, as well as the strong links between riparian ecosystems and human well-being, considerable means, motives and opportunities for strategically planned adaptation to climate change also exist. The need for planned adaptation of and for riparian ecosystems is likely to be strengthened as the importance of many riparian ecosystem functions, goods and services will grow under a changing climate. Consequently, riparian ecosystems are likely to become adaptation 'hotspots' as the century unfolds.

ABSTRACT Identifying the most important variables that determine patterns and processes is one of the main goals in many scientific fields, including ecological and evolutionary studies. Variable or relative importance is generally seen as the proportion of the variation in a response variable explained directly and indirectly by a specific predictor. Although partial regression coefficients are perhaps the most frequently used, ‘standard’, statistical technique in ecological and evolutionary studies, they are inadequate indices of variable importance when predictors are intercorrelated, which tends to be the rule in most observational data sets. Among other statistical techniques, random forests and hierarchical partitioning are designed to cope with collinearity but are still much less used than beta weights to measure variable importance. Here, we compared random forests and hierarchical partitioning with linear mixed models to attempt to unravel the individual and shared variation of environmental, economic, and human population factors with success of alien species richness in eight taxonomic groups at a global scale. Results showed that random forests and hierarchical partitioning generally agreed in ranking variable importance but showed considerably different conclusions to the standard statistical approach. Specifically, random forests and hierarchical partitioning attached more importance to economic and human population variables in explaining spatial patterns of alien species richness than did region area and mean air temperature, which were emphasized more by the standard approach. Beta weights also tended to highlight less correlated predictors, such as sampling effort and precipitation. Variable importance in random forests attached more importance to economic than population variables and to absolute rather than relative predictors. In conclusion, using variable importance measures enable to better identify the most significant drivers of biological invasions but it can also be applied to other biological and scientific questions, leading to tackle more efficient management and conservation decisions in global change research. The current paper compares several statistical techniques to estimate the variable importance of the main drivers shaping the global distribution of alien species richness in eight taxonomic groups. Variable importance measures can be applied to address other biodiversity questions, particularly those arising from the impacts of global change.

1. Agricultural expansion and intensification are major threats to tropical biodiversity. In addition to the direct removal of native vegetation, agricultural expansion often elicits other human-induced disturbances, many of which are poorly addressed by existing environmental legislation and conservation programmes. This is particularly true for tropical freshwater systems, where there is considerable uncertainty about whether a legislative focus on protecting riparian vegetation is sufficient to conserve stream fauna. 2. To assess the extent to which stream fish are being effectively conserved in agricultural landscapes, we examined the spatial distribution of assemblages in river basins to identify the relative importance of human impacts at instream, riparian and catchment scales, in shaping observed patterns. We used an extensive dataset on the ecological condition of 83 low-order streams distributed in three river basins in the eastern Brazilian Amazon. 3. We collected and identified 24,420 individual fish from 134 species. Multiplicative diversity partitioning revealed high levels of compositional dissimilarity (DS) among stream sites (DS = 0.74 to 0.83) and river basins (DS = 0.82), due mainly to turnover (77.8% to 81.8%) rather than nestedness. The highly heterogeneous fish faunas in small Amazonian streams underscore the vital importance of enacting measures to protect forests on private lands outside of public protected areas. 4. Instream habitat features explained more variability in fish assemblages (15%-19%) than riparian (2%-12%), catchment (4%-13%) or natural covariates (4%-11%). Although grouping species into functional guilds allowed us to explain up to 31% of their abundance (i.e. for nektonic herbivores), individual riparian - and catchment - scale predictor variables that are commonly a focus of environmental legislation explained very little of the observed variation (partial R² values mostly <5%). 5. Policy implications. Current rates of agricultural intensification and mechanization tropical landscapes are unprecedented, yet the existing legislative frameworks focusing on protecting riparian vegetation seem insufficient to conserve stream environments and their fish assemblages. To safeguard the species-rich freshwater biota of small Amazonian streams, conservation actions must shift towards managing whole basins and drainage networks, as well as agricultural practices in already-cleared land.

Loss of functional connectivity following habitat loss and fragmentation could drive species declines. A comprehensive understanding of fragmentation effects on functional connectivity of an ecological assemblage requires investigation of multiple species with different mobilities, at different spatial scales, for each sex, and in different landscapes. Based on published data on mobility and ecological responses to fragmentation of 10 woodland-dependent birds, and using simulation studies, we predicted that (1) fragmentation would impede dispersal and gene flow of eight \"decliners\" (species that disappear from suitable patches when landscape-level tree cover falls below species-specific thresholds), but not of two \"tolerant\" species (whose occurrence in suitable habitat patches is independent of landscape tree cover); and that fragmentation effects would be stronger (2) in the least mobile species, (3) in the more philopatric sex, and (4) in the more fragmented region. We tested these predictions by evaluating spatially explicit isolation-by-landscape-resistance models of gene flow in fragmented landscapes across a 50 × 170 km study area in central Victoria, Australia, using individual and population genetic distances. To account for sex-biased dispersal and potential scale- and configuration-specific effects, we fitted models specific to sex and geographic zones. As predicted, four of the least mobile decliners showed evidence of reduced genetic connectivity. The responses were strongly sex specific, but in opposite directions in the two most sedentary species. Both tolerant species and (unexpectedly) four of the more mobile decliners showed no reduction in gene flow. This is unlikely to be due to time lags because more mobile species develop genetic signatures of fragmentation faster than do less mobile ones. Weaker genetic effects were observed in the geographic zone with more aggregated vegetation, consistent with gene flow being unimpeded by landscape structure. Our results indicate that for all but the most sedentary species in our system, the movement of the more dispersive sex (females in most cases) maintains overall genetic connectivity across fragmented landscapes in the study area, despite some small-scale effects on the more philopatric sex for some species. Nevertheless, to improve population viability for the less mobile bird species, structural landscape connectivity must be increased.

Summary Nutrient (N and P) loading may affect functioning in aquatic ecosystems by restructuring producer assemblages with flow‐on effects to consumers. Trophic niche occupancy and trophic organization of consumers are key components of ecosystem function that have been increasingly investigated using quantitative isotopic niche indices. These indices are based on the premise that the isotopic values of consumer tissues indicate their assimilated diet. Typically, isotopic niche indices are calculated using only consumer isotope data, which limit their application for spatial and temporal comparisons because consumer isotopic niches depend on isotopic variability of available autotrophs. We used measures of isotopic variability of autotrophs to standardize isotopic niche indices, which enabled us to compare trophic organization of fish assemblages in nine estuaries spanning a broad range of nutrient loading. We related standardized isotopic niche indices of fish assemblages to nitrogen and phosphorous loads and hydrological flushing of the estuaries in autumn and spring. The estuarine fish assemblages studied here showed greater trophic diversity and less redundancy given moderate to high inorganic nitrogen loading. Taxonomic richness partly influenced three isotopic niche indices measuring trophic diversity, but not measures of redundancy. Similar patterns may occur in other systems in which nitrogen loads have increased but the diversity of primary producers has not been reduced to a single dominant source. Our results demonstrate bottom‐up controls of estuarine food webs. Effects of inorganic nitrogen loading were transmitted upwards through the food web to affect the trophic organization of higher trophic levels, demonstrating the crucial role of nitrogen for estuarine trophic dynamics. Lay Summary

Whatever the business model, Diversity and Distributions has become a lead journal in the field thanks to the free‐of‐charge support of the scientific community as editors and reviewers and has long been a zero‐cost publishing outlet. [...]presumably, substantial room exists to reduce profit margins and increase participation for a journal in a field like that of Diversity and Distributions. Some platinum open access journals have close relationships with scientific societies or charitable foundations, are subsidized by a particular institution or entity, or charge much more modest APCs in exchange for membership dues; examples of journals using these different funding solutions include Perspectives in Ecology and Conservation, Current Science, Current Zoology, Emerging Infectious Diseases, European Journal of Ecology, Neotropical Biodiversity, and Revista Mexicana de Biodiversidad.

Waterbird population and species diversity maintenance are important outcomes of wetland conservation management, but knowledge gaps regarding waterbird movements affect our ability to understand and predict waterbird responses to management at appropriate scales. Movement tracking using satellite telemetry is now allowing us to fill these knowledge gaps for highly mobile waterbirds at continental scales, including in remote areas for which data have been historically difficult to acquire. We used GPS satellite telemetry to track the movements of 122 individuals of three species of ibis and spoonbills ( Threskiornithidae ) in Australia from 2016 to 2023. We analysed movement distances, residency periods and areas, and foraging-site fidelity. From this we derived implications for water and wetland management for waterbird conservation. This is the first multi-year movement tracking data for ibis and spoonbills in Australia, with some individuals tracked continuously for more than five years including from natal site to first breeding attempt. Tracking revealed both inter- and intra-specific variability in movement strategies, including residency, nomadism, and migration, with individuals switching between these behaviours. During periods of residency, areas used and distances travelled to forage were highly variable and differed significantly between species. Sixty-five percent of identified residency areas were not associated with wetlands formally listed nationally or internationally as important. Tracking the movements of waterbirds provides context for coordinated allocation of management resources, such as provision of environmental water at appropriate places and times for maximum conservation benefit. This study highlights the geographic scales over which these birds function and shows how variable waterbird movements are. This illustrates the need to consider the full life cycle of these birds when making management decisions and evaluating management impacts. Increased knowledge of the spatio-temporal interactions of waterbirds with their resource needs over complete life cycles will continue to be essential for informing management aimed at increasing waterbird numbers and maintaining long-term diversity.

Fragmentation of natural landscapes is a pervasive process in the world. Common models predict coherent change in assemblages, with less numerous species becoming locally extinct first, then species of intermediate abundance, and so forth. Relative‐abundance distributions should change systematically in landscapes characterized by greater change. Such a predictable sequence of change is not evident in the avifaunas of landscapes of central Victoria, Australia, where relative‐abundance patterns in more affected landscapes bear little resemblance to reference distributions. I provide two sets of analyses of relative‐abundance distributions: (1) analyses that do not depend on the identity of individual species and (2) abundance spectra, which use ordered lists of species ranked by species’ commonness in reference systems. While abundance spectra change dramatically in smaller remnants, relative‐abundance distributions change little, suggesting that the “reorganization” of abundances occurs over ecological time frames. The dispersal‐limited multinomial is a flexible distribution that may fit many data sets yet be unrelated to assumptions (species neutrality) and processes (fixed total numbers of individuals) of the unified neutral theory. A more complete understanding of human impacts at landscape scales must include capacities to predict those species that will be advantaged by change, as well as those that will be disadvantaged.

Aim We assessed the resistance and resilience of anuran amphibians to an abrupt change in weather conditions in 2010–12 (the 'Big Wet') following the most pronounced drought in eastern Australia's records (1997–2010, the 'Big Dry'). Location Five pairs of landscapes (each of 19.6 km 2 ) spread across 30,000 km 2 in temperate, inland Australia. One in each pair was eucalypt woodland while the other was cleared agricultural land; there were eight representative waterbodies in each landscape. Methods We collected data on anuran abundances, species richness and breeding by using aural surveys and visual searches. We surveyed six times during the austral winter–springs of 2006 and 2007 (the Big Dry) and six times in the corresponding seasons of 2011 and 2012 (the Big Wet); our results refer only to species breeding in the winter–spring season. Results Mean species richness, total numbers of calling males and numbers of the five most common species of anurans increased in the Big Wet compared with the Big Dry, but the least common species did not. Proportions of waterbodies with eggs or tadpoles increased in the Big Wet, but the occurrence of eggs and tadpoles was still low (evidence of presence in < 50% of waterbodies). The most common species had relatively high resistance to the first 5 years of the Big Dry, but all declined sharply after a decade of drought. Four of the common species showed some resilience, but reporting rates fell much below the peak values prior to the Big Dry. There were virtually no records for seven other species that had been recorded previously in the region. Main conclusions The pressure of drying, warming climates, even when broken by shorter wet periods, seems to be sufficient to induce regional-scale declines even among species that, from global analyses of risk factors, might be expected to be relatively immune from such effects.