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Habitat loss has major impacts on biodiversity. Yet, such impacts are not always linear, as there can be threshold values of habitat amount below which species become extirpated from human-modified landscapes (extinction thresholds). This may be particularly the case for species with high habitat spatial requirements, especially in regions with a long land-use history, which have a lower extinction debt. To address these issues, we evaluated the linear and non-linear effects of landscape-scale forest (habitat) loss on primate species richness in regions with relatively new (Amazon) and old (Atlantic Forest) histories of land-use change. We also evaluated the role of mean home range size in regulating species responses to forest loss. Extinction thresholds were higher in the Atlantic Forest (78% remaining forest cover) than in the Amazon (45%), but primate-landscape associations were stronger in the Amazon. Thus, despite its recent land-use history, Amazon primates are more sensitive to habitat loss. As predicted, mean home range size decreased with forest loss in both biomes. Our findings highlight the importance of stopping deforestation in both biomes to maintain habitat amount above these thresholds. Yet, as

Conservation actions such as habitat protection, restoration, and translocations are critical actions in preventing further extinctions of threatened species. We used the 152 threatened species on the International Union for the Conservation of Nature's Red List with conservation translocations as a recommended conservation action to access the habitat quality of these species' ranges. We determined where multi-species conservation translocation and forest restoration efforts can be concentrated. To determine the habitat quality of species' ranges, we assessed forest cover, forest restoration potential, protected area status, and invasive species concerns. Forty-four percent (67 species) of species with translocations recommended have part of their range in a protected area, existing forest cover, and currently no invasive species risk. However, the majority (85 species) currently need habitat management (63 species), invasive species control (71 species), or protection (34 species). We also identified key differences between species recommended for reintroductions (115 species) and benign introductions (37 species), such as the percentage of a species' range within a protected area, in which reintroductions (median = 7.4%) had more than benign introductions (median = 0.9%). Mauritius, central Africa, eastern Australia and Himalaya regions each have areas with range overlap of three or more species recommended for translocations and forest restoration potential. For those species with CT programs in place, mean forest cover was 32% and restoration potential was 16%, suggesting potential minimum habitat requirements for initial releases. Results provide a global perspective on reintroduction and translocation needs of threatened species with evidenced-based information on habitat quality, i.e. forest restoration potential, forest cover, protected areas, and invasive species control, to aid conservation translocation scientists and ultimately improve the success of such projects. [ABSTRACT FROM AUTHOR]

Predicting potential habitat across a landscape for rare species is extremely challenging. However, partitioned Mahalanobis D² methods avoid pitfalls commonly encountered when surveying rare species by using data collected only at known species locations. Minimum habitat requirements are then determined by examining a principal components analysis to find consistent habitat characteristics across known locations. We used partitioned D² methods to examine minimum habitat requirements of Indiana bats (Myotis sodalis) in the Champlain Valley of Vermont and New York, USA, across 7 spatial scales and map potential habitat for the species throughout the same area. We radiotracked 24 female Indiana bats to their roost trees and across their nighttime foraging areas to collect habitat characteristics at 7 spatial scales: 1) roost trees, 2) 0.1-ha circular plots surrounding the roost trees, 3) home ranges, and 4-7) 0.5-km, 1-km, 2-km, and 3-km buffers surrounding the roost tree. Roost trees (n = 50) typically were tall, dead, large-diameter trees with exfoliating bark, located at low elevations and close to water. Trees surrounding roosts typically were smaller in diameter and shorter in height, but they had greater soundness than the roost trees. We documented 14 home ranges in areas of diverse, patchy land cover types that were close to water with east-facing aspects. Across all landscape extents, area of forest within roost-tree buffers and the aspect across those buffers were the most consistent features. Predictive maps indicated that suitable habitat ranged from 4.7-8.1% of the area examined within the Champlain Valley. These habitat models further understanding of Indiana bat summer habitat by indicating minimum habitat characteristics at multiple scales and can be used to aid management decisions by highlighting potential habitat. Nonetheless, information on juvenile production and recruitment is lacking; therefore, assessments of Indiana bat habitat quality in the region are still incomplete. [ABSTRACT FROM AUTHOR]

Urbanization and urban sprawl generally degrade and diminish wildlife habitat, threatening to extirpate local populations. However, certain synanthropic species (e.g., coyotes, white‐tailed deer, and squirrels) are able to persist in urban environments and may even occur at greater densities than they do in their natural habitats. Eastern fox squirrels (Sciurus niger) are large tree squirrels that are known to be present in greater densities within urban areas. To determine how landscape characteristics may affect fox squirrel presence, we conducted line‐transect surveys along sidewalks on the Texas A&M University—College Station campus to record presence of fox squirrels and nearest tree species. We calculated Jacobs' index of selectivity (D) for use of trees by fox squirrels along the transects. Squirrel density was calculated for all transects and modeled using linear regression with environmental (e.g., tree density) and survey (e.g., transect distance) variables. Fox squirrels preferred only a small number of the available tree species, primarily Quercus and Ulmus species. Observed fox squirrel density significantly increased with time of day, temperature, density of oaks (Quercus spp.), and density of all trees, and decreased with distance and area of the transect. These results suggest that even when urban areas contain suitable habitat, use of urban environments by wildlife is still highly selective and dependent on specific habitat requirements. [ABSTRACT FROM AUTHOR]

Translocations, a conservation tool used to conserve and restore dwindling species, are often associated with high failure rates. Inadequate long‐term monitoring of both populations and their introduction sites beyond the initial years post‐translocation creates a gap in our understanding of the factors that determine translocation success or failure, resulting in less informed projects in the future. This lack of long‐term monitoring is partly caused by the absence of a well‐defined framework by which the success of the translocation can be measured, leading to premature and sometimes inaccurate assessments of their outcome. We investigated the long‐term outcome of a red squirrel translocation in the west of Ireland, specifically assessing the habitat changes in the translocation site since the introduction in 2005, and their impact on the capacity of the forest to sustain a population of a given size. Using digitised historical map data, we showed that the translocation site experienced a 53% reduction in suitable habitat. Additionally, there was a 41%–81% reduction in the total number of red squirrels the forest could support, according to feeding survey data. Clear‐felling, a forest fire and a shift in tree species composition collectively contributed to this decline in site suitability. This investigation underscores the complexity of translocation projects and emphasises the pivotal role of habitat quality in their outcomes. We advocate for detailed habitat assessments during the planning phase, avoidance of unstable habitats as translocation sites, and the implementation of long‐term monitoring practices. Translocations often face high failure rates, due in part to our lack of understanding of their long‐term outcomes. We investigated long‐term outcome of a red squirrel translocation in the west of Ireland, focusing on habitat loss and changes in carrying capacity. We found a 53% reduction in suitable habitat and a 41%–81% decline in carrying capacity, emphasising the importance of detailed habitat assessments and the use of stable sites for successful translocations. [ABSTRACT FROM AUTHOR]

Human‐mediated species introductions are contributing to the biotic homogenization of global flora and fauna. Despite extensive research, we lack simple methods of predicting how and where an introduced species will spread and establish, particularly in species with complex life histories in aquatic ecosystems. We predict that spread can be modeled simply using the characteristics of the invading population, specifically species growth rate and dispersal capacity. In addition, we predict that the establishment of introduced species should be explained by the characteristics of the receiving ecosystem. Using the brown trout (Salmo trutta) invasion on the Island of Newfoundland as a case study, we fit and test a reaction–diffusion model with brown trout population data collected from the literature. Next, we use statistical models to assess the influence of a suite of abiotic (conductivity, pH, turbidity, calcium), biotic (Atlantic salmon occurrence), and landscape (watershed relief, watershed area, distance to original introduction) variables on brown trout establishment (i.e., presence–absence) patterns. We find that observed coastal spread in Newfoundland is slow (~4.4 km/year), and that it lies on the lower end of the range of predictions made by the reaction–diffusion model parameterized based on the estimates of growth rate and movement from the literature (predicted spread range 1.4 to 92 km/year). Also, we did not find evidence for a relationship between abiotic or biotic variables and brown trout establishment. However, we did observe that landscape variables of the distance to trout introduction point and estuary area may explain establishment patterns along the south coast of Newfoundland. Our results suggest the importance of using population‐specific parameterization and the need to integrate regional landscape factors that are generally applicable across biological invasions (e.g., distance to introduction), and those that are more specific to the ecology of the invader (e.g., estuary area). Our study contextualizes the mechanisms that contribute to a slow invasion by an aquatic species with a complex life history and reveals that future studies need to integrate a variety of methods to elucidate the processes governing invasions. [ABSTRACT FROM AUTHOR]

Habitat conservation, particularly for large, multiple use areas, must account for the needs of multiple species. However, an unresolved issue is how to manage habitat when the needs of resident species conflict and when the habitat can only be modelled at a coarse scale. Here, we illustrate an approach to optimizing habitat management using an example of a community of forest-breeding birds. We used potential habitat maps for 20 bird species in northern Wisconsin and identified a spatial arrangement that maximizes conservation value for multiple species, maximizes connectivity and minimizes the area needed for conservation. To do this, we ranked each cell of the study area using a nested percentage value, with for example the highest-ranking 1% holding lands of highest conservation value. As we progressively increased the portion of landscape considered, starting with the highest-ranking habitat first, the number of species for which the minimum habitat requirements were met reached plateaux at 3% and 20% of the landscape. To provide enough area to meet the minimum habitat requirements for all but two species, an estimated 20% of the habitat with the highest conservation value, c. 1 million hectares, would need to be maintained. Of that 20% highest-ranking area, 42% was on public lands, compared with 28% for the study area. Tribal lands held a disproportionally large amount of area estimated to be of high conservation value: within the highest-ranking 1% of land, 14% consisted of tribal lands, while these lands held only 5% of the entire study area's forests. Synthesis and applications. Hierarchical prioritization provided an efficient mapping approach and the regional perspective necessary to identify management opportunities for a wide range of species. However, it could not explicitly address conflicts among species with overlapping potential habitat but incompatible fine-scale habitat needs. Ignoring this issue may lead to a failure to meet conservation objectives. This issue of habitat mischaracterization needs to be recognized in conservation planning objectives, preferably integrated in an optimization strategy, and can only be partly addressed with a post hoc, stepwise heuristic approach. [ABSTRACT FROM AUTHOR]

Aim: The rapidly changing Arctic is ideal for investigating uncertainties in climate projections. Despite the challenges of collecting data in this region, an unprecedented large‐scale survey of shorebirds has been conducted over the last 30 years. Our study aimed to (1) develop probabilistic estimates for the change in suitable habitat for 10 Arctic shorebird species in Canada by 2075 and (2) assess the contribution of modelling decisions to the uncertainty in these estimates. Location: Arctic Canada. Methods: To evaluate uncertainty, we considered six classes of modelling decisions, yielding 216 unique projections for each species. We tested three decisions that are less commonly explored − the pool of candidate variables, a method for selecting variables, and the maximum distance of tree line dispersal, as well as the modelling algorithm, carbon emissions scenario, and global circulation model. We used a bootstrapping approach, creating a probability distribution for the proportional change in suitable habitat for each species. Results: Our findings indicated a substantial risk for 8/10 species to lose over half of their suitable breeding habitat, but this projection is much less certain than has been described previously. While much uncertainty is unexplained, we were surprised that the largest source of uncertainty among our modelling decisions was from our choice of methods for variable selection, that the other modelling decisions were relatively small sources of uncertainty, overshadowing other modelling decisions. Main Conclusions: While most scenarios predict a northward shift and significant habitat loss for Arctic‐breeding shorebirds, the Arctic Archipelago of Canada will remain an important refuge because in many other Arctic regions, there is no land farther north for these species to shift into. A comprehensive understanding of uncertainty is important for deciding if future projections can or should be used when planning climate‐resilient protected area networks. [ABSTRACT FROM AUTHOR]

Fragmentation isolates individuals and restricts access to valuable habitat with severe consequences for populations, such as reduced gene flow, disruption of recolonization dynamics, reduced resiliency to disturbance, and changes in aquatic community structure. Translocations to mitigate the effects of fragmentation and habitat loss are common, but few are rigorously evaluated, particularly for fishes. Over six years, we translocated 1215 individuals of four species of imperiled fish isolated below a barrier on the San Juan River, Utah, USA, that restricts access to upstream habitat. We used re‐encounter data (both passive integrated transponder tag and telemetry detections and physical recaptures) collected between 2016 and 2023, to inform a spatially explicit multistate mark–recapture model that estimated survival and transition probabilities of translocated and non‐translocated individuals, both below and above the barrier. Individuals of all four species moved large (>200 km) distances upstream following translocation, with the maximum upstream encounter distance varying by species. Results from the multistate mark–recapture model suggested translocated fish survived at a higher rate compared with non‐translocated fish below the barrier for three of the four species. Above the barrier, translocated individuals survived at similar rates as non‐translocated fish for bluehead sucker (Catostomus discobolus) and flannelmouth sucker (Catostomus latipinnis), while survival rates of translocated endangered Colorado pikeminnow (Ptychocheilus lucius; mean, 95% CI: 0.75, 0.55–0.88) and endangered razorback sucker (Xyrauchen texanus; 0.86, 0.75–0.92) were higher relative to non‐translocated individuals (Colorado pikeminnow: 0.52, 0.51–0.54; razorback sucker: 0.75, 0.74–0.75). Transition probabilities from above the barrier to below the barrier were generally low for three of the four species (all upper 95% CI ≤ 0.23), but they were substantially higher for razorback sucker. Our results suggest translocation to mitigate fragmentation and habitat loss can have demographic benefits for large‐river fish species by allowing movements necessary to complete their life history in heterogeneous riverscapes. Further, given the costs or delays in providing engineered fish passage structures or in achieving dam removal, we suggest translocations may provide an alternative conservation strategy in fragmented river systems. [ABSTRACT FROM AUTHOR]

The Hamilton Harbour Remedial Action Plan has adopted a dissolved oxygen goal for restoring habitat in the pelagic portion of Hamilton Harbour based on the ecological needs of Cisco (Coregonus artedii), a fish formerly abundant in Hamilton Harbour. The goal for dissolved oxygen is based on retaining an adequate volume of optimum Cisco habitat characterized as temperature <20°C and dissolved oxygen >6 mg l−1during the June to September period. The goal also specifies minimum habitat requirements for when optimum conditions are not achieved, that being a smaller volume of refuge habitat with temperature <20°C and dissolved oxygen >3 mg l−1for no more than 2 weeks per year. Weekly temperature and dissolved oxygen profiles during May to October, 1987 to 2012 in the center of Hamilton Harbour were assessed to evaluate optimum and refuge Cisco habitat relative to the Remedial Action Plan goal for dissolved oxygen. This goal was met only in 2009. However, this was fortuitous, based on a combination of cooler water temperatures in May and June and exchanges of cool oxygenated water from Lake Ontario. From 1987 to 2002 optimum habitat was estimated to be absent at least one week and up to seven weeks during June to September. Cisco could not have survived in Hamilton Harbour during six of these years when refuge habitat was absent for one or two weeks. Since 2003, Cisco habitat in Hamilton Harbour improved markedly, as some refuge habitat was always present. As well, the number of weeks with inadequate refuge habitat, and with no optimum habitat has declined. These improvements in Cisco habitat since 2003 were related to higher dissolved oxygen in the mid-depths of Hamilton Harbour. [ABSTRACT FROM AUTHOR]

Collaborative approaches to conservation management are critical to respond to the ongoing biodiversity crisis. However, local community involvement in many conservation actions is lacking, especially within translocation and reintroduction programs. Similarly, rapid integration of genetic information into collaborative programs with local communities is rarely conducted. Here, we describe a community‐based and collaborative reintroduction program for a threatened Australian freshwater fish, the southern pygmy perch (Nannoperca australis). We integrate on‐the‐ground translocation efforts by volunteers from local communities, captive breeding by a private aquarium business, and genetic analyses done by a research institution to provide a holistic framework for the reintroduction of southern pygmy perch. We evaluated genetic diversity, population structure, relatedness, and inbreeding across the duration of the reintroduction program using data from neutral and adaptive genomic markers. This allowed us to assess the ability of such a program to minimize inbreeding and retain genomic variation, and to promote adaptive potential of the reintroduced population. While genetic variation for the source populations was very low, we found no decrease in genetic diversity or increase in inbreeding across the program. These genetic findings support the efforts made by local communities and will further inform future reintroductions as part of a collaborative conservation framework. We expand on our empirical case study by describing a theoretical framework for integrating conservation genomics research with community‐led conservation management programs and identifying the benefits of such a collaboration. Our study highlights the importance of multifaceted and integrated conservation management approaches to effectively protect and manage threatened species. [ABSTRACT FROM AUTHOR]

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Reproductive rate has been suggested to have a positive effect on the amount of habitat loss a species can tolerate while emigration from habitat patches has been suggested to have both positive and negative effects. Forest fragmentation has been suggested to have negative effects on forest species. We determined the extinction threshold for 12 species of saproxylic (dead wood dependent) longhorned beetles (Coleoptera: Cerambycidae) using trap catch data from Ontario, Canada. We also determined the maximum egg production of each species and whether they were likely to move outside of forest patches. We found a strong negative relationship between reproductive rate and the minimum habitat amount required for species presence. This relationship is obscured if the scale of investigation is not appropriate for the study organism. As well, species caught moving outside forest habitat had lower extinction thresholds than species not caught moving outside forest but this was not significant after accounting for reproductive rate. Fragmentation did not have an effect on the minimum habitat requirements. These relationships can inform predictions of which species will be most affected by habitat loss. [ABSTRACT FROM AUTHOR]

Mahalanobis Distance (D²) Statistic is a multivariate statistical method that has been used to model habitats occupied by wildlife and plant species. The output, whether standardized squared distance or probability values, represents the similarity of a given set of values with those of an optimum habitat configuration defined exclusively by sites where the species of interest is known to occur. Typically, all principal components with nonzero eigenvalues are used to calculate D² values. We partitioned D² into contributions from individual principal components (PCs) and selected PCs corresponding to relatively invariant aspects of the environment across all use sites to formulate D²(k). Partitioned Mahalanobis D²(k) represents the similarity of a given set of values with those of "minimum" habitat requirements of the species as defined by occupied sites using the k subset of principal components. We created a GIS-based model of the habitat surrounding 39 confirmed timber rattlesnake hibernacula on the Madison County Wildlife Management Area in northwest Arkansas, USA, using slope, aspect, elevation, and 11 physical soil attributes. We retained 4 of 15 principal components in D²(k = 4) calculations, and minimum habitat requirements corresponded to a combination of moderate slope, south to southwest facing slopes, and medium to high elevations. We used bootstrap and cross-validation techniques to examine the stability of the correlation matrix and the effect of each site on overall D²(k) values. The D²(k = 4) model specifically highlighted habitats similar to known rattlesnake hibernacula. We present a method to translate the probability surface into a qualitative data layer useful in making management decisions by examining the cumulative distributions of the percentages of (1) hibernacula correctly classified and (2) the study area predicted. We selected the probability threshold that maximized the predictive gain by... [ABSTRACT FROM AUTHOR]

Urban parks play an important role in urban ecosystems with multifunctional services. Park size is one of the important attributes to explain the potential capacity of urban parks. In recent years, the number of studies that focus on the relationship between park size and ecosystem services in the context of ecosystem services has been increasing. This study aims to focus on investigating the relationship between ecosystem services and urban park size. The Web of Science online databases were searched using the keywords "green space", "size" and "urban" as well as related terms. A total of 129 papers meeting the inclusion criteria were examined within the scope of the research aims. The results obtained from the systematic search were summarized and presented in the three categories with sub-categories: (i) cultural services with sub-categories of physical activity (n = 42) and housing prices (n = 10), (ii) supporting services with sub-categories of fauna (n = 44), and flora (n = 3) and (iii) regulating services with sub-categories of microclimate (n = 25) and air quality (n = 5). The results indicated that park size influences a wide range of services by providing more spaces for physical activities, increasing housing prices, creating habitats for birds, insects, and bats, and effects on their richness, diversity and density, increasing the cooling effect capacity and reducing air pollution of urban parks. In conclusion, a comprehensive approach is needed, recognizing the potential of both large and small green spaces to optimize ecosystem services delivery, promote resilience, and enhance urban well-being. This includes considering supply and demand aspects and improving measurement methods. Furthermore, exploring optimal improvements across diverse park sizes remains a promising avenue for research, contributing to the development of more efficient urban green spaces. [ABSTRACT FROM AUTHOR]

Reforestation practices have intensified in the Mississippi Alluvial Valley (MAV) of the United States of America with the aid of Farm Bill programs during the past three decades. Increases in reforested land also enhance possibilities to restore once-abundant but currently sparse species, such as eastern wild turkeys (Meleagris gallopavo silvestris) in the MAV. However, it is unknown whether <20-year-old hardwood regeneration provides a suitable habitat for re-establishing wild turkey populations in the MAV. We translocated wild turkeys to two study sites in reforested areas of the MAV. We monitored 74 wild turkeys' habitat use and resource selection using radio telemetry from February 2009 to June 2010. We developed land use and land cover maps for the resource selection analysis of translocated wild turkeys. We found that turkey habitat use varied by site, sex, season, land cover type, and distance to mature hardwoods. Habitat use by wild turkeys decreased as distance to mature hardwood forest increased. Female wild turkeys used more hardwood regeneration during nesting and post-nesting seasons than during pre-nesting seasons. Although wild turkeys did not use regenerating and mature hardwood forests to the same extent, management of these forests appears critical to restoring wild turkeys in the MAV. [ABSTRACT FROM AUTHOR]

Headwater streams support vital aquatic habitat yet are vulnerable to changing climate due to their high elevation and small size. Coldwater fish are especially sensitive to the altered streamflow and water temperature regimes during summer low flow periods. Though previous studies have provided insights on how changes in climate and alterations in stream discharge may affect habitat availability for various native cutthroat trout species, suitable physical habitats have not been evaluated under future climate projections for the threatened Greenback Cutthroat Trout (GBCT) native to headwater regions of Colorado, USA. Thus, this study used field data collected from selected headwater streams across the current distribution of GBCT to construct one‐dimensional hydraulic models to evaluate streamflow and physical habitat under four future climate projections. Results illustrate reductions in both predicted streamflow and physical habitat for all future climate projections across study sites. The projected mean summer streamflow shows greater decline (−52% on average) compared to the projected decline in mean August flow (−21% on average). Moreover, sites located at a relative higher elevation with larger substrate and steeper slope were projected to experience more reductions in physical habitat due to streamflow reductions. Specifically, streams with step‐pool morphologies may experience grater changes in available habitat compared to pool‐riffle streams. Future climate change studies related to coldwater fish that examine spatial variation in flow alteration could provide novel data to complement the existing literature on the thermal characteristics. Tailoring reintroduction and management efforts for GBCT to the individual headwater stream with adequate on‐site monitoring could provide a more holistic conservation approach. [ABSTRACT FROM AUTHOR]

Understanding how changes in landscape properties influence common species is relevant as it allows us to identify patterns that could be shared with co-distributed species that occupy the same landscapes. The northeastern United States (NE-USA: New York state and the six states of New England) is heavily urbanized and affected by continuous and prolonged anthropogenic activities, leading to intensive landscape fragmentation and loss of natural forests. Here, we used a landscape genetics approach to explore the genetic diversity and structure of the Southern Flying Squirrel, Glaucomys volans , and how resulting patterns may be related to landscape fragmentation and forest loss in the NE-USA. To study G. volans genetic variation and population structure, we amplified and genotyped 10 microsatellites loci from DNA extracted from tissue samples stored in biological collections and natural history museums. To assess the influence of landscape on gene flow and connectivity, we used two genetic distances metrics–proportion of shared alleles and codominant marker, and tested two landscape cost models approaches–least cost path and isolation by resistance. We identified three genetic clusters, with low but significant genetic differentiation between them. We did not find correlation between geographic distance and genetic variation in these populations. According to landscape models, land cover and elevation were the best predictors of genetic connectivity of G. volans , although were poorly related to genetic distances. Our results suggest that gene flow occurs between G. volans populations across the NE-USA despite the changed landscape configuration, implying potential dispersal of individuals between patches. Nonetheless, individuals from the eastern periphery of the distribution may have been temporarily isolated in the past due to historical deforestation. The current regeneration of hardwood forests represents a positive outlook for the genetic integrity of G. volans populations in the NE-USA because more possibilities for corridors and patches of habitable forests emerge. These changes would improve the connectivity of the species in the region and avoid possible local extinction events. [ABSTRACT FROM AUTHOR]

The Sardinian wetlands belong to the Sardinia‐Corsica corridor of the central eastern Mediterranean bird flyway. They supply the food and shelter for many waterbird species and act as stopover sites during migratory journeys. Despite policies and laws of the European Union, the Sardinian wetlands are severely threatened by anthropic activities and ongoing climate change, making the condition of the associated avifauna critical.We (a) inventoried the avian metacommunity of the largest coastal wetlands in Sardinia during the summer period, (b) investigated the metacommunity structure, (c) quantified the effects of wetland attributes on avian diversity at species and guild level and (d) predicted future changes in species composition of this metacommunity.We recorded 60 bird species (of which 21 belonged to Annex I of the Birds Directive). The metacommunity structure resulted was significantly nested and non‐modular. Salinity negatively affected the presence of 48 species out of 60, followed by tourism pressure (44 species), wetland isolation (42 species) and water discharges (36 species). The mean water level resulting from artificial regulation for anthropic activities was too high for 63% of the species, which disadvantaged primarily small waders, species feeding on invertebrates and trans‐Saharan migrants. In addition, water‐level fluctuations (that would favour avian diversity) were prevented by artificial regulation during the summer period in many wetlands, producing further negative effects on the avifauna. We found 45% of the recorded bird species at risk of disappearance from this avian metacommunity.Synthesis and applications. Our study indicates that, as things stand, the avian metacommunity of the Sardinian wetlands is destined to experience reductions in the short term and mid‐term. This decline will be accelerated by increased saltwater intrusions due to sea‐level rise. Nevertheless, the nested and non‐modular structure of this avian metacommunity would allow for pro‐active conservation measures (e.g. restriction for tourism activities, construction of artificial dune cordons to minimize saltwater intrusions, water‐level regulation that keeps into account also the ecological requirements of waterbird species) to counteract the effects of current and future threats. [ABSTRACT FROM AUTHOR]

River flow is closely linked to survival of human cultures, the economies providing sustainable livelihoods, and the general well-being of the society. The concept of environmental flows has been globally accepted and efforts are being made worldwide to restore and maintain riverine ecosystems. Assessment of environmental flow requirement of rivers is in an infancy stage in India; this has not been done for most of the rivers including those flowing west to the Western Ghats. In this study, the environmental flow (EF) requirements of the Chaliyar River, a major river flowing westwards of the Western Ghats (WG) in Kerala, India, were estimated using hydrologic and hydraulic methods. This was done using the Indicators of Hydrologic Alterations (IHA), and the Wetted Perimeter (WP) methods. Three major sub-basins of the Chaliyar namely, Chaliyar Main Stream, Punnapuzha, and Karimpuzha were considered in this study. This study concentrated on the low flow periods. Environmental Flow Components (EFC), and Flow Duration Curve (FDC) from the IHA, and Critical Minimum Flow (CMF) from the wetted perimeter method were compared in this study. The environmental flow requirements for the low flow season for the three streams, namely, Chaliyar Main, Punnapuzha, and Karimpuzha, computed using the IHA are 1.32, 1.33, and 0.59 m3/s respectively. The corresponding values obtained by the wetted perimeter method are 1.37, 1.25, and 0.75 m3/s respectively. This indicates that the results obtained using these two methods are in good agreement with each other. [ABSTRACT FROM AUTHOR]

Ecological communities are structured by combinations of biotic and abiotic factors acting at different spatial scales. However, the relative influence of the different scale‐related variables on assemblage composition is poorly understood, despite being key to the effective and efficient management of fluvial ecosystems. We took advantage of the relatively recent and well‐studied history of salmonid introductions in Patagonia to evaluate if non‐native species show different patterns of association with abiotic factors depending on the spatial scale of the environmental filter. We used a hierarchical approach to characterised environmental variables at the basin and reach scales to assess their influence on the presence, abundance and structure of the salmonid assemblages in breeding streams. We saw no evidence that presence/absence patterns of salmonid distribution were driven by landscape variables, except for those basins with physical environmental barriers to colonisation. However, we did find evidence for relative abundances being influenced by climatic and geomorphological variables (e.g., precipitation and relief). Our results do not support a scenario in which any of the salmonid species modulates the distribution of the other species, suggesting that interference has played only a minor role in determining current fish distribution in fluvial systems of the region. Instead, current patterns of presence and abundance of salmonids are best explained as the product of environmental filters. Our findings contribute to our understanding of the ecology of individual species and provide insight into the mechanisms structuring fish assemblages in Southern Hemisphere's lotic systems. [ABSTRACT FROM AUTHOR]

The expected change in fitness under inbreeding due to deleterious recessive alleles depends on the amount of inbreeding load harbored by a population, that is, the load of deleterious recessive mutations concealed in the heterozygous state, and the opposing effect of genetic purging to remove such a load. This change in fitness can be thus predicted if an estimate of the inbreeding load and the purging coefficient (the parameter that quantifies the amount of purging) are available. These two parameters can be estimated in pedigreed populations, as has been shown for populations under random mating. A question arises whether these parameters can also be estimated under other breeding systems as well as whether they allow accurate prediction of the corresponding expected change in fitness. In conservation programs, it is usually recommended to preserve genetic diversity by equalizing contributions from parents to progeny and avoiding inbred matings. Regular systems of inbreeding have also been proposed as breeding conservation strategies to purge the inbreeding load. Using computer simulations, we first test a method to jointly estimate the initial inbreeding load and the purging coefficient in populations subjected to equalization of parental contributions, circular mating, and partial full‐sib mating. Then, using the expected values of the inbreeding coefficient and the variance of family size, as well as the estimates of the inbreeding load and the purging coefficient, we make simple predictions of the change in fitness over generations under these breeding systems and compare them with simulation results. We discuss how these fitness predictions can help undertaking conservation designs under different breeding scenarios. [ABSTRACT FROM AUTHOR]

Jaguars and pumas are top-predator species in the Neotropics that are threatened by habitat destruction, illegal poaching of their body parts and their favored prey, and by the human–wildlife conflicts that arise when predators attack livestock. Much of the remaining felid habitat in the Americas is in protected nature reserves that are too small and isolated to support local populations. Surrounding forests therefore play a vital role in felid conservation. Successful long-term conservation of these two felids requires evidence-based knowledge of their biological and ecological requirements. We studied population distributions of jaguars and pumas and their prey in and between two small, private reserves of the Northern Yucatán Peninsula, Mexico, with areas of 25 and 43 km2. During 2 years of camera trapping (2015 and 2016), we detected 21 jaguars, from which we estimated an average space requirement of 28–45 km2/individual. Dietary niche overlap exceeded random expectation. The most frequently occurring prey items in jaguar and puma diets were collared peccary and deer. Jaguar also favored nine-banded armadillos and white-nosed coati, while puma favored canids. Both felids avoided ocellated turkey. Overall, diet of jaguars was less species-rich, but similar in niche breadth, to that of pumas. A fluid use of space by both species, in 2015 tending toward mutual attraction and in 2016 toward partial exclusion of pumas by jaguars, combined with the high dietary overlap, is consistent with a dominance hierarchy facilitating coexistence. Jaguars and pumas favor the same prey as the people in local communities who hunt, which likely will intensify human–wildlife impacts when prey become scarce. We conclude that even small reserves play an important role in increasing the continuity of habitat for prey and large felids, whose generalist habits suppress interspecific competition for increasingly limiting prey that are largely shared between them and humans. [ABSTRACT FROM AUTHOR]

Conservation planning is designed to optimize conservation actions when only limited resources are available for managing habitats and mitigating threats, and excels at selecting reserve networks that protect the largest number of species. However, the spatial optimization of the protection of multiple species can be complicated by interactions among those species and incompatibilities in their habitat needs. The challenge is to identify an optimal solution when two species with similar habitat needs cannot co-occur. We propose here a new approach to find the optimal conservation planning solution in cases of species incompatibilities, and demonstrate this solution for a 144 km 2 area (a 160,000-cell grid) in northern Wisconsin. Specifically, our study objectives were to simultaneously (a) identify the smallest area needed to meet minimum habitat requirements for every species considered, (b) maximize the compactness of that area, and (c) avoid any overlap between species with incompatible habitat requirements. We found an optimized solution based on potential habitat models for 19 bird species using a novel application of mixed integer linear programming, with a clustering approach suited for large cell arrays. Under this solution, 9.9% of the study plot was sufficient to meet the minimum requirements for every species considered, maximize the compactness of that area, and avoid any overlap between species with incompatible habitat requirements. Our results are useful to assist managers in providing well-connected, sufficient habitat to at-risk species while minimizing costs and land use conflicts. [ABSTRACT FROM AUTHOR]

Salmonids are of immense socio‐economic importance in much of the world, but are threatened by climate change. This has generated a substantial literature documenting the effects of climate variation on salmonid productivity in freshwater ecosystems, but there has been no global quantitative synthesis across studies. We conducted a systematic review and meta‐analysis to gain quantitative insight into key factors shaping the effects of climate on salmonid productivity, ultimately collecting 1321 correlations from 156 studies, representing 23 species across 24 countries. Fisher's Z was used as the standardized effect size, and a series of weighted mixed‐effects models were compared to identify covariates that best explained variation in effects. Patterns in climate effects were complex and were driven by spatial (latitude, elevation), temporal (time‐period, age‐class), and biological (range, habitat type, anadromy) variation within and among study populations. These trends were often consistent with predictions based on salmonid thermal tolerances. Namely, warming and decreased precipitation tended to reduce productivity when high temperatures challenged upper thermal limits, while opposite patterns were common when cold temperatures limited productivity. Overall, variable climate impacts on salmonids suggest that future declines in some locations may be counterbalanced by gains in others. In particular, we suggest that future warming should (1) increase salmonid productivity at high latitudes and elevations (especially >60° and >1500 m), (2) reduce productivity in populations experiencing hotter and dryer growing season conditions, (3) favor non‐native over native salmonids, and (4) impact lentic populations less negatively than lotic ones. These patterns should help conservation and management organizations identify populations most vulnerable to climate change, which can then be prioritized for protective measures. Our framework enables broad inferences about future productivity that can inform decision‐making under climate change for salmonids and other taxa, but more widespread, standardized, and hypothesis‐driven research is needed to expand current knowledge. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Climate change and habitat loss have been identified as the main causes of species extinction. Forest regeneration and protected areas are essential to buffer climate change impacts and to ensure quality habitats for threatened species. We assessed the current and future environmental suitability for the maned sloth, Bradypus torquatus , under both future climate and forest restoration scenarios, using ecological niche modeling. We compared environmental suitability for two Evolutionarily Significant Units (ESUnorth and ESUsouth) using two climate change scenarios for 2070, and three potential forest regeneration scenarios. Likewise, we evaluated the protection degree of the suitable areas resulting from the models, according to Brazilian law: PA—Protected Areas; PPA—Permanent Protection Areas (environmentally sensitive areas in private properties); and LR—Legal Reserves (natural vegetation areas in private properties). Finally, we calculated the deficit of PPA and LR in each ESU, considering the current forest cover. Forest regeneration might mitigate the deleterious effects of climate change by maintaining and increasing environmental suitability in future scenarios. The ESUnorth contains more suitable areas (21,570 km²) than the ESUsouth (12,386 km²), with an increase in all future scenarios (up to 45,648 km² of new suitable areas), while ESUsouth might have a significant decrease (up to 7,546 km² less). Suitable areas are mostly unprotected (ESUnorth—65.5% and ESUsouth—58.3%). Therefore, PPA and PA can maintain only a small portion of current and future suitable areas. Both ESUs present a high deficit of PPA and LR, highlighting the necessity to act in the recovery of these areas to accomplish a large-scale restoration, mitigate climate change effects, and achieve, at least, a minimum forested area to safeguard the species. Notwithstanding, a long-term conservation of B. torquatus will benefit from forest regeneration besides those minimum requirements, allied to the protection of forest areas. [ABSTRACT FROM AUTHOR]

Insect herbivores can be limited by host plants in two ways: density-dependent competition for food resources or density-independent search time limitation. Our understanding of density-dependent host plant limitation is relatively well developed and well integrated into conservation plans for at-risk insects. Search time limitation, a density-independent process, is much less well developed. Here, we explore both mechanisms using empirically based models of monarch butterfly population dynamics. These mechanisms differ fundamentally in their predictions: resource competition leads to matching of herbivore densities to host plant densities, and visible competition via consumption of host plants. Search time limitation leads to changes in population growth rate that can cause herbivore numbers to decline when host plant densities are constant. Search time limitation also implies that host plants can limit herbivores, even when many individual plants are uneaten. For monarch butterflies, our calculations suggest that many parts of North America have host plant densities below the threshold for search time limitation, which contrasts with the typical assumption of resource competition. More generally, incorporating search time limitation into conservation plans is important for reframing our understanding of how host plants limit insect herbivores in highly fragmented landscapes. [ABSTRACT FROM AUTHOR]

The establishment of the minimum size for a viable population (MVP) has been used as a guidance in conservation practice to determine the extinction risks of populations and species. A consensus MVP rule of 50/500 individuals has been attained, according to which a minimum effective population size of Ne = 50 is needed to avoid extinction due to inbreeding depression in the short term, and of Ne = 500 to survive in the long term. However, the large inbreeding loads (B) usually found in nature, as well as the consideration of selection affecting genetic diversity, have led to a suggestion that those numbers should be doubled (100/1000). Purging of deleterious mutations can also be a main factor affecting the suggested rules. In a previous simulation study, the reduction of B by the action of purging pointed towards an MVP intermediate between the two rules for short term survival. Here, we focused on the consequences of purging in the establishment of MVPs for long term survival. We performed computer simulations of populations under the action of purging, drift, new mutation, and environmental effects on fitness to investigate the extinction times and the loss of genetic diversity for a range of effective population sizes. Our results indicate that purging can reduce the MVP needed for a population to persist in the long term, with estimates close to Ne = 500 for species with moderately large reproductive rates. However, MVP values appear to be of at least Ne = 1000 when the species´ reproductive rates are low. [ABSTRACT FROM AUTHOR]

Wetland birds are undergoing severe population declines in North America, with habitat degradation and wetland loss considered two of the primary causes. Due to the cryptic nature of many wetland bird species, the ecological conditions (e.g., matrix composition) that influence bird occupancy, and the relevant spatial scales at which to measure bird responses, remain unclear but may affect inference about wetland use and suitability. We conducted wetland bird surveys at 477 points across northeastern Illinois and northwestern Indiana within the highly urbanized landscape surrounding Chicago. Using remotely sensed land cover data, we built occupancy models for 10 wetland bird species (American Coot Fulica americana, Black‐crowned Night‐Heron Nycticorax nycticorax, Blue‐winged Teal Anas discors, Common Gallinule Gallinula galeata, Least Bittern Ixobrychus exilis, Marsh Wren Cistothorus palustris, Pied‐billed Grebe Podilymbus podiceps, Sora Porzana carolina, Swamp Sparrow Melospiza georgiana, and Virginia Rail Rallus limicola) to quantify their responses to wetland cover types (emergent wetland, forested wetland, riverine wetland, and freshwater pond) and urbanization at four spatial scales (200‐, 400‐, 800‐, and 2000‐m radial distances). We also included the distance to Lake Michigan as a covariate in occupancy models to account for ecological differences between coastal and inland wetlands. We found that relationships between land cover types and occupancy differed by species, as did the spatial scale of support. Generally, the presence of emergent wetlands or ponds at immediate (200 m) and local (400 m) spatial scales within the surrounding matrix was positively associated with wetland bird occupancy. Contrary to expectations, we did not find support for a negative relationship between urbanization and occupancy for most focal species, indicating that birds are using available wetland habitats despite surrounding development. While future research should evaluate management strategies at the watershed scale, our findings suggest that wetland conservation planning at immediate and local scales is likely to promote bird habitat use within highly modified landscapes of the Upper Midwestern United States. [ABSTRACT FROM AUTHOR]

Lahontan cutthroat trout Oncorhynchus clarkii henshawi have experienced massive declines in their native range and are now a threatened species under the US Endangered Species Act. A key management goal for this species is re-establishing extirpated populations using translocations and conservation hatcheries. In California USA, two broodstocks (Pilot Peak and Independence Lake) are available for reintroduction, in addition to translocations from wild and naturalized sources. Pilot Peak and Independence Lake fish are hatchery stocks derived from native fish from the Truckee River basin and used for recovery activities in the western Geographic Management Unit Areas only, specifically within the Truckee River basin. Yet suitability of these sources for re-introduction in different ecosystem types remains an open and important topic. We conducted growth experiments using Lahontan cutthroat trout stocked into Sagehen Creek, CA, USA. Experiments evaluated both available broodstocks and a smaller sample of fish translocated representing a naturalized population of unknown origin from a nearby creek. Fish from the Independence Lake source had significantly higher growth in weight and length compared to the other sources. Further, Independence Lake fish were the only stock that gained weight on average over the duration of the experiment. Our experiments suggest fish from the Independence Lake brood stock should be considered in reintroduction efforts. [ABSTRACT FROM AUTHOR]

Abstract: This paper is based on a study conducted by Sasakawa International Center for Space Architecture (SICSA) between September 2008 and February 2009. SICSA has been awarded key roles in helping two aerospace company teams plan living and working accommodations for early lunar surface missions. SICSA has major conceptual design responsibilities on teams headed by Boeing and ILC-Dover which were separately selected out of more than 20 competing proposals for two out of three total NASA study contracts. Major study priorities were to determine minimum habitat requirements essential to keep crews alive and safe from harm during the first month-long missions, and then expand these accommodations as operations, facilities and amenities are extended. This paper discusses important points of radiation protection design options and known radiation protection materials applications with a special emphasis upon comparative mass implications for several proposed habitat configuration concepts. These comparisons are correlated with shielding surface area rather than actual mass estimates due to current data uncertainties regarding a number of issues: unresolved questions concerning how much radiation protection will be mandated, what mitigation strategies will be selected, what types and thicknesses of materials will be used, and how much of the total allowable module mass can be allocated for this purpose. [ABSTRACT FROM AUTHOR]

Habitat degradation combined with climate change increases the threat of extinction for stream fishes. In response to these threats, efforts to reestablish species within formerly occupied streams or translocation to suitable areas may be effective conservation strategies. In the absence of historic species presence data, identifying locations where suitable habitat exists across many fluvial habitats may limit the effectiveness of reestablishments. We present an approach that ranks habitat for stream fish reestablishment over large areas using best available information. Using the locally extirpated Arctic grayling (Thymallus arcticus) in Michigan, USA as an example, we integrate information on species preferences and relationships between species with similar habitat requirements and landscape predictors of habitat to rank stream suitability. We find that unfragmented streams throughout the historical range of Arctic grayling and areas previously unoccupied by the species are potential locations for conservation action. However, we note that projected increases in summer water temperatures may reduce the amount of thermally suitable habitat in some top-ranked locations by up to 30%. Given its inherent flexibility in data requirements, our landscape-level approach may be a valuable tool that supports planning for species reestablishment. [ABSTRACT FROM AUTHOR]

Variation in seasonal survival rates, densities and growth rates of coastal cutthroat trout (Oncorhynchus clarkii clarkii) were assessed across a size gradient of small, forested streams in the Pacific Northwest. We used a robust, mark‐recapture study, stratified seasonally to estimate monthly survival rates of trout in coastal British Columbia (not including young‐of‐the‐year). Survival estimates showed that the summer season had the lowest monthly survival rates (0.907) across all streams in our study (0.927 remainder of year). Within the size range of the seven small streams studied, low‐flow habitat availability (defined by residual pool depth in summer) was the best predictor of mean monthly survival rates, supporting the hypothesis that trout survival increases with the quantity of aquatic habitat, particularly depths of residual pools. In addition, there was an asymptotic relation between water depth and survival rates, where beyond ~20 cm of residual pool depth, greater depth did not confer greater rates of trout survival. Growth rates in all but the largest stream were also lowest during summer. While densities tended to be higher in streams with greater residual depth, this was not significant. Body mass in a given season was a good predictor of survival to the next sampling period. The distribution and success of resident cutthroat trout populations in small streams appear to be constrained by summer low‐flow periods and specific geomorphologies that support deeper pools. [ABSTRACT FROM AUTHOR]

Understanding the impacts of global change on ecological communities is a major challenge in modern ecology. The gain or loss of particular species and the disruption of key interactions are both consequences and drivers of global change that can lead to the disassembly of ecological networks. We examined whether the disruption of a hummingbird–mistletoe–marsupial mutualism by the invasion of non‐native species can have cascading effects on both pollination and seed dispersal networks in the temperate forest of Patagonia, Argentina. We focused on network motifs, subnetworks composed of a small number of species exhibiting particular patterns of interaction, to examine the structure and diversity of mutualistic networks. We found that the hummingbird–mistletoe–marsupial mutualism plays a critical role in the community by increasing the complexity of pollination and seed dispersal networks through supporting a high diversity of interactions. Moreover, we found that the disruption of this tripartite mutualism by non‐native ungulates resulted in diverse indirect effects that led to less complex pollination and seed dispersal networks. Our results demonstrate that the gains and losses of particular species and the alteration of key interactions can lead to cascading effects in the community through the disassembly of mutualistic networks. [ABSTRACT FROM AUTHOR]

• Bechsteińs Bat and woodpeckers explicitly select for old-growth habitat features. • Stands with basal areas of >4 m2 ha−1 of habitat-trees (DBH > 50 cm) are preferred. • High tree cavity densities reveal a major importance on forest and stand scale. • Close link between trees with limb break offs and tree cavity density. • Injured but still vital, large trees play a major role for high habitat quality. Old-growth forests provide valuable habitats for bat and woodpecker species worldwide. However, the abundance of old-growth related habitat features is frequently reduced in managed forests. Bechstein's Bat (Myotis bechsteinii , Kuhl 1817) is globally restricted to old-growth deciduous forests in Europe and therefore a species of high European conservation priority. Since the species prefers woodpecker cavities for roosting, woodpeckers are keystone species for Bechstein's Bat. We surveyed woodpecker activity and forest structural features within 16 roost sites of Bechsteińs Bat and a random sample from the surrounding managed forest within the centre of the global distribution of Bechsteińs Bat. We found above-average quantity of old-growth related habitat features in the roost sites of Bechstein's Bat. Five of six occurring woodpecker species revealed significantly higher densities in the roost sites of Bechstein's Bat, demonstrating a distinct preference of the woodpeckers and the bat in managed forests for old, deciduous stands with high basal areas of large living trees (DBH > 50 cm), bearing deadwood structures and highest available tree cavity densities. Furthermore, when comparing the direct surroundings of roost trees to their wider surroundings (16 ha), cavity density and other old-growth features reached their maxima in the direct surroundings of roost trees (mean = 19.3 cavities ha−1), demonstrating a distinct habitat selection of Bechsteińs Bat for patches with maximum available cavity density on large and fine spatial scale. We found a close relation between the basal area of trees with limb break offs (>20 cm base diameter) and tree cavity density, which leads us to the conclusion that specifically injured but still vital, large trees play a major role for the development and long-term persistence of tree cavities. Finally, our analyses revealed a threshold of 20 (DBH > 50 cm) or 10 (DBH > 70 cm) large deciduous trees bearing deadwood structures per ha to fulfil the minimum habitat requirements of the woodpeckers and Bechstein's Bat. Obviously, Bechsteińs Bat and the associated woodpeckers explicitly selected forest patches, which most closely resembled primeval forest benchmarks, emphasising the importance of maintaining and developing forest patches, providing the mentioned habitat features within managed forests. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quantitative relationships between river discharge and hydraulic habitat availability for key taxa are important elements of environmental flow assessment. We used radiotelemetry to examine diel patterns of habitat use by tracking the locations of 17 juvenile Sooty grunter (Hephaestus fuliginosus) over a 10‐day period during the late dry season in a river in the wet–dry tropics of northern Australia. Habitat use data were integrated with a hydrodynamic model to identify preferred hydraulic habitat and explore different river discharge scenarios to assess the potential effects of water abstraction on habitat availability. Sooty grunter exhibited a strong preference for shallow, fast flowing mesohabitat (riffles and runs). Hydraulic microhabitat preference was modelled using generalised additive mixed‐effect models (GAMMs) and showed no significant difference in microhabitat selection between day and night. Habitat criteria developed from a combined day‐night GAMM were defined as locations with velocities of 0.26–1.42 m s−1 and depths <0.69 m. Hydrodynamic modelling of river discharge scenarios in the study reach showed that the area of preferred habitat was highest at 8 m3 s−1, with large declines in habitat area under low flows (61% decline in habitat area at 0.5 m3 s−1 compared to the discharge of 2.8 m3 s−1 at the time of radio‐tracking). While the study focusses on a single species, our findings demonstrate the broad applicability of radiotelemetry as a means of quantifying the diel hydraulic habitat requirements of riverine fish to support the objective determination of environmental flow regimes. [ABSTRACT FROM AUTHOR]

Threshold nonlinearities in the relationship between island area and species richness can result in dramatic declines in richness with a seemingly small decline in area near the threshold. What is not known, is whether threshold declines in richness are also accompanied by nonlinear changes in functional trait space and non‐random shifts of trait group composition in response to declining area.Plant species richness was recorded, and four functional diversity (FD) indices calculated based on 12 traits for 76 tree species in 5,082 plots (5 × 5 m) on 29 islands in the Thousand Island Lake region, Zhejiang, China. We tested for threshold nonlinearities in richness and FD relationships using segmented regression, with randomized resampling using a null model to account for potential sampling artefacts. We clustered tree species into trait groupings based on trait dissimilarity, and used multinomial segmented models to test whether threshold area effects on FD were associated with shifts in trait group composition.Species richness and three of the four FD indices showed significant threshold nonlinearities with declining island area below a threshold of ca 1.16–6.88 ha. K‐means clustering identified two trait groups, reflecting species at the 'fast' versus 'slow' ends of the trait spectrum. Significant area thresholds in trait group composition were driven by increasing relative richness, but decreasing relative abundance, of species with resource‐conservation traits on islands below the threshold.Synthesis. We found a threshold collapse in richness on islands below c. 1 ha, resulting in a significant decrease in functional trait space (functional richness) and an increase in the degree of niche differentiation among species in the community (functional divergence) on small islands. Threshold effects were associated with non‐random re‐assembly of trait group composition, favouring the relative richness of species at the 'slow' resource‐conservation end of the trait spectrum, but the relative abundance of a few species with 'fast' resource‐acquisition traits. These results suggest that disturbance‐driven dynamics potentially drive a functional shift in the ecosystem state at a critical threshold. We show that a minimum critical habitat area is required to maintain functional diversity in woody plant communities. [ABSTRACT FROM AUTHOR]