Regional Extinction Risk Research Articles

Centralized red muscle in Odontaspis ferox and the prevalence of regional endothermy in sharks.

The order Lamniformes contains charismatic species such as the white shark Carcharodon carcharias and extinct megatooth shark Otodus megalodon, and is of particular interest given their influence on marine ecosystems, and because some members exhibit regional endothermy. However, there remains significant debate surrounding the prevalence and evolutionary origin of regional endothermy in the order, and therefore the development of phenomena such as gigantism and filter-feeding in sharks generally. Here we show a basal lamniform shark, the smalltooth sand tiger shark Odontaspis ferox, has centralized skeletal red muscle and a thick compact-walled ventricle; anatomical features generally consistent with regionally endothermy. This result, together with the recent discovery of probable red muscle endothermy in filter feeding basking sharks Cetorhinus maximus, suggests that this thermophysiology is more prevalent in the Lamniformes than previously thought, which in turn has implications for understanding the evolution of regional endothermy, gigantism, and extinction risk of warm-bodied shark species both past and present.

Using range size to augment regional priority listing of charismatic insects

Extinction risk assessments are challenged by population data deficiencies, especially at large scales and for diverse taxa like insects. We generally have a better handle on insect distributions than on their population sizes and trends. As a composite expression of other traits and population factors, geographic range size may compensate for lagging population data and extend regional status coverage to more insect species over more jurisdictional area, at least within the relatively accessible and charismatic taxa. We tested this using a range-based index of regional extinction risk and two “incomplete” regional status assessments for North American dragonflies and damselflies (Odonata). The range index revealed signatures for generalizing High-concern and Low-concern status throughout the regional jurisdictions and Odonata species pools. Using the High-concern signature, we identified 38 regional priority candidates that currently lack regional concern status in the Midwest United States, and 15 candidates in central Canada where regional status was never assessed. Our robust range index covered almost 10 % of the world's described Odonata species and could be adapted to other regional jurisdictions and insect groups supported by strong community science. Range size alone may offer a workable approach for estimating regional extinction risk and facilitating prioritization of charismatic insects in regions lacking population trend data and IUCN Red Lists.

Population distribution, connectivity and differentiation of Indo‐Pacific humpback dolphins in Chinese waters: Key baselines for improving conservation management

Abstract Humpback dolphins (Sousa spp.), throughout their distribution ranges, are often designated as flagship species for coastal ecosystem conservation. Most of the early research on humpback dolphins was carried out in Chinese waters, and in the last two decades, numerous studies have provided abundant conservation‐valuable findings. In this study, a systematic review was conducted to gain a comprehensive understanding of the distributional ecology of humpback dolphins in Chinese waters, to establish an updated national knowledge base about key conservation baselines on this flagship species. Currently, there are at least eight main distribution areas of humpback dolphins along the coast of southern China, representing a clear picture of place‐based conservation units. However, the overall biogeographical distribution pattern is discontinuous, and existing marine protected areas are far from sufficient to protect these key areas for the survival of humpback dolphins. Based on the photo‐identification technique, cross‐matching of humpback dolphin individuals revealed extremely low inter‐population connectivity among most of the known populations. Genetic studies suggested that several examined populations have low haplotype diversity levels, with limited inter‐population gene flow. Morphological and behavioural evidence also supports population differentiation among geographical locations. These findings provide key baselines for the promotion of conservation management initiatives for humpback dolphins in Chinese waters. All recognizable geographical populations, together with each key habitat, should be considered as independent conservation units. With small distribution areas, low genetic diversity and unfavourable geographical isolation, several populations may be at a high risk of regional extinction. A country‐led scheme with cross‐regional collaboration is required for science‐based, action‐focused and timely conservation efforts. Future conservation management initiatives should aim to increase or at least maintain key habitats, inter‐population connectivity, population‐level genetic diversity and effective population size.

Status of the largetooth sawfish in Ecuador and Peru, and use of rostral teeth in cockfighting

Sawfish conservation is a critical concern, yet insufficient baseline data on their presence and status has hindered conservation efforts at national and regional levels. Between 2015 and 2017, interviews were conducted in fishing communities in Ecuador and Peru to assess the historical and current status of largetooth sawfish Pristis pristis. Interviews with cockfighting practitioners in Peru aimed to gauge the use and demand for cockfighting spurs made from sawfish rostral teeth. Our study confirmed the presence of largetooth sawfish in the waters of both countries. Importantly, some fishermen are aware of the value of rostral teeth, which may influence their decisions not to release sawfish alive. Of the interviewees (n = 188), a majority (88%) reported a perceived decline in sawfish abundance during their lifetimes. In this region, as in other sawfish habitats, bycatch and habitat loss pose significant threats. To address these challenges, potential actions include strategic conservation planning, reinforced national and international trade regulations, education campaigns targeting the cockfighting community, public outreach initiatives, and the live release of sawfish specimens. These efforts can enhance the conservation status of largetooth sawfish, particularly in a region isolated from other persisting populations that potentially harbours vital genetic diversity. Furthermore, safeguarding sawfish contributes to the implementation of national instruments like the National Action Plans for Sharks in both countries. Neglecting these threats could perpetuate sawfish capture and mortality in a region where local populations are already severely depleted, elevating the risk of regional extinction. Prioritizing sawfish conservation is imperative to prevent further decline and preserve their ecological importance.

Synchrony and Stability in Trophic Metacommunities: When Top Predators Navigate in a Heterogeneous World

Ecosystem stability strongly depends on spatial aspects since localized perturbations spread across an entire region through species dispersal. Assessing the synchrony of the response of connected populations is fundamental to understand stability at different scales because if populations fluctuate asynchronously, the risk of their simultaneous extinction is low, thus reducing the species' regional extinction risk. Here, we consider a metacommunity model consisting of two food chains connected by dispersal and we review the various mechanisms governing the transmission of small perturbations affecting populations in the vicinity of equilibrium. First, we describe how perturbations propagate vertically (i.e., within food chains through trophic interactions) and horizontally (i.e., between food chains through dispersal) in metacommunities. Then, we discuss the mechanisms susceptible to alter synchrony patterns such as density-depend dispersal or spatial heterogeneity. Density-dependent dispersal, which is the influence of prey or predator abundance on dispersal, has a major impact because the species with the highest coefficient of variation of biomass governs the dispersal rate of the dispersing species and determines the synchrony of its populations, thus bypassing the classic vertical transmission of perturbations. Spatial heterogeneity, which is a disparity between patches of the attack rate of predators on prey in our model, alters the vertical transmission of perturbations in each patch, thus making synchrony dependent on which patch is perturbed. Finally, by combining our understanding of the impact of each of these mechanisms on synchrony, we are able to full explain the response of realistic metacommunities such as the model developed by Rooney et al. (2006). By disentangling the main mechanisms governing synchrony, our metacommunity model provides a broad insight into the consequences of spacial aspects on food web stability.

The contribution of alternative habitats for conservation of plant species associated with threatened semi‐natural grasslands

Abstract Conservation of species associated with semi‐natural grasslands, a threatened habitat, is dependent on their ability to disperse between the few and fragmented patches remaining in the landscape. To maintain metapopulations dynamics and reduce the risk of regional extinction, it is essential to know whether other, more widespread, habitats can act as alternative habitat for the biodiversity associated with threatened habitats. Here, we study how four widespread habitat types in boreal landscapes—forest, permanent grassland, abandoned grassland and road verge—can contribute to the conservation of plant species found in semi‐natural grasslands which is a species‐rich ecosystem important for plant and pollinator diversity that has experienced extensive reduction, fragmentation and isolation. We compare richness of all vascular plants, insect‐pollinated plants and semi‐natural grassland specialists among habitat types in two regions is Norway where semi‐natural grasslands are few and fragmented. Based on overlap in community composition and local species richness, road verges were the most promising alternative habitat for both insect‐pollinated plants and semi‐natural grasslands specialists. Several habitat specialist species were, however, only found in semi‐natural grasslands and, for these species, no other habitat can be considered suitable as alternative habitat. Our results highlight that a holistic management perspective is needed to maintain biodiversity associated with semi‐natural grasslands. Thus, both the protection of remaining patches of the primary, threatened habitats as well as management of widespread, alternative habitats in the landscape should be prioritized.

Drivers and spatial patterns of population synchrony of fish species in a floodplain

Abstract Spatial synchrony is the correlation between the temporal dynamics of local populations. This pattern may be driven by spatially correlated environmental variation (i.e., Moran effect), dispersal and trophic interactions. Investigating geographic patterns of synchrony can help disentangle the relative importance of these drivers. Using fish abundance data from long‐term ecological research (17 years) in the Upper Paraná River floodplain, we studied the relative roles of dispersal distance, density dependence differences, and environmental synchrony in determining spatial synchrony of the most common species in this floodplain. We also investigated the geography of spatial synchrony by estimating modularity and site‐level contributions to synchrony and anti‐synchrony networks. We found positive spatial synchrony for most species, but levels were relatively low. For most species, our explanatory matrices were poorly related to spatial synchrony. We detected modular structures in some species networks, which reflected complex spatial patterns in synchrony. We also detected sites with high importance to spatial synchrony patterns that could be managed to increase metapopulation stability. The variable levels of spatial synchrony for fish species in the Upper Paraná River floodplain implies the need to monitor several sites to understand their dynamics in this region. Also, some migratory species of high importance to regional fisheries, such as Prochilodus lineatus, may deserve special monitoring attention due to the increased regional extinction risk associated with their high levels of spatial synchrony. Finally, we speculate that hydrological manipulation from upstream reservoirs should consider the timing of water releases to avoid spatially correlated population declines.

Predator avoidance and foraging for food shape synchrony and response to perturbations in trophic metacommunities

The response of species to perturbations strongly depends on spatial aspects in populations connected by dispersal. Asynchronous fluctuations in biomass among populations lower the risk of simultaneous local extinctions and thus reduce the regional extinction risk. However, dispersal is often seen as passive diffusion that balances species abundance between distant patches, whereas ecological constraints, such as predator avoidance or foraging for food, trigger the movement of individuals. Here, we propose a model in which dispersal rates depend on the abundance of the species interacting with the dispersing species (e.g., prey or predators) to determine how density-dependent dispersal shapes spatial synchrony in trophic metacommunities in response to stochastic perturbations. Thus, unlike those with passive dispersal, this model with density-dependent dispersal bypasses the classic vertical transmission of perturbations due to trophic interactions and deeply alters synchrony patterns. We show that the species with the highest coefficient of variation of biomass governs the dispersal rate of the dispersing species and determines the synchrony of its populations. In addition, we show that this mechanism can be modulated by the relative impact of each species on the growth rate of the dispersing species. Species affected by several constraints disperse to mitigate the strongest constraints (e.g., predation), which does not necessarily experience the highest variations due to perturbations. Our approach can disentangle the joint effects of several factors implied in dispersal and provides a more accurate description of dispersal and its consequences on metacommunity dynamics.

Synchrony and Perturbation Transmission in Trophic Metacommunities

AbstractIn a world where natural habitats are ever more fragmented, the dynamics of metacommunities are essential to properly understand species responses to perturbations. If species' populations fluctuate asynchronously, the risk of their simultaneous extinction is low, thus reducing the species' regional extinction risk. However, identifying synchronizing or desynchronizing mechanisms in systems containing several species and when perturbations affect multiple species is challenging. We propose a metacommunity model consisting of two food chains connected by dispersal to study the transmission of small perturbations affecting populations in the vicinity of an equilibrium. In spite of the complex responses produced by such a system, two elements enable us to understand the key processes that rule the synchrony between populations: (1) knowing which species have the strongest response to perturbations and (2) the relative importance of dispersal processes compared with local dynamics for each species. We show that perturbing a species in one patch can lead to asynchrony between patches if the perturbed species is not the most affected by dispersal. The synchrony patterns of rare species are the most sensitive to the relative strength of dispersal to demographic processes, thus making biomass distribution critical to understanding the response of trophic metacommunities to perturbations. We further partition the effect of each perturbation on species synchrony when perturbations affect multiple trophic levels. Our approach allows disentangling and predicting the responses of simple trophic metacommunities to perturbations, thus providing a theoretical foundation for future studies considering more complex spatial ecological systems.

Why do bugs perish? Range size and local vulnerability traits as surrogates of Odonata extinction risk.

Despite claims of an insect decline worldwide, our understanding of extinction risk in insects is incomplete. Using bionomic data of all odonate (603 dragonflies and damselflies) North American species, we assessed (i) regional extinction risk and whether this is related to local extirpation; (ii) whether these two patterns are similar altitudinally and latitudinally; and (iii) the areas of conservation concern. We used geographic range size as a predictor of regional extinction risk and body size, thermal limits and habitat association as predictors of local extirpation. We found that (i) greater regional extinction risk is related to narrow thermal limits, lotic habitat use and large body size (this in damselflies but not dragonflies); (ii) southern species are more climate tolerant but with more limited geographic range size than northern species; and (iii) two priority areas for odonate conservation are the cold temperate to sub-boreal northeastern USA and the transversal neo-volcanic system. Our approach can be used to estimate insect extinction risk as it compensates for the lack of abundance data.

Ash dieback risks an extinction cascade

Large-scale decline in populations of European ash (Fraxinus excelsior) are occurring throughout Europe due to the invasive fungus Hymenoscyphus fraxineus. This has grave ecological implications not only for ash trees, but also for the biodiversity supported by, and in some cases solely dependent on ash. Here we used data on the tree-species associations of biodiversity in Sweden, to predict extinction risks for ash-associated organisms, and the potential for combinations of other tree species to sustain ash-associated biodiversity. Of the 483 ash-associated species identified, 11% are exclusive to ash, and a further 23% prefer mainly ash. Notably, many ash-associated species are shared with wych elm (Ulmus glabra) which is similarly threatened by an invasive fungus. Considering the level of host association and the species' conservation status, 115 species were deemed at high risk of regional extinction. Using a mathematical optimization model we found that up to nine additional tree species would be needed to sustain all non-obligate ash dependent/preferring species in the absence of ash and elm. We discuss mitigation and adaption options to reduce the potential for an extinction cascade and conserve ash-associated biodiversity, but all pose unique challenges.

Spatial Scales of Population Synchrony in Predator-Prey Systems

Many species show synchronous fluctuations in population size over large geographical areas, which are likely to increase their regional extinction risk. Here we examine how the degree of spatial synchrony in population dynamics is affected by trophic interactions using a two-species predator-prey model with spatially correlated environmental noise. We show that the predator has a larger spatial scale of population synchrony than the prey if the population fluctuations of both species are mainly determined by the direct effect of stochastic environmental variations in the prey. This result implies that in ecosystems regulated from the bottom up, the spatial scale of synchrony of the predator population increases beyond the scale of the spatial autocorrelation in the environmental noise and in the prey fluctuations. Harvesting the prey increases the spatial scale of population synchrony of the predator, while harvesting the predator reduces the spatial scale of the population fluctuations of its prey. Hence, the development of sustainable harvesting strategies should also consider the impact on unharvested species at other trophic levels as well as human perturbations of ecosystems, whether the result of exploitation or an effect on dispersal processes, as they can affect food web structures and trophic interactions over large geographical areas.

Conserving Black Grouse Lyrurus tetrix in southern Scotland: evidence for the need to retain large contiguous moorland habitat within a forest-moorland landscape

ABSTRACTCapsuleBlack Grouse Lyrurus tetrix in southern Scotland are in severe decline, with remaining birds associated with large contiguous patches of moorland.AimsTo inform Black Grouse conservation programmes in southern Scotland we quantified recent trends in numbers, assessed habitat composition within lek ranges and evaluated the size of suitable habitat patches.MethodsWe explored trends in numbers of males at 121 leks surveyed between 1989 and 2018 in southwest and southeast Scotland. Wider surveys of males attending leks between 2006–12 were used to measure habitat composition within lek ranges and to compare with that in the study areas. Numbers of males at leks were considered in relation to habitat types and moorland management categories. Occupancy of moorland habitat patches was explored in relation to their size, connectivity and gamekeeping activity.ResultsAbundance at a sample of 121 leks surveyed between 1989–99 and 2017–18 fell from 70 males to zero in the southwest and from 340 to 44 in the southeast, with 82% of leks no longer occupied. Retained leks had more acid and rough grassland (53%) and less conifer cover (6%) within a 1 km radius than extinct leks (32% and 29%) and declines were similar across gamekeeping activity levels. Wider surveys in 2006–12 found acid and rough grassland, and dwarf shrub heath and bog to be the two preferred habitats within lek ranges. Leks were attended by twice as many males where driven Red Grouse Lagopus lagopus scotica shooting was practised. Occupied moorland habitat patches were 26 times larger than unoccupied patches.ConclusionBlack Grouse in southern Scotland are declining across all habitats. Moorland provides important habitat for remaining birds. With government targets to plant more woodland, remaining moorland habitat patches are likely to become more fragmented making them less able to support sustainable connected populations, which may exacerbate declines and enhance risk of regional extinction.

강원도 인구변화와 지역소멸 위험

본 연구는 강원도 인구변화 추이를 검토하고, 이를 기초로 지역소멸 가능성을 논의하는데 목적이 있으며 장래인구추계를 기초로 미래의 지역소멸 가능성을 검토하였다. 장래인구 추계에서 가장 뚜렷하게 나타나는 부문은 고령인구 구성비의 증가이다. 강원도의 고령인구 2015년 16.7%에서 2035년 35.6%로 크게 증가할 것으로 예상되며, 특히 2035년 횡성군과 양양군은 각각 47.5%, 47.1% 등에 이를 것으로 전망된다. 시군별 지역소멸 가능성에 대한 연구 결과 2015년 현재 7개 시 지역은 소멸위험 상태에서 벗어나 있으며, 군 지역에서는 8개 지역이 이미 소멸위험 상태에 처하고 있는 것으로 나타났다. 그러나 2035년에 이르면 이러한 상황이 크게 변해 강원도 18개 시군 모두가 소멸위험에 처할 것으로 전망된다. 인구감소와 고령화는 이제 일부 지역만의 문제가 아니라 강원 지역 전체의 문제로 다가오고 있는 것이다. 이러한 전망은 지방소멸의 문제를 보다 진지하게 고민하고 대비해야 함을 보여주는 결과이다.

Ignoring spatial heterogeneity in social conditions overestimates extinction risk of aquatic macrophytes

AbstractAimAbandoned lands are expanding globally due to depopulation in rural areas; biodiversity is declining due to the cessation of traditional management practices. However, the awareness of abandonment as a serious threat is still limited. Knowledge of the influence of the responsible factors on the assessment of regional extinction risk of species due to abandonment is sparse although it is indispensable for conservation decision‐making. This study aimed to clarify the influence of the heterogeneity in abandonment risk and interspecies differences in sensitivity to abandonment on regional species extinction risk and to identify the attributes of the species whose extinction risk is prone to be assessed inaccurately by ignoring the abandonment risk.LocationAwaji Island, Hyogo, Western Japan.MethodsWe assessed the extinction risk of 64 species of macrophytes under four scenarios: 2 × 2 combinations whether to incorporate interspecies differences in sensitivity to abandonment and the abandonment risk, respectively.ResultsIgnoring the abandonment risk overestimated the extinction risk of most species by 10%, whereas ignoring interspecies differences in sensitivity did not significantly affect the extinction risk. Ignoring the abandonment risk overestimated the extinction risk of emergent plants by 12%, whereas it underestimated that of free‐floating plants or threatened plants by 5%. Spatial bias in abandonment risk markedly reduced the correlation between the extinction risk and the frequency of species occurrence.Main conclusionsThe abandonment risk was more effective in accurately assessing the extinction risk due to abandonment than interspecies differences in sensitivity. Extinction risk of emergent, free‐floating or threatened species were assessed inaccurately by ignoring the abandonment risk. Focusing only on the area of occurrence or the extent of occurrence of a species as a surrogate for its extinction risk is likely to produce inaccurate assessments, and thus should be avoided.

Habitat loss exacerbates regional extinction risk of the keystone semiarid shrub Ziziphus lotus through collapsing the seed dispersal service by foxes (Vulpes vulpes)

Habitat loss and landscape degradation affect animal-mediated seed dispersal, often collapsing the regeneration of endangered plant species and habitats in anthropogenic landscapes. We first compared the role of red fox and other vertebrates as seed disperser for the keystone scrub Ziziphus lotus. Because it turned out that foxes are the major Z. lotus dispersers, we investigated how fox activity and dispersal service relate to habitat loss and landscape alteration in the threatened Ziziphus semiarid scrublands, a priority habitat for conservation in Europe. Considering its opportunistic behavior, we hypothesized that landscape features should affect moderately fox abundance, while influence in a large extent its dispersal service. Accordingly, we predicted that a substantial decline in Ziziphus fruit consumption rather than in disperser activity would be responsible for seed dispersal collapse under severe habitat loss. We evaluated fox activity and dispersal service in 17 populations of Z. lotus spread through the range of its habitat in Spain and found within landscapes with different land-use intensity. We certified the collapse of the dispersal service by fox under severe habitat loss and confirmed that fox activity was less affected by habitat loss or landscape alteration than consumption of Ziziphus fruits. Consequently, the decline of consumption of Ziziphus fruits under severe habitat loss triggers the collapse of its seed dispersal. Results suggest that without increase of the remnant areas other managements may not suffice to achieve seed dispersal and habitat restoring. Dispersal service and natural regeneration in many Ziziphus habitat remnants will possibly cease in the future if habitat loss continues.

Genome-environment association study suggests local adaptation to climate at the regional scale in Fagus sylvatica.

The evolutionary potential of long-lived species, such as forest trees, is fundamental for their local persistence under climate change (CC). Genome-environment association (GEA) analyses reveal if species in heterogeneous environments at the regional scale are under differential selection resulting in populations with potential preadaptation to CC within this area. In 79 natural Fagus sylvatica populations, neutral genetic patterns were characterized using 12 simple sequence repeat (SSR) markers, and genomic variation (144 single nucleotide polymorphisms (SNPs) out of 52 candidate genes) was related to 87 environmental predictors in the latent factor mixed model, logistic regressions and isolation by distance/environmental (IBD/IBE) tests. SSR diversity revealed relatedness at up to 150m intertree distance but an absence of large-scale spatial genetic structure and IBE. In the GEA analyses, 16 SNPs in 10 genes responded to one or several environmental predictors and IBE, corrected for IBD, was confirmed. The GEA often reflected the proposed gene functions, including indications for adaptation to water availability and temperature. Genomic divergence and the lack of large-scale neutral genetic patterns suggest that gene flow allows the spread of advantageous alleles in adaptive genes. Thereby, adaptation processes are likely to take place in species occurring in heterogeneous environments, which might reduce their regional extinction risk under CC.

Simulated shifts in trophic niche breadth modulate range loss of alpine butterflies under climate change

Species currently track suitable abiotic and biotic conditions under ongoing climate change. Adjustments of trophic interactions may provide a mechanism for population persistence, an option that is rarely included in model projections. Here, we model the future distribution, of butterflies in the western Alps of Switzerland under climate change, simulating potential diet expansion resulting from adaptive behavior or new host opportunities. We projected the distribution of 60 butterfly and 298 plant species with species distribution models (SDMs) under three climate change scenarios. From known host plants, we allowed a potential diet expansion based on phylogenetic constraints. We assessed whether diet expansion could reduce the rate of expected regional species extinction under climate change. We found that the risk of species extinctions decreased with a concave upward decreasing shape when expanding the host plant range. A diet expansion to even a few phylogenetically closely related host plants would significantly decrease extinction rates. Yet, even when considering expansion toward all plant species available in the study area, the overall regional extinction risk would remain high. Ecological or evolutionary shifts to new host plants may attenuate extinction risk, but the severe decline of suitable abiotic conditions is still expected to drive many species to local extinction.

‘High‐co‐occurrence genera’: weak but consistent relationships with global richness, niche partitioning, hybridization and decline

AbstractAimMany biologists explain the global richness of lineages and local co‐occurrence of lineage members by distinct processes: speciation/extinction versus ecological interactions. Moreover, allopatric distribution, rarity and local competition limit local co‐occurrence of species even within species‐rich lineages. However, whether and why the global richness of lineages relates to local co‐occurrence of lineage members has not been tested. We study angiosperms, and hypothesize that in globally species‐rich genera species frequently encounter congeners locally, reflecting (1) random sampling of species pools into local communities and (2) processes of global species production and local survival such as hybridization, niche filling and a reduced risk of extinction.LocationNetherlands, South Africa, world‐wide.MethodsAnalysing more than 350,000 plots we quantify per species the observed number of co‐occurring congeners as well as the null expectation based on random sampling from species pools. From the literature we quantify the global species richness of genera, and abiotic niche positions and breadths, hybrid status and regional species declines.ResultsIn some genera species frequently encounter congeners locally, while in others congeners are rarely encountered. This is independent of the total number of species encountered, and is consistent between the Netherlands and South Africa. ‘High‐co‐occurrence genera’ are particularly species rich across the globe, consistently so in most families and even after controlling for niche positions, age and regional richness of genera. Species in high‐co‐occurrence genera tend to occupy niches that are large and close to congeners’ niches. These species are more often hybrids and rarely decline. Relationships explain little variance (< 10%) but are stronger than expected from random sampling of species rich pools.Main conclusionsLocal co‐occurrence and global species richness are largely independent, but not entirely so, reflecting random sampling of pools into communities, niche partitioning, hybridization and the reduced risk of regional extinction in high‐co‐occurrence genera. Increased extinction risk in low‐co‐occurrence genera implies a proportionately high loss of lineages and their evolutionary heritage from local communities.

Effects of landscape and patch-level attributes on regional population persistence

Species responses are influenced by processes operating at multiple scales, yet many conservation studies and management actions are focused on a single scale. Although landscape-level habitat conditions (i.e., habitat amount, fragmentation and landscape quality) are likely to drive the regional persistence of spatially structured populations, patch-level factors (i.e., patch size, isolation, and quality) may also be important. To determine the spatial scales at which habitat factors influence the regional persistence of endangered Ord's kangaroo rats (Dipodomys ordii) in Alberta, Canada, we simulated population dynamics under a range of habitat conditions. Using a spatially-explicit population model, we removed groups of habitat patches based on their characteristics and measured the resulting time to extinction. We used proportional hazards models to rank the influence of landscape and interacting patch-level variables. Landscape quality was the most influential variable followed by patch quality, with both outweighing landscape- and patch-level measures of habitat quantity and fragmentation/proximity. Although habitat conservation and restoration priorities for this population should be in maximizing the overall quality of the landscape, population persistence depends on how this goal is achieved. Patch quality exerted a significant influence on regional persistence, with the removal of low quality road margin patches (sinks) reducing the risk of regional extinction. Strategies for maximizing overall landscape quality that omit patch-level considerations may produce suboptimal or detrimental results for regional population persistence, particularly where complex local population dynamics (e.g., source-sink dynamics) exist. This study contributes to a growing body literature that suggests that the prediction of species responses and future conservation actions may best be assessed with a multi-scale approach that considers habitat quality and that the success of conservation actions may depend on assessing the influences of habitat factors at multiple scales.