A climate-associated multispecies cryptic cline in the northwest Atlantic

Context Extrapolation of knowledge for threatened taxa between parts of their range that are disconnected and/or ecologically diverse can result in significant sources of error that undermine the effectiveness of conservation efforts. Aims We investigated the risks associated with extrapolation of ecological information across environmental gradients, using the quokka (Setonix brachyurus) as a case study. Information documented in the northern part of its range is currently used to manage this species across its range in south-western Australia. We examined the suitability of this approach by developing a habitat suitability model (HSM) for the quokka in the southernmost areas of its range and comparing this with existing knowledge for the species. Methods We surveyed 327 sites, representative of a range of ecotypes, for presence/absence of quokkas. Occupancy models were applied to select a subset of habitat variables that best predicted occupancy patterns. Key results Occupancy patterns were influenced by complex vegetation structure, low levels of woody debris and habitat patchiness. HSMs developed for quokkas in the north could not predict occupancy patterns in the south. Significant fragmentation of subpopulations was observed due to patchiness in the availability of suitable habitat. Conclusions The choice of predictor variables in HSMs that are not transferrable between regions could contribute to inappropriate management of habitat for quokkas and an increased risk of local extinctions. In addition, failure to consider processes that affect preferred habitat variables could contribute to the segregation of habitat patches and intervening distances that are too great for successful dispersal, immigration and recolonisation processes. Implications The extrapolation of HSMs between geographical areas can increase the risk of outcomes that are detrimental to the conservation of threatened species. Where such extrapolation is necessary, actions guided by the HSMs should be implemented in a management framework that can detect adverse effects, allow for inclusion of new ecological information and explicitly consider the limitations and assumptions of this approach. In addition, perceptions of habitat fragmentation need to include processes such as fire regimes and feral animals that affect the availability and connectivity of habitat and have the potential to adversely affect population viability.

AimThe objective of this study is to estimate the current potential geographic distribution of Plebeia flavocincta and to evaluate the influence of climate on the dynamics of suitable habitat availability in the past and in the future.LocationNortheast region of Brazil and dry forest areas.MethodsThe habitat suitability modeling was based on two algorithms, two global circulation models, and six different scenarios. We used this tool to estimate the areas of occurrence in the past (Last Interglacial and Last Glacial Maximum), in the present, and in the future (years 2050 and 2070).ResultsAccording to the models, P. flavocincta had great dynamics in the availability of suitable habitats with periods of retraction and expansion of these areas in the past. Our results suggest that this taxon may benefit in terms of climate suitability gain in Northeast Brazil in the future. In addition, we identified high‐altitude areas and the eastern coast as climatically stable.ConclusionThe information provided can be used by decision makers to support actions toward protecting and sustainably managing this taxon. Protection measures for this taxon are particularly important because this insect contributes to the local flora and, although our results indicate that the climate may favor this taxon, other factors can negatively affect it, such as high levels of habitat loss due to anthropogenic activities.

Summary Males of many bird species match song with neighbours during territorial interactions. Although bird vocal mimicry has received much attention, the relationships between song variation and ecological factors such as landscape geometry and habitat fragmentation are still poorly known, and most previous research has been limited to one or a few populations of a species. In this study we analysed the spatial patterns and ecological determinants of song matching in Dupont's lark Chersophilus duponti, a rare and specialized steppe passerine. By recording bird songs from 21 Spanish and Moroccan localities, we analysed the effect of habitat fragmentation and the availability of suitable steppe habitat on the patterns of song matching in Dupont's lark, controlling for other potential determinants such as period in the breeding season, intensity of competition, geographical location and spatial distribution of individuals. Both song‐type sharing (match of song types in the repertoire) and spectrotemporal matching (convergence in the acoustic features of the same song type) were greater between counter‐singing neighbours than between non‐neighbours, and spatial autocorrelation (similarities between singing individuals) only occurred at short distances. The study localities differed in the amount of overall acoustic matching between individuals, seemingly as a consequence of local differences in the intensity of male competition and in the availability of suitable habitat. The levels of song‐type sharing between non‐neighbours tended to increase and those among neighbours to decrease with the increase of steppeland availability. Moreover, the existing differences in sharing between neighbours and non‐neighbours were significantly affected by the presence of elements of fragmentation in the steppe. In fragmented habitats, song sharing among neighbours was enhanced, possibly because of harsher competition for limited resources; conversely, sharing among non‐neighbours dropped, probably because of the lack of interactions among individuals isolated by habitat barriers. Synthesis and applications. Anthropogenic habitat barriers could alter bird perception of the spatial distribution of rivals over distance, leading to a contraction of the spatial range of the individual acoustic niche. We suggest that communication systems of habitat‐sensitive species might be used as a behavioural indicator of anthropogenic environmental deterioration. Because of their rapidly evolving cultural nature, bird vocalizations might become an early warning system detecting the effects of fragmentation over relatively short times and before other indicators (such as genetic markers) show any change.

Populations of Loggerhead Shrikes (Lanius ludovicianus) across North America have been declining, and factors responsible for this decline remain unclear. Few studies have focused on the availability and use of wintering habitat. Our objectives were to ascertain the size and characteristics of Loggerhead Shrike territories, and examine the hunting behavior of shrikes during the non-breeding season. We observed 1,372 hunting attempts by 19 shrikes; arthropods (65.3%) and other invertebrates (23.3%) were the most common prey. Characteristics of habitat at used and randomly selected, apparently unused isolated and continuous perch sites differed (P = 0.023 and P = 0.021, respectively). Used perches had less grass cover, more bare ground, and denser, shorter vegetation. We found no difference between characteristics of occupied and unoccupied areas (P = 0.34). Non-breeding territories in our study were larger (mean = 85 ha) than those reported for shrikes during the breeding season. The availability of suitable winter habitat does not appear to be limiting Loggerhead Shrike populations in Kentucky. However, most Loggerhead Shrikes winter south of Kentucky where densities are higher, and it is possible that availability of suitable habitat might be a limiting factor in some areas.

Summary 1. Spatial distribution, abundance and habitat requirements of Ragadia makuta (Satyrinae) were studied in Sabah (Borneo) in 1997, in unlogged forest and forest that had been selectively logged 8–9 years ago. 2. Measurement of vegetation structure showed that unlogged forest had significantly larger trees and greater canopy cover than logged forest. A principal components analysis extracted two factors related to forest density and tree size that were also significantly higher in unlogged forest. However, there was significant spatial heterogeneity in vegetation structure within logged forest. 3. In undisturbed forest, a logistic regression model identified suitable habitat for R. makuta as areas of less dense forest close to streams. There were no differences between logged and unlogged habitats in spatial distribution and abundance of R. makuta. Availability of suitable habitat and habitat requirements of butterflies also did not differ between habitats. There was, however, significant heterogeneity in butterfly abundance within logged forest, corresponding with availability of suitable habitat. 4. Fieldwork in 1997 coincided with a severe drought on Borneo, and butterfly spatial distribution and abundance were significantly reduced compared with a year of more normal rainfall (1996); populations in 1997 contracted to areas around streams and to areas with high cover of host‐plant. 5. Selectively logged areas can be highly heterogeneous in relation to levels of disturbance. Quantifying the effects of selective logging on forest structure and the availability of suitable habitat was crucial to understanding the responses of R. makuta to habitat disturbance.

Identifying genetically differentiated populations is important for successful species conservation and management, and collecting baseline population genomic data can allow us to quantify impacts from environmental changes and anthropogenic stressors. Unlike most auks, which breed in a few large colonies, black guillemots (Cepphus grylle) are dispersed breeders, whose range spans diverse environmental conditions, from polar to temperate waters. They are harvested in some northern regions and can be an important indicator of coastal ecosystem health, but knowledge of their population genetic structure is limited. We used double-digest restriction-site associated DNA sequencing to determine the extent to which regional samples of black guillemots (n = 172) in the Arctic and North Atlantic oceans differ at presumptively neutral markers. Population genetic analyses identified three genetic clusters: (1) Northwest Atlantic: Gulf of Maine, Gulf of St. Lawrence, and East Canadian Shelf (Nova Scotia); (2) Arctic: Baffin Bay, Hudson Bay, Davis Strait, Labrador Shelf, East Canadian Shelf (Newfoundland), and Fram Strait (Svalbard); and (3) Northeast Atlantic: Denmark Strait (Iceland) and the Baltic Sea. Regions of secondary contact appear to exist in northern Baffin Bay and the Northwest Atlantic. Possible reasons for this pattern of genetic structure include historical isolation in multiple glacial refugia during the Pleistocene and contemporary barriers to gene flow. Comparison of several potential historical scenarios provided strongest support for isolation of black guillemots in two glacial refugia in the Northwest and Northeast Atlantic, followed by range expansion and secondary contact in the Arctic since recession of the glaciers. Our results suggest that management of black guillemots will require an internationally coordinated approach to conserve the genomic variation within this species.

To offset declines in commercial landings of the softshell clam, Mya arenaria, resource managers are engaged in extensive stocking of seed clams throughout its range in the northwest Atlantic. Because a mixture of native and introduced stocks can disrupt locally adapted genotypes, we investigated genetic structure in M. arenaria populations across its current distribution to test for patterns of regional differentiation. We sequenced mitochondrial cytochrome oxidase I for a total of 212 individuals from 12 sites in the northwest Atlantic (NW Atlantic), as well as two introduced sites, the northeast Pacific (NE Pacific), and the North Sea Europe (NS Europe). Populations exhibited extremely low genetic variation, with one haplotype dominating (65–100%) at all sites sampled. Despite being introduced in the last 150–400 years, both NE Pacific and NS Europe populations had higher diversity measures than those in the NW Atlantic and both contained private haplotypes at frequencies of 10–27% consistent with their geographic isolation. While significant genetic structure (F ST = 0.159, P < 0.001) was observed between NW Atlantic and NS Europe, there was no evidence for genetic structure across the pronounced environmental clines of the NW Atlantic. Reduced genetic diversity in mtDNA combined with previous studies reporting reduced genetic diversity in nuclear markers strongly suggests a recent population expansion in the NW Atlantic, a pattern that may result from the retreat of ice sheets during Pleistocene glacial periods. Lack of genetic diversity and regional genetic differentiation suggests that present management strategies for the commercially important softshell clam are unlikely to have a significant impact on the regional distribution of genetic variation, although the possibility of disrupting locally adapted stocks cannot be excluded.

We captured 6 Florida panthers (Felis concolor coryi) in southern Florida and radiolocated them 1,630 times from February 1981 through August 1983. Mean home area for 4 males and 2 females was 435 ? 231 (SE) km2 and 202 ? 141 km2, respectively. Mixed swamp forests and hammock forests were used more than expected based on the availability of these habitats within the panthers' home areas. Based on the availability of mixed swamp forests and hammock forests, we estimate that south Florida can support 30-40 panthers. The major factor limiting the panther population in south Florida appears to be availability of suitable habitat. J. WILDL. MANAGE. 52(4):660-663 In October 1976 the Florida Game and Fresh Water Fish Commission (GFC) initiated a study of the Florida panther to determine if a viable population of panthers remained in Florida. At least 1 population was located in the Fakahatchee Strand-Big Cypress Swamp-Everglades National Park region of southern Florida (Belden 1978). Our objective was to identify habitat necessary for the continued survival of the population of panthers in southern Florida. We acknowledge T. H. Logan and T. C. Hines for constructive criticism, guidance, and support. We also appreciate O. L. Bass, D. K. Jansen, J. McGrady, D. B. Pylant, J. G. Quinn, and J. S. Sanders for assistance with field work; G. L. Evink, W. H. Kuyper, J. Becker, R. Whitehead, R. D. Hallman, E. G. Phillips, J. D. Edrington III, and C. E. Gardner of the Florida Department of Transportation for habitat mapping and analyses; and G. Hensler, C. Moore, This content downloaded from 157.55.39.35 on Thu, 01 Sep 2016 04:39:07 UTC All use subject to http://about.jstor.org/terms J. Wildl. Manage. 52(4):1988 PANTHER HABITAT * Belden et al. 661 and G. R. Morgan for statistical assistance. Primary funding was provided by the GFC and by federal grant-in-aid funds administered through the U.S. Fish and Wildlife Service under Section 6 of the Endangered Species Act of 1973 (PL No. 93-205).

Non-native conifers constitute a significant threat to the ecology and biodiversity of many of New Zealand’s native ecosystems and species. From the top down, the potential distributions of non-native conifer species are governed by climate suitability, which alongside variables such as the availability of suitable habitats and a source of propagules determines whether an area of land will be susceptible to invasion by a given species.

Some species cope with, and survive in, urban areas better than others.From a conservation viewpoint it is important to understand why some species arerare or are excluded in the urban landscape, in order that we might take actionto conserve and restore species. Two ecological factors that might explain thedistribution and abundance of butterfly species in the urban landscape aredispersal ability and the availability of suitable habitat. The influence ofthese factors was assessed by examining the distribution and genetic structureof four grassland butterfly species in the West Midlands conurbation, UK. Thefour species differ in their distribution and abundance, mobility and habitatspecificity. No significant fit to the isolation-by-distance model was found forany of the study species at this spatial scale. MeanF ST values revealed a non-significant level ofpopulation structuring for two species, Pieris napi (L.)and Maniola jurtina (L.), but moderate and significantpopulation differentiation for Pyronia tithonus (L.) andCoenonympha pamphilus (L.). Results suggest that thesespecies are limited more by the availability of suitable habitat than by theirability to move among habitat patches. Conservation strategies for thesegrassland species should initially focus on the creation and appropriatemanagement of suitable habitat. More sedentary species that have already beenexcluded from the conurbation may require a more complex strategy for theirsuccessful restoration.

Habitat availability and climate warming drive changes in the distribution of grassland grasshoppers

Range shifting is vital for species persistence, but there is little consensus on why individual species vary so greatly in the rates at which their ranges have shifted in response to recent climate warming. Here, using 40 years of distribution data for 291 species from 13 invertebrate taxa in Britain, we show that interactions between habitat availability and exposure to climate change at the range margins explain up to half of the variation in rates of range shift. Habitat generalists expanded faster than more specialised species, but this intrinsic trait explains less of the variation in range shifts than habitat availability, which additionally depends on extrinsic factors that may be rare or widespread at the range margin. Similarly, while climate change likely underlies polewards expansions, we find that more of the between-species variation is explained by differences in habitat availability than by changes in climatic suitability. A model that includes both habitat and climate, and their statistical interaction, explains the most variation in range shifts. We conclude that climate-change vulnerability assessments should focus as much on future habitat availability as on climate sensitivity and exposure, with the expectation that habitat restoration and protection will substantially improve species’ abilities to respond to uncertain future climates.

Climate change is anticipated to alter plant species distributions. Regional context, notably the spatial complexity of climatic gradients, may influence species migration potential. While high-elevation species may benefit from steep climate gradients in mountain regions, their persistence may be threatened by limited suitable habitat as land area decreases with elevation. To untangle these apparently contradictory predictions for mountainous regions, we evaluated the climatic suitability of four coniferous forest tree species of the western United States based on species distribution modeling (SDM) and examined changes in climatically suitable areas under predicted climate change. We used forest structural information relating to tree species dominance, productivity, and demography from an extensive forest inventory system to assess the strength of inferences made with a SDM approach. We found that tree species dominance, productivity, and recruitment were highest where climatic suitability (i.e., probability of species occurrence under certain climate conditions) was high, supporting the use of predicted climatic suitability in examining species risk to climate change. By predicting changes in climatic suitability over the next century, we found that climatic suitability will likely decline, both in areas currently occupied by each tree species and in nearby unoccupied areas to which species might migrate in the future. These trends were most dramatic for high elevation species. Climatic changes predicted over the next century will dramatically reduce climatically suitable areas for high-elevation tree species while a lower elevation species, Pinus ponderosa, will be well positioned to shift upslope across the region. Reductions in suitable area for high-elevation species imply that even unlimited migration would be insufficient to offset predicted habitat loss, underscoring the vulnerability of these high-elevation species to climatic changes.

The southern coastline of South America is a remarkable area to evaluate how Quaternary glacial processes impacted the demography of the near-shore marine biota. Here we present new phylogeographic analyses in the pulmonate Siphonaria lessonii across its distribution, from northern Chile in the Pacific to Uruguay in the Atlantic. Contrary to our expectations, populations from the southwestern Atlantic, an area that was less impacted by ice during glacial maxima, showed low genetic diversity and evidence of recent expansion, similar to the patterns recorded in this study across heavily ice-impacted areas in the Pacific Magellan margin. We propose that Atlantic and Pacific shallow marine hard-substrate benthic species were both affected during the Quaternary in South America, but by different processes. At higher latitudes of the southeast Pacific, ice-scouring drastically affected S. lessonii populations compared to non-glaciated areas along the Chile-Peru province where the species was resilient. In the southwest Atlantic, S. lessonii populations would have been dramatically impacted by the reduction of near-shore rocky habitat availability as a consequence of glacio-eustatic movements. The increase of gravelly and rocky shore substrates in the southwest Atlantic supports a hypothesis of glacial refugia from where the species recolonized lower latitudes across the Atlantic and Pacific margins. Our results suggest that current patterns of genetic diversity and structure in near-shore marine benthic species do not solely depend on the impact of Quaternary glacial ice expansions but also on the availability of suitable habitats and life-history traits, including developmental mode, bathymetry and the likelihood of dispersal by rafting.

Buccinum undatum (waved whelk) is a neogastropod with several small-scale commercial fisheries in Atlantic Canada. Whelks are vulnerable to overfishing, partly because they lack a pelagic larval phase. To date, no studies in the Northwest Atlantic have synthesized demographic and genetic data to explore the species’ biology at a fishery relevant scale. We quantified patterns of genetic structure in whelks within both the Northwest Atlantic Fisheries Organization subdivision 3Ps fishing zone and in the broader Northwest Atlantic, and estimated length at first maturity ( L50) of 3Ps whelks. Genetic structure estimates were low, indicating one genetic population within 3Ps, with subtle but significant differentiation across the Northwest Atlantic. L50 was 64.0 and 69.9 mm for males and females, respectively and above the regional minimum legal size of 63 mm. Our results suggest that separate regional management of Northwest Atlantic fisheries is appropriate. Within 3Ps, whelks are genetically well-mixed, but the implications for population persistence and management remain unknown. To safeguard the stock in the face of continued fishing, further assessments of demographic traits are warranted.