Proportion Of Suitable Habitat Research Articles

Impact of Climate Change on the Distribution of Three Rare Salamanders (Liua shihi, Pseudohynobius jinfo, and Tylototriton wenxianensis) in Chongqing, China, and Their Conservation Implications.

The Wushan Salamander (Liua shihi), Jinfo Salamander (Pseudohynobius jinfo), and Wenxian Knobby Salamander (Tylototriton wenxianensis) are rare national Class II protected wild animals in China. We performed MaxEnt modeling to predict and analyze the potential distribution and trends of these species in Chongqing under current and future climate conditions. Species distribution data were primarily obtained from field surveys, supplemented by museum collections and the existing literature. These efforts yielded 636 records, including 43 for P. jinfo, 23 for T. wenxianensis, and 570 for L. shihi. Duplicate records within the same 100 m × 100 m grid cell were removed using ENMTools, resulting in 10, 12, and 58 valid distribution points for P. jinfo, T. wenxianensis, and L. shihi, respectively. The optimization of feature class parameters (FC) and the regularization multiplier (RM) were applied using R package "ENMeval 2.0" to establish the optimal model with MaxEnt. The refined models were applied to simulate the suitable distribution areas for the three species. The results indicate that the current suitable habitat area for L. shihi accounted for 9.72% of the whole region of the Chongqing municipality. It is projected that, by 2050, the proportion of suitable habitat will increase to 12.54% but will decrease to 11.98% by 2070 and further decline to 8.80% by 2090. The current suitable habitat area for P. jinfo accounted for 1.08% of the whole region of the Chongqing municipality, which is expected to decrease to 0.31%% by 2050, 0.20% by 2070, and 0.07% by 2090. The current suitable habitat area for T. wenxianensis accounted for 0.81% of the whole region of the Chongqing municipality, which is anticipated to decrease to 0.37% by 2050, 0.21% by 2070, and 0.06% by 2090. Human disturbance, climate variables, and habitat characteristics are the primary factors influencing the distribution of three salamander species in Chongqing. The proximity to roads significantly impacts L. shihi, while climate conditions mainly affect P. jinfo, and the distance to water sources is crucial for T. wenxianensis. The following suggestions were made based on key variables identified for each species: (1) For L. shihi, it is imperative to minimize human disturbances and preserve areas without roads and the existing vegetation within nature reserves to ensure their continued existence. (2) For P. jinfo, the conservation of high-altitude habitats is of utmost importance, along with the reduction in disturbances caused by roads to maintain the species' ecological niche. (3) For T. wenxianensis, the protection of aquatic habitats is crucial. Additionally, efforts to mitigate the impacts of road construction and enhance public awareness are essential for the preservation of this species and the connectivity of its habitats.

Instream complexity increases habitat quality and growth for cutthroat trout in headwater streams

The extent and availability of suitable habitat is a fundamental factor limiting the abundance of natural populations. In many stream ecosystems, habitat degradation has reduced habitat quality by removing critical habitat features such as pools. We hypothesized that adding pool habitat to streams would increase habitat quality for salmonid fish and improve population productivity. In this study, we used instream structures to add pool habitat to four headwater streams and estimated changes to habitat quality for cutthroat trout ( Oncorhynchus clarkii) across two seasons using a bioenergetic model. Fish populations were monitored over 5 years to evaluate how treatments influenced fish abundance and growth. We found that the proportion of suitable habitat was higher in treatment sections and in artificially created pool habitats. Abundance of young-of-the-year trout was higher in treatment reaches in comparison to controls and the growth of trout across all size classes sampled was higher in treatment reaches. Our results indicate that increasing pool habitat improves habitat quality resulting in increased densities of cutthroat trout and higher fish growth.

Identifying human–brown bear conflict hotspots for prioritizing critical habitat and corridor conservation in southwestern Iran

AbstractMultiple studies have used species distribution models to identify human–wildlife conflict drivers. An important application of these models is spatial conflict resolution by accounting for habitat suitability and corridors. We used distribution and connectivity models to identify habitats and corridors for brown bear Ursus arctos in southwestern Iran with high risk of bear damages, and evaluated the effects of landscape composition and configuration on the predicted conflict hotspots. We used 154 locations of bear damage incidents along with a suit of predictors to develop risk models. To prepare predictive variables, we used brown bear occurrence data and a number of covariates to develop a suitability model. We then converted the suitability map into a resistance surface and used a connectivity model to predict corridors. Finally, the bear damages risk map, habitats and corridors were overlaid to prioritize conflict hotspots, corridors and habitats, and conflict‐prone corridors. Proportion of suitable habitats, distance to village, density of forest patches, conservation areas and corridor bottlenecks were the main predictors contributing to bear damages risk. A total of 38.73% of habitats, and 6.24% of corridors across the 124 000‐km2 study area were identified as areas with high risk of bear damages. The risk of bear damage was also spatially associated with forests fragmentation and patchiness of habitat. Our results highlight the importance of landscape configuration and corridors when investigating the spatial patterns of bear damages. Our findings showed how the combination of distribution models and connectivity analysis can guide carnivore conservation planning aiming at reducing the risk of carnivore‐inflicted damages.

A validation standard for area of habitat maps for terrestrial birds and mammals

Abstract. Area of habitat (AOH) is a deductive model which maps the distribution of suitable habitats at suitable altitudes for a species inside its broad geographical range. The AOH maps have been validated using presence-only data for small subsets of species for different taxonomic groups, but no standard validation method exists when absence data are not available. We develop a novel two-step validation protocol for AOH which includes first a model-based evaluation of model prevalence (i.e, the proportion of suitable habitat within a species' range), and second a validation using species point localities (presence-only) data. We applied the protocol to AOH maps of terrestrial birds and mammals. In the first step we built logistic regression models to predict expected model prevalence (the proportion of the range retained as AOH) as a function of each species' elevation range, mid-point of elevation range, number of habitats, realm and, for birds, seasonality. AOH maps with large differences between observed and predicted model prevalence were identified as outliers and used to identify a number of sources of systematic error which were then corrected when possible. For the corrected AOH, only 1.7 % of AOH maps for birds and 2.3 % of AOH maps for mammals were flagged as outliers in terms of the difference between their observed and predicted model prevalence. In the second step we calculated point prevalence, the proportion of point localities of a species falling in pixels coded as suitable in the AOH map. We used 48 336 141​​​​​​​ point localities for 4889 bird species and 107 061 point localities for 420 mammals. Where point prevalence exceeded model prevalence, the AOH was a better reflection of species' distribution than random selection. We also found that 4689 out of 4889 (95.9 %) AOH maps for birds, and 399 out of 420 (95.0 %) AOH maps for mammals were better than random. Possible reasons for the poor performance of a small proportion of AOH maps are discussed.

A Bocage Landscape Restricts the Gene Flow of Pest Vole Populations.

The population dynamics of most animal species inhabiting agro-ecosystems may be determined by landscape characteristics, with agricultural intensification and the reduction of natural habitats influencing dispersal and hence limiting gene flow. Increasing landscape complexity would thus benefit many endangered species by providing different ecological niches, but it could also lead to undesired effects in species that can act as crop pests and disease reservoirs. We tested the hypothesis that a highly variegated landscape influences patterns of genetic structure in agricultural pest voles. Ten populations of fossorial water vole, Arvicola scherman, located in a bocage landscape in Atlantic NW Spain were studied using DNA microsatellite markers and a graph-based model. The results showed a strong isolation-by-distance pattern with a significant genetic correlation at smaller geographic scales, while genetic differentiation at larger geographic scales indicated a hierarchical pattern of up to eight genetic clusters. A metapopulation-type structure was observed, immersed in a landscape with a low proportion of suitable habitats. Matrix scale rather than matrix heterogeneity per se may have an important effect upon gene flow, acting as a demographic sink. The identification of sub-populations, considered to be independent management units, allows the establishment of feasible population control efforts in this area. These insights support the use of agro-ecological tools aimed at recreating enclosed field systems when planning integrated managements for controlling patch-dependent species such as grassland voles.

Suitable Habitat Dynamics of Wintering Geese in a Large Floodplain Wetland: Insights from Flood Duration

The relationship between hydrological variation and the habitat use of waterbirds in wetland complexes is a significant field of ecological research. Quantification of the relationships between wetland hydrological attributes and waterbirds distribution is critical for the success of waterbird conservation. In this study, flood duration (FD) derived from synthetic aperture radar (SAR) imagery was combined with geese GPS tracking data to quantify the optimal FD thresholds for identifying geese habitats. Based on the thresholds, we defined the suitable habitats of wintering geese and investigated the difference in the spatial distribution pattern of habitat from 2018 to 2020 in Poyang Lake, China. We also considered the role of sub-lakes in habitat protection. The results showed that the area of suitable habitats for wintering geese decreased in both dry and wet years, and the range of optimal FD threshold was wider in normal years than in both dry and wet years. The proportion of suitable habitats per unit area was greater in the sub-lakes than in the whole Poyang Lake. We concluded that FD indices extracted from SAR data are valuable for reflecting the influence of the pattern of hydrological variation on waterbird distribution and for the protection and rational use of wetland ecosystems.

The effect of oil palm-dominated landscapes on the home range and distribution of a generalist species, the Asian water monitor.

The Asian water monitor lizard, Varanus salvator, is one of the largest predators in Southeast Asia which persists in human‐dominated landscapes and, as such, is a suitable model to understand the behavioral plasticity of generalists in anthropogenic landscapes. We used Local Convex Hull with adaptive algorithm to estimate the home range size of 14 GPS‐tagged individuals, followed by a MAXENT approach and community prey composition to understand the habitat preferences within the landscape. We estimated larger home ranges in forest than in oil palm plantations, as well as a larger diversity and abundance of mammals. Core home ranges were always linked to water bodies. However, the use of underproductive oil palm, freshwater swamp forest, and degraded forest by monitor lizards were higher than other kind of vegetation. This suitable habitat is proportionally larger in forest (73.7%) than in oil palm plantations (39.6%). Generalized estimation equation models showed that, while full home range size was negatively associated with the abundance of mammals, core areas depicted a positive association with mammal abundance, as well as with the proportion of suitable habitat within the home range. Besides having smaller home ranges in oil palm plantations, our findings suggest that limited suitable habitat availability forces the Asian water monitor lizard's population to establish only one or very few core areas. Contrastingly, under the protection of forest, they have more core areas, widely dispersed within larger home ranges. We conclude that regardless the plasticity of the species, human‐dominated landscapes are altering natural patterns of home range establishment in the monitor lizard's population, creating a potential ecological trap where conditions may not remain favorable for them in the long run. A deeper understanding of the ecological implications on the species and the prey community is advisable.

Protected area networks are insufficient for the conservation of threatened farmland species: A case study on corncrake (Crex crex) and lesser grey shrike (Lanius minor) in Serbia

To conserve threatened farmland species requires an estimate of the representation of their habitats within protected areas, especially in countries with inadequate mechanisms for protecting and managing habitats outside of protected areas. We conducted a gap analysis to evaluate the conservation status of suitable habitats for two threatened farmland bird species - corncrake (Crex crex) and lesser grey shrike (Lanius minor) - within the networks of national protected areas (NPAs) and important bird areas (IBAs) in Serbia. We determined the distribution of suitable habitats using MaxEnt based on climate, topography and land-cover variables. We found that the proportion of suitable habitats within the NPAs is very low (12.31% and 2.04% for the corncrake and lesser grey shrike, respectively), although it is significantly higher for both species within IBAs (25.86% and 9.91%, respectively). Upland farmland habitats (preferred by corncrake) are better represented within both networks (especially IBAs) than lowland habitats (preferred by lesser grey shrike). Our spatially explicit distribution models identify suitable habitats within and beyond the NPAs and IBAs that require monitoring and appropriate conservation measures. The low representation of suitable habitats within these networks is an obstacle to the conservation of both species and other farmland birds in Serbia.

Land-use change has no detectable effect on reproduction of a disturbance-adapted, hawkmoth-pollinated plant species.

Land-use change is cited as a primary driver of global biodiversity loss, with myriad consequences for species, populations, and ecosystems. However, few studies have examined its impact on species interactions, particularly pollination. Furthermore, when the effects of land-use change on pollination have been studied, the focus has largely been on species pollinated by diurnal pollinators, namely, bees and butterflies. Here, we focus on Oenothera harringtonii, a night-flowering, disturbance-adapted species that has experienced a range-wide gradient of land-use change. We tested the hypothesis that the negative impacts of land-use change are mitigated by long-distance pollination. Our study included both temporal (4 yr) and spatial (19 populations range-wide, and 1, 2, and 5 km from the population center) data, providing a comprehensive understanding of the role of land-use change on pollination biology and reproduction. We first confirmed that O. harringtonii is self-incompatible and reliant on pollinators for reproduction. We then showed that hawkmoths (primarily Hyles lineata) are highly reliable and effective pollinators in both space and time. Unlike other studies, we did not detect an effect of population size, increased isolation, or a reduction in suitable habitat in areas with evidence of land-use change on pollination (visitation, pollen removal and deposition). Furthermore, the proportion of suitable habitat and other fragmentation metrics examined were not associated with population size or density in this plant species. We conclude that nocturnal pollination of Oenothera harringtonii via hawkmoths is robust to the negative impacts of land-use change.

The European Distribution of <i>Sus Scrofa</i>. Model Outputs from the Project Described within the Poster – Where are All the Boars? An Attempt to Gain a Continental Perspective

Wild boar is a host of a number of arthropod-vectored diseases and its numbers are on the rise in mainland Europe. The species potentially impacts ecosystems, humans and farming practices and so its distribution is of interest to policy makers in a number of fields beyond that of the primarily epidemiological goal of this study.Three statistical model outputs describing the distribution and abundance of the species Sus scrofa (Wild boar) are included in this data package. The extent of this dataset covers continental Europe. These data were presented as a poster [1] at the conference Genes, Ecosystems and Risk of Infection (GERI 2015).The first of the three models provide a European map presenting the probability of presence of Sus scrofa, which can be used to describe the likely geographical distribution of the species. The second and third models provide indices to help describe the likely abundance across the continent. The two indices include “the proportion of suitable habitat where presence is estimated” and a simple classification of boar abundance across Europe using quantiles of existing abundance data and proxies.

Habitat availability for amphibians and extinction threat: a global analysis

AbstractAimHabitat loss and degradation are the factors threatening the largest number of amphibian species. However, quantitative measures of habitat availability only exist for a small subset of them. We evaluated the relationships between habitat availability, extinction risk and drivers of threat for the world's amphibians. We developed deductive habitat suitability models to estimate the extent of suitable habitat and the proportion of suitable habitat (PSH) inside the geographic range of each species, covering species and areas for which little or no high‐resolution distribution data are available.LocationGlobal.MethodsWe used information on habitat preferences to develop habitat suitability models at 300‐m resolution, by integrating range maps with land cover and elevation. Model performance was assessed by comparing model output with point localities where species were recorded. We then used habitat availability as a surrogate of area of occupancy. Using the IUCN criteria, we identified species having narrow area of occupancy, for which extinction risk is likely underestimated.ResultsWe developed models for 5363 amphibians. Validation success of models was high (94%), being better for forest specialists and generalists than for open habitat specialists. Generalists had proportionally more habitat than forest or open habitat specialists. The PSH was lower for species having small geographical ranges, currently listed as threatened, and for which habitat loss is recognized as a threat. Differences in habitat availability among biogeographical realms were strong. We identified 61 forest species for which the extinction risk may be higher that currently assessed in the Red List, due to limited extent of suitable habitat.Main conclusionsHabitat models can accurately predict amphibian distribution at fine scale and allow describing biogeographical patterns of habitat availability. The strong relationship between amount of suitable habitat and extinction threat may help the conservation assessment in species for which limited information is currently available.

Factors explaining the occurrence of the Siberian flying squirrel in urban forest landscape

Urban forests are often modified and fragmented by human land use and the original habitat might exist only in remnant patches. Due to their specific habitat requirements and unwillingness to move through matrix many forest-dwelling mammals are susceptible to changes in landscape structure. It is important to understand how the availability of suitable habitat and landscape fragmentation affect species distributions, and what landscape characteristics are essential to the persistence of a given species to conserve urban wildlife. We investigated the effect of landscape composition and configuration on the occurrence of the Siberian flying squirrel, a small-sized arboreal rodent, in a partly urbanized area of Eastern Finland. All suitable and potential forest patches were searched to determine the presence or absence of species, and the landscape characteristics of occupied sites were compared to those of unoccupied sites. Flying squirrels occurred both at the edges of large suitable forested areas, but also in small forest fragments within residential areas. Surprisingly, urban areas did not have a negative effect on the flying squirrel occurrence. Occurrence probability was not either associated with the proportion of suitable habitat, but occupied sites contained larger amount of movement habitat and had shorter distances to nearest occupied sites than unoccupied sites. Our results show that flying squirrels can exist in urbanized landscape and near residential areas, but more detailed information on habitat use and survival is still needed to determine the long-term persistence and viability of the urban populations.

Waldbauliche Massnahmen für das Auerhuhn im Sonderwaldreservat Amden: ein erstes Fazit

Silvicultural habitat restoration measures for the capercaillie in the special forest reserve of Amden: a first review As a threatened forest grouse species, the capercaillie (Tetrao urogallus) depends on conservation actions in core areas of its Alpine distribution. In this study, we looked at the species' response to silvicultural measures in the special forest reserve of Amden in the canton of St. Gallen, Switzerland. Here, silvicultural measures were taken between 2006 and 2009 in stands that had previously been classified as less or not suitable for capercaillie. In summer 2010, we investigated how stands used by the species differed from unused ones by relating indirect evidence of species presence with forest structural and compositional variables. Evidence of species' habitat use was found in 12 out of 33 surveyed stands. Used stands showed a significantly higher share of bilberry in the ground vegetation layer, a higher proportion of coniferous trees and a lower canopy cover. Furthermore, the proportion of suitable habitat in immediate vicinity of the treated forest stand was higher in used stands. Our results support that habitat restoration by logging is a promising method to improve capercaillie habitat, in particular in fir-spruce forests, where the effectivity of restoration measures was higher compared to fir-beech forests. Hence, managing guidance for the future selection of stands for restoration should be based on habitat suitability of the stand itself and on an appropriate habitat quality of adjacent forest stands.

Comparing multiple species distribution proxies and different quantifications of the human footprint map, implications for conservation

Anthropogenic threats drive species to extinction and are the focus of extinction risk analyses and conservation planning. Threats are often quantified through higher level proxies, such as the human footprint (HF). We tested the effects that multiple methods of representing species’ distribution and different quantifications of a HF map have on threat measurement, and how these influence conservation decisions. We quantified the magnitude of HF for 901 Southeast Asian mammals according to several methods. We ranked the species according to the measured HF value, and produced priority lists of top-impacted species. The different representations of species’ distribution caused significant disagreement in HF calculations. HF values were on average lower when calculated in species’ suitable habitat or occurrence points in comparison to the whole geographic range. Biases were non-linear and dependent on distal factors, such as the proportion of suitable habitat within species’ range and species’ habitat specialism. Using different HF quantifications also yielded disagreement, with 2–56% difference observed in species membership among priority lists. Threatened species were best predicted, and significantly placed in the top-ranking, when measuring their proportion of range exposed to high levels of HF. We thus show that the HF extent, not only its average value, determines species extinction risk. A well-framed global conservation strategy must address the quantification of human impact on biodiversity. The selection of quantification methods has implications for how such impact is evaluated. Improving techniques to quantify biodiversity threats will enhance the effectiveness of extinction risk analyses and conservation decisions.

The Spatial Distribution of Chacma Baboon (Papio ursinus) Habitat Based on an Environmental Envelope Model

Predictive spatial modeling has become a key research tool for species distribution modeling where actual data are limited. Although qualitative maps and distribution descriptions for chacma baboons (Papio ursinus) are freely available, quantitative data are limited and do not provide the empirical information required to make informed decisions about issues such as population assessment, conservation, and management. Here we present the first quantitative, repeatable, and detailed predicted spatial distribution of the chacma baboon across southern Africa. Our distribution is at a finer level of detail than has previously been available. We used an environmental envelope model implemented within a geographic information system to achieve this. The model used environmental layers representing water availability, temperature and altitude, and model parameters determined from georeferenced observational data. The data extracted from the environmental layers suggest chacma baboons inhabit areas with mean minimum temperatures of the coolest month as low as −6.1 °C, mean maximum temperatures of the warmest month as high as 38.2 °C, mean annual rainfall up to 1,555 mm, and altitude up to 3,286 m. Our model demonstrates that the distribution of chacma baboons may be limited by temperature and rainfall, with the predicted northern extent of its range being temperature dependent. The model also implies that some areas well known for chacma baboon occupation today may in fact be marginal habitat. The resulting map highlights areas of suitable habitat in southern Africa. In addition, a linear “patchy” corridor was identified following the East African Rift Valley connecting the southern habitat with northeast Africa. We find the greatest proportion of suitable habitat to be located in South Africa. This modeling approach is generic and would be suitable to analyze other primate species across similar geographic extents.

The Speed of Range Shifts in Fragmented Landscapes

Species may be driven extinct by climate change, unless their populations are able to shift fast enough to track regions of suitable climate. Shifting will be faster as the proportion of suitable habitat in the landscape increases. However, it is not known how the spatial arrangement of habitat will affect the speed of range advance, especially when habitat is scarce, as is the case for many specialist species. We develop methods for calculating the speed of advance that are appropriate for highly fragmented, stochastic systems. We reveal that spatial aggregation of habitat tends to reduce the speed of advance throughout a wide range of species parameters: different dispersal distances and dispersal kernel shapes, and high and low extinction probabilities. In contrast, aggregation increases the steady-state proportion of habitat that is occupied (without climate change). Nonetheless, we find that it is possible to achieve both rapid advance and relatively high patch occupancy when the habitat has a “channeled” pattern, resembling corridors or chains of stepping stones. We adapt techniques from electrical circuit theory to predict the rate of advance efficiently for complex, realistic landscape patterns, whereas the rate cannot be predicted by any simple statistic of aggregation or fragmentation. Conservationists are already advocating corridors and stepping stones as important conservation tools under climate change, but they are vaguely defined and have so far lacked a convincing basis in fundamental population biology. Our work shows how to discriminate properties of a landscape's spatial pattern that affect the speed of colonization (including, but not limited to, patterns like corridors and chains of stepping stones), and properties that affect a species' probability of persistence once established. We can therefore point the way to better land use planning approaches, which will provide functional habitat linkages and also maintain local population viability.

Short seed‐dispersal distances and low seedling recruitment in farmland populations of bird‐dispersed cherry trees

Summary In Central Europe, many plant populations are patchily distributed in human‐modified landscapes and depend on animal vectors for seed dispersal. To predict seed‐dispersal distances and locations of seeds of wild cherry trees (Prunus avium L.) in forest and farmland habitats in a human‐modified landscape, we integrate movement data and seed regurgitation times of the Common Blackbird (Turdus merula L.) in a simulation model. We performed feeding trials with Common Blackbirds and wild cherries to determine the distribution of regurgitation times. We captured 32 male blackbirds and equipped them with radio tags to follow their movements in forest and farmland habitats. To simulate the movement of cherry seeds through the landscape, we combined the distribution of regurgitation times with bird movement data and modelled seed‐dispersal distances and locations of seed deposition for forest and farmland birds. According to our simulations, more cherry seeds were deposited under foraging trees in farmland (20.8%) than in forest populations (9.5%). Median seed‐dispersal distances (50.8 vs. 68.2 m) and the proportion of long‐distance dispersal events (distances > 100 m) were predicted to be lower in farmland (14.9%) than in forest populations (28.2%). In the model, forest‐dwelling blackbirds dispersed more cherry seeds into suitable habitat (98.7%) than farmland blackbirds (85.4%). In both habitats, seed deposition in suitable habitat was much higher than expected from the proportion of suitable habitat within blackbirds' home ranges, indicating directed dispersal. To test whether differences in seed‐dispersal locations were related to recruitment success, we recorded seedling densities in farmland and forest populations of P. avium and determined survival probabilities of seedlings. Seedling densities and survival were much lower in farmland than in forest populations, even accounting for strong environmental effects on seedling recruitment. Synthesis: Our findings show that behavioural differences of animal seed dispersers between habitat types can result in substantial changes in seed‐dispersal distances and locations in human‐modified habitats. These changes in seed‐dispersal services for bird‐dispersed plant species may be related to reduced seedling recruitment in farmland populations making such populations prone to extinction in the long term.

Evaluating the relationship between trapper harvest of American martens (Martes americana) and the quantity and spatial configuration of habitat in the boreal forests of Ontario, Canada

We investigated the relationship between trapper harvest of martens (Martes americana) and the quantity and spatial configuration of marten habitat on traplines in the eastern and western boreal forests of Ontario. We used region-specific habitat models to estimate the total amount of suitable marten habitat on each trapline, and the proportion of each trapline identified as suitable habitat in various patch size classes. To control for variability in trapper success not associated with habitat, we included an index of trapper effort, as well as variables related to access, temperature, and precipitation as covariates in our regression analyses. Region-specific habitat models identified a positive relationship between the proportion of suitable marten habitat on traplines (irrespective of patch size) and trapper success. Although there did not appear to be an effect of patch size on trapper success in the eastern study region, we observed an effect in the western region. Results from the western study region suggest that traplines with suitable habitat in patches ≥500 ha will have higher trapper success than traplines with similar proportions of suitable habitat but distributed in smaller patches. Our study was conducted in a forested landscape (80% of trapline area was forested). Therefore, our findings should not be applied to areas where suitable marten habitat lies in a matrix comprised of a significant amount of non-forested area.

Plant communities of cultivated fields of the Podlaski Przełom Bugu mesoregion part vi. communities of root crops on compact soils

Analysis of plant communities accompanying root crops on compact soils is presented in the paper. It is the next part of the review of plant communities of agrocenoses of the Podlaski Przełom Bugu (Podlasie Bug Gorge) mesoregion. The studied phytocoenoses were identified on the basis of 103 phytosociological relevés, made according to the Braun-Blanquet method. In the studied agrocenoses, plots of the associations <i>Lamio-Veronicetum politae</i>, <i>Galinsogo-Setarietum</i> and <i>Oxalido-Chenopodietum polyspermi</i> from the <i>Polygono-Chenopodion polyspermi</i> alliance were noted. Small patches of <i>Lamio-Veronicetum</i> and <i>Oxalido-Chenopodietum</i> were rarely noted in the studied area due to a small proportion of suitable habitats. In the area of Podlaski Przełom Bugu mesoregion, phytocoenoses of <i>Oxalido-Chenopodietum</i> developed in the river valleys on fertile muds and black soils. Typical plots of <i>Galinsogo-Setarietum</i> distinguishable by the mass occurrence of <i>Galinsoga parviflora</i> were only observed in the vicinity of farm buildings. Intermediate communities between <i>Panico-Setarion</i> and <i>Polygono-Chenopodion</i> polyspermi as well as phytocoenoces of <i>Echinochloo-Setarietum typicum</i> - subvariant with <i>Veronica persica</i> and <i>Echinochloo-Setarietum fumarietosum</i> - were also quite frequently noted in root crops on compact soils.

Global habitat suitability models of terrestrial mammals.

Detailed large-scale information on mammal distribution has often been lacking, hindering conservation efforts. We used the information from the 2009 IUCN Red List of Threatened Species as a baseline for developing habitat suitability models for 5027 out of 5330 known terrestrial mammal species, based on their habitat relationships. We focused on the following environmental variables: land cover, elevation and hydrological features. Models were developed at 300 m resolution and limited to within species' known geographical ranges. A subset of the models was validated using points of known species occurrence. We conducted a global, fine-scale analysis of patterns of species richness. The richness of mammal species estimated by the overlap of their suitable habitat is on average one-third less than that estimated by the overlap of their geographical ranges. The highest absolute difference is found in tropical and subtropical regions in South America, Africa and Southeast Asia that are not covered by dense forest. The proportion of suitable habitat within mammal geographical ranges correlates with the IUCN Red List category to which they have been assigned, decreasing monotonically from Least Concern to Endangered. These results demonstrate the importance of fine-resolution distribution data for the development of global conservation strategies for mammals.