Breaking out from a restricted range: Alternative habitat models to assess population perspectives

Habitat conservation for restricted-range species should also consider adjacent areas, but the analytical approaches for such assessments (particularly for a future perspective) are constrained by currently observed habitat relationships. We used two conceptually different habitat modelling approaches for analysing habitat distribution for the isolated Estonian population of a species of European conservation concern, the Siberian flying squirrel (Pteromys volans (Linnaeus, 1758)). We expected that the correlative (statistical) approaches based on current location data will increasingly deviate along with the distance from the current range, compared with a mechanistic approach based on limiting factors for the species. For conservation planning, we also investigated how the current protected area network covers quality habitats around the current range. We constructed three alternative correlative models (MaxEnt; Random forest; Generalized Boosted Regression) utilizing remote-sensing (Sentinel-2; LiDAR) and forest inventory data for 1299 occurrences in the currently occupied ca. 1400 km² range. A mechanistic model was constructed as a decision tree that distinguished 11 quality classes of forest land based on the ecological prioritization of limiting factors: site type; forest cover; abundance of key tree species; stand age; patch size; and layer structure. Supporting our expectation, an overall good accordance of habitat predictions of all the correlative models and the mechanistic model (at 30 × 30 m pixel size) declined with the distance from the current range. The MaxEnt model most closely followed the full range of habitat quality classes of the mechanistic model, while the other correlative models emphasized the highest habitat-quality class. Within the current range, both MaxEnt and the mechanistic model similarly revealed habitat quality differences between occupied and unoccupied species protection areas. Delineation of habitat aggregations all over the country based on the mechanistic model revealed habitat loss both within and adjacent to the current range, which sets limits to local population recovery. For analysing wider options, we recommend complementing statistical spatial modelling of current conditions with ecologically sound mechanistic approaches. Based on our specific case, we outline how such model predictions can be assessed for management planning beyond current range.     

An indicator system to assess ecological integrity of managed forests

Ecological integrity of managed forests includes the ability of an ecosystem to support a community of organisms with a similar species composition and functional organization as found in nearby natural systems. We developed an indicator system for ecological integrity based on simulated natural disturbance and indicator species to test if forest condition and habitat in managed forests are similar to that found or expected in natural systems. We then applied the method in an area of the boreal forest (Ontario, Canada) where the objective of Ontario's strategic forest management planning approach is, in part, to conserve ecological integrity through the emulation of the natural disturbance process. Forest condition controls the supply of habitat to support the diversity of native organisms, and historically in boreal forests the natural disturbance process drove forest condition. We selected indicators of forest condition (landscape pattern and compositional mosaic) and habitat function (occupancy rates for a broad range of forest birds), and applied our assessment system to test whether indicators of forest condition and habitat function reflect outcomes expected if natural disturbance processes were successfully emulated. We collected occupancy data in natural and managed forest disturbance types using autonomous acoustic recorders, applied occupancy/detection modeling to estimate corrected occupancy rates (ψ), and then tested for differences in ψ between disturbance types. Some indicators of forest condition were within the range expected under natural disturbance, but we found relatively less old conifer, more young deciduous and greater edge density in managed forests relative to forests of natural disturbance origin. Most species (11 of 14) occurred with equal ψ in habitat originating from the two disturbance types. Brown creeper (Certhia americana), bay-breasted warbler (Mniotilta varia) and red-eyed vireo (Vireo olivaceus) differed between disturbance types. Brown creeper uses older conifer and occurred at lower rates in managed forest, while red-eyed vireo uses a range of deciduous forest ages, and occurred at higher rates in managed forest. Differences in quantity and/or quality of specific habitat types likely explain the responses. The results suggest what directional changes in the forest pattern and compositional mosaic would improve ecological similarity with natural systems, but also indicate what further research is required. We believe this approach to assessing ecological integrity can be adapted to study the effectiveness of conservation management strategies in other systems, and will contribute to adaptive management approaches and evidence-based policy development.     

Habitat selection of European pine marten in Central Italy: from a tree dependent to a generalist species

Studies at small spatial scale are often fundamental to highlight the behavioural plasticity of a species and thus have important implications for conservation planning, in particular for species usually considered as habitat specialists. We investigated second-order habitat selection of the European pine marten in an area dominated by deciduous oak forest and open fields in central Italy, by radio-tracking 16 pine martens (eight males, eight females). Pine martens placed home ranges in areas with more open field than in the study area, whereas woodland (oak and conifer forests) comprised a smaller portion of the home range than predominant forest character of the studied area. Although the presence of the species in the open habitats has been documented, to our knowledge, our results provide the first evidence of home range establishment in this cover type by pine marten at population level. The combination of low predation risk and high availability of resources could allow pine martens to occupy open fields in our study area. We highlighted different individual strategies of habitat selection, with some individuals placing home ranges in areas with high forest coverage while others occupying open areas. We found no effects of sex and body condition on habitat selection, and this could indicate that in the study area, both forested and non-forested cover types, such as open fields, shrub and anthropic areas, can provide adequate food, overhead cover and resting sites for all individuals. Pine marten ability to occupy open fields seems thus more related to the behavioural flexibility of the species, rather than to the need to supplement dens and forage from complementary lower quality habitat. The high quality of the Mediterranean continental area studied could also explain the selection of open areas by the pine marten. Our results offer useful information on pine marten ecology and may be helpful for conservation management of this species in southern Europe.     

Combining population monitoring with habitat vulnerability to assess conservation status in populations of rare and endangered plants

In this paper, we propose an integrative framework to assess the conservation status of rare plant populations that combines population trends with four criteria to assess habitat vulnerability. We illustrate how population trends can be studied using a presence/absence method for a species that is inappropriate for a demographic study. The four other criteria concern habitat fragmentation, the human footprint in the surrounding landscape, observed impacts on a population and elements of habitat structure and quality that may impinge on population status. Each criterion is assessed with various indicators that can be adapted to the biology and ecology of the studied species. To test the feasibility of the proposed framework, we perform a case study of a Mediterranean geophyte Allium chamaemoly L., a species listed for protection in France. The results show a wide range of conservation status among a regional set of populations in the study species. Variation among the indicators used to assess different criteria illustrates the importance of assessing a range of different factors and ways to combine them if population conservation status is to be objectively identified. The study of diverse criteria may allow for a more precise assessment of the causes of differences in conservation status among populations of a single species. The framework of five criteria could be adapted by modification or substitution of indicators or adaptation of thresholds among classes, and thus be applied to other species of conservation importance.     

Fishing cat Prionailurus viverrinus distribution and habitat suitability in Nepal

The fishing cat Prionailurus viverrinus is a wetland specialist species endemic to South and Southeast Asia. Nepal represents the northern limit of its biogeographic range, but comprehensive information on fishing cat distribution in Nepal is lacking. To assess their distribution, we compiled fishing cat occurrence records (n = 154) from Nepal, available in published literature and unpublished data (2009–2020). Bioclimatic and environmental variables associated with their occurrence were used to predict the fishing cat habitat suitability using MaxEnt modeling. Fishing cat habitat suitability was associated with elevation (152–302 m), precipitation of the warmest quarter, i.e., April–June (668–1014 mm), precipitation of the driest month (4–7 mm), and land cover (forest/grassland and wetland). The model predicted an area of 4.4% (6679 km²) of Nepal as potential habitat for the fishing cat. About two‐thirds of the predicted potentially suitable habitat lies outside protected areas; however, a large part of the highly suitable habitat (67%) falls within protected areas. The predicted habitat suitability map serves as a reference for future investigation into fishing cat distribution as well as formulating and implementing effective conservation programs in Nepal. Fishing cat conservation initiatives should include habitats inside and outside the protected areas to ensure long‐term survival. We recommend conservation of wetland sites, surveys of fishing cats in the identified potential habitats, and studying their genetic connectivity and population status.     

Environmental diagnosis: Integrating biodiversity conservation in management of Natura 2000 forest spaces

The conservation of biodiversity in Europe is defined by Directive 92/43/EEC – commonly known as the Habitats Directive – relating to the conservation of natural habitats and of wild flora and fauna. This Directive established the creation of an ecological network of European protected areas – the Natura 2000 network – , and also recognised the need to manage these areas to maintain their “favourable conservation status”.This paper proposes a methodology which enables the conservation of biodiversity to be integrated into the management of Natura 2000 forest spaces. The methodology comprises an “environmental diagnosis” in three phases. The first phase evaluates the current conservation status of habitats using the following criteria: vital functions; floristic richness; forest structure; area occupied by the habitat; and recovery capacity. The second phase assesses the fragility of the space to determine the degree of vulnerability of habitats. This involves evaluating the fire hazard, erosion hazard, and the fragility of the vegetation. The last phase combines the two previous ones to generate management areas (optimum, intermediate or unfavourable) and to prioritise management actions.This methodology was applied in a protected forest area in the Natura 2000 network, located in Avila (Spain). Different management areas were generated for biodiversity conservation, and each habitat was associated to one of them. Finally, actions were prioritised and designed to raise the habitats to a “favourable conservation status”.     

Quantitatively defining the conservation status of Natura 2000 forest habitats and improving management options for enhancing biodiversity

The main goal of Natura 2000 network is to guarantee the favourable conservation status of habitats and species ensuring European biodiversity. As a result, certain forest areas have been included in this network listed as 9230-Quercus pyrenaica habitat and 9340-Quercus ilex subsp. rotundifolia forest habitat. These areas were previously used for firewood extraction or livestock grazing and browsing. Nowadays these habitats are coppice forests with asexual regeneration, which is far from the desired conservation status. Traditional timber harvesting plans do not take account of the new objectives required for these Natura sites, which attempt to ensure biodiversity and recreational uses instead of simply focusing on timber production. This paper proposes a flexible methodology (applied to the study area “Dehesa Boyal” in ávila, Spain) for managing Natura 2000 forest sites by stands for sustainable forest management and the new requirements. The methodology has two phases. The first, “Division of the forest area into stands”, defines homogeneous patches of vegetation distinct in species composition, physiognomic structure and future management. The second, “Conservation status assessment of stands”, quantifies the conservation status of each previously classified stand considering a series of factors such as: functional health, restoration, floral richness and structure. A total value integrating the conservation status of stands is then calculated for the habitat. Both phases use Geographic Information System tools for managing information and visualizing results. The proposed methodology provides forest managers with a good knowledge of the territory and subsequently enables them to take appropriate conservation measures to maintain biodiversity.     

Landscape connectivity dynamics based on network analysis in the Xishuangbanna Nature Reserve,China

Lack of landscape connectivity and habitat loss is major threats to biodiversity and ecosystem integrity in nature reserves aimed at conservation. In this study, we used structural pattern and functional connectivity metrics to analyze the spatial patterns and landscape connectivity of habitat patches for the Shangyong sub-reserve of the Xishuangbanna Nature Reserve from 1970, 1990, and 2000. On the basis of vegetation and land cover data, we applied the equivalent connected area ECA(PC) indicator to analyze the changes in forest connectivity. Four distance thresholds (2, 4, 8, 12 km) were considered to compare the patch importance of connectivity by dECA values. The results showed the declining trends of landscape connectivity measured by ECA(PC) index from 1970 to 2000. The importance of connectivity in each forest patch varied with the increment of dispersal distances at the patch level, and some important habitat patches, which exhibit a potential to enhance landscape connectivity, should be given more attention. The least-cost pathways based on network structure were displayed under four dispersal distances in three periods. The results showed that the number of paths among the fragments of forest patches exhibited radical increases for larger dispersal distances. Further correlation analyses of AWF, ECA (IIC), and ECA (PC) showed the weakest and least-frequent correlations with the structural pattern indices, while H presented more significant correlations with the PD fragmentation metric. Furthermore, Kendall's rank correlations between the forest patch area and functional connectivity indicators showed that dECA (PC) and dAWF indicators should provided the area-based prioritization of habitat patches. Moreover, the low-rank correlations showed that dF and dLCP can be considered as effective and appropriate indicators for the evaluation of habitat features and network patterns.     

Linking species distribution and territorial planning to the management of the endangered Gonopterodendron sarmientoi in native forests of the Chaco region,Argentina

For management and conservation strategies in the long term is necessary to know the species distribution and main biophysical aspects that determine the structure and dynamics of the forest. The aim of this work was to determine the potential and current spatial distribution of Gonopterodendron sarmientoi, an emblematic and endangered tree species of the Dry Chaco. A further aim was to superimpose the distribution of G. sarmientoi, with the zonation in the current Territorial Planning of Native Forests (OTBN, its acronym in Spanish) to provide basic information for conservation and management of the species. For this, a Maxent model was developed to quantify the relationship between G. sarmientoi occurrence and key environmental variables (including water, topography, and climate as a variables). G. sarmientoi’s habitat was mainly influenced by precipitation variables, and secondarily by temperature variables. Considering the OTBN defined by the local forest authority, of the current area of G. sarmientoi (2,477,009 ha), the majority (57.9%) corresponded to the yellow category (forest areas with medium conservation value) and only 10.6% to the red category (high conservation value). It is important to note that around 600,686 ha (24.3%) of native forest with G. sarmientoi is in the green category (low conservation value) subject to change in land use, and 178,107 ha was uncategorized forest (7.2%). For effective management and conservation strategies, the current habitat distribution map of G. sarmientoi provides decision-makers an opportunity to review and adjust the native forests zoning at a provincial scale within the framework of the OTBN, mainly the green category (legal deforestation) with the occurrence of the endangered G. sarmientoi.     

Factors affecting seasonal habitat use,and predicted range of two tropical deer in Indonesian rainforest

There is an urgent recognized need for conservation of tropical forest deer. In order to identify some environmental factors affecting conservation, we analyzed the seasonal habitat use of two Indonesian deer species, Axis kuhlii in Bawean Island and Muntiacus muntjak in south-western Java Island, in response to several physical, climatic, biological, and anthropogenic variables. Camera trapping was performed in different habitat types during both wet and dry season to record these elusive species. The highest number of photographs was recorded in secondary forest and during the dry season for both Bawean deer and red muntjac. In models, anthropogenic and climatic variables were the main predictors of habitat use. Distances to cultivated area and to settlement were the most important for A. kuhlii in the dry season. Distances to cultivated area and annual rainfall were significant for M. muntjak in both seasons. Then we modelled their predictive range using Maximum entropy modelling (Maxent). We concluded that forest landscape is the fundamental scale for deer management, and that secondary forests are potentially important landscape elements for deer conservation. Important areas for conservation were identified accounting of habitat transformation in both study areas.     

Suitability index for restoration in landscapes: An alternative proposal for restoration projects

Forest fragmentation constitutes one of the main consequences of land cover change worldwide. Through this process gaps in habitat coverage are created and the ability of populations in the remaining fragments to maintain themselves is put in doubt. Hence, two options need to be considered: conserving the remaining forest fragments, and restoring habitat in some deforested patches with the aim of reestablishing the connections among the fragments. We established a mathematical index (SIR) that describes the suitability of individual habitat patches for restoration within a landscape. The index considers classes of distances among fragments and categories of habitat quality in the areas surrounding the fragments to assess habitat quality in terms of probability of dispersal and survival of propagules (especially seeds and cutting). In the present study, we created detailed maps depicting SIR values for two periods (1988 and 2011) for Sorocaba region (São Paulo State, Brazil). We derived land cover maps from satellite images for the two years of our study, and then surveyed the transition of land cover categories and landscape metrics between years. A model for the SIR was created using a map of distance classes among fragments and also a map of habitat quality established according to each land cover category. For both 1988 and 2011, pasture was the predominant land cover category. The main land cover transitions were from pasture to urban (10.6%) and from pasture to forest fragments (13.4%). Although the land cover class “wood sites” increased, the data of SIR revealed that the areas of habitat categorized as excellent and good both decreased, while habitat classes categorized as poor and very poor increased. Our model has the potential to be applied to other regions where the forest is fragmented. Hence, local policy makers will be able to use this model to determine local patches of high value for conservation and also the most ideal locations for restoration projects.     

A forest typology for monitoring sustainable forest management: The case of European Forest Types

Abstract

Sustainable forest management (SFM) is presently widely accepted as the overriding objective for forest policy and practice. Regional processes are in progress all over the world to develop and implement criteria and indicators of SFM. In continental Europe, a set of 35 Pan-European indicators has been endorsed under the Ministerial Conference on the Protection of Forests in Europe (MCPFE) to measure progress towards SFM in the 44 countries of the region. The formulation of seven indicators (forest area, growing stock, age structure/diameter distribution, deadwood, tree species composition, damaging agents, naturalness) requires national data to be reported by forest types. Within the vast European forest area the values taken by these indicators show a considerable range of variation, due to variable natural conditions and anthropogenic influences. Given this variability, it is very difficult to grasp the meaning of these indicators when taken out of their ecological background. The paper discusses the concepts behind, and the requirements of, a classification more soundly ecologically framed and suitable for MCPFE reporting than the three (un-informative) classes adopted so far: broadleaved forest, coniferous forest, mixed broadleaved and coniferous forest. We propose a European Forest Types scheme structured into a reasonably higher number of classes, that would improve the specificity of the indicators reported under the MCPFE process and its understanding.     

Where are Europe’s last primary forests?

Aim

Primary forests have high conservation value but are rare in Europe due to historic land use. Yet many primary forest patches remain unmapped, and it is unclear to what extent they are effectively protected. Our aim was to (1) compile the most comprehensive European‐scale map of currently known primary forests, (2) analyse the spatial determinants characterizing their location and (3) locate areas where so far unmapped primary forests likely occur.

Location

Europe.

Methods

We aggregated data from a literature review, online questionnaires and 32 datasets of primary forests. We used boosted regression trees to explore which biophysical, socio‐economic and forest‐related variables explain the current distribution of primary forests. Finally, we predicted and mapped the relative likelihood of primary forest occurrence at a 1‐km resolution across Europe.

Results

Data on primary forests were frequently incomplete or inconsistent among countries. Known primary forests covered 1.4 Mha in 32 countries (0.7% of Europe’s forest area). Most of these forests were protected (89%), but only 46% of them strictly. Primary forests mostly occurred in mountain and boreal areas and were unevenly distributed across countries, biogeographical regions and forest types. Unmapped primary forests likely occur in the least accessible and populated areas, where forests cover a greater share of land, but wood demand historically has been low.

Main conclusions

Despite their outstanding conservation value, primary forests are rare and their current distribution is the result of centuries of land use and forest management. The conservation outlook for primary forests is uncertain as many are not strictly protected and most are small and fragmented, making them prone to extinction debt and human disturbance. Predicting where unmapped primary forests likely occur could guide conservation efforts, especially in Eastern Europe where large areas of primary forest still exist but are being lost at an alarming pace.     

Distribution of ground-dwelling beetles in fragmented tropical habitats

The conservation of biodiversity is increasingly dependent on human-altered habitats. In a fragmented forest landscape in northern Costa Rica within the Mesoamerican Biological Corridor, an area of great conservation importance, we compared the diversity and composition of ground-dwelling beetle communities in five habitat types along a gradient of increasing disturbance: primary forest, logged forest, secondary forest, plantation (Gmelina arborea) and pasture. Using pitfall trapping we captured a total of 1,877 beetles (Coleoptera), comprising 422 morphospecies in 26 families. The plantation sites had the lowest number of species followed by secondary forest and pasture. Multivariate analysis separated the beetle fauna according to land use, and suggested that only the logged forest maintains a similar species assemblage to primary forest. However, each habitat harboured a number of unique species indicating the conservation value of the mosaic of habitats found in fragmented landscapes. Our results suggest that to maintain forest beetle species diversity it is essential that areas of natural forest are conserved. However, other land uses also provide beetle habitats and in fragmented areas active management to maintain a mosaic of land uses will contribute to the conservation of beetle diversity.     

Government targets for protected area management: will threatened butterflies benefit?

The UK Government has set targets for biodiversity conservation in England based on several indicators, including the status of protected areas [e.g. Sites of Special Scientific Interest (SSSIs)]. Specifically, the Government aims to achieve favourable condition [defined by Common Standards Monitoring (CSM)] on 95% by area of SSSIs by 2010. SSSIs are important for threatened butterflies and management to achieve favourable condition will play a key role in determining future population levels of these high-profile insects. Because only notified features of SSSIs are considered within CSM, we investigated the level of notification for three threatened butterflies. We found that these species were notified at only 15–33% of SSSIs where they occurred; though most site managers did manage for them under broader site conservation objectives. We investigated the relationship between SSSI condition status and population trend for eight butterfly species of conservation concern to assess the benefit to butterflies of sites attaining favourable condition status. The majority (80%) of population trends on SSSIs in favourable condition were positive, suggesting an overall beneficial impact of SSSI management. However, four of the eight species maintained lower populations at favourable condition SSSIs than at sites in one of the unfavourable condition categories. We suggest that current condition assessment based chiefly on notified vegetation communities lacks the sensitivity to identify the complex habitat conditions for these (mosaic) species. As butterflies are good indictors for a wide range of invertebrates, many species requiring fine-scale habitat heterogeneity may be at risk from the Government’s target.     

Is There a Role for Human-Dominated Landscapes in the Long-Term Conservation Management of the Critically Endangered Kipunji (Rungwecebus kipunji)?

As forest loss and degradation continues, the human-dominated landscape outside protected areas should become increasingly relevant to primate conservation. Here we consider the Tanzanian endemic kipunji, Rungwecebus kipunji, whose small extent of occurrence (42 km²) and population (1117 individuals) qualify it for Critically Endangered status on the IUCN Red List. Habitat models suggest there is limited potential for expansion within the kipunji’s current protected forest habitat. In 2010, we examined the potential conservation role of land surrounding the forests using ecological surveys and structured interviews. Land outside protected forest is dominated by subsistence agriculture interspersed with tiny forest patches (almost all <0.4 km²) that cover only 2.4 % of the surveyed area located within 10 km of the forest boundary. Habitat bordering the forest forms a “hard edge” for kipunji, although some sites with single kipunji food trees, e.g., Ficus, offer some potential for use. However, tolerance of kipunji in the agricultural landscape may be limited in areas where kipunji was recorded crop raiding maize along the forest edge, and protection/retaliatory measures are employed. The Bujingijila corridor (2.1 km²) is a priority site for reforestation, particularly in the context of ongoing “Reducing Emissions from Deforestation and Forest Degradation (REDD+)” activities. We recorded the presence of kipunji food trees and little agriculture. Bujingijila could provide habitat for an additional 88 kipunji (8 % population increase), using density estimates from a 2006 census. Bujingijila has the additional benefit of reconnecting the Mt. Rungwe and Livingstone kipunji subpopulations.     

Divergent responses of flagship,keystone and resource-limited bio-indicators to forest structure

Bio-indicators are often proposed to set conservation priorities in forest habitat owing to the difficulties of determining forest intrinsic ecological value. Here, we tested the efficacy of a number of potential bird indicator groups in monitoring beech Fagus sylvatica forest status by analyzing their associations with the spatial and structural variables of forest vegetation that indicate key ecological patterns and processes. The density of cavity nesting birds, indicating the presence of limited forest resources (resource-limited indicators), was influenced by tree species diversity, vertical species mingling and diameter, parameters reflecting maturity, gap-dynamic processes, as well as resource and shelter availability. Heterogeneity in shrub species composition, another parameter depending on forest dynamics, was positively associated with the occurrence of Capercaillie, a “flagship” species for forest conservation. The presence of woodpeckers, a “keystone” group that provides shelter and foraging substrate to other organisms, was positively affected by the basal area of standing dead trees that is indirectly associated with natural nutrient availability. These findings suggest that single indicators fail to provide a complete assessment of forest status, and their use in monitoring or managing forest ecosystem need to be contextualized to specific ecological patterns. The combined use of several indicators, representing various taxa, functions and life histories, appears to be preferable, and is logistically feasible if these can be surveyed together. Several indicators would likely display a wider range of sensitivities to the modification of natural processes and permit more comprehensive tracking of forest dynamics than single flagship, keystone or resource-limited indicators.     

Frugivorous Bats Maintain Functional Habitat Connectivity in Agricultural Landscapes but Rely Strongly on Natural Forest Fragments

Anthropogenic changes in land use threaten biodiversity and ecosystem functioning by the conversion of natural habitat into agricultural mosaic landscapes, often with drastic consequences for the associated fauna. The first step in the development of efficient conservation plans is to understand movement of animals through complex habitat mosaics. Therefore, we studied ranging behavior and habitat use in Dermanura watsoni (Phyllostomidae), a frugivorous bat species that is a valuable seed disperser in degraded ecosystems. Radio-tracking of sixteen bats showed that the animals strongly rely on natural forest. Day roosts were exclusively located within mature forest fragments. Selection ratios showed that the bats foraged selectively within the available habitat and positively selected natural forest. However, larger daily ranges were associated with higher use of degraded habitats. Home range geometry and composition of focal foraging areas indicated that wider ranging bats performed directional foraging bouts from natural to degraded forest sites traversing the matrix over distances of up to three hundred meters. This behavior demonstrates the potential of frugivorous bats to functionally connect fragmented areas by providing ecosystem services between natural and degraded sites, and highlights the need for conservation of natural habitat patches within agricultural landscapes that meet the roosting requirements of bats.     

基于随机森林模型的国家重点保护陆生脊椎动物物种优先保护区的识别

准确可靠地识别国家重点保护陆生脊椎动物物种的优先保护区,是生物多样性保护的热点问题之一。采用随机森林(random forests)模型,基于12个环境变量,对中国263种国家重点保护陆生脊椎动物建模,并预测各个物种在背景点的适生概率,迭加计算得到国家重点保护陆生脊椎动物物种的生境适宜性指数。此外,基于对生境适宜性指数的空间自相关分析,识别和确定国家重点保护陆生脊椎动物物种优先保护区,并对优先保护区目前的被保护情况进行分析。结果表明,国家重点保护陆生脊椎动物物种的优先保护区的面积为103.16万km~2,约占我国国土面积的10.90%。优先保护区主要分布在我国的西部地区,包括西南地区的秦岭-大巴山山区、云南省与印度及缅甸的交界地区、武陵山山区、喜马拉雅山-横断山脉山区、阿尔泰山脉山区、天山山脉山区、昆仑山山脉山区;东北的大、小兴安岭、东北-华南沿海地区及长江中下游地区有少量分布。优先保护区中被保护的面积为50.40万km~2,占优先保护区总面积的48.86%,保护率偏低,未被充分保护。利用系统聚类分析,将未被保护的优先保护区划分成3种优先保护顺序,以期为相关部门的决策提供科学依据,更好地保护生物多样性。     

Winter distribution and conservation status of the Sierra Nevada great gray owl

Little information is available on the winter ecology of the small, geographically isolated, genetically-unique population of great gray owls (Strix nebulosa) in the central Sierra Nevada, California. This population is comprised of facultative, elevational winter migrants and access to winter habitat is an important component of their ecology. Winter observations and remotely sensed habitat variables were used to inform a predictive model of the environmental requirements and geographic distribution of this owl population. Using the modeled distribution map we assessed the distribution of 20% probability of occurrence classes relative to owl habitat associations, ownership, current development, and projected future development patterns. Our findings indicate that high probability class (81–100%) areas and the broader joint medium/medium-high/high probability class (41–100%) areas are uncommon on the landscape (0.2% and 5.0% of study area, respectively). High probability areas were characterized by Sierran Yellow Pine forest surrounding relatively small, flat areas of grassland, wet meadow, and riparian habitats, within the mid-elevation range. Approximately 32% of the high probability areas and 48% of the medium/medium-high/high probability areas occur on private lands. Of the areas on private lands, 32% of the high probability and 42% of the medium/medium-high/high probability areas occur on currently developed lands. Projected future development on private lands indicated that an additional 12% of the high and 18% of medium/medium-high/high suitability areas are slated for development by the year 2040. Future conservation planning efforts for the great gray owl in the Sierra Nevada will need to address management issues on both public and private lands. For future planning of development projects around great gray owl wintering habitat, the results from our study supplement current knowledge of breeding distributions to provide land and wildlife managers guidance on conservation priorities. © 2011 The Wildlife Society.