Motivations for Conserving Urban Biodiversity

Abstract: In a time of increasing urbanization, the fundamental value of conserving urban biodiversity remains controversial. How much of a fixed budget should be spent on conservation in urban versus nonurban landscapes? The answer should depend on the goals that drive our conservation actions, yet proponents of urban conservation often fail to specify the motivation for protecting urban biodiversity. This is an important shortcoming on several fronts, including a missed opportunity to make a stronger appeal to those who believe conservation biology should focus exclusively on more natural, wilder landscapes. We argue that urban areas do offer an important venue for conservation biology, but that we must become better at choosing and articulating our goals. We explored seven possible motivations for urban biodiversity conservation: preserving local biodiversity, creating stepping stones to nonurban habitat, understanding and facilitating responses to environmental change, conducting environmental education, providing ecosystem services, fulfilling ethical responsibilities, and improving human well‐being. To attain all these goals, challenges must be faced that are common to the urban environment, such as localized pollution, disruption of ecosystem structure, and limited availability of land. There are, however, also challenges specific only to particular goals, meaning that different goals will require different approaches and actions. This highlights the importance of specifying the motivations behind urban biodiversity conservation. If the goals are unknown, progress cannot be assessed.     

持续提高黄土高原植被水土保持功能的配套技术(Ⅱ)造林与经营配套技术

阐明了能使防护林体系水土保持功能达到持续和稳定提高的造林和经营配套技术     

Conserving and managing the subnivium

In regions where snowfall historically has been a defining seasonal characteristic of the landscape, warming winters have reduced the depth, duration, and extent of snowpack. However, most management and conservation has focused on how aboveground wildlife will be affected by altered snow conditions, even though the majority of species that persist through the winter do so under the snowpack in a thermally stable refugium: the subnivium. Shortened winters, forest management practices, and winter recreation can alter subnivium conditions by increasing snow compaction and compromising thermal stability at the soil–snow interface. To help slow the loss of the subnivium in the face of rapidly changing winter conditions, we suggest managers adopt regional conservation plans for identifying threatened snow‐covered environments; measure and predict the effects land cover and habitat management has on local subnivium conditions; and control the timing and distribution of activities that disturb and compact snow cover (e.g., silvicultural practices, snow recreation, and road and trail maintenance). As a case study, we developed a spatially explicit model of subnivium presence in a working landscape of the Chequamegon National Forest, Wisconsin. We identified landscapes where winter recreation and management practices could threaten potentially important areas for subnivium persistence. Similar modeling approaches could inform management decisions related to subnivium conservation. Current climate projections predict that snow seasons will change rapidly in many regions, and as result, we advocate for the immediate recognition, conservation, and management of the subnivium and its dependent species.     

持续提高黄土高原植被水土保持功能的配套技术(I)森林保持水土的条件

阐述了森林保持水土的条件 ,即良好的林分结构、必要的面积比例和一定的林龄 ,揭示了成林过程中水土保持功能的动态变化 ,为研究防护林体系水土保持功能持续提高技术提供了理论基础     

Conserving tigers in working landscapes

Tiger (Panthera tigris) conservation efforts in Asia are focused on protected areas embedded in human‐dominated landscapes. A system of protected areas is an effective conservation strategy for many endangered species if the network is large enough to support stable metapopulations. The long‐term conservation of tigers requires that the species be able to meet some of its life‐history needs beyond the boundaries of small protected areas and within the working landscape, including multiple‐use forests with logging and high human use. However, understanding of factors that promote or limit the occurrence of tigers in working landscapes is incomplete. We assessed the relative influence of protection status, prey occurrence, extent of grasslands, intensity of human use, and patch connectivity on tiger occurrence in the 5400 km² Central Terai Landscape of India, adjacent to Nepal. Two observer teams independently surveyed 1009 km of forest trails and water courses distributed across 60 166‐km² cells. In each cell, the teams recorded detection of tiger signs along evenly spaced trail segments. We used occupancy models that permitted multiscale analysis of spatially correlated data to estimate cell‐scale occupancy and segment‐scale habitat use by tigers as a function of management and environmental covariates. Prey availability and habitat quality, rather than protected‐area designation, influenced tiger occupancy. Tiger occupancy was low in some protected areas in India that were connected to extensive areas of tiger habitat in Nepal, which brings into question the efficacy of current protection and management strategies in both India and Nepal. At a finer spatial scale, tiger habitat use was high in trail segments associated with abundant prey and large grasslands, but it declined as human and livestock use increased. We speculate that riparian grasslands may provide tigers with critical refugia from human activity in the daytime and thereby promote tiger occurrence in some multiple‐use forests. Restrictions on human‐use in high‐quality tiger habitat in multiple‐use forests may complement existing protected areas and collectively promote the persistence of tiger populations in working landscapes.     

Defining and Evaluating the Umbrella Species Concept for Conserving and Restoring Landscape Connectivity

Conserving or restoring landscape connectivity between patches of breeding habitat is a common strategy to protect threatened species from habitat fragmentation. By managing connectivity for some species, usually charismatic vertebrates, it is often assumed that these species will serve as conservation umbrellas for other species. We tested this assumption by developing a quantitative method to measure overlap in dispersal habitat of 3 threatened species—a bird (the umbrella), a butterfly, and a frog—inhabiting the same fragmented landscape. Dispersal habitat was determined with Circuitscape, which was parameterized with movement data collected for each species. Despite differences in natural history and breeding habitat, we found substantial overlap in the spatial distributions of areas important for dispersal of this suite of taxa. However, the intuitive umbrella species (the bird) did not have the highest overlap with other species in terms of the areas that supported connectivity. Nevertheless, we contend that when there are no irreconcilable differences between the dispersal habitats of species that cohabitate on the landscape, managing for umbrella species can help conserve or restore connectivity simultaneously for multiple threatened species with different habitat requirements. Definición y Evaluación del Concepto de Especie Paraguas para Conservar y Restaurar la Conectividad de Paisajes     

Using Wildlife Communities to Improve Vegetation Classification for Conserving Biodiversity

Determining which vegetation types organisms perceive similarly and classifying these types into groups that function as similar habitats are necessary steps toward expanding the focus of conservation strategies from single species to ecosystems. Therefore, the methods used to determine these habitat classifications are crucial to the successful design and implementation of these conservation strategies. Typically, this process has been accomplished through best professional judgement. We used quantitative techniques to group vegetation types into habitats based on the occurrence of breeding wildlife species ( n = 420) in Oregon. After calculating faunal similarities among all regional vegetation types ( n = 130), we used cluster analysis to group vegetation types into wildlife habitats. We classified the original 130 vegetation types into 30 wildlife habitat types that we believe function similarly. We tested this classification to assess whether vegetation types could be correctly classified into habitat types based on wildlife species composition. Discriminant analysis correctly classified 95% of the vegetation types into their wildlife habitat types, strengthening our confidence in this approach. This approach for classifying habitat types allows consistent development of conservation strategies at coarse resolutions and aids in identifying vegetation types where additional biodiversity surveys are needed. Finally, this approach can be refined continuously as the precision of vegetation mapping and our understanding of organism-habitat associations improve.     

Environmental Surrogates for Predicting and Conserving Adaptive Genetic Variability in Tree Species

Abstract: Adaptive genetic variability within species is an essential component of biodiversity but has been largely ignored in studies aimed at assessing and predicting biodiversity of the forest environment. We used factorial regression and structuring models to test easily measured surrogates, such as ecological attributes, as predictors of adaptive genetic variation between populations of a tree species ( Eucalyptus delegatensis ). Adaptive variability was defined in terms of variation in average growth performance of 68 populations and of population-by-environment interaction across seven different environments. The best surrogates of genetic variability were measures of solar radiation and temperature range, each predicting more than 50% of the genetic variability within the species. Rock and understory types, when used either alone or in combination with other covariates, also were very efficient in discriminating between populations in groups showing similar adaptation. Significant relationships between particular surrogates and growth patterns of variation were attributed to effects of natural selection that had occurred in the population source locations. We recommend the development of studies focusing on the population level of biodiversity to improve the conservation of forest ecosystems in Australia.