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Our understanding of animal habitat requirements are generally based on location data. We assume that those types of vegetation in which an organism is consistently found represent important habitat. In many cases, location data are... more
Our understanding of animal habitat requirements are generally based on location data. We assume that those types of vegetation in which an organism is consistently found represent important habitat. In many cases, location data are collected independently from vegetation data, and the two are combined by overlaying the points representing animal locations onto a vegetation map. The number of points that occur in each type are counted, and these proportions are compared with random expectations to infer habitat selection (Neu et al. 1974; Alldredge and Ratti 1986). This process would be fairly straightforward if the uncertainties were limited to sampling error; however, there is always additional error associated with this process: Neither the coordinates of the animal locations nor the classification of vegetation mapped at those locations are error free.
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... more
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.
Pikas (Ochotona Link, 1795) are high‐altitude specialist species making them a useful bioindicator species to warming in high‐altitude ecosystem. The Himalayan Mountains are an important part of their range, supporting approximately... more
Pikas (Ochotona Link, 1795) are high‐altitude specialist species making them a useful bioindicator species to warming in high‐altitude ecosystem. The Himalayan Mountains are an important part of their range, supporting approximately 23%–25% of total pika species worldwide, yet we lack basic information on the distribution patterns. We combine field‐based surveys with genetics‐based identification and phylogeny to identify differences in species‐environment relationships. Further, we suggest putative evolutionary causes for the observed niche patterns.LocationHimalayan high‐altitude region.MethodsWe sampled 11 altitudinal transects (ranging from ~2,000 to 5,000 m) in the Himalaya to establish occurrence records. We collected 223 species records using genetic analyses to confirm species' identity (based on some invasive and mostly noninvasive biological samples). Niche and geographic overlap were estimated using kernel density estimates.ResultsMost pikas in the Himalaya span wide ...
All Treesearch publications were written or produced by Forest Service personnel and are in the public domain. ... Source: Pages 424-450 in: Kareiva, PM; Kingsolver, JG; Huey, RB, comps., eds. Biotic Interactions and Global Change.... more
All Treesearch publications were written or produced by Forest Service personnel and are in the public domain. ... Source: Pages 424-450 in: Kareiva, PM; Kingsolver, JG; Huey, RB, comps., eds. Biotic Interactions and Global Change. Sunderland, Massachuseets: ...
▪   Official conservation efforts for the northern spotted owl began in the United States in 1975 when it was declared “threatened” in the state of Oregon; efforts continued in a sporadic and unsystematic way through the 1980s. In 1989... more
▪   Official conservation efforts for the northern spotted owl began in the United States in 1975 when it was declared “threatened” in the state of Oregon; efforts continued in a sporadic and unsystematic way through the 1980s. In 1989 the Interagency Scientific Committee (ISC) was established by Congress and charged with the development of a scientifically defensible conservation strategy covering the entire range of the northern spotted owl, which includes parts of the states of Oregon, Washington, and California. The ISC collated all spotted owl research and approached questions concerning the need for a conservation strategy and the efficacy of potential reserve designs as testable hypotheses. Because the hypothesis tests were based on incomplete data and highly stylized population models, uncertainty concerning the conclusions of the ISC remained. Subsequent research focused on answering those uncertainties, and here we revisit the ISC's conclusions, asking which if any of ...
Release of a proposed conservation strategy for the northern spotted owl in April of 1990 (Thomas et al. 1990) raised concern in Region 5 (R5) of the U.S. Department of Agriculture, Forest Service (FS) about the adequacy of their regional... more
Release of a proposed conservation strategy for the northern spotted owl in April of 1990 (Thomas et al. 1990) raised concern in Region 5 (R5) of the U.S. Department of Agriculture, Forest Service (FS) about the adequacy of their regional guides for managing the California spotted owl (Barker and Jay pers. comm.). This concern was amplified by a decision formally announced on 26 June 1990 by the U. S. Department of Interior, Fish and Wildlife Service (1990) to confer "threatened " status on the northern spotted owl throughout its range. Negotiations began shortly thereafter to undertake an assessment of the current status of the California subspecies. This process led to the formation
Knowledge of scientific methods is not always enough in conservation management. Political pressures, legal proceedings, and policy decisions often dictate success or failure in a management scheme. The Spotted Owl epitomizes the... more
Knowledge of scientific methods is not always enough in conservation management. Political pressures, legal proceedings, and policy decisions often dictate success or failure in a management scheme. The Spotted Owl epitomizes the high-visibility struggle that sometimes ensues when protec tive legislation restricts use of a resource. Success or failure in management often is determined by skills other than ecological knowledge.
7 A Common Framework for Conservation Planning: Linking Individual and Metapopulation Models Barry R Noon and Kevin S. McKelvey Many populations exhibit pronounced spatial structure: dispersed areas of high population density embedded in... more
7 A Common Framework for Conservation Planning: Linking Individual and Metapopulation Models Barry R Noon and Kevin S. McKelvey Many populations exhibit pronounced spatial structure: dispersed areas of high population density embedded in areas of low density, ...
Small carnivore abundance from track plot, camera-trap, and spot-lighting surveys were compared between a contiguous tract of tropical rainforest and 10 rainforest fragments in the southern Western Ghats, India. Although six species were... more
Small carnivore abundance from track plot, camera-trap, and spot-lighting surveys were compared between a contiguous tract of tropical rainforest and 10 rainforest fragments in the southern Western Ghats, India. Although six species were recorded from the rainforests in this region, surveys targeted three nocturnal species. Small carnivore abundance was higher in contiguous rainforests, especially the endemic Brown Palm Civet Paradoxurus jerdoni, whose occurrence was positively infl uenced by food-tree densities and altitude, and was higher in medium-sized (51–100 ha) fragments adjoining shade-coffee plantations than the more isolated smaller and larger fragments. The omnivorous and widespread Small Indian Civet Viverricula indica and mongooses Herpestes spp. were more frequent in rainforest fragments than in the relatively undisturbed, large, contiguous tract of rainforest in Kalakad–Mundanthurai Tiger Reserve. Thus, small carnivores persist in fragmented landscapes with altered co...
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