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550 records · Page 31Linked to original sources
USGS1987

Habitat Suitability Index Models: Black Bear, Upper Great Lakes Region

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the black bear (Ursus americanus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

FWS/OBS↗
USGS2004

Importance of salmon to wildlife: Implications for integrated management

Salmon ( Oncorhynchuss pp.) are an important resource for terrestrial wildlife. However, the salmon requirements of wildlife populations and the role wildlife play in nutrient transport across ecosystems are largely ignored in salmon and habitat management. Any activity that reduces the availability of or access to salmon by wildlife may adversely affect wildlife populations and, potentially, ecosystem-level processes. Thus, when the conservation of specific wildlife populations or healthy ecosystems is the management objective, allocation of salmon to wildlife should be considered. We provide an example of how such allocations could be calculated for a hypothetical bear population. Ultimately, salmon allocation for wildlife calls for integrated management of natural resources across agencies, across species, and across ecosystems. We summarize the current state of knowledge relative to the interaction between Pacific salmon and the terrestrial ecosystem , with special emphasis on the import of salmon to terrestrial wildlife and the import of wildlife to terrestrial and aquatic ecosystems

Ursus↗
USGS2005

Delineating priority habitat areas for the conservation of Andean bears in northern Ecuador

We sought to identify priority areas for the conservation of Andean bear (Tremarctos ornatus) habitat in the northern portion of the eastern Andean cordillera in Ecuador. The study area included pa??ramo and montane forest habitats within the Antisana and Cayambe-Coca ecological reserves, and unprotected areas north of these reserves with elevations ranging from 1,800 to 4,300 m. We collected data on bear occurrence along 53 transects during 2000-01 in the Oyacachi River basin, an area of indigenous communities within the Cayambe-Coca Ecological Reserve. We used those data and a set of 7 environmental variables to predict suitability of Andean bear habitat using Mahalanobis distance, a multivariate measure of dissimilarity. The Mahalanobis distance values were classified into 5 classes of habitat suitability and generalized to a resolution of 1,650-m ?? 1,650-m grid cells. Clusters of grid cells with high suitability values were delineated from the generalized model and denned as important habitat areas (IHAs) for conservation. The IHAs were ranked using a weighted index that included factors of elevation range, influence from disturbed areas, and current conservation status. We identified 12 IHAs, which were mainly associated with pa??ramo and cloud forest habitats; 2 of these areas have high conservation priorities because they are outside existing reserves and close to areas of human pressure. The distribution of the IHAs highlighted the role of human land use as the main source of fragmentation of Andean bear habitat in this region, emphasizing the importance of preserving habitat connectivity to allow the seasonal movements among habitat types that we documented for this species. Furthermore, the existence of areas with high habitat suitability close to areas of intense human use indicates the importance of bear-human conflict management as a critical Andean bear conservation strategy. We suggest that a promising conservation opportunity for this species is linked to its occurrence in highland habitats, which play a key role in the maintenance of long-term water supplies.

Ursus↗
USGS2007

Sub-sampling genetic data to estimate black bear population size: A case study

Costs for genetic analysis of hair samples collected for individual identification of bears average approximately US$50 [2004] per sample. This can easily exceed budgetary allowances for large-scale studies or studies of high-density bear populations. We used 2 genetic datasets from 2 areas in the southeastern United States to explore how reducing costs of analysis by sub-sampling affected precision and accuracy of resulting population estimates. We used several sub-sampling scenarios to create subsets of the full datasets and compared summary statistics, population estimates, and precision of estimates generated from these subsets to estimates generated from the complete datasets. Our results suggested that bias and precision of estimates improved as the proportion of total samples used increased, and heterogeneity models (e.g., M h [ C hao] ) were more robust to reduced sample sizes than other models (e.g., behavior models). We recommend that only high-quality samples (>5 hair follicles) be used when budgets are constrained, and efforts should be made to maximize capture and recapture rates in the field.

southeastern United States↗
USGS2017

Use of spatial capture–recapture to estimate density of Andean bears in northern Ecuador

The Andean bear ( Tremarctos ornatus ) is the only extant species of bear in South America and is considered threatened across its range and endangered in Ecuador. Habitat loss and fragmentation is considered a critical threat to the species, and there is a lack of knowledge regarding its distribution and abundance. The species is thought to occur at low densities, making field studies designed to estimate abundance or density challenging. We conducted a pilot camera-trap study to estimate Andean bear density in a recently identified population of Andean bears northwest of Quito, Ecuador, during 2012. We compared 12 candidate spatial capture–recapture models including covariates on encounter probability and density and estimated a density of 7.45 bears/100 km 2 within the region. In addition, we estimated that approximately 40 bears used a recently named Andean bear corridor established by the Secretary of Environment, and we produced a density map for this area. Use of a rub-post with vanilla scent attractant allowed us to capture numerous photographs for each event, improving our ability to identify individual bears by unique facial markings. This study provides the first empirically derived density estimate for Andean bears in Ecuador and should provide direction for future landscape-scale studies interested in conservation initiatives requiring spatially explicit estimates of density.

Ursus↗
USGS2010

A proposed lexicon of terms and concepts for human-bear management in North America

We believe that communication within and among agency personnel in the United States and Canada about the successes and failures of their human–bear (Ursidae) management programs will increase the effectiveness of these programs and of bear research. To communicate more effectively, we suggest agencies clearly define terms and concepts used in human–bear management and use them in a consistent manner. We constructed a human–bear management lexicon of terms and concepts using a modified Delphi method to provide a resource that facilitates more effective communication among human–bear management agencies. Specifically, we defined 40 terms and concepts in human–bear management and suggest definitions based on discussions with 13 other professionals from the United States and Canada. Although new terms and concepts will emerge in the future and definitions will evolve as we learn more about bear behavior and ecology, our purpose is to suggest working definitions for terms and concepts to help guide human–bear management and research activities in North America. Applications or revisions of these definitions may be useful outside of North America.

Ursus↗
USGS2012

Assessing sloth bears as surrogates for carnivore conservation in Sri Lanka

Bears are large, charismatic mammals whose presence often garners conservation attention. Because healthy bear populations typically require large, contiguous areas of habitat, land conservation actions often are assumed to benefit co-occurring species, including other mammalian carnivores. However, we are not aware of an empirical test of this assumption. We used remote camera data from 2 national parks in Sri Lanka to test the hypothesis that the frequency of detection of sloth bears (Melursus ursinus) is associated with greater richness of carnivore species. We focused on mammalian carnivores because they play a pivotal role in the stability of ecological communities and are among Sri Lanka's most endangered species. Seven of Sri Lanka's carnivores are listed as endangered, vulnerable, or near threatened, and little empirical information exists on their status and distribution. During 2002–03, we placed camera traps at 152 sites to document carnivore species presence. We used Poisson regression to develop predictive models for 3 categories of dependent variables: species richness of (1) all carnivores, (2) carnivores considered at risk, and (3) carnivores of least conservation concern. For each category, we analyzed 8 a priori models based on combinations of sloth bear detections, sample year, and study area and used Akaike's information criterion (AIC c ) to test our research hypothesis. We detected sloth bears at 55 camera sites and detected 13 of Sri Lanka's 14 Carnivora species. Species richness of all carnivores showed positive associations with the number of sloth bear detections, regardless of study area. Sloth bear detections were also positively associated with species richness of carnivores at risk across both study years and study areas, but not with species richness of common carnivores. Sloth bears may serve as a valuable surrogate species whose habitat protection would contribute to conservation of other carnivores in Sri Lanka.

Ursus↗
USGS2020

An evaluation of noninvasive sampling techniques for Malayan sun bears

Traditional mark–recapture studies to estimate abundance and trends of Malayan sun bear ( Helarctos malayanus ) populations are impeded by logistics of live-trapping wild individuals. The development of noninvasive sampling techniques for monitoring sun bear populations is therefore crucial for targeted conservation action. Sun bears have short fur, and conventional hair-snagging devices are ineffective. Moreover, scats are rapidly decomposed by the warm, humid environment, as well as by invertebrates. In combination with camera-sampling, we tested 2 designs of hair traps ( n = 45) in situ at Tabin Wildlife Reserve in Sabah, Malaysia, during April–October 2017, to obtain hair samples from wild sun bears. We also deployed 4 types of hair traps in rainforest enclosures with captive sun bears to evaluate hair-capture success and the effects of weathering, lure, and adhesive on polymerase chain reaction (PCR) amplification success. Wild adult male sun bears displayed back-rubbing behavior at hair traps and 6 individuals were identified based on unique chest marks. We collected 30 hair samples from wild sun bears, including 15 chest mark images of 6 individuals over 1,260 trap-nights. We detected adult males at hair traps more frequently than females and subadults. We obtained 39 hair samples in the captive trials. Extracted DNA from hair roots successfully amplified with mitochondrial (wild bears: 95%; captive bears: 97%) and microsatellite primers (wild bears: 100%; captive bears 87%). Adhesive and lure type did not affect PCR amplification, but weathering reduced amplification of microsatellite loci. This study is the first successful attempt to obtain genetic samples from wild sun bears using inexpensive, readily available materials such as duct tape, polybutyl glue, and locally sourced lures. The quality of genetic material from these genetic samples should be suitable for studies of population size and gene flow.

Sabah↗