scholarly journals Fine-scale ecological and anthropogenic variables predict the habitat use and detectability of sloth bears in the Churia habitat of east Nepal

Author(s):  
Manoj Pokharel ◽  
Asmit Subba ◽  
Dipa Rai ◽  
Simrik Bhandari ◽  
Yadav Ghimire

Once widespread throughout the tropical forests of the Indian Subcontinent, the sloth bears have suffered a rapid range collapse and local extirpations in the recent decades. A significant portion of their current distribution range is situated outside of the protected areas (PAs). These unprotected sloth bear populations are under tremendous human pressures, but little is known about the patterns and determinants of their occurrence in most of these regions. The situation is more prevalent in Nepal where virtually no systematic information is available for sloth bears living outside of the PAs. We undertook a sign survey-based single-season occupancy study intending to overcome this information gap for the sloth bear populations residing in the Trijuga forest of southeast Nepal. Sloth bear sign detection/non-detection data and field-based covariates data were collected at the 74 randomly chosen 4-km2 grid cells using a varying number of 400m long transects in each grid cell. From our results, the model-averaged estimate of site use probability (ψ ± SE) was estimated to be 0.432 ± 0.039, which is a 13% increase from the naïve estimate (0.297) not accounting for imperfect detections of sloth bear signs. The presence of termite mounds and the distance to the nearest water source were the most important variables affecting the habitat use probability of sloth bears. The average site-level detectability (p ± SE) of sloth bear signs was estimated to be 0.195 ± 0.003 and was significantly determined by the index of human disturbances. We recommend considering the importance of fine-scale ecological and anthropogenic factors in predicting the sloth bear-habitat relationships across their range in the Churia habitat of Nepal.

2012 ◽  
Vol 72 (2) ◽  
pp. 216-227 ◽  
Author(s):  
Jennifer G. Chipault ◽  
Dean E. Biggins ◽  
James K. Detling ◽  
Dustin H. Long ◽  
Robin M. Reich

2020 ◽  
pp. 133-143
Author(s):  
Victoria J. Rowntree ◽  
Roger S. Payne ◽  
Donald M. Schell

Southern right whales (Eubalaena australis) have been studied on their nursery ground at Península Valdés, Argentina, every year since 1970. Since 1990, 1,208 individuals have been identified from photographs taken during annual aerial surveys; 618 whales were seen in two or more years. Patterns of habitat use have changed during the study in ways which suggest that right whales may be capable of substantial behavioral and ecological flexibility. One male and three females from Península Valdés have been sighted on other nursery grounds (Tristan da Cunha and southern Brazil). Three individuals from Península Valdés were sighted on feeding grounds off Shag Rocks and South Georgia. Some right whales from Península Valdés showed carbon and nitrogen isotope ratios very similar to those seen in right whales off South Africa, while others showed distinctive isotope ratios indicating that they fed in a different area. Whales of all ages and both sexes moved frequently between three major regions of concentration on the Península Valdés nursery ground. Subadults and adult females with calves were resighted at higher rates than adult males and females in non-calf years. Changes in the geographic distribution of whales at the Península include: (1) abandonment of a major region of concentration; (2) establishment of a nursery area adjacent to thecentre of a growing whalewatching industry; and (3) small-scale shifts in distribution, possibly in response to natural and human disturbances.


Oecologia ◽  
2018 ◽  
Vol 186 (3) ◽  
pp. 831-842 ◽  
Author(s):  
Casey A. Pennock ◽  
C. Nathan Cathcart ◽  
Skyler C. Hedden ◽  
Robert E. Weber ◽  
Keith B. Gido

1993 ◽  
Vol 9 (3) ◽  
pp. 339-348 ◽  
Author(s):  
Martin Fisher

ABSTRACTDescriptions of the fine scale distribution of organisms have frequently been used to investigate various ecological phenomena. Unfortunately, the most widely used spatial analysis techniques are based on single index statistics, which convey only minimal information about the biological processes underlying the studied distributions. Such statistics cannot detect changes in pattern over different scales, and cannot identify some types of distribution. Additionally, both the use of such statistics on the distribution of individuals which have a non-negligible size, and the frequent failure to use an edge correction for points close to the boundaries of a sampled area, have led to the over-reporting of ‘spaced out’ (‘regular’) distributions. Using two spatial distributions recently analysed with a single index statistic (termite mounds, and earthmounds created by termites), I illustrate the benefits gained from using the spatial functions K(t), G(y) and F(x) to analyse both ‘point events’ and events which have a non-negligible size. These functions are considerably more informative about the nature of a spatial pattern and offer wide scope for the fitting of spatial models to biological distributions.


2017 ◽  
Vol 141 ◽  
pp. 224-236 ◽  
Author(s):  
Candice Michelot ◽  
David Pinaud ◽  
Matthieu Fortin ◽  
Philippe Maes ◽  
Benjamin Callard ◽  
...  

2015 ◽  
Vol 28 ◽  
pp. 9-17
Author(s):  
Dinesh Ghimire ◽  
Tej Bahadur Thapa

Effective conservation of Sloth bear requires detailed information regarding their distribution and habitat use. This study attempted to generate baseline data on distribution and habitat preference of Sloth Bear in Chitwan National Park, Nepal during March–May 2012. The study area was divided into 74 grids each measuring 16 Km2. Of the total grids, 35 were randomly selected for occupancy sampling. A total of 288 spatial replicates were sampled in 35 different grids recording 87 direct or indirect evidences of Sloth bear. Among them, 50 diggings, 25 scats, four scrapes with live animals in eight points were detected in four different habitat types of the Park. The variance to mean ratio showed clumped distribution of Sloth bear. The RPI values revealed that the mixed forest was found to be most preferred (RPI = 0.42) by Sloth Bear followed by grassland (RPI = 0.21). Riverine forest and Sal forest were less preferred (RPI = -0.25 and -0.11 respectively) but not avoided. Distribution of Sloth bear was influenced by distance to nearest water sources, distance to road and altitude. Similarly, disturbances like human activities, presence of cattle and fi re were found to affect the distribution of Sloth bear.J. Nat. Hist. Mus. Vol. 28, 2014: 9-17


2009 ◽  
Vol 87 (5) ◽  
pp. 422-432 ◽  
Author(s):  
D. Gallant ◽  
L. Vasseur ◽  
M. Dumond ◽  
E. Tremblay ◽  
C. H. Bérubé

Habitat preferences of river otters ( Lontra canadensis (Schreber, 1777)) are well known, but because most studies were conducted in regions with markedly low or high levels of anthropogenic disturbances, it is not well known how their habitat usage is affected by varied anthropogenic disturbances and land-use regimes on a regional scale. We studied habitat use by otters in eastern New Brunswick, Canada, in an area having both protected and disturbed riparian habitats. Using long-range winter riparian transects, we documented activity-sign distribution along riverbanks in relation to 12 habitat factors and 9 categories of anthropogenic disturbances. We documented variables at site with activity signs and at habitat stations along riverbanks at 500 m intervals. We used logistical regressions and Akaike’s information criterion in an information–theoretic approach to compare models and determine the important factors involved. Habitat-related factors were more important than anthropogenic ones in describing habitat use. The best performing models were those incorporating both habitat and anthropogenic factors. Beaver ( Castor canadensis Kuhl, 1820) ponds were the most important habitat factor, while fields were the most important anthropogenic factor. Our results indicate that otters responded mostly to the presence of habitat features they use and secondarily to the presence of anthropogenic structures or activities in an area.


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