Applying resource selection functions at multiple scales to prioritize habitat use by the endangered Cross River gorilla

2013 ◽  
Vol 19 (8) ◽  
pp. 943-954 ◽  
Author(s):  
Sarah C. Sawyer ◽  
Justin S. Brashares
2004 ◽  
Vol 61 (9) ◽  
pp. 1736-1746 ◽  
Author(s):  
Nicholas E Jones ◽  
William M Tonn

We developed resource selection functions (RSFs) for young-of-the-year (YOY) Arctic grayling (Thymallus arcticus) in a natural Barrenlands stream and used them to assess the habitat in an artificial stream created as part of a habitat compensation agreement in the Canadian Arctic. The model for small (15–21 mm) grayling explained 55% of the variation in habitat use and included water velocity, average water depth, and percentage of detritus and fines. The model for large (38–57 mm) grayling explained 36% of the variation in habitat use and included water depth, percentage of detritus and fines, and several cover variables. Model validation using a withheld sample of data indicated that the models provided good fits to the data, correctly classifying 71–75% of habitat-use locations. Applying the RSFs to observed habitat use in the artificial stream indicated an abundance of quality habitat for small grayling, but a paucity for the larger YOY. These results reflect an ontogenetic shift in habitat requirements, from the simple needs of small YOY to the more complex demands of larger YOY, demands that could not be well met by the artificial stream. We suggest that this inability contributed to the poor productive capacity of the artificial stream.


2007 ◽  
Vol 34 (2) ◽  
pp. 77 ◽  
Author(s):  
Erik Klop ◽  
Janneke van Goethem ◽  
Hans H. de Iongh

The preference of grazing herbivores to feed on grass regrowth following savanna fires rather than on unburnt grass swards is widely recognised. However, there is little information on which factors govern patterns of resource selection within burnt areas. In this study, we attempted to disentangle the effects of different habitat and grass sward characteristics on the utilisation of post-fire regrowth by nine species of ungulates in a fire-dominated woodland savanna in north Cameroon. We used resource-selection functions based on logistic regression. Overall, the resource-selection functions identified the time elapsed since burning as the most influential parameter in determining probability of use by ungulates, as most species strongly selected swards that were recently burned. This pattern might be related to nutrient levels in the grass sward. In addition, most species selected areas with high grass cover and avoided grass swards with high amounts of dead stem material. This is likely to increase bite mass and, hence, intake rates. The avoidance of high tree cover by some species may suggest selection for open areas with good visibility and, hence, reduced risk of predation. Body mass seemed to have no effect on differential selection of post-fire regrowth, irrespective of feeding style.


2010 ◽  
Vol 73 (3) ◽  
pp. 253-261 ◽  
Author(s):  
Ruth A. De Vere ◽  
Ymke Warren ◽  
Aaron Nicholas ◽  
Mary E. Mackenzie ◽  
James P. Higham

2015 ◽  
Vol 305 ◽  
pp. 10-21 ◽  
Author(s):  
Michel P. Laforge ◽  
Eric Vander Wal ◽  
Ryan K. Brook ◽  
Erin M. Bayne ◽  
Philip D. McLoughlin

2002 ◽  
Vol 157 (2-3) ◽  
pp. 281-300 ◽  
Author(s):  
Mark S Boyce ◽  
Pierre R Vernier ◽  
Scott E Nielsen ◽  
Fiona K.A Schmiegelow

Ecology ◽  
2009 ◽  
Vol 90 (12) ◽  
pp. 3554-3565 ◽  
Author(s):  
James D. Forester ◽  
Hae Kyung Im ◽  
Paul J. Rathouz

2015 ◽  
Vol 2 (2) ◽  
pp. 140423 ◽  
Author(s):  
Mimi Arandjelovic ◽  
Richard A. Bergl ◽  
Romanus Ikfuingei ◽  
Christopher Jameson ◽  
Megan Parker ◽  
...  

Population estimates using genetic capture–recapture methods from non-invasively collected wildlife samples are more accurate and precise than those obtained from traditional methods when detection and resampling rates are high. Recently, detection dogs have been increasingly used to find elusive species and their by-products. Here we compared the effectiveness of dog- and human-directed searches for Cross River gorilla ( Gorilla gorilla diehli ) faeces at two sites. The critically endangered Cross River gorilla inhabits a region of high biodiversity and endemism on the border between Nigeria and Cameroon. The rugged highland terrain and their cryptic behaviour make them difficult to study and a precise population size for the subspecies is still lacking. Dog-directed surveys located more fresh faeces with less bias than human-directed survey teams. This produced a more reliable population estimate, although of modest precision given the small scale of this pilot study. Unfortunately, the considerable costs associated with use of the United States-based detection dog teams make the use of these teams financially unfeasible for a larger, more comprehensive survey. To realize the full potential of dog-directed surveys and increase cost-effectiveness, we recommend basing dog-detection teams in the countries where they will operate and expanding the targets the dogs are trained to detect.


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