Estimating decay rates of elephant dung piles in forest

Barnes, R. F. W.; Barnes, Keith

doi:10.1111/j.1365-2028.1992.tb00508.x

Cited by 47 publications

(41 citation statements)

References 6 publications

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“…We dummy coded the variable tree species and used a multimodel selection approach [Johnson & Omland, 2004], thus we built a set of alternative hypotheses based on all the variables and a constant. The constant model was similar to the exponential decay described in fecal decay rate studies in which time is treated as continuous [Barnes & Barnes, 1992. But, we treated decay as a first-order Markov process with discrete daily steps [Walsh & White, 2005].…”

Section: Modeling Nest Decay: Factors Affecting Nest Decay and Lifetimentioning

confidence: 99%

Estimating chimpanzee population size with nest counts: validating methods in Taï National Park

Kouakou

Boesch

Kuehl

2009

American J Primatol

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Successful conservation and management of wild animals require reliable estimates of their population size. Ape surveys almost always rely on counts of sleeping nests, as the animals occur at low densities and visibility is low in tropical forests. The reliability of standing-crop nest counts and marked-nest counts, the most widely used methods, has not been tested on populations of known size. Therefore, the answer to the question of which method is more appropriate for surveying chimpanzee population remains problematic and comparisons among sites are difficult. This study aimed to test the validity of these two methods by comparing their estimates to the known population size of three habituated chimpanzee communities in Taï National Park [Boesch et al., Am J Phys Anthropol 130:103-115, 2006; Boesch et al., Am J Primatol 70:519-532, 2008]. In addition to transect surveys, we made observations on nest production rate and nest lifetime. Taï chimpanzees built 1.143 nests per day. The mean nest lifetime of 141 fresh nests was 91.22 days. Estimate precision for the two methods did not differ considerably (difference of coefficient of variation <5%). The estimate of mean nest decay time was more precise (CV=6.46%) when we used covariates (tree species, rainfall, nest height and age) to model nest decay rate, than when we took a simple mean of nest decay times (CV=9.17%). The two survey methods produced point estimates of chimpanzee abundance that were similar and reliable: i.e. for both methods the true chimpanzee abundance was included within the 95% estimate confidence interval. We recommend further research on covariate modeling of nest decay times as one way to improve the precision and to reduce the costs of conducting nest surveys.

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Section: Modeling Nest Decay: Factors Affecting Nest Decay and Lifetimentioning

confidence: 99%

Estimating chimpanzee population size with nest counts: validating methods in Taï National Park

Kouakou

Boesch

Kuehl

2009

American J Primatol

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“…Most of our knowledge on the ecology and behavior of African elephants comes from studies of L. africana (Douglas-Hamilton and Douglas-Hamilton, 1975;Moss, 1988;Poole and Moss, 1981;Sikes, 1971). Only recently has some information become available on L. cyclotis (Barnes and Barnes, 1992;Fay and Agnagna, 1991;Turkalo, 1996), and this has recently been highlighted by Tangley (1997). The FAE is much more of a browser and frugivore than the BAE; it lives in much smaller social groups, and it communicates with very low frequency calls, as low as 5 hertz (Tangley, 1997), well below the 14-24 hertz reported for Asian elephants (Payne et al, 1986) and for BAEs (Langbauer et al, 1991).…”

Section: Elephantmentioning

confidence: 99%

Living African elephants belong to two species: Loxodonta africana (Blumenbach, 1797) and Loxodonta cyclotis (Matschie, 1900)

Grubb¹,

Groves

Dudley

et al. 2000

Elephant

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“…If dung piles decay during count intervals, the formula should incorporate an estimated dung decay rate (e.g. Barnes and Barnes 1992), and because decay rates may change among seasons and habitats, temporal or spatial comparisons of abundance should be done with caution (Rabinowitz 1993).…”

Section: Estimation Of Deer Abundance By Pellet-group Countsmentioning

confidence: 99%

Estimating brocket deer (Mazama gouazoubira and M. americana) abundance by dung pellet counts and other indices in seasonal Chiquitano forest habitats of Santa Cruz, Bolivia

2004

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We assessed dung and track counts for indexing brocket deer abundance in seasonal habitats on a ranch where hunting is not practiced in the Bolivian lowlands. Surveys were replicated along four 10-km trails (totaling 180 km in the wet season and 90 km in the dry season) through four semideciduous forest habitats. Dung pellets and tracks were identified as belonging to Mazama gouazoubira or M. americana by size and shape. Pellet groups lasted more than 1 month during the dry season, but decayed within 1-2 weeks in the wet season. Mean density estimates based on dung counts varied widely between seasons for gray brockets (from 6.77±4.0 to 30.57±23.5 ind/km 2 ; mean±SD) but not for reds (from 3.52±4.6 to 6.98±7.2 ind/km 2 ). These values were probably too high due to underestimation of daily deposition rate, and were reduced during the wet season because of dung decay. We found consistently more dung in the dry season and more tracks in the wet season. Sightings of red brockets were too few for line-transect analysis (n=6), but those of gray brockets (n=42) produced an overall estimate of 5.6 ind/km 2 (95% CI=3.5-9.0 ind/km 2 ). Different estimates indicated that gray brockets were more abundant than reds in all situations, except perhaps in the riverine forest. Environmental factors affected these indices of abundance differently, and while we recommend the use of dung counts in dry-season scenarios, we think that index reliability should be assessed locally before conducting population comparisons.

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Estimating decay rates of elephant dung piles in forest

Cited by 47 publications

References 6 publications

Estimating chimpanzee population size with nest counts: validating methods in Taï National Park

Estimating chimpanzee population size with nest counts: validating methods in Taï National Park

Living African elephants belong to two species: Loxodonta africana (Blumenbach, 1797) and Loxodonta cyclotis (Matschie, 1900)

Estimating brocket deer (Mazama gouazoubira and M. americana) abundance by dung pellet counts and other indices in seasonal Chiquitano forest habitats of Santa Cruz, Bolivia

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