The only available data are the following: perpendicular distance of the fecal patch from the transect, map data (coordinates and elevation of the area where the fecal patches were found), and sample survey data. Note: Fecal samples not collected so disregard genetic fingerprinting.
Hi Gen-
I definitely second Aaron's recommended reading. Unless you have some exclusion criteria based on condition of the feces, you might look into assessing decay rates as well or else you miss a temporal aspect that could seriously bias your results (e.g. did one individual defecate in the area 100 times over months or did a hundred individuals just pass through and all defecate recently?). Various studies have looked at that and you might find some useful methodology in the lit...but that said, tropical systems can be notoriously difficult for this aspect.
Hi Gen,
You can use line transect sampling in order to get a good estimate of density of fecal counts. This would give you an index of relative abundance of the animal assuming defecation rates are similar across time, space, between sexes, within ages. You could justify, based on the data, that if you find 10 fecal groups in one area, and 5 in another, that the first has double the relative abundance. Assuming equal detection rates between areas.
Here is some recommended reading:
Burnham, K. P., & Anderson, D. R. (1984). The Need for Distance Data in Transect Counts. The Journal of Wildlife Management, 48(4), 1248–1254. doi:10.2307/3801785
Krebs, C.J. 1989. Ecological Methodology. Harper and Row Publishers, New York. 654 pp *** Pages113-121
Neff, D. J. (1968). The Pellet-Group Count Technique for Big Game Trend, Census, and Distribution: A Review. The Journal of Wildlife Management, 32(3), 597–614. doi:10.2307/3798941
White, G. C., & Eberhardt, L. E. (1980). Statistical analysis of deer and elk pellet-group data. The Journal of Wildlife Management, 121–131.
Hi Gen-
I definitely second Aaron's recommended reading. Unless you have some exclusion criteria based on condition of the feces, you might look into assessing decay rates as well or else you miss a temporal aspect that could seriously bias your results (e.g. did one individual defecate in the area 100 times over months or did a hundred individuals just pass through and all defecate recently?). Various studies have looked at that and you might find some useful methodology in the lit...but that said, tropical systems can be notoriously difficult for this aspect.
Thanks Aaron and Jason! In fact, we did line transect sampling but forgot to note the number of fecal groups within a cluster. We just classified the feces whether they were splattered, in fragments, or intact (whole). My colleague also gave rough estimates of the number of individuals that probably defecated in the area.
I was also considering to exclude the condition of the feces since there are no available literature on the defecation rate of long-tailed macaques (Macaca fascicularis philippensis) and the decay rate of their feces in a tropical setting.
I agree with Jasons comments about incorporating distance sampling elements. Not only could you get one individual doing all the defecating, but you could also get diffences between habitats/sites with differential defecation rates at each. I'd avoid invalidated indices at all costs - http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12250/abstract;jsessionid=2DC70A8E8143F31F1C86515A3A7DE758.f02t04?deniedAccessCustomisedMessage=&userIsAuthenticated=false
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