Simple measurements of forest antelope dung pellets are not enough for species identification

Published: 16 May 2013

Simple measurements of forest antelope dung pellets are not enough for species identification Scientists based in Devon and Tanzania have used DNA from dung to show that a survey method for threatened forest antelope species is unreliable when multiple species co-exist in the same area. African forest antelope, such as the Endangered Abbott’s duiker, are often difficult to survey as they can be shy, solitary and nocturnal but their faecal deposits (dung piles) are relatively easily found. Previous research by WWCT and colleagues has shown that identifying dung in the field is often inaccurate in forests with more than one species of antelope because the dung pellets of different antelopes are similar in appearance and may overlap in size (Bowkett et al. 2009). New research published online early in Conservation Genetics Resources took this search for a simple field test to identify antelope dung one step further by testing how accurately dung piles can be statistically assigned to species based on pellet size. WWCT’s Andy Bowkett spent over 10 months in Tanzania between 2006 and 2009 collecting dung samples for his research into duiker genetics. With additional samples from Trevor Jones of Anglia Ruskin University, Andy and field researcher Richard Laizzer spent many hours measuring a total of 238 dung piles with fine-scale callipers (> 4,600 individual pellets). The samples were then exported to the Molecular Ecology and Evolution lab led by Dr Jamie Stevens at the University of Exeter where the true origin of each dung sample was verified by extracting DNA and matching the resulting sequences to known reference samples. The results showed that the pellets of each antelope overlapped in size with those of at least one other species and that statistically grouping dung piles on the basis of pellet length correctly predicted species in only 59% of cases. Although there were many dung characteristics that were not measured during this survey, such as surface texture, colour or smell, the authors of the research concluded that simple field measurements are not generally useful in situations where multiple antelope species are found in the same forest. Alternative survey methods such as the DNA identification used to verify species in this study or automatic camera-traps may be required for species-specific monitoring of forest antelope populations. Although these technological methods require significant scientific and financial resources such investment may well be necessary in the case of globally threatened species such as Abbott’s duiker.

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