Effects of water availability and habitat quality on bark-stripping behavior in Barbary Macaques

The cedar oak forest of the Middle Atlas in Morocco is not only the last of the large forests in the southern Mediterranean, but it also contains all the surviving forest biodiversity. This forest has been severely affected b y drought, overgrazing by mixed herds of goat and sheep, and excessive logg ing for timber, firewood, and livestock fodder. Recently, cedar bark stripp ing by Barbary Macaques (Macaca sylvanus) has begun to have an effect on th e forest. We investigated this behavior by monitoring a 500-km(2) mosaic fo rest of cedar and oak in the Middle Atlas of Morocco between 1994 and 1996. We surveyed the forest 18 times in four different seasons along a 90-km tr ansect. We recorded observations of bark stripping and a variety of quantit ative ecological factors that could predict this behavior, such as livestoc k density, forest quality, under-growth condition, water availability, and monkey density. The statistical analysis (including rank correlation, regre ssion, and nonparametric variance analysis) strongly suggests that water sc arcity and monkey exclusion from previously available permanent water sourc es are correlated with intense cedar bark-stripping behavior by macaques. T he density of cedars and of monkeys appeared to be only secondary factors. As a conservation policy, making water more accessible to wild monkeys migh t reduce bark-stripping behavior.