The Moroccan government wants to move the largest remaining population of Barbary macaques because they are stripping bark off cedars, which can kill the trees. But this plan would needlessly endanger these monkeys. There is a way to save the cedars without harming macaques, according to new research in the February issue of Conservation Biology.
“This is a battle for conservation — if the macaques are moved, they are destined to complete extinction,” says Andrea Camperio Ciani of the University of Padova in Italy.
Morocco’s Middle Atlas cedar forest is the last suitable habitat for the Barbary macaque, which is listed as vulnerable by the World Conservation Union; roughly 10,000 of the 25-pound monkeys live there. The forest has been undergoing desertification due primarily to overgrazing, wood cutting, and, in the last decade, drought. Recently, the forest’s degradation has been exacerbated by a dramatic increase in the macaques’ cedar bark stripping.
The Moroccan Department of Waters and Forests blames this severe bark stripping on what it believes to be an increase in the macaques’ population density. Accordingly, Moroccan authorities plan to capture and move macaques to habitats without cedars. However, the macaques need the cedars: the monkeys flee up these tall trees when attacked by dogs or jackals, and they eat young cedar leaves during the winter when snow covers the undergrowth where they usually forage.
Camperio Ciani and his colleagues question this plan for two reasons. First, mass relocation would probably kill many of the macaques. Second, the researchers disagree with the basic assumption underlying the plan. They have determined that far from increasing, the density of the macaque population has actually decreased by about 40 percent in the last 20 years.
The belief that the macaques are increasing is based on the fact that more of them are seen along roads and in core areas of the forest. But this does not mean there are more macaques, says Camperio Ciani. “Actually, the remaining monkeys are abandoning the already degraded areas and are progressively converging on the few still suitable forests. Imagine the “Titanic” scene: when the boat is sinking the surviving passengers crowd the still floating areas, but you would never say that they were increasing!” he says.
To figure out why the macaques are stripping cedar bark, Ciani and colleagues considered a variety of factors including macaque density, livestock density (overgrazing could force the monkeys to forage in the trees), and water availability (shepherds have been enclosing forest water sources with cement wells, which makes it easier to extract water for livestock but keeps wildlife from reaching the water).
The researchers found that water availability correlated best with bark stripping. The macaques stripped hardly any bark in areas where water was readily available, such as Lake Wiwane, which is one of the few permanent water sources in the study area. Moreover, macaques stripped bark intensely in areas where water was scarce or where the monkeys were excluded from previously available water sources.
Because these results suggest that macaques strip cedar bark for its water, Camperio Ciani and his colleagues recommend making water more accessible to the monkeys. This would be easy to do: for instance, macaques could use ladders to reach the water in cement wells. The researchers’ plan has the added benefit of being cheaper than relocating the macaques. This study underscores the importance of basing conservation decisions on sound information rather than on jumping to conclusions.
Camperio Ciani’s co-authors are Loredana Martinoli and Claudio Capiluppi, both with the University of Padova in Italy, and Mohamed Arahou and Mohamed Mouna, both of the Institute Scientifique, Universit? Mohammed V in Rabat, Morocco.
Camperio Ciani, A., L. Martinoli, C. Capiluppi, M. Arahou, and M. Mouna. 2001. Effects of water availability and habitat quality on bark-stripping behavior in barbary macaques. Conservation Biology 15(1):259-265.