Effects of Water Availability and Habitat Quality on Bark‐Stripping Behavior in Barbary Macaques

Abstract

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 by drought, overgrazing by mixed herds of goat and sheep, and excessive logging for timber, firewood, and livestock fodder. Recently, cedar bark stripping by Barbary Macaques ( Macaca sylvanus ) has begun to have an effect on the forest. We investigated this behavior by monitoring a 500-km 2 mosaic forest of cedar and oak in the Middle Atlas of Morocco between 1994 and1996. We surveyed the forest 18 times in four different seasons along a 90-km transect. We recorded observations of bark stripping and a variety of quantitative ecological factors that could predict this behavior, such as livestock density, forest quality, undergrowth condition, water availability, and monkey density. The statistical analysis (including rank correlation, regression, and nonparametric variance analysis) strongly suggests that water scarcity and monkey exclusion from previously available permanent water sources are correlated with intense cedar bark-stripping behavior by macaques. The density of cedars and of monkeys appeared to be only secondary factors. As a conservation policy, making water more accessible to wild monkeys might reduce bark-stripping behavior.Efectos de la Disponibilidad de Agua y la Calidad del Hábitat en la Conducta Descortezadora del Macaco de Barbary Resumen: El bosque de cedro y roble del Atlas medio de Marruecos no es solamente el último de los bosques grandes del sur del Mediterráneo, sino que también contiene toda la biodiversidad sobreviviente del bosque. Este bosque ha sido severamente afectado por sequías, sobrepastoreo por rebaños de cabras y ovejas, y una tala excesiva para la extracción de madera, leña y forraje para el ganado. Recientemente, el descortezado de árboles de cedro por el macaco de Barbary ( Macaca sylvanus ) ha empezado a tener un efecto en el bosque. Nosotros investigamos esta conducta monitoreando un mosaico de 500-km 2 del bosque de cedro y roble en el Atlas medio de Marruecos entre 1994 y 1996. Hicimos un relevamiento del bosque 18 veces en cuatro estaciones diferentes a lo largo de 90 km de transectos. Realizamos observaciones de descortezado y una variedad de factores ecológicos cuantitativos y cualitativos que podrían predecir esta conducta, tales como, densidad, calidad del bosque, disponibilidad de agua y densidad de monos. El análisis estadístico (que incluyó un análisis de correlación, de regresión y un análisis de varianza no paramétrico) sugiere de manera contundente que la escasez de agua y la exclusión de monos de fuentes de agua previamente disponibles son eventos que están correlacionados con una actividad intensa de descortezado del cedro por los macacos. La densidad de cedros y la densidad de monos parecen ser solo factores secundarios. Como una medida de conservación, facilitar el acceso a fuentes de agua para los monos, podría reducir la conducta d...

Increasing Drought Sensitivity and Decline of Atlas Cedar (Cedrus atlantica) in the Moroccan Middle Atlas Forests

“…Climatic stress influences tree physiological status and may determine whether a tree can withstand, for instance, severe defoliations or bark stripping by Barbary Macaques. In turn, climate change appears to exert a significant effect on herbivore behavior [42,62]. Recently, cedar bark stripping by Barbary Macaques appears to have increased the incidence of decline in some Atlas cedar forests [62].…”

“…In addition to these hypothesized climate-driven factors, human perturbation by overgrazing, logging, pruning of lower branches for livestock winter fodder and firewood have led to soil erosion and degradation of the remaining historic forest, resulting in a loss of natural vegetation cover [41]. Moreover, crown defoliation by processionary caterpillars (Thaumetopoea bonjeani and T. pityocampa), cedar bark stripping by Barbary Macaques (Macaca sylvanus), and damage by cedar bark beetles (Phaenops marmottani) seem to have exacerbated the recent Atlas cedar decline [37,38,42].…”

Macaques at the margins: the biogeography and extinction of Macaca sylvanus in Europe

“…Not all modern 'feeding' behaviours may have been present in past populations, however. For example, the bark stripping and consumption of cambium and sap observed in modern Barbary macaques is much more likely to be a response to exclusion from water sources because of human encroachment than because bark is an important fallback food (Camperio Ciani et al, 2001). …”

Efectos de las tendencias climáticas y la degradación del hábitat sobre el decaimiento de los cedrales (Cedrus atlantica) del norte de Marruecos

“…9). A su vez, el cambio climático parece ejercer también un efecto significativo sobre los patrones de comportamiento de estos animales (Mehlman, 1989;Hammouzaki 1996;Camperio Ciani et al 2001; Camperio Ciani y Mouna 2007).…”