Laurent Tarnaud

A major increase in the population of brown lemurs on Mayotte since the decline reported in 1987

The population of the Mayotte brown lemur Eulemur fulvus fulvus on the island of Mayotte in the Indian Ocean was reported to have decreased by 50% between 1975 and 1987, from 50,000 to 25,000. From a series of censuses carried out in 1999 and 2000 in the various vegetation types of the island, we estimate that the lemur population now numbers 42,000–72,000. The decline observed in 1987 may have been largely caused by the cyclone that devastated Mayotte in 1984. That the population has recovered must not obscure the fact that loss of forest, increased human pressure associated with further development of infrastructure, and changes in agricultural practices will undoubtedly continue to affect this species on Mayotte.

Leaf chemistry as a predictor of primate biomass and the mediating role of food selection: A case study in a folivorous lemur (Propithecus verreauxi)

Folivorous primate biomass has been shown to positively correlate with the average protein‐to‐fiber ratio in mature leaves of tropical forests. However, studies have failed to explain the mismatch between dietary selection and the role of the protein‐to‐fiber ratio on primate biomass; why do not folivores always favor mature leaves or leaves with the highest protein‐to‐fiber ratio? We examined the effect of leaf chemical characteristics and plant abundance (using transect censuses; 0.37 ha, 233 trees) on food choices and nutrient/toxin consumption in a folivorous lemur (Propithecus verreauxi) in a gallery forest in southern Madagascar. To assess the nutritional quality of the habitat, we calculated an abundance‐weighted chemical index for each chemical variable. Food intake was quantified using a continuous count of mouthfuls during individual full‐day follows across three seasons. We found a significant positive correlation between food ranking in the diet and plant abundance. The protein‐to‐fiber ratio and most other chemical variables tested had no statistical effect on dietary selection. Numerous chemical characteristics of the sifakas diet were essentially by‐products of generalist feeding and “low energy input/low energy crop” strategy. The examination of feeding behavior and plant chemistry in Old World colobines and folivorous prosimians in Madagascar suggests that relative lack of feeding selectivity and high primate biomass occur when the average protein‐to‐fiber ratio of mature leaves in the habitat exceeds a threshold at 0.4. Am. J. Primatol. 76:563–575, 2014.

Berenty Reserve: Interactions Among the Diurnal Lemur Species and the Gallery Forest

The gallery forest of Berenty Reserve contains two native diurnal lemurs, the ring-tailed lemur, Lemur catta and Verreaux’s sifaka, Propithecus verreauxi, as well as introduced hybrid brown lemurs Eulemur rufifrons ´ E. collaris. Feeding data indicate that competitive mutualism, an indirect interaction, may be occurring among these three species: L. catta and P. verreauxi apparently prevent Eulemur from accessing certain foods, although brown lemurs are dominant and compete directly with the ring-tailed lemurs for tamarind fruits. Indeed, brown lemurs eat the fruits while still green and deplete the abundance of ripe fruit later available to the ring-tailed lemurs. This behavior may reduce recruitment of tamarind seedlings. In contrast, ring-tailed lemurs benefit the gallery forest by dispersing the few ripe tamarind seeds available.