The Use of Vanilla Plantations by Lemurs: Encouraging Findings for both Lemur Conservation and Sustainable Agroforestry in the Sava Region, Northeast Madagascar

摘要

Extensive areas of forest are cleared every year to establish new agricultural land in the tropics, resulting in a catastrophic loss in habitat for the world's primates. A prominent example of this process is Madagascar, where an increasing demand for arable land has led to the once-forested landscape to be now dominated by agricultural areas used for the cultivation of food and cash crops. Despite the prominence of these plantations throughout Madagascar, their suitability as a habitat to support endemic lemur populations remains unclear. Here, we assessed lemur presence in vanilla plantations, Madagascar's principal export crop, within the northeastern Sava region with the use of line transects. We confirmed the presence of five lemur species, four of which were nocturnal cheirogaleids, in these vanilla plantations. Intensively farmed vanilla plantations and those in existing stands of vegetation supported at least one species of lemur. Furthermore, lemurs were significantly more likely to be present in plantations grown close or adjacent to natural forest fragments, compared to more intensively farmed, anthropogenic sites. In comparison, we observed eight lemur species in natural forest fragment sites in close proximity to the vanilla plantation sites, four of which we did not observe in any of the plantation sites. Our results provide evidence of lemurs using vanilla plantations and show that vanilla plantations may act as extensions of suitable habitat for lemurs, suggesting that they may also function as matrices between isolated forest fragments through which gene flow can occur. These are important and encouraging findings for both lemur conservation and for sustainable agroforestry undertaken by local farming communities.