The recognition that much biodiversity exists outside protected areas is driving research to understand how animals survive in anthropogenic landscapes. In Madagascar, cacao (Theobroma cacao) is grown under a mix of native and exotic shade trees, and this study sought to understand whether lemurs were present in these agroecosystems. Between November 2016 and March 2017, discussions with farmers, nocturnal reconnaissance surveys and camera traps were used to confirm the presence of lemurs in the Cokafa and Mangabe plantations near Ambanja, north-west Madagascar. Four species of lemur were encountered in nocturnal surveys: Mirza zaza, Phaner parienti, Microcebussp. and Cheirogaleussp. with encounter rates of 1.2, 0.4, 0.4 and 0.3 individuals/km, respectively. The presence of Lepilemur dorsalis was confirmed by camera trap. This is the first time lemurs have been studied in cacao plantations, and understanding how these threatened animals use anthropogenic landscapes is vital for their conservation.
The Critically Endangered blue-eyed black lemurEulemur flavifronsof north-western Madagascar is one of the most threatened primates. The majority of research and conservation efforts for the species have been restricted to the Sahamalaza Peninsula but there are unstudied and unprotected populations farther inland. The dearth of information regarding the transition betweenE. flavifronsand its parapatric sister species, the Vulnerable black lemurEulemur macaco, and the possibility of a hybrid population complicates conservation planning for both species. We surveyed 29 forest fragments across both species’ ranges to investigate the boundary between the taxa, whether hybrids persist, and the threats to lemurs in the region. We foundE. flavifronsin six fragments andE. macacoin 17. We never observedE. flavifronsandE. macacoin the same location and we found no conclusive evidence of hybrids. Three fragments in whichE. flavifronswas present were north of the Andranomalaza River, which had previously been considered the barrier between the two species. Based on these observations and a literature review, we provide updated ranges, increasing the extent of occurrence (EOO) ofE. flavifronsby 28.7% and reducing the EOO ofE. macacoby 44.5%. We also evaluate the capacity of protected areas to conserve these lemurs. We recommend additional surveys and the implementation of an education programme in this region to help conserve both species.
Primate encounter rates often vary throughout the year due to seasonal differences in activity, ecology, and behaviour. One notably extreme behaviour is continuous hibernation. Although a rare adaptation in primates, the dwarf lemurs of Madagascar (genus Cheirogaleus) enter obligate hibernation each year during the dry season, after spending the wet season consuming high-energy foods. Whilst seasonal changes in activity in some Cheirogaleus populations are well-known, many species remain little-studied, and there is no specific information on their encounter rates, nor when they enter and emerge from hibernation. This uncertainty critically affects reliable calculation of population density estimates for these highly threatened lemurs. In this study, we assessed how encounter rates of the fat-tailed dwarf lemur (C. medius) vary seasonally in the transitional forests of the Sahamalaza-Iles Radama National Park, northwest Madagascar, during a 4-year period. We established a system of line transects (N = 60) throughout our study area, on which we conducted distance sampling of C. medius. We then used our distance sampling data to calculate encounter rate and population density data. We found encounter rates of C. medius to be significantly higher during the wet season compared with the dry season. Furthermore, encounter rates of C. medius were particularly low from May–August. These results provide some evidence to suggest the time period that C. medius hibernate in Sahamalaza-Iles Radama National Park. These findings underpin the importance of careful study design when surveying threatened species with seasonal differences in activity, such as those that hibernate. This study also demonstrates the importance of species-specific behavioural data for accurate population density assessment, which is required to inform conservation action.
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