Coquerel's sifaka Propithecus coquereli has a large but highly fragmented distribution. Despite its Endangered (EN) IUCN conservation status, uncertainties persist regarding its actual distribution and its presence in forests that are thought to be part of its distribution range. We provide here the first extensive population surveys of Coquerel's sifaka across a large number of forest fragments neighboring 27 sites of its known and expected distribution range in northwestern Madagascar, including 12 previously visited sites. During our diurnal surveys carried out in the dry seasons from 2009 to 2011 we observed the species in 26 of the 27 visited sites. Combining our results with previously published data, we propose a refined update of the species' distribution range and identify areas to be surveyed. We also recorded the support tree species on which sifakas were observed, and note that, surprisingly, P. coquereli was frequently seen around villages and in areas dominated by introduced tree species. Although the species was present at almost all the visited sites of its highly fragmented distribution range, it remains unclear how viable the populations of a significant proportion of these sites actually are. Due to political instability and high rates of deforestation, large-scale conservation actions are urgently needed. We thus (1) discuss the outline of a possible metapopulation conservation action plan for P. coquereli and (2) identify priority sites and actions.

23Propithecus coquereli is one of the last sifaka species for which no reliable and 24 extensive density estimates are yet available. Despite its Endangered conservation status 25 [IUCN, 2012] and recognition as a flagship species of the northwestern dry forests of 26Madagascar, its population in its last main refugium, the Ankarafantsika National Park 27(ANP), is still poorly known. Using line transect distance sampling surveys we 28 estimated population density and abundance in the ANP. Furthermore we investigate 29 the effects of roads, forest edge, river proximity and group size on sighting frequencies 30 and density estimates. We provide here the first population density estimates throughout 31 the ANP. We found that density varied greatly among surveyed sites (from 5 to ~100 32 ind/km²) which could result from significant (negative) effects of roads, and forest edge,

Very little information is known of the recently described Microcebus tavaratra and Lepilemur milanoii in the Daraina region, a restricted area in far northern Madagascar. Since their forest habitat is highly fragmented and expected to undergo significant changes in the future, rapid surveys are essential to determine conservation priorities. Using both distance sampling and capture-recapture methods, we estimated population densities in two forest fragments. Our results are the first known density and population size estimates for both nocturnal species. In parallel, we compare density results from four different approaches, which are widely used to estimate lemur densities and population sizes throughout Madagascar. Four approaches (King, Kelker, Muller and Buckland) are based on transect surveys and distance sampling, and they differ from each other by the way the effective strip width is estimated. The fifth method relies on a capture-mark-recapture (CMR) approach. Overall, we found that the King method produced density estimates that were significantly higher than other methods, suggesting that it generates overestimates and hence overly optimistic estimates of population sizes in endangered species. The other three distance sampling methods provided similar estimates. These estimates were similar to those obtained with the CMR approach when enough recapture data were available. Given that Microcebus species are often trapped for genetic or behavioral studies, our results suggest that existing data can be used to provide estimates of population density for that species across Madagascar.

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The golden-crowned sifaka (Propithecus tattersalli) is an endangered lemur species found only in the Daraina region, a very restricted area in north-eastern Madagascar. Its forest habitat is highly fragmented and expected to suffer from significant changes in the near future. The species is poorly known and only one census study, carried out in 2000, has ever been published. It is thus crucial to update the conservation status of the golden-crowned sifaka before major anthropogenic environmental changes take place. Using the line-transect approach, we estimated the species density in the main forest fragments located in both the peripheral and central parts of the distribution range, including both protected and unprotected areas. In parallel, we tried to determine whether an edge effect could be detected by comparing densities at different distances from the forest edges. We found important variation of sifaka densities among forest fragments. The total species abundance is thus difficult to determine, but we estimated that it is likely to be over 18,000, two to three times higher than previously thought. However, our data also suggested that most P. tattersalli live in forests located in the central part of the distribution range and that the estimated densities in the central part were high (>80 individuals/km(2)). Two forest fragments, found to host a large part of the total population, are currently outside the managed area and their incorporation to the managed area is strongly recommended. Lastly, as expected for a folivorous and not heavily hunted species, our results are consistent with the hypothesis that this species does not experience a clear edge effect, at least during the first half of the dry season. This could be due to a high resiliency to habitat fragmentation or to the fact that fragmentation has been going on for some time.