The distribution of most recently discovered or described lemur species remains poorly known, but many appear to have small geographical ranges, making them vulnerable to extinction. Research can contribute to future conservation actions on behalf of these species by providing accurate information on local distribution and abundance. The distribution of the world’s smallest primate, the endangered Madame Berthe’s mouse lemur (Microcebus berthae), is limited to the Menabe Central region of western Madagascar. This species was discovered in the 1990s, but many fundamental aspects of its ecology remain unknown. The aims of our study were therefore to determine the actual distribution of Microcebus berthae across the forests of this region, to estimate population density, and to examine the species’ response to anthropogenic activities. We established 35 1-km line transects across Menabe Central, on which we surveyed mouse lemurs by distance sampling and live trapping. Microcebus berthae does not occur in all remaining forests of this small region and its population density is highly heterogeneous, both across its geographic range and locally. Within its area of occupancy, the population of Microcebus berthae not only was distributed according to spatial heterogeneities of the habitat, but also responded to anthropogenic disturbances and varied seasonally. Our results indicate that Microcebus berthae is susceptible to habitat degradation and avoids human environments spatially. As none of the forest remnants in which the species still occurs were officially protected until recently, immediate conservation actions should focus on effectively protecting Kirindy and Ambadira forests.

中文翻译：

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世界上最小的灵长类动物 Microcebus berthae 在马达加斯加中西部的分布和数量

最近发现或描述的狐猴物种的分布仍然知之甚少，但许多物种的地理范围似乎很小，使它们容易灭绝。通过提供有关当地分布和丰度的准确信息，研究可以为代表这些物种的未来保护行动做出贡献。世界上最小的灵长类动物——濒临灭绝的贝尔特夫人鼠狐猴（Microcebus berthae）的分布仅限于马达加斯加西部的梅纳贝中部地区。该物种于 1990 年代被发现，但其生态学的许多基本方面仍然未知。因此，我们研究的目的是确定该地区森林中 Microcebus berthae 的实际分布，估计种群密度，并检查该物种对人为活动的反应。我们在 Menabe Central 上建立了 35 条 1 公里的横断面，在这些横断面上我们通过距离采样和现场诱捕来调查鼠狐猴。Microcebus berthae 并未出现在这个小区域的所有剩余森林中，其种群密度在其地理范围和局部范围内都具有高度异质性。在其居住区域内，Microcebus berthae 的种群不仅根据栖息地的空间异质性分布，而且还对人为干扰做出反应并随季节变化。我们的结果表明 Microcebus berthae 容易受到栖息地退化的影响，并且在空间上避开人类环境。由于直到最近，仍然存在该物种的森林遗迹都没有受到正式保护，