Habitat loss and fragmentation affect species occurrence and distribution in rapidly changing ecosystems. These issues are especially relevant on the Island of Madagascar where modern deforestation has been widespread and is ongoing. We investigated the occurrence of the critically endangered Coquerel's sifaka (Propithecus coquereli) in an anthropogenically modified landscape: the Mariarano region of north-western Madagascar. We surveyed four large forest sites from 500 to 5,000 ha and 16 forest fragments ranging from 1.5 to 19.2 ha in size. We recorded various attributes of the visited sites such as area, distance to nearest large forest and anthropogenic disturbance. We encountered sifakas in 10 of 16 fragments and in all large forest sites, with the majority of encounters occurring in habitat edge zones. Furthermore, we encountered 19 sifakas in the matrix such as in villages and fields. We found that neither human disturbance, area nor distance to a large forest predicts the presence of sifakas in the Mariarano region. Our results suggest that Coquerel's sifakas are able to persist in highly degraded and small forests fragments, but further research is needed on their long-term viability in anthropogenically modified landscapes.

中文翻译：

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马达加斯加西北部分散的景观中极度濒临灭绝的Coquerel's sifaka（Propithecus coquereli）的分布

生境的丧失和破碎影响着迅速变化的生态系统中物种的发生和分布。这些问题在马达加斯加岛上尤其重要，在马达加斯加岛上，现代森林砍伐现象十分普遍，而且仍在持续。我们调查了极度濒危的Coquerel's sifaka（Propithecus coquereli）的发生）在人为改变的景观中：马达加斯加西北部的Mariarano地区。我们调查了500到5,000公顷的四个大型森林地带，以及从1.5到19.2公顷不等的16个森林碎片。我们记录了所访问站点的各种属性，例如面积，到最近的大森林的距离和人为干扰。我们在16个碎片中的10个中以及所有大型森林中都遇到了sifakas，大部分相遇发生在栖息地边缘区域。此外，我们在矩阵中（例如在乡村和田野中）遇到了19个sifakas。我们发现，没有人为干扰，面积或与大森林的距离都无法预测Mariarano地区存在sifakas。我们的结果表明，Coquerel的sifakas能够在高度退化的森林小片段中持续存在，