Patch size is considered a major driver of species diversity in fragmented landscapes. Yet, assemblages of forest-dependent species, such as tropical arboreal mammals, can also depend on vegetation characteristics within the patch, i.e. patch quality. To test this, we assessed the influence of patch size and quality (measured through six attributes of vegetation structure) on arboreal mammals in 20 forest patches in the Lacandona rainforest – a biodiversity hotspot in the Mesoamerican Biological Corridor. We placed camera traps in 100 trees and registered arboreal mammals for one year. We used generalized linear models with a multimodel averaging approach and a distance-based redundancy analysis to identify the relative importance of patch size and quality on arboreal mammal diversity and composition. Species diversity was mainly and positively influenced by tree basal area – a vegetation attribute indicative of older and better-preserved forests – while species composition was driven by both patch size and quality. Patch size was negatively related to the abundance of kinkajous and Deppei’s squirrels, likely due to a higher density (and detectability) of individuals in small patches. The abundance of kinkajous and Deppei’s squirrels was lower in patches with higher tree density – an attribute typically related to forest disturbance. Therefore, to effectively preserve this highly endangered and ecologically relevant group of mammals, both patch size and quality should be considered, paying special attention to the conservation of large trees.

斑块大小被认为是支离破碎景观中物种多样性的主要驱动力。然而，依赖森林的物种（例如热带树木哺乳动物）的聚集也可能取决于斑块内的植被特征，即斑块质量。为了测试这一点，我们评估了斑块大小和质量（通过植被结构的六个属性来衡量）对Lacandona雨林（中美洲生物走廊中的生物多样性热点）的20个森林斑块中的树栖哺乳动物的影响。我们在100棵树上放置了相机陷阱，并注册了树栖哺乳动物一年。我们使用具有多模型平均方法和基于距离的冗余分析的广义线性模型来确定斑块大小和质量对树栖哺乳动物多样性和组成的相对重要性。物种多样性主要受树基面积的积极影响，而树基面积是植被的属性，指示着较老和保存得更好的森林，而树种的组成则受斑块大小和质量的影响。斑块的大小与近亲和德皮松鼠的数量呈负相关，这可能是由于小斑块中个体的密度（和可检测性）更高。在树木密度较高的斑块中，近亲和德皮松鼠的数量较低，这通常与森林干扰有关。因此，为了有效地保护这一高度濒危和生态相关的哺乳动物群，应同时考虑斑块的大小和质量，并特别注意保护大树。