Is shadier better? The effect of agroforestry management on small mammal diversity

Agroforestry systems play fundamental roles for wildlife conservation, but are prone to disturbances from management practices aiming at increasing local productivity. This work investigates the small mammal assemblages present in cacao agroforests, which differ in shade tree density. We tested the prediction that higher tree density increases shade level, analyzed how some environmental variables important for small mammals (vegetation complexity, tree basal area, and invertebrate biomass) vary across the shade level gradient, and how the assemblages respond to these variations. We also tested the effect of the environmental variables on the abundance of the three most common species: Rhipidomys mastacalis, Hylaeamys seuanezi, and Marmosa murina. We captured 651 individuals belonging to 18 species. A positive relationship was observed between an abundance of non‐forest specialists and tree basal area, while species diversity within this group showed positive association with vegetation complexity. Assemblage structure (described by a matrix of species abundance per site) was not affected by our environmental variables, but R. mastacalis was more abundant in sites with lower vegetation complexity. Higher shade levels in cacao agroforest tended to occur in sites with greater tree basal area, which was not a good predictor of small mammal diversity. This suggests that environmental management to reduce shade with the purpose of increasing cacao productivity is not necessarily negative for small mammal conservation. Species diversity was favored by structurally complex systems, a possible response to greater niche diversity. in Portuguese is available with online material. Resumo em português Sistemas agroflorestais tem papel fundamental na conservação da vida silvestre, mas são propensos a distúrbios resultantes de práticas de manejo que visam o aumento da produtividade local. Este trabalho investiga as assembleias de pequenos mamíferos em agroflorestas de cacau que diferem em relação à densidade arbórea. Testamos a predição de que uma maior densidade arbórea aumenta o nível de sombreamento, analisamos como algumas variáveis ambientais importantes para os pequenos mamíferos (complexidade da vegetação, área basal de árvores e biomassa de invertebrados) variam ao longo do gradiente de sombreamento, e como as assembleias respondem a essas variações. Testamos também o efeito das variáveis ambientais na abundância das três espécies mais comuns: Rhipidomys mastaca