A multi-scale assessment of habitat disturbance on forest animal abundance in South American temperate rainforests

Anthropogenic disturbance has dramatically degraded and reduced the extension of the temperate rainforests of southern South America, negatively affecting forest animals that depend on habitat attributes at local and landscape scales. We conducted a multi-scale assessment (from 1 to 4000 m) to understand better how local and landscape attributes influence forest animal abundance in an anthropogenic disturbance gradient. We selected five forest-dependent animal species to assess the effects of habitat alteration: an arboreal marsupial (Dromiciops gliroides) and four forest birds (Pteroptochos tarnii, Scytalopus magellanicus, Scelorchilus rubecula, and Sylviorthorhynchus desmursii). We recorded forest animal abundances in four different habitat types (old-growth native, secondary, and logged native forests and forestry plantations). We measured local attributes in the field and characterized landscape attributes remotely. We evaluated marsupial abundance using camera traps and forest bird abundance using point counts, which were analyzed with Generalized Linear Mixed Models. Locally, canopy cover positively predicted marsupial abundance, while the number of fallen logs positively predicted bird abundance. At the landscape scale, native forest cover positively affected marsupial abundance, with significant effects at all levels. Conversely, plantation cover negatively affected forest bird abundance, while landscape heterogeneity negatively affected both groups. Our results showed that the abundance of the forest animals assessed here depends on multi-scale determinants. At the local scale, we advise greater canopy cover and maintaining woody debris. On the landscape scale, maintaining native forest cover should prioritize biodiversity management in the southern South America temperate forests. It is also crucial to control the expansion of forest plantations and reduce forest fragmentation to guarantee the persistence of forest-dependent species.