Structural complexity is a better predictor than single habitat attributes of understory bird densities in Andean temperate forests.

The article investigates how forest structural complexity compares to individual habitat attributes in predicting the density of four understory specialist bird species in the Andean temperate forests of southern Chile, a recognized Global Biodiversity Hotspot. Using data from 505 plots surveyed between 2011 and 2013, the authors developed an index of stand structural complexity (ISC) based on five key habitat attributes: understory density, coarse woody debris volume, number of snags (standing dead trees), tree diameter at breast height, and leaf litter depth. Results showed that the densities of three Rhinocryptidae species (Pteroptochos tarnii, Scelorchilus rubecula, and Scytalopus magellanicus) were positively correlated with the ISC, indicating that combined habitat complexity better predicts their abundance than single attributes. In contrast, the Furnariidae species Sylviorthorhynchus desmursii was positively associated with understory density and litter depth but negatively with snag density. The study highlights the importance of retaining multiple structural habitat components to conserve understory specialist birds and recommends incorporating structural complexity indices into forest management and conservation planning in temperate South American forests.