Avian community structure and habitat use of Polylepis forests along an elevation gradient

As one of the highest forest ecosystems in the world, Polylepis forests are recognized both as center of endemism and diversity along the Andes and as an ecosystem under serious threat from habitat loss, fragmentation, and climate change due to human activities. Effective conservation efforts are limited, in part, by our poor understanding of the ecology and habitat needs of the ecosystem's flora and fauna.

In 2014-2015, we studied bird communities and 19 associated local and landscape attributes within five forested glacial valleys within the Cordillera Blanca and Huascaran National Park, Peru. We surveyed birds during the dry (May-August) and wet (January-April) seasons at 130 points distributed along an elevational gradient (3,300-4,700 m) and analyzed our data using Canonical Correspondence Analysis (CCA).

We associated a total of 50 species of birds, including 13 species of high conservation concern, with four basic habitat types: (1) Polylepis sericea forests at low elevations, (2) P. weberbaueri forests at high elevations, (3) Puna grassland and (4) shrublands. Four species of conservation priority (e.g., Microspingus alticola) were strongly associated with large forest patches (∼10-ha) of P. sericea at lower elevations (<3,800 m), whereas another four (e.g., Anairetes alpinus) were associated with less disturbed forests of P. weberbaueri at higher elevations (>4,200 m).

Results suggest two key strategies form the cornerstones of conservation efforts: (a) protect large remnant (>10-ha) P. sericea forests at lower elevations and (b) maintain all relicts of P. weberbaueri, irrespective of size, at high elevations (>4,200 m).