Effects of Fragmentation of Polylepis Forest on Violet-throated Metaltail Hummingbirds (Metallura baroni) and other Andean Bird Species in Ecuador

What species: Many resident species, including Violet-throated Metaltail (Metallura baroni), Blue-mantled Thornbill (Chalcostigma stanleyi), Ecuadorian Hillstar (Oreotrochilus chimborazo), Giant Conebill (Oreomanes fraseri), Tit-like Dacnis (Xenodacnis parina), Mouse-colored Thistletail (Schizoeaca griseomurina), Tawny Antpitta (Grallaria quitensis), Black-billed Shrike-Tyrant (Agriornis montana), Red-rumped Bush-Tyrant (Cnemarchus erythropygius), Stout-billed Cinclodes (Cinclodes excelsior), Brown-backed Chat-Tyrant (Ochthoeca fumicolor), White-throated Tyrannulet (Mecocerculus leocophrys), Plumbeous Sierra-Finch (Phrygilus unicolor), and Many-stripe Canastero (Asthenes flammulata).

Where: Cajas National Park, Ecuador and surrounding area.

Who: Dr. Steven Latta (National Aviary), Dr. Catherine Graham (Stony Brook University, New York), Dr. Gustavo Chacón (University of Azuay, Cuenca, Ecuador), and Boris Tinoco (University of Azuay, Cuenca, Ecuador).

When: 2005 – present

Why: The Andes Mountains, which harbor the greatest concentration of restricted-range species in South America, has one of the highest concentrations of the world’s threatened bird species. The most prominent ecosystem of the Andes, the páramo, is made up of alpine bunchgrass interspersed with sedges, herbs, and low-lying mats of lichens and moss. Intermixed in the páramo are patches of Polylepis forest occurring in sheltered areas at elevations up to 4,500 m. The tropical Andes has already suffered extensive loss of habitat, and Polylepis forests in particular now show a highly disjunct distribution resulting from burning to promote livestock grazing, introduction of exotic tree species, tree cutting, cultivation, and road building. Because of this habitat fragmentation, many specialized birds endemic to Polylepis woodlands and cloud forests are now threatened with extinction and show relictual distributions. In order to document and understand how habitat alteration influences biodiversity, both monitoring (pattern) and detailed behavioral studies (process) are needed.

Current Goals: Intensive studies of a specific habitat type, Polylepis forest, to evaluate how patch area, shape, and landscape context or connectivity influences community composition, abundance, and movement patterns of bird species dependent upon Polylepis forests, with special emphasis on the endangered hummingbird, Metallura baroni.

Next Steps: We have completed studies of the distribution and habitat use by the narrow endemic, Metallura baroni, and are now undertaking community-wide studies of birds in Polylepis patches.

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