Bird diversity along elevational gradients in the dry tropical Andes of northern Chile: the potential role of indigenous traditional agriculture
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2018
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Abstract
Understanding diversity patterns along environmental gradients lies at the heart of community ecology. Previous studies have found variation in bird diversity and density along “natural” elevational gradients in the Tropical Andes Hotspot. However, there is still a lack of knowledge about how bird communities respond to traditional land-use patterns, in association with other multiple drivers, across elevations. In the present study, we investigated biotic, abiotic and anthropogenic sources of variation associated with bird species diversity, density and turnover along a 3000-m elevational gradient in the southern limit of the Tropical Andes Hotspot in northern Chile. Over four seasons, we conducted 472 bird point count surveys and established 118 vegetation plots distributed across the Desert, Pre-Puna, Puna and High Andean belts. We found that species diversity and density increased until 3300 masland then declined. This type of elevational pattern is characteristic of dry-based mountains, where environmental conditions are suitable at mid-elevations. Here, habitats shaped by traditional Aymara indigenous agriculture, associated with relatively high vegetation heterogeneity, hosted the highest values of bird alpha diversity and density. We found that species turnover was structured by habitat type, while elevational ranges of most species were restricted to three relatively discrete assemblages that replaced each other along the gradient. Increasing loss of traditional agriculture and intensification of land-use may present a threat to the bird community in the Tropical Andes Hotspot.
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Tesis (Magíster en Recursos Naturales)--Pontificia Universidad Católica de Chile, 2018