The impact of urbanization and agricultural development on vultures in El Salvador

Abstract

Turkey and Black vulture ranges are expanding in the Americas despite environmental change, while Old World vulture populations are declining in Eurasia and Africa. The distribution of vultures is under-researched in El Salvador, arguably the most environmentally degraded Latin American nation. This article tests the hypothesis that Turkey and Black vulture adaptation to extremely modified landcover, recorded elsewhere, ensures their survival in El Salvador. The methodology uses point count surveys of vulture species density along an urban to forest gradient (dense downtown areas, suburbs, rural villages and farms, mixed uninhabited savanna, open and closed forests). The very common Black Vulture and the slightly less common Turkey Vulture were most often recorded in downtown areas, followed successively by suburban, fallow, savanna and forests. Only downtown and suburban areas, and to a much lesser extent farm fallow, recorded significantly more vultures than the other landcover categories, despite reduced vulture numbers along the gradient towards the forest. The much rarer Lesser Yellow-headed Vulture was most often recorded in farm/grass mosaics and the rarer King Vulture was recorded in forest. Turkey and Black vultures have adapted strongly to extreme environmental change in El Salvador. This result is important as an indicator study for assessing the ecology of these vulture species in less degraded areas.

Keywords: vulture, urbanization, environmental change, El Salvador, conservation