Aves migratorias en agroecosistemas del norte de Latinoamérica, con énfasis en Colombia

The significant role that agricultural lands play in the conservation of global biodiversity is increasingly being recognized. Migratory birds, with their wide distributions, high mobility and ability to track variable resources, are common in many agricultural habitats. Although presence alone does not guarantee that agroecosystems provide the same benefits to birds as natural habitats, some agroecosystems are considered to have become important for the maintenance of migratory bird populations. In this study we carried out an extensive literature review to examine the presence of migrants in the principal productive habitats of Colombia and Latin America, and we undertook surveys in little studied agricultural habitats in Colombia. We found that 87% of the migratory species reported in Colombia occur in agroecosystems either in the country or in Latin America. Shade-grown coffee, cacao and silvopasture supported the highest species richness and abundance of migrants. According to the literature, the value of these agroforestry systems increases with increasing shade cover, tree diversity and complexity of vegetation structure. Landscape scale effects are also important, like the presence of surrounding natural habitats and of elements that promote connectivity. Field observations revealed that irrigated rice fields contained important numbers of migratory waterbirds (29% of the species considered in this study). Conversely, the richness and abundance of migratory birds in maize and teak plantations were much lower, presumably due to the reduction in vegetation complexity and structure found in these monocultures.