Effects of landscape fragmentation on bird communities in a tropical hotspot
Changes in land-use such as agricultural expansion and urbanization lead to landscape fragmentation among the Tropical Andes. This region also has exceptionally high levels of biodiversity and endemism; hence, it has become a priority for conservation efforts. Ecuador is part of Tropical Andes and i...
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|Summary:||Changes in land-use such as agricultural expansion and urbanization lead to landscape fragmentation among the Tropical Andes. This region also has exceptionally high levels of biodiversity and endemism; hence, it has become a priority for conservation efforts. Ecuador is part of Tropical Andes and in the Ecuadorian high-altitude Andes habitat loss is already widespread and persistent.
A representative area for Andean avifauna is Cajas National Park. The park is located in the southern Andes of Ecuador and is the only protected area in the south-western Andes. The park is characterized by containing 90% páramo grassland ecosystem which surrounds > 1000 patches of Polylepis woodland. Despite its importance for bird conservation and its protected status, the Cajas National Park suffers from several stressors, which are modifying the natural habitat characteristics of both páramo grassland and Polylepis patches. We tested the effect of roads (as a major stressor), habitat structure and vegetation composition of both the páramo matrix and the Polylepis patches on the bird community.
We found the habitat-specialized birds such as shrubby páramo birds had reduced abundance at the roadsides due to habitat modification led by the introduction of non-native plants. This same condition drives further change in community composition with generalist and a few páramo specialists being found within the area influenced by the road. Our findings also confirm the importance of natural heterogeneity of páramo grassland and the quality of small and medium-sized patches of Polylepis forest. For instance, there is a positive relationship of Polylepis specialist movement (between patch and matrix) with an increase in the proportion of woody plants. Furthermore, Polylepis patches located in higher altitude increased the centrality index of Polylepis specialists.
The loss of specialized birds in disturbed areas and also the positive effect of Polylepis quality and páramo heterogeneity are crucial to a better understanding of the dynamics in the high-altitude Andes. Here, there is a vital importance to take on a landscape view, where not only large Polylepis patches are considered vital for avian conservation. Furthermore, human activities in the páramo landscape may reduce the natural habitat heterogeneity with a negative influence on biodiversity patterns.
Several protected areas in Ecuador include large areas of páramo ecosystem and all of them are highly threatened; to promote effective nature conservation it is imperative to develop conservation plans that take habitat heterogeneity into account both in Ecuador and throughout the Andean region.|