Scale-Dependent Spatial Match between Fruits and Fruit-eating Birds during the Breeding Season in Yungas Andean Forests

BLENDINGER PG; JIMÉNEZ J; MACCHI L; MARTÍN E; SÁNCHEZ MS; AYUP MM

BIOTROPICA

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 47

0006-3606

The multi-scale spatial match between bird and food abundances is a main driver of the structure of fruit-eating bird assemblages. We explored how the activity of fruit-eating birds was influenced by the abundance of fruits at the local and landscape scales in Andean mountain forests during the breeding season, when most birds forage close to their nest. To do it, we measured: a) the spatial scale of variation in the abundance of fruits, b) the spatial scale of variation in the activity of fruit-eating birds, and c) the spatial match between both variables. The sampling design consisted of eleven 1.2-ha sites, each subdivided in 30 cells of 20 x 20 m where we sampled fruits and fruit-eating birds. We found that fruit consumption, and in a lesser extent bird abundance, were associated to the local spatial variation in the abundance of selected fruits. Fruit-eating birds did not modify their spatial distribution in the landscape following changes in availability of these fruits. Our study shows that fruit-eating birds are able to detect very local spatial variation in fruit availability and to exploit patches with large clusters of selected fruits in their breeding home ranges. At larger spatial scales, the absence of fruit tracking may be determined by the inability of breeding birds to respond to short-term changes in the local fruit abundance, when exploiting fruit-rich patches may no longer be profitable for breeding birds if they have to stray too far from their nests.