Granivory in fragments from psamofilo forest in Uruguay

Abstract

The psamofilo forest on the Uruguayan coast has been fragmented due to diverse human activities. The surrounding matrices of fragments present several uses, like forestation with exotic species and cattle raising. Granivory could affect the maintenance of these fragments when modifying the recruitment of plants. We studied granivory in a site that offered conditions to make a natural experiment as it represented a fragmented forest, with patches of different sizes and separated by different matrices, in the South East of the department of Canelones. We evaluated the granivory of native (Celtis tala) and exotic seeds (Pinus pinaster) in exclusions of birds and rodents and sites of control in four fragments of different size and in the matrices (grassland, plantation of Pinus pinaster and plantation of Fraxinus pennsylvanica). No differences between the consumed species or between the fragments were observed. Nevertheless, in the matrices differences in the consumption of seeds were registered. The high consumption of the seeds in the fragments and in two of the matrices suggests a low probability of recruitment and expansion of the fragments of the forest.