Effects of the structure of pine plantations on their "softness" as barriers for ground-dwelling forest birds in south-central Chile

Abstract

Fragmentation combined with habitat loss can affect population persistence mainly by isolating habitat fragments. However, this isolation depends, in part, on the species’ perception of the surrounding matrix compared to remnant characteristics. Coastal forests of the Maule region have been severely fragmented. Surprisingly, forest remnants embedded in a pine plantation matrix hold most of the avian species expected for this kind of forest. This pattern has been explained by the fact that the structure of pine plantations may not be too different from that of native forests, allowing plantations to act as a ‘‘soft barrier’’ to dispersal among fragments.With playback experiments, we evaluated the effect of the structure of Monterey pine plantations, expressed as stand age, and understory cover, on the willingness of three ground-dwelling forest species (Rhinocryptidae: Pteropotochos castaneus, Scytalopus fuscus, and Eugralla paradoxa) to move from native remnants into pine plantation matrix during the breeding season 2004–2005 in the coastal range of south-central Chile. The distance of intrusion into the matrix of all species was positively related to understory cover. Only the movement of P. castaneus was significantly related to stand age. These attributes and their spatial array may affect functional connectivity and therefore species dispersal and population persistence in this fragmented landscape.