Fragmentation and edge effects on plant-animal interactions, ecological processes and biodiversity.

Abstract

We summarize studies of forest fragmentation and edge effects on a diverse range of ecological processes and abiotic variables in neotropical montane and south temperate rainforests in Chile and Mexico. The main findings from these studies are that: (i) anthropogenic edge effects significantly altered forest regeneration processes occurring over small spatial and temporal scales; (ii) the adjacent vegetation type affected not only the probabilities of tree invasion and regeneration, but also the extent of microclimatic edge effects within the forest interior; and (iii) the edge structure and function are linked as a habitat for plants and animals and as a front for forest expansion. We found that the main modulators of edge effects were: (i) forest edge to non-forest matrix contrast (hard and soft edges); (ii) edge orientation with respect to biotic or abiotic fluxes; (iii) season (dry or wet) or year of study (temporal variance); and (iv) species-specific responses. Future edge studies should consider the modulators of edge effects for the particular response variable being studied. The consequences of edge effects for the conservation of regional biodiversity and changes in forest structure in fragmented forest landscapes are discussed.