Forest ecosystem responses to edge effects and secondary forest development in northeastern Costa Rica: implications for conservation

Abstract

Forest structure was examined at 20+ year old forest-pasture edges to assess edge effects. Stem density was significantly higher at forest edges than interiors due to an increase in small diameter trees close to edges. These data show that forest edges seal with dense vegetation in the 20+ years following edge creation, suggesting that edges are robust and likely to promote high-value environmental services in these forests.Measures of water-use efficiency (WUE) and stable carbon isotopes were used to evaluate changes in forest function at edges. Forest recruitment and carbon dynamics were examined in a chronosequence of secondary forest.To evaluate Costa Rica's 1996 Forestry Law initiating environmental service payments (pago por servicios ambientales, PSA) and prohibiting deforestation, landcover data were used to compare forest change before and after 1996. As result, secondary forests will persist as minor landscape components without incentives.