Effect of distance from edge on exotic grass abundance in tropical dry forests bordering pastures in Ecuador

Abstract

Abstract:We compared exotic pasture grass cover near the edges of 20–25-y-old secondary forests (N = 8) with those of mature forests (N = 8), bordering actively grazed pastures on the Pacific Coast of Ecuador. We estimated grass cover in 224 1 × 3-m plots along transects that ran from the pasture edge into forest interiors (11–44 m). Using a spline regression, we divided the transects into three segments: exterior (in the pasture), edge and interior (in the forest). With a stepwise regression, we tested the effect of transect section, forest type and distance from edge on grass cover. Forest type, distance from edge, interior transect section and the combined effect of distance from edge in both the interior and exterior sections explained variation in grass cover. Grass abundance was higher and penetrated further into secondary than mature forests. Edge proximity and differences in forest canopy openness likely favours recruitment and persistence of pasture grasses.