Herbivory damage on oak seedlings at the edge of cloud forest fragments

Abstract

Herbivory damage on Quercus xalapensis Humb. et Bonpl. seedlings was experimentally determined in two cloud forest fragments (Veracruz, Mexico), one with an abrupt edge (forest contiguous to a one-year old stand), and another with a soft edge (forest contiguous to a 10 year-old stand). Sets of seedlings were planted in transects parallel to the border. The experiments were conducted in the warm-dry (April-May) and warm-wet (July-August) seasons. Herbivory damage was measured at the beginning and at the end of each season. Weekly, microclimatic variables were measured in the same positions in which seedlings were planted. During the wet season, herbivory was similar at different distances from the border (ca. 2%), but during the dry season, herbivory was higher at the forest border (2.75-11.75%) than at the old-field (0.50-0.75%). Herbivory and air temperature were higher, and air humidity and soil water content were lower in the abrupt than in the soft edge. Our results suggest that herbivory levels on oak seedlings depend on modulating factors such as the edge type and the season of the year.