Factors Limiting Tropical Rain Forest Regeneration in Abandoned Pasture: Seed Rain, Seed Germination, Microclimate, and Soil1

摘要: Vegetation, seed rain, germination, microclimate, and soil physical chemical parameters were measured in a recently abandoned pasture adjacent primary rain forest southern Costa Rica. The goal of this study was to assess the importance these factors limiting regeneration pastures. Seed animal dispersed species decreased dramatically >5 m from forestlpasture edge; fewer wind seeds fell than forest, but difference much less for seeds. Percent germination most studied similar with grasses; lower during dry season areas cleared grasses. Air temperature, vapor pressure deficit (VPD), photon flux density (PFD) higher at 1 above ground. VPD PFD ground level temperature indicating that grasses strongly modify microclimatic conditions near surface. lowest gravimetric water content recorded 0.5 leaf relative contents two identical, suggesting plants not stressed. Levels nutrients as compared forest; however, aboveground root biomass seedlings grown soils did differ significantly. Although number impede recovery pastures, results suggest important limitation is lack dispersal.