Edge effects in tropical forest fragments: Application of a model for the design of nature reserves
There have been few quantitative studies of edge effects in tropical rainforest fragments. I used physiognomic, edaphic, and floristic data from 52 900-m2 plots to describe edge effects in such fragments in NE Queensland, Australia. Relative to unfragmented forest, forest fragments ranging from 1[middle dot]4 to 590 ha in area had higher canopy and subcanopy damage and exceptional abundance of heavy lianas, climbing rattans Calamus spp., and other disturbance-adapted plants (Dendrocnide spp., Solanum spp.). Elevated forest disturbance was evident up to 500 m inside fragment margins, although the most striking changes occurred within 200 m of edges. Application of these data with a mathematical ‘Core-Area Model’ suggested that isolated nature reserves in NE Queensland must exceed 2000-4000 ha, depending on reserve shape, to ensure that >50% of the reserve remains unaffected by induced forest.