Edge effects on litterfall mass and nutrient concentrations in forest fragments In central Amazonia

Forest edges bordering on pasture were created by cutting and burning thesurrounding Amazonian lowland rain forest in the dry season (June) of1990. Litterfall was measured for 3.5 y along transects 10, 50, 100 and250-m into the forest from the forest edge. Litterfall along the 10-mtransects increased by up to 2.5 times that on spatial controls (250-mtransects) inthe dry season in which the edge was created. In the second dry seasonafter edge creation litterfall at 10-m was lower than on controls, afterwhich it returned to control rates in the second wet season, 1.5 y afteredge creation. Litterfall 50-m into the forest was less affected; therewas a smaller rise in the dry season in which the edge was cut, and nosignificant effects after that. At100-m there was no effect of edge creation on litterfall. Phosphorusconcentrations in litterfall were elevated along 10-m transects,10-12 wk after edge creation, possibly because of reducedretranslocation prior to abscission. The changes in litterfall describedhere are inextricably linked to the biomass collapse, which occurs nearforest-fragment edges in the same area.