XVI International Botanical Congess

This study tests the hypothesis that gaps formed by selective logging delay leaf litter decomposition and affects decomposer activity in a lowland Atlantic forest of Brazil (21_24?S,41_04?W). Coarse-mesh (CM, 2 mm) and fine-mesh (FM, 40µm) litter bags filled with 3.0g of Metrodorea nigra leaves were set up in three gaps (GA) and interior (IA) areas in the wet season and lasted for 395d. Soil humidity, air and soil temperature, and total solar radiation were measured. The remaining leaf material in CM was similar between GA (51%) and IA (52%) after 395d, whereas in FM it was higher in GA (59%) than in IA (47%). Soil humidity (10-13%=wet season, 2-4%=dry season) and air temperature were not different between the areas. The soil temperature and solar radiation was higher in GA (29_C, 669µmol/sm2) than in IA (25_C, 21µmol/sm2). The slow decomposition in FM bags indicates a decrease in microbial activity, which is related to higher soil temperature and radiation in the gaps.