A avaliação da influência da exclusão da precipitação sobre a variação na produção de liteira foi realizada na . A produção total de liteira foi distribuída em folhas (61,40 %), gravetos (18,45 %) e partes reprodutivas (20,14 %). Os resultados obtidos na parcela sob condições naturais apresentaram uma maior produção de liteira, aproximadamente 25 %, comparada com a produção de liteira na parcela submetida à exclusão da água de chuva. As variáveis mais fortemente correlacionadas com a produção de liteira e suas componentes foram a velocidade do vento, a densidade de fluxo de radiação solar global, a densidade de fluxo de radiação fotossintéticamente ativa, a temperatura do solo a 5 cm de profundidade, a precipitação, o déficit hídrico e o excesso hídrico.PALAVRAS-CHAVE: Liteira, Floresta Amazônica, Decomposição, Variáveis Meteorológicas, deficiência hídrica. Influence of meteorological variables in the litterfall production in the Fer�Fer� reira Penna Scientific Station, Caxiuanã, Pará, Brazil ABSTRACTThe evaluation of the influence on the exclusion of rainfall on the variation of litter production was done in Caxiuanã Forest Reserve at Ferreira Penna Scientific Station (1º 42 ' S, 51º 31 ' W) during the period from March, 2001 to February, 2003 with the objective of identifying the main meteorological variables and the main components of the monthly water balance that affected the production and decomposition of litter. This work was part of the subproject EXPERIMENT OF DROUGHT IN THE FOREST (ESECAFLOR), that aimed to study the long term impacts of drought on the water, energy and carbon dioxide fluxes in the Amazon forest. The sazonality of total litter production and its components (leaves, brushwood and reproductive parts) was well established, with the occurrence of a greater litter production during the months with lower precipitation. The monthly litter production during the experimental period ranged from 294.78 kg.ha -1 to 1758.69 kg.ha . The total litter production was partitioned in leaves (61.40 %), brushwoods (18.45 %) and reproductive parts (20.14 %). The results obtained in the undisturbed plot showed a higher litter production, about 25 %, compared to the litter production in the plot under the exclusion of water. The variables more strongly correlated with litter production and its components were wind speed, global solar radiation density flux, photosynthetic active radiation density flux, soil temperature at 5 cm depth, precipitation, soil water deficit and water surplus.

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A review is presented of soil properties and litter fauna of an experimental site in the Caxiuanã forest, eastern Amazonia, as a contribution to the Large-Scale Biosphere–Atmosphere Experiment in Amazonia (LBA). This study’s main scientific goal is to compare some biogeochemical soil properties of an undisturbed forest ecosystem with those of an experimental (1 ha) plot in which rainfall was artificially excluded to simulate drought [the Efeitos da Seca da Floresta (ESECAFLOR) experiment]. A second scientific objective is to investigate the space variability of soil profile characteristics in the experimental sites, particularly organic carbon concentration, moisture, and texture. It is expected that such soil property variability influences greatly the distribution of several biological species such as spiders. To investigate such effects in the litter spider community, we applied percentual complementarity and Simpson diversity index to available data. Our results suggest that a faunal transition was under way in the treatment plot, shifting from a rich and even community to a less diverse one.