Efeito do estresse hídrico na produção de serapilheira, em floresta de terra firme, Caxiuanã-Pa

Abstract

The importance of quantifying the production of burlap associated with the parameters that affect its variation is widely recognized for understanding ecosystem dynamics, as it is a fundamental process in the cycling of nutrients and is an important way of transferring organic matter and mineral elements from the vegetation to the soil surface in forest ecosystems. Several researchers argue that the total amount of burlap produced and its components can be affected when they are under water stress, which consequently can also affect other mechanisms such as water cycling. In view of the above, this study aims to evaluate the influence of rainwater exclusion on the variation of burlap production and to identify the main meteorological variables that influence the variation of burlap production. The study area was the Scientific Station Ferreira Penna, municipality of Melgaço, Pará, within the LBA Program Project. We installed 40 apparatuses for the collection of litter on two plots of one hectare each (plots A and B), in the area of the ESECAFLOR Experiment. The first plot, where we tried to exclude about 80% of rainfall, the control plot remained in natural environmental conditions. In the period February/200! to December/2006, monthly samples of litter were collected for quantification of monthly production and moisture determination. Precipitation and seasonal age information were used in the analysis of the relationship between the quantity data of burlap production, as well as its components, and the existence of an influential relationship between seasonality and burlap production in the ecosystem was verified. There is also a significant influence of precipitation on the production and decomposition of burlap, which increases its production in the period of less rainy season, and has its decomposition accelerated with the presence of rain. The periods of highest and lowest production of burlap were from July/2006 to December/2006, respectively. The temperature was a variable that influenced the production of burlap due to its production being higher at higher temperatures, with a monthly average around 26 to 30°C in the region of Caxiuanã.