Litter Production and Accumulation as an Indicator of Degradation in Caatinga

Abstract

The ecosystem processes in the caatinga, such as litter dynamic, are threatened and little is known about it in these environments. The litter processes can be used as indicators of degradation or recovery of an ecosystem because these processes react to changes in the ecosystems. The litterfall deposition was collected monthly over 23 months in collectors of 1.0 m2. The litter accumulation on soil was collected monthly over 23 months in frames of 0.25 m2. The coefficient of decomposition (K) was estimated by the relation between annual litter production and litter stock in the soil surface. Annual litterfall production increased with stand age. Total annual litter production in different age stands varies from 1.37 Mg ha-1 in the 15 years to 2.37 Mg ha-1 in the 50 years stand. K and renewal times were also significantly different among the sites. K was higher in 50 years, followed by 30 years and 15 years. There were a higher litter production and accumulation in the older stands. The older stands presented faster litter decomposition and renew, which evidences a better utilization of litter in the nutrient cycling process and the incorporation of organic matter into the soil. These results show that litter processes are effective indicators of the stage of degradation in a caatinga ecosystem.