LITTER DEGRADATION IN PLACES WITH PRIMARY AND SECONDARY VEGETATION OF THE TAMAULIPAN TRHONRSCRUB

Abstract

Litter decomposition is a critical process for the maintenance of the fertility and productivity of terrestrial ecosystems. Most studies about litter decomposition were made in temperate forests ecosystems. For this reason a study was made with the aim to determine the decomposition rate of litter from sites of primary and secondary vegetation in the Tamaulipean Thornscrub in Nuevo Leon, Mexico, in which the litter bags method was used. Sixty nylon bags were filled with fresh fallen litter from this type of vegetation and were located in four study sites, two with primary vegetation and two with secondary vegetation. Every month five bags were collected from the sites, which were dried and then weighted. The experiment lasted 300 days. For each site annual weight loss, percentage of daily degradation and litter decomposition rate (k) were estimated. Comparisons between sites by mean variance analysis (ANOVA) were made. The maximal percentage of decomposition for the study sites were: 25.92% for site one; 24.58% for site two; 26.16% for site three, and 26.51% for site four. The mean weight after 300 days were: 14.8 g (NS) for site one; 16.1 g (NS) for site two; 14.7 (NS) for site three, and 14.6 (NS) for site four. The litter decomposition rates (k) were: -0.42 (NS) for site one; -0.43 (NS) for site two; -0.47 (NS) for site three, and -0.50 (NS) for site four. No significant differences between the study sites of primary vegetation and the study sites of secondary vegetation were found, even though the sites with primary vegetation showed a slightly higher litter decomposition rate. The k values estimated in this study were similar to those registered for similar vegetation types.