Manejo da regeneração natural de vegetação de cerrado, em áreas de pastagem, como estratégia de restauração na Fazenda Santa Maria do Jauru, município de Porto Esperidião, MT

Abstract

The cerrado vegetation areas within Mato Grosso State have been largely devastaded and few efforts have been done to intercept this situation. Conservation and vegetational diversity restoration studies are essential and strenghten with the Floresteca Agroflorestal Ltda company purposes, which embodies the environmental adjustment of its production properties. For this matter, ecological restoration through natural regeneration assistance should be the most appropriate technique. This is due to the fact that there are plenty natural remnants in this region, which assure a reasonable level of resilience, based on a high regeneration potencial, mainly through root sprouting. The attempts of this study is to evaluate the natural regeneration potencial as a technique to restore cerrado vegetation areas, previously used as pasture, analysing different management methods with ecological processes and vegetational diversity restoration purposes. To evaluate natural regeneration, fifty 10x10meters plots (total of 5000m2) were randomly distributed. A previous evaluation of regeneration within these plots was made before treatments were applied. Five treatments were applied, each one represented by 10 replicates; treatments were: control (T); manual weed in a cicle around regenerating individuals (C); manual weed in a cicle around regenerating individuals and manuring (A); complete manual removal of weeds (L); and complete chemical removal of weeds (Q). All regenerating individuals higher than 20cm were identified and height measured. A total of eight measurements were taken within 16 months, in a 2 monthly basis interval. A total of 2696 individuals (5392 ind.ha-1) were sampled, with 128 (4,75%) dead individuals and 2568 living ones, represented by 90 morphospecies distributed within 69 genera and 32 botanical families (one remained unknown). Shannon ́s diversity index was calculated on H’=3.78 nats.individual-1, while Pielou ́s equability index was of J’=0.87. Regarding density enhancement analysis, (L) treatment presented better results when compared to control (T), probably because weed removal allowed better visualization of regenerating individuals. However, when it comes to height increase, this same treatment (L) presented the lowest values. Chemical weed control treatment (Q) did not affect natural regeneration, and height grothw was higher than those for control treatment (T), although the enhanced number of individuals was the lowest one. The second best treatment for height increase was (A), although in a similar way to treatment (C), density enhancement showed no significant difference when compared to (T). Only at the last taken measurement (C) treatment presented higher height increase than control.