Forest restoration in an indigenous land considering a forest remnant influence (Avaí, São Paulo State, Brazil)
In the Araribá indigenous land in Avai, São Paulo State, Brazil, the researchers attempted to restart and support natural regeneration on highly deforested land dominated by African grasses Urochloa brizantha and Rhyncheiytrum repens. These grasses, believed introduced through cattle dung, completely covered the area save for a few secondary forest fragments. The land had been used recently for minor cattle grazing but 12 years prior for intensive Manihot esculenta cultivation. The study aimed to examine for the presence of propugule sources to jump-start the restoration of forest inside the indigenous lands, and if the proximity to forest fragments could speed up the process. They used pasture plots adjacent to forest fragments as their study areas.
Goals & Methods
These objectives were formulated to fit a larger goal of understanding the natural regeneration potential of pasture adjacent to forest remnants and to pave the way for future restoration projects. To achieve their objectives, the study examined seed rain (to investigate distribution patterns and the affect of proximity to forest fragments and for richness and abundance rates of propulgules), the seed bank (richness and abundance rates), and regeneration of woody plants – measuring heights within 20m by 15m plots for 2 years (to examine diversity, classify habitats and understand dispersion regimes).
Conclusions & Takeaways
Low animal dispersion rates amongst species analyzed in the seed rain and seed bank was consistent with expectations of heavily disturbed areas: without the animal dispersers to do their work, the zoochorous species die off and are replaced by anemochorous species. Over the course of two years of returning twice a year (ends of the rainy and dry seasons), the woody shrubs grew intensively, largely limited to the invasive species. Despite setting themselves up as just doing the research to prepare the methodology for future restoration projects, this project actually set in motion the initial assisted-regeneration methods of reforestation by sequestering pasture from cattle and assisting the regeneration of woody invasive species. These species could serve as nurse species to bring in bats and birds and pave the way for native species regeneration and restoration. The study recommends the local people set to digging up the non-germinating soil to stimulate the seed bank, and to continue monitoring and nurturing the woody shrubs until shade cover overcomes the herbaceous grasses. Only after a canopy is established should they introduce valuable species and native, later-successional species to phase out the exotic invader tree species.
Forest restoration in an indigenous land considering a forest remnant influence (Avaí, São Paulo State, Brazil). Forest Ecology and Management. 2008;255:513–521. doi:10.1016/j.foreco.2007.09.020..
- Laboratório de Ecologia e Restauração Florestal, Universidade de São Paulo, ESALQ/LCB, SP, Brazil