Chuva de sementes em sistema agroflorestal e fragmento de floresta estacional semidecídua: a sustentabilidade de paisagens agrícolas

Abstract

Seed rain, as an ecological indicator of the self-maintenance processes of plant communities, and ecological flow in the landscape, plays an important role as one of the ways of evaluating the progress of ecological restoration. We aimed to characterize seed rain in a agroforestry system (AFS) implemented with the goal of restoring a Legal Reserve area and a a seasonal semideciduous forest fragment to propose evidence for the success of ecological restoration practices and understand how landscape dynamics relate to sustainability and land use. We measured the seed rain over two years, as well as producing an academic essay based on bibliographical research about sustainability in the context of ecological restoration. We conducted at the Agricultural Sciences Center, using 20 collectors, the collected seed rain was dried in an oven, organized into morphospecies, and identified to the lowest possible taxonomic level. We had a total of 25,149 samples, organized in 114 morphospecies that provided 17 identifications in the family category (10 genera and 22 species). We described differences in the absolute density over the two years for AFS (5,249 and 6,221, respectively), and the forest fragment (8,150 and 5,529, respectively). For relative density, 308.76 and 479.4 diaspores/m² in the first year, and in the second 325.24 and 365.94 diaspores/m². Thus, in the AFS seed rain, in both years, zoochorous tree species at the beginning of succession predominate, while in the forest fragment, anemochorous tree species at the beginning of succession. The proportion of autochthonous families was higher in both the areas in both years. The data explains how the diaspore community remains subordinated and conditioned to the ecological flows of a rural landscape predominantly focused on intensive and conventional production, however the similarity of the AFS seed rain in relation to the fragment indicates a progress of this restoration strategy. We highlighted the importance of describing the diaspore community, for monitoring, diagnosis and decision-making, for the conservation of native forest remnants and the success of restoration techniques.