36 years of dynamics of one hectare of a semideciduous seasonal forest

• Grant number: 20/05533-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2020
• End date: April 30, 2023
• Field of knowledge: Biological Sciences - Ecology - Ecosystems Ecology
• Principal Investigator: Ricardo Ribeiro Rodrigues
• Grantee: Thiago Almeida Bueno
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 18/18416-2 - Understanding restored forests for benefiting people and nature - NewFor, AP.BTA.TEM
• Associated scholarship(s): 22/03305-6 - What almost 40 years of monitoring reveal about the dynamics and sustainability of a conservation unit in the Atlantic Forest, BE.EP.IC

Abstract

This proposal aims to remedy, 36 years after the first measurement, an urban Semideciduous Seasonal Forest fragment spatially isolated from other fragments for at least 100 years, which has undergone significant changes in its composition and structure over time. The purpose of this remediation is to generate data that will allow the temporal changes (36 years) of structure (basal area and height) and richness of this small urban forest fragment (252 ha) to be explained, to identify patterns of these changes, and to compare these patterns with temporal changes of large protected non-urban forest fragments in Conservation Units, with data already available in the literature and/or database. In the interior of this semideciduous seasonal forest fragment in Campinas, SP (Santa Genebra Municipal Reserve-RMSG), with 252 ha, a permanent plot of 1 ha was installed in 1983 in a stretch of forest in an advanced successional stage, in the central portion of the fragment, to mitigate the edge effects. In this 1983 assessment, trees with 15 cm stem circumference (CAP) were mapped, their circumference and heights recorded, and the species identified. This permanent portion was remedied in four more re-evaluations from 1983 to 2004, adding up to a period of 20.6 years of forest dynamics assessment. During this time of assessment (20.6 years), there was a significant decrease in the number of individuals, in the basal area per plot, as well as in the height of the trees sampled and a negative net density of individuals, with reduced provision of ecosystem services. There were numerical reductions in the canopy populations and also drastic reduction in the sub canopy populations, compromising the perpetuation of this fragment. The change in the composition of regenerating individuals signalled a change in the future canopy, which will result in a successional regression. The dynamics in RMSG portrayed a structural decline resulting from the combination of several internal and anthropic factors. However, the result obtained from the four samples did not allow a conclusive analysis of community degradation trends. Thus, this CI aims to re-sample 36 years after the first measurement, a forest community protected as a CU for at least 40 years to, based on the patterns of changes identified, discuss changes in the provision of ecosystem services (biodiversity and carbon) and discuss the possibility of adopting adaptive management actions that reverse the effects of these changes, since this is the reality of the vast majority of forest fragments in southeastern Brazil. These results may contribute to the scientific support of good public policies for the conservation and recovery of forest fragments in Brazil, which is a requirement of Brazilian environmental law (Law 12.651, March 2012).