Forest dynamics and aboveground biomass balance of Atlantic Forest across an elevation gradient of the Serra do Mar state park

Author(s)

Marcos Augusto da Silva Scaranello

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2015-08-18

Examining board members

Carlos Alfredo Joly; João Luis Ferreira Batista; Luiz Eduardo Oliveira e Cruz de Aragão; Mercedes Maria da Cunha Bustamante; Flavio Antonio Maës dos Santos

• Advisor: Simone Aparecida Vieira; Carlos Alfredo Joly

Abstract

Understanding how the dynamics and productivity of the tree community in tropical forests change with an elevation gradient can help to produce insights about how these ecosystems will behave under the influence of climate change in the future. This thesis assessed the dynamics and productivity of the Atlantic forest along the elevation gradient of the Serra do Mar with a focus on functional ecology, using 13 permanent plots of 1-ha. We represented the forest dynamics as growth, mortality and recruitment of tree community; and productivity as the increment in biomass of the living individual trees and their net change. We used wood density as a key functional trait due to its ability to integrate the trade-off between growth and survival of tree species in tropical forests. As we used a functional approach, we evaluate in the first chapter the potential of using continuous probability distributions to describe one of the important aspects of functional diversity: the functional divergence. We found that the best probability model to describe the wood density data, among the tested, was Weibull and its shape parameter was an important descriptor of traditional indices describing the functional divergence in forest communities. In the second chapter we evaluate the functional convergence and patterns of wood density divergence in response to the elevation gradient. We did not find convergence of wood density both with respect to elevation and slope gradient found along the gradient. The pattern of divergence in community scale, on the other hand, changed along the gradient and was related to the slope of the terrain and the gap phase - defined here as the natural regime of local disturbance and subsequent regeneration. We found communities with lower functional divergence in steep slopes and advanced gap phase. In the third chapter we assessed the growth at multiple scales along the elevation gradient. We tested the relationship between the wood density and growth at species level and it was site-specific, in only 4 of the 13 permanent plots. We also investigated the determinants of growth at the community-level and found an effect of SES.PW - the standardized effect of mean pairwise trait distance, a measure of divergence - on the absolute and relative growth at the community-level. Communities with lower functional divergence showed the lowest growth rates when compared to communities with greater functional divergence. Finally, in the fourth and final chapter we evaluated the mortality and recruitment at multiple scales along the elevation gradient. In addition, we evaluated the influence of turnover - the rate at which trees die and recruit in a forest community - on above-ground biomass net change. We found that the wood density was an important descriptor of mortality at the individual and species level, but not at community-level. At the community-level, the gap phase was an important descriptor of mortality, recruitment and turnover. Finally, we found that forest areas with the lowest turnover rates accumulated more above ground biomass across the elevation gradient. The very steep areas are acting as a determiner of species niche, harboring communities with low dynamics and with advanced gap phase. Consequently, these communities show lower mortality and turnover rates, grow slowly and accumulate more above ground biomass (AU)

• FAPESP's process: 11/11604-9 - Patterns of dynamic and productivity of functional groups of trees and palms in Tropical Atlantic forest along an elevational gradient of Serra do Mar
• Grantee: Marcos Augusto da Silva Scaranello
• Support Opportunities: Scholarships in Brazil - Doctorate