Water availability determines the richness and density of fig trees within Brazilian semideciduous forest landscapes

Author(s)

Mello Coelho, Luis Francisco ; Ribeiro, Milton Cezar ; Santinelo Pereira, Rodrigo Augusto

• Document type: Journal article
• Source: ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY; v. 57, p. 8-pg., 2014-05-01.

Abstract

The success of fig trees in tropical ecosystems is evidenced by the great diversity (+750 species) and wide geographic distribution of the genus. We assessed the contribution of environmental variables on the species richness and density of fig trees in fragments of seasonal semideciduous forest (SSF) in Brazil. We assessed 20 forest fragments in three regions in Sao Paulo State, Brazil. Fig tree richness and density was estimated in rectangular plots, comprising 31.4 ha sampled. Both richness and fig tree density were linearly modeled as function of variables representing (1) fragment metrics, (2) forest structure, and (3) landscape metrics expressing water drainage in the fragments. Model selection was performed by comparing the AIC values (Akaike Information Criterion) and the relative weight of each model (wAIC). Both species richness and fig tree density were better explained by the water availability in the fragment (meter of streams/ha): wAIC(richness) = 0.45, wAIC(density) = 0.96. The remaining variables related to anthropic perturbation and forest structure were of little weight in the models. The rainfall seasonality in SSF seems to select for both establishment strategies and morphological adaptations in the hemiepiphytic fig tree species. In the studied SSF, hemiepiphytes established at lower heights in their host trees than reported for fig trees in evergreen rainforests. Some hemiepiphytic fig species evolved superficial roots extending up to 100 m from their trunks, resulting in hectare-scale root zones that allow them to efficiently forage water and soil nutrients. The community of fig trees was robust to variation in forest structure and conservation level of SSF fragments, making this group of plants an important element for the functioning of seasonal tropical forests. (C) 2013 Elsevier Masson SAS. All rights reserved. (AU)

• FAPESP's process: 04/10299-4 - Effects of the forest fragmentation in the State of São Paulo and other regions of the South and Southeast of the country in the functioning of populations of fig trees and in the fig-wasp mutualism of figs
• Grantee: Rodrigo Augusto Santinelo Pereira
• Support Opportunities: BIOTA-FAPESP Program - Young Investigators Grants