Biomass and biodiversity modulating ecosystem functioning

Abstract

Carbon uptake by primary biomass growth is a vital process for biodiversity regulation, which initiates the flow of carbon through food webs. This process is modulated by climatic and edaphic conditions and by plant traits, shaping the functional diversity. On the other hand, the characteristics of species interaction networks (i.e. herbivory, pollination and dispersion of fruits and seeds) can also affect primary production. Such relations have been critically influenced by human activities. The replacement of native ecosystems by agroecosystems changes the composition of the primary community and its functional diversity, affecting primary biomass and habitat structure at all trophic levels. Assessing the growth and fluxes of primary biomass at different time and spatial scales is a promising, still under-used, approach to guide conservation and management of native fauna in human-altered landscapes. To do so, it is necessary to understand the mechanisms driving the interdependence of biomass stocks between animal and plants (amount and composition). The prime aim of this study is to compare the abundance and composition of bird and small mammal communities under different conditions of density and composition of tree biomass within landscapes dominated by monocultures. We chose a study region (Lençóis Paulista-SP and Angatuba-SP), which is marked by the transition between the Atlantic Forest and the Cerrado and also by the contrast between sugarcane and eucalyptus plantations. Our analyses combine remotely sensed data and biological surveys (vegetation plots from the present study, birds and small mammals surveyed by other researchers from the same research program), as well as compiled secondary data on physical attributes of landscapes, and on biological attributes of the sampled species. These datasets will be analysed and compared in four stages: a) based on allometric estimates of aboveground biomass, we will quantify and compare the primary biomass distribution within landscapes dominated by sugarcane and eucalyptus crops; b) after developing a spatial model for aboveground biomass with remotely sensed data and field biomass measurements, we will investigate the relationship between primary biomass density and abundance of the groups of birds and small mammals within studied landscapes; c) by comparing spatial models of biomass density and distribution of birds and small mammals, we will test aboveground biomass as a predictor of animal species composition (birds and small mammals); d) by including secondary data gathered on environmental covariates and functional attributes in our analysis, we will investigate the interdependence between the functional diversity of trees and the abundance of observed animal species/groups. (AU)