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Effects of land use intensification on freshwater community similarity and beta diversity

Grant number: 18/07714-2
Support type:Scholarships abroad - Research Internship - Doctorate
Effective date (Start): November 01, 2018
Effective date (End): October 31, 2019
Field of knowledge:Biological Sciences - Ecology
Principal Investigator:Luis Cesar Schiesari
Grantee:Rodolfo Mei Pelinson
Supervisor abroad: Mathew Albert Leibold
Home Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Local de pesquisa : University of Florida, Gainesville (UF), United States  
Associated to the scholarship:17/04122-4 - Effects of local processes and spatial isolation on aquatic community assembly: a simulation of land use intensification, BP.DR

Abstract

The metacommunity is one of the most promising frameworks for understanding the consequences of environmental change on biodiversity because it addresses how spatial isolation and different selective pressures affect similarity among communities. Here we intend to use the metacommunity framework to understand how different vectors of land use intensification affects similarity among freshwater communities. Specifically, we simulated the stocking of predatory fish for aquaculture and chemical land use intensification in two field experiments manipulating constructed artificial ponds. In the first experiment we crossed the presence of the Redbreast Tilapia with three levels of spatial isolation from a source of insect colonists. In the second experiment we crossed the same levels of isolation with three levels of chemical intensification: (1) control (no chemical treatment), (2) addition of fertilizers only (pasture treatment); (3) addition of fertilizers, insecticide and herbicide (sugar cane treatment). Our main expectations are that deleterious selective pressures, such as the presence of predatory fish or pesticides, would make communities more similar to each other because these deterministic forces would not allow communities to drift to different community structures due to stochastic events. On the other hand, the nutrient enrichment promoted by fertilizers should release species from competition for food resources and allow species population size and occurrence to drift more due to stochastic events. Finally, habitat isolation should decrease community similarity due to rarity of recolonization events following stochastic local extinctions. (AU)