Advanced search
Start date
Betweenand

Fragmentation of grassland areas: what is the consequence for anuran amphibian's metacommunities?

Grant number: 16/16899-0
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): January 01, 2017
Status:Discontinued
Field of knowledge:Biological Sciences - Ecology
Principal Investigator:Paulo Inácio de Knegt López de Prado
Grantee:Samanta Iop
Home Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Associated scholarship(s):19/08433-0 - Does landscape transformation drive biotic homogenization?: an analysis of beta-diversity of anurans in South Brazilian grasslands, BE.EP.PD

Abstract

Habitat fragmentation is defined as the process that converts an extensive original habitat area into small patches. This transformation generates ecological thresholds, i.e., critical levels of environmental conditions, such as the amount of natural habitat required to maintain the biological diversity. Thresholds can also be defined as points in which the abundance of species changes abruptly, generating inversions in ecological relationships, such as the one between specialists' and generalists' species. Physical percolation models and computer simulations show that a continuous original habitat begins to be fragmented into smaller, more isolated patches, when the percentage of the original habitat is lower than 60%, and that the critical point occurs in landscapes with original habitat cover lower than 20%. It is from this critical percentage that the distance between the original patches of habitat increases exponentially with fragmentation. Consequently, it is expected to occur a reduction in the dispersion of individuals between the habitat patches, increased species extinction by genetic drift within the patches, as well as environmental thresholds generating abrupt changes in ecological relationships. Studies about the effect of fragmentation on biodiversity have been predominantly carried out in forests, whereas the minimum amount of habitat needed to preserve the biodiversity in grassland biomes is largely unknown. Thus, this post-doctoral project will evaluate the relationship between the grassland fragmentation and the metacommunity of anuran amphibians from the Campos Sulinos. We choose the anurans as organisms of interest to answer the following questions related to the fragmentation of the Campos Sulinos: What is the minimum threshold of native grassland necessary to maintain the diversity of anurans? Is there a threshold that generates abrupt changes in the ecological relationships between specialists' and generalists' species? How do the processes of selection, drift and dispersion affect the functional attributes and the abundances of the species along the gradient of grassland fragmentation? This project will identify how predictable the effects of grassland fragmentation on anurans are, and will contribute to a central debate in Community Ecology: the importance of niche-based (selection) and neutral-based (drift and dispersion) processes on the structuring of metacommunities. (AU)