Regional patterns and controls of natural grassland fragmentation in Uruguay

Abstract

The replacement and fragmentation of ecosystems due to agricultural expansion and intensification processes are the greatest threats to biodiversity and ecosystem services in the Americas. In Uruguay, grasslands are the most transformed ecosystems, but their fragmentation has been scarcely studied. The objective of this work was to characterize the fragmentation in the main grassland regions of Uruguay, identify the most fragmented sites, and the controls that explain such fragmentation. Five fragmentation metrics were calculated from land cover maps and multiple linear regression models were developed to analyze the relationship between fragmentation and a set of environmental and anthropic variables. The proportion of grasslands varied between 40 and 75.8% depending on the region, and the degree of fragmentation differed between them. The regions with the highest proportion of grasslands had higher effective mesh sizes and average patch sizes. The number and factors controlling fragmentation also varied between regions. Multiple linear regression models show that between 36 and 46% of the variability in fragmentation can be explained by a set of factors associated with the establishment of agricultural and forest crops. These results provide key information for the design of grassland conservation policies in Uruguay.