Beyond the boundaries: Do spatio-temporal trajectories of land-use change and cross boundary effects shape the diversity of woody species in Uruguayan native forests?

Abstract

Environmental management often lacks a harmonization across scales and beyond boundaries of the land with changed use. As an example, extensive areas of Uruguayan grassland have been transformed into crop and timber plantations in the past decades, but little is known about the possible impacts of these changes on neighboring native forests. We explore how the diversity of native forests differs in relation to land-use change trajectories, from grassland to monocultures, in the surrounding landscapes. We recorded woody species in 32 different native forest plots in Uruguay. Using Landsat images, we created land-use maps in a buffer of 3 km around each plot for the years 1986/1987, 1996/1997, 2006/2007 and 2016/2017. We calculated trajectories of changes regarding the percentage of cover per land use, the landscape shape and aggregation index for native forests, grassland, timber plantations and crops. Trajectories were explored based on the slope of the generalized linear model correlated with woody species composition. Landscape covered by native forests, timber plantations and crops increased whereas grassland cover decreased. Large and interconnected native forests in a landscape dominated by grasslands harbor a high diversity of woody species. Disaggregation of grassland resulted in a decrease in richness and diversity of woody species. The history of surrounding landscape determines diversity of native forests. We observed cross boundary effects of neighboring land uses on native forests. These effects have to be considered in all measures of environmental management to reduce the trade-offs between biodiversity conservation and economic profit. Nevertheless, other parameter such as climate and soil interplay, override and alter the effects of land use history and management.