Negative effects of farmland expansion on multi-species landscape connectivity in a tropical region in Southwest China

Abstract

The expansion of farmland has negative effects on the natural landscape patterns supporting ecological processes, which in turn can be reflected in changes in the landscape connectivity for animal movements. There is an urgent need to address the issue of the changes to landscape connectivity caused by farmland expansion, especially in tropical areas in Southwest China that have high biodiversity levels and intense human cultivation. Using Menghai County in Xishuangbanna as the study area, six landscape pattern indexes were used to evaluate the landscape patterns and fragmentation based on land use data, and a multi-species circuit theory method was used to quantitatively analyze the changes and spatial variability in landscape connectivity. The results showed that the encroachment of farmland greatly increased the degree of landscape fragmentation. Current density maps of circuit connectivity based on multi-species showed that the spatial differences in the landscape ecological networks were obvious. The key corridors identified by the Zonation model showed that the landscape connectivity in the western area of Menghai County was higher than that in the central area. Comparing the changes between different periods, the maximum current declined the most, with a loss of nearly 25%, from 1995 to 2000. By 2000, the key corridors in the central region had almost completely disappeared. The above information indicated that the farmland expansion led to fragmentation, influenced the movement processes of the regional wild species and reduced the degree of landscape connectivity. This study on the evaluation of the impact of farmland expansion will improve the understanding of the effects of human activities on regional landscape connectivity and provide an operational approach to conservation planning.