The Impact of Urban Expansion on Plant Diversity Change in Karst Regions of Southwest China

Biodiversity is vital for the integrity and stability of ecosystems and sustainable development. Karst regions of Southwest China is featured for undulating and broken karst terrain as well as high plant diversity. Land use changes induced by the growing population and expanding human settlement have threatened biodiversity preservation in this region. However, the impact of urban expansion on plant diversity remains unclear here. This study focuses on how expanding countryside landscapes affect the recovery rate of plant diversity and demonstrate how urban expansion affects plant diversity conservation in karst regions of Southwest China. In situ biodiversity investigations and multisource remote sensing images were combined to analyze the role of human settlement evolution in the conservation of plant diversity using descriptive statistics and regression analysis. Unmanned vehicle images, historical aerial photographs, and long-term remote sensing images were used to observe the human settlement pattern changes over 40 yr and found that plant diversity is restored faster in countryside ecosystems than in island ecosystems restricted by water. Forests, however, contribute the most to plant diversity conservation in both ecosystems. While the forest area is stable during urban expansion, massive forest patches play an essential role in plant diversity conservation. Arable lands and grasslands shrank but with a fragmenting trend, which was conducive to preserving plant diversity, whereas increased and regularized large patches of built-up areas were not beneficial to plant diversity. Accordingly, forest protection should be prioritized to coordinate future socioeconomic development and plant diversity conservation in karst and broader regions. Furthermore, large built-up patches should be limited, and the irregularity should be improved during urban expansion. Irregular shaped cultivated land and grassland were suggested to promote biological information exchanges as landscape corridors.