Characteristics and driving mechanism of wetland landscape pattern change in karst region of southwest China over past 35 years: A case study of Caohai wetland in Guizhou

To uncover the process of land use change and its driving mechanism of typical wetland ecosystems in the karst region, this thesis conducts a case study on Caohai National Nature Reserve (hereafter referred to as Caohai). With the support of geo-information technology and the landscape index analysis method, it quantitatively analyzes the magnitudes, speed, and landscape patterns of land use changes over 35 years from 1985 to 2020 using continuous remote sensing images. The results show that the land use structure of Caohai has mainly undergone mutual conversion between farmland and wetland. Before 2005, 164.60 ha of farmland were converted to wetland, from 2005 to 2015, 451.79 ha of wetland were converted to farmland, and from 2015 to 2020, 979.62 ha of farmland were transformed into wetland. The trend for construction land was to decrease first and then increase, with increased construction land primarily coming from farmland and partially from shrubland and forestland. The spatial connectivity of landscape distribution showed a slow decrease to a rapid decrease, then increased and reduced again, while diversity and evenness showed the opposite trend. Rational policies and urban construction planning are essential measures for protecting wetland ecosystems in the karst region.