Monitoring the Landscape Pattern Dynamics and Driving Forces in Dongting
Lake Wetland in China Based on Landsat Images
Abstract
Dongting Lake wetland is a typical lake wetland in the Middle and Lower
Yangtze River Plain in China. Due to the influence of natural and human
activities, the landscape pattern has changed significantly. 12 Landsat
images of Dongting Lake wetland from 1991 to 2022 were extracted and
classified based on the CART decision tree method. The dynamic
characteristics of wetland vegetation spatial pattern changes were
analyzed using landscape pattern index, dynamic degree model and
transition matrix model. Redundancy analysis and grey correlation
analysis methods were used to explore the driving factors. The results
showed that from 1991 to 2022, the area of water and mudflat showed a
trend of first decreasing and then increasing due to the establishment
of the Three Gorges Dam. The mutual conversion of mudflat and water was
one of the forms of landscape transformation, while the mutual
conversion of sedge and reed area was the main trend of vegetation
landscape change. In the past 32 years, the fragmentation degree of
Dongting Lake wetland landscape has increased, the heterogeneity has
decreased and the landscape shape has become more complex. Water level
had the greatest contribution to wetland landscape fragmentation, with
the lower the water level, the greater the degree of landscape
fragmentation. Human activities were the most important driving force,
especially the policy changes in reed and woodland, as well as the
establishment of the Three Gorges Dam, which have a significant impact
on the landscape change pattern and ecological function of wetland. The
research results are of great significance for wetland ecological
restoration and environmental protection, providing scientific support
for China to achieve the goals of “carbon peak” and “carbon
neutrality”.