Analysis of Bird Diversity Variation in Poyang Lake Based on Optimized Living Planet Index

The study focuses on the optimization of living planet index (LPI) to analyze the variation of biodiversity in fine scale. Comentropy and logarithm were utilized to generate these new indexes (LPIN1 and LPIN2). Using bootstrap method with Wilcoxon symbol rank test and 95% confidence interval, these optimized indexes were compared among different years. Based on the data on continuous bird monitoring in Poyang Lake from 2011 to 2017, the diversity of bird community was obtained by conventional method, LPI, LPIN1 and LPIN2. Results demonstrate that the two optimized indexes rose by 5% and ecosystem in Poyang Lake was stable. Besides, LPI index rose by 53%, which is not within the reasonable variation range of diversity index in Poyang Lake. Shannon-Wiener index and Simpson index indicate that the biodiversity was stable among different years, but failed to reflect the variation of the index. In contrast, two optimized new indexes can better delineate the variation trend of biodiversity in a fine scale and reflect the health of ecosystems in the Poyang Lake.