The Relationship Between NDVI Variation And Spatial Temporal Distribution Of Migratory Birds In The Poyang Lake Wetland

The wide circulation of the avian influenza virus brings more and more menace to the economy and human health. Migratory birds serve as natural carriers of the transregional dissemination of the avian influenza virus. The distribution variation of migratory birds in relation to the vegetation changes will contribute to evaluate the potential role of migroatory birds in the transmission of the virus spatially and temporally, thus to provide corresponding control strategies. In this study, SPOT-VGT imagerywere used to monitor vegetation coverage of the Poyang Lake wetland. NDVI serves as an indicator revealing vegetation change of the wetland. Spatial temporal trend of NDVI in the Poyang Lake wetland was analyzed. The spatial temporal distribution of migratory birds in the Poyang Lake from 1999 to 2006 was also investigated. Migratory birds were classified based on their feeding habits. We then analyzed the relationship between the NDVI change and the spatial distribution of migratory birds. The correlation coefficient between a time series of NDVI and different types of migratory birds were obtained.Our results showed that: (1) temporal change of NDVI in the Poyang Lake area showed an overall upward trend. All Natural Reserves in Poyang Lake area were impacted by both phenological and water level changes . The vegetation coverage of the national nature reserves includingNanjishan Nature Reserve, Kangshan Nature Reserve, and the northern Poyang Lake was higher than elsewhere in the region, indicated by higher NDVI. The vegetation coverage of most areas around the Poyang Lake has a positive slight increasing trend, but not statistically significant. (2) The total number of migratory birds and the number of bird species in the Poyang Lake area showed an overall increase over time. Poyang Lake region is a habor of migratory birds withmain habitats distributed in the National Nature Reserve, Kangshan Nature Reserve, and Duchang Reserve. (3) The NDVI value was correlated with the quantity of migratory birds with a correlation coefficient above 0.8. For inherbivorous birds, NDVI of the three areas, DuChang, Kangshan, and Baishazhou Reserve, was significantly correlated with the quantity of migratory birds respectively.This association study between the NDVI and the spatial temporal distribution of migratory birds in the Poyang Lake wetland provides us a theoretical basis for the protection of migratory birds in the Poyang Lake area, and the management of the Poyang Lake Nature Reserve. As a preliminary study on the role that migratory birds play in the circulation of the avian influenza virus, this will also provide policy recommendations to make effective prevention and control strategies.