Abstract: Waterbird diversity was monitored annually using direct count method in 13 sampling sites of Nanji Wetland National Nature Reserve of Poyang Lake during the period of December 20 to January 10 from 2013 to 2018. A total of 129633 individuals of waterbirds belonging to 7 orders, 12 families and 45 species were recorded, with 11604 to 33053 individuals each year. Within all the recorded species, Siberian crane (Grus leucogeranus), Hooded crane (Grus monacha), and Oriental white stork (Ciconia boyciana) are listed in the first category of China’s〖JP〗 nationally protected bird species, while five other species are listed in the second category. A total of nine dominant species were recorded in this reserve, with Anatidae and Scolopacidae being the most abundant. More dominant species were recorded from 2013 to 2014 and 2017 to 2018. In contrast, only two dominant species were recorded from 2015 to 2016. Our results showed many waterbird groups were similar in abundance variation, indicating that appropriate water level can provide suitable wetland complex for various waterbird groups. The peak abundance of Podicipedidae occurred in correspondence with the low abundance of most waterbird groups, indicating that water level had significance in maintaining waterbird diversity. The similarity index of waterbird species among different sampling sites ranged from 0.51 to 0.91. Species richness and abundance increased during monitoring period due to the increased population size and encountering rate of Green winged teal (Anas crecca), Common pochard (Aythya ferina), and Pied avocet (Recurvirostra avosetta) during 2016 and 2018. The diversity index and evenness index reduced from 2015 to 2016 because Swan goose (Anser cygnoid) or Pied avocet were absolutely dominated in the community. This reserve is rich in waterbird diversity. Oriental white stork and White spoonbill (Platalea leucorodia) had large and stable population size. Cranes could almost be detected each year. This reserve played an important role in the maintenance of bird diversity and endangered waterbird conservation especially for Oriental white stork. The duration of this monitoring work was long, which preliminarily documents the patterns of population dynamics of dominant and nationally protected waterbirds and thus provides important scientific basis for waterbird conservation and habitat management in this reserve.

Key words: tree growth, dendrometer, initial size, topography., neighborhood competition, soil