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Optimising hydrological conditions to sustain wintering waterbird populations in P oyang L ake N ational N atural R eserve: implications for dam operations
Author(s) -
Wang Yuyu,
Jia Yifei,
Guan Lei,
Lu Cai,
Lei Guangchun,
Wen Li,
Liu Guanhua
Publication year - 2013
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/fwb.12216
Subject(s) - environmental science , tributary , hydrology (agriculture) , dry season , population , floodplain , ecology , geography , biology , demography , cartography , geotechnical engineering , sociology , engineering
SummaryP oyang L ake is the largest freshwater lake in C hina and is of global importance for the conservation of migratory waterbirds of the E ast A sian – A ustralasian F lyway. Recent dam construction on the Y angtze R iver and its tributaries for agriculture and hydroelectric power has affected the hydrological regimes in downstream lakes. The Three G orges D am changed the hydrological regime of downstream lakes by reducing wet season flooding and expanding water storage in the dry season. Despite the critical role of P oyang L ake in regional and global biodiversity conservation and the potential adverse ecological impacts of the Three Gorges Dam on downstream lakes, there have been few studies of the hydrological requirements of wintering waterbirds in the middle Y angtze floodplains. We assembled a predictor matrix including three hydrological variables (annual inflow, maximum water level in high water season or M ax WL and minimum water level in low water season or M in WL ) and two climatic variables (annual rainfall and biological cumulative temperature or B io T ). Using the predictor matrix and annual waterbird census, we built group‐specific generalised additive models ( GAM ) to investigate how waterbird population variations were related to climatic and hydrological factors in the P oyang L ake N ational N atural R eserve. We then used the modelled predictor–response curves to identify the optimal lake water levels for each waterbird group. The community‐level model selected group and the group‐varying‐coefficient term of B io T , I nflow and M ax WL as explanatory variables. At group level, tuber eaters and sedge foragers responded positively to B io T and M in WL . Seed eaters, invertebrate eaters and fish eaters responded positively to Inflow and negatively to M ax WL and M in WL . Based on the modelled predictor–response curves, we propose the following optimal water level ranges for P oyang L ake wintering waterbird conservation: a) maximum high water season level should be less than 17.4 m; and b) minimum low water level should be between 8.2 m and 8.8 m.