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Food constraints explain the restricted distribution of wintering L esser W hite‐fronted G eese A nser erythropus in C hina
Author(s) -
Wang Xin,
Fox Anthony D.,
Cong Peihao,
Cao Lei
Publication year - 2013
Publication title -
ibis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 80
eISSN - 1474-919X
pISSN - 0019-1019
DOI - 10.1111/ibi.12039
Subject(s) - ecology , flyway , habitat , geography , population , carex , biology , fishery , demography , sociology
More than 90% of the L esser W hite‐fronted G eese A nser erythropus in the E astern P alearctic flyway population winter at E ast D ongting L ake, C hina. To explain this restricted distribution and to understand better the winter feeding ecology and habitat requirements of this poorly known species, we assessed their food availability, diet and energy budgets at this site through two winters. L esser W hite‐fronted G eese maintained a positive energy budget when feeding on above‐ground green production of E leocharis and A lopecurus in recessional grasslands in autumn and spring to accumulate fat stores. Such food was severely depleted by late November and showed no growth in mid‐winter. G eese fed on more extensive old‐growth C arex sedge meadows in mid‐winter where they were in energy deficit and depleted endogenous fat stores. G eese failed to accumulate autumn fat stores in one year when high water levels prevented the Geese from using recessional grassland feeding areas. Fat stores remained lower throughout that winter and Geese left for breeding areas later in spring than in the previous year, perhaps reflecting the need to gain threshold fat stores for migration. Sedge meadows are widespread at other Y angtze R iver floodplain wetlands, but recessional grasslands are rare and perhaps restricted to parts of E ast D ongting L ake, which would explain the highly localized distribution of L esser W hite‐fronted G eese in C hina and their heavy use of these habitats at this site. Sympathetic management of water tables is essential to maintain the recessional grasslands in the best condition for Geese. Regular depletion of fat stores whilst grazing sedge meadows in mid‐winter also underlines the need to protect the species from unnecessary anthropogenic disturbances that enhance energy expenditure. The specialized diet of the L esser W hite‐fronted G oose may explain its highly restricted winter distribution and global rarity.