个 / m 2 和 (25.78 ±3.97) 个 / m 2 ,显著高于 4 月份的密度 (2.52 ±0.91) 个 / m 2 和 (4.76 ±1.17) 个 / m 2 ( Z = 3.712, P<0.01; Z = 5.738, P<0.01) ;10 月份两种植物冬芽的生物量 ( 干重) 分别为 (3.07 ±0.65) g / m 2 和 (5.43 ±0.75) g / m 2 ,也显著高于 4 月份平均生物量 (0.89 ±0.35) g / m 2 和 (2.21 ±0.59) g / m 2 ( Z = 3.118, P<0.01; Z = 3.821, P<0.01) 。 10 月份罗氏轮叶黑藻冬芽密度显著高于刺苦 草冬芽密度 ( Z = 3.466, P<0.01) ,但 4 月份两种冬芽密度之间无显著差异 ( Z = 1.677, P = 0.09) 。 丰水期 ( 4-9 月) 能形成冬 芽的两种沉水植物的平均水深分别为 (2.63 ±0.15) m 和 (2.61 ±0.12) m。 沙湖冬季刺苦草冬芽和罗氏轮叶黑藻冬芽是植食性 水鸟的重要食物。 估计水鸟越冬期在沙湖摄取两种植物冬芽约 1.04伊10 8 个,共 1.9伊10 4 kg。 Abstract: Winter buds of submerged macrophytes are main food for herbivorous waterfowl in winter. Poyang Lake is important wintering sites for waterbirds in the Yangtze basin. Understanding the spatial distribution of winter buds and their food contribution for herbivorous waterfowl can provide scientific basis for waterfowl conservation and lake management. We studied species composition, individual density, and spatial distribution of winter buds using quadrate method in October 2012 and April 2013 in Shahu Lake, a sub鄄lake of Poyang Lake. Winter buds of two submerged plant species, Vallisneria spinulosa and Hydrilla verticillata var. rosburghii, were recorded. The average density of winter buds of Vallisneria spinulosa http: / / www.ecologica.cn was (9.53 ±1.73) ind / m 2 and of Hydrilla verticillata var. rosburghii ( 25.78 ±3.97) ind / m 2 in October, which were also significantly higher than that in April ( (2.52 ±0.91) ind / m 2 for Vallisneria spinulosa and (4.76 ±1.17) ind / m 2 for Hydrilla verticillata var. rosburghii) ( Z = 3.712, P<0.01 and Z = 5.738, P<0.01, respectively) . The average biomass of winter buds ( dry weight) of Vallisneria spinulosa was (3.07 ±0.65) g / m 2 and of Hydrilla verticillata var. rosburghii (5.43 ±0.75) g / m 2 in October, which were significantly higher than that in April ( (0.89 ±0.35) g / m 2 and (2.21 ±0.59) g / m 2 , respectively) ( Z = 3.118, P< 0. 01; Z = 3. 821, P < 0. 01) . The density of Hydrilla verticillata var. rosburghii winter buds was significantly higher than Vallisneria spinulosa winter buds in October ( Z = 3.466, P<0.01) while there was no significant difference in the density of the two species of winter buds in April ( Z = 1. 677, P = 0. 09) . The average depth that suitable for the formation of winter buds of the two species of submerged plants was (2.63 ±0.15) m and (2.61 ±0.12) m, respectively, in flooding season ( from April to September) . Winter buds of Vallisneria spinulosa and Hydrilla verticillata var. rosburghii are important food for herbivorous waterfowl in Shahu Lake. It is estimated that waterfowl consumed 1.04伊10 8 ind (1.9伊10 4 kg) of the two species of winter buds in winter.

No abstract