SPATIAL DISTRIBUTION CHARACTERISTICS OF ROTIFER RESTING EGGS IN SUB-LAKES OF THE POYANG LAKE WETLAND AREA DURING THE DRY SEASON

Our study examined spatial distribution differences of rotifer resting eggs (RRE) in lakes of the Poyang Lake Wetland Area during dry season, January 2015. Field sampling was conducted in both Nanshen Lake and Baisha Lake. We found that densities of RRE in different habitats were significantly different (P<0.05), and their distribution had an obvious gradient. The highest mean density was in the marshland vegetation area of Nanshen Lake, where it was (3.34±1.28) ind./cm³. The density of resting eggs in the Zizania latifolia area was up to 5.45 ind./cm³. The density of RRE was different spatially, with the greatest in the vegetation area, then in the muddy area, and then the lowest in the water area. ANOVAs results showed that water depth, vegetation, and sediment had significant effects on RRE (P=0.001, P=0.007, P<0.001, respectively). The trend of resting egg densities in different aquatic habitats was: emergent aquatic plant > marshland vegetation > floating-leaf plants > submerged plants. The distribution of RRE in areas of different water depths was inconsistent. The density of RRE was higher in the hard than soft sediment.