Jm. Langley et al., Hatching from the sediment egg-bank, or aerial dispersing? the use of mesocosms in assessing rotifer biodiversity, HYDROBIOL, 446, 2001, pp. 203-211
Rotifer emergence from dry billabong sediments was studied from 3 sites on
the River Murray floodplain, near Wodonga, northern Victoria, Australia. Th
e sites had different flood histories, ranging from annual to approximately
25-year flooding intervals. Half of each sediment type was sterilized by g
amma -radiation to contrast the contribution of recruitment from the egg ba
nk with recruitment from passive dispersal. A series of mesocosms was emplo
yed to assess differences between treatments, i.e. sediment sterilization a
nd flood history. Analysis by Canonical Correspondence Analysis and Similar
ity Percentages suggested that some species were passively dispersed. Of th
e 54 species colonizing after 35 days, four were undescribed, one was a new
record to Australia, three species had previously been recorded only from
Tasmania and five more were new to the study area. Overall, 22% of species
were previously unrecorded from the study area. This suggests that habitat
poor mesocosms, may be more successful in locating passively dispersed taxa
than examination of natural temporary waters.