Observations on the hatching dynamics and phenology of co-occurring large branchiopods from a small temporary pool in western India usingex situsediment rehydration

Abstract

Sediment rehydration is a useful technique to study various ecological aspects of resting egg banks of many aquatic invertebrates, but there is a paucity of such studies from the Asian region as compared with other regions. Hence, using a tropical temporary pool as a study system, and with successive, ex situ hydrations of sediments, we studied (1) the hatching phenology and dynamics of co-occurring Notostraca and Anostraca, and (2) the effects of cyclical hydroperiods on these dynamics. Ten species of different aquatic taxa emerged from the sediments. Among the large branchiopods, the primary consumer Streptocephalus dichotomus (Anostraca) was more numerous than the predatory Triops granarius (Notostraca). However, while differing in ecological roles, the two species exhibited similar phenology and hatching strategies, with nauplii emerging in similar proportions across hydration treatments, peaking at the first hydration (∼90%), and decreasing through the third. Hatching began on day 1 in all hydrations and peaked on days 2–3. Hatching duration decreased with successive hydrations, being the longest for the first hydration. These species are important to the food chain associated with temporary aquatic habitats, which are relatively understudied in the Indian context. Laboratory-based studies, in combination with field data can help understand the ecology of the associated community. We highlight the need for such studies that can prove important for conservation of such habitats, when their destruction is rampant and undocumented.