Adaptation, phenology and disturbance of macroinvertebrates in temporary water bodies

The temporal transition of species dominance following disturbances is strongly influenced by taxon life histories. In temporary water bodies, seasonal progression can be rapid. The community response of aquatic littoral invertebrate communities to disturbance was measured across four temporary water bodies (turloughs) representing a hydroperiod gradient in the karst landscape of western Ireland. Three distinct turlough wet-phases were identified based on macroinvertebrate taxon richness and community composition: filling, aquatic and drying phase. Invertebrates able to recolonise the turlough environment quickly upon flooding from refugia (e.g. sink-holes or little puddles) or resting stages within the turlough basin demonstrated highest proportion in abundances during the initial filling phase. Over time, the number of actively dispersing invertebrates, generally occupying turloughs only for a part of their life-cycle, increased. Hydroperiod had a significant effect on macroinvertebrate taxon richness, with short hydroperiods supporting low faunal diversity. Influence of hydrological disturbance generally decreased with progression of the annual wet phase, indicated by a decrease in taxon richness variation and an increase of biodiversity with time. Our study highlights the importance of life-cycle strategies of species for the occurrence of fairly predictable and periodically occurring seasonal patterns, and emphasizes the importance of ecological disturbances for colonisation cycles.