Salinisation of arid temporary pools alters crustacean hatching success but not phenology dynamics

Abstract The widespread acceleration of freshwater salinisation due to human activities, such as pollution, resource extraction and urbanisation coupled with climate change, poses a significant threat aquatic ecosystems. Limited work has been directed towards effects in temporary wetland systems. These systems are characterised by unique crustacean communities reliant on dormant egg production. We assessed from semi–arid pans the Khakhea–Bray Transboundary Aquifer region South Africa using laboratory–based approach. Sediment containing resting eggs was exposed water varying salinities (0‒10 ppt), emergent hatchlings were over 30–day hydroperiod. At 2.5 ppt above, there decreases taxa richness abundance. Spinicaudata Ostracoda most sensitive high salinities. Cladocera, Copepoda, Notostraca Anostraca had shallower salinity, but hatchability still fell rapidly. There limited effect community hatching phenology dynamics all showing reduced time overall, exception Cladocera which exhibited clear unimodal response, peaking around 20 days post‒inundation. This suggests that main impact these will be reductions success hence recruitment, leading changes predation pressures, food web structure functioning ecosystems, implications for associated ecosystem services.