sem 160721


Diverse freshwater invertebrate communities persist in temporary rivers despite regular water loss. Communities are described as resilient, meaning that they recover quickly after flow returns due to the arrival of recolonists from outside of the temporary reach. In contrast, resistance to drying – the ability to survive in dry sediments – is typically considered low. However, recent research – in particular, sediment rehydration experiments – has demonstrated that many taxa survive within a ‘seedbank’ of viable eggs, juveniles and adults, and resistance may therefore have been underestimated. We examined the seedbank in the sediments of a temporary river in central England in multiple years, including wet, normal, and drought years. In a separate study, we conducted a meta-analysis to compare seedbank assemblages in relation to environmental conditions across climate zones. Results indicate that sediment moisture content is a key determinant of seedbank richness, and these assemblages can therefore be particularly diverse in temperate zones – but drought events pose a threat to seedbank integrity.