A review of drought adaptations in aquatic taxa: A buffer against climate change?

Authors: Kate S. Boersma

Year: 2014 (xlvi)

Abstract

Droughts in arid regions are increasing in frequency, intensity and duration, and these changes are predicted to threaten aquatic taxa. However, organisms inhabiting arid-land aquatic habitats are exposed to regular seasonal droughts and possess adaptations to survive short-term water shortage that may buffer populations against future drying. Unfortunately, relatively little is known about drought adaptations in arid-land aquatic taxa and thus we are unable to realistically predict population responses to future climate scenarios. Here I review the observational and experimental literature on adaptations to drying in five taxonomic groups (fish, amphibians, insects, crustaceans and molluscs) and identify commonalities across taxa. Adaptations fell into three main categories: behavioral, physiological, and phenological. Observational studies identified several commonalities, including drought escape behaviors such as burrowing and refuge use, high physiological tolerances for deteriorating water quality, and altered life history timing during drought years. In contrast, drought responses reported from manipulative experiments were much less uniform, both within and among taxa. These differences can in part be attributed to exactly which abiotic factors (e.g., water temperature, conductivity, water level) were manipulated by researchers in each of the experiments. Despite the paucity of literature and ongoing uncertainty over drought mechanisms, I argue that a synthesis across taxonomic groups is necessary in order to better predict biotic responses to intensifying drought regimes and identify future research directions.

Resumen

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