Potential for water-resource infrastructure to act as refuge habitat

• Climate change and extractions will reduce the size and permanence of water bodies.
• We assessed two types of water-resource storages for potential as refuge habitat.
• Fish, frogs and zooplankton were similar in storages and natural water bodies.
• Water reclamation and raw water storages have potential as refuge during drought.

Permanent sources of natural water are expected to decline in Mediterranean-climate regions under future climate change. Therefore, stable water bodies that act as refuge habitats will become increasingly important to the maintenance of freshwater biodiversity. Man-made water bodies such as those associated with water-resource infrastructure could contribute to the available refuge habitat but little is known about fish, zooplankton and frog assemblages in such water bodies. We quantified the diversity and abundance of fish, zooplankton and frogs that reside within raw water storages and water reclamation plants and compared them to assemblages from nearby natural water bodies over a total of 19 water bodies.Overall, the faunal assemblages within the man-made water bodies showed similarities to the nearby natural water bodies with very few differences found among the three water body types. Diversity of available substrates and of submerged and emergent macrophytes were the habitat variables best correlated with diverse faunal assemblages. This study suggests that the faunal assemblages within raw water storages and water reclamation plants resemble those found within nearby natural water bodies and that there is therefore potential for water-resource infrastructure to act as an important refuge habitat during drought. Furthermore, small changes in the management of these storages to maximise habitat diversity could increase the value of the refuge, complementing their role in water-resource delivery.