Drought refuge

A drought refuge is a site that provides permanent fresh water or moist conditions for plants and animals, acting as a refuge habitat when surrounding areas are affected by drought and allowing ecosystems and core species populations to survive until the drought breaks. Drought refuges are important for conserving ecosystems in places where the effects of climatic variability are exacerbated by human activities.

Description

Reliable drought refuges are characterised by the ability to retain sufficient water throughout the drought, having water quality good enough to maintain the life of the ecosystem, that are not subject to physical disturbance, and that have access to surrounding habitat so that refugees can recolonise the main habitat when the drought ends.

For fish and aquatic invertebrates a drought refuge may be an isolated permanent pool in a stream which ceases to flow and mostly dries up during a period of drought. Permanent wetlands may serve as non-breeding drought refuges for a range of waterbirds that nest at ephemeral lakes when inundated.

Threats and conservation

Because drought refuges may provide the only sites allowing populations to persist during droughts, they are highly vulnerable to factors that affect water quality such as water pollution and sedimentation from anthropogenic runoff. Consequently, in areas subject to intermittent drought, habitat conservation requires the identification and protection of drought refuges.

Conversely, where management of pest species is necessary, controlling them in their drought refuges during droughts may be more cost-effective than broad-scale control at other times. One example of this is controlling rabbits in arid and semi-arid regions of Australia.