Drought refuges are important for conserving ecosystems in places where the effects of climatic variability are exacerbated by human activities.
[2] Permanent wetlands may serve as non-breeding drought refuges for a range of waterbirds that nest at ephemeral lakes when these are inundated.
The term refugium (plural: refugia) was originally used by evolutionary biologists for refuges that protected entire species from disturbance events of large temporal and spatial scales, such as glaciation or the long-term effects of climate change.
[7] Refugia are the habitats or environmental factors that give spatial and temporal resistance and resilience to biotic communities impacted by disturbance.
[10] Lack of precipitation causes drying of aquatic ecosystems and leads to a natural disturbance called a drought.
[9] This links with interactions that structure the communities of different species and affects mortality, birth and migration rates.
[11] Drought refuges protect plant and animal populations from extreme weather events as climate trends evolve .
[16] Drought refuges form habitat mosaics which are prone to increased fragmentation by flow regulation.
[16] The size of a pool influences the set of species, total number of organisms, and assembly structure because of physicochemical factors.
[8][16] While used infrequently and often containing only few individuals during normal years, range edges may episodically serve as refuges from extreme weather events or conditions such as drought.
[12] During these extreme conditions, survival probability, reproductive success or both is higher at the edge than in the core of its range.
[8] Rates of mortality, birth, migration, and interactions among components of the biota that have retreated to refugia are affected by the nature of the refuge.
[7] Refuges for macrophytes and zooplankton typically comprise egg and seed banks in med-rivers and are resilient to prolonged drying.
[7] Drought leads to a shift in refuge spacing and connections at different spatial and temporal scales.
[16][9] Droughts disrupt hydrological connectivity and impact resident species through loss of water and flow from drying, habitat reduction, and reconfiguration.
The drought from 1996 until 2009 had a great impact on the Murray-Darling Basin, in Northern Australia (Murphy and Timbal 2007; Umenhofer et al. 2009).
Drought refuges are likely to sustain biodiversity over larger spatial scales such as groups of streams or whole drainage networks.
[9] Physical organism adaptations include an ability to aestivate, mouth orientation that allows for breathing oxygen at the water surface, body armor, and venomous spines.
[8] Mobile species' coping methods include refuge-seeking behavior; they seek habitat patches that relieve physiological stress and reduce mortality.
[15] Reliance on dispersal improves resilience to climate change in the short term, but over longer timescales, it will not protect macro invertebrate biodiversity from landscape-scale refuge degradation.
The hyporheic zone, a region along streambeds where groundwater mixes with surface water,[14] is an important refuge for immobile organisms, like algae.
Perennial waters, whether pools, seeps or flowing sections of streams, have repeatedly been shown to be the major refuges.
[15] The capacity for perennial refuges to support biodiversity may be severely compromised due to increasing water temperatures, reducing the quality of refuges by exceeding the thermal tolerance of invertebrates or by causing anoxia in stream pools and existing environmental degradation of many perennial water-ways.
Water conservation is done in order to migrating bird populations (National Wildlife Refuge; March, 1, 2016).
[10]Pollution and over-extraction of groundwater are both problematic because it lowers its ability to support groundwater-supplied drought refuges.
[10] Over-extraction often occurs in areas with surface water scarcity and frequent drought; where groundwater refuges and refugia are most important.
Forests undergo decline in areas of high salinity and shallow groundwater depths because these conditions make them more susceptible to droughts.
Forests undergo decline in areas of high salinity and shallow groundwater depths making them more susceptible to droughts.
[10] Knowledge of refuge functions is critical for understanding their role in conservation of biodiversity, especially climatically sensitive species.
[7] There is increasing evidence that habitats created by humans, such as canals, ditches, and farm ponds can support freshwater biodiversity and, therefore, have potential to provide refuges.