Ephemeral wetlands are areas that temporarily hold water, typically in the spring and early summer, or after heavy rains. These areas then dry up for a period during the year. Many animals, such as mammals, birds, amphibians, reptiles, and insects rely on ephemeral wetlands, as well as on the surrounding upland habitat. Ephemeral wetlands are of particular importance for amphibian populations, which are in decline globally.
Ephemeral wetland swamp in British Columbia. Credit: Doug Biffard
These sensitive habitats are threatened by human disturbance. Roads and buildings create barriers and hazards to migration for wildlife, and potentially change the hydrology of the surrounding area. Climate change also threatens wetlands by changing precipitation patterns. To protect amphibians and other wetland wildlife and help them deal with challenges like disturbance and climate change, management should recognize wetlands and surrounding upland habitats as “patches” to be preserved.
In addition to preserving individual wetlands, it is also vital to preserve a network of wetlands and uplands that allows species to move between patches. This management strategy recognizes wetlands and ephemeral wetlands as a network, and acknowledges the meta-population dynamics where both patches, and connections between patches, are important for species in an area. Ephemeral wetlands may play an important role for meta-populations by temporarily increasing connectivity between wetland and upland terrestrial habitats. In other words, ephemeral wetlands can serve as “stepping stones” for amphibians and other animals as they move between habitats.
The endangered western tiger salamander (Ambystoma mavortium). Credit: Daiju Azuma.
A new study looked at one endangered species, the western tiger salamander (Ambystoma mavortium), and modeled the role of ephemeral wetlands for their movement and persistence during wet, dry, and typical years. They found ephemeral wetlands to be critical for amphibian movement between wetlands during wet years. During dry years, connectivity across wetlands decreased and breeding pools for the endangered species shrank; then, sporadic wet years created ephemeral wetlands, allowing movement across the meta-population and increasing population viability.
Their findings highlight the importance of preserving these ecosystems, particularly in the face of climate change and more variable precipitation patterns. In addition, they recommend management expand beyond thinking of wetlands only as patches, and instead consider the broader landscape context. This ensures that ephemeral wetlands continue support high levels of biodiversity into the future.
Resources:
Allen, C., Gonzales, R. and Parrott, L. 2020. Modelling the contribution of ephemeral wetlands to landscape connectivity. Ecological Modelling 419: 108944.
