Climates are changing in wetland ecosystems around the world. A research collaboration between the US Geological Survey and Clayton State University examines the impact of historical land use on these important environments and proposes the use of freshwater delivery techniques developed for wetlands in land to help manage coastal systems.
In a recently published paper, the research team highlighted the impact of human land use over time, specifically focusing on the delivery of water to wetlands. Researchers are investigating how wetlands restoration techniques can be used to reduce salinification in coastal wetlands by increasing the delivery of freshwater to targeted regions.
The paper was published on June 9 at Ecosystem Health and Sustainability.
“Land use and climate change are influencing wetland ecosystems, especially in coastal areas where salinification is complicating the problem,” said Beth A. Middleton of the US Geological Survey, Wetland and Aquatic Research Center. “While remediation methods are often better known in inland settings, the solution to coastal wetlands may be similar, especially if the flow of fresh water from inland rivers to the coast is altered.”
As sea levels rise and storms become stronger and more frequent, coastal wetlands absorb more saltwater through surface water and groundwater sources.
However, the climate change link between sea level rise and increased hurricane activity is only one part of the coastal salinification story. Coastal wetlands will also experience an increase in salinity levels due to reduced inflow of fresh water from land sources due to drainage canals and water pumping for agriculture and development; geofluid extraction can also cause the ground to gradually cave-a phenomenon called subsidence.
Eventually, salinification of coastal wetlands can wipe out tree species by reducing sap flow and production, resulting in “ghost forests.” The death of trees can precede the collapse of peat.
Salinification from damaged coastal aquifers is not an easy solution to the problem, according to Jere Boudell from Clayton State University.
“Clearly, in this case, the contributors to the salinification of these wetlands include climate change and land use,” Boudell said. “As the climate warms, increased use of groundwater and surface water by humans will reduce the fresh water available to natural soils and may lead to the extinction of key species.”
Restoring freshwater delivery to wetlands may benefit the conservation of inland and coastal wetlands in the face of climate change.
Techniques used primarily to deliver freshwater flow to inland plains may reduce salinification in some coastal wetlands. While local efforts are being made to rewet floodplains drained by hydrologic disconnection, there is often little systematic monitoring of the results—for example, agricultural floodplains with down-cut channels are rewetted. again by creating obstructions in the channel with objects such as logs or rocks.
Previous studies have shown that plants stressed by drought, water abstraction, or salinification can be supported by the release of fresh water and occasional high rainfall events such as hurricanes, which can sustain the foundation species and ecosystem functions.
When freshwater availability is limited by reduced precipitation and snowpack, or diversion of water for municipal and agricultural use, alternative water sources can be used, according to the paper. For example, declining base flows are supplemented by treated effluent, stormwater, and irrigation runoff. The discharge does not mimic natural flow regimes due to flood risk concerns, but channels at the base of the stream are created or augmented.
“Water quality and the level of wastewater treatment must be discussed to ensure public safety and the environment for these measures,” said Boudell. “However, as these project results illustrate, alternative water sources can potentially sustain and restore riparian ecosystems in water-stressed regions, especially in urban settings.”
Repairing past coastal land use damage to reduce salinity heat can help freshwater species maximize their resilience, growth, and peat-making potential. These methods can help wetlands improve their function and resilience in the face of climate change.
Future research could explore how to deliver enough fresh water to support coastal wetlands while balancing human demand for fresh water.
“Ultimately, we intend to help managers to consider the possibility of solving coastal salinification problems through freshwater management,” said Middleton.
Beth A. Middleton et al, Salinification of Coastal Wetlands and Freshwater Management to Support Resilience, Ecosystem Health and Sustainability (2023). DOI: 10.34133/ehs.0083
Provided by Ecosystem Health and Sustainability
Citation: Freshwater management techniques could benefit coastal and coastal wetlands stressed by climate change (2023, July 18) retrieved on July 19, 2023 from https:/ /phys.org/news/2023-07-freshwater-techniques-benefit-inland-coastal. html
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