Human stresses such as agriculture, habitat degradation, and wastewater effluents have a deleterious influence on biodiversity in streams and rivers.
Little is known about the extent to which their ability to self-purify and other important ecosystem functions are similarly compromised.
In a recent meta-analysis published in Global Change Biology, an international research team led by the Helmholtz Centre for Environmental Literature (UFZ) synthesized the internationally accessible research on this issue.
This research proposed new strategies for better water management.
Global effects of Ecological functions of streams and rivers
Streams and rivers are the lifeblood of our world, biodiversity hotspots, and vital to human life: they supply drinking water, flood protection, and irrigation for agricultural areas.
However, people have an influence on freshwaters and their biological functions through behaviors, such as changing the shape of water bodies, agriculture, and wastewater discharge.
Of course, this has a number of negative ecological consequences, according to Dr. Mario Brauns, a scientist at the UFZ Department of River Ecology, as per ScienceDaily.
The majority of research focuses on the consequences of biodiversity, yet this may just be a portion of the problem.
Although biodiversity loss can indicate that freshwaters are being impacted by human pressures, the issue of whether and to what degree their ecological services are being compromised remains unsolved.
Data analysis found that the efficiency with which streams retain nitrates in agricultural catchments is roughly five times lower than in pristine catchments.
Brauns argues that agriculturally influenced rivers and streams have high pollutant concentrations and a deteriorated structure, causing them to no longer fully fulfill their biological role and lose a significant percentage of their purifying service.
Another significant finding is the comparative stressor analysis, which determines which stressors have the largest influence across all ecological functions.
Wastewater comes in first, followed by agriculture and urbanization. According to Brauns, these pressures require immediate attention.
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Stream ecology
Streams are an important aspect of the Earth's circulatory system. They transport sediments, nutrients, and other things from rivers and lakes to the ocean.
Healthy streams help to maintain the health of rivers, lakes, and estuaries., as per the Smithsonian.
However, streams are crucial ecosystems in their own right, giving wildlife habitat, protecting us from flooding, and providing a significant portion of our drinking water.
Streams provide a home for many freshwater species. Diadromous fish, such as salmon, river herring, and American eels, spend part of their life in freshwater and half in the sea.
Many insects, frequently overlooked in the aquatic environment, require stream habitat, particularly larvae.
Aquatic insects play a significant role in stream food webs. They can also function as "canaries in the coal mine" as indicator species.
The diversity of bug species reflects whether or not a stream is healthy. Mayflies and other delicate insects flourish only in calm, unpolluted streams.
When ecologists discover a stream teeming with mayfly larvae, it's a good indicator that the stream is in good health. When mayflies vanish, the stream may be in jeopardy.
But what exactly is a healthy stream? Stream health extends beyond pollution reduction, while this is vital.
Protecting stream banks and channels from erosion is another part of keeping streams healthy. High-energy currents can damage habitat and generate steep, high banks during storms or floods.
Impervious surfaces, such as roads and driveways, can amplify currents by preventing soil from absorbing rainwater before it enters streams.
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