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Why are wetlands sometimes called the kidneys of the landscape?

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Bald cypress trees with wide, flared trunks stand in still, shallow water in a Louisiana swamp, their green foliage creating a dense canopy. — Wetland Stately bald cypresses (*Taxodium distichum*) thriving in a Louisiana swamp.

Wetlands are often referred to as the "kidneys of the landscape" because of their vital role in filtering and purifying water within an ecosystem. Much like the biological function of kidneys, wetlands act as natural systems that collect, store, and cleanse polluted waters.1

This filtration process occurs as wetlands serve as sinks for inorganic nutrients and organic materials, effectively removing contaminants from the water as it moves through the system. Beyond water purification, this metaphor highlights their capacity to regulate water flow; they absorb large amounts of water, which helps mitigate flooding, protects shorelines, and facilitates the recharge of groundwater aquifers.1

Given their essential role in maintaining environmental health and water quality, the conservation and restoration of these areas are critical for sustainable development and combating water scarcity.1