Remote Sensing of Wetlands
Remote sensing offers powerful tools for locating and studying wetlands. Synthetic aperture radar (SAR), used to create most of the data products available on this site, is particularly effective for measuring moisture inundation, seasonal variations in water levels or habitat, large-scale vegetation patterns, and effects of natural or human disturbance. SAR bounces a microwave radar signal off the surface of Earth to detect physical properties. Unlike optical technology, SAR can see through darkness, clouds, and rain.
SAR complements other types of remote sensing, enabling scientists to confirm and add to findings about these complex ecosystems. Other kinds of sensors range from cameras carried by satellites, to microphones placed near wildlife habitat, to thermometers moored in streams. Examples of wetlands research results using these other types of remote sensing include identification of invasive plants through airborne photography and videography, detection of pollution from temperature changes in waterways near industrial areas, and detection of red tides by instruments moored underwater that measure pigments in algae.
What Are Wetlands?
Wetlands are ecologically dynamic land areas that support more biological diversity than any other type of ecosystem on the planet. Drenched by varying degrees of moisture for part or all of the year, wetlands can be freshwater, brackish or saline, inland or coastal, seasonal or permanent, natural or man-made. They support a wide range of wildlife and aquatic plants.
Scientists have identified four main types of wetlands:
Why Wetlands Are Important
In addition to supporting an astonishing variety of plants and animals, wetlands filter and purify water, control flooding, and stabilize shorelines. They also are sensitive to changes in climate and can themselves affect climate. That’s because wetlands can either function as carbon sinks or release carbon in the greenhouse gases carbon dioxide and methane, playing an important role in the global carbon cycle and in regulating global climate.
How Wetlands Are Being Threatened
As sources of fish, fuel, and water—and as targets for drainage and development—wetlands are under siege around the world. The ever-growing demand for wetland resources, combined with the effects of climate change, is accelerating the deterioration and loss of these vital ecosystems. Environmental degradation is more prominent within wetland systems than any other ecosystem on Earth, according to the United Nations Millennium Ecosystem Assessment.