Discovery Science: Earth – Freshwater Wetlands

Earth Science: Freshwater Wetlands

Wetlands can be found in many different climates. They make up about 6 percent of land areas and provide habitats for numerous animal and plant species. However, they are under increasing threat of destruction.

Freshwater wetlands form an interwoven network of lakes, streams, and rivers. They make a substantial contribution to ground-water replenishment and they influence the regional climate by creating humidity during drought conditions.

Riverine meadowland and fresh-water deltas

The largest continuous wetlands on the mainland are the river meadows with their amphibious landscapes. A diverse ecosystem develops, with calm dead water arms and moving water surfaces, dry gravel and rubble areas, extensive reed fields, and impenetrable floodplain forests. These ecosystems are the habitat for rare animal and plant species.

Many of these species are endangered because rivers have been straightened, dammed, or forced into concrete streambeds, and the fertile floodplains are being utilized for agricultural purposes or as grazing land. Along some of larger rivers, such as the Ohio, Huang, He, or Danube, only relics of the former river meadows remain.

The giant floodplain at the upper Rio, Paraguay, is the home of the rare hyacinth macaw and the jaguar, and a refuge for the threatened giant river otter and the capybara. The Okavango Delta on the northern edge of the Kalahari Desert is the world’s largest inland delta. This delta attracts migratory birds and animals such as elephants, rhinoceroses, giraffes, zebras, antelopes, lions, hyenas, and leopards.


Low moors usually develop through the transformation of nutrient-rich waters into land. The existence of these moors is not dependent on precipitation since there is a connection to groundwater. They can be recognized by the presence of plants such as reeds, willows, alders, and sedge. In contrast high moors are nutrient-deficient areas that rely on precipitation.

The low pH and oxygen deficiency prevent the breakdown of dead plant matter and promote the formation of peat. Plants adapted to these conditions include cotton grass, heather, sphagnum moss, and the flesh-eating sundew. Animals include dragonflies, butterflies, and several rare bird species, such as snipe and black grouse.


RAMSAR CONVENTION In 1971, delegates from 18 nations signed the Convention on Wetlands of International Importance in Ramsar, Iran. This makes it one of the oldest international agreements for environmental protection.

Since the enactment of this convention in 1975, 1670 protected areas with more than 932,056 miles 2 (1.5 million km 2) have been identified in 155 countries.