Freshwater Biodiversity At The Species Level

Source: Food and Agriculture Organization of the United Nations, 2013, David Coates and Jacquie Grekin, CBD,   "The Youth Guide to Biodiversity" 1st Edition (Chapter 7) Youth and United Nations Global Alliance. Reproduced with permission.

Chapter 7. Verbatim.

The Hippopotamus

The hippopotamus is considered to be a freshwater mammal because, although it feeds on land, like a cow, it is adapted to life in water.

For example, it has a flat head on which the eyes and nostrils protrude, enabling it to remain submerged, but still able to see and breathe; a cow could not do this.

River Dolphins: Species in Danger

Although often regarded as marine (saltwater) species, some dolphins live exclusively in freshwater rivers and lakes; others have adapted to live in both marine and freshwater environments. River dolphins differ from oceanic dolphins in several ways, including having a much longer snout – up to 20 percent of their body length – and extremely poor eyesight. Most are comparable in size (about 2.5 m) to the more  common and better-known bottlenose dolphin, a marine species seen in aquariums and featured in movies and on television.

There are six species of river dolphins:

:: Ganges River dolphin (Bangladesh, India, Nepal, Pakistan) – the “Susu” 

::  Indus River dolphin (Pakistan) 

:: Amazon River dolphin (South America) – the “Boto” 

:: Yangtze River dolphin (China) – the “Baiji”

:: Irrawaddy and Mekong River dolphin (salt- and freshwater – Myanmar, Laos and Cambodia) 

:: Tucuxi (salt- and freshwater – east coast of Central and South America).

The Yangtze River dolphin has been presumed extinctsince 2006; the others (with the possible exception of the Amazon River dolphin and the Tucuxi, about which little data are available) are highly endangered. By comparison, the bottlenose dolphin is relatively abundant, and is not in danger of extinction.

The survival of river dolphins is threatened by habitat loss and degradation, as a result of dam construction and river diversion, which reduces waterflow; pollution from industry and agriculture; overfishing; and accidental capture in fishing lines and nets (known as bycatch).

Rice Paddies: Farmed Wetlands

Rice is a wetland-dependant (freshwater) plant and the staple food for over half the world’s population. Itprovides about 20 percent of the total calorie supply in the world and is grown in at least 114 countries worldwide, particularly in Asia.

Rice paddies are naturally flooded or irrigated fields in which rice is grown. Rice grows with its roots submerged, but with its leaves and seeds (rice) above the water. Rice paddies usually dry out at harvest time, illustrating that these systems shift between aquatic and terrestrial (dry land) phases.

Rice is just one crop. But living in the water in the paddy fields are thousands of species of aquatic organisms. Rural populations benefit directly from some of this biodiversity by harvesting reptiles, amphibians, fish, crustaceans, insects and molluscs for household consumption. But other biodiversity associated with rice paddies supports the health and productivity of the rice itself through, for example, controlling rice pests and helping to make nutrients available to the rice plants.

These wetlands also support the conservation of internationally important populations of resident and migratory waterbirds.