The Importance of Freshwater Biodiversity

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.

Freshwater biodiversity provides a variety of benefits (ecosystem services) to people, including:

Food: in developing countries, inland fisheries can provide the primary source of animal protein for many rural communities (see box: “Aquaculture”). Aquaculture, the farming of fish and other aquatic animals (e.g. shrimp), can also provide food and income for many people, as can wetland agriculture, such as rice farming.

Fibre: throughout human history, many wetland plants have been a source of fibre for making such items as baskets, roofs, paper and rope. Papyrus, for example, was used for making paper as early as 4000 BC (think of the ancient Egyptian scrolls).

Recreational and cultural benefits: many rivers, lakes and wetlands are highly valued for recreational and cultural benefits, some of which have high economic value (such as tourism). In developed countries, sport fishing is also an important recreational activity and a significant source of income for many communities. Recreational fishers have been a major driving force in cleaning up freshwater environments to restore recreational benefits. 

Aquaculture

Recreational and cultural benefits: many rivers, lakes and wetlands are highly valued for recreational and cultural benefits, some of which have high economic value (such as tourism). In developed countries, sport fishing is also an important recreational activity and a significant source of income for many communities. Recreational fishers have been a major driving force in cleaning up freshwater environments to restore recreational benefits.

Aquaculture is the farming of fish and other aquatic animals and plants (e.g. shrimp, frogs, mussels, oysters and seaweed). Freshwater aquaculture can be very beneficial and provide food and income for many people, particularly in rural communities in developing countries.

Aquaculture originated as freshwater carp farming inAsia and is now widespread. Asia still leads the way inthis industry, accounting for 92 percent of global production (70 percent in China, 22 percent in the rest of the region).

Worldwide, about half of production is in fresh or brackish water (a mix of fresh and salt water), and the other half in marine environments. Most aquaculture production in freshwater is fish. The main freshwater species cultured include carp, tilapia, pacu, catfish and trout.

Production from freshwater fish species tends to be more sustainable than from marine species because most of it is based on vegetarian rather than carnivorous species. For example, it can take two kilograms of fish to produce one kilogram of salmon (a carnivorous fish), which doesn’t sound like a good deal. Better to eat lower down the food chain!

Aquaculture can cause water pollution (from chemical use and waste products) and introduce invasive alien species (species that have spread outside of their natural habitat and threaten biodiversity in the new area). Efforts must bemade to address these  impacts, particularly as aquaculture develops, expands and intensifies. 

Carbon storage: climate change is largely due to the release of carbon dioxide and other greenhouse gases into the atmosphere. Wetlands, particularly peatlands, are “carbon sinks”: they remove and store significant quantities of carbon from the atmosphere. Peatlands alone store more than twice as much carbon as all the world’s forests. Destruction of these wetlands results in the release of carbon into the atmosphere, increasing the intensity of global climate change. Human exploitation has destroyed 25 percent of the peatlands on Earth.

Water purification and filtration: plants, animals and bacteria in forests, soils and wetlands also filter and purify water. Wetland plants accumulate excess nutrients (such as phosphorus and nitrogen) and toxic substances (such as heavy metals) in their tissues, removing them from the surrounding water and preventing them from reaching drinking water. They can be thought of as “nature’s kidneys” (see box: “Biodiversity = Clean Water = Human Health”). 

Flood regulation: many wetlands provide a natural flood barrier. Peatlands, wet grasslands and floodplains at the source of streams and rivers act like sponges, absorbing excess rainwater runoff and spring snowmelt, releasing it slowly into rivers and allowing it to be absorbed more slowly into the soil, preventing sudden, damaging floods downstream. Coastal freshwater-dependent wetlands, such as mangroves, saltmarshes, tidal flats, deltas and estuaries, can limit the damaging effects of storm surges and tidal waves by acting as physical barriers that reduce the water’s height and speed. As global climate change raises sea levels and increases extreme weather in many parts of the world, the need for theseservices has never been greater.