Despite the vast amount of water flooding the surface of our planet, a surprisingly tiny amount is salt-free. Only around 3% of the water on Earth exists as fresh water; the bulk of this is ice, but the rest forms a wide variety of amazing freshwater habitats – from babbling brooks to tumbling alpine streams and mile-wide, meandering rivers and from vast lakes to sprawling floodplains and other wetland habitats.
Freshwater bodies can be running or still and either permanent or temporary habitats (such as those that are seasonal). Some shun the limelight and flow through pitch-dark caverns or exist as underground aquifers, while others course magnificently across our planet, creating breathtaking natural wonders such as crashing waterfalls and lake systems so immense that they are visible from space.
Freshwater habitats teem with life, from the familiar to the exotic, and from common to critically endangered species: iridescent damselflies and Irrawaddy dolphins; axolotls and Amazonian manatees; spoonbills and shoebills; American alligators and Siamese crocodiles; hippos and hellbenders; great crested newts and goliath frogs; giant otters and giant crayfish; electric eels and Baikal seals.
Without freshwater ecosystems, life on Earth as we know it would not be possible. Yet, without their rich biodiversity these ecosystems would quickly collapse and cease to function, as it is this diversity that keeps freshwater systems clean and healthy.
Freshwater ecosystems cover a mere 0.8% of our planet’s surface, yet they harbour more than 10% of all known animal species.
or so of the world’s fresh water is locked up within glaciers and ice caps.
people worldwide are estimated to depend on freshwater biodiversity for food.
Fresh water harbours and sustains myriad animal and plant species from platypus to papyrus, but no species depends on this resource as heavily as humans. We use it for everything from drinking, cooking, fishing and crop irrigation to transportation, energy production and waste disposal.
Sadly this means that we have had a profound effect on the health of freshwater systems, with the result that a great many freshwater habitats have been severely degraded and even destroyed in recent history.
Perhaps the most dramatic and tragic case was that of the Aral Sea in Central Asia – once the fourth-largest freshwater lake in the world – which has now all but been destroyed by an ill-conceived 1960s project that aimed to convert deserts into farmland for cotton and other thirsty crops. The two major rivers feeding the Aral were diverted for irrigation and the lake dried up, with devastating consequences for wildlife and local livelihoods. Shocking images from NASA show the decline.
All around the world, humankind’s efforts to bend freshwater ecosystems to our will have produced a litany of environmental problems, from drained wetlands and aquifers to dammed rivers that impede migratory species and disrupt natural river flow, to flood prevention measures that degrade wetland habitats and silt up riverbeds and coastal habitats. The list goes on.
Our activities on land also affect freshwater systems. Deforestation of upstream watersheds can cause severe flooding downstream during heavy rains as well as sedimentation that can choke aquatic and coastal habitats. Industrial pollution can poison freshwater wildlife, while agricultural run-off and sewage effluent can upset the nutrient balance of freshwater habitats causing algal blooms that deplete oxygen and create dead zones.
Like all ecosystems, freshwater environments are carefully balanced. Upset this balance and the system can quickly unravel. They may be just a drop compared to the ocean, but given how heavily we depend on these resources – and simply because they are wonderful– we need to take much greater care of our planet’s fresh water as well of the many species and connected ecosystems that keep it flowing clear and pure.
Fauna & Flora International (FFI) has a strong track record in protecting wetlands, forest watersheds and other species-rich freshwater habitats. Recent examples of our work include:
Protecting vital habitats
What does the rainforest smell like? What’s going on beneath the ocean waves? What is so remarkable about a dark, damp cave? Read on to explore the fascinating environments where we work.
We live on a blue planet. About 71% of the Earth’s surface is covered in water, and a whopping 97% of this is found in our seas and oceans. Yet there is much still to discover about this watery realm.