It's a phrase that's been on the lips of scientists, officials and environmental activists a lot in the last few months: ecosystem restoration. This year, 5 June, World Environment Day, marks the official launch of the UN Decade on Ecosystem Restoration, a 10-year push to halt and reverse the decline of the natural world.
You might be wondering: what exactly is an ecosystem and how do you restore one?
To answer the first question an ecosystem is a place where plants, animals and other organisms, in conjunction with the landscape around them, come together to form the web of life.
Ecosystems can be large, like a forest, or small, like a pond. Many are crucial to human societies, providing people with water, food, building materials and a host of other essentials. They also provide planet-wide benefits like climate protection and biodiversity conservation.
But in recent decades, humanity's hunger for resources has pushed many ecosystems to the breaking point.
Here are the eight main types of ecosystem and some of the things that can be done to revive them. For more ideas on how to boost your local ecosystems and join #GenerationRestoration, see the UN Decade's Eosystem Restoration Playbook - a practical guide to restoring the planet.
Over-intensive use, soil erosion, excess fertilizer and pesticides are exhausting many farmlands. Ways to restore them include reducing tillage, using more natural fertilizer and pest control, and growing more diverse crops, including trees. These steps can rebuild carbon stores in soils, making them more fertile so countries can feed their growing populations without using even more land. The restoration of farmland also creates habitats for wildlife.
Did you know? Nitrogen from fertilizers used in industrial agriculture not only pollutes air and water, it also helps drive climate change.
Forests and trees are being cleared to feed humanity's hunger for land and resources. Logging, firewood cutting, pollution, invasive pests and wildfires are damaging what remains. Restoring forest ecosystems means replanting and reducing the pressure on forests so that trees re-grow naturally. Food systems are a major driver of forest loss. Reconsidering the way people grow and consume food can help reduce the pressure on forests. Degraded and disused farmland can be ideal for forest restoration, which can also mean nurturing patches of forest and woodland in landscapes that include busy farms and villages.
Did you know? Forests provide a habitat for 80 per cent of the world's amphibian species as well as most birds and mammals.
Lakes and rivers
Safe and abundant water has become a luxury. Freshwater ecosystems have been degraded by pollution, overfishing and infrastructure as well as the extraction of more and more water for irrigation, industry and homes. Restoration means halting pollution, reducing and treating waste, managing demand for water and fish, and reviving vegetation above and below the surface.
Did you know? Many fish eat insects, so humanity can restore rivers by letting more insect-friendly plants grow on their banks.
Grasslands and savannahs
Shrublands, grasslands and savannahs are being overgrazed and eroded, converted to agriculture and invaded by alien species. Humans can help them rebound by clearing woody vegetation and re-seeding native grasses. Lost plants and animals can be re-introduced and protected until they are established. Pastoralists and other users must have a big part in plans to manage these ecosystems sustainably.
Did you know? Grasslands and savannahs are where humans evolved millions of years ago.
In mountain regions, clearing slopes for farming or houses can trigger dangerous erosion and pollute rivers at their source. Soaring temperatures are forcing species, ecosystems and people to adapt or move. Humanity can counter the trend by reviving forests and restoring the protection they provide against avalanches, landslides and floods. Officials can plan dams and roads to avoid fragmenting rivers and other habitats. Farming techniques like agroforestry can be more resilient in the face of climate change.
Did you know? At least 600 glaciers have vanished in recent decades, affecting water supplies for billions of people living downstream.
Oceans and coasts
Marine ecosystems are under assault from pollution, climate change and overexploitation. But the solutions are as common as the threats. Governments and communities can make fishing and mangrove harvesting more sustainable. They can properly treat sewage and other waste and stop plastic trash from entering the water. Coral reefs, mangroves and seagrasses must be carefully managed and actively restored so that oceans can continue to support billions of livelihoods globally.
Did you know? Seagrass is a hidden climate champion, capturing carbon up to 35 times faster than tropical rainforest.
Peatlands and their massive stores of carbon and water are being drained and converted for agriculture and degraded by fire, overgrazing, pollution and peat extraction. Avoiding dangerous climate change means holding peatland carbon where it is - wet, and in the ground. At the same time, humanity must re-wet and restore many degraded peatlands - for instance, by closing drainage channels - to halt their emissions and protect rare plants and animals.
Did you know? Peatlands cover only 3 per cent of the world's land but store almost one-third of all the carbon in its soil.
Cities and towns can seem like ecological deserts. There's little room for vegetation amid the houses, roads and factories. Waste and pollution imperil waterways, soils and the air. But urban areas have huge potential for restoration. Citizen groups and municipal authorities can clean up waterways, let bee-friendly plants grow and create urban woodland and other wildlife habitats in parks, schools and other public spaces. Mowing grass less frequently is cheaper for cities and allows nature to thrive. Permeable sidewalks and urban wetlands protect against flooding and pollution. Contaminated industrial areas can be rehabilitated and turned into places for nature and recreation.
Did you know? More than 280 species of bird have been recorded in New York City's Central Park.
Led by the United Nations Environment Programme and the Food and Agriculture Organization, the UN Decade will draw together political support, scientific research and financial muscle to massively scale up restoration with the goal of reviving millions of hectares of terrestrial and aquatic ecosystems. Visit www.decadeonrestoration.org to learn more.