What ecosystems give us, and what we owe them

People benefit from ecosystems too. Forests give fresh air, fertile soil, food, fibres, timber and medicines. Aquatic ecosystems give water and food. Ecosystems are also beautiful and good places to relax. All this supports our well-being, and when we overuse or misuse natural resources, we disturb nature's balance.

Take a real ecosystem: the Sundarbans, the largest mangrove forests in the world, where the Ganges and Brahmaputra meet between India and Bangladesh. Its forests and rivers are home to many plants and animals, many of them endangered. The Sundarbans protect people by slowing strong winds and waves in storms and floods, and its trees absorb carbon dioxide and release oxygen. UNESCO declared it a World Heritage Site in 1987.

It is under serious threat: mangroves are cut for fuelwood and farming, illegal hunting and overuse threaten the wildlife, and industrial waste and untreated sewage pollute the water. Other Indian ecosystems face cutting of forests, overuse, invasive species, poor land use and pollution. Protected areas are land or water set aside to conserve wildlife and habitats: national parks, wildlife sanctuaries, biosphere reserves and community conserved areas. Examples include Jim Corbett (Uttarakhand), Manas (Assam), the Nilgiri Biosphere Reserve, Chilika Lake (Odisha), Eaglenest (Arunachal Pradesh), Hemis (Leh), Keibul Lamjao (Manipur) and Pirotan Island Marine National Park (Gujarat).

People also build artificial ecosystems (fish ponds, farms and parks) to meet their needs. Well designed, they can cut pollution, support biodiversity and give people places to relax. But unlike natural ecosystems, which run themselves, they need human care and management.

Farming is a major livelihood in India, and it can become unsustainable if it isn't managed well. Between 1950 and 1965 India faced a food crisis because crops were poor. Then, in the mid-20th century, tractors, machines, synthetic fertilisers and pesticides raised food production hugely: the Green Revolution.

Those methods are now seen as unsustainable, because of overuse of synthetic chemicals, pumping out too much groundwater, and growing just one crop for profit. Too much synthetic fertiliser can lower soil fertility, by killing friendly microorganisms and reducing the humus (organic matter) that binds soil particles; without enough humus, soil erodes easily. It also kills natural predators, so pests increase. Heavy watering and repeated ploughing disturb soil creatures such as earthworms and snails.

Some pests become resistant to pesticides and get harder to control. Growing the same crop again and again, monoculture, reduces biodiversity and hurts pollinators, which food production depends on. To farm sustainably, some farmers are trying organic and natural methods that use fewer synthetic fertilisers and disturb natural ecosystems as little as possible. The ancient text Vrikshayurveda said the same long ago: keep feeding the soil with organic manure such as Kunapa Jala, a liquid fertiliser fermented from animal and plant waste, and other compost. Save nature, and nature saves you.