Although cities occupy just 2 per cent of the Earth’s surface, their inhabitants use 75 per cent of the planet’s natural resources. Cities draw on their surrounding ecosystems for goods and services, and their products and emissions can affect regional and even global ecosystems. Healthy ecosystems and biological diversity are vital for cities to function properly. Ecosystems provide three main kinds of services to the city: provisioning, regulating and enriching. While some of these services are easily measured, such as the provision of food and fresh water, others are harder to quantify, such as the contribution an ecosystem makes to quality of life in aesthetic or spiritual terms.

Biodiversity – the diversity among living organisms – plays an essential role in ensuring the survival of life on earth. Clean water, foodstuffs, medicines and quality of life are just a few of the services which biodiversity offers to cities. Recognizing the importance of biodiversity and healthy ecosystems for their survival, cities today undertake many initiatives to utilize and conserve their surroundings efficiently. These actions can reach far beyond the boundaries of the city, affecting biodiversity on a global scale.