Urban Biodiversity: A Comprehensive Overview
In today's rapidly urbanising world, the preservation and enhancement of urban biodiversity have become essential components of sustainable city living.
Urban biodiversity, as defined by the World Wildlife Fund, encompasses any species that live in or around cities. These include plants, animals, fungi, and microorganisms that have adapted to co-exist in dense human settlements.
Cities, which only occupy around 3% of the Earth's surface, are growing at an accelerating rate. Urban sprawl is expanding by 1.16km every hour, urbanising natural or rural land equivalent to the size of Paris every five days.
Despite this, cities are not merely concrete jungles devoid of life. They are home to a rich tapestry of urban wildlife, from grasslands and urban forests to the unnatural structures humans have built. Urban species have adapted to these environments, with examples ranging from birds nesting on office block facades to insects making their homes in wall cavities.
The preservation of urban biodiversity is not just about providing a space for wildlife to live. It's about creating sanctuaries where species can feed, breed, and thrive, free from the risks posed by human interference, insecticides, and invasive species. Making room for larger predators also serves as a natural population control for smaller animals, including species that can be dangerous to human health, such as mosquitoes and scorpions.
Urban biodiversity plays a crucial role in maintaining ecosystem services. It helps in maintaining air and water quality, climate regulation, and pollination. More than 75% of global food crop types rely on animal pollination, underscoring the importance of urban biodiversity to our food supply.
Biodiversity also contributes to the economy, with the potential to create 59 million green jobs by 2030. Furthermore, research suggests that biodiversity correlates with reduced stress levels and quicker recovery rates among hospital patients.
Cities are not just consumers of regional biodiversity; they also serve as important refuges for an array of plants and animals, in some cases even threatened and endangered species. Urban green spaces, when designed thoughtfully, can be incredibly effective at mitigating flood risks by absorbing stormwater, and in carbon sequestration, with diverse urban grasslands being an incredibly effective carbon sink.
However, not all green spaces are equal in supporting urban biodiversity. Manicured gardens, sports pitches, and playing fields more closely resemble deserts for wildlife. Lush, well-kept lawns may look good when weed-free and tightly mown, but they fall short of what wildlife needs.
City planners are recognising the importance of urban biodiversity and are integrating biodiversity considerations systematically into urban planning. Examples include Bern's systematic integration of biodiversity into urban planning, Berlin's green infrastructure projects like the sponge city elements to improve water retention and habitat quality, and the restoration of natural habitats such as water bodies to increase resilience and biodiversity.
Some cities are even intentionally introducing species to improve urban biodiversity. For instance, Vancouver plants large trees to soak up stormwater, while Leicester increases grassland to act as a carbon sink. Innovative drainage solutions with permeable materials and vegetation are also being used to enhance urban ecosystems and manage rainwater sustainably.
In conclusion, urban biodiversity is a linchpin to how cities function and a cornerstone of the economy. It is essential that we continue to prioritise the preservation and enhancement of urban biodiversity as our cities grow and evolve to accommodate our growing population's needs.
