Greener, healthier, more sustainable: why cities of the future need more biodiversity.

Modern science has proven environmental factors heavily influence human health - which is why each and every one of us would benefit from an intact ecosphere with good quality air, water and produce. In fact, by changing the conditions in which we live, we might be able to improve our health and reduce costs for healthcare systems.

And since biodiversity is a reasonable indicator of the overall health of an ecosystem, we should try to optimize it. In consequence we might improve the health of the inhabitants and liveability of urban environments.

Ecologists bemoan the fact that urban environments are often left out of biodiversity studies - and that urban environments lack true biodiversity, period, due to the lack of spaces undisturbed by humans, the lack of corridors between green patches and the overall level of pollution.

How can cities of the future transform themselves to be more sustainable, healthier and biodiverse? Here are a few ideas.

A proposal for tomorrow's cities

The goal of cities of the future should be to create a variety of undisturbed land-based and aquatic biotopes within urban environments, connected by corridors for animals to migrate and for seeds to spread. Green roofs, conventional parks, private gardens and green facades could create additional space for animals and plants to thrive.

Toronto is one example of a city that adapted development regulations according to this model, by passing the Green Roof Bylaw, which requires a certain ratio of green roofing for new developments above a certain size.

Toronto also offers subsidies for building owners willing to create green roofs with their Eco-Roof Incentive Program, something other cities should mimic; and some already do. While not all municipalities can create a costly incentive program like Toronto, they could, for example, reduce the mowing of public grasslands, sidewalks and other areas, which would improve living conditions for bees and other species. An even eco-friendlier policy might be to use animals for grazing these grasslands, providing natural fertilization and means of local food production. In Munich, one of Germany's largest cities, a flock of sheep is using Englischer Garten, one of the largest urban public parks, as pasture, which could be model for other public parks.

Sheep graze in Englischer Garten in Munich to provide natural fertilization.

Municipalities could also declare a certain part of their forests as protected areas or plant...