The built environment is so much more than concrete and steel. Urban areas are populated not only by humans and industry, but also many plant and animal species that have adapted to our cities across all ranges of environments throughout history. Over time, these species have naturally evolved to better fit the changing environments in which they live. Some birds, for example, have larger brain sizes compared to those of their wild brethren and some urban mammals produce larger litters to counter elevated infant mortality rates in cities.

A 2014 study on the biodiversity of urban animals found that approximately 20% of an area’s native birds and 5% of its native plants can be found in its cities. These creatures primarily rely on urban greenspaces, however small, for their survival. As our modern cities are rapidly expanding on a global scale, with an estimated urban population by 2045 of 6 billion, or 7 in 10 people, the importance of supporting native species and adding to urban greenspace is urgent.

Biodiversity, Environmental Justice and the Heat Island Effect

In recognizing the urgency of climate resilience, it’s also crucial to acknowledge the fact that many lower-income neighborhoods tend to have far less urban tree cover from historic lack of investment. As a result, more efforts to reforest and rewild urban streetscapes are being made in today’s cities, thus leading us in the right direction. The urban tree canopy (UTC) has been shown to significantly reduce “urban heat island effect,” and contribute to healthier environments, stormwater management, evaporative cooling, carbon capture and much more. Non-profit urban forestry programs like City Forest Credits are incentivizing action through carbon credits to support ESG goals. In some environmental justice communities, like parts of Somerville, MA, a grass-roots effort, “Green & Open,” is working to remove backyard asphalt and concrete and replace it with rain-absorbing earth and plantings.

The Inflation Reduction Act has also sought to address this issue by investing funds in the planting of trees in historically red-lined, low-income areas, which will not only generally benefit resident’s health and well-being, but could also increase property values and reduce crime. The US Forest Service has funded almost $1 billion in this program, funding projects in all 50 states, and all will benefit disadvantaged communities. Urban heat island effect is expected to increase in severity with climate change and increased urbanization globally, so it is vital that we reduce the effect through mindful and meaningful design measures as well.

What Designers Can Do

Designers create environments, both outside and inside. We collaborate with landscape architects, civil engineers, and stakeholders to bring native biodiversity into our urban projects. When working with clients, we often discuss target goals, and incorporation of native species to the landscaping can be included in that list. Understanding how a building interacts with the surrounding landscape is a tenet of good urban design, and inviting landscapes can make the difference between welcoming and hostile urban spaces. The LEED metric and the International Living Future Institute (ILFI)’s “Place” petal have also greatly helped out with these efforts by guiding and encouraging building owners to consider the value of Sustainable Sites and local habitat, as well as track the incorporation of native species. The following steps and initiatives can be taken to foster biodiversity in a building project.

• Incorporate site plantings, especially trees, as much as possible. This may be the single largest impact tool that we have, as they provide both shade and evaporative cooling.
• Choose light-colored surfaces over dark surfaces for areas such as roofs and pavements.
• Reduce asphalt parking, replace existing asphalt parking with permeable surfaces and incorporate greenspace as much as possible.
• Incorporate water, where it is plentiful, to help with passive evaporative cooling.
• Consider green roofs and incorporate plants on facades and streetscapes.
• Careful use of highly reflective materials that can magnify the sun & heat.

It Starts Small

Beyond measures that architects and designers take to improve urban ecology, individuals can help improve biodiversity in a variety of manageable ways. Every individual has the ability to help improve local biodiversity – If you have a place to plant or put a potted plant, you can help affect change.