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Why do Urban Ecosystems matter?

Philadelphia Urban Ecology

You might already know that we rely on the Earth’s ecosystems every day to supply us with clean air, water, food, medicine, climate regulation, recreation, and more. There’s no doubt that preserving pristine natural areas like National Parks is imperative. But why does LandHealth Institute protect and restore ecosystems in Philadelphia? It might be difficult to imagine the value of protecting the small patches of habitat that decorate urban neighborhoods.

These small patches of urban habitat are not as isolated as they seem. We can envision all of the trees across the city as an urban forest: working together to support one big ecosystem. Urban animals like birds and foxes travel from patch to patch. Of course, the city is also different from a traditional forest. Pavement covers much of the ground, while remaining soil and vegetation is highly altered by human activity. Despite all of the stressors that humans introduce to our urban forest, this novel system continues to thrive in its own way.

When ecologists talk about all of the ways that humans benefit from the ecosystem, we use the term “ecosystem services”. Some common examples of ecosystem services are the pollination of crops, the decomposition of waste, and the cycling of nutrients. Surprisingly, urban habitats provide several additional services that we benefit from every day. For example; urban parks, wetlands, street trees, and even vacant lots reduce the high levels of air and water pollution that occur in urban areas. One study conducted by the US forest service found that Philadelphia's urban forest removes 99,000 tons of carbon dioxide from the atmosphere each year, and removes 513 tons of air pollution each year[1].

Green spaces are crucial for flood control and rainwater drainage as well, which are pressing problems in Philadelphia. Green spaces also keep the city cooler in the summer and can even assist with noise reduction. The US forest service found that Philadelphia’s urban forest reduces residential energy costs by about $6.9 million per year. Dozens of studies have additionally demonstrated that urban green spaces reduce stress levels and improve mental health. Landscaped green spaces have even been shown to reduce crime rates and encourage physical activity.

As we restore urban habitat across the city, more of these benefits will emerge. This is why LandHealth Institute is dedicated to restoring and preserving urban ecosystems. While our objective is to preserve urban biodiversity, our driving force is to enhance the health and happiness of Philadelphian communities. The world is only becoming more urbanized while we all continue to rely on nature for our daily needs. Working with communities to build a healthy and sustainable Philadelphia is urgent - and the first step is understanding our unique urban ecosystem.

[1] Nowak, David J.; Bodine, Allison R.; Hoehn III, Robert E.; Ellis, Alexis; Low, Sarah C.; Roman, Lara A.; Henning, Jason G.; Stephan, Emily; Taggert, Tom; Endreny, Ted. 2016. The urban forests of Philadelphia. Resource Bulletin NRS-106. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 80 p.

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