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SustainabilityScience & Tech

An Ecologist’s Guide to the City

2008 was an important year in human history. It marked the first time that the world’s population was evenly split between people who lived in cities and those who lived in rural areas. After about 2000 years of slowly building civilizations from the ground up, there was now a 50% chance that anyone could be born in a city environment. 

Unfortunately, with the vast expansion of these massive urban areas, many natural environments were engulfed in the process, leaving many species with no choice but to try to survive in a concrete jungle. Some animals thrived in this new environment (about 1 in 10), others were less successful. Those who survived created a new kind of ecosystem that has continued to develop along with the ever-changing urban environment. This ecosystem, despite its many conflicts with human lifestyle, is important to maintain in order to keep our cities environmentally sustainable. 

But why, you may ask? Can’t animals just live in their own space outside of the city? How can two ecosystems exist at once? Shouldn’t I just worry about maintaining my own?

The first problem with this philosophy is that it’s already too late – many animals have essentially become permanent residents in cities (thanks to our food waste). The second problem is that cities need green spaces in order to remain sustainable in terms of atmospheric gases, and to provide places of recreation for mental and physical well-being. Since every animal is a small part of a larger fragile food web that our environment depends on, it is important that we try to appreciate all urban creatures, even if they unknowingly cause damage to our buildings and structures. 

Here are a few of these animals and the roles they play. 

1. Squirrels 

An Ecologist's Guide to the City

Yep, those rodents you likely see running up and down your fence every morning. Though they can sometimes cause damage to the wiring systems of the grid, and set up nests in inconvenient places, squirrels successfully propagate various species of plants around the city, just as they normally would in the wild. Since about 10-20% of nuts buried by squirrels are forgotten, those lost nuts can significantly improve the distribution of plants throughout cities, which helps regulate atmospheric gases like carbon dioxide and oxygen. 

2.  Snakes

An Ecologist's Guide to the City

Though they are less commonly seen in the downtown core area, certain snake species play an important role in cities around the world. As a predator of rodents and insects, they help control the populations of common omnivores, which tend to gather in places where food crops are abundant. For example, in agricultural regions of the city like vegetable gardens, snakes can help mediate rodents and crop pests that attempt to eat away at the plants grown for human consumption. 

3. Insects

An Ecologist's Guide to the City

Insects consist of a vast array of complex species, a number of which have adapted to live in cities. Due to their sheer quantity they are likely the most complained-about type of animal in the urban world. Nevertheless, these tiny creatures are relied upon by most other forms of life. One way they play such a significant role in the biosphere is through food waste management. Insects forage large quantities of food waste on the streets the same way they would in the wild, and research suggests that the amount of food they consume is truly staggering. In one study, it was found that they devour around 2.1 tonnes of waste annually from a median between two roads in North Carolina alone. However, the real benefit insects have towards the environment is their role in plant pollination. Since about 75% of the flora we eat require pollinators, making urban gardens welcoming for pollinating insects (such as bees and butterflies) can improve the yield of food produce. The flowering plants that add aesthetic appeal to our gardens also require pollinators in order to bloom each season. As an additional benefit, having urban green spaces or gardens nearby residential areas that are designed to attract such pollinators could potentially reduce the probability of insect house invasions. 

All this is not to say that animals create the perfect city environment. As we create urban areas, it is important to understand that biological ecosystems may clash with our city networks, our homes, and our industry. However, knowing the lifestyle and ecological importance of city-dwelling animals creates a newfound appreciation for their existence. Even if they cause us economic damage, they help maintain the plants that regulate our air quality, eat bits of our leftover waste, and improve our designated green spaces. For the sake of our mental and physical well-being, we cannot live in a place void of life. Why not embrace what lives beneath our front porch?

Author

An Ecologist's Guide to the City
Ross is a graduate student at Ryerson University studying urban planning.