Food security

What is urban ecology and why is it important?

In the summer of 2007, humanity reached a milestone. For the first time in human history, more people were living in cities than in rural areas. Those people need food, clean water and air, and other necessities of modern living.

At the turn of the 20th century, with more people living in cities, residents lived further from food production sources. This put a burden on the agricultural land for food production, and meant an increase in transportation costs. Additionally, handling fresh food became a new industry within our urban culture.

Many people on a city street corner, walking in many directions; lots of signs showing
In 2007, humanity reached a turning point. More people live in cities than in rural areas. 📸: Morguefile

Urban ecology provides answers to these and many other questions so that our cities can thrive – without harming the people, plants, and animals living there. This new area of science can also benefit those areas. It can help cities learn to re-use natural resources through recycling of nutrients that are hyper-consolidated in the urban environment.

One of the interesting questions urban ecology wrestles with is urban food production and the impact it has on cities and human health. A well-known ecological principle that pertains to diversity is that the more species diversity you have in a system, the healthier that system is. It’s also more resilient. For example, the Irish Potato Blight occurred mostly because farmers were only growing one type of potato. This made those potatoes – and the entire crop – more susceptible to any insect or microbial attacks. (For more on that, read this blog.) As a result millions of people were displaced from their homes and their heritage.

Invasive species also create similar problems to those the potato farmers encountered. The emerald ash borer which is native to Asia is one such story. The small green beetle has come to America. This beetle has few natural predators in the United States. Thus it has started to destroy our native Ash trees. Currently 15% of Colorado’s urban forests are Ash, and there are 1.45 million ash trees alone just within the city of Denver. That meant that when the Emerald Ash Borer migrated to the area, there was no natural defense against this invasive insect. Without treatment the trees were killed. It’s definitely a tragedy – but one that we can definitely learn from. Whether it’s through diversification within cropping systems or the exclusion and management of invasive species, urban ecology provides us with the tools to do better in the future.

Red and green apple on tree
As urban trees die and need replacement, they can be replaced with fruit-bearing trees, such as this apple. Credit: Morguefile

As these ash trees die or get removed, they can be replaced with food producing varieties of different fruit trees: cherry and apple, pear and mulberry. Not only are these food producing trees beautiful when they bloom, but they provide pollen to the bees and other pollinators. The Beacon Food Forest of Seattle, Washington produced 4,250 pounds of food in 2017! That’s on just a portion of the proposed seven acres of land the forest will eventually encompass.

Flat tops of city buildings showing green produce growing in rooftop gardens. Street below. Not all roofs have gardens.
This urban farm is on the rooftops of student-oriented apartment buildings in Berkeley, CA. The rooftops are connected by exterior walkways. Up to 16 tons of produce is harvested each year. 📸:

Food forests aren’t the only way to integrate food production into the urban ecosystem. Small garden plots on empty lots and public land can be turned into community gardens. “Green” Roofs can also serve as gardens, and commercial greenhouses make up a thriving urban food production system that few of us hear about. Even your home garden can contribute to food production!

Urban food production might not feed the entire world, but it reduces the total miles driven bringing food to the city. This means less air pollution! It also helps to reduce food insecurity, and makes better use of the water we have transported and cleaned. Urban food provides verdant landscapes which soothes the mind surrounded by a jungle of concrete and steel. Food production impacts the city on many levels. Urban ecology influences how these resource decisions are made and how those decisions impact not only us, but also the plants and animals that inhabit those vibrant communities.

Answered by Ryan Taylor, Colorado State University

This blog is sponsored and written by members of the American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified professionals in the areas of growing our world’s food supply, while protecting our environment. They work at universities, government research facilities, and private businesses across the United States and the world.

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