Urbanization: The Killer of Diversity

Anonymous

High School Student

November/December 2025

Biodiversity is how diverse an ecosystem is. There are three main types to note when talking about biodiversity: genetic diversity (the range of characteristics), species diversity (how many different species exist and their abundance of), and habitat diversity (how many are present in an ecosystem). These factors are all crucial for how an ecosystem responds to stressors.

While natural disruptions to an ecosystem are generally fine, it is humans who make the largest and worst impacts to the environment. Our impacts not only affect the ecosystem’s environment, but also the living organisms that live there. The biggest way we do this is through urbanization.

Urbanization is how the human population grows and spreads. It is how people move away from rural living to cities and/or towns. During the mid-18th century, the world experienced the first Industrial Revolution, in which we shifted from and agricultural economy to a blue-collar economy. Less people were working on farms because we found ways to feed the constantly growing population without the need for as many farmers. This led to more people working in offices, going to school, and working in safer working climates where you did not have to rely on natural forces for whether or not you can make a living. This seems like a good idea (and it mostly is!), however, things started going downhill once humans started building “out” rather than “up.” According to the United Nations website, around 55% of the world’s population lives in an urbanized area, with 83% of Americans living in urban areas.

It seems like urbanization is the worst thing that could ever happen to the world, but that is not necessarily true. There are some positive impacts that go along with urbanization! Urban areas (cities) are much more dense than rural areas, allowing many places to be left untouched. Since everything people could need are all found in these highly populated areas, less people are traveling through these natural lands, allowing them to be left to the wild organisms who rely on these areas. Birth rate is also a frequently discussed topic, and urbanization is a smaller solution out of many for that. Buildings used to house people in urban areas are typically smaller, making people not want to have as many or any kids due to the lack of space. This contributes to a slow decline in the human population, which many will argue is a good thing for the world’s environments.

That being said, urbanization is still a negative thing for the environment and biodiversity. For example, urbanization takes resources away, whether it’s for lumber, coal, land, etc. By taking away trees and land, you are contributing to habitat loss because many organisms rely on these to survive and thrive. Without it, they will die of, causing the biodiversity (especially species diversity) to decrease. With the destruction of natural habitats comes a declining diversity. Urbanization also contributes to fragmentation, which is the separation of natural land with human settlements and roads. When the habitats are separated, the species cannot travel back and forth through the ecosystems, causing them to die off, decreasing their population.

Earlier, I mentioned how urban areas are growing “out” rather than “up.” This is called “urban sprawl,” showing how these areas are sprawling outwards at a fast rate. While this decreases a density in a given area, it still is extremely harmful to all the surrounding habitats, which are being destroyed to make way for human infrastructure. These large areas cause pollution (light, Co2, etc) and destroy everything in its path, as well as breaking up the ecosystems that could potentially have been connected.

While there is no single solution for how urbanization hurts biodiversity, it is still important to recognize our own habits and be conscious of how bad this issue is becoming. Rather than growing our cities out, we should allow our fellow life forms to thrive just as we do.