There are more and more people in the world. According to a 2015 United Nations report, there may be 9.7 billion of us by 2050! But there’s also another number going up: the number of different species going extinct. Just how many is under debate, but many scientists believe that we are in the midst of a mass extinction.
Did you know? There have been five known mass extinctions on earth, each of which killed off over 50% of the species on the planet at that time.
Is there a link between these two increases?
Right now, many people are focused on trying to support and sustain the human population. But to decrease the number of species going extinct, humans need to allow all species to flourish - not just our own. To do this, we need to understand the many problems humans pose for the Earth’s biodiversity. Let’s look at three of these problems in more detail: habitat loss, overhunting and overfishing, and introducing invasive species.
More people means more space needed. Growing populations usually mean growing cities, suburban sprawl and more factories. This can lead to a variety of consequences.
One example is habitat fragmentation. This is the process where an area that a species is living in gets broken up into smaller habitats. For example, a highway might get built through what was once a forest. The highway divides that forest and separates its population.
A more serious consequence is habitat destruction. That’s exactly what it sounds like: in order to support human growth, habitats like forests and wetlands are altogether destroyed.
There are things humans can do to reduce these problems. For example, to reduce habitat loss of forests, people can replace cut-down trees with new trees. People can also go paperless, reducing the need to cut down trees in the first place.
Did you know? The Florida Panther is a victim of habitat loss. They once ranged throughout the southeastern United States. Now, they are an endangered species - and they all live in Southern Florida.
Hunting and Fishing
More people generally means an increase in these two activities. And they put a large strain on a species’ ability to sustain itself.
History has many examples of hunting (including poaching) and fishing affecting species extinction rates. For example, overfishing is one of the main reasons why the North Atlantic cod population in Atlantic Canada crashed in the early 1990s. Humans can reduce this damage by reducing how much hunting they do, and by following government regulations around hunting and fishing endangered species.
Did you know? Canada has a Species at Risk Act, which protects Canadian wildlife from disappearing.
Introducing invasive species to new habitats
More people means more demand for easier ways to transport and ship things. This has correlated with an increase in invasive species. These are species that get introduced to a new location. They can then spread to the point that they can damage the environment and threaten other local species.
An example of an invasive species in Canada is the Zebra mussel. Mainly found in Eastern Europe in the 18th century, the zebra mussel likely hitched a ride in the ballast of a cargo ship and ended up in the Great Lakes. Zebra mussels can produce up to one million eggs in a spawning season. It’s no surprise that these mussels quickly became a dominant force in the Great Lake Region. They can cover indigenous organisms like freshwater clams so that they are unable to feed. Because of this, the population of freshwater clams in this region have decreased dramatically. Zebra mussels can also disrupt aquatic ecosystems by consuming most of the phytoplankton found there.
Above: Zebra mussels. Image © D. Jude, flickr.com.
The broader picture
You depend on biological diversity in your day to day life in ways you may not realize. For example, biological diversity may be able to protect ecosystems from large changes in climate. Studies have shown that ecosystems with more biodiversity have higher resistance for a broad range of climate events such as extreme wet or dry seasons. Biodiversity provides social benefits, too. Ecosystems can provide us with beautiful areas to turn into parks, biking trails, and tourist spots around the world (though this, like all human activities, must be done in a sustainable way).
Above: California State flag. Image © Devin Cook, Wikimedia Commons
Did you know? The California state flag features the last known captive California grizzly bear. The bear, named Monarch, died in 1911. The last grizzly was killed in California in 1924.
As species extinction continues to rise, we humans must protect endangered species and limit our impact on biological diversity.