by Erin Hathaway

Invasive species, a Colombian drug lord, and hippos are not commonly associated – that is until recently. As one the world’s top drug lords, Pablo Escobar used his wealth to create a personal zoo on his estate. At the end of his reign, officials dispersed many of the animals to other regional zoos but left a small herd of (4) hippos on the property, and no one thought twice.

Transported from Africa, the hippos thrived in the similar Colombian climate. Today, the growing herd is up to an estimated 60 hippos, after just 20 years, and moving into other bodies of water in the region. The country’s expansive waterways make it easy for the hippo population to spread across the country and without native predators their growth is uncontrolled. Not only are the hippos a threat to the native Colombian ecosystem, but they are also becoming a challenge to the community. In addition, many people claim to “adopt” baby hippos found in the wild without understanding that these animals grow to massive sizes and are known to kill humans.

Invasive species are a worldwide epidemic threatening ecosystems and costing billions of dollars to control. Like the story of Escobar’s Hippos we don’t realize the impact of our choices in the future. Most often people buy exotic species to have as pets but eventually release them into the wild when they can’t or don’t want to take care of them. This is the case for the largest snake in the world that now calls the Everglades home. The Burmese Python was and still is a popular exotic pet but are often released into the wild when the owners realize the snakes size and strength are too much to handle for a pet. The Everglades is the largest subtropical wilderness in the United States and an ideal environment for the pythons. With similar conditions to the python’s native Asian climate, the species thrives. However, the python interrupts the Everglades ecosystem and competes with other top predators for food. Since 2005, the U.S. Fish and Wildlife Service has spent more than $6 million to control and attempt to eradicate this species and other large invasive snakes in Florida.

The Great Lakes ecosystem is highly valuable and threatened as a direct result of invasive species. The Asian Carp came to the United States not as a pet but rather as a way of controlling algae. They were brought into aquaculture and sewage treatment facilities to filter water in the 1970s because of their ability to consume large quantities of plankton. Consequently, this has had detrimental effects on our freshwater ecosystems. After a flood allowed them to escape, the carp made their way into 23 states and represent over 97% of the biomass in portions of the Illinois and Mississippi Rivers. Many organizations are trying to stop their expansion before the fish reach the world’s largest freshwater ecosystem, the Great Lakes.

In addition to threatening the Great Lakes ecosystem, the carp could devastate the Great Lakes $7 billion fishing industry, further threatening the $16 billion boating industry, and harm fisheries. Physical barriers and chemical control methods have been implemented to control the carp population but a complete hydrologic separation between the Great Lakes and the Mississippi region is believed to be the only way to prevent the species from showing up in the Lakes. The U.S. Army Corps of Engineers estimates the barrier to cost as much as $18 billion.

Invasive species are more common that we think and in many cases don’t appear to be invasive at all. While recently visiting a project site in California, I was drawn to a beautiful flower unfamiliar to me on the east coast, a Cynara cardunculus, also known as a Cardoon or Artichoke thistle. Turns out Artichoke thistle are invasive much like their related Canada thistle found on the east coast. Artichoke thistle are thought to be originally brought to the California area for their ornamental and culinary use. Originally from the Mediterranean region of Europe, California’s sandy arid climate was a perfect match for the species. The plant spreads fast and can form thick spiny stands creating barriers to wildlife movement. The aggressive root system outcompetes native species and leads to a thistle dominated landscape with little plant diversity. The fragmentation of the landscape and the decrease in biodiversity has caused a California wide effort to eradicate these weeds. Who knew such beautiful flowers could be so harmful to our ecosystem.

With more than 50,000 invasive species in the United States, control and eradication of invasive species is a top priority to protect and support native ecosystems. As a society, we recognize the valuable services – economic, social, and environmental, provided by a highly functioning ecosystem. To protect these services, such as those provided by the Great Lakes, the U.S spends almost $120 billion per year on invasive species control and eradication. (Pimentel, 2005). Despite appearances as beautiful plants, exotic pets, or even other invasive species controls, we must think critically before introducing a nonnative species into an area.