Invasive Species and Climate Change

               Climate change is having a massive impact on the biodiversity and health of many ecosystems across the globe. The mechanisms by which vary from species to species and include everything from increasing temperatures to the pH of the oceans. Another major driver of biodiversity loss is the spread of invasive species. When an invasive species is introduced to and catches on in a new environment where it is not native, it will generally cause damage to that new environment and the native species that live there in a cascade of biodiversity loss. This is mostly due to a lack of competition or predation it has with the natives that allow it to grow and spread way out of control and affect everything else around it. As it turns out, the spread of invasives is closely connected to climate change in a number of cases. For example, warmer winters and higher waters can allow species to inhabit new environments where the conditions weren’t previously favorable for them.

An easy example of this is the Kudzu plant in the southern United States, that literally grows over and strangles the native life out of entire swathes of land.

(Image: https://www.nature.org/en-us/about-us/where-we-work/united-states/indiana/stories-in-indiana/kudzu-invasive-species/)

Kudzu was first introduced to the United States from Southeast China and Japan in 1876. Later, it was actually touted as a way to control soil erosion by the Soil Conservation Service from the 1930s to the 50s. It has since spread over the entire southern United States, causing massive damage wherever it goes. Due to the flexible and adaptable nature of invasive species, the stress put on them by a changing climate doesn’t hit them as hard as it does specialized natives. Kudzu’s spread has previously been limited by cold winters in the northern United States. Our warming winters are allowing this destructive plant to slowly spread further and further northward in the continental United States.

Another example of the spread of an invasive species due to climate change is the Mountain Pine Beetle. The Mountain Pine beetle is native to western Canada and primarily feeds on the phloem of pine trees.

(Image: https://www.parkrapidsenterprise.com/opinion/mountain-pine-beetle-is-no-1-invasive-insect-priority)

Like the Kudzu, these beetles have historically been cold limited organisms. Warming winters have also allowed them to spread across the entire country which leads to a mass dying of trees. This is a double-dangerous situation, because on top of it leading to mass tree damage, it also affects the ability of these forests to act as carbon sinks. A large outbreak of these beetles could actually turn some of Canada’s forests into carbon sources.

Warming winters aren’t the only aspect of climate change that allows the increased spread of invasives. Climate change is also opening up new routes for invasives to spread, including more polar shipping routes. Additionally, climate change is making existing tools for the detection and control of invasives less effective. Agencies such as the U.S. Geological Survey and the USDA are currently working on improving the tools we use to monitor and mitigate the damage invasive species can cause.