How climate change accelerates invasive species spread and threatens biodiversity
By Rose Morrison, managing editor of Renovated.
Life on planet Earth has faced increasing threats in recent decades, driving significant biodiversity loss and ecological damage. Yet, increasing climate change and an influx of invasive species may create the most negative consequences for indigenous plants and animals.
The threats of invasive species on biodiversity are widespread, with global repercussions for fragile ecosystems. Climate change especially generates favorable conditions for intruders to establish themselves elsewhere, as it destabilizes precipitation trends and drives warmer temperatures.
Defining Invasive Species: What Are They and How Are They Introduced?
The best invasive species definition is non-native flora and fauna within an ecosystem that does not naturally belong. Oftentimes, their presence has the potential to harm the environment, biodiversity and human health.
Humans usually introduce invasive species into a particular area by transporting goods or intentionally or accidentally releasing them into the wild. Likewise, insects might hide in wooden shipping palettes that traverse the seas. Similarly, non-native plants may grow wild after their seeds make it to land from transport carriers.
The giant African snail is a prime example of an intruder in North America, having found its way to the environment after being kept as a pet, eaten as a delicacy, used for medicinal reasons or studied in research. It is listed as the second worst of 100 invasive species globally. The prevalence of these snails throughout Florida, in particular, has damaged the state’s agricultural sector.
Another troublesome invasive species is the Oriental bittersweet, an aggressive woodland plant from Korea, China and Japan introduced to the United States around 1860 to help with erosion. It’s a difficult plant to control — growing 60 feet long and up to 4 feet in diameter — and competes with indigenous flora for sunlight and nutrients.
How Do Invasive Species Affect Biodiversity?
According to a 2023 Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services report, over 3,500 of the 37,000 alien species introduced by humans severely threaten nature. The report also found that invasive species are a major reason for 60% of global extinctions, while 16% are solely responsible.
Under the right conditions, non-native species aggressively encroach upon ecosystems, much to the detriment of biodiversity. For example, invasive plants may cause significant declines in native flora, with some even going extinct. They might also consume ample water resources and alter soil composition, making it difficult for native plants to flourish.
Invasive animals have similar impacts on biodiversity, preying on native wildlife, disrupting the food web and causing population declines. Some carry diseases into habitats, jeopardizing endangered and threatened species. Additionally, they might interbreed with native species and cause genetic changes, such as wolf-coyote hybridization.
Climate Change as a Driver of Non-Native Species Distribution
Rising temperatures, altered precipitation trends, extreme weather and increased carbon dioxide (CO2) emissions have driven the spread of invasive species. In fact, as the world warms, scientists believe the establishment of non-native plants will increase by 36% by 2050. Approximately 17% of global terrestrial ecosystems will also become susceptible to alien flora.
Climate change notoriously melts sea ice, creating new routes for intruders to enter ecosystems on ships and in ballast water. Ballast water is saltwater held in ship tanks for greater stability, especially when the ships aren’t carrying cargo. The warmer temperatures also enable alien species to expand their range, while frequent flood events and hurricanes may transport invasive species to different areas.
The effects of CO2 on invasive plants are especially of grave concern to scientists, considering elevated levels may stimulate their growth. Excess CO2 boosts photosynthesis in 90% of plant species, altering plant biology.
Examples of Invasive Species and Their Biodiversity Impacts
To understand the true impact of invasive species on biodiversity, it is best to look at real-life examples, including climate change’s effect on their distribution. Around the world, non-native species wreak havoc on precious ecosystems and indigenous plants and animals. Here are four alien species posing the most severe consequences.
Non-Native Phragmites in the Midwest
The Oneida Nation of Wisconsin’s Environmental Health and Safety Division maintains over 20 natural areas and recreational trails, preserving and restoring the local environment and natural resources. Unfortunately, invasive phragmites — common reed — have encroached on the Midwest region, overtaking native flora and reducing visibility alongside roads, sidewalks and waterways.
Phragmites are native to Europe and Asia and originated in the Middle East. Cargo ships carried it into the Great Lakes during shipping operations, and people discovered it sometime in the late 1700s and early 1800s.
The common reed modifies hydrology and habitat for local wildlife and also increases wildfire risks during dry seasons. The plant can quickly recover from cutting, grazing, and prescribed burns because of its resilience and rapid stem growth, which extends 6 feet deep and 10 feet horizontally.
Burmese Pythons in the Florida Everglades
The Florida Everglades are among the most critically endangered ecosystems worldwide due to widespread non-native species. Burmese pythons are especially dangerous to biodiversity, including the threatened and endangered little blue heron, roseate spoonbill, Big Cypress fox squirrel, Key Largo woodrat and Key Largo cotton mouse.
South Floridians introduced the large snake to the ecosystem in the late 1990s and early 2000s, where they soon began reproducing. Four decades later, the Burmese python population has grown, and its invasion is spreading north.
According to a 2023 study, local climate and weather patterns greatly impact the snake’s physiology, development and behaviors. Scientists are now examining climate models to predict where they might migrate next. Because they effectively seek shelter 30 centimeters underground during cold fronts, it could enable them to move into southwestern Georgia.
Lionfish in the Atlantic Ocean
Lionfish are the perfect example of invasive species spreading due to climate change. Originating in the Indo-Pacific, lionfish have made their way to the warming waters of the Atlantic Ocean, Gulf of Mexico and Caribbean. Unfortunately, rising ocean temperatures enable this tropical, venomous fish species to spread north and south, where they can colonize.
Lionfish prey on many coral reef fish species and have very few predators themselves. The presence of one lionfish can decrease native fish recruitment by 79%, negatively affecting local fisheries and the health of reef ecosystems. For example, lionfish eat herbivores, which consume algae. Excess algal growth can place undue stress on coral reefs.
Sonneratia apetala in Brazil’s Mangrove Forests
Mangrove forests are one of the most important ecosystems on Earth, sequestering 28 million metric tons of carbon dioxide annually, filtering pollutants, stabilizing shorelines and serving as a nursery for juvenile fish. However, climate change exacerbates the spread of aggressive Sonneratia apetala in Brazil’s mangrove ecosystems.
S. apetala was first introduced in China in 1985 to aid mangrove restoration. However, scientists believe cargo ships carrying ballast water introduced the species’ seeds to Santos Port, a mere 1.2 miles from the mangroves. The seeds had a 14.7% survival rate during germination studies, according to biologist Geraldo Eysink.
The plant is highly adaptable and fast-growing, causing grave concern for the Cubatão Baixada Santista Estuary. Eysink’s research has identified five S. apetala specimens 70 meters into the mangrove basin, where it can alter the environment and hurt the area’s biodiversity.
How Scientists Are Controlling Invasive Species
Understanding how invasive species affect biodiversity is only part of the bigger picture. It is equally important to consider climate change’s complicated relationship with alien species if the world hopes to sustain and protect life on Earth.
Scientists are utilizing cutting-edge technology to monitor the spread of non-native species and collect information about biodiversity loss and indigenous species revival. For some time, the agricultural sector has deployed drones to track pest infestations and improve yields. These aerial cameras are especially useful in collecting precise data in places with limited accessibility, enhancing farmers’ decision-making.
Drones play a similar role in conservation, enabling researchers to identify and observe invasive species populations. In one study, scientists used drones to examine common milkweed and blanket flowers in Hungary’s Lake Kolon grasslands. The results indicated that drones could help determine species density and invasion, allowing conservationists to select the proper treatment to eradicate them.
Other methods for targeting and controlling invasive species include the following:
- Using biological control agents like plant-eating insects and fish
- Applying chemical control, like herbicides and insecticides (however, these can be just as harmful to the planet)
- Inspiring changes in human behaviors and educating the public to avoid the spread of invasive species
- Mulching, prescribed burning, steam-weeding, and organizing prescribed grazing with herbivores
- Eliminating non-native species through mowing, tilling, chopping and other mechanical measures
- Removing intruders by hand, such as collecting nests or pulling invasive plants from the ground
Naturally, the most effective method to control alien plants and animals from affecting biodiversity is to prevent their spread in the first place. You can help by joining efforts to remove invasive species throughout your community, planting only native flora in your garden and avoiding releasing exotic pets in the wild. Additionally, reducing your carbon footprint can help curb the climate crisis and reduce harmful species invasions.
Protecting Biodiversity Against Climate Change and Invasive Species
Climate change and invasive species present real challenges for biodiversity separately and even more damaging effects together. Rising temperatures and changing ecological conditions allow non-native species to further destabilize fragile ecosystems, threatening nature’s delicate balance and essential resources. Addressing these crises on a global level and actively eradicating invasive populations is the only way to protect indigenous flora and fauna for years to come.
About the Author
Rose is the managing editor of Renovated and has been writing in the construction, landscaping and sustainable building sectors for over six years. She’s most passionate about improving environments, reducing carbon footprints and incorporating resourceful methods to promote well-being in the planet. For more from Rose, you can follow her on Twitter and connect on LinkedIn.