Kudzu on Trees in Atlanta, GA
As the climate warms, the number of alien species on every continent is expected to increase by 36 percent by 2050. Some of these alien species, which are plants or animals that live outside their natural range, are invasive and can harm ecosystems and the areas they invade, leading to serious impacts on the global food supply, medicines, water quality, biodiversity, and livelihoods.
Rising temperatures, increased CO2 levels, and extreme weather conditions that alter landscapes all contribute to the spread of invasive species. This exacerbates climate impacts by making habitats, agriculture, and cities less resilient. For example, when invasive plants overrun native plants and create monocultures, the area becomes more susceptible to wildfires or pests, intensifying the effects of climate change.
What are invasive plants? Not all alien or non-native plant species are invasive. Invasive plants are defined as those that adapt easily to new environments, reproduce quickly, and damage the native species, ecosystems, property, or economy of their new habitat. Many food crops, such as wheat, rice, tomatoes, and garden plants, are non-native but not invasive.
Plants must go through five stages to be considered invasive:
- Transport
- Introduction
- Establishment
- Spread
- Impact
While there are traits associated with plants that spread successfully, these characteristics must be well-suited to the specific environment in order for the plants to increase in abundance. Invasive plants are typically fast-growing, produce many seeds that are easily dispersed, and can adapt to a variety of soil conditions.
Invasive plants can reduce water quality, disrupt ecosystems, alter food webs, and degrade wildlife habitats. They can turn diverse ecosystems into monocultures, making them susceptible to collapse. Islands are particularly vulnerable to invasive plants, where they outnumber native plants on more than 25% of all islands.
Climate change affects invasive plants, as new environmental conditions define every species as a potential new colonizer. A warmer world is causing species to shift their ranges northward and to higher elevations. Warming temperatures mean earlier springs, giving invasive plants a longer growing season.
Increased CO2 levels in the atmosphere can help some plants grow faster, with certain invasive plants using higher CO2 levels more efficiently than native plants. Monocultures and trees stressed or damaged by invasive plants sequester less carbon and may experience more wildfires that emit CO2 into the atmosphere.
Land that is disturbed by extreme weather provides opportunities for invasive plants to establish themselves. It is essential to understand the impact of invasive plants and take measures to mitigate their spread to protect our ecosystems and environment.
