A recent international study has revealed that non-native species are expanding their ranges significantly faster than native ones, primarily due to inadvertent human assistance. Even seemingly sedentary non-native plants are moving at three times the speed of their native counterparts. This rapid movement is crucial as climate change accelerates habitat shifts. To survive, species need to shift their ranges by 3.25 kilometers annually; a pace native species cannot achieve without human help.
Led by scientists from the University of Massachusetts Amherst, the research team comprised experts from New Jersey, Michigan, Colorado, Hawaii, and Spain. Their findings were published in the Annual Review of Ecology, Evolution, and Systematics. Bethany Bradley, a professor of environmental conservation at UMass Amherst, highlighted the exponential increase in invasive plant species worldwide and the role of plant nurseries in exacerbating this climate-driven spread. The team’s primary goal was to measure the current movement rates of both native and non-native species and project their potential spread.
Bradley and her colleagues conducted an exhaustive review of existing literature and datasets to determine how far and fast various species move across different taxa and ecosystems. The research also focused on human activities that accelerate the spread of non-native species, whether accidentally, such as through shipping containers, or intentionally, such as the purchase of invasive plants from nurseries.
The study concluded that land-based species need to move more than 3.25 kilometers per year to keep pace with climate change, while marine species need to move 2.75 kilometers yearly. However, native species only move an average of 1.74 kilometers per year. In contrast, invasive species naturally spread at approximately 35 kilometers per year. When human influence is considered, this rate skyrockets to 1,883 kilometers per year, making it 1,000 times faster than the movement of native species.
Bradley emphasized the bleak outlook for native species adapting to climate change without human intervention. The second phase of the research aimed to predict how far native and non-native species might spread in a warming world. The findings suggest that non-native species may find more suitable habitats than native species but also risk losing territory as climate change renders some areas unsuitable.
The study demonstrates the effectiveness of human-assisted migration in supporting native species. Bradley advocates for this practice to give native plants and animals a fighting chance against the rapid changes brought on by climate change. The research calls for urgent implementation of strategies to mitigate the competitive advantage of non-native species and ensure the survival of native ecosystems.
