Why some places are prime targets for invasive species

Invasive species pose a threat to ecosystems worldwide. They disrupt native habitats, outcompete local species, and create long-term ecological challenges.

Scientists have struggled to predict where these species will spread next, as their movements are often unpredictable. This unpredictability makes it difficult for conservationists and policymakers to develop effective strategies to contain or prevent their spread.

The spotted tilapia is just one example of an invasive species that continuously moves into new environments. These alien species adapt quickly, making it hard for researchers to simulate their movements.

Traditional climate-based models provide some insights, but they often lack accuracy in forecasting future invasions.

Researchers at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) set out to refine these predictions by taking a deeper look into what makes certain areas more susceptible to invasion.

Better way to predict invasive species

The scientists identified a missing piece in existing invasion models. They proposed an updated approach to environmental resistance (ER) modeling, which accounts for factors beyond just climate conditions.

This new method provides a better understanding of why some areas are more vulnerable to invasions than others.

Environmental resistance measures how difficult it is for an invasive species to establish itself in a new habitat. One of the key factors influencing this difficulty is the similarity between the native species in a given area and those in an already invaded region.

If a new location has native species that are similar to those in an invaded area, it is more likely to experience an invasion.

An invasive species is more likely to spread to areas where native species resemble those in already invaded regions.

This study focused on the eastern United States, a region heavily impacted by invasive species. Florida, for example, has more invasive vertebrates than any other state. Meanwhile, the Great Lakes region and the Northeast face significant challenges from invasive plants.

Understanding the patterns of invasion in these regions helps researchers determine which factors play the most significant role in either allowing or preventing the spread of non-native species.

Testing new models for prediction

To refine ER modeling, the scientists considered several environmental factors. Traditional climate-based models assume that if an invasive species thrives in one location, it will do well in a similar climate elsewhere.

However, this approach has its limitations. It does not account for how quickly invasive species can adapt to new conditions or how existing ecosystems might resist their spread.

Yunpeng Liu is a postdoctoral researcher at UF/IFAS and lead author of the study.

“Most important, traditional modeling strategies do not predict invasion spread well if we do not know much about the suitable climates of the invasive species or we are not sure about their adaptation after they colonize into new habitats,” said Liu.

“What we came up with is an update to ER modeling that adds the necessary layer that has been missing.”

The researchers tested different versions of ER modeling, incorporating factors such as soil type and human activity. They simulated real-world invasion patterns and compared which models most accurately predicted the spread of invasive species.

The results revealed that models based on native species similarity were the most effective in predicting invasions, outperforming those based on climate and other environmental factors.

Why native species similarity matters

One of the most important findings of the study was that native species similarity played a crucial role in predicting invasion spread. When native species in an area resemble those found in an already invaded region, the risk of invasion increases significantly.

“The ER model based on native species similarity was the best model for predicting current spread, not just for invasive plants but also a suite of invasive animals,” Liu explained.

This insight challenges previous assumptions that climate is the dominant factor in determining where invasive species will thrive. While climate remains important, the interaction between native and invasive species is often a stronger predictor of whether an invasion will succeed.

Climate change impact on invasive species

As temperatures shift due to climate change, ecosystems will experience transformations that could make them more or less vulnerable to invasion.

Native species distributions will change, potentially increasing the similarity between previously distinct ecosystems. This could create new opportunities for invasive species to expand into areas where they previously could not survive.

“The findings suggest that native species groupings could become more similar in the future than what they are today, leading to an increase in the spread of most of the invasive species, especially for those who have already occupied a wide range of habitat,” Liu said.

Urban areas, particularly those near large cities in Florida, are likely to face the highest risk. As human activity alters natural landscapes and climate shifts continue, these regions may become hotspots for future invasions.

Applications and conservation efforts

The findings of this study provide valuable insights for ecologists, land managers, and policymakers. Understanding the relationship between invasive species and native biodiversity allows experts to take proactive measures before an invasion occurs.

Rather than relying solely on climate-based predictions, conservationists can now use ER modeling to identify areas at the highest risk of invasion.

One key takeaway from the research is the importance of preserving the unique composition of native species in different regions. If native species become too similar across different environments, it could create more opportunities for invasive species to spread.

Conservation efforts should prioritize maintaining the diversity of native ecosystems to strengthen their natural resistance against invaders.

Progress in managing invasive species

This study marks a significant advancement in predicting and managing invasive species. By refining ER modeling and focusing on species similarity, researchers have developed a more accurate tool for assessing invasion risk.

This approach not only helps scientists better understand the spread of invasive species but also provides land managers with the knowledge needed to protect vulnerable ecosystems.

As invasive species continue to challenge native habitats, innovative research like this plays a critical role in shaping conservation strategies.

With a better understanding of how invasive species interact with their surroundings, experts can implement targeted solutions to safeguard biodiversity and maintain ecological balance.

The study is published in the Journal of Biogeography.

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