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Observed and Potential Range Shifts of Native and Nonnative Species with Climate Change

Friday, June 28, 2024

Understanding species’ potential range shifts in response to climate change involves two main components.  First, how fast are species able to move (observed spread)?  Second, how much space does the species have to move into (potential spread)?  Faster-moving species with larger ranges to expand into have a higher likelihood of surviving in a changing climate.  Researchers and practitioners are concerned that non-native species will have an advantage in shifting their ranges with climate change. A new publication by a team including NE CASC researchers Bethany Bradley and Toni Lyn Morelli reviews observed and potential spread of native versus non-native species, showing that these concerns are well founded.  In terrestrial systems, species need to move an estimated 3.25 km/year just to keep up with the current pace of climate change.  Non-native species are spreading at an average rate of 35 km/year, more than 20 times faster than native species.  These numbers illustrate that non-native species should have no problem shifting their ranges in response to climate change. In contrast, many native species, particularly slow-moving taxa like plants, will be unable to keep up without help.  However, if native species had assistance like non-native species do, many more native species would be likely to persist with climate change.

In addition to spreading much faster, non-native species also appear to have larger potential ranges than native species, giving them more area to expand with climate change.  This is likely due to the broader climatic tolerance of non-native (and especially invasive) species as well as their release from natural enemies.  Species with large potential ranges currently also tend to have large potential ranges with climate change, which means that they have more area of expansion and more area of contraction.  Area of expansion can be interpreted as risk from range-shifting species; area of contraction could create potential for restoration, but the loss of invasive species due to climate change has not yet been documented on the ground.  Collectively, this review underscores the clear advantage that non-native species have in a changing climate.

Take-Home Points

  • Native species, particularly plants, need to move orders of magnitude faster than their current rates to ‘keep up’ with the pace of climate change.
  • Native species moving too slowly is consistent across taxa and across terrestrial, freshwater, and marine systems.
  • Non-native species across taxa and systems are readily keeping pace with climate change, likely due to human-mediated spread combined with faster natural spread rates.
  • Non-native species, particularly plants, tend to have larger ranges and therefore might have more area to expand into with climate change.

Management Implications

  • Most native species need human assistance to expand their ranges. 
  • Non-native species, and especially invasive species, tend to have broader climate tolerance and therefore will have larger areas of potential range expansion with climate change. 
  • Non-native species also have larger areas of potential range contraction, and restoration opportunities could result from these changes.

Additional Information