Climate change and biological invasions: evidence, expectations, and response options
Hulme, P. E. (2017). Climate change and biological invasions: evidence, expectations, and response options. Biological Reviews, 92(3), 1297-1313. PDF.
Summary
Hulme (2017) conducted a literature review to address the role of climate change on the establishment and spread of alien species, as well as their anticipated economic and ecological impacts in the future (see Table 1). Given that the rate of climate change is expected to vary globally and management is typically conducted on a national-scale, the author focused on a regional assessment of Great Britain. Hulme concluded that Great Britain is at great risk to future invasions since it is climatically similar to many regions of the world, and only a small fraction of the species native to those areas have been observed in Great Britain. The risk of introduction of these species is expected to increase by both unintentional (via range expansion) and intentional (via increased trade) pathways. The author also warned of the potential increase in “sleeper” species. These are species that currently reside in Great Britain either in greenhouses or gardens, but cannot spread due to an inability to overwinter and reproduce successfully under current (colder) conditions. Of the alien taxa, Hulme identified arthropods as the biggest threat under future climate change due to their ectothermic physiology, high dispersal rate, likelihood of travelling to GB unaided, their strong association with trade, and commensal relationships with human environments. Pests and pathogens may also increase due to prolonged growing seasons.
Take home points
Regional assessments (rather than global assessments) offer a more logical approach for assessing the role of climate change on biological invasions given climate change conditions are expected to vary widely globally and management is typically implemented on a regional scale.
“Sleeper” species are likely to be the biggest threat under future climate change. On average, many alien taxa (i.e., mammals, birds, fish, algae, amphipods, and plants) will respond positively to future climate warming; however, arthropods are anticipated to fare the best due to improved growth and overwintering survival.
Management implications
Many introduced species have not arrived in Great Britain. Although the risk of unintentional introduction will be elevated under climate change, the contribution of species via this pathway will pale in comparison to deliberate introductions. Therefore, improving preventative measures (e.g., more stringent border inspections) will provide the most cost-effective measures in managing future biological invasions.
Research Needs
Develop a standardized protocol (e.g., EICAT) that identifies which of the “sleeper” species could result in the most detrimental impacts under future climate change.
Use bioclimatic modeling to identify which ecosystems are most at-risk to invasion and then prioritize management efforts accordingly.
Bioclimatic modeling has only been applied to handful of established species. Expand modeling in order to identify the potential distributions of establish species.
Gaps in knowledge (e.g., uncertainty in the role of natural spread, lack of information on aquatic realms, insufficient information for bioclimatic model parameters) limit our ability to predict the risk of impact of invasive species in the future. Continued data collection focused on better understanding dispersal mechanisms, aquatic ecosystems, ecophysiology, and species interactions is recommend to improve our knowledge of biological invasions under future climate change.
Keywords
Novel Introduction Pathways; Review; Risk Assessment