Will extreme climatic events facilitate biological invasions?
Diez, J. M., D'Antonio, C. M., Dukes, J. S., Grosholz, E. D., Olden, J. D., Sorte, C. J., ... & Jones, S. J. (2012). Will extreme climatic events facilitate biological invasions?. Frontiers in Ecology and the Environment, 10(5), 249-257. PDF.
Summary
More often, climate change + invasive species research investigates the impact of gradual shifts in mean climate conditions. Less is known about how invasive species will respond to the increased frequency and intensity of extreme climate events such as storms, floods, droughts and fires. Diez et al. (2012) review examples and theory behind invasive response to extreme climate events through the mechanisms of dispersal, disturbance, resource pulses, and physiological stress (Table 1). While many invasive species disproportionately take advantage of these extreme events (e.g. grass-fire, flood -related dispersal, heat-related mortality in natives), there are instances where native species may benefit (e.g. floods can benefit fish in semiarid systems, and some natives are resistant to prolonged drought conditions). The paper concludes that invasive responses to extreme climate events are both complex and context dependent. The authors highlight the need for future research on how extreme climate events will affect the level of invader impacts, as well as invasive/native system traits that are likely to be impacted by extreme climate events.
Take home points
More frequent climate extremes (floods, droughts, heat waves, hurricanes) are projected with climate change.
Ecological theory strongly suggests that increased invader impacts are likely following extreme events.
Extreme events can increase invader dispersal and reduce native community resistance to invader establishment, but events do not always favor non-natives.
Making accurate predictions will require more evidence of interactions between extreme events, the invasion process, and species interactions.
Management implications
Understanding traits and demographic characteristics of invaders can facilitate targeted management efforts, e.g. focus on species that have a high likelihood of invasion following extreme events (e.g. vines after hurricane, grass after fire), focus restoration efforts where they will increase community resilience to extreme events.
Extreme events can happen anywhere, and unexpectedly. To measure ecological response following extreme events, information about the state of the ecosystem 'before' is critical. Any quantitative surveys of species abundance would greatly improve our ability to assess changes following extreme events.
Models based on manager-driven observations can be extremely helpful for evaluating the efficacy of future management actions (scenario analysis).
Keywords
Novel Introduction Pathways; Climate Extremes; Review; Risk Assessment