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The Ants are Coming! The Ants are Coming!! ... or Are They????

Paper Reviewed
Bertelsmeier, C., Luque, G.M., Hoffmann, B.D. and Courchamp, F. 2015. Worldwide ant invasions under climate change. Biodiversity Conservation 24: 117-128.

In a study published in Biodiversity Conservation, Bertelsmeier et al. (2015) write that "there is a general, yet untested, consensus that climate change will exacerbate the threat posed by invasive species," which they say is especially the case for ectotherms like ants, the current distributions of which "are limited by thermal barriers," citing Dukes and Mooney (1999), Brook et al. (2008) and Hellmann et al. (2008). Surprisingly, however, they report that (1) very few studies have included climate change in their projections in order to test this assumption, and that (2) no global assessment predicting future ant invasions has ever even been attempted.

In a recent attempt to fill this void, therefore, and noting that "ant distribution is largely limited by climate (Roura-Pascual et al., 2011)," and that "ants are among the most invasive organisms (Lowe et al., 2000)," the four researchers conducted the first global risk assessment of invasive ants driven by projected future climate change, focusing on 15 of the world's 19 most invasive ant species as determined by the Invasive Species Specialist Group of the International Union for the Conservation of Nature.

Working with techniques that explain a species' distribution based on a set of climatic predictor variables, therefore, Bertelsmeier et al. created a set of consensus models using five different techniques -- three Global Circulation Models and two Special Report on CO2 Emission Scenarios -- to include "a wide range of possible future climatic conditions," which they used to compare changes in suitable ant-inhabited area over time, both globally and regionally. And what did they thereby learn?

In the words of the four researchers, "surprisingly, the potential distribution of only five species was predicted to increase (up to 35.8%) with climate change [to 2080], with most declining by up to 63.3%." And they therefore conclude that "contrary to general expectations, climate change will not result in range expansion for most [ant] species."

Brook, B.W., Sodhi, N.S. and Bradshaw, C.J.A. 2008. Synergies among extinction drivers under global change. Trends in Ecology and Evolution 23: 453-460.

Dukes, J.S. and Mooney, H.A. 1999. Does global change increase the success of biological invaders? Trends in Ecology and Evolution 14: 135-139.

Hellmann, J.J., Byers, J.E., Bierwagen, B.G. and Dukes, J.S. 2008. Five potential consequences of climate change for invasive species. Conservation Biology 22: 534-543.

Lowe, S., Browne, M., Boudjelas, S. and De Poorter, M. 2000. 100 of the world's worst invasive alien species - a selection from the global invasive species database. 12.

Roura-Pascual, N., Hui, C., Ikeda, T., Leday, G., Richardson, D.M., Carpintera, S., Espadaler, X., Gomez, C., Guendard, B., Hartley, S., Krushelnycky, P., Lester, P.J., McGeoch, M.A., Menke, S.B., Pedersen, J.S., Pitt, J.P.W., Reyes, J., Sanders, N.J., Suarez, A.V., Touyama, Y., Ward, D., Ward, P.S. and Worner, S.P. 2011. Relative roles of climatic suitability and anthropogenic influence in determining the pattern of spread in a global invader. Proceedings of the National Academy of Sciences USA 108: 220-225.

Posted 19 May 2015