Geographical potential of Argentine ants ( Linepithema humile Mayr) in the face of global climate change

Abstract

Determining the spread and potential geographical distribution of invasive species is integral to making invasion biology a predictive science. We assembled a dataset of over 1000 occurrences of the Argentine ant (Linepithema humile), one of the world's worst invasive alien species. Native to central South America, Argentine ants are now found in many Mediterranean and subtropical climates around the world. We used this dataset to assess the species' potential geographical and ecological distribution, and to examine changes in its distributional potential associated with global climate change, using techniques for ecological niche modelling. Models developed were highly predictive of the species' overall range, including both the native distributional area and invaded areas worldwide. Despite its already widespread occurrence, L. humile has potential for further spread, with tropical coastal Africa and southeast Asia apparently vulnerable to invasion. Projecting ecological niche models onto four general circulation model scenarios of future (2050s) climates provided scenarios of the species' potential for distributional expansion with warming climates: generally, the species was predicted to retract its range in tropical regions, but to expand at higher latitude areas.

Uses and Requirements of Ecological Niche Models and Related Distributional Models

“…These projections, under assumptions made fairly explicit, provide hypotheses of species' potential geographic distributions and how they will change over the next few decades of evolving world climates, and this field has now seen extensive activity Berry et al 2002;Carey and Brown 1994;Erasmus et al 2002;Gottfried et al 1999;Huntley et al 1995;Kadmon and Heller 1998;Malanson et al 1992;Pearson and Dawson 2003;Pearson et al 2002;Peterson 2003b;Peterson et al 2004b;Peterson et al 2002;Peterson and Shaw 2003;Peterson et al 2005b;Porter et al 2000;Price 2000;Roura-Pascual et al 2005;Sykes et al 1996;Thuiller et al 2005a), including retro-projections aimed at reconstructing distributions in the Pleistocene (Hilbert et al 2004;Hugall et al 2002;Martínez-Meyer and Peterson 2006;Martínez-Meyer et al 2004a). The complexities of these projections, however, are only beginning to be appreciated, given species' responses to other factors such as atmospheric gas composition .…”

Yet another alien: a second species of Lepisiota spreading across the Canary Islands, Spain (Hymenoptera: Formicidae)

“…Invasive behaviours are hard to predict a priori as they depend on a high number of local factors, and are also expected to vary in response to the ongoing environmental changes (e.g. Roura-Pascual et al 2004). Therefore, the presence of such remarkably high numbers of both endemic and introduced ants species raises obvious concerns in terms of conservation, especially as the latter have continued to increase and spread across the islands during the last decades (Espadaler & Bernal 2003;Högmo 2003;Espadaler 2007;Espadaler & Fernandez 2014).…”

Opening the climate envelope reveals no macroscale associations with climate in European birds

“…Ideally, the predictions of climate envelope models would be verified on an entirely independent dataset (14,15) and some attempts have been made at this, both by prediction of the potential distribution of introduced species in new continents (16) or through backward prediction (hindcasting) of prehistoric distributions reconstructed from the fossil record (17). Unfortunately, truly independent data are generally unavailable, so the usefulness of a climate envelope model is typically measured by how well it fits a subset of the current species distribution reserved for evaluation (8).…”