From introduction to the establishment of alien species: bioclimatic differences between presence and reproduction localities in the slider turtle

Abstract

Aim Understanding the factors determining the transition from introduction of aliens to the establishment of invasive populations is a critical issue of the study of biological invasions, and has key implications for management. Differences in fitness among areas of introduction can define the zones where aliens become invasive. The American slider turtle Trachemys scripta has been introduced worldwide, and has negative effects on freshwater communities, but only a subset of introduced populations breed successfully. We used species distribution models to assess the factors influencing the slider distribution in Italy, by analysing bioclimatic features that can cause the transition from presence of feral adults to breeding populations. We also evaluated whether climate change might increase the future suitability for reproduction. Location Central and Northern Italy. Methods The distribution of slider turtle was obtained from the literature, unpublished reports and field surveys. We used Maxent to build bioclimatic models. Results Reproductive populations are associated to a clear bioclimatic envelope with warmer climate, more solar radiation and higher precipitations than populations where reproduction is not observed. Several Mediterranean areas currently have climatic features suitable for sliders. Scenarios of climate change predict the expansion of these areas. In the near future (2020), the proportion of populations in areas suitable for reproduction will dramatically increase. Main conclusion Our study shows that bioclimatic differences can determine the areas where aliens become invaders. Management should be focused to these source areas. However, climate change can increase fitness in the future, and therefore the interactions between climate change and fitness can boost the invasiveness of this alien species.

Knowing the past to predict the future: land‐use change and the distribution of invasive bullfrogs

“…Habitat suitability models are often used for this task, with applications in risk assessment or in control strategies (e.g., Ward, 2007;Evangelista et al, 2008;Nielsen et al, 2008;Ficetola et al, 2009). However, long term historical data are seldom available (Loo et al, 2007;Vallecio et al, 2009), and it is therefore difficult to evaluate whether model predictions correspond to the actual invasion dynamics.…”

“…Temporal change of climate is probably the dynamic feature most often integrated in models of biological invasions. Climate, in fact, is a major driver of environmental suitability for AIS, thus many recent studies used scenarios of future climate to project species distribution model and to predict the areas that might become suitable for AIS in the future (Roura-Pascual et al, 2004;Beaumont et al, 2009;Ficetola et al, 2009).…”

Minimizing false‐negatives when predicting the potential distribution of an invasive species: a bioclimatic envelope for the red‐eared slider at global and regional scales

“…European pond turtles Emys orbicularis; (Lever, 2003)] disrupt food-webs by consuming aquatic vegetation, invertebrates and vertebrates (Ernst, Lovich & Barbour, 1994;Ligon, 2007;Prevot-Julliard et al, 2007) and negatively affect birdlife, for example by drowning eggs while basking in water-bird nests (ISSG, 2006). The RES is native to the Mississippi Valley area, USA, and has established wild populations in several countries, including Australia, Spain, France, Italy, Taiwan, Japan, Guam, among others outside of its native range in North America, (Ng, Chou & Lam, 1993;Chen & Lue, 1998;Bomford, 2003;Lever, 2003;ISSG, 2004;Ficetola, Thuiller & Padoa-Schioppa, 2009). …”

“…As it can be difficult to infer soil temperatures from air temperature data (Hartley & Lester, 2003), and given that the metabolic activity of developing eggs may raise the surrounding soil temperature (Burger, 1976), further research on potential nest temperatures in New Zealand is required. Previous attempts to model areas of climatic suitability for RES at a regional scale have included additional variables such as amount of solar radiation and 'human footprint', a measure of human influence on the global surface (Ficetola et al, 2009). These factors are relevant, as RES are dependent on environmental warmth to regulate body temperature and for egg incubation, and released pets are often concentrated in areas of high human density.…”

Xenodiversity in a hot-spot of herpetological endemism: first records of Trachemys scripta, Ameiurus melas and Carassius auratus in a circum-Sardinian island

“…Trachemys scripta being highly invasive and an active predator (27), has a heavy impact on fish and amphibians species, in particular on those species that lay eggs in shallow waters (28; L. Luiselli, pers. comm.).…”