A Quantitative Climate-Match Score for Risk-Assessment Screening of Reptile and Amphibian Introductions

Centre for Invasion Biology (CIB), Department of Botany & Zoology, Stellenbosch University, Matieland, Stellenbosch, Western Cape 7602, South Africa.
Environmental Management (Impact Factor: 1.72). 08/2009; 44(3):590-607. DOI: 10.1007/s00267-009-9311-y
Source: PubMed


Assessing climatic suitability provides a good preliminary estimate of the invasive potential of a species to inform risk assessment. We examined two approaches for bioclimatic modeling for 67 reptile and amphibian species introduced to California and Florida. First, we modeled the worldwide distribution of the biomes found in the introduced range to highlight similar areas worldwide from which invaders might arise. Second, we modeled potentially suitable environments for species based on climatic factors in their native ranges, using three sources of distribution data. Performance of the three datasets and both approaches were compared for each species. Climate match was positively correlated with species establishment success (maximum predicted suitability in the introduced range was more strongly correlated with establishment success than mean suitability). Data assembled from the Global Amphibian Assessment through NatureServe provided the most accurate models for amphibians, while ecoregion data compiled by the World Wide Fund for Nature yielded models which described reptile climatic suitability better than available point-locality data. We present three methods of assigning a climate-match score for use in risk assessment using both the mean and maximum climatic suitabilities. Managers may choose to use different methods depending on the stringency of the assessment and the available data, facilitating higher resolution and accuracy for herpetofaunal risk assessment. Climate-matching has inherent limitations and other factors pertaining to ecological interactions and life-history traits must also be considered for thorough risk assessment.


Available from: Nicola Jane Van Wilgen
  • Source
    • "The models of Pyron et al. (2008), Rodda et al. (2009), and Van Wilgen et al. (2009) "
    [Show abstract] [Hide abstract]
    ABSTRACT: Range expansion potential is an important consideration for prioritizing management actions against an invasive species. Understanding the potential for range expansion by invasive reptiles such as the Burmese python can be challenging, because the lack of knowledge on fundamental physiological and behavioral constraints initially forces reliance on modeling to predict hypothetical invasive range potential. Hypothetical predictions for Burmese python range limits in the USA have been highly divergent, from only extreme South Florida and the extreme southern Gulf edge of Texas to a broad swath over the southern third of the continental USA. Empirical observations on python thermal tolerances and behavioral abilities to cope with more temperate temperatures became evident during a cold spell in December 2009-January 2010. We review and highlight important considerations for improving invasive range estimation methodology, deciding between competing range predictions, and the importance of having, and applying, empirical data to aid in decision making.
    Environmental Science and Pollution Research 06/2014; 21(20). DOI:10.1007/s11356-014-3173-4 · 2.83 Impact Factor
  • Source
    • "Overall, our findings suggest that the factors promoting establishment success among alien reptiles and amphibians are not necessarily the same as those promoting spread. For example, previous studies have found that climate match (Bomford et al. 2009; van Wilgen et al. 2009; Fujisaki et al. 2010; van Wilgen & Richardson 2012), native geographic range size (Allen et al. 2013; but see counter-example in Bomford et al. 2009) and introduction pathway (Rago et al. 2012) predict the probability of successful establishment, but these factors generally had negligible effects on spread rates in our analyses. Earlier studies of herpetofauna (Allen et al. 2013), mammals (Forsyth et al. 2004) and birds (Duncan et al. 2001) found that smaller species colonise larger geographic ranges. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Understanding the factors that determine rates of range expansion is not only crucial for developing risk assessment schemes and management strategies for invasive species, but also provides important insight into the ability of species to disperse in response to climate change. However, there is little knowledge on why some invasions spread faster than others at large spatiotemporal scales. Here, we examine the effects of human activities, species traits and characteristics of the invaded range on spread rates using a global sample of alien reptile and amphibian introductions. We show that spread rates vary remarkably among invaded locations within a species, and differ across biogeographical realms. Spread rates are positively related to the richness of native congeneric species and human-assisted dispersal in the invaded range but are negatively correlated with topographic heterogeneity. Our findings highlight the importance of environmental characteristics and human-assisted dispersal in developing robust frameworks for predicting species' range shifts.
    Ecology Letters 04/2014; 17(7). DOI:10.1111/ele.12286 · 10.69 Impact Factor
  • Source
    • "Cooper et al., 2008; Finer et al., 2008; van Wilgen et al., 2009; Lawler et al., 2010; Becker & Zamudio, 2011; Sandel et al., 2011; Hof et al., 2012), including analyses performed on fine spatial scales (e.g. Finer et al., 2008; van Wilgen et al., 2009; Becker & Zamudio, 2011). The maps may be affected by multiple sources of error, such as incomplete information on some species or in some areas, limited spatial resolution, and errors when digitizing the distribution ranges, which may influence the output of analyses based on these maps (Hurlbert & Jetz, 2007; Foody, 2011; Rocchini et al., 2011; Cant u-Salazar & Gaston, 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Aim Maps of species ranges are among the most frequently used distribution data in biodiversity studies. As with any biological data, range maps have some level of measurement error, but this error is rarely quantified. We assessed the error associated with amphibian range maps by comparing them with point locality data. Location Global. Methods The maps published by the Global Amphibian Assessment were assessed against two data sets of species point localities: the Global Biodiversity Information Facility (GBIF), and a refined data set including recently published, high-quality presence data from both GBIF and other sources. Range fit was measured as the proportion of presence records falling within the range polygon(s) for each species. Results Using the high-quality point data provided better fit measures than using the raw GBIF data. Range fit was highly variable among continents, being highest for North American and European species (a fit of 84–94%), and lowest for Asian and South American species (a fit of 57–64%). At the global scale, 95% of amphibian point records were inside the ranges published in maps, or within 31 km of the range edge. However, differences among conti-nents were striking, and more points were found far from range edges for South American and Asian species. Main conclusions The Global Amphibian Assessment range maps represent the known distribution of most amphibians well; this study provides measures of accuracy that can be useful for future research using amphibian maps as baseline data. Nevertheless, there is a need for greater investment in the contin-uous updating and improvement of maps, particularly in the megadiverse areas of tropical Asia and South America.
Show more