Relative roles of climatic suitability and anthropogenic influence in determining the pattern of spread in a global invader

Abstract

Because invasive species threaten the integrity of natural ecosystems, a major goal in ecology is to develop predictive models to determine which species may become widespread and where they may invade. Indeed, considerable progress has been made in understanding the factors that influence the local pattern of spread for specific invaders and the factors that are correlated with the number of introduced species that have become established in a given region. However, few studies have examined the relative importance of multiple drivers of invasion success for widespread species at global scales. Here, we use a dataset of >5,000 presence/absence records to examine the interplay between climatic suitability, biotic resistance by native taxa, humanaided dispersal, and human modification of habitats, in shaping the distribution of one of the world's most notorious invasive species, the Argentine ant (Linepithema humile). Climatic suitability and the extent of human modification of habitats are primarily responsible for the distribution of this global invader. However, we also found some evidence for biotic resistance by native communities. Somewhat surprisingly, and despite the often cited importance of propagule pressure as a crucial driver of invasions, metrics of the magnitude of international traded commodities among countries were not related to global distribution patterns. Together, our analyses on the global-scale distribution of this invasive species provide strong evidence for the interplay of biotic and abiotic determinants of spread and also highlight the challenges of limiting the spread and subsequent impact of highly invasive species.iological invasions can disrupt ecosystem functioning, homogenize biota, and threaten global diversity (1). To mitigate the often dramatic consequences of many invasive species on native ecosystems and the services they provide, a fundamental goal for conservation biology is to be able to predict which species will invade and which areas are most vulnerable to their invasion (2). Despite considerable efforts at both local and regional scales to elucidate the relative roles of biotic and abiotic conditions on the spread and impact of introduced species (e.g., refs. 3-6), understanding which factors limit the global distribution of species is still a largely unanswered question (7).One approach that has been relatively successful is to relate the number of invasive species established in a given area to factors that describe the region. For example, Pyšek et al. recently used up-to-date information on the presence of alien species from a variety of taxa to identify general predictors of the level of invasion (e.g., number of established species) across Europe (8). They found an overwhelming influence of anthropogenic factors (i.e., wealth and demography) in determining the distribution of alien species. Few studies consider the influence of environmental and human-mediated factors in shaping the global distribution of invasive species (8, 9), particularly for single species...

The widespread collapse of an invasive species: Argentine ants ( Linepithema humile ) in New Zealand

“…First observed in New Zealand in Auckland during 1990, the species has since spread widely around the country assisted by human-mediated dispersal [7]. The dates and locations of newly observed infestations have been recorded for many populations [5], which typically range in size from a few to several hundred hectares. Environmental variables, such as temperature and rainfall have previously been suggested to help limit the distribution of this ant [5,8].…”

“…The dates and locations of newly observed infestations have been recorded for many populations [5], which typically range in size from a few to several hundred hectares. Environmental variables, such as temperature and rainfall have previously been suggested to help limit the distribution of this ant [5,8]. Consequently, this invasive species is expected to expand its range with climate change, particularly, in regions of higher latitude such as New Zealand [9].…”

“…Originally from South America, this ant is known to invade sub-tropical and temperate regions and is established on six continents [5]. Introduced populations form high-density, widespread, highly aggressive, unicolonial populations and can deleteriously influence native communities [6].…”

Traits related to biological invasion: A note on the applicability of risk assessment tools across taxa

“…Invasive insects have more extreme high and low humidity tolerances than natives (Wuellner and Saunder 2003) E, O Elevation Invasive insects prefer low elevation, whereas natives prefer high elevation (Human et al 1998, Arndt and Perner 2008, Fitzgerald and Gordon 2012 O Climate matching Invaded range must be climatically suitable for the invasive insect (Simberloff 1989, Holway 1998, Koch et al 2006, Gray et al 2008, Roura-Pascual et al 2011, Sun et al 2013 A Invasive insects more abundant in cool, dry areas, whereas native insects are more abundant in warm, humid areas (Parkash et al 2014);…”

Stable isotopes reveal an invasive plant contributes more than native sources to anuran larvae diets

“…The impact of invaders to wetlands is vigorously debated. Many studies argue that invasions have purely negative impacts on wetlands by reducing biodiversity, causing shifts in organismal consumption patterns, and altering the availability of nutrients (Ehrenfeld et al 2003;Yakimowski et al 2005;Roura-Pascual et al 2011). Alternatively, a few studies suggest that invasions have a small or no impact on ecosystems and that it benefits from the added nutrients (Vil a et al 2011).…”