A global assessment of climatic niche shifts and human influence in insect invasions

Abstract

Aim Non‐native invasive insects have major impacts on ecosystem function, agricultural production and human health. To predict the geographical distributions of these species, correlative ecological niche models (ENMs) are typically used. Such methods rely on assumptions of niche conservatism, although there is increasing evidence that many species undergo niche shifts during invasions. The magnitude and direction of niche shifts, however, is likely to vary within and between taxonomic groups, highlighting that an assessment of potential niche shifts in such insects is required. Location Global. Time period Current. Major taxa studied Insects. Methods We compile a novel database of 22 globally invasive, non‐native insect species and test for niche expansion and unfilling across this group. We examine if factors such as the native range size, poleward shifts and human influence may be associated with observed niche changes. Finally, we construct ENMs and examine the reliability of their predictions in light of our niche shift results. Results Niche expansion was apparent in 12 of the 22 species, suggesting that altered species–climate relationships during invasion is common for this group. Likewise, niche unfilling occurred in 15 of the species. Increasing human disturbance (combining human population, transport networks and land use) explained 40% of observed niche expansions and 54% of incidents of niche unfilling. Niche metrics and ENM performance were sensitive to the choice of background extents. Main conclusions Many non‐native insects expand into new climates in their invasive ranges. The prevalence of niche unfilling across this group suggests climate disequilibrium and the potential for further range expansion. Non‐native invasive insects tend to invade areas with similar human disturbance to their native range, and habitat accessibility appears important for these species to achieve their full invasion range potential. Ideally, ENMs should not be used in isolation for this group, but should be coupled with other methods or experiments to test for potential niche change.

Zika: Probabilidad de establecimiento de su vector, Aedes aegypti, en Chile

“…Por lo anterior, el presente estudio constituye un antecedente que sugiere fuertemente que A. aegypti podría colonizar y establecerse en ciertos lugares de Chile continental. Las predicciones del modelo presentado aquí pueden considerarse conservadoras en términos de la distribución potencial predicha para el insecto, ya que, en general, las especies invasoras pueden ampliar su nicho ecológico en los lugares colonizados, colonizando zonas mayores a las predichas por la proyección 17,30,31 . En este sentido, recomendamos enfatizar las medidas de prevención, monitoreo y control del mosquito en las áreas definidas por el modelo.…”

Climate, human influence and the distribution limits of the invasive European earwig, Forficula auricularia, in Australia

“…They are part of the BIOCLIM package and are widely employed in species distribution modelling. The scale of 10′ (roughly 20 km 2 at the equator) is also relevant to the model construction and transferability for broadly distributed species between large, distinct, geographical regions . To address different resolutions of reported coordinates and repeated local observations across datasets (and provide data at the same resolution as the predictor variables) we rescaled all observations to this grid cell level, which resulted in 3304 unique points, 162 in Australia.…”

Predicting the success of an invader: Niche shift versus niche conservatism

“…Niche conservatism during the invasion process of Ae. albopictus has been examined previously (Cunze et al, 2018;Hill et al, 2017;Medley, 2010). These studies suggested that invasive populations' niche ranges (Europe, North America, South America, Africa) differ from those of native Asian populations (Cunze et al, 2018;Medley, 2010).…”

“…albopictus global distribution range, but they primarily aimed at evaluating the potential contemporary and future distributions. Studies evaluating the niche conservatism hypothesis revealed that invaded niches differ from those of native populations (Cunze, Kochmann, Koch, & Klimpel, 2018;Hill, Gallardo, & Terblanche, 2017;Medley, 2010). These differences were either explained by niche expansion supporting niche shift (Hill et al, 2017) or by niche unfilling supporting niche conservatism (Cunze et al, 2018).…”

“…Studies evaluating the niche conservatism hypothesis revealed that invaded niches differ from those of native populations (Cunze, Kochmann, Koch, & Klimpel, 2018;Hill, Gallardo, & Terblanche, 2017;Medley, 2010). These differences were either explained by niche expansion supporting niche shift (Hill et al, 2017) or by niche unfilling supporting niche conservatism (Cunze et al, 2018). These studies compared invaded range niches to those of the entire Asian native range (Cunze et al, 2018;Medley, 2010), but assessing the adaptive potential of introduced populations requires having a good knowledge of their precise source.…”