Are species more harmful in their native, neonative or alien range? Insights from a global analysis of bark beetles

Abstract

Aim: Anthropogenic environmental modifications such as climate or land-use change are causing species to move on their own beyond their native ranges. As this phenomenon will increase in the near future, it is crucial to determine whether rangeexpanding species, or neonatives, are more or less likely than native and alien species to impact their recipient ecosystems. Here, we compared impact magnitudes of bark beetle species from their native, neonative and alien ranges, simultaneously. Location: Global. Methods:We formulated four general scenarios about the magnitude of environmental impacts in different ranges (native, neonative and alien) based on hypotheses commonly used in invasion biology. We tested these scenarios globally on Dendroctonus bark beetles, asking whether they have the most harmful impacts in their native, neonative or alien ranges. Impacts reported in the literature were assessed with the IUCN Environmental Impact Classification for Alien Taxa (EICAT). Results:We found that bark beetles cause the most harmful impacts in their native ranges, followed by the neonative ranges, while impacts in their alien ranges are the lowest. This indicates that the more dissimilar the environment is from that in the native range, the lower the probability of high-impact magnitudes. Our results align with several non-exclusive hypotheses, e.g. pre-adaptation and habitat filtering, while they do not support others, e.g. enemy release or Darwin's naturalization. The results are also in contrast with previous studies on vertebrates and plants, which found no or mixed differences in impact magnitudes with biogeographic origin.Main conclusions: Our analysis suggests that bark beetles, like other species that are keystone and abundant in their native ranges, have generally lower impacts when introduced to novel environments due to biotic resistance or lack of pre-adaptation.Research and management implications regarding the impacts of neonative and alien populations are also discussed.

Origin matters? Comparing impacts of native and introduced ungulates in European protected areas

“…They found that origin was not a strong predictor of environmental impacts for bamboos. Forgione et al (2022) also used EICAT to evaluate the impact of 20 species of bark beetles (Insecta: Curculionidae) at a global scale. Their analysis suggests that bark beetles, like other species that are keystone and abundant in their native ranges, have generally lower impacts when introduced to novel environments due to biotic resistance or lack of pre-adaptation.…”

“…Based on this information, we conducted the first comparison of the negative impact of native and introduced populations of a taxonomic group of terrestrial vertebrates using EICAT, and we tested the hypothesis that introduced species have greater environmental impacts than native species, that is, that origin status influence the magnitude of environmental impact. We found only three recent previous studies that used this score system to perform this type of comparison and test this hypothesis: 1) Canavan et al (2019) with bamboos (Poaceae: Bambusoideae) species, 2) Henry and Sorte (2022) with 39 marine species (including plants, invertebrates, fish, a protist and a bird) and 3) Forgione et al (2022) with bark beetles (genus Dendroctonus).…”

“…(2019) with bamboos (Poaceae: Bambusoideae) species, 2) Henry and Sorte (2022) with 39 marine species (including plants, invertebrates, fish, a protist and a bird) and 3) Forgione et al. (2022) with bark beetles (genus Dendroctonus).…”

Evolutionary history of host trees amplifies the dilution effect of biodiversity on forest pests

“…Maladaptive hyper-virulence, for example, whereby pests quickly kill hosts, could theoretically increase pest prevalence in the short term but reduce pest prevalence in the long term, as available living hosts become rarer. While non-native pests may be most likely to be out of adaptive equilibrium with their hosts, there is as yet only limited evidence that they have systematically higher impacts on hosts than native pests [43,44].…”

Taming the terminological tempest in invasion science

“…'assisted migration' (cf. Hällfors et al, 2014;Pereyra, 2020)], these populations can cause ecological disruptions once established (Forgione, Bacher & Vimercati, 2022), but might simultaneously require protection given threats in their native ranges (Essl et al, 2021b;Forgione et al, 2022). The conundrum arises from the origin of environmental or climatic changes, which might also be considered anthropogenic, thereby blurring the distinction between 'neonative' and 'non-native'.…”