Climatic niche shifts in 815 introduced plant species affect their predicted distributions

Abstract

Aim Introduced species often occupy different climates in their introduced than their native range, but to what degree do such ‘climatic niche shifts’ interfere with our ability to predict invasions? Answering this question is crucial if we are to understand the threat invasive species pose to human and natural systems, especially given the ever increasing use of species distribution models as tools for invasive species risk assessment and management. Here we investigated the degree to which climatic niche shifts interfered with the transferability of native‐ and introduced‐range species distribution models. Location Our dataset consisted of c. 14 million occurrences distributed worldwide. Time period Occurrence data were collected from online repositories dating from c. 1600 with the vast majority being from the 20th century. Climatic data represent means between 1970 and 2000. Major taxa studied Our database represented 815 terrestrial plant species. Methods We used ordination to identify climatic niche shifts as species moved between continents. Next, we trained separate Maxent models using native‐ or introduced‐range occurrences, and projected those models into each species’ introduced range. We compared the ordination and Maxent models to determine whether niche shifts were associated with errors in Maxent predictions. Results Models trained on native‐range occurrences poorly predicted introduced‐range occurrences, and transferability was lowest in species with large climatic niche shifts. Directional shifts in species’ predicted geographic distributions mirrored their niche dynamics. This is concerning because native‐range data are often used to predict introduced‐range distributions. Main conclusions Our results highlight the importance of considering niche shifts when modelling the potential geographic distributions of introduced species, and cast doubt on the assumption that the climatic niche of a species can be transferred between native and invasive ranges.

Multiple invasion trajectories induce niche dynamics inconsistency and increase risk uncertainty of a plant invader

“…Such a change in high-risk areas indicates that the niche shift of M. micrantha could cast uncertainty on its ENM-based risk assessment due to the colonization of novel climatic conditions in the IRSWC. These findings agree with the study by Atwater and Barney (2021) who showed that niche shifts greatly matter when modeling ecological niches of introduced species because they could significantly reduce the transferability of native-and introduced-range ENMs. Additionally, our results suggest the existence of a geographic separation of ranges and ongoing population expansion of M. micrantha in China, while Yang et al (2017) reported genetic differentiation of M. micrantha populations in the IRSWC and IRSC.…”

“…Colonization of new regions outside of a species native range induced by human activities is largely linked to shifts in the species realized climatic niches (Atwater et al, 2018). Lacking awareness of niche dynamics of IAS impairs niche‐based predictions of invasion risk assessments (Atwater & Barney, 2021). Understanding niche dynamics of IAS and resulting risk uncertainties is one of the fundamental bases in mitigating invasion impacts and preventing invasions to new environments.…”

Evidence of the niche expansion of crofton weed following invasion in China

“…Likewise, the climatic niches of Ligustrum lucidum W.T.Aiton differed between its invasive and native zones (Dreyer et al, 2019). Furthermore, the climatic niche of 65% out of 815 introduced terrestrial plants was markedly shifted (Zachariah Atwater & Barney, 2021). Taken together, these findings indicate that IAPs may undergo niche shifts upon successfully invading new zones.…”

Evaluating niche changes during invasion with seasonal models in Capsella bursa‐pastoris

“…Typically, suitable habitat is forecast using the current distribution of a species and associated measured environmental variables (Pearman et al, 2008; Lee‐Yaw et al, 2022). However, meta‐analyses have found that the realized species niches often shift during invasion (Fitzpatrick et al, 2007; Early and Sax, 2014; Atwater et al, 2018; Liu et al, 2020; Atwater and Barney, 2021; Nguyen et al, 2022). Shifts in the realized niche could represent evolution or changes in the available environment (Bates and Bertelsmeier, 2021).…”

“…In this study, we investigate potential niche shifts during invasion by comparing year‐long and monthly Ecological Niche Models (ENM) in the native and non‐native range of C. bursa‐pastoris . These models are commonly used to study niche differences between native and non‐native populations (Liu et al, 2020; Atwater and Barney, 2021; Nguyen et al, 2022). We use the monthly models to investigate whether change in the timing of the seasonal niche is due to a shift in seasonal timing or a shift in the climatic conditions that predict occurrence.…”