Open AccessHow can knowledge of the climate niche inform the weed risk assessment process? A case study of C hrysanthemoides monilifera in A ustralia
Author(s) -
Beaumont Linda J.,
Gallagher Rachael V.,
Leishman Michelle R.,
Hughes Lesley,
Downey Paul O.
Publication year - 2014
Publication title -
diversity and distributions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.918
H-Index - 118
eISSN - 1472-4642
pISSN - 1366-9516
DOI - 10.1111/ddi.12190
Subject(s) - subspecies , ecological niche , niche , alien , ecology , invasive species , range (aeronautics) , habitat , geography , introduced species , alien species , environmental niche modelling , climate change , biology , population , materials science , demography , sociology , composite material , census
Aim Climate change and the ability of alien populations to realize different climatic niches compared to native populations pose challenges for pre‐empting invasion risk. These issues are not addressed in W eed R isk A ssessments ( WRA s), which have been developed to identify potentially invasive species and prevent their importation. C hrysanthemoides monilifera , native to Southern Africa, has two subspecies invasive in Australia, which has led to an importation ban on all six subspecies. We assess whether the two invasive subspecies occupy different realized climatic niches, compared with native populations, and the climatic suitability of Australia for all subspecies under current and future climate scenarios. Location S outhern A frica and A ustralia Methods Realized climatic niches of native and alien populations of two invasive subspecies ( B itou B ush and B oneseed) were compared using niche identity tests. The distribution of climatically suitable habitat within Australia for all subspecies was modelled using M ax E nt, under current and future climate scenarios. For invasive subspecies, models were calibrated using (1) native or (2) alien range data. Results Realized climatic niches of native and alien populations are not identical, with some alien populations of B oneseed occupying climatic niches absent from Southern A frica. As such, M ax E nt models for B oneseed based on native range data failed to classify one‐third of Australian populations as inhabiting suitable climate. Main Conclusions We validate the A ustralian decision to ban all subspecies by showing that climatically suitable habitat in Australia for non‐introduced subspecies exceeds that of introduced subspecies, under current and future climates. Niche shifts and climate change alter estimates of invasion risks, and this may reduce efficacy of current WRA s. We call for greater dialogue to identify and standardize a comprehensive system for incorporating these challenging issues into WRA systems to ensure that they remain effective in reducing the weed risk into the future.