Abstract
Bioinvasions pose a major threat to global biodiversity. Correlative Ecological Niche Models (ENMs) can be a valuable tool to identify invaders and invasion sites. However, in cases when species are in non-equilibrium with their native environment (i.e. do not fill their niche), correlative approaches have limited power and invasions lead to shifts of the realized niche. In recent years, several new seaweed species have been reported in Antarctica. It is impossible to unequivocally identify which of these species are truly non-natives, however, here, we provide literature-based evidence that seaweed species have been introduced to Antarctica. Under this assumption, we reconstruct pre- and post-introduction niches of these species, calculate relative niche sizes and overlap between pre-Antarctic and Antarctic sites, and evaluate increase in niche size due to inclusion of Antarctic habitats. In seven species, the absolute occupied temperature range is dramatically enlarged, with minimum sea surface temperature (SST) being 2-5°C lower than in the pre-Antarctic ranges. In all species except one, summer SST is 5-20°C lower than in the pre-Antarctic ranges. As a result, several species’ niches increase dramatically. We hypothesize that species from the Southern Hemisphere do not cover their whole abiotically suitable range due to lack of settling substrate in cold-water regions while species from the Northern Hemisphere tend to fill their niches to a greater degree due to higher connectivity between tropic and polar regions along coastlines. Thus, while correlative ENMs for Northern Hemisphere species will probably be successful in predicting Antarctica as a suitable habitat, such models will likely be insufficient to do so for Southern Hemisphere species. From a precautionary standpoint, we argue that not only species from climatically matching regions pose an invasion threat for Antarctica, but that also species from other, climatically non-matching regions, might be potential invaders. In light of higher connectivity of the Antarctic continent with other continents this finding significantly increases invasion risk for Antarctica.
Highlights
Bioinvasions can have disastrous impacts on affected ecosystems and are recognized as a major threat to global biodiversity, ecosystem health, economy, and human health (Ruiz et al 1997, Casas et al 2004, Raffo et al 2009, Vilà et al 2010)
Realized niches can be extended during invasions (Atwater et al 2018, Cárdenas et al 2020) when species are in non-equilibrium with their native environment and originally unavailable niche space becomes accessible
Except for one species (D. decumbens), all species have well-documented distributions throughout other climatic zones in the Northern and/or Southern Hemisphere(s) (Fig. 2) and we categorized them based on their pre-Antarctic distributions: Category I contains five species distributed throughout polar to warm‐temperate or polar to tropical regions, respectively: B. minima, M. grevillei, P. fascia, U. compressa and U. intestinalis
Summary
Bioinvasions can have disastrous impacts on affected ecosystems and are recognized as a major threat to global biodiversity, ecosystem health, economy, and human health (Ruiz et al 1997, Casas et al 2004, Raffo et al 2009, Vilà et al 2010). Ecological niche models (ENM) can help predict the invasive potential of alien species and identify the geographic space at risk of invasion (Guisan and Thuiller 2005, Peterson 2005, Jiménez-Valverde et al 2011) Such models make estimations of a species’ realized niche [the occupied multidimensional space, which, in contrast to the fundamental niche, can be limited by other factors, (Hutchinson 1957)] based on correlations between distributional and environmental data. This information can be used to identify suitable but unoccupied geographic space. We evaluated the potential for successful introduction in accordance with the publication by Nyberg and Wallentinus (2005) and assigned the following potentials to the species based on species
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
