The grass may not always be greener: projected reductions in climatic suitability for exotic grasses under future climates in Australia

Abstract

Climate change presents a new challenge for the management of invasive exotic species that threaten both biodiversity and agricultural productivity. The invasion of exotic perennial grasses throughout the globe is particularly problematic given their impacts on a broad range of native plant communities and livelihoods. As the climate continues to change, pre-emptive long-term management strategies for exotic grasses will become increasingly important. Using species distribution modelling we investigated potential changes to the location of climatically suitable habitat for some exotic perennial grass species currently in Australia, under a range of future climate scenarios for the decade centred around 2050. We focus on eleven species shortlisted or declared as the Weeds of National Significance or Alert List species in Australia, which have also become successful invaders in other parts of the world. Our results indicate that the extent of climatically suitable habitat available for all of the exotic grasses modelled is projected to decrease under climate scenarios for 2050. This reduction is most severe for the three species of Needle Grass (genus Nassella) that currently have infestations in the south-east of the continent. Combined with information on other aspects of establishment risk (e.g. demographic rates, human-use, propagule pressure), predictions of reduced climatic suitability provide justification for re-assessing which weeds are prioritised for intensive management as the climate changes.

Out of the weeds? Reduced plant invasion risk with climate change in the continental United States

“…Hotspots of Biological Conservation 203 (2016) [306][307][308][309][310][311][312] plant invasion with current and future climate have been identified in Australia for nationally important invasive plants (Gallagher et al, 2013;O'Donnell et al, 2012), but there has been no comprehensive assessment of the invasion risk posed by plants to the continental U.S. under current and future climates. Invasion risk can have many definitions; this analysis focuses on the geography of invasion risk through invasive plant range characteristics (range infilling) and aggregated range metrics (species richness, invasion debt, and identification of hotspots).…”

Ecology and Management of Weeds in a Changing Climate

“…As with North America and Europe, such distributional changes (southward) have been documented for a number of weed species (Table 2.5) [22,28,29,83,84].…”

“…Parts of Oceana, particularly Australia and New Zealand, have also received considerable attention in this regard [28,29]. Economic development and weeds have also tended to go hand in hand, as illustrated by the widespread introductions of Eurasian weeds to North America [30].…”

“…Gallagher et al showed how 11 species of alien perennial grasses that were either shortlisted or listed as weed threats of national importance in Australia could undergo alterations in distribution with climate change [29]. As is seen worldwide, these grasses can have devastating impacts on crops and rangeland in Australia, even though most of these were deliberately introduced as forage grasses.…”

“…As is seen worldwide, these grasses can have devastating impacts on crops and rangeland in Australia, even though most of these were deliberately introduced as forage grasses. However, because these grasses are already near the edge of their climate optima in Australia, if temperatures along with drought conditions increase through climate change as predicted, these grasses may not be able to maintain their current extent [29]. For example, the range of Cortaderia selloana (J.A.…”