Will climate change increase the risk of plant invasions into mountains?

Abstract

1Mountain ecosystems have been less adversely affected by invasions of non-native plants than 2 most other ecosystems, partially because most invasive plants in the lowlands are limited by 3 climate and cannot grow under harsher high-elevation conditions. However, with ongoing 4 climate change, invasive species may rapidly move upwards and threaten mid, and then high 5 elevation mountain ecosystems. We evaluated this threat by modeling the current and future 6 habitat suitability for 48 invasive plant species in Switzerland and New South Wales, Australia. 7Both regions had contrasting climate interactions with elevation, resulting in possible different 8 responses of species distributions to climate change. Using a species distribution modeling 9 approach that combines data from two spatial scales, we built high-resolution species distribution 10 models (≤ 250 m) that account for the global climatic niche of species and also finer variables 11 depicting local climate and disturbances. We found that different environmental drivers limit the 12 elevation range of invasive species in each of the two regions, leading to region-specific species 13 responses to climate change. The optimal suitability for plant invaders is predicted to markedly 14 shift from the lowland to the montane or subalpine zone in Switzerland, whereas the upward shift 15 is far less pronounced in New South Wales where montane and subalpine elevations are already 16 suitable. The results suggest that species most likely to invade high elevations in Switzerland 17 will be cold-tolerant, whereas species with an affinity to moist soils are most likely to invade 18 higher elevations in Australia. Other plant traits were only marginally associated with elevation 19limits. These results demonstrate that a more systematic consideration of future distributions of 20 invasive species is required in conservation plans of not yet invaded mountainous ecosystems. 21

A global analysis of elevational distribution of non‐native versus native plants

“…The vertical spread of non‐native species, as investigations of Hawaii and New Zealand suggest might occur, and the facilitation by climate change (warming) of upslope range extensions of non‐native species (Pauchard et al., ) are likely to pose a significant ecological threat to native species at higher elevations. Although, with warming climates, both native and non‐native species are expected to shift to higher elevations in tracking optimal temperatures (Dainese et al., ; Petitpierre et al., ), native species on mountaintops are likely to be most at risk from local extirpation because no other habitat is available to them (Hellmann, Byers, Bierwagen, & Dukes, ; Nogues‐Bravo et al., ). While there is some debate about the outcomes of competition among native and non‐native species (e.g.…”

Non-native and native organisms moving into high elevation and high latitude ecosystems in an era of climate change: new challenges for ecology and conservation

“…There are also important biases in research efforts, with the tropics and the coldest places on Earth far less studied than temperate biomes, and many more published case studies reporting range shifts towards higher latitudes for animals than for plants (Lenoir & Svenning 2015). Methodological shortfalls are also present with a strong bias towards reporting unidimensional and unidirectional range shifts, while multi-facetted assessments of species range shifts are strongly needed (Lenoir & Svenning 2015, Petitpierre et al 2015. For instance, terrestrial native organisms are not only shifting their ranges towards higher latitudes or elevations as is usually reported, but they are also shifting ranges in unexpected directions (e.g.…”

“…Non-native plant invasions at high elevation have so far been limited by reduced human activity at high elevation coupled with a climatic filter (Alexander et al 2011, Petitpierre et al 2015. Roads and other anthropogenic environments have been the main corridors for species spread into mountain habitats.…”

“…However, climate warming, land use change (e.g. expansion of tourism and resource extraction), and associated increased global connectivity all increase the risk of biological invasions in these cold environments (Pauchard et al 2009;Convey 2011, Petitpierre et al 2015. These changes facilitate the introduction and establishment of new species that may alter the composition and dominance patterns of existing communities of microorganisms, plants and animals (cf.…”

Sensitivity to environmental change of the treeline ecotone and its associated biodiversity in European mountains

“…climate change (Hofgaard 1999, Alexander et al 2015. The presence of potentially invasive species make any prediction difficult or impossible (Mooney & Hofgaard 1999, Petitpierre et al 2016. During the last 50 to 100 yr, summer farming practice has become strongly reduced both in northern and more southern European mountain areas (Bryn & Daugstad 2001, Tasser & Tappeiner 2002, Camarero & Gutiérrez 2007, Chauchard et al 2007, Tasser et al 2007, Batllori & Gutiérrez 2008, Amez tegui et al 2010, Treml et al 2016.…”