Mountain roads shift native and non‐native plant species' ranges

Abstract

Roads are known to act as corridors for dispersal of plant species. With their variable microclimate, role as corridors for species movement and reoccurring disturbance events, they show several characteristics that might influence range dynamics of both native and non‐native species. Previous research on plant species ranges in mountains however seldom included the effects of roads. To study how ranges of native and non‐native species differ between roads and adjacent vegetation, we used a global dataset of plant species composition along mountain roads. We compared average elevation and range width of species, and used generalized linear mixed models (GLMMs) to compile their range optimum and amplitude. We then explored differences between roadside and adjacent plots based on a species’ origin (native vs non‐native) and nitrogen and temperature affinity. Most non‐native species had on average higher elevational ranges and broader amplitudes in roadsides. Higher optima for non‐native species were associated with high nitrogen and temperature affinity. While lowland native species showed patterns comparable to those in non‐native species, highland native species had significantly lower elevational ranges in roadsides compared to the adjacent vegetation. We conclude that roadsides indeed change the elevational ranges of a variety of species. These changes are not limited to the expansion of non‐native species along mountain roads, but also include both upward and downward changes in ranges of native species. Roadsides may thus facilitate upward range shifts, for instance related to climate change, and they could serve as corridors to facilitate migration of alpine species between adjacent high‐elevation areas. We recommend including the effects of mountain roads in species distribution models to fine‐tune the predictions of range changes in a warming climate.

Plant community responses to environmentally friendly piste management in northeast Iran

“…Snow management in the piste might be the reason for this observation (Allegrezza et al, ). In our opinion, two important scenarios can be inferred from this observation; first, disturbances (e.g., overgrazing) can worsen the effects of climate change on the invasion of low‐elevation plants to alpine elevations (Lembrechts et al, ); second, in spite of the habitat degrading effects of pistes, these areas can be used for the alleviation of the climate change effects on the species distribution at the landscape scale.…”

“…Land-use changes and grazing are the main drivers for habitat degradation in the mountainous ecosystems (Bhatta, Grytnes, & Vetaas, 2018;Lembrechts et al, 2017;Li, Fassnacht, Storch, & Bürgi, 2017;Lu et al, 2017;Pauchard et al, 2009). Furthermore, climate change and invasion of lower-elevation plants threaten established plant communities of these areas (Walther et al, 2002).…”

Toward an improved conceptual understanding of North American tree species distributions

“…Human land use may also promote upslope range shifts by providing microrefugial habitats that allow species to establish above natural distribution limits, such as has been observed along mountain roads (Lembrechts et al. ).…”

Microclimate variability in alpine ecosystems as stepping stones for non‐native plant establishment above their current elevational limit

“…Studies of plant invasions in mountains are mostly observational and tend to focus on patterns of non-native species richness and the dynamics of spread along elevation gradients, but these studies often overlook the alpine and nival extremes of the gradient (Seipel et al 2012, Lembrechts et al 2017a). Much less is therefore known about the potential of non-native plants to establish there (Alexander et al 2016): does the prevailing harsh climate in alpine environments represent an inherent resistance to invasion as often assumed, or has anthropogenic pressure not yet reached these areas and is invasion just a matter of time (Pauchard et al 2009)?…”