INVESTIGADORES
LESCANO Maria Natalia
artículos
Título:
Synergy between roads and disturbance favour Bromus tectorum L. invasion
Autor/es:
SPEZIALE, KARINA L.; DI VIRGILIO, AGUSTINA; LESCANO, MARIA N.; PIRK, GABRIELA; FRANZESE, JORGELINA
Revista:
PeerJ
Editorial:
PeerJ
Referencias:
Lugar: London; Año: 2018 vol. 6
Resumen:
ABSTRACTBackground. Global change produces pervasive negative impacts on biodiversityworldwide. Land use change and biological invasions are two of the major drivers ofglobal change that often coexist; however, the effects of their interaction on naturalhabitats have been little investigated. In particular, we aimed to analyse whether theinvasion of an introduced grass (Bromus tectorum; cheatgrass) along roads verges andthe disturbance level in the natural surrounding habitat interact to influence the degreeof B. tectorum invasion in the latter habitats in north-western Patagonia.Methods. Along six different roads, totalling approximately 370 km, we set two 50 m× 2 m sampling plots every 5 km (73 plots in total). One plot was placed parallel to theroad (on the roadside) and the other one perpendicular to it, towards the interior of thenatural surrounding habitat. In each plot, we estimated the B. tectorum plant density in1 m2subplots placed every 5 m. In the natural habitat, we registered the vegetation type(grassy steppe, shrub-steppe, shrubland, and wet-meadow) and the disturbance level(low, intermediate, and high). Disturbance level was visually categorized according todifferent signs of habitat degradation by anthropogenic use.Results. B. tectorum density showed an exponential decay from roadsides towardsthe interior of natural habitats. The degree of B. tectorum invasion inside naturalhabitats was positively related to B. tectorum density on roadsides only when thedisturbance level was low. Shrub-steppes, grassy steppes and shrublands showed similarmean density of B. tectorum. Wet-meadows had the lowest densities of B. tectorum.Intermediate and highly disturbed environments presented higher B. tectorum densitythan those areas with low disturbance.Discussion. Our study highlights the importance of the interaction between road vergesand disturbance levels on B. tectorum invasion in natural habitats surrounding roads ofnorth-western Patagonia, particularly evidencing its significance in the invasion onset.The importance of invasion in road verges depends on disturbance level, with betterconserved environments being more resistant to invasion at low levels of B. tectorumdensity along road verges, but more susceptible to road verges invasion at higher levelsof disturbance. All the habitats except wet-meadows were invaded at a similar degree byB. tectorum, which reflects its adaptability to multiple habitat conditions. Overall, ourwork showed that synergies among global change drivers impact native environmentsfavouring the invasion of B. tectorum.