Gradients on mountain trails in the mendoza andes, argentina

Background and aims: Climate change, livestock and increasing tourism use favor the dispersal of non-native plants, threatening the conservation of high Andean ecosystems. We studied the distribution patterns of native and non-native species in recreational trails of mountains. M&M: We implemented the MIREN T-Trails protocol in six trails (2400-3600 m a.s.l.) in two protected areas of the central Andes of Mendoza, located in the Cordilleras Results: We found 180 native and 41 non-native especies. Native species richness peaked at intermediate elevations, while non-native richness decreased with elevation. The Cordillera Frontal had more native richness than the Cordillera Principal (114 versus 71 native, respectively), but regional richness of exotics was lower in the Cordillera Frontal (20 versus 28 exotic, respectively). The non-native richness per plot was higher in the Cordillera Frontal than in the Cordillera Principal. In turn, the altitudinal distribution range of non-native was greater in the Cordillera Frontal, showing that exotics are more widely distributed in more humid sites of the arid Andes. Two abundant non-natives, Taraxacum officinale and Cerastium arvense, were present along the entire surveyed gradient in the Cordillera Frontal, reaching 3600 m a.s.l. We found seven non-natives not previously cited for the region. Conclusions: The new records found extend the known distribution ranges of some non-native species. Our results show that although the number of non-native species was similar near and far from trails, five species were present only at trail edges, suggesting that trails favor invasion processes.