Alien plant species along altitudinal gradients in northwestern Patagonia.

WERENKRAUT, V; SPEZIALE, K. L.; EZCURRA, C.

Bariloche

Congreso; VI Southern Connection Congress, Bariloche, febrero 2010.; 2010

Universidad Nacional del Comahue e Inibioma Conicet

Alien plant invasion had not historically affected high elevations but is currentlyreaching mountain tops. We analyzed the pattern of alien plants species richness alongan altitudinal gradient, its association to environmental variables and described basiccharacteristics of alien species and composition along the gradient. Within NahuelHuapi national park in northwestern Patagonia we climbed 5 mountains setting 100m2plots every 100 m of elevation from bottom to top (range 800-2000 msnm). In each plotwe recorded every vascular plant species, habitat type, collected soil samples andmounted a hobo. Most of the alien species were original from Eurasia and are regularinvaders elsewhere. Many species were recorded at lower elevations than what is foundfor other areas of Argentina and some others at higher elevations than previously found.Clearly alien species richness decreased from bottom to top of the mountains. GLManalyses showed a positive association to native species richness and shrubland habitats,but a negative one to shrub cover and altitude. Lowland diverse habitats support morealien species than mountain tops of north-western Patagonia, which are not yet severelythreatened by alien plants invasions yet. This is probably attributably to the lack ofpropagules given that several species were already recorded at higher altitudes. Giventhe current increase in mountain outdoor activities precautionary management isrequired to prevent future invasions.