Native bamboo increases biotic resistance to Pinus contorta invasion in temperate forest ecosystems

Abstract

Abstract One of the tree species with the greatest invasive potential worldwide is Pinus contorta Douglas ex Loundon, which is characterized by producing a great number of individuals in short periods of time, generating different impacts on the ecosystems it invades. The genus Chusquea is present in a diverse number of ecosystems in South America. In the temperate forests of Chile and Argentina, it forms dense thickets in the undergrowth as well as in open areas. Its rapid growth and vegetative reproduction, with large numbers of individuals, allow the species to dominate and restrict the establishment of other plant species. This study focused on analyzing the effect of the presence of individuals of Chusquea culeou E. Desv. on the establishment of the invasive species Pinus contorta, as well as on other native herbaceous and shrub species in Araucaria-Nothofagus forest. With this aim, we established 204 plots within the Malalcahuello National Reserve (in the Andes of south-central Chile) along a gradient of P. contorta invasion, where the presence or absence of these species was recorded through different percentages of Chusquea cover. The results showed that the probability of presence of P. contorta decreases significantly in areas where Chusquea cover is greater than 25%. Native species also decrease their presence, but to a lesser extent compared to P. contorta. Our results demonstrate the inhibitory effect of Chusquea for the establishment of other plant species, but more markedly for invasive conifers.