Are small abandoned plantations a threat for protected areas in Andean forests? The potential invasion of non-native cultivated species

Abstract

Abandoned farms with small fruit plantations of the non-native species Prunus cerasus and Malus domestica are common in protected areas of the temperate forests of southern South America (TFSA), in Patagonia. Our aims were to determine whether an invasion of P. cerasus and M. domestica might be starting in protected areas, and whether either native or alien animal species are involved in the dispersal process. We evaluated sapling and seed spread, adult tree distribution in three habitats, and seed dispersal vectors of P. cerasus and M. domestica in “Los Alerces” National Park (Argentina). We sampled mature trees, saplings and seeds of P. cerasus and M. domesticain in two plots located next to plantations. Adult trees and mammal faeces also were searched for on roads, hiking trails, deforested areas, plots and transects opened by us. We monitored fruiting trees with cameras and we caught birds to obtain faeces. Saplings of P. cerasus were abundant and their locations were not related to adult locations, but saplings of M. domestica were rare. Ninety-two percent of P. cerasus adult trees were found in successional forest, whereas 99% of M. domestica trees were in deforested areas. Faeces of native foxes contained high number of intact seeds of both plant species studied, but we did not find any in the bird faeces. Our results indicates that P. cerasus has been invading natural habitats in protected areas of TFSA, and that foxes can be the major dispersal vectors. Further, successional forest is the most invasible habitat.