Animal-Mediated Dispersal and Clonal Growth Drive Prunus cerasus Invasion in Andean Temperate Forest.

Abstract

Invasive woody species often exhibit long-distance seed dispersal by animals as well as clonal reproduction. However, studies on invasions have rarely focused on both types of reproduction. Our study aimed to identify animal species transporting seeds of Prunus cerasus L. to distant areas in Los Alerces National Park (Argentina) and determine the relevance of animals and clonality at different stages of invasion. We identified the animal species responsible for depulping seeds and estimated the seed dispersal distances generated by foxes and birds. We examined the recruitment and mortality of P. cerasus saplings in an invaded area of Los Alerces National Park over six years (2013-2018). In addition, we assessed the proportion of saplings originating from the germination of depulped seeds versus clonal reproduction in three areas at different invasion stages. Foxes [Lycalopex culpaeus (Molina, 1782)] moved 44% of the seeds more than 1 km, whereas birds moved more than 70% of the seeds less than 30 m. Our results suggest that germination and long-distance seed dispersal by foxes are primarily responsible for the spread of P. cerasus to new areas, whereas clonal reproduction significantly contributes to local expansion. Animals were not relevant when the invasion advanced; mortality and clonality accounted for 95% of the variability in the number of individuals. However, animals were fundamental at the initial stage; 100% of saplings originated from the germination of depulped seeds. Finally, we propose a conceptual model to understand the role of animals in the spread phase of invasion.