Aleopatía biológica y sus consecuencias en el reclutamiento de plántulas en un bosque boliviano neotropical

Abstract

Distance-dependent predation reduces the presence of conspecific seedlings near parental trees originating free spaces for seed arrival and heterospecific seedling establishment. However, seedling survival near adult trees can be related with other mechanisms such as allelopathy. Triplaris americana (Polygonaceae) is a tree species characterized by presenting a scarce con- and heterospecific seedlings recruitment under its canopy, which suggests the existence of chemical or biological allelopathic agents. We evaluated the allelopathic effects of both aqueous extracts of mature leaves and defensive activities of resident ants (Pseudomyrmex triplarinus, Pseudomyrmecinae) on seed removal and seedlings survival. We considered distance to T. americana tree, exclusion of seed consumers and seedling predators, and habitat fragmentation as study variables. Aqueous extracts did not inhibit seed germination. Resident ants did not remove the seeds under the canopy of host plant. The main seed consumer was the leaf-cutting ant Atta sexdens (Myrmicinae). In contrast, seedling leaves under the canopy of T. americana were partial or totally pruned by the resident ant species. Results suggest that scarce seedlings recruitment under the canopy of T. americana may be consequence of active defense by the resident ants, acting as a biological allelopathic agent. Ecological consequences of defense by ants are discussed.