Seed removal by rodents in a fragment of dry tropical forest (Risaralda-Colombia)

Objectives. Rodents are the biggest seed predators in Neotropical ecosystems, however, fragmentation affects their presence, therefore seed predation. Materials and methods. The percentage and removal rate of seeds by rodents was recognized in areas of interior, borderline and pasture of a dry forest in the area of Cerritos ? La Virginia (Risaralda?Colombia). Between March and July 2003, rodents present in the forest were identified with the aid of 60 Sherman traps located in different areas of the fragment. To obtain the percentage and removal rate of seeds by rodents, two experiments were conducted, (the first in June and the second one in July) with a random block design, using three types of closures: total (access to insects), partial (access to rodents) and control, (access to any organism), taking into account the location within the fragment (interior, borderline, or pasture). During the first experiment (June) 2700 seeds of Samanea saman were used and during the second one (July) 6000 seeds were used. Results. Four individuals of the Heteromys australis species were captured in the interior of the forest. In June 1577 (44.87%) seeds were removed out by rodents within the interior of the forest. In July 1620 (60.5%) seeds were removed out by rodents within the interior of the forest. Conclusions. The results show a higher seed removal by rodents within the interior of the forest where the risk of predation and refuge availability is higher.