Seed predation of Araucaria angustifolia (Araucariaceae) by small rodents in two areas with contrasting seed densities in the Brazilian Araucaria forest

We investigated the effects of variation in seed density on small-rodent predation of Araucaria angustifolia seeds. Seed removal experiments were conducted simultaneously in two contrasting stands (seed-poor - planted with the slash pine Pinus elliottii and seed-rich - planted with A. angustifolia) outside the seed production period and also during the seed production period. Predator abundance (evaluated through live-trapping) did not vary significantly between stands. Tracking of thread-marked seeds indicated that rodents frequently move seeds away from the source point and that seed-carrying distance (range 3.91-8.30 m) is not significantly related to area or season. Seed removal rates were high in both areas outside the seed production period but during seed-producing months they were significantly lower in the seed-rich area, supporting the predator-satiation hypothesis. The A. angustifolia strategy of synchronous production of large seed crops but with high between-year variation is potentially successful at limiting the impacts of rodent predators.