Temporal Variation in Boxelder Seed Predation by Small Mammals

Abstract

Acer negundo (Boxelder) is a common tree in eastern North America. Fruits are paired samaras that mature in late summer but persist on trees for months. We examined temporal variation in predation rates by small mammals by attaching samaras to sewing bobbins in a forest in northeastern Wisconsin. We placed samaras in groups of 5 along transects and checked them regularly across 2 fall and 2 spring seasons to determine seed fates. Of the 6702 seeds, 15.26% were consumed, 81.41% were left intact, and 3.33% were aborted. Predation rates were higher in fall than in spring. Granivorous mammals did not secondarily disperse seeds but instead acted solely as seed predators. Releasing seeds over a longer period of time than other species of maples allows trees to increase seed survival by experiencing varying soil conditions and predation rates. Retained sterile fruits may act as decoys that decrease predation rates.