Abstract
Volume 02 (3) 1995
Dynamics of yellow pine chipmunk (Tamias amoenus) seed caches: Underground traffic in bitterbrush seeds
Stephen B. VANDER WALL, Department of Biology, University of Nevada, Reno, Nevada 89557, U.S.A.
Abstract:
Fates of antelope bitterbrush (Purshia tridentata) seeds were monitored from the time the seeds were cached by yellow pine chipmunks (Tamias amoenus) until they germinated nine months later. One thousand seeds were numbered and then radioactively labelled with scandium-46 so that the histories of individual seeds could be followed. The labelled seeds were placed under a bitterbrush shrub in the morning and by that evening chipmunks had gathered most of the seeds and made 110 primary caches within 16 m of the source shrub. During the fall, chipmunks and other rodents visited many of these caches and removed some of the seeds. Thirty-one caches completely disappeared, 28 other caches had some but not all of the seeds removed, and 51 caches remained intact until the time of seed germination. Chipmunks recached about 30% of the seeds they took from primary caches during the late summer and fall at 12 secondary and two tertiary cache sites. The histories of seeds were often complicated. Seeds survived to the time of germination at 86 of the 124 cache sites (79 primary caches, six secondary caches, and one tertiary cache). The population of caches from a particular source plant is dynamic. Seed-hoarding animals frequently move seeds from one storage site to another, and this secondary dispersal has important consequences for the seeds being moved.
Keywords :
secondary dispersal, seed caching, Purshia tridentata, radioactive labelling, scandium-46.
Pages: 261-266