Document: TAD-3-45-5

Seed, cache and seedling shadows of an Australian tropical rainforest tree dispersed by white-tailed rats.

THEIMER, T.C.*

Northern Arizona University, Flagstaff, AZ 86011 ¹

Abstract:
The role of white-tailed rats (Uromys caudimaculata) as dispersers of seeds of the Australian tropical rain forest tree Beilschmedia bancroftii was investigated by following the fates of seeds and seedlings over two years. During a mast year, white-tailed rats cached seeds an average of 13m from parent trees in a variety of microsites, but neither distance of cache from parent nor microsite affected the length of time seeds remained in caches. Although none of the 61 cached seeds followed in this study survived to germination, comparison of seed, cache and seedling shadows suggested that most seedlings arose from rat-cached seeds. White-tailed rats cached seeds in both mast and non-mast years, but the time seeds remained on the forest floor and in caches was significantly shorter in non-mast years, suggesting that synchronous seed production increases the probability that some caches survive to germination. Because white-tailed rats are the most common and widespread native mammal capable of dispersing large seeds, this study suggests that they could play an important role in the seed and seedling dynamics of Australian tropical rain forests.

Keywords: masting, predator satiation, rodent, seed dispersal

This abstract is being presented at: 2:00 PM in session:
Oral Session #68: Dispersal of Seeds and Fruits.