9810674 Rundel Desert annuals have been an important group for study by many ecologists, including population biologists modeling strategies of life history adaptations. Such models have generally assumed a bet-hedging strategy in desert annuals in which not all seeds germinate when good growing conditions occur following fall and winter rains. There are limited data suggesting that desert annuals have dormancy mechanisms that allow a conservative strategy in which subsets of seed pools germinate over a series of years. The close phylogenetic relationship between a number of desert annuals and post-fire chaparral annuals, which have a predictive germination strategy cured by chemical signals, suggests that predictive germination strategies may also be present among desert annuals. This project will be investigating the effect of environmental chemical cues for germination in a number of desert annuals from the winter-rainfall Mojave and Colorado Deserts in California. El Ni o conditions in 1997-1998 are providing unusual conditions which have produced abundant germination and seed set of both common and rare desert annuals.
