The ecological life history of Arabis laevigata, a facultative biennial native to e. North America, was studied in a rocky deciduous woodland in nc. Kentucky from 1985-1994. Its woodland rock outcrop habitat is stable and thus differs from the ruderal habitat of many other facultative biennials. Seeds of A. laevigata mature in June and dispersal lasts >1 yr; most fall within 0.5m of parents. Seeds have nondeep physiological dormancy, which is broken during winter. Germination occurs in March and April, and seeds that fail to germinate become part of a persistent seed bank. Plants form a rosette the first year and flower in their second or a later year. There was no consistent pattern of transition between size intervals. Vernalization is required for bolting/flowering, but plants are day-neutral. Bolting occurs in March, and anthesis peaks in mid-April. Arabis laevigata is capable of both self- and cross-fertilization and is not agamospermous. Probability of survival and of bolting increased with rosette size, which was highly correlated with number of seeds produced. Low leaf litter cover, low herbivory, and a rock/moss substrate were associated with increased bolting. Flower stalk herbivory was the primary reason many plants that bolted did not produce seeds. Less than 5% of 3,083 plants marked in the seedling stage survived 1 yr, and <1% of them reproduced. Cohorts exhibited a Deevey Type III survivorship curve. Pre-establishment mortality corresponded positively with no (vs partial) leaf litter cover and negatively with increased precipitation. Greater mortality in established plants generally was associated with small (vs. large) size, moderate (vs. low) leaf litter cover, a soil (vs. rock/moss) substrate, herbivory, and low precipitation. We conclude that A. laevigata exhibits a stress-tolerant ruderal (SR) strategy (sensu J.P. Grime's triangular model).

Key words: ecological life history, facultative biennial, reproductive biology, survivorship