TY - JOUR T1 - Reproduction and growth of the chaparral geophyte, Zigadenus fremontii (Liliaceae), in relation to fire JF - Plant Ecology Y1 - 2003 A1 - Tyler, C. A1 - Borchert, M. KW - bulb KW - California KW - fire-dependent reproduction KW - fire-induced flowering KW - germination KW - life-history KW - long-lived KW - pityopsis-graminifolia KW - populations KW - postfire KW - seedling establishment KW - soil fertility AB - Zigadenus fremontii is often a striking component of the flora following fire in the chaparral. Like other geophytes, it produces large numbers of flowers in the first spring after a burn. Although these plants are most conspicuous in the early postfire environment, the question that remains is, how do they persist in the interval between fires? To address this we investigated differences in the growth and reproduction of Z. fremontii in burned and unburned chaparral. We monitored marked individuals for nine years at three sites: two that were burned in 1990 and one in the same area that was in unburned mature chaparral. We measured leaf area, and production of flowers and fruits. We also conducted seed experiments in the field to determine the rates and timing of germination. We found that reproduction occurs only in the immediate postfire period: flowering and production of fruits and seeds in the first year following fire, and seedling establishment by year 3. There was a cost of reproduction; plants that flowered (in the burn area) had negative growth rates the following year. In contrast, plants in unburned chaparral, which did not flower, had positive growth rates over the same period. Moreover, plants that produced the most flowers had the lowest growth rates. In the unburned chaparral site, plants were not dormant as predicted from previous literature; instead they produced leaves nearly every year. In most years the average leaf area per plant was greater than that in the burned sites. Our results indicate that postfire reproduction depends on growth and carbohydrate storage in the inter-fire period. We also suggest that this species is relatively long-lived for a herbaceous perennial. VL - 165 UR - ://000179659700002 JO - Plant Ecol Plant Ecol ER - TY - JOUR T1 - Are long fire-free periods needed to maintain the endangered, fire-recruiting shrub Arctostaphylos morroensis (Ericaceae)? JF - Conservation Ecology Y1 - 2002 A1 - Odion, D. A1 - Tyler, C. KW - Arctostaphylos morroensis KW - California coast KW - endangered species KW - fire-dependent germination KW - fire-related extinction risk KW - maritime chaparral KW - Morro manzanita KW - obligate-seeder KW - postfire seedling recruitment KW - seed bank KW - shrublands KW - viable seed AB - Morro manazanita (Arctostaphylos morroensis) is a distinctive shrub restricted to a small area along the coast of California, USA. This endangered species faces two opposing fire-related extinction risks: (1) adults are killed by fire, and (2) recruitment opportunities only occur with fire. These strongly limit the capacity of this, as well as other obligate-seeding species, to recover from a population decline, which may result if there is an inadequate amount of time between fires for replenishment of sufficient seed populations. Using a prescribed burn, we tested whether the size of the seed bank that had accumulated in a 40-yr-old stand would prove adequate for maintaining A. morroensis population sizes through fire. Prior to the burn, we found ~11,000 seeds/m2 in the soil, mostly in the top 5 cm. However, the number of viable seeds was substantially lower (334 seeds/m2), and less than one-third of these survived the experimental fire (99 seeds/m2). Germination occurred only in the first two wet seasons after the fire, and may have been adequate to replace the number of A. morroensis present before the burn. However, most seedlings did not survive their initial summer drought. After three years, the new population of A. morroensis was less than half the size of the parent population. Further mortality is expected because the remaining seedlings are highly clumped. We conclude that A. morroensis may require considerably longer than 40 years to establish an adequate seed bank to compensate for mortality and prevent population decrease or local extinction. This prolonged risk is perhaps explained by specialization of this species to a historic regime of relatively infrequent fire. There are many obligate-seeding species in fire-prone shrublands that may not be resilient to a regime of fire more frequent than that with which they evolved. VL - 6 UR - http://www.consecol.org/Journal/vol6/iss2/art4 ER - TY - CHAP T1 - Demography and regeneration of oaks in the foothill woodlands of central California: A review of the scientific literature T2 - Coast Ranges Oak Woodland Network: Final Report and Proposal for Funding to the David and Lucille Packard Foundation Y1 - 2002 A1 - Tyler, C. A1 - Kuhn, W. A1 - Davis, F. JF - Coast Ranges Oak Woodland Network: Final Report and Proposal for Funding to the David and Lucille Packard Foundation PB - University of California ER - TY - CHAP T1 - Demography and regeneration of oaks in the foothill woodlands of central California: A review of the scientific literature T2 - Coast Ranges Oak Woodland Network: Final Report and Proposal for Funding to the David and Lucille Packard Foundation Y1 - 2002 A1 - Tyler, C. A1 - Kuhn, W. A1 - Davis, F. JF - Coast Ranges Oak Woodland Network: Final Report and Proposal for Funding to the David and Lucille Packard Foundation PB - University of California ER -