BIOLOGICALLY BASED INTEGRATED MANAGEMENT OF INVASIVE AQUATIC AND RIPARIAN WEEDS
Location: Exotic and Invasive Weeds Research
Title: RARE PLANTS IN THE GOLDEN GATE ESTUARY: SCALE AND UNDERSTANDING
| Fiedler, Peggy - EXTRIX INCORPORATED |
| Keever, Meagan - SF STATE UNIVERSITY |
| Partridge, Douglas - BLASLAND, BOUCK & LEE INC |
Submitted to: Australian Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 20, 2006
Publication Date: May 18, 2007
Citation: Fiedler, P.L., Keever, M.E., Grewell, B.J., Partridge, D.J. 2007. Rare plants in the golden gate estuary: scale and understanding. Australian Journal of Botany.55:206-220.
Interpretive Summary: This invited paper will be submitted for peer review and publication in a special issue of the Australian Journal of Botany which will focus on international examples of science support for rare plant population restoration and conservation. The audience will include professional botanists, restoration practitioners, and plant ecologists in academia, government agencies, consulting, and conservation organizations. The paper provides a retrospective of 25 years of rare plant research in the San Francisco Bay region of California. Projects ranging from mitigation monitoring to experimental studies of rare plant demographic responses to restoration management are included to evaluate the relationship between scale of scientific effort and level of understanding. Studies that are limited to annual census of endangered plant distributions are not cost effective and do not yield critical recovery information. Significant cost savings can be achieved with multi-year/multi-species studies. Broad conclusions are that rare plant species persist despite increasing urbanization pressure, and studies have documented larger geographic ranges and population sizes of rare plants than were previously known. Population restoration is possible, but ecosystem functions must be restored prior to reintroduction. Conservation actions to counter exotic species invasions and changes in critical ecological processes are critical for needs restoration success, and should be undertaken in an experimental framework with feedbacks to adaptive management.
We analyzed ten rare plant projects conducted from 1982 to 2005 for trends in scientific findings, project costs, effort, and efficacy. Our purpose was to determine whether generalizations about these factors can be found, and if so, whether they might be useful for designing and implementing successful future rare plant endeavors. Analysis results revealed that rare plant species persist despite their restriction to a highly fragmented and degraded urbanized estuary of more than seven million people. Also important were the findings that with sufficient funding, successful rare plant reintroduction is possible in the short term at minimum. Habitat considerations, however, are paramount - i.e. habitat requirements of a rare species should be known prior to reintroduction if the restoration effort is likely to be successful. Understanding ecosystem functions that support rare species, therefore, remains the highest priority for rare plant restorationists. Project costs varied significantly, as expected, but a "middle ground" provides necessary and sufficient funding to conduct most rare plant work for one or a few species. Costs rise, but not linearly, when additional rare taxa are included. If our experience is applicable elsewhere, taking an ecosystem approach to rare flora protection is most successful and cost effective.