New England Plant Conservation Program Floerkea proserpinacoides Willdenow False Mermaid-weed Conservation and Research Plan for New England Prepared by: William H. Moorhead III Consulting Botanist Litchfield, Connecticut and Elizabeth J. Farnsworth Senior Research Ecologist New England Wild Flower Society Framingham, Massachusetts For: New England Wild Flower Society 180 Hemenway Road Framingham, MA 01701 508/877-7630 e-mail: [email protected] • website: www.newfs.org Approved, Regional Advisory Council, December 2003 1 SUMMARY Floerkea proserpinacoides Willdenow, false mermaid-weed, is an herbaceous annual and the only member of the Limnanthaceae in New England. The species has a disjunct but widespread range throughout North America, with eastern and western segregates separated by the Great Plains. In the east, it ranges from Nova Scotia south to Louisiana and west to Minnesota and Missouri. In the west, it ranges from British Columbia to California, east to Utah and Colorado. Although regarded as Globally Secure (G5), national ranks of N? in Canada and the United States indicate some uncertainly about its true conservation status in North America. It is listed as rare (S1 or S2) in 20% of the states and provinces in which it occurs. Floerkea is known from only 11 sites total in New England: three historic sites in Vermont (where it is ranked SH), one historic population in Massachusetts (where it is ranked SX), and four extant and three historic localities in Connecticut (where it is ranked S1, Endangered). The Flora Conservanda: New England ranks it as a Division 2 (Regionally Rare) taxon. Floerkea inhabits open or forested floodplains, riverside seeps, and limestone cliffs in New England, and more generally moist alluvial soils, mesic forests, springy woods, and streamside meadows throughout its range. New England sites occur on calcareous substrates underlain by marble, slate, or trap rock. Floerkea is among the very earliest species to emerge in the growing season. Its seeds germinate in winter and seedlings are visible in late March to early April. Plants primarily self-pollinate; pollinators appear to be very few for this species. Plants live only 60-70 days, maturing an average of 4-12 seeds per individual and senescing by mid-June. The majority of seeds do not persist in the soil for longer than a year. Seeds disperse by gravity mainly over short distances, but water dispersal may allow infrequent, long-distance colonization of new sites. Potential threats to the species in New England include invasive species (Aegopodium podagraria, Alliaria petiolata, Ranunculus ficaria and others), trampling by dirt bikes and all-terrain vehicles, non-point-source pollution, hydrological change, and disturbance from construction of a greenway park. Two of the occurrences are on protected land, and others may be protected from habitat conversion by state wetlands legislation. Its unusual life history, as a non-seedbanking, autogamous annual with high fidelity to sites (some of which are disturbance-prone), may make this species vulnerable to local extinction. The conservation objective for Floerkea in New England is to maintain the four extant populations in Connecticut at a mean annual size of 1,000 to 100,000 stems, occupying at least several 100 m2 each. A secondary objective is to survey for populations in each of the states from which it was known historically, with an ultimate goal of locating and maintaining a total of eight populations of at least 1,000 stems each in three separate watersheds. This number reflects the historic distribution of known sites and acknowledges significant temporal variability in population size. Conservation actions to achieve these objectives include: concerted searches at historical and new sites; biennial, quantitative monitoring; assessments of threats from invasive species; notification of park designers of the species' existence; and ex-situ seedbanking and germination trials. i PREFACE This document is an excerpt of a New England Plant Conservation Program (NEPCoP) Conservation and Research Plan. Full plans with complete and sensitive information are made available to conservation organizations, government agencies, and individuals with responsibility for rare plant conservation. This excerpt contains general information on the species biology, ecology, and distribution of rare plant species in New England. The New England Plant Conservation Program (NEPCoP) of the New England Wild Flower Society is a voluntary association of private organizations and government agencies in each of the six states of New England, interested in working together to protect from extirpation, and promote the recovery of the endangered flora of the region. In 1996, NEPCoP published “Flora Conservanda: New England.” which listed the plants in need of conservation in the region. NEPCoP regional plant Conservation Plans recommend actions that should lead to the conservation of Flora Conservanda species. These recommendations derive from a voluntary collaboration of planning partners, and their implementation is contingent on the commitment of federal, state, local, and private conservation organizations. NEPCoP Conservation Plans do not necessarily represent the official position or approval of all state task forces or NEPCoP member organizations; they do, however, represent a consensus of NEPCoP’s Regional Advisory Council. NEPCoP Conservation Plans are subject to modification as dictated by new findings, changes in species status, and the accomplishment of conservation actions. Completion of the NEPCoP Conservation and Research Plans was made possible by generous funding from an anonymous source, and data were provided by state Natural Heritage Programs. NEPCoP gratefully acknowledges the permission and cooperation of many private and public landowners who granted access to their land for plant monitoring and data collection. This document should be cited as follows: Moorhead, W. H. III and E. J. Farnsworth. 2004. Floerkea proserpinacoides Willd. (False mermaid-weed) Conservation and Research Plan for New England. New England Wild Flower Society, Framingham, Massachusetts, USA. © 2004 New England Wild Flower Society ii I. BACKGROUND INTRODUCTION Floerkea proserpinacoides Willdenow, false mermaid-weed (Limnanthaceae), is an herbaceous, autogamous annual of calcareous floodplains, limestone cliffs, wet meadows, and mature, mesic forests. The genus Floerkea is monotypic, and Floerkea proserpinacoides is the only member of the Limnanthaceae in New England. Floerkea proserpinacoides is widespread in North America, with eastern and western segregates separated by the Great Plains. The species is regarded as Globally Secure (G5), but it is listed as rare (S1 or S2) in 20% of the states and provinces in which it occurs. In New England, Floerkea is known from only 11 sites total in New England: three historic sites in Vermont (where it is ranked "Historic"), one historic population in Massachusetts (where it is ranked "Extirpated"), and four extant and three historic localities in Connecticut (where it is ranked S1, Endangered). The Flora Conservanda: New England recognizes Floerkea as a Division 2 (Regionally Rare) taxon (Brumback and Mehrhoff et al. 1996). Floerkea proserpinacoides has been the focus of several detailed studies, so aspects of its life history are well-known. It is a very early spring ephemeral; its seeds germinate in winter and seedlings emerge in late March-early April. Self-pollination is the primary reproductive mode for this species; flower visitors are almost never seen. Plants complete their life cycle in 60-70 days, maturing an average of three seeds per plant, and senescing by mid-June. Most seeds do not persist in the soil seed bank for longer than a year. Dispersal occurs by gravity mainly over short distances, but water may disperse a few seeds (or seedlings), permitting infrequent, long-distance colonization of new sites. Actual threats to the species in New England are largely unknown, but may include invasive species (which are prevalent at at least three of the extant sites), trampling by dirt bikes and all-terrain vehicles, non-point-source pollution, and possible disturbance from construction of a greenway park. Two of the occurrences are encompassed wholly or in part by nature preserves, and wetlands legislation may protect the others from wholesale habitat conversion. Floerkea has an unusual life history; it is an autogamous annual with very low fecundity and minimal seedbanking capacity that appears to move and reestablish only sporadically among sites. These features make individual populations especially vulnerable to disturbance. This Conservation and Research plan reviews in detail the conservation status of Floerkea proserpinacoides, its biology, its biogeography, and the actions that are necessary to ensure its persistence in New England. These actions, including concerted searches at historical and new sites; biannual, quantitative monitoring; assessments of threats from invasive species; notification of park designers of the species' existence; and ex-situ seedbanking and germination trials, are designed to achieve the following overall conservation objective: to protect and maintain four populations of a mean annual size of 1 1,000 to 100,000 stems, occupying at least several 100 m2 each. A secondary objective is, through concerted survey, to relocate and maintain at least two populations in each of the states from which it was known historically (Vermont, Massachusetts,