Statement of the ProblemII. References Cited
III. Expected Equipment and Special
The last forty-four years have brought accelerating destruction to Florida’s native orchids (Luer, 1997). Habitat destruction, changing local conditions, pollinator loss and loss of mycorrhizal fungus populations are seen as many of the problems (Beckner, 1997, Mitchell, 1977, Schemske et al., 1994). Lack of information about existing wild populations hampers conservation efforts (Beckner, 1997) augmenting the need for current population survivorship information in setting necessary guidelines for species conservation (Schemske et al., 1994).
The role of mycorrhizal fungus in Florida’s native orchids is not well understood at present; however, studies of other orchid populations have shown it to confer drought and disease resistance, reduce pest damage, and increase general plant fitness (Tommerup, 1988) in addition to being a critical factor in orchid seed germination and growth (Alexander, 1987, Tremblay, 1995). Habitat destruction is a well documented factor in orchid decline (Beckner, 1997), but is not a particular factor in this study, since all the lands surveyed enjoy protected status. Pollinator loss may be a major factor, and while this study will not focus on pollinators, every effort will be made to document pollination and type of pollinators present.
Four hundred and sixteen plant species are listed on Florida’s endangered species, threatened species and species of special concern lists, prepared by the Florida Game and Fresh Water Fish Commission (1996). Sixty-nine of those are species in the family Orchidaceae. Both Cyrtopodium punctatum and Epidendrun nocturnum are included on the state list and classified as Endangered. At present, the U.S. Federal Endangered and Threatened Wildlife and Plants List does not include any of Florida’s orchids (Federal Endangered List, 1994), but updated population information may contribute to future Federal listing. Internationally, the Convention for International Trade in Endangered Species (CITES) recognizes the rarity of many orchid species and acknowledges this by limiting international trade in these and all other orchids (C.I.T.E.S, Appendices, 1992).
The Endangered Species Act of 1973 requires the United States Secretary of the Interior to determine if a species is to be federally protected. This determination will be made “solely on the basis of the best scientific and commercial data available to him after conducting a review of the status of the species" (U.S. Congress, 1988). In carrying out this directive, the Secretary of the Interior must give consideration to species which have been identified as “in danger of extinction . . . by any State agency . . . that is responsible for conservation of fish, wildlife or plants” (U.S. Congress, 1988a).
Both E. nocturnum and C. punctatum were surveyed in 1985 by the State Department of Agriculture, the agency that prepares the plant portion of the Game & Fish sponsored list. C. punctatum was given a rating of S1 (extremely rare) and E. nocturnum was given a rating of S2 (rare) (Florida Natural Areas Inventory, 1997). Surveys done in 1996 and 1997 on the Florida Panther National Wildlife Refuge found C. punctatum in 0.4% and E. nocturnum in 4.2% of total areas surveyed (Sulecki, 1997). Because of orchids’ specific environmental requirements, they can be seen as indicators of the health of the forests and swamps they inhabit. These two species were selected, therefore, because they are rare in Florida, which may be indicative of ongoing threats to their survival and to ecosystem changes which make their continued presence uncertain. Additionally, flowering times, pollinators and habitat requirements differ (Luer, 1972), offering an opportunity to evaluate the effects of different natural history strategies of survivorship in two orchidaceae taxa.
The study will include combined field and lab work. The null hypothesis, that stage-based matrix analysis of orchid populations will show them to be viable (or not in decline), will be tested by gathering stage transition data on individuals within identified populations. Mycorrhizal presence will be surveyed by microscopic inspection of root sections taken at ramdom from survey orchid populations.
Orchid populations for Cyrtopodium punctatum and Epidendrum nocturnum will be selected from five land management areas in the Big Cypress Basin: Florida Panther National Wildlife Refuge, Fakahatchee Strand State Preserve, Big Cypress National Preserve, and Corkscrew Swamp Sanctuary. Individual plants identified as being within a study area will be tagged with permanent metal tags and growth stage will be denoted. Plants will be surveyed once every month and re-censused for movement between stages, survival, pollinia extraction, and numbers of flowers and fruits produced following Tremblay (1997). Stage divisions used will be:
1. seedlingsGathered data will be organized into stage-based projection matrices and evaluated in order to assess survivorship, growth and fecundity over three years.
Under unchanging conditions, the statistical result, termed lambda (l = the equilibrium finite rate of increase), is calculated by the matrix test (a measure of population viability) (Menges, 1990). If l < 1, populations are in decline, if l = 1, populations are stable, and if l > 1, populations are increasing (Tremblay, 1997).
Numerical data will be assembled in a projection matrix A, where each entry a(ij) represents the possibility that an individual plant in stage class(i) at time(t) contributes or moves to stage class(j) by time t + 1. To estimate population size at t + 1, a vector n(1) representing the number of individuals in each stage class at time (t) is multiplied by the matrix:
A: n(t + 1) = An(t). This matrix population model provides a quantitative measurement of the rate and direction of population growth, l (Lambda, the intrinsic growth rate), and the specific parameter (Schemske et al., 1994).
Over long time periods conditions typically change, making rates and direction of population growth vary (Menges, 1990). Therefore, additional analyses will be made for sensitivity and population elasticity. Specifically, a simulation using the projection matrix will be conducted to see if altering a specific demographic parameter (greater and lesser fruit production) will result in a changed population growth rate (Schemske et al., 1994). Sensitivity is a measure of how populations are affected by small changes in a demographic parameter. Population elasticity is calculated as the product of the sensitivity for a parameter and the actual value for that parameter divided by the population growth rate (Schemske et al., 1994), and is a measure of how much change a population can tolerate and still maintain its overall growth rate. These measurements are conducted with the same matrix population model, in which the resulting l (Lambda) value is compared to the matrix population model performed with actual population numbers. The greater the difference in l values, the more significant a parameter is determined to be. However, since effects and magnitude of parameters changes are likely to vary in natural populations, the tests for sensitivity and elasticity are simply indicators of general localized trends (Schemske et al., 1994).
Survey sheets will be used to record demographic parameters and phenotypic (observed) variation. Historic natural catastrophes will be noted for possible inclusion in statistical tests as described by Mangel (1994). Any pollination events and pollinators present at times of inspection will be described and documented. Small sections of the root of one orchid representing each stage of growth, in each survey population, will be stained and microscopically examined for the presence of mycorrhiza (Tommerup, 1988). Assistance will be sought for identification of mycorrhizal species.
Expected Results and Significance
The observation of phenotypic characteristics is important in that it may be an indication of variation in local species. Genetic variation can be a critical factor to consider in protective strategies (Beckner, 1997). Observations of presence and type of pollinators may also shed light on causes for population decline or increase, while presence or absence of mycorrhiza will also be a crucial factor in population dynamics. These data will increase understanding of local population dynamics, a necessary factor in species conservation (Schemske et al., 1994, Beckner, 1997). It is further hoped that the methods developed in this study will be applicable to other endangered orchid species and may be applied to future studies.
Time table and project management
Alexander, C.E. 1987. Mycorrhizal infection in adult orchids IN: Sylvia, D.M., Hung, L.L. and Graham, J.H., eds. Mycorrhizae in the Next Decade - Practical Applications and Research Priorities. IFAS, Univ. Florida, Gainesville, 324-327.
Alvarez-Buylla, Elena R., and Montgomery Slatkin. 1994. Finding confidence limits on population growth rates: three real examples revised. Ecology. 75: 255-260.
Beckner, John. 1997. The Biology of Florida’s Orchids. The Palmetto, Quarterly Magazine of the Florida Native Plant Society. 6.
Behar, Moises. 1995. Evolution and Orchids. American Orchid Society Bulletin. 64: 1326.
Calvo, R.N., and C.C. Horvitz. 1990. Pollinator limitation, cost of reproduction and fitness in plants: a transition - matrix demographic approach. American Naturalist. 136: 499-516.
Caswell, Hal. 1989. Matrix Population Models. Sinauer. Sunderland, Mass. USA.
Florida Game and Freshwater Fish Commission. 1996. Florida’s Endangered Species, Threatened Species and Species of Special Concern, Official Lists. Bureau of Nongame Wildlife, Division of Wildlife.
Florida Natural Areas Inventory. 1997. The Nature Conservancy. Element Occurrence Records for Cyrtopodium punctatum and Epidendrum nocturnum. The Nature Conservancy. No page available.
Holbrook, N.M. 1991. Small plants in high places: the conservation and biology of epiphytes. Trends in Evolution and Ecology. 5: 314-315.
Luer, Carlyle A. 1972. The Native Orchids
of Florida. New York Botanical Institute. W.S. Cowell Ltd., Ipswich,
Mangel, M. And C. Tier. 1994. Four facts every conservation biologist should know about persistence. Ecology. 75: 607-614.
McClaran, Mitchell P., Sundt, Peter C. 1992. Population dynamics of the rare orchid, Spiranthes delitescens. The Southwestern Naturalist. 37: 299.
Menges, E.S. Population Viability analysis for an endangered plant. 1990. Conservation Biology. 4: 41-62.
Merhoff, L.A. 1989. Dynamics of declining populations of an endangered orchid, Isotria medeoliodes. Ecology. 70: 783-786.
Mitchell, Paul. 1997. Encyclia tampensis - the Decline of a Popular Florida Native Orchid? The Orchid Conservation Committee Newsletter. 3: 1-4.
Pavlick, B.M., Ferguson, N., Nelson, M. 1993. Assessing limitations on the growth of endangered plant populations. Biological Conservation. 65: 267-278.
Shemske, Douglas W., Brian C. Husband, Mary H. Ruckelshaus, Carol Goodwillie, Ingrid M. Parker, and John G. Bishop. 1994. Evaluating approaches to the conservation of rare and endangered plants. Ecology. 75:584-606.
Sulecki, Alexandra J. 1997. Orchid, Bromeliad and Fern Survey: Progress Report, January through May. Unpublished report submitted to U.S. Fish and Wildlife Service. 1-5.
Tommerup, 1988. The Vesicular-arbuscular mycorrhizas. Advances in Plant Pathology. 6: 81-91.
Tremblay, R.L. 1997. Distribution and dispersion patterns of individuals in nine species of Lepanthes. Biotropica. 29: unnumbered.
United States Government. 1988. Endangered Species Act of 1973, as amended through the 100th Congress. U.S. Department of the Interior.
United States Government. 1994. Endangered and Threatened Wildlife and Plants. 50 CFR 17.11 and 17.12.
United States Government. Department of the Interior. 1992. Convention on International Trade in Endangered Species of Wild Fauna and Flora. Appendices I, II and III, Title 50, Part 23, Subpart C[d]6.
Researchers will need access to a vehicle
for travel between orchid population sites. Expected gasoline costs
for trips for a three year period
Use of all-terrain vehicle and gas for
2 researchers for 3 years
Metal plant tags and wire for attachment
will be needed
Use of microscope and lab time
Use of computer for statistical analysis
Stipend for part-time research worker
Services of a trained mycologist
Total Cost Estimate: $10,150.00