Willard, Debra A. , 2006, Ecosystem History: Terrestrial and Fresh-Water Ecosystems of southern Florida.Online Links:
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.001. Longitudes are given to the nearest 0.001. Latitude and longitude values are specified in Degrees and decimal minutes.
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.
The flattening of the ellipsoid used is 1/298.257.
For the South Florida Pollen Data the data for each collection site include the sample id and raw abundance data for each species identified. In the 1960s dataset, raw abundance was back-calculated from percentage data because original raw data was unavailable. The data for the 1990s dataset include the sample number and map ID and percent abundance for each species. See the individual datasets for the species found at the sites.
Project personnel included Anne Bates, Christopher Bernhardt, Patrick Buchanan, Margo Corum, Julie Damon, Charles Holmes, David Korejwo, Bryan Landacre, Harry Lerch, Marci Marot, James Murray, William Orem, Tom Sheehan, Neil Waibel, Lisa Weimer (deceased), and Debra Willard.
703 648 5320 (voice)
703 648 6953 (FAX)
dwillard@usgs.gov
This project is designed to document the terrestrial ecosystem history of south Florida and is collaborating with other projects at the USGS and other agencies on Florida Bay, Biscayne Bay, and the Buttonwood Embankment. The specific goals of the project are 1) document the patterns of floral and faunal change at sites throughout southern Florida over the last 150 years; 2) determine whether changes occurred throughout the entire region or whether they were localized; 3) examine the floral and faunal history of the region over the last few millennia; 4) determine the baseline level of variability in the communities prior to significant human activity in the region; and 5) determine whether the fire frequency, extent, and influence can be quantified, and if so, document the fire history for sites in the region. Data generated from this project will be integrated with data from other projects to provide biotic reconstructions for the area at selected time slices and will be useful in testing ecological models designed to predict floral and faunal response to changes in environmental parameters.
Sediment cores were collected using a piston corer with a 10 cm diameter core barrel. The core barrel was pushed through the sediments until it contacted the underlying limestone at all sites except in Loxahatchee NWR, where peat thicknesses in excess of 2 meters would require alternative coring strategies. After core collection, sediment was extruded from the core barrel and sampled it at 1 cm increments for the upper 20 cm and at 2 cm increments at greater depths. Sediment lithology was described as samples were extruded. Samples were dried in a 50 deg C oven and subsampled sediments at the base of each core and at 20 cm increments above the base for radiocarbon dating. Bulk peats were dated using conventional radiocarbon dating
Age models for the last century of deposition are based on 210Pb (lead-210) and, where applicable, first occurrences of pollen of the exotic plant Casuarina which was introduced to south Florida in the late 19th century (Langeland, 1990). Lead-210 (210Pb) activity was measured by alpha spectroscopy using the method outlined in Flynn (1968) in which 210Pb and its progeny, polonium-210 (210Po), are assumed to be in secular equilibrium. Supported 210Pb activity was determined by continuing measurements until activity became constant with depth. Excess 210Pb activity was calculated by subtracting the supported 210Pb activity from the total 210Pb activity. Accumulation rates were calculated by fitting an exponential decay curve to the measured data using least squares optimization and making the assumptions of a constant initial excess lead-210 concentration (the CIC [constant initial concentration] model).
In pre-20th century sediments, models are derived from linear interpolation between radiocarbon data points obtained on bulk sediment samples, which were calibrated to calendar years using the Pretoria Calibration Procedure (Stuiver et al., 1993; Talma and Vogel, 1993; Vogel et al., 1993). The shorter hydroperiods and shallower water depths on tree-island heads result in seasonal drying and oxidation of sediments. We have noted that radiocarbon dates from tree-island head sediments appear to be artificially old relative to those in the tail and adjacent marsh. Cores collected in the near tail, directly downstream from the head, have radiocarbon dates and vegetational trends that are consistent both internally and with adjacent wetlands. Therefore, we used cores from the near tail as our representative sites to detect vegetation changes on teardrop-shaped tree islands and for comparison with patterns documented in the adjacent marsh.
Approximately 0.5-1.0 gram of dry sediment was used for palynological analysis. Pollen and spores were isolated from these samples using standard palynological techniques (Traverse, 1988; Willard et al, 2001a,b). After drying and weighing samples, Lycopodium marker tablets with known concentrations of Lycopodium spores were added to approximately 0.5 g of sediment for calculation of absolute pollen concentrations (Stockmarr, 1971). The samples were first acetolyzed (9 parts acetic anhydride : 1 part sulfuric acid) in a hot-water bath (100 deg C) for 10 minutes, then neutralized, and treated with 10% KOH in a hot-water bath for 15 minutes. Neutralized samples were sieved with 10 µm and 200 µm sieves, and the 10-200 µm fraction was stained with Bismarck Brown, mixed with warm glycerin jelly, and mounted on microscope slides. Raw data for pollen samples are reposited in the North American Pollen Database (NAPD) at the World Data Center for Paleoclimatology in Boulder, CO (<http://www.ngdc.noaa.gov/paleo/pollen.html>) and at the US Geological Survey South Florida Information Access (SOFIA) site (<http://sofia.usgs.gov>).
Pollen and spore identification (minimally 300 grains per sample) was based on reference collections of the United States Geological Survey (Reston, VA) and Willard et al. (2004). Absolute pollen concentrations were calculated using the marker-grain method described by Benninghoff (1962). Marker tablets of Lycopodium spores were the source of the exotic grains, and the quantity of Lycopodium spores in the marker tablets was determined by the manufacturer with a Coulter Counter following the procedures of Stockmarr (1973). Absolute pollen concentration was calculated using the formula (Maher, 1981): Pconc=RM/V,
Where: Pconc = pollen per gram dry sediment; R=pollen grains counted/marker grains counted; M=marker grains added; V=dry weight of sediment
Our interpretations of past plant communities are based on the quantitative method of modern analogs (Overpeck et al., 1985). We calculated squared chord distance (SCD) between down-core pollen assemblages and a suite of 197 surface samples collected throughout southern Florida in the early 1960s and 1995-2002 (Willard et al., 2001b and this research) to define the similarity between each fossil and modern pollen assemblage. Internal comparison among surface samples from ten vegetation types indicates that samples with SCD values < 0.15 may be considered close analogs (Willard et al., 2001b). If analogs were present for a fossil assemblage, we identified the source vegetation for the fossil assemblage as one of the twelve types represented in the modern database. We divided cores into pollen zones based on a combination of visual inspection, objective zonation using CONISS (Grimm, 1992), and modern analogs.
Person who carried out this activity:
703 648 5320 (voice)
703 648 6953 (FAX)
dwillard@usgs.gov
Willard, Debra A. Weimer, Lisa M., 1997, Palynological Census Data from Surface Samples in South Florida: USGS Open-File Report 97-0867, U.S. Geological Survey, Reston, VA.Online Links:
Willard, Debra A., 1997, Pollen Census Data from Southern Florida: Sites Along an Nutrient Gradient in Water Conservation Area 2A: USGS Open-File Report 97-0497, U.S. Geological Survey, Reston, VA.Online Links:
Willard, Debra A. Bernhardt, Christopher E.; , 2004, Atlas of Pollen and Spores of the Florida Everglades: Palynology 28, American Association of Stratigraphic Palynologists, Arlington, TX.Online Links:
Marshall, Curtis H. Pielke, Roger A., Sr.; Stey, 200401, The Impact of Anthropogenic Land-Cover Change on the Florida Peninsula Sea Breezes and Warm Season Sensible Weather: Monthly Weather Review v. 132, n. 1, American Meterological Society, Boston, MA.Online Links:
Willard, Debra A. Weimer, Lisa M.; Riegel, W., 2001, Pollen assemblages as paleoenvironmental proxies in the Florida Everglades: Review of Palaeobotany and Palynology v. 113, n. 4, Elsevier Science B.V., Amsterdam, The Netherlands.Online Links:
Willard, D. A. Holmes, C. W.; Korvela, M. , 200302, Paleoecological Insights on Fixed Tree Island Development in the Florida Everglades: I. Environmental Controls: Kluwer Academic Publishers, Dordrecht, Netherlands.Online Links:
Sklar, F. H. and van der Valk A. (editors)
Willard, D. A. Orem, W. H., 2003, Tree Islands of the Florida Everglades - A Disappearing Resource: U.SGS Open-File Report 03-26, U.S. Geological Survey, Reston, VA.Online Links:
Bernhardt, C. E. Willard, D. A.; Marot, M.; , 2004, Anthropogenic and natural variation in Ridge and Slough pollen assemblages: USGS Open-File Report 2004-1448, U.S. Geological Survey, Reston, VA.Online Links:
Willard, D. A. Holmes, C. W.; Weimer, L. M, 2001, The Florida Everglades Ecosystem: Climatic and Anthropogenic Impacts over the Last Two Millenia: Bulletins of American Paleontology v. 361, Paleontological Research Institute, Ithica, NY.
Grimm, E. C., 1992, CONISS: a Fortran 77 program for stratigraphically constrained cluster analysis by the mothod of incremental sum of squares: Computers & Geosciences v. 13, issue 1, Elsevier Science, Ltd., Amsterdam, The Netherlands.Online Links:
Traverse, A., 1988, Paleopalynology: Unwin Hyman, Boston, MA.
Stockmarr, J., 1971, Tablets with spores used in absolute pollen analysis: Pollen et Spores v. 13, Museum national d'histoire naturelle, Paris, France.
Overpeck, J. T. Webb, III, T.; Prentice, I., 1985, Quantitative interpretation of fossil pollen spectra: Dissimilarity coefficients and the method of modern analogs: Quaternary Research v 23, issue 1, Elsevier Science, Ltd., Amsterdam, Netherlands.Online Links:
Willard, D. A., 2004, Tree Islands of the Florida Everglades - Long-term stability and response to hydrologic change: USGS Fact Sheet 2004-3095, U.S. Geological Survey, Reston, VA.Online Links:
Bernhardt, C.E Willard, D. A., 2007, Marl prairie vegetation response to 20th century hydrologic change: USGS Open-File Report 2006-1355, U.S. Geological Survey, Reston, VA.Online Links:
Willard, D. A. Cronin, T. M., 2007, Paleoecology and ecosystem restoration: case studies from Chesapeake Bay and the Florida Everglades: Frontiers in Ecology and the Environment vol. 5, issue 9, Ecological Society of America, ithica, NY.Online Links:
Willard, D. A. Bernhardt, C. E.; Holmes, C, 2006, Response of Everglades tree islands to environmental change: Ecological Monographs v. 76, n. 4, Ecological Society of America, Ithica, NY.Online Links:
Langeland, K., 1990, Exotic Woody Plant Control Florida: Circular 868, Florida Coooperative Extension Service, Florida.
Flynn, W. W., 1968, The determination of low levels of polonium-210 in environmental materials: Analytica Chimica Acta v. 43, Elsevier B. V., Amsterdam, The Netherlands.
Stuiver, M. Reimer, P. J., 1993, Extended 14C database and revised CALIB 3.0 14C age calibration program: Radiocarbon v. 35, n. 1.
Talma, A. S. Vogel, J. C., 1993, A simplified approach to calibrating C14 dates: Radiocarbon v. 35, n. 2, University of Arizona, Tucson, AZ.
Benninghoff, W. S., 1962, Calculation of pollen and spore density in sediments by addition of exotic pollen in known quantities: Pollen et Spores v. 4, Museum national d'histoire naturelle, Paris, France.
Maher, L. J., Jr, 1981, Statistics for microfossil concentration measurements employing samples spiked with marker grains: Review of Palaeobotany and Palynology v. 32, issues 2-3, Elsevier Science B. V., Amsterdam, The Netherlands.Online Links:
Stockmarr, J., 1973, Determination of spore concentration with an electronic particle counter: Arbog v. 1972, p. 87-89, Danmarks Geologiske Undersogelse, Copenhagen, Denmark.
Vogel, J. C. Fuls, A.; Visser, E,; Becke, 1993, Pretoria Calibration Curve for Short Lived Samples: Radiocarbon v. 35, n. 1, University of Arizona, Tucson, Arizona.
The locations of the sampling sites were established by GPS.
The cores were selected for analysis based on x-rays taken of the cores. Those cores selected for further analysis were selected on the basis of laminations or other features which indicated a lack of disturbance.
All cores were taken using the same techniques
Are there legal restrictions on access or use of the data?
- Access_Constraints: none
- Use_Constraints:
- None. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data.
727 803-8747 ext 3028 (voice)
727 803-2030 (FAX)
hhenkel@usgs.gov
South Florida pollen data
The data have no implied or explicit guarantees
| Data format: | Each file contains data for a specific time period in format MS Excel (version unknown) |
|---|---|
| Network links: |
<http://sofia.usgs.gov/exchange/willard/willardsflpollen.html> |
727 803-8747 ext 3028 (voice)
727 803-2030 (FAX)
hhenkel@usgs.gov
Florida and Biscayne Bays Pollen Data
The data have no implied or explicit guarantees
| Data format: | Pollen data is available as a separate spreadsheet for individual sample sites in format MS Excel (version unknown) |
|---|---|
| Network links: |
<http://sofia.usgs.gov/exchange/willard/willardpollen.html> |
727 803-8747 ext 3028 (voice)
727 803-2030 (FAX)
sofia-metadata@usgs.gov
U.S. Department of the Interior, U.S. Geological Survey
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