Project Work Plan

Study Title: Impacts of Hydrologic and Climatic Change on Greater Everglades Marl Prairies, Marshes, and Sloughs
Study Start Date: 10/1/2006 Study End Date: 9/30/2012
Web Sites: http://sofia.usgs.gov/projects/index.php?project_url=tree_islands
Location (Subregions, Counties, Park or Refuge): Everglades National Park, Big Cypress National Preserve, A.R.M. Loxahatchee National Wildlife Refuge, Water Conservation Areas 2 and 3
Funding Source: GE PES
Other Complementary Funding Source(s): None at this time
Funding History: FY07; FY08, FY09; FY10, FY11.
Principal Investigator(s): Debra A. Willard
Study Personnel: C. Bernhardt, B. Landacre, M. Marot, T. Sheehan, J. Sah, P. Conrads.
Supporting Organizations: South Florida Water Management District; Everglades National Park; A.R.M. Loxahatchee National Wildlife Refuge, Big Cypress National Preserve, US Fish & Wildlife Service.
Associated / Linked Studies: Development and Stability of Everglades Tree Islands, Ridge and Slough, and Marl Prairies (ended 2006); Synthesis of South Florida Ecosystem History Research (ended in FY07); Sea Level Rise and Climate Change - Impacts on the Greater Everglades Ecosystem and Restoration.

Overview & Objective(s): The initial objective of this project is reconstruction of marl prairie vegetation and hydroperiod for the last few centuries to evaluate impacts of climate variability and anthropogenic alteration of hydrology on this critical habitat. This research builds upon previous work throughout the Greater Everglades wetland that documents responses of tree islands and the ridge and slough landscape to natural and anthropogenic hydrologic change (completed 2007). This task requires: 1) multi-proxy analyses (pollen, charcoal, carbon isotopes, geochronology) of sediment cores from marl prairie habitats; and 2) refinements to the existing Everglades pollen calibration dataset by collecting and analyzing surface samples along vegetation transects established by M. Ross and colleagues at Florida International University. An additional objective of the project is refinement of down-core estimates of hydroperiod and stage by calibrating results from new and existing cores with nearby stream gage records. For this task, fine sampling of several new cores will be paired with stream gages with the longest records to calibrate pollen-based estimates of hydroperiod using instrumental records. The resulting refinements will be used to re-evaluate paleohydrologic evidence from ~75 existing sites and develop an Everglades-wide hydrologic reconstruction for pre- and post-drainage time slices. Proxy records preserved in Everglades sediments provide an archive of wetland response to a series of natural and anthropogenic hydrologic experiments during the last few millennia and document the impacts of multidecadal climate processes on wetland communities. By extending the period of record of observations in this "living laboratory of change", these data improve our ability to forecast future ecosystem response to a broad range of climate and management scenarios.

Specific Relevance to Major Unanswered Questions and Information Needs Identified: (Page numbers below refer to DOI Science Plan.)

The importance and application of ecosystem history research to restoration goals has been identified in the DOI Science Plan in Support of Ecosystem Restoration, Preservation, and Protection in South Florida, the USGS Science Plan for south Florida, and the Everglades Multi-Species Avian Ecology and Restoration Review. The DOI Science Plan lists the need to "ensure that hydrologic performance targets accurately reflect the natural predrainage hydrology and ecology" as one of its three primary science goals (DOI Science Plan 2005, p. 16). The USGS Science Plan for south Florida (2007 draft, p. 7) identifies five primary science goals, the second of which is to "determine the historical ecological setting of the Everglades." The Everglades Multi-Species Avian Ecology and Restoration Review recognized the value of paleoecological research in understanding patterns and causes of historical vegetation changes and recommended continued research to synthesize and integrate results from previous and ongoing paleoecological studies to inform restoration planning (SEI, 2007, p. 22). The overall goal of this project, and related previous ecosystem history projects, is to document the predrainage distribution of vegetation and reconstruct paleohydrology of marl prairies, marshes, and sloughs of south Florida, in response to client groups that have been tasked with setting performance measures and targets for these key wetland habitats.

The immediate goals of this project are to develop a spatially complete reconstruction of the vegetation and hydrologic history of Everglades marl prairie habitats, to determine the timing of initial marl accumulation, and to improve our understanding of the patterns and causes of historical vegetation change. These data will be critical to improve forecasts of marl prairie response to different restoration scenarios. In subsequent years, we intend to synthesize data from wetland habitats throughout the Everglades and reconstruct vegetation and hydrology for specific time slices (i.e., predrainage Everglades (~AD 1850), early 20^th century (~AD 1940), and post-C&SF Project (~AD 1960-1970). These data are needed to validate model estimates of predrainage hydrology and to verify impacts of different hydrologic changes on a range of wetland habitats.

A number of specific "major unanswered questions" listed in the DOI Science Plan can be answered by this research. These include the following:

Arthur R. Marshall Loxahatchee NWR Internal Canal Structures

1) "What hydrologic targets will restore the natural predrainage hydrology?" (DOI Science Plan, p. 42)

2) "What is the ecological response to hydrologic change?" (DOI Science Plan, p. 42).

Water Conservation Area 3 Decompartmentalization and Sheetflow Enhancement

3) "What were the physical and ecological conditions in the Greater Everglades prior to drainage and modification, including physical, chemical, and biological processes responsible for development and persistence of soils and geomorphological patterns in the historical Everglades landscape" (DOI Science Plan, p. 71)

Additional Water for Everglades National Park and Biscayne Bay Feasibility Study

4) "What were the physical and ecological conditions in Shark River and Taylor Sloughs and Biscayne Bayprior to drainage and modification, including historic hydrologic, geologic, ecological, and water quality conditions?" (DOI Science Plan, p. 71).

Landscape-Scale Modeling

5) "What are the physical conditions in the Greater Everglades prior to drainage...?" (DOI Plan, p. 92)

Recovery of Vegetative Communities and Multiple Animal Species

6) "How do we optimize the benefits of restoration for protected avian species in South Florida while minimizing tradeoffs caused by conflicting habitat needs?" (DOI Plan, p. 110)

This study supports these CERP projects by 1) conducting research to reconstruct past vegetation and hydrology and understand relative impacts of natural climate variability and human alteration of hydrology on critical habitats; 2) determining the primary external drivers of habitat formation and degradation; 3) providing modelers with data on historic/predrainage conditions to validate model estimates of predrainage hydrology; and 4) providing a predrainage land-cover dataset for use in a range of climate and hydrologic models.

Specific Relevance to USGS Mission:

This project is directly related to two science directions in the USGS Science Strategy (USGS Circ. 1309): 1) Understanding Ecosystems and Predicting Ecosystem Change and 2) Climate Variability and Change. We are investigating the causes and consequences of ecological change over long timescales to understand impacts of natural and anthropogenic changes on the habitats throughout the greater Everglades ecosystem. These techniques are applicable to wetland and other terrestrial habitats throughout the world. This research is aimed at understanding the interactions between biological and nonbiological components of the ecosystem and evaluating consequences of environmental change for different components of the ecosystem. We use results from this research to inform land managers and policy makers on likely response of the greater Everglades wetland to different management and climate scenarios. This investigation contributes to the Climate Variability and Change direction by reconstructing late Holocene climate paleohistory and climate-related ecological, biological, and physical responses. These provide a baseline level of variability for habitats within the ecosystem and provide a basis to forecast impacts of future climate changes on this wetland ecosystem.

Status: In FY09, we completed analysis of pollen and charcoal abundance and developed age models for five marl prairie cores representing five different subpopulations of the Cape Sable Seaside Sparrow (CSSS). Combined with earlier research, we have generated paleoecological data from at least one site in each CSSS subpopulation. Six additional cores have been described, photographed, and sampled for further analysis. Completed analyses indicate that the timing of initial marl accumulation varied greatly throughout the Greater Everglades marl prairie habitat. At some sites, marl accumulation was initiated during the 20^th century, but at other sites, marl began accumulating well before onset of water management, ranging from 300 to nearly 3000 years before present. The timing of vegetation shifts to modern, marl-prairie assemblages also is variable, ranging from ~300 years before present to ~AD 1900. These results indicate considerable spatial variability in the longevity of modern marl prairie habitats.

Recent Products:

1. Bernhardt, C.E. and Willard, D.A., 2006. Marl prairie vegetation response to 20^th century hydrologic change. U.S. Geological Survey Open-file report 2006-1355.
2. Willard, D.A., Bernhardt, C.E., and Saunders, C., 2008. Vegetation and hydrologic history of Everglades marl prairies: paleoecological evidence from Big Cypress National Preserve. 2008 GEER Conference.
3. Willard, D.A., Bernhardt, C.E., and Brandt, L.A., 2008. Response of wetlands in the Arthur R. Marshall Loxahatchee National Wildlife Refuge to hydrologic change: anthropogenic and climate impacts. 2008 GEER conference.
4. Bernhardt, C.E. 2008. Palynological evidence of anthropogenic activity on tree islands. Greater Everglades Ecosystem Restoration Conference, July 28- August 1, 2008, Naples FL.
5. Larsen, L., Aumen, N., Bernhardt, C., Engel, V., Givnish, T., Hagerthey, S., Harvey, J., Leonard, L., McVoy, C., Noe, G., Nungesser, M., Rutchey, K., Sklar, F., Troxler, T., Volin, J., and Willard, D., 2008. The Role of Flow and Transport Processes in Ridge/Slough/Tree Island Pattern Dynamics. 2008 GEER conference.
6. Bernhardt, C.E., and Willard, D.A. 2009. Response of the Everglades ridge and slough landscape to climate variability and 20^th- century water management. Ecological Applications 19: 1723-1738.
7. Willard, D.A. and Bernhardt, C.E., 2009. Natural vs. anthropogenic hydrologic variability in the Florida Everglades: a paleoecological perspective. 2009 National Conference on Ecosystem Restoration.
8. Larsen, L., Aumen, N., Bernhardt, C., Engel, V., Givnish, T., Hagerthey, S., Harvey, J., Leonard, L., McCormick, P., McVoy, C., Noe, G., Nungesser, M., Rutchey, K., Sklar, F., Troxler, T., Volin, J., and Willard, D., in review, Recent and historic drivers of landscape change in the Everglades ridge, slough, and tree island mosaic. Critical Reviews in Environmental Science and Technology.
9. Bernhardt, C.E., Brandt, L.A., and Willard, D.A., in prep. Developing sustainable restoration goals in the Everglades wetland: application of paleoecological evidence in Arthur R. Marshall Loxahatchee National Wildlife Refuge. Environmental Management.
10. Bernhardt, C.E. In review. Native Americans, regional drought, and landscape evolution in the Florida Everglades. The Holocene.
11. Presentation to client agencies at GE PES-organized Climate workshop - February 2008: Everglades Wetland Response to Climate Change (Willard)
12. Presentation to client agencies and colleagues at SFWMD-organized workshop on Ghost Tree Islands, May, 2008: Patterns of Development of Fixed Tree Islands and the Ridge and Slough Landscape (Willard)
13. Presentation at A.R.M. Loxahatchee National Wildlife Refuge Annual Science Workshop, August, 2009: Response of Arthur R. Marshall Loxahatchee National Wildlife Refuge wetlands to hydrologic changes: anthropogenic and climate impacts (Brandt)
14. Presentation to Big Cypress Preserve Research Symposium, October 2009: Paleoecology of Deep Lake, Big Cypress National Preserve, Florida (Bernhardt)
15. Participated in workshop on Past, Present, and Future Climate Change Drivers and Everglades Restoration, organized by Florida Coastal Everglades Long-Term Ecological Research group, October, 2009 (Bernhardt)

Planned Products:

1. Journal article on long-term patterns of vegetation and hydrology in Everglades marl prairie habitats: Willard, Bernhardt, Saunders
2. Journal article on pollen-vegetation calibration from transects in Everglades National Park: Willard, Bernhardt, Sah, Ross
3. Report/journal article on carbon isotopic patterns from Everglades marl prairie habitats: Sah, Ross
4. Synthesis of paleovegetational and paleohydrologic data from >75 sites in greater Everglades ecosystem
5. USGS Fact Sheets on ecosystem history patterns from marl prairie habitats and A.R.M. Loxahatchee National Wildlife Refuge

WORK PLAN

Title of Task 1: Impacts of Hydrologic and Climatic Change on Greater Everglades Marl Prairies, Marshes, and Sloughs
Task Funding: USGS Priority Ecosystems Science
Task Leaders: D.A. Willard
Phone: 703-648-5320
FAX: 703-648-6953
Task Status (proposed or active): Active
Task priority: High
Time Frame for Task 1: FY07; FY08, FY09; FY10, FY11.
Task Personnel: C. Bernhardt, B. Landacre, J. Sah, T. Sheehan, D. Willard

Task Summary and Objectives:

The initial objective of this project is reconstruction of marl prairie vegetation and hydroperiod for the last few centuries to evaluate impacts of climate variability and anthropogenic alteration of hydrology on this critical habitat. This research builds upon previous work throughout the Greater Everglades wetland that documents responses of tree islands and the ridge and slough landscape to natural and anthropogenic hydrologic change (completed 2007). This task requires: 1) multi-proxy analyses (pollen, charcoal, carbon isotopes, geochronology) of sediment cores from marl prairie habitats; and 2) refinements to the existing Everglades pollen calibration dataset by collecting and analyzing surface samples along vegetation transects established by M. Ross and colleagues at Florida International University. An additional objective of the project is refinement of down-core estimates of hydroperiod and stage by calibrating results from new and existing cores with nearby stream gage records. For this task, fine sampling of several new cores will be paired with stream gages with the longest records to calibrate pollen-based estimates of hydroperiod using instrumental records. The resulting refinements will be used to re-evaluate paleohydrologic evidence from ~75 existing sites and develop an Everglades-wide hydrologic reconstruction for pre- and post-drainage time slices. Proxy records preserved in Everglades sediments provide an archive of wetland response to a series of natural and anthropogenic hydrologic experiments during the last few millennia and document the impacts of multidecadal climate processes on wetland communities. By extending the period of record of observations in this "living laboratory of change", these data improve our ability to forecast future ecosystem response to a broad range of climate and management scenarios.

Work to be undertaken during the proposal year and a description of the methods and procedures:

Pollen and charcoal analysis will be completed on six marl prairie cores selected in consultation with colleagues at Everglades National Park. Age models based on radiocarbon dates, short-lived radioisotopes (²¹⁰Pb and ¹³⁷Cs), and pollen biostratigraphy will be generated for each core. Stable carbon isotopes will be analyzed from at least three sediment cores, determined in consultation with colleagues. Other previously collected cores will be described, photographed, and sectioned for future analyses. Pending issuance of a sampling permit from Everglades National Park, field work will be conducted for three purposes. First, a series of surface samples will be collected along vegetation transects established by M. Ross to refine pollen-based interpretation of past vegetation in marl prairie habitats and Shark River Slough. Second, sediment cores will be collected at sites on Cape Sable known to be previously occupied by Cape Sable Seaside Sparrows. These cores will be used to determine vegetation and hydrologic characteristics associated with CSSS occupation and abandonment. Third, sediment cores will be collected at up to six additional sites in Taylor Slough and Shark River Slough. These sites will be co-located with stream gages in consultation with P. Conrads and F. Marshall for model calibration studies.

Work to be undertaken in future years:

FY2011 and 2012 efforts will focus on: 1) completion of marl-prairie research and submission of manuscripts to a peer-reviewed journal; 2) pollen analysis of surface samples obtained in FY10 and drafting a manuscript on results from the pollen-vegetation calibration study; and 3) pollen analysis of sediment cores collected in Taylor and Shark River Sloughs and collaboration with modelers to develop method to statistically infer past hydroperiods from down-core pollen assemblages

Specific Task Product(s):

1. Journal article on long-term patterns of vegetation and hydrology in Everglades marl prairie habitats: Willard, Bernhardt, Saunders
2. Journal article on carbon isotopic patterns from Everglades marl prairie habitats: Sah, Ross
3. Journal article on pollen-vegetation calibration from transects in Everglades National Park: Willard, Bernhardt, Sah, Ross
4. Synthesis of paleovegetational and paleohydrologic data from >75 sites in greater Everglades ecosystem