Recommendations for Everglades Restoration

under a Future Climate Scenario

USGS, CES, Florida Sea Grant Sponsored Meeting
April 28 & 29, 2014
Florida Atlantic University Boca Campus

SESSIONS (Download the resources for each session)


Landscape | Vegetation | Wildlife | Northern Everglades
Biogeochemical | Water Management
 | Coastal

Session A: Management framework for landscape systems
Session Leaders: Martha Nungesser & Leonard Pearlstine
Landscape scale analysis of the Everglades requires synthesis of the major physical and biological processes that govern these wetlands. As changes in climate and sea level alter these processes, we anticipate peat loss in the ridge and slough landscapes, alterations in tree island and marl prairie community structure,  saltwater incursion inland in coastal areas, loss of species synchronization, and adaptive changes in plant and animal communities, including novel communities incorporating non-indigenous and opportunistic species. Scientists can anticipate and monitor these shifts as they occur through focused data collection, integrated models, remote imagery, and intimate knowledge of the Everglades wetlands. Scientific collaboration with decision-makers may help promote ecosystem resilience, transition strategies, and changes in ecosystems services and water supply provided by the Everglades.
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Session B: Shifts and challenges to vegetative communities
Session Leaders: John Volin & Arnold van der Valk
The potential impacts of climate change in the Everglades can be examined at multiple scales.  As for all wetlands, hydrology is the major driver that determines the distribution and structure of various the vegetation types in the Everglades.  The number of dominant vegetation types (wet prairies, sawgrass flats, ridges and sloughs, shrubs, and tree islands) historically and currently found in the Everglades is primarily a function of the magnitude of interannual water-level fluctuations.  A change of 25 to 30 cm in interannual water-level fluctuations is expected to change the number of vegetation types in a wetland, based on studies of other wetland types.  Because changes of this magnitude are predicted this suggests that climate change could have a significant impact on the number of vegetation types or zones found in the Everglades.

How will tree islands, ridge and slough areas, wet prairies, etc. fare if the magnitude of interannual water level fluctuations are significantly altered? Which are most vulnerable to a change in hydrology? What implications does change in the relative abundance of various vegetation types have for birds and animals in the Everglades? Within the Everglades, what kinds of changes are expected to occur in various areas (ENP, WCAs) because of a change in the magnitude of interannual due to climate based on contemporary and historical data. Are some areas more vulnerable than others?

Discussion Approach:

  • Can we predict the magnitude of future interannual water-level fluctuations in different part of the Everglades (ENP, WCAs)?   How much confidence do we have in the limited historic data that are available?
  • What do we know about shifts in plant communities due to past natural and anthropogenic changes in hydrology?  Is this information sufficient to realistically predict future shifts in the location and abundance of plant communities due to climate change?
  • Is it possible to manage the hydrology of some parts of the Everglades in order to preserve the historic magnitude of interannual water level fluctuations? If so, what parts?

Some of the uncertainties:

  • How reliable is our information about the magnitude of historic (i.e., predrainage) annual and interannual water level fluctuations in the Everglades?
  • How much do we know about the relative abundance and distribution of various vegetation types prior to drainage?   How reliable is this information?
  • How long does it take for a vegetation types to be lost or replaced by another vegetation type?  Are some vegetation types more vulnerable to changes hydrology than others?  Is there a vegetation type that should be monitored as an indicator of climate change?
  • How will changes in magnitude of interannual water level fluctuations affect fire frequency and intensity?
  • How will future management of water in the Everglades affect the hydrology of the Everglades? 
  • Because of the introduction of invasive species will new vegetation types develop that might replace some of the existing vegetation types?
  • Even if the magnitude of the interannual water level fluctuations is unaffected, will there be a shift in the number of years of high, normal and high water during an interannual cycle? How could this affect the distribution and relative abundance of various vegetation types?
  • What impacts will increased carbon dioxide have on primary production? Peat accumulation?
  • What impacts will changes in temperature have on the composition of plant communities as well as on litter production and decomposition rates? 
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Session C: Managing Wildlife for Sustainability in Changing Climate
Session Leader: Joel Trexler
Our work will focus on sustainability of ecosystem function, primarily related to food-web ecology, as well as threatened and endangered species and impacts of invasive species under a range of possible Everglades futures on a 30-50 year timeframe. Our primary recommendation to date has been that current restoration plans are rendered more critical for wildlife under the most likely scenarios of climate change and our work will continue to clarify and justify this recommendation. To do this, we will explore the impacts of future management with water of varying degrees of compliance with water quality standards; issues of nutrient supply and xenobiotics will be considered. We welcome additional climate scenarios, if any are available, in order to broaden the scope of inference of our recommendations. Finally, we will continue to work on documentation of model uncertainties. The greatest uncertainty is from climate scenarios and we propose to work closely with the Everglades Landscape group to explore how these uncertainties are magnified as they are incorporated into ecological models of wildlife response.

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Session D: Managing Water Quality and Quantity in the Northern Everglades
Session Leader: Karl Havens
The Everglades proper requires an enhanced input of low-nutrient water. The current situation is that a large quantity of water enters the regional ecosystem in the watershed north of Lake Okeechobee, becomes polluted with P and N, and runs off quickly into Lake Okeechobee where much of it is discharged to the ocean via the E and W coast estuaries after major storm events. The challenge is to identify solutions that capture water after peak rainfall, hold as much of the water as possible for use during times of drought, and clean nutrients from the water before it is delivered to the Everglades.  

Some of the possible options:

  • Dispersed storage (minimally restrictive, least regrets)
  • Regional stormwater treatment areas (expensive)
  • Revised regulation schedule for LO (can be done as soon as levee is repaired, risks LO littoral zone)
  • Strengthened levee (would require very expensive project, presumption that LO littoral zone is gone)
  • Regional reservoirs and STAs (expensive)
  • ASR storage (most expensive and uncertain)

 Some of the uncertainties:

  • Need better information regarding temporal distribution of rainfall and drought
  • Need cost comparison of alternatives
  • Need to know benefits per unit cost in terms of both peak flow attenuation and water storage for droughts
  • Need to understand impacts within Lake Okeechobee
    • Largest area of uncertainty involves the submerged vegetation zone of the lake, which likely will experience great variations in depth, sediment type and water quality
    • Also uncertainty regarding potential for littoral zone to recover after very prolonged droughts and presumably expansion of woody vegetation, exotics … and large-scale fires
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Session E: Managing the Everglades by Influencing Biogeochemical Processes
Session Leaders: Dave Rudnick, Sue Newman & Len Berry
The response of the Greater Everglades to climate change and sea-level rise is strongly influenced by biogeochemical processes, which are generally most associated with microbial and plant production and respiration, organic matter decomposition (with many oxidation-reduction reactions), and nutrient cycling in water and soils.  Great attention has been given to the effects of nutrient enrichment (particularly by phosphorus) on the Everglades and hydrologic changes associated with climate change will alter future nutrient inputs to and cycling and transport of nutrients within the Everglades.  Another major issue is how soil elevation dynamics in both freshwater and saline wetlands respond to changing hydrologic patterns, nutrient availability, and salt-water intrusion – all factors influenced both by climate change (with sea-level rise) and Everglades restoration.  Increases or decreases in marsh soil elevation may be the prime determinant of the spatial extent of salt-water intrusion and sea-level rise effects in the Everglades.  Of particular concern is that salt-water intrusion may cause peat collapse in the brackish-freshwater ecotone of the Everglades.  This session seeks to provide specific recommendations to increase the effectiveness management actions to build the resilience of the Everglades and mitigate the effects of climate change and sea-level rise.
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Session F: Water Management Response to Hydrology and Sea Level Rise
Session Leaders: Jayantha Obeysekera & Glenn Landers
In this workgroup, water management response to two primary areas of anticipated future changes will be addressed: (a) Hydrology; and (b) Sea Level Rise. Both are important considerations in developing adaptation strategies for the built-environment and the natural-environment in South Florida.

Changes to hydrology may be due to a variety of factors including modifications to rainfall patterns (both averages and extremes) as well as increases in evapotranspiration altering the water budget in the Everglades system.  Restoration planning to date has used the historical period from 1965 onwards as the basis for the development of options for restoring hydropatterns in the Everglades and balancing those with the needs of the built environment.  In view of climate change, the validity of the approach to use historical period needs to be investigate considering future potential changes in rainfall, evapotranspiration, tributary inflows and sea levels.  Previous investigations have used a scenario-based approach for climate change and they need to be improved using the latest projections for the regional climate in South Florida

With reference to Sea Level Rise, records from the Key West, Miami Beach and other tide station locations around South Florida with roughly 40 years or more of continuous record indicate local historic rates of relative sea level rise (SLR) vary from 2.20 to 2.90 mm/year (8.7 to 11.4 inches/100 years). Due to ongoing global climate change, the rate of relative sea level rise in South Florida is anticipated to accelerate significantly by 2100 and continue at higher SLR rates well beyond 2100.  The future timing and magnitude of changes in the rate of sea level rise is uncertain, so the National Research Council (NRC) has recommended consideration of multiple scenarios representing a range of potential future conditions.  For this technical meeting, four SLR scenarios will be considered by all discussion groups for the period through 2120 (i.e. the next 100 years) based on current USACE and NOAA guidance. This discussion group will identify potential SLR impacts on both developed and natural areas (primarily SE Florida), and then provide risk management recommendations for existing developed areas and long term risk reduction recommendations to help encourage future public and private investments in low risk areas.

Discussion approach:

A high-level review of the previous projections of regional climate information and the sea level rise, and the latest information that will become available in the near future is needed.  A summary of any updates to past previous climate change and sea level rise scenarios will be discussed.  If possible, a set of new scenarios and the hydrologic response using available models will be made before the workshop. Using the above information, potential options for enhancing the robustness and resilience of the current restoration plans will be discussed and documented.  Emphasis will be given to “No regret strategies” (flexible, common sense recommendations that will be responsive to future changes and compatible with current plans) and pilot projects to reduce uncertainties.

Uncertainties:

    • Accuracy and availability of the regional climate projections at scales of interest to Everglades Restoration (e.g. 2milex2mile; daily).
    • Projections of mean sea level and extremes
    • Changes in extremes including rainfall and tropical storms/hurricanes
    • Feasibility of implementing changes to restoration plans.
    • Providing “actionable science” to decision makers
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Session G: Southern Everglades Coastal Systems
Session Leader: Marguerite Koch
Coastal systems of the Greater Everglades, which includes extensive estuaries and saline wetlands, are influenced by watershed and coastal management, as well as by sea-level rise and climate change. Previous workshops identified known sensitivities and hypothesized responses of estuarine benthic communities and coastal wetlands’ soils and plant communities to the combination of fresh-water flow restoration and sea-level rise and climate change. Sea level rise may be the strongest driver of future changes in these communities. The Florida Keys coral reef system is sensitive to local fisheries management, watershed management, and climate change, but the strongest driver currently impacting the reef is increasing temperature. Thermal stress not only directly impacts corals, but also influences disease vulnerability and interacts with water quality conditions to indirectly influence coral mortality. For most of the coastal system, management of fresh-water inputs (quantity, timing, distribution, and nutrient content) and fisheries are primary tools that can be used to moderate and mitigate sea-level rise effects. This session seeks to provide specific recommendations to increase the effectiveness of this mitigation and the resilience of this entire coastal ecosystem in the face of sea-level rise and climate change.
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 Last Modified 11/8/16