WATER LEVEL REGIMES CLIMATE CHANGE SCENARIOS TRANSITIONAL HABITATS AND REFUGIA

Transcription

1 WATER LEVEL REGIMES CLIMATE CHANGE SCENARIOS TRANSITIONAL HABITATS AND REFUGIA Scudder D. Mackey University of Windsor/Habitat Solutions Funded by the Great Lakes Fishery Commission USFWS Restoration Act

2 Objectives Identify and delineate least-at at-risk and most-at at-risk aquatic habitats Evaluate probability and potential pathways for contiguous and non-contiguous succession (step-stone stone habitats) and short- term refugia Identify existing and future anthropogenic factors or stressors that limit the ability of the ecosystem to adapt to a new water-level regime.

3 Transitional Habitat A community whose species are adapted to the diverse and varying environmental conditions that occur along the boundary that separates aquatic and terrestrial areas. Boundary or transition zone between the two different habitat types ecotone or edge, typically between land and water.

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5 Natural Flow Regimes Magnitude Timing Frequency Duration Rate of Change Fundamental Characteristics of Flow

6 Water-Level Regime Duration 1 Magnitude Rate of Change Frequency Timing (Seasonal, Monthly, Daily, Hourly)

7 Late Holocene Lake Levels - Lakes Michigan/Huron Historical record Measured Inferred 177 ~160-year fluctuation Algoma phase ~30-year fluctuation Nipissing II phase Historical average ( ) v Calendar year before AD 0 BC Year Courtesy Todd A. Thompson - Indiana Geological Survey

8 Lake St. Clair - Water Level Scenarios BASE CASE LAKE STATISTICS Mean Maximum Minimum Annual Range CHANGE FROM BASE CASE Annual Winter Spring Summer Autumn Growing Season WARM & DRY NOT-AS Warm & Dry Source: David Fay & Yin Fan, Environment Canada WARM & WET NOT-AS Warm & Wet

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10 Habitat Succession/Adaptation Contiguous Succession Non-Contiguous Succession (step-stone stone habitats) Short-term term Refugia (protected areas)

11 Gary Towns - MDNR Saginaw Bay, Michigan

12 Habitat Succession/Adaptation Occurs in Three-Dimensions Non-Contiguous Succession?? Contiguous Succession Commonly assume contiguous upslope/downslope succession (plant communities)

13 How does Non-Contiguous Succession Occur? What are dispersal mechanisms? Air, Water, Soil What are critical thresholds for establishment? Physical: Soil, Water, Energy Biological: Groceries, Predation Connectivity: pattern and distribution Stressors: Natural and Anthropogenic Do we have to tools to predict environmental zones and associated habitat distributions?

14 Transitional Habitats and Refugia Refugia habitat conditions in a near natural state. Isolated, protected environment safe haven reduce threats/stressors. Managed for spatial and temporal continuity (protected from change) Refugia are critical to non-contiguous succession Where are the refugia going to be in 2050?

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16 Lake St. Clair Spawning Sites and Water Level Change Where will these sites be in 2050? Gregory et al. 1982

17 Gary Towns - MDNR Saginaw Bay, Michigan

18 Gary Towns - MDNR Saginaw Bay, Michigan

19 Gratiot Ave I- 94 PROP BASIN MARI Cotton Rd There are Boatloads of Marinas and associated infrastructure SUNUP MARINA Callens R BOSUN-WALTS MAR AB AND NB MARIN Jefferson 21 Mile Rd BRIDGE BAIT LAGOS ICE CAPTAINS COVE AMERICAN MARINA COTTON RD ICE William P Rosso Hwy SELFRIDGE PAS SELFRIDGE SF 1,185.5 ft. Grid 512 (13) c c SANG BASE MARIN Henry B Joy Blvd c c c ISLAND COVE MAR LANDS END Trwin St MAC AND RAY MAR MCMACHEN MARINE Harley Ensign SF 3,816.6 ft. MARKLEY MARINE c c c c c c c I- 94 SUNDOG MARINA C&N Ml MAR MARINA SALV MAR C&N MARINA ROYS BOATS HARLEY PAS

20 Channelization and Armoring Protection of Property Wharf out to Navigable Waters

21 Summary There is a link between dynamic abiotic processes, habitat structure, and biological communities Dynamic abiotic processes that create and maintain habitat structure will change in response to altered water- level regimes How do we anticipate these changes and what are the potential impacts?

22 Restoration Opportunities Where possible, restore natural channel or shoreline morphologies and connections, use flow regimes/natural processes to create and maintain habitat structure Restore natural habitat pattern, distribution, and function (the past is the key to the future) Find beneficial uses for dredge material (habitat restoration, creation) Soften shoreline/distributary channel banks Reconnect distributaries with wetlands, delta plain, interdistributary bays Proactive and anticipatory long-term resource management

23 HEC Environmental Zones Environmental Zone Connecting Waters and Channels Deltaic Lake Low Energy Area Shallow water (bank) and backwater areas, riparian wetland habitat Interdistributary bays, delta plain, deltaic wetland habitat Embayments, coastal wetland habitat, open lake High Energy Area Deep water (thalweg) and main channel areas Distributary channels, Delta margin nearshore Coastal margin nearshore, open lake

24 Connecting Waters and Channels Embayment Deltaic Lake Deltaic Margin Nearshore Open Lake Environmental Zones based on dominant physical processes and hydrogeomorphic pathways Coastal Margin Nearshore