Coastal Margins. Scudder D. Mackey, Ph.D. University of Windsor

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1 Coastal Margins Scudder D. Mackey, Ph.D. University of Windsor

2 Nearshore Coastal Margins Nearshore habitats are critical and essential to the Great Lakes ecosystem. Anthropogenic impacts alter substrate characteristics, water depth, water quality, and energy dynamics of the nearshore zone. Anthropogenic impacts have both a direct and an indirect impact on the Lake Erie ecosystem.

3 Nearshore Coastal Margins Problem: Nearshore biological processes and biological linkages to nearshore structural habitats are not well-studied and poorly understood. Significance: Regulatory decisions affecting the nearshore zone are made without adequate scientific data. What elements of the Lake Erie ecosystem are nearshore and coastal habitat limited?

4 Structural Habitat Created by the dynamic interaction of geological, hydrological, and biological processes Formed by features and conditions that exhibit an organizational pattern that persists and are repeatable in a system elements that are essential to maintain a renewable resource The Lake Erie ecosystem co-evolved and has adapted to these structural habitats Peters and Cross (1992)

5 Fundamentals - Aquatic Habitat Combination of a range of physical characteristics and energy conditions that can be delineated geographically that meet the needs of a specific species and/or biological community for a specific life stage. Created and maintained by physical processes acting along hydrogeomorphic pathways that convey energy, water, and materials to, and through, the lakes.

6 Abiotic (Physical) Characteristics Habitat Substrate (Geology) (Climate) Energy Water Mass (Hydrology) Energy oscillatory and unidirectional flows, shear stress, turbulence. Substrate bedrock, composition, texture, hardness, stability, porosity, permeability, roughness. Water Mass depth, temperature, turbidity, nutrients, contaminants, and dissolved oxygen. Habitat when physical characteristics meet the needs of a specific species or biological community for a given life stage

7 Energy and Water Mass Characteristics are Dynamic!

8 Coastal Margin Zones (Littoral) Shoreward limit: Boundaries High water mark, including the shoreline physical attribute (e.g., beach, breakwall, bluff, etc.) Lakeward limit: Western basin - nearer of 5 m depth contour or 4 km Central & Eastern basins - nearer of 10 m depth contour or 4 km Polygon bounds: Centered on 2nd order or larger river mouths; extending half- way to distance to next river mouth on either side

9 Coastal Margin Zones (Littoral) United States: Available Information Existing surveys of OH nearshore to 4 km distance; Shoreline armoring information (ODNR, USACE Potential Damages Study) QHEI information (OEPA) Nature Conservancy Nearshore Classification Canada: Environmental Sensitivity Atlas information (1:10,000 shoreline & nearshore bottom features) CCIW - Environment Canada (Coakley, Biberhofer, Rukavina, Minns et al.)

10 Nearshore Sediment Distribution Western Lake Erie N Nos70k.shp Bathy Bathymetry (meters) Nearsed Glacial (Till, Glacial Lake Clay) Island Mud Muddy Sand / Sandy Mud Rock Sand Undefined Mil es Kilometers

11 Lake Erie Sediment Distribution N W E S Sand and Gravel Mud Sand and Mud Bedrock Cohesive Clay (Glacial Till) Kilometers After Haltuch and Berkman (1999) Coverages courtesy Canada Centre for Inland Waters, Dr. John P. Coakley

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14 Information Required Important variables include Substrate characteristics (distribution, stability) Kinetic energy (low, medium, high) Water mass characteristics Biota-specific habitat variables (function, life stage) Existence of discrete classes unlikely Adapt classes to specific needs (species, communities, life stage) Aquatic environmental template

15 Coastal Margin (Nearshore) Identify and map bottom substrates Sonar : Sidescan and Swath (acoustic backscatter) Sampling Document changes in substrate distribution Area (m 2 ) Centroids (centers of mass) Change patterns (magnitude and direction, distribution) Evaluate environmental characteristics Substrate classification (infer composition, grain size) Substrate stability

16 Aquatic Environmental Template Requires a dynamic classification system Multiple geospatial data layers 3-Dimensional What are the characteristics or variables that define habitat? (habitat suitability analyses) Water Mass Energy Substrate

17 Regional scale Summary Exhibit an organizational pattern, persist, and are repeatable in a system elements that are essential to maintain a renewable resource Many habitat impacts are cumulative, slow acting, and show effects on a scale not easily detected by the casual observer Local scale Nearshore and Coastal Habitats are Dynamic Energy Substrate Water Mass Characteristics