Wetlands of the Middle Peninsula
Karen Duhring Virginia Institute of Marine Science
September 7, 2019 Gloucester Master Gardeners
Robins Neck – Lands End WETLAND
What’s the first thing that comes to mind? Salt Marsh
Johns Point Landing - Naxera Mud Flat
Clapper rail Freshwater Marsh
Pamunkey River Freshwater Marsh Freshwater Ponds & Lakes Swamp
A wetland dominated by trees
Dragon Run Seepage Swamp
Elevated Water Table Below Ground Phragmites australis Roadside & Other Ditches Farm Field Wetland Mowed Marsh Engineered Wetland
Johns Point Landing Living Shoreline Middle Peninsula Wetland Acres All Types
Wetland Acres % County Area* Mathews 26,207 47%
Gloucester 38,553 27%
King William 30,374 17%
King & Queen 24,527 12%
Middlesex 10,027 11%
*2010 land cover
Source: NOAA Coastal County Snapshots – Wetland Benefits Hydrology: Water Sources in Wetlands
Rain – Surface Runoff
Groundwater Springs or Seepage
Tides Salt & Fresh Middle Peninsula Wetlands Classified by Vegetation Groups that Recur on the Landscape
Palustrine • Coastal Plain Bottomland Forests non-tidal wetlands dominated by • Wet Flatwoods woody plants and herbaceous emergents • Semi-permanent Impoundments (beaver ponds, reservoirs, mill ponds)
Estuarine • Tidal hardwood swamps (unique) tidal wetlands extending to upstream limits • Tidal shrub swamps of tidal influence • Tidal Freshwater Marshes < 0.5 ppt Includes both salt & fresh water • Tidal Oligohaline Marshes 0.5-5 ppt tidal wetlands • Tidal Mesohaline 5-18 ppt • Tidal Polyhaline Marshes 8-30 ppt • Tidal Flats (not vegetated)
Source: Natural Communities of Virginia version 2.6, VA DCR Wetland Landscape Positions
Different plant communities Non-Tidal Freshwater Wetlands Non-Tidal Head of Tide Inland extent of tidal influence
Tidal
Tidal Freshwater < 0.5 ppt Tidal Tidal Freshwater Saltwater Wetlands Wetlands Oligohaline 0.5 – 5 ppt Tidal Saltwater Mesohaline 5 - 18 ppt Wetlands
Polyhaline 18 - 35 ppt
Ocean Virginia Wetland Types based on water feature & vegetation
Tidal
Non-Tidal National Wetlands Inventory
Mobjack Bay
Source: U.S. Fish & Wildlife Service National Wetlands Inventory Wetland Locations Are tidal & non-tidal wetlands separated?
Belle Isle State Park Wetland Locations Are tidal & non-tidal wetlands separated? Sometimes but not always & boundaries are not distinct
Non-Tidal Tidal
Belle Isle State Park Connected Wetlands Tidal & Non-Tidal
Tidal
No distinct boundaries
Non-Tidal Gradual changes in Headwater Wetlands vegetation zones moving up or downstream Isolated Non-Tidal Wetlands Surrounded by Upland
Tend to be avoided by roads & farms
Divided by utility easement in this example
Source: National Wetlands Inventory Large Non-Tidal Wetland Areas on the Middle Peninsula
• Dragon Run • Central Mathews County • Robins Neck • Coleman Swamp
What’s in the red circle? Woodville Park National Wetlands Inventory – Mathews Co.
Tidal
Non- Tidal
Source: National Wetlands Inventory http://www.fws.gov/wetlands WETLAND ECOSYSTEM SERVICES Fish & Wildlife Habitat Diversity
Eastern diamondback terrapin uses both wetland and terrestrial habitats
Great blue herons & other birds find food Monarch butterfly on swamp and shelter in tidal and non-tidal wetlands milkweed
Juvenile blue crabs & fishes are found in high numbers in salt marshes, incl. croaker, spot, speckled trout, striped bass, flounder Mallard duck nest in tidal marsh Threatened and Endangered Species Habitat
Up to 43% of federally threatened and endangered species rely directly or indirectly on wetlands for their survival U. S. Fish & Wildlife Service
Black Rail Food Web Links Benthic animals in wetlands that live on or under the soil provide critical food web link between non-vegetated wetlands and other habitats
Blue Crab at High Tide Clapper Rail at Low Tide
Jenny Dreyer, VIMS Common Clamworm Amphipods Stout razor clams Economic Benefits – Commercial Fishing
2013 Jobs Output from Revenue from Reports Businesses Self-Employed Gloucester 140 NA $5 million Mathews 70 NA $4.5 million Middlesex 66 $2.6 million Many commercially important fish species depend on wetlands during their life cycle Water quality improvement Food
Shelter Atlantic menhaden Brevoortia tyrannus
Source: NOAA Coastal County Snapshots Cultural: Aesthetics & Recreation
The quality of life in coastal communities is enhanced by the beauty and recreation opportunities provided by wetlands.
Property values are affected by aesthetics & natural beauty of coastal wetlands. Ecotourism contributes to the local economy. Pollution Regulation Water Quality Processes
Wetlands filter & detoxify runoff from residential, agricultural, & urban areas
• Nutrient uptake & conversion
• Sediment trapping
• Oxygen production
• Soil adsorption & adhesion
• Soil microbial activity Flood Regulation
Wetlands reduce flood crests and flow rates after rainstorms
Higher flood crests and higher flows
Lower flood crests and lower flows
WETLANDS FLOW RATE FLOW FLOOD HEIGHT FLOOD
NO WETLANDS Erosion Regulation – Tidal Waters & Storm Surge
Tidal wetlands can dissipate up to half normal wave energy within the first 3 meters of marsh grass (+ 10 ft) Greenhouse Gas Regulation Carbon sequestration – Blue Carbon Wetlands store carbon within live and preserved (peat) plant biomass. Wetlands help moderate global climate conditions.
Dameron Marsh THREATS TO WETLANDS Virginia Wetland Status Estimated 50% loss of pre-colonial wetland acreage Mostly due to land use conversion to uplands especially development & shoreline hardening Approximately 1 million wetland acres remain in VA – 75% non-tidal + 25% tidal
Source: Comprehensive Wetland Program Plan, Commonwealth of Virginia Wetland Stressors Conversion to Other Uses
• Timber harvesting • Filling • Routine mowing & grazing • Roads & railroads • Excessive nutrients • Shoreline armoring • Herbicide application
Mowed salt marsh Bulkhead prevents salt marsh migration Wetland Stressors Hydrologic Alterations
• Diversions • Dikes & dams • Stream channelization • Dredging & drainage • Ditching • Point source discharges
Divert or prevent water from reaching wetlands resulting in a change or in type or possible conversion to upland Invasive Plants that may occur in Coastal Plain Wetlands
Alligator weed Alernanthera philoxeroides
Common reed Phragmites Japanese stilt grass Japanese knotweed Lespedeza cuneata Mile-a-minute Purple loosestrife Giant reed Arundo donax WETLANDS & SEA LEVEL RISE Tidal Flooding Increased elevation, frequency & duration
2018 Catch the King Tide citizen scientists mapping a high tide line Coastal Habitat Changes in response to sea-level rise & salt intrusion
Uplands • Shoreline forest to tidal marshes • Back dunes to sand beaches
Wetlands • Non-tidal to tidal • Tidal freshwater to brackish marshes • Low marsh migration into high marsh • Mud flat migration into low marsh Tidal Marsh Migration
Erosion & Loss of marsh is controlled by rates of sea level rise, wave energy, & sediment supply
Sediment accretion is controlled by rates of plant production, decomposition, & sediment sources Migration & Gain of marsh is controlled by elevation, rates of sea-level rise & land use
Source: CCRM-VIMS Rivers & Coast 2016 Marsh migration into upland
Tidal Marsh
Transition Zone
Upland Forest Ghost Forests & Trees Gradual transition over time Many stressed trees blown down during single storm event
Bethel Beach
Naxera WHAT CAN WE DO FOR WETLANDS? Recognize & Protect Remaining Wetlands on both public & private lands
Public conservation lands alone are not sufficient to maintain the desired suite of wetland ecosystem services.
• Identify wetland locations using various tools • Avoid disturbing wetlands • Maintain upland buffers around wetlands Accommodate Tidal Marshes as Sea Level Rises Upland – Wetland Transition Area Let wetland vegetation move and grow where elevations are suitable Selectively remove dead & dying trees stressed by frequent flooding
Upland Salt forest marsh
Marsh Migration Living Shorelines for Erosion Protection created wetland – upland features instead of bulkheads and revetments 2014
2017 Johns Point Landing - Naxera Comply with Wetland Regulations
Permits are required for activities that disturb wetlands Filling, Dredging, Draining, Roads & Bridges, etc.
State law requires ‘No Net Loss’ in wetland amount & function Unavoidable wetland losses must be compensated by: – Creating or restoring wetlands – Purchasing ‘credits’ from approved wetland mitigation banks &/or – Preserving wetland buffers What Master Gardeners Can Do to Help Wetlands
• Learn where wetlands are located near you • Support local parks & natural areas – Ask about wetland restoration wish lists • Help with public education about importance & benefits of wetlands – To minimize impacts by wetland property owners – To encourage compliance with wetland regulations • Learn about native plants for wet soil areas – How to manage gardens and landscapes to co-exist with wetlands Gardening in Wet Soil
• Cease mowing – see what grows • Water root balls thoroughly before planting • Set root ball higher in the soil or on ground surface with created mound • “Butterflying” root ball – sever roots into sections & spread out • Replenish soil around new plantings after floods • Raised beds & container gardens • Rain Gardens do not work in constantly Purchase plants from wet areas wetland nurseries – Look at low zone rain garden plants Native Plants for Wet Soil Trees & Shrubs
Bald cypress Bayberry – wax myrtle River birch Hazel alder Hackberry Buttonbush American holly Chokeberries American hornbeam Clethra sweet pepperbush American sycamore Elderberries Sweetbay magnolia Viburnums Red maple Inkberry holly Oaks Winterberry holly Tupelos Coastal & swamp azaleas Willows Loblolly pine Eastern red cedar Native Plants for Wet Soil Perennials
Beebalm Blue-eyed grass Goldenrods Irises Ironweeds Joe-pye weeds Lobelias - Cardinal flower Marsh hibiscus New York & New England aster Rudbeckia species Solomon’s seal Sunflowers Helianthus species Swamp milkweed Native Plants for Wet Soil Ground Covers – Grasses – Grass Like
Ferns Bulrushes Scirpus species Sedges Carex species Soft rush Sweet flag
Switch grass Little bluestem Northern sea oats WHAT ABOUT PHRAGMITES? Integrated Pest Management
• Correctly identify “weeds” & pests • Increase tolerance for temporary pest damage • Use chemicals only as last resort • Strictly adhere to label instructions • Proper storage & disposal of fertilizers & chemicals – Prevent accidental release during floods Common Reed Phragmites australis (Frag-mite-eez oss-stral-iss)
Complete eradication is difficult in most circumstances Intensive research & multiple control programs across the USA No easy solutions
Tidal marsh with invasive Phragmites australis where nutrient-rich groundwater flows from adjacent high bank Big Cordgrass Common Reed Spartina cynosuroides Phragmites australis
Highly beneficial native grass in same habitats
Leaves arranged on stem in Leaves separated along stem overlapping sheaths, coming off in Broad, acutely tapering leaves (long different directions pointed) Minute upturned teeth along leaf Distinct blue-gray color margins that scratch or cut skin Big Cordgrass Common Reed Grass Spartina cynosuroides Phragmites australis Phragmites Management considerations
• Consider ecosystem services of • Herbicide treatments are erosion and flood protection indiscriminate, beneficial plants can be affected • Extensive removal without replacing these services may Excavation of the rhizome network increase risk to upland • then backfilling with clean sand property may be possible
• Control measures should be site-specific and value-driven • Replacing native plants after control advised • Early detection & prevention encouraged Phragmites Recommended Reading
Phragmites Control Booklet 2008 Virginia Department of Conservation & Recreation Wetlands of the Middle Peninsula Summary • Wetland habitats are located throughout the region & can be recognized by native plant associations • Tidal & non-tidal wetlands are described & regulated separately, but are sometimes connected without distinct boundaries • Wetlands are essential for clean water & productive coastal economy, yet are threatened by many stressors • Both voluntary and regulatory actions can be taken to help protect wetlands
– Many wetland education resources & tools available Thank you for your interest in Wetlands!
Contact Information Karen Duhring [email protected] 804-684-7159