Wetlands: nature’s unique aquatic systems Allison Parnell Coastal & Wetlands Ecology Lab Texas A&M University at Galveston

A transition zone between land and water bodies; WHAT ARE WETLANDS? A transition zone between land and water bodies; neither “land” nor “water”. Refers to a variety of habitats: Coastal salt marshes Forested swamps Freshwater marshes Brackish (intermediate salinity) marshes Photo: A.R. Armitage 3 distinguishing characteristics define wetlands: Hydrology-presence of water Hydric soils-soils that are anoxic Hydrophytic vegetation

All marshes are wetlands BUT not all wetlands are marshes. WHAT ARE WETLANDS? All marshes are wetlands BUT not all wetlands are marshes. Wetlands can be divided into two main habitats: Marshes-dominated by herbaceous (non-woody) vegetation Example: salt marsh Swamps-dominated by trees Example: Cypress -tupelo swamp Photo: A.R. Armitage Photo: Conservationfund.org

SALTWATER VS FRESHWATER WETLANDS Salt marshes are regularly tidally inundated. Some fully marine (salinity ~32‰). Many are estuarine-where freshwater from rivers or streams mixes with ocean water (Gulf of Mexico water). Estuarine marshes result in brackish salinities (~0.5-30‰). Brackish conditions may be temporary (only after large rain events) or may be constant if nearby source of freshwater (river output).

ARE WETLANDS ESTUARIES? An estuary is defined by Pritchard (1967) as: “a semi-enclosed coastal body of water which has a free connection with the open sea and within which seawater is measurably diluted with freshwater derived from land drainage”.

ARE WETLANDS ESTUARIES? Upper Texas Coast River discharge Salt marsh Tidal flooding Photo: A.R. Armitage Photo: www.galvbayinvasives.org

SALTWATER VS FRESHWATER WETLANDS Swamps remain flooded for extensive period of time and may only dry out occasionally. Occur in low lying areas of floodplains (depressions). Dominant source of water is from overbank flooding or may be runoff from precipitation.

INHABITANTS OF SALTWATER WETLANDS Vegetation: Cordgrass of the Spartina genus most prominent. Smooth cordgrass-low elevation. Maritime saltwort-mid elevation. Indian blanket, Fire wheel-upland elevation. Maritime saltwort Indian Blanket, Fire wheel Smooth cordgrass Photos: A.R. Armitage

INHABITANTS OF SALTWATER WETLANDS Invertebrates: Shrimp, fiddler & blue crabs & oysters. Vertebrates: Waterfowl, wading & shore birds. Variety of fish species. Alligators, bobcats, raccoons, snakes & river otters. Photo: chesapeake-bay.org Photo: flickr.com Photos: A. Parnell Photo: coolcreatureshotplanet.com

INHABITANTS OF FRESHWATER WETLANDS Vegetation: Water tupelo & bald cypress-dominant trees. Water hickory, water locust, black tupelo & many others are common to swamps. Water tupelo Bald cypress Water locust Water hickory Photo: jcho.masgc.org Photo: statesymbolsusa.org Black tupelo Photo: forestryimages.org Photo: aggie-horticulture.tamu.edu Photo: my-photo-gallery.com

INHABITANTS OF FRESHWATER WETLANDS Invertebrates: Variety of insects (flies, beetles, dragonflies & damselflies). Spiders & scorpions. Mollusks-slugs & snails & freshwater bivalves. Vertebrates: Bald eagles, woodpeckers, ducks & wading birds. Variety of reptiles & amphibians. Bats, rabbits, beaver, foxes & deer. Variety of freshwater fish species (gars, catfish, bass & minnows). Photos: C. Nunnally Photo: permies.com Photo: A. Parnell Photo: ecotravel.ctaudubon.org

THE IMPORTANCE OF WETLANDS Ecological: In coastal areas nurseries for estuarine organisms, habitat for migratory birds & spawning & feeding areas for recreational and game fish species. Wetlands support regional biodiversity-threatened & endangered species. Photo: fws.gov Photo: tpwd.state.tx.us Wetland plants help improve water quality & may take up CO₂ from the atmosphere and subsequently influence climate change patterns.

THE IMPORTANCE OF WETLANDS Economic: Coastal wetlands reduce wave energy subsequently reducing flooding and protecting shorelines from erosion. Inland wetlands store floodwaters thus controlling flood damage and erosion and stabilize river flows & groundwater levels. Salt marshes-oyster production, commercial fisheries (>$400 million/year), employ ~30,000 coastal residents , sport fishing ($2 billion/year industry). Swamps-contribute to the timber & crayfish industry.

THE IMPORTANCE OF WETLANDS Social: High biodiversity in wetlands provide fishing, nature tourism (kayaking & boating), hunting & bird watching. Photo: txstate.edu Photo: A. Parnell Photo: bird-watching.purzuit.com

Questions? Photos: A. Parnell