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Wetlands. Ch. 8, Ch. 9, Ch. 10 through page 165. Florida’s Diverse Wetlands. Historically, wetlands were viewed as hostile and nasty - “swamp,” “quagmire,” “fen” - portrayed as mosquito- and snake-infested wildernesses that can swallow unwary travelers
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Wetlands Ch. 8, Ch. 9, Ch. 10 through page 165
Florida’s Diverse Wetlands Historically, wetlands were viewed as hostile and nasty - “swamp,” “quagmire,” “fen” - portrayed as mosquito- and snake-infested wildernesses that can swallow unwary travelers Before European settlement, most of Florida was wetlands
Florida’s Diverse Wetlands Soil is permanently or frequently wet Plants must be specially adapted – if the soil is saturated, oxygen can’t get to the roots - upland plant roots will rot Thus, wetlands can be recognized or defined by their plant species.
Florida’s Diverse Wetlands • Types of wetland: • Marsh – dominated by grasses and forbs (low plants) • Shrub bogs – dominated by low woody plants • Swamps – wetlands with trees
Marsh Swamp Shrub bog
Florida’s Diverse Wetlands • Factors that affect the type of wetland: • topography – the lay of the land • hydroperiod – when and how often it floods, and how deep the water gets • fire frequency – marshes often burn, swamps almost never
Florida’s Diverse Wetlands Wetland delineation: Wetlands in FL and elsewhere are protected by law, since they are such a vital part of the ecosystem. People can be trained in wetland delineation, so that they can legally define what is or isn’t a wetland.
Florida’s Diverse Wetlands • Wetland delineation: • Just because the land is currently dry doesn’t mean that it’s not a wetland. • Professionals look for: • hydric soils • signs of water in the recent past • plants that only grow in wetlands – obligate wetland plants
Benefits of wetlands • Purifying water • As water flows from upland towards lakes and rivers, the wetland plants capture contaminants and take them up into the plant structures • Wetlands also remove and recapture nutrients in the water, so that they don’t all flow away
Benefits of wetlands • Water capture • Basin wetlands capture rainwater and give it a chance to seep back into the ground, recharging the aquifer • The Green Swamp
Benefits of wetlands • Water slowing • Floodplain wetlands slow down floodwaters and thus make flood less extreme • 10% wetland leads to 60% flood reduction; 20% wetlands can mean up to 90% flood reduction • Wetlands are like sponges – soak up water when there is too much, release it slowly during a drought
Benefits of wetlands • Climate control • Organic material (peat and muck) builds up under wetlands; this keeps carbon out of the atmosphere • Wetlands also add to the humidity of an area
Benefits of wetlands • Productivity • Wetlands turn sunlight into plant material at a high rate; that material is then available to feed other organisms • “wetlands generate wildlife”
Wetland Types • Two we will cover (there are more): • Seepage wetlands – water flows across them from a shallow aquifer • Still-water marshes – water is not flowing, or flows very slowly
Seepage Wetlands • Water from the ground flows down a gentle slope • Water is nutrient-poor and very acidic • A seepage wetland could be a marsh, shrub bog, or swamp, or a series of all three • Fire is needed to keep a marsh from turning into a shrub bog
Seepage Wetlands • Water will only flow across the surface if there is an impermeable layer (hardpan) underneath • Because of the gradual change in moisture levels, seepage herb bogs (marshes) are extremely diverse in plant species • There are also many rare species (Panhandle Lily)
Seepage Wetlands • Because conditions are nutrient-poor and acidic, only plants that are specially-adapted to seepage wetlands will survive • “Normal” plants will be stunted • Being carnivorous is a adaptation that allows plants to thrive in seepage bogs
Seepage Wetlands • Pine Barrens Tree Frog • Only exist in three sites: FL panhandle, Carolinas, and Pine Barrens of NJ • Eggs can only develop in cold (68-72o), clear, acidic puddles
Seepage Wetlands • Besides seepage bogs (marshes), other seepage wetlands include: • Seepage shrub bogs • Seepage bay swamps • Seepage white-cedar swamps • These all could exist downslope of the seepage marsh
Seepage Wetlands • Seepage shrub bogs • thick, shady, no groundcover • diversity is low • small, glossy, leathery leaves to help them cope with periods of drought • infrequent hot crown fires • dense thickets provide good cover for mammals like bear and deer
Seepage Wetlands • Seepage bay swamps • trees growing in saturated peat • mostly sweetbay, loblolly bay, and swamp bay • again, leaves are thick and glossy to withstand drought; shade is thick • fires only occur 1-2X per century
Seepage Wetlands • Seepage white-cedar swamp • a rare habitat • white cedar is very disease-resistant, grows slowly, but can grow 100 ft tall and can live for 200+ years • a few huge ones can reach 15 ft diameter • these swamps often harbor plants that are typically found farther north
Stillwater Marshes Much of Florida is flat; water will pool in these spots whenever rainfall exceeds evapotranspiration In some cases, water flows very slowly through a wetland; some of these wetlands will also be mentioned here
Stillwater Marshes • The key characteristic of a stillwater marsh is that water rises and falls with the seasons • the hydroperiod of each marsh is different • marshes that actually become dry for part of the year can be invaded by trees; they will need fire to keep open
Stillwater Marshes • Plants from seepage wetlands never dry out, but stillwater marsh plants have to cope with a dry period • thick, shallow roots crowd out woody plants and allow marsh plants to die back in dry season • adaptations to keep leaves/flowers above water • can burn even over standing water
Stillwater Marshes • The types of plants found in a marsh depend on its hydroperiod • if a marsh is flooded for 70% of the year, you will find different plants than if it is flooded for 95% • marsh plant species don’t vary much between north and south FL
Stillwater Marshes • Periphyton: microscopic algae that coat every underwater surface in a marsh • basis for marsh food chain • close to 300 microscopic species eat the periphyton, and then become prey for larger species • insects and other invertebrates, frogs, salamanders, snakes, turtles • key habitat for wading and water birds, especially in winter
Stillwater Marshes • Wood stork: • federally endangered bird • dropping water levels trigger nesting • if water drops too much or not enough, they won’t be able to raise chicks successfully • also need large, sturdy trees for nests
Stillwater Marshes • Types: • Depression or basin marshes • Wet flats • Marl prairies • Swales and Sloughs
Stillwater Marshes • Depression or basin marshes • water pools in a shallow depression • dry for part of the year – temporary or ephemeral wetland • no fish, so critters that lay eggs in water depend on these wetlands for reproduction • different species breed in different seasons
Stillwater Marshes • Wet flats • broad, flat, wet areas • diverse, b/c of small changes in elevation/wetness • burrowing crayfish (up to 20 species) are considered to be keystone species • turn up soil so seeds can germinate • small burrows are home to many small animals
Stillwater Marshes • Marl Prairies • only in south FL • marl is a soil made of periphyton and calcium carbonate; crumbly and very alkaline • only specific plants can live there – it’s difficult to tolerate the low nutrients and high alkalinity
Stillwater Marshes • Swales and Sloughs • not truly stillwater; water flows very slowly • a swale is a “depression between ridges” • a slough is a channel of deeper water in a wetland • technically, the Everglades is a vast swale