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GEOLOGY,

HYDROLOGY AND FW

HABITATS (CH. 4)Introductory Comments

Continuity of FW Habitats

How are FW habitats defined?

Geology (geomorphology)

Water movement through the environment

hydrologic cycle

How that movement varies spatially and

temporally hydrodynamics

Links between terrestrial and aquatic

environments and between different aquatic

ecosystems

FIGURE 4.2

The Hydrologic Cycle

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WETLANDS (CH. 5)

Interfaces between Terrestrialand Aquatic Ecosystems

Defining Wetlands Synonyms: swamps, bogs, marshes, potholesetc.

Ecotone transitional habitat; terrestrial andaquatic species

Can contribute to high biodiversity

Key defining features:

Shallow water or saturated soil (hydric)

Distinct plant life hydrophytes; emergentmacrophytes and trees; floating vegetation

Organically-rich soil that differs from surroundinguplands

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Global Distribution of Wetlands

Climate and geomorphology

Wetlands are more prevalent in cool and wet

climates than in hot and dry Cool climates less loss to evapotranspiration

Wet climates excess precipitation

Steep terrains have fewer wetlands than flat,gently-sloping landscapes

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Most Endangered Aquatic Habitat

70% of U.S. riparian wetlands lost

50% of prairie potholes gone

Half of Everglades drained

22 states have lost more than half of theirwetlands in the last 200 years

Kansas: only 48% remain

Wetlands lost in other countries: Cameroon(80%), New Zealand (90%), Australia (95%),Thailand (96%), Vietnam (>99%)

No Net-Loss Policy attempt at mitigation

The Reclamationof the MississippiDelta

What are some Services provided by

Wetlands?

Critical components to watersheds

Recharging water supplies

Stabilize shorelines, retaining sediment andreducing erosion

Water filtration purifies water, chemical sink

Carbon sinks 400-500 Gt

Flood control slows run-off; water storage

Maintain biodiversity larger the better

Consumer goods

Recreation

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Coastal Wetlands

Mangroves (subtropical totropical)

Halophytic mangrove trees Low wave action and high

sedimentation rates

Anoxic sediments; many species have

pneumatophores

Above and below the water habitats diverse

assemblage of invertebrates and vertebrates

Export lots of production to open waters as detritus

Inland Wetlands

Marshes; swamps; riverine or riparian wetlands;peatlands

Riverine, fringe and depressionalgeomorphologies

U.S. Marshesdominated by emergentvegetation whereas swampsby trees

Inland marshes and swamps most extensivetype of wetland worldwide

Freshwater Marsh (worldwide)

Diverse wetlands; grasses, sedges and otheremergent hydrophytes; floating plants

Very productive and diverse

Prairie potholes; Everglades; Great Lakes

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Riparian/Riverine Wetlands (worldwide)

Wetlands along rivers; floodplains of large rivers

Range from seasonal to permanent inundation

Exchange of nutrients and energy betweenfloodplain and river channel

Inundated floodplains as nursery grounds

Peatland (Northern Wetlands)

Cool temps low rates of decomposition

Accumulation of decaying organic matter

Bogs little or no water flow; precipitation only

Acidic soils predominance of Sphagnummoss

Fens inputs from runoff and groundwater

Support a wider range of plant species

Holds 1/3 of soil carbon Where is most of thewarming taking place?

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Wetland Hydrology: Master Variable

Water depth, flow patterns, duration andfrequency of flooding and flushing

Influence biochemistry of water and soils Ultimate selection of wetland biota

Water sources and hydrodynamics

Precipitation standing water; low water

movement; subject to anoxia

Surface water episodic flooding and flushing;

extended periods of standing water

Groundwater constant flow and flushing

Hydrology and Nutrient Input

Wetlands range from eutrophic to oligotrophic

Surface-water sourced floodplain andlandscape inputs diverse plant communities

Groundwater-sourced constant input of flowand nutrients stable communities

Precipitation-sourced little nutrient input; lowproductivity and diversity

Together with variation in salinity, pH and otherchemical parameters strong determinant of

plant community

Okavango Delta