Biol 333: Lecture 2: Wetland Science + Definitions

What are three different values systems for defining wetlands?

1. Political // Economic

2. Conservation goals

3. Science

What are some supports for wetland science as a seperate science?

→ Research and management required an interdisciplinary approach

→ Wetlands have unique properties, not adequate covered by other disciplines (not transitionary)

→ Distant wetlands display similarities no matter how far

→ Sound policy making required strong scientific under pinning

What are some challenges to wetland science?

• Wetland creation and restoration

• Wetland conservation

• The role of wetlands in global biogeochemical cycles

• Impacts of climate change on wetland functions + biodiversity

• Wetland mapping

• Tropical wetlands

What are three defining characteristics of wetlands?

1. Persistence of water; either at or above the ground surface or within the root zone

Periodic saturation / inundation sufficient to influence ecosystem; Standing water shallow enough to not have lake characteristics

2. Unique soil conditions / different from adjacent uplands (hydric soils)

Accumulation of organic matter, formation of peat due to anoxia; Gleyed mineral soils due to anoxia

3. Vegetation adapted to wet conditions (hydrophytes) and absence of flood-intolerant biota

What are 6 difficulties and delineating wetlands?

1. Inter/Intra Annual seasonality of flooding

2. Ecotone transitions

3. Hydrophyte vegetation

4. Wetland scale

5. Geography/Location of wetland

6. Human disturbance + time scales

What are the two main catagories of vegetation in wetlands?

1. Obligate species = almost always only occur in wetlands

2. Facultative species = occur in wetlands and non wetlands

What is the Canadian Wetland Definition?

Land that is saturated with water long enough to promote wetland or aquatic processes as indicated by poorly drained soils, hydrophytic vegetation and various kinds of biological activity which are adapted to a wet environment

Organic soil wetlands have >40 cm peat

Mineral soil wetlands have ~ 2m standing water

How do legal definitions differ from scientific definitions?

Not much different than scientific definitions but they include qualifiers

What are the general characteristics of shallow water wetlands?

• < 2 m standing vegetation

• < 25% emergent vegetation

What are the general characteristics of freshwater marsh wetlands?

• >25% emergent vegetation

• Absence of woody vegetation

What are the general characteristics of freshwater swamps?

• Closed canopy of woody vegetation; shrubs or trees

• Can form peat or be mineral soil

What are the general characteristics of fens?

• >40 cm of peat (poorly decomposed at surface)

• Groundwater connection (pH >4.8)

• Can have open canopies of stunted trees

• Mosses (true and sphagnum), graminoids and shrubs common

What are the general characteristics of bogs?

• >40 cm peat

• No groundwater connection (pH 3.8-4.8)

• Can have open canopies of stunted trees

• Usually dominated by sphagnum mosses

Who needs accurate definitions of wetlands?

policy makers, managers, scientists and the general public

What is the Alberta Wetland Definition?

“Wetlands are lands saturated with water for long enough to promote the formation of water altered soils, growth of water tolerant vegetation and biological activity adapted to a wet environment

How are wetland boundaries defined in Alberta?

The furthest ecological extent of a wetland bordering upland or other non-wetland habitat, as indicated by a shift from hydric to non-hydric soils and facultative wetland vegetation in the majority of years. The wetland boundary is delineated by the absence of wetland soil and vegetation indicators.