Tropical Ecology - John Geiger - FIU - Exam 3 - Chapter 7: Wetlands & Succession

What are wetlands?

"kidneys of the landscape", "ecological supermarkets" and "mosquito-infested mudholes".

What's included on the wetland's definition of the RAMSAR convention of 1971?

lakes, rivers, floodplains, mangroves and even coral reefs.

What are Wetlands?

areas that are permanently/seasonally flooded with fresh water, comprising mosaic of vegetated areas and open, shallow water areas.

What are Wetlands?

- transitional zone between wet and dry areas.

- very diverse, but characterized by the presence of water, soils are different from surrounding catchment, plants are mostly hydrophytes (Water loving plants)

Wetlands occupy

occupy 6% of Earth's surface; important in Tropics.

3 Major Categories of Wetlands

1. floating Sudd communities

2. permanent/seasonal herbaceous swamps

3. swamp forest

Sudd:

- mats of floating vegetation

- applied to mats of Cyperus papyrus adjacent to upper Nile in Sudan

- mats so well developed, people can walk on them

Floating vs. Rooted

Typha (above ground biomass) and Sediment (below ground biomass) vs. Cyperus papyrus (aerial biomass) and Sediment (sludge)

Rooted Swamps of Lake Chilwa

shallow, saline lake east of African Rift Valley in Malawi

2 Types of Herbaceous Wetlands

1. those dominated by floating "islands" of vegetation

2. those dominated by rooted plants (i.e. Typha d. or Phragmites k.)

Swamp Forests

well developed in Malasia, SE Asia and Congo Basin

Okavango Wetland

Okavango River in North Botswana flows into Kalahari desert, creating the Okavango Delta

Ecological Succession:

predictable sequence with one plant community replacing another

Primary Ecological Succession:

occurs on bare sites

Secondary Ecological Succession:

takes place on land previously vegetated

List of Primary Ecological Succession (examples):

- glacial retreat

- roads

- gravel pads in tundra

- strip mines

- sea cliff

- landslides

- volcanic islands

- colonization of lava fields

- bog succession

Okavango Wetland

4,000 km^2 permanent wetlands, up to 12,000 km^2

Okavango Wetland

96% of water lost via transpiration, 2% via Boteti R.

Okavango Wetland

1300 plants species; 444 bird species; & 122 mammals

Okavango Wetland

most island formation via termites, create 4 meters mounds that may turn into high diversity island forests

Sudd Communities of Lake Naivasha

shallow lake in Kenya with NO outflow (i.e. it is endorheic)

Sudd Communities of Lake Naivasha

unusual, natural lake that fluctuates seasonally and is fresh water

Sudd Communities of Lake Naivasha

significantly altered by: eutrophication, swamp clearing for agriculture, and exotic species

Rooted Swamps of Lake Chilwa

surrounded by ~600 km^2 of wetlands, mostly Typha domingensis; grow 2-3 meters above water

Rooted Swamps of Lake Chilwa

completely dried down in 1968; refilled again in 1969

Rooted Swamps of Lake Chilwa

27 species of fish, mostly r-selected strategies

Rooted Swamps of Lake Chilwa

important habitat for waterfowl; 160 species

Rooted Swamps of Lake Chilwa

as other wetlands, si. water level fluctuations

How different are the 2 types of Herbaceous Wetlands

- both types differ functionally and structurally

- nutrient cycling in sudd: nutrients absorbed by plants from water column; material accumulates as sludge beneath mats

- nutrient cycling by Typha d.: nutrients into sediments and then, absorbed by plants via roots

Autogenic

plants and animals genesis of change

Allogenic

plants and animals respond to changing climate/topography

Secondary Ecological Succession (example):

field to forest

Herbaceous wetlands

wetlands are best considered as aquatic systems

Herbaceous wetlands

the autotrophic layer on top of heterotrophic layer

Herbaceous wetlands

food web split: primary production in air and secondary production/decomposition occurring in water

Herbaceous wetlands

very little Photosynthetically Active Radiation (PAR) reaches water surface

Herbaceous wetlands

low dissolved O2 concentrations in water

Herbaceous wetlands

wetlands are highly productive with C4 plants

Herbaceous wetlands

wetlands plants efficient at holding on to nutrients; nitrogen removal slows eutrophication

Herbaceous wetlands

few herbivores, most net PP becomes detritus

Swamp Forests

Relatively species poor; scattered trees with grassy areas that become flooded in wet season

Swamp Forests

large areas of peat swamp forest in Kalimantan Indonesia (Island of Borneo); plants have pneumatophores, adventitious and stilt roots

Peat

soil type with high organic matter; derived from woody plant parts that are slowly decomposing

Swamp Forests

Topogenous vs. Ombrogenous

Ecological Succession

process of directional change in plant/animal life in an area leading to an approximately more stable community, climax community

Sere

one stage, of many, in succession

Different filters determining community development

dispersal, physiological, and biotic

Establishment of Ecological Succession

not only germination, but survival

Ecological Succession

plants (autotrophs) colonize first, then animals

Ecological Succession

plants create conditions that allow for colonization of other species (facilitators)

Ecological Succession

as environment "fills up" with species, competition increases and community development is balance between facilitation and competition

At the end (climax community)

ONLY good competitors are able to survive

Why might be a good idea to create a wetland buffer between the EAA and the Everglades? Name possible outcomes in terms of nutrients and water quality.

Eutrophication. A buffer zone would be a shield for nutrients runoff from the farm lands. This would prevent algal blooms which kills fish and other water animals and plants