Peatland Bryology

Define Peatlands

An area of naturally accumulated peat layer at the surface

• organic layer accumulates cause production > decomposition

What kinds of peatlands are there?

Bogs and Fens

What are the ecological values of peatlands

• wildlife habitat

• home to 25% of provincial flora

• controls local hydrology

• carbon sink

• natural filter system

What are the 5 classifications of peatlands

1. shallow open water - intermittent water

2. marsh - treeless with large seasonal h20 fluctuations

3. swamp- marsh but treed

4. fen - water (ground water specifically) flows through

5. bog - precipitation driven (all water and nutrients from precip)

What does Ombrotrophic mean?

All water and nutrients come from precipitation (i.e. bogs)

Which of the 5 types of wetlands are bryophyte dominated?

Fens and Bogs- Bogs are specifically sphagnum dominated

What are the 5 types of peatlands in Alberta?

1. Treed bogs- water flows away from centre, sphagnum dominated (hummocks), black spruce ericaeous shrubs

2. Poor fens- carpets of sphagnum

3. Medium rich fens- brown moss dominated

4. Extremely rich fens - also brown moss dom

5. Plateau bogs - underlaid by permafrost

In Alberta, where do all bogs come from?

Fens

What are the steps for bogs to develop in AB?

1. carex dominated fen w/ mineral water flowing through

2. carex peat accumulates over time, reaching level of water table

3. once water table is reached, sphagnum can establish

4. once established, sphagnum acidifies the water and sphagnum peat accumulates well above water table

5. This leads to drier conditions, allowing black spruce to establish and hence, ombrotrophic bogs

What is the earliest record of sphagnum dominated peatlands?

8-10 thousand years ago, with extensive peatlands development by 4-6 thousand years ago

What is peat?

Spongy material formed by the partial decomposition of organic matter/Vegetation

What are some indicators for a Bog

Sphagnum fuscum

Sphagnum capillifolium

Sphagnum magellanicum

What are some indicators for Poor fen

Tomentypnum falcifolium

Sphagnum riparium

Drepanocladis exxannulatus

What are some indicators for moderately rich fens

Calliergon cuspidata

Sphagnum teres

Drepanocladus aduncus

What are some indicators for extremely rich fens?

Drepanocladus revolvens

Campylium stellaum

Scorpidium scorpiodes

What is the minimum amount of peat accumulation to constitue a fen?

40cm

What is an acrotelm?

A layer of living vegetation above mean water table

How much sphagnum moves from the acrotelm to the carotelm (dead layer below acrotelm) per year?

10-42% per year- unique rate for each species

List some uses of peat

• peat moss for horticultural use

• Alcohol

• Industrial absorbent products

• heating

• sanitary napkins/surgical dressing

• bathing products

What percentage of alberta is peatland?

16.3 %

How much of peatlands are harvested annually? and how much peat is removed?

0.02% of peatlands in canada are harvested annually, removing 1.2 million metric tonnes

Is peat harvesting problematic?

Not yet, accumulation rate is 60 times that of what is harvested

However, peatlands are finite and declining due to climate change, and our demand for peat is increasing

What are the steps for harvesting peat?

1. clearing trees

2. ditching to drain water

3. harvesting peat- loosening surface, picking sticks, vacuuming peat

4. preparing peat for sale

What are the goals of peatland restoration?

Re-establishing plant cover (i.e sphagnum domination)

Re-wetting harvested sites by raising and stabilizing water table near the surface

What are the main challenges to peatland restoration?

Harvest occurs until fen peat is reached which changes the water chemistry drastically and its hard to change back

Hydrological regime is altered (peatlands drained, then water level re-raised after)

What are the water availability challenges?

1. post-harvest site is sterile: no plants or diaspores, exposed conditions

2. Drainage of petland dries out peat : too dry for plant colonization

3. Removal of acrotelm: leaves just catotelm layer (compressed and does not have high water storage capacity)

What are the flooding challenges?

• flooding occurs with initial drainage, storm events, rapid snow melt

• increases final capitula production of 10 spahgnum species but reduces dessication tolerance of the plant

• Generally more of an issue in eastern Canada and Europe

How do you fix the problem of surface loss through oxidation and erosion after harvest?

re-wet site and vegetate, maintain catotelm

How do you fix the problem of frost heaving and an unconsolidated substrate (unsuitable for establishment)?

Companion planting with mulch

Managing number of freeze and thaw cycles (how??)

Planting species that uptake water to reduce that available for freezing in the substrate (ie. Polytrichum strictum)

What are some of the other considerations of restoration?

• end use goals of land owners and other parties

• adjacent land still in production

• infrastructure

• peat “overburden” removed and exposes mineral soil- facilitates invasive species establishment, area no longer a peatland/bog

• Fundamental alteration of prevailing climatic conditions- area may no longer be suitable for peatland, lacking precipitaion

Why are alternative reclamations used in western alberta and what are some options?

Sites may not turn back into a peatland after harvest so other land uses may be considered

• timber production

• fuel cropping

• berry farming

• agriculture

• wetland creation

• pulp production