Peatland distibution along a north-south transect in the Mackenzie River Basin in relation to climatic and environmental gradients

Nicholson, Barbara J.; Gignac, L. Dennis; Bayley, Suzanne E.

doi:10.1007/bf00045599

Cited by 17 publications

(10 citation statements)

References 41 publications

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“…Characteristic macrofossils found here are Carex seeds, hyaline roots, brown mosses (Drepanocladus and Calliergon), Sphagnum riparium, S. teres, S. cuspidatum, S. balticum and S. lindbergii, all indicating local wet and permafrost-free fen conditions. S. riparium in particular has been recognized as a collapse scar species (Zoltai, 1993;Nicholson et al, 1996;Oksanen et al, 2001). Our interpretation is therefore that local permafrost degradation in the dry upland forest (zone EL1-I) caused ground subsidence resulting in much wetter, non-permafrost fen conditions in zone EL1-II.…”

Section: Macrofossil Analysis: El1mentioning

confidence: 87%

“…BP), wet fen species such as Carex, Sphagnum riparium, S. teres, S. cuspidatum and brown mosses started to appear, suggesting ground subsidence following permafrost thawing. Particularly S. riparium has been identified as collapse scar species (Zoltai, 1993;Nicholson et al, 1996;Oksanen et al, 2001). The sequence in EL1 is similar to the succession from forest to sedge/Sphagnum peat characteristic of collapse scars in Alaska today (Jorgenson et al, 2001).…”

Section: Peatland Inceptionmentioning

confidence: 95%

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Long-term stability of permafrost in subarctic peat plateaus, west-central Canada

Sannel

Kuhry

2008

The Holocene

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Long-term vegetation succession and permafrost dynamics in subarctic peat plateaus of west-central Canada have been studied through detailed plant macrofossil analysis and extensive AMS radiocarbon dating of two peat profiles. Peatland inception at these sites occurred around 5800–5100 yr BP (6600–5900 cal. BP) as a result of paludification of upland forests. At the northern peat plateau site, located in the continuous permafrost zone, palaeobotanical evidence suggests that permafrost was already present under the forested upland prior to peatland development. Paludification was initiated by permafrost collapse, but re-aggradation of permafrost occurred soon after peatland inception. At the southern site, located in the discontinuous permafrost zone, the aggradation of permafrost occurred soon after peatland inception. In the peat plateaus, permafrost conditions have remained very stable until present. Sphagnum fuscum-dominated stages have alternated with more xerophytic communities characterized by ericaceous shrubs. Local peat fires have occurred, but most of these did not cause degradation of the permafrost. Starting from 2800–1100 yr BP (2900–1000 cal. BP) consistently dry surface conditions have prevailed, possibly related to continued frost heave or nearby polygon crack formation.

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Section: Macrofossil Analysis: El1mentioning

confidence: 87%

Section: Peatland Inceptionmentioning

confidence: 95%

Long-term stability of permafrost in subarctic peat plateaus, west-central Canada

Sannel

Kuhry

2008

The Holocene

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“…6 Permafrost tundra includes high‐center polygons, low‐center polygons, tundra with more than 30 cm of organic soil, and polygonal peat plateaus. In polygons, the plant macrofossil assemblages reflect vegetation differences that are generally controlled by microtopography and relative water table position [ de Klerk et al , ; Ellis and Rochefort , ; Nicholson et al , ; Vardy et al , ]. Microtopography and polygonal patterns develop over many centuries with ice wedge and permafrost aggradation [ Mackay , ].…”

Section: Methodsmentioning

confidence: 99%

“…Changes in peat chemistry or peat properties, such as C/N ratios, have been used to aid in the identification of permafrost aggradation within a core [e.g., Sannel and Kuhry, 2009], but it is unknown whether permafrost widely affects peat properties. An abrupt transition from dry hummock bog species to wet fen or bog species can be used to indicate permafrost thaw [Camill et al, 2009;Jones et al, 2013;Myers-Smith et al, 2008;Nicholson et al, 1996;Oksanen et al, 2001;Robinson and Moore, 2000;Zoltai, 1993Zoltai, , 1995. Plant macrofossil records show repeated cycles of permafrost aggradation and thaw over the past several thousand years [Jorgenson et al, 2013;Kuhry, 2008;Oksanen et al, 2001Oksanen et al, , 2003Sannel and Kuhry, 2008;Zoltai, 1993] in some records, but it is unclear how widespread these aggradation-degradation cycles are.…”

Section: Introductionmentioning

confidence: 99%

Effects of permafrost aggradation on peat properties as determined from a pan‐Arctic synthesis of plant macrofossils

et al. 2016

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37Permafrost dynamics play an important role in high-latitude peatland carbon balance and are key 38 to understanding the future response of soil carbon stocks. Permafrost aggradation can control 39 the magnitude of the carbon feedback in peatlands through effects on peat properties. We 40 compiled peatland plant macrofossil records for the northern permafrost zone (515 cores from 41 280 sites) and classified samples by vegetation type and environmental class (fen, bog, tundra 42 and boreal permafrost, thawed permafrost). We examined differences in peat properties (bulk

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“…Quadrat size and sampling design varied as follows: randomly placed quadrats (25 cm × 25 cm) along a transect bisecting each plant community on a peatland (restricted random) Chee and Vitt 1989); 0.5-m 2 circular restricted random (Nicholson et al 1996;L.D. Gignac, unpublished data;L.…”

Section: Vegetation Samplingmentioning

confidence: 99%

Distribution and habitat niches of 37 peatland Cyperaceae species across a broad geographic range in Canada

Gignac¹,

Gauthier²,

Rochefort³

et al. 2004

Can. J. Bot.

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The presence and absence of 37 Cyperaceae species found on 498 peatlands across Canada were examined along surface water chemistry, shade, height above the water table, and climatic gradients. A canonical correspondence analysis of the species distribution along the environmental gradients indicated that surface water chemistry and climate were highly correlated with the first and second axes and were the two most important gradients distinguishing among groups. The climatic gradient was further subdivided into western oceanic continental and eastern oceanic continental gradients. Height above the water table and shade were correlated to the third canonical correspondence analysis axis and were of secondary importance in explaining species distributions. A TWINSPAN analysis of the species separated them into eight groups: (1) widespread, obligate rich fen, wet, shade-tolerant species; (2) widespread rich fen preferential species; (3) continental and eastern oceanic, rich fen preferential, wet, shade-intolerant species; (4) widespread fen, wet, shade-intolerant species; (5) widespread bog or fen, shade-tolerant species; (6) widespread subcontinental and oceanic, bog or fen, shade-intolerant species; (7) eastern subcontinental and oceanic, poor fen preferential species; (8) western oceanic, bog and poor fen preferential, shade-intolerant species. Response surfaces were generated by quantifying the frequency of occurrence of representative species in each group along pH and height above the water table, shade and mean annual temperature, and mean annual total precipitation gradients. Frequency of occurrence values for several of the rarer species indicated that they were not limited by the number of suitable habitats analyzed in this study but by other factors such as competition, failure to establish, or dispersal. This study emphasizes the importance of habitat and climate in determining the local and regional diversity and distribution of the most common Cyperaceae on peatlands in Canada.

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Peatland distibution along a north-south transect in the Mackenzie River Basin in relation to climatic and environmental gradients

Cited by 17 publications

References 41 publications

Long-term stability of permafrost in subarctic peat plateaus, west-central Canada

Long-term stability of permafrost in subarctic peat plateaus, west-central Canada

Effects of permafrost aggradation on peat properties as determined from a pan‐Arctic synthesis of plant macrofossils

Distribution and habitat niches of 37 peatland Cyperaceae species across a broad geographic range in Canada

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