NOTES ON CLASSIFICATION

Transcription

1 The Garry oak rock outcrop and Garry oak savanna or parkland ecosystems contain many of these rare species, such as Aster curtus (white-topped aster), Balsamorhiza deltoidea (deltoid balsamroot), Camassia leichtlinii (great camas), and Castilleja levisecta (golden Indian paintbrush). In addition, many species of a broader southern distribution are restricted to these Garry oak ecosystems in the CDF. These include showy flowers such as Camassia quamash (common camas), Dodecatheon hendersonii (broad-leaved shootingstar), and Sisyrinchium douglasii (satin-flower), which contribute to the beautiful spring floral display of these saanich ecosystems. Encroaching urban development and invasion of the weedy Cytisus scoparius (Scotch broom) are threatening these important and unique ecosystems. Alluvial forests and wetlands are rare in the CDF as a result of urbanization and agriculture. Soils in the CDF are generally derived from morainal, colluvial, and marine deposits. The accumulation of organic materials in semi- to well-decomposed organic deposits is uncommon. Soils are usually Brunisols, grading with increased precipitation to Humo-Ferric Podzols. Zonal soils are mostly Dystric or Eutric Brunisols; the soils developing under Garry oak typically include a melanized (Ah) horizon and are Melanic Brunisols. Humus development is characterized by Moder to weak Mor formation. NOTES ON CLASSIFICATION Krajina (1965) initially recognized dry and wet subzones of this zone. The wet subzone is now classified in the Coastal Western Hemlock zone (Eastern Very Dry Maritime [CWHm1] variant) as a result of a review of information and changes in the methods of classification. Thus, only one maritime subzone of the CDF is now recognized. Variants of this Moist Maritime CDF (CDFmm) subzone have not been identified. With increasing elevation, latitude, and distance inland from the coast, the CDFmm subzone is replaced by the CWHm1 variant. Most of the data for classification of site associations in the CDFmm were collected by Roemer (1972). Additional information and changes in classification concepts over the past 10 years have caused some changes to the classification of ecosystem units. An overview of the current status of some site associations follows. SOME REPRESENTATIVE SITE ASSOCIATIONS These four common site associations represent plant communities that occupy a gradient of soil moisture regimes ranging from very dry to wet and that have not been disturbed for a minimum of 50 years. Topographic position of the site is frequently correlated with this soil moisture regime, allowing site associations to be depicted as in Figure 17. The four site associations listed are not found in any other biogeoclimatic zone. 84

2 Biogeoclimatic Unit CDFmm CWHdm CWHmm1 CWHmm2 CWHm1 CWHm2 39 TREE LAYER SHRUB LAYER HERB LAYER MOSS LAYER Pseudotsuga menziesii Thuja plicata Abies grandis Acer macrophyllurn Cornus nuttallii Tsuga heterophylla Abies amabilis Chamaecyparis nootkatensis Tsuga mertensiana Arbutus menziesii Gaultheria shallon Mahonia nervosa Vaccinium parvifolium Rubus ursinus Rosa gymnocarpa Holodiscus discolor Symphoricarpos mollis Lonicera ciliosa Symphoricarpos albus Chimaphila umbellata Vaccinium alaskaense Acer circinatum Vaccinium membranaceum Vaccinium ovalifolium Philadelphus lewisii Linnaea borealis Polystichum munitum Pteridium aquilinum Trientalis latifolia Achlys triphylla Blechnum spicant Clintonia uniflora Cornus canadensis Rubus pedatus Hylocomium splendens Kindbergia oregana Rhytidiadelphus triquetrus Plagiothecium undulatum Rhytidiadelphus loreus Rhytidiopsis robusta Douglas-fir western redcedar grand fir bigleaf maple western flowering dogwood western hemlock amabilis fir yellow-cedar mountain hemlock arbutus salal dull Oregon-grape red huckleberry trailing blackberry baldhip rose ocean spray trailing snowberry western trumpet honeysuckle common snowberry prince's pine Alaskan blueberry vine maple black huckleberry oval-leaved blue berry mock-orange twinflower sword fern bracken broad-leaved starflower vanilla leaf deer fern queen's cup bunchberry five-leaved bramble step moss Oregon beaked moss electrified cat's tail moss flat moss lanky moss pipecleaner moss TABLE 15. Vegetation table for zonal sites of summer-dry maritime biogeoclimatic units

3 Comments: Grid No. 16 CWHm GENERAL COMMENTS: where recommended on the grid, Lw (on a trial basis), Cw and Pw are alternatives to Fd on sites affected by laminated root rot Lw is recommended on a trial basis as a minor species on dry sites high hazard for Sitka spruce weevil, white pine blister rust, and laminated root rot; moderate hazard for Armillaria root rot SPECIFIC COMMENTS: 01 Hw is an alternative to Fd in the wetter portion of the subzone; Pw is a suitable minor species 02 marginal sites for timber production; Fd is an alternative to Pl 03 Pl is an alternative to Fd on nutrient very poor to poor sites; Lw is a suitable minor species; Cw can function as a non-crop (nurse) species 04 Lw or Pw are suitable minor species 05 Pw is a suitable minor species 06 Fd is an alternative to Hw in the eastern variant (CWHm1); otherwise it is a suitable minor species, ecept on very moist / nutrient very poor to poor sites 07 Act or Dr are alternative management options ecept on soils with strong gleying in the upper 30 cm; Fd should be restricted to elevated microsites on strongly gleyed soils 11 marginal sites for timber production; elevated microsites are preferred 12 Pw and Ss are suitable minor species; elevated microsites are preferred 166

4 D Soil nutrient regime Very Very Poor Poor Medium Rich Rich A B C ~ E VD 0 MD 1 MD 2 SD 3 F 4 M 5 VM 6 Site W 7 series See comments on facing page * See grid # 23 for site series ** See grid # 32 for site series HwFd - Kindbergia 06 HwCw - Deer fern 02 FdPl - Cladina 07 Cw - Foamflower 03 FdHw - Salal 11 Pl - Sphagnum 04 Fd - Swordfern 12 CwSs - Skunk cabbage 05 Cw - Swordfern

5 Chapter 5.1 Bogs 53 TABLE Distribution of Bog Site Associations by biogeoclimatic zone BG BWBS SBPS PP SWB ESSF ICH IDF MS SBS CDF CWH MH Wb01 Black spruce Creeping-snowberry Peat-moss Wb02 Lodgepole pine Bog rosemary Peat-moss w Wb03 Black spruce Lingonberry Peat-moss Wb04 Western hemlock Cloudberry Peat-moss n Wb05 Black spruce Water sedge Peat-moss Wb06 Tamarack Water sedge Fen moss Wb07 Lodgepole pine Water sedge Peat-moss Wb08 Black spruce Soft-leaved sedge Peat-moss Wb09 Black spruce Common horsetail Peat-moss Wb10 Lodgepole pine Few-flowered sedge Peat-moss Wb11 Black spruce Buckbean Peat-moss w Wb12 Scheuchzeria Peat-moss Wb13 Shore sedge Buckbean Peat-moss Wb50 Labrador tea Bog-laurel Peat-moss s Wb51 Shore pine Crowberry Tough peat-moss Wb52 Common juniper Tufted clubrush Rock moss oc Wb53 Shore pine Yellow-cedar Tufted clubrush oc = incidental; < 5% of wetlands = minor; 5 25% of wetlands = major; >25% of wetlands w = wet/very wet subzones only n = northern subzones only oc = outer coast (hypermaritime) only s = southern subzones only

6 TABLE Bog Species Importance Table Species Wb01 Wb02 Wb03 Wb04 Wb05 Wb06 Wb07 Wb08 Trees Picea mariana yzzz yzz yzzzz y yzzz yzz yzzz Lari laricina yz yzzz Tsuga heterophylla y yzzz Pinus contorta var. latifolia yzz y y yzz Picea X yz y y yzz yz Thuja plicata Pinus contorta var. contorta Chamaecyparis nootkatensis Shrubs Ledum groenlandicum yzzzz yzzz yzzz yz yzz yzz yzz yzz Betula nana y yz y yzzz yzzz yzz yzz Sali myrtillifolia yz Lonicera involucrata y yz y Sali pedicellaris y yz y Myrica gale Vaccinium uliginosum Juniperus communis Herbs Oycoccus oycoccos yz yz y yz yz y yz y and Gaultheria hispidula yzz y y y Dwarf Vaccinium vitis-idaea yzz yz Shrubs Rubus chamaemorus yz yz yzzz y Care aquatilis/sitchensis y y y yzz yzzz yzzz yz Care disperma y yzzz Care tenuiflora yz Comarum palustre yz y y yzz Equisetum arvense y yz y yz yz Care pauciflora yz y Andromeda polifolia yz y Empetrum nigrum y yz y yz Care limosa y y Menyanthes trifoliata y Eriophorum angustifolium yz yz Kalmia microphylla yz yz Scheuchzeria palustris Drosera anglica Drosera rotundifolia y y Coptis trifolia y Care pluriflora Fauria crista-galli Care livida Sanguisorba officinalis Triantha glutinosa Trichophorum cespitosum Rhynchospora alba Agrostis aequivalvis Lichens Sphagnum Group I yzzzz yzzzz yzz yzzzz yzzz yzzz yzzzz yzz and Pleurozium schreberi yzz yz yzzz yzzz yz yz yz Mosses Hylocomium splendens y yzzz y yz Aulacomnium palustre yz y yz yzzz yzz yz Tomentypnum nitens y yzz yzzz yz yzz Sphagnum Group III y y Cladina spp. y yz y Cladonia spp. y y Sphagnum Group IV Racomitrium lanuginosum Siphula ceratites Campylopus atrovirens 54 Wetlands of British Columbia: A Field Guide to Identification

7 Wb09 Wb10 Wb11 Wb12 Wb13 Wb50 Wb51 Wb52 Wb53 Common Name yzzz y yzzz black spruce tamarack y y western hemlock yzz yz y lodgepole pine y y spruce yz y yz western redcedar y yzz yzz yzzz shore pine yz yz yzzzz yellow-cedar yzz yz yzz y yzzz yzz yz yzz Labrador tea yz yz yzz y scrub birch y bilberry willow y black twinberry y y yz bog willow yzz yz yzz sweet gale y yz y bog blueberry yz yzzz y common juniper y yz yzz yz y yzz y y bog cranberry y y creeping-snowberry y lingonberry y yzz cloudberry y yz yz y y y water sedge/sitka sedge y soft-leaved sedge y sparse-leaved sedge yz y y marsh cinquefoil yzzzz common horsetail yzzz y few-flowered sedge y yzz y yzz bog-rosemary y y y yzz yz yzz crowberry y yz yzz yzzz shore sedge yzzz y yzz buckbean yzz y y yzz yzz yzz yz narrow-leaved cotton-grass yzz y yz yz yzz yz yz yzz western bog-laurel yzzz scheuchzeria y yz y great sundew y yz y yzz yz round-leaved sundew y yz y three-leaved goldthread yz y many-flowered sedge yz yz deer-cabbage yz yz y pale sedge yzz yzzz yz great burnet y yz yz y sticky false-asphodel yz yzzzz yzzzz tufted clubrush y y yzz y white beak-rush yz y Alaska bentgrass yzzz yzzzz yzzz yzzz yzzzz yzzzz yzzzz yzz y peat-moss Group I yzz yz y y y yz red-stemmed feathermoss yzz step moss yzz y yz y y glow moss yz yz y golden fuzzy fen moss y y y y y yzzzz yzzz yzz peat-moss Group III y yzzz yz reindeer lichens yzz y clad lichens y yzz peat-moss Group IV yz yzzz yzz hoary rock-moss yzz northern waterfingers y bristly swan-neck moss Chapter 5.1 Bogs 55

8 Labrador tea Bog-laurel Peat-moss Wb50 Ledum groenlandicum Kalmia microphylla Sphagnum General Description Labrador tea Bog laurel Peat-moss bogs occur uncommonly in the drier subzones of the south Coast at low to montane elevations. They are raised bogs in closed basins with a high, stagnant watertable or adjacent to peatland lakes. Some locations may be on floating mats. The vegetation is low in stature and dominated by Ledum groenlandicum with an abundance of Kalmia microphylla and Oycoccus oycoccos. Myrica gale or dwarfed Pinus contorta var. contorta can be prominent on some, usually drier, sites. Herb cover is variable, low-lying areas can have a high cover of Rhynchospora alba while raised sites can have Rubus chamaemorus in abundance. Group I Sphagnum spp. are most common (S. fuscum, S. capillifolium) but coastal species also occur (S. papillosum), mostly in wetter hollows. Soils are Typic Fibrisols or Mesisols with surface tier of poorly decomposed Sphagnum peat. Characteristic Vegetation Tree layer ( ) Shrub layer ( ) Ledum groenlandicum, Myrica gale, Pinus contorta Herb layer ( ) Drosera rotundifolia, Kalmia microphylla, Oycoccus oycoccos, Rhynchospora alba Moss layer ( ) Sphagnum Group I Wetland Edatopic Grid Soil Nutrient Regime A B C D E F Comments The Wb50 is widespread but generally of small etent ecept for several notably etensive bogs in subdued terrain (e.g., Burns Bog). It occurs in open, unshaded locations adjacent to other low-stature peatland types or open water. The microtopography of this unit is often broken by peat degradation hollows caused by dieback of Sphagnum and increased localized decomposition. Shallow pools caused by peat degradation are frequent and are occupied by species such as Menyanthes trifoliata, Scheuchzeria palustris, or Nuphar lutea. Soil Moisture Regime VM W VA MA SA N Ak ph VW St Sl Mo Dy VD Hydrodynamic Inde Chapter 5.1 Bogs 69

9 Chapter 5.2 Fens 79 TABLE Distribution of Fen Site Associations by biogeoclimatic zone BG BWBS SBPS PP SWB ESSF ICH IDF MS SBS CDF CWH MH Wf01 Water sedge Beaked sedge i Wf02 Scrub birch Water sedge Wf03 Water sedge Peat-moss Wf04 Barclay s willow Water sedge Glow mosss Wf05 Slender sedge Common hook-moss Wf06 Slender sedge Buckbean Wf07 Scrub birch Buckbean Shore sedge Wf08 Shore sedge Buckbean Hook-moss Wf09 Few-flowered spike-rush Hook-moss Wf10 Hudson Bay clubrush Red hook-moss Wf11 Tufted clubrush Star moss Wf12 Narrow-leaved cotton-grass Marsh-marigold Wf13 Narrow-leaved cotton-grass Shore sedge Wf50 Narrow-leaved cotton-grass Peat-moss Wf51 Sitka sedge Peat-moss Wf52 Sweet gale Sitka sedge s Wf53 Slender sedge White beak-rush s = incidental; < 5% of wetlands = minor; 5 25% of wetlands = major; >25% of wetlands i = inland areas only s = southern subzones only

10 TABLE Fen Species Importance Table Species Wf01 Wf02 Wf03 Wf04 Wf05 Wf06 Wf07 Wf08 Shrubs Betula nana yzzz y yzzz Sali barclayi yzzzz Sali pedicellaris yz y y yzz y Spiraea douglasii Myrica gale Herbs Care utriculata yzzz yz y y yz and Care aquatilis yzzz yzz yzzz yzz yz yz Dwarf Comarum palustre y yz y y y yzz y Shrubs Calamagrostis canadensis y yzz Care lasiocarpa yzzzz yzzzz y Menyanthes trifoliata yzzz yzzz yzz Care limosa y yzz yzzz Care chordorrhiza y yz y Eleocharis quinqueflora Trichophorum alpinum Trichophorum cespitosum Eriophorum angustifolium y y y y Caltha leptosepala y y Care anthoanthea Equisetum fluviatile y y y y Care magellanica Care sitchensis y y yz yz Rhynchospora alba Care livida Eriophorum chamissonis Vahlodea atropurpurea Drosera anglica y Hypericum anagalloides Triantha glutinosa y Schoenoplectus tabernaemontani Fauria crista-galli Senecio triangularis yz y Andromeda polifolia y y Kalmia microphylla Oycoccus oycoccos y Triglochin maritima y y Drosera rotundifolia Leptarrhena pyrolifolia y Platanthera dilatata y Sanguisorba canadensis y Utricularia intermedia y Viola palustris Lichens Sphagnum Group I y yz yzz yz and Aulacomnium palustre yz yz yzz Mosses Drepanocladus spp. yz y yzz yz yz yz Sphagnum Group II yz yz y Tomentypnum nitens yzz yz y yz y Philonotis fontana y yz Calliergon stramineum Scorpidium spp. y yzz y Campylium stellatum y y Warnstorfia spp. y yz y Meesia triquetra y y 80 Wetlands of British Columbia: A Field Guide to Identification

11 Wf09 Wf10 Wf11 Wf12 Wf13 Wf50 Wf51 Wf52 Wf53 Common Name y scrub birch Barclay s willow y bog willow yz pink spirea yzzzz yz sweet gale y y beaked sedge yz y yz water sedge y yz y marsh cinquefoil y y y y bluejoint reedgrass yz y yzzz slender sedge yzzz yz y buckbean yz yzz yz yzz shore sedge yzz cordroot sedge yzzzz few-flowered spike-rush yzzzz Hudson Bay clubrush yzzzz yz tufted clubrush yz yz yzzzz yzzz yzzzz y narrow-leaved cotton-grass y yzz yz white mtn. marsh-marigold y yellow-flowered sedge swamp horsetail yz poor sedge y yzzzz yzzz Sitka sedge y yzz white beak-rush y pale sedge y Chamisso s cotton-grass y y mountain hairgrass yzz y y great sundew bog St. John s-wort yz y y y sticky asphodel y great bulrush yz deer-cabbage arrow-leaved groundsel yz bog-rosemary y yz western bog-laurel yz y bog cranberry yz seaside arrow-grass y y round-leaved sundew y y leatherleaf saifrage y y fragrant white rein orchid y y Sitka burnet y flat-leaved bladderwort y marsh violet y y yz yzz yzz peat-moss Group I y yz yz y y glow moss yz y y hook-mosses y yz yz yzz peat-moss Group II yz yz y golden fuzzy fen moss y yz spring moss y yz y straw spear-moss y yzz sausage-moss yzzz yzzz y yellow star-moss y y hook-mosses y three-ranked hump-moss Chapter 5.2 Fens 81

12 Hudson Bay clubrush Red hook-moss Wf10 Trichophorum alpinum Scorpidium revolvens General Description The Hudson Bay clubrush Red hook-moss Site Association is rare and seems to occur only in the moist subzones of the SBS. It is floristically related to the Wf11 but occurs where the watertable is more stagnant and at or slightly above the peat surface for much of the growing season. Common locations are around small peatland lakes and ponds, and in flarks. Trichophorum alpinum dominates but there is usually a diverse array of other species typical of base-rich and saturated peatland habitats such as Care chordorrhiza, C. lasiocarpa, C. limosa, Menyanthes trifoliata, and Triglochin maritima. The moss flora is dominated by brown mosses and strong calciphiles: Campylium stellatum, Scorpidium revolvens, and S. scorpioides. Many sites are underlain by calcareous marl, and peat water is usually neutral to alkaline. Peat decomposition is apparently retarded under these conditions because the entire peat profile often has few signs of decomposition. Typic Fibrisols are common. Peat is usually deep (> 3 m). Characteristic Vegetation Tree layer ( ) Shrub layer ( ) Herb layer ( ) Andromeda polifolia, Care aquatilis, C. chordorrhiza, C. lasiocarpa, C. limosa, Drosera anglica, Menyanthes trifoliata, Oycoccus oycoccos,triantha glutinosa, Trichophorum alpinum,triglochin maritima Moss layer ( ) Calliergon stramineum, Campylium stellatum, Scorpidium revolvens, S. scorpioides, Sphagnum Group II,Tomentypnum nitens Comments Wetland Edatopic Grid Soil Nutrient Regime A B C D E F Wf10 sites are usually small inclusions in larger complees of rich fen peatland but are conspicuous when Trichophorum alpinum is in flower. Most site conditions are similar to the Wf 08 but the Wf10 occurs where soil water is alkaline and (apparently) occurs over a much more restricted climatic range. Soil Moisture Regime VM W VA MA SA N Ak ph VW St Sl Mo Dy VD Hydrodynamic Inde Chapter 5.2 Fens 91

13 Chapter 5.2 Fens 79 TABLE Distribution of Fen Site Associations by biogeoclimatic zone BG BWBS SBPS PP SWB ESSF ICH IDF MS SBS CDF CWH MH Wf01 Water sedge Beaked sedge i Wf02 Scrub birch Water sedge Wf03 Water sedge Peat-moss Wf04 Barclay s willow Water sedge Glow mosss Wf05 Slender sedge Common hook-moss Wf06 Slender sedge Buckbean Wf07 Scrub birch Buckbean Shore sedge Wf08 Shore sedge Buckbean Hook-moss Wf09 Few-flowered spike-rush Hook-moss Wf10 Hudson Bay clubrush Red hook-moss Wf11 Tufted clubrush Star moss Wf12 Narrow-leaved cotton-grass Marsh-marigold Wf13 Narrow-leaved cotton-grass Shore sedge Wf50 Narrow-leaved cotton-grass Peat-moss Wf51 Sitka sedge Peat-moss Wf52 Sweet gale Sitka sedge s Wf53 Slender sedge White beak-rush s = incidental; < 5% of wetlands = minor; 5 25% of wetlands = major; >25% of wetlands i = inland areas only s = southern subzones only

14 TABLE Fen Species Importance Table Species Wf01 Wf02 Wf03 Wf04 Wf05 Wf06 Wf07 Wf08 Shrubs Betula nana yzzz y yzzz Sali barclayi yzzzz Sali pedicellaris yz y y yzz y Spiraea douglasii Myrica gale Herbs Care utriculata yzzz yz y y yz and Care aquatilis yzzz yzz yzzz yzz yz yz Dwarf Comarum palustre y yz y y y yzz y Shrubs Calamagrostis canadensis y yzz Care lasiocarpa yzzzz yzzzz y Menyanthes trifoliata yzzz yzzz yzz Care limosa y yzz yzzz Care chordorrhiza y yz y Eleocharis quinqueflora Trichophorum alpinum Trichophorum cespitosum Eriophorum angustifolium y y y y Caltha leptosepala y y Care anthoanthea Equisetum fluviatile y y y y Care magellanica Care sitchensis y y yz yz Rhynchospora alba Care livida Eriophorum chamissonis Vahlodea atropurpurea Drosera anglica y Hypericum anagalloides Triantha glutinosa y Schoenoplectus tabernaemontani Fauria crista-galli Senecio triangularis yz y Andromeda polifolia y y Kalmia microphylla Oycoccus oycoccos y Triglochin maritima y y Drosera rotundifolia Leptarrhena pyrolifolia y Platanthera dilatata y Sanguisorba canadensis y Utricularia intermedia y Viola palustris Lichens Sphagnum Group I y yz yzz yz and Aulacomnium palustre yz yz yzz Mosses Drepanocladus spp. yz y yzz yz yz yz Sphagnum Group II yz yz y Tomentypnum nitens yzz yz y yz y Philonotis fontana y yz Calliergon stramineum Scorpidium spp. y yzz y Campylium stellatum y y Warnstorfia spp. y yz y Meesia triquetra y y 80 Wetlands of British Columbia: A Field Guide to Identification

15 Wf09 Wf10 Wf11 Wf12 Wf13 Wf50 Wf51 Wf52 Wf53 Common Name y scrub birch Barclay s willow y bog willow yz pink spirea yzzzz yz sweet gale y y beaked sedge yz y yz water sedge y yz y marsh cinquefoil y y y y bluejoint reedgrass yz y yzzz slender sedge yzzz yz y buckbean yz yzz yz yzz shore sedge yzz cordroot sedge yzzzz few-flowered spike-rush yzzzz Hudson Bay clubrush yzzzz yz tufted clubrush yz yz yzzzz yzzz yzzzz y narrow-leaved cotton-grass y yzz yz white mtn. marsh-marigold y yellow-flowered sedge swamp horsetail yz poor sedge y yzzzz yzzz Sitka sedge y yzz white beak-rush y pale sedge y Chamisso s cotton-grass y y mountain hairgrass yzz y y great sundew bog St. John s-wort yz y y y sticky asphodel y great bulrush yz deer-cabbage arrow-leaved groundsel yz bog-rosemary y yz western bog-laurel yz y bog cranberry yz seaside arrow-grass y y round-leaved sundew y y leatherleaf saifrage y y fragrant white rein orchid y y Sitka burnet y flat-leaved bladderwort y marsh violet y y yz yzz yzz peat-moss Group I y yz yz y y glow moss yz y y hook-mosses y yz yz yzz peat-moss Group II yz yz y golden fuzzy fen moss y yz spring moss y yz y straw spear-moss y yzz sausage-moss yzzz yzzz y yellow star-moss y y hook-mosses y three-ranked hump-moss Chapter 5.2 Fens 81

16 Sweet gale Sitka sedge Wf52 Myrica gale Care sitchensis General Description Sweet gale Sitka sedge fens are uncommon at low elevations in the Georgia Depression and Coast and Mountains in a wide variety of landscape positions. Sites can be shallowly flooded in the early season but will drop just below the surface for most of the growing season. Myrica gale and Spiraea douglasii form a closed and sometimes dense thicket mostly < 1.5 m in height. Care sitchensis dominates the herb layer but there is a scattering of other species on most sites. Because of flooding, the bryophyte layer is generally sparse but on some sites cover of Sphagnum or other moss species may be high. Peat deposits are mostly shallow, moderately to well decomposed sedge and wood peat. Terric Humisols and Mesisols are common soil types. Characteristic Vegetation Tree layer ( ) Shrub layer ( ) Myrica gale, Spiraea douglasii Herb layer ( ) Care sitchensis Moss layer ( ) Sphagnum spp. Comments The Wf52 Site Association is common as a component of many peatlands in the south Coast. It is most often found in comple with the Wm50 in more peripheral (and drier) locations but occurs around other Site Associations as well, including estuarine marshes. Shrub thickets dominated by Spiraea douglasii with sparse Myrica gale and Care spp. are common in the region where the Wf52 occurs.these communities are usually on mineral soil and described by the Ws50 Site Association. Soil Moisture Regime VM W VW Wetland Edatopic Grid Soil Nutrient Regime A B C D E F VA MA SA N Ak ph St Sl Mo Dy VD Hydrodynamic Inde Chapter 5.2 Fens 97

17 Chapter 5.2 Fens 79 TABLE Distribution of Fen Site Associations by biogeoclimatic zone BG BWBS SBPS PP SWB ESSF ICH IDF MS SBS CDF CWH MH Wf01 Water sedge Beaked sedge i Wf02 Scrub birch Water sedge Wf03 Water sedge Peat-moss Wf04 Barclay s willow Water sedge Glow mosss Wf05 Slender sedge Common hook-moss Wf06 Slender sedge Buckbean Wf07 Scrub birch Buckbean Shore sedge Wf08 Shore sedge Buckbean Hook-moss Wf09 Few-flowered spike-rush Hook-moss Wf10 Hudson Bay clubrush Red hook-moss Wf11 Tufted clubrush Star moss Wf12 Narrow-leaved cotton-grass Marsh-marigold Wf13 Narrow-leaved cotton-grass Shore sedge Wf50 Narrow-leaved cotton-grass Peat-moss Wf51 Sitka sedge Peat-moss Wf52 Sweet gale Sitka sedge s Wf53 Slender sedge White beak-rush s = incidental; < 5% of wetlands = minor; 5 25% of wetlands = major; >25% of wetlands i = inland areas only s = southern subzones only

18 TABLE Fen Species Importance Table Species Wf01 Wf02 Wf03 Wf04 Wf05 Wf06 Wf07 Wf08 Shrubs Betula nana yzzz y yzzz Sali barclayi yzzzz Sali pedicellaris yz y y yzz y Spiraea douglasii Myrica gale Herbs Care utriculata yzzz yz y y yz and Care aquatilis yzzz yzz yzzz yzz yz yz Dwarf Comarum palustre y yz y y y yzz y Shrubs Calamagrostis canadensis y yzz Care lasiocarpa yzzzz yzzzz y Menyanthes trifoliata yzzz yzzz yzz Care limosa y yzz yzzz Care chordorrhiza y yz y Eleocharis quinqueflora Trichophorum alpinum Trichophorum cespitosum Eriophorum angustifolium y y y y Caltha leptosepala y y Care anthoanthea Equisetum fluviatile y y y y Care magellanica Care sitchensis y y yz yz Rhynchospora alba Care livida Eriophorum chamissonis Vahlodea atropurpurea Drosera anglica y Hypericum anagalloides Triantha glutinosa y Schoenoplectus tabernaemontani Fauria crista-galli Senecio triangularis yz y Andromeda polifolia y y Kalmia microphylla Oycoccus oycoccos y Triglochin maritima y y Drosera rotundifolia Leptarrhena pyrolifolia y Platanthera dilatata y Sanguisorba canadensis y Utricularia intermedia y Viola palustris Lichens Sphagnum Group I y yz yzz yz and Aulacomnium palustre yz yz yzz Mosses Drepanocladus spp. yz y yzz yz yz yz Sphagnum Group II yz yz y Tomentypnum nitens yzz yz y yz y Philonotis fontana y yz Calliergon stramineum Scorpidium spp. y yzz y Campylium stellatum y y Warnstorfia spp. y yz y Meesia triquetra y y 80 Wetlands of British Columbia: A Field Guide to Identification

19 Wf09 Wf10 Wf11 Wf12 Wf13 Wf50 Wf51 Wf52 Wf53 Common Name y scrub birch Barclay s willow y bog willow yz pink spirea yzzzz yz sweet gale y y beaked sedge yz y yz water sedge y yz y marsh cinquefoil y y y y bluejoint reedgrass yz y yzzz slender sedge yzzz yz y buckbean yz yzz yz yzz shore sedge yzz cordroot sedge yzzzz few-flowered spike-rush yzzzz Hudson Bay clubrush yzzzz yz tufted clubrush yz yz yzzzz yzzz yzzzz y narrow-leaved cotton-grass y yzz yz white mtn. marsh-marigold y yellow-flowered sedge swamp horsetail yz poor sedge y yzzzz yzzz Sitka sedge y yzz white beak-rush y pale sedge y Chamisso s cotton-grass y y mountain hairgrass yzz y y great sundew bog St. John s-wort yz y y y sticky asphodel y great bulrush yz deer-cabbage arrow-leaved groundsel yz bog-rosemary y yz western bog-laurel yz y bog cranberry yz seaside arrow-grass y y round-leaved sundew y y leatherleaf saifrage y y fragrant white rein orchid y y Sitka burnet y flat-leaved bladderwort y marsh violet y y yz yzz yzz peat-moss Group I y yz yz y y glow moss yz y y hook-mosses y yz yz yzz peat-moss Group II yz yz y golden fuzzy fen moss y yz spring moss y yz y straw spear-moss y yzz sausage-moss yzzz yzzz y yellow star-moss y y hook-mosses y three-ranked hump-moss Chapter 5.2 Fens 81

20 Wf53 Slender sedge White beak-rush Care lasiocarpa Rhynchospora alba General Description Slender sedge White beak-rush fens occur in the Georgia Depression at elevations below 600 m. The Wf 53 requires permanently saturated soils and is tolerant of prolonged shallow inundation. Lake margins are the most common location but some isolated basins may also have suitable conditions. Care lasiocarpa is always abundant and dominant. Rhynchospora alba and scattered low-growing Myrica gale occur on most sites. However, wetter sites often lack these species and have aquatic species such as Nuphar lutea, Brasenia schreberi, or Menyanthes trifoliata instead. Schoenoplectus acutus grows in more alkaline eamples of the Wf 53. Soils are shallow mesic or humic peat of sedge or limnic origin. Terric Mesisols and Humisols are common soil types. Characteristic Vegetation Tree layer ( ) Shrub layer ( ) Myrica gale Herb layer ( ) Care lasiocarpa, Rhynchospora alba Moss layer ( ) Comments Wetland Edatopic Grid Soil Nutrient Regime A B C D E F Coastal Care lasiocarpa stands occur on a range of ecological conditions from semi-terrestrial to shallowly flooded and marsh-like peatlands. Ceska (1978) observed variants of this unit: a typic with Rhynchospora alba,a limose variant with Nuphar lutea, a mineric variant with Dulichium arundinaceum and Schoenoplectus acutus, and a higherelevation variant with Care limosa. With sufficient additional data, several more specific classification units based on the presence of additional dominants might be indicated. Care lasiocarpa communities with abundant Spiraea douglasii and Myrica gale occur on drier and hummocky sites (see additional units). The Wf52 is similar but grows on drier and more acidic sites than the Wf53.The Wf53 is analogous to the Wf 05 of the Interior but has little or no moss cover and includes coastal species. Soil Moisture Regime VM W VA MA SA N Ak ph VW St Sl Mo Dy VD Hydrodynamic Inde 98 Wetlands of British Columbia: A Field Guide to Identification

21 Chapter 5.3 Marshes 105 TABLE Distribution of Marsh Site Associations by biogeoclimatic zone BG BWBS SBPS PP SWB ESSF ICH IDF MS SBS CDF CWH MH Wm01 Beaked sedge Water sedge Wm02 Swamp horsetail Beaked sedge Wm03 Awned sedge Wm04 Common spike-rush Wm05 Cattail s Wm06 Great bulrush Wm07 Baltic rush Wm50 Sitka sedge Hemlock-parsley Wm51 Three-way sedge = incidental; < 5% of wetlands = minor; 5 25% of wetlands = major; >25% of wetlands s = southern subzones only

22 TABLE Marsh Species Importance Table Species Wm01 Wm02 Wm03 Wm04 Wm05 Herbs Care utriculata yzzz yzzz y and Care aquatilis yzz y Dwarf Equisetum fluviatile yzzzz Shrubs Comarum palustre y y Sium suave y Care esiccata Care atherodes yzzzz Polygonum amphibium y Eleocharis palustris yzzzz Potamogeton richardsonii yz Typha latifolia yzzzz Schoenoplectus acutus Menyanthes trifoliata Utricularia macrorhiza Juncus balticus Hordeum jubatum Potentilla anserina Calamagrostis canadensis y y Cicuta douglasii Lysichiton americanus Oenanthe sarmentosa Galium trifidum Spiraea douglasii Care sitchensis Nuphar lutea ssp. polysepala Dulichium arundinaceum Mosses Drepanocladus spp. y y y Warnstorfia spp. 106 Wetlands of British Columbia: A Field Guide to Identification

23 Wm05 Cattail Typha latifolia General Description Cattail marshes are common throughout the Coast and Interior at low elevations in subzones with warm summers. They occur most commonly in protected lake embayments and potholes or even roadside ditches, where the surface substrate remains saturated for most of the growing season. Typha latifolia dominates, often with few other rooted plants present, especially where nutrient levels are high and T. latifolia growth profuse. Occasionally there is significant cover of Care utriculata, Schoenoplectus acutus, or Lemna spp. These sites often have organic veneers of well-decomposed, odiferous muck. Soil types can be Humisols or Humic Gleysols. Water depths may be up to 1 m in the spring but recede in late summer, sometimes to the surface. Characteristic Vegetation Tree layer ( ) Shrub layer ( ) Herb layer ( ) Typha latifolia Moss layer ( ) Comments Typha latifolia effectively turns high nutrient levels (N and P) into biomass and often dominates wetlands eperiencing nutrient loading. Addition of agricultural or human waste to most wetlands will lead to an increase and eventual dominance by T. latifolia if climatic conditions are favourable. Initial T. latifolia establishment requires substrate Wetland Edatopic Grid Soil Nutrient Regime A B C D E F eposure for seedling establishment and germination, though once established it spreads etensively by rhizomes so that large stands may consist of only a few individual plants. Similar sites with more dynamic hydrology or lower N and P are usually occupied by Wm06. Patches of S. acutus in Wm05 marshes can be a result of intensive grazing by Muskrat. S. acutus stores nutrients in the root mass and can more rapidly recover from removal of its stem than can T. latifolia. Soil Moisture Regime VM W VA MA SA N Ak ph VW St Sl Mo Dy VD Hydrodynamic Inde 112 Wetlands of British Columbia: A Field Guide to Identification

24 Chapter 5.3 Marshes 105 TABLE Distribution of Marsh Site Associations by biogeoclimatic zone BG BWBS SBPS PP SWB ESSF ICH IDF MS SBS CDF CWH MH Wm01 Beaked sedge Water sedge Wm02 Swamp horsetail Beaked sedge Wm03 Awned sedge Wm04 Common spike-rush Wm05 Cattail s Wm06 Great bulrush Wm07 Baltic rush Wm50 Sitka sedge Hemlock-parsley Wm51 Three-way sedge = incidental; < 5% of wetlands = minor; 5 25% of wetlands = major; >25% of wetlands s = southern subzones only

25 TABLE Marsh Species Importance Table Species Wm01 Wm02 Wm03 Wm04 Wm05 Herbs Care utriculata yzzz yzzz y and Care aquatilis yzz y Dwarf Equisetum fluviatile yzzzz Shrubs Comarum palustre y y Sium suave y Care esiccata Care atherodes yzzzz Polygonum amphibium y Eleocharis palustris yzzzz Potamogeton richardsonii yz Typha latifolia yzzzz Schoenoplectus acutus Menyanthes trifoliata Utricularia macrorhiza Juncus balticus Hordeum jubatum Potentilla anserina Calamagrostis canadensis y y Cicuta douglasii Lysichiton americanus Oenanthe sarmentosa Galium trifidum Spiraea douglasii Care sitchensis Nuphar lutea ssp. polysepala Dulichium arundinaceum Mosses Drepanocladus spp. y y y Warnstorfia spp. 106 Wetlands of British Columbia: A Field Guide to Identification

26 Wm06 Wm07 Wm50 Wm51 Common Name beaked sedge water sedge swamp horsetail y y marsh cinquefoil hemlock water-parsnip y inflated sedge awned sedge water smartweed common spike-rush Richardson s pondweed common cattail yzzzz great bulrush y buckbean greater bladderwort yzzzz Baltic rush yz fotail barley yz common silverweed bluejoint Douglas water-hemlock y skunk cabbage yzz Pacific water-parsley yz small bedstraw y pink spirea yzzzz yz Sitka sedge yz yellow pond-lily yzzzz three-way sedge hook-mosses: intermediate hook-mosses: poor Chapter 5.3 Marshes 107

27 Great bulrush Wm06 Schoenoplectus acutus General Description Great bulrush marshes occur widely in subzones with warm and dry summers. Wave-eposed lake embayments with significant water movements, and grassland potholes with occasional substrate eposure (conditions that provide abundant aeration and limit organic accumulations), are the most common locations for this Site Association. Plant diversity is low; typically, Schoenoplectus acutus is the only species with significant cover. Bulrush marshes are usually adjacent to open water in wetland mosaics and can sometimes be found in comple with the Wm05. Floodwaters to 1.5 m depth in the spring are typical, with significant growing-season drawdown occurring in potholes. Great bulrush is tolerant of alkali soils and often dominates in brackish potholes. Soils are mostly Gleysols and Humic Gleysols, though Terric Humisols occasionally occur. Characteristic Vegetation Tree layer ( ) Shrub layer ( ) Herb layer ( ) Schoenoplectus acutus Moss layer ( ) Comments The Wm06 includes marshes dominated by S. tabernaemontani (soft-stemmed bulrush). On wave-eposed lake shorelines or where sites are more brackish, S. acutus is more frequent, while in protected waters and potholes with mucky substrates, S. tabernaemontani is typical. Wetland Edatopic Grid Soil Nutrient Regime A B C D E F Site conditions for Wm05 and Wm06 overlap. S. acutus dominates on sites with alkaline mineral soils, greater wave eposure, or pronounced surface drying. Where marshes are heavily grazed by Muskrat, S. acutus is often favoured over Typha latifolia because it stores nutrients in the root mass and recovers more rapidly from grazing. Soil Moisture Regime VM W VA MA SA N Ak ph VW St Sl Mo Dy VD Hydrodynamic Inde Chapter 5.3 Marshes 113

28 Chapter 5.3 Marshes 105 TABLE Distribution of Marsh Site Associations by biogeoclimatic zone BG BWBS SBPS PP SWB ESSF ICH IDF MS SBS CDF CWH MH Wm01 Beaked sedge Water sedge Wm02 Swamp horsetail Beaked sedge Wm03 Awned sedge Wm04 Common spike-rush Wm05 Cattail s Wm06 Great bulrush Wm07 Baltic rush Wm50 Sitka sedge Hemlock-parsley Wm51 Three-way sedge = incidental; < 5% of wetlands = minor; 5 25% of wetlands = major; >25% of wetlands s = southern subzones only

29 TABLE Marsh Species Importance Table Species Wm01 Wm02 Wm03 Wm04 Wm05 Herbs Care utriculata yzzz yzzz y and Care aquatilis yzz y Dwarf Equisetum fluviatile yzzzz Shrubs Comarum palustre y y Sium suave y Care esiccata Care atherodes yzzzz Polygonum amphibium y Eleocharis palustris yzzzz Potamogeton richardsonii yz Typha latifolia yzzzz Schoenoplectus acutus Menyanthes trifoliata Utricularia macrorhiza Juncus balticus Hordeum jubatum Potentilla anserina Calamagrostis canadensis y y Cicuta douglasii Lysichiton americanus Oenanthe sarmentosa Galium trifidum Spiraea douglasii Care sitchensis Nuphar lutea ssp. polysepala Dulichium arundinaceum Mosses Drepanocladus spp. y y y Warnstorfia spp. 106 Wetlands of British Columbia: A Field Guide to Identification

30 Wm06 Wm07 Wm50 Wm51 Common Name beaked sedge water sedge swamp horsetail y y marsh cinquefoil hemlock water-parsnip y inflated sedge awned sedge water smartweed common spike-rush Richardson s pondweed common cattail yzzzz great bulrush y buckbean greater bladderwort yzzzz Baltic rush yz fotail barley yz common silverweed bluejoint Douglas water-hemlock y skunk cabbage yzz Pacific water-parsley yz small bedstraw y pink spirea yzzzz yz Sitka sedge yz yellow pond-lily yzzzz three-way sedge hook-mosses: intermediate hook-mosses: poor Chapter 5.3 Marshes 107

31 Sitka sedge Hemlock-parsley Wm50 Care sitchensis Oenanthe sarmentosa General Description Sitka sedge Hemlock-parsley marshes are common in the Georgia Depression and Coast and Mountains at low elevations in basins, and along slow-moving streams, ponds, and lakeshores. A monoculture of Care sitchensis occurs on many sites, but occasionally other species are also prominent. Sites with flowing floodwaters often have abundant Oenanthe sarmentosa or Glyceria elata. Drier sites have a mi of forbs such as Veronica scutellata, Hypericum anagalloides, and Galium trifidum. The Wm50 tolerates variable hydrology and disturbance and occurs on mineral substrates or shallow (occasionally deep) peat veneers. Characteristic Vegetation Tree layer ( ) Shrub layer ( ) Herb layer ( ) Care sitchensis, Galium trifidum, Oenanthe sarmentosa Moss layer ( ) Comments The Wm50 is the coastal equivalent of the Wm01 of the Interior. Ceska (1978) describes several variants of the Wm50, including Care sitchensis with C. obnupta, Cicuta douglasii, and Aster subspicatus occurring adjacent to alder forests, with Deschampsia cespitosa, Gentiana sceptrum, and Hypericum anagalloides on drier sites, or with Glyceria elata and Calamagrostis canadensis in shaded areas with waterflow. Soil Moisture Regime VM W VW Wetland Edatopic Grid Soil Nutrient Regime A B C D E F VA MA SA N Ak ph St Sl Mo Dy VD Hydrodynamic Inde Chapter 5.3 Marshes 115

32 Chapter 5.4 Swamps 125 TABLE Distribution of Swamp Site Associations by biogeoclimatic zone BG BWBS SBPS PP SWB ESSF ICH IDF MS SBS CDF CWH MH Ws01 Mountain alder Skunk cabbage Lady fern w Ws02 Mountain alder Pink spirea Sitka sedge w Ws03 Bebb s willow Bluejoint Ws04 Drummond s willow Beaked sedge Ws05 MacCalla s willow Beaked sedge Ws06 Sitka willow Sitka sedge w Ws07 Spruce Common horsetail Leafy moss Ws08 Subalpine fir Sitka valerian Common horsetail Ws09 Black spruce Skunk cabbage Peat-moss w Ws10 Western redcedar Spruce Skunk cabbage Ws11 Spruce Subalpine fir Skunk cabbage w Ws50 Pink spirea Sitka sedge w Ws51 Sitka willow Pacific willow Skunk cabbage Ws52 Red alder Skunk cabbage Ws53 Western redcedar Sword fern Skunk cabbage Ws54 Western redcedar Western hemlock Skunk cabbage Ws55 Yellow-cedar Mountain hemlock Skunk cabbage = incidental; < 5% of wetlands = minor; 5 25% of wetlands = major; >25% of wetlands w = wet subzones only = very dry subzones only

33 TABLE Swamp Species Importance Table Species Ws03 Ws04 Ws05 Ws02 Ws06 Ws07 Ws08 Ws01 Trees Picea X yzzz yzzz yz Picea mariana Abies lasiocarpa y yzzzz y Tsuga heterophylla Thuja plicata Picea sitchensis Alnus rubra Acer macrophyllum Chamaecyparis nootkatensis Tsuga mertensiana Abies amabilis Shrubs Sali bebbiana yzzzz Sali drummondiana yzzz Sali maccalliana yzzzz Alnus incana yzz yzzz yz yz yzzzz Lonicera involucrata yz y y y y yzz y yz Spiraea douglasii y yzz y yzz Cornus stolonifera yz y y y Vaccinium alaskaense/ovalifolium y Sali sitchensis y yzzzz Sali lucida Rubus spectabilis Sambucus racemosa Gaultheria shallon Ribes bracteosum Elliottia pyroliflorus Herbs Calamagrostis canadensis yzzz yz yzz yzz yz y y yz and Care aquatilis/sitchensis yzz yzz yzzzz yzzz y Dwarf Care utriculata yz yzz yzzz y yz Shrubs Gymnocarpium dryopteris y y y Valeriana sitchensis yzz Scirpus microcarpus yz Equisetum arvense yzz y yzz yzzzz yzzz yz Lysichiton americanus y yzzzz Athyrium fili-femina y yzzz Tiarella trifoliata y y Streptopus lanceolatus Maianthemum dilatatum Oenanthe sarmentosa Polystichum munitum Equisetum telmateia Blechnum spicant Veratrum viride y Fauria crista-galli Mosses Drepanocladus spp. yzz and Mnium spp. yz y yz yz y yzzz yzzz yzz Lichens Aulacomnium palustre y yz yzz yzz Sphagnum spp. Hylocomium splendens yzz Pleurozium schreberi yz y Eurhynchium praelongum Rhytidiadelphus loreus 126 Wetlands of British Columbia: A Field Guide to Identification

34 Ws09 Ws10 Ws11 Ws50 Ws51 Ws52 Ws53 Ws54 Ws55 Common Name yz yzz yzz spruce yzz black spruce yzzz yzz yzzzz subalpine fir y yzzz yzz yzzzz yzzzz western hemlock yzzzz yz yzzzz yzzz y western redcedar y yz yzz Sitka spruce y yzzzz yzzz y red alder yz yzz bigleaf maple y yzzzz yellow-cedar yzzzz mountain hemlock yz yzzz amabilis fir Bebb s willow Drummond s willow MacCalla s willow yzz y yzzz mountain alder y y yzz yz black twinberry yzz yz yzzzz yz pink spirea y y yz y y red-osier dogwood yz yzz yz yzzz yzzzz Alaska/oval-leaved blueberry yzzzz Sitka willow yzzzz Pacific willow yzz yzzzz yzzz yzz yz salmonberry yzzz yzz red elderberry y yzz salal yzz y stink currant yz copperbush yz y y bluejoint yzz water/sitka sedge y beaked sedge y yzz yzz y y oak fern Sitka valerian yz small-flowered bulrush yzz yzz yzz yz common horsetail yzzzz yzzz yzzzz y yzzzz yzzzz yzzz yzzz yzzz skunk cabbage yz yzzz yzzz yzz yzzz yzzz yzz yz lady fern yz yzz yz yz yz y foamflower y yz yz y y rosy twistedstalk yzz yzz y y false lily-of-the-valley yzz y Pacific water-parsley yz yzz sword fern y yzz giant horsetail yzz yz deer fern yz Indian hellebore yz deer-cabbage hook-mosses yz yzzz yzzz yz yzz yzz yzz yzz leafy mosses y y glow moss yzzz yzz yz y yz yzz peat-mosses yz yzz yz step moss yzz yz y red-stemmed feather-moss y yzzz yzzz y beak moss yzz yzz lanky moss Chapter 5.4 Swamps 127

35 Pink spirea Sitka sedge Ws50 Spiraea douglasii Care sitchensis General Description Pink spirea Sitka sedge swamps are common at low elevations of the Georgia Depression in basins, gullies, and margins of waterbodies and peatlands. These sites eperience prolonged saturation and brief early-season flooding. Species diversity is low in this Site Association. Spiraea douglasii always dominates Ws50 sites; few other shrub species occur. The sedge-dominated understorey is sparse or well developed. Few species other than Care sitchensis are common. The moss layer is often minimal but Aulacomnium palustre or Sphagnum spp. occur with high abundance on some sites. Humisols and Gleysols are the most common soil types. Characteristic Vegetation Tree layer ( ) Shrub layer ( ) Spiraea douglasii Herb layer ( ) Care sitchensis Moss layer ( ) Aulacomnium palustre, Sphagnum Group I Comments The Ws50 Site Association is common as a component of many peatlands along the southern Coast. It can be the dominant Site Association in small basins or surrounding Wm50 marshes. S. douglasii increases with disturbance and many spirea thickets actually represent disturbance communities that have developed after hydrological change. Understoreys in these successional communities vary from completely absent to bog-like. Shrub thickets dominated by Myrica gale with sedge are common in the region where the Ws50 occurs.these communities are usually on peat and are described by the Wf52 Site Association. Soil Moisture Regime VM W VW Wetland Edatopic Grid Soil Nutrient Regime A B C D E F VA MA SA N Ak ph St Sl Mo Dy VD Hydrodynamic Inde Chapter 5.4 Swamps 139