Alpine and High Subalpine Plant Communities of the North Cascades Range, Washington and British Columbia Author(S): George W

Alpine and High Subalpine Plant Communities of the North Cascades Range, Washington and British Columbia Author(s): George W. Douglas and L. C. Bliss Source: Ecological Monographs, Vol. 47, No. 2 (Spring, 1977), pp. 113-150 Published by: Ecological Society of America Stable URL: http://www.jstor.org/stable/1942614 . Accessed: 27/08/2013 19:27

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This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Ecological Monographs (1977) 47: pp. 113-150

ALPINE AND HIGH SUBALPINE PLANT COMMUNITIES OF THE NORTH CASCADES RANGE, WASHINGTON AND BRITISH COLUMBIA'

GEORGE W. DOUGLAS2 AND

L. C. BLISS Department of Botany, Universityof Alberta, Edmonton, Alberta, Canada

A bstract. Communitytypes were describedfrom 209 stands in the alpine zone of the NorthCascades Range. The maritimeto continentalclimatic change from west to east has a profoundeffect on regionalvegetation patterns. Most of the communitytypes in the eastern NorthCascades are closelyrelated to those in the Rocky Mountains,southern Alaska and the southernYukon whereascommunities in the westernNorth Cascades are more similarto communitiesin otherwest coast ranges. Soils in the region include Entisols,Inceptisols, and Spodosols. Physical propertiesare quite similarin mostsoils. Organicmatter, total cation exchangecapacity, and pH generally decreasefrom west to east whileexchangeable cations and nutrientlevels are low throughout the region. A fellfield-drygraminoid-mesic environmental gradient was examinedon Grouse Ridge, Mt. Baker. High soil temperatureand low soil moistureregimes were typicalof the ridgetop fellfield.During droughtperiods, on the vegetatedportion of the slope, soil temperatures decreasedand soil moisturestress increased with distance downslope; a reflectionof increased plantcover and greaterevapotranspiration towards the base of the slope. Species at the base of the slope had reduced vigor and much lower leaf water potentialthan those upslope. Phenologicalpatterns were closely relatedto date of snowmeltand early-seasontemperature regimesalong the gradient. Key words: Alpine; British Columbia; high subalpine; microenvironment;North Cascades Range; phenology; plant communities; soils; species diversity; Washington; water relations.

INTRODUCTION ern Coast Range of BritishColumbia (Archer 1963; Brooke et al. 1970), and in the eastern North Cas- Alpine environmentshave interested some ecol- cades of British Columbia (McLean 1970). Lo- ogists for many years. These extreme environments calized or more general accounts of the vegetationor provide an excellent opportunityfor the study of flora have been provided for the Olympic Mountains species and communitypatterns. The patterns are (Peterson 1971), the western North Cascades of usually accentuated in alpine regions because of Washington (Franklin and Dyrness 1973; Krucke- topographic diversityand often change abruptlydue berg 1969; Douglas 1971; Douglas and Ballard 1971; to rapid shifts in environmentalgradients. Several Lowery 1972), the eastern North Cascades of Wash- other advantages of alpine vegetation studies are ington (Arno and Habeck 1972), the southernCoast the relativelysmall flora, the dwarfed stature of the Range of BritishColumbia (Brink 1959), and the in- plants, and the reduced communitystructure (Bliss teriorplateau region of south-centralBritish Colum- 1969). bia (Eady 1971). A general phytogeographicsurvey High mountainvegetation in the NorthwestPacific of northwesternNorth America has been presented Coast region has received attention only recently. by Schofield (1969). The rugged physiographyof the region, its inaccessi- This study examines the plant communitiesof the bility,and a frequentlyunfavorable summer climate alpine zone in the North Cascades of Washingtonand -have all contributedto this lack of ecological study. BritishColumbia. Because of its greateraccessibility Studies have been completed in the Olympic Moun- and general representativenessof the western North tains of Washington (Bliss 1969; Fonda and Bliss Cascades, a more detailed study 1969; Kuramoto and Bliss 1970), the westernNorth of microenvironment and plant response was conducted on Grouse Ridge, Cascades of Washington (Douglas 1972), the south- Mt. Baker. The objectives of the studywere to: (1) 1 Manuscriptreceived 30 October 1975; accepted 23 obtain quantitativeand qualitative data on the com- August1976. position,structure, and patternof the plant communi- 2 Douglas Ecological Consultants Present address: ties of the region; (2) obtain informationon the Ltd., 406-912 SelkirkAve., Victoria,British Columbia, Canada. soils associated with the major plant communities; 113

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(3) acquire mesoclimate data from several localities Geology and geomorphology in the region; (4) determine the interrelationships The complex geologic historyof the North Cas- between soils, climate, and plant communities and cades has been studied in some detail by Misch develop a comprehensiveclassification or ordination (1952, 1966). The oldest rocks are system for the alpine vegetation of the region; (5) crystallinebase- ment rocks (mainly gneisses). They predate the examine in detail several communities along an en- strata of sedimentaryand volcanic rocks, including vironmentalgradient in a localized area and compare Middle Devonian fossiliferous limestones. During them with regardto theircomposition, structure, pat- the Late Paleozoic Era, depositions of clastic sedi- tern, pedology, microclimate,phenology, physiology ments took place on the floor of a vast shallow sea. (water relations), and snowmelt pattern; and (6) These thick deposits were associated with a geosyn- relate the distributionof the North Cascadian alpine cline that extended from Alaska to California. The and high subalpine communities to other areas in clastic sedimentsinclude graywacke,shale, and sand- westernNorth America. stone. At this time, volcanic eruptions also con- tributedbasaltic and andesiticrocks to the deposition. STUDY AREA These ancient geosynclinal rocks were then meta- Location morphosed duringa period of compressionand fold- ing which occurred simultaneouslywith the with- The Cascade Range, extending from southern drawal of the sea during the Jurassic. Resulting Oregon to just north of the Washington-BritishCo- metamorphicrocks include slate, phyllite,schist, and lumbia border, can be subdivided into a number of greenschist. During Middle to early Late Cretaceous ecological provinces on the basis of geology, soils, time,major orogenyoccurred in the North Cascades. topography,climate, and vegetation. The northern- In the Tertiary, furtherdeposition, erosion, vol- most of these provinces, the western and eastern canism, and orogeny took place. Granites, diorites, North Cascade provinces (Douglas 1972), were quartz diorites,and granodioritesin the central and selected as the site of this study (Fig. 1). The area eastern parts of the range were formed. Final up- extends for about 130 km in a north-southdirection, lifting of the North Cascades took place in the encompassingabout 18,000 km2. Pliocene and subsequent weathering,mass wasting, The alpine zone is defined as that area above the and erosion contributedto the deeply dissected land- occurrenceof uprighttrees includingkrummholz and scape of today. Schist, gneiss, and granite outcrops some subalpine communities. This zonation system predominatethroughout most of the range. has been used in the Cascade Range of northern During late Pliocene and early Pleistocene times, and BritishColumbia and the St. Elias- Washington the volcanic cones of Mt. Baker and Glacier Peak Kluane Ranges of southwesternYukon by Douglas (3,712 and 3,181 m, respectively)were superimposed (1971, 1972, 1974) and differsonly slightlyfrom on the existingrange and other volcanic cones were (1957) and Meusel et that proposed by Dansereau formed (Coombs 1939). al. (1965) and recommended by Love (1970). Although the period of major volcanic activity Dansereau (1957), Meusel et al. (1965), and appears to have been at the beginningof the Pleisto- Love (1970), however, include the krummholz belt cene epoch, there were later eruptionsand flows. In withinthe subalpine zone. In contrast,a number of the North Cascades, ash layers originating from workers have included krummholzwithin the alpine Glacier Peak, Mt. Mazama, Mt. St. Helens have been zone (e.g., Clausen 1965; Bliss 1969; Krajina 1969; recognized. The oldest of these ashfalls is that from Kawano 1971; Franklin and Dyrness 1973). Vege- Glacier Peak 12,000 years before present (YBP) tational and floristicdata acquired duringthe present (Powers and Wilcox 1964). Additional eruptions study substantiatethe inclusion of krummholzwithin occurred more recently (ca. 6,600 YBP-Mt. the alpine zone, at least in the North Cascade Range. Mazama; 3,000 and 500 YBP-Mt. St. Helens; and The lower limit of the alpine zone ranges from 2,300 and 2,000 YBP-Mt. Rainier) (Wilcox 1965; 1,950 m on the west side of the range to 2,100 m on Westgate et al. 1969; Crandell et al. 1969). These the east side. The highestcontinuous cover of alpine deposits influencesoil horizonationin some areas. vegetationfound on the westernside was at 2,176 m. The continentalice sheet and alpine glaciers ad- Above this,and oftenat lower elevations,sheer rocky vanced and receded 2X in the North Cascades during slopes, snowfields,and glaciers restrictthe establish- the Salmon Springs Glaciation of the late Pleistocene ment of continuous vegetation. The upper limit of (early to middle Wisconsinan) (Crandell 1965). The continuousalpine vegetationincreases eastward,with broad, U-shaped valleys of the regionwere filledwith the highestcommunities at 2,600 m on the eastern ice during these advances. Evidence of this past side of the North Cascades. glaciation can be seen throughoutthe range in the

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TABLE 1. Climaticdata forweather stations in the Cas- representingthese types were then selected for sam- cade Rangea pling. The term "stand" refers to a particular ex- ample of vegetation that was sampled and "com- Total Mean precipitation temperature munity" or "community type" to a grouping of (cm) (OC) similar stands. A total of 209 stands, varying in June June size from 150 to 1,500 M2, were sampled on 39 Weather Elevation to to mountains in the study area (Fig. 1). The com- station (m) Annual AugustAnnual August munitytypes were sampled by 4 to 10 stands. Rock Diablo Dam 272 189 14 9 17 outcrops and streamsideswere not sampled. Winthrop 535 37 6 7 19 For the regional survey, in examining all but the StevensPass 1,245 192 15 4 12 Mt. Baker 1,265 280 28 5 12 krummholzstands, twenty 20 X 50 cm quadrats were AllisonPass 1,341 175 12 3 13 set out perpendicularto the slope contours by a re- Mt. Rainier" 1,691 253 13 4 11 strictedrandom technique (Bliss 1963) in a 5 X 10 NickelPlate 1,768 60 15 2 10 m area. Numerous alpine studies in North America a Data fromBritish Columbia Departmentof Agricul- have shown this to provide a sample of adequate ture (1963) and U.S. WeatherBureau (no dates). 'The MountRainier (Paradise) stationis located 120 size, including nearly all species in a stand. Crown kmsouth of thestudy area. cover, using the methods and cover classes of Daubenmire (1959, 1968), was estimated by strata for all plant species (except cryptogams on rocks form of cirques, jagged ridges, steep-walled valleys, and trees) in each quadrat. Additional species, which and the rounded tops of the lower mountains. Nu- occurred outside the quadrats but withinthe stands, merous, relativelysmall remnantsof the once exten- were also tallied. Frequency and average cover for sive alpine glaciers still remain in the region. each species were calculated and converted to More recentlyalpine glaciers (Fraser Glaciation- prominence values (PV) by multiplyingthe average ca. 25,000 YBP and Neoglaciation-ca. 2,000 YBP), percentage cover by the square root of the species continental ice advance (ca. 15,000-13,000 YBP), frequency in each stand. This modified index of and the Hypsithermal Interval (ca. 10,000-5,000 Beals (1960) provides a method by which cover and YBP) have furthermodified the landscape. frequencymay be combined into a single value for use in equations and more easily interpretedtables. Climate Sampling replications were repeated three times in each of three stands, all differingin composition The climate of the North Cascades varies consider- and structure. The replications indicated that, for ably from maritime on the western slopes to more all of the most prominent species, sampling was continentalon the eastern slopes. Due to the pre- within + 14% of the mean prominence value for vailing westerliesfrom the Pacific Ocean crossingthe communitieswith continuous plant cover and ?26% mountain massif, annual and summer (June to for species in communities with discontinuous August) precipitationis considerably lower on the (boulderfield and fellfield) cover. The average co- eastern than on the western slopes (Table 1). The efficient of similarity was also computed for the subalpine Mt. Baker station is probably representa- replicatesusing the formulac = 2w/ (a + b) X 100 tive of conditions on the westernslopes with a mean (Gleason 1920), where w is the sum of the lowest annual precipitationof 280 cm and a mean summer prominencevalues of species common to both stands, Plate precipitationof 28 cm. The subalpine Nickel and a and b are the total prominence values of all is station, on the eastern flanks of the Cascades, species in stands a and b. Replicated samples from in probably representativeof conditions that region the same stand had average similaritycoefficients (mean annual precipitation of 60 cm and a mean of 0.78 to 0.81 when plant cover was continuous, of 15 cm). summerprecipitation whereas the average fellfieldsimilarity coefficient was only 0.47. Sampling adequacy also met the "minimal METHODS area" criteria (Cain 1938). Sampling was termi- Vegetation nated, in almost all cases, well after the plateau in the species-area curve was reached. Minimum stand A general reconnaissance of the alpine zone of size was 150 M2. Krummholz stands were ex- the North Cascades was made in early summer amined by a "releve" method, since their size and 1970, and during a previous study (Douglas 1972). From this survey,tentative plant communitytypes, floristiccomposition were extremelyvariable. Each recognized by their dominant species and plant stand was divided into four equal quarters and the structure,were delimited. Relatively homogeneous crown cover for all species was estimated by visual stands (with respect to floristicsand plant structure) observationin each quarter. Forty-twostands, vary-

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 117 ing in size from 25 to 100 M2, were treated in this (Bouyoucos 1951); pH using a saturated paste manner. (Doughty 1941); and organic matterby the Walkley- A thirdsampling procedure was used for analysis Black wet oxidation method (Walkley and Black of species distributionalong a 65 X 7 m belt transect 1934). Exchangeable cations were extracted with on Grouse Ridge, Mt. Baker. At 2-m intervalsdown neutral N ammonium acetate and determined by the slope, five 20 X 50 cm quadrats (from a possible atomic absorption spectrophotometry.Levels of ni- 10), were randomly selected and set out at 5-dm trogen,phosphorus, and potassium were determined intervals along and perpendicular to the slope con- at the Alberta Soil and Feed Testing Laboratory: tours. nitrogen was determined by the phenoldisulfonic Similaritycoefficients (C = 2w/(a + b) X 100) method; phosphorus by the combined nitric acid- between stands were computed. Species were not vanadate-molybdatecalorimetric method; and potas- adjusted in relation to their maximum values of fre- sium was extractedwith N ammonium acetate at pH quency and cover as in Bray and Curtis (1957). Dis- 7.0 and determinedby flame photometry.Soil color similarityvalues (1 - C) were then computed and was described for moist soil using the Munsell Color used for the constructionof two-dimensionalordina- Charts in naturallight. tions (Bray and Curtis 1957; Beals 1960). The ordinationsallowed the groupingof stands into com- Microenvironment munity types that correlated with several environ- Because of the large climate gradient across the mental gradients. Several agglomerativehierarchical mountains,summer mesoenvironment(i.e., tempera- clustering techniques (Pritchard and Anderson ture, atmospheric moisture,solar radiation, precipi- 1971), were also used for syntheses of herbfield, tation, and wind) in the North Cascades was moni- boulderfield, fellfield, and vegetation stripe com- tored at five differentlocations (Fig. 1) during the munities. Community types are named after the summers of 1970 through 1972 at approximately one or two major dominants. weekly intervals. Temperature and atmospheric Nomenclature, authorities,and taxonomy follows moisturewere monitoredwith Belfortand Lambrecht Hitchcock and Cronquist (1973) for the vascular hygrothermographsplaced in white-painted,louvered plants, Lawton (1971) for mosses, Schofield (1968) shelterswith sensors between 5 and 25 cm above the for hepatics, and Hale and Culberson (1970) for ground. Solar radiation was measured with Rabitsch lichens, with the following exceptions. The lichens actinographs set with sensors 10 cm above and Cladonia gracilis (L.) Willd. and Peltigera canina parallel to the soil surface. Precipitationwas mea- (L.) Willd. were not treated at the varietal level sured withTrucheck?) rain gauges set at 60 cm above since thevariants were oftenindistinguishable. Tham- nolia vermicularis (Sw.) Ach. ex Schaer, has been and parallel to the soil surface. Wind was monitored included with Thamnolia subuliformis (Ehrh.) W. with Belfort three-cup totalizing anemometers with Culb. Chemical tests revealed that 25% of all ma- cups placed 60 cm above the ground. These sensor terial collected was Thamnolia vermicularis. In the positions were used to enable comparisons with data from previous studies and because of the physical text only the binomial is used for any plant having limitationsof the instrumentsused. just one variant in the North Cascades. A full set Microenvironmentwas monitoredduring the study of voucher specimens has been placed in the Univer- period along the environmentalgradient on Grouse sity of Alberta herbarium (ALTA). Partial sets are Ridge. Four stationswere established at 15- to 25-m in the Department of Agriculture(Ottawa) (DAO), intervals for a distance of 61 m down the slope. New York Botanical Garden (N.Y.), U.S. Forest Soil and air temperatures were measured with Service (Fort Collins, Colorado), University of laboratory-calibratedRCATM 1N2326 diodes, set in Washington (WTU), and Western WashingtonState #3M ScotchcastTm No. 10 electrical resin. Soil College herbaria. temperaturediodes were placed in 13 mm (outside diameter) aluminium pipe probes, sealed off, and Soils buried horizontallyat depths of 2, 10, 20, and 30 cm. Air temperaturediodes were placed in double- Soil pits were dug in 16 representativecommuni- shielded, open aluminum tubes, painted white out- ties across the North Cascades and composite samples side and silver inside. These diodes were located at collected from each described horizon. Seven addi- heightsof either 5 and 15 cm or 10 and 20 cm; the tional pits were dug along the environmentalgradient latter heights being used for the taller vegetation at on Grouse Ridge. Samples were collected from two the base of the slope. Resistances were measured additional soil pits opened by Bockheim (1972). with a bridge meter powered by a mercurybattery Laboratory analyses of the fine (<2 mm) fraction cell. Field measurements were precise within included: texture by the hydrometer method +0.50C. Coleman soil moisture blocks (Coleman

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions 118 GEORGE W. DOUGLAS AND L. C. BLISS EcologicalMonographs Vol. 47, No. 2 and Hendrix 1949) were positioned in the same Snowbed communitytypes.-Six communitytypes pits with the diodes at depths of 10 and 20 cm or in the North Cascades are consistentlyassociated 10 and 30 cm, the lower depth was determinedby with snowbed habitats. Several others, are not re- depth of the root system. Soil moisture was also strictedexclusively to snowbeds, but occur in them determined periodically (approximately monthly) in at least part of their range. They are discussed with gravimetricsamples taken at the same depths withinthe shrub communitytypes. and within 2 m of the Coleman blocks. Available a) Saxifraga tolmiei-Luzula piperi community. soil moisture(0.3 and 15 bars) was determinedfrom This communityoccurs on gentleto moderatelysteep, desorption curves run on the <2 mm soil fraction. mainly southerlyslopes in the western North Cas- Temperatures and soil moisture data, except during cades (Fig. 3). Snow remains untillate Julyor early July 1972, were collected at approximatelyweekly August. Soils are poorly developed, poor to fairly intervals. well drained, and show indicationsof surficialmove- ment. A similarhabitat and plant communityoccurs Phenology in the subalpine zone of the westernNorth Cascades Phenological stations were established at 10-m (Douglas 1972). intervals along the 70-m belt transect on Grouse The Saxifraga-Luzula communityis characterized Ridge. Phenological notes were taken on 32 species by a low average total plant cover and few species at weekly intervalsduring 1971 and bi- to tri-weekly per stand (Tables 2 and 3). Saxifraga tolmiei and intervalsduring 1972. Observations,within a 2 X 2 Luzula piperi are the only constant species. Other m plot at each station,included the followingphases: less prominent plants are Carex pyrenaica, Juncus vegetative, flowering, fruiting,seed dispersal, and drummondii,and the bryophytes,Polytrichum sex- dormancy. angulare and Marsupella brevissima. b) Eriogonum pyrolaefolium-Luzula piperi com- Plant water relations munity. In the central North Cascades (Fig. 3), Leaf water potential (ifr) was determined in the this community type is most commonly found on field during 1971 for 10 species on Grouse Ridge slight to moderately steep, northern slopes. This with a portable pressure chamber (Scholander et al. habitat is similarto that of the Saxitraga-Luzula type 1964). found fartherwest. Snowmelt is late (early to late Leafy stems or leaves cut at the petiole were put July) and soil surfaces are unstable. These sites, in directlyinto plastic bags from which all possible air contrast to the Saxifraga-Luzula habitat, are well was expressed. The bags were sealed, kept at ambi- drained and have a lower soil moisturecontent in late ent temperatureout of directsunlight, then measured summer. within0.5 h of cutting. This procedure had little,if This communitytype, with low average total plant any, effect on leaf f (Hickman 1970). Measure- cover and relativelyfew species, is the most sparsely ments were made between 1300 and 1500 h and at vegetated of all the alpine communities examined. 2400 h, times of near minimum and maximum leaf Eriogonum pyrolaefoliumand Luzula piperi are the A, respectively(Hickman 1970; Kuramoto and Bliss only constantspecies. 1970). c) Carex nigricanscommunity. Concave to level, poorly drained sites are typical of this community RESULTS throughoutits westernto central range in the North Regional vegetation Cascades (Fig. 3). This type has the greatestsnow accumulation and shortest snow-free period of all Two-dimensional ordinations were constructed, habitats in the region,with snow persistinguntil late usingprominence values, to provide an understanding July or early August, or in years of high snowfall, of alpine communityrelationships and patterns(Fig. early September. Soils are poorly drained and re- 2). Since high beta diversity,or a high degree of main moist for most of the summer. This type is also compositional change between communities along common in the subalpine zone of the westernNorth gradients (Whittaker 1960), reduces ordinationper- Cascades. formance (Gauch and Whittaker 1972) the North Cascadian communitieswere treated as three sepa- Carex nigricansforms a low, dominantmat with a rate regions (west, central, and east). Although the high average cover and frequency. Other prominent ordinationsare based only upon floristicdissimilari- species are Luetkea pectinata and Deschampsia ties between sample stands, the stand groupings or atropurpurea (Table 2). Polytrichadelphus lyallii, communitytypes do indicate some general environ- Kiaeria blyttii,Lescuraea radicosa, and the lichen mental relationships. Time of snowmelt is the most Lepraria neglecta are importantcryptograms. obvious environmentalfactor illustratedby the ordi- d) Antennaria lanata community. This type is nations (Fig. 2). found from the central to eastern North Cascades

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(Fig. 3) in snowbed habitats similar to those of the Carex nigricanstype. In the central North Cascades, EMP where the ranges overlap, the two communitiesmay WEST be found adjacent to each other. The Antennaria type, however, becomes snow-free2 to 4 wk earlier (late Juneto late July) and since the soils have better PHG SAC drainage, the sites become drier during late summer. -. - * SAR Plant cover of the Antennaria communityis simi- CAS PHE A RCH lar to that of the Carex nigricans communitybut a greater contributionis made by mosses and lichens in the former. The Antennaria community is also floristicallyricher. Antennaria lanata has a high frequency and a moderate mean cover. Carex nigricans and Leutkea pectinata are importantcomponents in the central North Cascades with Salix cascadensis and Carex scirpoidea var. pseudoscirpoidea becom- ing prominent farthereast. Polytrichum piliferum and Lepraria neglecta are common cryptograms throughoutthe range whereas Cetraria islandica is importantin the eastern North Cascades. LUPP e) Carex brewericommunity. This snowbed type Y CNA occurs mainly in concave sites in the eastern North C ENTRAL E-=L\ Cascades although several stands were encountered on slightslopes just south of Glacier Peak (Fig. 3). These well-drained sites are snow-freeby the latter ~~~~~ part of July,and become dry duringlate summer. A 9 DR~DY large number of xerophytic species (e.g., Carex FES aC scirpoidea var. pseudoscirpoidea,Carex nardina, etc.) occur here. Carex breweri has a moderate average cover and a high frequencyin this floristicallyrich community. Y CNA Erigeron aureus, Lupinus lepidus var. lobbii, and CNI EM/PCB ANT Danthonia intermediaoccur withmoderate frequency and relativelylow cover. Prominentcryptogams are Polytrichumpiliferum, Kiaeria blyttii,Lepraria ne- j)CBR glecta, and Cetraria islandica (Table 2). f) Carex capitata community. This is a common x type at higher elevations (2,300 m to 2,450 m) in

DRY EAST FIG. 2. Ordinationof 128 stands in the alpine zone of the NorthCascades. The standsare includedin three SAC CNA ordinationsaccording to region(west, central, and east). * ~ ~ (D SAR Lines delimitcommunity types whose names are derived PHG fromthe dominantspecies. Abbreviations:S-L-Saxif- raga tolmiei-Luzulapiperi; E-L-Eriogonum pyrolaefolium-Luzulapiperi; CNI-Carex nigricans; ANT- Y ANT CC .C A ntennarialanata; CBR-Carex breweri;CCA-Carex PH capitata; LUP-Lupinus latifolius;FES-Festuca viridula; CAS-Cassiope mertensiana;PHE-Phyllodoce em- * . :*. KOM petriformis;PHG-Phyllodoce glandulifloria;ARC- * CBR j CAL Arctostaphylosuva-ursi; EMP-Empetrum nigrum;SAR -Salix nivalis; SAC-Salix cascadensis; DRY-Dryas CsR octopetala; DAN-Danthonia intermedia;CAL-Cala- magrostispurpurascens; CSP-Carex spectabilis; CPH- * AN Carex phaeocephala;CSR-Carex scirpoideavar. pseudoscirpoidea; CNA-Carex nardina; KOM-Kobresia myosuroides. x

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions TABLE 2. Compositionof plantcommunity types in the alpinezone of theNorth Cascades Range. Data are forprominence value indices

VASCULAR SPECIES Saxifraga tolmiei 135 Luzula piperi 46 18 14 2 13 12 1 1 T 2 Carex pyrenacia 26 4 1 9 Juncusdrummondii 12 21 8 1 Carex nigricans 5 733 26 1 7 14 T Phyllodoce empetriformis 1 4 38 307 Carex spectabilis 1 2 13 180 10 19 136 4 3 547 1 T Luetkea pectinata 1 261 28 23 102 16 33 Hieracium gracile T 8 T 13 T 2 1 6 1 m Vaccinium deliciosum T 91 64 68 58 2 ? Eriogonum pyrolaefolium 46 Erigeronaureus 4 1 60 5 T 10 T 3 14 17 5 1 2 1 6 22 7 m Poa sandbergii 2 P T 6 10 2 T 1 8 4 14 19 Antennarialanata 1 31 346 22 14 18 63 43 42 4 9 2 12 2 Sibbaldia procumbens 1 7 7 8 T 1 5 22 8 T T 1 38 3 2 1 1 r Haplopappuslyallii T 6 P T T 1 2 T T 12 3 7 4 18 0 Agoserisglaucavar. T 3 59 4 2 2 3 15 12 P T dasycephala Sedumlanceolatum var. T 3 5 1 T T 3 1 4 8 10 9 1 2 21 7 10 2 > lanceolatum Festucaovinavar. T 8 20 52 3 8 4 22 9 31 43 13 13 40 20 40 52 31 39 D brevifolia Antennariaalpina P 21 15 T T T 8 4 3 30 11 2 18 Deschampsia atropurpurea 75 T 15 2 T T Erigeron peregrinus 35 49 4 3 9 3 2 var. scaposus Veronica cusickii 2 4 1 28 8 2 T 1 Phyllodoce glanduliflora 1 2 13 83 7 352 27 P P T - Potentilla flabellifolia 1 25 58 T 1 Salix cascadensis 108 62 19 15 2 246 P Carex scirpoidea var. 75 25 51 T 14 13 5 T 232 210 80 346 2 120 pseudoscirpoidea Arenariacapillaris 18 11 14 60 T 8 12 1 1 7 3 T 104 T 22 31 P T Arenariaobtusiloba 21 10 11 1 9 16 12 16 71 100 56 48 30 74 Carex breweri 20 317 3 67 5 Luzula spicata 11 2 7 1 T T 2 3 2 T 3 10 4 25 30 7 8 Carex phaeocephala 13 20 28 1 P 2 1 16 2 2 3 19 261 91 15 1 ' Cassiope mertensiana 3 4 408 75 2 T ? Trisetumspicatum 2 6 11 4 3 T 2 1 3 11 9 T 3 10 1 6 14 2 29 . Stellaria longipes 1 T 11 T 8 3 T 6 5 7 17 T 12 ~~o Potentilla diversifolia 2 39 136 15 3 1 T 14 14 5 2 221 85 5 73 105 2 73 var. diversifolia k)c~~

~~This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions TABLE 2. Continued~~

CommunitytypeSa~be S-L E-L CNI ANT CBR CCA LUP FES CAS PHE PHG ARC EMP SAR SAC DRY DAN CAL CSP CPH CSR CNA KOM Species (4) (4) (4) (5) (5) (5) (6) (4) (8) (5) (5) (4) (7) (5) (9) (10) (5) (5) (4) (7) (5) (5) (6) 58 Lupinus lepidus var.lobbii T 55 T T 26 23 19 5 17 T T T 13 1 14 214 T T 7 Dryas octopetala 1 Carex pachystachya P T 40 1 41 1 41 8 559 55 T 27 T Danthonia intermedia 53 Solidagomultiradiata 20 76 20 4 6 7 8 1 1 33 14 155 21 14 Sileneacaulis 10 1 1 T T 1 5 P 2 6 1 7 Phlox hendersonii 9 57 Agrostisvariabilis 6 12 11 4 T 1 1 1 1 15 4 33 T T 1 11I 1 2 Polygonum viviparum 1 Achillea millefolium 3 T 2 4 P 8 19 40 8 13 var.alpicola Carex capitata 2 569 10 4 1 8 6 P Vaccinium caespitosum, 2 2 1 4 2 11 1 T 10 3 18 T 179 T Carex nardina 9 Erigeron compositus 1 4 3 2 2 2 11 var.glabratus Smelowskia ovalis 1 16 T 1 4 T 29 I Salix nivalis T 6 16 299 1 T 2 78 T 6 4 3 503 T P Empetrumnigrum 423 Kobresia Myosuroides T 4 T P Cerastium arvense T 1 T 47 2 4 T Oxytropiscampestris 14 16 36 P 2 46 105 P 30 11 78 var.gracilisZ Antennaria umbrinella 12 1 6 17 13 1 10 18 2 3 T T 1 T 6 2 T 7 T 9 22 3 1 Penstenmonprocerus 0 Calamagrostis purpurascens T T 3 2 379 3 P 2 P Sedum roseum T T T P 10 Lupinus latifolius 622 59 6 1 1 5 3 var.subalpinus Polygonumbistortoides 163 24 1 3 18 4 38 Festucaviridula 81 474 3- Valerianasitchensis 46 i Phloxdiffusa 26 4 2 9 2 5 2 T 216 33 A nemone occidentalis 17 T 2 Aster foliaceus 12 T var.foliaceus Juncusparryi 9 56 5 5 Vaccinium scoparium 5 1 1 38 P Erythroniumgrandiflorum 2 26 Pedicularis contorta 2 4 T 14 Artemisianorvegica 55 Arnicarydbergii 33 Pedicularis racemosa 14 var.racemosa A rctostaphylosuva-ursi 1 615 3 T T

~~This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions TABLE 2. Continued~~

Communitytypesa be S-L E-L CNI ANT CBR CCA LUP FES CAS PHE PHG ARC EMP SAR SAC DRY DAN CAL CSP CPH CSR CNA KOM Species (4) (4) (4) (5) (5) (5) (6) (4) (8) (5) (5) (4) (7) (5) (9) (10) (5) (5) (4) (7) (5) (5) (6) Lycopodium alpinum 15 Carex albonigra 13 T 3 5 1 T 4 1 Campanula rotundifolia P 6 T 37 1 Cassiope stelleriana 19 Agrostisscabra 1 T 11 1 Silene douglasii 14 3 1

BRYOPHYTES Polytrichumsexangulare 10 11 T Marsupella brevissima 10 m Pohlianutans 1 T 18 1 T T 1 Polytrichumpiliferum 8 4 161 128 4 1 8 19 50 44 T 12 9 68 10 20 T 123 53 19 7 2 x Rhacomitriumcanescens 2 T 1 5 1 11 T 2 1 1 m var. ericoides Polytrichumjuniperinum 1 50 6 85 T 6 12 1 19 4 T 39 28 2 20 4 18 35 Polytrichadelphuslyallii 74 2 22 2 T T Kiaeria blyttii 36 70 2 5 Lescuraea radicosa 24 1 Dicranum spadiceum 14 Bryumcf. angustirete 11 3 4 3 T 1 4 2 Desmatodon latifolius 3 T 18 T I T 10 4 T > var. latifolius Tortula ruralis 1 21 2 10 1 37 5 18 22 65 25 96 z Aulacomnium palustre 1 12 Dicranum muehlenbeckii 87 4 Drepanocladus uncinatus 29 T T Bryumcf. pallens 15 1 Ceratodon purpureus 4 5 8 1 T 14 1 Bryumcaespiticum 1 T 1 5 T 3 2 15 t Dicranum fuscescens T 37 Dicranum scoparium 33 2 1 12 z Dicranum tauricum T 10 T Heterocladium dimorphum 1 12 T Bryum weigelii 43

LICHENS Leprarianeglecta T 4 69 171 87 T 87 18 48 26 34 9 2 4 T 10 Cladoniagracilis T T 3 4 2 3 T 11 1 1 T T 139 41 Cladoniapyxidata T 33 24 39 T 4 1 9 2 13 3 23 36 14 43 29 12 59 Cladoniasp. T 11 1 7 1 1 6 25 2 2 4 10 Cetrariaislandica P T 56 35 13 25 1 86 1 41 28 34 10 31 31 12 37 T 36 Peltigeracanina P 10 8 21 1 T 3 3 10 T 9 6 11 5 5 19 5 29 3 9 Solorina crocea P 4 16 T P T T 2 T Cladoniaecmocyna T 8 1 20 5 T 4 4 T 1 T T T T Stereocaulonalpinum 16 2 3 9 7 16 1 6 20 T T zm Lecidea granulosa 15 2 T T 5 34

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Communitytypesa b'e S-L E-L CNI ANT CBR CCA LUP FES CAS PHE PHG ARC EMP SAR SAC DRY DAN CAL CSP CPH CSR CNA KOM SPeCieS (4) (4) (4) (5) (5) (5) (6) (4) (8) (5) (5) (4) (7) (5) (9) (10) (5) (5) (4) (7) (5) (5) (6) Cetrarianivalis 1 12 8 3 T 16 4 8 5 25 T 3 16 1 24 Thamnolia subuliformis T 16 10 T 8 T 8 22 9 11 11 22 12 40 11 33 24 Cornicularia aculeata 17 T 3 T 21 9 12 6 44 T 15 8 46 16 Candelariellasp. 3 4 1 T 4 3 20 1 Lecidea rutonigra 1 T T 2 3 1 11 Cladina mitis 1 6 1 7 T 24 T 5 4 4 T 81 38 Ochrolechia upsaliensis T T T 2 T T 3 16 T 1 17 4 3 Buellia epigaea T 2 1 1 T 2 22 1 e Cetraria ericetorum 40 T 13 19 1 T 12 32 54 38 14 1 30 z Cetrariacucullata 1 T T 26 2 5 55 Cladoniabellidiflora T 6 11 T Cladoniasubsquamosa 17 T Z Cladoniacoccifera 21 AVERAGECOVER (%,) C) Vascular species 29 14 126 82 82 127 192 120 89 76 73 114 81 63 44 40 194 146 149 99 113 57 148 19 6 23 = Bryophytes 4 2 18 26 23 35 2 3 4 11 11 2 3 8 10 2 12 6 22 13 Lichens 1 8 29 26 17 3 11 17 8 30 3 14 20 19 9 13 28 39 31 24 20 24 C Bareground 21 58 2 4 11 4 9 26 12 12 16 13 19 12 25 19 5 6 16 9 7 26 3 C Rocks 56 27 1 5 1 6 7 6 6 1 21 9 41 6 15 10 6 15 8 ; AlIplants 33 17 152 137 131 189 197 124 110 95 114 119 98 91 73 51 219 180 210 143 156 83 178 e (X + SD) ?11 +2 +47 +39 +43 ?38 +36 +28 +25 +4 ?45 +31 +30 +48 +17 ?15 +13 +13 +35 +45 +35 +17 +25 Z

TOTAL NUMBER OF SPECIES 42 0 Vascularspecies 10 21 15 37 46 36 48 39 35 35 51 44 42 51 46 48 42 44 35 61 43 44 7 g Bryophytes 6 3 6 6 10 14 2 6 9 6 7 5 6 15 11 4 7 6 13 18 13 8 Lichens 2 8 7 14 18 20 6 2 12 15 24 10 13 16 22 25 16 14 13 22 23 18 17 g 66 AlIplants 18 32 28 57 74 70 56 47 56 56 82 59 61 82 79 77 65 64 61 101 79 70 H AVERAGE NUMBER OF SPECIES Vascular species 5 12 9 15 16 20 17 24 13 14 17 18 12 22 16 17 25 25 18 21 22 20 27 T 6 Bryophytes 2 2 2 3 4 6 0 2 3 3 3 2 2 4 3 2 3 4 5 4 4 2 Lichens 1 2 2 7 7 9 1 1 4 6 10 3 4 12 10 10 8 12 7 9 9 10 12 44 AlIplants 8 15 14 25 27 35 18 27 20 22 30 23 18 38 28 28 36 41 30 34 35 32 +7 +3 +6 (X 4- SD) -+?2 +8 ?5 ?5 ?14 ?6 +3 +6 +3 +4 +6 +12 +6 +8 +6 +6 +8 +7 +4 +7 a Abbreviations:S-L-Saxifraga tolmiei-Luzulapiperi, E-L-Eriogonum pyrolaejolium-Luzulapiperi, CNI-Carex nigricans,ANT-Antennaria lanata,CBR-Carex breweri,CCA-Carex capitata,LUP-Lupinus latifolius,FES-Festuca visidula,CAS-Cassiope mertensiana,PHE-Phyllodoce empetriformis,PHG-Phyllodoce glanduliflora,ARC-Arctostaphylos uva-ursi, EMP-Empetrum nigrum,SAR-Salix nivalis,SAC-Salix cascadensis,DRY-Dryas octopetala,DAN-Dantonia intermedia,CAL-Calamagrostis purpurascens,CSP-Carex spectabilis,CPH-Carex phaeocephala,CSR-Carex scirpoideavar. pseudoscirpoidea,CNA-Carex nardina, KOM-Kobresia myosuroides; T (trace) indicates a mean prominence value of less than 0.5, P (present) indicates that a species was present but not tallied in the communitytype. b Number of stands sampled are enclosed in parentheses. COnly those species with a prominence value of 10, or more, in at least one communitytype are included in this table.

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions 124 GEORGE W. DOUGLAS AND L. C. BLISS Ecological Monographs Vol. 47, No. 2 TABLE 3. Summaryof communitycharacteristics for alpine and high subalpinecommunities, Northern Cascades Range Mean Mean fre- Mean Eleva- Total Mean cover quency total Regiona tion Snow- no. no. (domi- (domi- plant Community range As- melt spe- spe- nants) nants) cover type W C E (m) pect date cies cies (%) (%) (%) Saxifraga tolmiei- Late Jul- 15?+ 8 78 ? 17 Luzula piperi X 1,750-2,100 South earlyAug 18 8? 2 7? 6 35?24 33?11 Eriogonum pyrola folium-Luzula Early- 6?+ 1 68 ? 17 piperi X 2,000-2,200 North lateJul 32 15? 8 3? 0 29? 15 17+ 2 Carex nigricans X X 1,750-2,100 All Late Jul- earlyAug 28 14? 5 75? 18 95?410 152+47 A ntennarialanata X X 2,000-2,200 All Late Jun- lateJul 57 25? 5 35?15 100? 0 137+39 Carexbreweri X X 2,100-2,300 All Late Jun- lateJul 74 27?414 32?411 92?415 131?+43 Carexcapitata X 2,300-2,450 All Early- lateJun 70 35? 6 57?15 100? 0 189?38 Lupinuslatifolius x x 1,750-2,150 South Late May- earlyJun 56 18? 3 62?15 100? 0 197+36 Festucaviridula X 1,850-2,150 South Late May- earlyJun 47 27? 6 48?412 96? 9 124?28 Cassiope Early Jun- mertensiana x x 1,750-2,150 South earlyJul 56 20? 3 42?411 94? 7 110+25 Pyllodoce Early Jun- empetriformis X X X 1,750-2,150 South earlyJul 56 22? 4 34? 8 82? 10 95+ 4 Plhyllodoce Early Jun- glanduliflora X X X 1,800-2,400 All lateJul 82 30? 6 36?22 89?14 114?45 A rctostaphylos Late May- uva-ursi X X X 1,750-2,250 South midJun 59 23?12 63?22 92?15 119?31 Empetruni nigrum X X 1,750-2,100 South- Late May- West mid-Jun 61 18? 6b 52? 18 94?410 98?30 Salix nivalis X X X 1,900-2,400 South Mid-May- earlyJun 82 38? 8 31?16 92?12 91?48 Salix cascadensis X X X 1,900-2,450 All Mid-May- earlyJun 79 28? 8 27?10 83?14 73?17 Dryas octopetala X X 2,100-2,450 All Early- late May 77 28? 6 23? 7 80?11 51+15 Danthonia Mid-May- intermedia X 2,100-2,350 All earlyJun 65 36? 8 56?10 99? 2 219+13 Calamagrostis South- April- purpurascens X 2,250-2,600 West earlyMay 64 41? 7 38? 6 97? 4 180?+13 Carexspectabilis X 1,750-2,175 South Mid-May- earlyJun 61 30? 4 55+16 100? 0 210?35 Carex plhaeocephlala X X X 1,850-2,400 All Early- late May 101 34? 7 27?10 94? 7 143?45 Carexscirpoidea X 2,200-2,600 All Mid-Apr- earlyMay 79 35? 7 36?14 94?11 156+35 Carex nardinia x 2,200-2,600 All Late-Apr- earlyMay 70 32?4 3 19?4 5 94?+ 7 83?-17 Kobresia Essentially 9--4 18+2 myosuroides x 2,250-2,600 All snowfree 66 44 6 43 154 17825 W - west,C = central,E = east. Average? standarddeviation.

the eastern North Cascades (Fig. 3) where it occurs generallyhas the least snow accumulation and is the in level to slightlyconcave sites, often with hum- first to become snow-free (June). Soils, due to mocky topography (Fig. 4). Of all the snowbed drainage from upslope, remain moist well into the types in the region, the Carex capitata community summer.

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WEST ICENTRALI EAST WEST ICENTRAL| EAST SNOWY SNOWY - _ A MTN. B___B.C*:C___ A MTN. B.C.AB C : WASHP1 wASH-: :I MT BAKER : BAKER : A g *SLATE PEAK **A MT. A SAEPASLATE PEAK 0~~~~*A~~ ~~~000 TIFFANY I f *. * TIFFATNYI ...0 TIFFANY MTN- 0**: MTN. 0.

~~GLACIER PEAK. STAR PEAK IGLACIER PEAK SAR PEAK~~

~~N 0**0- CAREX PHAEOCEPHALA, PHYLLODOCE - - - CAREX SPECTABILIS EMPETRIFORMIS, P. GLANDULIFLORA, 50 KM SAXIFRAGA TOLMIEI- ARCTOSTAPHYLOS UVA-URSI, SALIX LUZULA PIPERI NIVALIS, S- CASCADENSIS SCALE~~

~~SNOWY SNOWY B.C. MTNB-C. MTN- A - .,- - ~~-em~ ~ ~ W~~ WASH.: :SH : AMT.BAKER MT BAKER \> CIER PEAK * SLATEPEAK M A ,KE ST PEAK A :; to A 0 .IFNY TIFSNY~~

GLACIER PEAK : S.TARPEAK GLACIER PEAK STAR PEAK lo AO OIA 0 :~~~~~~~~~~~~~~~~~~~~~~~1 IO, 0 CAREX NIGRICANS,EMPETRUM *e. FESTUCA VIRIDULA t~~~OBM-T'N- NIGRUM, LuPINUS LATIFOLIUS, -XW ERIOGONUMrT PYROLAEFOLIUM| S CASSIOPE MERTENSIANA LUZULA PIPER I

* SNOWY I SNOWY A MTN B.C. N R AMTN. B.C. * I WASH. I WASH.3.H of mI c tys: i te a H zn MT- BAKER 1: MT BAKER * A 1SLATE PEAK A : SLATE PEAK I1A ** KO A %~/ 00 TIFFANY *0 %.-TIFFANY / ~~~'MTN- MTN

, SIAR EKSTAR PEAK GLACIER PEAK STAs PEKGLACIER PEAK lo'sA *1 A - -- CAREX SCIRPOIDEA, C. CAPITATA, DANTHONIA INTE RMEDIA, CALAMAGROSTIS - -- ANTENNARIA LANATA PURPURASCENS, KoBRESIA MYOSUROIDES *****0CAREX BREWER1, C. NARDINA ***** DRYAS OCTOPETALA

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~~* *~~

FIG. 5. A Lupinus latifoliuscommunity at 1980 m on GlacierPeak, Washington.The Empetrumnigrum FIo. 4. A Carex capitata communityat 2,380 m on occurson theadjacent upper slopes. Arnold Peak, Washington.The Carex scirpoidea var. pseudoscirpoideacommunity covers the extensiveslopes in the background. b) Festuca viridulacommunity. This community type is apparentlyrestricted to lower elevations Communitiesof this type have a high average (1,850 m to 2,150 m) on southern,well-drained total plant cover, includingthe highest average slopesin thecentral North Cascades (Fig. 3). These bryophytecover of any snowbedcommunity in the slopes become free of snow about the same time region(Table 2). Carex capitata has a high mean as in theLupinus habitats but soils become drier dur- cover and frequency.Important vascular plants in ing late summer. This communityis floristically this floristicallyrich communityare Potentilla di- similarto thosein the subalpine. Because of its oc- versifolia var. diversifolia, Solidago multiradiata, currenceonly in the loweralpine zone, it may best Salix cascadensis, Festuca ovina var. brevifolia and be considereda highsubalpine community. Carex scirpoidea var. pseudoscirpoidea (Table 2). This communityis closelyrelated to the Lupinus Prominentmosses and lichensare Dicranum muehlen- typewith a largenumber of speciescommon to both beckii, Polytrichumjunipernum, Cetraria ericetorum, (Table 2). Total vascular plant cover is much and Cladonia pyxidata. lower,however, and the averagenumber of species Mesic herb communitytypes.-Two of the North per stand is greaterin the Festuca viridulatype. Cascadianalpine communities are includedwithin the Festuca has a relativelyhigh average cover and mesic herb types. These communitiesare charac- frequency.Other importantplants are Antennaria terizedby a densecover of herbsand usuallylack a lanata, Arenaria capillaris, Agoseris glauca var. cryptogamicstratum. dasycephala, Lupinus latifolius var. subalpinus, Po- a) Lupinus latifolius community.The Lupinus tentilla flabellifolia,Juncus parryi, and Arnica ryd- type,found at lowerelevations (1,750 m to 2,150 m) bergii. in thewestern to centralNorth Cascades (Fig. 3), is Dwarf shrub communitytypes.-In the North Cas- a subalpinecommunity that extendsinto the lower cades eightdwarf shrub community types occur in a alpine zone adjacent to stands of krummholz.It varietyof habitats.This groupcontains five of the occurs most frequentlyon moderate to steep six communitytypes which range across the entire southern,well-drained slopes (Fig. 5). Snowmelt NorthCascadian region. occursin late May to earlyJune. Althoughno data a) Cassiope mertensianacommunity. This is one are available for this communityin the subalpine of the most commoncommunities in the western zone of the centralNorth Cascades, alpine stands NorthCascades, rangingeast to the Slate Peak and appear to be floristicallysimilar to subalpinestands. Glacier Peak areas in the centralpart of the range The Lupinus communityis characterizedby rela- (Fig. 3). Mesic, well-drained,moderately steep to tivelyfew species and a dense cover of mesophytic steep,southern slopes are typicalsites. This com- herbsand sedges. Lupinus latifoliusvar. subalpinus munityis closelyrelated to the Phyllodoceempetri- has a highfrequency and mean cover. Carex spec- formis and Phyllodoce glandulifloratypes (Fig. 2). tabilis, Polygonum bistortoides, Vaccinium delicio- In thesubalpine zone of thewestern North Cascades, sum, Festuca viridula, Erigeron peregrinus var. Cassiope mertensiana and Phyllodoce empetriformis scaposus, and Valeriana sitchensis are major associ- commonlyoccur togetheras codominants(Douglas ates (Table 2). 1972). Comparisonof theheath communities of the

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North Cascades (Table 4) indicates that distinct TABLE 4. Prominence values of alpine and subalpine alpine and subalpine phases may be recognized. phases of the Cassiope mertensiana and Phyllodoce empetriformiscommunities The Cassiope communityhas a high average total plant cover. Cassiope mertensianaoccurs with a high Cassiope frequency and average cover. Luetkea pectinata, merten- Phyllodoce glanduliflora, Antennaria lanata, and PMyl- siana- Cassiope lodoce Phyllodoce Vacciniwm deliciosum are importantassociates; the mer- empetri- empetri- latter is restrictedmainly to the western North Cas- tensiana formis formis cades. In the central part of the region, Phyllodoce Alpine Alpine Subalpinea Species (8) (5) (7) empetriforinisbecomes prominent. Lepraria neglecta is the major cryptogamwith Cetraria islandica and Vascular Plants Polytrichumpiliferum occurring frequently, but with Cassiope inertensiana 408 75 441 low cover. Luetkea b) Phyllodoce empetriformiscommunity. This pectinata 102 16 73 type is found on sites that appear quite similar to Pliyllodoce glanduliflora 83 7 those of the Cassiope type, at least in the western Vaccinium and central Cascades where both are extremelycom- deliciosum 64 68 92 A ntennaria mon. At the eastern extent of its range (Fig. 3), it lanata 43 42 is restricted to slight snowbed depressions in the Phyllodoce lower alpine zone. In this drier region of the Cas- empetriformis 38 307 386 Luzula piperi 12 1 cades, snow melts at approximatelythe same time Carex spectabilis 10 1 (early June to early July) as in the nore exposed Carex nigricans 7 14 2 central and western habitats. Lupinus latifolius 6 1 4 Phyllodoce empetriformishas a mean high cover Juncusparryi 5 5 ---- and frequency. Other prominentspecies are Anten- Empetrum nigrum 4 ---- Erigeron naria lanata (occurring across the entire range), peregrinus 3 9 T Vaccinium deliciosum and Cassiope mertensiana Pl/lox diffusa 2 9 (both restrictedto the westernand central Cascades) Festuca ovina 3 8 Vaccinium and Vaccinium scoparium (found from the central scoparium 1 38 to eastern Cascades). Polytrichum piliferum and Sibbaldia Lepraria neglecta are conspicuous crytogamsin most procumbens 1 5 Carex stands while Dicranum fuscescens is important in phaeocephlala 1 the westernNorth Cascades. A renaria capillaris T 8 c) Phyllodoce glandulifloracommunity. The more Lupinus lepidus T exposed, upper slopes are typical sites of this com- Castilleja munitytype in the westernNorth Cascades. Farther rupicola T east the type occurs in more protected habitats al- Antennaria alpina T T Pedicularis though time of snowmelt is similar (early to late racemosa 14 - June). This type occurs on all aspects and soils Erigeron aureus T ranging from well drained, on smooth slopes, to Poa alpina T more poorly drained on hummocky terrain. Bryophytesand Lichens Floristically, the Phyllodoce com- glanduliflora Lepraria neglecta 87 18 - munityis the richest of the heath types and has a Dicranum high average plant cover. Vaccinium deliciosum fuscescens 37 41 and Luetkea pectinata are importantassociates in the Cetraria islandica 25 1 2 Polytrichum western North Cascades whereas Antennaria lanata piliferum 19 50 and Salix cascadensis are prominentcomponents in Cladonia the eastern stands. Moss and lichen cover is the subsquamosa 17--- 1 highest of all heath types. Important cryptogams Rhacomitrium sp. 41 Cladonia sp. throughoutthe range are Cetraria islandica, Lepraria Total number of species neglecta, and Polytrichumpiliferum. In the eastern Vascular plants 35 35 27 North Cascades the moss, Dicranum scoparium is Bryophytes 9 6 8 conspicuous. Lichens 12 15 11 All plants d) Arctostaphylosuva-ursi community. The Arc- 56 56 46 tostaphyloscommunity is found mainly on southern Subalpine data after Douglas (1972). T (trace) indicates a prominence value <0.5. Number of stands sites where soils are generallypoorly developed, but sampled appears in parentheses.

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Monographs 128 GEORGE W. DOUGLAS AND L. C. BLISS EcologicalVol. 47, No. 2 well drained. It occurs infrequently throughout (early June) than those on exposed sites, drainage is the North Cascades (Fig. 3) in sites where snowmelt good and they become quite dry. occurs from late May to mid-June. This type is Salix cascadensis occurs with relativelyhigh aver- found sporadically in the subalpine zone. age cover and frequency. Throughout the range, Arctostaphylosuva-ursi is the sole dominant, ex- Festuca ovina var. brevifoliaand Carex phaeocephala cept in the western North Cascades where Carex are characteristiccomponents. Erigeron aureus and spectabilis is an important associate. The high Arenaria obtusiloba are importantin the central and cover and dominance of Arctostaphyloslimits other eastern North Cascades whereas in the Glacier Peak species, especially cryptogams,to a low prominence area, Lupinus lepidus var. lobbii is a conspicuous in the type. In the eastern North Cascades, species associate. The prominentcryptogams in most stands richnessis markedlyhigher than in the westernNorth are Polytrichum piliferum, Cetraria islandica, and Cascades. Lepraria neglecta. e) Empetrum nigrum community. This commu- h) Dryas octopetala community. The Dryas type nity type occurs on moderatelysteep, well drained, occurs on slight to moderate slopes of all aspects south to west slopes at lower elevations (1,750 m to from the centralto eastern North Cascades (Fig. 3). 2,100 m) in the western to central North Cascades These sites usually have well-drained,poorly devel- (Figs. 3 and 5). Snowmelt (late May to mid-June) oped soils. Snowmelt is relativelyearly (early to late is similarto that in the heath types. May). Empetrum nigrum has a high average cover and This communityhas one of the lowest total plant frequency. Phyllodoce glanduliflora, although a covers of all types in the region (Table 2). Dryas common associate, occurs with low cover and fre- octopetala var. hookeriana has a moderate mean quency. In the Glacier Peak area, Lupinus lepidus cover and a high frequency. Typical associates, with var. lobbii becomes prominent;Cetraria islandica is low prominence, are Lupinus lepidus var. lobbii, the only prominentand constant cryptogam. Arenaria obtusiloba and Festuca ovina var. brevifolia. f) Salix nivalis community. Communities of this Many cryptogamsoccur frequentlybut all are of low type occur throughoutthe region (Fig. 3) on level importance. to moderatelysteep, exposed, southern slopes. The Dry graminoid communitytypes.-Two grass and soils are extremelyrocky and often show indications five sedge communities are included in the dry of frostaction (i.e., unsortednets, frost-boils). Snow- graminoidcommunity types. These communitiesare melt is relativelyearly, generally occurring between all characterized by a high total plant cover and are mid-May and early June. floristicallyrich. This communityis the only one that shows a sig- a) Danthonia intermediacommunity. Communi- nificant structural change from west to east. In ties of this type cover large expanses in the lower the western and central North Cascades, vascular alpine and subalpine zones of the eastern North plant cover (29 to 43%o,respectively) is much lower Cascades (Fig. 3). The moderate to steep slopes are than in the eastern North Cascades (60 to 121%). well drained and receive moisture from upslope for Species richness is also slightlyhigher in the eastern much of the summer. Snowmelt takes place from North Cascades. mid-May to early June. The Salix nivalis communityhas a moderate aver- Total average plant cover in this type is the highest age plant cover and is relatively rich, floristically. in the alpine zone. Danthonia intermediahas a high Festuca ovina var. brevifolia and Selaginella densa frequency and average cover, and dominates all are constant associates in all stands (Table 2), stands. Many associates, such as Carex scirpoidea whereas Oxytropiscampestris var. gracilis is impor- var. pseudoscirpoidea, Potentilla diversifoliavar. di- tant in the eastern part of the region. The lichens, versifolia,Arenaria capillaris and Arenaria obtusiloba Thamnolia subuliformis,Cornicularia aculeata, Ce- also have high prominence values (Table 2). Com- traria islandica, and Lepraris neglecta are frequent mon cryptogamsare Polytrichumjuniperinum, Poly- throughoutthe range. Polytrichumjuniperinum and trichumpiliferum, Tortula ruralis, Cetraria islandica Desmatodon latifolius are importantmosses in the and Cladonia pyxidata. easternNorth Cascades. b) Calamagrostis purpurascenscommunity. Small g) Salix cascadensis community. In the western stands of this communitytype are frequentat higher North Cascades this community is found on sites elevations (>2,250 m) in the easternNorth Cascades similar to those of the Salix nivalis community. In (Fig. 3). Slopes are moderate to steep, well drained, the eastern part of its range, however, the Salix and often rocky. Snow accumulation is slight with cascadensis type occurs on gentle slopes or level sites snowmelt occurring relativelyearly (April to early of all aspects and often occupies snowbed habitats. May). Although the latter habitats become snow-freelater Calamagrostispurpurascens has a high mean cover

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 129 and frequency and is common only to this type. TABLE 5. Prominencevalues of alpine and subalpine Carex scirpoidea var. pseudoscirpoidea, Arenaria ob- phases of the Carex spectabilis communitya tusiloba, Oxytropis campestrisvar. gracilis, and Po- Alpine Subalpine tentilla diversifolia var. diversifolia are prominent phase phase species (Table 2) in this floristically rich type. Species (4) (5) Cladonia pyxidata, Cetraria Cornicularia aculeata, Vascularplants ericetorum,and Cetraria islandica are the most con- Carex spectabilis 547 782 spicuous of the large number of lichens present. Phlox diffusa 216 Polytrichumjuniperinum is the only constantmoss of Solidago multiradiata 155 Carex breweri 67 importance. Danthonia intermedia 55 c) Carex spectabilis community. This community Cerastium arvense 47 ---- type is restrictedto drier, moderatelysteep to steep, Achillea millefolium 40 Polygonum bistortoides 38 30 upper slopes in the westernNorth Cascades (Fig. 3). Sibbaldia procumbens 38 These southern, well drained habitats are free of Campanula rotundifolia 37 A ntennariaalpina 30 snow relativelyearly (mid-May to early June). This Festuca ovina 20 communitytype also occurs in the subalpine zone Carex phaeocephala 19 (Douglas 1972) but comparison of plant compo- Lupinus lepidus 5 ---- Selaginella densa 4 ---- sition (Table 5) indicates that both an alpine and Luzula spicata 4 ---- subalpine phase should be recognized. Lupinus latifolius 3 42 Total average plant cover is one of the highest of Sedum lanceolatum Carex nigricans 16 all the alpine types in the region. Carex spectabilis Valeriana sitchensis 5 has a high average cover and frequency. Other Epilobium angustifolium 8 Valeri- Viola glabella 7 prominentspecies are Solidago multiradiata, Aster foliaceous T 7 ana sitchensisand Carex breweri (Table 2). Crypto- Bryophytesand lichens gamic cover is high with Cladonia gracilis, Cladina Cladonia gracilis 139 mitis,Cetraria ericetorumand Polytrichumpiliferum Polytrichumpiliferum 123 being major components. Cladina mitis 81 Cetraria ericetorum 54 ---- d) Carex phaeocephala community. This type is Peltigera canina 19 common on moderatelysteep to steep, well drained, Tortula ruralis 18 upper slopes in the westernNorth Cascades. Farther Ceratodon purpureus 14 Cladonia pyxidata 14 east it becomes less frequent and often grades into Heterocladium dimorphum 12 the closely related Carex scirpoidea var. pseudo- Thamnolia subuliformis 12 Dicranum tauricum 10 scirpoidea community.The Carex phaeocephala com- Total number of species munityoccurs mainly on southerlyaspects although Vascular plants 35 30 several stands in the eastern North Cascades were Bryophytes 13 0 found on northwest or northeast aspects. In the Lichens 13 0 All plants 61 30 westernNorth Cascades this major plant community a is the first to become snow free, whereas in the Subalpine data after Douglas (1972). T (tract) indicates a prominencevalue of <0.5. Number of stands eastern part of the region, although snowmelt is sampled appears in parentheses. about the same (May), several other types precede it in the snowmeltsequence. Carex phaeocephala, with a moderatelyhigh mean subuliformis are important throughout the range cover and frequency,is the most prominentspecies (Table 2). in the community. Floristically, this is the richest e) Carex scirpoidea var. pseudoscirpoidea community. In the eastern North Cascades (Fig. 3) this and most variable type in the region. In the western type is frequentlyfound on dry, well-drainedslopes stands Phlox diffusa is a major associate. Lupinus at all elevations and aspects. These sites become lepidus var. lobbii is importantonly in the central snow free between mid-Apriland early May. is com- North Cascades whereas Arenaria obtusiloba Carex scirpoidea var. pseudoscirpoidea has a high mon here as well as farthereast. Carex scirpoidea mean cover and frequency. This species is also one var. pseudoscirpoidea is the most conspicuous asso- of the most common and abundant plants in a num- ciate in the eastern part of the region. Prominent ber of other alpine communitiesin the eastern North lichens, occurring only in the western North Cas- Cascades. Potentilla diversifolia var. diversifolia, cades, are Cladonia gracilis and Cladina mitis. The Carex phaeocephala, Festuca ovina var. brevifolia, moss Polytrichumpiliferum and the lichens Cetraria and Arenaria obtusiloba occur with moderate fre- ericetorum, Cladonia pyxidata, and Thamnolia quency and cover in the type. Prominent crypto-

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions L. C. BLISS Ecological Mono aphs 130 GEORGE W. DOUGLAS AND Vol. 47, No. 2 stripecommunity types.-The levelor gentlysloping summitsof almost every mountainin the North Cascadeshave accumulationsof coarserock detritus. Sincemost of thesesites remain essentially snow free all winter,frost has causedextensive breaking of the bedrock.Other frost-associated phenomena, such as nonvegetatedsorted and unsortedcircles and nets on level surfacesand nonvegetatedunsorted stripes ,~~~~~~~Bo (Washburn1956) or vegetationstripes on slopes,are also commonto thesesummits. Four generalcommunities (herbfields, vegetation stripes,boulderfields, and fellfields)based on amount or arrangementof plantcover or size of rockdetritus may be recognized.If total plant cover is >50%, FIG.6. A Kobresiamyosuroides community at 2,400 theterm herbfield is used. Vegetationstripes, where m on ArnoldPeak, Washington.Salix nivalis,Oxytropis the vegetationis arrangedin long parallelstrips, 1 compestris,and Arenariaobtusiloba are the mostpromi- to 2 m apart,are a secondgroup. These patternsre- nentplants occurring between the Kobresiaclumps. sultfrom downslope soil and rockcreep. If rockor bouldercover comprises at least50% of the ground cover,the termboulderfield is appropriate.If none gams are Tortularuralis, Bryum weigelii, Cetraria of theabove criteria is metthe site is thenclassified as islandica,and Lecidea granulosa(Table 2). fellfield. f) Carex nardinacommunity. This community Thirty-ninestands, containing a totalof 94 vascu- extendsalong the easternflanks of the NorthCas- lar plantand 38 cryptogamspecies, were sampled and cades (Fig. 3). It is restrictedto dryupper slopes analyzed. Beta diversity(Whittaker 1960) was so of thehigher peaks and showsno aspectpreference. greatin thesestands that most of themplotted in a Wintersnow cover is thin,thus snowmelt is relatively single,undecipherable group in thecenter of ordina- early(late Aprilto earlyMay). tions. Separationof the standsinto the above four Carex nardinahas a highfrequency and a moder- classes (i.e., fellfields,herbfields, etc.) or into atelyhigh cover. Commonassociates, although with majorgeographic regions did notimprove ordination low prominencethroughout the community type, are performance.Use of severalcluster techniques (Prit- Festuca ovina var. brevijolia,Arenaria obtusiloba, chardand Anderson1971) illustratedstand relation- and Smelowskiaovalis (Table 2). In thesoutheastern ships more clearly,or at least verifiedthat beta partof thearea (Star Peak) Phloxhendersonii is an diversityis extremelyhigh. The clustertechniques abundantspecies. Importantcryptogams are Tortula indicatedthat no fewerthan 24 setscould be recog- ruralis,Thamnolia subuliformis, and Cornicularia nizedwithin the 39 sampledstands. These sets had aculeata. littleor no correlationwith amount of plantor rock g) Kobresiamyosuroides community. The Kobresia coverand revealedno regionalpattern. myosuroidestype occurs on high (>2,250 m eleva- These communitiesthroughout the North Cas- tion), well-drained,moderately steep to steep,dry cades have manymajor species in common(Table upper slopes (Fig. 6) in the easternpart of the 6). This largenumber of commonspecies and their region (Fig. 3). These exposed habitatsremain relativelylow constancyand varyingabundance re- essentiallysnow free most of the winter. Shallow sultsin a continuousfloristic change within which snow accumulationis foundonly betweenthe tufts no divisionscan be satisfactorilymade, at leastwithin of Kobresiamyosuroides or amonglow earthhum- the communityconcept used in this study. It is mocksin thetype. quite likelythat, with more intensivesampling, re- Kobresia myosuroideshas a high average cover duced plotsize, and the inclusionof all cryptogams, and frequency. Prominentassociates are Carex a "community"pattern would emerge, at least from scirpoideavar. pseudoscirpoidea,Salix nivalis,Oxy- the fellfieldsand boulderfields.These standswould tropiscampestris, Arenaria obtusiloba, Potentilla di- probablybe recognizeableat a microcommunity multiradiata. versifoliavar. diversifolia,and Solidago leveland wouldcorrespond to microhabitats(micro- The totalcryptogam cover is thehighest in theNorth topography)within the fellfields or boulderfields. Cascadian alpine. The mostimportant of the many mostnotable floristic differences taxa are Tortularuralis, Polytrichum juniperinum, In general,the Cladoniapyxidata, Cetraria islandica, Cetraria erice- are due to thosespecies having restricted geographic torum,and Cetrariacucullata. distributionsin the NorthCascades. A numberof Herbfield, fellfield, boulderfield, and vegetation species (e.g., Solidago multiradiata,Oxytropis cam-

~~This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 131~~

~~TABLE 6. Mean prominence values of the major plant species in the herbfield (H), felifield (F), boulderfield (B), and vegetation stripe communities of four regions in the North Cascadesa~~

Northwest North-central Southeast Northeast H F B V H F B V H F H B V Species (3) (6) (3) (3) (2) (1) (3) (3) (9) (1) (1) (3) (1) Phlox diffusa 250 31 1 37 68 25 3 5 Potentilla diversifolia 232 1 8 20 5 10 12 6 25 3 Oxytropiscampestris 147 8 T 37 Solidago multiradiata 141 16 1 10 Carex albonigra 97 8 T 13 1 A chillea millifolium 74 T 1 9 Poa alpina 62 T 7 T Cerastium arvense 52 T T 25 Carex phaeocephala 49 3 5 46 3 9 25 72 10 T Selaginella densa 48 10 7 70 13 1 51 3 3 Festuca ovina 40 2 2 17 23 T 1 5 19 21 8 30 25 Antennaria rosea 17 Trisetumspicatum 16 T 1 3 1 T T T 10 20 5 1 Sedum lanceolatum 13 T 2 12 3 2 18 23 3 4 Silene acaulis 9 T 15 29 1 120 29 8 Draba praealta 8 T Haplopappus lyallii 2 3 26 2 9 1 3 13 3 11 Luzula spicata 4 T 4 13 T 2 9 6 22 9 Phacelia sericea 1 T 7 4 T Draba incerta 1 2 8 1 T Silene parryi T 16 T Lupinus lepidus var. lobbii 4 5 2 1 5 53 310 68 124 Saxifraga bronchialis 4 11 T Antennaria alpina 1 1 9 11 T 2 12 5 28 Smelowskia ovalis 1 1 8 24 1 T Arenaria obtusiloba T 2 6 4 1 28 60 62 48 61 Agropyroncaninum var. latiglume 10 Erigeron compositus var. glabratus 4 1 9 9 20 13 2 Stellaria lonipes T T 5 3 Arenaria capillaris 56 52 53 Arctostaphylosuva-ursi 32 T T Erigeron aureus 16 5 14 T 5 1 Penstemon procerus 2 9 T Vaccinium scoparium 1 5 Draba paysonii T 43 7 2 T T Eriogonum ovalifolium 18 Carex nardina 2 15 67 5 Salix nivalis 13 Phlox hendersonii 70 Carex cf. scopulorum 19 Carex breweri 8- Carex straminiformis 7 Eritrichumnanum 6 Anemone drummondii 6 Douglasia nivalis 6 Arabis lyallii 6 Collomia debilis var. larsenii 36 Carex scirpoidea var. pseudoscirpoidea 18 Poa sandbergii 5 a Onlyspecies with a prominencevalue of 5, or more,in at least one stand are includedin thistable. Numberc standssampled are enclosedin parentheses.T (trace) indicatesa prominencevalue of <0.5.

pestrisvar. gracilis,Achillea millefoliumvar. alpicola, tends north only to the extremesouthern part of the and Cerastium arvense) are often importantin the study area (Star Peak), where it is an important four communitygroupings in the northwesternCas- herbfieldcomponent. Less importantspecies occur- cades, but are absent in these communitieselsewhere ring with the latter and having a similar northen in the range. range limit, are Eritrichum nanum and Douglasia Several species reach theirgeographical distribution nivalis. Farther west, in the Glacier Peak area, limits in the North Cascades. Phlox hendersonilex- Collomia debilis var. larsenii reaches its northern

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions GEORGE DOUGLAS Ecological Monographs 132 W. AND L. C. BLISS Vol. 47, No. 2 limits and is often abundant in fellfields. Rocky tent. The following profile (#10) is typical of Mountain or arctic elements,extending into only the krummholz stands in the western North Cascades: northcentralor northeasternpart of the North Cas- Horizon Description cades are Carex scirpoidea var. pseudoscirpoidea, Potentillanivea, and Potentillauniflora. 01 7 to 1 cm; fresh coniferous (krummholz) Krummholzstands.-The overstorycomposition of litter; krummholz stands changes markedly from west to 02 1 to 0 cm; partially humified forest litter; east in the North Cascades. On the western side of A2 0 to 7 cm; dark reddish gray (10 R 3/1) the range,A bies lasiocarpa is the dominantoverstory sandy loam; weak, medium subangular species. Tsuga mertensiana and Chamaecyparis blocky structure;breaking down to moder- nootkatensis occur infrequently and rare occur- ate fine crumb; veryfriable; abundant fine to rences of A bies amabilis were noted. In the central medium roots; extremelyacidic (pH 4.0); North Cascades, A bies lasiocarpa, Picea engelmannii, abrupt,wavy boundary; and Larix Iyallii are common. The latter is occa- B21 7 to 19 cm; dark reddish brown (2.5 YR sionally found in a prostrate form, but more often 2/4) loam; weak, medium subangular is erect, with flagged tops. Pinus albicaulis also oc- blocky structure,breaking down to moder- curs in the centralNorth Cascades but is less frequent ate, fine crumb; friable; abundant fine to than the previous species. On the eastern side of medium roots; extremelyacidic (pH 4.3); the range, A bies lasiocarpa and Larix lyallii decrease abrupt,smooth boundary; in abundance while Picea engelmanniiand Pinus al- B22 19 to 44 cm; dark brown (7.5 YR 3/2) very bicaulis are common. gravellyloam; weak, very fine crumb struc- The understoryof the 42 krummholzstands sam- ture; friable; few fine roots; very strongly pled during the study showed low cover and con- acidic (pH 4.6); abrupt, irregularboundary; siderable variation in composition (Table 7). The R 44 to 55 or use of ordination and cluster techniques failed to cm more; weathered shale. correlate understorycomposition with either over- Spodzols associated with heath vegetation are storycomposition or geographicalregion. The sparse characterized by thin organic horizons (1 cm), ab- understoryflora appeared to be selected from nearby sent or imperceptiblealbic horizons, and abundant communitiesirrespective of the communitytype. Re- organic matterin the illuvial horizons. Profile #9 is gional separation is not consistentsince speices such typical of heath communities in the western North as Phyllodoce glanduliflora and Festuca ovina var. Cascades. Detailed analyses of this profile by Bock- brevistylamay be importantacross the entire range heim (1972) showed that in the B2 horizon, the (Table 7). Carex concinnoides and Ledum groenlan- ratio of percent pyrophosphate-extractableFe + Al dicum are the only species essentially restrictedto to percentdithionite-extractable Fe + Al exceeds 0.5, krummholzstands in the alpine zone of the North thus placing it withinthe Spodosol Order: Cascades. Vaccinium scoparium is the only species that reaches its maximum prominence beneath Horizon Description krummholzstands. 01 Trace, fresh plant litter (mainly heath species); Soils 02 1 to 0 cm; partially humified herbaceous Morphology.-Alpine soils are relatively poorly plant litter; developed and fall within the Spodosol, Inceptisol, Al 0 to 8 cm; dark reddish brown (5 YR 3/3) and Entisol Orders. All but the latterhave developed fine sandy loam; moderate,fine crumb struc- in parent materials that contain a high pyroclastic ture; very friable; abundant very fine to medium component. These pyroclastic deposits originated roots; extremelyacidic (pH 4.3); clear, smooth boundary; from a number of recent volcanic eruptions within, B21 8 to 16 cm; dark yellowish brown (10 YR and to the south of, the study area (van Ryswyk 3/4) fine sandy loam; moderate,fine crumb 1969; Bockheim 1972). structure;friable; abundant fine to medium The Spodosols of the region occur mainly beneath roots; very stronglyacidic (pH 5.0); grad- krummholz and heath vegetation. The best devel- ual, smooth boundary; opment occurs beneath krummholz, especially in B22 16 to 37 cm; dark yellowishbrown (10 YR the western North Cascades. These profiles have 4/4) gravelly sandy loam, weak to moder- moderatelythick (up to 7 cm) organic layers,moderate, fine crumb structure;friable; plentiful ately well-developed eluvial horizons, and illuvial very fine to fine roots; very stronglyacidic horizons characterized by high organic matter con- (pH 4.9); abrupt, smooth boundary;

~~This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 133~~

~~TABLE 7. Mean prominence values of plant species in four krummholz types in three regions (west, central, and east) of the North Cascades Rangea~~

Krummholz dominants Abies lasiocarpa Larix lyallii Picea engelmannii Pinus albicaulis West Central Central East Central East Central East Species (6) (3) (5) (2) (4) (5) (3) (11) CONIFERS A bies lasiocarpa 950 885 --- 3 Pinus albicaulis 10 1 869 834 Picea engelmannii 7 850 963 1 T Laris lyallii ------740 975 ------VASCULAR PLANTS Phyllodoce glanduliflora 68 18 90 Carex spectabilis 61 ------Vaccinium deliciosum 53 ------Phyllodoce empetriformis 42 6 Leutkea pectinata 40 3 45 ------Cassiope mertensiana 12 103 340 Pedicularis racemosa 10 ------Poa sandbergii 6 5 4 ------Erigeron aureus 6 8 7 1 7 Arenaria capillaris 6 9 3 2 1 Haplopappus lyallii 5 12 4 1 4 7 6 Phlox hendersonii 3 ---- 4 ---- 7 ---- Anenome drummondii var. drummondii 3-1 10 7 Penstemon procerus 58 T Poa nervosa 19 4 2 1 Phlox diffusa 11 2 Agoseris glauca 5 T Empetrum nigrum 8 Arnica latifolia var. gracilis 5 ------Festuca ovina var. brevistyla 5 9 1 6 1 9 Hieracium gracile 2 9 8 1 Luzula wahlenbergii 1 101 Veronica wormsjoldii 1 4 6 Vacciniumnscoparium 158 24 100 2 26 Penstemon davidsonii var. davidsonii 11 24 1 4 4 35 Arenaria obtusiloba 33 1 3 1 Dryas octapetala 4 24 14 Juniperuscommunis 2 2 199 42 Carex phaeocephala 2 1 5 1 2 Ledum groenlandicum 12 Carex rossii 8 Carex concinnoides 1 10 a Only those species with a prominence value of 5, or more, in at least one type are included in this table.

C 37 to 66 cm or more; yellowish brown (10 have one or more ash layers present. Buried A YR 5/4) very gravellysandy loam; massive; horizons may also occur below these ash layers. friable; few to plentiful fine roots; very Profile #28 illustrates the characteristicsof these strongly acidic (pH 4.8). soils in a Carex nigricans communityin the central Most of the communities in the North Cascades North Cascades: have soils typicalof the Inceptisol Order. The Incep- tisols are rather weakly developed, lacking signifi- Horizon Description cant illuviation, eluviation, or extreme weathering. 01 Trace; fresh sedge (Carex nigricans) litter; These soils have moderately thick (4 to 10 cm) 02 2 to 0 cm; partially humified sedge litter; turfyA horizons and relatively high accumulations of organic matterin the illuvial horizons. Communi- Al 0 to 5 cm; very dark grayishbrown (10 YR ties associated with the Inceptisols range from the 3/2) loam; weak, fine crumb structure; poorly drained snowbed typesto the well-draineddry friable; abundant very fine roots; very grass and drysedge types. strongly acidic (pH 4.7); abrupt, wavy Inceptisols in poorly drained depressions often boundary;

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions 134 GEORGE W. DOUGLAS AND Ecological L. C. BLISS Vol.Monographs 47. No. 2 B21 5 to 11 cm; dark brown (10 YR 3/3) sandy the Entisols. These soils are associated with either loam; weak, fine crumb structure; friable; unstable snowbed sites or the high windsweptridges plentifulvery fine roots; stronglyacidic (pH and plateaus. The latter areas usually support boul- 5.2); gradual, smooth boundary; derfieldand fellfieldcommunities although several of B22 11 to 21 cm; dark brown (10 YR 3/3) the shrub communitytypes may also occur on these sandy loam; weak, fine crumb structure; sites. The Entisols generallyhave only thin surficial friable; plentiful very fine roots; strongly A horizons beneath the sparse plant cover. Profile acidic (pH 5.5); abrupt,wavy boundary; #7 is typicalof the Entisols occurringin the boulder- Cl 21 to 24 cm; grayish brown (10 YR 5/2); fields and fellfieldsof the westernNorth Cascades. sandy loam; weak, fine crumb structure;few Horizon Description very fine roots; stronglyacidic (pH 5.5); abrupt,wavy boundary; Cl 0 to 2 cm; very dark gray (5 Y 3/1) C2 24 to 28 cm; dark yellowishbrown (10 YR gravelly loam; structureless; friable; no 4/4) sandy clay loam; weak, fine crumb roots; very stronglyacidic (pH 4.7); grad- structure; few very fine roots; strongly ual, smooth boundary; acidic (pH 5.5); abrupt,wavy boundary; C2 2 to 18 cm; very dark grayishbrown (2.5 Y C3 28 to 31 cm; brown (10 YR 4/3) sandy 3/2) gravellysandy loam; structureless;fri- loam, weak, fine crumb structure;few very able; no roots; very strongly acidic (pH fine roots; stronglyacidic (pH 5.5); abrupt, 4.6); abrupt,wavy boundary; wavy boundary; R 18 cm or more; weathered shale. C4 31 to 34 cm; dark brown (10 YR 3/3) Physical and chemical properties.-Physical and sandy loam; weak, fine crumb structure;few chemical propertiesof soil profiles were determined very fine roots; stronglyacidic (pH 5.4); in a number of the major plant communitiesacross abrupt,wavy boundary; the North Cascades Range. Soil pH varies markedly C5 34 to 60 cm or more; dark yellowishbrown both within and between soil profiles,but generally (10 YR 3/4) sandy loam; weak, fine crumb decreases with depth. The most acidic soils (pH 3.8 structure;few veryfine roots; stronglyacidic to 5.0) are those associated with krummholz and (pH 5.2). heath vegetation in the western North Cascades. Well-drained sites have A-B-C profiles typical of Inceptisols are also highly acidic (pH 3.9 to 5.1) in 4.7 to the Inceptisols. The following profile (#27) oc- the westernpart of the region. Less acidic (pH in habitats curred beneath a Kobresia myosuroides community 5.9) soils occur snowbed and fellfield 5.2 to in the easternNorth Cascades: throughoutthe range. The least acidic (pH 6.0) soils are those associated with Dryas octopetala Horizon Description and dry graminoidcommunities in the eastern mountains. 01 3 to 2 cm; freshsedge litter; All soils become coarser texturedwith depth. Total 02 2 to 0 cm; partially humified sedge litter; sand generallyincreases with depth. Maximum clay Al 0 to 9 cm; black (10 YR 2/1) sandy loam; concentrationsusually occur in the upper B horizon. weak, fine crumb structure;friable; abun- Sand plus silt to clay ratios are relativelyhigh in all dant, very fine to fine roots; stronglyacidic soils, possibly a reflectionof the large amounts of (pH 5.3); gradual, wavy boundary; pyroclasticmaterials present. B21 9 to 19 cm; very dark brown (10 YR 2/2) Organic matter is highest in the surface mineral sandy loam; weak, fine crumb structure;fri- horizons (except A2 horizons) and decreases with able; plentiful, very fine roots; medium depth in the western North Cascades. Farther east, acidic (pH 5.7); abrupt, wavy boundary. organic matterlevels are lower and maximumorganic B22 19 to 24 cm; dark yellowish brown (10 YR matter concentrationoften occurs in the upper B2 3/4) sandy loam; weak, very fine crumb horizons. structure;friable; few very fine roots; me- Total exchange capacity levels are positivelycor- dium acidic (pH 5.7); abrupt, irregular related with the organic mattertrends. Exchangeable boundary; cations in soil profiles of the region generally de- C 24 to 60 cm or more; brown (10 YR 4/3) crease with depth. Sodium occurs only in small gravellysandy loam; weak, fine crumb struc- quantities,except in the A2 horizons of krummholz ture; friable; few very fine roots; medium stands and A 1 horizons of Kobresia myosuroides acidic (pH 5.8). communities. Calcium, magnesium, and potassium The most poorly developed soils in the region are levels are low, but are comparable to those deter-

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 135 mined on similar parent materials in other alpine Precipitation.-Long-range climatic data for the areas (Klikoff 1965; Nimlos and McConnell 1965; few permanent weather stations show a decreasing Bliss 1966; Johnson 1970; Knapik et al. 1973). In summer rainfall pattern from west to east (U.S. the eastern North Cascades (British Columbia), Weather Bureau, no dates). This pattern may be van Ryswyk (1969) found much higher sodium broken during individual summers, such as in 1972 and slightly higher calcium levels in alpine soils. when precipitation(17 cm) on east Chopaka Moun- Available phosphorus generally decreases with tain exceeded that (8 cm) on west Grouse Ridge depth in contrastto some alpine soils in which phos- (Table 8). Length of the intervalsbetween rainfall phorus increases with depth (Nimlos and McConnell fluctuatedgreatly. The summer of 1970 was char- 1965). Kuramoto and Bliss (1970) also found that acterized by frequent storms while lengthy periods phosphorus decreased with depth in the Olympic without precipitation occurred during the summers Mountains of Washington. Potassium levels also de- of 1971 and 1972. Winter precipitation and snow crease with depth and have their highest levels depth data are not available. (162.5 to 217.5 meq/100 g) in Carex nigricansand Atmospheric moisture.-Average vapor-pressure Antennaria lanata snowbed communities. Available deficits (VPD) are relativelylow across the entire nitrogenlevels are low throughoutthe region. Nimlos North Cascades Range (Table 8). Mean daily VPD et al. (1965) also reportedlow nitratenitrogen levels at Grouse Ridge during each of the three summers in alpine soils in Montana, although "total" nitrogen was 0.11 cm Hg while farthereast at Slate Peak was high. In the eastern North Cascades, van and Chopaka Mountain mean daily VPD was 0.14 Ryswyk(1969) reportedlow nitrogenvalues whereas (1971) and 0.13 cm Hg (1972), respectively.Maxi- in the western North Cascades, Bockheim (1972) mum VPD at Grouse Ridge during the study period reportedhigher nitrogen values. was 0.58 cm Hg, 0.90 and 0.88 cm Hg at Slate Peak, and 1.15 cm Hg at Chopaka Mountain. In Microclimate general, the data indicate that evaporation is highest in the eastern Cascades and lowest in the western Solar radiation.-Summer solar radiation fluctu- Cascades. ated markedly from year to year due to varying Wind.-Wind speeds are lower in the western amounts of cloud cover. In general,average radiation North Cascades and slightlyhigher in the central increased from west to east (Table 8) due to the and eastern North Cascades (Table 8). Maximum increased cloudiness in the westernNorth Cascades. average velocity (2.4 m/s) at Grouse Ridge occurred The highestrecorded value 34.22 MJ/(m2 * day) [= during a 24-h stormyperiod in early August 1971. 818 ly/day] occurred several times during 1972 on Wind speeds were highest (5.3 m/s over 7 days) Chopaka Mountain. In the central North Cascades at Sahale Mountain. This is likely due to its ridge- (Slate Peak) maximum values of 31.59 to 31.88 top location at the headwaters of two large drainage MJ/(m2 * day) [= 755 to 762 ly] occurred on several systems. The average maximum weekly velocities at occasions. At Grouse Ridge maxima were typically Slate Peak and Chopaka Mountain were 3.0 and 4.5 between 27.62 and 28.45 MJ/(m2 * day) [= 660 to m/s respectively,during 1972. 680 ly/day] although 33.05 MJ/(m2 * day) [= 790 ly/day]was recorded once. Environmentalgradient Temperature.-The long-termsummer mean, minimum, and maximum temperature patterns show Vegetation.-An alpine slope at 1,790-m elevation higher temperatures in the eastern Cascades and on Grouse Ridge, Mt. Baker, was selected for an lower temperaturesin the western Cascades (U.S. intensive plant distribution-environmentalgradient Weather Bureau, no dates). During 1970, when study. This slope was chosen because of its relative stormfrequency was high,temperature varied greatly. ease of access (3-km hike) and the general repre- Periods of continuous, relativelyhigh temperatures sentativenessof its plant cover. The changes in spe- were common during 1971 and 1972. Mean daily cies composition and structurealong this continuum maxima of 15.8 to 17.51C, mean daily minima are, for the most part, gradual (Figs. 7 and 8), as is of 4.8 to 6.20C, and mean daily temperaturesof the angle of the slope. 10.2 to 11.80C occurred on Grouse Ridge (Table 8). At the ridge top, where the slope angle is slight The Slate Peak station had even highertemperatures (<11%) and exposed to strongerwinds, the vege- (19.8 to 25.20C, 6.4 to 11.50C, 12.6 to 17.90C re- tation occurs in patches (total cover 2 to 60%, x spectively) during this period. On less than 5% of = 18%) among the frost-shatteredrocks. Phlox dif- the nights (June-August) temperatures <00C oc- fusa, Solidago multiradiata, Silene parryi and the curred,although lows of 50 to 10'C were most com- lichen Cladina mitis are the most prominentplants mon. in thisfellfield habitat.

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions 136 GEORGE W. DOUGLAS AND L. C. BLISS EcologicalMonographs Vol. 47, No. 2 TABLE 8. Environmentaldata for five weatherstations in the North Cascades Range

Solar radi- Temperature ation ('C) 15 cm Pre- Stationa (lang- VPD cipi- and ley/ x Wind (cm tation elevation day) daily x daily (m/s) Hg) (cm) Date (m) 15 cm min daily max 60 cm 15 cm 60-cm 1970 6/13-7/5b Grouse 515 6.8 12.2 16.9 1.9 .09 2.57 7/6-8/2 1785 484 6.1 11.0 15.9 1.4 .12 8.39 8/3-8/29" 475 6.7 11.2 15.8 1.4 .12 1.65 1971 6/30-8/1 Grouse 567 4.8 10.3 15.8 1.7 .12 2.67 8/2-8/30" 1785 528 6.2 11.3 17.1 2.0 .10 2.20 1972 6/30-7/30c Grouse 5.8 11.8 17.5 2.0 .11 8.07 8/7-8/22 1785 5.5 10.2 16.4 .11 1971 7/21-7/29 Slate 11.5 17.9 25.2 2.8 .17 0.00 7/30-9/3f 2135 641 7.2 13.1 19.8 2.9 .14 3.31 1972 7/23-8/159 Slate 734 6.4 12.6 20.6 2.3 3.07 2135 1970 8/6-8/30 Sourdough 2.8 9.4 18.0 .10 0.54 8/31-9/13 1970 5.25 1970 7/4-7/30 Sahale 4.5 8.76 7/31-8/30 2045 4.2 2.27 1972 6/6-6/25' Chopaka 773 0.1 2.7 6.3 .03 11.05 6/26-7/16 2400 1.0 5.7 11.1 3.7 .08 1.06 7/17-8/16' 573 6.5 14.0 23.5 3.2 .24 5.27 Weatherstation locations appear on Fig. 1. Temperature,average vapor pressuredeficit, and solar radiationbased on 18, 18, and 13 days data, respectively. Temperatureand VPD based on 19 days data. Temperature,VPD, and solar radiationbased on 24, 21, and 20 days data, respectively. Temperatureand VPD based on 22 days data. f Solar radiationbased on 18 daysdata. 9 VPD and solar radiationbased on 13 and 9 days data, respectively. Solar radiationbased on 7 daysdata. VPD and solar radiationbased on 20 and 10 days data, respectively. i To convertlangleys to joules per square meter,multiply by 4.184 X 10'.

Farther downslope (11 to 13 m), the slope angle nence. Claytonia lanceolata, although dormant at increases to 27% and the vegetation is essentially the time of the vegetationsurvey, had a mean cover continuous. Total cover is higher (85 to 112%, x of 29% and a frequencyof 100% at the base of the = 95%) with Phlox diffusa, Solidago multiradiata, slope duringearly July. Carex phaeocephala, Carex spectabilis, and Polygo- Soils.-Soils of the environmentalgradient vary num bistortoidesdominating. Cladina mitis,Cetraria markedly from the poorly developed Entisols in the ericetorum,Cladonia gracilis, and Polytrichumpilif fellfieldto the relativelybetter developed Inceptisols erum are importantcryptogams in the understory. found on the remainderof the slope (Fig. 7). Fell- Total cover continuesto increase downslope reach- field soils show no profile development except for ing a maximum of 156 to 217%, X = 172%, at the thin, surficial A horizons beneath the scattered base of the slope (nearly level). From 41 m down- clumps of vegetation. slope, Carex spectabilis,Polygonum bistortoides,Lu- The major portion of the gradientis characterized pinus latifoliusvar. subalpinus, and Potentilla flabel- by Inceptisols beneath continuous vegetation. The lifolia become the major dominants, while other horizons, except for increased thickness downslope, vascular plants and cryptogamsare of low promi- show only slightmorphological variation.

~~This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 137~~

~~0 F 1 50 W~~

~~MNII X0 f wSD IJ eEXW~~

~~w~~~~~~~~~~~~~~~~~~~~~~~~ -J~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~_100SOIL PROFILE 20~~

~~0. SOIL PROFILE20 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ SOLPRFIE23-~~

~~ALL 0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1786T 18.4 85016414016.>6.7. 0~~

~~TOTAL COVBER (%) PROEILEE~~

~~VASCULAR SPECIES 16.8 62.0 109.4 89.5 158.5 166.5 171.5 BRYOPHYTES .1 3.5 14.0 2.0 - - - LICHENS 1.5 19.5 63.0 62.5 4.0 - - ALL PLANTS 18.4 85.0 186.4 154.0 162.5 166.5 171.5~~

~~TOTAL NUMBEROF SPECIES VASCULARSPECIES 9 15 16 13 9 5 4 BRYOPHYTES 2 5 5 1 1 - - LICHENS 3 9 6 3 3 - - ALL PLANTS 14 29 27 17 13 5 4~~

~~0 10 20 30 40 50 60 70 DISTANCE - M~~

~~FIG. 7. Vegetation-soilrelationships along an environmentalgradient on Grouse Ridge,Mt. Baker,Washington.~~

Physical and chemical propertieswere determined and -10 and -30 cm at 61 m downslope) were for seven proflies along the environmentalgradient. monitoredalong this gradient. All properties were comparable to those found in Seasonal temperatureprofiles along the transect similar communitiesin the western North Cascades. vary considerably from the top of the ridge to the Organic matter, total exchange capacity, exchange- base of the slope although all stations have the same able cations, available phosphorus and potassium increasing seasonal pattern (Fig. 10). Fellfield air were highest,but pH was lowest, at the base of the (+5 and +15 cm) temperaturesat the top of the slope. Sand plus silt to clay ratios are relativelyhigh transect,in contrastto those on the remainderof the throughoutthe gradient (Douglas 1973). slope, were usually lower than temperaturesat sub- Microenvironment.-The general environmental surface depths. Highs of near 350C were reached data for Grouse Ridge were presented in a previous several times during 1971 and 1972 at -2 cm. These section (Table 8). A more detailed account of the high subsurface temperaturesare due mainly to a microenvironmentappears in Fig. 9. Patterns of higher rock content,lower plant cover, and the low temperature,VPD, solar radiation, and precipitation heat capacity of the moisture-poorsubstratum. Tem- fluctuate markedly, both during and between sum- peratures beneath vegetation were generally 2 to mers, in this maritimetype alpine region. YC3 lower than for adjacent nonvegetated sites. Air temperatures(+5 and +15 cm at 4, 19, and Average temperaturesat -10 cm in the fellfieldwere 36 m downslope and +10 and +20 cm at 61 m down- 70 to 80C lower than that at -2 cm. slope), soil profile temperatures(-2 and -10 cm on Subsurface temperaturesalong the remainder of both vegetated and nonvegetatedsites at 4 m down- the transect showed sharp vertical gradients over slope and -10, -20, and -30 cm at 19, 36, and 61 m relatively short distances. The steepest gradients downslope), and soil moisutre regimes (-5 cm on were between the surface and -10 cm level. These both vegetated and nonvegetatedsites at 4 m down- profile temperature gradients remained relatively slope, -10 and -20 cm at 19 and 36 m downslope, constant throughoutthe summer except during pe-

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions GEORGE W. DOUGLAS AND L. C. Ecological Monographs 138 BLISS Vol. 47, No. 2 riods of rapidly decreasing air temperatures. Tem- (Kuramoto and Bliss 1970; Peterson 1971) and the peratures at -10 to -30 cm decreased slightly(20 to Colorado Rockies (Ehleringer and Miller 1975). 40C) with distance downslope, reflectingthe insula- A thirdset of readingswas obtained on August 30, tion affordedby increased plant cover. 7 days after a heavy rain (2.2 cm). Most plants Soil moisture along the environmental gradient were dispersing seeds at this time. Leaf i, except closely paralleled the summer precipitationpattern. for Vaccinium caespitosum, were slightlyhigher for This was especially evident in 1970 when frequency species near the top of the slope. The lowest leaf i of summer rainfall was high (Fig. 9), and soil for species at the base of the slope were reached at moisture regimes fluctuated accordingly. Soil mois- this time. These leaf i were still much higher than ture declined steadily throughout the summers of those attained by the same species upslope. Readings 1971 and 1972 due to low precipitation. The use showed high diurnal amplitudeswith species increas- of the -15-bar soil water potentialto estimateperma- ing by as much as 11 bars at 2400 h from their nent wilting percentage is somewhat questionable afternoon lows. Therefore, the plants may spend (Slatyer 1967). However, it gives an indication of part of the day at a lower leaf f and still be photo- increasing water stress. Soil moisture usually re- syntheticallyactive in the morning. Kuramoto and mained well above -15 bars until mid-August,except Bliss (1970), working in the Olympic Mountains, in the fellfieldwhere levels often fell below -15 bars Washington, found that at a soil f of -15 bars, by mid-July. Soil moisture stress increased slightly, Festuca idahoensis, Lupinus latifoliusvar. subalpinus with distance, down the continuouslyvegetated por- and Eriophyllumlanatum still maintain a photosyn- tion of the transectduring drought periods, probably theticrate 40% that at -0.3 bars in plants from a due to the greatertranspiration losses associated with subalpine meadow. increased plant cover. Phenology.-Plant phenologycan often be helpful Plant water relations.-Leaf water potentials (i) in describingmicroenvironmental differences between of eight plant species along the environmentalgradi- various habitats (Bliss 1962) as well as along en- ent, and two other nearby species, were measured vironmentalgradients. During the summersof 1971 duringand aftera droughtperiod in 1971 (Table 9). and 1972, 32 species were observed at 10-m intervals The readings for each species at each site were rela- along the transect. tively consistent with standard deviations varying Phenological phases varied considerably among between 0.3 and 1.5 bars. The first measurements species along the gradient (Fig. 11). Length of a were taken on July 20 after a 1-wk period without given phenological phase was relatively consistent precipitation. The lowest leaf i (-14 to -15 bars) within species, regardless of the year or position on were obtained 20 m downslope in an area that had the slope. been snow-free for 4 to 5 wk. Readings in the Snowmelt took place at about the same time in fellfieldand at 40 to 43 m downslope were also rela- both 1971 and 1972. The upper part of the slope tively low (-12 to -14 bars). Higher leaf i of -5 was free of snow by 18 June and at the base by 28 bars was recorded at the base of the slope, an area June. The much higher temperaturesin late June that had been snow-freefor only 3 wk. and early July during 1972, however, resulted in Measurements taken 24 days later showed only more vigorous vegetative growth and an earlier slightlylower leaf i althoughsoil i had markedlyde- flowering for most species. This was especially creased to -14 to -17 bars. The lowest leaf i for notable in the upper part of the gradient. Silene most species was recorded at this time. Lupinus parryi,in the fellfield,and Potentilla flabellifolia,at latifolius (at 21 m downslope) and Phyllodoce em- the base of the transect, were exceptions to this petriformis(adjacent to the transect at 25 m pattern. downslope) reached lows of -27 and -22 bars, re- At any given point on the environmentalgradient, spectively. The Lupinus plants were wilted at this most of the species have similar floweringphases, an time and died back several days later. The Phyl- indication that local microenvironmentsgovern phe- lodoce empetriformisplants appeared normal. Other nological development (Bliss 1956). The most nota- species reached lows of -12 to -18 bars. At this ble exceptions to this were the late development of time soil i was -14 bars at 19 m downslope and Aster foliaceus and the early development of Clay- -14 to -17 bars at 36 m downslope. Similar low leaf tonia lanceolata. In general, most species flowered [ have been reported from the Olympic Mountains 14 to 24 days after initation of growth. They re-

~~FIG. 8. Distributionand abundanceof majorplant species along an environmentalgradient on Grouse Ridge,Mt. Baker,Washington.~~

~~This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 139~~

~~600l Cladonia gracilis - ::11 Cladina mitis ...... Soo500 Polytrichum piliferum : . Cetraria ericetorum *---~~

~~400~~

~~300 200 oLL .~~~~~~~s 100 01 0~~

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~~z E 900 o Carex spectabilis = 800[ Polygonumbistortoides Lupinus latifolius so Potentilla flabellifolia ._._. 700~~

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~~0 10 20 30 40 50 60 DISTANCE DOWNSLOPE - M?~~

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions 140 GEORGE W. DOUGLAS AND L. C. BLISS Ecological Monographs Vol. 47, No. 2 40 1970 .-a 1971 Ai 30 1972- I- WoJ20La v -% 2"'-

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This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 141 mained in flower for 8 to 20 days before entering where slow downslope creep takes place. Prominent a 10- to 24-day fruitingstage prior to seed dispersal. plants in these habitats are Phlox diffusa,Potentilla diversifolia var. diversifolia, Solidago multiradiata, DISCUSSION Oxytropiscampestris var. gracilis, and Carex albonigra. Community pattern Changes in macroclimate in an easterly direction Distribution of alpine plant communities in the resultin gradual changes in the plant communitypat- North Cascades is in response to complex environ- tern. Lower snow accumulation, slightly earlier mental factors and environmentalgradients. When snowmelt,and somewhat drier and warmer summers environmentalgradients are steep, abrupt changes in in the centralNorth Cascades resultin the absence of species compositionoccur, creatinga mosiac of plant some communities and the appearance of others. communitieson the landscape. If these gradientsare Late-meltingsnowbanks are still occupied by Carex gentle, more gradual changes create a continuum. nigricans but snow accumulation sites that become In the North Cascades, the mosiac pattern is more snow-freeearlier are dominatedby Antennarialanata common, especially in the western and central por- or Carex breweri (Fig. 2). Antennaria lanata com- tions of the range. This is due to the complex topog- munitiesoften occur in close proximityto the Carex raphy and greatersnowfall which results in variable nigricanstype, but the formerare betterdrained sites snow depths and snowmelt times and a broad range and become drierin late summcc. The segregationof of summer soil moisture regimes. These environ- communitieswithin an alpine snowbank site was also mental factors are also of prime importance in the noted in the Presidential Range of New Hampshire eastern North Cascades, but to a lesser extent. In (Bliss 1963), the Rocky Mountains (Billings and the eastern mountains the more gentle topography, Bliss 1959; Johnson and Billings 1962) and the lower snowfall,and more rapid snowmeltresult in a Olympic Mountains of Washington (Bliss 1969). In gradual shift in community pattern. steep, unstable snow-accumulationareas in the cen- The importanceof the time of snowmeltis demon- tral North Cascades, the Eriogonum pyrolaefolium- strated by the two-dimensionalordinations (Fig. 2) Luzula piperi communityreplaces the Saxifraga tol- of the major communitytypes. The date of snow- miei-Luzula pipericommunity. melt also determines the summer soil moisture The same heath communities found to the west regime, at least for the earlier, and probably the occupy similar habitats in the central region. Com- most importantpart of the growing season. munities dominated by Salix cascadensis or Salix In the western mountains, a distinct mosaic ap- nivalis also occupy drier exposed slopes. The driest pears repeatedlyon the landscape. Snow depth and of these exposed slopes, and some of the ridgetops, snowmelt time varies considerably. In snowbank are characterized by extensive mats of Dryas octo- sites, communitiesare dominated by Carex nigricans petala. unless the soils are unstable, in which case the Sax- Warm, moist, southern lower slopes are occu- ifraga tolmiei-Luzulapiperi communityoccurs. pied by the Lupinus latifolius community but the On better drained habitats where snowmelt is closely related Carex spectabilis community is ap- earlier, the heath communities,dominated by either parently replaced on drier central region sites by Cassiope mertensiana, Phyllodoce empetriformis, Festuca viridula. Carex phaeocephala again domi- Phyllodoce glanduliflora,Arctostaphylos uva-ursi, or nates sites that are snow-free earlier, but on the Empetrum nigrum,are common. The latter is most most exposed upper slopes Carex nardina becomes frequentlyfound on exposed or northerlyaspects. the most prominentspecies. Exposed sites with slightly earlier snowmelt times The herbfields,fellfields, boulderfields, and vege- are dominated by Salix cascadensis or Salix nivalis. tationstripes in thisregion are also extremelyvariable Communities on warm, moist, lower southerly in plant and rock cover and species composition. Im- slopes are dominated by the Lupinus latifoliustype. portant plants are Selaginella densa, Phlox diffusa, The closely related Carex spectabilis communityoc- Carex phaeocephala, and A renaria capillaris, and curs on similar, but slightlydrier and often higher farthersouth, Phlox hendersoniiand Lupinus lepidus slopes. Where the earliest snowmeltoccurs (Fig. 3), var. lobbii. the sites become relativelydry by mid-summerand The dry,warm summersand lower wintersnowfall are dominated by Carex phaeocephala. in the eastern North Cascades provide community On ridgetops,which have little snow cover during patternsthat are in marked contrast to those to the most of the winter,herbfields, fellfields, boulderfields, west. Although mosiac patterns are still common, and vegetation stripes are typical. These sites may many extensive slopes show gradual changes in spe- be occupied by a varietyof species, eitherin clumps, cies composition in response to more gradual en- where the surface is stable, or in vegetation stripes vironmental gradients. Communities which span

~~This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions 142 GEORGE W. DOUGLAS AND L. C. BLISS EcologicalMonographs~~

~~40 DISTANCE DOWNSLOPE - 4 M~~

~~30 -10~~

~~.15~~

~~30 DISTANCE DOWNSLOPE - 19 M~~

~~20 .15 u M~~~~2 0 10 -10 -20 -30 W 0~~

~~W.3 DISTANCE DOWNSLOPE 36 M~~

~~CI- 33 20 .5 .15 - 2~~

~~10 -10 -20 -30~~

~~30 DISTANCE DOWNSLOPE - 61 M~~

~~.10 20 .20 g * '' -2~~

~~10 -1 -20 -30~~

~~15 30 15 JULY AUGUST~~

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TABLE 9. Seasonal leaf waterpotential (bars) of 10 plant speciesalong an environmentalgradient on Grouse Ridge, Mt. Baker,Washington during 1971. Data are means of at leastthree readings taken between 1300 and 1500 h; ex- ceptthose in parentheseswhich were takenat 2400 h

Downslope Date distance Species (m) July20 August13 August30 Lupinus lepidus 1 -13.8 Solidago multiradiata 5 -15.2 Solidago multiradiata 7 -11.9 -13.1 Polygonum bistortoides 7 -17.9 Polygonum bistortoides 9 -13.8 -15.5 Solidago multiradiala 19 -15.0 -15.9 -15.1 Polygonum bistortoides 19 -15.0 -17.9 -15.2 (-4.5) Lupinus latifolius 19 -27.4 Vaccinium caespitosum 21 -13.8 -14.1 -17.0 (-7.9) Erigeron peregrinus 21 -17.2 Polygonum bistortoides 36 -11.8 -12.4 Lupinus latifolius 36 -12.0 -12.9 Aster foliaceus 43 -11.0 (-5.5) Polygonum bistortoides 61 -5.1 -5.2 -5.8 (-2.1) Lupinus latifolius 61 -5.0 -5.5 Lupinus latifolius 63 -7.6 -9.2 (-3.4) Castilleja miniata Not on transect -16.2 Vaccinium deliciosum Not on transect -10.2 -12.4 -8.3 (-6.5) Phyllodoce empetriformis Not on transect -15.6 -22.1 -21.9

the entire range may change with respect to com- The driestof the major alpine communitiesoccurs position and habitat (e.g., Phyllodoce empetriformis, on the higher slopes and summits. These are domi- P. glanduliflora,and Salix cascadensis) or structure nated by Carex nardina, Calamagrostis purpurascens, (e.g., Salix nivalis). or Kobresia myosuroides. The topographicalposition Numerous snowbank communities occur in this of the Kobresia myosuroides community suggests region. Carex nigricansis essentiallyrestricted to the that these sites are essentially free of snow with subalpine zone with Antennaria lanata or Carex ephemeral microdriftsoccurring during the winter, breweri dominatingthe alpine sites where snow ac- such as Bell (1973) reported for this type in the cumulation is greatest (Fig. 2). Snowbed sites that Rocky Mountains of Colorado. The Calamagrostis open slightlyearlier are occupied by Phyllodoce em- purpurascensstands often occur in rocky sites within petriformis,Phyllodoce glanduliflora, or Salix cas- larger Kobresia communities. These rocky sites may cadensis. At higher elevations, level areas or de- provide slightlybetter protection during the winter. pressions which receive moisture for much of the The herbfields,boulderfields, and vegetationstripes summer from upslope, are dominated by Carex which occupy the driest, snow-free ridgetops, vary capitata. considerably in composition. Lupinus lepidus var. On well-drainedhabitats where snowmeltis earlier, lobbii, Arenaria obtusiloba, and Festuca ovina var. communities may be dominated by Carex phaeo- brevifoliaare prominentspecies. cephala, A rctostaphylosuva-ursi, Salix cascadensis, The overstorycomposition of krummholz stands Salix nivalis, or Dryas octopetala, with the lattertwo changes markedlyacross the North Cascades. In the occupying the driestsites. At lower elevations in the westernpart of the range, Abies lasiocarpa predomi- alpine and subalpine zones of the eastern region, nates. Abies lasiocarpa, along withPicea engelmannii where soil moisturelevels are greater,broad expanses and Larix lyallii,is common in the centralNorth Cas- are dominated by Danthonia intermedia. Upslope, cades. Farther east Picea engelmannii and Pinus thiscommunity often grades into the Carex scirpoidea albicaulis dominate the krummholzstands. Regional var. pseudoscirpoidea type, another extensive com- separation on the basis of understorycomposition munity. is inconsistentdue to considerable variation in com-

FIG. 10. Seasonal variationsin soil and air temperatureprofiles at variousheights (cm) and depths(cm) along an environmentalgradient on Grouse Ridge, Mt. Baker,Washington during 1971. The dottedline representsthe daily maximumair temperatureat an adjacentweather station. Temperature profile data are for readingstaken between 1300 and 1500 h. Soil temperaturesin the fellfield(4 m downslope) were monitoredon both nonvegetated(NV) and vegetated(V) sites.

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions 144 GEORGE W. DOUGLAS AND L. C. BLISS EcologicalMonographs Vol. 47, No. 2 Polygonum bistortoides Carex spectabilis i f I S Oix 1 __ ~~~~f I X lv S- I

~~11_ I S V IS~~

~~21 _ 21~~

~~v 31 V I S 31 Vf V I S v 41 VI V S 41~~

~~51 -1_ Is 51 _ V~~~ 61 V I S 61 V f~~

~~Lupinus latifolius Phlox diffusa 11 I S s I _ 1 _ V ~~~~tIS~~~~f I s x V f I s IX 21 = V V - I S~~

~~31 v I S 21 V f I S V _ S M&V f I S f 41 _ S 31 vI~~

~~V S 51 I 41 V_ I S V f I S 61 _ Solidago multiradiata~~

~~Carex phaeocephala V I S II 1 ______I ~~~~~~~~~~~fI S f I S I x V1__ f I S 21 _~~

~~21 = _ Sibbaldia procumbens Silene parryi _E I s o1 V f I S IX li v ~~~~~f f I S V1 S V f 11 I S 21 - f I S~~

~~Festuca ovina Potentilla flabellifolia V f I S Ix V _ ~~~~~f l S I x- 51 _f Vf I s 1_v 1IS Ixx 61 -~~

~~Saxifraga bronchialis Claytonia lanceolata~~

~~V f I S 61'/T _33~~

~~6/30 15 '30 8/15 8/30 83'715 7'30 8/is 8/30~~

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 145 position and the distributionof several important various species to gradual changes in microenviron- species across the entire range (Table 7). Some of ment along an alpine slope. Plant communitydata the herb and shrub species associated with the collected along the transect also indicate a gradual, krummholz stands are subalpine species that reach but notable, change in structure and composition their upper limits in these snow protected sites. (Fig. 8). The fellfield is characterized by sparse clumps of vegetation (total average cover of 21 %) Community-soilrelationships and moderate species richness (S, average of 20 species). In the ecotonal area between discontinuous Jenny (1941) stated that any soil property is a and continuous vegetation, species richness reaches function of the regional climate, parent materials, a maximum (S = 29). Total plant cover increases to topography,biota, and time. The vegetationof a re- 217%7while species richnessdecreases (S = 4) at the gion is also a functionof these factors (Major 1951). base of the slope. In the North Cascades, all of these factors,with the Soil temperatureand soil moisture measurements exception of the parent materials,vary considerably. monitored for two summers indicated that high This relatively uniform parent material is due, in soil temperatureand low soil moisture regimes are large part, to the extensive pyroclastic deposits typical of the ridgetopfellfield while lower tempera- present in the region. These deposits, mixed with tures and higher moisture levels occur downslope. the residuum of the various geologic strata, modify Soil temperaturedecreases slightly,while soil mois- the residuum to such an extent that they have no ture stress increases, with distance down the vege- detectable influence on the regional vegetation and tated portion of the slope during drought periods. soil patterns. This is in contrast to many regions The pattern of these environmental parameters is where ultramafic(Kruckeberg 1954, 1969; Whittaker likely due to the increased vegetative cover and 1954), sandstone-dolomite(Mooney et 1962), or al. greater evapotranspirationrates at the base of the calcareous (Bamberg and Major 1968) parent ma- slope. terials have marked effects on vegetation and soil Measurements of leaf i also indicate varying patterns. responses to slope environmentalgradients. Leaf f The pattern of alpine soil types in the North generally increased with distance downslope. Mea- Cascades generally corresponds to the vegetation surementsobtained on the upper slope (at 21 m) pattern. Beneath krummholz and heath vegetation, were generallybetween -14 and -18 bars, except cheluviation is a common process. This process is in the case of Lupinus latifoliuswith a low of -27 most intense in the western North Cascades where bars. The plants, from which the latter values were leached A2 horizons and iron-richB horizons are obtained, died back within several days, indicating typical. that Lupinus latifoliusprobably cannot tolerate leaf Inceptisols are typical of many of the community f much lower than that attained in Polygonum bis- types in the North Cascades, especially in the eastern tortoides(-15 to -18 bars). The highestleaf f (-5.2 part of the range. The most notable differences to -9.2 bars) were measured at the base of the slope. withinthe Inceptisolsare the chemical characteristics, These higher values indicate that the bulk of the which vary markedlyfrom west to east. The western water requirementsof the plants are being sufficiently soils usually have higher organic matter,cation ex- met from near the -30 cm level where soil moisture change capacity, and nutrientlevels, and are more stressis seldom,if ever, critical. acidic. The leaf f values may explain the distributionpat- Sites that are unstable and sparsely vegetated are tern and relative abundance of Lupinus latifolius, Carex characterized by Entisols. These soils usually have Polygonum bistortoides,and spectabilis along the gradient. At the base of the slope, where leaf f only shallow A-C profiles beneath vegetation and was never low (Table 9), Lupinus latifolius,Polygo- have low organic matter,cation exchange capacity, num bistortoides,and Carex spectabilis reach their and nutrientlevels. lushest and most vigorous growth,excluding almost all other plants. Farther upslope, (at 36 m) where Response of species to an environmentalgradient leaf f is lower, these three plants are still able to The environmentalgradient on Grouse Ridge pro- grow, but with reduced vigor. Habitat heterogeneity vided an opportunityto examine the response of thus increases resultingin increasingspecies richness.

FIG. 1L. Phenologicalpatterns of 12 plant species on Grouse Ridge,Mt. Baker,Washington during 1971 (upper bar) and 1972 (lower bar). Distance (m) downslopeappears on the ordinateaxis; monthand day are on the ab- scissa. Symbolsare: v-vegetativegrowth: solid bar-in flower;f-in fruit;s-seed dispersal:x-signs of dormancy.

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions GEORGE W. DOUGLAS AND L. C. BLISS Ecological Monographs 146 Vol. 47, No. 2 The plants occurring in the fellfield are adapted papers, although describingthe general vegetationof to an entirelydifferent set of environmentalfactors various regions, usually fail to document the relative than those downslope. Polygonum bistortoidesand abundance of the taxa, thus making it difficultto Carex spectabilisoccur only near the edge of the fell- recognize vegetationtypes for comparative purposes. field in large (1 to 2 M2) clumps. Since these clumps The followingdiscussion is based on the few studies are probably not snow-freeduring the winter,these that do allow comparisons with the North Cascadian plants do not have to endure the high winds, low communities. Future work will surely increase the temperatures,and frequent frost cycles common to geographic ranges of the communities presented the rest of the fellfield. The fellfieldspecies are also here. adapted to adverse summerconditions. Soil tempera- The range of alpine plant communitiesis not neces- tures and soil moisture stress are high and possibly sarily restrictedto the alpine zone. A number of mightexclude other plants even though they may be them have subalpine-alpinedistributions, both in the able to endure winterconditions. North Cascades and elsewhere. Tables 10 and 11 Observations showed that phenological phases are lend support for the inclusion of krummholzwithin closely related to time of snowmelt and early-season the alpine zone, at least in the North Cascades, be- temperatureregimes. The abilityof Claytonia lanceo- cause more of the communitiesand a larger segment lata to flowerwithin several days aftersnowmelt and of the flora associated with krummholzoccur in the complete its life cycle just before the vegetative alpine tundra above than in the tree-clumpmeadows canopy closes, at the base of the slope, is due in or subalpine zone below. large part to its abilityto initiategrowth beneath the A number of communitytypes may be restricted snow during fall or winter. Douglas and Taylor to the North Cascades. These include the Calama- (1972), also workingon Grouse Ridge, found Clay- grostis purpurascens, Eriogonum pyrolaefolium- tonia lanceolata relativelywell developed and in bud Luzula piperi, Danthonia intermedia,Carex breweri, under 2 m of snow. Kimball et al. (1973) found new and Carex capitata types. apical growthin early fall in Rocky Mountain popu- Of the snowbed communities,the Carex nigricans lations of Claytonia lanceolata. Other workers have type appears to be the most widespread. It occurs also noted the abilityof this and other alpine species in both the subalpine and alpine zones in the Cas- to initiate growth at near-freezingtemperatures be- cades of Oregon (Van Vechten 1960) and central neath snow (Billings and Bliss 1959; Mooney and Washington (Meredith 1972), the Olympic Moun- Billings 1961; Halleck and Wiens 1966: Spomer and tains of Washington (Bliss 1969; Kuramoto and Salisbury 1968; Bell 1973). The fellfieldspecies also Bliss 1970), southern British Columbia (Archer show early phenological development,enabling them 1963; Brooke et al. 1970; Eady 1971), north to to complete much of their seasonal growth before southern Alaska (Cooper 1942), and east to the conditionsbecome unfavorable. Canadian Rockies (Beder 1967; Hrapko 1970; Knanik et al. 1973). The Antennaria lanata com- Distributionof alpine and subalpine communitytypes munity,which also occurs in the subalpine zone of in westernNorth A merica the eastern Cascades, is found in the alpine zone of The numerous floristicworks dealing with various the Olympics (Bliss 1969) and the Canadian Rockies et al. regions of North America document the geographic (Beder 1967; Hrapko 1970; Knapik 1973). range of most alpine vascular plant taxa adequately. The Eriogonum pyrolaefolium-Luzula piperi com- restrictedto the North Cascades al- The North Cascadian flora is an exception. Recent munitymay be communities dominated collections have resulted in significantnew range ex- though similar, but drier, tensionsfor 20 alpine species in westernNorth Amer- by Eriogonum pyrolaefolium (but lacking Luzula) ica (Douglas and Taylor 1970: Douglas et al. 1973; have been reported from Oregon (Van Vechten Taylor et al. 1973). 1960). The Saxifraga tolmiei-Luzulapiperi type oc- The alpine flora of the North Cascades has curs only in the subalpine and alpine zones of the floristicaffinities with many regions. The strongest North Cascades and the nearby Coast Range of affinitiesare withthe arctic and cordilleranregions to British Columbia (McAvoy 1931, Brooke et al. the northand east. A smaller segmentof the flora is 1970). restrictedto the Pacific Coast, ranging from British Lush herb communities dominated by Festuca Columbia to northern California. The Cascadian viridula and Lupinus latifoliusare found in the sub- endemic elementthat ranges into the North Cascades alpine and alpine zones in, and south of, the North consists of only a few species. Cascades. Festuca viridula-Lupinuslatifolius (Frank- In contrast to our knowledge of plant ranges, lin and Dyrness 1973; Franklin et al. 1971) and informationon the abundance of a taxon in a par- Lupinus latifoliustypes (Meredith 1972) have been ticular region is conspicuously poor. A number of reportedon Mount Rainier,Washington. These types

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~~TABLE 10. Elevationaldistribution of alpine zone plantcommunities in threeregions (west, central, and east) of the NorthCascades Range~~

Elevational Region distribution-' West Central East Total Alpine tundra Carex breweri Carex breweri Carex nardina Carex nardina Carex capitata Salix nivalis Calamagrostis purpurascens Kobresia myosuroides 6 Alpinetundra + krummholz Phyllodoce Phyllodoce Phyllodoce glanduliflora glanduliflora glanduliflora Empetrum nigrum Empetrum nigrum Salix cascadensis Salix nivalis Salix nivalis Carex phaeocephala Salix cascadensis Salix cascadensis Dryas octopetala Carex phaeocephala Carex phaeocephala Carex scirpoidea Eriogonum-Luzula Dryas octopetala 8 Alpinetundra + krummholz+ tree clump/meadow Saxifraga-Luzula Carex nigricans Phyllodoce empetriformis Carex nigricans Cassiope mertensviana Arctostaplhylos u va-ursi Cassiope mertensiana Plhyllodoce A ntennarialanata empetriformis Phyllodoce Aretostaphylos Danthonia intermedia empetriformis uva-ursi Carex spectabilis A ntennarialanata A rctostaphylos uva-ursi 9 Krummholz + tree Lupinus latifolius clump/meadow Lupinus latifolius Festuca viridula 2 a Definitions:The treeclump/meadow zone or subalpinezone is definedas thatarea above the continuousforest and below the upperlimit of conifersas an uprighttree form (Douglas 1971, 1972). The krummholzzone is a nar- row band of dwarfedor prostrateconifer clumps interspersed with meadows and has been referredto in thispaper as the loweralpine zone. Above the krummholzis the alpinetundra or upperalpine zone.

have also been documented in the Three Sisters (Van nated by Festuca viridula. A similar Festuca (Fes- Vechten 1960) and Mt. Jefferson(Swedberg 1961) tuca idahoensis) type occurs in the subalpine zone of areas in Oregon. Farther east, in the Wallow Moun- the Olympic Mountains (Kuramoto and Bliss 1970). tains,Strickler (1961) has studied communitiesdomi- Several of the North Cascadian shrub types have wide geographic ranges. Dryas octopetala, a circumpolar species, occurs as a major dominant north to TABLE 11. Elevationaldistribution of alpinezone vascu- Alaska and the Yukon lar plant species in threeregions (west, central.and (Hanson 1951; Price 1971), east) of the NorthCascades Range east to the Rocky Mountains of Alberta (Beder 1967; Bryant and Scheinherg 1970; Hranko 1970; Knapik et al. 1973) and south in the Rockies to NUMBER OF SPECIES Region Colorado (Johnson and Billings 1962: Holwav and Ward 1965; Marr 1967; Bamherg and Maior 1968). Elevational All distribution West Central East regions The several heath types are also widely distributedin both the subalpineand alpine zones. They occur in the Alpinetundra' 7 13 17 26 Olympics (Kuramoto and Bliss 1970) the Cascades of Alpinetundra + krummholz 56 57 49 70 Oregon (Van Vechten 1960) and central Washington Alpinetundra + (Franklinet al. 1971; Meredith 1972). northto north- krummholz+ tree ern BritishColumbia clump/meadows 72 90 80 104 (McAvoy 1931; Archer 1963; Krummholz+ tree Brooke et al. 1970; Eady 1971; Welsh and Rigby clump/meadows 34 32 19 50 1971) and the southwesternYukon (G. W. Douglas, Total species 169 191 165 250 personal observation), and in the Rocky Mountains Definitions:see Table 11. of Alberta (Heusser 1956; Beder 1967; Hrapko 1970;

This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions GEORGE W. DOUGLAS AND L. C. BLISS EcologicalMonographs 148 Vol. 47, No. 2 Knapik et al. 1973) and Montana (Bamberg and specificationsfor constructionof the bridge-meter.The Major 1968). Cassiope tetragona, found mainly in followingtaxonomists kindly identified or verifieddiffi- cult taxa: C. D. Bird,A. Cronquist,G. G. Douglas, C. small clumps and on north aspects in the eastern Feddema,F. J. Hermann,C. L. Hitchcock,N. H. Holm- North Cascades, becomes a recognizable type farther gren,G. A. Mulligan,M. Ostafichuk,W. L. Peterson, north (northwesternBritish Columbia and the south- R. J.Taylor, and D. H. Vitt. westernYukon) and east (Rocky Mountains of Al- The cooperationand logistical supportprovided by berta) (Hrapko 1970; Welsh and Rigby 1971; the staffof North Cascades National Park is also ap- preciated. This study was supportedby National Re- Knapik et al. 1973; G. W. Douglas, personal observa- search Council Grant NRC A-4879 to Bliss. tion). Empetrum nigrum,a circumpolar species, oc- Special thanksare due to Gloria G. Douglas. Her curs as a communitytype in Alberta, the southwest- cheerfulaid duringthe longhours of fieldand laboratory ern Yukon, and northernAlaska (Bliss 1956; Hrapko workproved invaluable. 1970; G. W. Douglas, personal observation). The Salix nivalis communityhas been reportedelsewhere LITERATURE CITED as a major dominant from western Montana (Bam- Archer,A. C. 1963. Some synecologicalproblems in berg and Major 1968), and southwesternAlberta the alpine zone in Garabaldi Park. M.S. thesis. Univ. BritishColumbia, Vancouver,B.C. 129 p. (Knapik et al. 1973). The Salix cascadensis commu- Arno, F., and J. R. Habeck. 1972. Ecology of alpine nity is also rare in the literature,being documented larch (Larix lyallii Parl.) in the Pacific Northwest. only from Wyoming (Billings and Bliss 1959). The Ecol. Monogr.42:417-450. Arctostaphylosuva-ursi type has been reportedfrom Bamberg,S. A., and J. Major. 1968. Ecology of the western Montana by Bamberg and Major (1968). vegetationand soils associatedwith calcareous parent materialsin three alpine regionsof Montana. Ecol. Kobresia myosuroides,a wide-rangingcircumpolar Monogr. 38:127-167. species, has been reported as a dominant in many Beals, E. 1960. Forestbird communities in theApostle regions. This type has been described fromColorado Islands of Wisconsin. Wilson Bull. 72:156-181. to Alberta in the Rocky Mountains (Cox 1933; Marr Beder, K. 1967. Ecology of the alpine vegetationof Banff National Park, Alberta. 1967; Bamberg and Major 1968; Hrapko 1970; Bell Snow Creek Valley, M.S. thesis.Univ. of Calgary,Calgary, Alberta. 243 p. 1973; Knapik et al. 1973) and north to the Kluane Bell, K. L. 1973. Autecologyof Kobresia myosuro- Ranges of the southwesternYukon (G. W. Douglas, ides: why wintersnow accumulationpatterns affect personal observation) and Mt. McKinley in Alaska local distribution.Ph.D. thesis. Univ. of Alberta,Ed- (Hanson 1951). It also occurs in the Sierra Nevada monton,Alberta. 173 p. Billings,W. D., and L. C. Bliss. 1959. An alpinesnow- a species Mountains of California where it is disjunct bank environmentand its effectson vegetation,plant (Major and Bamberg 1963). Reports of other North development,and productivity.Ecology 40:388-397. Cascadian sedge types are sparse. Carex scirpoidea Bliss,L. C. 1956. A comparisonof plantdevelopment var. pseudoscirpoidea stands have been recorded in in microenvironmentsof arctic and alpine tundras. the Snowy Mountains of central Montana (Bamberg Ecol. Monogr.26:303-337. 1962. Adaptationsof arcticand alpine plants and Major 1968) and the Sierra Nevada Mountains to environmentalconditions. Arctic 15:117-144. in California (Major and Bamberg 1963). Carex 1963. Alpine plant communitiesof the Presi- nardina is reported as a dominant in the alpine of dentialRange, New Hampshire. Ecology 44:678-697. southwesternAlberta (Bryant and Scheinberg 1970). . 1966. Plant productivityin alpine microen- vironmentson Mount Washington,New Hampshire. The Carex spectabilis community appears to be Ecol. Monogr. 36:125-155. mainly restrictedto the subalpine and alpine zones of . 1969. Alpine communitypatterns in relation northwesternWashington and southern British Co- to environmentalparameters, p. 167-184. In K. N. H. lumbia (Kuramoto and Bliss 1970; Eady 1971; Doug- Greenridge[ed.] Essays in Plant Geographyand Ecol- las 1972) although it also occurs as an alpine snow- ogy. Nova Scotia Museum, Halifax, Nova Scotia. Bockheim,J. G. 1972. Effectsof alpine and subalpine bed communityin the Sierra Nevada Mountains (J. vegetationon soil development,Mount Baker, Wash- Major, personal communication). ington. Ph.D. thesis. Univ. of Washington,Seattle, In general, the communitiesrestricted to the west- Wash. 171 p. ern or central North Cascades have closer affinities Bouyoucos, G. J. 1951. A recalibrationof the hy- for makingmechanical analysis of to coastal areas both to the north and south. Those drometermethod soil. Agron.J. 43:434-438. communitiesrestricted to the easternNorth Cascades Bray,J. R., and J. T. Curtis. 1957. An ordinationof show closer affinitiesto Rocky Mountain and far upland forest communitiesof southernWisconsin. northernareas. Ecol. Monogr.27:325-349. Brink,V. C. 1959. A directionalchange in the sub- ACKNOWLEDGMENTS alpine forest-heathecotone in Garabaldi Park, British Columbia. Ecology40:10-16. Thanks are extendedto the manypeople who assisted British Columbia Department of Agriculture.1963. in the course of this study. Drs. J. G. Bockheim,S. Climateof BritishColumbia. Queens Printer,Victoria. Pawluk,and W. W. Pettapieceprovided suggestions and 53 p. aid withregard to soils. Dr. T. M. Ballard suppliedthe Brooke,R. C., E. B. Peterson,and V. J. Krajina. 1970.

~~This content downloaded from 128.193.8.24 on Tue, 27 Aug 2013 19:27:36 PM All use subject to JSTOR Terms and Conditions Spring 1977 ALPINE AND HIGH SUBALPINE COMMUNITIES 149~~

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