Structure of Alpine Plant Communities Near King's Peak, Uinta Mountains, Utah

Volume 42 Number 1 Article 3

3-31-1982

Structure of alpine plant communities near King's Peak, Uinta Mountains, Utah

George M. Briggs University of Montana, Missoula

James A. MacMahon Utah State University

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Recommended Citation Briggs, George M. and MacMahon, James A. (1982) "Structure of alpine plant communities near King's Peak, Uinta Mountains, Utah," Great Basin Naturalist: Vol. 42 : No. 1 , Article 3. Available at: https://scholarsarchive.byu.edu/gbn/vol42/iss1/3

This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. STRUCTURE OF ALPINE PLANT COMMUNITIES NEAR KING'S PEAK, UINTA MOUNTAINS, UTAH

George M. Briggs' and James A. MacMahon-

Abstract.- a study was made at 18 sites with elevations between 3512 and 3768 m in the Uinta Mountains, Utah. Sites were small in extent but typified vegetation patterns found in the Uintas. Standing crop, species composition (based on dry weight), and values for several physical parameters were determined at each site. Simple linear regressions performed between the various biotic and abiotic characters revealed significant relationships between the characteristics of rocks visible at the surface (the number, size, and variation in size) and vegetation cover. This relationship was probably due to the burial of rocks as a region became vegetated. Bray and Curtis ordinations performed on the indicated data that there were several factors which influenced the species composition but that no single factor dictated the vegetational pattern.

The Uinta Mountains of northeastern Utah on the order of 20 m2. Some of these changes are tte largest east-west trending range in can be attributed to microtopographical vari- North America. Much of the alpine and sub- ations (Billings 1979). In this study we de- alpine regions of the range are dominated by scribe the plant associations within a small members of the Cyperaceae (sedges). These area (< 1 km-) of the Uintas and topograph- sedge-dominated regions may be placed into ical and soil factors associated with these two categories: wetland areas and upland areas. areas. In a separate paper (Briggs and Mac- Mahon, in preparation) we discuss the struc- Study Area ture of some sedge-dominated wetlands in the Uintas. In this paper we discuss the high- The Uinta Mountains are in northeastern er plant composition, standing crop, and Utah at a latitude of 40°45' N. They trend al- physical factors at 18 upland sedge-domi- most directly east-west for a distance of 80 nated sites within a small region in the vicin- km (110-111°W). Bedrock throughout most ity of King's Peak. of the alpine portion of the range is a Pre- Hayward (1952) published a general de- cambrian quartzite. Because of the in- scription of the vegetation of the Uintas. accessibility of the Uinta alpine zone (i.e., Lewis (1970) studied the Uinta alpine vegeta- there are no roads), there are few studies of tion and described five alpine communities. the area. Climatic data from the region are Lewis felt that exposure, snowpack, and few but probably are similar to those for the moisture were important in determining the Front Range of the Colorado Rockies. Lewis structure of these commmiities. Several other (1970) estimated precipitation to vary be- workers have considered these factors to be tween 85 and 125 cm, with approximately important in determining plant community three-fourths of this falling as snow. structure in North American alpine regions We studied an area near King's Peak in the (Marr 1961, Holway and Ward 1963, Bliss central part of the range, at elevations of 1963, Webber et al. 1976). Flock (1978) 3512-3768 m (11,560-12,300 ft) (Fig. 1). showed that these factors were also impor- Much of this region consists of cliffs, debris tant to the distribution of lichens and bryo- slopes, and felsenmeere, but parts contain a phytes. Alpine areas also show variation on a well-developed alpine turf. Cryopedogenic smaller scale, with distinct vegetation regions processes are operating in the region, as

'Department of Botany, University of Montana, Missoula, Montana 59812. 'Department of Biology and the Ecology Center, Utah State University, Logan, Utah 84.322.

50 March 1982 Briggs, MacMahon: Alpine Plant Communities 51

nelsonii as a separate species based on dis- cussions with Mont Lewis and Arthur Holm- gren and on our own observations. Each alpine site was sampled along a single transect. The boundaries of the area sampled were subjectively set. The initial sample point was randomly chosen; sub- sequent sample points were regularly spaced. At each sampling point a 20 X 50 cm frame was put down and all the vascular plant ma- terial within the frame was clipped at ground level. If possible, the clipped plants were im- mediately sorted to species and placed in paper bags. Most samples could not be sorted in 4PltoP4 situ because of the wind. Samples not sorted in the field were placed in paper bags and sorted in the lab. After sorting, all samples were air dried for at least two months and XltoX7 then placed in a drying oven (40 C) for 24 hours and then weighed. Ten samples were collected from each alpine site. Field notes were taken as to the contents of each bag collected. The vegetative identification of Carex spp. was not as formidable as might be expected. There were only five species found on the sites (only three were common), rarely did more than two species occur in a single KILOMETER sample bag, and both Carex paysonis Clokey and C. rupestris All. are quite distinct Fig. 1. Map of the vicinity of King's Peak, showing the location of the 18 study sites. vegetatively. One problem facing investigators in both evidenced by stone circles and stripes. Al- Colorado and Utah is the separation of Carex though the vegetated regions often appear elynoides Holm, and Kobresia bellardii (All.) homogeneous from a distance, close in- Degland. These species are vegetatively very spection reveals changes in vegetation, mi- similar, occupy the same habitat, and fruit in- crotopography, and rockiness. The 18 study frequently. Separation is easy if fruiting ma- sites were chosen to illustrate several regions terial is present. In all samples having vegeta- distinguishable to the eye that commonly oc- tion of the Carex elynoides-Kobresia bellardii cur within this small area. These sites are type each individual fruiting stalk was care- typical of the alpine vegetation of the Uintas fully examined (there were from 0-25 fruit- in general. It should be emphasized that the ing heads/sample). All the heads examined size of the study sites was small (30-100 m-) were Kobresia bellardii, and, therefore, all in comparison to many phytosociological the vegetation of the Kobresia-C. elynoides studies but reflected a scale of vegetational type was considered to be Kobresia bellardii. change found in the region. At each site elevation, slope and aspect were measured. Soil samples were dug on 15 Soils were sampled at a Methods September 1975. depth of 5-10 cm, a depth approximating the Nomenclature follows Cronquist et al. middle of the rooting zone. Values for nitrate (1977) and Holmgren and Reveal (1966) ex- nitrogen, available phosphorus, and cation cept for Carex nekonii Mkze., which the exchange capacity were determined by the aforementioned authors have grouped with Utah State University Soil and Water Analy- Carex nova L. H. Bailey. We retain Carex sis Laboratory. Gravimetric percent water 52 Great Basin Naturalist Vol. 42, No. 1 was determined by weighing soil samples be- puterized version of the Bray and Curtis fore after and drying (percent = fresh method vVas used. Stands were compared, us- weight-dry weight/dry weight). The pH was ing the percentage similarity index (PS) determined using a pH meter. A textural where: analysis was performed by shaking the soils in a series of sieves for five minutes. The per- = ^^."^"(P^J'P^^O centage of soil, by weight, found in each of PS X 100 the sieves was recorded. A parameter for soil 2 (Pij + Pik) texture was calculated for the samples by giv- Pij = measurement of the ith species in ing each size class a weighting factor (1-6) the jth stand, and multiplying the percentage of soil in "ik = measurement of the ith species in each size class by the weighting factor, then the kth stand. summing the values for the six size classes. To The importance of each species was obtain absolute values for comparison to the indexed by its aboveground standing relative texture values, the finest and coarsest crop (dry weight). samples were analyzed by the Utah State Using the numerical University Soil and Water Analysis values which depict Laboratory. each site's placement on the ordination axis, simple linear regressions were run relating The percent cover of soil, rocks, vascular the vegetational plants, saxicolous lichens, and terricolous relationships of the sites (as depicted in the values for the ordination axes) lichens was determined by using the line in- to the various measured tercept method (Mueller-Dombois and Ellen- environmental parameters. berg 1974) on three 1 m lines within the sites. Possible relationships the The number and average surface area of the among various parameters measured at each site rocks encountered in these transects were were stud- recorded. ied through the construction of a correlation matrix that gave correlation coefficients for Ordination methods were used to relate simple, linear regressions run between the study sites to each other and to elucidate each pair of site parameters. the factors important in structuring the communities. The indirect gradient analysis of Bray and Curtis (1957) was chosen in hope of Results and Discussion determining the coenoclines operating in The results of the line intercept analysis these sedge-dominated regions. A com- (Table 1) show the cover percentage in each

Table 1. Standing crop and cover values for the alpine sites. 53 March 1982 Briggs, MacMahon: Alpine Plant Communities

fraction percent) were assumed of three categories. Vegetation cover varied nonsand (37 than 18 percent clay. This ap- from 20 to 99 percent. The amount of surface to be more These soils are considerably covered by rocks varied from to 55 per- pears unlikely.] than most other alpine soils studied. cent. The percent of available rock and soil coarser described soils of the Colorado covered by lichens is also shown in Table 1. Marr (1961) have only 35-59% sand. The values for the physical parameters Front Range which McConnell's study (1965) of measured at each site are given in Table 2. Nimlos and alpine soils describes textures much The soil data reflect a lack of soil devel- Montana those of the Uintas. A lack of soil opment. All of the sites were deficient in ni- finer than is expected in any alpine area trate nitrogen with values ranging from 0.1 development to the low temperatures and short grow- to 3.3 ppm. Phosphorus was also low, ranging due season. The fact that the Uinta soils are from 1.9 to 27 ppm. These values are lower ing poorly developed than other areas than the 11.2 to 42 ppm values reported by even more western United States is Nimlos and McConnell (1965) for Montana of alpine in the probably due to the quartzite bedrock which alpine soils. The cation exchange capacity of slowly and results in a sandy soil these soils ranged from 5.3 milli- weathers nutrients. equivalents/100 g soil to 33.3 me/ 100 g soil. that is low in cryopedogenic processes The cation exchange capacity seems high, es- It is obvious that in the Uintas (Lewis 1970). Be- pecially when considering the lack of clay in are operating these processes result in a size sorting the soil (see below). The high cation ex- cause fol- rocks, it was hoped that values for the change capacity is probably due to the pres- of parameters might reflect a particular ence of organic matter in the soil resulting lowing cryopedogenic process: mean from slow decomposition rates. stage of the rock size (cm^); number of rocks vis- The texture of all the soils was sandy. Man- surface at the surface; and the normalized varia- ual sifting gave values of 95 and 100 percent ible surface rock size. Values for these pa- sand. Automated sifting of the two extremes tion in alpine sites (Table 2). based on our texture scale gave values of 63 rameters varied at the was related to vegeta- and 85 percent sand. These values would de- Some of the variation noted that there appeared to be fine soils classified from sandy loams to tion. It was in community structure that loamy sands (Donahue et al. 1971). [The fin- two extremes related to surface rock characteristics. est soils might be classified a sandy clay if the were

rock characteristics for the alpine sites. Table 2. Values for soil parameters, slope, and surface 54 Great Basin Naturalist Vol. 42, No. 1

Some areas had a very dense turf with a few develops. If the surface rock characteristics large rocks visible at the surface. At the other were reflecting a cryopedogenic process, one extreme were areas of sparse vegetation with would expect a relationship between surface a large number of rocks of a variable size vis- rock characteristics and the percentage of ible at the surface. This observation is reflect- rocks and soil covered by lichens (cryope- ed in the correlation coefficients (Table 3), dogenesis causing instability in rock and soil where there were several significant correla- surfaces and thus a lack of lichens). Because tions between rock characteristics and stand- there was no significant relationship between ing crop and cover values. surface rock characteristics and the percent- The relationships between surface rock age of lichens on the soil or rocks, we feel characteristics and vegetation may partially that the interaction between vegetation and explain some of the correlations between sur- the surface rock characteristics involves face rock characteristics and soil parameters. burial. For example, texture was significantly The peak aboveground biomass varied (p < .05) related with mean rock size (Table from 37 to 206 g/m2 (Table 1). Lewis' (1970) 3). The finest soils were found in areas with data on the Uinta alpine zone gave standing large rocks. These were areas with high bio- crop values ranging from 48.2 g/m2 for mass, where organic matter was added to an Geitm-sedge communities to 83.4 g/m2 for otherwise very sandy soil. Carex-Kobresia-grass communities. The Uinta There are at least two possible explana- standing crop values are lower than those of tions for the significant relationships between other regions of North American alpine tun- surface rock characteristics and vegetation dra. Scott and Billings (1964) reported stand- (Table 3). These relationships could reflect a ing crop values ranging from 14 to 348 g/m2 link between cryopedogenesis (that will af- in the Beartooth Mountains of Wyoming; fect surface rock characteristics) and vegeta- most sites ranged from 100 to 200 g/m2. Thi- tion, a situation shown by Johnson and Bil- lenius (1975) reported an aboveground stand- lings (1962). A second possibility is that the ing crop value of 223 g/m2 in the Medicine relationship between vegetation and surface Bow Mountains of Wyoming. The low stand- rock characteristics is due to a simple process ing crop values in the Uintas may be attri- of burial of all but the largest rocks as a turf buted to the poor soil development. One

Table 3. Correlation matrix for site parameters giving the r value for a simple linear regression between each pair of factors. An asterisk (°) indicates significance at the 0.05 level. 55 March 1982 Briggs, MacMahon: Alpine Plant Communities

for a site). The number of dominants at any possibility is that the sandy texture of these site varied from 2 to 5. soils allows for little water storage, thereby one dominant species of the Uinta increasing the chance of drought-stress. Most Most of the are dominants of other areas of west- of the areas we studied had little winter alpine (R.Br.)Ser. snowpack and were dependent on summer ern alpine regions. Geum rossii dominate portions of the thimderstorms as a source of water. Such and Carex rupestris Wyoming (Scott and Bil- thimderstorms are common in the Uintas, but Beartooth Range of and Niwot Ridge in Colorado our observations show that the region some- lings 1964) Kobresia bellardii is common on times goes without rainfall for over a week, (Marr 1961). Ridge but absent in Wyoming. Carex in which case the low water-storage capacity Niwot is the only dominant in the Uintas of these soils might be important. Data on paijsonis is not a common dominant in other west rainfall and soil water potential would be that ern alpine regions. needed to see if drought is indeed an impor- sites we studied fall into three of the tant factor. Another way in which the poor The communities that Lewis (1970) described: soil development might affect aboveground and cushion plant commu- standing crop in the Uinta alpine is through Carex rupestris communities, and sedge- low nutrient levels. Our data did not suggest nities, Geum-sedge communities. As Lewis points out, these a relationship between nutrient levels and grass are far from discrete and several standing crop (Tables 1, 2, and 3), nor did it communities are "transitional" between his show that the Uinta alpine was substantially of our sites types. Moreover, because of lower in nutrients than some other alpine basic commimity limited size and relative homogeneity of areas. Our soil sampling was not extensive, the any worker studying the and perhaps more sampling of the nutrient the area we studied, of the whole range probably levels in these soils would show them to be vegetation have lumped the entire region into critical. would Geujn-sedge. Close study of Forty-two plant species were sampled on one community: this area reveals variation both in vegetation the 18 sites (Table 4). The number of species several physical factors. In an effort to on any one site varied from 8 to 17. Of the 42 and in variation in physical factors with species, 16 were dominants (having 5 percent relate the in vegetation, and also to better or more of the aboveground standing crop variation

Table 3 56 Great Basin Naturalist Vol. 42, No. 1

compare the different sites, we utilized ordi- Ordinations of all 18 sites were similar if nation techniques. Ordination techniques or- importance values from all species were used der stands on the basis of their vegetational or if only the importance values from the similarities. stand is Each given a numerical dominant species were used. An all-species value on one or several axes. The axis values ordination is illustrated (Fig. 2). ER is clearly indicate the site's position in a vegetational separated in the x-axis and HI, H2, H4, and space (Beals 1973). In the Bray and Curtis or- G2 on the y-axis. This separation was ex- dination, the end stands of the first axis (the pected because these sites were dominated X-axis) are the two stands with the lowest per- by species not present on other sites: Carex cent similarity. All the other stands are ar- nelsonii on ER, and C. paysonis on HI, H2, ranged relative to the first two. Stands that H4, and G2. have high a percent similarity have similar x- Although a significant correlation axes values. The second axis (the y-axis) is (r = 0.63) was found between the percent produced by selecting two stands in the cen- water in the soil and a site's position on the x- ter of the X-axis and making them end stands. axis of these ordinations (Table 5), this corre- Again, all stands are arranged relative to lation is due solely to the site ER. This site these end stands. was widely separated in the ordination and

Table 4. Species found on the alpine sites. Asterisks indicate that the species constituted greater than 5 percent of the aboveground standing crop.

HI H2 H3 H4 PI P2 P3 Getim rossii (R. Br.) Ser. Carex paysonis Clokey Deschampsia cespitosa (L.) Beauv. Polygonum vivipartan L. P. bistortoides Piirsh Artemisia scopulorum A. Gray Potentilla spp. Caltha leptosepala DC. Poa fendleriana (Steud.) Vasey Festtica ovina L. Erigeron simplex Greene Agropyron scribneri Vasey Trisetum spicatum (L.) Richt. Poa alpina L. P. rttpicola Nash Carex rupestris All.

Eritrichitim naniim (Vill.) Schrad. Trifoliiim parryi A. Gray Carex pseudoscirpoidea Rydb. Hymenoxys grandiflora (forr. & Gray) Parker Smelowskia cahjcina C. A. Meyer Draba spp. Silene acaulis L. Kobresia bellardii (All.) Degland Arenaria obtusiloba (Rydb.) Fernd. Paronychia pulvinata A. Gray Danthonia intermedia Vasey Agrostis humilis Vasey Salix nivalis Hook. Ca'itilleja pidchcUa Rydb. Luzula spicata DC. Carex misandra R. Br. C. nelsonii Mkze. Lloydia serotina Reichb. Eriophorum chamissonis C. A. Meyer Antennaria alpina (L.) Gaertn. Jtincus parryi Engelni. March 1982 Briggs, MacMahon: Alpine Plant Communities 57 had four times the percent water of any other The vegetation of these regions does not of the site pa- site (Table 2). EUmination of this site reduced appear to be ordered on any there do ap- the r to 0.03. In a similar manner a site's po- rameters we studied, although certain sition on the y-axis of the 18 site ordinations pear to be specific relationships with was significantly associated with texture, cov- sites (e.g., nearby springs producing sites like vari- er values, and standing crop. These repre- ER, slopes producing sites like G2). The sented relationships between these parame- ation in the vegetation of the region as a tolerances and ters and the sites HI, H2, H4, and G2. To see whole is dependent upon the individual species (Gleason if specific trends for the other sites might be- capabilities of come apparent, ordinations were run with 17 1939). For example, the distribution of Ko- areas of low sites (eliminating ER) and with 13 sites (elim- bresia bellardii is associated with inating ER and H1-H4). Although there were snow accumulation (Bell and Bliss 1979). In some significant relationships between site the alpine areas that we studied it appears parameters and ordination axis values, these that a variety of different factors are limiting represented separation of end stands from the the distribution of plant species and that no distribution of rest of the sites and not general trends within one factor is critical to the the data as a whole. several species as a group.

Table 4 continued.

P4 XI X2 X3 X4 X5 X6 X7 Gl G2 ER 58 Great Basin Naturalist Vol. 42, No. 1

Bliss, L. C. 1963. Alpine plant communities of the Pres- 100 idential Range, New Hampshire. Ecology 44:678-697. Bray, R., J. and J. T. Curtis. 1957. An ordination of the upland forest communities of 80- southern Wiscon- sin. Ecological Monographs 27:325-349. Cronquist, a., a. H. Holmgren, N. H. Holmgren, J. L. Reveal, and P. K. Holmgren. 1977. Inter- 60- >XI mountain flora: vascular plants of the Inter- mountain West. Vol. 6. Columbia Univ. Press, New York. 584 pp. R. L., Donahue, J. C. Shickluna, and L. S. Robertson. 40- 'xe 1971. Soils: €R .X4 . an introduction to soils and plant yV^'^ P3 'XZ growth. Prentice-Hall, Englewood Cliffs, New •X3 Jersey. H4 'Gl Flock, W. 1978. Lichen-bryophyte distribution along 20- J. a snow-cover-soil-moisture gradient, Niwot •HI Ridge, Colorado. Arctic and .'Alpine Research G2 10:31-45. H2^ Gleason, H. a. 1939. The individualistic concept of the 20 40 60 80 100 plant association. .'American Midland Naturalist. X-AXIS 21:92-110. Hayward, C. L. 1952. Alpine and biotic communities of Fig. 2. Ordination of all 18 sites studied, using all spe- the Uinta Mountains. Ecological Monographs cies sampled. 22:93-118. A. H., L. Holmgren, and J. Reveal. 1966. Checklist of Literature Cited the vascular plants of the Intermountain Region. U.S. Forest Service Research Report INT-32. In- Beals, E. W. 1973. Ordination: mathematical elegance termountain Forest and Range Experiment Sta- and ecological naivete. Journal of Ecology tion, Ogden, Utah. 160 pp. 61:23-35. HoLWAY, J. C, AND R. T. Ward. 1963. Snow and melt- Bell, K. L., and L. C. Bliss. 1979. Autecology of Ko- water effects in an area of Colorado alpine. bresia bellardii: why winter snow accumulation American Midland Naturalist 69:189-197. limits local distribution. Ecological Monographs Johnson, P. L., and W. D. Billings. 1962. The alpine 49:377-402. vegetation of the Beartooth Plateau in relation to Billings, W. D. 1979. High mountain ecosystems. Evo- cryopedogenic processes and patterns. Ecological lution, structure, operation, and maintenance. Monographs 32:105-135. Pages 97-125 in P. J. Webber, ed., High altitude Lewis, M. E. 1970. Alpine rangelands of the Uinta geoecology. AAAS Selected Symposium 12. Mountains, Ashley and Wasatch national forests.

Table 5. R values for simple linear regressions ran between ordination axes and site parameters. An asterisk (°) indicates significance at the 0.05 level.

All 18 sites

All species Important species Factor y

Phosphonis .37 Nitrogen Cation exchange pH Water (%) Texture Rocks # Rock size x Rock s/x slope

Standing crop Veg. cover Soil cover Rock cover

Soil covered by lichen (° Rock covered by lichen March 1982 Briggs, MacMahon: Alpine Plant Communities 59

F. 1975. Plant production of three high- United States Department of Agriculture, Ogden, Thilenius, J. elevation ecosystems. Pages 60-75 in D. H. Utah. 75 pp. 1961. Ecosystems of the east slope of the Knight, coord.. The Medicine Bow ecology proj- Marr, J. W. Colorado Front Range. Univ. of Colorado Studies ect, final report, February 28, 1975. Univ. of for Division of Series in Biology, No. 8. Univ. of Colorado Press, Wyoming, Laramie, Wyoming, Resource Management, Boulder, Colorado. 134 pp. Atmosphere and Water MuELLER-DoMBOis, D., AND H. Ellenberg. 1974. Aims Bureau of Reclamation, U.S. Dept. Interior, Den- and methods of vegetation ecology. John Wiley ver, Colorado. P. C. Emerick, D. C. Ebert May, and V. and Sons, New York. 547 pp. Webber, J., J. R. C. McCoNNELL. 1965. Alpine soils Komarkova. 1976. The impact of increased NiMLOs, T. J., AND 201-255 in of Montana. Soil Science 99::310-321. snowfall on alpine vegetation. Pages Steinhoff and D. Ives, eds., Ecological Scott, D., and W. D. Billings. 1964. Effects of envi- H. W. J. ronmental factors on standing crop and produc- impacts of snowpack augmentation in the San tivity of an alpine tundra. Ecological Mon- Juan Mountains of Colorado. Colorado State ographs 34:243-270. Univ. Press, Ft. Collins.

Table 5 continued.