Site characteristics and habitat requirements of the endangered dwarf bear-claw poppy ( Arctomecon humilis Coville, Papaveraceae)

Arctomecon humilis Cov. is a narrow endemic, confined to gypsiferous substrates derived from the Shnabkaib Member of the Moenkopi Formation in southwestern Utah. The characteristics of seven A. humilis sites were studied to define habitat requirements of the species. Both physical and biotic aspects of the habitat were analyzed; geology, soil chemistry, and physical properties, as well as vascular and nonvascular plant communities, were studied. Chemical and physical properties of these soils vary considerably from those supporting adjacent desert-shrub communities. The dominant vascular species on A. humilis sites are shadscale and Mormon tea. It was found that A. humilis occurred in portions of the habitat where shrubs were relatively less dense. A soil-surface, cryptogamic community contributed 84% or more of the total living cover on sites that supported A. humilis . Species composition of the cryptogamic community was highly similar among sites. Likewise, composition of the cryptogamic cover was similar when random samples were compared with samples centered on A. humilis plants. The Purgatory Flat site, which does not support the poppy, seems inseparable from A. humilis sites, in respect to soil characteristics and composition of the associated plant cover. There is reason to believe an A. humilis population could be established at the Purgatory Flat site.     

Foliage biomass and cover relationships between tree- and shrub-dominated communities in pinyon-juniper woodlands

Woodlands dominated by singleleaf pinyon ( Pinus monophylla Torr.and Frem.) and Utah ( Juniperus osteosperma [Torr.] Little) cover extensive areas in the Great Basin and Southwest. Both species are aggressive and can nearly eliminate the previous shrub-dominated community. Successional pathways from shrub-dominated communities before tree establishment to the tree-dominated communities that follow are known only for a few specific sites. How site growing conditions affect successional patterns needs further study. We compared the relationship of foliage biomass and percentage of cover between paired shrub-dominated and tree-dominated plots over several sites. Sites studied are from different elevation and topographic conditions on one mountain range. Foliage biomass in shrub-dominated plots had about a three-to-one variation over the range of site conditions sampled. Tree-dominated plots varied by about two-to-one. Cover in shrub-dominated plots had a four-to-one variation; cover in the tree-dominated plots varied by about two-to-one. Total foliage biomass in both tree- and shrub-dominated plots correlated best with the site index of height at 200 years of age. Variation in percentage of cover in both tree and shrub-dominated plots correlated best with elevation. Foliage biomass variation in shrub-dominated plots was proportional to the variation in the paired tree-dominated plots. A similar proportional relationship was present for percentage of cover between paired tree- and shrub-dominated plots. Foliage biomass was more sensitive to topographic differences than to cover. Variation in plant species sampled in the shrub-dominated plots correlated with total foliage biomass of the same plots. Species sampled also correlated with pinyon height at 200 years of age and total foliage biomass in the paired tree-dominated plots.     

Habitat and community relationships of cliffrose ( Cowania mexicana var. stansburiana ) in central Utah

Cliffrose ( Cowania mexicana var. stansburiana [Torr.] Jepson) community measurements were taken in central Utah. Data revealed a high between-site similarity of 78.5%. Soil analysis for sites showed most macronutrients, and some micronutrients, relatively low. Cover of cliffrose was found to increase with increases in soil magnesium (p ≤ 0.01). Plants growing on the sites have adapted life cycles to exploit moisture and nutrients during seasons of maximum availability. Prevalent species in the community were cheatgrass ( Bromus tectorum ), cliffrose, madwort ( Alyssum alyssoides ), and bluebunch wheatgrass ( Agropyron spicatum ). Annual grasses were the most important life form to community composition; the second was shrubs. Ratios between soil nutrients and cliffrose tissue nutrients indicate active transport of some elements. Data indicated a steady decline in establishment of new cliffrose individuals on the sites since 1957. This lack of reproductive success is most likely due to a combination of factors but appears most influenced by the elevated levels of annual plants (mainly cheatgrass) on the sites. If the cliffrose communities in central Utah are to be maintained, special attention to their management must be considered and implemented.     

Habitat relationships of Glaux maritima in central Utah

Thirty-five study sites were established in the meadow communities surrounding Utah Lake in central Utah. The study sites ranged across several community types. Glaux maritima was found in all sites but varied as to its ecological importance in these communities. Sixteen soil factors were measured relative to the stands studied. Cover of Glaux maritima correlated with parts per million sodium and total soluble salts in the soil. No other factors correlated significantly with the cover of Glaux maritima. Glaux maritima occupied only those sites with high levels of moisture throughout the growing season. The high moisture levels came from springs, seeps, elevated water tables, and early seasonal inundation. High levels of Glaux maritima cover corresponded to low numbers of species in the habitat.        

Vegetation and soil factors in the relation to slope position on foothill knolls in the Uinta Basin of Utah

Vegetation and soil differences with respect to slope position were studied on foothill knolls in the Uinta Basin of Utah. Plant communities on windswept ridges (top of slope) exhibited several unique characteristics when compared to the other slope communities. These communities at the top and base of slopes were sufficiently different in respect to plant life form composition, plant cover, wind-adapted growth forms, and percent exposed rock that they should be considered separate community types. Mineral concentrations in plant tissue and soil samples declined downslope in some cases and increased in others. Diversity decreased downslope as shrubs became dominant over grasses and forbs. Management of these communities should require special consideration due to the changes in the community structure with slope position.     

Cryptogamic soil crusts: recovery from grazing near Camp Floyd State Park, Utah, USA

The effects of grazing on the cryptogamic and vascular plant communities at two sites near Camp Floyd State Park, Utah County, Utah, were studied. The grazed site was subject to heavy grazing up until seven years prior to the study. The ungrazed site within the park boundaries had been protected from grazing for 20 years prior to the study and had a well-developed algal-lichen-moss crust. We found that the algae of the grazed site had recovered in terms of degree of crusting. There were no significant differences in the algal communities of the two sites when prevalent species were used as blocks in the ANOVAR analysis. However, when major algal groups were used as blocks, the analysis was significant, with the more recently grazed site having lower algal frequency. This difference, together with a few compositional differences, indicates that, although the algal community seven years following grazing is very similar to the algal community free of grazing for 20 years, the seven-year site is still in the process of recovery and community development. The diatom collections had a higher density in the grazed site, though the difference was not significant. Recovery of the lichen and moss community was not complete. The lichen Collema tenax and the mosses Bryum pallescens and Tortula ruralis were all significantly more abundant in the ungrazed area. Total cover of the lichen and moss components of the soil crusts was significantly lower in the more recently grazed area. Vascular cover was also lower.     

Pinyon-juniper woodlands in Zion National Park, Utah

Juniperus osteosperma-Pinus monophylla or P. edulis (P-J) woodlands are the most widespread plant community in Zion National Park (ZNP), southwestern Utah. These woodlands dominate nearly half of the park's land area. Our study of this vegetational complex is based on a sample consisting of 115 macroplots (each 0.01 ha in area) objectively distributed across the entire area of ZNP. We recognize 3 subtypes within the P-J complex: Juniperus osteosperma (Utah juniper) alone, juniper with P. monophylla (single-leaf pinyon), and juniper with P. edulis (two-leaf pinyon). The 2 pinyon pines rarely occur together, and thus the foregoing subtypes do not overlap geographically to a significant extent. The first 2 subtypes occur primarily below 1800 m elevation, while the latter is most commonly found above that elevation. Because of the scarcity of sizable expanses (over ～ 10 ha) of well-developed soils in ZNP, the P-J complex occurs primarily on sites where exposed bedrock covers a large portion of the habitat. As a result, over 90% of stands assigned to the P-J complex support less than 50% tree canopy cover (64% have less than 25% tree cover). Shrub cover increases along the woodland successional gradient. Pinyon cover increases faster than juniper cover. Microbiotic soil crust cover is consistently greater in J. osteosperma-P. monophylla woodlands than in J. osteosperma-P. edulis woodlands, but total living cover increases significantly along the successional gradient in both communities. To enhance plant and animal biodiversity, we recommend that pinyon-juniper woodlands of Zion National Park be managed so that late seral stages do not dominate large tracts.     

Effects of grazing exclusions on rangeland vegetation and soils, east central Idaho

Nineteen exclosures on sagebrush steppe and shadscale rangelands, varying in age from 18 to 38 years, were sampled for plant species richness, plant composition, indicators of soil erosion, ground cover, vegetative cover, and herb-low shrub layer screening cover. Features within the exclosures were compared with adjacent sites of the same size that were open to grazing by livestock and wildlife. Species richness typically was slightly greater inside exclosures than in adjacent grazed sites (median = 2 more species inside exclosures), but the difference was not significant ( P = 0.16). Similarity of plant community composition between exclosures and adjacent grazed sites ranged from 45% to 82%. Evidences of soil movement, soil pedestals, and soil flow patterns were all more pronounced outside exclosures than inside ( P ≤ 0.02), even though many sites were on flat to mild slopes (median slope = 12%). Meta-analysis of the 19 exclosure sites indicated that grazing exclusion resulted in less bare ground cover compared with adjacent grazed sites ( P ≤ 0.05). The effect of grazing exclusion on visible soil surface cryptogams was significant ( P ≤ 0.05), with generally greater cover inside exclosures. Cryptogam cover differences between grazed sites and exclosures tended to increase with the number of years of grazing exclusion ( r = 0.64, P = 0.046). Pseudoroegneria spicata , a principal livestock forage, averaged greater basal cover inside exclosures than outside on 4 of 10 sites where it occurred, although no exclosure sites had greater P. spicata cover on grazed sites. Meta-analysis of the 10 sites indicated that grazing exclusion resulted in greater P. spicata cover compared with adjacent grazed areas ( P ≤ 0.05). Poa secunda , a short-growing grass that initiates growth early in the spring and is not important livestock forage, averaged greater basal cover outside exclosures on 5 of 15 sites where it occurred. Meta-analysis of the 15 sites indicated a significant treatment effect ( P ≤ 0.05), with greater Poa secunda basal cover outside exclosures. Grazing exclusion resulted in greater screening cover in the herb-low shrub layer (0-0.5 m height; P ≤ 0.05). These results indicate that despite improved livestock grazing management over the past half century, livestock grazing still can limit the potential of native plant communities in sagebrush steppe ecosystems, and that the health of semiarid ecosystems can improve with livestock exclusion in the absence of other disturbances. A few exclosure sites were similar for the measured parameters, suggesting that these sites were ecologically stable and that exclusion of livestock grazing was not sufficient to move succession toward more pristine conditions, at least within the time periods studied. Managed disturbance such as fire or mechanical brush treatments may be necessary to restore herb productivity on these ecologically stable sites.     

Grazing impacts on sagebrush communities of central Utah

Twenty-three study sites were established in the sagebrush communities bordering Utah Lake. Relic (ungrazed) and grazed stands were represented in the sample. Differences in species composition, vegetation, and soil characteristics were assessed. Major differences in species composition and vegetative characteristics were due to the influence of grazing. Major changes were loss of native perennial grass cover, and increases in cover from introduced annual species. Differences in the soil characteristics were due to habitat rather than grazing influences.     

Understory seed rain in harvested pinyon-juniper woodlands

Seed rain was collected on six paired tree harvest and undisturbed plots in singleleaf pinyon ( Pinus monophylla )–Utah juniper ( Juniperus osteosperma ) stands. Approximately 14,600 seeds were collected during four years. Seed rain in undisturbed plots was similar to levels in mixed forest communities. Seed rain on harvest plots was similar to disturbed sites and grasslands. Seed rain levels reflect the current successional stage rather than the climax community type for the site. Seed rain increased in numbers and seed production per unit of plant cover following tree removal and especially on transition soil microsites. Only three to four of the plant species present on a site contributed greater than 10% of the total seed rain. Seed rain composition was similar on harvest and undisturbed plots (Jaccard Similarity Index Values = 47% to 67%) and explains in part the rapid reestablishment of predisturbance understory communities.     

Standing crops and dynamics of phytomass and minerals in two salt desert shrub communities

Of two salt desert shrub communities studied in Curlew Valley, Utah, the Atriplex confertifolia- dominated community had 15% greater total midsummer phytomass than the Ceratoides lanata community. The larger Atriplex shrubs contained much more woody tissue for support of photosynthetic tissues than did Ceratoides. Atriplex aboveground phytomass and litter were about twice those of Ceratoides. Ceratoides litter was generally fine and easily decomposable, but Atriplex litter contained about equal proportions of coarse, resistant woody tissues and fine, easily decomposable material. Atriplex root phytomass was 1.3 times that of Ceratoides at the 2–30 cm depth, but at depths below 30 cm, Ceratoides exhibited up to three times greater root phytomass and had 23% more root mass overall. Net aboveground community primary production was estimated to be about one-third greater in the Atriplex than Ceratoides community. Turnover times for readily decomposable aboveground litter were quite similar, but, because Atriplex produced coarser litter, its overall rate was somewhat slower than that of Ceratoides. Analyses of selected minerals in plant parts, litter, and soil revealed that about 90% of the mineral capital is in the soil, mostly within organic matter. Nearly equivalent pools of mineral elements were found in the two communities, except for greater Na in the Atriplex community.     

Comparison of vegetation patterns resulting from bulldozing and two-way chaining on a Utah pinyon-juniper big game range

Two adjacent mechanically treated pinyon-juniper ( Pinus spp. and Juniperus spp.) big game winter range sites in central Utah were sampled in 1981 to estimate vegetational differences and tree mortality from the two treatments. One site was treated by selectively bulldozing in 1957 and the other was double chained in 1965. Both treatments significantly reduced tree and litter cover, whereas significant increases were found for native grasses and shrubs compared to a nearby untreated site. Juniper cover for the untreated site was 35.5% compared to only 1.4% for the bulldozed area and 4.1% for the two-way chained area. Browse species densities were increased by the mechanical treatments. The use of different mechanical treatments on separate smaller portions of critical areas of big game winter range would help provide: (1) for both long-term and short-term use of a critical wintering area, (2) greater overall productivity and carrying capacity, and (3) greater diversity by creating more edge effect between the differently treated and untreated areas.     

Diamond Pond, Harney County, Oregon: vegetation history and water table in the eastern Oregon desert

Cores obtained in 1978 from Diamond Pond, Diamond Craters, Harney County, Oregon, as part of the Steens Mountain Prehistory Project, provide a record of vegetation change on the sagebrush/shadscale ecotone and of local and perhaps regional water tables. Pollen, macrofossils, sediments, and charcoal from these radiocarbon-dated cores were analyzed. Varying abundance of juniper, grass, sagebrush, and greasewood pollen, and of aquatic to littoral plant macrofossils reflects changing regional effective moisture and local water table since 6000 B. P. Eleven dates spanning 5200 radiocarbon years and four regionally correlated volcanic ashes establish the dating of seven periods of different moisture regimes: 1. Greasewood and saltbush pollen dominance before 5400 B. P. indicates shadscale desert. Rapid accumulation of alternating silts and medium sands lacking aquatic plant macrofossils and pollen reflects periods of ephemeral ponds with water table 17 m below the present level and considerable erosion of maar slopes. 2. Increasing sagebrush pollen from 5400 to 4000 B. P. indicates sagebrush expansion into shadscale desert. Scirpus, Rumex, Ceratophyllum, and Polygonum persicaria macrofossils and finely laminated clayey silts evidence perennial pond. 3. From 4000 to 2000 B. P. abundant juniper and grass pollen reflects extensive juniper grasslands (juniper seeds from trees growing nearby fell into the pond during this period). Rising charcoal values indicate greater importance of fire. Deepest late-Holocene pond ca 3700 B. P. corresponds with postulated intensive human occupation of northern Great Basin marsh and lake locales. 4. Between 2000 and 1400 B. P. increased sagebrush pollen mirrors reduced effective moisture and reexpanding sagebrush steppe. More abundant Scirpus and Rumex macrofossils evidence shallow pond. 5. From 1400 to 900 B. P. more numerous grass pollen indicates returning greater effective moisture resulting in deeper water with abundant Potamogeton . 6. About 500 B. P. increased greasewood and saltbush pollen evidences drought. Ruppia seeds and pollen and the mollusk Musculium indicate shallow, brackish water. 7. Abundant juniper and grass pollen reflects moister conditions between 300 and 150 B. P. Numerous Ceratophyllum fruits indicate deeper, freshened water. Since the mid- 1800s man and changing climate have encouraged sagebrush reexpansion. Increased Scirpus macrofossils indicate shallower water.     

Vegetative and edaphic factors affecting abundance and distribution of small mammals in southeast Oregon

The relationships between vegetative and edaphic habitat factors and the local distribution and abundance of small mammals on Malheur National Wildlife Refuge, Harney County, Oregon, were examined between July 1973 and June 1975. Of 16 species of small mammals captured, deer mice ( Peromyscus maniculatus ), montane voles ( Microtus montanus ), Great Basin pocket mice ( Perognathus parvus ), and least chipmunks ( Eutamias minimus ) comprised 90.1 percent of the individuals. The physiognomy of the vegetation was a factor in the distribution of rodent species other than deer mice. Pocket mice and chipmunks were restricted to the communities dominated by sagebrush ( Artemisia tridentata ) or greasewood ( Sarcobatus vermiculatus ). Population densities of pocket mice and chipmunks were significantly related to edaphic factors such as soil depth, texture, and strength, which may have affected the construction and stability of burrows. Montane voles occurred only in marsh or grassland communities. Population densities of voles were directly correlated with the amount of cover and inversely correlated with its patchiness. Deer mice were the most common species encountered and occurred in all but the grassland communities. The density of this species was related to vegetative or edaphic factors only seasonally or in certain habitats, and few generalizations could be made.     

Response of winterfat ( Ceratoides lanata ) communities to release from grazing pressure

Sixteen study sites were established in grazed and ungrazed stands of winterfat in Kane County, Utah. The area is located within the winter range of cattle and along U.S. Highway 89 between Kanab, Utah, and Page, Arizona. Road construction in 1957 dissected several winterfat communities, and following fencing part of the communities were released from grazing. Differences in species composition, vegetation, and soil characteristics between grazed and ungrazed sites were assessed. Major differences in site characteristics appeared due to the influence of winter grazing by cattle. Winterfat and Indian ricegrass showed increased cover on the nongrazed sites following release from grazing pressure. Winterfat also showed significant negative interspecific association patterns with all major species.     

Habitat relationships of saltcedar ( Tamarix ramosissima ) in central Utah

Nineteen study sites were established in areas infested with saltcedar bordering Utah Lake in central Utah. Saltcedar cover on the sites averaged 57% but varied widely from community to community. Seventeen soil factors were measured relative to the stands studied. Cover of saltcedar was regressed against the different soil factors, but no patterns were detected. Saltcedar functioned equally well at all levels of each gradient studied and appeared able to accommodate wide variations in all factors studied. It is suggested that saltcedar has evolved a general-purpose genotype that contributes to its being a vigorous and troublesome weed. Criteria as to why it is such an aggressive weed are listed.     

Leaf area ratios for selected rangeland plant species

Leaf area estimates are required by hydrologic erosion, and growth/yield simulation models and are important to the understanding of transpiration interception, CO 2 fixation, and the energy balance for native plant communities. Leaf biomass (g) to leaf area (mm 2 ) linear regression relationships were evaluated for 15 perennial grasses, 12 shrubs, and 1 tree. The slope coefficient (β 0 ) of the linear regression equation is a ratio of leaf area to leaf biomass and is defined as the leaf area ratio [LAR = one-sided leaf area (mm 2 )/oven-dry leaf weight (g)]. LAR represents β 0 in each regression equation, where Y = β 0 (X). Linear regression relationships for leaf area were computed ( r 2 = .84-.98) for all 28 native range species after full leaf extension. Within-plant estimates of leaf area for mesquite ( Prosopis glandulosae Torr. var. glandulosae [Torr.] Cockll.) or lime prickly ash ( Zanthoxylum fagara [L.] Sarg.) were not significantly different ( P ≤ .05). LARs for three of the shrubs and the tree were established at four different phenological stages. There were no significant differences ( P ≤ .05) in LARs for lime prickly ash, mesquite, and Texas persimmon ( Diospyros texana Scheele) after full leaf extension during the growing season. The LAR relationship for Texas persimmon changed significantly after full leaf extension. LAR relationships for Texas colubrina ( Colubrina texensis [T. & G.] Gray) changed in response to water stress.     

Beetles from the environs of Lake Powell in southern Utah and northern Arizona

Sixty-eight species of beetles of 14 families were collected in pit traps in 12 major vegetative communities during environmental monitoring studies in the summers of 1971 to 1973 in southern Utah and northern Arizona. Seasonal and plant community differences and correlations in population and composition were noted for the 16 sites studied. Highest populations and the most species were found in a grass community, but occurred in different months in each of the three years. Lowest populations were found in a Coleogyne community, and fewest species in an Artemisia- grass community.     

Relationship between environmental and vegetational parameters for understory and open-area communities

Ten individuals from each of four tree species were selected, and their associated understory and adjacent open-area communities were sampled for both environmental and vegetational parameters, including light intensity, pH, litter depth, soil depth, and percentages of exposed rock, litter cover, living cover, shrubs, forbs, grasses, and annuals. The four tree species were ponderosa pine, Rocky Mountain juniper, Gambel oak, and snowbrush ceanothus. The study site was in the lower Uinta Mountains about 10 miles east of Kamas, Utah. Correlations among the various biotic and abiotic parameters were examined. The interplay of these factors in differentiating the understory and open-area communities is discussed.       

Lichens of soil crust communities in the Intermountain Area of the western United States

Lichens are common components of microbiotic soil crusts. A total of 34 species from 17 genera are reported from soil crust communities throughout the Intermountain Area. Distribution of terricolous lichens is determined by various physical and biological factors: physical and chemical characteristics of the soil, moisture regimes, temperature, insolation, and development and composition of the vascular plant community. Some species demonstrate a broad ecological amplitude while others have a more restricted distribution. All growth forms are represented; however, the vast majority of soil crust lichens are squamulose (minutely foliose). Fruticose species are least abundant. In exposed, middle-elevation sites vagrant (detached) species are common. This paper describes and discusses terricolous lichen communities of desert habitats of the intermountain western United States. Effects of various human-related activities including grazing, wildfire, air pollution, and recreation vehicles on soil crust lichens are discussed. Gypsoplaca macrophylla (Zahlbr.) Timdal, a rare squamulose lichen which occurs on gypsifersous soils, was recently collected in Emery County, Utah, and is reported as new to the state.