Occurrence, persistence, and expansion of saltcedar ( Tamarix spp.) populations in the Great Plains of Montana

Saltcedar ( Tamarix spp.), a shrub native to Eurasia, is associated with major alterations to wetland and riparian systems in the southwestern United States. Since the 1960s saltcedar has been naturalized in northern states of the U.S. where its growth potential and impacts are not well known. Here, we describe the occurrence, age, size, and relative cover of saltcedar populations in several river basins in central eastern Montana, USA, to identify potential patterns of spread across the region and changes in individual populations as they age. Stands were aged according to the oldest saltcedar individuals and were sampled for dominant plant cover and soil properties. Multiple introductions appear to have occurred in Montana, with the oldest stands occurring on the Bighorn River in southern Montana. Saltcedar absolute and relative cover and stand area increased significantly with stand age, while native tree and shrub relative cover remained low across all stand ages. These results suggest that saltcedar stands establish where woody natives are not abundant and that they persist and expand over time. Although soil salinity remained constant, soil pH decreased with saltcedar stand age, indicating a possible effect of organic matter inputs. An analysis of annual wood increment of saltcedar and sandbar willow (a native with analogous growth form) stems along a latitudinal gradient showed that stem growth of both species did not differ significantly among regions. Stem growth decreased inversely with elevation for both species while growth responses to elevation did not differ between species. Our results show an increase in number of populations and continued viability of these populations. Mechanisms of saltcedar increases in this region are yet to be determined. Anthropogenic influences, such as saltcedar plantings, watershed alterations (e.g., river flow control), and habitat disturbances (e.g., cattle grazing or habitat clearing) may facilitate its spread in similar climates of the Great Plains.     

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.        

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.     

Comparative habitat and community relationships of Atriplex confertifolia and Sarcobatus vermiculatus in central Utah

Thirty-four study sites were established in shadscale ( Atriplex confertifolia [Torr. & Frem.] Wats.) and greasewood ( Sarcobatus vermiculatus [Hoov. Torr. in Emory) communities bordering Utah Lake in central Utah. Differences in species composition, vegetation, and soil characteristics were assessed. Significant differences in soil factors between the two communities were found for sand, calcium, manganese, zinc, and copper. Soluble salts and sodium concentrations were generally higher in the greasewood type, but differences were not significant. Major differences were found in understory species, with burr buttercup ( Ranunculus testiculatus Grantz) showing significantly greater cover in the shadscale community and cheatgrass ( Bromus tectorum L.) showing significantly greater cover in the greasewood community.     

Diseases associated with Juniperus osteosperma and a model for predicting their occurrence with environmental site factors

On 17 Utah juniper ( Juniperus osteosperma [Torrey] L.) sites studied in Utah, Gymnosporangium inconspicuum was the most common rust fungus, followed in frequency and severity by G. nelsoni, G. kernianum, and G. speciosum . The incidence of G. kernianum was correlated with moderate temperatures and greater than average precipitation. True mistletoe, Phoradendron juniperinum Engelm., was present on seven sites. Incidence of foliage diseases of the mold-mildew type was low on sites with low spring and summer temperatures and high on sites with high summer and fall precipitation. Wood rot was common, and incidence seemed to be correlated with low winter temperatures and low soil nitrate but not with annual precipitation. Needle blight, shoot dieback, and needle cast symptoms were common and considered of abiotic origin. Their nonparasitic nature was indicated by lack of association with pathogenic organisms and the positive correlation of their incidence with winter injury and summer drought factors. Needle blight was also positively correlated with high soil salinity but negatively with high soil calcium regardless of salinity. A nonparametric model was developed that accurately predicted the frequency of the mold-mildew type diseases of J. osteosperma based on measured environmental site factors.     

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.     

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.     

Habitat requirements for Erigeron kachinensis , a rare endemic of the Colorado Plateau

Erigeron kachinensis is a rare endemic of the Colorado Plateau in southeastern Utah. This perennial composite grows in small, isolated populations at seeps and alcoves arising along canyon walls in Cedar Mesa Sandstone substrates. Characteristics of six Erigeron kachinensis sites in Natural Bridges National Monument, San Juan County, Utah, were studied to determine habitat requirements for this species. Sites were analyzed with respect to geology, soil chemistry, physical properties, and vegetational characteristics. The alcoves studied were very saline, often with soil surfaces covered with a white crust of salt. Living cover was enhanced by perennially moist soils, diminished amounts of solar radiation, soil salinity, and above-average amounts of available soil phosphorus. Kachina daisy vegetative growth appears to be favored by these same abiotic factors. The most commonly associated plant species on E. kachinensis sites were Aquilegia micrantha, Calamagrostis scopulorum, Zigadenus vaginatus, and Erigeron kachinensis . These species and the daisy accounted for more than 75% of the total living cover in the alcoves studied. A principal components analysis procedure was developed for evaluating site suitability for Erigeron kachinensis . This daisy has been successfully introduced to a site selected using that model.     

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.     

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.     

Weed control and soil amendment effects on restoration plantings in an Oregon grassland

The restoration of perennial grasslands in western North America often depends on effective weed control. We took advantage of a grassland restoration site on the Nature Conservancy's Agate Desert Preserve in southern Oregon (TNC 1997), where 3 sites had been previously burned, mowed, or both. At these sites we carried out a series of controlled, replicated experiments designed to test the effectiveness of 3 weed control measures: (1) sawdust, (2) glyphosate herbicide, and (3) herbicide plus an alfalfa mulch. All plots were seeded with a mix of 3 native perennial grasses. The soils of the 3 areas differing in previous vegetation management were similar, with the exception of total available soil nitrogen, which was significantly lower in the 2 burned sites. The sawdust treatment reduced total available soil nitrogen, but only in the unburned site, and only in the first few months after application. In all 3 areas the alfalfa mulch significantly increased total available soil nitrogen. However, none of these soil nitrogen differences significantly affected the success of weeds or planted perennial grasses. The herbicide treatment reduced exotic annual grasses and forbs and greatly increased the success of native forbs and the planted perennial grasses. The herbicide increased both initial establishment of the native grasses and their absolute cover and biomass. These results suggest that neither nitrogen impoverishment nor nitrogen enrichment was a useful restoration technique at this site, but weed control by herbicides can be of considerable assistance in restoring native perennial grasses.     

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.     

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.     

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.     

Comparison of insects from burned and unburned areas after a range fire

Insect communities at recently burned and unburned sites in the Great Basin of northwestern Utah were studied by weekly sampling with pitfall and Malaise traps. More specimens were consistently collected at the burned site, although the numbers of species between the sites were about equal a month after the fire. Flying insects showing no preference for the sites were sciarids, phorids, and leafminer flies (all Diptera). Insects preferring the unburned site were mostly entomophagous flies such as pipunculids, chamaemyiids, and tachinids. Insects more common at the burned site were mosquitoes and phytophagous species of lygaeid bugs, leafhoppers, and moths. Seasonal trends in relative abundance of major families of flying insects are reported. Ground survivors included gryllacridids, carabids, tenebrionids, and ants. Silphids and buprestids immigrated into the burned area soon after the fire. Interrelationships between the burned area and the insect community are dicussed.     

Observations on Double-crested Cormorants ( Phalacrocorax auritus ) at sportfishing waters in southwestern Utah

Counts of Double-crested Cormorants ( Phalacrocorax auritus ) were made at 13 reservoirs and lakes in southwestern Utah during 1989-91 to determine current abundance of that species. Food habits of cormorants were studied at three of the reservoirs in 1989. Data were also collected on trout abundance during standardized gill-netting to make comparisons between cormorant numbers and trout abundance. Cormorants were observed at all waters studied except one and were generally most numerous during the spring as they migrated through the area. Estimated cormorant abundance ranged from 0 to 34 bird-days per ha and was highest at the larger, lower-elevation reservoirs. Cormorants were summer residents at several of the larger reservoirs and nested successfully at Piute Reservoir. Trout accounted for 24-81% of the diet of cormorants, with Utah chubs constituting most of the remainder of the diet. Estimates of the annual consumption of fish by cormorants ranged from 0 to 15.8 kg per ha. The index of trout abundance was inversely related to cormorant abundance ( P < .01) at the waters studied. Cormorants apparently have increased in numbers and extended their range in southwestern Utah during the past decade. This change may be the result of factors that have led to similar changes throughout North America as well as some factors unique to Utah. Methods to mitigate the impact of predation by piscivorous birds of sportfisheries are discussed. The Utah Division of Wildlife Resources has initiated a new management plan at Minersville Reservoir that incorporates piscivorous birds into sportfish management at that reservoir.     

Habitat manipulation for reestablishment of Utah prairie dogs in Capitol Reef National Park

Utah prairie dogs were transplanted onto the site of a former colony, located in Capitol Reef National Park, Utah. Shrubs on the site were significantly taller than those found on active colonies in similar habitat located on the Awapa Plateau. Therefore, the transplant site afforded a test of the hypothesis that shrub height is a major inhibitory factor affecting occupation of sites by prairie dogs. Four sites of 5 ha each were used. Vegetation treatments &mdash; rotobeating, railing, and 2,4 - D herbicide &mdash; were carried out on three of the sites and the fourth was used as a control. Shrub height and percent cover were significantly reduced on all three treatment sites. Posttreatment effects on the vegetation showed that the greatest percent moisture of the herbage was found on the railed site, followed by the herbicide, rotobeaten, and control sites. Measurements of the visual obstructions to prairie dogs showed that the rotobeaten site had the greatest visibility, followed by the railed, herbicide, and control sites. Prior to release of prairie dogs on the study area, 200 artificial burrows per treatment were dug, using a power auger. In early summer, 1979, 200 Utah prairie dogs were live - trapped near Loa, Utah. An equal number by sex and age class were released on each treatment. In 1979 a significantly higher number of animals reestablished on the rotobeaten site. In 1980 and 1981 the rotobeaten and railed sites had significantly higher prairie dog numbers than the other sites. Reproduction occurred on both the rotobeaten and railed sites in 1980 and 1981. Results indicated that, when transplanting animals onto sites of former colonies presently overgrown with shrubs, the chances of a successful transplant could be increased by first reducing shrub height and density.     

Habitat relationships of the blackbrush community ( Coleogyne ramosissima ) of southwestern Utah

Eight general study sites in the blackbrush ( Coleogyne ramosissima ) zone of southwestern Utah were examined. Soils data were gathered and plant cover was estimated. Shrubs were found to he positively correlated with shallow, sandy soil. Nonwoody plants were found to be positively correlated with deeper, silty soils. Cryptogamic soil crusts were positively correlated with silt and nitrogen in the soil and therefore may play a role in elevating soil fertility. Shrubs and grasses were negatively correlated. Management implications are discussed. &nbsp;&nbsp;&nbsp;     

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.     

Microbial spatial heterogeneity in microbiotic crusts in Colorado National Monument. II Bacteria

Microbial spatial heterogeneity and bacterial composition of homogeneous surface soils showing evident microbiotic crust development located under Utah juniper canopies in Colorado National Monument were studied. Four distinct homogeneous sampling sites positioned along a 12-m transect were compared on the basis of bacterial density and taxa composition. Bacterial densities showed a range differing by several orders of magnitude. In comparisons of adjacent soil samples or samples taken from two different sampling sites within close proximity, adjacent samples showed no more similarity to each other on the basis of bacterial density or taxa composition than did more widely separated samples. The bacterial composition of these soils included members of the genera Bacillus , Micrococcus , and Arthrobacter . Actinomycetes were also prevalent.