Jack D. Brotherson

Effects of long-term grazing on cryptogam crust cover in Navajo National Monument, Arizona.

The effects of long-term grazing (40 years) on cryptogamic crusts of Navajo National Monument were investigated. Both vascular and nonvascular communities were heavily impacted with the cryptogamic community showing the greatest reduction in cover. Lichens and mosses were the most damaged, while the algae were much more tolerant. Individual cryptogamspeeies were affected in similar patterns with all identifuble species showing reduced cover. Vascuhr plant species were also affected with grassesshowing the greatest reduction under grazing pressure. Throughout desert systems of western North America there is scant ground cover and often extensive open areas between the plants. In such open areas, soils are exposed to powerful erosive impacts. When soils are unprotected, erosion can be extensive and soil losses can be great. Of primary importance in the protection of desert soils are communities of nonvascular cryptogamic plants that grow upon or immediately beneath the soil surface. When well established and undisturbed such plants form a crust which plays an important role in soil stabilization (Fletcher and Martin 1948; Kleiner and Harper 1972, 1977; Loope and Gifford 1972; Anderson et al. 1982a, 1982b). Algae are the primary components of these crusts but they are often accompanied by lichens and mosses (Anderson and Rushforth 1977, Kleiner and Harper 1972). Algae are the most effective in binding the soil particles (Anantani and Marathe 1974, Anderson and Rushforth 1976). Where cryptogam crusts are well developed the soil surface is almost always highly stable. Research has been done on several aspects of the biology of soil crusts and cryptogamic communities. Ecological relationships have been studied by Anderson et al. (1982a) and Anderson et al. (1982b). Species composition and taxonomic relationships of crusts were studied by Anderson and Rushforth (1976). The role of such crusts in nitrogen fixation was studied by Rychert and Skujins (1974) and their effects on infiltrationand sedimentation by Loope and Gifford (1972). However, much is yet to be learned about the role of these crusts in desert ecosystems. The Navajo National Monument boundary (fenceline) provided an excellent opportunity to evaluate the effects of grazing on the cryptogamic soil crusts of the pinyon-juniper zone in northeastern Arizona. The objective of this study was to evaluate the effects of long-term grazing (40 years) on the cryptogamic soil cover of the pinyon-juniper zone in northern Arizona (Navajo National Monument).

The effects of fire on the blackbrush (Coleogyne ramosissima) community of southwestern Utah.

Eight general study sites were examined in the blackbrush (Coleogyne ramosissima) zone of southwestern Utah in order to assess the impact of burning. All sites had been burned. Age since burning varied from 1 to 37 years. Plots were placed in bumed areas with plots in adjacent unburned areas serving as controls. Sites were similar enough that definite trends were distinguishable despite between site variation. Recently burned areas were dominated by forbs, middle aged burns were dominated by grasses, and the oldest burns had reverted back to shrub dominance. Cryptogamic soils crusts were severely affected by burning and showed no signs of recovery after 19.5 years. Blackbrush was also severely affected and showed no signs of recovery after 37 years. Lack of recovery by blackbrush may be due to its paleoendemic nature. Future burning of stands of blackbrush in southwestern Utah is not recommended.

The effects of dissolved heavy metals on attached diatoms in the Uintah Basin of Utah, U.S.A.

The relationships of diatom species to dissolved heavy metals in the streams of the Uintah Basin of Utah were studied through four seasons of 1977–1978. Niche center gradient analysis, cluster analysis and correlation analysis were performed.Achnanthes minutissima, Cyclotella meneghiniana, Cymbella minuta, Gomphonema parvulum, Navicula secreta var.apiculata, Nitzschia frustulum, Nitzschia frustulum var.perminuta, Nitzschia frustulum var.perpusilla, Nitzschia palea, andSynedra ulna appear to be indicator species of high or low heavy metal concentrations. Several other species also showed meaningful relationships to high or low heavy metal concentrations.

Algal response to a thermal effluent: study of a power station on the Provo River, Utah, USA

The effect of a thermal effluent on the attached algae of the Provo River, Utah, USA, was studied from 1975 to 1977. Data for macroscopic and microscopic algae were collected and analyzed. Diatoms, Cladophora glomerata, and Hydrurus foetidus dominated the flora. The thermal effluent significantly affected the algal flora in a section of river 100 to 135 meters long immediately below the discharge point. Cladophora growth was increased and Hydrurus was absent in this area. In addition, diatom production was often higher and diversity lower than in the rest of the river. Community structure was unique from all other adjacent areas. Small temperature increases which occured as effluent and river waters mixed farther downstream were apparently not as important to the algal flora as other environmental factors.

Seasonal variation of monoterpenoids in big sagebrush (Artemisia tridentata).

Monthly monoterpenoid content was determined for 16 big sagebrush (Artemisia trhhtata) plants grown on a uniform garden. These 16 plants were selected at random from 4 accessions of basin big sagebrush (A.1. ssp. tridentata)-4 plants per accession. A composite sample wn taken for a fifth accession of mountain big sagebrush (A.t. vasqana). Monoterpenoid content varied seasonally with the lowest content occurring during May (0.97% of dry matter). Highest monoterpenoid content occurred during July (4.18 %) followed by August (3.36%) and September (2.73%). Dove Creek (2.61% of dry matter)ad Marysvale (2.64%) basin big sagebrush accessions contained significantly higher pooled levels of monoterpenoids than the Indhutola (1.73%) and Loa (1.55%) big sagebrush accessions. The composite samples of the Indian Peaks mountain big sagebrush accession, an accession significantly preferred over tbe Marysvale and Loa accessions, contained an overall monoterpenoid level of 282%. Adverse relationships between monoterpenoid content and the consumption of big sagebrush by wintering mule deer seem weak. Monoterpenoids, also called “volatile or essential oils,” have been implicated as having an adverse effect on the preference of wintering mule deer (Odocoileus hemionus) for accessions of big sagebrush (Artemisia tridentata) (Nagy and Regelin 1977, Nagy 1979). This means that wintering mule deer would prefer accessions or plants of big sagebrush with the lowest monoterpenoid content. In general, wintering mule deer in Utah and Oregon prefer subspecies vaseyana over subspecies tridentata and wyomingensis (Hanks et al. 1973, McArthur et al. 1979, Sheehy and Winward I98 1, Welch et al. 198 1). Welch and McArthur (1981) reported that in a uniform garden the preferred subspecies vaseyana contained significantly higher winter levels of monoterpenoids than subspecies tridentata and wyomingensis. This conflicts with the idea that monoterpenoids have an adverse effect on the preference of wintering mule deer for big sagebrush. The use of big sagebrush by mule deer is cyclic, Mule deer start consuming significant levels of big sagebrush in the mid to late fall period. Peak big sagebrush consumption occurs during winter and then declines to almost zero in mid to late spring (Leach 1956, Kufeld et al. 1973, Tueller 1979, Medin 1980, Welch et al. 1981). Leach (1956), Welch and Andrus (1977), Medin (1980), and Medin and Anderson (I 979) noted that other types of forages were almost continuously available for wintering mule deer consumption. Deer did not have to consume big sagebrush. Tueller (1979), however, reported a lack of choice among forages for the deer units he studied. If monoterpenoids negatively influence big sagebrush consumption, then it would be expected that maximum consumption (winter) should occur during periods of lowest monoterpenoid content. Also, among accessions of known preferences (Welch et al. 1981), the most preferred accessions should contain the least amount of monoterpenoids. Therefore, we undertook this study to Authors are graduate research assistant, Range Science Department, Brigham Young University, Provo. Utah 84602, principal plant physiologist, Intermountain Forest and Range Experiment Station, Shrub Sciences Laboratory, Provo, Utah 8460 I: and associate wofessor of range science. Range Science Department. Brigham Young University, Piovo, Utah 841#2. Manuscript received May IO, 1982. 492 determine the seasonal variation of monoterpenoid content in big sagebrush in an attempt to determine influence of monoterpenoids on the cyclic use of big sagebrush. We used accessions of known preference to mule deer to facilitate interpretations. Materials and Methods From a uniform shrub garden near Helper, Utah, 4accessions of basin big sagebrush (A, tridentata ssp. tridentata) were chosen to determine the seasonal variation of monoterpenoids. These 4 accessions were Dove Creek, Marysvale, lndianola, and Loa. Each accession was represented by 4 plants selected at random. The same 4 plants per accession were used throughout the study. An accession of mountain big sagebrush (A. tridentata ssp. vaseyana) from the Indian Peaks area of Utah was selected because of the higher preference that deer have for this accession. Because of smaller plant size and higher utilization, composite samples of the Indian Peaks accession were taken to ensure enough tissue for the study. Wild mule deer feed in this garden from about November to April. The preference for these 5 accessions is known (Scholl et al. 1977, Welch and McArthur 1979, Welch et al. 1981). Vegetative samples of current-year leaves and stems were collected randomly over the entire crown of each ssp. tridentata plant. Collections were made during the middle of each month (January through November 1980). After the November collection, some of the plants lacked terminal buds; therefore, further sampling would not have been the same as in the preceding sampling periods. All samples were collected within a 90-minute period (lO:OO-II:30 a.m.) (Nicholas 1973). Tissue (leaves and stems) collected from a given ssp. tridentata plant was placed in a paper bag and frozen on site with dry ice. For mountain big sagebrush, the Indian Peaks accession, 4 vegetative shoots of current year’s growth were removed from each of the plants in the Indian Peaks row, pooled in a paper bag, and frozen. Samples were transported in a cooler to laboratory. At the laboratory the samples were placed in plastic bags, tied, and stored in a freezer (-35” C) until needed for grinding and extraction. Samples were ground with liquid nitrogen using a motorized steel mortar and pestle. Extracting and analyzing for monoterpenoids has been described by Welch and McArthur (1981). The data for this study are expressed on a percent dry matter basis. A randomized analysis of variance was used to detect signiticance among accessions of big sagebrush and among months. Tukey’s multiple-range test (a=O.OS%) was used todetect signifiance among treatment means. Data were tranformed to arcsin. (The Indian Peak accession of mountain big sagebrush was not included in the analysis of variance.)

Stem-diameter age relationships of Tamarix ramosissima in central Utah.

The stem-diameter age relationships of salt cedar from 15 study sites in central Utah were investigated. Age prediction equations were generated and found significant (p<.OOl). Within restricted geographic areas the stem ages of salt cedar could be estimated with fair reliability, but with substantial geographic separation results were less accurate. The impact of salt cedar invasion over prolonged periods of time was also assessed. Results indicated that the longer the community has been occupied by salt cedar the more xeric the habitat becomes. Saltcedar (Tamarix ramosissima) is a vigorous invader of pastures, moist lowlands and stream banks throughout much of the southwestern United States (Tomanek and Ziegler 1960). It is also found in dense thickets through much of central Utah (Christensen 1962). Saltcedar has the highest transpiration rates of any North American phreatophyte (Kiegler 1968) and can depress the water table often by as much as 1.2 to 2.1 m/ yr (Horton 1964). Although studies have been made of the distribution and naturalization of saltcedar (Christensen 1962, and Horton 1964), and of its ecology and habitat requirements (Tomanek and Ziegler 1960, Carman 1979), much less is known of its stem diameter: age relationship and/or population dynamics. Studies of the growth rings of trees have been used extensively for dating (Douglas 1935, Glock 1937) reconstructing past climates (Fruits 1971, Harper 1979, Schulman 1956, Stockton and Meko 1975) and interpretation of successional dynamics (Burkhardt and Tisdale 1969, Barney 1972). Data on shrubs are relatively rare (Ferguson 1958, 1959; Ferguson and Humphrey 1959) but should be equally valuable. Brotherson et al. (1980b) included saltcedar in their study of the size and age relations of 8 major tree species of Navajo National Monument, Ariz. The present study considers the stem diameterage relationship of saltcedar from 15 sites in central Utah and compares these relationships with the Arizona saltcedar population.

Pinyon-juniper chaining and seeding for big game in central Utah.

Vegetation and soils were evaluated on 5 different-aged, mechanically treated and seeded pinyon-juniper sites and compared to adjacent untreated areas. Plant cover was significantly changed after treatment: trees were reduced from 26 to 6% total ground cover; shrubs were increased from 2 to 8% ground cover; and herbaceous plants increased from 2 to 13% ground cover. Annuals and perennial forbs were 75% of the total plant cover on the 2-year-old site, perennial grasses and shrubs dominated the plant cover (52 to 83%) on three, 14- to 20-year-old sites, while shrubs and trees combined for 94% of the plant cover on the 24-year-old site. Two Agropyron grass species showed good establishment and persistence after seeding. Seeded forbs contributed about 5% of the total plant cover on the 2-year-old treated site and they declined on older treated sites. Seeding of shrubs was only successful on sites where the shrub species was already present in the understory naturally. Seeding of nonnative shrub seed did not produce stands. Even though tree cover was reduced after treatment, total tree density was not. Shrub density increased from an average of 800 plants/ha on untreated areas to 2,750 plants/ha on treated areas. Juniper mortality during mechanical treatment varied from 60 to 91% and was related to the percentage of trees estimated to be 60+ years old (r = 0.97) and with the number of trees greater than 5 cm in stem diameter (r = 0.71) on the adjacent untreated sites. Big game pellet group counts were not different between untreated and treated sites, suggesting that big game make use of these treated areas because of increased forage and browse and in spite of reduced security cover.

The effects of selected physical and chemical factors on attached diatoms in the Uintah Basin of Utah, U.S.A.

The relationships of diatom species to selected physical and chemical parameters in the streams of the Uintah Basin of Utah were studied through four seasons of 1977–1978. Niche center gradient analysis, cluster analysis and correlation analysis were performed.Achnanthes minutissima, Cyclotella meneghiniana, Cymbella minuta var.latens, Fragilaria capucina, andNavicula secreta var.apiculata appear to be indicator species of high or low levels of certain water quality parameters. Several other species also showed meaningful relationships to selected physical and chemical parameters.

Microhabitat relationships of six major shrubs in Navajo National Monument, Arizona.

Six shrub species were studied to determine their microhabitat relationships as well as their effect on the immediate environment. Analysis of site characteristics and mineral composition of soils in open areas adjacent to shrubs and beneath shrubs allowed for comparison of the different habitats following shrub establishment. Soil pH differs beneath the various shrubs and all six species tended to create more alkaline soils beneath their canopy. All species showed increased soil salinity beneath their canopy. However, the concentration of total soluble salts in the soil surface beneath the shrubs varied with the species and was highest beneath fourwing saltbush. Significant increases in the concentration of magnesium and potassium ions beneath shrubs were observed. Nitrogen and phosphorus were also found in greater concentration beneath the shrub canopy. Soil depth differed beneath the shrub species, with sagebrush and fourwing saltbush growing on the deeper more highly developed types. There was a positive relationship between the presence of shrubs and the depth of the soil profile. It has long been known that shrubs influence the soil characteristics beneath their canopy (Fireman and Hayward 1952). Studies done in the last decade show that shrubs influence both the horizontal and vertical patterning of soil chemicals (Charley and West 1975). Sharma and Tongway (1973) studied the effects of two species of saltbush (Atriplex nummularia and Atriplex vesicaria) on soil salinity and related properties. They recognized an accumulation zone beneath the shrubs, a zone of compensation where leaching of minerals replaced those absorbed, and ‘a depletion zone from which mineral absorption exceeded the rate of replacement. Salt accumulation under shrubs, therefore, represents a redistribution of salts from peripheral regions of root activity (Charley and West 1975). Plants employ several “strategies” for the removal of mineral wastes. Leaching of minerals from leaves is accomplished when the solution of the leaf surface connects with that of the intercellular spaces of the mesophyll and ions are lost by diffusion. Salts are also excreted with the aid of salt glands, as is the case with many Atriplex species. Salts are also concentrated in the extracellular spaces of leaves during the process of transpiration, thus accumulating minerals in leaves. Leaf fall subsequently serves as a mechanism for the elimination of mineral wastes (Epstein 1972). Charley and West (1975) used the distributional patterns of carbon and nitrogen under and between shrubs as a measure of

Lichen Community Structure in Zion National Park

The saxicolous and corticolous lichen communities in Zion National Park were surveyed. A total of six sampling sites were established in Zion Canyon with a seventh site in Coalpits Wash, 22 km south of Zion National Park Visitor Center. Individual trees at each site were selected for lichen sampling using the quarter method. Aspect-induced differences in the distribution of corticolous species were determined by examining quadrats on the north, south, east and west exposures of each individual tree. Rock substrates at each site were selected on the basis of overall size and exposure. Frequency and density of lichen species on all substrates were determined using a 2 by 100 cm quadrat with ten equal subquadrats. Data analyses indicated that the lichen floras on each substrate were unique. Of the saxicolous substrates sampled, species diversity was highest on sandstone boulders. Lichen floras on Populus fremontii, Quercus gambelii and Acer grandidentatum showed the greatest diversity of the corticolous substrates. The lichen flora of Zion Canyon includes a relatively high percentage offoliose and fruticose lichen species. This is especially evident when this flora is compared with floras of other arid environments. This phenomenon is likely attributable to the unique microclimatic features of the canyon. The saxicolous and corticolous lichen communities of Intermountain Western North America are widespread, rich in species, and well developed (Darrow 1950; Nash 1974; Nebeker 1981). They are among the least disturbed natural plant communities of this region because they occur on substrates generally not directly impacted by human activity. In most cases, the only significant direct influence on these communities is from atmospheric pollution. The effects of airborne contaminants on individual lichen species as well as lichen community structure are various. The response of a particular lichen species to air pollutants is determined by a number of factors. These may include: substrate type (Laundon 1967); life form (Gilbert 1970); aspect (Hoffman 1974); density and composition of the vascular plant community; topographical features of the habitat (McCarthy 1978); and rainfall and humidity levels (Marsh & Nash 1979). Changes in community structure caused by air pollution are evidenced by the elimination of sensitive species with a general trend 007-2745/82/185-192