Records of exotic fishes from Idaho and Wyoming

One exotic poeciliid ( Xiphophorus helleri ) and two cichlids ( Cichlasoma nigrofasciatum and Tilapia mossambica ) are recorded as recently established in thermal springs and their outflows in southern Idaho. Misgurnus anguillicaudatus was collected and is considered as established in the Boise River system. Poecilia mexicana and juvenile hybrid tilapias are recorded from the Bruneau River at Bruneau Hot Springs, Idaho. A reproducing population of X. helleri was found in a spring within the boundaries of Grand Teton National Park, Wyoming. Poecilia reticulata , previously reported from one spring each in Idaho and Wyoming, is recorded from a second spring outflow in Idaho.     

Dispersal of sagebrush-steppe seeds by the western harvester ant ( Pogonomyrmex occidentalis )

Like many seed-harvesting ants, the western harvester ant ( Pogonomyrmex occidentalis ) can act as both a predator and a seed disperser. Dispersal results when seeds are dropped en route to the nest, are left in nest granaries when colonies die or are abandoned, or are removed from granaries and discarded in nest middens. This study examined the density and species identity of seeds discarded in harvester ant nest middens and compared them with those found in nearby soils. Nineteen species of seeds were recovered from middens, compared with 13 species in 5-m reference areas and 9 species in adjacent disk areas. Total density of sound seeds was nearly 3 times higher in middens than at 5 m from the nest and nearly 50 times higher than in disk soils. Moreover, 4 of the 6 most common species overall were significantly more abundant in middens. One species, Munro globemallow ( Sphaeralcea munroana ), was recovered from nearly 50% of middens but was not found in the other 2 areas. These findings suggest that the western harvester ant is a potentially important disperser of some sagebrush-steppe plant species.     

Effectiveness of the seed wing of Pinus flexilis in wind dispersal

Limber pine ( Pinus flexilis James) seeds are usually wingless but occasionally have short, stubby wings. To determine the effectiveness of these wings in slowing seed descent, rates of fall were determined before and after wing removal. A similar experiment was conducted with seeds of Himalayan blue pine ( P. griffithii McClelland), a white pine with typically long seed wings. The short wings of limber pine seeds were found to influence rate of seed fall far less than the wings of Himalayan blue pine. This is consistent with evidence suggesting that limber pine seeds are not effectively dispersed by wind but are dependent for dispersal on Clark's Nutcracker ( Nucifraga columbiana ).        

Seasonal occurrence and adaptation of the exotic Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae) in Italy

Alien insects usually adapt their phenology and their needs to the environment into which they are introduced. During 2010, the red gum lerp psyllid, Glycaspis brimblecombei, was accidentally introduced into Italy, becoming an invasive pest of Eucalyptus L’Hér. Eucalypts are very common in Italy as ornamental and forest species. The seasonal adaptation of the psyllid was studied at three field sites. G. brimblecombei showed a seasonal population dynamic, suggesting that many generations occur during the year and the species overwinters in all stages without diapause. The population size in the new area of colonization is affected by low winter temperatures, but also by high temperatures in the absence of rainfall. In Lazio, the specific parasitoid Psyllaephagus bliteus was collected for the first time.     

Effects of browsing by native ungulates on the shrubs in big sagebrush communities in Yellowstone National Park

The effects of elk ( Cervus elaphus ), pronghorn ( Antilocapra americana ), and mule deer ( Odocoileus hemionus ) browsing on shrubs in big sagebrush ( Artemisia tridentata ) communities were monitored over a 31-year period in Yellowstone National Park. Ungulates were restricting Wyoming big sagebrush (spp. wyomingensis ) heights, size, and recruitment on the lower-elevation stratum only, while no such suppression was observed on the high-elevation stratum. Parallel increases in mountain big sagebrush (spp. vaseyana ) densities and cover occurred over the study period on both browsed and unbrowsed sites at the higher-elevation stratum, although big sagebrush, green rabbitbrush ( Chrysothamnus viscidiflorus ), and horsebrush ( Tetradymia canescens ) were slightly taller and crown sizes were slightly larger on unbrowsed than browsed sites. Wyoming big sagebrush utilization (percent leader use) was eight times higher (￣ x = 87 ± 7.2% by pronghorns, mule deer, and elk) on the low-elevation winter ranges stratum (the Boundary Line Area [BLA] portion of the winter range), while mostly mountain big sagebrush with leader use averaged only 11 ± 4.1% (nearly all by elk) on the high-elevation range stratum. In addition, annual aboveground biomass production of big sagebrush did not differ between browsed and unbrowsed study sites on the high-elevation stratum of the winter range. Population turnover was higher on browsed plots versus unbrowsed plots. No difference was observed in percent dieback of big sagebrush adult plants between browsed and unbrowsed plots at the higher stratum. Browsing did not influence the number of leaves or seedstalks per plant ( P > .05), but leaves averaged 45% longer and seedstalks 42% longer on browsed big sagebrush. Ungulate browsing, however, apparently suppressed production, germination, and survival of Wyoming big sagebrush on the low-elevation stratum. Numbers of Wyoming big sagebrush declined 43% and cover declined 29%, 1957-1990, on browsed sites on the BLA. Annual biomass production on browsed sites at the low-elevation stratum was only 6-35% that of unbrowsed sites, and big sagebrush recruitment was less on browsed sites. Percent leader use of big sagebrush did not differ between the period of ungulate reductions, 1962-1969, and the 1980s on the lower stratum (￣ x = 87% leader use), but utilization was less on higher portions of the winter range during the period of elk reductions (￣ x = 2%) than during the 1980s following cessation of elk controls (￣ x = 11%).     

Alpine and subalpine wetland plant communities of the Uinta Mountains, Utah

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Seven wetland areas in the subalpine and alpine regions of the Uinta Mountains are described. Most areas have a mosaic vegetation structure, comprised of several patches that are usually sharply demarcated from one another. Each patch has a distinct species composition, usually with only one or two species. Water level is associated with some of the vegetation patterns found in these sites. Standing crop varied from 28 to 360 g/m 2 . Sites show considerable variation in standing crop that could not be explained by elevation differences between sites. Sites with water flowing over them have substantially greater standing crops than sites where water stagnates. Seasonal patterns in shoot density and standing crop indicate one late summer peak in standing crop and little recruitment of shoots over the summer. On stagnant sites, the average stem weight shows a strong relationship to stem density. This pattern did not appear to be caused by thinning mortality and did not follow a “3/2 power law” pattern.       

Desiccation sensitivity and heat tolerance of Prunus ilicifolia seeds dispersed by American black bears ( Ursus americanus )

Carnivore consumption of fruit is a principle means by which many fleshy-fruited plant species achieve long-distance seed dispersal. We examined carnivore dispersal of hollyleaf cherry ( Prunus ilicifolia ) seeds, specifically assessing the survival, desiccation sensitivity, and germination of seeds found in bear scats. Studies were conducted both in the laboratory and in 2 burn areas in Los Padres National Forest, California. Bear scats containing P. ilicifolia seeds were collected in burned and unburned chaparral. We counted seeds in each scat and noted whether endocarps had tooth punctures or rattled audibly when shaken. For comparative germination trials, we also collected fruits and seeds directly from mature shrubs. In the laboratory, following a cold-moist stratification period, seeds were assessed for germinability. In the field, we compared desiccation rates and germinability of seeds from bear scats and freshly collected seeds. We compared rates of moisture loss and germination for seeds subjected to several different conditions, including 25 °C (room temperature), 30 °C and 65 °C (in the lab), and placement on exposed soil in a burn area (in the field), where midday temperatures were approximately 45 °C but likely much higher by late afternoon. Prunus ilicifolia seeds collected from bear scats were largely undamaged; the vast majority of these seeds germinated. In some cases, germination rate was higher for seeds from scats than for seeds from intact fruits. Several results indicate that desiccation is an important cause of reduced germinability. First, seeds that rattled audibly germinated poorly; and the louder the rattle, the lower the germination percentage. Second, seeds (both fresh and those from bear scats) placed in the field under protective screens had greatly reduced levels of germination (an 84% decline) after only 7 days. Third, seeds dried in the lab, even at relatively moderate temperatures, showed a decline in germination with seed moisture loss. The addition of high temperatures accelerated this decline in germination. We discuss the relevance of heat and desiccation sensitivity of seeds dispersed by bears to successful seed germination in burned and late-seral mesic and xeric chaparral. El consumo de fruta por carnívoros es uno de los principales medios por los que muchas especies de plantas de frutos carnosos logran dispersar sus semillas a través largas distancias. Examinamos la dispersión por carnívoros de las semillas del islay ( Prunus ilicifolia ), un arbusto del chaparral, evaluando concretamente la supervivencia, la sensibilidad a la desecación y la germinación de semillas encontradas en las heces de oso. Estos estudios se llevaron a cabo tanto en el laboratorio como en dos áreas quemadas en Los Padres National Forest, California. Se colectaron heces de oso que contenían semillas de P. ilicifolia en el chaparral quemado y en el no quemado. Contamos las semillas en cada bola fecal y notamos si los endocarpios tenían marcas de dientes y si vibraban audiblemente al agitarse. Para llevar a cabo pruebas comparativas de germinación, también colectamos frutos y semillas directamente de los arbustos maduros. En el laboratorio, después de un período de estratificación fría-húmeda, evaluamos la capacidad de germinación de las semillas. En el campo, comparamos las tasas de desecación y de germinación de semillas de las heces de oso con aquellas de semillas colectadas directamente de los arbustos. Se compararon las tasas de pérdida de humedad y germinación de las semillas sujetas a diversas condiciones, entre ellas 25 °C (temperatura ambiente), 30 °C y 65 °C en el laboratorio, y en el campo sobre suelo expuesto en un área quemada, donde la temperatura al mediodía era ~45 °C pero probablemente mucho más alta por la tarde. En general, las semillas de P. ilicifolia colectadas en las heces de oso no estaban dañadas; la gran mayoría de estas semillas germinaron; en algunos casos la tasa de germinación fue más alta que la de frutos intactos. Varios resultados indicaron que la desecación es una causa importante de la reducción en la capacidad de germinación. Primero, las semillas que vibraban audiblemente germinaron poco, y cuanto más fuerte el sonido, menor la germinación. Segundo, las semillas (tanto las frescas como las colectadas de heces de oso) colocadas en el campo bajo una malla protectora exhibieron niveles de germinación muy reducidos (una disminución del 84%) después de sólo siete días. Tercero, la germinación de las semillas desecadas en el laboratorio, incluso a temperaturas relativamente moderadas, disminuyó con la pérdida de humedad de las semillas. Temperaturas más altas aceleraron esta disminución en la germinación. Discutimos la importancia de la sensibilidad al calor y a la desecación en las semillas dispersadas por los osos para la germinación exitosa en el chaparral mésico y árido, tanto en el chaparral recién quemado como en el que está en las etapas finales de sucesión.     

Elemental compartmentalization in seeds of Atriplex triangularis and Atriplex confertifolia

Seeds of two halophytes, Atriplex triangularis, which grows in a mesic saline marsh environment, and Atriplex confertifolia, which grows in a xeric desert environment, were analyzed by energy-dispersive X-ray microanalysis for the distribution of elements. The highest concentration of sodium, chlorine, potassium, and calcium was present in seed coats of A. triangularis. All of the elements detected were at low concentrations in the endosperm. Embryos contained the highest amount of phosphorus that is probably associated with organophosphate compounds. Potassium was also high in embryos. The total amount of elements in all regions of A. confertifolia was low as compared to A. triangularis. In a similar pattern sodium, chlorine, potassium, and calcium were the highest in seed coats of A. confertifolia. Elemental concentration was also low in the endosperm. Likewise, the phosphorus level was the highest in the embryo. The results support the concept of elemental compartmentalization in seeds of these halophytes.     

Classification and ordination of Coleogyne communities in southern Nevada

Woody plant community composition was analyzed throughout the range of Coleogyne ramosissima in the Spring and Sheep Mountain ranges of southern Nevada. The lower Coleogyne elevational boundary was analyzed in detail in Lucky Strike Canyon, on the eastern edge of the Spring Mountains. TWINSPAN (2-way indicator species analysis) identified 4 primary species and stand groups from the 2 mountain ranges (extensive survey). Analysis of DECORANA (detrended correspondence analysis) results indicated that elevation and soil depth were the environmental factors most significantly associated with distribution of species and stand groups in the extensive survey. Elevation was the only significant physical factor associated with distribution of species and stand groups in the intensive survey. Five vegetation zones form the 2 mountain ranges were identified based on their dominant species in 15 extensive transects. Coleogyne were subdivided into pure stands and upper and lower ecotones for further investigation of species distribution and environmental factors. Selected environmental factors appear to play an important role in structuring the Mojave Desert vegetation zones in southern Nevada.     

Biotic and abiotic factors influencing the distribution of Coleogyne communities in southern Nevada

Woody plant community composition was analyzed throughout the range of Coleogyne ramosissima in the Spring and Sheep Mountain ranges of southern Nevada. The lower Coleogyne elevational boundary was analyzed in detail in Lucky Strike Canyon, on the eastern edge of the Spring Mountains. TWINSPAN (2-way indicator species analysis) identified 4 primary species and stand groups from the 2 mountain ranges (extensive survey). Analysis of DECORANA (detrended correspondence analysis) results indicated that elevation and soil depth were the environmental factors most significantly associated with distribution of species and stand groups in the extensive survey. Elevation was the only significant physical factor associated with distribution of species and stand groups in the intensive survey. Five vegetation zones form the 2 mountain ranges were identified based on their dominant species in 15 extensive transects. Coleogyne were subdivided into pure stands and upper and lower ecotones for further investigation of species distribution and environmental factors. Selected environmental factors appear to play an important role in structuring the Mojave Desert vegetation zones in southern Nevada.     

Flood frequency and the assemblage of dispersal types in hanging gardens of the Narrows, Zion National Park, Utah

Hanging gardens of the Narrows, Zion National Park, Utah, are plant communities growing at permanent seeps on the canyon walls. The gardens are isolated from each other and from other plant communities by vertical expanses of sandstone. Gardens consist mostly of herbaceous species less than 1 m tall. Though not individually species-rich, the hanging gardens are diverse as a group, and very dissimilar. This study considers two explanations of the heterogeneous distribution of species in hanging gardens. The assemblages of dispersal types in gardens of different spatial attributes and disturbance frequencies are examined. The G H statistic, a log likelihood ratio test, analyzes the incidence of dispersal types among classes of three spatial and two disturbance variables. The disturbance variables of expected flood frequency and soil depth segregate dispersal types; and the spatial variables of area, distance to possible seed sources, and relative isolation do not. Ferns and mosses, dispersing through spores, dominate a heterogeneous fugitive guild in the flood-prone gardens. Infrequently flooded gardens support more large-seeded species.     

Role of post-Pleistocene dispersal in determining the modern distribution of Abert's squirrel

Abert's squirrel is a forest-dwelling mammal, dependent upon ponderosa pine, that now ranges from southern Wyoming to northern Mexico. During the late Pleistocene, ponderosa pine and this squirrel occurred no further north than central Arizona and New Mexico. In consequence, the present range of the squirrel north of the 36thparallel must have been the result of post-Pleistocene (Holocene) dispersal. If such dispersal took place after the fragmentation of the northern montane conifer forest, at least some leakage across barriers of unsuitable (non-ponderosa pine) habitat must have occurred. Dispersal following transplanting "experiments" has shown that such barriers can be crossed; other evidence is provided that suggests this may occur sufficiently often to produce significant changes in distribution within short periods of time. Thus, explanations for the distribution of Abert's squirrel, based only on historical legacy and local extinctions, are found to be insufficient. An alternative explanation is proposed in which post-Pleistocene dispersal also plays an important role.     

Insect communities and faunas of a Rocky Mountain subalpine sere

Insect faunas and communities are characterized for herbaceous and tree canopy layers in meadow, aspen, and spruce/fir stages of a northern Utah sere. A greater percentage of species were in Thysanoptera in both aspen strata, and a greater percentage of individuals were in Lepidoptera in aspen canopy. Our sites were quite similar to a wide variety of other terrestrial sites in their distribution of species or individuals among orders or metamorphosis categories. Insects/m 2 peaked in the aspen stage, but declined in the herbaceous layer with succession. Insects/plant biomass in the herbaceous layer increased with succession. Insects/m 2 and insects/foliar biomass were higher in aspen canopies than in conifer canopies. Insect species/m 2 peaked in the aspen stage. This statistic was comparable in meadow and aspen understory, and lower in conifer understory. Insects/m 2 in the tree canopies were similar to the values in their respective understories. Insect species/plant biomass increased in the herbaceous layer with succession, but decreased in tree canopies with succession. Species evenness in both strata increased with succession. Adult body length was greatest for meadow species, least for conifer species. Adult body length per individual was greatest in aspen. Life cycle complexity was greatest in aspen. Insects on trees were more likely to have complex life cycles than those on herbs.         

Effects of land clearing on bordering winter annual populations in the Mohave Desert

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Construction of a 10-MWe solar thermal power plant in Daggett, California, involved clearing and leveling 53 ha of desert land. Transient offsite effects of this construction were apparent as a reduced density of annual plants within 100 m downwind of the edge of the cleared area. Schismus arabicus populations recovered within four years, but Erodium cicutarium populations did not. The effects appeared to be related more to an interaction of seed-dispersal mechanisms with the large, open space than to the obvious sand movement and deposition associated with the clearing operations.     

Seed banks of Bromus tectorum -dominated communities in the Great Basin

We seeded Agropyron cristatum and 16 native Great Basin perennial species on Bromus tectorum -dominated sites to compare temporal patterns of seedling emergence and early survival among species. To indicate variability between sites and between years, plots were planted on 2 sites in western Utah in autumn 1994, and plantings were repeated near 1 site in autumn 1995. Two sites included burned and unburned seedbed treatments. We monitored seedling emergence and survival from early winter until July of the 1st year. Four seasonal patterns of emergence were evident, indicating considerable potential for different seasonal patterns of precipitation to favor recruitment of difference species. Emergence of all shrubs, except Ephedra nevadensis , began in February and essentially ended by April. Seedlings of Ephedra nevadensis and of the grasses Agropyron and Pseudoroegneria spicata emerged over an extended period from February through June. Most other grasses and the 2 forbs began emerging in April and continued into June. Pleuraphis jamesii emergence did not begin until May. Although many seedlings of the 3 chenopod shrubs emerged, none survived, suggesting their episodic recruitment is more a function of survival than of emergence. Survival of 2 Chrysothamnus species was also low. Pseudoroegneria and Agropyron had the highest numbers of seedlings surviving on the moister site, followed by Elymus elymoides and Stipa comata . Survival of Agropyron , but not the native Elymus , was more depressed on the drier of the 2 sites planted in 1994. Stipa, Oryzopsis hymenoides , Pleuraphis , and Ephedra survived as well on the drier site as on the moister site, or better. On the 1995 planting sites Bromus was greatly reduced by the burn treatment, and, in contrast to the effect of burn treatments on the 1994 site, survival of all species except Oryzopsis and Ephedra was higher on burned than on unburned treatments. Overall, Stipa, Oryzopsis , and Pleuraphis had low emergence but consistently higher survival.     

Pilfering of stored seeds and the relative costs of scatter-hoarding versus larder-hoarding in yellow pine chipmunks

Yellow pine chipmunks ( Tamias amoenus ) scatter-hoard food during summer and autumn but must form a larder as a winter food source before winter begins. Yellow pine chipmunks do not larder-hoard large quantities of food during the summer, apparently because a summer larder could not be defended from pilferers. We tested the assumption that the rate of pilferage from an unguarded larder would be significantly greater than the rate of pilferage from surface caches (which are also unguarded by yellow pine chipmunks) during the summer and autumn. Buried plastic buckets were used as artificial nests containing larders of 1000 sunflower seeds or 200 Jeffrey pine ( Pinus jeffreyi ) seeds. The pilferage of larder contents was monitored daily and compared to pilferage of surface caches. Animals (yellow pine chipmunks and deer mice, Peromyscus maniculatus ) removed sunflower seeds from caches much faster than from larders, but caches of Jeffrey pine seeds disappeared much more slowly than pine seeds in larders. Further, animals removed pine seeds from larders more quickly than they did sunflower seeds from larders. The difference between seed species was probably because sunflower seeds have much stronger odors, which rodents readily detect, and because chipmunks prefer pine seeds over sunflower seeds. Yellow pine chipmunks must spend a considerable portion of their time foraging for seeds and may not be able to defend a large larder during summer.     

A classification of aquatic plant communities within the Nothern Rocky Mountains

A synecological study of aquatic macrophyte plant communities was conducted across northern Idaho and western Montana during the summers of 1997, 1998, and 1999. A total of 111 natural and man-made water bodies were sampled based on a stratification of environmental variables thought to influence plant species distribution (i.e., elevation, landform, geology, and water body size). Plant species foliar cover data were used to develop a hierarchical, floristic-based community type classification with TWINSPAN and DECORANA software. Six planmergent (conspicuous portion of vegetative plant body on the water surface) and 24 submergent (vegetative plant body found primarily underwater) community types were identified. Multivariate analysis indicated that all community types displayed significant differences in plant species composition, and the Sorensons floristic similarity between communities averaged 10% for planmergent and 8% for submergent types. Canonical correspondence analysis was used to inspect relationships between abiotic factors and plant species abundance. Results of this analysis indicated some relationships between species distributions and abiotic factors; however, chance introduction of plant species to water bodies is a process considered to be equally important to the presence of the community types described.     

Temperature and high salinity effects in germinating dimorphic seeds of Atriplex rosea

Atriplex rosea L. (Chenopodiaceae; tumbling orach), an annual herb, is a widely established weedy species of disturbed sites in all counties of Utah. Seeds of Atriplex rosea were collected from a salt marsh in Faust, Utah, and are dimorphic, light brown, and 2-2.5 mm wide, or black and 1-2 mm wide. Seed germination responses of the black and brown seeds were studied over a range of salinity and temperature. Both brown and black seeds germinated at 1000 mM NaCl, and the optimal temperature for germination of both types was 20°-30°C. Variation in temperature, however, affected germination of black seeds more than brown seeds. At lower thermoperiod only 40%-50% black seeds germinated in nonsaline control, and germination was almost completely inhibited with the inclusion of salinity. However, all brown seeds germinated in control at temperatures above 5°-15°C, and inhibition caused by salinity was comparatively lower. Brown seeds had a higher germination rate than black seeds at all temperature and salinity treatments. The highest rate of germination of both seeds occurred at the temperature regime of 5°-15°C. Recovery of germination for black seeds when transferred to distilled water after being in various salinity treatments for 20 days was quite variable. Recovery decreased with increase in salinity at lower temperature regimes, increased with salinity at optimal thermoperiod, and had no effect at 20°-30°C. Brown seeds recovered poorly from salinity at all thermoperiods except 5°-15°C, where recovery decreased with an increase in salinity. Brown seeds are adapted to germination in the early part of the growing season, whereas black seeds are capable of surviving harsher conditions and can germinate in later time periods. Characteristics of the dimorphic seeds increase chances for survival in the harsh saline desert environment.     

Number and condition of seeds in ponderosa pine cones in central Arizona

Ponderosa pine cones from 10 areas in Arizona were collected prior to natural seed dispersal and dissected to determine the number of sound, hollow, and insect-damaged seeds in each cone. Total and sound seed yields per cone did not vary significantly among areas but did vary significantly among trees within each area. Numbers of hollow and Megastigmus -infested (Hymenoptera: Torymidae) seeds varied significantly among areas and trees within areas. Numbers of sound seed increased significantly with increasing cone length but did not change with increasing numbers of cones per cluster. The percentages of Megastigmus -infested seed did not change significantly with increasing cone length or number of cones per cluster.     

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.