Thermal ecology and activity patterns of the short-horned lizard ( Phrynosoma douglassi ) and the sagebrush lizard ( Sceloporus graciosus ) in southeastern Idaho

A mark - recapture study of the short - horned lizard ( Phrynosoma douglassi ) and the sagebrush lizard ( Sceloporus graciosus ) was performed from 1976 to 1977 in southeastern Idaho. Both species had mean cloacal temperatures of approximately 33 C. However, P. douglassi had more variable cloacal temperatures, particularly during morning and evening periods. This was caused by differences in sleeping sites chosen by the two species. Adults of both species were active from mid - April through late August, with peak activity in June. Juvenile P. douglassi displayed a seasonal activity pattern similar to that of adults. Juvenile S. graciosus were most active later in the year (August), when adults were disappearing. In both species, young - of - the - year appeared in early to mid - August. Adult and juvenile P. douglassi were active during all daylight hours and displayed no activity peaks, whereas young - of - the - year displayed a bimodal activity pattern. Adult and juvenile S. graciosus were active over all daylight hours but had peak activity between 1200 and 1500 h. Ants ( Pogonomyrmex ) were the lizard's principle prey. However, only young - of - the - year P. douglassi had activity patterns that paralleled that of ants on their mounds.         

Body size, organ size, and sex ratios in adult and yearling Belding ground squirrels

A five - year study of Belding ground squirrels was conducted at high altitude in the Sierra Nevada. Body weight and body length varied seasonally depending upon the fat depletion - deposition cycle, age, and sex. Adult males tended to be heavier and longer than adult females, particularly in the last half of the active season. A similar pattern was present in yearlings. Yearling squirrels were often distinguishable from adults on the basis of body size. Mean body weights were greater in adults throughout the season, and mean body lengths were greater in adults through the first half of the season. Adults also had larger internal organs than yearlings at the beginning of the season. In liver and heart this difference was sustained. Sex ratios in adults and in yearlings were 1:1 but there was considerable spatial and temporal asymmetry in distribution of the sexes. Males tended to live in areas peripheral to lush meadows occupied by females and young.       

Reproductive cycle of the Belding ground squirrel ( Spermophilus beldingi beldingi ): seasonal and age differences

The reproductive cycle in Belding ground squirrels was studied in the Sierra Nevada Mountains at two locations, one at 2,100 m elevation, the other at 3,000 m. Adults emerged from hibernation completely prepared physiologically for reproduction. Males tended to emerge slightly ahead of females and yearlings tended to emerge later than adults. Yearling females were fertile but produced smaller litters than adults, 4.48 vs. 6.31. Yearling males were infertile. They exhibited a slight seasonal cycle in testicular growth but did not reach sexual maturity. Testicular growth and spermatogenesis were incipient in many adults and in yearlings prior to hibernation.       

Sexual dimorphism in malpighian tubules of Pteronarcys californica Newport (Plecoptera)

The Malpighian tubules in female nymphs and adults of Pteronarcys californica Newport are larger and whiter than in males. This difference is detectable in nymphs as small as 300 mg in live weight (final instar nymphs weigh 800 to 1600 mg depending on sex), and is most pronounced in late nymphs and adults. These differences are thought to be related to the increased excretory load imposed by the synthesis of ooplasm in the late female nymph and adult.         

Food habits of clouded salamanders ( Aneides ferreus ) in Curry County, Oregon (Amphibia: Caudata: Plethodontidae)

Stomach contents of 650 clouded salamanders ( Aneides ferreus ), collected monthly throughout the year from Curry County, Oregon, were examined. Samples from three age classes were involved: (1) 489 adults, (2) 131 juveniles, and (3) 30 hatchlings. Foods did not vary by sex, but did vary by age and by season. Hatchlings ate small items, particularly mites, springtails, flies, and small beetles. Juveniles fed mainly on flies, isopods (sowbugs), beetles, mites, and centipedes in winter; beetles, ants, and isopods in spring; ants and beetles in summer; and isopods, beetles, and ants in fall. Adults ate isopods and beetles as their major foods in winter, spring, and fall and isopods, ants, beetles, and earwigs in summer. Four species were exceedingly important as foods for these salamanders: an unidentified isopod, the snout beetle ( Trachyphloeus bifoveatus ), the European earwig ( Forficula auricularia ), and an ant ( Lasius alienus ).       

Body fat, body water, and total caloric value of Uinta ground squirrels

The weight of body water and fat-free dry weight of Uinta ground squirrels ( Spermophilus armatus ) is given as a function of body weight. Body fat is presented as a function of body weight and body length. An equation for calculating the total caloric content of Uinta ground squirrels is given. Fat index (weight of fat/fat-free dry weight) values of juveniles increased from 0.11 to 0.22 from 5 June to 28 July. In male yearlings and adults the fat index increased about 8 to 9 times in the latter half of June and early July.         

The life cycle of Hydroperla crosbyi (Plecoptera: Perlodidae)

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Sexual selection and mating system variation in anuran amphibians of the Arizona-Sonoran Desert

Mating system variation in anuran amphibians of the Arizona - Sonoran Desert was reviewed. Male density and breeding period duration were negatively correlated in seven bufonids and pelobatids. Variation in male mating behavior and ability of females to freely select their mates unhindered by active - searching males also was related directly to male density. These observations support hypotheses relating ecological factors to mating system organization. It is suggested that male calling behavior, and anuran lek mating systems in general, may be significantly influenced by predation on vocalizing males.           

Invasion and stabilization of recent beaches by salt grass ( Distichilis spicata ) at Mono Lake, Mono County, California

Invasion of plant species onto recently exposed beaches of Mono Lake, California, was documented. Three vegetation zones were evident on these beaches. The first was formed entirely of annual species. The second was composed of annuals mixed with salt grass, and the third was formed entirely of salt grass. Stabilization of these beaches was accomplished by the aggressive growth of salt grass rhizomes.         

Winter preference, nutritive value, and other range use characteristics of Kochia prostrata (L.) Schrad

A cafeteria - style study was conducted during the winter for two years with tame mule deer to determine if there were preferential differences between accessions of forage kochia ( Kochia prostrata ). Deer consumed significantly more of P.I. numbers 314929, 330708, and 356826 than any of the other accessions. Other plant adaptive characteristics and nutritive qualities are also reported.         

Use of biomass predicted by regression from cover estimates to compare vegetational similarity of sagebrush-grass sites

Regressions between vegetational cover, estimated with a two - tiered, gridded sampling frame, and biomass were used to obtain predicted biomass values from cover values. Comparisons of eight sites based on predicted biomass data and comparisons of the sites based on cover data indicate that predicted biomass data may better identify differences among sites. Also, some suggestions are made regarding the methods of using cover - biomass regressions to obtain predicted biomass values.         

Aspects of the biology of the flathead chub ( Hybopsis gracilis ) in Montana

Mature flathead chubs ( Hybopsis gracilis ) were present in mid - July and mid - August collections from the Musselshell River, Montana. The estimated numbers of mature eggs present in eight females were 360–753 per female. The smallest mature female and male collected were 113 and 123 mm in total length, respectively. The male to female sex ratio in collections was about 1:1. Only small differences were detected among the length – weight relationships of males and females and samples taken from various seasons and localities in Montana. Observations on size groups, fish associates, and habitat characteristics of flathead chubs are presented.         

High rates of photosynthesis in the desert shrub Chrysothamnus nauseosus ssp. albicaulis

  Basic aspects of photosynthesis were investigated in white rubber rabbitbrush ( Chrysothamnus nauseosus (Pallas) Britt. ssp. albicaulis ), a common C 3 deciduous shrub native to arid regions of the western U.S. Under favorable field conditions, net photosynthesis (P n ) ranged from 36 to 73 mgCO 2 · dm – 2 · hr – 1 , which is relatively high for a woody species. The leaves from the actively growing flowering shoots exhibited higher P n than those on the vegetative shoots. P n also varied according to the age of the leaves and the location of the plants. P n did not light saturate even at quantum flux densities (QFD) equivalent to full sunlight. The light compensation point was relatively high (ca 100 μ mol · m – 2 · S – 1 ), perhaps due to the presence of a tomentose vestiture on the leaf surface. At high QFD's, the stomatal conductance was high (ca 520 mmol · m – 2 · s – 1 ) for a woody species. RUBP - carboxylase content of the leaves ranged from 20 to 22 mg per gram F.W., which is similar to that found in most C 3 crop species. These results suggest that rabbitbrush is able to maintain high rates of P n , at least under nonstressed conditions.           

Ecological studies of a regulated stream: Huntington River, Emery County, Utah

A 36.9x10 6 m 3 reservoir constructed on Huntington River, Emery County, Utah, resulted in changes in physical habitat, water quality, temperature, and flow regime. The greatest changes in physical habitat resulted from: (1) sediment additions from dam and road construction plus erosion of reservoir basin during filling; and (2) changing stream flow from a spring high runoff regime to a moderated flow regime. Elimination of spring nutrient concentration peaks and overall reduction of total dissolved nutrient availability in the river plus moderate reductions in pH were the most apparent water quality changes below the reservoir. Water temperature changes were an increased diurnal and seasonal constancy, summer depression, and winter elevation, generally limited to a 10–12 km reach below the dam. Physical and chemical changes altered macroinvertebrate community structure, with changes greatest near the dam and progressively less as distance downstream increased. Below the dam: (1) more environmentally tolerant taxa increased their dominance; (2) relative numbers of smaller sized individuals increased in relation to larger individuals; and (3) filter feeding, collector/gatherers, and scrapers gained an advantage over shredders. Insect taxa such as Rhithrogena robusta, Pteronarcella badia, and Ephemerella doddsi were eliminated from stream reaches near the dam, and other taxa such as Arctopsyche grandis, Chironomidae, and Simuliidae increased in numbers. Late spring to early summer egg hatch proved to be a disadvantage to Brachycentrus occidentalis, and B. americanus, with a fall hatch, was less impacted by altered river flow patterns. Macroinvertebrate taxa with small instar larvae present from late summer to early fall were negatively impacted by the unnaturally high July and August flows. The reservoir became a physical barrier to downstream larval drift and upcanyon and downcanyon immigration of adults, resulting in reduced numbers of several species above and below the reservoir.         

Host-parasite studies of Trichophrya infesting cutthroat trout ( Salmo clarki ) and longnose suckers ( Catostomus catostomus ) from Yellowstone Lake, Wyoming

Trichophrya sp. (Protozoa) on the gills of cutthroat trout ( Salmo clarki ) and longnose suckers ( Catostomus catostomus ) was studied using light and electron microscopy and tracer techniques. All cutthroat trout, 14 cm in total length and above, from Yellowstone Lake, Yellowstone National Park, Wyoming, were infested with the suctorian. No trichophryans were found on fry or fingerling cutthroat trout. Sixty percent of the examined longnose suckers from the same location were infested. Light microscopy disclosed extensive pathology of gill epithelium in longnose suckers infested with Trichophrya that was not observed for infested cutthroat trout. Electron micrographs show damage to immediate host gill cells by both parasites, depicted by a reduction and lack of mitochondria. Both parasites form attachment helices (0.52 × 0.04 μ m), which may originate in the protozoan cell membrane and function for maintenance of parasite position on the host cell. There was no uptake of 14 C, injected into host fish, via the attachment helices by the parasite that further substantiated the mechanical function for the spiral structure. Protozoan feeding on host tissue may be accomplished by use of necrotic gill tissue and mucus.        

Spatial patterns of plant communities and differential weathering in Navajo National Monument, Arizona

Vegetation patterns in Navajo National Monument, Arizona, were studied over a five-year period from 1977 to 1981. Twelve distinct plant community types occur within the boundaries of the park. These communities are characterized and the dominant plant species of each are recorded. The relationships of parent material, soils, and moisture to plant communities are also discussed. It appears that discrete communities occupy soils of different characteristics, particularly with respect to amount of weathering of parent material.         

A survey and assessment of the rare vascular plants of the Idaho National Engineering Laboratory site

A two-year study of the rare vascular plants of the Idaho National Engineering Laboratory generated new data on the abundance, distribution, and habitat features of eight taxa presently under review at either the federal or state level, or recently proposed for such review. Astragalus ceramicus Sheld. var. apus Barneby is common on the INEL and adjacent areas and will be recommended for removal from further consideration at the federal level and placed on Idaho's Federal Watch List. Coryphanta missouriensis (Sweet) Britt. & Rose is common throughout east central Idaho, but will be recommended for retainment on the State Watch List. Gymnosteris nudicaulis (H. & A.) Greene and Oxytheca dendroidea Nutt. are also recommended for retention on the State Watch List. Four taxa not previously known to occur in Idaho or not known from the southeastern part of the state ( Astragalus gilviflorus Sheld., Astragalus kentrophyta Gray var. jessiae (Peck) Barneby, Gilia polycladon Torr., and Lesquerella kingii S. Wats. var. cobrensis Roll. & Shaw) were encountered and evaluated with reference to current or potential threats, and are recommended for placement on Idaho's State Watch List.         

Annotated key to Eriogonum (Polygonaceae) of Nevada

Seventy - three species of Eriogonum (Polygonaceae) are reported for Nevada. A key is provided for the identification of these species along with brief notes on their distribution in the state and elsewhere.         

New variety of Yucca harrimaniae (Agavaceae) from Utah

Yucca harrimaniae var. sterilis Neese & Welsh is named and described from the Uinta Basin of Utah. The plant is strongly rhizomatous, evidently sterile, and has limber, sparingly filiferous leaves that tend to recline on the ground.         

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.