Note on the occurrence of Siphlonurus autumnalis (Ephemeroptera: Siphlonuridae) in a Montana spring brook

The little-known mayfly Siphlonurus autumnalis McDunnough (Ephemeroptera: Siphlonuridae) was collected from several locations in its floodplain habitats along the Middle Fork of the Flathead River in western Montana. To confirm identification, nymphs were reared along with an associated species, S. occidentalis Eaton (Ephemeroptera: Siphlonuridae). Adults emerged from 6 September until 16 October. Habitats are described and the first photos of the 2 sexes are provided.     

Additions to the vascular flora of Montana and Wyoming

A list of one taxon new for Montana and 10 new for Wyoming is presented, plus comments about Astragalus molybdenus.     

Winter and early spring bird communites in grasslands, shrubsteppe, and juniper woodlands in central Oregon

We compared winter (December, January, and February) and early spring (March and April) bird communities among 4 successional stages that included grassland, shrubsteppe, juniper-shrubsteppe, and old-growth juniper woodland in central Oregon. Birds were surveyed monthly from December through April in 1998/1999 and 1999/2000 using the point count method to estimate relative abundance of birds (individuals ? transect –1 year –1 ). We used distance sampling to correct for potential bias in estimating abundance and density among successional stages. A total of 4513 birds (32 species) were detected. Relative abundance of total birds (all species combined) was similar in the juniper-shrubsteppe and old-growth woodland (48.7 and 48.9 individuals ? transect –1 , respectively) but 6 times greater than in the grassland and shrubsteppe (8.0 and 7.7 individuals ? transect –1 , respectively) during the 5-month period. Total density of birds was greater in old-growth juniper woodland and juniper-shrubsteppe than in grassland or shrubsteppe. However, median bird species richness in 1998/1999 was highest in grassland and lowest both in shrubsteppe and juniper-shrubsteppe, and in 1999/2000 it was highest in shrubsteppe and lowest in juniper-shrubsteppe and oldgrowth juniper woodland. American Robins and Townsend's Solitaires were the most abundant species in junipershrubsteppe and old-growth juniper woodland during the winter months. Sage Sparrows and Horned Larks were the most abundant species in shrubsteppe during winter, and Horned Larks were most abundant in grasslands during the early spring transition period prior to nesting. Our results indicate that a different suite of species use these successional stages during the nonbreeding season. If avifauna conservation is a part of long-term management goals, a broad range of successional stages should be maintained on the landscape to provide habitat for a variety of avian species throughout the year.     

Ecophysiology of the temperate desert halophytes: Allenrolfea occidentalis and Sarcobatus vermiculatus

Numerous basins of the intermountain area often have extensive playa surfaces that are nearly devoid of vegetation. Margins of these playas support sparse communities dominated by chenopod shrubs Allenrolfea occidentalis (iodine bush) and Sacrobatus vermiculatus (black greasewood). These plants establish and persist in an environment where halomorphic soils induce extreme osmotic stress and atmospheric precipitation is very low and erratic and occurs largely during the winter when temperatures are too low for growth. We measured net CO 2 assimilation rates, leaf conductances, transpiration rates, water-use efficiencies, and stem xylem potentials for these two C3 species. Data were collected in above-average (1991) and below-average (1992) precipitation years. Net CO 2 assimilation rates for Allenrolfea were statistically similar in 1991 and 1992 but in general declined for Sarcobatus in 1992. For both species, leaf conductances and leaf transpiration rates declined significantly from 1991 to 1992, with the decline greater for Sarcobatus . Water-use efficiencies doubled from 1991 to 1992 for both plant species. Predawn xylem water potentials were -2.2 and -3.3 MPa for Allenrolfea and -1.8 and -2.6 MPa for Sarcobatus by September 1991 and 1992, respectively. Afternoon xlem water potentials were -3.1 and -2.0 MPa for Allrolfea and -2.6 and -2.2 for Sarcobatus beginning in May 1991 and 1992, respectively. Xylem water potentials dropped to -5.0 MPa for Allenrolfea and -3.4 MPa for Sarcobatus by September for both 1991 and 1992. For Allenrolfea , in general, the total soil water potential within the zone of maximum root activity is more negative than the plant's predawn xylem potential, which suggests that the plant is partially phreatophytic and/or has a large capacitance due to its extensive woody root system.     

SEM analysis of Utah Equisetum stems (Equisetaceae)

The Utah taxa of Equisetum were observed with the scanning electron microscope to test for taxonomic significance of stem morphology. The four Utah species of Equisetum were compared. Stem morphology was shown to be taxonomically significant in most cases. The hybrid E. x ferrissii , recognized in the literature as being extant in Utah but heretofore unrecognized in Utah herbaria, was shown to be present in the flora of the state.     

Southern range extension of the white fir dwarf mistletoe in Arizona

Discovery of a small isolated population of the white fir dwarf mistletoe, Arceuthobium abietinum f. sp. concoloris, in the Chiricahua Mountains of southeastern Arizona extends the southern distribution of this mistletoe 300 miles. The rare occurrence of the mistletoe in the southwest suggests that it once had a more southerly distribution but only survived past climatic changes in a few locations.     

The taxonomic status of the rosy boa Lichanura roseofusca (Serpentes: Boidae)

Evidence is presented indicating that Lichanura roseofusca and Lichanura trivirgata are conspecific. Data include the report of an intermediate specimen from El Arco, Baja California Norte, a site midway between the previously known peninsular ranges of the two species; captive hybridization provides additional support for the conclusion.     

An annotated list of the aquatic insects of southeastern Idaho, Part II: Trichoptera

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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.