Infection of young Douglas-firs by dwarf mistletoe in the Southwest

Studies in several areas in Arizona and New Mexico show that dwarf mistletoe ( Arceuthobium douglasii ) is rare in young Douglas-firs growing under infected overstories. Less than 5% of the Douglas-firs under 26 years old and less than 6% of those under 1.4m tall were infected in 77 mistletoe-infested stands. Both percent infection and mean dwarf mistletoe rating of young Douglas-firs increased as tree age, height, and stand dwarf mistletoe ratings increased.     

A new Hypsiglena from Tiburon island, Sonora, Mexico

This third report on the herpetofauna of Chihuahua deals exclusively with amphibians. The first plethodonid salamander is reported, species Ambystoma rosaceum is discussed in greater detail than before, and two subspecies are recognized. Spea is elevated from subgeneric to generic rank, and S. stagnalis Cope is removed from synonymy and is recognized as a subspecies of hammondii . The species listed include the following: 2 salamanders and 19 anurans (1 Scaphiopus , 2 Spea , 9 Bufo , 1 Eleutherodactylus , 2 Hyla , 3 Rana , and 1 Microhyla ). Reference is made to vaious habitats that are associated with elevations arising form lower deserts and extending into the western mountains. The role played by the dry and wet annual cycles is also noted.     

Forage quality of rillscale ( Atriplex suckleyi ) grown on amended bentonite mine spoil

At peak standing crop, rillscale ( Atriplex suckleyi ) foliage grown on amended bentonite mine spoil contained adequate digestible energy, crude protein, and all mineral elements except phosphorus necessary for cattle, sheep, antelope, and deer. Amendments (sawdust, NPK, gypsum) generally did not affect forage quality. Iron, manganese, aluminum, sodium, and potassium concentrations were high and may have adversely affected forage quality. Forage utility would be limited to a few months during the growing season.     

Reproduction of the prairie skink, Eumeces septentrionalis , in Nebraska

Clutch sizes of the prairie skink, Eumeces septentrionalis , in Nebraska are positively correlated with female snout-vent lengths (SVLs). Data presented in this study and others indicate Nebraska populations of E. septentrionalis have larger average clutch sizes than other populations within this species' range.     

Contributions to the life history of Sacramento perch, Archoplites interruptus, in Pyramid Lake, Nevada

During a two-year period (1976&ndash;1977), 180 Sacramento perch ( Archoplites interruptus ) were sampled from Pyramid Lake, Nevada, on a monthly basis using several capture methods in all lake areas. Age and growth determinations of these fish were inconsistent with previous research on this species. Sacramento perch are entirely carnivorous, adults feeding primarily on tui chub ( Gila bicolor ). Fish accounted for 6 percent of the diet (by volume) of Sacramento perch less than 300 mm fork length, and 98 percent for those exceeding 300 mm. Amphipods, Odonata, and Chironomidae composed 6.3, 5.7, and 1.8 percent, respectively, of the stomach contents by volume for all sizes combined. Females spawned from June to August when water temperatures approached 20 C, and their gonad weight was about 6 percent of the total body weight. A sample of 20 female perch had a mean fecundity of 84,203 eggs. The mean diameter of mature eggs was 0.88 mm. Sacramento perch almost exclusively inhabit the littoral zone of Pyramid Lake. Activity, as indicated by net catches, was greatest during the warm months of May to October. Monthly catches were significantly correlated with temperature (r = 0.577, P < 0.01). No short-term changes in population abundances were observed during 1976&ndash;1977.     

Summer food habits of coyotes in central Wyoming

Summer food habits of coyotes ( Canis latrans ) were investigated on a 3100-km 2 area in central Wyoming, divided into one deer-use area and five non-deer areas. Analysis of 404 scats (fecal samples) revealed an overall average of 63 percent occurrence of native ungulates, 63 percent leporids, 46 percent rodents, 14 percent livestock, and 11 percent birds. Pronghorn ( Antilocapra Americana ) was the ungulate most frequently consumed, occurring in about 87 percent of the scats. Mule deer ( Odocoileus hemionus ) occurred in only 8 percent, and in 5 percent the native ungulate remains were not identifiable beyond order. This large percentage of big game in the diet is apparently unusual, because big game has been of minor importance in most coyote food-habit studies. The high incidence of leporids is consistent with other studies performed in arid intermountain areas. Although cricetines, especially deer mice ( Peromyscus maniculatus ), were trapped consistently in all habitats, months, and trapping areas, they were found in scats at a lower frequency than microtines and sciurids. This suggests a coyote hunting strategy that selected for the latter two groups.     

Range extension of Helianthus spp. (Asteraceae) in Arizona and Utah

Two populations of Helianthus niveus (Benth.) Brandegee ssp. canescens (A. Gray) Heiser were discovered in northern Arizona extending the range 300 miles north for this species. Helianthus deserticola Heiser range was extended 100 miles east in both Arizona and Utah.     

Mountain ants of Nevada

The nest of the ant Formica propinqua W. M. Wheeler is reported from Washoe Co., Nevada.     

Growth of juvenile American lobsters in semiopen and closed culture systems using formulated diets

Growth of juvenile American lobsters, Homarus americanus , raised in four semiopen culture systems, with daily water exchange rates ranging from 29 percent to 3.3 percent, was compared with growth in a completely closed system. Animals were fed a formulated pelleted ration, water quality factors were measured daily, and changes in concentration of nitrate, orthophosphate, and total organic carbon were monitored. Results of two 90-day trials indicate that growth increased in the system with the lower water exchange rates. Maximum growth occurred in the closed system.