Tree densities on pinyon-juniper woodland sites in Nevada and California

The densities of sing le leaf pinyon and Utah juniper trees in four diameter classes (1–9, 10–19, 20–29, and ≥ 30 cm) were measured on 522 plots of 1/10 ha each throughout the Great Basin. Density distribution patterns of pinyon and juniper varied with aspect, elevation, and eastern (EGB) versus western Great Basin (WGB) locations. On most locations north and, to a lesser extent, west slopes supported higher densities of pinyon than south and east slopes, with high relative densities of small diameter trees on north slopes and large diameter trees on west slopes. Pinyon densities were higher on EGB than on WGB sites and on higher elevation than on lower elevation sites. Juniper densities were higher on EGB than on WGB sites and on lower elevation than on higher elevation sites. Juniper densities on low-elevation WGB sites were higher on south and west aspects than on north and east, with higher relative densities in the 20–29 cm diameter class than in other diameter classes. On low elevation EGB sites, east and south slopes supported higher juniper densities than did north and west slopes, with comparatively higher relative densities in the 10–19 cm diameter class. Differences in relative densities between diameter classes were not significant among aspects on high elevation sites.     

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.     

Emergence of adult pandora moths in Arizona

Adult pandora moths began emerging in late July, and peak daily emergence occurred during 10&ndash;15 August. The mean density of moths emerging per 929 cm 2 of ground surface ranged from 0.1 to 2.4. The ratio of emerging males to females varied from 3&ndash;4:1 during the initial days of emergence to 1:1.5 during the last 10 days of August. Postemergence behavior is described and discussed in relation to egg mass deposition and species survival. &nbsp;&nbsp;&nbsp;     

Mycorrhization of ponderosa pine in a second-growth Sierra Nevada forest

Ectomycorrhizal colonization and rooting characteristics were quantified in a mature ponderosa pine ( Pinus ponderosa Dougl. ex Laws.) stand in the western Sierra Nevada. Root length totaled 3835.9 m &middot; m &ndash;2 of forest floor surface area, with 96% consisting of the fine-root fraction. Total root dry weight and volume were 2230.4 g &middot; m &ndash;2 and 5807.4 cm 3 &middot; m &ndash;2 of forest floor area, respectively, with 69% of the former and 75% of the latter accounted for by the coarse fraction. Fine roots were most prevalent in the upper 15 cm of the mineral soil profile, and their abundance declined with increasing depth. Coarse roots were most abundant at a depth of 15&ndash;30 cm. Ectomycorrhizal counts totaled 26,814 &middot; m &ndash;2 of forest floor area, and an overwhelming preponderance was associated with the fine-root fraction. More than three-quarters of mychorrhizae resided in the upper 15 cm of mineral soil, with an overall trend of declining numbers with increasing depth. Roots and mycorrhizae were exceedingly scarce at a depth of 45&ndash;60 cm, and neither was found in the organic soil layer above the mineral profile. A necessary step in understanding the ecophysiological role of mycorrhizae in mature forests is to quantify their abundance in such settings, and the results of this study contribute such information for ponderosa pine.     

Composition of forest stands used by White-headed Woodpeckers for nesting in Washington

In this study, I examined the composition of managed ponderosa pine ( Pinus ponderosa ) forests used by nesting White-headed Woodpeckers ( Picoides albolarvatus ) along the eastern slope of the Cascade Range in Washington. I sampled trees and snags using the point-centered quarter method to assess species composition, tree and snag density, and stand basal area in 16 forest stands containing White-headed Woodpecker nests. All stands had a history of timber management and 2 had been burned and salvage-logged. Mean live-tree density (&ge;10.16 cm dbh) was 182.3 trees &middot; ha &ndash;1 (SE = 13.52), mean snag density (&ge;10.16 cm dbh) was 11.5 snags &middot; ha &ndash;1 (SE = 1.92), and mean stand basal area was 17.2 m 2 &middot; ha &ndash;1 (SE = 1.58). Ponderosa pine had the highest importance value (mean = 220.9, SE = 17.25) of any tree species in all but 2 stands. Mean dbh of ponderosa pines was 33.0 cm (SE = 0.26) and ranged from 26.1 to 50.2 cm within stands. Mean density of ponderosa pine was greatest in the 20.3&ndash;30.5 cm dbh size class and lowest in the 50.8&ndash;61.0 cm and >61.0 cm dbh size classes. Tree density was up to 5.3 times greater than densities believed to be typical of ponderosa pine forests prior to fire suppression. Snag densities were within the range estimated for historical dry forests of the eastern Cascades, yet only 50% of all snags sampled had a dbh >25.4 cm. Although White-headed Woodpeckers are considered strongly associated with old-growth ponderosa pine, my results suggest that they may be more adaptable to using forests dominated by smaller diameter trees. En este estudio, examin&eacute; la composici&oacute;n de los bosques manejados de pino ponderosa ( Pinus ponderosa ), utilizados para anidamiento por el p&aacute;jaro carpintero cabeciblanco ( Picoides albolarvatus ), a lo largo de la vertiente oriental de la cordillera Cascade del Estado de Washington. Muestre&eacute; &aacute;rboles vivos y muertos usando el m&eacute;todo de cuadrantes al punto central en 16 rodales con nidos del p&aacute;jaro carpintero cabeciblanco para evaluar la composici&oacute;n de especies, la densidad de &aacute;rboles vivos y muertos y el &aacute;rea basal del rodal. Todas las &aacute;reas ten&iacute;an una historia de manejo maderable y 2 hab&iacute;an sido quemadas y taladas para recuperar madera. La densidad promedio de &aacute;rboles vivos (&ge;10.16 cm DAP) fue 182.3 &aacute;rboles &middot; ha &ndash;1 (DE = 13.52), la densidad promedio de &aacute;rboles muertos (&ge;10.16 cm DAP) fue 11.5 &aacute;rboles muertos &middot; ha &ndash;1 (DE = 1.92) y el &aacute;rea basal promedio de los rodales fue 17.2 m 2 &middot; ha &ndash;1 (DE = 1.58). El pino ponderosa tuvo el valor de importancia m&aacute;s alto (promedio = 220.9, DE = 17.25) de las especies de &aacute;rboles en todos, menos 2 rodales. El DAP promedio de los pinos ponderosa fue 33.0 cm (DE = 0.26) y variaba de 26.1 a 50.2 cm dentro de rodales. La densidad promedio del pino ponderosa fue la mayor en la clase de 20.3&ndash;30.5 cm DAP y menor de las clases de 50.8&ndash;61.0 cm y >61.0 cm DAP. La densidad de &aacute;rboles fue hasta 5.3 veces mayor que las consideradas t&iacute;picas para bosques de pino ponderosa antes de la intervenci&oacute;n para prevenir incendios. Las densidades de &aacute;rboles muertos estuvo dentro del rango estimado para los bosques secos hist&oacute;ricos del oriente de la cordillera Cascade, no obstante s&oacute;lo 50% de los &aacute;rboles muertos muestreados tuvieron un DAP >25.4 cm. Aunque se considera que los p&aacute;jaros carpinteros cabeciblancos est&aacute;n estrechamente asociados con bosques primarios de pino ponderosa, mis resultados sugieren que podr&iacute;an ser m&aacute;s adaptados a usar bosques donde predominan &aacute;rboles de di&aacute;metro menor.     

Pocket gophers ( Thomomys talpoides ) in successional stages of spruce-fir forest in Idaho

This study examined (1) the relative abundance of the pocket gopher ( Thomomys talpoides ) in four successive stages (1&ndash;10, 11&ndash;39, 40&ndash;79, and 80+ years following disturbance) of spruce-fir forest; (2) the relationship between number of gopher sign (mounds and earth plugs) with gopher density; and (3) a method of sampling pocket gopher populations using a 500 by 4 m strip transect. The number of gopher mounds was significantly correlated with the number of earth plugs. Data were pooled and a categorical log linear analysis used to test for significant differences in pocket gopher sign between the four successive stages. The 1&ndash;10 and the 80+ -year-old sites had significantly more gopher sign than the 11&ndash;39 and the 40&ndash;79 year-old sites. No significant differences were found between the 11&ndash;39 and the 40&ndash;79-year-old sites, or between the 1&ndash;10 and the 80+ -year-old sites. The difference in population densities may be due to understory vegetation differences between the successional stages. There was a significant correlation between amount of gopher sign and gophers caught in each of the study sites. This indicates that counts of pocket gopher sign may be used to estimate pocket gopher density. The strip transect is recommended as the most appropriate method when sampling heterogeneous habitats or when there is cause to suspect gopher populations may be aggregated within the area rather than spaced randomly or regularly.     

Seed germination characteristics of Chrysothamnus nauseosus ssp. viridulus (Astereae, Asteraceae)

Rubber rabbitbrush ( Chrysothamnus nauseosus [Pallas] Britt. ssp. viridulus ) may prove to be a source of high-quality cis-isoprene rubber, but its establishment is limited by a lack of information on seed germination. Consequently, seeds were germinated at alternating temperatures (5&ndash;15, 5&ndash;25, 15&ndash;25, and 20&ndash;30 C) in light and dark as well as constant temperatures (15&ndash;40 C with 5-C increments) to determine temperature response. Seeds were also germinated in solutions of polyethylene glycol 6000 (0 to &ndash;5 bar), salinity regimes (1, 17, 51, and 86 mM) at all the above-mentioned temperatures to determine salinity and temperature interaction. The hormones GA 3 (0, 2.9, 29.0, and 58.0 um) and kinetin (0, 4.7, 23.5, and 47.0 um) were used to study their effect on overcoming salt- and temperature-induced germination inhibition. Seeds of C. nauseosus ssp. viridulus were very sensitive to low temperature. Best germination was achieved at 25 and 30 C, but these seeds also germinated at a higher temperature (35 C). The seeds of rabbitbrush germinated at both constant and alternating temperatures. Light appears to play little or no role in controlling germination of the seeds of rubber rabbitbrush. However, seeds of rabbitbrush were sensitive to salinity, and seed germination was progressively inhibited by increase in salt concentration, although a few seeds still germinated at the highest saline level. Progressively higher concentrations of polyethylene glycol also progressively inhibited germination. Suppression of seed germination induced by high salt concentrations and high temperatures can be partially alleviated by the application of either GA 3 or kinetin.     

Climates of fescue grasslands of mountains in the western United States

Climates of fescue grasslands were described by summarizing USDC Weather Bureau records of representative sites. Mean temperatures of the warmest month declined from 18 to 14 C, average annual precipitation increased from 40&ndash;50 to 170 cm, and the number of arid months in an arbitrarily defined dry year declined from 3 to 1&ndash;2 as one moves from Festuca arizonica (14 stations) to F. scabrella (15) to F. idahoensis (17) to F. thurberi (6) to F. viridula (9). Climates of the grasslands are sufficiently like those of the Pseudotsuga menziesii and Abies lasiocarpa zones of the northern Rocky Mountains to make one ask what factors&mdash;wind, snow duration, soil characteristics, or fire&mdash;allow the fescue grasslands to persist in a conifer climatic zone.     

Estimating root biomass and distribution after fire in a Great Basin woodland using cores and pits

Quantifying root biomass is critical to an estimation and understanding of ecosystem net primary production, biomass partitioning, and belowground competition. We compared 2 methods for determining root biomass: a new soil-coring technique and traditional excavation of quantitative pits. We conducted the study in an existing Joint Fire Sciences demonstration area in the central Great Basin. This area is representative of a shrub (sagebrush) ecosystem exhibiting tree (pinyon and juniper) encroachment. The demonstration area had a prescribed burn implemented 4 years prior to our study, and we sampled both control and burned plots. The samples were stratified across 3 microsites (interspace, under shrub, and under tree) and 4 soil depths (0&ndash;8, 8&ndash;23, 23&ndash;38, and 38&ndash;52 cm) to determine the effects of plant life form and burning on root biomass. We found that estimates of total root biomass were similar between quantitative pits and our soil cores. However, cores tended to show a more even distribution of root biomass across all microsites and depths than did pits. Overall, results indicated that root biomass differs significantly among microsites and soil depths and that the amount of root biomass at a given depth differs among microsites. Burning reduced root biomass in our study by 23% and altered the spatial distribution of root mass.     

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

&nbsp; 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 &middot; dm &ndash; 2 &middot; hr &ndash; 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 &mu; mol &middot; m &ndash; 2 &middot; S &ndash; 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 &middot; m &ndash; 2 &middot; s &ndash; 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. &nbsp;&nbsp;&nbsp; &nbsp;     

Distribution and dynamics of waterbird habitat during spring in southern Oregon–northeastern California

The southern Oregon&ndash;northeastern California and extreme northwestern Nevada (hereafter &ldquo;SONEC&rdquo;) region provides critical spring migration habitat for waterfowl and other waterbirds in the Pacific Flyway. Information on the dynamics and distribution of waterbird habitats in SONEC during spring is needed to guide conservation efforts in the region. We grouped 1992 National Land Cover Data classes into 5 potential waterbird habitat types and used Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper Plus satellite imagery to map flooding of these habitat types in SONEC during February&ndash;May, 2002 and 2003. SONEC included 13,727 km 2 of potential waterbird habitat comprised of grasslands (37.1%), pasture/hay (24.6%), marsh (15.9%), open wetland (11.8%), and croplands (10.6%). On average, 11.9% of this potential habitat was flooded during spring; but the percentage, area, and composition varied within and among years and subregions. Total flooding increased from 693 km 2 in February to 2099 km 2 in April during 2002 and from 1630 km 2 in February to 2125 km 2 in May during 2003. Open wetland comprised 58%&ndash;74%, marsh 8%&ndash;18%, pasture/hay 4%&ndash;11%, grassland 4%&ndash;17%, and cropland 3%&ndash;8% of the flooded habitat in SONEC. Satellite imagery and land-use data provided useful estimates of waterbird habitat availability in SONEC during spring, but other methods should be tested to more accurately measure flooding of densely vegetated habitats such as marsh. With &#60;12% of the potential habitat flooded on average during spring, conservation programs have ample opportunity to improve the SONEC landscape for migrating waterbirds.     

Life history of the cui-ui, Chasmistes cujus Cope, in Pyramid Lake, Nevada: a review

The cui - ui, Chasmistes cujus Cope, a member of the sucker family and endemic to Pyramid Lake, Nevada, is listed as endangered by the U.S. Fish and Wildlife Service. Cui - ui was once a major source of sustenance for native Americans, who have inhabited the Lahontan region for at least 11,000 years. The Northern Paiutes developed sophisticated fishing technology to harvest this resource. The original distribution of cui - ui was the ancient Lake Lahontan complex, but as a result of climatic changes it was restricted to the Pyramid &ndash; Winnemucca &ndash; Truckee system by the turn of the 20th century. Transbasin water diversions (1905 to present) have resulted in further restrictions of habitat. The species is now limited to Pyramid Lake and the lower Truckee River. Reproduction is from hatcheries as well as limited natural reproduction. Females produce more than 40,000 2 - mm eggs per year. The normal development is described from the unfertilized egg through 912 hours post - hatching, when the fry are actively feeding and approaching adult body form. The unusual feature of adult cui - ui morphology is the relatively large ventro - terminal mouth, with thin and obscurely papillose lips. Cui - ui grow slowly and may live 18 years or possibly much longer; females generally live longer and attain a greater size than males. The highest adult mortality probably occurs during spawning runs. At this time they are vulnerable to predation, stress, and sometimes environmental degradation. The highest larval mortality probably occurs from predation when they are planted or migrate into the lake. The trophic ecology of the species is poorly understood, but they are known to ingest algae and zooplankton. Spawning behavior is documented. At present, natural reproduction is probably still the limiting factor for the cui - ui population. Cui - ui composed less than one percent of the total fish in Pyramid Lake during 1975&ndash;1977. During 1982 the largest cui - ui spawning run (13,000) in recent years occurred. The activity of cui - ui in the lake closely resembles that of the Tahoe sucker being most active during the spawning season each spring. Cui - ui inhabit the inshore - benthic zone and the pelagic waters of Pyramid Lake ( &nbsp;&nbsp;&nbsp;     

Bottom-up factors influencing riparian willow recovery in Yellowstone National Park

After the elimination of wolves ( Canis lupis L.) in the 1920s, woody riparian plant communities on the northern range of Yellowstone National Park (YNP) declined an estimated 50%. After the reintroduction of wolves in 1995&ndash;1996, riparian willows ( Salix spp.) on YNP&rsquo;s northern range showed significant growth for the first time since the 1920s. However, the pace of willow recovery has not been uniform. Some communities have exceeded 400 cm, while others are still at pre-1995 levels of &#60;80 cm mean height. We took intensive, repeated measurements of abiotic factors, including soil and water-table characteristics, to determine whether these factors might be contributing to the varying pace of willow recovery. Willows at all of our study sites were &ldquo;short&rdquo; (&#60;250 cm max. height) prior to 1995 and have recovered to varying degrees since. We contrasted &ldquo;tall&rdquo; (>250 cm max. height) willow sites where willows had escaped elk ( Cervus elaphus L.) browsing with &ldquo;short&rdquo; willow sites that could still be browsed. Unlike studies that manipulated willow height with fences and artificial dams, we examined sites that had natural growth differences in height since the reintroduction of wolves. Tall willow sites had greater water availability, more-rapid net soil nitrogen mineralization, greater snow depth, lower soil respiration rates, and cooler summer soil temperatures than nearby short willow sites. Most of these differences were measured both in herbaceous areas adjacent to the willow patches and in the willow patches themselves, suggesting that they were not effects of varying willow height recovery but were instead preexisting site differences that may have contributed to increased plant productivity. Our results agree with earlier studies in experimental plots which suggest that the varying pace of willow recovery has been influenced by abiotic limiting factors that interact with top-down reductions in willow browsing by elk.     

Effects of osmotic potential, potassium chloride, and sodium chloride on germination of greasewood ( Sarcobatus vermiculatus )

Greasewood ( Sarcobatus vermiculatus [Hook.] Torr.) (Chenopodiaceae) typically grows on salt-affected soils where its germination requirements may reflect characteristics necessary for establishment in saline environments. The objective of this study was to determine the effect of osmotic potential and specific ions on the germination of seeds from three populations of greasewood. Seeds were germinated at 20 C in solutions of polyethylene glycol with water potentials ranging from &ndash;0.3 to &ndash;2.2 MPa that contained 0 to 68480 &micro;mol&middot;L &ndash;1 sodium chloride (NaCl) or 0 to 53640 &micro;mol&middot;L &ndash;1 potassium chloride (KCl). Germination of two populations was reduced by increasing salt concentration and decreasing osmotic potential; germination of one population was reduced by declining osmotic potential. No seeds germinated at an osmotic potential lower than &ndash;1.6 MPa. For all populations, days to 50% of final germination increased and abnormal germination decreased as osmotic potential declined. Comparison of our results with those from other studies suggests geographic ecotypic development in response to osmotic potential and NaCl and KCl concentrations during germination.     

Monitoring Idaho fescue grasslands in the Big Horn Mountains, Wyoming, with a modified Robel pole

The reliability of monitoring visual obstruction and estimating standing herbage with a modified Robel pole was examined for high-elevation meadows in sedimentary soils on the Bighorn National Forest, Wyoming. Our objectives were to (1) test a modified pole graduated with 1.27-cm (0.5-inch) bands for estimating standing herbage based on linear regression of visual obstruction readings (VORs) on standing herbage, (2) validate the derived regression, (3) provide sample size estimates, and (4) develop guidelines for monitoring mountain grasslands. Each transect had 20 visual obstruction stations spaced 10 meters apart with 4 visual obstruction readings at each station. At 4 stations, vegetation within a 0.25-m 2 area was clipped at ground level. VORs and clipped standing herbage were averaged by transect for analysis. Visual obstruction reliably predicted average standing herbage (dry weights) for mountain meadows ( r 2 = 0.81, s x&macr; = 382 kg &sdot; ha &ndash;1 ). Standing herbage ranged from 387 kg &sdot; ha &ndash;1 to 3930 kg &sdot; ha &ndash;1 , with a mean of 1742 kg &sdot; ha &ndash;1 . A validation data set of 13 transects sampled across the range of variation in standing crop showed that 85% of transects fell within the 90% prediction limits. We recommend a minimum of 4 transects for monitoring key areas or small areas up to 259 ha (640 acres) when managers need to consider differences in VOR bands and address multiple objectives. Cluster analyses (ISODATA) applied to the pole readings resulted in 4 visual obstruction categories: short, short-intermediate, tall-intermediate, and tall. This tool provides a simple, reliable, and cost-effective (time-saving) alternative to clipping vegetation and obtaining dry weights for monitoring. Mention of a proprietary product does not constitute a guarantee or warranty of the product by USDA or the authors and does not imply its approval to the exclusion of other products that also may be suitable.     

Population ecology and reproduction of the Mexican mud turtle ( Kinosternon integrum ) in Tonatico Estado De México

Ecological data directly from the field are important in understanding the life history strategies of kinosternid species in the tropics. Herein we summarize the basic population ecology and life history of Kinosternon integrum in the municipality of Tonatico (southeastern Estado de M&eacute;xico, M&eacute;xico). From October 2003 to November 2004, we marked a total of 204 turtles and recaptured 118 of them. Mean population size using the Jolly-Seber model was 197 (95% CI 128&ndash;416) individuals, with a sex ratio of 1:1.7, biased to females. Males were larger than females in carapace length and plastron length. The reproductive season starts in late June and finishes in late October. The smallest female with oviductal eggs was 122 mm in carapace length. Mean clutch size was 4 eggs ( s = 1.77, range 1&ndash;8) and was significantly and positively related to body size. Mean egg length was 30.43 mm ( s = 2.24, range 23.92&ndash;35.96), mean width was 16.35 mm ( s = 1.01, range 12.99&ndash;18.30), and mean weight was 5.14 g ( s = 0.60, range 3.41&ndash;6.57). Mean egg length was significantly and inversely related to clutch size. Relative clutch mass (reproductive effort) was 0.043 ( s = 0.017, range 0.017&ndash;0.071), which is the smallest value reported for the genus Kinosternon. Additionally, there was no evidence of a pelvic restriction on egg size in this population. This is the first study that documents basic population ecology and reproductive characteristics for a single population of the most widespread freshwater turtle in Mexico.     

Growth and development of the western harvest mouse, Reithrodontomys megalotis megalotis

Growth rates, gestation period, litter size, reproductive age, sex ratios, and development were studied on 198 litters of Reithrodontomys megalotis megalotis (Baird). Growth was characterized by several standard skull and body measurements and was partitioned into four phases of 1 &ndash; 3, 4 &ndash; 12, 13 &ndash; 22, and 23 &ndash; 70 days. Growth was best described by measurements of tail length, ear length, and dried eye - lens weight. Reproductive activity began as early as 38 days for females and 59 days for males. The gestation period was 22 days, and the mean litter size was 3.83 (range 1 &ndash; 7). Sex ratio was 53.49 percent males to 46.51 percent females. Reproductive efficiency was 53.53 percent. The development of R. m. megalotis was very similar to that of R. m. dychei. Early breeding, postpartum estrous, year - round breeding, high reproductive efficiency, and a short gestation period contribute to a high reproductive potential in R. m. megalotis. &nbsp;     

Growth of Dipodomys ordii (Rodentia: Heteromyidae)

Growth rates were determined for laboratory - reared Dipodomys ordii pallidus Durrant & Setzer. Instantaneous growth rates were used to express increase of body weight, total length, tail length, ear length and hind foot length as rates between times of measurements and the instantaneous percentage of maximum size. Data were analyzed for growth periods of 1 &ndash; 3, 4 &ndash; 15, 16 &ndash; 29 and 30 &ndash; 70 days. All five parameters provided significant correlations of growth with age during all growth periods. Even though all of the growth parameters correlate with age, these parameters cannot be reliably used to predict age.     

Status and distribution of the Fish Creek Springs tui chub, Gila bicolor euchila

The Fish Creek Springs tui chub, Gila bicolor euchila , is present in large numbers throughout its native habitat in spite of extensive man-caused habitat disturbance. This subspecies occurs further downstream in Fish Creek than previously reported. &nbsp;     

Relative and seasonal abundance of three bark beetle predators (Coleoptera: Trogositidae, Cleridae) across an elevation gradient in ponderosa pine forests of north central Arizona

We examined abundance and flight periodicity of 3 predators of bark beetles (Coleoptera: Curculionidae, Scolytinae), Temnochila chlorodia (Mannerheim) (Coleoptera: Trogositidae), Enoclerus sphegeus (Fabricius) (Coleoptera: Cleridae), and E. lecontei (Wolcott) (Coleoptera: Cleridae), across an elevational gradient of ponderosa pine ( Pinus ponderosa Lawson) forests in north central Arizona. Predator populations were estimated at 10 sites in each of 3 elevation bands (low: 1600&ndash;1736 m; mid: 2058&ndash;2230 m; high: 2505&ndash;2651 m) for 3 years (2004&ndash;2006) using pheromone-baited funnel traps targeting 3 primary bark beetle species. We also investigated how predator abundance and flight seasonality related to those of 5 bark beetle species: Ips pini (Say), I. lecontei Swaine, Dendroctonus frontalis Zimmermann, D. brevicomis LeConte, and D. adjunctus Blandford. Temnochila chlorodia was most abundant in the low- and mid-elevation bands, whereas E. sphegeus was most abundant in the high-elevation band. Enoclerus lecontei showed no consistent elevational trend in abundance. Within each elevation band, changes in annual abundance of pooled predator species tracked shifts in abundance of pooled bark beetle species. In general, predator flight initiation coincided with or closely followed bark beetle flight initiation in the spring, but predator flight terminated before flight activity ended for most bark beetle species in the fall. In addition, the ratio of prey to predators was lowest in the summer and highest in the fall. This suggests that all bark beetle species examined may be provided temporal escape from their predators in the fall. For all 3 predator species, the pheromone-baited trap targeting D. brevicomis was less attractive than the pheromone-baited traps targeting I. pini and I. lecontei.