Diatom flora of Mink Creek, Idaho, USA

Diatoms were collected from an open-canopy and closed-canopy site on Mink Creek, Bannock County, Idaho, a third-order Rocky Mountain stream. Ninety diatom taxa were identified. Achnanthes minutissima Kuetz. And Navicula lanceolata (Ag. ) Kuetz. dominated the open-canopy site, whereas Cocconeis placentula var. euglypta (Ehr.)CI. comprised greater than 40% of the diatom assemblage at the closed-canopy site. Seven of the 10 most important diatoms were present at both sites. A high degree of similarity was evident between natural and artificial substrates at both sites. Although most taxa were present at both sites, it is apparent from this study that differences in the abundance of taxa occur according to variations in light.     

Range extension and ecological information for Orconectes virilis (Hagen 1870) (Decapoda: Cambaridae) in Idaho, USA

We report the 1st record of the crayfish Orconectes virilis (Hagen 1870) from Idaho and the Pacific Northwest, USA. We also provide an updated checklist of recent Idaho crayfishes, which now includes 2 families (Astacidae and Cambaridae), 3 genera ( Pacifasticus, Orconectes , and Procambarus ), and 7 species and subspecies ( Pacifasticus connectus (Faxon 1914), P. gambelii (Girard 1852), P. leniusculus leniusculus (Dana 1852), P. leniusculus klamathensis (Stimpson 1857), P. leniusculus trowbridgii (Stimpson 1857), O. virilis , and Procambarus clarkii (Girard 1852). Native crayfish were not found at the O. virilis collection sites. The localities where O. virilis was found were characterized by low-gradient streams impacted by fine sediment. Aquatic invertebrates found in association with O. virilis tended to be the more pollution-tolerant taxa.     

Density, distribution, and habitat of Flammulated Owls in Idaho

From 1990 to 1992 we surveyed for Flammulated Owls ( Otus flammeolus ) in 3 areas in Idaho: Salmon National Forest (SNF), Payette National Forest and adjacent Hells Canyon National Recreation Area (PNF-HCNRA), and Nez Perce National Forest (NPNF). We also collected and summarized information on all historic and modern records of Flammulated Owls in Idaho. Flammulated Owls were detected on 65% of 68 routes (2-16 km in length) surveyed at densities ranging from 0.04 to 1.25 singing males/40 ha. Owls were detected on survey routes as early as 10 May and as late as 23 July. Mean percent canopy cover estimated at owl locations on the PNF-HCNRA and NPNF study sites ranged from 52% to 64%, while shrub cover ranged from 16% to 21% and ground cover was 39% to 49%. Our surveys and summary of distributional records indicated that Flammulated Owls occur throughout the montane forests of Idaho in old or mature stands of open ponderosa pine ( Pinus ponderosa ), Douglas-fir ( Pseudotsuga menziesii ), and stands co-dominated by those 2 species. Fire suppression and timber harvest activity in ponderosa pine forests represent 2 main threats to the species' future security in Idaho. More research on the effects of various silvicultural treatments on Flammulated Owl populations is warranted.     

Reptiles and amphibians of Idaho, No 2

For about 20 years Richard P. Erwin collected amphibians and reptiles in southwestern Idaho. This report is an attempt to indicate some of his herpetological activities, and to list the numerous individuals, universities, and museums that were recipients of his collections.     

Distribution of sculpins in the Clearwater River Basin, Idaho

The distributions of Cottus bairdi, C. rhotheus, and C. beldingi exhibited a highly significant positive degree of association. Conversely, the distribution of C. confusus exhibited a highly significant negative association with the distributional complex, C. bairdi, C. rhotheus, and C. beldingi. These species of sculpins can be grouped into two assemblages; one based on the distribution of C. confusus and the other based on the combined distributions of the other three species. The factor or factors limiting the downstream distribution of C. confusus or the upstream distribution of the other three species could not be positively identified. However, we hypothesize that competition between C. confusus and one or more members of the C. bairdi, C. rhotheus and C. beldingi complex is involved. In the area of overlapping distributions among C. bairdi, C. rhotheus, and C. bairdi we hypothesize that resource partitioning is occurring. However, the data did not allow evaluation of this hypothesis.        

Nesting ecology of waterbirds at Grays Lake, Idaho

Montane wetlands provide valuable habitat for nesting waterfowl and other waterbirds in the western United States, but relatively little information is available about the nesting ecology of their waterbird communities. We describe the general nesting ecology of breeding waterbirds at a large, shallow, montane wetland in southeastern Idaho during 1997-2000. Habitats include upland grasslands and intermittently to semipermanently flooded wetland habitats. We located a total of 1207 nests of 23 bird species: Eared Grebe ( Podiceps nigricollis ), Canada Goose ( Branta canadensis ), Mallard ( Anas platyrhynchos ), Gadwall ( A. strepera ), American Wigeon ( A. americana ), Green-winged Teal ( A. crecca ), Blue-winged Teal ( A. discors ), Cinnamon Teal ( A. cyanoptera ), Northern Shoveler ( A. clypeata ), Northern Pintail ( A. acuta ), Redhead ( Aythya americana ), Canvasback ( A. valisineria ), Lesser Scaup ( A. affinis ), Ruddy Duck ( Oxyura jamaicensis ), Northern Harrier ( Circus cyaneus ), American Coot ( Fulica americana ), Virginia Rail ( Rallus limicola ), Greater Sandhill Crane ( Grus canadensis tabida ), American Avocet ( Recurvirostra americana ), Long-billed Curlew ( Numenius americanus ), Wilson's Snipe ( Gallinago delicata ), Wilson's Phalarope ( Phalaropus tricolor ), and Short-eared Owl ( Asio flammeus ). Most nests were initiated in May-early June and were terminated (hatched or destroyed) by the 3rd week of June. Mean daily survival rate (DSR) for Canada Goose nests was 0.954 ± 0.005 ( s ￣x ; n = 127 nests), equivalent to Mayfield nest success of 21%. Mean DSR for dabbling duck nests over all 4 years was 0.938 ± 0.006 ( n = 41), equivalent to Mayfield nest success of 11%. For all other species where we found > 10 nests each year (Eared Grebe, Redhead, Canvasback, Coot, Sandhill Crane, American Avocet, and Wilson's Snipe), > 50% of nests found hatched at least 1 young. Success rates for geese, cranes, and ducks were lower than reported for Grays Lake during 1949-1951 and lower than most other wetlands in the region.     

Ecology of Celtis reticulata in Idaho

The small deciduous tree Celtis reticulata (neatleaf hackberry) reaches its northern limit in Idaho, where, contrary to most of its western range, it often occurs as an overstory dominantly. Two hundred fifty stands of this tree were sampled throughout Idaho. Celtis is slow-growing, averaging 4 m tall at 50 yr, and long-lived (to 300-400yr). It occurs in a variety of habitats, from riparian to rocky uplands. Trees grow best where topographically sheltered, such as in draws and narrow canyons, and were soils are loamy. Although plants grow more slowly as surface rock cover increases, stands are often associated with rock, with a mean surface cover of 39% rock. Differences in growth rates were unrelated to parent material and aspect. Most stands are reproducing, in spite of habitat degradation caused by overgrazing, alien plant invasion, and increasing fire frequencies. Stands are typically represented by one dominant cohort; however, young, even-aged stands are rare and are generally found along waterways on stream terraces or at the high-water line. Although slow growing, C. reticulata shows promise for land mangers interested in site enhancement. This native species is long-lived, produces fruit used by wildlife, and provides structural diversity in a semiarid landscape (with a maximum height o 12 m) in areas that are becoming increasingly dominated by exotic plant species.     

Second occurrence of the long-nosed snake, Rhinocheilus lecontei lecontei, in Idaho

A second record of the long-nosed snake in Idaho was taken at the entrance to Bruneau Dunes State Park, Owghee County     

Vascular flora of Kane Lake Cirque, Pioneer Mountains, Idaho

Kane Lake Cirque lies in the western Pioneer Mountains of south central Idaho. An inventory of the high elevation flora of the cirque revealed the presence of 180 vascular taxa representing 95 genera and 30 families. Five alpine taxa are here documented from Idaho for the first time: Carex incurviformis Mack., Draba fladnizensis Wilfen., Potentilla nivea L., Ranunculus gelidus Kar. & Kir., and Ranunculus pygmaeus Wahlenb. Kane Lake Cirque also contains populations of four additional alpine taxa considered to be of conservation concern in Idaho: Erigeron humilis Graham, Parnassia kotzebuei Cham., Saxifraga adscendens L., and Saxifraga cernua L.     

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.         

Morphometry of sculpins ( Cottus ) in the Clearwater drainage, Idaho

The morphometry of four Idaho species of Cottidae were compared. Pectoral ray counts allowed separation of Cottus beldingi and C. confusus from C. bairdi and C. rhotheus but not from each other. Preopercular armature also allowed identification of the same two groups of two species. Palatine tooth development generally allowed separation of each species as did body prickle development. Body ratios involving caudal peduncle depth allowed separation of C. rhotheus and C. bairdi. Development of lateral lines allowed differentiation of C. rhotheus from the other three species. A key was developed based on the combination of characters studied.     

Size selection of food by cutthroat trout, Salmo clarki, in an Idaho stream

The mean size of food and amount of food consumed by cutthroat trout from Palisades Creek in southeastern Idaho increased with trout length. Number of organisms of terrestrial origin, number of aquatic larvae, number of ants, and number of berries from redstem dogwood were related to trout length. The size range and number of taxa consumed increased with trout size, indicating that as trout get larger, they broaden their feeding menu. The minimum size of food consumed was relatively constant for all trout, but larger trout appeared to feed more from the stream bottom. Trout may have a minimum length of food, below which items cannot be detected as food. Other possible factors affecting the feeding of cutthroat trout are mentioned.         

Food habits of Burrowing Owls in southeastern Idaho

Food habits of a population of the Burrowing Owl ( Athene cunicularia ) at the Idaho National Engineering Laboratory, Butte County, were studied. The 421 pellets examined yielded 2,436 prey items of at least 22 prey species. Invertebrates, largely insects, constituted 91 percent of the total prey items, but only 29 percent of the total biomass; mammals constituted 8 percent of the prey items, but 68 percent of the biomass. The prey were mostly nocturnal species; diurnal species were poorly represented.     

Invertebrate fauna of wastewater ponds in southeastern Idaho

Water column invertebrates were sampled with 3.8-L activity traps in 15 sewage, industrial, and radioactive wastewater ponds at the Idaho National Engineering Laboratory in southeastern Idaho. One collection was made per pond, per month, during all months the ponds were ice-free from June 1990 through July 1991. Arsenic, barium, boron, lead, selenium, and mercury were detected in ponds. Sewage ponds generally had higher nitrogen and phosphorus levels than industrial and radioactive ponds. Of the 30 aquatic invertebrate taxa collected, the most ubiquitous were Rotifera, Daphnidea, Eucopepdoa, Ostracoda, Acari, Baetidae, Corixidae, Notonectidiae, Dytiscidae, and Chironomidae. Activity trap samples from sewage ponds contained more Rotifere, Daphnidae, and Notonectide, whereas industrial ponds yielded more Chydoridae, Acari, and Baetidae. Numbers of Oligochaeta, Eucopepoda, Ostracoda, Corixidae, Dytiscidae, and Chironomidae collected were not significantly different between sewage and industrial ponds. Compared with natural systems, these ponds had fewer taxa, but a greater number of individuals of most taxa. The high number of invertebrates collected is attributed to the lack of fish in wastewater ponds and the high levels of nitrogen and phosphorus, particularly in sewage ponds.     

Nest-site selection by Sage Thrashers in southeastern Idaho

Nest sites selected by Sage Thrashers ( Oreoscoptes montanus ) in southeastern Idaho were characterized and compared with available habitat. Microhabitats within 5 m of nests had taller and more aggregated shrubs and less bare ground than the study area in general. Big sagebrush ( Artemisia tridentata wyomingensis ) plants used for nesting were taller than average ,available shrubs, had greater foliage density, were more often living, and more frequently had branches and foliage within 30 cm of the ground. Nest placement was specific with respect to relative nest height and distance from the top and perimeter of the support shrub. Sage Thrashers disproportionately used easterly exposures and underused westerly exposures for their nests.     

Seasonal microhabitat relationships of blue grouse in southeastern Idaho

Microhabitat characteristics of blue grouse ( Dendragapus obscurus ) were analyzed in breeding and wintering habitats in southeastern Idaho. Breeding habitats typically were open sagebrush ( Artemisia spp.), mixed shrub, mountain mahogany ( Cercocarpus ledifolius ) , and maple ( Acer grandidentatum ) stands on east to south facing aspects of slopes below 2100 m elevation. Breeding blue grouse selected areas with approximately a 50:50 or greater open to cover ratio. Blue grouse selected areas with higher tree coverage than available on average within the mixed shrub vegetation type. Hens with broods preferred sites with relatively tall (>50 cm) herbaceous vegetation. During autumn and winter, blue grouse preferred high elevation (>2285 m) stands of open (50% tree cover) conifer. Douglas-fir ( Pseudotsuga menziesii ) were preferred as winter roost trees. Sites selected in winter had significantly more Douglas-fir than those selected in autumn.      

Addendum to the distribution of two herptiles in Idaho

Due to an error in printing quality of an earlier article, the distribution maps for the night snake ( Hypsiglena torquata ) and the tiger salamander ( Ambystoma tigrinum ) in Idaho are reprinted.        

Some edaphic relations of southeastern Idaho wildlands

Soil samples from the Al horizon and dominant subsoil horizon at 190 sites were analyzed for Ca, Mg, K, P, and organic matter contents in conjunction with a soil resource inventory of the Caribou National Forest. Vegetative composition and production data were compared to the edaphic factors to derive relationships useful to the land manager. Organic matter was effective in distinguishing between soil orders and was positively correlated to vegetative production. Vegetative cycling of the nutrients P and K was most pronounced in soils of the order Mollisols, to a lesser degree in the Alfisols, and not at all in the Entisols. The K/Mg ratio of the soil showed a negative correlation to grass production and a positive correlation with shrub production. An interpretative table is provided to aid determinations of high versus low values for the edaphic factors studied.     

Blow flies (Diptera, Calliphoridae) of Idaho: an annotated checklist

A total of 33 species of blow flies (Diptera: Calliphoridae) are recorded from Idaho. They include 1 species each of Cochliomyia, Phormia, Protophormia, Trypocalliphora, Cyanus, Cynomya, and Melanodexia ; 12 species of Protocalliphora ; 5 species of Lucilia ; 6 species of Calliphora ; and 3 species of Pollenia . Other calliphorid species that may also occur in the state include 5 species of Protocalliphora and 3 species of Calliphora . Known distribution, periods of activity, abundance within the state, and biological notes are provided.     

Effects of grazing exclusions on rangeland vegetation and soils, east central Idaho

Nineteen exclosures on sagebrush steppe and shadscale rangelands, varying in age from 18 to 38 years, were sampled for plant species richness, plant composition, indicators of soil erosion, ground cover, vegetative cover, and herb-low shrub layer screening cover. Features within the exclosures were compared with adjacent sites of the same size that were open to grazing by livestock and wildlife. Species richness typically was slightly greater inside exclosures than in adjacent grazed sites (median = 2 more species inside exclosures), but the difference was not significant ( P = 0.16). Similarity of plant community composition between exclosures and adjacent grazed sites ranged from 45% to 82%. Evidences of soil movement, soil pedestals, and soil flow patterns were all more pronounced outside exclosures than inside ( P ≤ 0.02), even though many sites were on flat to mild slopes (median slope = 12%). Meta-analysis of the 19 exclosure sites indicated that grazing exclusion resulted in less bare ground cover compared with adjacent grazed sites ( P ≤ 0.05). The effect of grazing exclusion on visible soil surface cryptogams was significant ( P ≤ 0.05), with generally greater cover inside exclosures. Cryptogam cover differences between grazed sites and exclosures tended to increase with the number of years of grazing exclusion ( r = 0.64, P = 0.046). Pseudoroegneria spicata , a principal livestock forage, averaged greater basal cover inside exclosures than outside on 4 of 10 sites where it occurred, although no exclosure sites had greater P. spicata cover on grazed sites. Meta-analysis of the 10 sites indicated that grazing exclusion resulted in greater P. spicata cover compared with adjacent grazed areas ( P ≤ 0.05). Poa secunda , a short-growing grass that initiates growth early in the spring and is not important livestock forage, averaged greater basal cover outside exclosures on 5 of 15 sites where it occurred. Meta-analysis of the 15 sites indicated a significant treatment effect ( P ≤ 0.05), with greater Poa secunda basal cover outside exclosures. Grazing exclusion resulted in greater screening cover in the herb-low shrub layer (0-0.5 m height; P ≤ 0.05). These results indicate that despite improved livestock grazing management over the past half century, livestock grazing still can limit the potential of native plant communities in sagebrush steppe ecosystems, and that the health of semiarid ecosystems can improve with livestock exclusion in the absence of other disturbances. A few exclosure sites were similar for the measured parameters, suggesting that these sites were ecologically stable and that exclusion of livestock grazing was not sufficient to move succession toward more pristine conditions, at least within the time periods studied. Managed disturbance such as fire or mechanical brush treatments may be necessary to restore herb productivity on these ecologically stable sites.