Species-environment relationships among filter-feeding caddisflies (Trichoptera: Hydropsychidae) in Rocky Mountain streams

Species-environment relationships were determined for filter-feeding macroinvertebrates from 55 Rocky Mountain stream sites to establish species distribution patterns. Species abundance and 20 environmental variables were measured at each site with species-environment relationship determined using canonical correspondence analysis and stepwise multiple regression. Results suggest that the distribution of several taxa was strongly related to upstream-downstream environmental gradients. Arctopsyche grandis abundance increased with stream size (width and depth) and decreased with increasing turbulence (Reynolds number). Brachycentrus abundance also increased with stream size (depth). Hydropsyche abundance increased with increasing baseflow. Parapsyche elsis abundance also increased with stream size (depth). Hydropsyche abundance increased with increasing baseflow. Parapsyche elsis abundance demonstrated negative correlation with depth, Froude number, and conductivity. Taxa followed previously reported patterns, partitioning habitat according to stream size. Arctopsyche grandis , Brachycentrus , and Hydropsyche were found in larger (3rd- to 6th order) streams, while Parapsyche elsis was observed in small headwater (1st- and 2nd- order) streams. Other filter-feeding taxa such as Simulium, Pisidium and ostracods exhibited little or no apparent habitat partitioning among stream sites.     

Influence of substrate size, Cladophora , and caddisfly pupal cases on colonization of macroinvertebrates in Sagehen Creek, California

Colonization of stream macroinvertebrates onto artificial substrates was examined in Sagehen Creek, California, during 1993. Substrate size and presence or absence of pupal cases of the caddisfly Anagapetus (Glossosomatidae) were examined as possible influences on macroinvertebrate colonization. Macroinvertebrates were collected from substrates after 60 d of incubation and identified to the lowest feasible taxonomic unit. Dry weight of the filamentous green alga Cladophora also was determined for each substrate. A general linear model indicated a significant positive relationship between both substrate size and presence of pupal cases on richness ( P Anagapetus cases on Micrasema bactro , Epeorus , and Rhyacophila sp. 1, and of substrate size on Hydropsyche occidentalis and Epeorus . Neither cases nor substrate size had a significant effect on Cladophora density ( P > 0.05). There were significant negative correlations between Cladophora density and both Shannon H′ and J′ indices. There were significant positive relationships between Cladophora density with Baetis , Simulium , and Chironomidae density. Combined main effects of substrate size, Anagapetus pupal cases, and Cladophora have dynamic influences on this macroinvertebrate fauna. This study demonstrates the complex interplay of biotic and abiotic factors that determine macroinvertebrate distribution and abundance in this system.     

Composition and abundance of periphyton and aquatic insects in Sierra Nevada, California, stream

The species composition of periphyton and benthic insect communities and abundances of common taxa (&;gt;0.1&;#37; of individuals) were examined during snow-free months in Convict Creek, a permanent snowmelt- and spring-fed stream in the Sierra Nevada of California. The communities were highly diverse. The most abundant taxa in the periphyton were diatoms ( Achnanthes minutissima, Cocconeis placentula lineata, Cymbella microcephala, C. sinuata, Fragilaria construens, F. crotonensis , Navicula spp., Synedra acus , and S. rumpens ), except in late spring and summer when several seasonal blue-green algae ( Chamaesiphon incrustans, Lyngbya spp. and Oscillatoria spp.) are at their maximum densities. Most common periphyton taxa vary systematically in abundance with season, but relative abundances of taxa also appear to be influenced by streambed scouring and by concentrations of ambient nutrients. Data on population densities and length frequencies of larval and nymphal stages of common benthic insects and occurrences of pupal and adult stages were examined to determine life history patterns. Taxa hatching in winter and spring and abundant as immatures in late spring include ephemeropterans ( Epeorus longimanus, Drunella flavilinea , and Caudatella heterocaudata ), plecopterans ( Calineuria californica, Doroneuria baumanni, and Pteronarcys princeps ) and dipterans ( Cryptolabis sp.). Common taxa hatching in late spring or summer are the plecopteran Malenka ( californica? ) and the trichopterans Arctopsyche grandis and Rhyacophila acropedes . Several bivoltine and multivoltine ephemeropterans ( Baetis devinctus and B. tricaudatus ) and dipterans ( Simulium spp. and Chironomidae) have summer cohorts. Taxa hatching in late summer or autumn and most abundant in autumn include ephemeropterans ( Baetis spp., Ephemerella infrequens, Epeorus dulciana, Ironodes lepidus , and Paraleptophlebia pallipes ), trichopterans ( Hydropsyche oslari, Lepidostoma spp., Glossosoma califica, Micrasema sp., Brachycentrus americanus, Neophylax sp., and Rhyacophila vaccua ) and dipterans ( Antocha monticola, Pericoma sp., and Chironomidae). Major recurring events that may influence life history patterns and structure of the benthic insect community are (1) near-freezing, nighttime winter water temperatures and occasional anchor ice, (2) a prolonged period of high discharge in late spring and early summer (3) a brief summer, and (4) a prolonged period of moderate stream discharge in autumn when the substratum is stable and food is abundant.     

A revision of Eriogonum (Polygonaceae) subgenus Pterogonum

This revision discusses the 10 species of Eriogonum assigned to the subgenus Pterogonum. Six of the species are essentially restricted to northern Mexico; two additional species, E. hemipterum and E. nealleyi, are found primarily in Texas; and the remaining two, E. hieracifolium and E. alatum, are the most widespread species of the subgenus being found mainly in the United States and just barely entering Mexico. The subgenus is characterized by the broad, often winged or ribbed achenes, and the generally erect habit of the stems of these perennial herbs. Three new species, E. fimbriatum, E. viscanum, and E. clivosum, are described. They are related to E. ciliatum and are found in the desert foothills of north central Mexico. Two new varieties of E. atrorubens are proposed. One, var. nemorosum, is restricted to the high mountains of the Sierra Madre Occidental in northern Durango and southern Chihuahua, while the second, var. auritulum, is a plant of the Sierra Madre Oriental of Coahuila and Nuevo León. The subgenus is divided into four sections, two of which, Peregrina and Astra, are new. Cytological information is given for nearly all taxa and shows the majority of species to have a haploid number of 20. Eriogonum atrorubens var. intonsum is a polyploid with n = 40, and E. greggii is the most unusual with a haploid number of 16. Each species is described in detail, discussed, and illustrated. Distribution maps are given noting the known locations for each taxon.     

Soil and vegetation development in an abandoned sheep corral on degraded subalpine rangeland

Vegetation and soils inside and outside an abandoned sheep corral on degraded subalpine range of the Wasatch Plateau were studied to determine the influence of approximately 37 years' use of the corral on soil and plant development. Vegetal and surface cover were estimated. Herbage, litter, and soils were sampled inside and outside the corral and analyzed for C org , N, P, and S. Soil pH, bulk density, and C0 3 -C also were measured. Storage (mass/unit area) of C org , N, P, and S was determined for each component. Yield and vegetal composition were significantly affected inside the corral boundary. Herbage yield was 2.2 times greater, litter mass 16 times greater, foliar cover of grasses 2 times greater, and forb cover 70% lower inside than outside the corral. Cover of meadow barley ( Hordeum brachyantherum ), a component of the predisturbance vegetation of the Wasatch Plateau, was nearly 12 times greater inside than outside the corral. These and other vegetal and cover differences reflect inside-outside differences in concentration, storage, and availability of soil C org , N, P, and S. Concentrations of C org and total and available N, P, and S were greater in the surface 5 cm of soil inside the corral. Available P inside the corral was much higher in all soil layers. Because of bulk density differences, storage was greater inside the corral only for C org and N at 0-5 cm and for P at 5-15 cm. Lower soil pH inside the corral appears related to soil P distribution and C0 3 -C storage. Results suggest a need to reexamine earlier conclusions that tall forbs are the climax dominants of the Wasatch summer range.     

Soil-vegetation relations of recovering subalpine range of the Wasatch Plateau

Vegetation and soils inside and outside an abandoned sheep corral on degraded subalpine range of the Wasatch Plateau were studied to determine the influence of approximately 37 years' use of the corral on soil and plant development. Vegetal and surface cover were estimated. Herbage, litter, and soils were sampled inside and outside the corral and analyzed for C org , N, P, and S. Soil pH, bulk density, and C0 3 -C also were measured. Storage (mass/unit area) of C org , N, P, and S was determined for each component. Yield and vegetal composition were significantly affected inside the corral boundary. Herbage yield was 2.2 times greater, litter mass 16 times greater, foliar cover of grasses 2 times greater, and forb cover 70% lower inside than outside the corral. Cover of meadow barley ( Hordeum brachyantherum ), a component of the predisturbance vegetation of the Wasatch Plateau, was nearly 12 times greater inside than outside the corral. These and other vegetal and cover differences reflect inside-outside differences in concentration, storage, and availability of soil C org , N, P, and S. Concentrations of C org and total and available N, P, and S were greater in the surface 5 cm of soil inside the corral. Available P inside the corral was much higher in all soil layers. Because of bulk density differences, storage was greater inside the corral only for C org and N at 0-5 cm and for P at 5-15 cm. Lower soil pH inside the corral appears related to soil P distribution and C0 3 -C storage. Results suggest a need to reexamine earlier conclusions that tall forbs are the climax dominants of the Wasatch summer range.     

A checklist of the alpine vascular flora of the Teton Range, Wyoming, with notes on biology and habitat preferences

A checklist of the vascular flora of the alpine zone (treeless vegetation above 9500 feet or 2900 m) of the Teton Range is presented. For each of the 216 species, six attributes are listed: flower color and shape, pollination mode, life form, habitat preference, and whether each species is found in the Arctic. White and yellow flowered species are most common, and zoophilous species greatly predominate over anemophilous and apomictic species. Perennial/biennial herbs are the most common life form. Common habitats in the alpine zone include dry and wet meadows, bogs, debris accumulations, and cliffs and rock faces. Arctic species account for 25.9 percent of the flora. The 216 species are distributed among 111 genera and 36 families. The largest families, in order of size, are Asteraceae, Poaceae, Cyperaceae, Brassicaceae, Rosaceae, and Scrophulariaceae.     

Helminth parasites of cats and dogs from central Utah

A survey of the helminth parasites of 100 stray cats and 50 dogs was conducted. Each host was euthanized, and the internal organs were excised and examined for parasites. Helminths identified from cats included the tapeworms Dipylidium caninum and Hydatigera taeniaformis, and the nematodes Physaloptera sp. and Toxocara mystax. Two species of coccidia, Isospora felis and I. rivolta, and one ectoparasitic mite, Cheyletiella parasitivorax, were also recovered from cats during sugar flotation of the feces. Helminths identified from dogs included the tapeworms D. caninum, Taenia hydatigena, T. krabbei, and T. pisiformis, and the nematodes Filaroides milksi, Toxascaris leonina, and Toxocara canis. Of those parasites collected, D. caninum, T. canis, and T. mystax are known to cause accidental infection in humans and could represent potential health hazards in this region.     

XXIX.—On the generic names of the rupicaprine ruminants known as Serows and Gorals

Summary

A detailed illustrated account of the nervous system in S. gregaria is given. The central, peripheral and sympathetic nervous systems have been described. The central and peripheral nervous systems comprise the brain, ventral nerve cord, suboesophageal, three thoracic and five abdominal ganglia and their nerves to different parts of the body. The brain consists of proto, deuto and tritocerebrum. The suboesophageal ganglion lies below the oesophagus and is connected to the tritocerebral lobes by a pair of connectives. This ganglion gives off a pair of recurrent nerves and seven pairs of nerves supplying the mouthparts, cervical muscles, salivary ducts and prothoracic ventral longitudinal muscles. The first or prothoracic ganglion gives off a pair of recurrent nerves and five pairs of nerves supplying different prothoracic muscles, sensillae of the prosternum and forelegs. The second or mesothoracic ganglion also gives off a pair of recurrent nerves and five pairs of nerves innervating hypodermis, forewings, middle legs, different muscles of the mesothorax and the chordotonal organ. The third or metathoracic ganglion gives off five pairs of metathoracic nerves and six pairs of abdominal nerves; the thoracic nerves supply the hindwings, metasternal sensillae, various muscles and hindlegs while the abdominal nerves include dorsal and ventral nerves of the first, second and third abdominal segments supplying the abdominal muscles, pleuron, tympanum and spiracles. The dorsal nerves of the second to eighth abdominal segments form VNABIC which supply the lateral muscles and spiracle in the respective segment. The first four abdominal ganglia, i.e. fourth, fifth, sixth and seventh abdominal ganglia give off one dorsal and one ventral nerve supplying the dorsal and ventral muscles in the respective segment. In the female the ventral nerve of the seventh abdominal ganglion also innervates the oviduct. The eighth abdominal ganglion gives off six pairs of nerves which supply the muscles of the eighth, ninth and tenth abdominal segments, epiproct, paraproct, cerci and rectum. This ganglion in the male also supplies the complex genital organ and in the female sends nerves to different valves of the ovipositor. The sympathetic nervous system is divisible into stomatogastric nervous system consisting of frontal ganglion, oesophageal ganglion, hypocerebral ganglion and their nerves and ventral sympathetic nervous system comprising a single median nerve, transverse nerves and paramedian nerves.     

Temporal patterns of seedling emergence and early survival of Great Basin perennial plant species

We seeded Agropyron cristatum and 16 native Great Basin perennial species on Bromus tectorum -dominated sites to compare temporal patterns of seedling emergence and early survival among species. To indicate variability between sites and between years, plots were planted on 2 sites in western Utah in autumn 1994, and plantings were repeated near 1 site in autumn 1995. Two sites included burned and unburned seedbed treatments. We monitored seedling emergence and survival from early winter until July of the 1st year. Four seasonal patterns of emergence were evident, indicating considerable potential for different seasonal patterns of precipitation to favor recruitment of difference species. Emergence of all shrubs, except Ephedra nevadensis , began in February and essentially ended by April. Seedlings of Ephedra nevadensis and of the grasses Agropyron and Pseudoroegneria spicata emerged over an extended period from February through June. Most other grasses and the 2 forbs began emerging in April and continued into June. Pleuraphis jamesii emergence did not begin until May. Although many seedlings of the 3 chenopod shrubs emerged, none survived, suggesting their episodic recruitment is more a function of survival than of emergence. Survival of 2 Chrysothamnus species was also low. Pseudoroegneria and Agropyron had the highest numbers of seedlings surviving on the moister site, followed by Elymus elymoides and Stipa comata . Survival of Agropyron , but not the native Elymus , was more depressed on the drier of the 2 sites planted in 1994. Stipa, Oryzopsis hymenoides , Pleuraphis , and Ephedra survived as well on the drier site as on the moister site, or better. On the 1995 planting sites Bromus was greatly reduced by the burn treatment, and, in contrast to the effect of burn treatments on the 1994 site, survival of all species except Oryzopsis and Ephedra was higher on burned than on unburned treatments. Overall, Stipa, Oryzopsis , and Pleuraphis had low emergence but consistently higher survival.     

Tree growth and regeneration response to climate and stream fow in a species-rich southwestern riparian forest

We studied the influence of climate variables, stream flow, and topography on regeneration and growth of several riparian tree species ( Acer negundo, Alnus oblongifolia, Fraxinus velutina, Juglans major, Platanus wrightii, Populus fremontii, Salix spp.) at an unregulated perennial stream, West Clear Creek, in central Arizona. A pulse of seedling regeneration occurred for Alnus, Fraxinus, Platanus, Populus , and Salix in 1995 and 1996 following high winter and spring surface flows in 1993 and high spring surface flow in 1995. In contrast, little regeneration occurred for Acer and Juglans under these conditions. Most seedlings occurred at the active channel topographic location, and few seedlings occurred at abandoned channel, gravel-boulder bar, and bench locations. Relationships between environmental variables and annual radial stem growth varied among species and between constrained and unconstrained reaches. High spring or winter surface flows were negatively related to growth of Acer, Alnus, and Platanus , whereas high spring surface flow was positively related to growth of Fraxinus . Positive relationships between precipitation and growth occurred only for Fraxinus and Juglans , suggesting greater use of surface soil water by these species. Annual radial growth was high for Platanus and Alnus, medium for Acer and Fraxinus, and low for Juglans . Overall, the tree species in our study responded individually, rather than collectively, in regeneration and growth to changes in stream flow and climatic variables.     

Parasites of the bowhead whale, Balaena mysticetus

Blood, tissue, and organ samples from five bowhead whales were examined for ecto- and endoparasites. Two species of protozoans, four genera of diatoms, one species of trematoda, two species of nematoda, and one species of amphipoda "louse" were found. No blood parasites were recovered. The larval anisakid nematode, found in the submucosa of the forestomach of one whale, generated a prominent inflammatory response. Protozoans found in contents of the colon included a flagellate and a sarcodinan. The sarcodinan, which was common in the colon contents of one whale, belongs to the genus Entamoeba and probably represents an undescribed species. Ogomogaster plicatus , a trematode, was also identified. The data from this study are compared with previous lists of parasites for the bowhead whale and two other species of baleen whales. From the results presented, the previous list of parasites for the bowhead whale has been expanded to include eight additional genera and species.     

Helminth parasites of the white-tailed jackrabbit, Lepus townsendi, from northwestern Colorado and southern Wyoming

Helminth parasites of white - tailed jackrabbits, Lepus townsendi , were surveyed from southern Wyoming and northwestern Colorado. A total of eight helminth species were identified, including two species of adult cestodes, Mosgovoyia pectinata and M. varabilis ; three species of larval cestodes, Multiceps serialis , Taenia pisiformis , and Taenis sp. ; and three species of nematodes, Dermatoxys veliger , Passalurus ambiguus , and a filariid, Micipsella brevicauda . In addition, eggs of an unidentified species of Nematodirus were found in pooled fecal samples. The cysticercus larva of Taenia sp. is a species new to science and will be reported elsewhere. Mosgovoyia varabilis and Micipsella brevicauda are new records for the white - tailed jackrabbit.         

Ecological differences of C 3 and C 4 plant species from central Utah in habitats and mineral composition

Six study sites were established in each of three community life form types (grass, forb, and shrub) containing as dominants or subdominants either C 3 and/or C 4 plants. Soil and vegetation samples were analyzed for total nitrogen, phosphorus, magnesium, calcium, potassium, sodium, zinc, iron, copper, and manganese. Discriminant analysis and analysis of variance statistics were used to evaluate differences in mineral content of soils and plant tissues. C 4 plants in all study sites assimilated higher concentrations of potassium, iron, and calcium than did C 3 plants. Forbs in all sites contained the highest concentrations of minerals, followed by shrubs and grasses.     

Riparian vegetation along the middle Snake River, Idaho: zonation, geographical trends, and historical changes

A baseline study was conducted on an 83-km free-flowing reach of the Snake River between Swan Falls Dam and the Idaho-Oregon border. The research had 2 components: (1) field characterization and inventory of existing riparian flora, vegetation, and environment (soils, topography, streamflow), and (2) determination and mapping, using a geographic information system, of historic changes in riparian vegetation based on a time series (1938-39, 1957, 1969, 1987) of aerial photographs. The flora was diverse, with 185 species of vascular plants identified, 63 of which were exotics. Vegetation was structured vertically along the riverbank gradient into lifeform-defined habitat types: emergent, riparian shrub-forb, tree, transitional grass-shrub, and upland. Riverbank seepage, probably of agricultural origin, blurred zonation patterns on some sites and added species to the overall flora. Upstream-downstream differences existed in the physical characteristics and vegetation of river subreaches. Coverage of riparian woodland, island riparian and total riparian vegetation, and area of islands increased since the 1930s, with the greatest changes in the 1969-1987 interval. Possible contributing facts were (1) significant declines in annual minimum flows since the 1950s, (2) decreases in peak flows following the completion of Swan Falls Dam and some upstream dams since the 1920s, (3) introduction and spread of exotic tree species ( Elaeagnus angustifolia and Tamarix spp.) and (4) possible effects of intensive agriculture on river sediment load and soil nutrients. The introduction and proliferation of purple loosestrife ( Lythrum salicaria ) could have considerable future effects on vegetation-channel dynamics in the middle Snake River.     

Phylogenetic implications of the structure and distribution of ovipositor valvilli in the Hymenoptera (Insecta)

Valvilli, articulated chitinous flaps on the lower ovipositor and sting valves in certain Hymenoptera, were studied using light and electron microscopy. Presence or absence, number, position and structure of valvilli in the ovipositors of more than 300 species distributed among 31 families (including representatives of 74 subfamilies of Ichneumonoidea) have been examined. Valvilli were found to occur in most Ichneumonoidea and most families of the aculeate lineage. Valvilli were absent from the Symphyta, Trigonalyoidea, Stephanoidea, Evanioidea, Cynipoidea, Chalcidoidea, Proctotrupoidea, Megalyroidea and Ceraphronoidea. Aculeates have a complex, double valvillus, which differs considerably in structure from those found in the Ichneumonoidea. Within both the Ichneumonidae and Braconidae the number and the position of the valvilli appear to be phylogenetically significant. Within the Braconidae, in particular, valvillus structure varied between subfamilies. The implications of valvillus distribution and structure in the Hymenoptera as a whole and within the Ichneumonoidea are discussed.     

Composition and distribution of the milliped tribe Pachydesmini west of the Mississippi River (Polydesmida: Xystodesmidae)

The xystodesmid milliped tribe Pachydesmini is supported by the autapomorphic absence of bold aposematic pigmentations and possibly also by relative somatic inflexibility; it comprises 3 component genera: Pachydesmus Cook, 1895; Dicellarius Chamberlin, 1920; and Thrinaxoria Chamberlin and Hoffman, 1950. Three representatives occur west of the Mississippi River— P. clarus (Chamberlin), P. crassicutis crassicutis (Wood), and T. lampra (Chamberlin). New localities are documented in Louisiana and Texas, and literature records are summarized for these states and Arkansas; records of P. clarus from Cherokee County, Texas, are the westernmost in this state for the east-Nearctic xystodesmid fauna. An apparently allopatric population of P. crassicutis crassicutis occurs in Evangeline and Lafayette Parishes, Louisiana. These are the first records of this species from west of the Mississippi River, and new localities of this form are cited from east of the watercourse. Thrinaxoria lampra , known previously in Texas from only Gregg County, is documented from Bowie, Cass, Harrison, Rusk, Sabine, and Titus Counties plus Webster Parish, Louisiana. Diagnoses and pertinent anatomical illustrations are provided for each species including the first cyphopod drawings for P. clarus and T. lampra ; occurrences west of the river are depicted on a map. A new tribal diagnosis is published along with a distribution map.     

Form and dispersion of Mima mounds in relation to slope steepness and aspect on the Columbia Plateau

Patterned ground consisting of Mima-type earth mounds and associated sorted stone circles and nets is widespread on the Columbia Plateau of western North America. Studies of the geometric relationships of mounds and stone nets to slope aspect and steepness were carried out at the Lawrence Memorial Grassland Preserve, north central Oregon in June 1987. Mound and moundfield characteristics were sampled on randomly chosen 1-ha plots on slopes of different aspect and steepness. Mounds were largest, most circular and symmetrical in form, and most fully encircled by beds of size-sorted stones on level sites. On slopes of increasing steepness, mounds decreased in size, showed increasing asymmetry and downslope elongation, and became connected into lines oriented up- and downslope. Encircling stone beds became more weakly developed or disappeared on upslope and downslope sides of the mounds, and the lateral beds developed downslope extensions that eventually merged with those of adjacent upslope and downslope mounds. These patterns are interpreted as reflecting changes in the manner of soil translocation by northern pocket gophers, Thomomys talpoides , due to their responses to tunneling on slopes and to the modification of the flow of water across the slope because of the presence of mounds.     

Description of the immature stages of Sigara (Tropocorixa) santiagiensis (Hungerford, 1928) (Insecta: Heteroptera: Corixidae)

The immature stages of Sigara santiagiensis are described and illustrated for the first time. The eggs of Sigara can be distinguished by the chorionic surface. The main characters separating the five nymphal instars of S. santiagiensis are: body and head lengths; body, head and eye widths; ocular index; numbers of transverse sulcations of the rostrum, setae on the inner surface of protibiotarsus, campaniform sensilla on posterior surface of protrochanter, spines on posteroventral surface of mesotibia and on tibial comb of metaleg, long, slender setae on posterodorsal surface of mesotarsus, spines and swimming hairs on anteroventral and posterodorsal surfaces of metatarsus; and grade of development of the wing pads. The body length, the chaetotaxy of the mesonotum, profemora and metafemora, protibiotarsus, metatibia, metatarsus and urosternites distinguish species or group of species of instars I and V of some of the species of the genus Sigara described up to now.