Autumnal migration of Eared Grebes ( Podiceps nigricollis ) through southwestern Wyoming: a key to assessing the size of the North American population

In autumn the vast majority of the North American population of Eared Grebes ( Podiceps nigricollis ) congregates for several months at Great Salt Lake, Utah, and Mono Lake, California. Because the lakes are so large, it has not been possible to monitor grebe migration with sufficient accuracy to determine when peak numbers are reached. To clarify migration phenology, we analyzed data from 2 isolated wetland areas in southwestern Wyoming where grebes land en route between breeding areas in the interior and Great Salt Lake. Occasional birds, probably nonbreeders or failed breeders, begin moving southward as early as mid-June. Migration of postbreeding birds starts in late July, peaks in late August and September, and is largely completed by the end of October, with very small numbers arriving into November. The pattern of migration and number of birds encountered varied annually, but 95% of the migration was usually completed by 15 October. As a result, censuses at the major staging lake made on or after 15 October but before the grebes depart for wintering areas can be used to study trends in size of the North American population.     

Barn owl diet includes mammal species new to the island fauna of the Great Salt Lake

An investigation of the diet of the Common Barn-owl ( Tyto alba ) on Antelope Island, Great Salt Lake, Utah, yielded four mammal species not previously known to occur on any island in the Great Salt Lake ( Microtus pennsylvanicus, M. montanus, Ondatra zibethicus , and a Sorex sp.). Two other species, known from other islands, were added to the list of fauna of Antelope Island ( Perognathus parvus and Reithrodontomys megalotis ). The barn owl diet on Antelope Island was remarkably like that of barn owls feeding in farmlands adjacent to the Great Salt Lake despite major vegetational differences.     

Response of nesting waterfowl to flooding in Great Salt Lake wetlands

Great Salt Lake wetlands were inundated in 1983, displacing approximately 20,000 nesting waterfowl. Ten protected marshes in the Great Basin were surveyed for changes in numbers of breeding pairs of waterfowl during each of four years preceding Great Salt Lake flooding and four years following flooding. The hypothesized increase in numbers of breeding birds did not occur, indicating that flood-displaced waterfowl did not move into nearby suitable habitat to nest.     

Symbiotic associations between hermit crabs and bryozoans from the Otago region,southeastern New Zealand

Thirteen species of bryozoans (six cyclostomes and seven cheilostomes) occurring off the Otago Peninsula (southeastern New Zealand) form symbiotic, possibly mutualistic, associations with hermit crabs. For all but one of these bryozoan species, such an association has not been reported previously. At most only 3 of the 13 bryozoans are obligate symbionts of hermit crabs. Associations are apparently initiated when a bryozoan larva settles on a gastropod shell occupied by a juvenile hermit crab and develops to form a colony which encrusts the whole shell and then continues to grow out beyond the shell aperture in the form of a helicospiral tube. The tube-building bryozoan colony grows in step with the crab, and tube development appears to be controlled by crab morphology and activity. Of the six species of hermit crabs found occupying bryozoan tubes, four were regular tube occupants, although they could also be found in other shelter types. Hermit crabs occupying bryozoan tubes very rarely indulged in shell exchanges or shell fights. There appear to be no clear cut pairwise correlations between hermit crab species and tube-forming bryozoan species. The following bryozoan species are described for the first time: Heteropora parapelliculata, Borgiola otagoensis, Disporella gordoni, Osthimosia monilifera and O. socialis.     

Breeding ecology of Long-billed Curlews at Great Salt Lake, Utah

We qualified nest site characteristics, breeding densities, and migratory chronology of Long-billed Curlews at the Great Salt Lake, Utah. The species is apparently declining in Utah, and little is known about their breeding in the eastern Great Basin Desert. This study was designed to provide wildlife biologist with the baseline data useful for their successful management. Curlews arrived in northern Utah in late March and generally departed by mid-August. Nest densities at Great Salt Lake ranged from 0.64 to 2.36 males/km 2 . The habitat at curlew nest sites consisted of significantly shorter vegetation than nearby random locations ( ˉx = 5.7 versus 9.0 cm, respectively; P < .01). Nests tended to be located in small patches of vegetation near barren ground. Maintenance of relatively short vegetation appears to be important in managing curlew habitat. In addition, only 2 of 10 nests we monitored in 1992 were successful, with most lost to mammalian predators. Further research is needed to determine impact of mammalian predators on curlew populations.     

Shell condition and adequacy of three sympatric intertidal hermit crab populations

Shell use in relation to size adequacy and presence of physical damage and encrustation was evaluated and compared among and within three co-existing species of intertidal hermit crab (Clibanarius antillensis, C. sclopetarius and C. vittatus) in the intertidal region of Pernambuco Islet, São Sebastião Channel, south-eastern Brazil. Comparisons of shell utilization patterns among species and sexes were made with respect to physical damage (perforations and breakage in aperture and apex), encrustation by other organisms and shell size adequacy. Two adequacy indices were calculated. The visual adequacy index (VAI) was based on the degree of hermit crab retraction into the shells (1 = crab totally retracted and 6 = shield exposed). The shell adequacy index (SAI) was calculated through a comparison of the weight of the used versus the preferred shell. A relationship was found between VAI and SAI with crabs assigned as VAI = 3 occupying optimal shells (SAI = 1), i.e. crabs that could retract and those that could not retract the whole body into shells were in relatively heavier and lighter shells than the preferred ones, respectively. Shells utilized by the hermit crabs were generally undamaged and highly encrusted (except for C. antillensis) by oysters, barnacles and green algae, features that may reduce the risks of desiccation and predation. The frequent damage to the shell apertures was associated with a high abundance of shell-crushing predators in the studied area. The degree of encrustation as well as the shell adequacy (VAI and SAI) showed intra- and interspecific variation, while the presence of damage differed only among sexes (reproductive classes). In general, the smallest individuals in the populations used relatively heavier shells. Fecundity of the crabs of this assemblage is thought not to be limited by shell use once ovigerous females are occupying optimal shells.     

Insular biogeography of mammals in the Great Salt Lake

The distribution of 21 species of nonvolant mammals among nine islands in the Great Salt Lake was analyzed for biogeographic patterns. The number of species inhabiting an island is closely correlated with island area That the slope of the regression line describing this relationship (z or b) is relatively shallow compared to (1) totally isolated island systems or (2) island systems where an equilibrium between rates of colonization and extinction have been attained suggests that isolation plays little role in accounting for the variation in mammalian species diversity among islands. Stepwise multiple regression confirms this, while demonstrating that area alone accounts for 88 percent of the variation in species diversity among islands. However, endemic subspecies comprise a significant proportion of the insular mammalian fauna, suggesting that isolation for small mammals restricted to certain habitats may be substantial. A general scenario of the processes determining insular mammalian diversity and endemism is discussed for the Great Salt Lake, where the dynamic lake level creates a potential for different biogeographic processes over time.     

Utah Chub ( Gila atraria ) from the latest Pleistocene Gilbert Shoreline, West of Corrine, Utah

A bulk sampling of gastropods collected near Great Salt Lake, Utah, Revealed several fish bones of Gila atraria (Girard). The early date of this find, coupled with the relationship of the Gilbert lake transgression and successive regression of approximately 11,000 years B.P., reveals a death assemblage induced by a series of saline inundations into the freshwater paludal environment.     

Three new records for diatoms from the Great Basin, USA

Three diatom species recently collected from Great Basin localities represent new records of these taxa from this region of western North America. Cocconeis scutellum &nbsp; Ehr. and Melosira dubia &nbsp; Kuetz. were collected from a thermal spring in Tooele County, Utah. Nitzschia hustedtiana &nbsp; Salah was collected from newly flooded marshes at the south end of the Great Salt Lake, Tooele Countv, Utah.     

A summary of biological investigations concerning the Great Salt Lake, Utah (1861-1973)

The early stages in the history of biological investigation of the Great Salt Lake involved the identification and establishment of taxonomic relationships of the indigenous flora and fauna. A result of advancements in systematic biology is that many of the earlier names of organisms have been placed in synonomy. Recent interest in the lake has centered on biological productivity and interactions of components of the ecosystem. The creation of two ecologically distinct lakes by the construction of a railroad causeway has further enhanced the biological complexity of what was originally believed to be a lifeless body of brine. &nbsp;     

Inventory of Utah crayfish with notes on current distribution

Crayfish distribution and composition in Utah are poorly documented. Based upon limited collections, the native Pacifastacus gambelii is widespread and often abundant in the Bear and Weber river drainages and is occasionally represented in smaller tributaries to the Great Salt Lake and to the Raft River. Pacifastacus leniusculus was collected from Utah County and Procambarus clarkii from Tooele County; the origin of these populations is not known. The nonnative crayfish Orconectes virilis is currently abundant in the Virgin, Price, and Duchesne river basins and the Glen Canyon, Flaming Gorge, Deer Creek, and Starvation reservoirs; it is expanding in Huntington North, Scofield, and Willard reservoirs. Further work is required to develop a more complete inventory and monitor the impacts on aquatic ecosystems of expanding nonnative crayfish populations. Surreptitious stockings can be dealt with only if the public is made aware of the adverse consequences of ill-conceived introductions.     

Taphonomy and significance of Jefferson's ground sloth (Xenarthra: Megalonychidae) from Utah

While a variety of mammalian megafauna have been recovered from sediments associated with Lake Bonneville, Utah, sloths have been notably rare. Three species of ground sloth, Megalonyx jeffersonii, Paramylodon harlani, and Nothrotheriops shastensis , are known from the western United States during the Pleistocene. Yet all 3 are rare in the Great Basin, and the few existing records are from localities on the basin margin. The recent discovery of a partial skeleton of Megalonyx jeffersonii at Point-of-the-Mountain, Salt Lake County, Utah, fits this pattern and adds to our understanding of the distribution and ecology of this extinct species. Its occurrence in Lake Bonneville shoreline deposits permits a reasonable age determination of between 22 and 13 ka.     

Birds of Gunnison and Cub islands, Great Salt Lake, Utah

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} A total of 87 avian species were recorded on islands of Great Salt Lake by Behle, with 17 observed on Gunnison and Cub islands. This paper presents sightings and salvaged carcasses recorded on Gunnison and Cub islands, 1972 &ndash; 1974. Of the 112 species observed, 95 are first records for Gunnison and Cub islands and 49 are first records on or near any island of Great Salt Lake. Over 90 percent of species observed on the islands were transients.     

Gastropod shell utilisation pattern by the hermit crab Clibanarius symmetricus (Anomura: Diogenidae) in an Equatorial Amazon estuary

Clibanarius symmetricus is a diogenid hermit crab that is highly abundant in rocky intertidal environments, including the rock outcrops of Amazon estuaries. This study characterises the C. symmetricus shell utilisation pattern in the Marapanim River estuary, Pará, Equatorial Amazon, based on the hypothesis that occupancy patterns would differ, in relation to biometry and diversity of occupied shells, from those of other regions in the range of this species due to the distinct and unique environmental characteristics of equatorial estuaries. Monthly samplings were carried out from August 2006 to July 2007, in the upper and lower areas of the mid-littoral during low tides. A total of seven gastropod species were found as shells occupied by hermit crabs: 93.33% were Thaisella trinitatensis shells, 2.00% Nassarius vibex, 2.00% Neritina virginea, 1.33% Natica marochiensis, 0.67% Parvanachis obesa, and, occasionally, Littorina flava and Phalium granulatum shells, each with only one occurrence (0.33%). Juveniles [cephalothoracic shield length (CL) of less than 3.6 mm] occupied a higher variety of shells, while adults occupied shells with larger meristic variation. Males occupied larger shells. The length of the animal was influenced by shell measurements (total width, aperture width and weight). Clibanarius symmetricus showed occupancy patterns generally similar to those of specimens of the same species previously studied in the Brazilian subtropical region, and this occupancy is explained by shell availability, shell size and weight, and hermit size. However, this study showed lower occupied shell species diversity, and the species with highest occupancy frequency (T. trinitatensis) was not reported in any previous studies on this hermit crab. In addition, the studied population differed in occupancy patterns, with differences between males and females, and between juveniles and adults.     

Cattail decline at Farmington Bay Waterfowl Management Area

For the last seven years, 1969 to 1976, a steady decline of cattails ( Typha latifolia L.) has been observed at Farmington Bay Waterfowl Management Area, Davis County, Utah. Several parameters of Farmington Bay's environment that could cause or enhance a decline of the marshland vegetation were studied. These parameters included temperature, pH, phenols, oil and grease, heavy metals, fungus pathogens, and salt water intrusion from the Great Salt Lake. Elevated soluble salt concentrations were found to be responsible for the decline. Cattails are weakened or killed when they are exposed to soluble salt concentrations greater than 5.0 gm/liter, and there is a significant (1 percent level) negative correlation ( - 0.68) between soluble salt concentration and cattail height. Symptoms of elevated salt concentrations include stunted growth, leaf tip necrosis (burning), and occasional browning of an entire cattail clone. Furthermore, those salt concentrations that cause physiological stress in cattails also facilitate the growth of a decomposition fungus, Chaetophoma confluens. This fungus causes a rot consisting of irregularly scattered lesions on the surface of the rhizomes and was consistently isolated from rhizomes of declining plants. &nbsp;     

The hermit crab Sympagurus dimorphus (Anomura: Parapaguridae) at the edge of its range in the south-western Atlantic Ocean: population and morphometry features

Sympagurus dimorphus is one of the 12 hermit crab species recorded for Argentinean waters. Despite the high abundance registered in some scallop fishing grounds, its biology remains little known. In the present study, we analysed some population features of S. dimorphus living in symbiosis with Epizoanthus paguricola from a series of samples taken in the Argentine Sea, south-western Atlantic Ocean. Our results showed that S. dimorphus was commonly found from 40ºS to lower latitudes, in a patchy distribution along the shelf-break front. The overall sex ratio was 1:1. The smallest ovigerous female measured 6 mm in cephalothoracic shield length and this size was used as parameter to define the size of juveniles. The sex ratio size class pattern corresponded to Type IV or anomalous curve. S. dimorphus is a dimorphic species, as evidenced by the larger size of the males and the positive allometric growth of the right cheliped. The species also showed asymmetry, with the left uropod always larger than the right one. To the best to our knowledge, this is the first report on population features and relative growth for a member of the genus, based on long-term sampling. This species presents a patchy distribution along the shelf-break of Argentina. Its density tended to decrease over the five-year sampling period regarding the recruitment of hermits associated with colonies of zoanthids. In addition, the relatively homogeneous nature of this refuge does not seem to influence the growth of the hermit crab, which presents sexual dimorphism in relation to the sex/size conditions.     

In memoriam: Seville Flowers (1900-1968)

Seville Flowers was the foremost authority of his time on cryptogamic botany in the intermountain region, having published monographs on the mosses, lichens, and ferns of Utah. He also had strong interests in algae, grasses, composites, and the history of botany. In addition to his systematic research, his expertise extended to field ecology. Early in his career he made a classic study of the vegetation of the Great Salt Lake region that led in later years to his participation in the ecological studies at Dugway Proving Grounds in western Utah. Still later he had charge of the predam vegetative surveys of several reservoir sites along the Upper Colorado River, including Glen Canyon, which was later submerged under Lake Powell. He served as professor of botany at the University of Utah from 1936 to 1968. His professional career started in 1929. A bibliography of his writings is included in this account of his life and professional career.&nbsp;     

Behavioral and physiological responses of Eared Grebes ( Podiceps nigricollis ) to variations in brine shrimp ( Artemia franciscana ) densities

Eared Grebes ( Podiceps nigricollis ) use the Great Salt Lake (GSL) primarily as a fall staging area. They feed on brine shrimp ( Artemia franciscana ) to build up energy reserves to complete their southward migration. Whereas it has been speculated that timing of grebe departure from the GSL is due to declining shrimp density, this hypothesis has not been tested. We monitored grebe weight, behavior, and departure dates to test this hypothesis and to determine the effects of declining shrimp densities on Eared Grebes during 1999, 2000, and 2001 when there were different shrimp densities. Despite differences in shrimp densities, grebes left the GSL about the same time each year. Juvenile and subadult mass was significantly lighter ( P P > 0.05) in dive or surface duration between 1999 and 2000, there were differences in the percentage of time spent foraging. Our results indicated that at shrimp densities ?1 , grebes increased their foraging effort to offset the declining food resource instead of departing the GSL at an earlier date.     

Larval development and emigration behaviour during sea-to-land transition of the land hermit crab Coenobita brevimanus Dana, 1852 (Crustacea: Decapoda: Anomura: Coenobitidae) under laboratory conditions

To determine the early life history of the land hermit crab Coenobita brevimanus Dana, 1852, larvae were cultured individually in the laboratory. The zoeal and the megalopal stages are described and illustrated. The larvae developed through four planktonic zoeal stages to the megalopal stage. The major differences in the zoeal characters between C. brevimanus and other described Coenobita species were found in the armature of the pleomeres, whereas the character of pleomeres of C. brevimanus zoeae is the same as that of the coconut crab Birgus latro, a different genus in the same family. Morphological similarity was also found in segmentations of antennules and antennae in megalopae between C. brevimanus and the coconut crab. Megalopae of C. brevimanus were cultured in containers holding seawater and a hard substrate. These crabs migrate from the sea to land after developing a habit of acquiring gastropod shells.     

Description of a new species of Asymmetrione (Isopoda: Bopyridae: Pseudioninae) infesting the hermit crab Paguristes tomentosus (Anomura: Diogenidae) from Peru,with a key to species and a review of southeastern Pacific bopyrids

A new species of bopyrid isopod is described from a host hermit crab Paguristes tomentosus collected from Pisco, Peru and assigned to the pseudionine isopod genus Asymmetrione Codreanu, Codreanu and Pike, 1965. This is the second species in the genus with less than 20° asymmetry in females, but agrees with all other species in the genus in having the characteristic “socket” on the propodus of the female's pereopods, and in all characters of the males. A key is provided to the 10 species now in Asymmetrione. New records of an Anathelges sp. from Pagurus villosus collected in central Chile are given but additional material is required to determine whether these specimens represent the eastern Pacific A. thompsoni or the western Atlantic A. hyptius. A review of all the bopyrid species known from the western South American coast, with remarks on their taxonomy and biology, is provided.