The Simuliidae (Diptera) of the River Oder and its tributaries,with special reference to the re-appearance of Simulium (Schoenbaueria) nigrum (Meigen) in larger rivers in Central Europe

An investigation was carried out over a five-year period into the blackfly fauna of one of the most important rivers of the North-Central European lowlands, the Oder, together with its major tributaries (Nysa, Stobrawa, O?awa, Barycz, Bobr, Kroisa, Lausitzer Neisse, Warta, Notec), from its source in the Oder Hills to its mouth in the Baltic Sea. Thirteen species were found. The two dominant indicator species, Simulium (Simulium) reptans (Linnaeus) and Simulium (Schoenbaueria) nigrum (Meigen), develop populations of plague proportions within this catchment area. Blackflies of the subgenus Schoenbaueria Enderlein have not been found in Germany or Poland for more than 70 years. However, since 1997, the species S. (Sch.) nigrum was found in the River Oder in enormous numbers together with S. (S.) reptans, and in the vicinity of their breeding sites in Poland and eastern Germany both species are serious pests of man and grazing animals. Notes are given on the biology, distribution and habitat preferences of S. (Sch.) nigrum. The paper concludes with a comparison of the River Oder with some other Central European rivers in respect of its blackfly fauna, together with data on the phenology of the two indicator species.     

Biogeography and physiological adaptations of the brine fly genus Ephydra (Diptera: Ephydridae) in saline waters of the Great Basin

Four species of the genus Ephydra are commonly found in saline waters within the hydrologic Great Basin: E. hians, E. gracilis, E. packardi , and E. auripes . Though none of these brine flies is endemic (distributions also occur outside the Great Basin), they all inhabit distinctive habitat types and form the characteristic benthic insect fauna of inland saline-water habitats. The affinities of each species for different salinity levels and chemical compositions, and ephemeral to perennial habitats, appear to form the basis for Biogeographic distribution patterns. Within any habitat, changing salinity conditions over time may impose physiological or ecological constraints and further alter patterns of population productivity and the relative abundance of co-inhabiting species. Based on the physiology of salt tolerance known for these species, high salinity conditions favor E. hians in alkaline water and E. gracilis in chloride water. At lower salinities, based on limited habitat data, E. auripes and E. packardi are often more common, again showing respective preferences for alkaline and chloride chemical conditions. Specialized adaptations for alkaline carbonate waters are found in the larval Malpighian tubule lime gland of the alkali fly E. hians , while high salt tolerance in E. gracilis appears to be conferred by high hemolymph osmolality. Adaptation to ephemeral and low salinity conditions may be accomplished by swift adult colonizing ability and rapid larval development rates. It is hypothesized that adaptive specialization in both physiology and life history and varied geochemistry of saline water habitats across the Great Basin produce the Biogeographic pattern of distributions for species in this genus. This perspective on the genus Ephydra , and possibly other biota of mineral-rich Great Basin waters, suggests that interconnections among pluvial lakes may be less relevant to aquatic biogeography than chemical profiles developing in remnant lakes and ponds with the progression of arid post-pluvial climatic conditions.     

Relation of fish communities to environmental conditions in urban streams of the Wasatch Front, Utah

Twenty-eight sites along the Wasatch Front, north central Utah, representing the range of urban land use intensity for wadeable streams of the area, were sampled in September 2000. Fish communities were assessed by single-pass electrofishing, and physical habitat and water-quality characteristics were measured. On average, nonnative species comprised 54% of species richness and 53% of relative abundance, although only Salmo trutta and Pimephales promelas were very abundant at any 1 site. Salmo trutta and Catostomus platyrhynchus , a native species, were the most widely distributed and abundant species captured. Analysis of fish communities using nonmetric multidimensional scaling (NMDS) revealed a community gradient from sites dominated by Salmo trutta and Cottus species ( C. bairdi , C. beldingi ) to sites dominated by Catostomus platyrhynchus . Sites dominated by C. platyrhynchus were smaller in size and had less habitat cover, smaller average substrate size, higher concentrations of dissolved constituents, and higher water temperature than sites dominated by S. trutta . Sites dominated by C. platyrhynchus were located in more intensely urbanized watersheds at lower elevations. Stream size and associated instream habitat availability appear to limit S. trutta distribution and abundance, while native species appear more tolerant of decreased water quality and increased water temperatures in more urbanized streams. Most of the study sites are affected by development of water infrastructure for human water use (e.g., dams and diversions), and this infrastructure may play a role in dispersal of species.     

Distribution, abundance, and genetic population structure of Wood River sculpin, Cottus leiopomus

The Wood River sculpin Cottus leiopomus is endemic to the Wood River Basin in central Idaho and is a nongame species of concern because of its limited distribution. However, status and genetic population structure, 2 factors often central to the conservation and management of species of concern, have not been assessed for this species. We used backpack electrofishers to survey streams that were small enough (i.e., a priori to contain, possibly contain, or not contain the sculpin, respectively. Native redband trout Oncorhynchus mykiss gairdneri were present at 21 study sites, including 18 of the 20 sites that contained Wood River sculpin. Sixty-one study sites (60%) were dry or had too little water to contain any fish. We estimated that a minimum of 1.36 million Wood River sculpin (≥20 mm total length) currently reside in the basin. The presence of Wood River sculpin was positively associated with stream width:depth ratio and percent cobble/boulder substrate and negatively associated with stream gradient. Mitochondrial DNA haplotype differences were observed between and within the 3 major river subbasins supporting sculpin, with the most striking differences observed between populations in the Camas Creek subbasin and the other 2 subbasins, among which no haplotypes were shared, suggesting relatively long-term isolation. Our results suggest that the Wood River sculpin remains relatively widespread and abundant within its endemic range, despite obvious changes in historical stream connectivity caused by irrigation diversions and other chronic habitat alterations.     

Microhabitat use by the white‐clawed crayfish in a Tuscan stream

Habitat modification, pollution, overfishing, poaching, competition from non‐indigenous species, and diseases have led to the extinction in Europe of many populations of indigenous crayfish. Under the rationale that any programme of reintroduction should be preceded by a thorough understanding of habitat requirements of the species of concern, we studied the microhabitat use of an Austropotamobius pallipes population in Tuscany, central Italy. Microhabitat use was assessed for water depth, current velocity, substrate, percentages of boulders, underwater tree roots, and in‐stream vegetation cover. Results show that A. pallipes' habitat use is size‐partitioned. Smaller individuals mostly occupy stream edges in shallow waters with submerged roots, whereas larger individuals use deeper waters, often associated with boulders. Crayfish spatial distribution is restricted mostly to the microhabitats characterised by extensive cover and slow current velocity. The study highlights the importance of habitat heterogeneity and cover elements for the protection of this indigenous species.     

Food habits and dietary overlap of nongame insectivorous fishes in Flint Creek, Oklahoma, a western Ozark foothills stream

Insectivorous fishes were sampled from March, 1983 to February 1984, in Flint Creek, Delaware Co., Oklahoma. There was insignificant habitat segregation between Etheostoma spectabile and E. punctulatum and seasonal habitat partitioning between Cottus carolinae and both darters. Mature E. spectabile ate primarily chironomids and mayflies, whereas juveniles fed primarily on microcrustaceans. Mature E. punctulatum consumed fewer Ephemerella and Leptophlebia than E. spectabile , feeding on Stenonema and other crustaceans. Juvenile E. punctulatum fed mainly on amphipods and mayflies, and juvenile E. spectabile ate primarily microcrustaceans. Cottus carolinae elected primarily mayflies in spring - summer and chironomids in January - February. Coefficients of dietary overlap were highest between larger E. spectabile and juvenile E. punctulatum and lowest between immature E. spectabile and mature E. punctulatum . Overlap between the two darters was significantly correlated with differences in mean prey size (p E. spectabile was also significantly correlated to differences in mean prey sizes. Etheostoma spectabile generally preferred smaller prey than E. punctulatum . All three species avoided Stenelmis . Cottus carolinae avoided microcrustaceans. The study showed that resource partitioning among these three insectivorous fishes is affected by complex interactions of habitat and prey electivity, and prey size selectivity.         

Bird use of riparian vegetation along the Truckee River, Califonia and Nevada

The Truckee River in California and Nevada is subject to diverse water regimes and a corresponding variety of flow rates. Original riparian vegetation has been altered by these variable flow rates and by a variety of human uses resulting in loss of native riparian vegetation from its historic extent. We conducted bird surveys along the Truckee River during spring 193 to (1) determine relationships between birds and the present vegetation; (2) determine the importance of different vegetation types to sensitive bird species that have declined recently in the western United States due to competition from exotic plant species, cowbird ( Molothrus ater ) parasitism, reduction in nesting habitat, or other unidentified reasons; and (3) establish a monitoring program and collect baseline data for future comparisons. The most frequently detected bird species throughout the study was the Brown-headed Cowbird. The greatest number of bird species (98 of 116) was found in the native mixed willow ( Salix spp.) riparian scrub vegetation type. We recommend protecting the remaining native riparian vegetation types for bird habitat along the Truckee River.     

Breeding preferences in the treefrogs Dryophytes japonicus (Hylidae) in Mongolia

ABSTRACT

When a species occurs over a broad range of climates and landscapes, the breeding ecology of that species is expected to vary locally. Additionally, a basic knowledge of breeding ecology is required before other types of studies may be conducted, such as physiology or conservation. In North East Asia, Dryophytes japonicus is distributed from Japan to Mongolia, where its breeding ecology is unknown. The objectives of this study were to understand the breeding requirements of D. japonicus in this part of its range. We collected data for Dryophytes japonicus at 56 sites located within 23 independent localities in Northern Mongolia during the breeding season 2017. The data collected included habitat type and co-occurring amphibian, fishes and bird species. Our results show that the species prefers circa 70 m long oxbow lakes for breeding, while habitat characteristics, water quality and co-occurring species were not significantly associated with the occurrence of the species. We therefore conclude that D. japonicus is behaviourally plastic in Mongolia, as it is in other portions of its range, and that the species can use several types of environments and co-occur with different species at its breeding sites. Corvus dauuricus was the only bird species significant predicting the occurrence of D. japonicus, likely because of overlapping ecological preferences.     

Ecomorphology and habitat utilization of Echinocereus engelmannii and E. triglochidiatus (Cactaceae) in southeastern California

The relationship between form and habitat utilization of Echinocereus engelmannii and E. triglochidiatus was studied in southeastern California. The major difference in form is in the density of stems comprising the canopy. These differences in morphology create differences in the daily heat loads of each species. Echinocereus triglochidiatus, with its stems densely packed and in contact with each other over much of their lengths, continues to gain heat internally as the sun sets due to conductance between the stems. In contrast E. engelmannii, with a more open canopy, begins to lose heat as the sun goes down. As a result, E. triglochidiatus is successful in the juniper - pinyon zone where winter temperatures are cold for long periods and E. engelmannii is more successful in the lower desert regions where very hot, summer temperatures prevail. In the latter case, daytime buildup in heat load is reduced by convective cooling as air moves through the open canopy. Differences in microhabitat utilization occur that provide a second mechanism to reduce daily heat load buildup on hot summer days in the juniper - pinyon zone.     

Geographic patterns of ground-dwelling arthropods across an ecoregional transition in the North American Southwest

We examined the biogeographic patterns of ground-dwelling arthropod communities across a heterogeneous semiarid region of the Southern Rio Grande Rift Valley of New Mexico. Our 3 sites included portions of 5 ecoregions, with the middle site a transition area where all ecoregions converged. We addressed the following 3 questions: (1) Do the species assemblage patterns for ground arthropods across habitats and sites conform to recognized ecoregions? (2) Are arthropod assemblages in distinct vegetation-defined habitats within an ecoregion more similar to each other or to assemblages in similar vegetation-defined habitats in other ecoregions? (3) Is there a detectable edge effect with increased arthropod diversity in the area of converging ecoregions? We encountered 442 target arthropod species from pitfall traps operating continuously for 7 years over a series of different habitats at each of the 3 sites. We examined geographic distributions of spider and cricket/grasshopper species in detail, and they showed affinities for different ecoregions, respectively. Each habitat within a study site supported a unique overall arthropod assemblage; nevertheless, different habitats at the same site were more similar to each other than they were to similar habitats at other sites. Overall arthropod species richness was greatest in the area where all 5 ecoregions converged. Arthropod species and their geographic distributions are poorly known relative to vascular plants and vertebrate animals. Findings from this research indicate that ecoregional classification is a useful tool for understanding biogeographic patterns among arthropods.     

Habitat use by the South‐American rattlesnake (Crotalus durissus) in south‐eastern Brazil

Habitat use affects food intake, reproductive fitness and body temperature control in reptiles. Habitat use depends on both the characteristics of the animal and the environmental heterogeneity. In this study we investigated habitat use in a population of the South‐American rattlesnake, Crotalus durissus, in a cerrado (the Brazilian savanna) remnant, in south‐eastern Brazil. In general, snakes appeared to be thermal generalists. However, they showed substrate temperature preferences in the rainy season, when they selected colder substrates during the day and warmer substrates at night. Individuals were predominantly active on the surface and more frequently found under bushes. Furthermore, in general, the principal component analysis results indicate that rattlesnakes are generalists regarding the microhabitat variables examined in this study. These habitat characteristics, associated with a low thermal selectivity, indicate that rattlesnakes are able to colonize deforested areas where shade occurrence and vegetation cover are similar to those in the cerrado.     

Effects of habitat fragmentation and differing mobility on the population structures of a Great Basin dragonfly ( Sympetrum corruptum ) and damselfly ( Enallagma carunculatum )

The population structure of 2 Great Basin odonate species was assessed using protein electrophoresis. Analyses included 7 populations of Sympetrum corruptum (suborder Anisoptera), a migratory and highly mobile dragonfly, and 8 populations of Enallagma carunculatum (suborder Zygoptera), a weak flier that is not known to migrate far from natal water sources. Though we expected the damselfly ( E. carunculatum ) to show greater genetic isolation than the dragonfly ( S. corruptum ), both species apparently had high levels of gene flow (theta = 0.0604 for S. corruptum , theta = 0.0485 for E. carunculatum ) and showed no evidence for isolation by distance. These results suggest that both species are highly vagile and that the most important factors affecting population structure of these odonates may be ecological conditions such as habitat patchiness and the ephemerality of water sources.     

A new species of the genus Cytheridella (Crustacea,Ostracoda) from Nigeria,West Africa

Cytheridella tepida sp. nov., a freshwater ostracod, is described from Nigeria, West Africa. It has been compared with five extant species of the genus Cytheridella. Cytheridella tepida was collected from slow-flowing streams characterized by warm water. Some other ecological notes on its habitat are given.     

Associations of Small Mammals Occurring in a Pluvial Lake Basin, Ruby Lake, Nevada

Ruby Lake is a highly mesic and vegetationally diverse pluvial lake basin of east central Nevada. Small mammal associations were examined in six plant communities at Ruby Lake using transects of live traps. Small mammal activity was recorded for these six habitats plus an additional three other specialized habitats. A total of 11 species of small mammals were trapped from the six habitat types; from the entire study area 26 species were trapped or observed. Two greasewood shrub habitats and a shadscale-spiny hopsage habitat held the highest number of trapped species, 6, 5, and 7, respectively. The mesic haymeadow and spring habitats, as well as the big sagebrush-antelope bitterbrush habitat held 4 trapped species each. Peromyscus maniculatus and Perognathus parvus made up 76% of the total captures and were found in all habitat types except marshlands. Eutamius minimus was found in four of the six habitat types, while Dipodomys ordii , Dipodomys microps , Perognathus parvus , and Microtus montanus were limited to specialized habitats. Mesic adapted, wetland species such as Mustela vison , Ondatra zibethicus , and Sorex vagrans possibly dispersed into Ruby Valley from the northeastern drainages and valleys during the late Pleistocene or Holocene.     

Biogeography of coastal and anchialine amphipods of Ascension Island,South Atlantic Ocean

Over 8000 amphipods were examined from coastal (primarily intertidal) and anchialine pool habitats of Ascension Is. Twenty-seven species, of which 14 are undescribed, were identified. Comparison of species from Ascension with amphipods found in possible source areas suggests that most colonization of the island by these animals has been via the Benguela Current. Possible western Atlantic faunal contributions are significantly lower than for other marine taxa that have been studied at Ascension, all of which are generally characterized by having dispersive larval stages. The high proportion of apparently endemic species, which exceeds that described for amphipods of other oceanic islands, is probably due to both the island's isolation and incomplete faunal surveys in possible source areas. Amphipod species diversity is low, a probable consequence of the size, isolation, youth and low habitat variability of Ascension Is. Consistent with other Atlantic islands that have been studied, nestlers predominate (56% of the species), with tubicolous species (33%) of secondary importance and inquilines (11%) making only a minor contribution. Three species occur in the anchialine pool habitat. Rather unexpectedly, caprellid amphipods are absent.     

Large, wetland-associated mayflies (Ephemeroptera) of Glacier National Park, Montana

We describe species richness and habitat associations of mayflies (Ephemeroptera) collected during amphibian surveys of 355 water bodies in Glacier National Park (NP), Montana, in 2006–2008. We collected 9 taxa (in 7 genera) of mayflies that were identifiable to species. Callibaetis ferrugineus hageni was collected most frequently, followed by Siphlonurus occidentalis, S. phyllis, Ameletus celer, A. similior, Parameletus columbiae, Ephemerella dorothea infrequens, Baetis bicaudatus, and Leptophlebia cupida. Siphlonurus phyllis had not been reported in the western United States prior to our surveys, and P. columbiae is a species of concern in the region. The identifications of 4 additional taxa were uncertain due to the poor condition of specimens found at only one site ( Centroptilum sp. and Paraleptophlebia sp.) or because nymphal specimens could not be confidently identified ( Cinygma sp. and Cinygmula sp.). Species richness of mayflies in wetlands seems low compared to that in streams and lakes in Glacier National Park. We found the most species of mayflies in beaver ponds, where we detected some species not commonly associated with lentic water bodies. Our survey was the first extensive survey of wetland invertebrates in Glacier NP and only the second that we are aware of in western Montana.     

Marmot distribution and habitat associations in the Great Basin

In this study I describe the distribution and habitat associations of yellow-bellied marmots ( Marmota flaviventris ) in the Great Basin, compare my findings with those of E.R. Hall during his 1929-1936 survey and later surveys, and discuss potential reasons for changes in marmot distribution over time. I found 62 marmot burrow sites in 18 mountain ranges, mostly in rocky meadows situated on well-drained slopes between 2100 m and 3000 m elevation. Marmots were generally found near burrows dug within talus slopes, talus-like rock piles, or clusters of massive boulders. Oceanspray ( Holodiscus discolor ) was the shrub most commonly associated with occupied rock formations. Marmots were most abundant in the Ruby/East Humboldt Range and were common in the Desatoya, Shoshone, Toiyabe, Toquima, Cherry Creek, Schell Creek, Deep Creek, and Stansbury Ranges. Marmots appeared to be uncommon in the Monitor Range and rare in the Clan Alpine, Roberts, and Snake Ranges. I was unable to find marmots in the Diamond, Egan, Spruce-Pequop, White Pine, and Oquirrh Ranges, although I located old, weathered marmot scats in all but the latter 2 ranges. Other evidence confirms that marmots do actually occur in the Oquirrh Range, but extensive searches of the White Pine Range, including some of the same rock formations where E.R. Hall collected marmots, revealed no sign of marmots. My distribution data suggest that marmots may have gone extinct in some Great Basin mountain ranges during the last century. These disappearances may represent a natural extinction-recolonization dynamic, but a more alarming possibility is a recent die-off linked to climate change, which is predicted to force montane vegetation zones further upslope, shrinking the habitat of associated faunas. However, marmots in this study were observed as low as 1550 m elevation, indicating an altitudinal flexibility that may allow this species to survive climatic change better than more specialized boreal species such as pikas ( Ochotona princeps ) and water shrews ( Sorex palustris ).     

Habitat characteristics of leatherside chub ( Gila copei ) at two spatial scales

Populations of leatherside chub ( Gila copei ), a little-known species native to the eastern Great Basin, have declined and their distribution has become fragmented. To determine habitat requirements and possible factors responsible for population decline, we quantified macrohabitats and microhabitats occupied by leatherside chub. Macrohabitat was surveyed at 59 sites in the Sevier River drainage of south central Utah, and microhabitats occupied by leatherside chub were measured at 3 locations spanning the species latitudinal range. Characteristics of points in the stream where leatherside chub occurred were compared to points where they did not occur. Abundance of brown trout ( Salmo trutta ) and elevation were weakly negatively correlated with leatherside chub distribution on a macrohabitat scale. Microhabitats occupied by leatherside chub were characterized by low water velocities (2.5-45 cm sec -1 ), intermediate water depths (25-65 cm), and low percent composition of sand-silt or gravel substrates. This study suggests that the presence of introduced brown trout may have led to the decline of leatherside chub.     

Foraging mode of Australolacerta rupicola (FitzSimons, 1933) (Sauria: Lacertidae): evidence of seasonal variation in an extremely active predator?

Foraging mode of the endemic Soutpansberg rock lizard (Australolacerta rupicola) was determined by (1) measuring the number of movements per minute (MPM) and the percentage time spent moving (PTM); and (2) analysing faecal samples. Furthermore, these criteria were related to diet composition, proportion of attacks initiated while moving and foraging substrate. The results are discussed in comparison to the foraging modes of 20 other lacertid species. Values for MPM and PTM as well as faecal analysis indicate an active foraging strategy for A. rupicola. Although rock living, this species mostly forages in leaf litter where it is well camouflaged while actively searching for sedentary prey. Even in comparison to other active foragers of the family Lacertidae, A. rupicola displays the prototypic behaviour of a widely foraging lizard with very high PTM and very low MPM.