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This biogeographical study documents the modern distribution of ostracodes in the southwest Yukon Territory and northern British Columbia, Canada. The study tested the hypothesis that dissolved ion composition and concentrations of the lake water are the primary determinants of the distribution of modern ostracodes in this region. A total of 28 freshwater species representing 8 genera were identified in the 33 study lakes. Species common in the southwest Yukon are widely distributed throughout North America, and include Cyclocypris ampla , Candona candida , Cypria turneri , Cypria ophtalmica , and Candona protzi . Concentrations of ostracode valves were highest in four lakes with moderate conductivity values ranging...
Categories: Publication; Types: Citation; Tags: M1-Invertebrates
Testate amoebae are valuable indicators of peatland hydrology and have been used in many palaeoclimatic studies in peatlands. Because the species' ecological optima may vary around the globe, the development of transfer function models is an essential prerequisite for regional palaeoclimatic studies using testate amoebae. We investigated testate amoebae ecology in nine peatlands covering a 250-km north–south transect in south-central Alaska. Redundancy analysis and Mantel tests were used to establish the relationship between the measured environmental variables (water-table depth and pH) and testate amoebae communities. Transfer-function models were developed using weighted averaging, weighted average partial least...
Categories: Publication; Types: Citation; Tags: M1-Invertebrates
The distribution patterns of Orthoptera are described for the boreal zone. The boreal fauna of Eurasia includes more than 81 species. Many of them are widely distributed. The monotypic genus Paracyphoderris Storozhenko and at least 13 species are endemics or subendemics. About 50 species are known from boreal North America. Four endemic species are distributed very locally. Relationships between the faunas of the Eurasian and North American parts of the boreal zone are relatively weak. The boreal assemblages are usually characterized by the low levels of species diversity and abundance. Grasshoppers and their relatives occupy almost exclusively open habitats, such as different types of meadows, mountain steppes...
Categories: Publication; Types: Citation; Tags: M1-Invertebrates
Long-term monitoring of the rate of change of mountain pine beetle (Dendroctonus ponderosae Hopkins) populations requires detailed tree-level information over large areas. This information is used to assess the status of an infestation (e.g., increasing, stable, or decreasing), and to select and evaluate mitigation approaches. In this research project, the authors develop and demonstrate a prototype monitoring system, which enables the extrapolation of tree-level estimates of beetle damage from field data to a larger study area using a double sampling approach, and multi-scale, multi-source, high spatial resolution remotely sensed data. The project study area encompasses over 6 million ha and is located at the leading...
Categories: Publication; Types: Citation; Tags: M1-Invertebrates
Direct density-dependence through intraspecific competition may be an important mechanism permitting sustained herbivore outbreaks. In theory, interference competition could allow a relatively stable number of herbivore individuals to survive while moderating host plant damage. This research examined the potential role of intraspecific competition in permitting a decade-long outbreak of the aspen leaf miner, Phyllocnistis populiella, on Populus tremuloides in interior Alaska. A combination of observational and experimental studies examined larval food requirements, food resources, and the impacts of P. populiella larval density on survival, mass, and leaf mining damage. These results were then compared to those...
Categories: Publication; Types: Citation; Tags: M1-Invertebrates
ABSTRACT We compared macroinvertebrate assemblages sampled from artificial and natural substrates within a small, sandy-bottomed coastal plain stream, Alabama, USA. Separate samples were collected from natural coarse woody debris (CWD) accumulations, benthic sand substrate, and Hester-Dendy multiplate samplers (HDs, 54-d incubations). Shannon's H? was lowest and % dominant taxon was highest in sand samples. Proportion of the total assemblage as EPT taxa (Ephemeroptera, Plecoptera, and Trichcptera) was significantly higher on HDs than from sand, and proportion of the assemblage as Chironomidae was higher from sand than on CWD. Invertebrate biomass on HDs was almost two times higher than from sand, whereas biomass...
Categories: Publication; Types: Citation; Tags: M1-Invertebrates
Increased light reaching streams as a result of riparian vegetation management is often thought to be responsible for enhanced algal productivity. However, concomitant changes in nutrients and other physical processes confound that interpretation. We manipulated light in two separate experiments to test the role of light as a controlling factor for periphyton productivity and biomass, and to observe invertebrate responses in small streams in central British Columbia, Canada. We did this by adding artificial light to reaches of three forested streams, and in a second experiment we used shadecloth to cover reaches of two streams flowing through clearcuts. Periphyton growth, productivity and composition, and macroinvertebrate...
Categories: Publication; Types: Citation; Tags: M1-Ecosystems, M1-Invertebrates
Land snails have been investigated isotopically in tropical islands and mid-latitude continental settings, while high-latitude locales, where snails grow only during the summer, have been overlooked. This study presents the first isotopic baseline of live snails from Fairbanks, Alaska (64°51′N), a proxy calibration necessary prior to paleoenvironmental inferences using fossils. δ13C values of the shell (− 10.4 ± 0.4‰) and the body (− 25.5 ± 1.0‰) indicate that snails consumed fresh and decayed C3-plants and fungi. A flux-balance mixing model suggests that specimens differed in metabolic rates, which may complicate paleovegetation inferences. Shell δ18O values (− 10.8 ± 0.4‰) were ~ 4‰ higher than local summer rain...
Categories: Publication; Types: Citation; Tags: M1-Invertebrates


map background search result map search result map Monitoring and modeling terrestrial arthropod diversity on the Kenai National Wildlife Refuge Mountain Pine Beetle in British Columbia Monitoring and modeling terrestrial arthropod diversity on the Kenai National Wildlife Refuge Mountain Pine Beetle in British Columbia