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At least 973 records · Page 54Linked to original sources
USGS2012

Palynological composition of a Lower Cretaceous South American tropical sequence: Climatic implications and diversity comparisons with other latitudes.

Premise of the study : Reconstruction of floristic patterns during the early diversification of angiosperms is impeded by the scarce fossil record, especially in tropical latitudes. Here we collected quantitative palynological data from a stratigraphic sequence in tropical South America to provide floristic and climatic insights into such tropical environments during the Early Cretaceous. Methods : We reconstructed the floristic composition of an Aptian-Albian tropical sequence from central Colombia using quantitative palynology (rarefied species richness and abundance) and used it to infer its predominant climatic conditions. Additionally, we compared our results with available quantitative data from three other sequences encompassing 70 floristic assemblages to determine latitudinal diversity patterns. Key results : Abundance of humidity indicators was higher than that of aridity indicators (61% vs. 10%). Additionally, we found an angiosperm latitudinal diversity gradient (LDG) for the Aptian, but not for the Albian, and an inverted LDG of the overall diversity for the Albian. Angiosperm species turnover during the Albian, however, was higher in humid tropics. Conclusions : There were humid climates in northwestern South America during the Aptian-Albian interval contrary to the widespread aridity expected for the tropical belt. The Albian inverted overall LDG is produced by a faster increase in per-sample angiosperm and pteridophyte diversity in temperate latitudes. However, humid tropical sequences had higher rates of floristic turnover suggesting a higher degree of morphological variation than in temperate regions.

American Journal of Botany↗
USGS2017

Behavioral responses of Pacific lamprey to alarm cues

Pacific lamprey ( Entosphenus tridentatus ), an anadromous ectoparasite, faces several challenges during adult migration to spawning grounds. Developing methods to address these challenges is critical to the success of ongoing conservation efforts. The challenges are diverse, and include anthropogenic alterations to the ecosystem resulting in loss of habitat, impassable barriers such as dams, climate change impacts, and altered predator fields. We conducted a behavioral study to understand how adult migrating Pacific lamprey respond to potential alarm cues: White Sturgeon ( Acipenser transmontanus ), human saliva, decayed Pacific lamprey, and river otter ( Lontra canadensis ). Research has shown that some species of lamprey can be guided to a location using odors and similar cues may be useful as a management tool for Pacific lamprey. Experiments were conducted over 2 nights and measured the number of entries (count) and duration of time spent (occupancy) by adult lamprey in each arm of a two-choice maze. During the first night, no odor was added to test for selection bias between arms. During the second night odor was added to one arm of the maze. Contrary to expectations, lamprey were significantly attracted to the river otter odor in both count and occupancy. No significant differences were found in the response of lamprey to the other three odors. Results from this study indicate that Pacific lamprey do respond to some odors; however, additional tests are necessary to better identify the types of odors and concentrations that elicit a repeatable response.

Oregon, Washington↗
USGS2009

Distribution and abundance of host-seeking Culex species at three proximate locations with different levels of West Nile virus activity

Culex species were monitored at three proximate sites with historically different West Nile virus (WNV) activities. The site with human WNV transmission (epidemic) had the lowest abundance of the putative bridge vectors, Culex pipiens and Cx. salinarius . The site with horse cases but not human cases (epizootic) had the highest percent composition of Cx. salinarius , whereas the site with WNV-positive birds only (enzootic) had the highest Cx. pipiens abundance and percent composition. A total of 29 WNV-positive Culex pools were collected at the enzootic site, 17 at the epidemic site, and 14 at the epizootic site. Published models of human risk using Cx. pipiens and Cx. salinarius as the primary bridge vectors did not explain WNV activity at our sites. Other variables, such as additional vector species, environmental components, and socioeconomic factors, need to be examined to explain the observed patterns of WNV epidemic activity.

American Journal of Tropical Medicine and Hygiene↗
USGS2010

Prevalence and pathology of West Nile virus in naturally infected house sparrows, western Nebraska, 2008

Nestling birds are rarely sampled in the field for most arboviruses, yet they may be important in arbovirus amplification cycles. We sampled both nestling and adult house sparrows ( Passer domesticus ) in western Nebraska for West Nile virus (WNV) or WNV-specific antibodies throughout the summer of 2008 and describe pathology in naturally infected nestlings. Across the summer, 4% of nestling house sparrows were WNV-positive; for the month of August alone, 12.3% were positive. Two WNV-positive nestlings exhibited encephalitis, splenomegaly, hepatic necrosis, nephrosis, and myocarditis. One nestling sparrow had large mural thrombi in the atria and ventricle and immunohistochemical staining of WNV antigen in multiple organs including the wall of the aorta and pulmonary artery; cardiac insufficiency thus may have been a cause of death. Adult house sparrows showed an overall seroprevalence of 13.8% that did not change significantly across the summer months. The WNV-positive nestlings and the majority of seropositive adults were detected within separate spatial clusters. Nestling birds, especially those reared late in the summer when WNV activity is typically greatest, may be important in virus amplification.

Nebraska↗
USGS2013

Management, morphological, and environmental factors influencing Douglas-fir bark furrows in the Oregon Coast Range

Many land managers in the Pacific Northwest have the goal of increasing late-successional forest structures. Despite the documented importance of Douglas-fir tree bark structure in forested ecosystems, little is known about factors influencing bark development and how foresters can manage development. This study investigated the relative importance of tree size, growth, environmental factors, and thinning on Douglas-fir bark furrow characteristics in the Oregon Coast Range. Bark furrow depth, area, and bark roughness were measured for Douglas-fir trees in young heavily thinned and unthinned sites and compared to older reference sites. We tested models for relationships between bark furrow response and thinning, tree diameter, diameter growth, and environmental factors. Separately, we compared bark responses measured on trees used by bark-foraging birds with trees with no observed usage. Tree diameter and diameter growth were the most important variables in predicting bark characteristics in young trees. Measured environmental variables were not strongly related to bark characteristics. Bark furrow characteristics in old trees were influenced by tree diameter and surrounding tree densities. Young trees used by bark foragers did not have different bark characteristics than unused trees. Efforts to enhance Douglas-fir bark characteristics should emphasize retention of larger diameter trees' growth enhancement.

Oregon↗
USGS1985

Effects of pelletized anticoagulant rodenticides on California quail

A moribund, emaciated California quail (Callipepla californica) that was found in an orchard in the state of Washington had an impacted crop and gizzard. Pellets containing the anticoagulant chlorophacinone (Rozol, RO) were in the crop; the gizzard contents consisted of a pink mass of paraffin that was selectively accumulated from the paraffinized pellets. The plasma prothrombin time of 28 sec was near that determined for control quail. The signs of RO intoxication seen in the moribund wild quail were duplicated in captive quail given ad libitum diets of either RO or another paraffinized chlorophacinone pellet (Mr. Rat Guard II, MRG). This left little doubt that paraffin impaction of the gizzard was the primary problem. All captive quail fed RO or MRG pellets showed no increases in prothrombin times compared to control values, died in an emaciated condition, and had gizzards impacted with paraffin.

Journal of Wildlife Diseases↗
USGS1986

Avian tuberculosis and salmonellosis in a whooping crane (Grus americana)

The whooping crane has been the subject of intensive scientific study and management because it is an endangered species and has high public interest. Programs have been developed to identify critical habitat, to increase production through captive breeding, and in recent years, to use sandhill cranes (Grus canadensis) as surrogate parents in establishing new populations of wild whooping cranes. Only a few reports describing diseases and parasites in wild whooping cranes appear in the literature because opportunities to secure specimens are limited for this rare, protected bird (for review, see Carpenter and Derrickson, In Proc. International Crane Workshop of 1983, Bharatur, India, in press). Avian tuberculosis and concurrent salmonellosis in a wild whooping crane are described in this case report.

Colorado↗
USGS1988

Effects of the antimicrobic tiamulin on seven gram-negative bacterial fish pathogens

In vitro and in vivo tests were carried out with tiamulin and gram-negative bacterial pathogens of fish. Determination of minimum inhibitory concentration for 51 strains of seven species of gram-negative bacterial pathogens showed that only strains of Vibrio anguillarum were sensitive at 1.6–6.25 ppm, while the rest of test strains required 25– >100 ppm. Control of infection was not achieved when tiamulin was fed for 14 days at 5 or 50 mg/kg to rainbow trout ( Salmo gairdneri ) experimentally infected with Yersinia ruckeri .

Journal of Wildlife Diseases↗
USGS1988

A survey of the prevalence of selected bacteria in wild birds

We determined the prevalence of six genera of bacteria from a sample of 387 cloacal swabs from 364 passerines and woodpeckers. The prevalence of bacteria were as follows: Escherichia coli (1%), Pseudomonas spp. (22%), Salmonella spp. (0%), Staphylococcus spp. (15%), Streptococcus spp. (18%), and Yersinia spp. (1%). The prevalence of Streptococcus spp. was higher in omnivorous species than in granivorous species (20% versus 8%). Individuals captured at feeders had a lower prevalence of both Streptococcus spp. (15% versus 33%) and Escherichia coli (0.5% versus 4%) than birds that did not have access to feeders. These differences are probably not due to the feeder per se, but instead to other site related differences. The prevalence of bacteria did not differ between male and female black-capped chickadees, Parus atricapillus . For 279 color marked black-capped chickadees, we calculated the cumulative mortality rate during 12 wk following swabbing. Although the cumulative mortality rates of infected birds were consistently higher than the rates of non-infected birds, none of these differences were significant. Infections may cause slight reductions in survival rates, but we were not able to confirm this with our data.

Wisconsin↗
USGS1970

Chemotherapy of fish diseases: A review

Fish suffer from environmental, nutritional, viral, bacterial, parasitic, and neoplastic diseases, many of which are similar to those of higher animals. The prevention and treatment of these diseases follow the same principles as diseases of other animals. Fish culture is similar to poultry husbandry in that large numbers of animals are crowded into relatively small areas, feeding is free choice, and medication for systemic infections is usually oral. External treatment of fishes is more common than of poultry, due to a higher frequency of external diseases. Many of the drugs and chemicals used in chemotherapy of fishes are the same as for higher animals. The following is a brief review of the more important drugs and their methods of administration.

Journal of Wildlife Diseases↗
USGS1972

Some physiologic blood values of wild diving ducks

Blood samples were obtained from 54 canvasbacks ( Aythya valisineria ), 30 lesser scaup ( A. affinis ), 3 ring-necks ( A. collaris ), and 3 buffleheads ( Bucephala albeola ), which were wintering on Chesapeake Bay. These blood samples were used for: red blood cell counts (cans. 2.56 × 10 6 /mm 3 ; scaup 2.45 × 10 6 /mm 3 ; ring-necks 2.50 × 10 6 /mm 3 ; bufflehead 2.64 × 10 6 /mm 3 ), packed cell volume (cans. 52.2%; scaup 57.1%; ring-neck 49.1%; buffleheads 54.3%), total protein (cans. 4.4 g/100 ml; scaup 4.4 g/100 ml; ring-neck 3.5 g/100 ml; bufflehead 3.8 g/100 ml), erythrocyte measurements, and electrophoretic analysis of plasma and serum. Variations between individuals of the same species and sex were slight but a possible difference between male and female erythrocyte numbers and packed cell volumes was evident in the canvasback and scaup samples.

Maryland↗
USGS1972

Effect of certain anesthetic agents on mallard ducks

Four anesthetic agents used in human or veterinary medicine and 3 experimental anesthetic preparations were evaluated for effectiveness in inducing narcosis when administered orally to game-farm mallard ducks (Anas platyrhynchos).Tribromoethanol was the only compound to satisfy criteria of initial tests. Mean duration of the induction, immobilization, and recovery periods was 2.4 minutes, 8.7 minutes, and 1.3 hours, respectively, at the median effective dosage for immobilization (ED50; 100 mg./kg. of body weight). The median lethal dosage (LD50) was 400 mg./kg. of body weight.Tribromoethanol was also tested on mallards during the reproductive season. Effects on the hatchability of eggs or the survival of young were not detected.

Journal of the American Veterinary Medical Associa↗
USGS2000

Stratigraphy and historic accumulation of mercury in recent depositional sediments in the Sudbury River, Massachusetts, USA

The distribution and deposition of sedimentary mercury in the Sudbury River were linked to an industrial complex (Nyanza site) that operated from 1917 through 1978. In two reservoirs just downstream from the Nyanza site, estimated rates of mercury accumulation increased markedly in the 1920s and 1930s, were greatest during 1976-1982, decreased within 5 years after industrial operations ceased, and have decreased further since capping of contaminated soil at the Nyanza site was completed in 1991. The most contaminated sediments were typically buried, yet the 0- to 1-cm stratum remained substantially contaminated in all cores. Mercury accumulating in the surficial, reservoir sediments was probably from continuing, albeit much lesser, inputs from the Nyanza site, whereas recent inputs to downstream wetland areas were attributed to recycling of sedimentary mercury or to mercury from unidentified local sources. In the reservoirs, burial of highly contaminated sediments is gradually decreasing the amount of sedimentary mercury available for methylation. In downstream wetlands, however, sedimentary mercury seemed to be more available than that in the reservoirs for physical transport and biogeochemical cycling.

Canadian Journal of Fisheries and Aquatic Sciences↗