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Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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In order to determine the impact of lesser snow goose (Chen caerulescens caerulescens) herbivory on above and belowground nutrient dynamics, a grazing and nutrient addition experiment was conducted in two habitat types utilized by snow geese near Churchill, Manitoba. Forage plant nutrition, soil microbial biomass, and inorganic and organic soil nutrients were measured in relation to the timing of grazing, over two consecutive summers. Soil was collected from the rhizosphere to determine the influence of foliar herbivory on root-microbe interactions. Primary productivity in both habitats is co-limited by the availability of both nitrogen (N) and phosphorus (P). Aboveground defoliation either caused a reduction or no change in soil microbial biomass nutrients (carbon (C), N, or P). Defoliated shoots had higher N concentrations and did not show compensatory growth within the season. Root biomass was somewhat reduced with grazing, but higher whole plant N content suggests that grazing does not compromise N-uptake.

In order to determine the impact of lesser snow goose (Chen caerulescens caerulescens) herbivory on above and belowground nutrient dynamics, a grazing and nutrient addition experiment was conducted in two habitat types utilized by snow geese near Churchill, Manitoba. Forage plant nutrition, soil microbial biomass, and inorganic and organic soil nutrients were measured in relation to the timing of grazing, over two consecutive summers. Soil was collected from the rhizosphere to determine the influence of foliar herbivory on root-microbe interactions. Primary productivity in both habitats is co-limited by the availability of both nitrogen (N) and phosphorus (P). Aboveground defoliation either caused a reduction or no change in soil microbial biomass nutrients (carbon (C), N, or P). Defoliated shoots had higher N concentrations and did not show compensatory growth within the season. Root biomass was somewhat reduced with grazing, but higher whole plant N content suggests that grazing does not compromise N-uptake.

The reproductive efficiency in the grandparent stock and the parent stock of geese was monitored in the thesis. In terms of the grandparent stock, there were found out better values in year 2012 than in year 2013. In 2012, there was a better egg fertilization of 4.61 % (the average was 49.65 %) and hatchability of the put eggs better of 3.83 % (the average was 39.01 %). The hatchability of the fertilized eggs was almost the same in both years. It has the same value of 78.63 %. Best results were proved in strains 1, 3 and 4. Worst values were proved in the strain number 41. The chosen indicators of geese of four ponds were monitored in the parent stock. The average fertilization of eggs was 58.26%; significantly higher value was proved in case of the Jakulský pond (72.34%). The average hatchability of the put eggs reached 46.46%; the highest value was also proved on the Jakulský pond (56.22%). The other ponds have balanced results. The hatchability of the fertilized eggs reached the average value of 79.10%, the highest value was proved on the Lomský pond (84.45%); the second place is represented by the Velebil pond (79.42%). The geese bred on the Lomský pond had eggs with the lowest fertilization, but with the highest percent of hatchability of the fertilized eggs. In case of geese bred on the Velebil pond, there was an increase of the monitored indicators in year 2013 than in 2012. In contrast, the Byňovský pond, the Jakulský pond and the Lomský pond showed an increase of the monitored indicators in 2012. There was a smaller difference of egg fertilization in geese of the Jakulský and the Lomský pond. There was a smaller difference of hatchability indicators of either put or fertilized eggs in geese bred on the Byňovský and the Jakulský pond.

A twenty-one year (1952-72) accumulation of banding data for Canada geese in Utah was studied to determine the distribution and chronology of the harvest of the geese and the effects that hunting regulations have had upon harvests and population parameters. The banding data were also used in an attempt to develop a population model capable of predicting population trends and desirable survival rates. Within Utah, the bulk of the annual harvest (78 percent) takes place in the northern portion of the State in the vicinity of the Great Salt Lake marshes. In Northern Utah the harvest peaks on the opening weekend, and approximately 50 percent of the annual harvest takes place by day 21 of an average hunting season of 82 days. Most of the harvest in Northern Utah is made up of geese produced in Utah. Peak harvests in Southern Utah do not occur until well into the average season, and non- Utah produced geese comprise a larger proportion of the harvest in Southern Utah than in Northern Utah. The harvest in Eastern Utah appears to be largely dependent on geese produced outside of the State. Outside Utah, harvests of Utah produced Canada geese have increased. Prior to 1950, over 80 percent of the recoveries of Utah-banded geese were made in Utah. The percentage steadily declined to less than 50 during the early 1970s. Stepwise multiple regression analysis revealed that only one hunting regulation, the daily bag limit, had a statistically significant relationship with estimates of annual harvests and band recovery rates . No regulations had statistically significant relationships with estimates of annual survival rates. Annual estimates of band recovery rates declined significantly during the period 1952-72, but estimates of annual survival rates for the same period showed no significant trend and were comparable to pre-1950 estimates. The attempt to formulate a population model was a failure. This was due in part to calculation errors associated with critical input to the model. However, the failure was largely due to the lack of a theoretically sound foundation.

The occurrence and ecology of the apicomplexan parasite Toxoplasma gondii in arctic wildlife is not well understood. Transmission cycles, especially in terrestrial systems, are enigmatic because environmentally resistant oocysts, shed by felid definitive hosts, might be less responsible for transmission in the Arctic than in more southern latitudes. Toxoplasma gondii can also be transmitted through the food web by carnivory, and by transmission from mother to fetus during gestation, and these routes are thought to play a large role in the ecology of T. gondii in the Arctic. In this thesis, I examine T. gondii in a well-described part of the food web at Karrak Lake, Nunavut, in the central Canadian Arctic and through experimental infections of domestic waterfowl. In the field over 3 years, I sampled generalist carnovires (arctic foxes), migratory herbivores (Ross’s Geese and Lesser Snow Geese), and resident herbivores (lemmings). Using an occupancy modeling approach that accounted for imperfect detection, I compared commonly used serological assays to estimate prevalence of T. gondii antibodies in sera from arctic foxes and eluted blood on filter paper from Ross’s geese and Lesser Snow Geese and compared commonly used serological assays. I also used a naïve estimator to determine prevalence of T. gondii antibodies in sera from Ross’s Geese and Lesser Snow Geese, and blood on filter paper from lemmings. I detected antibodies against T. gondii in sera from arctic foxes (47-60%, depending on age category), Ross’s Geese (32%) and Lesser Snow Geese (28%). I also detected antibodies in blood on filter paper from Ross’s Geese (39% seropositive) and Lesser Snow Geese (36% seropositive) but not in lemmings. These findings suggest that light geese might introduce T. gondii to the Karrak Lake ecosystem with the annual spring migration and that oocyst transmission might not occur in the terrestrial system, because the parasite was not detected in resident rodents. For the in vivo experimental infections, we used a novel application of a multi-scale occupancy framework to determine within-host detection probability of T. gondii in experimentally inoculated domestic geese and then used those results to guide tissue sampling in wild Ross’s Geese and Lesser Snow Geese. In the experimental inoculation trial, the heart and brain had the highest detection probability for T. gondii through a real-time PCR with melt-curve analysis. Toxoplasma gondii DNA was not detected in tissues from wild geese, suggesting that the parasite was either not present, or methodological difficulties prevented its detection. The research presented in this thesis forms the groundwork for further T. gondii studies in this region.