997 resultados para Isle Royale (Mich.)
Resumo:
Landscape structure and heterogeneity play a potentially important, but little understood role in predator-prey interactions and behaviourally-mediated habitat selection. For example, habitat complexity may either reduce or enhance the efficiency of a predator's efforts to search, track, capture, kill and consume prey. For prey, structural heterogeneity may affect predator detection, avoidance and defense, escape tactics, and the ability to exploit refuges. This study, investigates whether and how vegetation and topographic structure influence the spatial patterns and distribution of moose (Alces alces) mortality due to predation and malnutrition at the local and landscape levels on Isle Royale National Park. 230 locations where wolves (Canis lupus) killed moose during the winters between 2002 and 2010, and 182 moose starvation death sites for the period 1996-2010, were selected from the extensive Isle Royale Wolf-Moose Project carcass database. A variety of LiDAR-derived metrics were generated and used in an algorithm model (Random Forest) to identify, characterize, and classify three-dimensional variables significant to each of the mortality classes. Furthermore, spatial models to predict and assess the likelihood at the landscape scale of moose mortality were developed. This research found that the patterns of moose mortality by predation and malnutrition across the landscape are non-random, have a high degree of spatial variability, and that both mechanisms operate in contexts of comparable physiographic and vegetation structure. Wolf winter hunting locations on Isle Royale are more likely to be a result of its prey habitat selection, although they seem to prioritize the overall areas with higher moose density in the winter. Furthermore, the findings suggest that the distribution of moose mortality by predation is habitat-specific to moose, and not to wolves. In addition, moose sex, age, and health condition also affect mortality site selection, as revealed by subtle differences between sites in vegetation heights, vegetation density, and topography. Vegetation density in particular appears to differentiate mortality locations for distinct classes of moose. The results also emphasize the significance of fine-scale landscape and habitat features when addressing predator-prey interactions. These finer scale findings would be easily missed if analyses were limited to the broader landscape scale alone.
Resumo:
attached letter: Dear Professor Lorch: At the suggestion of the July 31, 1953 Newsletter of the Michigan Historical Society I am sending you two photoes [sic] of the old lighthouse and adjoining building on Presque Isle, Michigan located on the shore of Huron lake, supposedly the oldest lighthouse on the Great Lakes. It is owned by Mr. F. B. Stebbins, 326 N. Capital, Lansing, Michigan. When through using the photos I would appreciate your returning them directly to him. The following information was given to me by Mr. Stebbins: Built in 1840, through a congressional appropriation of $5,000.- in Presque Isle county, described as, "Where a portage of 200 yards would save 4 miles of canoe trip." Jefferson Davis after graduation from West Point, was supposed to have built it. (According to careful historical investigation, this is not true. There is an article about this controversy in some back number of the Michigan History magazine. Mr. Stebbins feels very strongly about his. He prefers the legend, it sounds bigger). Francis Burgoyne Stebbins purchased from his Uncle Bliss Stebbins in 1930, who bought the property in 1930 from General Duffield of Dteoirt [sic], who had purchased it from the government a short time previously. This light-house was abandone [sic] upon the completion of a new lighthouse in 1872, one mile north from the present location. Adjoining house was used as a summer home. Condition restored in 1936. Lighthouse towe [sic] walls 3 feet thick with handhewn circular stone steps to the top. Signed, Lee H. Gregory
Resumo:
verso: (where papa and mama both taught and first met)
Resumo:
The northern biotype of Echinococcus granulosus occurs throughout the holarctic zones of tundra and taiga, from eastern Fennoscandia to the Bering Strait in Eurasia and in North America from arctic Alaska approximately to the northern border of the United States. The cycle of the cestode is complex in taiga at lower latitudes, because of the greater diversity of potential hosts. In the Arctic and Subarctic, however, four patterns of predator/prey relationships may be discerned. Two natural cycles involve the wolf and wild reindeer and the wolf and elk (moose), respectively. Where deer of the two species coexist, both are prey of the wolf; the interactions of the wolf and elk are here described on the basis of long-term observations made on Isle Royale (in Lake Superior near the southern limit of taiga), where only the wolf and elk serve as hosts for E. granulosus. A synanthropic cycle involving herding-dogs and domesticated reindeer caused hyperendemicity of cystic echinococcosis in arctic Eurasia, mainly in northeastern Siberia. The 4th pattern, a semi-synanthropic cycle, formerly existed in Alaska, wherein sled-dogs of the indigenous hunters became infected by consuming the lungs of wild reindeer. The sequence of changes in life-style inherent in the process of acculturation affected the occurrence of cystic echinococcosis among nomadic Iñupiat in arctic Alaska. When those people became sedentary, the environs of their early villages soon became severely contaminated by feces of dogs, and cases of cystic echinococcosis occurred. Compared to cystic echinococcosis caused by E. granulosus adapted to synanthropic hosts (dog and domestic ungulates), the infection produced by the northern biotype is relatively benign. 0fearly all diagnosed cases of cystic echinococcosis (> 300 in Alaska have occurred in indigenous people; only one fatality has been recorded (in a non-indigenous person). After sled-dogs were replaced by machines, cases have become rare in Alaska. A similar effect has been observed in Fennoscandia, in the Saami and domesticated reindeer. Recent records indicate tbat the prcvalence of cystic echinococcosis is increasing in Russia, suggesting that dogs are used there in herding.