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Habitat Use by Brood-Rearing Waterfowl in Subarctic Québec
, 1995
"... ABSTRACT. Aerial surveys of waterfowl were conducted in subarctic Québec in 1989 and 1990 on randomly selected 100 km2 plots. We used logistic regression for modelling relationships between the presence of waterfowl broods and habitat characteristics. For each species, models of habitat use were gen ..."
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ABSTRACT. Aerial surveys of waterfowl were conducted in subarctic Québec in 1989 and 1990 on randomly selected 100 km2 plots. We used logistic regression for modelling relationships between the presence of waterfowl broods and habitat characteristics. For each species, models of habitat use were generated with one data set and tested with two others. We also compared the frequency distributions of broods of each species in different habitat types. Correct-classification rates of models varied between 0.53 and 0.77. Sensitivity of models generally increased when applied to validation data sets. Models showed that green-winged teals (Anas crecca) avoided lakes> 501 ha and used vegetated lakes, ponds and fens or bogs more than predicted by their availability. Black scoters (Melanitta nigra) and surf scoters (M. perspicillata) were found mostly on small lakes (< 10 ha) and medium lakes (10 –100 ha). Black scoters were associated with the presence of ponds and lakes with sedge and grass, whereas surf scoters were not. The presence of scaup (Aythia spp.) broods was associated with the presence of vegetation. Green-winged teals were observed more often on bogs than were either scoters or scaups. Black scoters were observed more often on ponds and less often on medium-sized lakes than surf scoters and scaups. The latter differed in their use of lakes < 10 ha: surf scoters, like black scoters, mostly used unvegetated lakes, while scaups and green-winged teals mostly used vegetated lakes. The accuracy and precision of logistic models may be enhanced by additional habitat variables, careful selection of sample-cell size and further investigation of the breeding biology of the surveyed species. Key words: habitat, model, logistic regression, northern Québec, black scoter, surf scoter, green-winged teal, scaup, brood
Title: Ecology of Mallard Ducklings on Lower Klamath National Wildlife Refuge, California Abstract approved: Redacted for Privacy
, 1991
"... The ecology of female mallards (Abas platyrhynchos) and their broods was studied during 1988-90 on Lower Klamath National Wildlife Refuge, California. Survival of 127 radio-marked ducklings from 64 broods was 0.18 to 10 days of life, and 0.37 and 0.34 to fledging for 1988, 1989, and 1990, respective ..."
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The ecology of female mallards (Abas platyrhynchos) and their broods was studied during 1988-90 on Lower Klamath National Wildlife Refuge, California. Survival of 127 radio-marked ducklings from 64 broods was 0.18 to 10 days of life, and 0.37 and 0.34 to fledging for 1988, 1989, and 1990, respectively. For the 3 years of the study, 49.2 % of hens lost their entire brood; 81.2, 36.8, and 37.5 % in 1988, 1989, and 1990, respectively. Ninety-three percent of mortality occurred on or before 10 days of life. No significant differences were detected in the proportion of radio-marked ducklings lost from early hatched or late hatched nests. A variety of predators consumed radio-marked ducklings; however, 49 % of the cases of mortality were a result of an unknown predator. During 1989 and 1990, 3 radio-marked ducklings from 16 hens which appeared to lose their entire brood were fledged by other brood hens, and of 29 radio-marked ducklings that reached 44 days of life, 6 (20.7%) had joined other broods.
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"... “The prairie, in all its expressions, is a massive, subtle place, with a long history of contradiction and misunderstanding. But it is worth the effort at comprehension. It is, after all, at the center of our national identity.” William Least Heat Moon (1991) Grasslands rank among the most biologica ..."
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“The prairie, in all its expressions, is a massive, subtle place, with a long history of contradiction and misunderstanding. But it is worth the effort at comprehension. It is, after all, at the center of our national identity.” William Least Heat Moon (1991) Grasslands rank among the most biologically productive of all communities (Williams and Diebel 1996). Their high productivity stems from high retention of nutrients, efficient biological recycling, and a structure that provides for a vast array of animal and plant life (Estes et al. 1982). Grasses have contributed the hereditary material for the principal human food crops—rice, wheat, corn, and other grains. Worldwide production of such grain crops exceeds all other food crops combined. Grasslands also contribute immense value to watersheds and provide forage and habitat for large numbers of domestic and wild animals. Nevertheless, current levels of erosion in North America exceed the prairie soil’s capacity to tolerate sediment and nutrient loss, thus threatening a resource essential
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International Affairs and Commodity Programs.
, 2007
"... The stage is set for a land fight in the 2007 Farm Bill. Analysts at the World Bank point out that farmers need to double food output over the next 50 years to meet the needs of 9 billion people. High energy prices and government programs are encouraging the conversion of agricultural commodities ..."
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The stage is set for a land fight in the 2007 Farm Bill. Analysts at the World Bank point out that farmers need to double food output over the next 50 years to meet the needs of 9 billion people. High energy prices and government programs are encouraging the conversion of agricultural commodities to fuel. Urban and rural sprawl is eating away millions of productive farmland acres annually. The struggle for land between food and fuel will ultimately be won by food, but the damage to wildlife and the environment could be enormous if governments around the world do not embrace resource protection measures and productivity enhancements. In the United States, 36 million acres of farmland have been rented from farmers by the USDA Conservation Reserve Program (CRP) to control surplus production and protect the environment. These acres are now being viewed as a source of land to relieve the pressure from food and fuel demands.1 Environmental and wildlife advocates are caught in the middle.
Canada, the Natural Sciences and
, 2015
"... spatial prediction, waterfowl management. ..."
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