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Potential effects of anthropogenic greenhouse gases on avian habitats and populations in the northern Great Plains

Biotic response to the buildup of greenhouse gases in Earth's atmosphere is considerably more complex than an adjustment to changing temperature and precipitation. The fertilization effect carbon dioxide has on some plants, the impact UVB radiation has on health and productivity of organisms, and the resulting changes in competitive balance and trophic structure must also be considered. The intent of this paper is to review direct and indirect effects of anthropogenic greenhouse gases on wildlife, and to explore possible effects on populations of birds and their habitats in the northern Great Plains.Many of the potential effects of increasing greenhouse gases, such as declining plant nutritional value, changes in timing of insect emergence, and fewer and saltier wetlands, foreshadow a decline in avian populations on the Great Plains. However, other possible effects such as increased drought resistance and water use efficiency of vegetation, longer growing seasons, and greater overall plant biomass promise at least some mitigation. Effects of multiple simultaneous perturbations such as can be expected under doubled carbon dioxide scenarios will require substantial basic research to clarify.

American Midland Naturalist

Characteristics of mineral licks used by white-tailed deer (Odocoileus virginianus)

Characteristics of mineral licks used by white-tailed deer ( Odocoileus virginianus ) were examined in the northern Black Hills of South Dakota in May 1992. Concentrations of sodium, nitrogen, phosphorus, potassium, calcium, chloride and magnesium, and soil texture, organic matter and pH for licks and nonlick soils were compared. Black Hills lick and nonlick samples also were compared to 67 other North American licks characterized by Jones and Hanson (1985). Degree of use (high or low), and vegetative and topographic characteristics also were determined. Use of mineral licks by deer was highest in spring and early summer; mineral licks were not used by deer in winter. Mostly adult females, and on a few occasions fawns visited licks. Soil texture was finer and organic matter was lower (P < 0.05) in lick than nonlick soils. Soil pH, soluble salts, sodium and nitrate nitrogen were higher (P < 0.05) in lick than in nonlick soils. Chloride was the only mineral that differed (P = 0.03) between high-use and low-use licks but was not considered important in lick selection. Sodium was the primary mineral sought by white-tailed deer using mineral licks.

American Midland Naturalist

Minnesota wolf dispersal to Wisconsin and Michigan

Records are presented of three wolves that dispersed ≥200 km from northern Minnesota to the Minnesota-Wisconsin border, to southern Wisconsin, and to Michigan. This report documents that wolves cross major highways and other developed areas and that the recently recolonized wolf population in Wisconsin and Michigan could have originated from wolf populations in Minnesota other than those living along the Minnesota-Wisconsin border.

Michigan, Minnesota, Wisconsin

Distribution of Yellowstone grizzly bears during the 1980s

Grizzly bear ( Ursus arctos horribilis ) females with young occupied a greater proportion of area east of Yellowstone National Park during 1980-1989 compared to 1973-1979. Occupancy by all bears and females with young was lower in all peripheral areas compared to the Park, but greater east and south compared to north and south of the Park. Observed changes reflect not only a static or slightly increasing population trend, but may also reflect biases in data collection. These biases are discussed and distributions of all observations and females with young are presented. Methodological problems implicit in analyzing changes in distribution of grizzly bears are also discussed.

Idaho, Montana, Wyoming

Wolf nipple measurements as indices of age and breeding status

We measured nipple sizes of 29 captive wolves ( Canis lupus ), of known breeding histories, throughout the year and tested distinctions among various known breeding statuses of 20 wild wolves examined in northeastern Minnesota from May through September. For ca. 8 mo of the year only breeders and nonbreeders can be classified. Distinctions between current and former breeders were not reliable.

American Midland Naturalist

A single deer stands-off three wolves

The first record of a deer ( Odocoileus virginianus ) standing off three wolves ( Canis lupus ) is documented by an aerial observation in northeastern Minnesota.

American Midland Naturalist