Book Chapters

No abstract available.

Competition for zooplankton between larval lake herring (Coregonus artedi) and lake whitefish (C. clupeaformis) was compared in mesocosm experiments in a small lake. Both species were combined in test enclosures at relative abundances of 1:1 or 1:4 lake herring to lake whitefish at densities of 500; 1, 000; and 2, 000 fish per cage, and were allowed to feed ad libitum on available zooplankton. Aft

The hypothesis that temperature was an epigamic factor in bloater (Coregonus hoyi) sex determination in Lake Michigan was tested by rearing bloater larvae in the laboratory at 6, 11, and 15 degrees C for the first 80 days after hatching. The percentages of females of fish exposed to the three treatment temperatures did not differ significantly from the expected, 50%. Therefore, the null hypothesis

The Westphalian C strata found in the northeastern part of the former Belgian coal district (Campine Basin), which is part of an extensive northwest European paralic coal basin, are considered. The thickness and lateral continuity of the Westphalian C coal seams vary considerably stratigraphically and areally. Sedimentological facies analysis of borehole cores indicates that the deposition of West

The inland edge of the Jurassic magmatic belt passes through the eastern Mojave Desert, where it was emplaced in ancient continental crust. Three intrusive units exposed there—the Ship and Clipper Mountains plutons and a dike swarm in the Old Woman and Piute Mountains and Kilbeck Hills—are broadly similar to each other and to other intrusions of Jurassic age, but they differ from one another in de

The size of the continental breeding population of northern pintail (Anas acuta) has greatly varied since 1955, with numbers in surveyed areas ranging from a high of 9.9 million to a low of 1.8 million in 1991. This variation results primarily from differences in the numbers of breeding pintails in the prairie region of Canada and the United States; these numbers ranged from 8.6 million in 1956 to

No abstract available.

An extensive review of geologic and tectonic features of western North America suggests that the interaction of oceanic plates with the continent follows a broad cyclical pattern. In a typical cycle, periods of rapid subduction (7–15 cm/yr), andesitic volcanism, and trench-normal contraction are followed by a shift to trench-normal extension, the onset of voluminous silicic volcanism, formation of

No abstract available.

The North American group of shorebirds includes 48 kinds of sandpipers, plovers, and their allies, many of which live for most of the year in coastal marine habitats; other live principally in nonmarine habitats including grasslands, freshwater wetlands, and even second-growth woodlands. Most North American shorebirds are highly migratory, while others are weakly migratory, and even nonmigratory i

Large changes have occurred in the geographic wintering distribution and subspecies composition of the Atlantic Flyway population of Canada geese (Branta canadensis) over the last 40 years. The Atlantic Flyway can be thought of as being partitioned into four regions: South, Chesapeake, mid-Atlantic, and New England. Wintering numbers have declined in the southern states (North Carolina, South Caro

Increased predation and habitat degradation and destruction coupled with drought, especially on breeding grounds, have caused the declines of some duck populations. More than 30 species of fucks breed in North America, in areas as diverse as the Arctic tundra and the subtropics of Florida and Mexico. For many of these species, however, the Prairie Pothole region of the north-central United States