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At least 829 records · Page 46Linked to original sources
USGS1995

Paleogeography and the Late Cretaceous of the Western Interior of middle North America; coal distribution and sediment accumulation

A synthesis of Late Cretaceous paleogeography of the Western Interior from Mexico to southwestern Canada emphasizes the areal distribution of peat-forming environments during six biostratigraphically constrained time intervals. Isopach maps of strata for each interval reveal the locations and magnitude of major depocenters. The paleogeographic framework provides insight into the relative importance of tectonism, eustasy, and climate on the accumulation of thick peats and their preservation as coals. A total of 123 basin summaries and their data provide the ground truth for construction of the isopach and paleogeographic maps.

Professional Paper↗
USGS1993

Genetic comparison of viral hemorrhagic septicemia virus isolates from North America and Europe

Viral hemorrhagic septicemia virus (VHSV) is the cdusative agent of a serious rhabdoviral d~sease of rainbow trout Oncorhynchus myklss in Europe The first isolation of the vlrus in North Amenca occurred In the fall of 1988 when it was recovered from adult chinook 0 tshawytscha and coho 0 klsutch salmon returning to 2 hatcher~es in the state of Washington, USA The following year, VHSV was isolated from adult coho salmon at 2 other hatcher~es in northwestern Washington In 1990 and 1991, VHSV was recovered from Pacific cod Gadus macrocephalus caught in Pnnce Willlam Sound, Alaska Genetic vanation among the 4 isolates from salmon and the 1990 ~solate from Pacific cod was determ~ned uslng T1 nbonuclease finqerprlnt~ng In addition, 4 d~verse isolates from Europe were lncluded for companson The North Amencan isolates of VHSV formed a slngle fingerprint group In which the 4 isolates from salmonids were h~ghly similar to each other and the isolate from Pacific cod was related but less s~milar The 4 European ~solates which included an isolate from Atlantic cod G morhua, formed a second fingerpnnt group The genetic d~vers~ty among the isolates within each fingerpnnt group was estimated to be less than 5 % whlle the North Amencan and European strains of the virus were judged to differ by more than 5% The results indicate that the North Amerlcan isolates of VHSV are not of European ongln and that the virus may be enzootic wlthin the manne environment.

Diseases of Aquatic Organisms↗
USGS2018

Spatial and temporal patterns in population trends and burrow usage of burrowing owls in North America

Many researchers have suggested that abundance of Burrowing Owls ( Athene cunicularia ) has declined in many portions of their breeding range, but a thorough review of their population trends over time is lacking. Published population trends from the North American Breeding Bird Survey program suggested that Burrowing Owl populations in the US have declined over the past 60 yr, but the declines were not considered significant until 2014. However, accurate trend estimates and the statistical significance of those estimates were hampered by low relative abundance of owls. Moreover, many authors have suggested that eradication of burrowing animals is a major cause of Burrowing Owl declines, because burrows dug by burrowing animals are a critical resource for Western Burrowing Owls ( A. cunicularia hypugaea ). Despite this, we currently lack a range-wide summary of the burrowing animals on which Western Burrowing Owls depend. To help fill these two information gaps, my objectives were to: (1) use Breeding Bird Survey (BBS) data to examine geographic patterns in population trends of Burrowing Owls throughout their breeding range in the USA, and (2) use past studies to provide the first summary of the spatial extent to which Western Burrowing Owls rely on the suite of burrowing animals throughout their breeding range. Significantly more BBS routes in the US show declining counts of owls than show increasing or stable counts, and the declines were most apparent prior to 1995. Counts of Burrowing Owls declined most precipitously on the northern edge and southern edge of the owl's US breeding range. Western Burrowing Owls primarily use black-tailed prairie dog ( Cynomys ludovicianus ) burrows in the eastern portion of their breeding range, whereas the diversity of burrowing species on which the owls depend is much greater in the western and central portions of their breeding range. Burrowing owl declines have been most apparent in portions of their range where they rely primarily on Richardson's ground squirrels ( Urocitellus richardsonii ), California ground squirrels ( Otospermophilus beecheyi ), black-tailed prairie dogs, and American badgers ( Taxidea taxus ).

Journal of Raptor Research↗