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Publications

Filter Total Items: 1990

Region-wide trends of nesting ospreys in northwestern Mexico: a three-decade perspective

We used a double-sampling technique (air plus ground survey) in 2006, with partial double coverage, to estimate the present size of the Osprey (Pandion haliaetus) nesting population in northwestern Mexico (coastal Baja California, islands in the Gulf of California, and coastal Sonora and Sinaloa). With the exception of Natividad, Cedros, and San Benitos islands along the Pacific coast of Baja Cali
Authors
Charles J. Henny, Daniel W. Anderson, Aradit Castellanos Vera, Jean-Luc E. Cartron

Environmental contaminants in male river otters from Oregon and Washington, USA, 1994-1999

This study reports hepatic concentrations and distribution patterns of select metals, organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in 180 male river otters (Lontra canadensis) collected from Oregon and Washington, 1994-1999. Seven regional locations of western Oregon and Washington were deline
Authors
R. A. Grove, C. J. Henny

Landscape-scale evaluation of genetic structure among barrier-isolated populations of coastal cutthroat trout, Oncorhynchus clarkii clarkii

Relationships among landscape structure, stochastic disturbance, and genetic diversity were assessed by examining interactions between watershed-scale environmental factors and genetic diversity of coastal cutthroat trout (Oncorhynchus clarkii clarkii) in 27 barrier-isolated watersheds from western Oregon, USA. Headwater populations of coastal cutthroat trout were genetically differentiated (mean
Authors
T.J. Guy, R. E. Gresswell, M. A. Banks

Four centuries of soil carbon and nitrogen change after stand-replacing fire in a forest landscape in the western Cascade Range of Oregon

Episodic stand-replacing wildfire is a significant disturbance in mesic and moist Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests of the Pacific Northwest. We studied 24 forest stands with known fire histories in the western Cascade Range in Oregon to evaluate long-term impacts of stand-replacing wildfire on carbon (C) and nitrogen (N) pools and dynamics within the forest floor (FF, Oe
Authors
T.W. Giesen, S.S. Perakis, K. Cromack

A double-observer method for reducing bias in faecal pellet surveys of forest ungulates

1. Faecal surveys are used widely to study variations in abundance and distribution of forest-dwelling mammals when direct enumeration is not feasible. The utility of faecal indices of abundance is limited, however, by observational bias and variation in faecal disappearance rates that obscure their relationship to population size. We developed methods to reduce variability in faecal surveys and i
Authors
K.J. Jenkins, B.F.J. Manly

Blood parasites in Owls with conservation implications for the Spotted Owl (Strix occidentalis)

The three subspecies of Spotted Owl (Northern, Strix occidentalis courina; California, S. o. occidentalis; and Mexican, S. o. lucida) are all threatened by habitat loss and range expansion of the Barred Owl (S. varia). An unaddressed threat is whether Barred Owls could be a source of novel strains of disease such as avian malaria (Plasmodium spp.) or other blood parasites potentially harmful for S
Authors
H.D. Ishak, J.P. Dumbacher, N.L. Anderson, J.J. Keane, G. Valkiunas, S. M. Haig, L.A. Tell, R.N.M. Sehgal

Movements of wintering Dunlin Calidris alpina and changing habitat availability in an agricultural wetland landscape

Few studies have assessed how the dynamics of wetland bird movements relate to changing resource availability, particularly at more than one spatial scale. Within western Oregon's Williamette Valley, we examined winter resident Dunlin Calidris alpina movements in relation to a decrease in availability of preferred shorebird foraging habitat from early to late winter of 1999-2000. By tracking movem
Authors
O.W. Taft, P.M. Sanzenbacher, S. M. Haig

Range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) in northwestern North America

The dynamic geological and climatic history of northwestern North America has made it a focal region for phylogeography. We conducted a range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) across its range in northwestern North America to understand its evolutionary history and the distribution of clades to inform conservation of R. pretiosa and Gre
Authors
W.C. Funk, C.A. Pearl, H.M. Draheim, M.J. Adams, T.D. Mullins, S. M. Haig

Western Juniper Field Guide: Asking the Right Questions to Select Appropriate Management Actions

Introduction Strong evidence indicates that western juniper has significantly expanded its range since the late 1800s by encroaching into landscapes once dominated by shrubs and herbaceous vegetation (fig. 1). Woodland expansion affects soil resources, plant community structure and composition, water, nutrient and fire cycles, forage production, wildlife habitat, and biodiversity. Goals of juni
Authors
R.F. Miller, J.D. Bates, T.J. Svejcar, F.B. Pierson, L.E. Eddleman

Landbird Monitoring Protocol for National Parks in the North Coast and Cascades Network

This protocol narrative outlines the rationale, sampling design and methods for monitoring landbirds in the North Coast and Cascades Network (NCCN) during the breeding season. The NCCN, one of 32 networks of parks in the National Park System, comprises seven national park units in the Pacific Northwest, including three large, mountainous, natural area parks (Mount Rainier [MORA] and Olympic [OLYM]
Authors
Rodney B. Siegel, Robert L. Wilkerson, Kurt J. Jenkins, Robert C. Kuntz, John R. Boetsch, James P. Schaberl, Patricia J. Happe

Science Review for the Scott Bar Salamander (Plethodon asupak) and the Siskiyou Mountains Salamander (P. stormi): Biology, Taxonomy, Habitat, and Detection Probabilities/Occupancy

The Plethodon elongatus Complex in the Klamath-Siskiyou Ecoregion of southern Oregon and northern California includes three species: the Del Norte salamander, Plethodon elongatus; the Siskiyou Mountains salamander, P. stormi; and the Scott Bar salamander, P. asupak. This review aims to summarize the current literature and information available on select topics for P. stormi and P. asupak. These ar
Authors
Douglas J. DeGross, R. Bruce Bury

Size of the California Brown Pelican Metapopulation During a Non-El Nino Year

Overall, we estimated a total metapopulation within the geographical range of the California brown pelican subspecies (Pelecanus occidentalis californicus) as about 70,680 ? 2,640 breeding pairs (mean ? SD). Little change in at least three decades is indicated in the total metapopulation south of the Southern California Bight (SCB) subpopulation, but significant improvements in the breeding subpop
Authors
Daniel W. Anderson, Charles J. Henny, Carlos Godinez-Reyes, Franklin Gress, Eduardo L. Palacios, Karina Santos del Prado, James Bredy