California bighorn sheep (Ovis canadensis californiana) were studied on Hart Mountain, Oregon, during the summer and fall of 1976, and the spring of 1977. The population consisted of a minimum of 196 sheep in June, 1977. The high number of lambs observed and high lamb:ewe ratios throughout both years of...
From July 1985 to April 1987 the pelagic zooplankton community of Crater Lake, Oregon was studied to determine taxonomic structure, absolute and relative densities, and spatial and temporal distributional patterns. Samples were collected using vertically-towed zooplankton nets. The community structure consisted of two cladoceran and nine rotifer species, which were...
One of the biggest hurdles for a juvenile salmonid (Oncorhynchus mykiss) is migrating downstream from freshwater spawning grounds to the ocean. Juveniles from wild broodstock were reared from the South Santiam River for more than 1 year at the Oregon Hatchery Research Center (OHRC) in Alsea, OR. The fish were...
Millions of acres of rangeland in the western U.S. is shared habitat by elk (Cervus canadensis), mule deer (Odocoileus hemionus), and cattle (Bos taurus). Potential competition between these ungulates for the same forage species can be understood from their diet composition. I used DNA metabarcoding methods with trnL primers to...
Despite being a highly charismatic and frequently exhibited organism,
Giant Pacific Octopus (Enteroctopus dofleini) population dynamics
are poorly understood. Basic monitoring data for this species is
limited to bycatch and stomach contents of other fisheries species. An
essential step to a better estimation of population size and
productivity is to...
1. Early competitive environments can shape the development of offspring across taxa. For example, competition for food can have downstream effects on offspring phenotypes and fitness; however, little is known about how early competition influences the development of the hypothalamic-pituitary axis and its potential tradeoff with growth. Because baseline and...
Monitoring mercury (Hg) exposure in avian populations is critical to understanding the effects of this neurotoxin. Avian Hg exposure is commonly evaluated by measuring Hg concentrations in internal tissues, blood, and feathers. Feathers are a popular sampling matrix due to ease of sampling and limited stress to birds. However, it...
The Oregon chub (Oregonichthys crameri) is a small minnow (Family: Cyprinidae) endemic to Oregon’s Willamette Valley. In 1993, the Oregon chub was listed as endangered because of habitat loss and predation and competition by nonnative fishes. Conservation efforts by the Oregon Department of Fish and Wildlife (ODFW) and other agencies...
The newest pilot project at Tarangire National Park (TAR) is Income Generating Programs (IGP) where community groups organize themselves around an activity that earns income. TAR initiated the project by paying for ten members from each of the three existing community groups on the park’s northern end and fifteen members...