Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 7 of 7

Full-Text Articles in Life Sciences

Intraspecific Variation In Prey Susceptibility Mediates The Consumptive Effect Of Predation: A Case Study Of Yellowstone Elk And Wolves, Lacy M. Smith Dec 2021

Intraspecific Variation In Prey Susceptibility Mediates The Consumptive Effect Of Predation: A Case Study Of Yellowstone Elk And Wolves, Lacy M. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The reintroduction of wolves (Canis lupus) to Yellowstone National Park starting in 1995 is an important case study for understanding the consequences of predation on a prey population. Simulation studies conducted prior to and shortly after wolf reintroduction predicted that wolf predation of elk (Cervus canadensis) would have a modest influence on elk abundance. Predation of elk by wolves has been well documented and elk have remained the primary prey for wolves despite a decline in elk abundance. I used two quantitative approaches to estimate the influence of wolf predation on adult female elk survival and …


Range-Wide Declines Of Northern Spotted Owl Populations In The Pacific Northwest: A Meta-Analysis, Alan B. Franklin, Katie M. Dugger, Damon B. Lesmeister, Raymond J. Davis, J. David Wiens, Gary C. White, James D. Nichols, James E. Hines, Charles B. Yackulic, Carl J. Schwarz, Steven H. Ackers, L. Steven Andrews, Larissa L. Bailey, Robin Bown, Jesse Burgher, Kenneth P. Burnham, Peter C. Carlson, Tara Chestnut, Mary M. Conner, Krista E. Dilione, Eric D. Forsman, Elizabeth M. Glenn, Scott A. Gremel, Keith A. Hamm, Dale R. Herter, J. Mark Higley, Rob B. Horn, Julianna M. Jenkins, William L. Kendall, David W. Lamphear, Christopher Mccafferty, Trent L. Mcdonald, Janice A. Reid, Jeremy T. Rockweit, David C. Simon, Stan G. Sovern, James K. Swingle, Heather Wise Jul 2021

Range-Wide Declines Of Northern Spotted Owl Populations In The Pacific Northwest: A Meta-Analysis, Alan B. Franklin, Katie M. Dugger, Damon B. Lesmeister, Raymond J. Davis, J. David Wiens, Gary C. White, James D. Nichols, James E. Hines, Charles B. Yackulic, Carl J. Schwarz, Steven H. Ackers, L. Steven Andrews, Larissa L. Bailey, Robin Bown, Jesse Burgher, Kenneth P. Burnham, Peter C. Carlson, Tara Chestnut, Mary M. Conner, Krista E. Dilione, Eric D. Forsman, Elizabeth M. Glenn, Scott A. Gremel, Keith A. Hamm, Dale R. Herter, J. Mark Higley, Rob B. Horn, Julianna M. Jenkins, William L. Kendall, David W. Lamphear, Christopher Mccafferty, Trent L. Mcdonald, Janice A. Reid, Jeremy T. Rockweit, David C. Simon, Stan G. Sovern, James K. Swingle, Heather Wise

USDA Wildlife Services: Staff Publications

The northern spotted owl (Strix occidentalis caurina) inhabits older coniferous forests in the Pacific Northwest and has been at the center of forest management issues in this region. The immediate threats to this federally listed species include habitat loss and competition with barred owls (Strix varia), which invaded from eastern North America. We conducted a prospective meta-analysis to assess population trends and factors affecting those trends in northern spotted owls using 26 years of survey and capture-recapture data from 11 study areas across the owls' geographic range to analyze demographic traits, rates of population change, and occupancy parameters for spotted …


Compatibility Of Entomopathogenic Nematodes With Plant Extracts And Post-Exposure Virulence Test Under Laboratory Condition, Adeola Abiola Oso, Tshimangadzo Ramakuwela, Anofi Omotayo Tom Ashafa Jan 2021

Compatibility Of Entomopathogenic Nematodes With Plant Extracts And Post-Exposure Virulence Test Under Laboratory Condition, Adeola Abiola Oso, Tshimangadzo Ramakuwela, Anofi Omotayo Tom Ashafa

Turkish Journal of Zoology

The efficacy of both botanical pesticides and entomopathogenic nematodes (EPN) is largely dose-dependent and driven by environmental conditions. Combination of the EPNs and botanicals may enhance their efficacy; thus, we investigated the compatibility of the medicinal plants Alepidea amatymbica and Elephantorrhiza elephantina with five locally isolated EPN strains, three Steinernema (S. khoisanae, S. biddulphi and S. innovationi) and two Heterorhabditis (H. bacteriophora and Heterorhabditis sp. SGI 244). The experiments were designed to evaluate EPNs survival in plant extracts extracted using water and ethanol at 1%, 0.75%, 0.50%, 0.25% and 0.125% concentrations and nematode viability post-exposure. A concentration of 1000 IJs/mL …


Factors Influencing Survival Rates Of Pronghorn Fawns In Idaho, Brett R. Panting, Eric M. Gese, Mary M. Conner, Scott Bergen Jan 2021

Factors Influencing Survival Rates Of Pronghorn Fawns In Idaho, Brett R. Panting, Eric M. Gese, Mary M. Conner, Scott Bergen

USDA Wildlife Services: Staff Publications

Pronghorn (Antilocapra americana) occur throughout western North America. In Idaho, USA, following intensive hunting to reduce crop depredations in the late 1980s, pronghorn populations have not rebounded to desired levels. Because neonatal survival in ungulates is one factor limiting population growth, we evaluated cause‐specific mortality and the influence of intrinsic and extrinsic factors on survival rates of 217 radio‐collared pronghorn fawns across 3 study areas in Idaho during 2015–2016. For intrinsic variables, we determined the sex and body mass index (BMI) for each fawn. For extrinsic variables, we determined the abundance of predators and alternate prey, estimated the …


Space Use In Free-Ranging Canids: Are Gonadal Hormones Required For Territory Maintenance?, Eric M. Gese, Patricia A. Terletzky Jan 2021

Space Use In Free-Ranging Canids: Are Gonadal Hormones Required For Territory Maintenance?, Eric M. Gese, Patricia A. Terletzky

USDA Wildlife Services: Staff Publications

Fertility control among carnivores has been used to reduce depredations on livestock and wild neonates, population control, modify behavior, inhibit genetic introgression, and reduce human–wildlife conflicts. Although there is considerable knowledge on techniques to sterilize carnivores, there is little information concerning how the absence of gonadal hormones influences behavior, space use, and survival of wild canids. We examined territorial fidelity, home-range size and overlap, and survival of 179 surgically sterilized free-ranging canids (124 coyotes (Canis latrans Say, 1823), 55 coyote – red wolf (Canis rufus Audubon and Bachman, 1851) hybrids) with gonadal hormones present (tubal-ligated females (n = 70), vasectomized …


A Reintroduction Retrospective: Comparative Fisher (Pekania Pennanti) Survival And Prey Habitat Use In The Cascade Mountains Of Washington State, Tanner S.T. Humphries Jan 2021

A Reintroduction Retrospective: Comparative Fisher (Pekania Pennanti) Survival And Prey Habitat Use In The Cascade Mountains Of Washington State, Tanner S.T. Humphries

Graduate Student Theses, Dissertations, & Professional Papers

Increasing human impacts on biodiversity highlight the global need for ecological restoration. For many wildlife species, reintroduction is necessary to re-establish populations in parts of their historic range where they have been extirpated. Reintroduction efforts are commonly used to help restore ecosystem integrity, but are often expensive, time consuming, and unsuccessful at generating self-sustaining populations. Thus, a more complete understanding of the factors affecting restoration success is important for ensuring successful outcomes and responsible stewardship. Fishers (Pekania pennanti) are one of the most commonly reintroduced carnivores in North America, but the success of such efforts is highly variable, …


Effects Of Large Wood Restoration On Coho Salmon In A Northern California Watershed: A Before-After-Control-Impact Experiment, Natalie B. Okun Jan 2021

Effects Of Large Wood Restoration On Coho Salmon In A Northern California Watershed: A Before-After-Control-Impact Experiment, Natalie B. Okun

Cal Poly Humboldt theses and projects

Substantial time, money, and effort are invested in river and stream restoration projects to aid in the recovery of imperiled salmonid populations, but there is little evidence that these efforts have had lasting positive impacts on juvenile fish growth and survival. To assess the effectiveness of large woody debris (LWD) restoration, which is one of the most common restoration practices, I evaluated the growth and survival response of endangered Central California Coast coho salmon (Oncorhynchus kisutch) in a paired watershed before-after impact-control (BACI) study. To determine if LWD supplementation influenced coho salmon growth and survival, two neighboring, similar …