Life Sciences Commons^™

Temporal And Spatial Influences On Fawn Summer Survival In Pronghorn Populations: Management Implications From Noninvasive Monitoring, Cole A. Bleke, Eric M. Gese, Juan J. Villalba, Shane B. Roberts, Susannah S. French

Wildland Resources Student Research

Monitoring vital rates allows managers to estimate trends in growth rates of ungulate populations. However, connecting the influence of nutrition on ungulate demography is challenging. Noninvasive sampling offers a low-cost, low-effort alternative for measuring nutritional indices, allowing for an increased understanding of the mechanistic relationships between environmental factors, nutrition, and specific population vital rates. We examined the temporal influence of intrinsic and extrinsic factors on pronghorn (Antilocapra americana) fawn recruitment. We collected fresh fecal samples from adult female pronghorn in five subpopulations spanning three sampling periods associated with critical maternal life-history stages (late gestation, early lactation, breeding season) …

Are Plant–Soil Feedbacks Caused By Many Weak Microbial Interactions?, Julia K. Aaronson, Andrew Kulmatiski, Leslie E. Forero, Josephine Grenzer, Jeanette M. Norton

Wildland Resources Student Research

We used high-throughput sequencing and multivariate analyses to describe soil microbial community composition in two four-year field plant–soil feedback (PSF) experiments in Minnesota, USA and Jena, Germany. In descending order of variation explained, microbial community composition differed between the two study sites, among years, between bulk and rhizosphere soils, and among rhizosphere soils cultivated by different plant species. To try to identify soil organisms or communities that may cause PSF, we correlated plant growth responses with the microbial community composition associated with different plants. We found that plant biomass was correlated with values on two multivariate axes. These multivariate axes …

Moderate Plant–Soil Feedbacks Have Small Effects On The Biodiversity–Productivity Relationship: A Field Experiment, Josephine Grenzer, Andrew Kulmatiski, Leslie Forero, Anne Ebeling, Nico Eisenhauer, Jeanette Norton

Wildland Resources Student Research

Plant–soil feedback (PSF) has gained attention as a mechanism promoting plant growth and coexistence. However, most PSF research has measured monoculture growth in greenhouse conditions. Translating PSFs into effects on plant growth in field communities remains an important frontier for PSF research. Using a 4-year, factorial field experiment in Jena, Germany, we measured the growth of nine grassland species on soils conditioned by each of the target species (i.e., 72 PSFs). Plant community models were parameterized with or without these PSF effects, and model predictions were compared to plant biomass production in diversity–productivity experiments. Plants created soils that changed subsequent …

Plant-Soil Feedbacks Help Explain Biodiversity-Productivity Relationships, Leslie E. Forero, Andrew Kulmatiski, Josephine Grenzer, Jeanette M. Norton

Wildland Resources Student Research

Species-rich plant communities can produce twice as much aboveground biomass as monocultures, but the mechanisms remain unresolved. We tested whether plant-soil feedbacks (PSFs) can help explain these biodiversity-productivity relationships. Using a 16-species, factorial field experiment we found that plants created soils that changed subsequent plant growth by 27% and that this effect increased over time. When incorporated into simulation models, these PSFs improved predictions of plant community growth and explained 14% of overyielding. Here we show quantitative, field-based evidence that diversity maintains productivity by suppressing plant disease. Though this effect alone was modest, it helps constrain the role of factors, …

Space Use And Relative Habitat Selection For Immature Green Turtles Within A Caribbean Marine Protected Area, Lucas P. Griffin, Brian J. Smith, Michael S. Cherkiss, Andrew G. Crowder, Clayton G. Pollock, Zandy Hillis-Starr, Andy J. Danylchuk, Kristen M. Hart

Wildland Resources Student Research

Background

A better understanding of sea turtle spatial ecology is critical for the continued conservation of imperiled sea turtles and their habitats. For resource managers to develop the most effective conservation strategies, it is especially important to examine how turtles use and select for habitats within their developmental foraging grounds. Here, we examine the space use and relative habitat selection of immature green turtles (Chelonia mydas) using acoustic telemetry within the marine protected area, Buck Island Reef National Monument (BIRNM), St. Croix, United States Virgin Islands.

Results

Space use by turtles was concentrated on the southern side of …

Western Bumble Bee: Declines In The Continental United States And Range-Wide Information Gaps, Tabitha A. Graves, William M. Janousek, Sarah M. Gaulke, Amy C. Nicholas, Douglas A. Keinath, Christine M. Bell, Syd Cannings, Richard G. Hatfield, Jennifer M. Heron, Jonathan B. Koch, Helen L. Loffland, Leif L. Richardson, Ashley T. Rohde, Jessica Rykken, James P. Strange, Et Al.

Wildland Resources Student Research

In recent decades, many bumble bee species have declined due to changes in habitat, climate, and pressures from pathogens, pesticides, and introduced species. The western bumble bee (Bombus occidentalis), once common throughout western North America, is a species of concern and will be considered for listing by the U.S. Fish and Wildlife Service (USFWS) under the Endangered Species Act (ESA). We attempt to improve alignment of data collection and research with USFWS needs to consider redundancy, resiliency, and representation in the upcoming species status assessment. We reviewed existing data and literature on B. occidentalis, highlighting information gaps …

The Importance Of The Northeastern Gulf Of Mexico To Foraging Loggerhead Sea Turtles, Kristen M. Hart, Margaret M. Lamont, Autumn R. Iverson, Brian J. Smith

Wildland Resources Student Research

Identification of high-use foraging sites where imperiled sea turtles are resident remains a globally-recognized conservation priority. In the biodiverse Gulf of Mexico (GoM), recent telemetry studies highlighted post-nesting foraging sites for federally threatened loggerhead turtles (Caretta caretta). Our aim here was to discern loggerhead use of additional northern GoM regions that may serve as high-use foraging sites. Thus, we used satellite tracking and switching state-space modeling to show that the Big Bend region off the northwest Florida coast is a coastal foraging area that supports imperiled adult female loggerhead turtles tracked from different nesting subpopulations. From 2011 to …

Calf And Yearling Prices In California And The Western United States, Tina Saitone, Larry C. Forero, Glenn A. Nader, Leslie A. Forero

Wildland Resources Student Research

This paper investigates spatial, quality and temporal factors impacting the pricing of calves and yearlings in the western United States using data from a satellite video auction and a hedonic regression framework. Results suggest that spatial price discounts received by western ranchers closely match reported shipping costs and, thus, are consistent with free-on-board pricing and competitive procurement. This study also identifies the presence of temporal price premiums, on average, for seller-offered forward contracts at video auctions. With respect to quality attributes, this study provides estimates of the marginal value associated with various quality attributes and management practices, including vaccination protocols, …