A new mechanistic approach for the further development of a population with established size bimodality
Lisa Heerman, Donald L. DeAngelis, Jost Borcherding
2017, PLoS ONE (12) 1-18
Usually, the origin of a within-cohort bimodal size distribution is assumed to be caused by initial size differences or by one discrete period of accelerated growth for one part of the population. The aim of this study was to determine if more continuous pathways exist allowing shifts from the small...
Length limits fail to restructure a Largemouth Bass population: A 28‐year case history
Leandro E. Miranda, M.E. Colvin, A. C. Shamaskin, L. A. Bull, T. Holman, R. Jones
2017, North American Journal of Fisheries Management (37) 624-632
Length limits have been implemented by fisheries management agencies to achieve population density, size structure, and angler satisfaction objectives. By redirecting harvest towards or away from particular length‐ or age‐groups, length limits rely on harvest by anglers to maintain a population at or near a desired state. The fish population...
Forecasted range shifts of arid-land fishes in response to climate change
James E. Whitney, Joanna B. Whittier, Craig P. Paukert, Julian D. Olden, Angela L. Strecker
2017, Reviews in Fish Biology and Fisheries (27) 463-479
Climate change is poised to alter the distributional limits, center, and size of many species. Traits may influence different aspects of range shifts, with trophic generality facilitating shifts at the leading edge, and greater thermal tolerance limiting contractions at the trailing edge. The generality of relationships between traits and range...
Quantile regression of microgeographic variation in population characteristics of an invasive vertebrate predator
Shane R. Siers, Julie A. Savidge, Robert Reed
2017, PLoS ONE (12) 1-19
Localized ecological conditions have the potential to induce variation in population characteristics such as size distributions and body conditions. The ability to generalize the influence of ecological characteristics on such population traits may be particularly meaningful when those traits influence prospects for successful management interventions. To characterize variability in invasive...
The morphology of transverse aeolian ridges on Mars
Paul Geissler, Justin T. Wilgus
2017, Aeolian Research (26) 63-71
A preliminary survey of publicly released high resolution digital terrain models (DTMs) produced by the High Resolution Imaging Science Experiment (HiRISE) camera on Mars Reconnaissance Orbiter identified transverse aeolian ridges (TARs) in 154 DTMs in latitudes from 50°S to 40°N. Consistent with previous surveys, the TARs identified in HiRISE DTMs...
Uncertainties in forecasting the response of polar bears to global climate change
David C. Douglas, Todd C. Atwood
Andy Butterworth, editor(s)
2017, Book chapter, Marine animal welfare
Several sources of uncertainty affect how precisely the future status of polar bears (Ursus maritimus) can be forecasted. Foremost are unknowns about the future levels of global greenhouse gas emissions, which could range from an unabated increase to an aggressively mitigated reduction. Uncertainties also arise because different climate...
Reflected stochastic differential equation models for constrained animal movement
Ephraim M. Hanks, Devin S. Johnson, Mevin Hooten
2017, Journal of Agricultural, Biological, and Environmental Statistics (22) 353-372
Movement for many animal species is constrained in space by barriers such as rivers, shorelines, or impassable cliffs. We develop an approach for modeling animal movement constrained in space by considering a class of constrained stochastic processes, reflected stochastic differential equations. Our approach generalizes existing methods for modeling unconstrained animal...
Erosion characteristics and horizontal variability for small erosion depths in the Sacramento-San Joaquin River Delta, California, USA
David H. Schoellhamer, Andrew J. Manning, Paul A. Work
2017, Ocean Dynamics (67) 799-811
Erodibility of cohesive sediment in the Sacramento-San Joaquin River Delta (Delta) was investigated with an erosion microcosm. Erosion depths in the Delta and in the microcosm were estimated to be about one floc diameter over a range of shear stresses and times comparable to half of a typical tidal cycle....
A multistate dynamic site occupancy model for spatially aggregated sessile communities
Keiichi Fukaya, J. Andrew Royle, Takehiro Okuda, Masahiro Nakaoka, Takashi Noda
2017, Methods in Ecology and Evolution (8) 757-767
Estimation of transition probabilities of sessile communities seems easy in principle but may still be difficult in practice because resampling error (i.e. a failure to resample exactly the same location at fixed points) may cause significant estimation bias. Previous studies have developed novel analytical methods to correct...
Is motivation important to brook trout passage through culverts?
Elsa Goerig, Theodore R. Castro-Santos
2017, Canadian Journal of Fisheries and Aquatic Sciences (74) 885-893
Culverts can restrict movement of stream-dwelling fish. Motivation to enter and ascend these structures is an essential precursor for successful passage. However, motivation is challenging to quantify. Here, we use attempt rate to assess motivation of 447 brook trout (Salvelinus fontinalis) entering three culverts under a range of hydraulic, environmental,...
Sediment source fingerprinting as an aid to catchment management: A review of the current state of knowledge and a methodological decision-tree for end-users
A.L Collins, S. Pulley, I.D.L Foster, Allen C. Gellis, P. Porto, A.J. Horowitz
2017, Journal of Environmental Management (194) 86-108
The growing awareness of the environmental significance of fine-grained sediment fluxes through catchment systems continues to underscore the need for reliable information on the principal sources of this material. Source estimates are difficult to obtain using traditional monitoring techniques, but sediment source fingerprinting or tracing procedures, have emerged as a...
Harvest and group effects on pup survival in a cooperative breeder
David E. Ausband, Michael S. Mitchell, Carisa R. Stansbury, Jennifer L. Stenglein, Lisette P. Waits
2017, Proceedings of the Royal Society B: Biological Sciences (284)
Recruitment in cooperative breeders can be negatively affected by changes in group size and composition. The majority of cooperative breeding studies have not evaluated human harvest; therefore, the effects of recurring annual harvest and group characteristics on survival of young are poorly understood. We evaluated how harvest and groups affect...
Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits
Amrita Bhattacharyya, Kate M. Campbell, Shelly Kelly, Yvonne Roebbert, Stefan Weyer, Rizlan Bernier-Latmani, Thomas Borch
2017, Nature Communications (8)
Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit...
A decade of boreal rich fen greenhouse gas fluxes in response to natural and experimental water table variability
David Olefeldt, Eugénie S. Euskirchen, Jennifer W. Harden, Evan S. Kane, A. David McGuire, Mark P. Waldrop, Merritt R. Turetsky
2017, Global Change Biology (23) 2428-2440
Rich fens are common boreal ecosystems with distinct hydrology, biogeochemistry and ecology that influence their carbon (C) balance. We present growing season soil chamber methane emission (FCH4), ecosystem respiration (ER), net ecosystem exchange (NEE) and gross primary production (GPP) fluxes from a 9-years water table manipulation experiment in an Alaskan...
Aerodynamic roughness length estimation with lidar and imaging spectroscopy in a shrub-dominated dryland
Aihua Li, Wenguang Zhao, Jessica J Mitchell, Nancy F. Glenn, Matthew J. Germino, Joel B. Sankey, Richard M. Allen
2017, Photogrammetric Engineering and Remote Sensing (83) 415-427
The aerodynamic roughness length (Z0 m) serves an important role in the flux exchange between the land surface and atmosphere. In this study, airborne lidar (ALS), terrestrial lidar (TLS), and imaging spectroscopy data were integrated to develop and test two approaches to estimate Z0 m over a shrub dominated dryland study area in...
Amphibians, pesticides, and the amphibian chytrid fungus in restored wetlands in agricultural landscapes
Rebecca A. Reeves, Clay Pierce, Mark W. Vandever, Erin L. Muths, Kelly L. Smalling
2017, Herpetological Conservation and Biology (12) 68-77
Information on interactions between pesticide exposure and disease prevalence in amphibian populations is limited, especially from field data. Exposure to certain herbicides and insecticides has the potential to decrease the immune response in frogs, which can potentially lead to increased abundance of Batrachochytrium dendrobatidis (Bd) zoospores on individuals and in...
Benchmarking computational fluid dynamics models of lava flow simulation for hazard assessment, forecasting, and risk management
Hannah R. Dietterich, Einat Lev, Jiangzhi Chen, Jacob A. Richardson, Katharine V. Cashman
2017, Journal of Applied Volcanology (6)
Numerical simulations of lava flow emplacement are valuable for assessing lava flow hazards, forecasting active flows, designing flow mitigation measures, interpreting past eruptions, and understanding the controls on lava flow behavior. Existing lava flow models vary in simplifying assumptions, physics, dimensionality, and the degree to which they have been validated...
Projecting community changes in hazard exposure to support long-term risk reduction: A case study of tsunami hazards in the U.S. Pacific Northwest
Benjamin M. Sleeter, Nathan J. Wood, Christopher E. Soulard, Tamara Wilson
2017, International Journal of Disaster Risk Reduction (22) 10-22
Tsunamis have the potential to cause considerable damage to communities along the U.S. Pacific Northwest coastline. As coastal communities expand over time, the potential societal impact of tsunami inundation changes. To understand how community exposure to tsunami hazards may change in coming decades, we projected future development (i.e. urban, residential,...
Calculation of in situ acoustic sediment attenuation using off-the-shelf horizontal ADCPs in low concentration settings
Dan Haught, Jeremy G. Venditti, Scott Wright
2017, Water Resources Research (53) 5017-5037
The use of “off-the-shelf” acoustic Doppler velocity profilers (ADCPs) to estimate suspended sediment concentration and grain-size in rivers requires robust methods to estimate sound attenuation by suspended sediment. Theoretical estimates of sediment attenuation require a priori knowledge of the concentration and grain-size distribution (GSD), making the method impractical to apply...
Assessment of frequency and duration of point counts when surveying for golden eagle presence
Ben R. Skipper, Clint W. Boal, Jo-Szu Tsai, Mark R. Fuller
2017, Wildlife Society Bulletin (41) 212-223
We assessed the utility of the recommended golden eagle (Aquila chrysaetos) survey methodology in the U.S. Fish and Wildlife Service 2013 Eagle Conservation Plan Guidance. We conducted 800-m radius, 1-hr point-count surveys broken into 20-min segments, during 2 sampling periods in 3 areas within the Intermountain West of the United...
Analyzing cloud base at local and regional scales to understand tropical montane cloud forest vulnerability to climate change
Ashley E. Van Beusekom, Grizelle Gonzalez, Martha A. Scholl
2017, Atmospheric Chemistry and Physics (17) 7245-7259
The degree to which cloud immersion provides water in addition to rainfall, suppresses transpiration, and sustains tropical montane cloud forests (TMCFs) during rainless periods is not well understood. Climate and land use changes represent a threat to these forests if cloud base altitude rises as a result of regional warming...
Enclosed nests may provide greater thermal than nest predation benefits compared with open nests across latitudes
Thomas E. Martin, Andy J. Boyce, Karolina Fierro-Calderon, Adam E. Mitchell, Connor E. Armstad, James C. Mouton, Evertius E. Bin Soudi
2017, Functional Ecology (31) 1231-1240
Nest structure is thought to provide benefits that have fitness consequences for several taxa. Traditionally, reduced nest predation has been considered the primary benefit underlying evolution of nest structure, whereas thermal benefits have been considered a secondary or even non-existent factor. Yet, the relative roles of these...
Effects of temperature, total dissolved solids, and total suspended solids on survival and development rate of larval Arkansas River Shiner
Julia S. Mueller, Timothy B. Grabowski, Shannon K. Brewer, Thomas A. Worthington
2017, Journal of Fish and Wildlife Management (8) 79-88
Decreases in the abundance and diversity of stream fishes in the North American Great Plains have been attributed to habitat fragmentation, altered hydrological and temperature regimes, and elevated levels of total dissolved solids and total suspended solids. Pelagic-broadcast spawning cyprinids, such as the Arkansas River Shiner Notropis girardi, may be particularly vulnerable...
Reexamining ultrafiltration and solute transport in groundwater
Christopher E. Neuzil, Mark Person
2017, Water Resources Research (53) 4922-4941
Geologic ultrafiltration—slowing of solutes with respect to flowing groundwater—poses a conundrum: it is consistently observed experimentally in clay-rich lithologies, but has been difficult to identify in subsurface data. Resolving this could be important for clarifying clay and shale transport properties at large scales as well as interpreting solute and isotope...
The greenscape shapes surfing of resource waves in a large migratory herbivore
Ellen O. Aikens, Matthew J. Kauffman, Jerod Merkle, Samantha Dwinnell, Gary L. Fralick, Kevin L. Monteith
2017, Ecology Letters (20) 741-750
The Green Wave Hypothesis posits that herbivore migration manifests in response to waves of spring green-up (i.e. green-wave surfing). Nonetheless, empirical support for the Green Wave Hypothesis is mixed, and a framework for understanding variation in surfing is lacking. In a population of migratory mule deer (Odocoileus hemionus), 31% surfed...
