Life Sciences Commons^™

Consequences Of Recruitmentdecisions And Heterogeneity On Age-Specific Breeding Success In A Long-Lived Seabird, Lise M. Aubry, David N. Koons, Jean Yves Monnat, Emmanuelle Cam

Wildland Resources Faculty Publications

An individual’s age at first reproduction and investment in successive reproductive attempts are involved in mechanisms that can impede somatic repair, resulting in a decline in reproductive abilities with age (reproductive senescence). We used long-term data from the Black-legged Kittiwake, a long-lived seabird, to address the relationship between recruitment age, age-specific breeding success (BS), and reproductive senescence, while accounting for breeding experience and temporal variation in BS. We first detected late-life improvement in BS across all recruitment groups, which we recognized as ‘‘within-generation selection’’ or the selective disappearance of ‘‘frail’’ phenotypes. When such heterogeneity was accurately accounted for, we showed …

Energy Budgets Of Eared Grebes On The Great Salt Lake And Implications For Harvest Of Brine Shrimp, Michael R. Conover, Joe N. Caudell

Wildland Resources Faculty Publications

About 1.5-million eared grebes (Podiceps nigricollis), representing half of the North American population, stage on Utah's Great Salt Lake, USA (GSL) during autumn migration to forage on brine shrimp (Artemia franciscana). Indirectly competing with birds for brine shrimp are commercial harvesters who annually collect >1 million kg (dry wt) of shrimp cysts (i.e., hardened eggs), an amount that during some years equals up to half of all brine shrimp cysts produced annually on the GSL. No information was available regarding what impact this commercial harvest was having on eared grebes. We determined daily energy requirements of eared grebes so that …

Concentrations Of Selenium And Mercury In Eared Grebes (Podiceps Nigricollis) From Utah’S Great Salt Lake, Usa, Michael R. Conover, Josh L. Vest

Wildland Resources Faculty Publications

We examined selenium and mercury concentrations in eared grebes (Podiceps nigricollis) that spent the fall of 2006 on the Great Salt Lake (UT, USA), where their diet consisted mainly of brine shrimp (Artemia franciscana). Selenium concentrations in livers varied based on when the grebes were collected (lower in September [mean ± standard error, 9.4 ± 0.7 μg/g dry wt] than in November [14.5 ± 1.4 μg/g]), on where the birds were collected on the Great Salt Lake (Antelope Island, 8.6 ± 0.5 μg/g; Stansbury Island, 15.2 ± 1.4 μg/g), and on the grebe's age (juveniles, 8.5 ± 1.5 μg/g; adults, …

Do Sharp-Tailed Grouse Select Loafing Sites To Avoid Visual Or Olfactory Predators?, Michael R. Conover, Jennifer S. Borgo

Wildland Resources Faculty Publications

Grouse should seek loafing sites hidden from predators; however, good hiding sites from predators that use vision to locate prey differ from good hiding sites from predators that use odor to locate prey. We compared characteristics of control sites to sites used for loafing by sharp-tailed grouse (Tympanuchus phasianellus) to determine whether selection of loafing sites was more influenced by the need to hide from visual or olfactory predators. Sites used for loafing were similar to control sites in characteristics that would help hide a grouse from visual predators (i.e., visual obstruction, lateral visibility, visual obstruction, cover ht, and surface …

Selenium And Mercury Concentrations In California Gulls Breeding On The Great Salt Lake, Utah, Usa, Michael R. Conover, Josh L. Vest

Wildland Resources Faculty Publications

We examined selenium (Se) and mercury (Hg) concentrations in adult California gulls (Larus californicus) nesting on the Great Salt Lake, Utah, USA, during 2006 and 2007. During 2006, the mean Se concentration (± standard error) was 18.1 ± 1.5 μg/g in blood on a dry-weight basis and 8.1 ± 0.4 μg/g in liver. During 2007, Se concentrations were 15.7 ± 1.5 μg/g in blood and 8.3 ± 0.4 μg/g in liver; Hg concentrations were 2.4 ± 0.3 μg/g in blood and 4.1 ± 0.5 μg/g in liver. Gulls collected from a freshwater colony located within the watershed of the Great …

Gang Brooding In Canada Geese: Role Of Parental Condition And Experience, Michael R. Conover

Wildland Resources Faculty Publications

Some Canada Geese (Branta canadensis) raise their broods by themselves (two-parent families), while others raise them in gang broods, defined as two or more broods amalgamated into a single cohesive unit and shepherded by four or more parents. From 1984 to 2005, I individually marked Canada Geese in New Haven County, Connecticut, so that I could compare the characteristics of adults that raise their goslings in gang broods to those of adults that raised their goslings in two-parent families. I wanted to determine if a parent's decision to form a gang brood was influenced by its age or body mass, …

Direct And Indirect Effects Of Climate Change On A Prairie Plant Community, Peter B. Adler, James Leiker, Jonathan M. Levine

Wildland Resources Faculty Publications

Background

Climate change directly affects species by altering their physical environment and indirectly affects species by altering interspecific interactions such as predation and competition. Recent studies have shown that the indirect effects of climate change may amplify or counteract the direct effects. However, little is known about the the relative strength of direct and indirect effects or their potential to impact population persistence.

Methodology/Principal Findings

We studied the effects of altered precipitation and interspecific interactions on the low-density tiller growth rates and biomass production of three perennial grass species in a Kansas, USA mixed prairie. We transplanted plugs of each …

Aspen Succession And Nitrogen Loading: A Case For Epiphytic Lichens As Bioindicators In The Rocky Mountains, Usa, Paul C. Rogers, Kori D. Moore, Ronald J. Ryel

Wildland Resources Faculty Publications

Question: Can lichen communities be used to assess shortand long-term factors affecting seral quaking aspen (Populus tremuloides) communities at the landscape scale? Location: Bear River Range, within the Rocky Mountains, in northern Utah and southern Idaho, USA. Method: Forty-seven randomly selected mid-elevation aspen stands were sampled for lichens and stand conditions. Plots were characterized according to tree species cover, basal area, stand age, bole scarring, tree damage, and presence of lichen species. We also recorded ammonia emissions with passive sensors at 25 urban and agricultural sites throughout an adjacent populated valley upwind of the forest stands. Nonmetric multidimensional scaling (NMS) …

Environmental Variation, Stochastic Extinction, And Competitive Coexistence, Peter B. Adler, John M. Drake

Wildland Resources Faculty Publications

Understanding how environmental fluctuations affect population persistence is essential for predicting the ecological impacts of expected future increases in climate variability. However, two bodies of theory make opposite predictions about the effect of environmental variation on persistence. Single‐species theory, common in conservation biology and population viability analyses, suggests that environmental variation increases the risk of stochastic extinction. By contrast, coexistence theory has shown that environmental variation can buffer inferior competitors against competitive exclusion through a storage effect. We reconcile these two perspectives by showing that in the presence of demographic stochasticity, environmental variation can increase the chance of extinction while …

Quantitative-Genetic Variation In Morphological And Physiological Traits Within A Quaking Aspen (Populus Tremuloides) Population, Megan K. Kanaga, Ronald J. Ryel, Karen E. Mock, Michael E. Pfrender

Wildland Resources Faculty Publications

Genetic diversity within populations is an important component of adaptive evolution, and recent research has demonstrated that genetic variation within plant populations can have important ecological effects. In this study, we investigate quantitative-genetic variation in several traits within a quaking aspen (Populus tremuloides Michx.) population. A common garden experiment was planted with replicates of 13 aspen genotypes collected from wet and dry sites within a population in southern Utah, USA. Ten growth, leaf, physiological, and structural traits were measured. There were significant, heritable phenotypic differences among genotypes in every measured trait and differences in 4 of the 10 traits among …

Does Removing Coyotes For Livestock Protection Benefit Free-Ranging Ungulates?, Justin L. Harrington, Michael R. Conover

Wildland Resources Faculty Publications

We studied the effects of coyote (Canis latrans) control for livestock protection on native ungulates during 2003 and 2004 on 7 sites in Utah and Colorado, USA, totaling over 1,900 km2. We found no relationships between coyote control variables and offspring/female deer ratios. However, control effort (no. of hr spent aerial gunning for coyotes) and success (no. of coyotes taken) were positively correlated with numbers of mule deer (Odocoileus hemionus) and pronghorn (Antilocapra americana) observed per kilometer of transect. Our results suggest that coyote control for livestock protection may increase densities of mule deer and pronghorn in areas where it …

Influence Of Population Reduction On Predator Home Range Size And Spatial Overlap, Shandra Nicole Frey, Michael R. Conover

Wildland Resources Faculty Publications

The increasing populations of red foxes (Vulpes vulpes), raccoons (Procyon lotor), and striped skunks (Mephitis mephitis) in the Intermountain West have contributed to low waterfowl recruitment in recent decades. This effect prompted the need for predator removal at many waterfowl refuges, such as the Bear River Migratory Bird Refuge (BRMBR) in the Great Salt Lake ecosystem. Our study examined the effects of the removal of predatory mammals at the BRMBR on the home range size and spatial overlap of the remaining populations of red foxes, raccoons, and striped skunks. The removal of predators through traps, snares, and night-shooting created a …

Spatially Scaled Response Of A Lazuli Bunting Population To Fire, Michael L. Wolfe, Andreas Leidolf, Tim Nuttle

Wildland Resources Faculty Publications

We examined the response of Lazuli Bunting (Passerina amoena) to fire in Gambel oak (Quercus gambelii) woodland at Camp Williams, Utah, during 1993–1998. Overall, Lazuli Bunting abundance on the study area increased significantly during the 2 years after a stand-replacing wildfire, which covered 800 ha of Gambel oak woodland. This increase suggested that Lazuli Buntings respond positively to fire. However, a comparison of pre- and post-fire abundance of Lazuli Bunting for 2 groups of monitoring plots with different fire histories showed that abundance was significantly greater during the post-fire period for both burned and unburned plots. …

Deer-Vehicle Crash Hotspots In Utah: Data For Effective Mitigation, Chris Kassar, John A. Bissonette

Wildland Resources Faculty Publications

Animal-vehicle collisions and their associated ecological impacts have been reported since at least the early 1920s and continue to be of national and international concern today. Over 1 million deer-vehicle crashes may occur each year in the United States. On average, ~2,300 deer are reported killed on Utah highways each year. Reported numbers of deer-vehicle collisions may be conservative because only from ½ to 1/6 of deer vehicle collisions that occur are actually reported to authorities. The number of wildlife-vehicle collisions continues to grow with increasing urban and suburban development, growing numbers of vehicle miles traveled per year (VMT), and …

Mammal Abundance Indices In The Northern Portion Of The Great Basin, 1962-1993, Frederick F. Knowlton, Rebecca A. Bartel, L. Charles Stoddart

Wildland Resources Faculty Publications

Indices of abundance of selected mammals were obtained for two study areas within the Great Basin: the Idaho National Engineering and Environmental Laboratory, Idaho, and Curlew Valley, Utah, USA. Data collection occurred biannually 1962–1993, with varying durations among species and sites. Abundance indices were obtained for coyotes (Canis latrans), lagomorphs (primarily black-tailed jackrabbits, Lepus californicus), and eight species of rodents. Data were originally gathered as part of a long-term study of interactions among predator and prey populations, concentrating on aspects related to coyotes and black-tailed jackrabbits. Secondarily, these data are useful in portraying trends in mammal abundance …

Vegetation Exclosures In Utah: What Can They Tell Us About Long-Term Range Trends?, William A. Adair, John A. Bissonette

Wildland Resources Faculty Publications

Exclosures are flexible range management tools that can be used to simultaneously:

• Clarify conflicts between wild and domestic herbivores and their advocates;

• Evaluate herbivore influence on range productivity and composition;

• Monitor long-term trends and changes in range condition; and

• Identify the normal range of variation characteristic of natural plant communities.

What Makes An Animal Choose A Forage, Elizabeth A. Burritt, Frederick D. Provenza

Wildland Resources Faculty Publications

Consider the following scenarios: To cut the costs of ranching a researcher explores feeding cattle ammoniated straw in winter. Some of the cows maintain themselves on the diet while others lose weight, produce less milk and fail to conceive. A producer in Missouri plants a pasture rich in legumes and high in crude protein, yet his cattle prefer moldy hay and endophyte infected tall fescue to the legumes. Why do animals behave this way? Animals are thought to prefer foods that are palatable but what is palatability? We define palatability as the interrelationship between a food's flavor and postingestive feedback …

Development Of A Bird-Avoidance Model For Naval Air Facility El Centro, California, E. J. Zakrajsek, John A. Bissonette

Wildland Resources Faculty Publications

Bird-strikes (collisions between birds and aircraft) pose a significant threat to aviation safety. Naval Air Facility El Centro, CA lost an F-18 jet to a bird strike in October 1995. To help combat this threat we developed a bird-avoidance model as a risk management tool to help the Navy plan training flights in areas and during times of low bird activity at the installation. The calculated bird-strike risks were published as a web page to be maintained on the installation’s internet server for easy access by flight crews, flight-safety officers, airfield managers, natural resource managers, and other Navy personnel.

Modelling Age- And Density-Related Gas Exchange Of Picea Abies Canopies In The Fichtelgebirge, Germany, Eva Falge, John D. Tennhunen, Ronald J. Ryel, Martina Alsheimer, Barbara Köstner

Wildland Resources Faculty Publications

Differences in canopy exchange of water and carbon dioxide that occur due to changes in tree structure and density in montane Norway spruce stands of Central Germany were analyzed with a three dimensional microclimate and gas exchange model STANDFLUX. The model was used to calculate forest radiation absorption, the net photosynthesis and transpiration of single trees, and gas exchange of tree canopies. Model parameterizations were derived for six stands of Picea abies (L.) Karst. differing in age from 40 to 140 years and in density from 1680 to 320 trees per hectare. Parameterization included information on leaf area distribution from …

Synecology And Disturbance Regimes Of Sagebrush Steppe Ecosystems, Neil E. West

Wildland Resources Faculty Publications

The pre-Columbian mixed-growth form, composition, and structure of sagebrush steppes was mostly due to the highly variable semiarid climate and long fire-free intervals. The weak stability of this relatively complex vegetation was easily upset by excessive livestock grazing, especially in drought periods. After a few decades of uncontrolled livestock grazing, it was easy for introduced winter annuals, especially cheatgrass, to dominate the understory and alter the fire regime to larger, more frequent fires that occur earlier in the year. Accelerated soil erosion has caused many sites to lose the potential for management back toward native perennial dominance by controlling only …

Response Of Coyotes To Avian Distress Calls : Testing The Startle-Predator And Predator-Attraction Hypotheses, Frederick F. Knowlton, Michael R. Conover, Kristi K. Wise

Wildland Resources Faculty Publications

We tested two hypotheses proposed to explain why many birds emit distress calls when in the grasp of a predator: the startle-predator and predator-attraction hypotheses. Responses of captive coyotes to a starling distress call were compared between no-call and call trials to determine whether coyotes are startled by the call, and if so, whether they habituated to it. The coyotes were then paired and re-tested to determine whether the call incites a second coyote to approach and interfere with the attack of the initial coyote. Most coyotes exhibited a startle response during their first exposure to the distress call, their …

Methods In Historical Ecology: A Case Study Of Tintic Valley, Utah, Jeffrey A. Creque, Neil E. West, James P. Dobrowolski

Wildland Resources Faculty Publications

Through use of repeat photography, archival research, and field observation to reconstruct landscape vegetation patterns and changes across a 120 year period in the upper Tintic Valley of central Utah, researchers found significant changes in landscape vegetation pattern over time, including change in pinyon-juniper woodland area. Previously reported massive woodland harvest associated with early mining, domestic and agricultural activities elsewhere in the Intermountain West also took place in Utah. The impact on woodland area of the agricultural "bull" fence alone was significant. More recent study area woodland expansion also occurred. Because intensive industrial activity associated with development of the Tintic …

Understory Succession Following A Dieback Of Myrica Faya In Hawai’I Volcanoes National Park, Peter B. Adler, Carla M. D'Antonio, J. Timtohy Tunison

Wildland Resources Faculty Publications

Studies of invasion by the introduced nitrogen-fixing tree Myrica faya Aiton in Hawai'i Volcanoes National Park have led to predictions that the nitrogen-rich soil M. faya creates will promote invasion by nonindigenous plant species. An insect-caused dieback of M. faya that began in the late 1980s provides an opportunity to test this hypothesis. We compared· percentage cover and density of all plant species under live and dead M. faya, as well as total nitrogen in soil and plant tissue. Mean percentage cover of four common species increased significantly, and no species decreased in cover after dieback. Cover of native …

Dispersal Patterns Of Subadult And Adult Colorado Squawfish In The Upper Colorado River, D. B. Osmundson, Ronald J. Ryel, M. E. Tucker, D. B. Burdick, W. R. Elmblad, T. E. Chart

Wildland Resources Faculty Publications

Abstract.—We investigated distribution and dispersal patterns of subadult and adult Colorado squawfish Ptychocheilus lucius (recently renamed the Colorado pikeminnow) throughout their range in the upper Colorado River. Annual, river-wide, capture–recapture data were used to document movements during a 5-year period (1991–1995). Average total length of Colorado squawfish progressively increased upstream: juveniles and subadults occurred almost exclusively in the lowermost 105 km of the 298-km study area, whereas most adults were concentrated in the uppermost 98 km. This was most pronounced early in the study and less so later due to the effect of two or three strong year-classes that dispersed …

Growth And Survival Of Colorado Squawfish In The Upper Colorado River, D. B. Osmundson, Ronald J. Ryel, T. E. Mourning

Wildland Resources Faculty Publications

Growth and adult survival rates were estimated for the endangered Colorado squawfish Ptychocheilus lucius inhabiting the upper Colorado River by using data from fish captured during 1990–1995. Mean annual growth rates of fish aged 3–6 years ranged from 32.2 (age 6) to 82.0 (age 3) mm/year. Growth rates for older fish were highest for fish 400–449 mm total length, TL, (42.7 mm/year) and declined to 19.8 mm/year for fish 500–549 mm TL. Fish 550 mm and longer grew an average 9.5 mm/year. Survival rates for fish 550 mm and longer were estimated by comparing measured size distributions with simulated stable …

Correlations Of Phenolic Acids And Xylose Content Of Cell Wall With In Vitro Dry Matter Digestibility Of Three Maturing Grasses, Elizabeth A. Burritt, A. S. Bittner, J. C. Street, M. J. Anderson

Wildland Resources Faculty Publications

Maturing reed canarygrass, Russian wildrye, and smooth bromegrass cell walls were analyzed for lignin, phenolic acids, and neutral sugars. Linear correlation between in vitro dry matter digestibility and the p-coumaric acid content was −.86. The correlation between in vitro dry matter digestibility and ratio of p-coumaric to ferulic acid was −.84. Samples with high percentages of lignin also contained high ratios of p-coumaric to ferulic acid. Thus, p-coumaric acid may be more important than ferulic acid in crosslinking lignin to structural carbohydrates. Percent xylose and in vitro dry matter digestibility also were correlated significantly in all three species. A Russian …

A Track Plot System To Monitor Habitat Use, Richard A. Ockenfels, John A. Bissonette

Wildland Resources Faculty Publications

Difficulty in capturing a sufficient sample of white-tailed deer (Odocoileus virginianus) for a biotelemetry habitat use study led to the development of an alternative method using track plots. One-hundred 1 X 3 m plots/site were proportionately allocated by percentage area of distinct cover types, prior to random location in the 3 study areas. Results from 13 months of use indicated that the method was acceptable for monitoring habitat use patterns. Potential uses and problems are discussed. Comparisons with biotelemetry and direct observation data are made.

Estimates Of White-Tailed Deer Activity Levels In Oklahoma, Richard A. Ockenfels, John A. Bissonette

Wildland Resources Faculty Publications

White-tailed deer (Odocoileus virginianus) activity levels were estimated by track counts on 3 study sites in the Cross Timbers region of Oklahoma during 1978-79. An activity index (number of tracks/day) was developed from repetitive readings of 100 track plots (1 x 3 m) per site. Significant differences (P < 0.05) in monthly activity levels were found. Within-month and between-month variability was influenced by land-use patterns, ambient temperature shifts, changes in food resource availability, and deer behavior patterns. A seasonal bimodal pattern was observed, with peaks during late spring and fall-early winter, while lowered activity was observed during early spring and summer.

Interacting Prey Characteristic Effects On Kestrel Predatory Behavior, Frederick F. Knowlton, Leonard F. Ruggiero, Carl D. Cheney

Wildland Resources Faculty Publications

Prey selection was assessed based on 116 experimental trials in which six kestrels were presented pairs of mice. Independent variables included pelage color (black and white), morphology (familiar and unfamiliar), and movement (aberrant, normal, and none). Each prey item represented a combination of three treatments, i.e., one per variable. In general, black pelage was preferred to white and familiar morphology was preferred to unfamiliar. An important interaction occurred between movement and morphology. Kestrel selection was low for moving unfamiliar prey but high for nonmoving unfamiliar prey. The highest rates of attack were elicited by moving familiar prey. It was concluded …