Multiyear drought is expected to increase in occurrence and severity in dry regions across the world, such as the American Southwest, endangering native species and ecosystem health. The effects of multiyear drought are often worsened by human water use for consumption, energy production, and agriculture, which, in lakes and reservoirs, cause reduced lake elevation. Reductions in lake elevation may leave previously submerged habitat stranded along shorelines and make tributaries inaccessible to fishes. Here, we show that decreasing lake elevation, associated with drought and water withdrawal, reduces the availability of shoreline cobble habitat to fishes and increases tributary distance by creating an elevation-specific shoreline habitat map and an elevation-specific tributary channel distance map, respectively. We combined 17-years of fish survey data and lake elevation history with our elevation-specific maps to determine whet her the number of fishes observed and the number of fish hatching are related to drought-driven changes in shoreline habitat and tributary channel distance. We surveyed the shoreline zone of Bear Lake, UT-ID, from full pool to a depth of >18m, totaling 94.86 surveyed km2. As lake elevation decreased >6 m from full pool to the lowest historical elevation, shoreline cobble decreased by >97%, and tributary channel distance increases up to 400% that of full pool. Bear Lake sculpin, a cold-water fish species of concern that relies on cobble for spawning, catch per unit effort decreased by >75% at the minimum cobble area available, and the number of sculpin successfully becoming adults declined by as much as 86%. The number of Bear Lake Bonneville cutthroat trout, a sport fish that relies on connections between tributaries and the lake to complete their life cycle, successfully becoming adults declined by as much as 62%, but annual growth was not related to drought. Our research is an example of the severe consequences of multiyear drought conditions and water withdrawal on lakes and reservoirs, as well as the fishes they support. Indeed, understand the effects of extended drought on aquatic habitats is critical to maintain healthy lakes and reservoirs, to sustain native species, and to maintain the health of popular sport fisheries.

Policies regulating wildlife winter-feeding programs may have long-term impacts on conservation and future management of both target and non-target species. In 2000, the Utah Wildlife Board, upon reviewing input from a series of public regional meetings, adopted a Utah Big Game Winter-Feeding Policy. The Utah Division of Wildlife Resources used this policy to regulate winter-feeding programs for mule deer in northern Utah, 2001-2005. I monitored the program effects on mule deer biology, activity and migration, and winter browse utilization and productivity. While feed rations generally compensated for protein and energy deficiencies, they may overlook mineral deficiencies. To determine if mule deer could select for feeds that contained minerals that may be deficient in native browse, I conducted experimental feeding trials using copper supplements. Feeding program success on increasing mule deer winter survival depends heavily on timely implementation. Therefore, I evaluated the utility of a modified body condition index to use deer-vehicle collision carcasses to monitor herd nutritional status, and applied this information to weather data to assist in determining when to implement winter-feeding programs. Lastly, I surveyed a random sample of Utah stakeholders to determine if the policy developed through the regional meeting process reflected wider public opinion rather than traditional consumptive users. This winter-feeding enhanced body condition, and increased adult female survival. When dynamics of fed and non-fed study groups were modeled over five years, the model predicted both populations were declining, with a lower rate of decline in the fed population. The primary cause of mortality for fed and non-fed groups, deer-vehicle collision, nullified benefits accrued from feeding. Deer may have balanced the effects of sagebrush and bitterbrush toxins with nutrients from feed rations, thus resulting in increased browsing of bitterbrush. Fed deer browsed over less area, and migrated earlier in fall and later in spring. Mule deer also selected a consistent proportion of copper-amended rations, suggesting plain rations are nutritionally inadequate. Although most Utah stakeholders were unaware of Utah's big game winterfeeding policy, most believed winter-feeding was an important mule deer management strategy in Utah. When given a choice between using management funds to support winter-feeding or habitat projects, stakeholders preferred funding habitat restoration.

Ecological communities are complex, the structure of which is composed of interactions between multiple community characteristics and the abiotic and biotic factors shaping them. Because of this complexity, ecological studies are generally limited in scope and size, often dissecting communities into their component parts to examine them piece by piece. While this might be the most practical method to study communities, this approach often neglects other characteristics that, with their inclusion, would provide a more complete picture of community ecology. The studies described in this dissertation were conducted in an effort to synthesize the complexity that is inherent in ecological plant communities growing on a Mojave Desert bajada. Each study addresses a separate component of community structure, which, taken as a whole, provides a more thorough understanding of arid plant community dynamics. Overall, our results reveal the importance of substrate variables and their role in shaping plant community structure in arid environments. In addition, these investigations provide evidence of the strong role that facilitation plays on this bajada and possibly arid plant communities as a whole. The comprehensive approach described in this dissertation will enable ecologists to gain a more complete understanding of community dynamics and apply this knowledge to various climate change and land management scenarios.

Virus diseases of stone fruit orchards have existed in Utah for more than a quarter of a century and are seriously diminishing the peach and cherry fruit production. Western X of peach, rusty mottle of cherry, wilt and decline of cherry, and little cherry constitute the most economically important stone fruit virus diseases in Utah. Many orchards, particularly in Davis County, have 50 to 83 percent of the trees infected with one or more of the yellow-red viroses. Surveys have shown that the diseases are spreading from 3 to 5 percent each year. It is believed that certain insects are responsible for the natural spread of the virus diesases of stone fruits. Some inconclusive evidence points to leafhoppers as the potential vectors since many cicadellidids are capable of transmitting virus to plants during the feeding process. They have maintained a reputation for being efficient vectors of plant viruses for many years, as well as inducing other types of plant injury. Their adaptable, piercing-sucking mouth parts inoculate plants with filterable viruses taken in from infected plants. They inflict other types of damage to the host by injecting toxic substances. The most sever type of damage, however, is that caused through the virus infection which generally is systemic. The purpose of this investigation was to determine the occurrence, seasonla abundance, and host preference of leafhoppers occurring in the stone fruit orchards of northern Utah. Leafhopper occurrence in plant environs adjacent to the stone fruit orchards was also studied. Studies were made to determine if any correlation existed between leafhopper abundance and percentage of diseased trees in the orchards. Trap studies and surveys seemed to be the most appropriate technique in approaching this problem. The trap studies were conducted in fifteen stone fruit orchards in five counties of norhtern Utah. Surveys were undertaken in most stone fruit growing areas in the northern part of the state.

Investigation of primary production in streams and rivers has lagged behind similar investigations in marine and lacustrine environments. Recently, however, Odum (1956) has demonstrated methods that allow the estimation of productivity of most moving waters. For reasons discussed later in this paper, Odum's method is not satisfactory for shallow, very rapid rivers as typified by Logan River. The present investigation then was primarily an exploration of a method possibly applicable to measurement of productivity in shallow rapid rivers. Investigation of phases of the ecology and distribution of the main contributors to primary production, the benthic algae, was a necessary corollary to intelligent measurement of primary production in Logan River. A recent review of the knowledge of ecology of river algae (Blum, 1956) summarizes this topic. Most quantitative investigations of river algae have been directly or indirectly concerned with indices of pollution rather than productivity (Jones, 1951) (Reese, 1937) (Patrick, 1949) (Butcher, 1932, 1940, 1945, and 1947). The growth of algae on slides has been a frequently used method of quantitative study, but it is difficult to relate values attained in this fashion to total productivity or standing crop. Statements concerning algal succession and seasonal variation based on counts of algae growing on glass slides in very rapid water appear questionable.

No description available.

No description available.

Predators use a variety of tactics with which to obtain prey. Here, I describe lingual luring by the mangrove saltmarsh snake (Nerodia clarkii compressicauda), a somewhat unique behavior that involves the use of the tongue to attract fish prey close enough to permit their capture. The lure is characterized by considerable upward curling of the distal portion of the tongue as it protrudes from the mouth. In addition, luring tongue flicks are significantly greater in duration than chemosensory tongue flicks. Both visual and chemical cues are sufficient to stimulate lingual luring, the latter more so than the former. However, both types of cues together have a strong synergistic effect on elicitation of the behavior. Luring behavior presents primarily a visual stimulus, as its frequency was reduced in the dark. Although prey density had no effect on the exhibition of luring by these snakes, prey density did have an effect on their activity level and their choice of foraging sites. N. c. compressicauda was a fairly active forager under the conditions tested in these studies, but its use of a largely sit-and-wait tactic such as predatory luring indicates that this species uses more of a mixed foraging strategy. The foraging behavior of the snakes differed at different levels of habitat structural density, created by using simulated prop roots in a laboratory arena. When no prop-root structure was present, the snakes rarely ventured into open water. However, they spent significantly more time in the water if prop roots were present. Such habitat structure may serve as protection from larger predators that may be impeded by it.

Groundfish distributions were examined in spring 2006 and 2007 in the northern Bering Sea around St. Lawrence Island (SLI). Arctic cod (Boreogadus saida), Bering flounder (Hippoglossoides robustus), and snailfish (Liparidae) were the dominant species south of SLI, whereas Arctic alligatorfish (Ulcina olrikii) and Arctic staghorn sculpin (Gymnocanthus tricuspis), or shorthorn sculpin (Myoxocephalus scorpius) were dominant north of SLI. The results indicate that bottom water (or water column) chlorophyll a and sediment parameters had greater influence on fish distribution in 2006 (cold, pre-bloom conditions), whereas bottom water temperature and sediment grain size were more important in 2007 (warm, bloom conditions) among a total of 14 environmental variables that were analyzed. These findings suggest strong linkages between physical conditions (e.g. water temperature and hydrography as it affects sediment grain size) and biological conditions (e.g. bloom status) in structuring fish communities in the northern Bering Sea. The diet and feeding relationship of six dominant groundfish, specifically Arctic cod, Bering flounder, snailfish, Arctic staghorn sculpin, Arctic alligatorfish, and shorthorn sculpin in the northern Bering Sea were studied using stomach content data in spring 2006 and 2007. All of Bering flounder had empty stomachs. Amphipods were the primary prey in five fish species characterized by feeding narrow niches except snailfish, which consumed a diverse diet. Arctic cod was the only occasional pelagic feeder; all the other fish studied were benthic feeders. High diet overlap was found among some fish species; however, competition was likely reduced by differences in feeding strategies and available food resources. Stable carbon and nitrogen isotopes of groundfish and their potential prey items were measured for trophic relationships and energy flow in the northern Bering Sea in 2006 and 2007. Lipid content impacts on stable isotope analyses were reduced using a mathematical normalization technique using C/N ratios. Values of del13C in fish species showed significantly different between seasons. Trophic levels (TL) were estimated by del15N values of fish and prey species with primary consumer as a baseline indicator. Bivalves and amphipods had the lowest TL values, 2.4 – 3.4, followed by polychaetes (TL = 3.6 – 4.1), and fish (TL = 3.5 – 4.6).

Excess adipose tissue is a risk factor for developing colorectal cancer. However, the present studies demonstrate that lack of adipose-derived factor(s), such as adiponectin, due to the substantial loss of body fat on high dairy calcium diet could increase susceptibility to intestinal tumorigenesis. These studies suggest that a minimum amount or threshold level of adipose tissue may be required to significantly attenuate tumorigenesis. In ApcMin/+ mice, consumption of high dairy calcium diet exhibited markedly reduced adipose tissue and increased tumor number. Our results showed that the high calcium diet reduced fat pad mass by 65%-82% in ApcMin/+ (p<0.03) in comparison with low calcium diet. ApcMin/+ mice on the high calcium diet exhibited an increase in tumor number (76 vs. 29, p=0.009). Moreover, β-catenin gene and cyclin D1 gene expression were significantly induced in intestinal tumor tissue of ApcMin/+ mice on high calcium diet. These effects were not directly resulted from high dietary calcium feeding, but rather associated with loss of body fat mass. Tumor load was not affected by the calcium diet on obese A/yApcMin/+mice despite the fact that high dairy calcium diet produced a substantial loss of body fat, as there was still substantial residual adipose tissue remaining. Our results indicate that protective effects of calcium against colorectal cancer may be least apparent among lean individuals, suggesting that future studies of calcium and colorectal cancer should consider stratification of subjects according to adiposity. In an in vitro environment to determine the adipose-derived factor(s) responsible, we utilized a co-culture system to observe the influence of human adipocytes on the growth of Caco-2, a human colon cancer cell line. We found that human adipocytes substantially suppressed proliferation of Caco-2 by 62.8%. In addition, we reported that human adipocyte conditioned medium inhibited growth of Caco-2 cells by 28.0%-65.6% compare to DMEM. These findings suggest the protective effect of adipocytes on colonic tumorigenesis. To further investigate if adiponecin, a protein hormone secreted from mature adipocytes, is responsible for this inhibitory effect, anti-human adiponectin-neutralizing antibody was added into the human adipocyte conditioned medium (HACM) and to the co-culture system. The antibody blocked the growth-inhibiting effects in both human adipocytes (HA) and HACM. Consistent with this, siRNA-mediated decrease in adiponectin protein in human adipocytes prevented the inhibitory effect of human adipocytes on Caco-2 proliferation. These data demonstrated that human adipocytes inhibit Caco-2 proliferation and that adiponectin is responsible for this effect.