Reliable quantities of blood can be sampled repeatedly from the lesser octopus Eledone cirrhosa (Lam. ) and the haemocytes cultured for up to 72 h. Sampling causes an increase in the number of haemocytes/ml, in the percentage of haemocytes containing cytoplasmic granules and a change in the staining pattern of the haemocytes. Sampling also causes a decrease in the amount of copper (mg/ml) in the haemolymph and an initial decrease in the amount of protein (mg/ml), which returns to the original values over extended sampling periods. The haemocytes from E. cirrhosa will phagocytose bacteria (Vibrio anguillarum) in vitro in the absence of haemolymph (dependent on the temperature and duration of incubation) but enhanced phagocytosis will occur in the presence of haemolymph (10- 100% concentration). Opsonization is also dependent on the temperature and on the duration of exposure of the bacterium to the haemolymph. Haemocytes migrate towards low concentrations of blood preparations, to lipopolysaccharide (LPS) and to preparations which had contained live bacteria. Haemocytes also have a bacteriostatic effect on the growth of live bacteria with the effect being dependent on the temperature, duration of the assay and the bacterial species used. Haemocytes also produce intracellular reactive oxygen species, detected by nitroblue tetrazolium, after incubation with dead bacteria in particular, but also live bacteria and LPS. E. cirrhosa haemolymph agglutinates the bacteria V. anguillarum, Y. parahaemolyticus and Aeromonas salmonicida and exerts a bacteriostatic effect on these bacteria which is dependent on the temperature, the amount of haemolymph present and the bacterial species used. The haemolymph, haemocytes and certain tissues from E. cirrhosa exhibit lysozyme and antiprotease activity. The injection of live V. anguillarum causes an increase in lysozyme activity in the branchial heart (after 48 h) and a decrease in the haemocytes (after 24 h). Antiprotease activity increased in the haemocytes (4 h) after bacterial injection but decreased in the haemolymph. Live bacteria caused an increase in the number of circulating haemocytes. The bacteria were cleared from the circulation of E. cirrhosa in about 4h by both the haemocytes and tissues (branchial heart, branchial heart appendage and white body) where they were degraded. The large vacuole in branchial heart cells changed in appearance 4h after bacterial injection and the haemocyte nucleus became pleomorphic. Colloidal graphite was aggregrated in blood vessels only.

No description available.

Master of Science / Division of Biology / David A. Haukos / The lesser prairie-chicken is a prairie grouse native to the southwestern Great Plains that has experienced significant population and habitat declines since European settlement. Ongoing declines prompted the U.S. Fish and Wildlife Service to list lesser prairie-chickens as threatened under the Endangered Species Act in spring of 2014. In fall of 2015, the listing was vacated on procedural grounds and the lesser prairie-chicken was removed from listing in summer 2016. Despite the legislative change, considerable conservation efforts emerged with the initial listing and have continued following the removal of the species from the threatened and endangered species list. Understanding how lesser prairie-chickens use landscapes and how management actions can influence their space use is important for long-term strategies to meet conservation goals. I modeled lesser prairie-chicken habitat selection relative to landscape mosaics of vegetation patches generated through patch-burn grazing, microclimate, and vegetation characteristics across their range. I captured, attached GPS satellite or VHF radio transmitters to, tracked, and measured vegetation characteristics used by and available to female lesser prairie-chickens across the northern portion of their range in Kansas and Colorado. Female lesser prairie-chickens use all patch types created in a patch-burn grazing mosaic, with female selecting greater time-since-fire patches (>2-years post-fire) for nesting, 2-year post-fire patches during the spring lekking season, 1- and 2-year post-fire patches during the summer brooding period, and 1-year post-fire units during the nonbreeding season. Available vegetation structure and composition in selected patches during each life-cycle stage was similar to the needs of female lesser prairie-chickens during that life-cycle stage. To assess their selected microclimate conditions, I deployed Maxim Integrated Semiconductor data loggers (iButtons) at female flush locations and across a landscape inhabited by lesser prairie-chickens. Females selected locations that minimized thermal stress at microsite, patch, and landscape scales during peak midday temperatures during summer. Females selected midday locations based on vegetation characteristics; where selected sites had >60% forb cover and <25% grass cover, or >75% grass cover and <10% forb cover. In addition, females selected sites with greater visual obstruction. I measured vegetation composition and structure at use and available sites at four study areas located along the precipitation gradient characterizing the full extent of the lesser prairie-chicken range. Vegetation structure use by females varied in relation to long-term precipitation patterns. Females used sites with lower visual obstruction than available during the fall and spring. However, they used vegetation composition that was similar to available within each study area. Overall, my findings indicate that lesser prairie-chickens require structural and compositional heterogeneity to support a suite of habitat needs throughout the year. Therefore, management should focus on providing structural and compositional heterogeneity across landscapes. Greater heterogeneity in vegetation conditions can be achieved through management practices that allow domestic grazers to select grazing locations, such as patch-burn grazing or increased pasture area.

Thesis (M.Sc.)--University of the Witwatersrand, Faculty of Science, 1969.

In order to determine the impact of lesser snow goose (Chen caerulescens caerulescens) herbivory on above and belowground nutrient dynamics, a grazing and nutrient addition experiment was conducted in two habitat types utilized by snow geese near Churchill, Manitoba. Forage plant nutrition, soil microbial biomass, and inorganic and organic soil nutrients were measured in relation to the timing of grazing, over two consecutive summers. Soil was collected from the rhizosphere to determine the influence of foliar herbivory on root-microbe interactions. Primary productivity in both habitats is co-limited by the availability of both nitrogen (N) and phosphorus (P). Aboveground defoliation either caused a reduction or no change in soil microbial biomass nutrients (carbon (C), N, or P). Defoliated shoots had higher N concentrations and did not show compensatory growth within the season. Root biomass was somewhat reduced with grazing, but higher whole plant N content suggests that grazing does not compromise N-uptake.

In order to determine the impact of lesser snow goose (Chen caerulescens caerulescens) herbivory on above and belowground nutrient dynamics, a grazing and nutrient addition experiment was conducted in two habitat types utilized by snow geese near Churchill, Manitoba. Forage plant nutrition, soil microbial biomass, and inorganic and organic soil nutrients were measured in relation to the timing of grazing, over two consecutive summers. Soil was collected from the rhizosphere to determine the influence of foliar herbivory on root-microbe interactions. Primary productivity in both habitats is co-limited by the availability of both nitrogen (N) and phosphorus (P). Aboveground defoliation either caused a reduction or no change in soil microbial biomass nutrients (carbon (C), N, or P). Defoliated shoots had higher N concentrations and did not show compensatory growth within the season. Root biomass was somewhat reduced with grazing, but higher whole plant N content suggests that grazing does not compromise N-uptake.

Lesser prairie chicken (Tympanuchus pallidicinctus) numbers have declined considerably in Texas since the early 1900s. Conversion of native prairie to cropland has been the major cause of the decline. I trapped and monitored 115 (66 males, 49 females) lesser prairie chickens in the Rolling Plains of the Texas Panhandle from 2001 through 2003. I used an information-theoretic approach to model selection as implemented in program MARK to evaluate factors contributing to variation in survival and differences in nest success. I found breeding season survival of both males and females was lower compared to non-breeding season survival. Annual survival was 0.52 (95% CI: 0.32? 0.71). Model selection indicated higher nest success (70%) in the sand sagebrush (Artemisia filifolia) vegetation type as compared to the shinnery oak (Quercus harvardii) type (40%). I also evaluated post-burn habitat alterations and plant succession (1 year and 2 years after burning) as potential lesser prairie chicken habitat. After spring rainfalls stimulated re-growth of herbaceous plants, male lesser prairie chickens moved to the site, feeding on new-emerging forbs throughout the summer. A female lesser prairie chicken with a brood used the burned site during the first summer after the burn. A year later, males established a lek on the burned site. Two female lesser prairie chickens with broods used the burned site during the second summer. Burned sites had more forbs than nonburned sites and probably had more insects available which are an important food source for chicks during their first 4?5 weeks of age.

A nationwide mail survey was conducted among importers and other members of the supply chain linked to the importation of tropical hardwood products to assess the market potential for Bolivian lesser-known wood species (LKS) in the U.S. market. One hundred and eleven companies responded to the questionnaire and provided information on their interest in importing lesser-known wood species, their willingness to pay for a Bolivian wood species substitute, percentage of their imports that are environmentally certified, and important factors considered to try new wood species. The results indicate that tropical hardwoods represent 33% of the product mix of companies that purchased wood products. Typically, companies imported less than 100 MBF in 2006. Sawnwood was the product that was imported the most, followed by plywood, veneer and flooring. Six Bolivian LKS are among the top 16 new wood species purchased by respondent companies in 2006 and three Bolivian LKS are part of the top 12 common tropical wood species imported in the U.S. Sixty-seven percent of overall respondents stated that they have plans to increase the imports of tropical hardwoods in 2007. Typically, members of the supply chain tried 1 to 2 new wood species in 2006. Retailers were the sector that tried the most, on average 5 new species. Price and availability were the major reasons to try new wood species. A MS-Access database was developed that allows comparisons of 20 potentially marketable Bolivian LKS with 10 common U.S. domestic hardwoods and 20 common tropical hardwoods imported into the U.S. Finally, strategic marketing recommendations are suggested to promote Bolivian LKS in the U.S. Results indicate that there are good opportunities for Bolivian LKS in the U.S market. / Master of Science

Thesis (Ph.D.)--University of Delaware, 2005. / Principal faculty advisor: Cathy Matson, Dept. of History. Includes bibliographical references.

Master of Science / Department of Biology / David A. Haukos / Abstract–Duckling Survival Lesser scaup (scaup) populations have been experiencing continent-wide decline since the 1980s. It is important to have complete understanding of the critical factors influencing population change (e.g., duckling survival, nesting success, and health) to advance our understanding of population dynamics and improving species conservation. Duckling survival is a primary driver of scaup demography. I conducted a capture-mark-recapture study using Cormack-Jolly-Seber models in Program MARK to compute apparent daily survival and recapture probabilities for 3256 individually marked ducklings with 620 recaptures during 2010 to 2013. The most parsimonious survival model based on a priori hypotheses found that Julian hatch date squared was the most significant predictor of survival and consistent through all four years. Mass at hatch also was significant as a quadratic effect. Duckling survival to 30 days ranged from 29.0 to 80.0. During this study, stabilizing selection played a significant role in duckling survival, which indicates that there was trade-offs for selection of an optimal timing of hatch on survival and a cost associated with hatching too early or too late and being too heavy or to light. / Abstract–Nest-Site Selection There is a hierarchical process of behavioral and environmental processes that influence habitat selection, which inherently influences the survival and fitness of that individual and contributes to population growth. I investigated nest fate, spatial attributes, and all relationships between high and low-water levels with habitat attributes (distance to upland, distance to open water, nearest neighbor distance) of located nests using general linear models in SAS, t-tests in R, and Hot Spot Analysis in ArcGIS of 481 nests over eight years. In low-water years, successful nests (X̅ = 1153 m) were located 22.0% farther from upland than unsuccessful nests (X̅ = 944 m), but support for a similar relationship was lacking in high-water years. Successful nests were located 21.0% and 23.0% (i.e., 49 and 50 m) closer to conspecific nests than unsuccessful nests in low and high-water levels, respectively. In both high and low-water level years, clusters of nests initiated later in the season coincided with Hot Spots for nest fate (i.e., high-quality habitat patches, clusters of successful nests), whereas areas that tended to be selected first, evidenced by clusters of nests initiated earlier, tended to overlap with clusters of Cold Spots for nest fate. The core Hot Spot for nest fate was in the same spot in both water level conditions and located in flooded emergent vegetation in the heart of Lower Red Rock Lake furthest from any upland habitat. Three out of six Cold Spots for nest fate both in high and low-water years were located in emergent vegetation on the perimeter of Lower Red Rock Lake adjacent to uplands. Density-dependence seems to be a factor affecting late-nesting scaup females that are apparently cuing in on the reproductive performance of conspecifics when determining where to nest. Therefore, management actions focused on survival and reproductive success of scaup should consider managing water levels and habitat for later nesting scaup to increase adult survival and ultimately recruitment of ducklings. / Abstract – Blood Parasite Prevalence Blood parasites, per se, do not lead to direct mortality, but instead reduce the health of individual birds, which may ultimately lead to decreased reproductive success. Evidence has shown that presence of blood parasites can reduce fitness, body condition, and reproductive success of waterfowl. For many avian species, the cost of reproduction is manifested as a negative relationship between female breeding effort and breeding season survival, with trade-offs occurring when these adaptive choices become detrimental to future reproductive performance. Blood was drawn for parasite load determination from 112 individual adult scaup captured from 2011to 2012 via spotlighting and drive-trapping. Parasite prevalence was determined through blood assays that were created using a two-slide wedge technique. Relationships among seasonal heterophile:lymphocyte ratio (a proxy for health), body mass at time of capture (throughout pre-, during, and post-breeding periods), breeding status (females only), and Julian date of capture (date of capture) of capture with parasite prevalence were analyzed using linear (lm) regression models in R 2.15.2. The blood parasite infection rate was 5.0%, with prevalence differing by gender with 33.3% of males positive for blood parasites compared to 1.0% of females. The presence of blood parasites did not affect health, fitness, or breeding status of scaup. A quadratic relationship was found with body mass and date of capture, indicating that body mass increased from pre-breeding period to the breeding period and decreased significantly at the end of the summer during molt. A negative relationship between the heterophile:lymphocyte ratio of female scaup and date of capture (i.e., the health of scaup females was greatest during the pre-breeding period after which it consistently decreased until the molting period). A strong negative correlation between heterophile:lymphocyte ratio and body mass was found in both genders, which indicated that scaup in poor body condition were also in poor health at the end of the breeding season.