It is an unresolved paradox that non-native species are successful in novel environments whereas native species, presumably adapted to that environment, decline. This knowledge gap has persisted because third party processes in invasion ecology have been overlooked. Ungulate densities are increasing due to the eradication of predators and landscape change and I asked how herbivory and invasion might interact to cause declines of native species. In Garry oak meadows, Canada’s most endangered ecosystem, native forbs have declined relative to non-native grasses and I tested the facilitatory role of herbivory in that degradation. My investigations, novel to the field, were conducted on islands spanning the Canada-US border. Islands served as natural experimental units in a mensurative study of abundance patterns in seven plant groups and 15 focal species along gradients of herbivory, biogeography, soil depth, and human activities. Increasing ungulate densities were related to declines in abundances of native forbs, and increasing abundances of non-native annual grasses. These regional patterns were upheld by two plot-based, 2x2 factorial experiments that contrasted the fitness of native species under manipulations of herbivory and competition for light. Specifically, I showed that ungulates limited the establishment, growth, survival and reproduction of seedlings and transplanted native forbs and shrubs and that competition from non-native species had little effect. I also calculated forage selectivity indices and tested the efficacy of fencing and cutting to reduce competition, for the restoration of native community biomass. Non-native annual grasses were rarely browsed and increased with increasing ungulate density. Non-native perennial grasses declined with herbivory, however, their regional abundances were unaffected by ungulate density despite being preferentially foraged. That non-native annual and perennial grasses differed in their responses to herbivory has consequences for restoration and illustrates the challenge of developing a comprehensive theory of invasion. Reducing ungulates, necessary for the recovery of native forbs, also benefits non-native perennial grasses and therefore their removal speed recovery of Garry oak meadows. Despite advances in invasion ecology, scientists and managers are disconnected and research is rarely implemented. I conclude by proposing seven solutions to facilitate the integration of science into management. / Forestry, Faculty of / Graduate

This study elucidates the underlying relationships for the distribution of oak landcover on bedrock and soil orders in two counties in Texas and one in Oklahoma. ESRI's ArcGis and ArcMap was used to create surface maps for Denton and Coke Counties, Texas and Choctaw County, Oklahoma. Attribute tables generated in GIS were exported into a spreadsheet software program and frequency tables were created for every formation and soil order in the tri-county research area. The results were both a visual and numeric distribution of oaks in the transition area between the eastern hardwood forests and the Great Plains. Oak distributions are changing on this transition area of the South Central Plains. The sandy Woodbine and Antlers formations traditionally associated with the largest oak distribution are carrying oak coverage of approximately 31-32% in Choctaw and Denton Counties. The calcareous Blackland and Grand Prairies are traditionally associated with treeless grasslands, but are now carrying oak and other tree landcover up to 18.9%. Human intervention, including the establishment of artificial, political and social boundaries, urbanization, farming and fire control have altered the natural distribution of oaks and other landcover of this unique georegion.

An integrated flow and transport model using MIKE SHE/MIKE 11 software was developed to predict the flow and transport of mercury, Hg(II), under varying environmental conditions. The model analyzed the impact of remediation scenarios within the East Fork Poplar Creek watershed of the Oak Ridge Reservation with respect to downstream concentration of mercury. The numerical simulations included the entire hydrological cycle: flow in rivers, overland flow, groundwater flow in the saturated and unsaturated zones, and evapotranspiration and precipitation time series. Stochastic parameters and hydrologic conditions over a five year period of historical hydrological data were used to analyze the hydrological cycle and to determine the prevailing mercury transport mechanism within the watershed. Simulations of remediation scenarios revealed that reduction of the highly contaminated point sources, rather than general remediation of the contaminant plume, has a more direct impact on downstream mercury concentrations.

A seasonal survey of the distribution of terrestrial tardigrades on Dugger Mountain, Alabama, was conducted during the time period from April 1997 through April 1998. Cryptogams from five trees (Quercus alba), three on north-facing slopes and two on south-facing slopes, were sampled seasonally at three stations (645 m, 410 m, 183 m) along an unnamed tributary of the South Fork of Terrapin Creek. Trees were chosen based on their location outside the riparian zone. Tardigrades were extracted from the samples, mounted individually in Hoyer's medium, and identified to species with phase microscopy. Seasonal and altitudinal variations in the distribution of the populations on the north- and south-facing slopes were determined. Present on Dugger Mountain were tardigrades belonging to 12 species (Macrobiotus cf. areolatus/tonollii, Macrobiotus cf. echinogenitus, Macrobiotus islandicus, Macrobiotus richtersi, Minibiotus intermedius, Milnesium tardigradum, Diphascon pingue, Hypsibius pallidus, Echiniscus cf. arctomys. Echiniscus virginicus, Pseudechiniscus ramazzottii, and Pseudechiniscus suillus). Due to the small numbers of individuals of each species, the total numbers of tardigrades of all species were pooled. There were no significant differences in the mean number of species or the mean number of all tardigrades per sample at each station (altitude). However, seasonal differences in both abundance and number of species were detected in pooled samples due to the high numbers collected in spring 1997.

I assessed avian communities of Gam bel oak (Quercus gambelii) woodland and surrounding habitats at Camp W. G. Williams State Military Reservation , Utah, during summer of 1993-1998. I used point counts and incidental observations to compile an avian checklist. I observed 100 species, accounting for one third of all birds known from Utah. Overlap in species composition among habitats was considerable, yet each habitat supported a distinct complement of common species. I compared bird species composition, abundance, richness, and diversity before and after fire in burned and unburned Gam bel oak woodland using point counts. I also investigated how similarity of the Gam bel oak avian community to surrounding communities changed after fire. Post-fire changes in individual species abundances reflected a shift from a woodland to a grassland/shrubland community. However, this shift occurred through elimination rather than addition of species, i.e., the post-fire Gambel oak avifauna was a subset of the pre- fire avifauna. Species richness and diversity on burned plots decreased significantly after fi re; unburned plots experienced significant increases in richness and diversity. I also used point counts to evaluate recovery of the Gam bel oak avian community by comparing species composition, abundance, richness, and diversity in different-age burned and unburned Gambel oak woodland. Total abundance, richness, diversity, and similarity to the unburned community increased with post-fire age. I observed significant differences in the abundance of 10 species. Fire did not result in sequential invasion and replacement of bird species assemblages; rather, species found in burned plots were a subset of the avifauna in unburned plots. Return of individual species was related to recovery of preferred nesting and foraging substrates. Over 25% of species found in unburned plots were still absent 11 years post-fire. I conclude that fire had pronounced effects on avian community composition and structure in this habitat. The contention that almost all bird species associated with Gambel oak woodlands are tolerant to fire is not substantiated by the results of this study. Due to the lack of spatial replication in this study, a comparison of avian response to fire in several sites across Gambel oak range would be desirable.

Fresh-harvested Gambel oak (Quercus gambelii) browse was mixed with chopped alfalfa hay to formulate six diets , varying in oak content at two phenological stages. Diets included juvenile oak (65 ,80,95%), mature oak (40,80\), and an alfalfa control . Diets we re evaluated for goats using a series of total-collection dige st ion balance trials . Dry matter intake was highest for animal s on mature oak diets, and lowest on diets containing a high percentage of juvenile oak, possibly due to differences in diet dry matter content . Apparent digestibility of dry matter and cell wall components was lowest for mature oak diets, and highest for diets high in juvenile oak. Nitrogen and energy balances were positive in all cases , and all diets provided nitrogen and energy in excess of rnaintenance requirements. This was reflected by weight gains for all animal s in every trial. Fecal and urinary nitrogen losses did not appear to be related to tannin content of the diets, because high-percentage juvenile oak diets resulted in reduced nitrogen outputs , presumably due to reduced nitrogen intakes for these diets. In comparison with previous data using pelleted formulations, the fresh-fed material was consistently higher in digestibility of the various fractions, and associated with lower dry matter intakes.

No description available.

In this research, the fire effects on structural and compositional change, and advance regeneration of oak forests in the Ozarks of Missouri were investigated by combining the statistic methods of MANONA, survival analysis, CART analysis, and logistic analysis. Results indicated that fire treatments significantly reduced the midsotry and understory basal area and stem density. However, fire effects on overstory tree survival differentiated among size classes. A new morphological variable, ratio of the total height to the square of basal diameter, was found to be statistically significantly related to the tree mortality rate for most of the species. The developed logistic regression models for selected species using the morphological variable well simulated the impact of initial stem size of advance regeneration on mortality for most of the species. The resultant logistic regression models could be a potential tool to compare and quantify species response to fires on a comparable basis.

Acorns of red oaks (Quercus spp; Subgenus Erythrobalanus) are important forage for wildlife and seed for oak regeneration. I estimated production of viable acorns by red oaks in 5 forests in the Mississippi Alluvial Valley (MAV) and 2 greentree reservoirs (GTRs) in Mississippi. Mean acorn production in the MAV was 439 kg(dry)/ha of red oak crown (CV = 29%) during autumn-winter 2009-2010 and 794 kg/ha (CV = 19%) in GTRs during autumn-winters 2008-2010. I recommend researchers sample acorn production in the MAV for ≥5 years to improve precision of estimates (i.e., CV ≤ 15%). I estimated mass and gross energy (GE) of viable red oak acorns after 90 days in unflooded and flooded hardwood bottomlands in Mississippi. Within species, mass loss of acorns was <8.4% and variation in GE ≤0.08 kcal(dry)/g. Winter decomposition of intact viable red oak acorns would have minimal effect on wildlife carrying capacity of hardwood bottomlands.

Cross-laminated boards is a technique of joining together lamellas of wood to create more dimensionally stable boards. Ballingslöv uses cross-laminated boards in their production and sometimes they observer cupping in the boards that may halt production. To find out why this might be occurring a study was performed where cross-laminated oakboards (Quercus Robur. L) were placed in three different climates for twelve days. During these twelve days cupping, weight, and thickness was measured every twenty-four hours. The results showed that the temperature and relative humidity of the surrounding environment affected how much and how fast cupping and weight change occurred in the boards.  It was concluded that the study needs to be replicated on a larger scale to increase the certainty of the results.