The global community is struggling with mitigating the effects of widespread habitat loss and degradation; the effects of which are being further magnified in the face of global climate change. Quality natural habitat is becoming increasingly limited and atmospheric carbon levels continue to rise. Therefore, land managers responsible for multiuse management are often faced with the dilemma of managing ecosystems for biodiversity, as well as optimizing ecosystem services such as carbon storage and sequestration. However, some management techniques used to meet these objectives may yield conflicting results, specifically, the management tool of prescribed fire. Fire is crucial in maintaining species composition and structure in many ecosystems, but also results in high carbon emissions. Thus, it is important for land mangers to achieve the most efficient prescribed fire management regime to both preserve plant and animal communities, and optimize carbon storage. A former ranchland at the Disney Wilderness Preserve, Central Florida, USA is being restored to native ecosystems and managed to preserve biodiversity and increase carbon storage. This study quantified the carbon stocks within the aboveground biomass, litter, and top 90 cm of soil in five ecosystems at the Disney Wilderness Preserve, all of which are managed with prescribed fire every two to three years. These carbon stocks were compared in ecosystems in different stages of restoration: bahia grass pasture, pasture in restoration for longleaf pine flatwoods, and restored longleaf pine flatwoods. The carbon stocks were also compared among three restored flatwoods communities: longleaf pine flatwoods, slash pine flatwoods, and scrubby flatwoods. To determine the effects of the current prescribed fire management, carbon stocks were quantified and compared in recently burned areas (burned 4 months prior) and areas burned two to three years prior, in all ecosystems. Soil carbon properties were assessed using ¹³C isotope analysis. Aboveground biomass and litter carbon stocks were found to increase with higher stage of restoration, and were significantly less in areas with recent fire management. The results of this study did not provide evidence that soil carbon stock was significantly different in different stages of restoration or at different times since fire, but soil carbon stock was found to be significantly different among the flatwoods communities. In un-restored pasture and pasture in restoration sites, the soil was found to be increasingly depleted in ¹³C with increasing soil depth. This pattern indicated that carbon in the upper, more labile soil carbon pool had been derived from current C4 pasture or native grasses, while carbon in the deeper, more stable carbon pool is a legacy of the historical C3 forest vegetation that existed prior to conversion to pasture. Additionally, a pattern of less depletion in ¹³C with increasing time since deforestation was noted, indicating an increasing loss of historic forest carbon with increasing pasture age. As the pastures in restoration for longleaf pine flatwoods mature, the isotopic composition of the soil profile in the restored longleaf pine flatwoods may serve as a reference value for the soil profiles of these sites. Overall, the mean carbon stock in the aboveground biomass, litter and top 90 cm of soil in the un-restored pasture was ~13.3 kg C/m², the carbon stock in the pasture in restoration was ~12.7 kg C/m², the longleaf pine flatwoods had the highest carbon stock at ~17.7 kg C/m², the scrubby flatwoods had the smallest carbon stock at ~7.7 kg C/m², and the slash pine flatwoods had a carbon stock of ~15.8 kg C/m².

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Old-growth forests provide important habitat for wildlife, support the maintenance of biodiversity and serve as control areas for scientific research. Expanding current old-growth stand area by utilizing neighboring younger, managed stands allows private landowners to meet management needs and enables government agencies and private conservation organizations to meet old-growth forest objectives. Seven old-growth upland oak stands and seven adjacent younger, managed stands of the same site and stand type were measured in the Ridge and Valley, Blue Ridge, and Piedmont provinces of Virginia and Pennsylvania in an effort to characterize species composition, diameter distribution and canopy structure. A computer-based ecosystem/gap model (JABOWA-3) was modified and used to simulate silvicultural manipulations in the younger stands that would reproduce older forest characteristics. Various silvicultural techniques were used to convert the primarily even-aged younger stands into uneven-aged stands and then into old-growth. These manipulations included single-tree selection, herbicide application, culling larger diameter stems and planting seedlings where required. Individual trees within each of the younger, managed stands were removed at various time intervals and these simulated stands were then projected to a point in time in which the stand approximated the diameter distribution and composition of its paired old-growth stand. Several projections were made in each of the younger stands to meet this objective. Once a satisfactory projection was made for conversion of a younger stand to old-growth, a success rate was determined to gauge how close the simulated stand approximated the diameter distribution and composition of its old-growth counterpart. From this information, biologically feasible and environmentally sound management plans were created to carry out the silvicultural manipulations required by the model for each of the sites. / Master of Science

Survival and growth of planted trees are common indices used to evaluate success of wetland restoration efforts used to compensate for wetland losses. Restoration efforts on marginal agricultural lands typically result in less than satisfactory survival and growth of desired tree species. This study evaluated seed source ecotype, greenhouse preconditioning and combinations of five mechanical site preparation techniques (mound, bed, rip, disk, pit), four levels of planting stock (gallon, tubeling, bare root, and direct seed), and three planting aids (mat, tube, none) on the survival and growth of American sycamore (Platanus occidentalis L.) and willow oak (Quercus phellos L.) planted on an old field riparian area in the Virginia Piedmont. American sycamore seedlings subjected to greenhouse flood preconditioning had 25% greater height and willow oak seedlings grown under normal greenhouse conditions had 18% greater diameter, but these greenhouse adaptations did not confer greater survivability or growth after field planting. American sycamore seeds sourced from dry ecotypes were 14% taller than wet ecotype seeds, and willow oak acorns sourced from wet ecotypes were 11% taller than dry ecotype acorns, indicating that parental ecotype may influence survivability and growth. The combination of mounding site preparation and gallon planting stock increased mean survival to 100% and aboveground dry biomass (5.44 Mg/ha/yr) in American sycamore. Willow oak had 45% greater woody stem volume with mounding site preparation 80% greater woody stem volume with gallon and bare root planting stock. Tubeling planting stock provided significant benefit relative to the low planting stock cost for American sycamore, while bare root seedlings were shown to be an effective planting stock for willow oak. The use of appropriate ecotype seed sources, use of mounding mechanical site preparation techniques and planting of species appropriate planting stock increased survival and growth of common early and mid-successional Piedmont tree species on marginal agricultural lands. Treatments that appear to be economically viable for restoration and mitigation efforts could potentially offer other economic incentives such as short rotation woody crops and timber value, which might induce additional private landowners to attempt restoration efforts in marginal old field riparian areas. / Doctor of Philosophy / In order to offset the loss of wetlands due to development, strategies are needed to create wetlands in areas along streams that are unfarmed. Survival and growth of planted trees are commonly used to evaluate the success of these new wetland areas. The goal of this research is to provide alternative methods to increase survival and growth of two common trees planted in the Piedmont of Virginia. The results show that creating mounds of soil before planting trees and planting larger trees will increase tree survival and growth in these wetland areas. Landowners and land managers can use these methods to increase the value of unfarmed land along streams while also increasing water quality and providing habitat animals that use the streams and wetlands.

Large-scale carbon-free energy generation projects such as utility-scale solar energy (USSE) arrays help mitigate the energy sector’s contribution to climate change and are rapidly expanding throughout the U.S. However, the expansion of USSE sites is associated with immediate and longer-term ecological impacts, many of which have yet to be assessed. Quantifying the ecological impacts of USSE arrays will help to identify synergies and trade-offs between energy generation and terrestrial conservation goals. The overall goal of this research is to characterize the ecological impacts of USSE sites located on fallowed farmlands in San Luis Obispo County, California in a seasonally explicit manner. Fallowed agricultural landscapes and rangelands represent a particularly promising area for the deployment of solar arrays because these systems typically are significantly altered from their native conditions; therefore, array placement may not have significant further deleterious ecological impacts and may also provide the potential to recover ecologically with shifts in management practices. We studied how arrays impact a suite of ecological properties, focusing on two USSE arrays in California’s Coast Range Valley: Topaz Solar Farm (developed 2014)and Goldtree Solar Farm (developed 2018). Topaz, which is situated on previously disturbed agricultural land in Carrizo Plain, was seeded with a native seed mix prior to installation and uses rotational grazing to control vegetation growth. The climate is more arid at Topaz than at Goldtree, which is located approximately 14 miles from Morro Bay. Goldtree is situated on sheep pastureland and is also managed with a rotational grazing regime, though with a higher intensity than at Topaz. Solar farms created distinct patterns of heterogeneity, which then affected plant community changes and soil nutrient cycling. Partial shading in areas adjacent to panels increased species richness with more native species and higher functional diversity, especially in drought conditions. Full shading in areas directly under plots increased plant moisture content and plant nitrogen content during drought conditions. This may be beneficial in supplying plants with greater water availability and nutrients, especially during drought years. In solar array footprints, ecosystem respiration (plant and soil CO2 flux) was reduced, suggesting that shading on solar farms can improve carbon sequestration on disturbed agricultural land if organic matter inputs outpace carbon loss in this novel ecosystem. Thus, our study demonstrated that solar farms offer the potential for improvement of ecosystem services, if placed on previously disturbed landscapes such as fallowed farmland and combined with other conservation management practices.

This study created an ecological spatial model, using a geographic information system, to visualize the influence of hydrochory on restoration of the three dominant wetland communities of broadleaf marsh, wetland shrub, and wet prairie across the floodplain of the Kissimmee River. Primary parameters incorporated into the model included floodplain hydrology, seed characteristics of buoyancy and dispersal rates, and species flood tolerance. S²rensen's similarity index, comparing spatial agreement among model output and observed community data, resulted in values of BLM-BB = 0.10, BLM = 0.07, WS = 0.21, and WP = 0.36. The significant discrepancies between modeled and observed community spatial coverage indicated a need for incorporation of more stochastic variables of climatic disturbances, nutrient availability, and soil characteristics. More research on species flood tolerance across smaller spatial scales is also needed, and base data incorporated into the model should also be reliable and consistent if accuracy is to be achieved. / by Stevee Kennard. / Thesis (M.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Yuen Siu-man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 158-180). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.vi / Table of Contents --- p.ix / List of Tablcs --- p.xvi / List of Figures --- p.xix / List of Plates --- p.xx / List of Appendices --- p.xxi / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- lntroduction --- p.1 / Chapter 1.2 --- The Problem --- p.5 / Chapter 1.2.1 --- Towngas pipeline --- p.5 / Chapter 1.2.2 --- Environmental impact assessment (EIA) --- p.6 / Chapter 1.2.3 --- Landscape restoration --- p.11 / Chapter 1.3 --- Conceptual Framework --- p.12 / Chapter 1.3.1 --- Ecosystem disturbance and soil impacts of pipeline construction --- p.12 / Chapter 1.3.2 --- Scope and baseline --- p.14 / Chapter 1.3.3 --- Mitigation and restoration guidelines --- p.16 / Chapter 1.4 --- Objectives of the Study --- p.18 / Chapter 1.5 --- Significance of the Study --- p.21 / Chapter 1.6 --- Scope of the Study --- p.22 / Chapter 1.7 --- Terminology in the Thesis --- p.23 / Chapter 1.8 --- Organization of the Thesis --- p.26 / Chapter Chapter 2 --- Literature Review / Chapter 2.1 --- Ecosystem Disturbance and Impacts of Pipeline Construction --- p.27 / Chapter 2.2 --- Soil as an Important Natural Resource --- p.29 / Chapter 2.3 --- Environmental Impact Assessment (EIA) --- p.31 / Chapter 2.3.1 --- Theory and practice of EIA --- p.31 / Chapter 2.3.2 --- EIA in Hong Kong --- p.33 / Chapter 2.3.3 --- Soil assessment in EIA --- p.34 / Chapter 2.3.4 --- Ecological impact assessment in EIA --- p.35 / Chapter 2.3.5 --- Mitigation --- p.36 / Chapter 2.3.6 --- Significance of impacts --- p.38 / Chapter 2.3.7 --- Weaknesses of EIA --- p.39 / Chapter 2.3.8 --- "Post-project analysis, monitoring and audits" --- p.41 / Chapter Chapter 3 --- Study Area and Methodology / Chapter 3.1 --- Introduction --- p.44 / Chapter 3.2 --- Climate --- p.46 / Chapter 3.3 --- Geology and Soils --- p.46 / Chapter 3.4 --- Study Plots --- p.48 / Chapter 3.5 --- Methodology --- p.56 / Chapter 3.5.1 --- Experimental design --- p.56 / Chapter 3.5.2 --- Fieldwork --- p.57 / Chapter 3.5.3 --- Laboratory analysis --- p.58 / Chapter 3.5.4 --- Date processing and statistical analysis --- p.61 / Chapter 3.5.5 --- EIA report review --- p.62 / Chapter Chapter 4 --- Soil Baseline / Chapter 4.1 --- Introduction --- p.63 / Chapter 4.2 --- Results --- p.64 / Chapter 4.2.1 --- Texture --- p.64 / Chapter 4.2.2 --- Bulk density --- p.65 / Chapter 4.2.3 --- Soil acidity --- p.65 / Chapter 4.2.4 --- Exchangeable acidity and aluminum --- p.66 / Chapter 4.2.5 --- Soil organic matter (SOM) --- p.67 / Chapter 4.2.6 --- Total and mineral nitrogen --- p.67 / Chapter 4.2.7 --- Total and available phosphorus --- p.69 / Chapter 4.2.8 --- Exchangeable cations --- p.70 / Chapter 4.2.9 --- "Effective cation exchange capacity (ECEC), base saturation (BS) and aluminum saturation" --- p.72 / Chapter 4.2.10 --- C/N ratio --- p.73 / Chapter 4.3 --- Discussion --- p.74 / Chapter 4.3.1 --- Acidity problem --- p.74 / Chapter 4.3.2 --- Soil texture and bulk density --- p.75 / Chapter 4.3.3 --- Soil organic matter and nitrogen --- p.76 / Chapter 4.3.4 --- Soil phosphorus --- p.78 / Chapter 4.3.5 --- "Exchangeable cations, ECEC. BS and aluminum saturation" --- p.78 / Chapter 4.3.6 --- Implications on landscape restoration --- p.80 / Chapter 4.4 --- Conclusion --- p.82 / Chapter Chapter 5 --- Impacts of Pipeline Construction on Soils / Chapter 5.1 --- Introduction --- p.84 / Chapter 5.2 --- Results --- p.85 / Chapter 5.2.1 --- "Soil acidity, exchangeable hydrogen and aluminum" --- p.86 / Chapter 5.2.2 --- Soil texture and bulk density --- p.88 / Chapter 5.2.3 --- Soil organic matter --- p.90 / Chapter 5.2.4 --- Soil TKN --- p.90 / Chapter 5.2.5 --- Phosphorus --- p.91 / Chapter 5.2.6 --- Soil exchangeable cations --- p.94 / Chapter 5.2.7 --- "ECEC, BS and aluminum saturation" --- p.96 / Chapter 5.3 --- Discussion --- p.99 / Chapter 5.3.1 --- Nature of the soil impacts --- p.99 / Chapter 5.3.2 --- Causes of soil impact --- p.101 / Chapter 5.3.3 --- Spatial difference of soil impacts --- p.108 / Chapter 5.3.4 --- Significance of the impacts --- p.111 / Chapter 5.3.5 --- Mitigation measures --- p.117 / Chapter 5.4 --- Conclusion --- p.120 / Chapter Chapter 6 --- Improvement of EIA on Soil Management / Chapter 6.1 --- Introduction --- p.122 / Chapter 6.2 --- Evaluation of Information Provided by the EIA --- p.124 / Chapter 6.2.1 --- Need of more detailed soil baseline --- p.124 / Chapter 6.2.2 --- Inadequate soil impact prediction --- p.126 / Chapter 6.2.3 --- Need of site-specific soil mitigation --- p.128 / Chapter 6.2.4 --- Soil management in EIA --- p.130 / Chapter 6.3 --- Soil Impact Assessment (SIA) --- p.136 / Chapter 6.3.1 --- Soil baseline --- p.138 / Chapter 6.3.2 --- Impact prediction and significance --- p.140 / Chapter 6.3.3 --- Mitigation in SIA --- p.142 / Chapter 6.3.4 --- Monitoring in SIA --- p.143 / Chapter 6.3.5 --- Post-project evaluation in SIA --- p.144 / Chapter 6.3.6 --- Application of SIA --- p.145 / Chapter 6.4 --- Conclusion --- p.146 / Chapter Chapter 7 --- Conclusion / Chapter 7.1 --- Summary of Findings --- p.147 / Chapter 7.1.1 --- Undisturbed soil conditions --- p.147 / Chapter 7.1.2 --- Soil impacts and resultant soil properties --- p.149 / Chapter 7.1.3 --- Evaluation of the EIA Report --- p.151 / Chapter 7.2 --- Implications --- p.152 / Chapter 7.2.1 --- Challenge to Aber's disturbance level theory --- p.152 / Chapter 7.2.2 --- Consolidation of impacts assessment in EIA --- p.153 / Chapter 7.2.3 --- Information for soil impact assessment --- p.154 / Chapter 7.3 --- Limitations of study --- p.154 / Chapter 7.4 --- Further Research --- p.156 / References --- p.158 / Appendices --- p.181