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In July of 1993 an underground coal mine owned and operated by Southern Ohio coal company (SOCCO) underwent emergency recovery operations due to flash flooding of the mine from an adjacent abandoned mine. During mine dewatering operations, approximately 132,650 liters per minute of acid mine water was released into the Parker Run tributary draining into Leading Creek. The 24.2-km section of Leading Creek was heavily impacted eradicating most aquatic organisms. An acutely toxic impact resulted from the discharge of high conductivity (~6000µmhos), low pH (2.5-3.1 pH units), high metal concentrations (iron and iron floc, manganese, copper, nickel, zinc and aluminum, mg/L) and high total suspended solids (TSS). Through the process of a Consent Decree, a proactive plan was developed for monitoring the recovery in Leading Creek and to develop an enhancement plan for the watershed. SOCCO set aside $1.9 million that has grown to $2.5 million to cover the costs of implementing specific enhancement measures in the watershed. The primary goal of the enhancement plan was to describe actions that could reasonably be taken to affect measurable ecological rehabilitation or enhancement of the Leading Creek stream system so it attains the highest Ohio EPA aquatic life use designation possible. The objectives of this research project were to identify specific ecosystem stressors affecting the habitat quality within the watershed preventing Leading Creek from attaining either the Warmwater Habitat (WWH) or the Excellent Warmwater Habitat (EWH) designation and to provide potential remediation techniques to address the identified stressors. Although natural processes have lead to partial recovery in Leading Creek from the impact of dewatering, reconnaissance has shown significant problems relating to toxicity and habitat degradation in the watershed. Seventeen tributaries and ten mainstem stations were chosen to receive monthly monitoring as point source discharges, including biological, chemical, toxicological, and hydrological sampling. Specific ecotoxicological parameters studied included water and sediment quality, algal colonization upon artificial substrates, benthic macroinvertebrate sampling (qualitatively and quantitatively), acute water column toxicity, sediment chronic toxicity and </i>in situ</i> clam toxicity. Evaluation of habitat impairment included habitat assessments, in-stream riparian surveys and land use analysis. Through the analysis of laboratory and field data, agriculture and Abandoned Mined Land (AML) were identified as the two main stressors in the watershed. Agricultural practices contributed chronic toxicity through habitat degradation identified from benthic macroinvertebrate data and sediment depth measurements. AML impacted several tributaries and the Leading Creek mainstem by degrading water quality through the introduction of acidic waters, high in conductivity and heavy metals. Acid Mine Drainage (AMD) from the AML areas was pinpointed through acute testing with <i>Ceriodaphnia dubia</i> and </i>in situ</i> testing with the Asian clam, </i>Corbicula fluminea</i>. Active mining effluents from the Meigs #2 and Meigs #31 mines influenced the Ogden Run and Parker Run tributaries with conductivity values ranging from 2000 to 6000 μmhos/cm, respectively. The influence of the active mine effluents was observed down the mainstem from LCS6 to LCS10 in the form of high conductivity (~1200 μmhos/cm) and increased pH values (~8.0). Development of the enhancement plan began with the ranking of the ten mainstem stations and 17 tributary stations based on prioritization of impact parameters using an Ecotoxicological Rating (ETR) developed specifically for the Leading Creek watershed. The ETR included biological, toxicological, chemical and physical data to integrate a complete description of the impacts affecting the Leading Creek watershed. The 23 parameters in the ETR for the mainstem stations were; sediment depth, acidic pH, quantitative Invertebrate Community Index (ICI) scores, conductivity, clam <i>in situ</i> survival and growth, </i>Daphnia magna</i> and <i>Chironomus tentans</i> sediment toxicity, stormwater acute toxicity, qualitative invertebrate richness and Ephemeroptera, Plecoptera and Trichoptera (EPT) abundance, percent AML area, concentrations of sodium, copper, zinc, iron, manganese, chloride, nitrate/nitrite, ammonia, TSS, plus Qualitative Habitat Evaluation Index (QHEI) and United States Environmental Protection Agency (US EPA) habitat scores. For the mainstem stations, low flow in the summer was substituted for quantitative ICI scores. The ETR provided a single numerical score of 200 points that allowed comparisons to be made between sites within Leading Creek and tributaries within the watershed. Stressors identified within the watershed and used in the ranking of sites included agricultural sedimentation, sedimentation from AML, poor water quality from AMD and multiple toxic inputs such as acute stormwater runoff. Remediation techniques and costs were described to address poor agricultural practices and designed to alleviate sedimentation within the mainstem. Remediation techniques for AMD were described but due to the enormous amount of AML within the Leading Creek watershed, costs and specific projects were deemed beyond the scope of this research project. / Ph. D.

A typology of urban vacant land was developed using Roanoke, Virginia, as the study area. Because of its industrial past, topography and climate, Roanoke provides a range of vacant land types typical of those in many areas of the Mid-Atlantic, Eastern and Midwestern United States. A comprehensive literature review, field measurements and observations analysis and aerial photo interpretation and ground-truthing methods were utilized to identify and catalog vacant parcels of land and the results were mapped using i-Tree Canopy to identify the following types of urban vacant land: post-industrial (3.34 km2), derelict (4.01 km2), unattended with vegetation (17.3 km2), natural (2.78 km2), and transportation-related (5.01 km2). Unattended with vegetation sites are important resources as the health biodiversity found in natural sites benefits urban populations and they represent the highest plantable space. The redesign of post-industrial sites builds a city's image and transportation-related sites can contribute a green infrastructure network of open spaces. This typological study has significant implications for policy development, and for planners and designers seeking the best use for vacant urban land. The analysis of Roanoke's urban forest revealed around 210,000 trees on vacant land, a tree cover of 30.6%. These trees store about 107,000 tons of carbon (worth $7.65 million) and remove about 2,300 tons of carbon ($164,000), and about 91 tons of air pollution ($916,000) every year, which is high relative to other land uses. Trees on vacant land are estimated to reduce annual residential energy costs by $211,000 for the city's 97,000 residents and their structural value is estimated at $169 million. The methodology applied to assess ecosystem services in this study can also be used to assess ecosystem services of vacant land in other urban contexts and improve urban forest policies, planning, and the management of vacant land. The study findings support the inclusion of trees on vacant land providing a new vision of vacant urban land as a valuable ecological resource by demonstrating how green infrastructure can be used to enhance ecosystem health and promote a better quality of life for city residents. / Ph. D.

As a response to rising wildfire hazard and forest structure and composition concerns, the National Fire and Fire Surrogate Study was established in 2000 to determine how fuel reduction and ecosystem restoration techniques might affect ecosystem properties and processes across the United States. Soil chemistry and the southern Appalachian Mountains were an ecosystem property and ecoregion of interest, respectively. Treatments utilized at this site included: prescribed fire alone (3 burns), mechanical cutting of understory shrubs and midstory trees alone (2 cuttings), and a combination of the two (2 installations). Soils were sampled in 2018 to determine potential treatment impacts for: O horizon and mineral soil (0-10 cm depth) carbon (C), nitrogen (N), carbon:nitrogen (C:N) and mineral soil calcium (Ca), magnesium (Mg), phosphorus (P), potassium (K), and pH. Results suggested slight, but statistically significant changes in O horizon C and N and mineral soil C, N, C:N, Ca, and P values from 2001-2018 differed statistically between the treatments. Soil responses differed significantly between the replications utilized in this study and also did not fully agree with results from previous sampling that occurred following the first implementation of these treatments. This research highlights the spatial and temporal nature of soil responses to management. When considered with previously reported vegetation and fuels results from this site, it appeared that prescribed burning with and without mechanical cutting presented the most promise to achieve ecosystem restoration and fuel reduction properties without altering forest soil chemistry. / Master of Science / Fire was historically present in the southern Appalachian Mountains from both natural and anthropogenic sources. A common natural cause resulted from lightning ignitions while some common anthropogenic sources resulted from Native American ignitions. Their fire-use goals included understory clearing, reduction of pests and diseases, hunting, and even warfare. These practices were adopted by early European settlers and were implemented regularly across the landscape through the late 19th century. In the early 20th century, however, fire exclusion policies were implemented across broad acreages of the continental United States. Over 80 years later, such policies led to forests that have been altered from their historic composition. Some of these alterations include changes to plant species composition. In portions of eastern United States forests, fire intolerant, shade tolerant species now exert a dominant influence beyond what would be expected in a frequently altered state. This process, referred to as mesophication, is a positive-feedback cycle that changes the composition of the forest floor, as well, as a result of the vegetative composition alterations. This cycle has led to substantial forest floor fuel accumulations comprised of vegetative litter and duff. Essentially, this policy shift and subsequent fuel alteration has potentially increased wildfire hazard when dry weather conditions and ignitions coalesce. In 2000, the National Fire and Fire Surrogate Study (FFSS) was designed and implemented to study ecosystem responses to fuel reduction treatments in 13 locations across the United States. One of these locations was the southern Appalachian Mountains near Hendersonville, North Carolina. For this particular study, soil chemistry was the observed ecosystem trait. The treatments included untreated control, prescribed fire, mechanical cutting of vegetation, and a combination of prescribed fire and cutting. From 2001-2018, 4 prescribed burns, 2 cutting treatments, and 2 combination treatments have been implemented. Prior to the first treatments in 2001, soils were sampled to determine pre-treatment soil chemistry. In 2018, soils were re-sampled to determine the potential long-term impacts of repeated implementations of these management techniques on forest soil chemistry. Overall, the results suggested that forest soil chemistry was altered in ways that do not appear biologically significant and may in fact fail to alter soils in ways that might benefit and sustain long-term ecological restoration objectives. Continued treatment applications may be necessary to obtain more desirable conditions.

Residential non-industrial private forest (NIPF) owners within the Wildland/Urban interface are an increasingly important forest owner demographic. An increase in rural residential land use is fragmenting historically large contiguous forestlands. Consequently resource management has become decentralized. NIPF-landowners, as the new land managers, must now be capable of creating resilient forest ecosystems at the landscape scale. To overcome this issue landowners and resource managers at all levels of decision-making (including landowners) must come to understand how social structures such as psychology, organizations, institutions, and culture are linked to behavior and the physical world. Collaborative Interface Modeling (CIM) has been created in response to an information gap that exists between the social and natural sciences at the site scale. CIM reveals the causal linkages between land use decisions and their effects allowing landowners to more closely trace and investigate their management policies, behaviors, and feelings as well as the consequences of those behaviors. A demonstration of the CIM process with residential forest landowners is conducted to evaluate the process and detect possible implications of encroaching development on the Jefferson National Forest in Montgomery County, Virginia. A focus on fuel wood collection was established because it has been noted as a potential source of negative impact. Possible implications and improvements to the CIM process are also noted. / Master of Landscape Architecture

Oaks (Quercus spp.) are an important part of the forested landscape in the eastern United States. Although oak is increasing in standing volume, an oak regeneration bottleneck has occurred throughout its range in recent decades. Subsequently, as oak overstory is being harvested, rarely is oak recruited into the overstory to maintain the historic dominance of overstory oak. In the absence of fire and subsequent canopy closure, mesic species have proliferated, frequently forming a dense understory, inhibiting oak regeneration success. This study was developed to determine species dynamics between oak and oak competitors in response to silvicultural treatments in the southern Appalachian Mountains of North Carolina. The treatments were: a shelterwood treatment (25-30% basal area reduction through mid-story removal with herbicides), a prescribed fire treatment (two late dormant season fires occurred over a 9-year period), a shelterwood and burn treatment (prescribed fire 3-5 years following 30-40% basal area removal), and an unmanaged control. To determine treatment impacts on the regeneration layer, importance value and stems ha-1 were calculated at the species group and individual species level 0- and 9- years post initial treatment. A principal component analysis and an analysis of basal area by treatment 0- and 9-years post-treatment were used to determine the influence of site-specific characteristics on regeneration layer response. The greatest relative increases in importance values were 1401% and 2995% for the red oak group and yellow-poplar (Liriodendron tulipifera), respectively, in the shelterwood and burn (SWB). Change in all species groups were predominantly influenced by the smallest size-class (<0.6 m tall), with the exception of northern red oak (Q. rubra) and yellow-poplar in the SWB. The SWB significantly reduced importance values of all shade tolerant species groups and was the only treatment to decrease red maple (Acer rubrum) importance value and density over the study years. The prescribed fire (RXF) treatment increased red oak group importance value, while simultaneously decreasing yellow-poplar importance value and increasing red maple importance value. Changes in the red oak group in the SWB and the RXF were driven by northern red oak and scarlet oak (Q. coccinea), respectively. Treatments do not appear to change the competitive status of the white oak group. Elevation was closely associated with the red oak group. Yellow-poplar importance value increases, white oak group importance value increases, and site index were closely associated. Decreases in basal area were greatest in the SWB, and the SWB was the only treatment to significantly decrease overstory basal area. The RXF and SWB treatments improved the competitive status of only some oak species, but modifications to these treatments may result in better control of yellow-poplar and red maple competition, further improving oak's competitive status. Site specific factors such as elevation and site index may have impacted the regeneration layer response to treatments. / Master of Science / Oak-hickory (Quercus and Carya spp.) and oak-pine (Quercus and Pinus spp.) forest types occupy approximately 57 million and 11 million hectares of forestland in the eastern United States, respectively. Oaks are considered ecological and economic keystone species throughout the eastern U.S and maintenance of this genus in eastern U.S. forests has been a primary regional focus for decades. Historic disturbance regimes are estimated to have been much different than they are today. Fire was a common disturbance mechanism prior to fire suppression in the early 20th century. Frequent fires maintained much of the oak component historically. In the absence of fire, the species found in the understories of mature oak stands are commonly mesophytic species, such as yellow-poplar (Liriodendron tulipifera L.) and red maple (Acer rubrum L.). Over the last several decades, research has been conducted to investigate the impacts of treatments targeting the promotion of oak regeneration, but results have been varied and valuable long-term studies are rare. To determine the effects of treatments on the regeneration dynamics of oak and its competitors, four treatments were compared in the southern Appalachian Mountains. Treatments included a control, shelterwood harvest (SW), prescribed fire (RXF), and a shelterwood and burn (SWB). Stand structure and composition were monitored over a 9-year period post-treatment. Overall, results indicate the shelterwood and burn treatment has the greatest potential to improve the competitiveness of the red oak group in the regeneration layer, but yellow-poplar competition in the shelterwood and burn will need be addressed, considering its large increases in this treatment. Although increases in the red oak group were not as great as increases in the RXF treatment compared with the SWB, fire does show promise as a method to increase oak regeneration success. Changes in red oak group importance value varied with elevation, emphasizing results of treatments can be affected by site characteristics. Treatments were not successful at enhancing the competitive status of white oak (Quercus alba L.). Silvicultural treatments can be used to improve the competitive status of oak on sites in the southern Appalachian Mountains, but close monitoring of species dynamics throughout the rotation are needed to ensure long-term oak success.

The city functions as an Urban Ecosystem. As buildings are primary components of this system, each structure must appropriate its environment for the Urban Ecosystem to thrive. Additionally, each building acts as an individual ecosystem. Each building consumes energy, produces waste, and serves as an environment for life to flourish. This project investigates the study of architecture based on principles of ecology. The building holds a market, culinary school, and restaurants; receiving,transforming, and distributing sustenance to the city's inhabitants while supporting the greater metropolitan area farmers. The building exhibits the ubiquity of nature in the city and helps to revitalize an unhealthy part of Washington, DC's Urban Ecosystem. / Master of Architecture

Arsenic is a naturally occurring element, which is toxic to aquatic biota especially in disturbed areas where it may be found at high concentrations. A headwater stream adjacent to an 85 year-old abandoned arsenic mine was investigated to determine the influence of arsenic on stream biota and processes using an upstream (reference) and downstream (mine-influenced) comparative approach. Arsenic concentration was measured monthly at 10 sites along the stream length. Benthic macroinvertebrate surveys were conducted in both reaches five times throughout the course of a year. Leaf breakdown assays were conducted in reference and mine-influenced reaches. Leaf biofilm respiration was recorded during leaf breakdown assays and also with experimental arsenic additions to reference reach leaf biofilms. At the field site, arsenic concentrations varied from below detection limit (<2.5µg/L) to more than 12 mg/L. Macroinvertebrate density was greatly reduced down-gradient of the mine with 154 individuals/m2, while upstream there were 7869 individuals/m2. Leaf biofilm respiration rates were comparable to others found in the literature and not significantly different between reference and mine-influenced reaches. Further, experimental additions of arsenic did not alter biofilm respiration under laboratory conditions. However, shredder abundance on leaf packs was eight to twenty times greater upstream than the mine-influenced reach. Leaf breakdown rate varied two to three fold among sites distributed above and below the mine and were significantly lower in reaches of elevated arsenic concentration. Together, these data suggest that the mining operations on this headwater stream have altered organic matter processing primarily by decreasing invertebrate densities and limiting shredder abundance. / Master of Science

Rivers are amongst the most dynamic ecosystems on earth. River ecosystems are highly disturbed environments, where riparian vegetation, water and sediments, are interconnected by positive and negative feedbacks, driven by a set of interactions. In the last two decades, it has been widely recognized that these eco-morphodynamic feedbacks play a crucial role in governing the equilibrium and dynamics of river ecosystem. However, the incomplete understanding and quantification of these feedbacks limit the comprehension of river behavior and the development of efficient predictive models. Thus, in this research, fundamental intrinsic feedbacks between riparian vegetation and hydro-morphodynamic disturbance are modeled, where the disturbance is generated bymthe vegetation itself. The aim is to investigate how these intrinsic feedbacks govern themequilibrium and dynamics of a simplified river ecosystem.mTo this end, numerical simulations were conducted using both a 0D model (non-spatial)mand a 1D model (spatial) coupling hydro-morphodynamics with vegetation dynamics. The case study is a straight channel where vegetation can grow only in the central patch, while upstream and downstream there are bare soil regions. The system is perturbed periodically by a succession of floods of constant amplitude. Vegetation growth occurs in between of two consecutive floods, during low flood periods. Vegetation consists of two components, the above-ground biomass (canopy) and below-ground biomass (root depth). In both models, the canopy increases the roughness, reducing flow velocity. Variations in the flow field and the reduction of bottom shear stress modify sediment transport, leading to a greater imbalance between the vegetated and bare areas and thus, inducing erosion. Erosion increases the probability of vegetation uprooting, and when scour reaches root depth, uprooting occurs. The overall feedback loop is negative: higher vegetation biomass causes greater sediment flux imbalance and more erosion, ultimately resulting in less vegetation. However, root growth may inhibit the negative feedback loop, promoting positive feedbacks. Indeed, this interplay between hydro-morphodynamic disturbance (erosion) and the vegetation resistance (root depth), governs the predominance of either a positive or a negative feedback overall balance. Model results demonstrate that when the positive feedback overall balance prevails, the system always reaches a stable configuration. Furthermore, the system can exhibit hysteresis, meaning that, depending on the initial condition, it can achieve a stable configuration in two alternative states, the fully vegetated condition or bare soil. In the presence of the vegetated patch, the system can also exhibit a more complex multi-stable behavior, with infinite equilibria between the two alternative states. This also implies that spatial interactions smooth out critical transitions and tipping points, by facilitating smoother shifts that occur gradually through multiple smaller intermediate steps. Indeed, the resilience of the system, which is the ability of the system to still maintain its fundamental structure and functions after being subject to the ecological disturbance, increases due to spatial interactions. In contrast, when the negative feedback overall balance prevails, the system never reaches a steady state but exhibits dynamic oscillations. The oscillations can be either (i) periodic or (ii) aperiodic, strongly dependent on initial conditions, and with a positive Maximum Lyapunov Exponent, indicating chaotic behavior. The study also reveals that the route to chaos is a period-doubling bifurcation, and the calculation of time scale of predictability shows that the system is predictable only for a few growth-flood cycles. These results suggest that altering the ratio between hydro-morphodynamic disturbance and vegetation resistance, such as through anthropogenic pressure and climate change, may shift the system from a positive to a negative feedback overall balance. This shift could lead from a stable state to periodic oscillations or unpredictable chaotic behavior, limiting long-term predictions of river trajectories. Additionally, understanding how positive and negative eco-morphodynamic feedbacks govern river dynamics can contribute to develop efficient predictive models. Models are essential tools for implementing efficient river management and facilitate effective communication with stakeholders.

Ecosystem services are essential for human climate adaptation. As climate change is a direct driver of change for ecosystem service provisioning, it is of importance to care for our ecosystems to be able to cope with future challenges. Local governance has a central role in climate adaptation due to its responsibility in physical planning. To be able to plan for changes driven by climate change, a flexible, adaptive strategy is necessary. Ecosystem-based Adaptation, EbA, can provide this flexibility to an overall adaptation strategy. In this case study, the potential of EbA to help Nature-based Tourism, NbT, to adapt to a changing climate was spatially mapped to be a useful part of the basis for local physical planning. The mapping includes areas of biodiversity, water infrastructure and features that provide resilience to climate change. The results show that there are areas with potential for EbA that can address adverse effects of climate change for the NbT. These spatial mapped areas provide an instant overview of the key areas to consider when planning for climate adaptation. These mapped areas are also combined with a qualitative assessment of the potential for EbA. By providing decision-makers with information on where and how ecosystem services can assist local climate adaptation, decisions that support both the future of humanity and ecosystems are enabled. However, to reach enforcement of EbA, the knowledge has to be included in binding documents such as detail plans.