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In forested ecosystems, salamanders occupy important ecological roles as predator, prey and as potential regulators of ecological processes. The effects of forest management, particularly clearcut harvesting, on salamanders have been well documented; removal of overstory trees negatively affects abundances of salamanders. However, the length of time that salamander populations remain depressed following forest harvesting and factors limiting population recovery have been a source of controversy in the literature and are the goal of this dissertation. As part of the Southern Appalachian Silviculture and Biodiversity (SASAB) project (Chapter 1), a long-term replicated field experiment designed to evaluate a range of silvicultural treatments on biodiversity, I evaluated specific hypotheses related to salamander populations, their prey, and their habitat. First, I examined long-term trends in salamander abundances across a range of silvicultural treatments to determine whether negative effects of forest harvesting persisted for 13-years after harvest (Chapter 2) and to document the effects of multiple harvests on salamanders (Chapter 3). The relative abundances of terrestrial salamanders were quantified in six silvicultural treatments and an unharvested control and on six replicated field sites with night-time, area-constrained searches. Across 13-years of post-harvest data, terrestrial salamander abundances generally were lower in silvicultural treatments with some disturbance to the canopy (group selection harvest through silvicultural clearcut). Further, a comparison of demography of common species of salamanders suggested that differences in habitat quality existed between harvested and unharvested experimental units (EUs). A second harvest in the shelterwood plots to remove overwood had a cumulative negative effect on salamanders at one of two sites studied. Additionally, I conducted a sensitivity and elasticity analysis for eastern red-backed salamanders (Plethodon cinereus) and modeled population growth to evaluate the contribution of demographic parameters to population recovery. These analyses indicated that adult survival was the parameter with the greatest influence on the population growth rate and that >60 years would be required for recovery of salamander populations to preharvest levels even if habitat conditions were restored to preharvest conditions immediately. Next, I quantified the bioenergetics of salamanders across a disturbance gradient to evaluate whether changes to (1) invertebrate prey, (2) energy expenditure for basic maintenance costs, and or (3) an index to body condition could help explain observed changes to abundances or demography of salamanders from forest harvesting (Chapter 4). Although I did not detect a difference in abundances of invertebrates along the disturbance gradient, I determined that salamanders in recently disturbed forest stands expended approximately 33% more energy for basic maintenance costs in an active season and the body condition of salamanders was greater at one of two sites in disturbed EUs. Thus, the bioenergetics of terrestrial salamanders may have been affected by increasing temperatures from silvicultural disturbance and may cause salamanders to allocate less energy to reproduction or growth because of increased maintenance costs. In collaboration with Eric Sucre, Department of Forestry at Virginia Tech, I examined the effects of salamanders on invertebrates and ecosystem processes, specifically leaf litter decomposition. We constructed 12 in situ field mesocosms and I manipulated densities of red-backed salamanders into zero, low, and high density treatments. From June 2006-June 2008, I estimated invertebrate abundances, rates of leaf litter decomposition and food habits of salamanders across treatments. I found that invertebrate abundances were more affected by season than by the density of salamanders and that rates of leaf litter decomposition did not differ among salamander treatments. Salamanders were euryphagic and consumed more (by abundance and volume) herbivorous invertebrates than predators or detritivores. Finally, I modeled habitat relationships of terrestrial salamanders at two spatial scales on the SASAB study sites (Chapter 6). I quantified abundance of salamanders with area-constrained searches during warm rainy nights and measured forest characteristics related to foraging or refugia habitats or that described the overstory and understory of forest stands. At the scale of the 30 m2 transect and the 10 m2 sub-transect, abundance of salamanders was best described by models that incorporated descriptors of canopy cover and woody and herbaceous understory vegetation. Thus, terrestrial salamanders may have responded positively to forest stands with a mature overstory and structurally diverse understory for foraging habitat. Collectively, these data suggest that recovery of salamander populations after forest harvesting will take approximately 60 years, and that life history characteristics (low fecundity, late sexual maturity) and possibly changes to bioenergetics may contribute to the slow recovery. Further, silvicultural practices that retain some canopy trees through a rotation may have a more rapid return of salamander populations to preharvest levels and may encourage development of understory structure for salamander foraging. Although these data fill some gaps in knowledge of relationships between silviculture and terrestrial salamanders, many questions about long-term effects of disturbances on populations and habitats remain. My modeling of recovery of salamander populations depended on estimates of a survival from a congener, and I did not document whether forest harvesting decreases survival of terrestrial salamanders. Lastly, the influence of stochastic events on population dynamics particularly in disturbed stands was not examined in this dissertation. Therefore, future research on the SASAB study sites should continue to track abundances and demography across the disturbance gradient, acquire age-specific estimates of survival, determine whether salamanders exhibit density dependence, develop estimates of entire energy budgets, and use manipulative laboratory experiments to describe the role of plethodontid salamanders in ecosystem functions. / Ph. D.

Attempts by behavior scientists to test interventions designed to promote environmentally-responsible behavior (ERB) have been documented for decades. Numerous behavioral scientists have looked to community-based interventions to decrease environment-destructive behaviors, as well as to increase environmental-protective behaviors (Geller, 1995). Litter is one of the most obvious examples of environmental degradation. Litter, defined here as misplaced waste material (Geller, Winett, & Everett, 1982), is a form of environmental pollution that not only degrades the quality of the environment but also proves costly to taxpayers. A wide variety of ecological and monetary benefits result from a decrease in litter. The current research examined the effectiveness of positive vs. negative antecedent messages to reduce littering behavior. A methodology similar to that used by Geller, Witmer, and Orebaugh (1976), in which handbills containing weekly supermarket specials and special anti-litter message prompts were distributed at local community shopping centers, was used in the current research. In the first study, handbills with no anti-litter messages were distributed for a one-week period to determine percentage of handbills that were littered, and to serve as a baseline. The total percentage of handbills littered was 38.5. A second, web-based, study was conducted to determine the six specific (three positive or gain-framed, and three negative or loss-framed) anti-litter antecedent messages to be added to the handbills. In the third study, handbills with anti-litter messages were distributed for a two-week period. Upon addition of anti-litter prompts, results revealed 36.09% of distributed handbills were littered. Although no significant interactions were found, several significant main effects were found for store location, distribution period, and gender. The gender effect, indicating women littered at significantly higher rates than males, is notable. Survey research in the area of gender differences related to environmental concerns often has often shown modest differences between men and women, with women frequently displaying greater levels of environmental concern as compared to men. Based on behavioral observations (instead of self-report measures frequently used in previous research), the present research demonstrated significantly more women littering than men. Although slightly more handbills, in terms of total handbill numbers, containing positive antecedents were littered as compared to those containing negative antecedents (which might be interpreted as stronger impact of loss-framed messages), this difference was not statistically significant. Similarly, there were no statistically significant differences found among each of the six anti-litter messages. Comparisons of Study 1 (baseline) and Study 2 (prompting intervention) revealed significantly more littered handbills in the baseline condition as compared to the anti-litter message condition. These results indicate a beneficial anti-litter effect of the prompts added to handbills. Conclusions based on the findings of the three studies within the present research are discussed. Implications for policies, public campaigns, and follow-up research designs are noted. Suggestions for future research involving message prompts and ERBs are offered. / Ph. D.

Organoarsenic compounds and trace elements are added to poultry feed for disease control and improved productivity. These elements are excreted into poultry litter, which is land applied as fertilizer. This study utilized field and laboratory experiments to address the mobility of arsenic (As) and other litter-derived elements within the Broadkill River watershed, DE, a region of intense poultry production. For the first project, a litter application experiment was conducted at an instrumented field site in Sussex Co., DE. After establishing baseline geochemistry of soil water, ground water, and surface water at the site, poultry litter was then applied, followed by post litter application monitoring. Results showed low concentrations of As and other litter-derived elements in soil water; little impact was measured on ground or surface water. Mass balance calculations suggest that the majority of mass of leached elements was accounted for by uptake in underlying soils. The second project examined the impact of long-term litter application on chemical signatures of As, copper (Cu), zinc (Zn) and phosphorous (P) in stream sediments within the Broadkill River watershed. Sediment samples were collected from both upgradient and downgradient reaches within the watershed. Using GIS to overlay hydrology and land use, statistical relationships between As, Cu, Zn and P enrichment factors and land use were examined. Results did not show a relationship between these elements and agricultural land use, but did show a correlation between some of the elements and residential land use. The third project examined the influence of dissolved organic carbon (DOC) on the mobility of As, Cu, Zn and P using laboratory column experiments with soil from the field site. Two influent solutions were used: poultry litter leachate and a simulated solution of similar element concentrations, pH, and ionic strength but without DOC. Results showed that DOC enhanced the mobility of all four elements, but that even with DOC, 60-70% of the Zn, As and P mass was retained within the soil. Cu was fully mobilized by DOC. Patterns of breakthrough curves (BTCs) and mass calculations suggest that the behavior of these litter-derived elements in the column is controlled by both adsorption (including competitive) to soils and complexation with DOC. / Ph. D.

Litter decomposition is a poorly understood function of constructed and natural forested wetlands. This study compared rates of litter mass loss, changes in litter morphology, and associated macroinvertebrate populations in constructed and natural non-tidal wetlands. Two sets of wetlands (constructed vs. natural) were studied in eastern Virginia; a 9 year-old riparian set near Fort Lee, (FL), and a 2 year-old wet flat set in Charles City County, (CC). Mixed deciduous forest litter collected from the FL natural wetland decayed more rapidly in the created wetlands than the adjacent forested wetlands. Mixed emergent marsh litter collected from the FL created wetland exhibited a similar relationship, although marsh litter decomposed slower than forest litter. Litter area and weight loss followed a similar pattern, although area loss lagged behind weight loss, consistent with an initial leaching phase of decomposition. Both the FL and CC created wetlands exhibited faster litter decomposition than their adjacent forested wetland, however, the FL created wetland had a lower weight:area ratio and higher detritivore abundance than the adjacent forested wetland, while the reverse was true for the CC wetland pair. These relationships suggest macroinvertebrates played an important role in decomposition in the FL created wetland, while other factors were more significant at CC. Faster decomposition in the created wetlands may be of concern for long-term soil organic matter accumulation, or conversely, may indicate quick recovery of the litter decomposition function. Overall, these findings point out the difficulties involved in using certain functional indicators to compare very young and mature systems. / Master of Science

Deadwood, characterized as both downed woody material (DWM) and standing and dead stems, i.e., snags, is a significant component of terrestrial forest ecosystems. Deadwood amount and structure may influence potential wildfire hazard by altering combustible DWM mass and creating fuel structures that increase fire intensity and spread. Deadwood is also critical to carbon storage and nutrient cycling and may vary based upon the size classes of individual deadwood pieces. Lastly, deadwood structural variability has been found to positively affect species richness in bees, salamanders, birds, and small mammals, such as shrews and woodland mice. However, in the Mid-Atlantic Piedmont, there are no accessible tools to rapidly estimate deadwood of long unmanaged second growth forests to help inform future management decisions. Management agencies within this region, such as the National Park Service, may benefit from a greater understanding of the potential factors that influence deadwood accumulation, retention, and decomposition. Therefore, a project was funded by the National Park Service to investigate deadwood dynamics at Prince William Forest Park (PRWI). From May to August 2023, a deadwood inventory was conducted using planar intercepts nested within fixed radius plots along the gradient of forest cover types, aspect, elevation, and soil orders found within PRWI. Forest cover type was significant in the generalized linear model for percent dead basal area, total DWM, fine woody material, litter, and duff mass. The Virginia pine (Pinus virginiana) forest cover type had the highest percent dead basal area and total DWM mass per hectare. Elevation, aspect, and soil order were not significantly related to percent dead basal area, total DWM, 1,000 hr, fine woody material, litter, and duff mass. Data from this study may serve as a baseline for similar second growth forests of the mid-Atlantic Piedmont. / Master of Science / Visitors to Prince William Forest Park (PRWI) in eastern Virginia have voiced concern about forest health within PRWI. The perception of a high number of standing and dead stems, or snags, and a high number of decaying logs, branches, and twigs on the ground has been a focal point for visitors. Some perceive the dead material on the ground as a potential source of fuel for wildfires. Others perceive the potential hazard to humans along trails and vistas if snags were to fall. However, snags and downed woody material, known as deadwood, are critical components of forests because they store carbon and nutrients long-term and may provide habitat and resources for many wildlife species. Many other heavily used recreation locations in the eastern US face similar deadwood and forest health challenges. To respond to this, we assessed deadwood in PRWI to determine how it may be distributed differently across the variety of landscape features that are present within the park. We found the amount of total downed and dead material on the forest floor increased as the percentage of trees that were standing and dead increased. The amount of dead material on the ground was greatest for the Virginia pine (Pinus virginiana) forest community type, whereby PRWI's stands have reached their life expectancy. Prince William Forest Park's managers and those elsewhere at similar locations throughout the eastern US may benefit from this information as they seek to evaluate the status of their resources, manage those resources, and provide thoughtful messaging to the public regarding the significance and maintenance of deadwood as an ecosystem resource.

Experiments were conducted to monitor nutrient dynamics in the forest floor of an upland Appalachian oak forest stands following clearcutting and whole-tree removal. Samples from the L, F, H, and A₁ layers were collected during June, August, and November of 1979 and 1980. Monthly litterfall was collected from October, 1979, through October, 1980. Soil solution samples were extracted on a biweekly basis from April, 1980, through March, 1981, and concurrent soil moisture and temperature determinations were made. All samples were collected from the clearcut area and an adjacent uncut area. Nutrient analyses included total N, P, K, Ca, and Mg, and pH, NH₄-N, and NO₃-N for the soil solutions only. Comparisons were made between nutrient contents in the forest floor and mineral soil from the clearcut and uncut areas, between nutrient contents within forest floor layers within each area, and between nutrient contents collected over time within each area. Similar comparisons were made using litterfall nutrient contents and soil solution nutrient concentrations. Immediate clearcutting effects were most pronounced on the L layer of the forest floor, due to the logging slash input. Immediately after cutting the L layer in the cut area had a dry weight over 9,500 times that of the L layer in the uncut area. This logging slash rapidly became incorporated into the forest floor of the cut area, and after 15 months, the cut area had a forest floor slightly higher in dry weight and nutrient content than did the uncut area. Slash inputs accounted for these increases, since over the course of the study the cut area received only 14% of the litterfall that occurred in the uncut area. Soil temperature, moisture, and soil solution NH₄-N concentrations were all higher in the clearcut area. Soil solution NO₃-N concentrations were variable but generally the same in both areas. After 15 months following clearcutting and whole-tree removal, the forest floor in the clearcut area was slightly higher in dry weight and nutrient content than an adjacent uncut area, and no site degradation was noted. / Ph. D.

Nutrient runoff from excess land application of poultry litter in the Chesapeake Bay Watershed has caused damage to the Chesapeake Bay and lead to the need for alternative poultry litter disposal methods. This study provided an economic feasibility analysis of the use of poultry litter as a partial replacement of coal at an electrical generating unit in Virginia's Chesapeake Bay Watershed. Previous research on the feasibility of converting litter to energy failed to include uncertainty in benefit-cost variables, therefore, this study used risk analysis to incorporate variable uncertainty. Project net worth in previous studies was measured under a public investment scenario with risk neutral preferences but did not take into account risk averse preferences common in private investment. This paper compared benefits under both public risk neutral and private risk averse investor preferences. NPV results showed the proposed project to be feasible but sensitive to the acquisition cost of poultry litter, the unit ash value of litter, and future coal price projections. The maximum level of risk aversion required for feasibility increased when expected returns were measured on an investment scale compared to an annual income scale. Poultry litter combustion produced lower levels of NOx and SO₂ emissions compared to coal, therefore, emission allowance trading through the EPA market based trading programs generated additional benefits to the model and increased the maximum level of risk aversion permitted for feasibility. Results suggested the potential to dispose of 110 thousand tons of poultry litter per year from the Chesapeake Bay Watershed without violating EPA emission standards. / Master of Science