As alterações no uso do solo decorrentes das atividades humanas modificam as condições ambientais, o que pode levar a mudanças na estrutura de comunidades locais. A expansão da silvicultura ao redor do mundo tem causado uma crescente preocupação em termos de conservação da biodiversidade. Isto por que ela resulta em uma simplificação e homogeneização do habitat originalmente nativo. Este estudo avaliou a estrutura da assembleia de aves em áreas de silvicultura e em floresta nativa, sendo que os principais objetivos foram: 1) avaliar o possível impacto da silvicultura sobre a riqueza, abundância e composição de espécies de aves, considerando diferentes idades de plantio; 2) avaliar se as espécies de aves registradas em áreas de silvicultura representam um subconjunto daquela registrada na floresta nativa; 3) analisar as respostas da diversidade funcional e dos atributos funcionais morfológicos e comportamentais das espécies de aves. Foram amostrados plantios de eucalipto de quatro idades de cultivo assim como áreas de floresta nativa num total de 150 pontos de escuta. A riqueza, a abundância de espécies de aves e a diversidade funcional foram significativamente maiores na floresta nativa. A composição de espécies também apresentou diferença significativa entre a floresta e os plantios de diferentes idades. Entretanto apesar da diferença na composição, as espécies que ocorrem nos plantios de eucalipto representam subconjuntos daquelas encontradas na floresta nativa, com um elevado índice de aninhamento para os plantios de idade mais avançada. Os resultados deste estudo indicam a ação de um filtro ambiental imposto pela silvicultura, selecionando espécies com requerimentos de habitat e atributos similares, assim como um maior número de espécies generalistas de habitat. Pode-se inferir então que áreas de silvicultura oferecem um habitat pouco complexo para a avifauna com um nível limitado de recursos e com isso, uma perda de funções ecológicas essenciais ao ambiente, como a dispersão de sementes. / Changes in land use resulting from human activities modify the environmental conditions, which can lead to changes in the structure of local communities. The expansion of silviculture around the world has caused a growing concern for biodiversity conservation. This is because it results in a simplification and homogenization of originally native habitat. This study evaluated the structure of the assembly of birds in areas of native forest and silviculture, and the main objectives were : 1) to evaluate the possible impact of silviculture on the richness, abundance and composition of bird species, with different ages of planting and 2) assess whether the bird species recorded in areas of silviculture represent a subset that recorded in native forest, 3) analyze the responses of functional diversity and functional morphological and behavioral traits of birds species. Eucalyptus plantations four ages of cultivation as well as areas of native forest in a total of 150 point counts were sampled. The richness, abundance of bird species and functional diversity were significantly higher in the native forest. The species composition also showed a significant difference between the forest and plantations of different ages. However despite the difference in composition, species that occur in eucalyptus plantations represent subsets of those found in the native forest, with a high level of nestedness for plantations older age. The results of this study indicate the action of an environmental filter arising for silviculture, selecting species with similar habitat requirements and traits, as well as a greater number of generalist species habitat. It can be inferred then that silviculture areas offer a bit complex habitat for birdlife with a limited amount of resources and thus, a loss of ecological functions essential to the environment, such as seed dispersal.

Once dominant, longleaf pine forests of the southeastern United States have been modified by 97 percent, resulting in several animal species being listed as endangered and threatened. Pine plantation silviculture (tree plantings) now occupies half of the original longleaf range where several animal species of conservation concern have experienced recent local population declines. In North America, the accepted practice of pine plantations is to plant pines densely in rows for wood production. Given that land use is considered a primary local driver for the 30% of amphibian species currently at risk of extinction, and planted pine is predicted to expand coverage by 2020, sustainable land management will require integrating ecological and economic goals, including conservation objectives. To understand how amphibian species characteristic of longleaf pine forest are affected by planted pine forestry, it is necessary to understand how associated shifts in habitat structure associated with aging pine stands influence species composition across a wide geographic area, especially populations of rare species. The purpose of this dissertation is to examine how forest structure (natural regeneration vs plantation) affects amphibian species composition and occupancy of small isolated wetlands embedded within the forest. Particular emphasis is placed on assessing several potential causal mechanisms of regional declines in amphibian species. This study was performed on Florida public forests where active forest management is a potential conservation tool and historic populations of rare amphibians occur. Sites where occupancy was assessed included: Goethe State Forest, Ocala National Forest, Jennings State Forest, Saint Marks National Wildlife Refuge, and Apalachicola National Forest. Withlacoochee State Forest was used for examining potential causal mechanisms of amphibian declines because of close proximity of reference condition forest to planted pine. Chapter One of this dissertation uses Objective Based Vegetation Monitoring (OBVM) metrics to quantify differences in forest habitat structure surrounding study sites (among planted pines and naturally regenerated second growth pine) and relationships between vegetation metrics. Increased basal area of planted pine resulted in decreased canopy openness and a significant decrease of ground cover, especially wiregrass. Serenoa repens petiole counts and percent cover of woody shrubs also significantly decreased wiregrass cover, and variance partitioning indicated that the effects of woody shrub invasion and pine basal area on wiregrass were independent on public forests. Absence of bare ground because of pine needle litter was a significant predictor of wiregrass absence in a zero-inflated negative binomial model (ZINB). ZINB predictions for wiregrass cover along a gradient of pine basal area and woody shrub abundance demonstrated the importance of habitat management for native groundcover on public forests. OBVM metrics were often positively correlated within the canopy, subcanopy, and groundcover categories. Chapter Two presents the results of site occupancy modeling comparing the presence of 10 species of amphibians in planted pine and naturally regenerated forest, focusing on the influence of canopy and groundcover habitat structure on occupancy of individual amphibian species. Amphibian species of greatest conservation need (SGCN) in Florida adapted to xeric soils, i.e. the gopher frog (Lithobates capito) and striped newt (Notophthalmus perstriatus), were found where basal tree areas were below 10.3 m2/ha, and a mesic amphibian SGCN, the ornate chorus frog (Pseudacris ornata), was found at pine basal areas up to 13.1 sq. m2/ha. All SGCN were found at sites with average woody shrub cover below four percent, and litter cover below 80 percent. Wiregrass cover was higher than four and six percent per m2 at sites with L. capito and N. perstriatus, respectively. Of 33 site detections for SGCN, only three sites had < 2.5 m2 wiregrass cover. Only one species, the pinewoods treefrog (Hyla femoralis), was more common on planted pine stands, and both Lithobates sphenocephala and L. grylio had constant probability of occupancy regardless of forest type. Percent wiregrass cover was a significant predictor of occupancy for five species, particularly for State listed species L. capito and N. perstriatus, suggesting it may be a useful indicator of habitat quality for longleaf-dependent amphibians. Chapter Three focuses on experimental release of juvenile southern toads into two types of terrestrial enclosures to independently determine if amphibian movement and desiccation is determined by forest management. Movement enclosures consisted of four 50 m x 2.5 m unidirectional runways joined at the center to determine movement rate, distance, and behavior among forests of varying habitat structure. Movement rates were relatively consistent among forest types and positively related to rainfall, which itself did not vary among forests. Canopy closure and ground slope were predictors of behavior as toads move preferentially toward canopy openings and negative slopes, particularly when in planted pine habitat. Ten desiccation enclosures, each 15 cm diameter by 45 cm tall, were used to determine water loss and survival of toads for up to 72 hours. The proportional water loss from toad bodies was significantly related to ambient soil moisture at enclosures, with moisture consistently less at planted pines sites in xeric soil, suggesting a potential source of mortality for species specialized to sandhills. Juvenile survival was particularly low at sandhills planted with pine where dry duff replaced native groundcover and likely prevented successful water conservation behavior. The results of these studies suggest that land management decisions related to planted pine forests will determine the species composition at embedded isolated wetlands for both rare and common amphibians. As natural disturbance regimes that limit woody shrub invasion are replaced by plantation silviculture tree plantings that further decrease light transmittance, native groundcover is reduced to greater extent than stands allowed to naturally regenerate following past timber harvest. Current and predicted expansion of pine plantation will particularly limit occupancy for amphibian SGCN endemic to sandhills, where planting dense pines lowers ambient soil moisture and juvenile survival. The vegetation metrics presented will allow land managers to guide forests toward conservation goals, to predict suitability of forests for amphibian species, and enhance success when repatriation efforts are needed. The significant relationship of amphibian occupancy to sensitive herbaceous vegetation (wiregrass) highlights that greater emphasis on forest groundcover is needed where amphibian SGCN occur and that cumulative impacts of forest management on native groundcover should be considered.

Wildfire is the primary natural disturbance in Interior Cedar-Hemlock (ICH) forests, and since the mid-20th century, forest harvesting (clearcutting, in this case) has become the primary anthropogenic disturbance type. Forest management in British Columbia is currently governed by a paradigm that maintains that biological diversity can be preserved by utilizing forest harvesting regimes that closely mimic "natural" disturbance regimes, but a question remains as to how closely these regimes mimic wildfire disturbances. More specifically, how do clearcutting and wildfires compare in their effects on the structure and composition of early-successional ICH plant communities? This study compares vegetation structure, composition, relative abundance and diversity among 39 sites that experienced either a stand-replacing fire or a clearcut within the last 40 years. Sites of different ages and disturbance types were located within the wet cool ICHwkl and very-wet cool ICHvk I biogeoclimatic variants near Revelstoke, B.C. For each site, overstory structural characteristics (tree and snag diameters, basal area and density), overstory composition, and surface fuels (volume of coarse woody debris (CWD)) were assessed. Understory vegetation percent cover, species richness, composition and diversity were also determined. Linear regression analysis was used to examine differences in each of these variables between disturbance types, over time. The trends in structural legacies (especially snag and CWD dynamics) varied greatly between wildfire and clearcut sites. Compared to burned sites, clearcut sites exhibited patterns of accelerated succession in several characteristics (overstory tree regeneration, vegetation cover and understory species richness) due to planting treatments and pre-disturbance relicts. Understory species composition also varied between disturbances, with clearcut sites containing more shade-tolerant survivors initially. Both disturbance types had similar levels of floristic diversity during early succession. These results suggest that clearcut harvesting may not emulate stand-replacing fires in terms of impact on early ICH plant succession in any aspect but diversity. However, it is unclear if these early-successional differences will continue through time. There is a need for further research in this ecosystem, as well as any other ecosystems where emulation silviculture is applied, in order to confirm that silvicultural effects mimic those of natural disturbance regimes. / Forestry, Faculty of / Graduate

As alterações no uso do solo decorrentes das atividades humanas modificam as condições ambientais, o que pode levar a mudanças na estrutura de comunidades locais. A expansão da silvicultura ao redor do mundo tem causado uma crescente preocupação em termos de conservação da biodiversidade. Isto por que ela resulta em uma simplificação e homogeneização do habitat originalmente nativo. Este estudo avaliou a estrutura da assembleia de aves em áreas de silvicultura e em floresta nativa, sendo que os principais objetivos foram: 1) avaliar o possível impacto da silvicultura sobre a riqueza, abundância e composição de espécies de aves, considerando diferentes idades de plantio; 2) avaliar se as espécies de aves registradas em áreas de silvicultura representam um subconjunto daquela registrada na floresta nativa; 3) analisar as respostas da diversidade funcional e dos atributos funcionais morfológicos e comportamentais das espécies de aves. Foram amostrados plantios de eucalipto de quatro idades de cultivo assim como áreas de floresta nativa num total de 150 pontos de escuta. A riqueza, a abundância de espécies de aves e a diversidade funcional foram significativamente maiores na floresta nativa. A composição de espécies também apresentou diferença significativa entre a floresta e os plantios de diferentes idades. Entretanto apesar da diferença na composição, as espécies que ocorrem nos plantios de eucalipto representam subconjuntos daquelas encontradas na floresta nativa, com um elevado índice de aninhamento para os plantios de idade mais avançada. Os resultados deste estudo indicam a ação de um filtro ambiental imposto pela silvicultura, selecionando espécies com requerimentos de habitat e atributos similares, assim como um maior número de espécies generalistas de habitat. Pode-se inferir então que áreas de silvicultura oferecem um habitat pouco complexo para a avifauna com um nível limitado de recursos e com isso, uma perda de funções ecológicas essenciais ao ambiente, como a dispersão de sementes. / Changes in land use resulting from human activities modify the environmental conditions, which can lead to changes in the structure of local communities. The expansion of silviculture around the world has caused a growing concern for biodiversity conservation. This is because it results in a simplification and homogenization of originally native habitat. This study evaluated the structure of the assembly of birds in areas of native forest and silviculture, and the main objectives were : 1) to evaluate the possible impact of silviculture on the richness, abundance and composition of bird species, with different ages of planting and 2) assess whether the bird species recorded in areas of silviculture represent a subset that recorded in native forest, 3) analyze the responses of functional diversity and functional morphological and behavioral traits of birds species. Eucalyptus plantations four ages of cultivation as well as areas of native forest in a total of 150 point counts were sampled. The richness, abundance of bird species and functional diversity were significantly higher in the native forest. The species composition also showed a significant difference between the forest and plantations of different ages. However despite the difference in composition, species that occur in eucalyptus plantations represent subsets of those found in the native forest, with a high level of nestedness for plantations older age. The results of this study indicate the action of an environmental filter arising for silviculture, selecting species with similar habitat requirements and traits, as well as a greater number of generalist species habitat. It can be inferred then that silviculture areas offer a bit complex habitat for birdlife with a limited amount of resources and thus, a loss of ecological functions essential to the environment, such as seed dispersal.

Droughts are a common disturbance experienced by forest systems across the southeastern United States and are expected to increase in frequency in the near future. Few empirical studies have evaluated the response of individual tree resistance and resilience following silvicultural treatment in longleaf pine (Pinus palustris Mill.). This study evaluates the differences in drought responses between two forests during three different periods. The first period evaluated pretreatment (2000) conditions, while the second (2006), and third (2011) compared conditions after the implementation of five silvicultural treatments. The main findings are that, as additional basal area is removed, both individual tree resistance and resilience to drought increase. Moreover, as drought intensity decreases, both resistance and resilience metrics increase. Finally, higher competitive status of individual trees warranted higher resistance to drought compared to trees of a lower competitive status.

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.

The overall goal of this project was to provide baseline data on amphibian species richness, relative abundance, and habitat use for a long-term landscape ecology study on MeadWestvaco industrial forest in the Allegheny Highlands of West Virginia. From results of area-constrained daytime searches (10 m x 10 m plots) across the landscape, I developed 9 regression models to predict amphibian relative abundance. I constructed models for each year for all plots on all habitat types, plots that were in a Stream Management Zone (SMZ), and plots that were in upland, or non-SMZ, habitat. Distance to perennial or ephemeral streams or perennial ponds (SMZ classification), the amount of available rocks along transects, and site index were the 3 most important habitat variables in models for all plots combined and were responsible for 24-32% of the inherent variation in population relative abundance. Other habitat variables that were significant in models were year, % canopy cover, the amount of available woody debris of decomposition classes 3-5 along transects, % woody stems (<7.5 cm DBH), soil pH, and % herbaceous vegetation. R2PRESS values for all 9 models ranged from 0.08 to 0.35. Amphibian relative abundance showed positive relationships with all significant habitat variables with the exception of year and % woody stems. In natural cover object use/availability analyses, I discovered salamanders preferred rocks over woody debris, relative to the amount available of each. Salamanders preferred flat rocks to any other shape, flagstones to any other type of rock, and rock lengths in the 31-40 cm class. Preferred wood widths were in class 5-10 cm, while preferred wood lengths were in class <50 cm; salamanders exhibited strong preferences for wood in higher states of decomposition (class 3-5). I provided baseline, preharvest data for 28-acre reference areas on 9 forest compartments scheduled for clearcuts. I sampled all 9 reference areas preharvest and sampled 3 during year 1 postharvest using coverboard and night plot surveys. On these 3 areas, species richness declined from preharvest to postharvest, but species diversity showed little change. Overall relative abundance declined significantly preharvest to postharvest with coverboard sampling (p=0.0172) and night plot sampling (p=0.0113). At coverboard stations, relative abundance declined significantly from preharvest to postharvest at a distance of 5-10 m (p=0.0163) and 40-50 m (p=0.0193) away from adjacent mature forest. Finally, using Pianka's index, I compared the night plot and coverboard sampling techniques in terms of proportions of the 4 most common species captured. These sampling techniques on average were >80% similar for all reference areas. / Master of Science

To protect the integrity of the United State's waters, the Federal Water Pollution Control Act of 1972 promoted the establishment of Best Management Practices (BMPs) for forestry. A commonly used BMP is the reservation of Streamside Management Zones (SMZs). In this study the effectiveness of three different SMZ widths, 30.5 m (100 ft), 15.3 m (50 ft), and 7.6 m (25 ft), as well as thinning in 15.3 m SMZs were studied. The objectives of the study were to determine the effects these SMZ treatments had on carbon pools, carbon fluxes and environmental conditions in the SMZ. The benthic macroinvertebrate populations present within the stream were also examined because of their relationship to ecosystem carbon dynamics. Carbon storage in plant communities, litter layer, soil (upper 10 cm), and total organic carbon present (TOC) within streams were measured and quantified. Total CO₂ efflux and the major environmental drivers of soil CO₂ efflux, soil moisture and soil temperature, were monitored along a single transect within each SMZ. This study showed that carbon dynamics and stream biota (benthic macroinvertebrates) were not adversely effected by more narrow SMZ width and thinning within the SMZ. SMZ width did affect soil temperature, one of the environmental drivers affecting soil respiration. Based on these short-term results a 15.3 m SMZ with thinning or without thinning appears adequate to prevent changes in ecosystem function and water quality for forest applications. / Master of Science

In the interest of maintaining lands to fully support the military mission, Department of Defense (DOD) installations must manage competing objectives under constraints related to mission operations, regulation and compliance requirements, and budget reductions. Silviculture offers promise for ecosystem management while providing financial means through the sale of forest products. This study used forest inventory and bald eagle nest site data to investigate the potential effects of silviculture on bald eagle nesting habitat at Naval Support Facility Indian Head. Mahalanobis distance was used to define and classify preferred nesting substrate. Silviculture was simulated using the Forest Vegetation Simulator (FVS) to assess forest nesting substrate, economic yields and the tradeoffs between these two objectives. An alternative substrate model based on cumulative distribution functions (CDFs) and Boolean logic allowed evaluation of the strengths and weaknesses of the Mahalanobis distance method. The Mahalanobis distance model provided greater relative fit to the sample of nest sites compared to the CDF model but had lower discriminating power between presence and absence data. Simulation results indicate that top performing silvicultural treatments resulted in greater substrate availability compared to no-action over equal time periods. Uneven-age management was shown as the best system for providing nesting substrate as well as favorable economic yields in hardwood stands. Results also stress the importance of thinning in providing future nesting substrate and maintaining preferred substrate late in the rotation. Economic and habitat tradeoffs varied by treatment, suggesting that optimum prescriptions could be identified to provide for both objectives and minimize tradeoffs. / Master of Science

Silvicultural activities, particularly forest harvesting operations, have the potential to negatively impact water quality. In order to lessen the probability that water quality degradation will occur, a suite of best management practices has been developed and adopted by southeastern states. The Clean Water Act exempts silvicultural activities from the permitting process of Section 404 as long as federally accepted best management practices are implemented to control nonpoint source pollutants. To demonstrate that these practices are being implemented, states are now inspecting and reporting on best management practice usage on a state wide basis. The Environmental Protection Agency is responsible for executing the Clean Water Act and would like to use the information provided by the individual states to guide water quality protection programs at a regional scale since states have developed their own unique methods or reporting. Currently there it is difficult to compare the information provided by states, and this impedes further development of water quality protection programs. To address this issue, a state of the art review of current inspection and monitoring methods in the southeast was conducted. Forestry professionals were then surveyed to identify opportunities for standardization in the inspection and reporting methodologies employed by states. Using the information resulting from the review and survey, recommendations for standardization were made in the following areas: site selection criteria, field execution method, form design, best management practices evaluated and water quality threat assessment. A standardized form was also developed and tested across three physiographic regions. This information is helpful for future planning and modifications that state agencies can use to standardize their BMP implementation monitoring methods. / Master of Science