京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20962号 / 理博第4414号 / 新制||理||1634(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 湯本 貴和, 教授 古市 剛史, 教授 友永 雅己 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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The Great Dismal Swamp (GDS) is a forested peatland located in the Atlantic Coastal Plain. Once a mosaic of wetland communities, disturbances (e.g., timber harvesting and ditching) have resulted in altered hydrologic regime, homogenized forest communities, and increased peat subsidence. In response, hydrologic restoration and forest management aim to enhance community composition and function. To help inform these efforts, we investigated variability and drivers of forest communities by surveying vegetation composition and structure, hydrologic indicators, and soil properties at 79 monitoring plots across GDS. Data were augmented with modeled water levels and peat depths. Our results demonstrate red maple (Acer rubrum) dominance across GDS, which decreases tree density, richness, and diversity. However, hierarchical cluster analysis identified four community types: Gum (G), Maple-Gum (M-G), Sweetgum-Maple (SG-M), and Maple (M). These communities differed in tree composition and structure; differences in other growth forms (shrubs, herbaceous, and regeneration) were limited. Modeled water levels failed to explain vegetation differences, but community associations with soil properties suggest that communities exist along a hydrologic gradient. Specifically, the G community likely exists on wetter sites whereas SG-M communities occur at drier locations. Maple-dominated communities (M and M-G; 78% of plots) likely occur across broader hydrologic gradients, explaining their dominance. However, more characterization of hydrology (i.e., time-varying water levels and soil moisture) and other drivers (e.g., site history and soil hydraulics) is needed to further explain community variation. As such, we propose future strategies for long-term monitoring to inform ongoing hydrologic restoration and forest management efforts. / Master of Science / The Great Dismal Swamp (GDS) is a large forested wetland located in southeastern Virginia and northeastern North Carolina. The GDS provides many ecosystem services such as wildlife habitat, biodiversity, water quality and storage, and carbon storage. Prior to disturbance, the GDS was composed of a variety of forest types, including stands dominated by cypress (Taxodium spp.), cedar (Chamaecyparis spp.), and pocosin (Pinus spp.) species. However, land use activities (e.g., ditching, draining, and timber harvesting) have resulted in drier conditions, forests dominated by red maple (Acer rubrum), land subsidence, and increased fire frequency. To restore the GDS to its pre-disturbance state, water control structures have been installed in drainage ditches to increase wetland water levels throughout the swamp. To inform those efforts, research is needed to understand how forest communities will respond to changing hydrology. In this study, we investigated forest composition throughout the GDS and found that four forested communities exist: Gum (G), Maple-Gum (M-G), Sweetgum-Maple (SG-M), and Maple (M). Our findings demonstrate that the M community is the most abundant community at GDS. Where red maple is present in large quantities, the variety of other tree species decreases. Additionally, we found that these communities exist on different degrees of wetness. The G community is located on wet sites, and the SG-M is located on dry sites. The more mapledominated communities (M and M-G) are found across a larger range of wetness conditions. Our findings will inform future monitoring and management efforts at GDS.

Forested peatlands of the Great Dismal Swamp (GDS) have been greatly altered since colonial times, motivating recent restoration efforts. Community structure and function were hydrologically altered by 19th and 20th century ditches installed to lower water levels and enable early timber harvesting. Contemporary forest communities are comprised of maturing remnants from selective timber harvesting that ended in the early 1970s. Red maple (Acer rubrum) has become the dominant species across GDS, encroaching on or replacing the historical mosaic of cypress (Taxodium spp.)/tupelo (Nyssa spp.), Atlantic white-cedar (Chamaecyparis thyoides), and pocosin (Pinus spp.). Moreover, peat soil has been exposed to more unsaturated conditions resulting in carbon loss through decomposition and increased peat fire frequency and severity. Installation of ditch control structures aim to control drainage and re-establish historical hydrology, vegetation communities, peat accretion rates, and fire regime. To help inform restoration and management, we conducted two complimentary studies to test hypotheses regarding hydrologic influences on vegetation, peat depths, and peat fire vulnerability. First, we found thicker peat, lower maple importance, and higher species richness at wetter sites (e.g., higher mean water levels). In our second study, we evaluated the integrated effects of peat properties and water level dynamics on peat fire vulnerability. We found decreased burn vulnerability with increased wetness, suggesting that the driest sites were always at risk to burn, whereas the wettest sites never approached fire risk conditions. Together our findings demonstrate strong hydrologic controls on GDS ecosystem structure and function, thereby informing water level management for restoration goals. / Master of Science / Forested wetlands, like the Great Dismal Swamp (GDS) in eastern Virginia, provide valuable ecosystem services, including wildlife habitat, biodiversity, water quality and storage, carbon storage, and many others. Many of these ecosystems have been lost to land conversion, or hydrologically altered. Ditches installed to lower water levels and enable timber harvesting altered GDS ecosystem services. Lowered water levels changed the forest from a historical mosaic of diverse tree species to a more homogeneous forest dominated by one tree species, red maple. Moreover, GDS’s organic soil (peat) has been exposed to drier conditions resulting in carbon loss through decomposition and increased peat fire frequency and severity. To restore GDS ecosystem services, installation of water control structures in the ditches aim to control drainage and re-establish historical water levels (hydrology), forest cover, peat soil development rates, and fire regime. To help guide this hydrology management, we conducted two complimentary studies to test hypotheses regarding hydrology’s influences on vegetation, peat soil, and peat fire vulnerability. First, we found thicker peat soil, lower red maple prevalence, and more vegetation species at wetter sites. In our second study, we evaluated the integrated effects of peat soil properties and water level dynamics on peat fire vulnerability. We found decreased fire vulnerability with increased wetness, suggesting that the driest site was always at risk to burn, whereas the wettest site never approached conditions for fire risk. Together our findings demonstrate hydrology’s strong controls on GDS ecosystem services, thereby informing water level management for restoration goals.

Swamp rabbits (Sylvilagus aquaticus) are a bottomland hardwood forest specialist undergoing contraction at the northern extent of their range. This decline is often attributed to the loss of bottomland hardwood forest and frequent, intense flooding. To mitigate this decline and inform decisions regarding the swamp rabbit’s conservation status, there is a pressing need for long-term monitoring efforts. Although currently listed as imperiled (S2) in Missouri, shifts in occupancy trends may warrant a reassessment of the swamp rabbit’s state rank. The Missouri Department of Conservation has conducted decadal surveys for swamp rabbits since 1991, and the work presented here describes the fourth iteration of this study – 2022-2023. Repeated latrine surveys at 176 previously surveyed sites were conducted from November 2022 – April 2023 across 16 counties in southeast Missouri. Dynamic occupancy models were then used to estimate occupancy, colonization, extinction, and detection probabilities and identify environmental factors driving distribution changes since 2012. Additionally, I examined the impact of including ground latrines in swamp rabbit detection histories for the 2022-2023 survey season in a comparative single-season occupancy analysis. This analysis aimed to evaluate how the incorporation of ground latrines, as opposed to restricting detections to latrines on elevated surfaces, influenced estimates of occupancy and detection probabilities. Swamp rabbits were detected at 148 sites in 15 counties in 2022-2023, with a noted increase in occupancy probability from 0.66 (SE = 0.01) in 2010-2012 to 0.79 (SE = 0.01) in 2022-2023. As expected, site isolation negatively impacted occupancy probability, but predictors for patch richness density, site area, flood frequency, and flood severity had varying levels of support. For example, occupancy probability was negatively influenced by patch richness density but positively influenced by site area, while colonization probabilities were high and positively influenced by both flood frequency and severity. Extinction probability was low but was negatively influenced by flood frequency. Models with occupancy, colonization, and extinction as a function of the proportion of bottomland hardwood forest at a site were not supported. Detection probability decreased from 0.90 (SE = 0.19) in 2010-2012 to 0.78 (SE = 0.13) in 2022-2023. The inclusion of ground latrines in analyses did increase detection (0.68 to 0.84) and estimates of occupancy probabilities (0.95 to 1.00) but the change in estimates of occurrence was not biologically meaningful. Despite concerns about decline at the northern edge of their range, swamp rabbit populations in southeast Missouri appear to be expanding, evidenced by the increased occupancy and promising colonization and extinction rates. While long-term monitoring efforts should continue, managers should consider changing the swamp rabbit’s state rank from imperiled (S2) to vulnerable (S3).

Com o objetivo de compreender quais fatores abióticos determinam a ocorrência das diferentes formações florestais na região de Batatais, entre as coordenadas 20038S e 20058S e 47037W e 47028W, foram escolhidas três propriedades agrícolas (Fazenda Monte Belo, em Restinga, SP e Fazenda Magnólia e Sítio Pratinha, em Batatais, SP), que apresentavam remanescentes florestais representativos da região (floresta ribeirinha paludícula, floresta estacional semidecídua ribeirinha e cerradão). Para descrever a composição florística e a estrutura da comunidade arbórea foram amostradas 05 parcelas de 10 x 10 m ao redor de cada estação tensiométrica. Para o estudo dos fatores abióticos foram determinados os parâmetros físicos e químicos dos solos e as curvas de retenção de água nos solos e piezometria. A discriminação das variáveis abióticas e de vegetação foi feita através da análise de componentes principais (PCA) e, na correlação entre a abundância de espécies e fatores abióticos, foram feitas análises diretas de gradiente por meio de Análise de Correlação Canônica (CCA). A textura dos solos (teores de argila, silte e areia) e a posição no terreno (cota), foram as variáveis ambientais mais importantes na distribuição das espécies e nas variações das fisionomias florestais, com influência na retenção hídrica e nos índices de fertilidade dos solos. Essas diferenças nos teores de argila em profundidade ao longo do declive, com influência direta na retenção de umidade dos solos ou mesmo na formação de ambientes paludículos, determinaram grupos distintos de espécies e fisionomias florestais: (i) um grupo de espécies de ocorrência típica nas fisionomias de Cerrado e fortemente associado às cotas mais elevadas (solos menos férteis, bem drenados e porcentagens mais baixas de argila e silte nas camadas mais profundas), entre as quais: Matayba juglandifolia, Trichilia pallida, Lithraea molleoides, Anadenanthera falcata, Myrcia tomentosa, Copaifera langsdorffii, Erytrhoxylum pelleteranum, Platipodium elegans, Chrysophyllum marginatum, Luehea divaricata, entre outras e (ii) um grupo com espécies indicadoras de Florestas Paludículas ou de ocorrência comum nestas fisionomias, associado aos solos das cotas mais baixas (Gleissolos), com porcentagens altas de argila e silte nas camadas superficiais, mais férteis e maior retenção hídrica: Cecropia pachystachya, Citronella gongonha, Rapanea guianensis, Talauma ovata e Tapirira guianensis. Pode-se considerar um terceiro grupo de transição entre Floresta Estacional Semidecídua e Cerradão, nas cotas intermediárias e menos úmidas (espécies amostradas em parcelas localizadas nas bordas das Florestas Paludículas), onde ocorreram espécies tanto de ambiente de Cerradão, como de Floresta Estacional Semidecídua, e algumas poucas de ambiente paludículo. As porcentagens mais elevadas de Areia nos solos do Sítio Pratinha, com influência na menor retenção hídrica e também nos índices de fertilidade (solos álicos, com maior acidez e os menos férteis), podem explicar algumas diferenças na composição e abundância das espécies entre fisionomias florestais iguais. O Cerradão da Fazenda Monte Belo, mostrou-se diferente floristicamente do Cerradão do Sítio Pratinha. Esta mesma diferença ocorreu em relação às Florestas Paludículas da Fazenda Magnólia e a do Sítio Pratinha. As poucasespécies de ocorrência comum tiveram populações diferentes. A CCA evidenciou também correlações de algumas espécies com determinadas variáveis de solo. / In order to understand what abiotic factors determine the occurrence of different forest formations in the region of Batatais, coordinated between 20038\'S and 20058\'S and 47037\'W and 47028\'W, three agricultural properties were chosen (Monte Belo, in the city of Restinga, SP and Magnolia and Pratinha in Batatais, SP, Brazil), which had forests representative of the region (swamp forest, semi-deciduous riverine forest and forested savanna). To describe the floristic composition and structure of the arboreal community, 05 plots of 10 x 10 meters around each tensiometric station were sampled. For the study of abiotic factors, the physico-chemical characteristics of the soils, the soil-water-retention curves and the groundwater fluctuation were determined. The discrimination of the environmental variables and arboreal species were made through the Principal Components Analysis (PCA), and in the correlation between the abundance of species and abiotic factors, direct analyses of gradient through Canonical Correspondence Analysis (CCA) were made. The texture of the soil (levels of clay, silt and sand) and the position on the ground (altitude) were the most important environmental variables in the distribution of species and variations of forest physiognomies, with influence in the retention rates of water and soil fertility. These differences in levels of clay in depth along the slope, with direct influence on the retention of soil moisture and even in the development of swampy environment, determined distinct groups of species and forest physiognomies: (i) a group of species of typical occurrence in physiognomies of Forested Savanna and strongly associated with higher altitude (less fertile, well-drained soil and lower percentages of clay and silt in the deeper layers), including: Matayba juglandifolia, Trichilia pallida, Lithraea molleoides, Anadenanthera falcata, Myrcia tomentosa, Copaifera langsdorffii, Erytrhoxylum pelleteranum, Platipodium elegans, Chrysophyllum marginatum, Luehea divaricata, among others, and (ii) a group with indicator species of Swamp Forests or common occurrence in these physiognomies, associated with lower altitude (Gleisoil), with high percentages of clay and silt in the upper and more fertile layers, and greater water retention: Cecropia pachystachya, Citronella gongonha, Rapanea guianensis, Talauma ovata and Tapirira guianensis. A third group of transition between Semi-deciduous Forest and Forested Savanna, in intermediate altitude and soils less humid (species sampled in plots located at the edges of Swamp Forests), occurred both in the Forested Savanna and in Semi-deciduous Forest and a few in swampy environment. The highest percentages of sand in the soil of Pratinha, with less influence on water retention and also on the rates of fertility (alic soils, with greater acidity and less fertile), may explain some differences in the composition and abundance of species of forest physiognomies equal. The forested Savanna of Monte Belo, has proved floristically different from the Forested Savanna of Pratinha. This same difference occurred in swamp forests of Magnolia and Pratinha. The few species of common occurrence had differentpopulations. The CCA also revealed correlations of some species with certain variables of soil.

Reclamation of surface mined lands is required under the Surface Mining Control and Reclamation Act of 1977. Reforestation of mined lands is challenging due to harsh conditions such as soil compaction, herbaceous competition, and animal browse. We investigated the field performance of black walnut (<i>Juglans nigra</i>), northern red oak (<i>Quercus rubra</i>), and swamp white oak (<i>Quercus bicolor</i>) planted on two mine reclamation sites and evaluated the interactions of nursery stocktypes (container and bareroot), herbicide application, and tree shelters. Survival averaged 80% across all species and stocktypes after two years. Container stocktype had greater relative height and diameter growth, whereas bareroot had greater total height and diameter growth likely due to initial stocktype differences. Shelter use increased height growth and reduced diameter growth across both stocktypes. Swamp white oak (<i>Q. rubra</i>) had high survival and field performance regardless of silvicultural treatment, whereas the two other species showed strong early regeneration responses to silvicultural treatments. Container seedlings showed promise as an alternative to bareroot seedlings to promote survival and early growth on mine reclamation sites. Future research should be on continued development of container stocktypes to provide an economically feasible mine reclamation option for land managers.

The aim of this report is to describe the elemental composition and C:N:P stoichiometry of soil organic matter and microbial biomass in spruce swamp forests in the National Park Šumava and to find out whether they are affected by a presence of different plant dominants in the understory - peat moss, cotton-grass and blueberry. Samplings were made at three locations in the spring, summer and autumn of 2013. The work was a part of the project funded by the GA CR.

Com o objetivo de compreender quais fatores abióticos determinam a ocorrência das diferentes formações florestais na região de Batatais, entre as coordenadas 20038S e 20058S e 47037W e 47028W, foram escolhidas três propriedades agrícolas (Fazenda Monte Belo, em Restinga, SP e Fazenda Magnólia e Sítio Pratinha, em Batatais, SP), que apresentavam remanescentes florestais representativos da região (floresta ribeirinha paludícula, floresta estacional semidecídua ribeirinha e cerradão). Para descrever a composição florística e a estrutura da comunidade arbórea foram amostradas 05 parcelas de 10 x 10 m ao redor de cada estação tensiométrica. Para o estudo dos fatores abióticos foram determinados os parâmetros físicos e químicos dos solos e as curvas de retenção de água nos solos e piezometria. A discriminação das variáveis abióticas e de vegetação foi feita através da análise de componentes principais (PCA) e, na correlação entre a abundância de espécies e fatores abióticos, foram feitas análises diretas de gradiente por meio de Análise de Correlação Canônica (CCA). A textura dos solos (teores de argila, silte e areia) e a posição no terreno (cota), foram as variáveis ambientais mais importantes na distribuição das espécies e nas variações das fisionomias florestais, com influência na retenção hídrica e nos índices de fertilidade dos solos. Essas diferenças nos teores de argila em profundidade ao longo do declive, com influência direta na retenção de umidade dos solos ou mesmo na formação de ambientes paludículos, determinaram grupos distintos de espécies e fisionomias florestais: (i) um grupo de espécies de ocorrência típica nas fisionomias de Cerrado e fortemente associado às cotas mais elevadas (solos menos férteis, bem drenados e porcentagens mais baixas de argila e silte nas camadas mais profundas), entre as quais: Matayba juglandifolia, Trichilia pallida, Lithraea molleoides, Anadenanthera falcata, Myrcia tomentosa, Copaifera langsdorffii, Erytrhoxylum pelleteranum, Platipodium elegans, Chrysophyllum marginatum, Luehea divaricata, entre outras e (ii) um grupo com espécies indicadoras de Florestas Paludículas ou de ocorrência comum nestas fisionomias, associado aos solos das cotas mais baixas (Gleissolos), com porcentagens altas de argila e silte nas camadas superficiais, mais férteis e maior retenção hídrica: Cecropia pachystachya, Citronella gongonha, Rapanea guianensis, Talauma ovata e Tapirira guianensis. Pode-se considerar um terceiro grupo de transição entre Floresta Estacional Semidecídua e Cerradão, nas cotas intermediárias e menos úmidas (espécies amostradas em parcelas localizadas nas bordas das Florestas Paludículas), onde ocorreram espécies tanto de ambiente de Cerradão, como de Floresta Estacional Semidecídua, e algumas poucas de ambiente paludículo. As porcentagens mais elevadas de Areia nos solos do Sítio Pratinha, com influência na menor retenção hídrica e também nos índices de fertilidade (solos álicos, com maior acidez e os menos férteis), podem explicar algumas diferenças na composição e abundância das espécies entre fisionomias florestais iguais. O Cerradão da Fazenda Monte Belo, mostrou-se diferente floristicamente do Cerradão do Sítio Pratinha. Esta mesma diferença ocorreu em relação às Florestas Paludículas da Fazenda Magnólia e a do Sítio Pratinha. As poucasespécies de ocorrência comum tiveram populações diferentes. A CCA evidenciou também correlações de algumas espécies com determinadas variáveis de solo. / In order to understand what abiotic factors determine the occurrence of different forest formations in the region of Batatais, coordinated between 20038\'S and 20058\'S and 47037\'W and 47028\'W, three agricultural properties were chosen (Monte Belo, in the city of Restinga, SP and Magnolia and Pratinha in Batatais, SP, Brazil), which had forests representative of the region (swamp forest, semi-deciduous riverine forest and forested savanna). To describe the floristic composition and structure of the arboreal community, 05 plots of 10 x 10 meters around each tensiometric station were sampled. For the study of abiotic factors, the physico-chemical characteristics of the soils, the soil-water-retention curves and the groundwater fluctuation were determined. The discrimination of the environmental variables and arboreal species were made through the Principal Components Analysis (PCA), and in the correlation between the abundance of species and abiotic factors, direct analyses of gradient through Canonical Correspondence Analysis (CCA) were made. The texture of the soil (levels of clay, silt and sand) and the position on the ground (altitude) were the most important environmental variables in the distribution of species and variations of forest physiognomies, with influence in the retention rates of water and soil fertility. These differences in levels of clay in depth along the slope, with direct influence on the retention of soil moisture and even in the development of swampy environment, determined distinct groups of species and forest physiognomies: (i) a group of species of typical occurrence in physiognomies of Forested Savanna and strongly associated with higher altitude (less fertile, well-drained soil and lower percentages of clay and silt in the deeper layers), including: Matayba juglandifolia, Trichilia pallida, Lithraea molleoides, Anadenanthera falcata, Myrcia tomentosa, Copaifera langsdorffii, Erytrhoxylum pelleteranum, Platipodium elegans, Chrysophyllum marginatum, Luehea divaricata, among others, and (ii) a group with indicator species of Swamp Forests or common occurrence in these physiognomies, associated with lower altitude (Gleisoil), with high percentages of clay and silt in the upper and more fertile layers, and greater water retention: Cecropia pachystachya, Citronella gongonha, Rapanea guianensis, Talauma ovata and Tapirira guianensis. A third group of transition between Semi-deciduous Forest and Forested Savanna, in intermediate altitude and soils less humid (species sampled in plots located at the edges of Swamp Forests), occurred both in the Forested Savanna and in Semi-deciduous Forest and a few in swampy environment. The highest percentages of sand in the soil of Pratinha, with less influence on water retention and also on the rates of fertility (alic soils, with greater acidity and less fertile), may explain some differences in the composition and abundance of species of forest physiognomies equal. The forested Savanna of Monte Belo, has proved floristically different from the Forested Savanna of Pratinha. This same difference occurred in swamp forests of Magnolia and Pratinha. The few species of common occurrence had differentpopulations. The CCA also revealed correlations of some species with certain variables of soil.