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Author: Robyn Ann Mikita Publisher: ISBN: Category : Soil microbiology Languages : en Pages : 174
Book Description
As the threat of wildfires in the United States increases due to global warming, understanding their effects on the soil biological community becomes central to recovery efforts. Therefore, it is important to study microbial community dynamics in forest soils impacted by fires from the view of elucidating how the new state compares with the original state of the microbial community. For this study, wildfires were hypothesized to cause a shift in the microbial community structure with dominant microbes being those best capable of responding to changes in their environment caused by the perturbation. The objectives of this research were to examine the recovery of the forest soil microbial communities after a wildfire and to investigate the state of the communities more than two years post-fire. After a wildfire occurred in the New Jersey Pinelands in 2007, soil samples were collected from the organic and mineral layers of two severely burned sites and an unburned control site over the span of two years following the fire. Microbial community composition was evaluated by principal component analysis and multivariate analysis of variance of molecular fingerprint data for bacterial, archaeal, and fungal-specific amplicons from denaturing gradient gel electrophoresis. The bacterial communities in the samples collected from 2 and 5 months following the fire clustered separately from those collected 13 and 17 months post-fire in two-dimensional space, indicating that the soil bacterial community structure changed with time following the fire. Deeper evaluation of the bacterial, archaeal, and fungal community patterns revealed that even though there were common bands between the unburned and the severely burned samples, the community structure of the samples from the unburned site grouped separately from those of the severely burned sites collected 2, 13, and 25 months post-fire. Generally, the microbial community composition in the unburned samples did not change significantly over two years. These data support the hypothesis that the soil microbial community was selected by both the direct and indirect effects associated with the wildfire in the initial two years after the perturbation. Rather than return to the predisturbance state, the soil microbial communities may reflect an alternate state two years following the fire.
Author: Robyn Ann Mikita Publisher: ISBN: Category : Soil microbiology Languages : en Pages : 174
Book Description
As the threat of wildfires in the United States increases due to global warming, understanding their effects on the soil biological community becomes central to recovery efforts. Therefore, it is important to study microbial community dynamics in forest soils impacted by fires from the view of elucidating how the new state compares with the original state of the microbial community. For this study, wildfires were hypothesized to cause a shift in the microbial community structure with dominant microbes being those best capable of responding to changes in their environment caused by the perturbation. The objectives of this research were to examine the recovery of the forest soil microbial communities after a wildfire and to investigate the state of the communities more than two years post-fire. After a wildfire occurred in the New Jersey Pinelands in 2007, soil samples were collected from the organic and mineral layers of two severely burned sites and an unburned control site over the span of two years following the fire. Microbial community composition was evaluated by principal component analysis and multivariate analysis of variance of molecular fingerprint data for bacterial, archaeal, and fungal-specific amplicons from denaturing gradient gel electrophoresis. The bacterial communities in the samples collected from 2 and 5 months following the fire clustered separately from those collected 13 and 17 months post-fire in two-dimensional space, indicating that the soil bacterial community structure changed with time following the fire. Deeper evaluation of the bacterial, archaeal, and fungal community patterns revealed that even though there were common bands between the unburned and the severely burned samples, the community structure of the samples from the unburned site grouped separately from those of the severely burned sites collected 2, 13, and 25 months post-fire. Generally, the microbial community composition in the unburned samples did not change significantly over two years. These data support the hypothesis that the soil microbial community was selected by both the direct and indirect effects associated with the wildfire in the initial two years after the perturbation. Rather than return to the predisturbance state, the soil microbial communities may reflect an alternate state two years following the fire.
Author: Inga Parker La Puma Publisher: ISBN: Category : Fire ecology Languages : en Pages : 182
Book Description
Effects of urban land-uses have long term implications for the structure and function of natural ecosystems that may extend far beyond the land-use itself. Specifically, natural disturbance and succession in forest ecosystems have been highly altered by human-caused land-use and fire frequency changes. Changes to forest community structure and composition can affect the long-term sustainability of areas such as the New Jersey Pinelands, a fire-dependent ecosystem. By combining historic maps of fire frequency and land-use change, I assessed the effects of human development patterns on fire and forest composition in the Pinelands. These assessments showed lower fire frequency and higher transitions from pine to oak forest cover in close geographic proximity to altered land. Additionally, I investigated our ability to detect the effects of fire on water quality measures using data from gauged watersheds. No significant effects of fire could be determined due to a lack of water quality data associated with wildfires in space and time. I used a spatially-explicit forest disturbance and succession model to investigate how increasing levels of altered land and changing fire regimes may affect forest composition in the future. Additionally, I added climate change to disturbance and succession modeling to incorporate this additional forcing on fire and forest composition. These scenarios showed an overwhelming trend toward oak dominated forest within 100 years, except in the unique pine plains area, where pine species still dominated. The potential of this type of dramatic shift from pine to oak cover represents a radical departure from current forest composition and needs to be addressed by managers of the Pinelands National Reserve in order to maintain the essential Pinelands landscape. Modeling the potential influences of current and future altered land as well as changes in fire regimes in our study area elucidates the degree to which fire and climate disturbances may alter forest composition.
Author: Paulo Pereira Publisher: CSIRO PUBLISHING ISBN: 1486308155 Category : Science Languages : en Pages : 721
Book Description
Wildland fires are occurring more frequently and affecting more of Earth's surface than ever before. These fires affect the properties of soils and the processes by which they form, but the nature of these impacts has not been well understood. Given that healthy soil is necessary to sustain biodiversity, ecosystems and agriculture, the impact of fire on soil is a vital field of research. Fire Effects on Soil Properties brings together current research on the effects of fire on the physical, biological and chemical properties of soil. Written by over 60 international experts in the field, it includes examples from fire-prone areas across the world, dealing with ash, meso and macrofauna, smouldering fires, recurrent fires and management of fire-affected soils. It also describes current best practice methodologies for research and monitoring of fire effects and new methodologies for future research. This is the first time information on this topic has been presented in a single volume and the book will be an important reference for students, practitioners, managers and academics interested in the effects of fire on ecosystems, including soil scientists, geologists, forestry researchers and environmentalists.
Author: Cassie Lenae Hebel Publisher: ISBN: Category : Endemic plants Languages : en Pages : 126
Book Description
Fire suppression in the last several decades has resulted in unprecedented accumulations of organic matter on the landscape, leading to an increase in large, intense wildfires. This study investigated the soil microbial community (using phospholipid fatty acid analysis) across recently burned forests on the eastern slope of the Cascade Range in Oregon to examine the effects this belowground community has on the growth of native and non-native plant species in severely burned "red" soil and in less severely burned "black" soil. Long duration, smoldering conditions creating red soils drastically altered both soil nutrients and microbial community structure. Changes in soil properties and biota affected plant growth in a controlled growth chamber, as well as vegetative colonization on red soil plots in natural field conditions. Differential growth was observed between native and non-native plant species when grown in soil from the two burn severities. Native plant growth did not differ between black and red soil, while non-native plants showed reduced growth in red soil. Although it previously had been reported that fire increased the likelihood of invasion by non-native plant species in a burn area, these results do not support the notion that red soil conditions are more susceptible than moderately burned soil to non-native, invasive plant species colonization. While many factors in addition to mycorrhizal colonization and burn severity influence plant growth, such as soil nutrient availability, our results suggest that a variety of strategies allow plants to grow in disturbed environments. Continued monitoring of microbial communities and re-vegetation in red soil sites could further our understanding of the length of post-fire recovery time of severely burned red soil.
Author: Jennifer Suzanne Hooke Publisher: ISBN: Category : Fire ecology Languages : en Pages : 210
Book Description
The Normalized Burn Ratio and Composite Burn Index were used to classify burn severity in three sites that experienced lightning-ignited wildfire in the year 2000. The effect of burn severity (unburned, low, moderate, and high severity classes) was investigated on vegetation and soil microbial community composition. Vegetation communities showed a strong response to burn severity, with distinct communities associated with each burn severity class. Indicator Species Analysis was used to identify plant species associated with each burn severity class; one interesting result from ISA was that trembling aspen (Populus tremuloides) seedlings emerged as an indicator of the moderate severity class. Species richness and tree seedling density differed among burn severity classes. Soil microbial communities were analyzed using Phospholipid Fatty Acid analysis and showed moderate variation among burn severity classes and study sites. Total soil carbon and nitrogen did not differ with burn severity. The C:N ratio, total soil S, and soil pH differed significantly among burn severity classes. While the effect of burn severity is pronounced upon vegetation three years post-fire, effects on soil microbial communities are less evident. This could be attributed to the insulating properties of soils, the time elapsed after fire, or it could be an artifact of the sampling technique.
Author: Jaron Adkins Publisher: ISBN: Category : Electronic dissertations Languages : en Pages : 262
Book Description
Forest ecosystems are important reservoirs for long term carbon (C) storage. Forests of the western United States account for 20-40% of total U.S. carbon C sequestration, and nearly half of the total C in these forests is stored in soil. However, many forests in the western U.S are experiencing wildfire conditions that diverge from historical fire regimes. Prior to Euro-American settlement, California's mixed-conifer forests typically experienced frequent surface fires of low to moderate burn severity, but, due to the combined effects of altered forest structure and climate change, now experience fires that are larger and more severe than historical conditions. Fires have numerous direct and indirect effects on the soil biological, chemical, and physical characteristics that influence the soil C cycle. Understanding how altered soil characteristics influence the cycling and persistence of soil C, and how they vary with severity, is important for managing forests for C storage and for predicting fire-climate feedbacks. My dissertation work incorporates observational and manipulative experiments to understand the direct and indirect effects of burn severity on soil C cycling and microbial communities over the short to intermediate term, with a particular focus on the distribution of soil C between active and slow cycling pools. Soil C can be conceptualized as discrete pools of variable persistence in soil. The active C pool is quickly decomposed, contributing to the return of CO2 to the atmosphere, whereas the non-active C pool is more stable and contributes to long term C storage. I leveraged a burn severity gradient resulting from a wildfire in a California mixed-conifer forest to determine the structure and kinetics of these C pools at an intermediate time point in post-fire recovery (i.e. three years). I found that the size of the non-active C pool was smaller in burned areas than unburned areas, and the kinetic rate of the non-active C pool was negatively related to burn severity. I also characterized the soil microbial communities across this severity gradient and identified the environmental characteristics responsible for differences. I found that fungal-to-bacterial ratio and oligotroph-to-copiotroph bacteria ratio decreased with burn severity, and these effects were driven by differences in live and dead tree basal area, soil nutrients, and pH. Leveraging another burn severity gradient, I then determined whether differences in microbial communities and soil C pools were related one-year post-fire in a mixed-conifer forest. I again found lower non-active C pool kinetic rates, and higher abundances of copiotrophic bacteria in burned compared to unburned areas. Differences in soil C pool kinetics were related to tree basal area, soil nutrients, and bacterial communities.I determined the short-term impacts of fire on soil C pools and cycling using lab experiments in which I manipulated soil heating intensity and pyrogenic organic matter (PyOM) additions. I found that high intensity soil heating can decrease microbial biomass C (MBC) accumulation, whereas PyOM had minimal effects on MBC in the short-term. Finally, I found that the size of the active C pool increased with soil heating intensity, while the kinetic rate of the non-active C pool decreased; PyOM primarily increased the size of the non-active C pool. Taken as a whole, my research suggests that fire induces short-term soil C losses by increasing the size of the active C pool, but, over the intermediate-term, residual soil C is more persistent. Fire severity is predicted to increase globally throughout the 21st century, and my research contributes to understanding how forest C storage will be affected by disrupted wildfire regimes.
Author: Ralph E. J. Boerner Publisher: ISBN: Category : Forest fires Languages : en Pages : 11
Book Description
The New Jersey Pine Barrens mosaic is made up of species exhibiting numerous adaptations to wildfire, including the dominants, Pinus rigida and several species of Quercus. To evaluate community change and recovery from two disturbance intensities (wildfire and prescribed burning), a site unburned for 53 years, two sites burned by wildfire in 1977 and 1978 and two sites burned by prescription in 1977 and 1979 were examined for species composition, horizontal and vertical structure and biomass relations.
Author: Robyn Ann Mikita
Author: Robyn Ann Mikita
Author: Inga Parker La Puma
Author: Paulo Pereira
Author: A. H. Johnson
Author: Cassie Lenae Hebel
Author: Barbara Fassuliotis Rogers
Author: Jennifer Suzanne Hooke
Author: Aida E. Jiménez Esquilín
Author: Jaron Adkins
Author: Ralph E. J. Boerner