Download or read book The Seasonal Influence of Saltmarsh Plants Salicornia Virginica and Scirpus Robustus on Methylmercury Production and Degradation Over Small Spatial Scales in South San Francisco Bay written by Le Hue Kieu and published by . This book was released on 2004 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury Uptake by a Dominant Plant Species in San Francisco Bay Tidal Marshes Salicornia Virginica written by Jenny Jensen and published by . This book was released on 2007 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Impacts of Extreme Drought Eutrophication and Plant Invasion on Salt Marshes and Blue Carbon written by Megan Amanda Kelso and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Coastal salt marshes are ecologically rich, productive systems that provide many benefits including flood protection, water filtration, and habitat for coastal fish, invertebrates, and shorebirds. In addition, they are one of the most effective natural systems at sequestering carbon, storing it three times as densely as most forest systems per unit area. These valuable ecosystems are increasingly threatened by anthropogenic stressors such as invasive species, eutrophication, and climate change. Each of these stressors can have large independent impacts on ecosystems and may also have important interactive effects. In this dissertation, I explore the interacting effects of extreme drought associated with climate change, eutrophication, and invasion by an aggressive non-native plant called Lepidium latifolium on tidal salt marshes and their ability to sequester carbon. In chapter 1, my collaborators and I explored how the combined stress of extreme drought and elevated nutrients altered invasion dynamics of L. latifolium in tidal salt marshes of San Francisco Bay, CA, USA. From 2012-2015, California experienced an unprecedented drought that stressed tidal salt marsh ecosystems. In a three-year field experiment from 2014 to 2016, we tracked the effects of this extreme drought on L. latifolium invasion using field experiments to test how nutrient addition altered invasion dynamics at four salt marsh sites along a salinity gradient in San Francisco Bay. We documented a dramatic die-back of invasive L. latifolium during the extreme drought, including large reductions in stem density (52%-100%) and height (17%-47%) that were more severe at low salinity sites than high salinity sites. We found nutrient addition lessened the effect of drought on L. latifolium stem density, but not height. In native salt marsh plots, extreme drought reduced native plant percent cover (4%-24%), but nutrient addition strongly mitigated this impact. Interestingly, we found native plants in areas invaded by L. latifolium did not suffer reductions in percent cover due to drought, perhaps because they were simultaneously benefitting from the die-back of the invader. Further, native plant percent cover actually increased during the drought in plots that were both invaded by L. latifolium and received nutrients. These results indicate extreme drought is an important driver of change in salt marsh plant communities and may impede the invasion and spread of L. latifolium. Further, nutrient loading appears to help both native and invasive plants cope with extreme drought stress. In chapter 2, we examined the physical mechanisms and temporal scale underlying the dramatic die-back of L. latifolium documented in chapter 1. Extreme drought affects estuarine tidal salt marshes both by reducing local rainfall and by raising estuarine salinity through reduced fresh-water inflows. We tested the impact of local rainfall on L. latifolium by experimentally manipulating rainfall for one year in plots at a salt marsh in south San Francisco Bay. Surprisingly, we did not detect a significant impact of local rainfall on density of the invader, despite diverting 100% of the rainfall that would have fallen into experimental plots during the rainy season (January to mid-May). Next, we explored the relationship between bay salinity and invasion using eight years of monthly water column salinity data and five years of L. latifolium density field data at three salt marsh sites. We found a significant time-lagged (three years) effect of bay salinity on L. latifolium density across our three sites, with high salinities preceding reductions in L. latifolium densities and low salinities preceding increases. The most dramatic change in stem density, a 54% reduction in 2015, was preceded by a salinity increase of 43% from 2011 to 2012. Our finding that water column salinity was a major driver of L. latifolium invasion dynamics suggests sea level rise, like extreme drought, may hinder L. latifolium invasion, since rising sea levels will also raise estuarine salinities. Further, our study highlights the importance of temporal lags in climate change impacts on biological invasions, which has received very little study to date. In chapter 3, we examine the effects of L. latifolium invasion and eutrophication on the valuable ecosystem service of carbon storage provided by coastal salt marshes, known as “blue carbon” storage. Specifically, we measured standing stock of carbon and rates of decomposition, an important underlying process driving future rates of carbon storage. We found invasion by L. latifolium overall decreased blue carbon, a surprising result that contradicts the general assumption that invasive plants store more carbon than native communities. We identified a synergistic interaction between invasion and nutrient addition on rates of below-ground decomposition, where nutrient addition amplified the accelerating effect of invasion on below-ground decomposition. We found nutrient addition increased carbon in above-ground and below-ground biomass. Our results demonstrate that anthropogenic stressors can alter blue carbon in independent and interactive ways. Taking a multi-stressor approach to studying blue carbon ecosystems will improve predictions of the permanence of blue carbon storage and might explain some of the observed variability in carbon storage among sites, two of the largest technical hurdles impeding the development of comprehensive blue carbon policy. Coastal wetland ecosystems are under threat from multiple concurrent stressors and understanding their combined impacts on these ecosystems and the valuable carbon storage service they provide is critical for effective management and policy development.
Download or read book Variation in Response to a Continuum of Stress and Disturbance in a Salt Marsh Plant Assemblage written by Stuart Keating Allison and published by . This book was released on 1991 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Impact of Salt Marsh Chemistry on Spartina and Salicornia Distribution Indian Island Humboldt Bay California written by Linda Carol Newby and published by . This book was released on 1980 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Inter and Intraspecific Variation in Carbon and Nutrient Pools of Salt Marsh Plants written by Tracy Elsey-Quirk and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study examined both inter- and intraspecific variation of four dominant salt marsh macrophytes, a high marsh shrub, Baccharis halimifolia, a high marsh rush, Juncus roemerianus, a mid-marsh grass, Spartina patens, and the low marsh grass that is ubiquitous in wetlands along the Atlantic and Gulf coasts of the United States, short-form S. alterniflora. Chapter One evaluates the seasonal C pool dynamics of the four species including the seasonal allocation of above- and belowground C pools, C pool loss through decomposition, and soil C concentration in a wetland fringing Little Assawoman Bay, one of Delaware's Coastal Bays. To determine whether the rate of vertical accretion and organic matter accumulation differed between the low, S. alterniflora and high, J. roemerianus zones, soil cores from the two zones were used to measure 137 Cs and 210 Pb activity. Total plant C pools of the mid- and low marsh grass species, Spartina patens (4360 g C m -2) and Spartina alterniflora (4197 g C m -2), were similar and almost two and three times larger than total pools of Juncus roemerianus (2508 g C m -2) and Baccharis halimifolia (1490 g C m -2), respectively. Moving from the high to low marsh zones, the C pool shifted from primarily aboveground to belowground. Baccharis had the greatest aboveground C storage (1140 g m -2) and the slowest rate of C loss. Chapter Two examines interspecific variation in N pool dynamics in the four species including seasonal allocation of N pools above- and belowground, N loss through decomposition, N resorption efficiency, and soil N concentration. The seasonal fluctuation in the total N pools of the herbaceous species was due to belowground N pool dynamics, particularly fine root and dead large and small-sized macroorganic matter fluxes. Comparisons among the species revealed that the location, magnitude and timing of N storage and dispersal differed, which is important in the context of how species will shift in response to environmental change. Chapter Three describes the above- and belowground species associations in the fringing wetland and whether or not species shifts have occurred. Accurate productivity measurements in fringing wetlands may be dependent on species-specific organic matter separation, particularly belowground. Vegetation change in salt marshes may also become apparent when comparing above- and belowground species-specific live and dead organic matter. We surveyed species richness, frequency, and percent cover and measured above- and belowground biomass in three vegetation zones. Our study illustrates the importance of species-specific belowground biomass estimates to provide evidence of species shifts in both the low and high marsh zones. Chapter four examines intraspecific variation in morphological characteristics and carbon, nutrient, and mineral concentration and allocation within B. halimifolia, J. roemerianus, S. patens, and S. alterniflora. Ecotypic variation in morphology and composition and allocation of C, nutrients, and minerals in wetland plants may influence ecosystem functions such as the deposition and trapping of sediments, detritus production, secondary productivity, the cycling and storage of organic and inorganic nutrients, belowground organic matter production, and long-term C storage. We examined the expression of morphological traits and C, nutrient, and mineral composition and allocation among southern ecotypes, a tissue-culture regenerant, and a native mid-Atlantic ecotype for each of four salt marsh species after two growing seasons within natural stands in a mid-Atlantic salt marsh. Overall, we found that the expression of phenotypic variation was greatest in the low marsh, Spartina alterniflora than in the higher marsh species likely due to both the greater spatial variation in elevation and soil conditions in the higher marsh and potentially a lower tolerance of higher marsh species to environmental stress. The differences that we found among ecotypes have important implications for enhancing and developing ecosystem processes in restoration and creation projects. Chapter Five characterizes carbon pool dynamics of the salt marsh species, J. roemerianus, S. patens, and S. alterniflora using a STELLA model. The model was developed to examine the relationships between C pools and fluxes within species, to simultaneously compare the timing and magnitude of seasonal fluxes of C of each of the three species within a square meter, and to examine how changes to model parameters influence C pool dynamics and the accumulation of C belowground. (Abstract shortened by UMI.).
Download or read book The Role of Biotic and Abiotic Processes in the Zonation of Salt Marsh Plants in the Nueces River Delta Texas written by Michael Kevin Rasser and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Salt marshes provide critical ecosystem services, such as shoreline stabilization, biogeochemical cycling and habitat for wildlife, to much of the world's population living on the coasts. Emergent vascular plants are a critical component of these ecosystems. This study was a comprehensive effort to gain a better understanding of the ecology of salt marsh plants in the Nueces River delta on the south Texas coast. This knowledge is essential to understand the potential anthropogenic impacts on salt marshes, including sea-level rise, global warming, reduced freshwater inflow and coastal erosion. A combination of remote sensing analysis, field studies and experiments were used to allow analysis across spatial scales ranging from landscape patterns of vegetation to leaf level measurements of the dominant species. A novel method of image classification was developed using high-resolution multi-spectral imagery integrated with ancillary data to map the major plant communities at a landscape scale. This included a high marsh assemblage composed primarily of Spartina spartinae and a low marsh community dominated by Borrichia frutescens and Salicornia virginica. Geospatial analysis determined that the location of these plant communities was related to the distance from the tidal creek network and elevation. The B. frutescens and S. virginica assemblage was more abundant at lower elevations along the waters edge, making it vulnerable to loss from shoreline erosion. At a finer spatial scale, gradient analysis was utilized to examine the relationship between elevation, which creates environmental gradients in salt marshes, and species distribution. I discovered that elevation differences of less than 5 cm can influence both individual species and plant community distribution. One interesting finding was that the two dominant species, B. frutescens and S. virginica, share similar responses along an elevation gradient yet are observed growing in monotypic adjacent zones. I constructed a large reciprocal transplant experiment, using 160 plants at 4 sites throughout the marsh, to determine what causes the zonation between these two species. The results of this study found that S. virginica fared well wherever it was transplanted but was a weak competitor. B. frutescens survival was significantly lower in the S. virginica zone than in its own zone suggesting that abiotic factors are important in determining the zonation of this species. However, high spatial and temporal variability existed in environmental parameters such as salinity. This variability may have been caused by the semi-arid climate and irregular flooding typical in the Nueces Marsh. Therefore, I utilized a greenhouse experiment to directly test the importance of the two dominant physical factors in salt marshes, flooding and salinity. The results found that for B. frutescens the effects of flooding were not significant, however salinity at 30% reduced growth. Salinity did not influence growth of S. virginica. The greater ability of S. virginica to tolerate salinity stress has important implications because reduced freshwater inflow or climate change can increase porewater salinity, thus favoring the expansion of S. virginica, and altering the plant community structure.
Download or read book Mercury in the Environment written by and published by . This book was released on 2000 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Impacts of Construction Activities in Wetlands of the United States written by Rezneat M. Darnell and published by . This book was released on 1976 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tidal Marsh Restoration written by Charles T. Roman and published by Island Press. This book was released on 2012-08-07 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many coastal tidal marshes have been significantly degraded by roadways and other projects that restrict tidal flows, limiting their ability to provide vital ecosystem services including support of fish and wildlife populations, flood protection, water quality maintenance, and open space. Tidal Marsh Restoration provides the scientific foundation and practical guidance necessary for coastal zone stewards to initiate salt marsh tidal restoration programs. The book compiles, synthesizes, and interprets the current state of knowledge on the science and practice of salt marsh restoration, bringing together leaders across a range of disciplines in the sciences (hydrology, soils, vegetation, zoology), engineering (hydraulics, modeling), and public policy, with coastal managers who offer an abundance of practical insight and guidance on the development of programs. The work presents in-depth information from New England and Atlantic Canada, where the practice of restoring tidal flow to salt marshes has been ongoing for decades, and shows how that experience can inform restoration efforts around the world. Students and researchers involved in restoration science will find the technical syntheses, presentation of new concepts, and identification of research needs to be especially useful as they formulate research and monitoring questions, and interpret research findings. Tidal Marsh Restoration is an essential work for managers, planners, regulators, environmental and engineering consultants, and others engaged in planning, designing, and implementing projects or programs aimed at restoring tidal flow to tide-restricted or diked salt marshes.
Download or read book Wigeongrass Ruppia Maritima L written by Harold A. Kantrud and published by . This book was released on 1991 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book National Wildlife Refuge System Improvement Act of 1997 written by and published by . This book was released on 1999 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecology Conservation and Restoration of Tidal Marshes written by Arnas Palaima and published by Univ of California Press. This book was released on 2012-09-08 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The San Francisco Bay, the biggest estuary on the west coast of North America, was once surrounded by an almost unbroken chain of tidal wetlands, a fecund sieve of ecosystems connecting the land and the Bay. Today, most of these wetlands have disappeared under the demands of coastal development, and those that remain cling precariously to a drastically altered coastline. This volume is a collaborative effort of nearly 40 scholars in which the wealth of scientific knowledge available on tidal wetlands of the San Francisco Estuary is summarized and integrated. This book addresses issues of taxonomy, geomorphology, toxicology, the impact of climate change, ecosystem services, public policy, and conservation, and it is an essential resource for ecologists, environmental scientists, coastal policymakers, and researchers interested in estuaries and conserving and restoring coastal wetlands around the world.
Download or read book The Ecological Condition of Estuaries in the Gulf of Mexico written by and published by . This book was released on 1999 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Safety Evaluation of Existing Dams written by and published by . This book was released on 1983 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Annual Report of Progress written by Transit Cooperative Research Program and published by . This book was released on 1872 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cascade Impactor written by James P. Lodge and published by Amer Industrial Hygiene Assn. This book was released on 1986 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
