Download or read book Patterns and Processes of Saltmarsh Area Change at Three Spatial Scales written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Patterns and Processes of Saltmarsh Area Change at Three Spatial Scales written by Cai Ladd and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Patterns and Processes of Saltmarsharea Change at Three Spatial Scales written by Cai J. T. Ladd and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecosystems around the globe are being degraded by anthropogenic activity. Coastalecosystems are considered especially vulnerable given that human populations areconcentrated at the coast. Extensive areas of saltmarsh habitat have already been lost to landreclamation, and the continued existence of natural marsh systems is in question.Understanding how saltmarsh plants interact within a changing coastal environment is seen asa vital step in protecting remaining habitat and delivering successful restoration. This thesisexamines patterns of saltmarsh change across Great Britain (GB), and the biological andenvironmental drivers responsible for change, in order to better understand marsh persistence.Studies have tended to assess marsh persistence based on their capacity to grow verticallywith sea level rise. Long-term horizontal marsh dynamics are often overlooked. Chapter 2examines 100 years of saltmarsh area change across GB and found that sea level rise andsediment supply determined whether saltmarshes expanded or eroded. All marshes werekeeping pace with sea level rise, highlighting the importance of considering horizontaldynamics in long-term marsh change.Identifying the limits on horizontal saltmarsh growth onto tidal flats has been valuable inassessing potential impacts of coastal change on open-coast marsh systems, however little workhas been done on identifying limits of marsh extent within estuaries. Chapter 3 examinessaltmarsh extent change between 1948 and 2013 in three sheltered estuaries along western GB,and shows that changes in the position of tidal channels limited marsh extent. Channelsperiodically migrated across the estuary causing marsh erosion. On the opposite bank, marshestended to expand, indicating the capacity of marshes to cycle between phases of expansion anderosion retaining a dynamic persistence within estuaries.Horizontal erosion of saltmarsh creeks causes vegetated marsh debris to accumulate at thecreek base. Indications are that these deposits limit further erosion and promote recoverythrough trapping sediment if they persist. However, biotic and abiotic controls on debrislongevity are unclear. Chapter 4 examines monthly creek change over a year and shows thatfailed bank debris with high root content slow debris erosion rates, thereby promoting sedimenttrapping and recovery. Thus, plant growth plays an important role on saltmarsh stability.By investigating marsh change over different spatio-temporal scales, a picture emerges ofhow biological and environmental drivers collectively influence change in saltmarsh extent.This offers important insight into how management interventions could target the drivers ofmarsh change at each scale in order to build marsh resilience, and is discussed in chapter 5.

Download or read book Concepts and Controversies in Tidal Marsh Ecology written by M.P. Weinstein and published by Springer Science & Business Media. This book was released on 2000-10-31 with total page 862 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tidal salt marshes are viewed as critical habitats for the production of fish and shellfish. As a result, considerable legislation has been promulgated to conserve and protect these habitats, and much of it is in effect today. The relatively young science of ecological engineering has also emerged, and there are now attempts to reverse centuries-old losses by encouraging sound wetland restoration practices. Today, tens of thousands of hectares of degraded or isolated coastal wetlands are being restored worldwide. Whether restored wetlands reach functional equivalency to `natural' systems is a subject of heated debate. Equally debatable is the paradigm that depicts tidal salt marshes as the `great engine' that drives much of the secondary production in coastal waters. This view was questioned in the early 1980s by investigators who noted that total carbon export, on the order of 100 to 200 g m-2 y-1 was of much lower magnitude than originally thought. These authors also recognized that some marshes were either net importers of carbon, or showed no net exchange. Thus, the notion of `outwelling' has become but a single element in an evolving view of marsh function and the link between primary and secondary production. The `revisionist' movement was launched in 1979 when stable isotopic ratios of macrophytes and animal tissues were found to be `mismatched'. Some eighteen years later, the view of marsh function is still undergoing additional modification, and we are slowly unraveling the complexities of biogeochemical cycles, nutrient exchange, and the links between primary producers and the marsh/estuary fauna. Yet, since Teal's seminal paper nearly forty years ago, we are not much closer to understanding how marshes work. If anything, we have learned that the story is far more complicated than originally thought. Despite more than four decades of intense research, we do not yet know how salt marshes function as essential habitat, nor do we know the relative contributions to secondary production, both in situ or in the open waters of the estuary. The theme of this Symposium was to review the status of salt marsh research and revisit the existing paradigm(s) for salt marsh function. Challenge questions were designed to meet the controversy head on: Do marshes support the production of marine transient species? If so, how? Are any of these species marsh obligates? How much of the production takes place in situ versus in open waters of the estuary/coastal zone? Sessions were devoted to reviews of landmark studies, or current findings that advance our knowledge of salt marsh function. A day was also devoted to ecological engineering and wetland restoration papers addressing state-of-the-art methodology and specific case histories. Several challenge papers arguing for and against our ability to restore functional salt marshes led off each session. This volume is intended to serve as a synthesis of our current understanding of the ecological role of salt marshes, and will, it is hoped, pave the way for a new generation of research.

Download or read book Spatial and Temporal Dynamics of Salt Marsh Vegetation Across Scales written by Daehyun Kim and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Biogeographic patterns across a landscape are developed by the interplay of environmental processes operating at different spatial and temporal scales. This research investigated dynamics of salt marsh vegetation on the Skallingen salt marsh in Denmark responding to environmental variations at large, medium, and fine scales along both spatial and temporal spectrums. At the broad scale, this research addressed the importance of wind-induced rise of the sea surface in such biogeographic changes. A new hypothetical chain was suggested: recent trends in the North Atlantic Oscillation index toward its positive phase have led to increased storminess and wind tides on the ocean surface, resulting in increased frequency, duration, and magnitude of submergence and, hence, waterlogging of marsh soils and plants, which has retarded ecological succession. At the mid-scale, spatial patterns of vegetation and environmental factors were examined across tidal creeks. Sites closer to tidal creeks, compared to marsh interiors, were characterized by the dominance of later-successional species, higher bulk density, and lower nutrient contents and electrical conductivity. This finding implies that locations near creeks have experienced a better drainage condition than the inner marshes, which eventually facilitated the establishment of later-successional plants that are intolerant to physical stress. At the micro-scale, this research examined how the extent and mode of facilitation and competition vary for different combinations of plant species along physical gradients. Both positive and negative relationships were spatially manifested to a greater degree on the low marsh than on the mid marsh. This insight extends our current knowledge of scale-dependent interactions beyond pioneer zones to higher zones. On the low marsh, different types of bivariate point pattern (i.e., clustered, random, and regular) were observed for different combinations of species even at similar spatial scales. This finding implies that it is difficult to generalize at which scales competition and facilitation occur. To conclude, this research stresses the need for a holistic approach in future investigations of salt marsh biogeography. For example, based on results of this current research, it would be meaningful to develop a comprehensive simulation model that incorporates salt marsh ecology, geomorphology, and hydrology observed across scales.

Download or read book Handbook of Halophytes written by Marius-Nicusor Grigore and published by Springer. This book was released on 2021-05-19 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Highlights the potential of biosaline agriculture in a changing environment Covers all important topics related to halophyte biology including biochemistry, genetics and genomics Provides information on potential use of halophytes Each topic is explained in detail and examined from various angles More than 100 contributions by international experts

Download or read book Coastal Wetlands written by Gerardo M.E. Perillo and published by Elsevier. This book was released on 2009-01-18 with total page 975 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coastal wetlands are under a great deal of pressure from the dual forces of rising sea level and the intervention of human populations both along the estuary and in the river catchment. Direct impacts include the destruction or degradation of wetlands from land reclamation and infrastructures. Indirect impacts derive from the discharge of pollutants, changes in river flows and sediment supplies, land clearing, and dam operations. As sea level rises, coastal wetlands in most areas of the world migrate landward to occupy former uplands. The competition of these lands from human development is intensifying, making the landward migration impossible in many cases. This book provides an understanding of the functioning of coastal ecosystems and the ecological services that they provide, and suggestions for their management. In this book a CD is included containing color figures of wetlands and estuaries in different parts of the world. - Includes a CD containing color figures of wetlands and estuaries in different parts of the world.

Download or read book Towns Ecology and the Land written by Richard T. T. Forman and published by Cambridge University Press. This book was released on 2019-02-07 with total page 637 pages. Available in PDF, EPUB and Kindle. Book excerpt: A pioneering book highlighting the dynamic environmental dimensions of towns and villages and spatial connections with surrounding land.

Download or read book Salt Marshes written by Duncan M. FitzGerald and published by Cambridge University Press. This book was released on 2021-04-22 with total page 499 pages. Available in PDF, EPUB and Kindle. Book excerpt: A multidisciplinary review of salt marshes, describing how they function and respond to external pressures such as sea-level rise.

Download or read book Seascape Ecology written by Simon J. Pittman and published by John Wiley & Sons. This book was released on 2017-10-30 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seascape Ecology provides a comprehensive look at the state-of-the-science in the application of landscape ecology to the seas and provides guidance for future research priorities. The first book devoted exclusively to this rapidly emerging and increasingly important discipline, it is comprised of contributions from researchers at the forefront of seascape ecology working around the world. It presents the principles, concepts, methodology, and techniques informing seascape ecology and reports on the latest developments in the application of the approach to marine ecology and management. A growing number of marine scientists, geographers, and marine managers are asking questions about the marine environment that are best addressed with a landscape ecology perspective. Seascape Ecology represents the first serious effort to fill the gap in the literature on the subject. Key topics and features of interest include: The origins and history of seascape ecology and various approaches to spatial patterning in the sea The links between seascape patterns and ecological processes, with special attention paid to the roles played by seagrasses and salt marshes and animal movements through seascapes Human influences on seascape ecology—includes models for assessing human-seascape interactions A special epilogue in which three eminent scientists who have been instrumental in shaping the course of landscape ecology offer their insights and perspectives Seascape Ecology is a must-read for researchers and professionals in an array of disciplines, including marine biology, environmental science, geosciences, marine and coastal management, and environmental protection. It is also an excellent supplementary text for university courses in those fields.

Download or read book Salt Marshes and Salt Deserts of the World written by Valentine Jackson Chapman and published by . This book was released on 1960 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Halophytes for Food Security in Dry Lands written by Muhammad Ajmal Khan and published by Academic Press. This book was released on 2015-09-15 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Halophytes for Food Security in Dry Lands addresses the concerns surrounding global food scarcity, especially focusing on those living in arid and dry lands The book touches on food crises in dry regions of the world and proposes halophytes as an alternate source of consumption for such areas. Halophytes, those plants that thrive in saline soil and provide either food source options themselves, or positively enhance an eco-system's ability to produce food, and are thus an important and increasingly recognized option for addressing the needs of the nearly 1/6 of the world's population that lives in these arid and semi-arid climates. Including presentations from the 2014 International Conference on Halophytes for Food Security in Dry Lands, this book features insights from the leading researchers in the subject. It is a valuable resource that includes information on the nutritional value of halophytes, their genetic basis and potential enhancement, adaption of halophytes, and lessons learned thus far. - Provides comprehensive coverage of the importance and utilization of halophytes to compensate the demand of food in whole world especially in the dry regions - Contains insights from ecological to molecular fields - Includes edible halophytes as well as those that enhance food-producing eco-systems - Presents information for improving abiotic stress tolerance in plants

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 Louisiana Coastal Area Ecosystem Restoration Study written by and published by . This book was released on 2004 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spatial Analysis of Coastal Environments written by Sarah M. Hamylton and published by Cambridge University Press. This book was released on 2017-04-13 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the spatial analytical tools needed to map, monitor and explain or predict coastal features, with accompanying online exercises.

Download or read book Moving Forward After Hurricanes Katrina and Rita written by United States. Congress. Senate. Committee on Environment and Public Works and published by . This book was released on 2011 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Groundwater Vegetation Atmosphere Interactions in an Intertidal Salt Marsh written by Kevan Bauer Moffett and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A large fraction of coastal wetlands worldwide have been severely impacted by development, resulting in among the highest losses of any wetland type. Necessary improvements in restoration and management of coastal wetlands require a better scientific understanding of the underlying plant-water interactions, or ecohydrology. This research developed a new conceptual model of intertidal salt marsh ecohydrology to define the relative roles of: tidal flooding, groundwater flow, vegetation zonation, and plant water uptake. Spatial and temporal variations in plant-water interactions were observed over three years at a field site in the Palo Alto Baylands, California. Three-dimensional numerical simulations of the coupled surface water and unsaturated groundwater flow and evapotranspiration (ET) at the site were used to explore the links between marsh vegetation and hydrology. /// Vegetation zonation is one of the most distinctive properties of salt marshes, yet had not been combined with physics-based hydrologic analysis prior to this research. Statistical analysis showed that vegetation zones at the field site were not correlated with traditional proxies for hydrologic influences such as elevation and distance-to-channel. Vegetation zonation was strongly correlated with a metric describing the spatial patterns of tidally-induced changes in salt marsh soil saturation and salinity. This metric was developed based on time-lapse imaging of bulk soil electrical conductivity and a new geophysical analysis method, Quantitative Differential Electromagnetic Induction imaging (Q-DEMI). /// Spatial variations in vegetation water use within and among vegetation zones were investigated in detail using centimeter-resolution thermal infrared (TIR) remote sensing. Well-established latent heat models were adapted to use spatially-variable canopy stomatal resistances. The detailed stomatal resistance maps were determined from the TIR data in a biophysically realistic manner by a new method. In principle, the stomatal resistance mapping method is applicable at scales from leaves (such as in this study) to landscapes. /// The dynamics of plant-water interactions originating at the leaf scale were also detectable in marsh-scale eddy covariance and meteorological field data. Alternating daytime tidal flooding and exposure shifted the marsh surface energy balance: from similar to a well-watered lawn during flooding, to similar to a sparse crop during exposure. The net ecosystem exchange of carbon dioxide was also temporarily suppressed in proportion to flood depth and duration, further indicating close plant-water coupling in the intertidal salt marsh environment. /// These spatial and temporal plant-water interactions occur within a larger context governed by the tidal regime and coastal groundwater flow. Continuous measurements of groundwater potential characterized marsh groundwater dynamics and provided evidence of sediment heterogeneity at the field site. In three dimensional, coupled groundwater-surface water simulations, the sediment heterogeneity affected both the balance between creek bank and interior marsh hydrologic processes and the spatial distribution of groundwater-surface water exchange. In the field, similar groundwater discharge zones were located in the tidal channels by fiber-optic distributed temperature sensing (DTS). The DTS data also provided the first description of the salt marsh benthic thermal regime, a system co-dominated by groundwater discharge and an ephemeral "tidal thermal blanket." /// Spatial variability in ET and rooting depth due to vegetation zonation were incorporated into a numerical model to represent the ecohydrologic system. The zonally-distributed ET and rooting depths caused notable spatial variations in hydrologic conditions in the marsh root zone, including significant variations in unsaturated pressure head and soil saturation. Modest control of salt marsh water table depth by vegetation following flooding tides was simulated throughout the field site, in accord with the prevailing conceptual model of salt marsh plant-water interactions. The simulations also suggested four additional classes of ecohydrologic dynamics apparent under conditions of prolonged marsh exposure. The four new classes of ecohydrological behavior were distinguished by combinations of relatively high or low soil permeability and high or low ET rate. Together, patterns in vegetation and soil permeability thus created distinctive "ecohydrological zones." In some cases, the contrast among such ecohydrological zones caused upward and downward groundwater flow regions to be spatially juxtaposed, suggesting future research into soil biogeochemistry at these sites may be interesting. /// In summary, a new conceptual model of salt marsh ecohydrology is based on a definition of "ecohydrological zones" as the relevant unit of structure and function within the salt marsh ecohydrological system. Distinctive ecohydrological zones are created by hydraulic interactions between groundwater, vegetation, and the atmosphere. The specific nature of each zone depends both on the soil hydraulic properties resulting from the local geomorphological history and on the plant water uptake and transpiration governed by each plant species' unique physiology. The set of ecohydrological zones within a salt marsh are nested, in turn, within a coarser hydrologic system structure imposed by the tidal regime and larger intertidal groundwater flow system.