The Experts below are selected from a list of 82764 Experts worldwide ranked by ideXlab platform
Benjamin Pister - One of the best experts on this subject based on the ideXlab platform.
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urban marine ecology in southern california the ability of riprap structures to serve as rocky intertidal habitat
Marine Biology, 2009Co-Authors: Benjamin PisterAbstract:Increasing human populations along marine coastlines has lead to increasing urbanization of the marine environment. Despite decades of investigations on terrestrial ecosystems, the effect of urbanization on marine life is not well understood. Riprap is the rocky rubble used to build jetties, breakwaters, and armored Shorelines. Roughly 30% of the southern California shoreline supports some form of riprap, while 29% of the shoreline is natural rocky substrate. Astonishingly few studies have investigated this anthropogenic rocky habitat even though it rivals a natural habitat in area on a regional scale along a coastline that has been extensively studied. In this study, I compared the diversity and community structure of exposed rocky intertidal communities on four riprap and four natural sites in southern California. I ask the following questions: (1) does diversity or community composition differ between intertidal communities on riprap and natural rocky habitats in southern California, (2) if so, which organisms contribute to those differences, (3) which physical factors are contributing to these differences, and (4) do riprap habitats support higher abundances of invasive species than natural habitats? On average, riprap and natural rocky habitats in wave exposed environments in southern California did not differ from each other in diversity or community composition when considering the entire assemblage. However, when only mobile species were considered, they occurred in greater diversity on natural shores. These differences appear to be driven by wave exposure. The presence of invasive species was negligible in both natural and riprap habitats.
Charles H Peterson - One of the best experts on this subject based on the ideXlab platform.
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hurricane damage along natural and hardened estuarine Shorelines using homeowner experiences to promote nature based coastal protection
Marine Policy, 2017Co-Authors: Carter S Smith, Rachel K Gittman, Joel F Fodrie, Isabelle P Neylan, Steven B Scyphers, Joseph P Morton, Jonathan H Grabowski, Charles H PetersonAbstract:Abstract Growing coastal populations, rising sea levels, and likely increases in the frequency of major storm events will intensify coastal vulnerability in coming decades. Decisions regarding how and when to fortify estuarine Shorelines against coastal hazards, such as erosion, flooding, and attendant property damages, rest largely in the hands of waterfront-property owners. Traditionally, hard engineered structures (e.g. bulkheads, revetments, seawalls) have been used to protect coastal properties, based on the assumption that these structures are durable and effective at preventing erosion. This study evaluates the validity of these assumptions by merging results from 689 surveys of waterfront-property owners in NC with empirical shoreline damage data collected along estuarine Shorelines after Hurricanes Irene (2011) and Arthur (2014). The data show: 1) homeowners perceive bulkheads to be the most durable and effective at preventing erosion, but also the most costly; 2) compared to residents with revetments and natural Shorelines, property owners with bulkheads reported double the price to repair hurricane damage to their property and four times the cost for annual shoreline maintenance; 3) 93% of evident post-hurricane shoreline damage was attributable to bulkheads or bulkhead hybrids and a higher proportion of surveyed homeowners with bulkheads reported having property damage from hurricanes; and, 4) shoreline hardening increased by 3.5% from 2011 to 2016 along 39 km of the Outer Banks. These results suggest that bulkheads are not meeting waterfront property-owner expectations despite continued use, and that nature-based coastal protection schemes may be able to more effectively align with homeowner needs.
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living Shorelines can enhance the nursery role of threatened estuarine habitats
Ecological Applications, 2015Co-Authors: Rachel K Gittman, Charles H Peterson, Carolyn A Currin, Joel F Fodrie, Michael F Piehler, John Francis BrunoAbstract:Coastal ecosystems provide numerous services, such as nutrient cycling, climate change amelioration, and habitat provision for commercially valuable organisms. Ecosystem functions and processes are modified by human activities locally and globally, with degradation of coastal ecosystems by development and climate change occurring at unprecedented rates. The demand for coastal defense strategies against storms and sea-level rise has increased with human population growth and development along coastlines worldwide, even while that population growth has reduced natural buffering of Shorelines. Shoreline hardening, a common coastal defense strategy that includes the use of seawalls and bulkheads (vertical walls constructed of concrete, wood, vinyl, or steel), is resulting in a “coastal squeeze” on estuarine habitats. In contrast to hardening, living Shorelines, which range from vegetation plantings to a combination of hard structures and plantings, can be deployed to restore or enhance multiple ecosystem services normally delivered by naturally vegetated shores. Although hundreds of living shoreline projects have been implemented in the United States alone, few studies have evaluated their effectiveness in sustaining or enhancing ecosystem services relative to naturally vegetated Shorelines and hardened Shorelines. We quantified the effectiveness of (1) sills with landward marsh (a type of living shoreline that combines marsh plantings with an offshore low-profile breakwater), (2) natural salt marsh Shorelines (control marshes), and (3) unvegetated bulkheaded shores in providing habitat for fish and crustaceans (nekton). Sills supported higher abundances and species diversity of fishes than unvegetated habitat adjacent to bulkheads, and even control marshes. Sills also supported higher cover of filter-feeding bivalves (a food resource and refuge habitat for nekton) than bulkheads or control marshes. These ecosystem-service enhancements were detected on shores with sills three or more years after construction, but not before. Sills provide added structure and may provide better refuges from predation and greater opportunity to use available food resources for nekton than unvegetated bulkheaded shores or control marshes. Our study shows that unlike shoreline hardening, living Shorelines can enhance some ecosystem services provided by marshes, such as provision of nursery habitat.
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marshes with and without sills protect estuarine Shorelines from erosion better than bulkheads during a category 1 hurricane
Ocean & Coastal Management, 2014Co-Authors: Rachel K Gittman, Alyssa M Popowich, John F Bruno, Charles H PetersonAbstract:Acting on the perception that they perform better for longer, most property owners in the United States choose hard engineered structures, such as bulkheads or riprap revetments, to protect estuarine Shorelines from erosion. Less intrusive alternatives, specifically marsh plantings with and without sills, have the potential to better sustain marsh habitat and support its ecosystem services, yet their shoreline protection capabilities during storms have not been evaluated. In this study, the performances of alternative shoreline protection approaches during Hurricane Irene (Category 1 storm) were compared by 1) classifying resultant damage to Shorelines with different types of shoreline protection in three NC coastal regions after Irene; and 2) quantifying shoreline erosion at marshes with and without sills in one NC region by using repeated measurements of marsh surface elevation and marsh vegetation stem density before and after Irene. In the central Outer Banks, NC, where the strongest sustained winds blew across the longest fetch; Irene damaged 76% of bulkheads surveyed, while no damage to other shoreline protection options was detected. Across marsh sites within 25 km of its landfall, Hurricane Irene had no effect on marsh surface elevations behind sills or along marsh Shorelines without sills. Although Irene temporarily reduced marsh vegetation density at sites with and without sills, vegetation recovered to pre-hurricane levels within a year. Storm responses suggest that marshes with and without sills are more durable and may protect Shorelines from erosion better than the bulkheads in a Category 1 storm. This study is the first to provide data on the shoreline protection capabilities of marshes with and without sills relative to bulkheads during a substantial storm event, and to articulate a research framework to assist in the development of comprehensive policies for climate change adaptation and sustainable management of estuarine Shorelines and resources in U.S. and globally.
Jason D Toft - One of the best experts on this subject based on the ideXlab platform.
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multiscale impacts of armoring on salish sea Shorelines evidence for cumulative and threshold effects
Estuarine Coastal and Shelf Science, 2016Co-Authors: Megan N Dethier, Sarah M Heerhartz, Jason D Toft, Jeffery R Cordell, Wendel W Raymond, Aundrea Mcbride, A S Ogston, Helen BerryAbstract:Abstract Shoreline armoring is widespread in many parts of the protected inland waters of the Pacific Northwest, U.S.A, but impacts on physical and biological features of local nearshore ecosystems have only recently begun to be documented. Armoring marine Shorelines can alter natural processes at multiple spatial and temporal scales; some, such as starving the beach of sediments by blocking input from upland bluffs may take decades to become visible, while others such as placement loss of armoring construction are immediate. We quantified a range of geomorphic and biological parameters at paired, nearby armored and unarmored beaches throughout the inland waters of Washington State to test what conditions and parameters are associated with armoring. We gathered identical datasets at a total of 65 pairs of beaches: 6 in South Puget Sound, 23 in Central Puget Sound, and 36 pairs North of Puget Sound proper. At this broad scale, demonstrating differences attributable to armoring is challenging given the high natural variability in measured parameters among beaches and regions. However, we found that armoring was consistently associated with reductions in beach width, riparian vegetation, numbers of accumulated logs, and amounts and types of beach wrack and associated invertebrates. Armoring-related patterns at lower beach elevations (further vertically from armoring) were progressively harder to detect. For some parameters, such as accumulated logs, there was a distinct threshold in armoring elevation that was associated with increased impacts. This large dataset for the first time allowed us to identify cumulative impacts that appear when increasing proportions of Shorelines are armored. At large spatial and temporal scales, armoring much of a sediment drift cell may result in reduction of the finer grain-size fractions on beaches, including those used by spawning forage fish. Overall we have shown that local impacts of shoreline armoring can scale-up to have cumulative and threshold effects -- these should be considered when managing impacts to public resources along the coast.
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effects of shoreline engineering on shallow subtidal fish and crab communities in an urban estuary a comparison of armored Shorelines and nourished beaches
Ecological Engineering, 2015Co-Authors: Stuart H Munsch, Jeffery R Cordell, Jason D ToftAbstract:Abstract Shoreline armoring is common worldwide, yet its ecological effects have only recently been investigated. In this study, we surveyed shallow subtidal fish and crab communities at three sites with Shorelines modified by seawall and riprap armoring and at three beaches with no armoring, all along the urbanized Elliott Bay shoreline of Seattle, WA (USA). Similar to many urban areas there is little natural shoreline remaining in Elliott Bay and beach sites were nourished with sediment that was similar to the historical structure of ambient nearshore habitats. We visually surveyed fish and crabs along scuba dive transects at these sites for eighteen months to quantify the composition of their communities and the association of fish and crabs with substrate types. The community composition and substrate type associations were similar among seawall sites and distinct from those at nourished beaches. Some species were predominantly associated with one substrate type (e.g., sand, riprap) and their densities at each site corresponded to the availability of this substrate type. Our results suggest that hard structures in engineered subtidal habitats may benefit some species that select for these introduced structures despite these structures not occurring historically. It is also clear that the creation of nourished beaches within armored Shorelines can maintain different fish and crab communities than those associated with armoring, even in highly urbanized systems. Our study contributes to a growing literature that suggests that shoreline armoring and other types of habitat modifications affect the ecology of nearshore waters and the composition of nearshore communities.
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movement patterns and feeding behavior of juvenile salmon oncorhynchus spp along armored and unarmored estuarine Shorelines
Environmental Biology of Fishes, 2015Co-Authors: Sarah M Heerhartz, Jason D ToftAbstract:Estuarine nearshore environments are important habitats for many organisms, including juveniles of several Pacific salmon species (Oncorhynchus spp.). These habitats provide shallow water and high prey productivity, but are increasingly modified by anthropogenic activity including shoreline armoring, which disrupts connectivity between aquatic and terrestrial realms and artificially steepens the shore. Such effects may have adverse consequences for juvenile salmon, particularly Chinook (O. tshawytscha) and chum (O. nerka), which are known to rely on shallow, productive nearshore habitats for foraging and refuge from predators during their outmigration from natal streams to the sea. We developed snorkel methods to quantify feeding rates, movement rates, and path complexity of juvenile salmon along armored and unarmored Shorelines in Puget Sound, WA, USA. We found that juvenile salmon had relatively high feeding rates along all shoreline types, but that path straightness and movement rates showed some variation between armored and unarmored sites. Feeding fish swam in more complex paths and were observed in larger schools than non-feeding fish, and path straightness and movement rate were negatively correlated with proportion of time feeding. Feeding behavior, school size, and movement rates also showed variation by species. Shoreline type (armored or unarmored) influenced juvenile salmon distribution, and unarmored Shorelines appear to accommodate a greater diversity of movement patterns than armored Shorelines. Our results show that juvenile salmon feed at high rates along armored and unarmored estuarine Shorelines, thus decreased prey availability or altered prey resources are likely the most detrimental foraging effects of armoring in estuarine nearshore ecosystems.
Elizabeth H. Boak - One of the best experts on this subject based on the ideXlab platform.
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Shoreline Definition and Detection: A Review
Journal of Coastal Research, 2005Co-Authors: Elizabeth H. Boak, Ian L. TurnerAbstract:BOAK, E.H. and TURNER, I.L., 2005. Shoreline Definition and Detection: A Review. Journal of Coastal Research, 21(4), 688‐703. West Palm Beach (Florida), ISSN 0749-0208. Analysis of shoreline variability and shoreline erosion-accretion trends is fundamental to a broad range of investigations undertaken by coastal scientists, coastal engineers, and coastal managers. Though strictly defined as the intersection of water and land surfaces, for practical purposes, the dynamic nature of this boundary and its dependence on the temporal and spatial scale at which it is being considered results in the use of a range of shoreline indicators. These proxies are generally one of two types: either a feature that is visibly discernible in coastal imagery (e.g., highwater line [HWL]) or the intersection of a tidal datum with the coastal profile (e.g., mean high water [MHW]). Recently, a third category of shoreline indicator has begun to be reported in the literature, based on the application of imageprocessing techniques to extract proxy shoreline features from digital coastal images that are not necessarily visible to the human eye. Potential data sources for shoreline investigation include historical photographs, coastal maps and charts, aerial photography, beach surveys, in situ geographic positioning system Shorelines, and a range of digital elevation or image data derived from remote sensing platforms. The identification of a ‘‘shoreline’’ involves two stages: the first requires the selection and definition of a shoreline indicator feature, and the second is the detection of the chosen shoreline feature within the available data source. To date, the most common shoreline detection technique has been subjective visual interpretation. Recent photogrammetry, topographic data collection, and digital image-processing techniques now make it possible for the coastal investigator to use objective shoreline detection methods. The remaining challenge is to improve the quantitative and process-based understanding of these shoreline indicator features and their spatial relationship relative to the physical land‐water boundary.
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A laboratory study of the 'shoreline' detected in video imagery
17th Australasian Coastal and Ocean Engineering Conference 2005 and the 10th Australasian Port and Harbour Conference 2005 COASTS and PORTS 2005, 2005Co-Authors: Elizabeth H. Boak, I.l. Turner, R.n. MertonAbstract:The identification of the 'shoreline' is of fundamental importance to coastal research and management. Modern video image capture and processing technology allows for continuous, high-frequency sampling of the coastal zone, and in recent years, several techniques have been developed to extract 'Shorelines' from these images. The image processing techniques separate the land/water interface by identifying contrasting 'wet' and 'dry' pixel characteristics within time-averaged images. A fundamental challenge is to understand the physical swash features (sediments, water depth, turbulence, aeration and suspended sediment concentration) and viewing geometry (senor zenith, solar zenith and sensor-solar azimuth) mat determine the 'shoreline' within these digital images. An extensive laboratory experiment has been undertaken to simulate beachface, swash and groundwater processes that occur co-incident to the 'shoreline'. Data from a hyperspectral sensor, measuring reflectance at 512 bands between 325 nm and 1075 nm has been integrated over the respective red, blue and green bands of the video sensor to replicate the visible wavelengths captured at the coast in digital images. The most prominent physical feature affecting the reflectance of the dry beach and shallow water depths are the sediment characteristics of the site, in particular sediment colour. Significant relationships also exist between red and very near infrared (VNIR) wavelengths (∼650 nm -750 nm) and water depth due to absorption of light in these wavelengths by pure water, and between visible and VNIR wavelengths and the presence or absence of foaminess. Winter versus summer solar elevation and the sensor zenith also affect the detection of the 'shoreline'.
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Shoreline Definition and Detection: A Review
Journal of Coastal Research, 2005Co-Authors: Elizabeth H. Boak, Ian L. TurnerAbstract:Analysis of shoreline variability and shoreline erosion-accretion trends is fundamental to a broad range of investi-gations undertaken by coastal scientists, coastal engineers, and coastal managers. Though strictly defined as the intersection of water and land surfaces, for practical purposes, the dynamic nature of this boundary and its dependence on the temporal and spatial scale at which it is being considered results in the use of a range of shoreline indicators. These proxies are generally one of two types: either a feature that is visibly discernible in coastal imagery (e.g., high-water line [HWL]) or the intersection of a tidal datum with the coastal profile (e.g., mean high water [MHW]). Recently, a third category of shoreline indicator has begun to be reported in the literature, based on the application of image-processing techniques to extract proxy shoreline features from digital coastal images that are not necessarily visible to the human eye. Potential data sources for shoreline investigation include historical photographs, coastal maps and charts, aerial photography, beach surveys, in situ geographic positioning system Shorelines, and a range of digital elevation or image data derived from remote sensing platforms. The identification of a ''shoreline'' involves two stages: the first requires the selection and definition of a shoreline indicator feature, and the second is the detection of the chosen shoreline feature within the available data source. To date, the most common shoreline detection technique has been subjective visual interpretation. Recent photogrammetry, topographic data collection, and digital image-processing techniques now make it possible for the coastal investigator to use objective shoreline detection methods. The remaining challenge is to improve the quantitative and process-based understanding of these shoreline indicator features and their spatial relationship relative to the physical land–water boundary.
Rachel K Gittman - One of the best experts on this subject based on the ideXlab platform.
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hurricane damage along natural and hardened estuarine Shorelines using homeowner experiences to promote nature based coastal protection
Marine Policy, 2017Co-Authors: Carter S Smith, Rachel K Gittman, Joel F Fodrie, Isabelle P Neylan, Steven B Scyphers, Joseph P Morton, Jonathan H Grabowski, Charles H PetersonAbstract:Abstract Growing coastal populations, rising sea levels, and likely increases in the frequency of major storm events will intensify coastal vulnerability in coming decades. Decisions regarding how and when to fortify estuarine Shorelines against coastal hazards, such as erosion, flooding, and attendant property damages, rest largely in the hands of waterfront-property owners. Traditionally, hard engineered structures (e.g. bulkheads, revetments, seawalls) have been used to protect coastal properties, based on the assumption that these structures are durable and effective at preventing erosion. This study evaluates the validity of these assumptions by merging results from 689 surveys of waterfront-property owners in NC with empirical shoreline damage data collected along estuarine Shorelines after Hurricanes Irene (2011) and Arthur (2014). The data show: 1) homeowners perceive bulkheads to be the most durable and effective at preventing erosion, but also the most costly; 2) compared to residents with revetments and natural Shorelines, property owners with bulkheads reported double the price to repair hurricane damage to their property and four times the cost for annual shoreline maintenance; 3) 93% of evident post-hurricane shoreline damage was attributable to bulkheads or bulkhead hybrids and a higher proportion of surveyed homeowners with bulkheads reported having property damage from hurricanes; and, 4) shoreline hardening increased by 3.5% from 2011 to 2016 along 39 km of the Outer Banks. These results suggest that bulkheads are not meeting waterfront property-owner expectations despite continued use, and that nature-based coastal protection schemes may be able to more effectively align with homeowner needs.
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living Shorelines can enhance the nursery role of threatened estuarine habitats
Ecological Applications, 2015Co-Authors: Rachel K Gittman, Charles H Peterson, Carolyn A Currin, Joel F Fodrie, Michael F Piehler, John Francis BrunoAbstract:Coastal ecosystems provide numerous services, such as nutrient cycling, climate change amelioration, and habitat provision for commercially valuable organisms. Ecosystem functions and processes are modified by human activities locally and globally, with degradation of coastal ecosystems by development and climate change occurring at unprecedented rates. The demand for coastal defense strategies against storms and sea-level rise has increased with human population growth and development along coastlines worldwide, even while that population growth has reduced natural buffering of Shorelines. Shoreline hardening, a common coastal defense strategy that includes the use of seawalls and bulkheads (vertical walls constructed of concrete, wood, vinyl, or steel), is resulting in a “coastal squeeze” on estuarine habitats. In contrast to hardening, living Shorelines, which range from vegetation plantings to a combination of hard structures and plantings, can be deployed to restore or enhance multiple ecosystem services normally delivered by naturally vegetated shores. Although hundreds of living shoreline projects have been implemented in the United States alone, few studies have evaluated their effectiveness in sustaining or enhancing ecosystem services relative to naturally vegetated Shorelines and hardened Shorelines. We quantified the effectiveness of (1) sills with landward marsh (a type of living shoreline that combines marsh plantings with an offshore low-profile breakwater), (2) natural salt marsh Shorelines (control marshes), and (3) unvegetated bulkheaded shores in providing habitat for fish and crustaceans (nekton). Sills supported higher abundances and species diversity of fishes than unvegetated habitat adjacent to bulkheads, and even control marshes. Sills also supported higher cover of filter-feeding bivalves (a food resource and refuge habitat for nekton) than bulkheads or control marshes. These ecosystem-service enhancements were detected on shores with sills three or more years after construction, but not before. Sills provide added structure and may provide better refuges from predation and greater opportunity to use available food resources for nekton than unvegetated bulkheaded shores or control marshes. Our study shows that unlike shoreline hardening, living Shorelines can enhance some ecosystem services provided by marshes, such as provision of nursery habitat.
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marshes with and without sills protect estuarine Shorelines from erosion better than bulkheads during a category 1 hurricane
Ocean & Coastal Management, 2014Co-Authors: Rachel K Gittman, Alyssa M Popowich, John F Bruno, Charles H PetersonAbstract:Acting on the perception that they perform better for longer, most property owners in the United States choose hard engineered structures, such as bulkheads or riprap revetments, to protect estuarine Shorelines from erosion. Less intrusive alternatives, specifically marsh plantings with and without sills, have the potential to better sustain marsh habitat and support its ecosystem services, yet their shoreline protection capabilities during storms have not been evaluated. In this study, the performances of alternative shoreline protection approaches during Hurricane Irene (Category 1 storm) were compared by 1) classifying resultant damage to Shorelines with different types of shoreline protection in three NC coastal regions after Irene; and 2) quantifying shoreline erosion at marshes with and without sills in one NC region by using repeated measurements of marsh surface elevation and marsh vegetation stem density before and after Irene. In the central Outer Banks, NC, where the strongest sustained winds blew across the longest fetch; Irene damaged 76% of bulkheads surveyed, while no damage to other shoreline protection options was detected. Across marsh sites within 25 km of its landfall, Hurricane Irene had no effect on marsh surface elevations behind sills or along marsh Shorelines without sills. Although Irene temporarily reduced marsh vegetation density at sites with and without sills, vegetation recovered to pre-hurricane levels within a year. Storm responses suggest that marshes with and without sills are more durable and may protect Shorelines from erosion better than the bulkheads in a Category 1 storm. This study is the first to provide data on the shoreline protection capabilities of marshes with and without sills relative to bulkheads during a substantial storm event, and to articulate a research framework to assist in the development of comprehensive policies for climate change adaptation and sustainable management of estuarine Shorelines and resources in U.S. and globally.
