Deborah J Shafer

Dredging often occurs near sensitive habitat. Risk characterization is an integral part of dredging regulatory approval and sound dredging practice. This paper describes a risk characterization framework for evaluating risk associated with sediment released during dredging operations. Sediment release risk assessment is required to balance dredging...

This study describes nearshore Chesapeake Bay sedimentation at sites adjacent to and landward of 24 segmented breakwaters, varying in age (1-19 years) and physical setting. Grain-size and organic-content profiles are examined at the breakwater-protected sites to assess potential changes induced by breakwater installation as well as at the adjacent-...

Model studies were conducted to investigate the potential coral reef sediment exposure from dredging associated with proposed development of a deepwater wharf in Apra Harbor, Guam. The Particle Tracking Model (PTM) was applied to quantify the exposure of coral reefs to material suspended by the dredging operations at two alternative sites. Key PTM...

We developed a spatially-explicit, habitat suitability model that can be used to identify and predict areas at higher risk for non-native dwarf eelgrass (Zostera japonica) invasion. The niche-based model uses simple readily available environmental parameters (depth, near shore slope, and salinity) to quantitatively describe habitat suitable for Z....

Coral reefs are in decline worldwide due to anthropogenic stressors including reductions in water and substratum quality. Dredging results in the mobilization of sediments, which can stress and kill corals via increasing turbidity, tissue damage and burial. The Particle Tracking Model (PTM) was applied to predict the potential impacts of dredging-a...

Seagrasses can colonize unstructured mudflats either through clonal growth or seed germination and survival. Zostera japonica is an introduced seagrass in North America that has rapidly colonized mudflats along the Pacific Coast, leading to active management of the species. Growth and physiology have been evaluated; however, there is little informa...

At least two seagrass congeners in the genus Zostera are found along the Pacific Coast of North America: native Zostera marina L. and the non-native Zostera japonica Aschers. & Graebn. Efforts to understand the drivers behind the expanding colonization of Z. japonica have led to interest in the biology and ecology of this species. In most locations...

Healthy seagrass is considered a prime indicator of estuarine ecosystem function. On the Pacific coast of North America, at least two congeners of Zostera occur: native Zostera marina, and introduced, Zostera japonica. Z. japonica is considered “invasive” and therefore, ecologically and economically harmful by some, while others consider it benign...

Zostera japonica is a non-indigenous seagrass that is expanding along the Pacific Coast of North America. The ecophysiology of this seagrass is poorly studied and management of the species is fragmented. This split-plot mesocosm experiment was designed to evaluate the response of Z. japonica to chronic, extreme temperature and salinity stress to fa...

On the Pacific coast of North America two seagrass species in the genus Zostera co-exist; the native species Zostera marina, and an introduced species, Zostera japonica. These two species typically occupy separate tidal elevations, with Z. marina occupying the lower intertidal and shallow subtidal zones, and Z. japonica occupying the mid- to upper...

Marine and intertidal (coastal) plant habitats, such as mangroves, saltmarshes, seagrass beds and attached seaweed communities provide a huge range of ecosystem services, including protection of shorelines from storm surges and waves, prevention of coastal erosion, sequestering of carbon, climate regulation, sustaining fisheries production, support...

Model studies have been conducted to investigate the potential coral reef exposure from proposed dredging associated with development of a new deepwater wharf in outer Apra Harbor, Guam. The Particle Tracking Model (PTM) was applied to quantify the exposure of coral reefs to material suspended by the dredging operations at proposed sites. Key PTM f...

Photosynthetic responses were quantified for two Zostera japonica Aschers. and Graebn. populations from the northern and southern limits of distribution exposed to a range of salinities along the Pacific Coast of North America. Plants were collected from Padilla Bay, Washington (northern) and Coos Bay, Oregon, USA (southern) and cultured together i...

PROBLEM: Seeds offer an efficient and cost-effective method for providing new plants for large-scale plantings and hence are used for the production of all major domesticated crop plants. Similarly, seed propagation offers the most cost-effective approach for restoring large, genetically diverse, self-maintaining populations of submersed aquatic pl...

Many procedures have been developed to assess seed bank characteristics, and most can be grouped into either of 2 categories: seedling emergence assays or seed separation from substrate. These procedures are particularly useful in predicting vegetation recurrence and determining need for restoration or control strategies through estimates of seed b...

Restoration of submerged aquatic vegetation from seed has been hampered by a lack of information on the appropriate conditions for collecting, processing, and storing seeds prior to dispersal. Seeds must be processed and stored under conditions that maintain seed viability, meet dormancy requirements, and prevent premature germination. This study e...

We tested the hypothesis that currents, waves, and sediment grain size affect the dispersal of seeds and seedlings of the submersed angiosperms Ruppia maritima, Potamogeton perfoliatus and Stuckenia pectinata. Seed settling velocities and initiation of motion of seeds and seedlings and distance transported were quantified on four sediment types und...

Protocols are now available for seed harvest, storage and germination of several mesohaline and polyhaline species; however, low seedling survival rates point to the need for an increased understanding of factors affecting seedling establishment. Depth of seed burial in sediments and initial seedling growth rates are shown to be limiting factors fo...

BACKGROUND: Oysters are filter-feeding bivalve molluscs that form cohesive reefs in estua-rine and near-coastal waters. In addition to their economic value, oysters can exert a powerful influence on water quality, phytoplankton productivity, and nutrient cycling (Dame 1996; Ulanowicz and Tuttle 1992); they also affect current patterns, flow, and se...

During the last several decades, seagrasses and related submerged aquatic vegetation (SAV) have been lost from shallow waters of Chesapeake Bay (Orth and Moore 1983) and other coastal ecosystems worldwide (Short and Wyllie-Echeverria 1996). Losses of SAV beds are of particular concern because these plants tend to create rich habitat and food for an...

To reduce the loss of seagrasses due to dock construction and shading, dock construction guidelines for areas containing seagrass beds were developed in 2001. This study indentifies 68 docks located in five regions throughout Florida and Puerto Rico that have been constructed since 2001. The docks are evaluated for compliance with the Seagrass Guid...

The current distribution of the introduced seagrass Zostera japonica is restricted to the mid- to upper intertidal zone in the coastal Pacific Northwest region of North America. The climate in this region is cool and wet, becoming hotter and dryer with increasing distance southward. Since temperature is likely to be an important factor affecting di...

This technical note summarizes the results of an experiment designed to investigate the short-term effects of sediment burial on the surfgrass Phyllospadix scouleri. P. scouleri inhabits rocky shorelines from Southeast Alaska to Baja California along the Northeast Pacific coast of North America.

The Chesapeake Bay is one of the world's largest estuar-ies. Dramatic declines in the abundance and distribution of submerged aquatic vegetation (SAV) in the Chesapeake Bay over the last few decades led to a series of management decisions aimed at protecting and restoring SAV popula-tions throughout the bay. In 2003, the Chesapeake Bay Pro-gram est...

Dramatic declines in American wild celery (Vallisneria americana Michaux), a native submersed aquatic plant, have been widely reported in the United States since the 1960s, especially from the Midwest to the Northeast. Though methods for restoration are being developed and implemented, progress has been hampered by the need for greater understandin...

In 2003, the U.S. Army Engineer Research and Development Center (ERDC) and the National Oceanic and Atmospheric Administration Chesapeake Bay Office began a comprehensive research effort to restore submerged aquatic vegetation (SAV) in the Chesapeake Bay region. The effort employed an agricultural approach to restore under-water grasses by using se...

Maintenance dredging in the Black Channel portion of the Portsmouth Harbor and Piscatiqua River Federal Navigation Project in Portsmouth (commonly referred to as Sagamore Creek) occurs in close proximity to submersed aquatic vegetation (SAV). Species, density, and spatial distribution are of concern to resource agencies given the potential impacts...

Monitoring periods for compensatory wetland mitigation projects are relatively short, typically 3 to 5years. Although forested wetlands may require decades to develop structural characteristics similar to those of natural systems, studies that describe long-term trends in site development are rare. Eighteen mitigation sites in Florida that had orig...

This technical note summarizes the current status of our knowledge regarding restoration of surfgrasses (Phyllospadix spp.) in the northeastern Pacific, and identifies research needs to improve the success of future restoration efforts. Surfgrass Restoration in the Northeast Pacific. Available from: https://www.researchgate.net/publication/242076...

This technical note documents long-term trends in stand development for mangrove mitigation sites in southern and central Florida, and compares structural characteristics of planted and natural mangrove sites.

Photosynthetic processes in Zostera japonica, an upper intertidal species, were found to be more severely affected by desiccation than Z. marina, a lower intertidal and subtidal species, at comparable levels of tissue water content. The data indicate that photosynthetic responses to desiccation at the level of the individual leaf are insufficient t...

Seagrasses are rooted flowering marine plants that provide a variety of ecosystem services to the coastal areas they colonize. Attenuation of currents and waves and sediment stabilization are often listed among these services. Although we have a reasonably good understanding of how currents affect seagrasses and vice-versa, less is known about inte...

Monitoring the success of large-scale submerged aquatic vegetation (SAV) restoration projects requires the ability to detect and map the presence or absence of SAV, as well as assess changes in SAV distributions over time. Aerial photography is generally considered to be the most widely used, versatile, and relatively economical form of remote sens...

A previous pilot study (Ailstock and Shafer 2004) established the seed reproductive potential of two species of submerged aquatic angiosperms, Ruppia maritima (widgeon grass) and Potamogeton perfoliatus (redhead grass), that predominate in the mesohaline reaches of the mid-Chesapeake Bay. This paper outlines a system for the collection, processing,...

While speculation on effects of dredging on seagrass beds is plentiful, actual empirical data documenting these effects are not. In this study, acoustic-based seagrass mapping techniques were used to generate detailed maps of seagrass distribution before and after dredging operations. Eelgrass (Zostera marina) within Scituate Harbor, MA, was monito...

https://hdl.handle.net/11681/3566

This technical note outlines protocols for assessing the reproductive potential of Ruppia maritima and Potamogeton perfoliatus, two species of submerged aquatic plants that pre-dominate in the mesohaline reaches of the mid-Chesapeake Bay. Once reproductive potential by seed is defined for healthy populations of these species, their life cycles can...

This technical note provides contract specifications that can be used as a template by USACE personnel for contracting the installation of willow (Salix spp.) stakes for streambank stabilization (Figure 1). This example provides biologists, engineers, project managers, and others with information that can be used to develop contract specifications....

Twenty-three Section 404 permits in central Pennsylvania (covering a wetland age range of 1-14 years) were examined to determine the type of mitigation wetland permitted, how the sites were built, and what success criteria were used for evaluation. Most permits allowed for mitigation out-of-kind, either vegetatively or through hydrogeomorphic class...

This technical note provides an example of contract specifications that can be used as a template by USACE biologists, engineers, or contracting officers for contracting the planting of bottomland hardwood (BLH) seedlings. However, it is not intended to substitute for a basic understanding of appropriate planting techniques and other wetland restor...

The Hydrogeomorphic (HGM) Approach is a collection of concepts and methods for developing functional indices and subsequently using them to assess the capacity of a wetland to perform functions relative to similar wetlands in a region The approach was initially designed to be used in the context of the Clean Water Act Section 404 Regulatory Program...

Fourteen dredged material marshes andfourteen natural marshes along the Texas, USA, coastare compared on the basis of 1) edge: area ratios, 2)relative exposure index values, 3) elevation profiles,4) elevation of Spartina alterniflora, 5) soilorganic carbon content, 6) soil silt-clay content, and7) belowground plant biomass. Although edge: areacompa...

Aboveground and belowground biomass, density, blade length, and chlorophyll content of seagrass growing directly under docks were compared with adjacent unshaded sites. The amount of light reduction due to dock shading was measured using quantum spherical irradiance meters. Seagrasses were present under docks; they were shaded such that light level...

This technical note provides recommendations for the design and construction of dock and terminal platform structures to minimize impacts to seagrasses, and describes the construction of two experimental platforms in St. Andrew Bay, FL.

this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. The findings of this report are not to be construed as an official Department of the Army position, unless so designated by other authorized doc...

Seagrass beds represent some of the most valuable aquatic habitats within the marine ecosystem. They provide critical refuge and foraging grounds for a diversity of organisms, including crustaceans and other invertebrates, as well as fish. Many of these species are economically important. Corps of Engineers districts frequently need to assess the c...

A survey to assess community characteristics, density, population demography of dominant species, and the likelihood of finding endangered species of freshwater mussels (Unionidae) was conducted in the lower Ohio River near Olmsted, IL. Data will be used to analyze impacts of construction and operation of a new lock and dam at River Mile (RM) 964.4...

PURPOSE: This technical note presents an evaluation of the wave climate at eight natural and created coastal wetland sites in an effort to identify the existence of critical wave energy thresholds for long-term marsh stability. This information could be used to help determine the minimum degree of protective structures necessary for successful esta...

DEFINITION: Micropropagation is a technique that manipulates small quantities of axenic plant mate- rial, ranging from single cells to stem segments, under conditions favorable to the formation of new plants. It has proven to be the most efficient and cost-effective method of propagating large numbers of clonal offspring for many agronomic crops, i...

BACKGROUND: Submerged aquatic vegetation (SAV) performs many important ecosystem functions, including wave attenuation and sediment stabilization, water quality improvement, primary production, food web support for secondary consumers, and provision of critical nursery and refuge habitat for fisheries species (Orth et al. 2006a). Over the last few...