Download or read book Long term Spatial temporal Eelgrass Zostera Marina Habitat Change 1932 2016 in the Salish Sea Using Historic Aerial Photography and Unmanned Aerial Vehicle written by Natasha K. Nahirnick and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Eelgrass (Zostera marina) is a critical nearshore marine habitat for juvenile Pacific salmon (Oncorhynchus spp.) as they depart from their natal streams. Given the poor marine survival of Coho (O. kisutch) and Chinook (O. tshawytscha) salmon juveniles in recent decades, it is hypothesized that deteriorating eelgrass habitats could contribute to their low survival. The primary goal of this research was to investigate the possible long-term spatial-temporal trends in eelgrass habitat in the Salish Sea and was addressed by two main objectives: (1) Define a methodology for mapping eelgrass habitats using UAV imagery to create a baseline for long-term mapping; and (2) Assess changes in eelgrass area coverage and fragmentation over the period of 1932-2016 using historic aerial photographs and Unmanned Aerial Vehicle (UAV) imagery, and assess the relationship between eelgrass and residential housing density and shoreline activities. Three study sites in the Southern Gulf Islands of the Salish Sea were chosen for analysis. The overall accuracies of eelgrass delineation from UAV imagery were 95.3%, 88.9%, and 90.1% for Village Bay, Horton Bay, and Lyall Harbour, respectively. The UAV method was found to be highly effective for this size of study site, however results were impacted by the environmental conditions at the time of acquisition, namely: sun angle, tidal height, cloud cover, water clarity, and wind speed. The results from the first objective were incorporated into a long-term dataset of historic aerial photography and used to evaluate changes in eelgrass area and fragmentation. All three eelgrass meadows showed a deteriorating trend in eelgrass condition. On average, eelgrass area coverage decreases by 41% while meadow complexity as indicated by the shape index increases by 76%. Shoreline activities (boats, docks, log booms, and shoreline armouring) and residential housing density increased markedly at all sites over the study period. By using a linear correlation model, it was revealed that eelgrass areal coverage and fragmentation (Shape Index) were, in general, very strongly correlated to these landscape-level coastal environmental indicators. While this correlation model is not meant to show a direct causative impact on eelgrass at these sites, these results suggest an overall deterioration of coastal environmental health in the Salish Sea due to a dramatic increase in the use of the coastal zone, as well as likely declines in water quality due to urbanization.

Download or read book Status of Eelgrass Zostera Marina on the North Atlantic Coast February 1938 written by Clarence Cottam and published by . This book was released on 1938 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Long term Changes in Eelgrass Zostera Marina Distribution in Taunton Bay ME written by Tara Goodrich (Mae) and published by . This book was released on 2006 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Spatial Model of Eelgrass Zostera Marina Habitat in Humboldt Bay California written by Whelan Gilkerson and published by . This book was released on 2008 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was conducted to model the extent of eelgrass habitat in Humboldt Bay, California through physical surveys of the maximum depths and upper limits of growth in conjunction with recently acquired high-resolution bathymetry data and supplemental imagery. A combination of chronic turbidity, frequent coastal stratus, and wind-waves, make Humboldt Bay a challenging environment to assess subtidal eelgrass (Zostera marina) habitat from remotely-sensed imagery. Additionally, eelgrass and green algae overlap extensively in shallow intertidal areas, confounding efforts to distinguish between habitat types from imagery alone. A relative exposure index (REI) was developed to identify areas of eelgrass habitat that may be prone to disturbance from wind-waves. Approximately 2200 hectares of eelgrass habitat were identified. Accuracy was assessed at 91% for modeled eelgrass habitat in South Humboldt Bay based on a comparison with hyperspectral imagery captured in October, 2004. Modeling the extent of eelgrass habitat represents an important step towards understanding the extent to which future restoration or mitigation may be possible in Humboldt Bay.

Download or read book Assessing Spatial and Temporal Changes in Seagrass Communities Using Historical Aerial Photography and Satellite Data written by Mariana C. León Pérez and published by . This book was released on 2016 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Distribution Production and Historical Changes in Abundance of Eelgrass Zostera Marina L in Southeastern Massachusetts written by Joseph Edward Costa and published by . This book was released on 1988 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Status of Eelgrass Zostera Marina on the North Atlantic Coast January 1937 1 Classic Reprint written by John J. Lynch and published by Forgotten Books. This book was released on 2018-09-09 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Status of Eelgrass (Zostera Marina) On the North Atlantic Coast, January 1937/1 Present Situation Regarding Eelgrass (zostera marina) Information on the history and extent of disappearance, effects of the disappearance, and past periods of scarcity is contained in the former paper. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Download or read book A Study of the Spatial and Temporal Variation of Eelgrass Zostera Marina Its Epiphytes and the Grazer Phyllaplysia Taylori in Arcata Bay California USA written by Aimee Louise Keiser and published by . This book was released on 2004 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transplanted Eelgrass Zostera Marina L in the Great Bay Estuary written by Nancy Tay Evans and published by . This book was released on 2002 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Eelgrass Zostera Marina Ecosystems in Eastern Canada and Their Importance to Migratory Waterfowl written by Mélanie-Louise Leblanc and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Seagrasses are marine flowering plants that create some of the most productive coastal habitats globally and play a key role in the functioning of nearshore ecosystems. The most common seagrass genus in Canada is Zostera and the species Zostera marina (eelgrass) is the predominant seagrass in intertidal and subtidal shoreline zones along the Atlantic, Pacific, and eastern James Bay coasts. Eelgrass has specific habitat requirements, with growth and productivity optimized within particular ranges of salinity, temperature, light availability, and nutrient concentrations. Large eelgrass meadows can impact nearshore environments by filtering the water column, stabilizing sediment, buffering shorelines, and providing habitat for various marine and coastal species, including commercially important species like Atlantic cod (Gadus morhua) and lobster (Homarus americanus). Eelgrass is also a vital food resource for migratory waterfowl, notably Canada Geese (Branta canadensis), Pacific Black Brant (Branta bernicla nigricans), and Atlantic Brant (Branta bernicla hrota). Despite their ecological importance, seagrasses are among the most vulnerable coastal ecosystems on the planet. The global loss of seagrass has been linked to a variety of human activities, including pollution, invasive species, and catchment modifications. There is an urgent need to improve monitoring of seagrass responses to environmental change, better document the importance of seagrass meadows to species reliant on them for food and habitat, and advance effective management and conservation of seagrass ecosystems. In this thesis, I investigated the spatiotemporal dynamics of eelgrass meadows in eastern Canada and the importance of eelgrass as a food source for migratory waterfowl, using remote sensing data, long-term monitoring data (biomass, density, and cover), and field observations. In Chapter 3, I used a novel cost-efficient approach for satellite imaging time-series to examine changes in eelgrass distribution and abundance from 1984 to 2017 in a wetland of international importance in northeastern New Brunswick. With minimal ground truth data, the novel time-series approach revealed a slow and steady decline in eelgrass abundance in some areas of the estuary. In contrast, other areas were characterized by highly dynamic shifts in eelgrass cover over time. I demonstrated how time-series analysis can be used to identify potential drivers of seagrass change and the benefits of including time-series analysis in seagrass monitoring programs. In Chapter 4, I contributed to advancing knowledge of migratory waterfowl stopover behaviour by examining the influence of eelgrass and human activities on Canada Geese habitat selection. Combining field observations of Canada Geese and the eelgrass distribution maps produced in Chapter 3, I found that Canada Geese selected areas with high eelgrass availability during periods of low human disturbance, which emphasized the importance of eelgrass as a food source during the fall migration. However, higher levels of human disturbance led to a redistribution of geese away from dense eelgrass meadows. In Chapter 5, I presented new insights into the recent and current state of eelgrass along the eastern coast of James Bay after a drastic and large-scale decline in the late 1990s. By aggregating, synthesizing, and analyzing long-term monitoring data and current surveys, spanning 1982 - 2020, I provided the first quantitative evidence that changes in eelgrass biomass in northeastern James Bay may reflect synergistic impacts of climate change and altered freshwater discharge regimes. Overall, this thesis advances understanding of how temperate and subarctic Zostera marina ecosystems and associated fauna respond to coastal development and climate change"--

Download or read book Investigating Perennial Annual Eelgrass Zostera Marina L in Padilla Bay as Potential Donor Sources for Seed based Restoration written by Yuki Wilmerding and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper explores recovery of eelgrass (Zostera marina L.) meadows through seed-based restoration to address declines from natural and anthropogenic disturbances. The study focuses on the Joe Leary meadow site in Padilla Bay, Washington, aiming to (1) determine the spatial distribution of perennial and annual Z. marina, (2) understand variation in flowering shoot density and potential seed production, and (3) compare the phenology of flowering shoots. These objectives were investigated using field-based methods to collect presence/absence transect data for delineation, quadrat-based count data, and monitor seed development. Data collection occurred in the summer throughout the flowering life stage of eelgrass in the site. The study found spatial and temporal variation in the distribution, density, and phenology of flowering perennial and annual populations. Delineation methods revealed that annuals have a similar range in the intertidal as perennials, with differences highlighted in response to potential stress indicators such as proximity to the slough, algal mats, or elevation. Quadrat-based monitoring found annual shoots in the transect higher in the intertidal, above the perennial population. Phenology data indicated that perennial shoots flower about a month prior to annual shoots. While the study advises against using perennial flowering shoots for restoration due to low densities, it emphasizes Joe Leary's potential as a donor site for flowering annuals for seed-based restoration. Careful considerations are crucial to avoid unintended introductions of non-native species. The research concludes with recommendations for refining delineation methods, enhancing understanding of eelgrass population dynamics, and optimizing seed collection strategies for genetically diverse and resilient restoration in the face of climate change.

Download or read book Under what Conditions Could Eelgrass Measurably Drawdown Carbon written by Tyler J. Tran and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seagrass meadows, common to coastal habitats, have been identified as potential short-term refugia for calcifying organisms from ocean acidification (OA). In nearshore, soft-sediment habitats of the Salish Sea, eelgrass (Zostera marina L.) is the dominant seagrass species, and several studies have found that eelgrass is effective at taking up inorganic carbon and maybe carbon-limited, potentially increasing uptake potential in the future. However, irradiance levels vary throughout a day and can therefore influence rates of carbon uptake and release through the relative rates of photosynthesis and respiration. Eelgrass meadows vary in terms of meadow size, shoot density and morphology, and water residence time which could affect rates of carbon uptake of eelgrass meadows and their influence on localized water chemistry. We conducted a series of mesocosm experiments manipulating pCO2, irradiance, and leaf area index (LAI)to assess how these factors interact and contribute to OA variability in the nearshore environment.

Download or read book Effects of Eelgrass Zostera Marina Habitat Fragmentation on the Epifaunal Community in San Diego Bay USA written by Danielle Healey and published by . This book was released on 2005 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ecological Life History of Zostera Marina L eelgrass in Puget Sound Washington written by Ronald C. Phillips and published by . This book was released on 1972 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluating Eelgrass Zostera Marina Site Quality by the Settlement Performance and Survival of a Marine Fish written by and published by . This book was released on 2011 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The quantity of suitable habitat can be simply defined by the distribution and abundance of organisms, but it is the quality of the habitat that may have more direct demographic consequences. Habitat quality is best assessed by determining demographic rates and the performance of the focal species residing within a habitat. Using this framework, I used two demographic rates (settlement and survival) and two performance measures (growth and condition) of the giant kelpfish (Heterostichus rostratus) to evaluate whether eelgrass (Zostera marina) habitat quality varies spatially (i.e., site quality) within San Diego Bay, CA. Seven sites were selected that encompass the northern and central areas of the bay. Settlement was estimated bi-weekly from May-July 2009 with artificial seagrass units (ASUs) and standard monitoring units for the recruitment of fishes (SMURFs). Eelgrass habitat complexity (shoot height and density) was measured at each site, and three complexity treatments were replicated with ASUs in large mesocosms to estimate survival of giant kelpfish after exposure to kelp bass (Paralabrax clathratus) as predators. Growth and condition were derived from juvenile giant kelpfish collected from sites two months after the settlement period. Growth and condition were estimated from otolith daily growth increments and total lipid content, respectively. Settlement, growth, and condition were evaluated using a multivariate approach to provide an assessment of habitat quality among sites. Combined with habitat-dependent survival from predators in laboratory trials that reflected site-specific habitat attributes, sites were ranked along a gradient of habitat quality. The multivariate analysis of site quality based on demographic and performance variables was then overlaid with a similar analysis of environmental variables. Environmental variables that would serve as proxies for habitat quality were not concordant with the suite of demographic and performance variables used to differentiate site quality. Consequently, a multivariate approach using demographic rates and individual performance is the most appropriate method to evaluate habitat quality, whether among different habitats or among sites with the same habitat.

Download or read book Quantification and Spatial Analysis of Seagrass Landscape Structure Through the Application of Aerial and Acoustic Remote Sensing written by Jeffrey Peter Barrell and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mapping the Spatial Temporal Variation in Ras Ghanada Seagrass Meadows and Sand Shoals Between 1996 2006 2012 written by Ryan Brookbank and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Seagrass meadows offshore Ras Ghanada, as elsewhere, are an important component to the ecosystem providing numerous benefits to both aquatic and human life. This work focused on mapping the spatial and temporal distribution of seagrass meadows offshore Ras Ghanada using aerial photography acquired in 1996 and high-resolution satellite images captured in 2006 and 2012. The movements of sand shoals were also tracked, so as to further explain the dynamics of this ecosystem, as it is the area between the shoal crests that hosts the best developed seagrass meadows. The natural limiting factor for seagrass on the Ras Ghanada coastal shelf seems to be the fact that they cannot inhabit the (mobile) crests of the sand shoals, but rather, are restricted to the (more stable) sands of the shoal troughs. In the considered time period, both sand shoals and seagrass meadows migrated predominantly in a southeastern direction. The changes of seagrass that occurred in this study occurred on a fairly rapid timescale, in such that they were able to come back when there was disturbance as long as they had available habitat to move into. Furthermore, although seagrass cover declined by 3.4% from 1996 2012, there was a greater increase than decline in the areal coverage of seagrass post-Khalifa port construction in 2010. If sediments offshore Ras Ghanada can remain stable and the waters are not polluted by further construction, seagrasses should continue to thrive in the future.