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Despite holding substantial ecological value, wetlands in the United States have experienced a significant decline in both area and function over the past century with the majority of freshwater wetland ...
Citation Citation
- Title:
- Landsat-based monitoring of annual wetland change in the main-stem Willamette River floodplain of Oregon, USA from 1972 to 2012
- Author:
- Fickas, Kate, Colleen
Despite holding substantial ecological value, wetlands in the United States have experienced a significant decline in both area and function over the past century with the majority of freshwater wetland loss attributed to agricultural conversion. Agriculture is the second largest industry in the State of Oregon and the State places substantial emphasis in its land use planning goals on the preservation of agricultural land. Oregon’s Willamette Valley accounts for the majority of agricultural output with 53% of the valley bottom classified as agricultural land. Additionally, the valley houses 70% of the state's population. The valley was once comprised of extensive wet prairies and abundant riparian forests along the Willamette River floodplain, but native ecosystems have been reduced to a fraction of their original distribution since Euro-American settlement in the mid 1800s. The few wetlands that remain are at high risk to loss and degradation from agricultural activity. Following national wetland conservation policies, Oregon has since attempted to monitor and regulate losses due to disturbance and modification of the State's remaining wetlands through a "no-net-loss" policy aiming to decrease wetland losses and replace disturbed wetlands through mitigation. The National Wetlands Inventory (NWI) was designed to produce detailed maps and status reports of the characteristics and extent of the nation's wetlands and help determine the efficacy of no-net-loss policy implementation on the nation’s wetlands. In some cases, the NWI has been found to have low categorical and spatial accuracy and coarse temporal resolution, with some maps over two decades old. Although Landsat satellite imagery was originally found to lack the needed spatial resolution for classification detail and wetness designation that aerial photography provided, Landsat has 40 years of freely available, high quality annual imagery and should be explored for use in annual wetland change detection. Our objectives were to: (1) Quantify and characterize spatial and ecological trends in annual wetland change through gain, loss, and conversion in the Willamette Valley; (2) Evaluate the effect of the no-net-loss federal wetland conservation policy change enacted in 1990 on trends in net wetland area; and (3) Describe a new methodology that reaches back through the over 40-year Landsat archive to map fine scale wetland and related land-use changes from 1972-2012. We used annual Landsat MSS and TM/ETM+ images from 1972 to 2012 to manually interpret loss, gain, and type conversion of wetland area in the two-year inundation floodplain of the Main-Stem Willamette River using TimeSync, Google Earth, and ArcMap. By creating Tasseled Cap Brightness, Greenness, and Wetness indices for MSS data that visually match TM/ETM+ Tasseled Cap images, we were able to construct a complete and consistent annual time series and utilize the entire Landsat archive. Additionally, with an extended time series, we were able to compare trends of annual net change in wetland area before and after the no-net-loss policy established under Section 404 of the Clean Water Act in 1990. We found that wetlands experienced annual loss, gain, and type conversion across the entire study period. Vegetated wetlands (emergent and riparian wetlands) experienced a 314 ha net loss of wetland area across the 40 year study period whereas non-vegetated wetlands (lacustrine and riverine wetlands) experienced a 393 ha net gain. All wetland types combined saw a 79 ha net increase in wetland area across the full study period. The majority of both gain and loss in the study area was attributed to and from agricultural conversion followed by urban land use. Time series analysis of the rate of change of net wetland area was calculated using the Theil-Sen (TS) Slope estimate analysis. For annual change of wetland area before and after 1990 no-net-loss policy implementations, the rate of annual wetland area lost slowed for riparian wetlands and reversed into trends of annual net gain in area of emergent wetlands. The rate of annual net area gained for lacustrine wetlands was slowed post-policy. Accuracy assessment of land use change polygons in the field was only able to capture 12% of our interpretations due to access restrictions associated with private land. In spite of a low sample size (n=45), overall accuracy of land use classification through wetland change polygons was at 80%. This accuracy increased to 91.1% when land use classes were aggregated to either wetland or upland categories, indicating that our methodology was more accurate at distinguishing between general upland and wetland than finer categorical classes.
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Seafloor lithologic maps have been widely used to identify conservation sites. In this study, a lithologic interpretation of Oregon's territorial seafloor was created as an interim product in response ...
Citation Citation
- Title:
- Mapping and lithologic interpretation of the Territorial Sea, Oregon
- Author:
- Agapito, Melinda T.
Seafloor lithologic maps have been widely used to identify conservation sites. In this study, a lithologic interpretation of Oregon's territorial seafloor was created as an interim product in response to the need for a comprehensive lithologic map that will be used in the identification, evaluation and design of marine reserves in Oregon. While future multibeam mapping of the Oregon Territorial Sea will likely replace this product in the next few years, the ground truth data from which the map is constructed will continue in use in future efforts. This mapping project utilized a classical geologic approach aided by GIS technology in which all relevant thematic geologic layers were applied to interpret patterns of seafloor lithology. The discovery of approximately 9,600 NOS bottom samples from the National Ocean Service (NOS) historic hydrographic smooth sheet archives has tremendously improved upon the original sample dataset (305 bottom samples) used in previous characterization of Oregon's territorial seabed. Supplementing the NOS bottom samples, other existing datasets including historic kelp distribution (used as proxy for rock), a triangulated irregular network (TIN) surface model derived from bathymetric soundings, rock outcrops digitized from 0.5 meter aerial photos, subsurface structure, and the adjacent onshore Oregon digital geologic map were used. While the collection of smooth sheet data from historic surveys utilized leadline sampling techniques and traditional navigation methods such as three-point sextant positioning, it was observed that the typical positional error averaged ~28 meters relative to contemporary aerial photography where comparison was possible. GIS software was used for simultaneous display of varied thematic layers, qualitative interpretation, quantitative accuracy assessment, and density mapping processes in this project. This current mapping effort showed that the NOS "smooth sheet" data collected from 1858 to 1958 compares well with modern data and that the NOS datasets and methods are able to capture the general outlines of rocky outcrops particularly in shallow areas. The territorial lithologic map shows a reasonable overall accuracy of 64 % relative to existing habitat interpretation of rocky reefs based on high-resolution multibeam data. Furthermore, the NOS bottom samples provide an opportunity to map additional sediment types that are not represented in the existing Surficial Geologic Habitat (SGH) map of the territorial sea. Finally, a companion product to the maps, a composite density map was created from the underlying datasets (kelp, bathymetry and bottom samples) to represent the spatial variation in data quality and quantity used in the interpretation of seafloor lithology. It is anticipated that the data obtained from this study will serve as a useful tool for scientific investigation and management efforts such as the ocean zoning in the nearshore region of the Oregon coast, which includes the upcoming designation and evaluation of marine reserves.
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53. [Article] Re‐establishment of the native oyster, Ostrea conchaphila, in Netarts Bay, Oregon, USA
Olympia oysters, “Ostrea conchaphila,” were once common along the west coast of North America. A popular delicacy, native oyster populations began to decline in the late 1800’s due to over‐harvest, degraded ...Citation Citation
- Title:
- Re‐establishment of the native oyster, Ostrea conchaphila, in Netarts Bay, Oregon, USA
- Author:
- Archer, Pamela Emily
Olympia oysters, “Ostrea conchaphila,” were once common along the west coast of North America. A popular delicacy, native oyster populations began to decline in the late 1800’s due to over‐harvest, degraded water quality, and habitat loss. Interest in re‐establishing the native oyster in a small Oregon estuary, Netarts Bay, culminated in a partnership among The Nature Conservancy, the National Oceanic and Atmospheric Administration, the Oregon Watershed Enhancement Board, and Oregon State University. This study was designed to assess the reestablishment progress of the Olympia oyster restoration in Netarts Bay along with subsequent impacts of the restoration on eelgrass (“Zostera marina”), an important estuarine species. Two brood years (2005 & 2006) of cultch, consisting of O. conchaphila set on clean “Crassostrea gigas” shell substrate, were outplanted within an extensive, relatively uniform eelgrass bed. Cultch was placed in two experimental locations to determine the effect of cultch cover on native oyster survival, growth, and eelgrass abundance. The percent cover of cultch varied among treatments: “control” (no cultch), “low” (4% cultch cover), “medium” (11% cultch), and “high” (19% cultch). Research objectives were: (1) determination of O. conchaphila density, growth, and reproduction; and (2) quantification of the response of ”Z. marina” abundance and reproduction to cultch cover. Results from 2007 demonstrated that Olympia oysters were capable of growth, reproduction, and recruitment within their former habitat. Cultch cover within treatments did not change throughout the summer and there was minimal shell export out of the experimental location. Oyster size increased from March‐September, 2007: the mean size of the 2005 brood year increased by 10.5 mm, while the 2006 brood year increased by 16.2 mm. Sperm and larvae were found in individuals from both brood years, indicating that oysters were reproductively active. Declines in eelgrass mean percent leaf cover and shoot density were observed with increasing cultch cover. The mean eelgrass percent leaf cover was 15‐22% lower and shoot density was 27‐36% lower in high treatment (19% cultch) plots than in control plots. There were no discernable patterns in the eelgrass response variables of flowering shoot count, blade length, or blade width. The medium treatment (11% cultch), in which oyster densities were statistically similar to the high treatment (19% cultch), did not have statistically significant impacts on eelgrass percent cover or shoot density. We recommend continued testing of the medium treatment (11% cultch), as well as other cultch densities, such as a 50% cultch treatment. Additional monitoring will be needed to determine what, if any, long‐term impacts occur to the eelgrass bed. We also recommend long‐term monitoring of both oysters and eelgrass beds to detect any additional changes at the re‐establishment site.
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Coral reef ecosystems are the oceanic equivalent of tropical rainforests, in terms of biodiversity. The estimated 1,037,000 square kilometers worldwide of reef provide habitat for over one million species ...
Citation Citation
- Title:
- An evaluation of the likelihood of successful implementation of the long term coral reef monitoring program on the Commonwealth of the Northern Mariana Islands
- Author:
- Kylstra, Pam
Coral reef ecosystems are the oceanic equivalent of tropical rainforests, in terms of biodiversity. The estimated 1,037,000 square kilometers worldwide of reef provide habitat for over one million species of plants and animals (Hinrichsen, 1997). Coral reefs are important to the economy of coastal nations because of the fisheries and tourism industries they support. Reef ecosystems provide a host of important natural services such as storm buffering, a protein source for islanders, breeding and nursery grounds for marine organisms, water filtration and a source of biomedically important products. Coral reef areas also have aesthetic and intrinsic value that is reason enough to protect them. Coral reefs are also among the most endangered ecosystems on Earth. Naturally occurring disturbances are compounded by the impacts of anthropogenic disturbance. Factors that threaten the health of coral reef ecosystems on a global scale include global warming, the continuing increase in coastal populations and associated impacts such as nutrient pollution, sedimentation and runoff, coral mining, ship groundings, overfishing, and recreational overuse. Globally, coastal areas accommodate about 60% of Earth's human population. A significant portion of the population lies within tropical regions. This population pressure subjects coral reef environments to effects of increased competition for coastal resources, increased coastal pollution and problems related to coastal construction. The synergistic effect of stressors has been the irreversible degradation worldwide of 10% of reefs and another 60% in critical condition leaving, only 30% as stable (Wilkinson, 1993). The coral reefs of the Commonwealth of the Northern Mariana Islands (CNMI) are a good example of how the combination of increasing human population and the associated environmental pressure has resulted in degradation of the reef ecosystem. The CNMI has undergone significant change in economic and population growth within the past decade. To accommodate the rapid and continuing development of the tourism industry, numerous golf courses and resort hotels have been constructed on Saipan. The population of Saipan has increased over 30% in the last ten years. Currently, the local/resident population is 60,000 while the visitor population is 750,000 per year. This rapid growth has had serious ecological consequences. Coral roads have been converted to four lane highways and infrastructure such as septic tank systems has not been improved to meet higher demand. More and more development projects have been proposed without adequate consideration of environmental impacts. Conflicts over the use and conservation of marine and watershed resources continue to arise. The continuing decline of reef systems globally and in specific areas like the CNMI, highlights the need for effective methods of assessing change in nearshore ecosystems. This paper explores the ways that coral reef monitoring can provide information about reef health that serves to affect positive changes in management strategies for marine systems. Using a criteria drawn from case study comparisons of ongoing, well established coral monitoring programs and evaluation framework proposed by policy analysts Using criteria drawn from case, the Long Term Marine Monitoring Program (LTMMP) on Saipan, CNMI is evaluated. The evaluation provides insight about coral monitoring plan components that are essential to the effectiveness of coral reef monitoring programs. This report is an outgrowth of an internship the author performed with the CNMI Division of Environmental Quality on the island of Saipan from June to October of 1997. The University of Oregon Micronesia and South Pacific Program and the government of the Commonwealth of the Northern Mariana Islands (CMNI) sponsored the internship project. The objectives of the internship were to assist in field data collection and continuing development of the ongoing Long Term Marine Monitoring Plan (LTMMP) Assist and instruct Marine Monitoring Team (MMT) members in basic computer skills, understanding of data applicability, management, interpretation and analysis, basic biology and resource management techniques as it relates to marine monitoring work Facilitate inter-governmental agency coordination of marine monitoring activities Assess likelihood of success and explore challenges facing Saipan in implementation of the monitoring program This report first describes functions and services provided by coral reefs and an introduction to the stresses and disturbances that compromise the health of reef systems globally. Using examples from case studies of established marine monitoring programs, this report considers how effective monitoring can reveal changes in the reef system over time, enabling conservation measures to be taken. It then turns to the island of Saipan and briefly describes the environmental and socio-economic framework within which the coral reef related provisions of the CNMI coastal management program are considered. This background information is used to evaluate the Long Term Marine Monitoring Plan currently in place on the CNMI. This evaluation provides insight into the challenges to implementation of coral reef monitoring plans and recommendations for improvements in the LTMMP on Saipan.
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Interannual variability of Humboldt squid (Dosidicus gigas) occurrence in the northern California Current System is largely unknown. In Oregon, the distribution of this versatile predator and what is influencing ...
Citation Citation
- Title:
- A cooperative effort to track Humboldt squid invasions in Oregon
- Author:
- Chesney, Tanya A.
Interannual variability of Humboldt squid (Dosidicus gigas) occurrence in the northern California Current System is largely unknown. In Oregon, the distribution of this versatile predator and what is influencing their range expansion from Mexico is poorly understood due to the recent nature of their "invasion" and a lack of monitoring. Humboldt squid are large predators that have the potential to affect ecosystem structure and fisheries because of their high-energy demands and ability to exploit a variety of oceanographic conditions and prey sources. Developing baseline distribution information is a critical first step to assess their potential ecological, social, and economic impacts, and to develop models to predict future range expansion. This study has two main objectives: (1) to document where and when Humboldt squid have been present in Oregon through cooperative fisheries research, and (2) to correlate the sightings with oceanographic conditions using a geographic information system (GIS) and species distribution modeling (SDM). I conducted 54 interviews with local fishermen and aggregated their squid sightings with available fishery-independent survey and fishery-dependent observer data from the National Marine Fisheries Service. I compiled a total of 339 Humboldt squid sightings, reported for the years 2002-2011 from the Oregon coast to 131° west longitude. Correlation analyses were performed for Humboldt squid sightings and sea surface temperature (SST), chlorophyll a content (chla), sea surface height anomalies (SSH), dissolved oxygen at 30 m depth (30 m DO), and sea surface salinity (SSS) using a GIS, nonparametric multiplicative regression (NPMR) habitat modeling, and maximum entropy modeling (Maxent). Results indicate that oceanographic conditions have the potential to influence Humboldt squid occurrence, and in Oregon, sightings vary temporally and spatially. Combining the sightings from fishermen and scientific surveys greatly enhanced the spatial extent of the data. Humboldt squid were most frequently observed between 124.4°W and 125°W in proximity to the shelf-break at the 200 m isobath, with peak sightings (116) recorded in 2009 and the fewest (6) reported in 2003 and 2011. The highest occurrence of Humboldt squid were observed at a SST of 10.5-13.0°C, 0.26-3.0 mg m⁻³ chla content, -4.0-1.0 m SSH anomalies, 32.2-32.8 psu SSS, and at 3-4.5 ml L⁻¹ and 6-7 ml L⁻¹ 30 m depth DO. Maps of estimated likelihood of occurrence generated by NPMR were consistent with overlayed observations from fishermen, which were not used in the model because they were limited to presence-only information. An interdisciplinary approach that incorporates cooperative fisheries research and ecosystem-based management is necessary for monitoring Humboldt squid in Oregon. Traditional methods are insufficient because Humboldt squid are data-poor, highly migratory, and are main predators of many commercially important fisheries in Oregon. Based on my findings, sightings recorded by fishermen covered a much larger area over a longer time frame than the scientific survey and observer data, and excluding their knowledge would have led to a different interpretation of Humboldt squid distribution and environmental tolerances. Although there is uncertainty in the data from potential map bias or misidentification of smaller Humboldt squid, incorporating sightings from fishermen with traditional fisheries research increases the quantity and quality of information. Cooperative monitoring for Humboldt squid could include training in species identification and sea condition reporting in logbooks. Future "invasions" are likely, and more eyes on the water will improve our understanding of the behavior and impacts of Humboldt squid on coastal resources.