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USGS2005

Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a Refuge and provide long range guidance and management direction to achieve Refuge purposes. Sand Lake National Wildlife Refuge (NWR), located 27 miles northeast of Aberdeen, South Dakota, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for Sand Lake NWR must contain an analysis of expected effects associated with current and proposed Refuge management strategies. Special interest groups and local residents often criticize a change in Refuge management, especially if there is a perceived negative impact to the local economy. Having objective data on income and employment impacts may show that these economic fears are drastically overstated. Quite often, residents do not realize the extent of economic benefits a Refuge provides to a local community; yet at the same time overestimate the impact of negative changes. Spending associated with Refuge recreational activities such as wildlife viewing and hunting can generate considerable tourism activity for the regional economy. Refuge personnel typically spend considerable amounts of money purchasing supplies in the local lumber and hardware stores, repairing equipment and purchasing fuel at the local service stations, as well as reside and spend their salaries in the community. The purpose of this study was to provide the economic analysis needed for the Sand Lake NWR CCP by evaluating the regional economic impacts associated with the Sand Lake NWR Draft CCP management strategies. For Refuge CCP planning, an economic impact analysis describes how current (No Action Alternative) and proposed management activities (alternatives) affect the local economy. This type of analysis provides two critical pieces of information: (1) it illustrates a refuge’s contribution to the local community; and (2) it can help in determining whether local economic effects are or are not a real concern in choosing among management alternatives. Sand Lake NWR is currently managed to improve and maintain habitat for nesting and resting waterfowl and other migratory birds, such as diving and puddle ducks, geese, grebes, herons, egrets, gulls, and terns. There are three alternatives evaluated in the draft CCP. Alternative 1, the No Action alternative, would continue Refuge management at current levels and would not involve extensive restoration of cropland, grassland, and wetland habitat or improvements to roads, interpretive, and administrative facilities. No new funding or staff levels would occur and programs would follow the same direction, emphasis, and intensity as they do at present. Alternative 2 would maximize the biological potential of the refuge for species of grassland-nesting birds. This would be accomplished through intense management of upland habitat for nesting migratory birds, minimal management for resident species, and minimization of public use that may interfere with migratory bird production. The third alternative takes an integrated approach, with management practices that would serve to maximize the biological potential of Sand Lake for migratory birds. This report first provides a description of the local community and economy near the Refuge. An analysis of current and proposed management strategies that could affect the local economy is then presented. The Refuge management activities of economic concern in this analysis are Refuge personnel staffing and Refuge spending within the local community, and spending in the local community by Refuge visitors.

Sand Lake National Wildlife Refuge↗

USGS2005

Monitoring-well network and sampling design for ground-water quality, Wind River Indian Reservation, Wyoming

The Wind River Indian Reservation, located in parts of Fremont and Hot Springs Counties, Wyoming, has a total land area of more than 3,500 square miles. Ground water on the Wind River Indian Reservation is a valuable resource for Shoshone and Northern Arapahoe tribal members and others who live on the Reservation. There are many types of land uses on the Reservation that have the potential to affect the quality of ground-water resources. Urban areas, rural housing developments, agricultural lands, landfills, oil and natural gas fields, mining, and pipeline utility corridors all have the potential to affect ground-water quality. A cooperative study was developed between the U.S. Geological Survey and the Wind River Environmental Quality Commission to identify areas of the Reservation that have the highest potential for ground-water contamination and develop a comprehensive plan to monitor these areas. An arithmetic overlay model for the Wind River Indian Reservation was created using seven geographic information system data layers representing factors with varying potential to affect ground-water quality. The data layers used were: the National Land Cover Dataset, water well density, aquifer sensitivity, oil and natural gas fields and petroleum pipelines, sites with potential contaminant sources, sites that are known to have ground-water contamination, and National Pollutant Discharge Elimination System sites. A prioritization map for monitoring ground-water quality on the Reservation was created using the model. The prioritization map ranks the priority for monitoring ground-water quality in different areas of the Reservation as low, medium, or high. To help minimize bias in selecting sites for a monitoring well network, an automated stratified random site-selection approach was used to select 30 sites for ground-water quality monitoring within the high priority areas. In addition, the study also provided a sampling design for constituents to be monitored, sampling frequency, and a simple water-table level observation well network.

Scientific Investigations Report↗

USGS2023

Silver carp herding: A telemetry evaluation of efficacy and implications for design and application

Removal of invasive Silver Carp Hypophthalmichthys molitrix is a primary control action in North America. Strong avoidance responses to underwater sound and electricity have been shown to facilitate herding and mass removal of these fish. We conducted a telemetry study on a closed population of Silver Carp (i.e., 10 telemetered fish) to assess fine-scale movement responses to herding stimuli. Two herding boats traveled along bank-to-bank transects through the study area (longitudinal progression rate = 0.37 m/s) emitting sound and electricity (“combination technique”) or no added stimuli (“control”). The combination technique was most effective in terms of increasing fish presence (2.2 x the control) in the refuge-zones when herding had concluded and effective range (i.e., fish reaction distance; 1.6 x the control) relative to the herding boats. Fish median (~1 m/s) and maximum (~2 m/s) swimming velocity was relatively stable across fixed effects, except for the negative influence of water depth on maximum velocity. Water depth also exhibited a negative effect on fish reaction distance. Our results suggest effective range of the combination technique was conservatively 200 m (~20 dB re 1 μPa > ambient level) when accounting for water depth in the study area. Herding deployments less than 1 m/s (longitudinal progression) could control fish passing and maintain fish movements towards an intended location. Information provided herein can serve to assist planning, design, and application of herding efforts used to manage, control, and remove these invasive fish.

Kentucky↗

USGS2014

Natural flow regimes of the Ozark-Ouachita Interior Highlands region

Natural flow regimes represent the hydrologic conditions to which native aquatic organisms are best adapted. We completed a regional river classification and quantitative descriptions of each natural flow regime for the Ozark–Ouachita Interior Highlands region of Arkansas, Missouri and Oklahoma. On the basis of daily flow records from 64 reference streams, seven natural flow regimes were identified with mixture model cluster analysis: Groundwater Stable, Groundwater, Groundwater Flashy, Perennial Runoff, Runoff Flashy, Intermittent Runoff and Intermittent Flashy. Sets of flow metrics were selected that best quantified nine ecologically important components of these natural flow regimes. An uncertainty analysis was performed to avoid selecting metrics strongly affected by measurement uncertainty that can result from short periods of record. Measurement uncertainties (bias, precision and accuracy) were assessed for 170 commonly used flow metrics. The ranges of variability expected for select flow metrics under natural conditions were quantified for each flow regime to provide a reference for future assessments of hydrologic alteration. A random forest model was used to predict the natural flow regimes of all stream segments in the study area based on climate and catchment characteristics, and a map was produced. The geographic distribution of flow regimes suggested distinct ecohydrological regions that may be useful for conservation planning. This project provides a hydrologic foundation for future examination of flow–ecology relationships in the region. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Arkansas, Missouri, Oklahoma↗

USGS2016

Community disruptions and business costs for distant tsunami evacuations using maximum versus scenario-based zones

Well-executed evacuations are key to minimizing loss of life from tsunamis, yet they also disrupt communities and business productivity in the process. Most coastal communities implement evacuations based on a previously delineated maximum-inundation zone that integrates zones from multiple tsunami sources. To support consistent evacuation planning that protects lives but attempts to minimize community disruptions, we explore the implications of scenario-based evacuation procedures and use the California (USA) coastline as our case study. We focus on the land in coastal communities that is in maximum-evacuation zones, but is not expected to be flooded by a tsunami generated by a Chilean earthquake scenario. Results suggest that a scenario-based evacuation could greatly reduce the number of residents and employees that would be advised to evacuate for 24–36 h (178,646 and 159,271 fewer individuals, respectively) and these reductions are concentrated primarily in three counties for this scenario. Private evacuation spending is estimated to be greater than public expenditures for operating shelters in the area of potential over-evacuations ($13 million compared to $1 million for a 1.5-day evacuation). Short-term disruption costs for businesses in the area of potential over-evacuation are approximately $122 million for a 1.5-day evacuation, with one-third of this cost associated with manufacturing, suggesting that some disruption costs may be recouped over time with increased short-term production. There are many businesses and organizations in this area that contain individuals with limited mobility or access and functional needs that may have substantial evacuation challenges. This study demonstrates and discusses the difficulties of tsunami-evacuation decision-making for relatively small to moderate events faced by emergency managers, not only in California but in coastal communities throughout the world.

Natural Hazards↗

USGS2006

The Pu'u ‘O’o‐Kupaianaha eruption of Kilauea

Kilauea is nearing the 10th year of its most voluminous rift zone eruption in the last 2 centuries. Lava flows have covered 75 km 2 to depths as great as 25 m and have added almost 1.2 km 2 of new land to the island. These flows have devastated downslope communities and have provided a painful tutorial for local government in planning for and living with volcanic hazards [ Heliker and Wright , 1991]. At the same time, the accessibility and longevity of this eruption have provided a unique opportunity for quantitative studies requiring long‐term observations. This article briefly summarizes these studies, which are directed at a better understanding of eruption mechanics, lava‐flow field emplacement, and the plumbing system of Kilauea.

Hawaii↗

USGS2016

Salmon and steelhead in the White Salmon River after the removal of Condit Dam–Planning efforts and recolonization results

Condit Dam, at river kilometer 5.3 on the White Salmon River, Washington, was breached in 2011 and completely removed in 2012. This action opened habitat to migratory fish for the first time in 100 years. The White Salmon Working Group was formed to create plans for fish salvage in preparation for fish recolonization and to prescribe the actions necessary to restore anadromous salmonid populations in the White Salmon River after Condit Dam removal. Studies conducted by work group members and others served to inform management decisions. Management options for individual species were considered, including natural recolonization, introduction of a neighboring stock, hatchery supplementation, and monitoring natural recolonization for some time period to assess the need for hatchery supplementation. Monitoring to date indicates that multiple species and stocks of anadromous salmonids are finding and spawning in the now accessible and recovering habitat.

Washington↗

USGS2017

Multidirectional abundance shifts among North American birds and the relative influence of multifaceted climate factors

Shifts in species distributions are major fingerprint of climate change. Examining changes in species abundance structures at a continental scale enables robust evaluation of climate change influences, but few studies have conducted these evaluations due to limited data and methodological constraints. In this study, we estimate temporal changes in abundance from North American Breeding Bird Survey data at the scale of physiographic strata to examine the relative influence of different components of climatic factors and evaluate the hypothesis that shifting species distributions are multidirectional in resident bird species in North America. We quantify the direction and velocity of the abundance shifts of 57 permanent resident birds over 44 years using a centroid analysis. For species with significant abundance shifts in the centroid analysis, we conduct a more intensive correlative analysis to identify climate components most strongly associated with composite change of abundance within strata. Our analysis focus on two contrasts: the relative importance of climate extremes vs. averages, and of temperature vs. precipitation in strength of association with abundance change. Our study shows that 36 species had significant abundance shifts over the study period. The average velocity of the centroid is 5.89 km·yr −1 . The shifted distance on average covers 259 km, 9% of range extent. Our results strongly suggest that the climate change fingerprint in studied avian distributions is multidirectional. Among 6 directions with significant abundance shifts, the northwestward shift was observed in the largest number of species ( n = 13). The temperature/average climate model consistently has greater predictive ability than the precipitation/extreme climate model in explaining strata‐level abundance change. Our study shows heterogeneous avian responses to recent environmental changes. It highlights needs for more species‐specific approaches to examine contributing factors to recent distributional changes and for comprehensive conservation planning for climate change adaptation.

Global Change Biology↗

USGS1970

Taunton River basin

The Taunton River, emptying into an arm of Narragansett Bay at Fall River, drains 528 square miles of interior southeastern Massachusetts. The Taunton River basin is separated from the basins of short streams draining to the coast by low divides on the east, south, and southwest. On the west and north, the basin is bordered by the Ten Mile, Charles, Neponset, and Weymouth River basins. Principal tributaries of the lower Taunton River are Segreganset, Threemile, Mill, Assonet, Nemasket, and Winnetuxet Rivers. The upper part of the basin is drained by the Canoe, Wading, and Rumford Rivers which empty into Mill and Threemile Rivers and by the Matfield and Town Rivers which unite to form the Taunton River. This report presents in tabular form selected records of wells, test wells, and borings collected during a study of the basin from 1966 to 1968 in cooperation with the Massachusetts Water Resources Commission, and during earlier studies. This report is released in order to make available to the public and to local, state, and federal agencies basic ground-water information that may aid in planning water-resources development. Basic records contained in this report will complement an interpretative report on the Taunton River basin to be released at a later date.

Massachusetts↗

USGS2001

Citizen knowledge and perception of black-tailed prairie dog management: Report to respondents

What do citizens know about black-tailed prairie dogs, and where do they get their information? When management decisions need to be made regarding an animal such as the black-tailed prairie dog, an understanding of the species and its relationship to humans is necessary. This includes knowing the biology of the animal, where it lives, and how it interacts with other animals. But it is equally important for those making decisions about the species to understand citizens’ knowledge and perceptions so managers can effectively communicate with the public and help the public participate in planning and decision making activities. Unfortunately, what is known about public knowledge, perception, and preferences concerning prairie dog management is limited to data from only a few areas. This study attempts to answer the question: What do people in the short-grass prairie region of the United States know and think about black-tailed prairie dogs? In the summer of 2000, we sent a survey by mail to citizens of rural, urban, and suburban counties in the short-grass prairie region of the United States. This area includes all or part of 11 states: Arizona, Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming (see Figure 1, p. 4). A total of 1933 citizens completed the survey for a 56% response rate (Table 1). This report provides a summary of the answers for all the questions in the survey. (Extra copies of this report can be downloaded from our website: http://www.mesc.usgs.gov/seias.) The results show that although people do not believe prairie dogs are a big environmental issue, they favor a balanced approach when dealing with such problems. When asked about their views on environmental policy, respondents reported being more conservative than liberal: 40% reported slightly conservative or conservative environmental views, 24% reported moderate environmental views, and 19% reported slightly liberal or liberal environmental views. Ninteen percent (19%) said they did not know or had not thought about their environmental values. When asked how important black-tailed prairie dogs are compared to other environmental problems, 69% said they are less important than other issues or not an issue at all. Thirty one percent (31%) said prairie dogs are about the same or more important than other issues.

Open-File Report↗

USGS2002

Values and attitudes of National Wildlife Refuge managers and biologists; Report to respondents

The issues affecting natural resource management, the society in which natural resource management occurs, natural resource agency personnel, and the publics they serve have changed in recent decades. Previous studies of Refuge professionals in the U.S. Fish and Wildlife Service (Service) have revealed that employees lack strong commitment to the current organizational structure, were frustrated with the lack of communication within the agency and felt there was a need for strong leadership (PEER 1998, 1999). These results prompted the authors to have further questions about refuge management in the Fish and Wildlife Service. What do employees value about their agency? Is there a difference in values between refuge managers and biologists and if so, what are those differences and what influences those differences? Recently, there has been speculation that changes in society and the demographic makeup of natural resource professionals has caused a paradigm shift for natural resource management (Ballard 2002; Brown and Harris 1992abc, 2000; Maestas 2002). But, there has been little work assessing the values, attitudes or behaviors of natural resource professionals to determine if a paradigm shift is really occurring. Most of the work in the field of values, attitudes, and behaviors has focused on the public and their interaction with environmental management issues; such as, endangered species management (Lybecker et al. 2002; Solomon 1998), human-wildlife conflict (Baker and Fritsch 1997; Chase et al. 1999; Jones and Thomas 1999; Mankin et al. 1999), changes in hunting or trapping regulations (Loker et al. 1998; Manfredo et al. 1999; Whittaker and Torres 1998), or management of public lands (Badalamente et al. 2000). The purpose of this study was to gain a better understanding of the values and attitudes refuge employees have toward natural resources. The goal was to survey National Wildlife Refuge professionals about natural resource management. We surveyed Refuge Managers and Refuge Biologists (n=480) at staffed U.S. National Wildlife Refuges in the contiguous 48 states in the fall of 200 1. We used a modified Dillman design, resulting in a 68% response rate. The objectives of this study were to (1) determine and compare the environmental values of refuge managers and biologists at selected refuges and (2) assess attitudes about various institutional factors (public involvement and planning). Analyses of data revealed that these managers and biologists did not differ substantially in terms of their environmental values. Refuge professionals were supportive of public involvement in planning and management, but hoped to maintain management authority throughout the process. Professionals were skeptical concerning the applicability of long term planning, but were generally supportive of the planning process. Attitudes toward the Service were conflicting: professionals felt that the Service needed to provide better leadership and direction, but that the Refuge System needed to assert its autonomy and independence from the rest of the Service.

Open-File Report↗

USGS1955

Quality of water of the Colorado River, 1925-40

The study of the quality of water of the Colorado River and its tributaries has been a continuing one since 1925. The data so obtained have been useful in the planning and construction of dams and reservoirs, the utilization of the water within the basin, and in planning the economy of areas outside of the basin, partially or wholly dependent on the diversion or importation of water from the Colorado River or its tributaries. Much chemical quality data of the Colorado River and its tributaries collected during the period from 1925 to 1940 have not been published in detail. The purpose of this report is to make available for consultation and ready reference those previously unpublished data collected for the period 1925 to 1940, mainly between 1930 and 1940. Included among these data are many detailed chemical analyses of composites of daily samples and single samples of the Colorado River and its main tributaries and less detailed analyses of many other samples. In a few instances, for continuity of the record, analyses are included that have been published in Survey reports. Discussions of the quality of water of the Colorado River basin either in published reports or in mimeograph form are available; therefore, this report will include only tabulated data. Data obtained for the period 1925 to 1930 for the most part were published in three Geological Survey Water-Supply Papers, 596-B, 636-A, and 638-D, all out of print. Summary data for the streams in the Colorado River basin for the period 1925 to 1943 were published in U.S. Geological Survey Water-Supply Paper 970, "Quality of surface waters of the United States, 1943". These summaries consist mainly of annual weighted averages of chemical analyses, dissolved-solids loads, and extremes of dissolved solids and hardness. Analyses of samples from Lake Mead are available in a series of reports, "Lake Mead Density Currents Investigations", by the Bureau of Reclamation /1937 -1940, Vols. I and ll; 1940 -1946; Vol. III/. Data on the suspended sediment in the Colorado River for the period 1925-1941 were published in 1947, in U.S. Geological Survey Water -Supply Paper 998. Since 1940 results of water-quality investigations in the Colorado River basin have been published in the annual U.S. Geological Survey reports, "Quality of surface waters of the United States".

Colorado River↗

USGS1982

An application of a vulnerability index to oil spill modeling in the Gulf of Mexico

An analysis was made of the relative impact to the shoreline of the Gulf of Mexico from proposed Federal Outer Continental Shelf oil and gas leasing activity. An oil spill trajectory model was coupled with a land segment vulnerability characterization to predict the risks to the shoreline. Such a technique allows spatial and temporal variability in oil spill sensitivity to be represented and combined with the likelihood of oil spill contact to specific coastal segments in the study area. Predicted relative impact was greatest along the coastlines of Louisiana, Mississippi, and Alabama. Useful information is provided for environmental impact analysis, as well as oil spill response planning.

Open-File Report↗

USGS1986

Water-resources activities in New York, 1985-86

The U.S. Geologic Survey conducts water-resources investigations and hydrologic data collection in all states to provide the data and understanding needed for optimum use and management of the nation 's surface water and groundwater. This is achieved through jointly funded programs with state, county, municipal, and other Federal agencies. The Geological Survey conducted 37 water resources investigations in New York during 1985-86, several of which are continuous. This report describes each project in terms of problems, objectives, progress to date, and future plans and gives the period of funding, project chief, principal coordinating agency, field location, and completed reports. It also lists all reports resulting from the Survey 's water resources studies in New York during 1982-86. (USGS)

Open-File Report↗

USGS1996

USGS response to an urban earthquake, Northridge '94

The urban centers of our Nation provide our people with seemingly unlimited employment, social, and cultural opportunities as a result of the complex interactions of a diverse population embedded in an highly-engineered environment. Catastrophic events in one or more of the natural earth systems which underlie or envelop urban environment can have radical effects on the integrity and survivability of that environment. Earthquakes have for centuries been the source of cataclysmic events on cities throughout the world. Unlike many other earth processes, the effects of major earthquakes transcend all political, social, and geomorphic boundaries and can have decided impact on cities tens to hundreds of kilometers from the epicenter. In modern cities, where buildings, transportation corridors, and lifelines are complexly interrelated, the life, economic, and social vulnerabilities in the face of a major earthquake can be particularly acute. The 1994 Northridge Earthquake was a major test for parts of what many consider the most earthquake-prepared and best-engineered metropolitan region in the United States. While the combined efforts of concerned professionals at all levels of government, academia, and the private sector have produced significant advances in our knowledge of the causes and potential effects of earthquakes, and of ways to reduce their impact, it remains unfortunately true that actual earthquakes provide important opportunities to test those advances in our knowledge. In the hours and days following the Northridge Earthquake, the four Federal member agencies of the National Earthquake Hazards Reduction Program (NEHRP), the Federal Emergency Management Agency (FEMA), the National Institute for Standards and Technology (NIST), the National Science Foundation (NSF), and the United States Geological Survey (USGS) laid out a detailed plan for collecting, analyzing, archiving, and reporting information that would benefit the Nation in future earthquake hazards reduction efforts. Congress provided a special appropriation to FEMA to carry out this plan and FEMA distributed those funds to the four NEHRP agencies. The USGS was responsible for conducting geophysical and geological investigations in support of the NEHRP Post-earthquake Study. For the past 2 years, the USGS has rigorously pursued over 40 tasks focused on the USGS Northridge Earthquake Mission. This document is a summary report of the USGS findings; additional technical reports on specific USGS tasks are appearing in various scientific journals and USGS publications.

California↗

USGS2012

Assessment of nutrients and suspended sediment conditions in and near the Agassiz National Wildlife Refuge, Northwest Minnesota, 2008–2010

In response to concerns about water-quality impairments that may affect habitat degradation in Agassiz National Wildlife Refuge in northwest Minnesota, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service collected streamflow data, discrete nutrient and suspended- sediment samples, and continuous water-quality data from 2008 to 2010. Constituent loads were estimated for nutrients and suspended sediment using sample data and streamflow data. In addition, a potential water-quality and streamflow monitoring program design was developed for Agassiz National Wildlife Refuge. Results from this study can be used by resource managers to address identified impairments and protect wildlife habitat and public water supply, and may contribute toward developing more effective water-management plans for Agassiz National Wildlife Refuge.

Minnesota↗

USGS2020

Response of the tallest California building during the Mw7.1 July 5, 2019 Ridgecrest, California earthquake

The 73-story Wilshire Grand in downtown Los Angeles is the recently constructed tallest building in California. It is designed in conformance with performance-based design procedures. The lateral load resisting system of the building is designed with concrete core shear walls, three outriggers with buckling restrained braces (BRBs) located along the height and two three-story truss-belt structural systems. The building is equipped with a 36-channel accelerometric seismic monitoring array that recorded the recent Mw7.1 Ridgecrest earthquake of July 5, 2019, as well as the Mw6.4 July 4, 2019 Ridgecrest Earthquake. In this paper, only the Mw7.1 July 5, 2019 event is studied because of a larger response of the subject building during that earthquake. The earthquake records of July 5, 2019 are specifically studied to determine its dynamic characteristics and building specific behavior. The structure exhibits torsional behavior most likely due to abrupt asymmetrical changes in the thickness and size in-plan of the core shear wall system. Modal shapes, frequencies and critical damping percentages of the building are identified. The translational and torsional modes during the earthquake are not closely coupled with fundamental NS, EW and torsional frequencies (periods) of 0.16 (6.25), 0.27(3.70) and 0.42 (2.38) Hz (seconds). This does not lead to a beating effect even though there is an appearance of it in the displacement records. Due to the relatively low amplitude of shaking during the earthquake, the drift ratios are too small to cause any damage. It is expected that during stronger shaking levels likely to be caused by future events, these characteristics may change and the effect of BRB’s can be better assessed.

California↗

USGS2023

Site occupancy of focal shorebird species at Whiskey Island and Caminada Headland, Louisiana 2012–2020

Coastal restoration through island construction and augmentation is an increasingly common management method in the northern Gulf of Mexico, but evaluating the impacts to shorebird species is difficult. Shorebirds are mostly migratory and many aspects of their life history, including reproduction in some species, occur in other places. In addition, counts or observations of shorebirds made at any given time represent only a portion of the population and that proportion may change with site conditions such as time of day and weather. Dynamic occupancy models can account for imperfect detection and produce estimates of the proportion of area occupied over time as a way to track trends in bird utilization over time. In this chapter we report on occupancy trends for five focal shorebird species from Caminada Headland and Whiskey Island: American Oystercatcher ( Haematopus palliatus ), Piping Plover ( Charadrius melodus ), Red Knot ( Calidris canutus ), Snowy Plover ( Charadrius nivosus ), and Wilson’s Plover ( Charadrius wilsonia ). We examined up to nine years of surveys at the two sites to model long-term trends in occupancy rates from a period spanning before, during, and after restoration. Our objective was to determine if there was change in occupancy over time (trend) during the restoration period. Field sampling was conducted as described in Chapter 1 for the five focal species in this chapter. To create spatial units for occupancy analysis we used a grid of 53 unique cells at Caminada Headland and 26 unique cells at Whiskey Island. All observations of the species were located into spatial units using GIS and presence of each species in each cell was determined for each visit within a sampling season. Sampling seasons were defined for species as the period of time where they were most likely to be using the study area, and corresponded with wintering (August–May), breeding (April–August), or staging (March–October). We did not include covariates for initial occupancy or colonization and site survival because these were small sites with homogenous habitat. We did account for time of year within a season by treating survey date as a covariate of detection probability and allowed it to vary throughout the season. We tested for a trend in occupancy over time by determining if the estimated slope through the series of annual occupancy estimates was significantly different from 0. We conducted 153 total surveys at Caminada Headland from 11 January 2013 to 5 June 2019, and 213 total surveys at Whiskey Island from 7 August 2012 to 19 August 2020. The number of surveys per year varied by species and site and range from 6–23 per species annually at Caminada Headland and 11–28 per species annually at Whiskey Island. Occupancy trends were able to be assessed for all species at both sites, with the exception of the American Oystercatcher, which were only observed in sufficient numbers to estimate occupancy at Whiskey Island. We found a significant positive trend in occupancy from 0.325 to 0.741 for American Oystercatcher at Whiskey Island. There was no significant trend in Piping Plover occupancy at Caminada Headland where occupancy was consistently high (0.910 to 0.947). At Whiskey Island, Piping Plover occupancy estimates increased from 0.574 to 0.908 during the study period which was a significant increase. At Caminada Headland and Whiskey Island Red Knot occupancy varied from 0.482 to 0.891 and 0.350 to 0.742, respectively, but showed no significant trend over the study period. Snowy Plover occupancy at Caminada Headland increased significantly from 0.295 to 0.785 over the study period. Snowy Plover occupancy also increased significantly at Whiskey Island from 0.442 to 0.906. Wilson’s Plover occupancy declined slightly during the study period from 0.946 to 0.935 at Caminada Headland, and from 0.858 to 0.736 at Whiskey Island, but the decline was not significant at either site. We found no evidence that occupancy declined significantly for any of the species during the period prior to, during, and after restoration. We did find a significant increasing trend in occupancy for Snowy Plover at Caminada Headland and a significant increasing trend for American Oystercatcher, Piping Plover, and Snowy Plover at Whiskey Island. Our modeling results indicate that sampling such as this is sufficient for occupancy modeling and can provide a robust metric for comparison over time or among sites. In future research we plan to investigate the sample size needed to detect a trend. We are currently conducting a power analysis to determine the minimum amount of sampling necessary to have power to detect a trend based on the detection probabilities from this study.

Report↗