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At least 505 records · Page 28Linked to original sources
USGS2013

Management of wetlands for wildlife

Wetlands are highly productive ecosystems that provide habitat for a diversity of wildlife species and afford various ecosystem services. Managing wetlands effectively requires an understanding of basic ecosystem processes, animal and plant life history strategies, and principles of wildlife management. Management techniques that are used differ depending on target species, coastal versus interior wetlands, and available infrastructure, resources, and management objectives. Ideally, wetlands are managed as a complex, with many successional stages and hydroperiods represented in close proximity. Managing wetland wildlife typically involves manipulating water levels and vegetation in the wetland, and providing an upland buffer. Commonly, levees and water control structures are used to manipulate wetland hydrology in combination with other management techniques (e.g., disking, burning, herbicide application) to create desired plant and wildlife responses. In the United States, several conservation programs are available to assist landowners in developing wetland management infrastructure on their property. Managing wetlands to increase habitat quality for wildlife is critical, considering this ecosystem is one of the most imperiled in the world.

Book chapter↗
USGS2013

The roles of large top predators in coastal ecosystems: new insights from long term ecological research

During recent human history, human activities such as overhunting and habitat destruction have severely impacted many large top predator populations around the world. Studies from a variety of ecosystems show that loss or diminishment of top predator populations can have serious consequences for population and community dynamics and ecosystem stability. However, there are relatively few studies of the roles of large top predators in coastal ecosystems, so that we do not yet completely understand what could happen to coastal areas if large top predators are extirpated or significantly reduced in number. This lack of knowledge is surprising given that coastal areas around the globe are highly valued and densely populated by humans, and thus coastal large top predator populations frequently come into conflict with coastal human populations. This paper reviews what is known about the ecological roles of large top predators in coastal systems and presents a synthesis of recent work from three coastal eastern US Long Term Ecological Research (LTER) sites where long-term studies reveal what appear to be common themes relating to the roles of large top predators in coastal systems. We discuss three specific themes: (1) large top predators acting as mobile links between disparate habitats, (2) large top predators potentially affecting nutrient and biogeochemical dynamics through localized behaviors, and (3) individual specialization of large top predator behaviors. We also discuss how research within the LTER network has led to enhanced understanding of the ecological roles of coastal large top predators. Highlighting this work is intended to encourage further investigation of the roles of large top predators across diverse coastal aquatic habitats and to better inform researchers and ecosystem managers about the importance of large top predators for coastal ecosystem health and stability.

Florida;Georgia;Massachusetts↗
USGS2015

Southern Salish Sea Habitat Map Series data catalog

In 2010, the U.S. Environmental Protection Agency, Region 10 initiated the Puget Sound Scientific Studies and Technical Investigations Assistance Program, which was designed to support research for implementing the Puget Sound Action Agenda. The Action Agenda was created because Puget Sound was designated as one of 28 estuaries of National Significance under section 320 of the Clean Water Act, and its overall goal is to restore the environment of the Puget Sound Estuary by 2020. The Southern Salish Sea Mapping Project was funded through the Assistance Program request for proposal process which also supports a large number of coastal-zone- and ocean-management issues, and includes the recommendations of the Marine Protected Areas Work Group to the Washington State Legislature. These recommendations include a Puget Sound and coast-wide marine conservation needs assessment, gap analysis of existing Marine Protected Areas and recommendations for action. Four areas with recently acquired National Ocean Service hydrographic data are included in the Southern Salish Sea Habitat Map Series (fig. 1), each to be published individually as USGS Open File Reports at a scale of 1:40,000. The map products display seafloor geoforms, substrate, and biotopes using the Coastal and Marine Ecological Classification Standard. This data catalog contains much of the data used to prepare the SIMs in the Southern Salish Sea Habitat Map Series. Other data that were used to prepare the maps were compiled from previously published sources (for example, sediment samples and seismic reflection profiles) and are not included in this data series.

Washington↗
USGS2025

Assessing decadal-scale coastal change likelihood to define the accuracy and application of scientific information

Defining the accuracy and uncertainties of scientific data products is critical to the usability and trustworthiness of scientific information for environmental management and conservation purposes, such as coastal resource prioritization, design, adaptation, and mitigation. The U.S. Geological Survey has a new decadal-scale coastal change assessment product that synthesizes nearly two dozen coastal datasets. A supervised machine-learning framework is used to combine existing datasets that describe the landscape and the hazards that affect it to determine the coastal change likelihood (CCL) in the coming decade at a resolution of 10 m per pixel for the NE United States from Maine to Virginia. Here, results from a series of statistical tests conducted on source data, the supervised classification, and the CCL outcomes as compared with historical land-cover change are presented. The overall accuracy of the aggregated land-cover dataset that serves as the foundation to which other source datasets are appended is 94%. The supervised learning classification that determines the final CCL output has an overall accuracy of 92%. The CCL predictions of high expected coastal change were consistent with 95% of the coastal and low-elevation landscape change in the last 20 years, as recorded by the Coastal Change Analysis Program land-cover change atlas. Results suggest that CCL provides accurate estimates of coastal landscape change in the next decade that are consistent with recent observed change. Additionally, best practices for applying CCL for planning purposes are outlined, and citing limitations, knowledge gaps, and opportunities for improved accuracy and further investigation are considered.

Journal of Coastal Research↗
USGS2011

Modeling management scenarios and the effects of an introduced apex predator on a coastal riverine fish community

The flathead catfish Pylodictis olivaris, a carnivorous fish species native to most of the central interior basin of North America, has been introduced into at least 13 U.S. states and 1 Canadian province. Concurrent declines in abundance of native fishes have been reported in aquatic systems where flathead catfish have been introduced. To evaluate the potential impact of this invasive species on the native fish community we developed an ecosystem simulation model (including flathead catfish) based on empirical data collected from a North Carolina coastal river. The model results suggest that flathead catfish suppress native fish community biomass by 5-50% through both predatory and competitive interactions. However, our model suggests these reductions could be mitigated through sustained exploitation of flathead catfish by recreational or commercial fishers at rates equivalent to those for native flathead catfish populations (annual exploitation = 6-25%). These findings demonstrate the potential for using directed harvest of an invasive species to assist in restoring native communities. ?? Copyright by the American Fisheries Society 2007.

Transactions of the American Fisheries Society↗
USGS2005

Sediments in marsh ponds of the Gulf Coast Chenier Plain: Effects of structural marsh management and salinity

Physical characteristics of sediments in coastal marsh ponds (flooded zones of marsh associated with little vegetation) have important ecological consequences because they determine compositions of benthic invertebrate communities, which in turn influence compositions of waterbird communities. Sediments in marsh ponds of the Gulf Coast Chenier Plain potentially are affected by (1) structural marsh management (levees, water control structures and impoundments; SMM), and (2) variation in salinity. Based on available literature concerning effects of SMM on sediments in emergent plant zones (zones of marsh occasionally flooded and associated with dense vegetation) of coastal marshes, we predicted that SMM would increase sediment carbon content and sediment hardness, and decrease oxygen penetration (O2 depth) and the silt-clay fraction in marsh pond sediments. Assuming that freshwater marshes are more productive than are saline marshes, we also predicted that sediments of impounded freshwater marsh ponds would contain more carbon than those of impounded oligohaline and mesohaline marsh ponds, whereas C:N ratio, sediment hardness, silt-clay fraction, and O2 depth would be similar among pond types. Accordingly, we measured sediment variables within ponds of impounded and unimpounded marshes on Rockefeller State Wildlife Refuge, near Grand Chenier, Louisiana. To test the above predictions, we compared sediment variables (1) between ponds of impounded (IM) and unimpounded mesohaline marshes (UM), and (2) among ponds of impounded freshwater (IF), oligohaline (IO), and mesohaline (IM) marshes. An a priori multivariate analysis of variance (MANOVA) contrast indicated that sediments differed between IM and UM marsh ponds. As predicted, the silt-clay fraction and O2 depth were lower and carbon content, C:N ratio, and sediment hardness were higher in IM than in UM marsh ponds. An a priori MANOVA contrast also indicated that sediments differed among IF, IO, and IM marsh ponds. As predicted, carbon content was higher in IF marsh ponds than in ponds of other impounded marsh types. In contrast to our predictions, C:N ratio and sediment hardness were lowest and silt-clay fraction and O2 depth were highest in IO and IM marsh ponds. Our results indicated that SMM has affected physical properties of sediments in coastal marsh ponds. Moreover, sediments in IF marsh ponds were affected more so than were those in IO and IM marsh ponds. Our results, in conjunction with those of previous studies, indicated that sediments of marsh ponds and emergent plant zones differed greatly. We predict that changes in pond sediments due to SMM will promote greater epifaunal macroinvertebrate biomass, which in turn should attract larger populations of wintering waterbirds. However, waterbirds that filter or probe soft sediments may be negatively affected by SMM because of the expected decrease in infaunal invertebrate biomass. ?? Springer 2005.

Wetlands Ecology and Management↗
USGS2021

Using uncrewed aerial vehicles for identifying the extent of invasive Phragmites australis in treatment areas enrolled in an adaptive management program

Higher spatial and temporal resolutions of remote sensing data are likely to be useful for ecological monitoring efforts. There are many different treatment approaches for the introduced European genotype of Phragmites australis , and adaptive management principles are being integrated in at least some long-term monitoring efforts. In this paper, we investigated how natural color and a smaller set of near-infrared (NIR) images collected with low-cost uncrewed aerial vehicles (UAVs) could help quantify the aboveground effects of management efforts at 20 sites enrolled in the Phragmites Adaptive Management Framework (PAMF) spanning the coastal Laurentian Great Lakes region. We used object-based image analysis and field ground truth data to classify the Phragmites and other cover types present at each of the sites and calculate the percent cover of Phragmites , including whether it was alive or dead, in the UAV images. The mean overall accuracy for our analysis with natural color data was 91.7% using four standardized classes (Live Phragmites , Dead Phragmites , Other Vegetation, Other Non-vegetation). The Live Phragmites class had a mean user’s accuracy of 90.3% and a mean producer’s accuracy of 90.1%, and the Dead Phragmites class had a mean user’s accuracy of 76.5% and a mean producer’s accuracy of 85.2% (not all classes existed at all sites). These results show that UAV-based imaging and object-based classification can be a useful tool to measure the extent of dead and live Phragmites at a series of sites undergoing management. Overall, these results indicate that UAV sensing appears to be a useful tool for identifying the extent of Phragmites at management sites.

Michigan, Wisconsin↗
USGS2005

Assessment of regional management strategies for controlling seawater intrusion

Simulation-optimization methods, applied with adequate sensitivity tests, can provide useful quantitative guidance for controlling seawater intrusion. This is demonstrated in an application to the West Coast Basin of coastal Los Angeles that considers two management options for improving hydraulic control of seawater intrusion: increased injection into barrier wells and in lieu delivery of surface water to replace current pumpage. For the base-case optimization analysis, assuming constant groundwater demand, in lieu delivery was determined to be most cost effective. Reduced-cost information from the optimization provided guidance for prioritizing locations for in lieu delivery. Model sensitivity to a suite of hydrologic, economic, and policy factors was tested. Raising the imposed average water-level constraint at the hydraulic-control locations resulted in nonlinear increases in cost. Systematic varying of the relative costs of injection and in lieu water yielded a trade-off curve between relative costs and injection/in lieu amounts. Changing the assumed future scenario to one of increasing pumpage in the adjacent Central Basin caused a small increase in the computed costs of seawater intrusion control. Changing the assumed boundary condition representing interaction with an adjacent basin did not affect the optimization results. Reducing the assumed hydraulic conductivity of the main productive aquifer resulted in a large increase in the model-computed cost. Journal of Water Resources Planning and Management ?? ASCE.

Journal of Water Resources Planning and Management↗
USGS2025

Outwash events inhibit vegetation recovery and prolong coastal vulnerability

Overwash, when high ocean water levels and waves flood a coastline, is a common phenomenon that can lead to washover deposits and barrier rollover. Outwash, by contrast, involves seaward flow, often driven by high back-barrier water levels, and can produce washout channels and nearshore deposition. Our observations show that washout channels were quickly (days to weeks) filled and reshaped into beaches, berms, and washover deposits and ponds often formed at the landward ends. However, there was a significant delay in revegetation of former washout areas compared with washover areas. North Core Banks, North Carolina, was affected by repeat hurricanes in different ways: Hurricane Florence (2018) deposited large washover fans 0.5–1 m thick, and Hurricane Dorian (2019) removed 1–4 m of sediment from washout channels. Aerial surveys captured vegetation recolonization on the Florence washover fans within a year but, after Dorian, surveys showed that although the washout channels and ponds quickly filled with marine sand, the channel throats and new washover platforms remained mostly unvegetated for five years. New vegetation growth was associated with the washout ponds and was characteristic of low-elevation hydrophilic environments. We observed comparable outcomes at washout and washover locations on the coasts of Texas and New York and suggest that outwash interrupts the normal cycle of vegetation and dune growth that is key to rebuilding barrier islands after storms. The lack of vegetation in the former washout channels prolongs vulnerability to overwash, further delaying recovery. Our findings have implications for best-management practices and modeling of coastal geomorphic evolution.

JGR Earth Surface↗
USGS2023

Predatory impacts of invasive Blue Catfish in an Atlantic coast estuary

Objective Predatory invasive fishes may consume species of management interest and alter food webs. Blue Catfish Ictalurus furcatus is a large-bodied, salinity-tolerant species that exhibits broad diet breadth and preys on species of both conservation concern and fisheries management interest. To better understand the ecological consequences of the establishment of Blue Catfish fisheries, estimates of predatory impacts are needed. Methods Using a Monte Carlo simulation, we integrated abundance estimates, diet information, and consumption-to-biomass ratios to estimate population-level Blue Catfish predation for a large Chesapeake Bay tributary along the mid-Atlantic coast of the United States, the James River. Result Population-level annual predation estimates by Blue Catfish exceeded 100 metric tons for several species or taxa of interest, including an estimated 400.7 metric tons (95% CI = 272.6–613.2) of blue crab Callinectes sapidus . Prey species abundances were unknown and thus limited opportunities to evaluate prey population responses. For instance, effects of Blue Catfish on blue crab populations remain unknown without tributary-specific estimates of blue crab abundance, but comparisons to landings data suggests that Blue Catfish predation on blue crab in the James River may be low compared with harvest. Conclusion Estimation of Blue Catfish predatory effects may inform development of management goals and objectives that balance diverse stakeholder interests. This work provides beneficial information to assess trade-offs of Blue Catfish fisheries and their effects on coastal aquatic resources.

Virginia↗
USGS2015

Habitat fragmentation in coastal southern California disrupts genetic connectivity in the cactus wren ( Campylorhynchus brunneicapillus )

Achieving long-term persistence of species in urbanized landscapes requires characterizing population genetic structure to understand and manage the effects of anthropogenic disturbance on connectivity. Urbanization over the past century in coastal southern California has caused both precipitous loss of coastal sage scrub habitat and declines in populations of the cactus wren ( Campylorhynchus brunneicapillus ). Using 22 microsatellite loci, we found that remnant cactus wren aggregations in coastal southern California comprised 20 populations based on strict exact tests for population differentiation, and 12 genetic clusters with hierarchical Bayesian clustering analyses. Genetic structure patterns largely mirrored underlying habitat availability, with cluster and population boundaries coinciding with fragmentation caused primarily by urbanization. Using a habitat model we developed, we detected stronger associations between habitat-based distances and genetic distances than Euclidean geographic distance. Within populations, we detected a positive association between available local habitat and allelic richness and a negative association with relatedness. Isolation-by-distance patterns varied over the study area, which we attribute to temporal differences in anthropogenic landscape development. We also found that genetic bottleneck signals were associated with wildfire frequency. These results indicate that habitat fragmentation and alterations have reduced genetic connectivity and diversity of cactus wren populations in coastal southern California. Management efforts focused on improving connectivity among remaining populations may help to ensure population persistence.

California↗
USGS2020

Gear comparison study for sampling nekton in Barataria Basin marshes

This project was funded by the Louisiana Trustee Implementation Group (LA TIG) to support decisions related to investments in long-term monitoring. The LA TIG seeks to ensure long-term monitoring informs coastal restoration activities with the goal of sustaining and improving fisheries impacted by the Deepwater Horizon (DWH) Oil Spill. The project objective was to compare nekton catch across an estuarine gradient using different sampling gear with the goal of identifying trade-offs among nekton sampling approaches. To accomplish this objective, Louisiana Department of Wildlife and Fisheries (LDWF), The Water Institute of the Gulf (the Institute), Dynamic Solutions, LLC, Louisiana State University Agricultural Center (LSU AgCenter), and the U.S. Geological Survey (USGS) completed a field gear comparison study from 2018 to 2019. This work compared electrofisher and seine sampling at 12 fixed stations in Barataria Basin using data collected by LDWF. In addition, and in conjunction with LDWF monthly sampling, the same 12 fixed stations were sampled in May 2019 using a throw trap to compare nekton catch and assemblages collected with the throw trap, seine and electrofisher. LDWF has been conducting seine sampling since 1986, and seine data are used by the State of Louisiana to assess juvenile shrimp, crab and fish abundances, sizes and overall assemblages. In 2018, LDWF began conducting electrofisher sampling at 12 Barataria Basin seine stations in order to determine if the two gear types sample similar species and assemblages for potential future replacement of long-term seine sampling with electrofishing. Throw traps were included as they provide density estimates, which are ultimately the desired statistic used in modeling trophic webs, and are used in assessing habitat restoration outcomes. The project compared the nekton catch and assemblages collected using seine, electrofisher, and throw trap data from marsh edge habitats located across the estuarine gradient in Barataria Basin. Specifically, catch per unit effort (CPUE), species richness, species-specific total length (mm) distribution and nekton assemblages were compared between gear types. The first dataset was collected in May 2019 with throw trap (Appendix A), seine (LDWF data), and electrofisher (LDWF data) gear, and the second dataset (collected by LDWF) spanned 14 months of seine and electrofisher monthly sampling occurring from May 2018 through June 2019 at 12 stations in Barataria Basin. Key findings include that gear bias was not evident across the range of water quality conditions (salinity, temperature, o C, dissolved oxygen, mg L-1 , turbidity, NTU; Appendix B: scatter plots) captured during this pilot study, but differences in nekton catch per unit effort (CPUE) and assemblages were evident between gear types. However, those differences largely depended on the parameter examined. For example, the overall CPUE was highest for electrofishing, followed by seine, and then throw trap. When grass shrimp (the most abundant taxon collected) were removed from CPUE, the electrofisher and seine results were similar in CPUE. When CPUE was corrected for gear efficiency and total area sampled, the throw trap had the highest reported density of nekton sampled, followed by electrofisher and seine results. Electrofishing captured the highest number of species, which included more unique species compared to seine or throw trap catches, though all gear types captured at least one unique species. These highlight a need for caution in interpreting assemblage and density data when comparing datasets derived from different sampling methodologies. These key findings can help inform implementation and interpretation of long-term monitoring data in Louisiana as management decisions are made about coastal restoration projects to sustain and improve fisheries. There are trade-offs in selecting gear types for estuarine nekton monitoring of density, abundance, species richness, and assemblages. The table below (Table 1) summarizes some considerations when selecting gear types for long-term monitoring of estuarine nekton. In addition to biological and ecological considerations, other important considerations include cost, the labor required to conduct sampling, logistics, and potential uncertainties related to how effective each gear type is for sampling the wide variety of conditions found across Louisiana’s coastal habitats. For example, although electrofishing may capture higher CPUE, the equipment is more expensive to obtain and maintain compared to the other gear types. Most importantly, this table highlights differences in the nekton assemblages sampled by each gear type; this consideration is critical when designing the goals of a long-term monitoring program as it will inform how the data can be used and interpreted in the future. This report provides caveats, assumptions, and recommendations that can help support the Louisiana Coastal Protection and Restoration Authority (CPRA), LDWF and the LA TIG in comparing data from different gear types, and in making decisions for future monitoring. Findings from this study are limited to the range of water quality conditions occurring during these data collection events; these data and analyses could benefit from sampling across a wider range of water quality conditions, and collection of habitat structure and bottom type data which are not routinely collected but critically influence nekton. Further investigation examining how relative differences detected in key species abundances between gear types might impact ecosystem indicators and energetics in a modeled food web would provide valuable input to understand outputs of the Comprehensive Aquatic System Model for Barataria Basin, including the potential impacts of nekton monitoring decisions on food web models.

Louisiana↗
USGS2001

Patterns and processes of wetland loss in coastal Louisiana are complex: A reply to Turner 2001. Estimating the indirect effects of hydrologic change on wetland loss: If the Earth is curved, then how would we know it?

The coastal wetlands of Louisiana comprise a vast expanse of marine to freshwater wetland plant communities interspersed w-ith shallow bays and bayous. These wetlands were built by processes associated with the present-day Mississippi and Atchatfalaya River deltas and older distributaries occupied by the river over the past 7,000 }rears. The high rates of wetland loss identified in this system during the 20th century have serious consequences for living resources (Boesch et al. 1994) and coastal residents, and they affect our ability to maintain navigation and flood control. The restoration and management response to this problem must be grounded in a sound understanding of the causative factors. The system has been highly altered by river levees, roads and railway embankments, impoundments, and canals of many dimensions dredged for a variety of purposes. These changes have been imposed on a landscape that is essentially the result of a delicate natural balance between wetland building processes and compaction, subsidence, and sea-level rise. Many now recognize that coastal wetlands can cope with relatively high rates of subsidence and sea-level rise, as long as the processes that ensure wetland sustainability through vertical accumulation of substrate remain unimpaired (Boesch et al. 2000). The challenge facing both the scientific community and coastal resource managers in Louisiana is to look to the future. We must use our understanding of the problem and how it evolved to develop a multi-use ecosystem management plan, and some efforts have been made by state and federal agencies towards this goal (LCWCRTF & WCRA 1998). The present discussions (Turner 1997, 2001; Day et al. 2000; Gosselink 2001) demonstrate the complexity of the issues faced in Louisiana. While such discourse is common in the scientific community where varied approaches and interpretations are a sign of vitality, it is helpful to be clear about the state of knowledge and what levels of uncertainty exist. We seek to clarify some of the issues that have been raised in the discussion, recognizing that our best-available science cannot yet resolve many of them as completely as all would like.

Louisiana↗
USGS2011

The role of surface and subsurface processes in keeping pace with sea level rise in intertidal wetlands of Moreton Bay, Queensland, Australia

Increases in the elevation of the soil surfaces of mangroves and salt marshes are key to the maintenance of these habitats with accelerating sea level rise. Understanding the processes that give rise to increases in soil surface elevation provides science for management of landscapes for sustainable coastal wetlands. Here, we tested whether the soil surface elevation of mangroves and salt marshes in Moreton Bay is keeping up with local rates of sea level rise (2.358 mm y -1 ) and whether accretion on the soil surface was the most important process for keeping up with sea level rise. We found variability in surface elevation gains, with sandy areas in the eastern bay having the highest surface elevation gains in both mangrove and salt marsh (5.9 and 1.9 mm y -1 ) whereas in the muddier western bay rates of surface elevation gain were lower (1.4 and -0.3 mm y -1 in mangrove and salt marsh, respectively). Both sides of the bay had similar rates of surface accretion (~7–9 mm y -1 in the mangrove and 1–3 mm y -1 in the salt marsh), but mangrove soils in the western bay were subsiding at a rate of approximately 8 mm y -1 , possibly due to compaction of organic sediments. Over the study surface elevation increments were sensitive to position in the intertidal zone (higher when lower in the intertidal) and also to variation in mean sea level (higher at high sea level). Although surface accretion was the most important process for keeping up with sea level rise in the eastern bay, subsidence largely negated gains made through surface accretion in the western bay indicating a high vulnerability to sea level rise in these forests.

Queensland↗
USGS2024

Discerning sediment provenance in the Outer Banks (USA) through detrital zircon geochronology

Detrital zircon data from modern barrier island and estuarine environments in the Outer Banks (Atlantic Coast, USA) were statistically compared to sands from nearby rivers to assist in determining source-to-sink pathways. Fluvial samples, collected from near the Fall Line contact between the Appalachian Orogen and sediments of the coastal plain, all have age unique distributions, making them ideal for tracing provenance. Three samples from the Atlantic foreshore showed high similarities to one another, as well as to three samples from the estuarine (back-barrier) Pamlico and Albemarle Sounds. Mixture modeling with multiple data reduction methods and three different statistical tests for similarity consistently indicated that the nearby Potomac River was the primary source for all Atlantic foreshore and estuarine zircons, followed by minor contributions from the James River in some models. The models indicate little or no sediment contribution from the Susquehanna, Roanoke, Tar, Neuse, Cape Fear, and Peedee Rivers. Both Atlantic foreshore and estuarine sands are therefore interpreted to have initially originated from Appalachian bedrock to the north of their present-day location, and subsequently to have been transported southward through the Chesapeake Bay watershed before deposition in Virginia and North Carolina. Prior to barrier island formation in the last several thousand years, differing geomorphology of the Chesapeake Bay facilitated southward movement of sediments from its constituent rivers via longshore drift, where they were deposited in coastal settings on the mainland. The modern barrier islands, formed during the most recent post-glacial transgression, may be reworked from these deposits, but may also include a contribution from sediments that were derived more recently from relict deposits on the shelf. Oceanographic and sedimentological evidence suggests that movement of sand-sized grains from southern rivers across the back-barrier sounds is unlikely. These findings can assist with coastal resilience planning and resource management in a region under severe threat from climate change and rising sea levels.

North Carolina, Virgina↗
USGS2023

Environmental factors influencing detection efficiency of an acoustic telemetry array and consequences for data interpretation

Background Acoustic telemetry is a commonly used technology to monitor animal occupancy and infer movement in aquatic environments. The information that acoustic telemetry provides is vital for spatial planning and management decisions concerning aquatic and coastal environments by characterizing behaviors and habitats such as spawning aggregations, migrations, corridors, and nurseries, among others. However, performance of acoustic telemetry equipment and resulting detection ranges and efficiencies can vary as a function of environmental conditions, leading to potentially biased interpretations of telemetry data. Here, we characterize variation in detection performance using an acoustic telemetry receiver array deployed in Wellfleet Harbor, Massachusetts, USA from 2015 to 2017. The array was designed to study benthic invertebrate movements and provided an in situ opportunity to identify factors driving variation in detection probability. Results The near-shore location proximate to environmental monitoring allowed for a detailed examination of factors influencing detection efficiency in a range-testing experiment. Detection ranges varied from < 50 to 1,500 m and efficiencies varied from 0 to 100% within those detection ranges. Detection efficiency was affected by distance, wind speed and direction, wave height and direction, water temperature, water depth, and water quality. Conclusions Performance of acoustic telemetry systems is strongly contingent on environmental conditions. Our study found that wind, waves, water temperature, water quality, and depth all affected performance to an extent that could seriously compromise a study if these effects were not taken into consideration. Other unmeasured factors may also be important, depending on the characteristics of each site. This information can help guide future telemetry study designs by helping researchers anticipate the density of receivers required to achieve study objectives. Researchers can further refine and document the reliability of their data by incorporating continuously deployed range-testing tags and prior knowledge on varying detection efficiency into movement and occupancy models.

Massachusetts↗
USGS2023

Satellite telemetry reveals space use of diamondback terrapins

Movement and space use information of exploited and imperiled coastal species is critical to management and conservation actions. While satellite telemetry has been successfully used to document movements of marine turtles, the large tag sizes available have limited use on smaller turtle species. We used small Argos-based satellite tags to document movement patterns of diamondback terrapins ( Malaclemys terrapin ), the only estuarine turtle species in North America. Movement data from ten terrapins in St. Joseph Bay, Florida were gathered between July 13, 2018 and July 22, 2021. We estimated seasonal space use using the daily locations generated from a Bayesian hierarchical state-space model to calculate minimum convex polygons (95% MCP) and kernel density estimates (50% and 95% KDE). Mean tracking duration was 125 days and mean home range size was 9.4 km 2 (95% MCP) and 8.1 km 2 (95% KDE). Seagrass habitat comprised 55.8% of all home ranges on average, whereas salt marsh comprised a mean of 3.0%. Mean elevation used by terrapins was − 0.13 m (95% MCP) and -0.35 m (95% KDE). Satellite telemetry provided broad-scale spatiotemporal movement and space use data; however, Argos error produced considerable noise relative to true terrapin movements given their size, speed, and behavior. Terrapin home ranges were greater than previously reported and three of the ten terrapins exhibited repeated long-distance, directed movements within the bay. Small patches of salt marsh habitat were centralized within home ranges, despite comprising only a small percentage for each terrapin. Moreover, the percentage of salt marsh present in each core use area was positively correlated with terrapin mass. Although considered an estuarine species, seagrass habitat comprised a large portion of terrapin home ranges; however, our data did not provide the detail necessary to understand how terrapins were using this habitat. As northward-expanding mangroves continue to infringe upon salt marsh habitat, there is potential for negative impacts to terrapin populations across the northern Gulf of Mexico. As salt marsh habitat continues to be infringed upon by northward-expanding mangroves impacts to terrapins across the northern Gulf of Mexico.

Florida↗
USGS2007

Temporal changes of populations and trophic relationships of wintering diving ducks in Chesapeake Bay

Population and trophic relationships among diving ducks in Chesapeake Bay are diverse and complex as they include five species of bay ducks (Aythya spp.), nine species of seaducks (Tribe Mergini), and the Ruddy Duck (Oxyura jamaicensis). Here we considered the relationships between population changes and diet over the past half century to assess the importance of prey changes to wintering waterfowl in the Bay. Food habits of 643 diving ducks collected from Chesapeake Bay during 1999-2006 were determined by analyses of their gullet (esophagus and proventriculus) and gizzard contents and compared to historical data (1885-1979) of 1,541 diving ducks. Aerial waterfowl surveys, in general, suggest that six species of seaducks were more commonly located in the meso- to polyhaline areas of the Bay, whereas five species of bay ducks and Ruddy Ducks were in the oligo- to mesohaline areas. Seaducks fed on a molluscan diet of Hooked Mussel (Ischadium recurvum), Amethyst Gemclam (Gemma gemma), and Dwarf Surfclarn (Mulinia lateralis). Bay ducks and Ruddy Ducks fed more on Baltic Macoma (Macoma balthica), the adventive Atlantic Rangia (Rangia cuneata), and submerged aquatic vegetation (SAV). Mergansers were found over the widest salinity range in the Bay, probably because of their piscivorous diet. Each diving duck species appears to fill a unique foraging niche, although there is much overlap of selected prey. When current food habits are compared to historic data, only the Canvasback (Aythya valisineria) has had major diet changes, although SAV now accounts for less food volume for all diving duck species, except the Redhead (Aythya americana). Understanding the trophic-habitat relationships of diving ducks in coastal wintering areas will give managers a better understanding of the ecological effects of future environmental changes. Intensive restoration efforts on SAV and oyster beds should greatly benefit diving duck populations.

Waterbirds↗