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At least 775 records · Page 43Linked to original sources
USGS2006

Salt marsh dieback in coastal Louisiana: Survey of plant and soil conditions in Barataria and Terrebonne basins, June 2000-September 2001

Sudden and extensive dieback of the perennial marsh grass, Spartina alterniflora Loisel (smooth cordgrass), which dominates regularly flooded salt marshes along the Gulf of Mexico and Atlantic coastlines, occurred in the coastal zone of Louisiana. The objectives of this study were to assess soil and plant conditions in dieback areas of the Barataria-Terrebonne estuarine system as well as vegetative recovery during and after this dieback event. Multiple dieback sites were examined along 100 km of shoreline from the Atchafalaya River to the Mississippi River during the period from June 2000 through September 2001. The species primarily affected was S. alterniflora; sympatric species such as Avicennia germinans (L.) Stearn (black mangrove) and Juncus roemerianus Scheele (needlegrass rush) showed no visible signs of stress. The pattern of marsh dieback was distinctive with greatest mortality in the marsh interior, suggesting a correlation with local patterns of soil chemistry and/or hydrology. Little or no expansion of dieback occurred subsequent to the initial event, and areas with 50 percent or less mortality in the fall of 2000 had completely recovered by April 2001. Recovery was slower in interior marshes with 90 percent or greater mortality initially. However, regenerating plants in dieback areas showing some recovery were robust, and reproductive output was high, indicating that the causative agent was no longer present and that post-dieback soil conditions were actually promoting plant growth. Stands of other species within or near some dieback sites remained largely unchanged or expanded (A. germinans) into the dead salt marsh. The cause of the dieback is currently unknown. Biotic agents and excessive soil waterlogging/high sulfide were ruled out as primary causes of this acute event, although they could have contributed to overall plant stress and/or interacted with the primary agent to cause plant mortality. Our observations over the 15 month study specifically do not support the contention that dieback was caused by excessive grazing by Littoraria irrorata (marsh periwinkle). Instead, the data show that snails were responding to plant mortality and played an important role in rapid degradation of dead material in some areas. The dieback event was coincident with an extreme drought, low river discharge, and low sea level. These conditions could have caused plant mortality by directly decreasing water availability, increasing salinity, and/or causing oxidation and acidification of soils. The latter scenario was supported by findings of higher pyrite and acid-extractable aluminum and iron, higher acidification potential of dieback soils, and higher concentrations of aluminum and iron in dieback plant tissues (indicating uptake of potentially toxic metals) when compared to reference marshes showing no dieback. The implication of these findings is that periodic weather extremes may play a greater role in shaping coastal plant communities than has previously been recognized. Although such events may not be controlled directly, the resilience and recovery of the system may be altered by management. Such considerations will become increasingly important as global climate changes and human pressures in the coastal zone grow.

Louisiana↗
USGS2014

U.S. response to a report of infectious salmon anemia virus in Western North America

Federal, state, and tribal fishery managers, as well as the general public and their elected representatives in the United States, were concerned when infectious salmon anemia virus (ISAV) was suspected for the first time in free-ranging Pacific Salmon collected from the coastal areas of British Columbia, Canada. This article documents how national and regional fishery managers and fish health specialists of the U.S. worked together and planned and implemented actions in response to the reported finding of ISAV in British Columbia. To date, the reports by Simon Fraser University remain unconfirmed and preliminary results from collaborative U.S. surveillance indicate that there is no evidence of ISAV in U.S. populations of free-ranging or marine-farmed salmonids on the west coast of North America.

Fisheries↗
USGS1999

Microsatellite analyses of Alameda Creek Rainbow/Steelhead trout

Microsatellite genetic diversity found in Alameda Creek rainbow trout support a close genetic relationship with coastal trout found in Lagunitas Creek, Marin County, California. No significant genotypic or allelic frequencies associations could be drawn among Alameda Creek trout and fish collected from the four primary rainbow trout hatchery strains in use in California, Whitney, Mount Shasta, Coleman, and Hot Creek strains, indeed, genetic distance analyses (δμ 2 ) supported genetic separation among Alameda Creek trout and hatchery trout with greater than 50% bootstrap values in 1000 replicate neighbor-joining trees. Fish collected for this study from Palo Seco and Sheppard Creeks shared allelic frequencies with both the fish in Alameda Creek and those found in Scott Creek in Santa Cruz County. Fish collected in Horseshoe Creek or San Lorenzo Creek (Alameda County) did not share this unique genetic relationship between Alameda Creek fish and putative wild coastal trout. These two streams had allelic frequencies similar to some hatchery trout strains and to wild trout captured in the Central Valley. These data suggest that there are two possible steelhead ESUs using the tributaries of San Francisco Bay (one coastal and one Central Valley) or that hatchery trout supplementation has impacted some, but not all streams with a subsequent loss of locally adapted genetic characteristics. These data support the implementation of conservation management of rainbow trout in the Alameda Creek drainage as part of the central California coastal steelhead ESU.

California↗
USGS2015

Human activities and climate variability drive fast-paced change across the world's estuarine-coastal ecosystems

Time series of environmental measurements are essential for detecting, measuring and understanding changes in the Earth system and its biological communities. Observational series have accumulated over the past 2–5 decades from measurements across the world's estuaries, bays, lagoons, inland seas and shelf waters influenced by runoff. We synthesize information contained in these time series to develop a global view of changes occurring in marine systems influenced by connectivity to land. Our review is organized around four themes: (i) human activities as drivers of change; (ii) variability of the climate system as a driver of change; (iii) successes, disappointments and challenges of managing change at the sea-land interface; and (iv) discoveries made from observations over time. Multidecadal time series reveal that many of the world's estuarine–coastal ecosystems are in a continuing state of change, and the pace of change is faster than we could have imagined a decade ago. Some have been transformed into novel ecosystems with habitats, biogeochemistry and biological communities outside the natural range of variability. Change takes many forms including linear and nonlinear trends, abrupt state changes and oscillations. The challenge of managing change is daunting in the coastal zone where diverse human pressures are concentrated and intersect with different responses to climate variability over land and over ocean basins. The pace of change in estuarine–coastal ecosystems will likely accelerate as the human population and economies continue to grow and as global climate change accelerates. Wise stewardship of the resources upon which we depend is critically dependent upon a continuing flow of information from observations to measure, understand and anticipate future changes along the world's coastlines.

Global Change Biology↗
USGS2008

Recovery of Ground-Water Levels From 1988 to 2003 and Analysis of Potential Water-Supply Management Options in Critical Area 1, East-Central New Jersey

Water levels in four confined aquifers in the New Jersey Coastal Plain within Water Supply Critical Area 1 have recovered as a result of reductions in ground-water withdrawals initiated by the State in the late 1980s. The aquifers are the Wenonah-Mount Laurel, the Upper and Middle Potomac-Raritan-Magothy, and Englishtown aquifer system. Because of increased water demand due to increased development in Monmouth, Ocean, and Middlesex Counties, five base and nine alternate management models were designed for the four aquifers to evaluate the effects resulting from potential reallocation of part of the Critical Area 1 reductions in withdrawals. The change in withdrawals and associated water-level changes in the aquifers for 1988-2003 are discussed. Generally, withdrawals decreased 25 to 30 Mgal/d (million gallons per day), and water levels increased 0 to 80 ft (feet). The Regional Aquifer-System Analysis (RASA) ground-water-flow model of the New Jersey Coastal Plain developed by the U.S. Geological Survey was used to simulate ground-water flow and optimize withdrawals using the Ground-Water Management Process (GWM) for MODFLOW. Results of the model were used to evaluate the effects of several possible water-supply management options in order to provide the information to water managers. The optimization method, which provides a means to set constraints that support mandated hydrologic conditions, then determine the maximum withdrawals that meet the constraints, is a more cost-effective approach than simulating a range of withdrawals to determine the effects on the aquifer system. The optimization method is particularly beneficial for a regional-scale study of this kind because of the large number of wells to be evaluated. Before the model was run, a buffer analysis was done to define an area with no additional withdrawals that minimizes changes in simulated streamflow in aquifer outcrop areas and simulated movement of ground water toward the wells from areas of possible high chloride concentrations in the northern and southern parts of the Critical Area. Five base water-supply management models were developed. Each management model has an objective function, decision variables, and constraints. Two of the five management models were test cases: clean slate option and reallocation from the Wenonah-Mount Laurel aquifer and Englishtown aquifer system to small volume wells for potable water use. Nine other models also were developed as part of a trade-off analysis between withdrawal amounts and constraint values. The 14 management models included current (2003) or regularly spaced well locations with variations on the constraints of ground-water head, drawdown, velocity at the 250-mg/L (milligram per liter) isochlor, and withdrawal rate. Results of each management model were evaluated in terms of withdrawals, heads, saltwater intrusion, and source of water by aquifer. Each trade-off curve was defined by using six to nine separate management model runs. Results of the management models designed in this study indicate that a withdrawal reallocation of 5 to 20 Mgal/d within Critical Area 1 would increase the area of heads below -30 ft and the velocity at the 250-mg/L isochlor by up to 4 times that of the simulated 2003 results; the range of values are 0 to 521 square miles and 1 to 20 feet per year, respectively. The increase in area of heads below -30 ft was larger in the Middle Potomac-Raritan-Magothy aquifer than in other aquifers because that area was negligible in 2003. The range of modeled withdrawals is closely tied to management-model design. Interpretation of management model results is provided as well as a discussion of limitations.

Scientific Investigations Report↗
USGS1999

Ten years of studies on Maryland's inner Continental Margin and coastal bays

During the past ten years of the Association of American State Geologists-Mineral Management Service Continental Margins Program, the Maryland Geological Survey investigated the sedimentological, paleontological, stratigraphical and geophysical character of Maryland's inner continental shelf. Based on seismic records and sedimentological analyses completed during the first four years, a late Quaternary stratigraphic model was developed. Five distinct stratigraphic units were identified and described on the Maryland inner shelf. These units represent late Pleistocene interglacial deposits, the oldest of which corresponds to pre-Illinoian (oxygen-isotope stages 7 and/or 9) transgressive shelf sands. Overlying the Q1 unit, the Q2 unit is a 6-meter thick mud sequence of oxygen-isotope stage 5 (128-75 ka) age. Units Q3 and Q4 representing fluvial and leading edge estuarine deposits (oxygen-isotope stages 4, 3 and 2) filled numerous paleochannels that were incised into units Q2 and Q1. Modern trailing-edge transgressive shelf shoals (Unit Q5) discontinuously cap the sequence. The 5th and 6th years studies reported on the economic minerals of surficial and cored sediments. Vibracores collected off the Maryland's shelf during previous studies were analyzed for mineral types and abundances, weight percent of general size fractions, and heavy mineral (HM) content. Mineralogic maturity indices were compiled to correlate the THM and economic heavy minerals (EHM) abundances with position offshore, sediment type, and the indices themselves. For the 7th year, the Maryland Geological Survey re-examined geophysical records and lithological data originally collected by the Army Corps of Engineers to locate and assess beach fill borrow areas for the Ocean City Beach Replenishment Project. Data from 163 vibracores and over 300 kilometers of high-resolution seismic profile records collected off Ocean City, Maryland, supported the stratigraphic model developed by MGS during the first four years of the AASG-MMS program. The Maryland coastal bays became the focus of study during the 8th and 9th years during which seismic records, cores and surficial sediment were collected in Isle of Wight and Assawoman Bays. Shallow pretransgression surface was mapped, relating the existing streams to offshore paleochannels. The tenth year study focused on developing a repository for vibracores collected on Maryland's inner continental shelf.During the past ten years of the Association of American State Geologists-Mineral Management Service Continental Margins Program, the Maryland Geological Survey investigated the sedimentological, paleontological, stratigraphical and geophysical character of Maryland's inner continental shelf. Based on seismic records and sedimentological analysis completed during the first four years, a late quaternary stratigraphic model was developed. Five distinct stratigraphic units were identified and described on the Maryland inner shelf. These units represent late Pleistocene interglacial deposits, the oldest of which corresponds to pre-Illinoian transgressive shelf sands.

Marine Georesources and Geotechnology↗
USGS2001

Coastal sage scrub case study

In ecological applications of large-scale spatial data to management decisions concerning land planning and conservation, errors and biases may creep into the analysis and decision making at several steps (see Chaps. 1, 2, and 3), including: • Uncertainty in positions of spatial locations of relevant ecological and physiographic features of the landscape. • Uncertainty of the type and attributes of land cover at a particular location. • Uncertainty in how different land covers at a position in space and the geometric arrangement of land covers nearby might influence an animal species occurrence or distribution, or the magnitude of some ecological process. • Uncertainty about the relative importance of each spatial location to the overall success or persistence of a population or ecological process. • Uncertainty about how to weight each species or ecological process in determining the overall biodiversity and functioning of ecosystems, local and national resource priorities, and consistency with legislative mandates. We would like to be able to quantify the errors at each step, identify biases, and pass these along to the next analysis step so that our degree of uncertainty regarding potential outcomes is evident at each level (e.g., Stoms et al. 1992).

Book chapter↗
USGS2017

A foundation for future assessment and management of groundwater resources

Sequence stratigraphic models for the Pleistocene to Holocene sediments of the Los Angeles (LA) Basin will provide better understanding of regional groundwater flow and have helped identify seawater intrusion pathways into important groundwater aquifers. Because groundwater provides more than one-third of the municipal water supply for the coastal LA Basin, the aquifer architecture of this system is a high priority for groundwater managers. Seismic and sequence stratigraphy are now incorporated into groundwater resource assessments and environmental investigations. By evaluating subsurface data using sequence stratigraphy, the geometry and distribution of aquifer and aquitard sediments are defined, thus groundwater contaminant plumes and sea water intrusion pathways are better understood. The U. S. Geological Survey (USGS), in cooperation with Los Angeles County Department of Public Works and the Water Replenishment District of Southern California undertook an investigation of the groundwater stratigraphy of the Wilmington – Long Beach area of the LA Basin. Sequence stratigraphic methods were used to integrate preexisting groundwater well data with: (1) new borehole observations, (2) structural and physical properties data derived from geophysical measurements, (3) hi-resolution seismic reflection data obtained offshore of the present shoreline, and (4) vintage oil company exploration seismic reflection data from both onshore and offshore of the shoreline. These data were used to construct a series of Pleistocene to Holocene environment of deposition maps that show the overall progradation of sequences seaward over time. In addition, seawater intrusion pathways into coastal groundwater aquifers were identified and mapped. On a more regional scale, a vintage Texaco seismic reflection data set from the greater LA Basin was interpreted and integrated with a regional network of multi-level ground-water monitoring wells. The sequence stratigraphic correlation shows that many of the defined groundwater aquifers are not correlative. For example, one of the major groundwater supply aquifers, the Silverado Aquifer, when tied to the seismic reflection data has different ages depending on location. This new understanding demonstrates the need for a re-evaluation of the Pleistocene to Holocene stratigraphy using existing seismic reflection data integrated with well data from the LA Basin in order to understand the regional distribution of groundwater aquifers.

Conference Paper↗
USGS2021

Historic population estimates for bottlenose dolphins (Tursiops truncatus) in Aragua, Venezuela indicate monitoring need

This study reports historic capture-mark-recapture survival and abundance estimates of common bottlenose dolphins ( Tursiops truncatus ) based on photo-identification surveys of coastal Venezuela (along the Aragua coast between Turiamo Bay and Puerto Colombia). We used the most recent data available: dolphins identified by unique dorsal fin marks during wet and dry season surveys conducted from 2004 to 2008. Dolphin encounter histories were analyzed in the Closed Capture Robust Design framework, with the top model including random movement, constant survival, and capture-recapture probabilities that varied by secondary periods. Survival of marked adults was estimated at 0.99 (95% CI = 0.97 to 1.00). Population estimates for all adults (marked and unmarked) averaged 31 animals (SD = 13.8), and for all dolphins (all adults and calves), 41 animals (SD = 17.2). Coastal bottlenose dolphins face numerous threats, including ship strikes, oil spills, conflict with recreational and industrial fisheries, other negative human interactions, biotoxins, chemicals, noise, freshwater discharge, and coastal development. Further, small populations are, in general, at increased risk due to reduced resiliency and recovery potential when exposed to such threats and to expected environmental and demographic stochasticity. These historic estimates of abundance and survival are critical for establishing a reference state and indicate a need for ongoing monitoring of the small dolphin population while the Aragua coast is still, as of yet, relatively little impacted by humans. Should coastal development increase (as is the global trend) and/or environmental catastrophes (e.g., harmful algal blooms, hurricanes, and oil spills) occur, these historic estimates will be essential for assessing impacts and guiding management and conservation interventions. Our results show year-round dolphin presence and highlight the Venezuelan coastal–oceanic landscape as an area of both future research and conservation importance.

Aragua↗
USGS2013

Benthic substrate classification map: Gulf Islands National Seashore

The 2005 hurricane season was devastating for the Mississippi Gulf Coast. Hurricane Katrina caused significant degradation of the barrier islands that compose the Gulf Islands National Seashore (GUIS). Because of the ability of coastal barrier islands to help mitigate hurricane damage to the mainland, restoring these habitats prior to the onset of future storms will help protect the islands themselves and the surrounding habitats. During Hurricane Katrina, coastal barrier islands reduced storm surge by approximately 10 percent and moderated wave heights (Wamsley and others, 2009). Islands protected the mainland by preventing ocean waves from maintaining their size as they approached the mainland. In addition to storm protection, it is advantageous to restore these islands to preserve the cultural heritage present there (for example, Fort Massachusetts) and because of the influence that these islands have on marine ecology. For example, these islands help maintain a salinity regime favorable to oysters in the Mississippi Sound and provide critical habitats for many migratory birds and endangered species such as sea turtles (Chelonia mydas, Caretta caretta, and Dermochelys coriacea), Gulf sturgeon (Acipenser oxyrinchus desotoi), and piping plovers (Charadrius melodus) (U.S. Army Corps of Engineers, 2009a). As land manager for the GUIS, the National Park Service (NPS) has been working with the State of Mississippi and the Mobile District of the U.S. Army Corps of Engineers to provide a set of recommendations to the Mississippi Coastal Improvements Program (MsCIP) that will guide restoration planning. The final set of recommendations includes directly renourishing both West Ship Island (to protect Fort Massachusetts) and East Ship Island (to restore the French Warehouse archaeological site); filling Camille Cut to recreate a continuous Ship Island; and restoring natural regional sediment transport processes by placing sand in the littoral zone just east of Petit Bois Island. Prevailing sediment transport processes will provide natural renourishment of the westward islands in the barrier system (U.S. Army Corps of Engineers, 2009b). One difficulty in developing the final recommendations is that few data are available to incorporate into restoration plans related to bathymetry, sediment type, and biota. For example, the most recent bathymetry available dates to when East and West Ship Islands were a single continuous island (1917). As a result, the MsCIP program has encouraged post-hurricane bathymetric data collection for future reference. Furthermore, managing a complex environment such as this barrier island system for habitat conservation and best resource usage requires significant knowledge about those habitats and resources. To effectively address these issues, a complete and comprehensive understanding of the type, geographic extent, and condition of marine resources included within the GUIS is required. However, the data related to the GUIS marine resources are limited either spatially or temporally. Specifically, there is limited knowledge and information about the distribution of benthic habitats and the characteristics of the offshore region of the GUIS, even though these are the habitats that will be most affected by habitat restoration. The goal of this project is to develop a comprehensive map of the benthic marine habitats within the GUIS to give park managers the ability to develop strategies for coastal and ocean-resource management and to aid decisionmakers in evaluating conservation priorities.

Mississippi↗
USGS2011

Benthic habitat classification in Lignumvitae Key Basin, Florida Bay, using the U.S. Geological Survey Along-Track Reef Imaging System (ATRIS)

The Comprehensive Everglades Restoration Plan (CERP) funded in partnership between the U.S. Army Corps of Engineers, South Florida Water Management District, and other Federal, local and Tribal members has in its mandate a guideline to protect and restore freshwater flows to coastal environments to pre-1940s conditions (CERP, 1999). Historic salinity data are sparse for Florida Bay, so it is difficult for water managers to decide what the correct quantity, quality, timing, and distribution of freshwater are to maintain a healthy and productive estuarine ecosystem. Proxy records of seasurface temperature (SST) and salinity have proven useful in south Florida. Trace-element chemistry on foraminifera and molluscan shells preserved in shallow-water sediments has provided some information on historical salinity and temperature variability in coastal settings, but little information is available for areas within the main part of Florida Bay (Brewster-Wingard and others, 1996). Geochemistry of coral skeletons can be used to develop subannually resolved proxy records for SST and salinity. Previous studies suggest corals, specifically Solenastrea bournoni, present in the lower section of Florida Bay near Lignumvitae Key, may be suitable for developing records of SST and salinity for the past century, but the distribution and species composition of the bay coral community have not been well documented (Hudson and others, 1989; Swart and others, 1999). Oddly, S. bournoni thrives in the study area because it can grow on a sandy substratum and can tolerate highly turbid water. Solenastrea bournoni coral heads in this area should be ideally located to provide a record (~100-150 years) of past temperature and salinity variations in Florida Bay. The goal of this study was to utilize the U.S. Geological Survey's (USGS) Along-Track Reef Imaging System (ATRIS) capability to further our understanding of the abundance, distribution, and size of corals in the Lignumvitae Key Basin. The study area was subdivided into four areas whereby corals and other benthic habitats were classified based on ATRIS imagery.

Florida↗
USGS2021

Climate change vulnerability assessment for the California coastal national monument—Trinidad and Point Arena-Stornetta units

Executive Summary The California Coastal National Monument protects islets, reefs, and rock outcropping habitats in six onshore units, including the Trinidad and Point Arena-Stornetta Units. The California Coastal National Monument provides crucial habitat for resident and migratory species of seabirds, marine mammals, and invertebrates, which includes several federally listed threatened and endangered species. Also, the California Coastal National Monument encompasses important tribal, cultural, and historical sites along the coastline of California. We used three approaches to assess the climate change vulnerability of the Trinidad and Point Arena-Stornetta Units: (1) a qualitative approach using peer-reviewed literature and previous work done in the Climate Change Vulnerability Assessment for the North-central California Coast and Ocean (Hutto and others, 2015), (2) interactive workshops with local stakeholders to identify specific resources, and (3) spatial analysis to estimate sea-level rise vulnerability for the rocky shoreline and key resources within the units. Information from stakeholder workshops held (in 2017) in the cities of Point Arena and Trinidad identified climate change impacts as an important management concern for the resilience, health, and ecosystem services of the California Coastal National Monument units. Impacts that were identified included sea-level rise, changes in precipitation and fog, warming oceans, and loss of species (birds, fisheries, marine mammals). Boat surveys were done for each unit to estimate the number of rocky features and the biota using the rocks. At the Trinidad Unit, 138 rocks were surveyed and 17 different wildlife species were observed, whereas at the Point Arena-Stornetta Unit, 40 rocks were surveyed and 10 different wildlife species were observed. Individual rocky features surveyed within the units were then ranked on sea-level rise exposure and vulnerability scales with 1 being the least vulnerable/exposed and 5 the most. Forty-nine and fifty-eight percent of surveyed rocks had a sea-level rise exposure ranking of 4 or 5 (high) for the Trinidad Unit and Point Arena-Stornetta Units respectively. Forty-eight percent of offshore rocks had a sea-level rise vulnerability score of 3 or greater (high) for the Trinidad Unit, and forty-three percent of rocks had a vulnerability score of 3 or greater for the Point Arena-Stornetta Unit. When examining guild use of vulnerable rocks (vulnerability score greater than 3), at the Trinidad Unit alcid species (here defined as common murres and pigeon guillemots) were observed on only 28 percent of vulnerable rocks, shorebirds on 30 percent, sea lions on 40 percent, gulls on 43 percent, seabirds on 58 percent, and mammals on 75 percent, whereas at the Point Arena-Stornetta Unit alcid species were observed on 0 percent of vulnerable rocks, gulls on 33 percent, seabirds on 57 percent, and mammals on 50 percent. Sea-level rise has the potential to submerge small low-relief offshore rocks and make them uninhabitable for birds and marine mammals but could provide more intertidal and subtidal rocky habitats. We found that nearly half of the offshore rocks at both sites are vulnerable and have the potential to realize this outcome; however, the larger and tall-relief rocks at these sites are less vulnerable to sea-level rise and are expected to continue to provide habitat for avian species.

California↗
USGS2011

Characterization of geomorphic units in the alluvial valleys and channels of Gulf Coastal Plain rivers in Texas, with examples from the Brazos, Sabine, and Trinity Rivers, 2010

The U.S. Geological Survey, in cooperation with the Texas Water Development Board, described and characterized examples of geomorphic units within the channels and alluvial valleys of Texas Gulf Coastal Plain rivers using a geomorphic unit classification scale that differentiates geomorphic units on the basis of their location either outside or inside the river channel. The geomorphic properties of a river system determine the distribution and type of potential habitat both within and adjacent to the channel. This report characterizes the geomorphic units contained in the river channels and alluvial valleys of Texas Gulf Coastal Plain rivers in the context of the River Styles framework. This report is intended to help Texas Instream Flow Program practitioners, river managers, ecologists and biologists, and others interested in the geomorphology and the physical processes of the rivers of the Texas Gulf Coastal Plain (1) gain insights into how geomorphic units develop and adjust spatially and temporally, and (2) be able to recognize common geomorphic units from the examples cataloged in this report. Recent aerial imagery (high-resolution digital orthoimagery) collected in 2008 and 2009 were inspected by using geographic information system software to identify representative examples of the types of geomorphic units that occurred in the study area. Geomorphic units outside the channels of Texas Gulf Coastal Plain rivers are called \"valley geomorphic units\" in this report. Valley geomorphic units for the Texas Gulf Coastal Plain rivers described in this report are terraces, flood plains, crevasses and crevasse splays, flood-plain depressions, tie channels, tributaries, paleochannels, anabranches, distributaries, natural levees, neck cutoffs, oxbow lakes, and constructed channels. Channel geomorphic units occur in the river channel and are subject to frequent stresses associated with flowing water and sediment transport; they adjust (change) relatively quickly in response to short-term variations in flow. Channel geomorphic units described in this report are channel banks, benches and ledges, bank failures, point bars, cross-bar channels, channel bars, exposed bedrock, pools, runs, and crossovers.

Texas↗
USGS2014

Comprehensive framework for ecological assessment of the Migratory Bird Habitat Initiative following the Deepwater Horizon oil spill

Following the Deepwater Horizon oil spill in the Gulf of Mexico in April 2010, the USDA Natural Resources Conservation Service (NRCS) established and funded the Migratory Bird Habitat Initiative (MBHI), with the goal of improving and increasing wetland habitats on private lands to benefit wintering and migrating waterbirds displaced from oil-impacted coastal wetlands. The NRCS and conservation partners provided financial and technical assistance to landowners and managers of sites enrolled in various conservation easement programs, and incorporated approximately 190,000 ha of wetlands and agricultural lands in the Mississippi Alluvial Valley (MAV) and Gulf Coast regions in the MBHI. In fall 2010, the NRCS worked with scientists and graduate students from three universities and various conservation agencies to design and implement landscape-scale evaluations of (1) the use of MBHI-managed wetlands and comparable non-MBHI wetlands by Charadriiformes (shorebirds), Anseriformes (waterfowl), and other waterbirds; and (2) the relative effectiveness of different MBHI practices for providing habitat and food resources for migrating, resident, and wintering waterbirds. In this paper, we describe the scientific framework designed to evaluate the MBHI in improving waterbird habitats on private lands in the MAV, the Gulf Coast Prairies in Louisiana and Texas, and Gulf coastal wetlands of Mississippi and Alabama. The results of our evaluation will enhance our understanding of the influence of MBHI, other Farm Bill Conservation Initiative managed lands (e.g., Wetland Reserve Program), and selected agricultural working lands (e.g., Oryza sativa L. [Rice] fields in southern Louisiana and Texas) on wintering and migrating waterbirds. A proactive approach that uses science to evaluate governmental conservation programs is relevant and can inform development of meaningful public policy that likely will be needed for effective delivery of future conservation programs and to justify financial incentives paid to landowners to apply best management practices.

Southeastern Naturalist↗
USGS2025

Satellite tracking reveals heavy use of local MPAs by green turtles (Chelonia mydas) nesting in southeast Florida, USA

Florida hosts a regionally important nesting aggregation of green turtles ( Chelonia mydas ) in the North Atlantic, yet internesting and post-nesting movements for this rookery remain poorly understood. Here, we used satellite telemetry to track 23 green turtles nesting on southeast Florida beaches from 2017 to 2021 to investigate their spatial ecology and use of marine protected areas (MPAs) during internesting, migration, and foraging. Marine protected areas are widely used in marine conservation and can be powerful tools for managing species and protecting biodiversity. During internesting, turtles used nearshore, unprotected coastal waters adjacent to the study site. After the nesting season, turtles migrated 24.1 to 203.5 km to previously identified foraging grounds, including areas within Biscayne National Park and Florida Keys National Marine Sanctuary, as well as a high-use but unprotected area off Cape Sable, Florida. Throughout the internesting and foraging periods, turtles exhibited little spatial overlap of core-use areas, suggesting limited space-use sharing even in high-density regions. This study provides the first satellite telemetry dataset for green turtles from southeast Florida and reveals their strong reliance on a relatively small MPA network along southwest Florida. Our findings underscore how these MPAs can support conservation efforts for Florida’s overall green turtle nesting population, while further emphasizing the potential benefits of expanded protections in key areas to safeguard regionally important green turtle habitat.

Florida↗
USGS1995

The value and vulnerability of small estuarine islands for conserving metapopulations of breeding waterbirds

Compelling arguments for preserving large habitat ‘islands’ have been made for a number of animal groups, but most commonly for terrestrial birds. We argue that, for many species of waterbirds nesting in coastal estuaries, maintaining numerous small islands may be a more effective management strategy than maintaining larger islands or reserves. In this study, the number of great white heron Ardea herodias nests over a 5-year period (1986–91) was negatively correlated with island area in the Florida Keys, USA. Nest densities were highest in the 2–10 ha island size range and lowest for islands larger than 100 ha. These small islands also attract nesting black skimmers Rynchops niger , brown pelicans Pelecanus occidentalis , and several species of terns and gulls. Small estuarine islands are vulnerable to sea level rise, erosion from watercraft, and, for dredge material islands, lack of sufficient maintenance because of competing needs for beach nourishment. Managers need to enforce more buffering and protection of these islands and argue for more dredged material allocations in some areas.

Florida↗
USGS2020

Migratory status determines resource selection by American Woodcock at an important fall stopover, Cape May, New Jersey

Migration is a period of high activity and exposure during which risks and energetic demand on individuals may be greater than during nonmigratory periods. Stopover locations can help mitigate these threats by providing supplemental energy en route to the animal’s end destination. Effective conservation of migratory species therefore requires an understanding of use of space that provides resources to migratory animals at stopover sites. We conducted a radio-telemetry study of a short-distance migrant, the American Woodcock ( Scolopax minor ), at an important stopover site, the Cape May Peninsula, New Jersey. Our objectives were to describe land-cover types used by American Woodcock and evaluate home range habitat selection for individuals that stopover during fall migration and those that choose to overwinter. We radio-marked 271 individuals and collected 1,949 locations from these birds (0–21 points individual –1 ) over 4 yr (2010 to 2013) to inform resource selection functions of land-cover types and other landscape characteristics by this species. We evaluated these relationships at multiple spatial extents for (1) birds known to have ultimately left the peninsula (presumed migrants), and (2) birds known to have remained on the peninsula into the winter (presumed winter residents). We found that migrants selected deciduous wetland forest, agriculture, mixed shrub, coniferous wetland forest, and coniferous shrub, while wintering residents selected deciduous wetland forest, coniferous shrub, and deciduous shrub. We used these results to develop predictive models of potential habitat: 7.80% of the peninsula was predicted to be potential stopover habitat for American Woodcock (95% classification accuracy) and 4.96% of the peninsula was predicted to be potential wintering habitat (85% classification accuracy). Our study is the first to report habitat relationships for migratory American Woodcock in the coastal U.S. and provides important spatial tools for local and regional managers to support migratory and winter resident woodcock populations into the future.

New Jersey↗
USGS2015

Estimating regional landbird populations from enhanced North American Breeding Bird Surveys

Estimating the size of bird populations is central to effective conservation planning and prudent management. I updated estimated regional bird populations for the East Gulf Coastal Plain of Mississippi using data from 275 North American Breeding Bird Surveys from 2009 to 2013. However, regional bird populations estimated from count surveys of breeding birds may be biased due to lack of empirical knowledge of the distance at which a species is effectively detected and the probability of detecting a species if it is present. I used data recorded within two distance classes (0–50 m and >50–400 m) and three 1-min time intervals on 130 Breeding Bird Surveys to estimate detection probability and effective detection distance for 77 species. Incorporating these empirical estimates of detection probability and detection distance resulted in estimated regional populations for these species that were markedly greater than regional populations estimated without species-specific estimates of detection parameters. Using the same Breeding Bird Survey data, I also estimated probability of site occupancy for 66 species and extrapolated this to the proportion of area occupied in the East Gulf Coastal Plain of Mississippi. I combined the area occupied with the reported range of breeding territory size for 54 species to obtain independent estimates of regional bird populations. Although the true population of these species is unknown, estimated populations that incorporated empirical estimates of detection probability and detection distance were more likely to be within the range of independently estimated, occupancy-based, regional population estimates than were population estimates that lacked empirical detection and distance information.

Mississippi↗