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At least 721 records · Page 40Linked to original sources

USGS1966

Insecticide contaminations in wetland habitats and their effects on fish- eating birds

An unusual mortality of fish-eating birds occurred at the Tule Lake National Wildlife Refuge in California between 1960 and 1962. Over 1100 dead birds of ten species were found during that period. Investigations of the mortality indicated that birds died as a result of their exposure to toxaphene, which was applied to adjoining agricultural areas, transported to the refuge in waste irrigation water, and accumulated in fish eaten by the birds. Toxaphene was used in agriculture for only 3 years, 1958-60, and by 1962 residues were no longer found in the marsh habitat. However, results also showed that a potentially hazardous contamination of DDT and its metabolites was present in the birds and the environment. Studies were, therefore, continued to determine the food-chain relationships of DDT in marsh ecosystems, and the effects of the insecticide on birds. Sampling for insecticide residues was undertaken at four waterfowl refuges, each representing a somewhat different set of environmental conditions. DDT residues in water at each refuge were found to be relatively low, but filtered samples showed that residues in suspended material were 10 000 to 20 000 times as great as those in the filtrate. Much of the suspended material was organic matter, which is an important source of energy for the ecosystems. In environments with invertebrates, DDT residues were relatively low in sediments and high in fish, while residues in vegetation were highest where invertebrates were absent. Results suggest that organic materials and invertebrates can be important factors in determining the fate and involvement of insecticides in aquatic environments. Studies of the movements, exposure to pesticides, productivity, and longevity of individuals in three nesting colonies of White Pelicans were begun in 1962 to depict the relationships of pesticides to a migratory population of birds dependent upon wetland habitats. To date there is no evidence that the exposure of pelicans to DDT is influencing the population dynamics of the birds.

California, Oregon↗

USGS2006

Interpolation of reconnaissance multibeam bathymetry from north-central Long Island Sound

Introduction The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA) and the Connecticut Department of Environmental Protection (CT DEP), has produced detailed maps of the sea floor in Long Island Sound, a major East Coast estuary surrounded by the most densely populated region of the United States (fig. 1). The current phase of this cooperative research program is directed toward studies of sea-floor topography and its effect on the distributions of sedimentary environments and benthic communities. Because anthropogenic wastes, toxic chemicals, and changes in land-use patterns resulting from residential, commercial, and recreational development have stressed the environment of the Sound, causing degradation and potential loss of benthic habitats (Koppelman and others, 1976; Long Island Sound Study, 1994), detailed maps of the sea floor are needed to help evaluate the extent of adverse impacts and to help manage resources wisely in the future.

Connecticut, New York↗

USGS1972

Reconnaissance engineering geology of the Haines area, Alaska, with emphasis on evaluation of earthquake and other geologic hazards

The Alaska earthquake of March 27, 1964, brought into sharp focus the need for engineering geologic studies in urban areas. Study of the Haines area constitutes an integral part of an overall program to evaluate earthquake and other geologic hazards in most of the larger Alaska coastal communities. The evaluations of geologic hazards that follow, although based only upon reconnaissance studies and, therefore, subject to revision, will provide broad guidelines useful in city and land-use planning. It is hoped that the knowledge gained will result in new facilities being built in the best possible geologic environments and being designed so as to minimize future loss of life and property damage. Haines, which is in the northern part of southeastern Alaska approximately 75 miles northwest of Juneau, had a population, of about 700 people in 1970. It is built at the northern end of the Chilkat Peninsula and lies within the Coast Mountains of the Pacific Mountain system. The climate is predominantly marine and is characterized by mild winters and cool summers. The mapped area described in this report comprises about 17 square miles of land; deep fiords constitute most of the remaining mapped area that is evaluated in this study. The Haines area was covered by glacier ice at least once and probably several times during the Pleistocene Epoch. The presence of emergent marine deposits, several hundred feet above sea level, demonstrates that the land has been uplifted relative to sea level since the last major deglaciation of the region about 10,000 years ago. The rate of relative uplift of the land at Haines during the past 39 years is 2.26 cm per year. Most or all of this uplift appears to be due to rebound as a result of deglaciation. Both bedrock and surficial deposits are present in the area. Metamorphic and igneous rocks constitute the exposed bedrock. The metamorphic rocks consist of metabasalt of Mesozoic age and pyroxenite of probable early middle Cretaceous age. The igneous rocks consist of diorite and quartz diorite (tonalite) of Cretaceous age. Sedimentary rocks of Tertiary age may be present in the mapped area but are not exposed. The surficial deposits of Quaternary age,-have been divided into the following map units on the basis of time Of deposition, mode of origin, and grain size: (1) undifferentiated drift deposits, (2) outwash and Ice-contact deposits; (3) elevated fine-grained marine deposits, (4) elevated shore and delta deposits, (5) alluvial fan deposits, (6) colluvial deposits, (7) modern beach deposits, (8) Chilkat River flood-plain and delta deposits, and (9) manmade fill. Offshore deposits are described but are not mapped. Southeastern Alaska lies within the tectonically active belt that rims the northern Pacific Basin and has been active since at least early Paleozoic time. The outcrop pattern is the result of late Mesozoic and Tertiary deformational, metamorphic, and intrusive events. Large-scale faulting has been common. The two most prominent inferred fault systems in southeastern Alaska and surrounding regions are: (1) The Denali fault system and (2) the Fairweather-Queen Charlotte Islands fault system. In the general area of Haines, rocks of Mesozoic age northeast of Chilkat River have a simple monoclinal structure. Paleozoic-Mesozoic rocks southwest of Chilkat River are gently to rather complexly folded. Several major and numerous minor faults probably transect the general area of Haines but their exact location and character can only be inferred because their traces are coincident to the long axes of fiords and river valleys, where they are concealed by water or by valley-floor deposits. Inferred faults in or near the Haines mapped area are: (1) Chilkat River fault, (2) Chilkoot fault, (3) Takhin fault, and (4) faults in the saddle area at Haines. Southeastern Alaska lies in one of the two most seismically active zones in Alaska, a State where 6 percent of the world's shallow earthqua

Open-File Report↗

USGS2015

Chemical and biotic characteristics of prairie lakes and large wetlands in south-central North Dakota—Effects of a changing climate

The climate of the prairie pothole region of North America is known for variability that results in significant interannual changes in water depths and volumes of prairie lakes and wetlands; however, beginning in July 1993, the climate of the region shifted to an extended period of increased precipitation that has likely been unequaled in the preceding 500 years. Associated changing water volumes also affect water chemical characteristics, with potential effects on fish and wildlife populations. To explore the effect of changing climate patterns, in 2012 and 2013, the U.S. Geological Survey revisited 167 of 178 prairie lakes and large wetlands of south-central North Dakota that were originally sampled in the mid-1960s to mid-1970s. During the earlier sampling period, these lakes and wetlands displayed a great range of chemical characteristics (for example, specific conductance ranged from 365 microsiemens per centimeter at 25 degrees Celsius to 70,300 microsiemens per centimeter at 25 degrees Celsius); however, increased water volumes have resulted in greatly reduced variation among lakes and wetlands and a more homogeneous set of chemical conditions defined by pH, specific conductance, and concentrations of major cations and anions. High concentrations of dissolved solids previously limited fish occurrence in many of the lakes and wetlands sampled; however, freshening of these lakes and large wetlands has allowed fish to populate and flourish where they were previously absent. Conversely, the freshening of previously saline lakes and wetlands has resulted in concurrent shifts away from invertebrate species adapted to live in these highly saline environments. A shift in the regional climate has changed a highly diverse landscape of wetlands (fresh to highly saline) to a markedly more homogeneous landscape that has reshaped the fish and wildlife communities of this ecologically and economically important region.

North Dakota↗

USGS2006

The diamondback terrapin: The biology, ecology, cultural history, and conservation status of an obligate estuarine turtle

Ranging from Cape Cod to nearly the Texas-Mexico border, the diamondback terrapin (Malaclemys terrapin) is the only species of North American turtle restricted to estuarine systems. Despite this extensive distribution, its zone of occurrence is very linear, and in places fragmented, resulting in a relatively small total area of occupancy. On a global scale, excluding marine species, few turtles even venture into brackish water on a regular basis, and only two Asian species approach the North American terrapin's dependency on estuarine habitats. Here we describe some of the biological and behavioral adaptations of terrapins that allow them to live in the rather harsh estuarine environment. In this chapter we review the natural and cultural history of this turtle, discuss conservation issues, and provide information on the types of research needed to make sound management decisions for terrapin populations in peril.

Studies in Avian Biology↗

USGS2003

Lake Clark sockeye salmon population assessment

Radio telemetry was used to identify and map sockeye salmon spawning habitats in glacially influenced Lake Clark, Kvichak River watershed, Alaska. Two hundred eighty-two adult sockeye salmon were radio tagged and tracked to spawning grounds. Thirty-five spawning areas were identified, including 18 previously unidentified. Comparison of radio telemetry data with past aerial population surveys indicate sockeye salmon spawning habitat use and distribution in Lake Clark was underestimated, likely due to poor visibility associated with glacial habitats. Although glacially turbid waters are not considered suitable incubation environments because fine sediments can suffocate embryos, more than 60% of radio tagged fish spawned in such waters. Over 50% of identified spawning areas are along the shores of Lake Clark and Little Lake Clark and about 75% of spawning areas are adjacent to private land. Proposed development on these lands could negatively impact critical spawning habitats if protective measures are not in place.

Report↗

USGS2011

Timing of seasonal migration in mule deer: effects of climate, plant phenology, and life-history characteristics

Phenological events of plants and animals are sensitive to climatic processes. Migration is a life-history event exhibited by most large herbivores living in seasonal environments, and is thought to occur in response to dynamics of forage and weather. Decisions regarding when to migrate, however, may be affected by differences in life-history characteristics of individuals. Long-term and intensive study of a population of mule deer ( Odocoileus hemionus ) in the Sierra Nevada, California, USA, allowed us to document patterns of migration during 11 years that encompassed a wide array of environmental conditions. We used two new techniques to properly account for interval-censored data and disentangle effects of broad-scale climate, local weather patterns, and plant phenology on seasonal patterns of migration, while incorporating effects of individual life-history characteristics. Timing of autumn migration varied substantially among individual deer, but was associated with the severity of winter weather, and in particular, snow depth and cold temperatures. Migratory responses to winter weather, however, were affected by age, nutritional condition, and summer residency of individual females. Old females and those in good nutritional condition risked encountering severe weather by delaying autumn migration, and were thus risk-prone with respect to the potential loss of foraging opportunities in deep snow compared with young females and those in poor nutritional condition. Females that summered on the west side of the crest of the Sierra Nevada delayed autumn migration relative to east-side females, which supports the influence of the local environment on timing of migration. In contrast, timing of spring migration was unrelated to individual life-history characteristics, was nearly twice as synchronous as autumn migration, differed among years, was related to the southern oscillation index, and was influenced by absolute snow depth and advancing phenology of plants. Plasticity in timing of migration in response to climatic conditions and plant phenology may be an adaptive behavioral strategy, which should reduce the detrimental effects of trophic mismatches between resources and other life-history events of large herbivores. Failure to consider effects of nutrition and other life-history traits may cloud interpretation of phenological patterns of mammals and conceal relationships associated with climate change.

California↗

USGS2022

Spatial personalities: A meta-analysis of consistent individual differences in spatial behavior

Individual variation in behavior, particularly consistent among-individual differences (i.e., personality), has important ecological and evolutionary implications for population and community dynamics, trait divergence, and patterns of speciation. Nevertheless, individual variation in spatial behaviors, such as home range behavior, movement characteristics, or habitat use has yet to be incorporated into the concepts or methodologies of ecology and evolutionary biology. To evaluate evidence for the existence of consistent among-individual differences in spatial behavior – which we refer to as “spatial personality” – we performed a meta-analysis of 200 repeatability estimates of home range size, movement metrics, and habitat use. We found that the existence of spatial personality is a general phenomenon, with consistently high repeatability (r) across classes of spatial behavior (r = 0.67–0.82), taxa (r = 0.31–0.79), and time between repeated measurements (r = 0.54–0.74). These results suggest: 1) repeatable spatial behavior may either be a cause or consequence of the environment experienced and lead to spatial personalities that may limit the ability of individuals to behaviorally adapt to changing landscapes; 2) interactions between spatial phenotypes and environmental conditions could result in differential reproduction, survival, and dispersal, suggesting that among-individual variation may facilitate population-level adaptation; 3) spatial patterns of species' distributions and spatial population dynamics may be better understood by shifting from a mean field analytical approach towards methods that account for spatial personalities and their associated fitness and ecological dynamics.

Behavioral Ecology↗

USGS2010

Emerging viral diseases of fish and shrimp

The rise of aquaculture has been one of the most profound changes in global food production of the past 100 years. Driven by population growth, rising demand for seafood and a levelling of production from capture fisheries, the practice of farming aquatic animals has expanded rapidly to become a major global industry. Aquaculture is now integral to the economies of many countries. It has provided employment and been a major driver of socio-economic development in poor rural and coastal communities, particularly in Asia, and has relieved pressure on the sustainability of the natural harvest from our rivers, lakes and oceans. However, the rapid growth of aquaculture has also been the source of anthropogenic change on a massive scale. Aquatic animals have been displaced from their natural environment, cultured in high density, exposed to environmental stress, provided artificial or unnatural feeds, and a prolific global trade has developed in both live aquatic animals and their products. At the same time, over-exploitation of fisheries and anthropogenic stress on aquatic ecosystems has placed pressure on wild fish populations. Not surprisingly, the consequence has been the emergence and spread of an increasing array of new diseases. This review examines the rise and characteristics of aquaculture, the major viral pathogens of fish and shrimp and their impacts, and the particular characteristics of disease emergence in an aquatic, rather than terrestrial, context. It also considers the potential for future disease emergence in aquatic animals as aquaculture continues to expand and faces the challenges presented by climate change.

Veterinary Research↗

USGS1993

Influence of Pb on microbial activity in Pb-contaminated soils

Investigations of the influence of Pb on soil microbial communities have focused on Pb concentrations of 1 g kg-’ or less (Barkay et al., 1985; Capone et al., 1983; Chang and Broadbent, 1981; Doelman and Haanstra, 1979; Trevors et al., 1985). However, a number of environments exist in which Pb concentrations exceed 1 g kg-’ dry soil (Davenport and Peryea, 1991; Davis et al., 1992; Bisessar, 1982). Bisessar (1982) reported an inverse correlation between Pb concentration and the bacterial population size in soil near a secondary lead smelter. However, similar trends in the concentrations of Pb, As, Cd, and Cu at the site make it difficult to attribute the reductions in population size to Pb alone. Although the effects on microbial carbon mineralization of Pb concentrations as high as 20,000 g kg-’ dry soil were investigated by Debosz et a/. (1985), differences in pH between Pb treatments and the lack of controls for abiotic CO, evolution make the results of the study equivocal. Our purpose was to examine the effects of g kg-’ Pb concentrations on the growth and productivity of soil microbial communities.

Soil Biology and Biochemistry↗

USGS2019

Main stem and off-channel habitat use by juvenile Chinook salmon in a sub-Arctic riverscape

Poor growth and survival in freshwater and marine environments have been implicated as responsible for Chinook salmon ( Oncorhynchus tshawytscha ) declines across Alaska. Lateral connectivity of river main stems with off-channel habitats may play an integral role in sustaining Alaskan salmonid populations because off-channel habitats commonly provide greater growth opportunities than main stem habitats through greater macroinvertebrate productivity and warmer water temperatures. However, off-channel habitats may impose greater mortality risks to juvenile salmonids, as these habitats are typically more susceptible to drying and are often occupied by potential predators. We used a hierarchical Bayesian count model to describe juvenile Chinook salmon distributions throughout the Chena River, Alaska in main stem and off-channel habitats and employed diet, prey availability, and bioenergetic analyses to explain these habitat selection decisions from data collected in the summer of 2015. We found salmon to be most abundant in off-channel habitats as summer temperature increased, which suggested that salmon dispersed to off-channel habitats to take advantage of energetically favourable growth conditions as indicated by the higher prey biomass in benthic and diet samples collected within off-channel habitats. Our results could have significant implications for juvenile salmon under a warming Alaskan climate as access to productive off-channel habitats may be important to offset increased energetic costs as temperature warms.

Alaska↗

USGS2023

Ecological associations of non-native ungulates on the Hawaiian Island of Lāna‘i

Sustained-yield hunting of introduced ungulates in the Hawaiian Islands often conflicts with the conservation of native species, but there is little reliable data to guide effective management. European mouflon sheep ( Ovis musimon ; mouflon) and axis deer ( Axis axis ; deer) were introduced on the island of Lāna‘i to provide additional hunting opportunities. Managers will require better information regarding the ecological associations of introduced ungulate species, relative to the habitats occupied, to resolve longstanding conflicts between native species conservation and sustained-yield hunting on islands. To address this information need, we modeled sheep and deer ecological associations, habitat-use, and suitability using data obtained from an intensive aerial survey completed in 2013 and temporally matching environmental data. In habitat suitability models evaluated by Receiver Operating Characteristic (ROC) metrics, predictor importance in a generalized linear model (GLM) of deer decreased in the following order: afternoon cloud cover, topographic slope, mean annual precipitation (MAP), elevation, normalized difference vegetation index (NDVI), and bare soil index. In a random GLM model of mouflon, predictor importance decreased in the following order: afternoon cloud cover, deer habitat suitability, NDVI, bare soil index, topographic slope, elevation, and MAP. Mouflon were restricted to lower elevation arid slopes, whereas deer were more broadly distributed throughout upland environments of the island. The presence of deer was also an important predictor for mouflon distribution, although mouflon was not an important predictor of deer, suggesting asymmetrical competition. Removal of the more abundant deer population may lead to an increase in abundance and distribution of mouflon without containment. This work represents the first habitat suitability analysis for all nonnative ungulates on any entire Hawaiian island. Our results are applicable to other islands where conflicts may arise with introduced ungulates, sustained-yield hunting, and native species conservation.

Hawaii↗

USGS2016

Landscapes of West Africa: A window on a changing world

Our global ecosystem is and has always been complex, dynamic, and in constant flux. Science tells us how natural forces of enormous power have shaped and reshaped Earth’s surface, atmosphere, climate, and biota again and again since the planet’s beginnings about 4.5 billion years ago. For most of the planet’s history those environmental changes were the result of the interaction of natural processes such as geology and climate and were described on the geological time scale in epochs spanning millions of years. When humankind appeared on Earth around 200,000 years ago the influence of human activity on the environment must have been small and localized. The influence of scattered small groups of people on the global ecosystem would have been overwhelmed by the forces of natural systems (Steffen and others, 207). Human population would not grow to 50 million (about 0.7 percent of the Earth’s current population) for another 197,000 years. Population growth accelerated over the centuries that followed until the planet was adding more than that 50 million people every year. Our planet is now home to roughly 7.3 billion people and we are adding 1 million more people roughly every 4.8 days (US Census Bureau, 2011). Before 1950, no one on Earth had lived through a doubling of the human population, but now some people have experienced a tripling in their lifetime (Cohen, 2003).

Book↗

USGS2019

White-tailed deer movements and space use on Fire Island: A four-year radio-telemetry study 2015-2016 post-Hurricane Sandy assessment

Hurricane Sandy provided a unique opportunity to better understand the movements of Fire Island’s dense white-tailed deer (Odocoileus virginianus borealis) herds. White-tailed deer inhabit all areas of Fire Island National Seashore and their high densities negatively affect native vegetation in several areas of the island, especially as disturbed areas attempt to recover after a catastrophic storm like Hurricane Sandy. Understanding deer movements and space use helps land managers to prioritize white-tailed deer population size and the health and recovery potential of Fire Island’s natural lands according to their management goals. The results of this study will inform Fire Island staff as they prepare to initiate the tasks set forth by the Seashore’s approved Deer Management Plan. We used radio-collars fitted with Very High Frequency (VHF) signal and Global Positioning System (GPS) technology to monitor movements of white-tailed deer for four years after Hurricane Sandy. The greatest movements of Fire Island’s adult female white-tailed deer occurred in spring each year. Home range and core area sizes varied among study areas and years, but suggested hierarchical dominance among Fire Island’s deer populations. Potentially six distinct populations were delineated through analysis of GPS radio-collar data, though these divisions also reflect the concentrated sampling efforts of deer capture. Nearly all deer monitored shared time between natural and nearby built environments. Since Hurricane Sandy, deer movements in Fire Island’s Wilderness are divided by the storm-induced breach. GPS radio-collars provided a wealth of data for analysis of deer movements and space use, and this report is simply a snapshot of the potential information we intend to gain from this study.

New York↗

USGS2015

California State Waters Map Series — Offshore of San Francisco, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of San Francisco map area is centered on the City of San Francisco and the Golden Gate channel, a waterway that connects the Pacific Ocean to the San Francisco Bay between the Marin Headlands and San Francisco Peninsula. The San Francisco Bay Area is the second-largest urban area on the U.S. West Coast with a combined population of over seven million. The bay supports several major cargo ports and the Port of San Francisco’s Fisherman’s Wharf is a major center for Northern California’s commercial and sport fishing fleets. The coastal part of the map area predominantly consists of high bluffs and vertical sea cliffs shaped by uplift and erosion of the Marin Headlands and San Francisco Peninsula east of the San Andreas and San Gregorio Fault Zones. The seafloor in the map area extends from the shoreline and western end of the Golden Gate channel to water depths of about 30 to 50 m, except for the San Andreas graben area, where water depths reach 75 m. Sea-level rise, tidal currents, and tectonics have shaped bathymetry in the map area. During the Last Glacial Maximum, Sea level was about 125 m lower than present day and the shoreline was more than 45 km west of San Francisco near the Farallon Islands. At that time, the map area was part of a large alluvial plain connected to a drainage basin that included much of California’s Central Valley. A river system flowed westward through the narrows of the Golden Gate channel and an alluvial valley bounded to the north and south by bedrock highlands, including the present-day Pacifica-Pescadero and Bolinas shelves. Rising seas entered the Golden Gate about 11,000 to 10,000 years ago and subsequent marine flooding led to progressive growth of the San Francisco Bay. Strong tidal currents, accelerating through the relatively narrow Golden Gate, have scoured the bedrock channel to a depth of 113 m. East and west of the channel, tidal currents decelerate and form large fields of sand waves. Offshore of the Marin Headlands, eastward transfer of right-lateral fault slip in a complex of faults northwest of the map area has caused extension and the formation of a sediment basin called the San Andreas graben on the continental shelf. The accommodation space created by extension on the shelf and the proximity to sediment transported to the ocean through San Francisco Bay results in a sand-dominated offshore shelf environment. Seafloor habitats in the Offshore of San Francisco map area comprise significant sand-dominated sediment habitat with sand wave and ripple bedforms indicative of high wave and current energy. North of the Golden Gate, biological productivity resulting from coastal upwelling supports populations of Sooty Shearwater, Western Gull, Common Murre, Cassin’s Auklet, and many other less populous bird species. In addition, an observable recovery of Humpback and Blue Whales has occurred in the area; both species are dependent on coastal upwelling to provide nutrients. For the first time in 65 years, Pacific Harbor Porpoise returned to San Francisco Bay in 2009. On the coast north of the Golden Gate, the large extent of exposed inner shelf bedrock supports large forests of “bull kelp,” which is well adapted for high wave-energy environments. Common fish species found in the kelp beds and rocky reefs include painted greenling, kelp greenling, lingcod, and several varieties of rockfish. Circulation over the continental shelf in the Offshore of San Francisco map area is dominated by the southward-flowing California Current, an eastern limb of the North Pacific Gyre that flows from Oregon to Baja California. At its midpoint offshore of central California, the California Current transports subarctic surface waters southeastward, about 150 to 1,300 km from shore. Seasonal northwesterly winds that are, in part, responsible for the California Current, generate coastal upwelling. Ocean temperatures offshore of central California have increased over the past 50 years, driving an ecosystem shift from the productive subarctic regime towards a depopulated subtropical environment.

California↗

USGS2021

Non-native Pond Sliders cause long-term decline of native Sonora Mud Turtles: A 33-year before-after study in an undisturbed natural environment

Using a before-after study design in a stable, largely undisturbed pond habitat and a dataset spanning 33 years, we document and describe the decline of native Sonora mud turtles (Kinosternon sonoriense) after the introduction of non-native pond sliders (Trachemys scripta). The Sonora mud turtle population in Montezuma Well in central Arizona, USA, declined to less than 25% of previous numbers, from 372 ± 64 in 1983 to 80 ± 21 in 2011. We trapped and removed the non-native turtles between 2007 and 2012 and after removal of the non-natives, the Sonora mud turtle population increased to 139 ± 34 in 2015. The native turtles also significantly increased basking activity after removal of the non-natives, paralleling results of small-scale mesocosm studies showing that pond sliders negatively affect basking rates of native turtle species. Reproductive rates of female Sonora mud turtles (numbers of females with eggs) were lower during the period of peak non-native turtle abundance, and increased after removal of the non-native turtles. We hypothesize that the reduction in effective reproductive rate links interference competition (reflected in reduced basking rates) to the long-term decline of the native mud turtles. Results from the undisturbed natural system of Montezuma Well provide new insights on the overall occurrence, magnitude, and mechanisms of negative effects of introduced pond sliders on native turtle species. Sonora mud turtles are very different in their morphology, behavior, and ecology from pond sliders and from native turtles in other studies, suggesting that impacts of non-native pond sliders are more pervasive than previously thought.

Aquatic Invasions↗

USGS2023

Viability of side-scan sonar to enumerate Paddlefish, a large pelagic freshwater fish, in rivers and reservoirs

Recreational-grade side-scan sonar (SSS) has become an invaluable tool for inland fisheries, particularly when characterizing underwater habitat, but it is being increasingly used for enumerating large-bodied (> 1 m total length [TL]) aquatic fauna. We used SSS in river and reservoir environments to evaluate methods for identifying and counting Paddlefish Polyodon spathula , a large pelagic planktivore of recreational and economic importance that can exceed 2 m in length and weigh over 70 kg. We assessed accuracy and precision among readers to identify Paddlefish by assigning confidence scores (1–3; with 3 being more confident) to sonar images of a ballistics-gel filled fiberglass replica Paddlefish. Readers varied in their confidence scores for the replica Paddlefish and no reader could identify the target beyond 25 m from the transducer. Afterwards, we used SSS to survey several kilometers of a reservoir during summer residency and a large river during springtime spawning migrations. Two readers counted Paddlefish images in the SSS recordings and we estimated population size in the surveyed area with distance sampling. In the reservoir, the number of Paddlefish counted ranged from 172 to 184. In the river, the number of Paddlefish counted ranged from 165 to 617. The exponential model of distance was most-supported for detection in both environments, except there was support for a half-norm distribution for one reader in the river. In the reservoir, abundance estimates were statistically similar between readers at approximately 1500 (7/ha) in the total scanned area. In the river, similar abundance estimates were obtained with the half-norm model from one reader compared to the exponential model of the other reader, resulting in approximately 1500 individuals (30/ha) in the surveyed area. The application of SSS to count Paddlefish has some clear advantages to traditional methods, such as gill netting, and can be done at multiple times of the year. Distance sampling methods compensated for differences in counts among readers, indicating distance sampling can produce similar abundance estimates even when variation in counts exists among readers.

Oklahoma↗

USGS2004

Epidemiology of fractures in people with severe and profound developmental disabilities

Fractures are more prevalent among people with severe and profound developmental disabilities than in the general population. In order to characterize the tendency of these people to fracture, and to identify features that may guide the development of preventive strategies, we analyzed fracture epidemiology in people with severe and profound developmental disabilities who lived in a stable environment. Data from a 23-year longitudinal cohort registry of 1434 people with severe and profound developmental disabilities were analyzed to determine the effects of age, gender, mobility, bone fractured, month of fracture, and fracture history upon fracture rates. Eighty-five percent of all fractures involved the extremities. The overall fracture rate increased as mobility increased. In contrast, femoral shaft fracture risk was substantially higher in the least mobile [relative risk (RR), 10.36; 95% confidence interval (CI), 3.29-32.66] compared with the most mobile group. Although the overall fracture rate was not associated with age, the femoral shaft fractures decreased but hand/foot fractures increased with age. Overall fracture risk declined in August and September (RR, 0.70; 95% CI, 0.55-0.89), being especially prominent for tibial/fibular fractures (RR, 0.31; 95% CI, 0.13-0.70). Gender was not a factor in fracture risk. Two primary fracture mechanisms are apparent: one, largely associated with lack of weight-bearing in people with the least mobility, is exemplified by femoral fractures during non-traumatic events as simple as diapering or transfers; the other, probably due to movement- or fall-related trauma, is exemplified by hand/foot fractures in people who ambulate. The fracture experience of people with severe and profound developmental disabilities is unique and, because it differs qualitatively from postmenopausal osteoporosis, may require population-specific methods for assessing risk, for improving bone integrity, and for reduction of falls and accidents. ?? International Osteoporosis Foundation and National Osteoporosis Foundation 2004.

Osteoporosis International↗