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At least 253 records · Page 14Linked to original sources
USGS2022

Trends in groundwater levels, and orthophosphate and nitrate concentrations in the Middle Snake River Region, south-central Idaho

The U.S. Geological Survey (USGS) evaluated nitrate and orthophosphate concentrations in groundwater for temporal trends (monotonic and step trends) for the middle Snake River region (Cassia, Gooding, Jerome, Lincoln, Minidoka, and Twin Falls Counties) in south-central Idaho using the Regional Kendall test (monotonic trends) and the Wilcoxon signed rank test (step trends). The study evaluated two trend periods: 2000–09 and 2010–19/20. The study area was divided into six hydrogeologic zones (HZs) that had similar geologic and hydrologic characteristics and that correlated with county boundaries where possible. Two well networks sampled by the USGS National Water Quality Program within the HZs were also evaluated. The northern Gooding County HZ had statistically significant increasing nitrate concentration trends for both the monotonic and step trends in the early trend period, while the Cassia and Jerome/Southern Gooding County HZs only had one of the statistical tests with statistically significant increasing nitrate concentrations. The Minidoka County HZ had conflicting results between the two statistical tests for the early time period with a statistically significant increasing monotonic trend in nitrate concentration and a statistically significant decreasing step trend. The differing results between these two statistical tests indicates the significance of concentration data during the middle of the time period. Both the Lincoln and Twin Falls County HZs did not have statistically significant trends for either test during either time period as well as the Northern Gooding County HZ for the latter time period. The Minidoka County HZ had statistically significant nitrate trends for both tests in the latter time period along with one of the trend tests for the Cassia and Jerome/Southern Gooding County HZ. Most of the nitrate concentration trend rates are low from 0.01 to 0.12 milligram per liter per year (mg/L/year) with the northern Gooding County HZ having the highest trend rate during the early time period of 0.28 mg/L/year for the step trend and 0.55 mg/L/year for the monotonic trend. All the HZs and both well networks had statistically significant increasing orthophosphate-concentrations trends in groundwater for the early time period except for the Lincoln County HZ and the step-trend for the Minidoka County HZ. Orthophosphate concentration trend rates for the early period were low, ranging from 0.001 to 0.015 mg/L/year. Only two HZs and the well networks had enough orthophosphate concentration data available in the latter time period to do statistical analysis. The two HZs (Minidoka and Southern Gooding/Jerome County) both have decreasing orthophosphate concentration trends, with only the monotonic trend for the Southern Gooding/Jerome County HZ being statistically significant at 90 percent with a rate of −0.001 mg/L/year. Groundwater levels in two well networks in the eastern Snake River Plain aquifer were also evaluated for trends (monotonic and step), with both networks having statistically significant declining groundwater levels for the 1993–2009 trend period. The latter trend period (2010–20) had statistically significant declining groundwater levels for the A&B well network and statistically significant increasing groundwater levels for the Jerome/Gooding well network, which is downgradient from an aquifer recharge area.

Idaho↗
USGS2024

Ophidiomycosis (snake fungal disease) case definition for wildlife

Diagnostic laboratories receive carcasses and samples for diagnostic evaluation and pathogen/toxin detection. Case definitions bring clarity and consistency to the evaluation process. Their use within and between organizations allows more uniform reporting of diseases and etiologic agents. The intent of a case definition is to provide scientifically based criteria for determining (a) if an individual carcass has a specific disease and degree of confidence in that diagnosis and (b) if there is evidence of a pathogen or toxin in a carcass or sample (for example, swab, tissue sample, skin scraping, blood/serum sample, environmental sample, or other). This case definition is specific to Ophidiomycosis (snake fungal disease) and applies to all snakes.

Techniques and Methods↗
USGS2003

Diffusion and drive-point sampling to detect ordnance-related compounds in shallow ground water beneath Snake Pond, Cape Cod, Massachusetts, 2001-02

Diffusion samplers and temporary drive points were used to test for ordnance-related compounds in ground water discharging to Snake Pond near Camp Edwards at the Massachusetts Military Reservation, Cape Cod, MA. The contamination resulted from artillery use and weapons testing at various ranges upgradient of the pond.The diffusion samplers were constructed with a high-grade cellulose membrane that allowed diffusion of explosive compounds, such as RDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine) and HMX (Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), into deionized water inside the samplers. Laboratory tests confirmed that the cellulose membrane was permeable to RDX and HMX. One transect of 22 diffusion samplers was installed and retrieved in August-September 2001, and 12 transects with a total of 108 samplers were installed and retrieved in September-October 2001. The diffusion samplers were buried about 0.5 feet into the pond-bottom sediments by scuba divers and allowed to equilibrate with the ground water beneath the pond bottom for 13 to 27 days before retrieval. Water samples were collected from temporary well points driven about 2-4 feet into the pond bottom at 21 sites in December 2001 and March 2002 for analysis of explosives and perchlorate to confirm the diffusion-sampling results. The water samples from the diffusion samplers exhibited numerous chromatographic peaks, but evaluation of the photo-diode-array spectra indicated that most of the peaks did not represent the target compounds. The peaks probably are associated with natural organic compounds present in the soft, organically enriched pond-bottom sediments. The presence of four explosive compounds at five widely spaced sites was confirmed by the photo-diode-array analysis, but the compounds are not generally found in contaminated ground water near the ranges. No explosives were detected in water samples obtained from the drive points. Perchlorate was detected at less than 1 microgram per liter in two drive-point samples collected at the same site on two dates about 3 months apart. The source of the perchlorate in the samples could not be related directly to other contamination from Camp Edwards with the available information. The results from the diffusion and drive-point sampling do not indicate an area of ground-water discharge with concentrations of the ordnance-related compounds that are sufficiently elevated to be detected by these sampling methods. The diffusion and drive-point sampling data cannot be interpreted further without additional information concerning the pattern of ground-water flow at Snake Pond and the distributions of RDX, HMX, and perchlorate in ground water in the aquifer near the pond.

Massachusetts↗
USGS1914

Profile surveys in Snake River basin, Idaho

Snake River, the largest tributary of the Columbia, rises among the high peaks of the Rocky Mountains in Yellowstone National Park, heading in the divide from which streams flow northward and eastward into the Missouri, southward to the Colorado and the lakes of the Great Basin, and westward to the Columbia. From the headwater region, including Shoshone, Lewis, and Heart lakes, in Yellowstone National Park, the river flows southward, broadening into Jackson Lake (4 miles wide and 18 miles long) and passing through Jackson Valley (8 miles wide and 40 miles long), beyond which, near the Idaho-Wyoming line, it enters a long canyon. At the south edge of Madison County, Idaho, it receives Henrys Fork, below which the Snake flows southward and westward across Idaho to a point near Homedale, near the Oregon-Idaho line, where it turns abruptly northward and beyond which it forms for about 170 miles the boundary between Idaho and Oregon and for 30 miles more that between Idaho and Washington. It enters Washington at Lewiston, flows northwest, west, and southwest, and joins the Columbia near Pasco.

Idaho;Nevada;Oregon;Utah;Washington;Wyoming↗
USGS2015

Seasonal dynamics of zooplankton in Columbia–Snake River reservoirs,with special emphasis on the invasive copepod Pseudodiaptomus forbesi

The Asian copepod Pseudodiaptomus forbesi has recently become established in the Columbia River. However, little is known about its ecology and effects on invaded ecosystems. We undertook a 2-year (July 2009 to June 2011) field study of the mesozooplankton in four reservoirs in the Columbia and Snake Rivers, with emphasis on the relation of the seasonal variation in distribution and abundance of P. forbesi to environmental variables. Pseudodiaptomus forbesi was abundant in three reservoirs; the zooplankton community of the fourth reservoir contained no known non-indigenous taxa. The composition and seasonal succession of zooplankton were similar in the three invaded reservoirs: a bloom of rotifers occurred in spring, native cyclopoid and cladoceran species peaked in abundance in summer, and P. forbesi was most abundant in late summer and autumn. In the uninvaded reservoir, total zooplankton abundance was very low year-round. Multivariate ordination indicated that temperature and dissolved oxygen were strongly associated with zooplankton community structure, with P. forbesi appearing to exhibit a single generation per year . The broad distribution and high abundance of P. forbesi in the Columbia–Snake River System could result in ecosystem level effects in areas intensively managed to improve conditions for salmon and other commercially and culturally important fish species.

Columbia River, Snake River↗
USGS2025

Reproductive condition of an invasive snake in urban, savanna, and forest habitats

Predation by Brown Treesnakes ( Boiga irregularis ) has caused the decline or extinction of all native forest vertebrates on Guam, including birds, lizards, and bats. Loss of the highest-quality prey has caused shifts in Brown Treesnake size and life history. We sought to understand how reproductive condition varies among habitats island-wide, particularly comparing urban and savanna habitats (where some primarily non-native large prey remain) with prey-depauperate forest habitats. We dissected 100 snakes from each of 18 sites stratified by 6 habitat types and calculated a body condition index, relative follicle size (for females; N = 817) and relative testes size (for males; N = 992) for each. Low detection of reproductive females continues to hamper research on their biology, as only 11% of females had secondary vitellogenic follicles (N = 89). Although variation among sites within habitats was high, above-average reproductive development of both males and females was most frequently observed in urban and savanna habitats, emphasizing the potential for prey subsidies in these habitats to fuel population growth and affect invasive snake management objectives. Furthermore, the trade-off between body condition and reproductive condition appeared to be more severe in forested habitats and less severe in urban habitats for both males and females. There were few obvious seasonal patterns, although there was a slightly lower probability of females having secondary vitellogenic follicles in the wet season compared to the dry season.

NeoBiota↗
USGS1990

Risks to infants from bites of the brown tree snake (Boiga irregularis)

The brown tree snake, Boiga irregularis , is abundant on Guam and commonly invades human habitations. Data on emergency room visits on Guam document a high freguency of snakebites on Guam. Over 50% of the emergency room visits for snakebite involved children <4 years old. Records exist of 4 infants, 1, 2, 5, and 10 months old, who displayed significant symptoms after being bitten, while sleeping, by snakes. Two infants developed respiratory problems within a few hours and required medical treatment for asphyxiation. Lethargy, diminished sensory perceptions, drooping eyelids, swelling, discoloration, and bleb formation were variable in occurrence in the patients.

American Journal of Tropical Medicine and Hygiene↗
USGS1996

Trouble in paradise: The brown tree snake in the western Pacific

The brown treesnake (Boiga irregularis) was recognized as a pest species by Congress in Section 1209 of the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 (NANPCA). Like aquatic pests, tree snakes are sometimes dispersed by ships, have wide-ranging effects on natural and human communities, and threaten to spread to other areas. The problems they are causing on Guam, a formerly snake-free island, are unusual in that they involve many aspects of the biota of Guam and directly affect the human residents of the island.

Aquatic Nuisance Species Digest↗
USGS2009

Indigo snake capture methods: effectiveness of two survey techniques for Drymarchon couperi in Georgia

Drymarchon couperi (Eastern Indigo Snake), a federally threatened species of the southeastern Coastal Plain, has presented challenges for surveyors, with few reliable methods developed for its detection or monitoring. Surveys for D. couperi at potential underground shelters conducted in late fall through early spring have been relatively successful when conducted by experienced surveyors, especially in the northern portions of the range. However, trapping efforts for D. couperi conducted throughout the range have met with limited success. To further evaluate detection methods, we conducted trapping and surveying from December 2002 to April 2004 in areas known to support D. couperi in southeastern Georgia. We captured 18 D. couperi through surveys of potential underground shelters from December 2002 to March 2003 (14 person-hours per capture) and six individuals through trapping (141 trap days or 27 in-field person-hours per capture). Trapping was most successful during early fall, a period when surveys are often less effective compared to those conducted in late fall through early spring. We recommend a combination of surveys from mid-fall through March in conjunction with trapping, especially from late-summer through fall in the northern portions of the snake?s range. We also recommend further experimentation with alternative trap designs and survey methods for D. couperi.

Florida Scientist↗
USGS2012

An experimental evaluation of potential scavenger effects on snake road mortality detections

As road networks expand and collisions between vehicles and wildlife become more common, accurately quantifying mortality rates for the taxa that are most impacted will be critical. Snakes are especially vulnerable to collisions with vehicles because of their physiology and behavior. Reptile road mortality is typically quantified using driving or walking surveys; however, scavengers can rapidly remove carcasses from the road and cause underestimation of mortality. Our objective was to determine the effect that scavengers might have had on our ability to accurately detect reptile road mortality during over 150 h and 4,000 km of driving surveys through arid shrublands in southwest Wyoming, which resulted in only two observations of mortality. We developed unique simulated snake carcasses out of Burbot (Lota lota), a locally invasive fish species, and examined removal rates across three different road types at three study sites. Carcass size was not a significant predictor of time of removal, and carcass removal was comparable during the daytime and nighttime hours. However, removal of simulated carcasses was higher on paved roads than unpaved or two-track roads at all study sites, with an average of 75% of the carcasses missing within 60 h compared to 34% and 31%, respectively. Scavengers may therefore negatively impact the ability of researchers to accurately detect herpetofaunal road mortality, especially for paved roads where road mortality is likely the most prevalent.

Wyoming↗
USGS2010

Snake River Fall Chinook Salmon life history investigations annual report, 2009

In 2009, we used radio and acoustic telemetry to evaluate the migratory behavior, survival, mortality, and delay of subyearling fall Chinook salmon in the Clearwater River and Lower Granite Reservoir. We released a total of 1,000 tagged hatchery subyearlings at Cherry Lane on the Clearwater River in mid August and we monitored them as they passed downstream through various river and reservoir reaches. Survival through the free-flowing river was high (>0.85) for both radio- and acoustic-tagged fish, but dropped substantially as fish delayed in the Transition Zone and Confluence areas. Estimates of the joint probability of migration and survival through the Transition Zone and Confluence reaches combined were similar for both radio- and acoustic-tagged fish, and ranged from about 0.30 to 0.35. Estimates of the joint probability of delaying and surviving in the combined Transition Zone and Confluence peaked at the beginning of the study, ranging from 0.323 (SE =NA; radio-telemetry data) to 0.466 (SE =0.024; acoustic-telemetry data), and then steadily declined throughout the remainder of the study. By the end of October, no live tagged juvenile salmon were detected in either the Transition Zone or the Confluence. As estimates of the probability of delay decreased throughout the study, estimates of the probability of mortality increased, as evidenced by the survival estimate of 0.650 (SE =0.025) at the end of October (acoustic-telemetry data). Few fish were detected at Lower Granite Dam during our study and even fewer fish passed the dam before PIT-tag monitoring ended at the end of October. Five acoustic-tagged fish passed Lower Granite Dam in October and 12 passed the dam in November based on detections in the dam tailrace; however, too few detections were available to calculate the joint probabilities of migrating and surviving or delaying and surviving. Estimates of the joint probability of migrating and surviving through the reservoir was less than 0.2 based on acoustic-tagged fish. Migration rates of tagged fish were highest in the free-flowing river (median range = 36 to 43 km/d) but were generally less than 6 km/d in the reservoir reaches. In particular, median migration rates of radio-tagged fish through the Transition Zone and Confluence were 3.4 and 5.2 km/d, respectively. Median migration rate for acoustic-tagged fish though the Transition Zone and Confluence combined was 1 km/d. We radio tagged 84 smallmouth bass and six channel catfish in the Confluence reach and later detected 48 bass and 1 catfish during mobile tracking. Predators were primarily located along shorelines in the Confluence, but a couple of smallmouth bass did swim into the Clearwater River. Most radio-tagged subyearlings that we determined to be dead were also located in shoreline areas suggesting that predation could account for some of the mortality we observed. Our total dissolved gas (TDG) monitoring in the lower Clearwater River showed a cyclic pattern of low (~102%) TDG in the morning and higher (~110%) TDG in the late afternoon. Using a compensation depth of 1 m, we found that 15.4% (3.9 ha) of the lower 13 km of the Clearwater River would not provide fish with an opportunity for depth compensation in a low flow year. Water temperatures in the Clearwater River showed diel variations of about 2°C, and generally ranged from 10-12°C during summer flow augmentation. The Clearwater River generally showed little thermal variation while our tagged fish were at large, whereas the Snake River at the downstream boundary of the Confluence was thermally heterogeneous until mid-September. In the unimpounded Clearwater River, simulated water velocities ranged from about 1.3 to 1.5 m/s before flow augmentation ended, and were about 0.6 m/s thereafter. By comparison, velocities at the Clearwater River mouth were about 0.3 m/s during flow augmentation, and about 0.1 m/s thereafter. From October 2008 to February 2009 and from July 2009 to March 2010 we used monthly mobile hydroacoustic surveys to estimate the number of juvenile Chinook salmon in Little Goose and Lower Granite reservoirs, the first two reservoirs encountered on the lower Snake River by downstream migrants. Concurrent lampara seining was used to verify acoustic targets, calculate condition factors, and to examine spatial and temporal density patterns. Our data indicated that holdovers are larger in warmer water temperature years and smaller in colder water temperature years. Lampara catch data indicated that holdovers were seasonally the most abundant and in the best condition in November and December, whereas the hydroacoustic data showed population peaks in October in Lower Granite Reservoir and in January in Little Goose Reservoir. Maximum population estimates in Lower Granite Reservoir were 6,929 in October 2008 and 7,218 in October 2009. In Little Goose Reservoir, maximum population estimates were 9,645 in January 2009 and 10,419 in January 2010. By February, abundances and relative condition factors decreased as most holdovers had probably moved past Lower Granite and Little Goose dams. Spatial differences were primarily longitudinal with greater holdover abundances in the lower reaches of both reservoirs.

Report↗
USGS2012

The ICDP Snake River Geothermal Drilling Project: preliminary overview of borehole geophysics

Hotspot: The Snake River Geothermal Drilling Project was undertaken to better understand the geothermal systems in three locations across the Snake River Plain with varying geological and hydrological structure. An extensive series of standard and specialized geophysical logs were obtained in each of the wells. Hydrogen-index neutron and γ-γ density logs employing active sources were deployed through the drill string, and although not fully calibrated for such a situation do provide semi-quantitative information related to the ‘stratigraphy’ of the basalt flows and on the existence of alteration minerals. Electrical resistivity logs highlight the existence of some fracture and mineralized zones. Magnetic susceptibility together with the vector magnetic field measurements display substantial variations that, in combination with laboratory measurements, may provide a tool for tracking magnetic field reversals along the borehole. Full waveform sonic logs highlight the variations in compressional and shear velocity along the borehole. These, together with the high resolution borehole seismic measurements display changes with depth that are not yet understood. The borehole seismic measurements indicate that seismic arrivals are obtained at depth in the formations and that strong seismic reflections are produced at lithological contacts seen in the corresponding core logging. Finally, oriented ultrasonic borehole televiewer images were obtained over most of the wells and these correlate well with the nearly 6 km of core obtained. This good image log to core correlations, particularly with regards to drilling induced breakouts and tensile borehole and core fractures will allow for confident estimates of stress directions and or placing constraints on stress magnitudes. Such correlations will be used to orient in core orientation giving information useful in hydrological assessments, paleomagnetic dating, and structural volcanology.

Snake River↗
USGS2012

Snakes in the wrong places: Gordon Rodda’s career in invasive species research

When USGS research zoologist Gordon G. Rodda was a graduate student at Cornell University studying behavioral biology of alligators —or later, completing a post-doc at the Smithsonian Institute studying the social behavior of green iguanas in Venezuela or following that, as a statistics and sociobiology instructor at the University of Tennessee—he did not foresee that his professional future was in snakes. Lots of snakes, and in places they don’t belong.

Report↗
USGS1973

Accessory apatite from hybrid granitoid rocks of the southern Snake Range, Nevada

Analytical data, optical properties, and unit-cell parameters are presented for 24 samples of accessory apatites recovered from hybrid granitoid rocks of the southern Snake Range, Nev. A complete chemical analysis is given for one. In the Snake Creek-Williams Canyon outcrop area, where the hybrid rocks grade from granodiorite with 63 percent SiO 2 to a quartz monzonite with 76 percent SiO 2 within a horizontal distance of about 3 miles, abundance and crystal habit of the apatite change with rock chemistry. The apatite probably is slightly more than 90 mole percent fluorapatite in the most felsic rocks, slightly less in the most mafic. The range of F->OH substitution in apatite from this outcrop area is much smaller than in the coexisting biotites. Except for manganese, strontium, sodium, and the rare earths, there is very limited substitution for calcium in the crystal structure of these apatites. Apatites from the more mafic rocks tend to contain a lighter, more basic assemblage of rare earths, in agreement with results obtained for coexisting allanites, monazites, and zircons.

Nevada↗
USGS2007

Hydrology and geomorphology of the Snake River in Grand Teton National Park

The influence of significant tributaries that join the Snake River within 10 km of Jackson Lake Dam (JLD) mitigate some impacts resulting from nearly 100 years of flow regulation in Grand Teton National Park. I analyzed measured and estimated unregulated flow data for all segments of the study area by accounting for tributary flows. The magnitude of the 2-yr recurrence flood immediately downstream from JLD decreased 45% since 1958 relative to estimated unregulated flows, whereas that downstream from Buffalo Fork, the largest tributary, decreased 36%. There has been no long-term progressive geomorphic change on the Snake River resulting from dam regulation. I mapped the bankfull channel on four series of aerial photographs taken in 1945, 1969, 1990/1991, and 2002 and analyzed channel change in a geographic information system. Periods of low-magnitude floods (1945 to 1969) resulted in widespread deposition whereas periods of high-magnitude floods (1969 to 1990/1991 and 1990/1991 to 2002) resulted in widespread erosion; channels narrowed and widened by as much as 31%. I mapped three distinct deposits within the Holocene alluvial valley. The lower floodplain covers 3.5% of the mapped area in the form of abandoned channel and inset, channel-margin facies and has inundating recurrence intervals of one to two years. The upper floodplain covers 36% of the mapped area, is composed of abandoned channels and bars, is higher in elevation than the lower floodplain, and is inundated by floods with recurrence intervals greater than 10 years. The lowest Holocene terrace covers 35% of the mapped area and is approximately 1 m higher in elevation than the upper floodplain. Though the lowest terrace has not been inundated or built since 1945, the two floodplain deposits have been developing since before 1945. Flood magnitudes have decreased throughout the study area as a result of regulation, but these decreases are mitigated downstream from tributaries. Dam operations have not resulted in long-term progressive channel change or the development and abandonment of floodplain deposits. However, channel change is now dependant on the frequency of high-magnitude floods, and the frequency with which the two floodplains are inundated has been reduced.

Wyoming↗
USGS2020

Play fairway analysis in geothermal exploration: The Snake River plain volcanic province

The Snake River volcanic province (SRP) has long been considered a target for geothermal development. It overlies a thermal anomaly that extends deep into the mantle and represents one of the highest heat flow provinces in North America, but systematic exploration been hindered by lack of a conceptual model. Play Fairway Analysis (PFA) is a methodology adapted from the petroleum industry that integrates data at the regional or basin scale to define favorable plays for exploration in a systematic fashion. The success of play fairway analysis in geothermal exploration depends critically on defining a systematic methodology that is grounded in theory and adapted to the geologic and hydrologic framework of real geothermal systems. This study focused on identifying three critical resource parameters for exploitable hydrothermal systems in the Snake River Plain: heat source, reservoir and recharge permeability, and cap or seal. Data included in the compilation for Heat were heat flow, the distribution and ages of volcanic vents, groundwater temperatures, thermal springs and wells, helium isotope anomalies, and reservoir temperatures estimated using geothermometry. Permeability was derived from stress orientations and magnitudes, post-Miocene faults, and subsurface structural lineaments based on magnetic and gravity data. Data for Seal included the distribution of impermeable lake sediments and clay-seal associated with hydrothermal alteration below the regional aquifer. These data were used to compile Common Risk Segment (CRS) maps for Heat, Permeability and Seal, which were combined to create a Composite Common Risk Segment (CCRS) map for all of southern Idaho that reflects the risk associated with geothermal resource exploration and helps to identify favorable resource tracks. Our data suggests that important undiscovered geothermal resources may be located in several areas of the SRP, including the western SRP (associated with buried lineaments capped by lacustrine sediment), at lineament intersections in the central SRP, and along the margins of the eastern SRP. These blind resources are associated with temperatures sufficient to support electricity production, and may be exploitable with existing deep drilling technology. We are testing our methodology by drilling a geothermal test well in Camas Prairie, ID, confirm our predictions of permeability and reservoir temperature.

Idaho↗
USGS2022

Storeria occipitomaculata (Red-bellied Snake)

STORERIA OCCIPITOMACULATA (Red-bellied Snake). USA: LOUISIANA: St. Mary Parish: Bayou Teche National Wildlife Refuge (29.69425N, 91.46701W; WGS 84). 18 August 2022. William C. Carroll and Aidan G. Phillips. Verified by Coleman M. Sheehy III. Florida Museum of Natural History, University of Florida (UF 193423; photo voucher). Adult photographed in leaf litter in a wet bottomland hardwood forest with a mixed composition of hardwood trees and Dwarf Palmetto (Sabal minor). New parish record (Dundee and Rossman 1989. The Amphibians and Reptiles of Louisiana. Louisiana State University Press, Baton Rouge, Louisiana. 300 pp.). The snake was found 68.5 km to the east-southeast from the nearest other documented specimen in Vermilion Parish (UF 177730; Muse et al. 2016. Herpetol. Rev. 47:266). This record is the second documentation of S. occipitomaculata in a coastal Louisiana parish (Muse et al. 2016, op. cit.). These two recent findings challenge our previous understanding that this species is absent from coastal parishes (Boundy and Carr 2017. Amphibians & Reptiles of Louisiana: An Identification and Reference Guide. Louisiana State University Press, Baton Rouge, Louisiana. 282 pp.). Storeria occipitomaculata is fossorial and can be difficult to locate, but these two recent records suggest additional populations may yet be discovered where suitable forested habitat exists along the coast.

Louisiana↗
USGS2024

Overcoming low detectability in snake conservation research: Case studies from the Southeast USA

Goals of conservation research include detecting and monitoring changes in abundance, understanding species interactions, detecting extinction events of imperiled species, and detecting colonization events and spread of non-native species. Achieving these goals is difficult or impossible when the target species is rarely encountered or when the number of individuals detected is unrelated to the true population size, as is often the case with snakes. Here, we review the challenges that low species-level and individual-level detection probability cause for snake conservation research, present four case studies demonstrating approaches we have used to overcome low detection probability, and highlight priority areas for future research and method development.

Book chapter↗