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Geology topics

David C. Douglas

Publications and source records attributed to David C. Douglas.

At least 145 records · Page 8Linked to original sources
USGS2001

Effects of recent climate warming on caribou habitat and calf survival

Migratory Barren-Ground Caribou Rangifer tarandus granti are the most important subsistence resource for northern indigenous peoples. They are likely to respond to global climatic changes that affect the distribution of their forage resources and the availability of forage through the year. The Porcupine Caribou herd is a large, internationally migratory herd of about 128,000 individuals that occupies the Alaska-Canada borderlands and uses a 300,000 km 2 annual range. The calving ground is a traditionally-used portion of the annual range that comprises 23,000 km 2 at approximately 70° north. Caribou migrate several hundred kilometres from winter ranges to the calving ground, arriving in mid- to late-May each year. Calves are born during the first week of June, and cows and calves remain on the calving ground for 4-6 weeks before dispersing to late-summer, fall, and winter ranges. We measured the relative amount of green vegetation using data from polar orbiting satellites (Figure 1) to assess decade-long temporal trends in large scale habitat conditions on the calving ground and to investigate Caribou response to this habitat change. The vegetation index has shown a tendency toward earlier greening in spring and later plant senescence (dying off) in much of the northern hemisphere the 1980s, concurrent with independent estimates of climate change. High density calving was consistently located where the daily rate of increase in the amount of green plant biomass during lactation was greatest, in the period 1985-1996. This was probably because of the lactating cows' need for highly digestible new plant growth. Nutritional requirements of lactating cows are about double those during the remainder of the year.

Alaska, Yukon Territory↗
USGS2000

Classification methods for monitoring Arctic sea ice using OKEAN passive/active two-channel microwave data

This paper presents methods for classifying Arctic sea ice using both passive and active (2-channel) microwave imagery acquired by the Russian OKEAN 01 polar-orbiting satellite series. Methods and results are compared to sea ice classifications derived from nearly coincident Special Sensor Microwave Imager (SSM/I) and Advanced Very High Resolution Radiometer (AVHRR) image data of the Barents, Kara, and Laptev Seas. The Russian OKEAN 01 satellite data were collected over weekly intervals during October 1995 through December 1997. Methods are presented for calibrating, georeferencing and classifying the raw active radar and passive microwave OKEAN 01 data, and for correcting the OKEAN 01 microwave radiometer calibration wedge based on concurrent 37 GHz horizontal polarization SSM/I brightness temperature data. Sea ice type and ice concentration algorithms utilized OKEAN's two-channel radar and passive microwave data in a linear mixture model based on the measured values of brightness temperature and radar backscatter, together with a priori knowledge about the scattering parameters and natural emissivities of basic sea ice types. OKEAN 01 data and algorithms tended to classify lower concentrations of young or first-year sea ice when concentrations were less than 60%, and to produce higher concentrations of multi-year sea ice when concentrations were greater than 40%, when compared to estimates produced from SSM/I data. Overall, total sea ice concentration maps derived independently from OKEAN 01, SSM/I, and AVHRR satellite imagery were all highly correlated, with uniform biases, and mean differences in total ice concentration of less than four percent (sd<15%).

Remote Sensing of Environment↗
USGS2000

Seasonal movements and pelagic habitat use of Murres and Puffins determined by satellite telemetry

We tracked the movements of Common Murres ( Uria aalge ), Thick-billed Murres ( U. lomvia ), and Tufted Puffins ( Fratercula cirrhata ) using surgically implanted satellite transmitters. From 1994–1996, we tagged 53 birds from two colonies in the Gulf of Alaska (Middleton Island and Barren Islands) and two colonies in the Chukchi Sea (Cape Thompson and Cape Lisburne). Murres and puffins ranged 100 km or farther from all colonies in summer, but most instrumented birds had abandoned breeding attempts and their movements likely differed from those of actively breeding birds. However, murres whose movements in the breeding period suggested they still had chicks to feed foraged repeatedly at distances of 50–80 km from the Chukchi colonies in 1995. We detected no differences in the foraging patterns of males and females during the breeding season, nor between Thick-billed and Common Murres from mixed colonies. Upon chick departure from the northern colonies, male murres—some believed to be tending their flightless young—drifted with prevailing currents toward Siberia, whereas most females flew directly south toward the Bering Sea. Murres from Cape Thompson and Cape Lisburne shared a common wintering area in the southeastern Bering Sea in 1995, and birds from Cape Lisburne returned to the same area in the winter of 1996. We conclude that differences in foraging conditions during summer rather than differential mortality rates in winter account for contrasting population trends previously documented in those two colonies.

Alaska↗
USGS2000

Tracking the spring migration of a bar-headed goose ( Anser indicus ) across the Himalaya with satellite telemetry

Soil-food-chain-pesticide wildlife relationships were investigated to learn the concentration of pesticide residues present in soils, macro-invertebrates, vertebrates, and seeds as a result of annual applications of aldrin at recommended rates for pest control. Two central Missouri cornfields treated witb aldrin at 1 lb/acre, for 16 and 15 of the past 17 years, were selected for study during 1965-67. Primary samples collected for residue analyses included soils, earthworms (Lumbricidae), crickets (GryIlidae), and two kinds of ground beetles (Carabidae) obtained during early April, June, August, and October. Vertebrates and plant seeds collected during 1967 included white-footed mice (Peromyscus maniculatus), toads (Bufo americanus), snakes (Thamnophis sirtalis and Pituophis sayi), corn (Zea Mays), foxtail (Setaria Faberii), and annual sunflower (Helianthus annuus). Pesticide residues consisted primarily of dieldrin, the degradation product of aldrin. Combined aldrin and dieldrin residues, as two field all-season averages, wet weight basis, were: soils, 0.31 ppm; earthworms, 1.49 ppm; crickets, 0.23 ppm; Harpalus ground beetles, 1.10 ppm; Poecilus ground beetles, 9.67 ppm; white-footed mice, 0.98 ppm; toads, 3.53 ppm; garter snakes, 12.35 ppm; and corn, foxtail, and sunflower seeds less than 0.02 ppm each. Unusually high average residues (37.48 ppm) in Poecilus beetles during June, 1967, were attributed to abnormally high soil moisture and predacious feeding habits of these insects.

Global Environmental Research↗
USGS2000

Documenting trans-Himalayan migration through satellite telemetry: A report on capture, deployment, and tracking of bar-headed goose (Anser indicus)

Animal movement and migration studies have made significant progress with the use of telemetry. Conventional radio telemetry has been used in numerous studies in different regions. However, the use of this technology is restricted to species with limited range of movement. Applying this tool for long distance migrants is usually unsatisfactory. Other challenges such as hilly terrain or dense vegetation, where getting signals and following animals often become major constraints. These problems and the need to track long distance migrants, particularly birds, led to the development of other technologies with greater spatial coverage, accuracy and ease of tracking. Satellite telemetry technology has overcome many of these problems and has become a very useful tool. There is a greater recognition of the use and benefits of this technology among biologists, managers, and various conservation organizations. Satellite tracking technology has been used extensively in the Western Hemisphere. However until recently, in the Indian sub-continent the use of this technology was limited to one study in 1994 when three Eurasian cranes ( Grus grus ) were fitted with Platform Terminal Transmitter (PTTs) in Keoladco national Park, Bharatpur and tracked to their Siberian breeding grounds (Higuchi et al ., 1994). It took almost six more years for the next international collaborative project to emerge within India. This project, started in winter 1998-99, was the first long-term project using satellite tracking in India (Higuchi et al. , 1999). Other than these two studies, no effort has been made previously to demonstrate the use of this technology and its application in the Indian subcontinent.

Report↗
USGS2000

Performance of implantable satellite transmitters in diving seabirds

We report on the first deployment of satellite transmitters in large alcids. In 1995 and 1996, we surgically implanted 51 transmitters in Common and Thick-billed murres ( Uria aalge and U. lomvia ) and Tufted Puffins ( Fratercula cirrhata ) at three colonies in Alaska. These devices furnished more than 2,900 locations over succeeding months (eight months maximum transmitter life), some 30-40% of which had calculated errors of <1,000 m. We considered other data to be reliable if locations were repetitive within a short period of time. As measures of data collection efficiency, we calculated location indices (number of locations per hour of transmission) of 0.44 during the breeding season and 0.35 overall. Those values compared favorably with satellite transmitters previously deployed on large mammals at similar latitudes. Transmitters did not last as long as expected because lithium batteries tended to self-discharge when kept at the high internal temperature of a bird. Most importantly, we encountered high mortality of instrumented birds, especially in the interval from 11-20 days after release. Our results suggest that radio transmission itself somehow impaired normal feeding behavior or otherwise compromised the birds' health. Those two problems (battery life and bird mortality) will need to be solved before implantable devices can be applied effectively to the same or similar species in the future.

Alaska↗
USGS2000

Alagnak watershed rainbow trout seasonal movement

Adult rainbow trout were radio-tagged in two locations in the Alagnak River drainage in 1997 and 1998 and radio-tracked until March 1999. The telemetry data indicate the two different sample groups exhibited independent movements with little geographic overlap. However, some tagged fish from each sample group migrated downstream to the same general area during the spawning season. Rainbow trout within each sample group may have evolved the observed seasonal movement patterns to optimize food availability during the summer and thermal refugia in the winter.

Alaska↗
USGS1999

Comparative analysis of multisensor satellite monitoring of Arctic sea-ice

This report represents comparative analysis of nearly coincident Russian OKEAN-01 polar orbiting satellite data, Special Sensor Microwave Imager (SSM/I) and Advanced Very High Resolution Radiometer (AVHRR) imagery. OKEAN-01 ice concentration algorithms utilize active and passive microwave measurements and a linear mixture model for measured values of the brightness temperature and the radar backscatter. SSM/I and AVHRR ice concentrations were computed with NASA Team algorithm and visible and thermal-infrared wavelength AVHRR data, accordingly

Book↗
USGS1999

At-sea distribution of Spectacled Eiders: A 120-year-old mystery resolved

The at-sea distribution of the threatened Spectacled Eider ( Somateria fischeri ) has remained largely undocumented. We identified migration corridors, staging and molting areas, and wintering areas of adult Spectacled Eiders using implanted satellite-transmitters in birds from each of the three extant breeding grounds (North Slope and Yukon-Kuskokwim Delta in Alaska and arctic Russia). Based on transmitter locations, we conducted aerial surveys to provide visual confirmation of eider flocks and to estimate numbers of birds. We identified two principal molting and staging areas off coastal Alaska (Ledyard Bay and eastern Norton Sound) and two off coastal Russia (Mechigmenskiy Bay on the eastern Chukotka Peninsula, and the area between the Indigirka and Kolyma deltas in the Republic of Sakha). We estimated that >10,000 birds molt and stage in monospecific flocks at Mechigmenskiy and Ledyard bays, and several thousand molt and stage in eastern Norton Sound. We further identified eastern Norton Sound as the principal molting and staging area for females nesting on the Yukon-Kuskokwim Delta, and Ledyard Bay and Mechigmenskiy Bay as the principal molting and staging areas for females nesting on the North Slope. Males marked at all three breeding grounds molt and stage in Mechigmenskiy Bay, Ledyard Bay, and the Indigirka-Kolyma delta region. Males from the Yukon-Kuskokwim Delta molt and stage mainly at Mechigmenskiy Bay. Equal numbers of males from the North Slope molt and stage at all three areas, and most males from arctic Russia molt and stage at the Indigirka-Kolyma delta region. Postbreeding migration corridors were offshore in the Bering, Chukchi, and Beaufort seas. In winter, eiders were in the Bering Sea south of St. Lawrence Island. Our estimates from surveys in late winter and early spring suggest that at least 333,000 birds winter in single-species flocks in the pack ice in the Bering Sea.

Alaska↗
USGS1998

Satellite telemetry: A new tool for wildlife research and management

The U.S. Fish and Wildlife Service and the Alaska Department of Fish and Game have cooperated since 1984 to develop and evaluate satellite telemetry as a means of overcoming the high costs and logistical problems of conventional VHF (very high frequency) radiotelemetry systems. Detailed locational and behavioral data on caribou ( Rangifer tarandus ), polar bears ( Ursus maritimus ), and other large mammals in Alaska have been obtained using the Argos Data Collection and Location System (DCLS). The Argos system, a cooperative project of the Centre National d'Études Spatiales of France, the National Oceanic and Atmospheric Administration, and the National Aeronautics and Space Administration, is designed to acquire environmental data on a routine basis from anywhere on earth. Transmitters weighing 1.6-2.0 kg and functioning approximately 12-18 months operated on a frequency of 401.650 MHz. Signals from the transmitters were received by Argos DCLS instruments aboard two Tiros-N weather satellites in sun-synchronous, nearpolar orbits. Data from the satellites were received at tracking stations, transferred to processing centers in Maryland and France, and made available to users via computer tape, printouts, or telephone links. During 1985 and 1986, more than 25,000 locations and an additional 28,000 sets of sensor data (transmitter temperature and short-term and long-term indices of animal activity) were acquired for caribou and polar bears. Locations were calculated from the Doppler shift in the transmitted signal as the satellite approached and then moved away from the transmitter. The mean locational error for transmitters at known locations (n - 1,265) was 829 m; 90% of the calculated locations were within 1,700 m of the true location. Caribou transmitters provided a mean of 3.1 (+5.0. SD) locations per day during 6h of daily operation, and polar bear transmitters provided 1.7 (+6.9SD) locations during 12h of operation every third day. During the first 6 months of operation, the UHF (ultra-high frequency) signal failed on three of 32 caribou transmitters and 10 of 36 polar bear transmitters. A geographic information system (GIS) incorporating other databases (e.g., land cover, elevation, slope, aspect, hydrology, ice distribution) was used to analyze and display detailed locational and behavioral data collected via satellite. Examples of GIS applications to research projects using satellite telemetry and examples of detailed movement patterns of caribou and polar bears are presented. This report includes documentation for computer software packages for processing Argos data and presents developments, as of March 1987, in transmitter design, data retrieval using a local user terminal, computer software, and sensor development and calibration.

Resource Publication↗
USGS1997

Distribution and stability of eelgrass beds at Izembek Lagoon, Alaska

Spatial change in eelgrass meadows, Zostera marina L., was assessed between 1978 and 1987 and between 1987 and 1995 at Izembek Lagoon, Alaska. Change in total extent was evaluated through a map to map comparison of data interpreted from a 1978 Landsat multi-spectral scanner image and 1987 black and white aerial photographs. A ground survey in 1995 was used to assess spatial change from 1987. Eelgrass beds were the predominant vegetation type in the lagoon, comprising 44-47% (15000-16000 ha) of the total area in 1978 and 1987. Izembek Lagoon contains the largest bed of seagrass along the Pacific Coast of North America and largest known single stand of eelgrass in the world. There was a high degree of overlap in the spatial distribution of eelgrass among years of change detection. The overall net change was a 6% gain between, 1978 and 1987 and a <1% gain between 1987 and 1995. The lack of significant change in eelgrass cover suggests that eelgrass meadows in Izembek Lagoon have been stable during the 17-year period of our study.

Alaska↗
USGS1996

Assessing variability and trends in Arctic sea ice distribution using satellite data

Trends in the annual minimum, minimum monthly-mean, and the sea ice extent at the end of August were investigated for the Barents and western Kara Seas and adjacent parts of the Arctic Ocean during 1966 to 1994 using data from Russian ice maps (1974-1994), Kosmos-Okean and ALMAZ SAR satellite series (1984-1994), and published literature. Four definitions of sea ice extent were examined based on thresholds of ice concentration: >90%, >70%, >40% and >10% (E1, E2, E3, and E4, respectively). Root-mean-square differences between sea ice maps and satellite-image sea ice classifications for coincident areas were subjected to Monte-Carlo analyses to construct confidence intervals for the 20-year ice-map trends. With probability p=0.8, the average 20-year change in the minimum monthly-mean sea ice extent (followed in brackets by the average change in the absolute annual minimum ice extent) was between 30-60% [19-71%], 29-61% [15-67%], 31-63%[18-69%] and 18-48% [7-55%] in the Barents sea; (-24)-(-4)% [(-25)-(12)%], (-27)-(-9)% [(-34)-(-4)%], (-32)-(-15)% [(-39)-(-9)%] and (-33)-(-15)%[(-38)-(-8)%] in the western Kara sea; and (-3)-19% [(-8)-29%], (-4)-18% [(-11)-26%,] (-6)-16% [(-11)(-24)%] and (-7)-15% [(-12)-24%] in the combined Barents and Kara Seas, for sea ice concentration E1-E4, respectively. Including published data from 1966-1983, the trend in minimum monthly-mean sea ice extent for the combined 30-year period showed an average increasing of 11.8% in the Barents Sea and of 47.4% reduction in the western Kara Sea; sea ice extent at the end of August showed an average reduction of 4.7% in the Barents Sea.

Conference Paper↗
USGS1995

Use of implanted satellite transmitters to locate Spectacled Eiders at-sea

Population estimates of Spectacled Eiders ( Somateria fischeri ) on the Yukon-Kuskokwim Delta (YKD), Alaska, suggest that by 1992 the number of birds on this major nesting area had declined to 1,721 pairs, 4% of that estimated in the 1970s (Stehn st al 1993). Consequently, Spectacled Eiders were listed as threatened under the Endangered Species Act. As nesting habitats for this species are believed to have changed little over the past 100 years, hypotheses concerning the cause of this decline include factors away from nesting areas. The non-nesting distribution of this eider is unknown, but birds are believed to molt and winter in the Bering and Chukchi seas (Dau and Kistchinski 1977). Systematic aerial surveys to locate areas where birds concentrate are expensive because of the vast area to be surveyed and dangerous because of restricted daylight and extreme weather conditions. Surveys from ships along the ice margin in the Bering Sea failed to locate concentrations of birds (Irving et al 1968, Everett et al 1989). We initiated a study to determine if at-sea areas used by Spectacled Eiders could be identified using satellite telemetry.

Alaska↗
USGS1990

Seasonal movements of adult female polar bears in the Bering and Chukchi seas

Ten adult female polar bears ( Ursus maritimus ) were fitted with satellite telemetry collars during March 1986 in the Kotzebue Sound area of the Chukchi Sea. During March-April 1987, 2 of these bears were refitted with satellite telemetry collars and an additional 10 adult females were collared in the northern Bering and eastern Chukchi seas. Data for 1,560 point locations recorded through May 1988 indicated that female polar bears in the Bering and Chukchi seas were resident in western Alaskan waters from November through March, then moved northward with the receding pack ice during April and May. They remained in the northern and northwestern Chukchi Sea during June through September, often adjacent to the Soviet coastline. Satellite telemetry data indicated that 4 females marked in Alaskan waters of the Chukchi Sea apparently denned in the vicinity of Wrangel Island during winter 1987/1988. Denning in American territory of bears marked in the Chukchi and Bering seas has not been documented using satellite telemetry data. Some polar bears moved from the Chukchi Sea into the western Beaufort Sea during summer and fall, then returned to the Chukchi and Bering seas the following winter. Movements of bears from the Chukchi Sea into the central or eastern Beaufort Sea were not documented through spring 1988. These data document that polar bears occuring in the Bering and Chukchi seas are shared internationally between the United States and the Soviet Union.

Alaska↗
USGS1990

Procedures and rationale for marking sea otters captured and treated during the T/V Exxon Valdez oil spill

Four methods were used for marking sea otters ( Enhydra lutris ) captured and treated during the response to the T/V Exxon Valdez oil spill. Colored and numbered flipper tags were placed on each sea otter that was brought to the otter treatment centers. These tags allowed individual recognition and permitted the tracking of individuals through the treatment and holding processes. Recovery of tagged carcasses may provide a crude measure of the fates of rehabilitated otters. Seven sea otters were instrumented with radio transmitters attached to flipper tags as part of a pilot release program. The results of that study were inconclusive. Forty-five sea otters were implanted with radio transmitters as part of a study to assess the fate of rehabilitated sea otters. Specific objectives of the study include estimating survived rates and monitoring the reproductive success of the sample of rehabilitated sea otters and comparing the results with similar variables in a control population. Transponder chips were injected in the perianal region of all but seven of the instrumented sea otters, and all were tagged with red flipper tags. The advantages and disadvantages of each type of tag are discussed.

Alaska↗
USGS1990

Tracking wildlife by satellite: Current systems and performance

Since 1984, the U.S. Fish and Wildlife Service has used the Argos Data Collection and Location System (DCLS) and Tiros-N series satellites to monitor movements and activities of 10 species of large mammals in Alaska and the Rocky Mountain region. Reliability of the entire system was generally high. Data were received from instrumented caribou ( Rangifer tarandus ) during 91% of 318 possible transmitter-months. Transmitters failed prematurely on 5 of 45 caribou, 2 of 6 muskoxen ( Ovibos moschatus ), and 1 of 2 gray wolves ( Canis lupus ). Failure rates were considerably higher for polar ( Ursus maritimus ) and brown ( U. arctos ) bears than for caribou ( Rangifer tarandus ). Efficiency of gathering both locational and sensor data was related to both latitude and topography. Mean error of locations was estimated to be 954 m (median = 543 m) for transmitters on captive animals; 90% of locations were <1,732 m from the true location. Argos's new location class zero processing provided many more locations than normal processing, but mean location error was much higher than locations estimated normally. Locations were biased when animals were at elevations other than those used in Argos's calculations. Long-term and short-term indices of animal activity were developed and evaluated. For several species, the long-term index was correlated with movement patterns and the short-term index was calibrated to specific activity categories (e.g., lying, feeding, walking). Data processing and sampling considerations were evaluated. Algorithms for choosing the most reliable among a series of reported locations were investigated. Applications of satellite telemetry data and problems with lack of independence among locations are discussed.

Fish and Wildlife Technical Report↗