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At least 1,675 records · Page 93Linked to original sources
USGS2006

Radio telemetry for black-footed ferret research and monitoring

By 1973, radio telemetry was regarded as an important potential tool for studying the elusive, nocturnal, and semifossorial black-footed ferret (Mustela nigripes), but fears of using invasive techniques on this highly endangered mammal caused delays. We began radio collaring ferrets in 1981. Use of radio telemetry on ferrets proved to be both challenging and rewarding. We document two decades of development and use that led to the present radio-tagging techniques and methods for radio tracking. The 7-g radio collar commonly used after 1992 was smaller and lighter, relative to mass and size of subjects, than collars used in studies of other Mustela. Other important developments were a Teflon® coating to shed mud, a highly flexible stainless steel cable for whip antennas, and a nondurable wool collar. Although collar-caused neck abrasions have continued to occur sporadically, a retrospective assessment of minimum survival rates for 724 reintroduced ferrets (392 radio tagged), using data from spotlight surveys, failed to detect negative effects of radio-collars. In a South Dakota study, ferrets that were found to have hair loss or neck abrasions when collars were removed did not exhibit movements significantly different from those of radio-tagged ferrets with no evidence of neck problems. Prototype transmitters designed for surgical implantation had insufficient power output for effective use on ferrets. Early attempts at tracking radio-tagged ferrets by following the signal on foot quickly gave way to following movements by triangulation, which does not disturb the subjects. The most effective tracking stations were camper trailers fitted with rotatable, 11-element, dual-beam Yagi antennas on 6-m masts. We used radio telemetry to produce 83,275 lines of data (44,191 indications of status and 39,084 positional fixes via triangulation) for 340 radio-collared ferrets during the reintroduction program. Tracking by hand and from aircraft augmented triangulation, allowing us to locate animals that dispersed long distances and enabling us to determine causes of mortality. Justifying further use of radio telemetry on black-footed ferrets requires careful consideration of costs and benefits.

Conference Paper↗
USGS2008

Preliminary review of adaptation options for climate-sensitive ecosystems and resources. A report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research

Climate variables are key determinants of geographic distributions and biophysical characteristics of ecosystems, communities, and species. Climate change is therefore affecting many species attributes, ecological interactions, and ecosystem processes. Because changes in the climate system will continue into the future regardless of emissions mitigation, strategies for protecting climate-sensitive ecosystems through management will be increasingly important. While there will always be uncertainties associated with the future path of climate change, the response of ecosystems to climate impacts, and the effects of management, it is both possible and essential for adaptation to proceed using the best available science. This report provides a preliminary review of adaptation options for climate-sensitive ecosystems and resources in the United States. The term “adaptation” in this document refers to adjustments in human social systems (e.g., management) in response to climate stimuli and their effects. Since management always occurs in the context of desired ecosystem conditions or natural resource management goals, it is instructive to examine particular goals and processes used by different organizations to fulfill their objectives. Such an examination allows for discussion of specific adaptation options as well as potential barriers and opportunities for implementation. Using this approach, this report presents a series of chapters on the following selected management systems: National Forests, National Parks, National Wildlife Refuges, Wild and Scenic Rivers, National Estuaries, and Marine Protected Areas. For these chapters, the authors draw on the literature, their own expert opinion, and expert workshops composed of resource management scientists and representatives of managing agencies. The information drawn from across these chapters is then analyzed to develop the key synthetic messages presented below.

Synthesis and Assessment Product↗
USGS1991

Agricultural research to improve water quality

ime courses for ingest~on, retention and release via feces of microbial food was investigated using 2 b~valves w~th d~fferent feeding strategies, Potamocorbula amurensis and Macoma balthica. The results showed 2 pathways for the uptake of food material in these clams. The first is represented by an initlal label pulse in the feces. The second pathway operates over longer time periods. Inert "Cr-labeled beads were used to determine time frames for these pathways. The first pathway, involving extracellular digestion and intestinal uptake, is relatively inefficient In the digestion of bacter~al cells by P amurensis but more efficient in M. balthica. The second pathway, involving intracellular digestion withln the digestive gland of both clams, was highly efficient in absorb~ng bacterial carbon, and was responsible for most chromium uptake. Differences in the overall retention of microbial "Cr and I4C relate not to gut-passage times but to the processing and release strategies of the food material by these 2 clams.

Journal of Soil and Water Conservation↗
USGS2017

Fisheries research and monitoring activities of the Lake Erie Biological Station, 2016

We conducted a biomass-based assessment of the Lake Erie Western Basin fish community using data collected from 2013-2016 Western Basin (spring and autumn) bottom trawl surveys. Biomass of total catch per hectare has decreased 75 percent since 2013. Declines were observed across all functional groups, but most notable was the decline of Emerald Shiner, which decreased from 25.3 kg/ha in spring 2013 to <0.01 kg/ha by autumn 2013. The four primary predator species – Walleye, Yellow Perch, White Perch, and White Bass – all decreased from 2013 to 2015. In 2016, White Bass and Yellow Perch (all lifestages combined) continued to decline, while Walleye and White Perch (all ages combined) increased slightly from 5.6 kg/ha and 3.4 kg/ha to 9.0 kg/ha and 5.0 kg/ha, respectively (autumn catches). Despite decreasing trends in biomass, there was little change in biodiversity. Declines in forage biomass, i.e. Emerald Shiner and age-0 White Perch, resulted in an increased mean trophic level of catches. Forage fish to piscivore ratios reflected marked shifts in species composition toward greater forage in 2014 and 2016.

Lake Erie↗
USGS1985

Research on Alaskan polar bears in 1979 and 1980

In 1979 the U.S. Fish and Wildlife Service continued its program of mark and recapture. From 31 March to 4 May field crews working at Point Barrow, Alaska, captured and marked a total of 15 polar bears (Table I). The small number was due to very poor ice conditions off the coast of Alaska, making tracking and capturing difficult. Four of the bears were recaptures from previous years. In addition, as part of a multi-national program (Canada, U.S., Norway) satellite transmitters were attached to 3 adult female polar bears in the hopes of tracking them to their dens the following winter. However, due to mechanical and operational difficulties, very little information was acquired in the Alaskan sector of the project.

Alaska↗