American Falls Reservoir Research Articles

Mastodon mitochondrial genomes from American falls, Idaho

Palaeogenetics offers a powerful method to examine the evolutionary relationships between and within taxonomic groups. With sufficient data these analyses can be extended to provide information about the palaeodemography of extinct species. Recent mitochondrial genomes from North American Mammut have highlighted the roles glacial/interglacial cycles had on their range dynamics, but were geographically limited to a subset of American mastodon populations. Here we expand upon previous mastodon ancient DNA research with two new mitochondrial genomes from the American Falls Reservoir in Idaho. Our phylogenetic analyses place mastodons from this region as close relatives of other interglacial mastodons from eastern Beringia and may represent a southward dispersal in response to glacial advance. We attempt to contextualize our findings within the currently known distribution of American and Pacific mastodons, and suggest that a much more comprehensive examination of morphological variation within Mammut is likely required.

Isolation, Migration, and Local Recruitment Drive Persistence of Cutthroat Trout in Tributaries near American Falls Reservoir

AbstractWe analyzed 67 SNPs to describe the genetics of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri in seven tributaries near American Falls Reservoir, Idaho. We detected Yellowstone Cutthroat Trout in all but one site despite significant historical stocking of Rainbow Trout O. mykiss. Three of four relatively low‐elevation sites near the reservoir contained Yellowstone Cutthroat Trout in sympatry with early‐generation hybrids and Rainbow Trout yet contained no physical barriers to admixture. A posteriori assignment tests suggested that migrants from a nearby headwater population in Ross Fork Creek and possibly recruitment by local‐origin Yellowstone Cutthroat Trout with fluvial or adfluvial life histories drive persistence in these sites. In contrast, hybridization was rare or absent in headwater populations and was associated with complete or apparent physical isolation. We also compared genetic diversity of our samples with Yellowstone basin Yellowstone Cutthroat Trout and Bear River Bonneville Cutthroat Trout O. c. utah to examine possible historical gene flow resulting from hydrogeological connections during the Pleistocene. Multivariate analysis showed that most genetic variation among individuals was explained by divergence of Yellowstone basin Yellowstone Cutthroat Trout from our samples and Bear River Bonneville Cutthroat Trout, which supports recent mtDNA studies and a possible change in taxonomic nomenclature. Our results indicate that, due to relative isolation and downstream emigration, headwater populations are critical to the persistence of Yellowstone Cutthroat Trout and thus loss of such populations would likely threaten the subspecies throughout the region. Management actions to reduce threats from established, nonnative Rainbow Trout populations will likely have to be multifaceted and may include a combination of targeted removal of Rainbow Trout and hybrids and the use of physical barriers to prevent further dispersal.Received April 19, 2015; accepted February 7, 2016 Published online May 31, 2016

COLLECTING HISTORY OF VERTEBRATE FOSSILS AT AMERICAN FALLS, IDAHO: A RESERVOIR OF DATA TO INFORM LAND-USE POLICY

ABSTRACT Hundreds of reservoirs in the western United States are managed on public lands and often contain significant paleontological resources. GIS (Geographic Information Systems) analysis of fossil collecting can help identify factors that affect fossil conservation in these multiuse facilities. Eighty years of collection history by Idaho Museum of Natural History personnel of Pleistocene vertebrates at the American Falls Reservoir, Idaho, United States, show that collections by the museum do not correlate with points of reservoir access or to coastal slope, and suggest that instead, collection history most likely tracks actual fossil productivity. Land management practice to install riprap rock barriers to mitigate coastal erosion is effective at reducing exposure of fossils at the decadal scale, thereby meeting the avoidance criterion of fossil preservation which seeks to limit exhumation of fossil resources. However, the first five years following riprap installation show a significant increase in ...

Using a Distribution and Conservation Status Weighted Hotspot Approach to Identify Areas in Need of Conservation Action to Benefit Idaho Bird Species

Abstract Identification of biodiversity hotspots (hereafter, hotspots) has become a common strategy to delineate important areas for wildlife conservation. However, the use of hotspots has not often incorporated important habitat types, ecosystem services, anthropogenic activity, or consistency in identifying important conservation areas. The purpose of this study was to identify hotspots to improve avian conservation efforts for Species of Greatest Conservation Need (SGCN) in the state of Idaho, United States. We evaluated multiple approaches to define hotspots and used a unique approach based on weighting species by their distribution size and conservation status to identify hotspot areas. All hotspot approaches identified bodies of water (Bear Lake, Grays Lake, and American Falls Reservoir) as important hotspots for Idaho avian SGCN, but we found that the weighted approach produced more congruent hotspot areas when compared to other hotspot approaches. To incorporate anthropogenic activity into hotspot...

Migrant Shorebird Habitat Use and the Influence of Water Level at American Falls Reservoir, Idaho

AssTRAcr-Shorebirds migrating at American Falls Reservoir, Snake River, Idaho, were counted in fall from 1986 to 1988 to determine their habitat use and the influence of water level changes. Reservoir water levels changed within and between seasons, sometimes changing the habitat type at specific sites. Shorebirds concentrated on mudflats, whereas sandy, clay, and boulder beaches, and bedrock supported very low numbers of individuals and species. Shorebirds were excluded from some important mudflats in early migration in 1986 because of flooding by high water, and densities drastically dropped after a rise in water flooded some mudflats later in the season. Shorebird numbers were correlated with water drawdown in 1986. There were equal or higher numbers of shorebirds at the large mudflat site in 1987 and 1988 when water drawdown caused the shoreline to recede 15,000 to 20,000 m versus 1986 when the shoreline receded 3200 m. This study shows that man-made reservoirs can provide important staging areas for migrating shorebirds. Mudflats should be made available on reservoirs in the intermountain western United States from late June through October.

First Record of a Black-Legged Kittiwake in Idaho

The Black-legged Kittiwake (Rissa tridactyla) is a common oceanic gull that winters off the Pacific coast from British Columbia south to northwestern Baja, California (A.O.U. Check-list 1957). While there have been several inland reports of Black-legged Kittiwakes in various western states (Haywood et al. 1976, Weber and Larrison 1977, and others), to our knowledge this species has never before been reported in Idaho. The purpose of this note is to document the first record of this species in Idaho and to review past records of the kittiwake in adjacent states. The carcass of a juvenile male Black-legged Kittiwake was found by the authors on 13 February 1980, approximately 5 km southeast of Howe, Butte Co., Idaho. The nearest large body of water is American Falls Reservoir, located on the Snake River, 85 km to the southeast. This bird appeared to have been dead less than 24 h. A large wound on the dorsal portion of the body, just behind the neck, indicated that the bird may have been killed by a raptor. The carcass weighed 277.5 g and contained no deposits of body fat. Most of the inland sightings of Black-legged Kittiwakes in the northwestern United States have been made in the last eight years (Table 1). It is unclear whether this recent increase in sightings is the result of greater effort by field biologists, or if it results from a pioneering tendency of the kittiwake due to an increase in the number of reservoirs along major northwestern rivers. Juvenile gulls of many species wander great distances in the late summer and fall (Pettingill 1970, Parsons and Duncan 1978). Since at least one of the records was for an adult and most of the sightings occurred during the winter and early spring, this does not immediately offer a satisfactory explanation for the majority of inland kittiwake records. Further, the sightings ofkittiwakes do not follow the same pattern as those of the Ancient Murrelet (Synthliboramphus antiquu ; Munger 1965); Munger indicated that murrelets wander inland primarily during October and November, and their movements are associated directly or indirectly with adverse weather over the Pacific coast. However, we found that at least one and usually a ser es of low pressure systems had moved inland across the Pacific Northwest within a twoto three-week period just before each inland kittiwake sighting (U.S. Dep. of Commerce) except for the 1898 sighting, for which we have no data. We suggest that inland movements by the Black-legged Kittiwake are often the result of winter storms moving inland from the Pacific coast.

Pesticide and mercury levels in pelicans in Idaho.

Levels of organochlorine pesticides and mercury residues found in the White Pelican, Pelicanus erythrorhynchos, in southern Idaho are reported. Twelve white pelicans were collected and autopsied to obtain specimens for mercury analysis. They were collected along the Snake River about three miles downstream from the American Falls Reservoir. An additional bird was tested for organochlorine pesticides. This bird was found dead in the Lake Lowell region of Idaho at about the same time the other birds were collected. Analysis was made on each organ tissue separately and the results reported on a wet weight basis. The highest levels of mercury were found in the liver tissues, the highest mercury level being 32.80 ppm and the lowest level in the particular tissue 2.33 ppm. The organochlorine residues were so high in the single bird studied for these pesticides as to possibly account for its death. (MU)

Reservoir Topography by Shoreline Plotting

Irrigation development in the 35,000 sq mile Upper Snake River Basin, above Bliss, Idaho, requires coordinated use of uncommitted ground and surface water. To use the surface water, new storage is needed; enlargement of American Falls Reservoir is a possibility. To appraise enlargement, the present (1963) capacity of the reservoir has to be known. Reservoir remapping was based on plotting the shoreline, the contact between water-line and ground-line, at selected reservoir water-surface elevations. A triangulation network of shore points extending into dewatered zones provided horizontal control. Multiple flights for aerial photography of the shoreline were used in obtaining vertical ground control. Where banks were steep, successive flights gave infinite image point elevations for vertical control, allowing conventional stereoplotting.

Skull of Fossil Camelid from American Falls Lake Bed Area of Idaho

Much camel material is present in the Idaho State College museum collection of vertebrate fossils. Since 1939 this material has been collected from various stratigraphic horizons, chiefly within a forty-mile radius of Pocatello. Included in the area of research are the Pleistocene American Falls lake beds as well as the alluvial deposits overlying these beds. Part of our camelid collection came from the gravel pit near American Falls, worked by Dr. J. W. Gidley and Dr. C. L. Gazin (1935). More recently we have opened quarries just above the old town site of American Falls in an area stripped during World War II by the Bureau of Reclamation. From the recent excavations we have collected many jaws, teeth and skeletal parts of camels, ranging in age from juvenile to aged. The camelid skull, I.S.C. No. 1500, with which the present paper deals, is from a lower stratigraphic horizon than that of the American Falls gravel pits. It does not seem to be either Camelops minidokae or Camelops hesternus , the species that previous workers, Hay (1927) and Gazin (1935), have reported from southeastern Idaho. Savage (1951) discusses the status of the genus Camelops . He concludes that the species that should be given zoological usage are Camelops hesternus (Leidy), Camelops huerfanensis (Cragin), Camelops sulcatus (Cope) and Camelops minidokae (Hay). Skull No. 1500 seems to be in the larger size range mentioned by Dr. Savage, viz., the C. hesternus — C. huerfanensis group. The site where I found it in April, 1951, is about 621 yards up the beach of American Falls reservoir from a Bison latifrons skull (Hopkins, Plate I, 1951). Wave action had washed up the skull so that it lay 33 feet out from the base of the cliff with only the teeth and palate …