Geology topics

Research about Hart Mountain National Antelope Refuge

Source-linked reports with geographic coverage including Hart Mountain National Antelope Refuge.

4 recordsLinked to original sources

USGS2009

The adrenocortical response of greater sage grouse (Centrocercus urophasianus) to capture, ACTH injection, and confinement, as measured in fecal samples

Investigators of wildlife populations often utilize demographic indicators to understand the relationship between habitat characteristics and population viability. Assessments of corticosterone may enable earlier detection of populations at risk of decline because physiological adjustments to habitat disturbance occur before reproductive diminutions. Noninvasive methods to accomplish these assesments are important in species of concern, such as the greater sage grouse (GRSG). Therefore, we validated a radioimmunoassay that measures immunoreactive corticosterone metabolites (ICM) in fecal samples and used it to characterize the adrenocortical response of 15 GRSG exposed to capture, intravenous injection of 50 IU/kg adrenocorticotrophic hormone (ACTH) or saline, and 22 h of confinement. Those animals injected with ACTH exhibited a more sustained (P = 0.0139) and less variable (P = 0.0012) response than those injected with saline, indicating different levels of adrenocortical activity. We also found that potential field-collection protocols of fecal samples did not alter ICM concentrations: samples held at 4??C for up to 16 h contained similar levels of ICM as those frozen (-20??C) immediately. This study demonstrates a multiphasic adrenocortical response that varied with the level of stimulation and indicates that the assay used to measure this phenomenon is applicable for studies of wild GRSG. ?? 2009 by The University of Chicago. All rights reserved.

Oregon↗

USGS2000

Septicemic pasteurellosis in free-ranging neonatal pronghorn in Oregon

As part of a study to determine the cause(s) of population decline and low survival of pronghorn ( Antilocapra americana ) neonates on Hart Mountain National Antelope Refuge (HMNAR), Oregon (USA), 55 of 104 neonates captured during May 1996 and 1997 were necropsied (n = 28, 1996; n = 27, 1997) to determine cause of death. Necropsies were conducted on fawns that died during May, June, or July of each year. The objectives of this study were to report the occurrence and pathology of pasteurellosis in neonates and determine if the isolated strain of Pasteurella multocida was unique. Septicemic pasteurellosis, caused by P. multocida , was diagnosed as the cause of death for two neonates in May and June 1997. Necropsy findings included widely scattered petechial and ecchymotic hemorrhages found over a large portion of the subcutaneous tissue, meninges of the brain, epicardium, skeletal muscle, and serosal surface of the thorasic and abdominal cavities. Histological examination of lung tissues revealed diffuse congestion and edema and moderate to marked multifocal infiltrate of macrophages, neutrophils, and numerous bacteria within many terminal bronchioles and alveoli. Pasteurella multocida serotypes A:3,4, and B:1 were isolated from several tissues including lung, intestinal, thorasic fluid, and heart blood. Each B:1 isolate had DNA restriction endonuclease fingerprint profiles distinct from isolates previously characterized from domestic cattle, swan ( Olor spp.), moose ( Alces alces ), and pronghorn from Montana (USA). This is the first report of pasteurellosis in pronghorn from Oregon and the B:1 isolates appear to be unique in comparison to DNA fingerprint profiles from selected domestic and wild species.

Oregon↗

USGS1998

Health evaluation of pronghorns (Antilocapra americana) on Hart Mountain National Antelope Refuge in southeastern Oregon, 1996-1997.

One hundred four neonatal (fawns) and 40 adult female (does) pronghorn antelope (pronghorns) ( Antilocapra americana ) were captured on the Hart Mountain National Antelope Refuge (HMNAR) in Lake County, southeastern Oregon, between 13 May 1996 and 26 May 1997. Blood and fecal samples were taken for an investigation of low fawn survival that may be due to disease and/or poor nutrition. No abnormalities were found in hematological parameters of adult does (n = 40) or fawns (n = 44 to 67). In general, there were lower serum total proteins (TP) and Blood Urea Nitrogen (BUN) concentrations in this population than in other populations from Alberta, Canada; Idaho; and Baker City, Oregon. Mean BUN values in does were significantly lower (p < 0.001) in December than March. The duration of this apparently low protein content of the December diet may affect the weight of the newborn and consequent survivability if it should continue into late gestation (March-May). Serum copper (Cu) levels in does (range 0.39 to 0.74 ppm) were considered marginal when compared to domestic animals and some wild ungulates. Fawns had low but apparently normal Cu levels at birth and reached the does' marginal values in about three days. Whole blood and serum Selenium (Se) levels (<100 ng/ml) were considered to be marginal to low in most segments of the pronghorn population in this study. However, serum levels of vitamin E (range 1.98 - 3.27 pg/ml), as determined from the does captured in March, are apparently sufficient to offset any signs of deficiency due to low Se levels. No clinical signs of Cu or Se deficiency were observed. Does captured in December 1996 were tested for neutralizing antibodies to Brucella spp. (n = 20, neg.), Leptospira spp. (n = 20, neg.), bluetongue virus (n = 20, 35% pos.), epizootic hemorrhagic disease virus (n = 20, 30% pos.), respiratory syncytial virus (n = 18, neg.), parainfluenza virus type 3 (n = 18, 67% pos.), infectious bovine rhinotracheitis (n = 18, neg.), and bovine viral diarrhea (n = 18, neg.). Seventeen fawns (9F,8M), nine in 1996 and eight in 1997, survived until at least mid-July each year. Fifty-five of 87 dead fawns were necropsied. Predation by coyotes (Canis latrans) accounted for the majority of fawn mortality (62%), as determined by necropsy, during the two combined summer periods. Other causes of mortality for the combined years included predation by eagle (4%), dystocia (2%), septicemic pasteurellosis (5%), starvation/weak fawn syndrome

Oregon↗

USGS1967

Mineral appraisal of the Poker Jim Ridge and Fort Warner areas of the Hart Mountain National Antelope Refuge, Lake County, Oregon

The Poker Jim Ridge and Fort Warner areas, which are candidate areas for inclusion in the National Wilderness Preservation System, are in the Hart Mountain National Antelope Refuge in east-central Lake County, south-central Oregon. The two areas form part of an upraised and tilted fault block--a structural element that is typical of the northern part of the Great Basin province. Rocks in the two areas are principally volcanic in origin. They have been faulted, uplifted, and tilted eastward, the older rocks having been more strongly deformed than the younger ones.

Oregon↗