Source: UNIV OF CALIFORNIA (VET-MED) submitted to
ANZA BORREGO BIGHORN SHEEP POPULATION HEALTH STUDY
Sponsoring Institution
Cooperating Schools of Veterinary Medicine
Project Status
COMPLETE
Funding Source
STATE
Reporting Frequency
Annual
Accession No.
0177508
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Jun 1, 1994
Project End Date
Jun 30, 2004
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Project Director
Boyce, W. M.
Recipient Organization
UNIV OF CALIFORNIA (VET-MED)
(N/A)
DAVIS,CA 95616
Performing Department
PATHOLOGY, MICROBIOLOGY & IMMUNOLOGY
Non Technical Summary
(N/A)
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1350840106070%
1350840107030%
Knowledge Area
135 - Aquatic and Terrestrial Wildlife;

Subject Of Investigation
0840 - Fur-bearing animals;

Field Of Science
1060 - Biology (whole systems); 1070 - Ecology;
Goals / Objectives
The main objective of this study is to generate data-supported management recommendations that promote the long-term survival of viable peninsula sheep populations. The data to be collected under this agreement will be gathered by field monitoring of radio-collared bighorn sheep in the following areas in ABDSP: Santa Rosa Mountains, Coyote Canyon, San Ysidro Mountains, Vallecito Mountains, Carrizo Canyon.
Project Methods
1) The distribution and seasonal movements of bighorn in ABDSP will be identified by locating each radiocollared sheep on a monthly basis. This will allow us to identify home ranges1 movement corridors, and lambing areas. 2) Lamb production, survivorship, and recruitment will be determined by monthly observation of radiocollared ewes and their associated group members. 3) Dead animals will be located using mortality sensors in the radiocollars (or via reports from hikers and park personnel) and the cause of death determined to the extent possible (via scene investigation and necropsy). This will allow us to determine age specific mortality rates and identify the significance of different causes of mortality (disease, predation, etc.). 4) Population size for each of the 5 areas in ABDSP will be evaluated by mark and recapture techniques based on ground and aerial observations of marked and unmarked bighorn.

Progress 06/01/94 to 06/30/04

Outputs
During the project period, we monitored the bighorn sheep population in Anza-Borrego Desert State Park (ABDSP) with the aid of telemetry collars and onsite biologists. During October 8-19, 2001, 75 bighorn sheep from 8 areas within the park were captured by net gun, sampled, and fitted with telemetry collars. These animals' movements and any mortalities are being documented, and the information will be used to determine management policies that will hopefully make the recovery of this endangered species a success. This project was funded by the California Department of Parks and Recreation.

Impacts
Peninsular bighorn sheep are currently on the Federal Endangered Species List. Data on yearly survival, birth, recruitment, and mortality rates, as well as causes of mortality and morbidity, will provide a foundation for developing management recommendations to promote the long-term survival of these animals.

Publications

  • Guitierrez-Espeleta, G.A., S.T. Kalinowski, W.M. Boyce, and P.W. Hedrick. 2000. Genetic variation and population structure in desert bighorn sheep; implications for conservation. Conservation Genetics. 1:3-15
  • Gutierrez-Espeleta, G.A., P.W. Hedrick, S.T. Kalinowski, and W.M. Boyce. 2001. Is the decline of desert bighorn sheep from infectious disease the result of low MHC variation? Heredity. 86:439-451.
  • Ernest, H.B., E.S. Rubin, and W.M. Boyce. 2002. Fecal DNA analysis and risk assessment of mountain lion predation of bighorn sheep. Journal of Wildlife Management. 66:75-85. (in press)
  • Rubin, E.S., W.M. Boyce, and E.P. Caswell-Chen. 2002. Modelling demographic processes in an endangered population of bighorn sheep. Journal of Wildlife Management. 55:000-000. (in press)
  • Rubin, E.S., W.M. Boyce, C.J. Stermer, and S.G. Torres. 2002. Bighorn sheep habitat use and selection near an urban environment. Biological Conservation. (in press)


Progress 01/01/00 to 12/31/00

Outputs
We have continued to study the population biology and ecology of the bighorn sheep in Anza-Borrego Desert State Park (ABDSP). Some of the data collected in preceding years have been analyzed and the results published during this period.

Impacts
Peninsular bighorn sheep are currently on the Federal Endangered Species List. Data on yearly survival, birth, recruitment, and mortality rates, as well as causes of mortality and morbidity, will provide a foundation for developing management recommendations to promote the long-term survival of these animals.

Publications

  • Borjesson, D.L., Christopher, M.C., and Boyce, W.M. 2000. Biochemical and hematologic reference intervals for free-ranging desert bighorn sheep. J. Wildlife Dis. 36:294-300.
  • Chang, C., Chomel, B.B., Kasten, R.W., Heller, R., Kocan, K.M., Ueno, H., Yamamoto, K., Bleich, V.C., Pierce, B.M., Gonzales, B.J., Swift, P.K., Boyce, W.M., Yang, S.S., Boulouis, H., and Piemont, Y. 2000. Bartonella spp. isolated from wild and domestic ruminants in North America. Emerging Infectious Dis. 6: 306-311.
  • Guitierrez-Espeleta, G.A., Kalinowski, S.T., Boyce, W.M., and Hedrick, P.W. 2000. Genetic variation and population structure in desert bighorn sheep: implications for conservation. Cons. Genetics. 1: 3-15.
  • Hayes, C.L., Rubin, E.S., Jorgensen, M.C., Botta, R.A., and Boyce, W.M. 2000. Mountain lion predation on bighorn sheep in the Peninsular Ranges, California. J. Wildlife Management. 64(4): 954-959.
  • Rubin, E.S., Boyce, W.M., and Bleich, V.C. 2000. Reproductive strategies of desert bighorn sheep. J. Mammalogy. 81(3): 769-786.


Progress 01/01/99 to 12/31/99

Outputs
This project has continued with the monitoring of bighorn sheep in Anza Borrego Desert State Park (ABDSP). Some of the data collected in preceding years have been analyzed and the results published.

Impacts
The Peninsular Bighorn Sheep are currently on the Federal Endangered Species List. Data on yearly survival, birth, recruitment, and mortality rates, as well as causes of mortality and morbidity, will provide a foundation for developing management recommendations to promote the long-term survival of these animals.

Publications

  • Boyce, W.M., R.R. Ramey II, T.C. Rodwell, E.S. Rubin, and R.S. Singer. 1999. Population subdivision among desert bighorn sheep (Ovis canadensis) ewes revealed by mitochondrial DNA analysis. Molecular Ecology, 8:99-106.
  • Rubin, E.S., W.M. Boyce, M.C. Jorgensen, S.G. Torres, C.L. Hayes, C.S. O'Brien, and D.A. Jessup. 1998. Distribution and abundance of bighorn sheep in the Peninsular Ranges, California. Wildlife Society Bulletin, 26(3):539-551.


Progress 01/01/98 to 12/31/98

Outputs
The major goal of this continuing study is to generate data that could be used to develop management recommendations that promote the long-term survival of bighorn sheep in Anza Borrego Desert State Park and the Peninsular Ranges. All radiocollared sheep have been monitored at least once per month since being collared in 1992-1993. Incidents of lion predation on radiocollared sheep were more common during the cooler, wetter winter months of the year and did not occur at the same rate in every year. One objective of the study was to document the patterns of lamb recruitment (lamb production and lamb survival) in multiple ewe groups in the Peninsular Ranges and to test hypotheses regarding factors that potentially influence the reproductive success of the individual ewe and the ewe group. Our analysis indicates that lamb production is relatively high (mean = approximately 75%) when all ewe groups and years are combined. Annual per group lamb survival to 3 and 6 months fluctuated greatly among years and ewe groups (range 36-100% for 3-month survival and 9-80% for six-month survival). We found that the majority of lambs (approximately 75%) were born in March and April. This is a shorter lambing season than previously attributed to desert bighorn sheep. In addition, our data reveals that ewes are able to raise lambs to 6 months of age in consecutive years. We used data collected at waterhole counts during the past 26 years (1971-1996) as an index of abundance and examined this data with regression analysis to identify trends in the number of sheep observed. We found that a significant decline had occurred in Coyote Canyon during the past 26 years and that this decline was caused primarily by the cessation of bighorn sheep use of Cougar and Sheep Canyons. Carrizo Canyon, which was counted for a ten-year period (1973-1982), also exhibited a significant decline in bighorn sheep abundance during the years counted. We found; however, that bighorn sheep abundance has remained stable in the north and south San Ysidro Mountains, regions used by two separate ewe groups. These findings provide evidence that long-term declines have occurred in the Peninsular Ranges, but that some areas have supported stable ewe groups. This suggests that ewe groups are influenced by local factors.

Impacts
(N/A)

Publications

  • RUBIN, E.S., W.M. BOYCE, M. JORGENSEN S. TORRES, C. HAYES, C. OBRIEN, and D.A. JESSUP. 1998. The distribution and abundance of bighorn sheep in the Peninsular Ranges, California. Wildlife Society Bulletin. In press.