The Sierra Nevada bighorn sheep (Ovis canadensis sierrae) is subspecies of bighorn sheep unique to the Sierra Nevada mountains of California.[2] A 2016 genetics study confirmed significant divergence between the three subspecies of North America's bighorn sheep: Sierra Nevada bighorn sheep, Rocky Mountain bighorn sheep and desert bighorn sheep.[3] Sierra Nevada bighorn sheep were listed as a federally endangered subspecies in 2000.[4] As of 2016, over 600 Sierra bighorn remain in the wild.[5]
Sierra Nevada bighorn range in color from white to dark brown, with a white rump and dark tail.[6] There is some seasonal change in coloration due to the shedding of a thicker winter layer.[5] Specialized hooves with adhesive soles provide traction in steep rocky terrain.[6] Female bighorn (ewes) can weigh up to 70 kilograms (155 lb) and have shorter, narrow horns, while male bighorn (rams) can weigh as much as 100 kilograms (220 lb) and have massive, curving horns.[5] The horns of both rams and ewes are composed of a dense layer of keratin covering a core of bone.[5]
The average lifespan for Sierra Nevada bighorn males and females has been observed as 8 to 12 years.[4]
Behavior
Sierra Nevada bighorn sheep are gregarious, with group size and composition depending on gender and season. Spatial segregation by gender occurs outside of the mating season. Bighorn sheep ewes generally remain with the same band in which they were born. Males older than 2 years of age remain apart from females and younger males for most of the year. During the late fall and winter, the groups come together and concentrate in suitable winter habitat. During this time, males compete for dominance with behaviors like horn clashes. Breeding takes place in late fall, generally November and December. Lambing occurs between late April and early July on safe, precipitous, rocky slopes; most lambs in the Sierra Nevada are born in May and June. Ewes and lambs often occupy steep terrain that provides a diversity of exposures and slopes for escape cover.[4]
Habitat
Sierra bighorn are found in portions of the Sierra Nevada from Yosemite National Park to Olancha Peak. Habitat occurs from the eastern base of the range as low as 1,460 m (4,790 ft) to peaks above 4,300 m (14,100 ft). Sierra bighorn inhabit open areas where the land is rocky, sparsely vegetated, and characterized by steep slopes and canyons. Wehausen[7] provides a detailed description of Sierra bighorn habitat throughout their range. Bighorn prefer open ground with high visibility to better detect predators and allow enough time to reach steep, rocky areas (escape terrain). Forests and thick brush are usually avoided if possible.[4]
Most bighorn live at elevations from 3,000–4,300 m (10,000–14,000 ft) in subalpine and alpine areas during the summer. During winter, some bighorn occupy high-elevation, windswept ridges, while others migrate to lower elevations to avoid deep snow and to find forage.[4]
Diet
Herd at Wheeler Crest
Sierra bighorn are ruminant herbivores with four-chambered stomachs.[6] Bighorn are primarily grazers, consuming various grasses, forbs, and woody vegetation depending on season and location. Naturally occurring mineral licks provide necessary minerals for bone and muscle growth.[4]
Endangerment
Centuries of unregulated hunting, disease outbreaks, and mountain lion predation took a heavy toll on the Sierra bighorn population. However, disease played the largest role in the decline of the subspecies with domestic sheep transmitting virulent diseases, in particular pneumonia from Pasteurella, beginning in the 1870s.[8] By the 1970s about 250 animals remained, occupying only two small areas of their former vast range. Translocations by the California Department of Fish and Wildlife (CDFW) helped to reestablish bighorn herds in historic habitat, but in spite of these efforts the population hit a low of about 100 total individuals in 1995.[9] On January 3, 2000, Sierra bighorn were listed as a federally endangered subspecies.[4]
Species recovery
In 1999, CDFW was made the lead agency responsible for implementing Sierra bighorn recovery. A group of stakeholders drafted the Sierra Nevada Bighorn Sheep Recovery Plan, and CDFW formed the Sierra Nevada Bighorn Sheep Recovery Program to work toward the goals of the Recovery Plan.[10] Since then conditions have been particularly favorable for population growth, with the total number of individuals reaching about 250 by 2002[11] and about 600 in 2016.[5] The Recovery Program continues to monitor population growth, habitat use, and cause-specific mortality of Sierra bighorn, and to carry out augmentations and translocations in an effort to achieve recovery goals.[10]
^"Sierra Nevada Bighorn sheep (Ovis canadensis sierrae) species profile". Environmental Conservation Online System. United States Fish and Wildlife Service. March 3, 2010.
^Wehausen, J.D.; V.C. Bleich; R.R. Ramey II (2005). (PDF). California Fish and Game. 91 (3): 216–218. Archived from the original (PDF) on 2006-09-06. Retrieved 2006-07-16.
^Buchalski, Michael R.; Sacks, Benjamin N.; Gille, Daphne A.; Penedo, Maria Cecilia T.; Ernest, Holly B.; Morrison, Scott A.; Boyce, Walter M. (2016). "Phylogeographic and population genetic structure of bighorn sheep (Ovis canadensis) in North American deserts". Journal of Mammalogy. 97 (3): 823–838. doi:10.1093/jmammal/gyw011. PMC5993094. PMID 29899578.
^ abcdefg This article incorporates public domain material from Designation of Critical Habitat for the Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae) and Taxonomic Revision; Final Rule. Fish and Wildlife Service. (73 FR 45534).
^ abcde"Sierra Nevada Bighorn Sheep Facts". California Department of Fish and Wildlife. Retrieved 2018-05-05.
^ abc. Sierra Nevada Bighorn Sheep Foundation. Archived from the original on 2013-10-29. Retrieved 2013-10-23.
^Wehausen, J.D. (1980). Sierra Nevada bighorn sheep: history and population ecology (Ph.D. thesis). Univ. Michigan, Ann Arbor. pp. 18–25.
^Evaluation of Priorities and Costs in Species Recovery Plans: Sonoran Pronghorn, Louisiana Black Bear, and Sierra Nevada Bighorn Sheep(PDF) (Thesis). The Evergreen State College. April 2013. Retrieved 2016-03-26.
^"US Fish and Wildlife Service endangered species recovery plan for the Sierra Nevada Bighorn Sheep" (PDF). Retrieved 2005-06-13.
^ ab"Sierra Nevada Bighorn Sheep Recovery Program". California Department of Fish and Wildlife. Retrieved 2013-10-24.
^(PDF). Archived from the original (PDF) on 2006-09-28. Retrieved 2006-11-17.
^Boxall, Bettina (April 10, 2014). "Bighorn sheep get a helicopter ride to the Sierra west side". Los Angeles Times.
sierra, nevada, bighorn, sheep, ovis, canadensis, sierrae, subspecies, bighorn, sheep, unique, sierra, nevada, mountains, california, 2016, genetics, study, confirmed, significant, divergence, between, three, subspecies, north, america, bighorn, sheep, rocky, . The Sierra Nevada bighorn sheep Ovis canadensis sierrae is subspecies of bighorn sheep unique to the Sierra Nevada mountains of California 2 A 2016 genetics study confirmed significant divergence between the three subspecies of North America s bighorn sheep Sierra Nevada bighorn sheep Rocky Mountain bighorn sheep and desert bighorn sheep 3 Sierra Nevada bighorn sheep were listed as a federally endangered subspecies in 2000 4 As of 2016 over 600 Sierra bighorn remain in the wild 5 Sierra Nevada bighorn sheepEwes and lambs on Wheeler CrestConservation statusEndangered ESA 1 Scientific classificationKingdom AnimaliaPhylum ChordataClass MammaliaOrder ArtiodactylaFamily BovidaeSubfamily CaprinaeTribe CapriniGenus OvisSpecies O canadensisSubspecies O c sierraeTrinomial nameOvis canadensis sierrae Grinnell 1912 Contents 1 Physical characteristics 2 Behavior 3 Habitat 4 Diet 5 Endangerment 6 Species recovery 7 ReferencesPhysical characteristics Edit Ram and ewes Sierra Nevada bighorn range in color from white to dark brown with a white rump and dark tail 6 There is some seasonal change in coloration due to the shedding of a thicker winter layer 5 Specialized hooves with adhesive soles provide traction in steep rocky terrain 6 Female bighorn ewes can weigh up to 70 kilograms 155 lb and have shorter narrow horns while male bighorn rams can weigh as much as 100 kilograms 220 lb and have massive curving horns 5 The horns of both rams and ewes are composed of a dense layer of keratin covering a core of bone 5 The average lifespan for Sierra Nevada bighorn males and females has been observed as 8 to 12 years 4 Behavior EditSierra Nevada bighorn sheep are gregarious with group size and composition depending on gender and season Spatial segregation by gender occurs outside of the mating season Bighorn sheep ewes generally remain with the same band in which they were born Males older than 2 years of age remain apart from females and younger males for most of the year During the late fall and winter the groups come together and concentrate in suitable winter habitat During this time males compete for dominance with behaviors like horn clashes Breeding takes place in late fall generally November and December Lambing occurs between late April and early July on safe precipitous rocky slopes most lambs in the Sierra Nevada are born in May and June Ewes and lambs often occupy steep terrain that provides a diversity of exposures and slopes for escape cover 4 Habitat EditSierra bighorn are found in portions of the Sierra Nevada from Yosemite National Park to Olancha Peak Habitat occurs from the eastern base of the range as low as 1 460 m 4 790 ft to peaks above 4 300 m 14 100 ft Sierra bighorn inhabit open areas where the land is rocky sparsely vegetated and characterized by steep slopes and canyons Wehausen 7 provides a detailed description of Sierra bighorn habitat throughout their range Bighorn prefer open ground with high visibility to better detect predators and allow enough time to reach steep rocky areas escape terrain Forests and thick brush are usually avoided if possible 4 Most bighorn live at elevations from 3 000 4 300 m 10 000 14 000 ft in subalpine and alpine areas during the summer During winter some bighorn occupy high elevation windswept ridges while others migrate to lower elevations to avoid deep snow and to find forage 4 Diet Edit Herd at Wheeler Crest Sierra bighorn are ruminant herbivores with four chambered stomachs 6 Bighorn are primarily grazers consuming various grasses forbs and woody vegetation depending on season and location Naturally occurring mineral licks provide necessary minerals for bone and muscle growth 4 Endangerment EditCenturies of unregulated hunting disease outbreaks and mountain lion predation took a heavy toll on the Sierra bighorn population However disease played the largest role in the decline of the subspecies with domestic sheep transmitting virulent diseases in particular pneumonia from Pasteurella beginning in the 1870s 8 By the 1970s about 250 animals remained occupying only two small areas of their former vast range Translocations by the California Department of Fish and Wildlife CDFW helped to reestablish bighorn herds in historic habitat but in spite of these efforts the population hit a low of about 100 total individuals in 1995 9 On January 3 2000 Sierra bighorn were listed as a federally endangered subspecies 4 Species recovery EditIn 1999 CDFW was made the lead agency responsible for implementing Sierra bighorn recovery A group of stakeholders drafted the Sierra Nevada Bighorn Sheep Recovery Plan and CDFW formed the Sierra Nevada Bighorn Sheep Recovery Program to work toward the goals of the Recovery Plan 10 Since then conditions have been particularly favorable for population growth with the total number of individuals reaching about 250 by 2002 11 and about 600 in 2016 5 The Recovery Program continues to monitor population growth habitat use and cause specific mortality of Sierra bighorn and to carry out augmentations and translocations in an effort to achieve recovery goals 10 In 2014 fourteen Sierra Nevada bighorn sheep were flown to Big Arroyo in Sequoia National Park via helicopter to establish a population on the western side of the Sierra Crest 12 References Edit Sierra Nevada Bighorn sheep Ovis canadensis sierrae species profile Environmental Conservation Online System United States Fish and Wildlife Service March 3 2010 Wehausen J D V C Bleich R R Ramey II 2005 Correct Nomenclature for Sierra Nevada Bighorn Sheep PDF California Fish and Game 91 3 216 218 Archived from the original PDF on 2006 09 06 Retrieved 2006 07 16 Buchalski Michael R Sacks Benjamin N Gille Daphne A Penedo Maria Cecilia T Ernest Holly B Morrison Scott A Boyce Walter M 2016 Phylogeographic and population genetic structure of bighorn sheep Ovis canadensis in North American deserts Journal of Mammalogy 97 3 823 838 doi 10 1093 jmammal gyw011 PMC 5993094 PMID 29899578 a b c d e f g This article incorporates public domain material from Designation of Critical Habitat for the Sierra Nevada Bighorn Sheep Ovis canadensis sierrae and Taxonomic Revision Final Rule Fish and Wildlife Service 73 FR 45534 a b c d e Sierra Nevada Bighorn Sheep Facts California Department of Fish and Wildlife Retrieved 2018 05 05 a b c Physical Characteristics Sierra Nevada Bighorn Sheep Foundation Archived from the original on 2013 10 29 Retrieved 2013 10 23 Wehausen J D 1980 Sierra Nevada bighorn sheep history and population ecology Ph D thesis Univ Michigan Ann Arbor pp 18 25 Evaluation of Priorities and Costs in Species Recovery Plans Sonoran Pronghorn Louisiana Black Bear and Sierra Nevada Bighorn Sheep PDF Thesis The Evergreen State College April 2013 Retrieved 2016 03 26 US Fish and Wildlife Service endangered species recovery plan for the Sierra Nevada Bighorn Sheep PDF Retrieved 2005 06 13 a b Sierra Nevada Bighorn Sheep Recovery Program California Department of Fish and Wildlife Retrieved 2013 10 24 Sierra Nevada Bighorn Sheep Recovery Report 2003 PDF Archived from the original PDF on 2006 09 28 Retrieved 2006 11 17 Boxall Bettina April 10 2014 Bighorn sheep get a helicopter ride to the Sierra west side Los Angeles Times Sierra Nevada bighorn sheep at Wikipedia s sister projects Media from Commons Taxa from Wikispecies Retrieved from https en wikipedia org w index php title Sierra Nevada bighorn sheep amp oldid 1117873139, wikipedia, wiki, book, books, library,
