Range-wide monitoring of population trends for Rocky Mountain bighorn sheep. (August 2020)

• Record Type: Journal Article
• Authors: Donovan, Victoria M.; Roberts, Caleb P.; Wonkka, Carissa L.; Beck, Jeffrey L.; Popp, Jesse N.; Allen, Craig R.; Twidwell, Dirac
• Is Part Of: Biological conservation. Volume 248(2020)
• Publication Date: 2020-08
• Subjects: Scale -- Translocation -- Ovis canadensis -- Reintroduction -- Population reinforcement -- Restoration; Conservation of natural resources -- Periodicals; Nature conservation -- Periodicals; Ecology -- Periodicals; Environment -- Periodicals; Environmental Pollution -- Periodicals; Electronic journals; 333.9516
• DOI: 10.1016/j.biocon.2020.108639
• Languages: English
• ISSNs: 0006-3207

Abstract

Abstract: Species conservation requires monitoring and management that extends beyond the local population, yet studies evaluating population trends and management outcomes across the spatial range of a species remain rare. We conducted the first range-wide assessment of population trends for the iconic Rocky Mountain bighorn sheep ( Ovis canadensis canadensis ) of North America to investigate links between population trends and translocation history. Millions of US dollars have been spent translocating bighorn sheep to achieve conservation objectives, yet a range-wide assessment is lacking. We collected bighorn sheep population estimates for 217 populations across ten US states and two Canadian provinces. We categorized each population by translocation status: native (populations received no translocations), augmented (native populations supplemented with translocation), or reintroduced (populations beginning from translocation). Fifty-eight percent of populations increased in recent years. While most reintroduced and native populations increased in the last 5 years of records, almost double the number of augmented populations declined compared to increased. Reintroduced and augmented populations from the north-central portion of bighorn sheep range declined the most in the last 5 years of records, while southern populations tended to be more stable. Although Rocky Mountain bighorn sheep appear to be a conservation and restoration success, the threat of local population loss remains high in certain regions. We show how amalgamating multi-jurisdictional population data can assist in determining wildlife status and assessing broad-scale management outcomes.