Document Type

Thesis - Open Access

Award Date

2021

Degree Name

Master of Science (MS)

Department / School

Natural Resource Management

First Advisor

Jonathan Jenks

Keywords

Badlands National Park Bighorn Sheep Disease Population Genetics Survival

Abstract

Within the last century, bighorn sheep (Ovis canadensis) in the badlands ecosystem of western South Dakota have been subjected to complete extirpation, reintroduction, disease die-offs, genetic bottlenecking, and population augmentation. Subsequently, the population in Badlands National Park (BNP) appears to have recovered, but it was unknown to what degree past events had influenced the population. From 2017-2019, we conducted research on 5 subherds within 2 management units in BNP to 1) survey for the presence of respiratory pathogens and estimate the prevalence of other potentially infectious diseases; 2) assess adult and lamb survival and cause-specific mortality; 3) estimate population size and growth; 4) evaluate the risk of disease exposure from domestic livestock operations within 8 km of the North Unit of BNP; and 5) evaluate genetic variation and population structuring and differentiation. We sampled (n = 83) individuals for the presence of respiratory pathogens including Mycoplasma ovipneumoniae (Movi). Movi results were PCR negative and serology positive (18% prevalence). Bacteriology results indicated additional respiratory pathogens (e.g., Bibersteinia trehalosi, Pasteurella species, Mannheimia species, Trueperella pyogenes) were present within the population. We radio-collared 49 adults and 53 lambs to monitor survival and cause-specific mortality. Overall adult and lamb survival was 96% (95% credible interval [CI] = 89%, 99%) and 82% (CI = 65%, 92%), respectively, with predation accounting for 56% of lamb mortalities. We documented 5 domestic sheep and goat operations within 8 km of the North Unit of BNP. Two goat operations were sampled for respiratory pathogens, one of which testing PCR positive for Movi (77% prevalence). We estimated population growth of πœ† = 1.17 in 2016-2017 and πœ† = 1.22 in 2017-2018 with a minimum population size count of 233 in 2018. Genetic analysis was conducted at 15 microsatellite loci from 75 individual samples. Overall genetic variation for the BNP population was consistent with other native and translocated populations of bighorn sheep across their range. We found averages of 5.80 and 0.65 for allelic diversity and heterozygosity levels, respectively. We identified three genetically distinct clusters recognized as the three source herds used to establish and supplement the BNP population between 1967 and 2014. Disease and genetic variation were not impacting the growth and survival of the BNP population. As the population continues to have high survival and growth, disease exposure from contact with domestic livestock operations appears to be the greatest risk to the population in the future.

Library of Congress Subject Headings

Bighorn sheep -- South Dakota -- Badlands National Park.
Mammal populations -- South Dakota -- Badlands National Park.

Number of Pages

99

Publisher

South Dakota State University

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Rights Statement

In Copyright