Biology Ph.D. Dissertations

The Evolutionary History, Demographic Independence and Conservation Status of Two North American Prairie Bird Species: The Greater Prairie Chicken and the Lark Sparrow

Date of Award

2011

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Biological Sciences

First Advisor

Juan L. Bouzat

Second Advisor

Helen J. Michaels (Committee Member)

Third Advisor

Karen V. Root (Committee Member)

Fourth Advisor

Moira J. van Staaden (Committee Member)

Fifth Advisor

Arthur S. Brecher

Abstract

Prairie birds of North America have been greatly affected by habitat losses over the past two centuries. However, the exact extent of losses and the vulnerability of regional populations within prairie birds are often vague or scientifically untested. In the present body of work I have studied two species of North American birds, the greater prairie chicken (Tympanuchus cupido) and the lark sparrow (Chondestes grammacus). Within each species I addressed major aspects of their evolutionary and recent history, and whether patterns of demographic independence within each species warrant separate management and conservation of regional populations. In the case of T. cupido a putative expansion of the species into the northern Great Plains was evaluated using provenance data from museum specimens, mitochondrial DNA (mtDNA) analysis of museum and contemporary samples, and an exhaustive search of historical accounts from early explorers. Data from this study indicated that the expansion hypothesis was unrealistic for the species, did not concur with DNA patterns between the “expanded” and “original” ranges, and seemingly overlooked multiple detailed accounts of T. cupido in central Canada long before the proposed time of expansion. Studies of C. grammacus likewise examined mtDNA patterns within the species, but also incorporated data from nuclear microsatellite DNA, morphological traits, and song. These datasets all indicated emergent patterns of demographic independence among regional breeding areas of C. grammacus. Furthermore, song analyses indicated that this species sings some of the highest performance trills in the bird world, and that within the species vocal performance was regionally-structured and directly correlated with beak morphology. These findings have direct implications for not only understanding the regional evolutionary history and conservation needs of C. grammacus, but also contribute much to the study of evolutionary processes within Neotropical migrants and songbirds in general. As a whole, the present dissertation expands the scientific understanding of the past evolution, recent histories, and present conservation needs of North American prairie birds.

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