SREL Reprint #2598

Mitochondrial DNA variation among wintering midcontinent gulf coast sandhill cranes

Travis C. Glenn1,2, Jonathan E. Thompson3, Bart M. Ballard3, Jay A. Roberson4, and Jeffrey O. French1,2

1Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
2Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802, USA
3Caesar Kleberg Wildlife Research Institute, MSC 218, Texas A&M University-Kingsville,
700 University Boulevard, Kingsville, TX 78363, USA
4Texas Parks and Wildlife Department, 4200 Smith School Road, Austin, TX 78744, USA

Abstract: Based on morphological characteristics, 3 subspecies of sandhill cranes (Grus canadensis)—the lesser sandhill crane (G. c. canadensis), Canadian sandhill crane (G. c. rowani), and greater sandhill crane (G. c. tabida)—occur within the midcontinent population (MCP) and winter along the Gulf Coast of Texas, USA. Of these subspecies, the greater sandhill crane is the least abundant and the most restricted in distribution in the midcontinent region, making it a subspecies of special concern. Twenty individuals from each subspecies with the highest posterior probabilities of membership in subspecies associated with their morphological discriminant score (i.e. those individuals that were least likely to be misclassified based on the morphological model currently used to assign wintering individuals to subspecies) were chosen from a total sample of 220 birds. We amplified and sequenced a 437-base-pair segment from domain I of the mitochondrial DNA (mtDNA) control region for these 60 birds. Analyses of the resulting 41 different mtDNA haplotypes indicate that birds classified as Canadian and greater sandhill cranes based on their morphology do not differ genetically, but lesser sandhill cranes are genetically distinct from both Canadian and greater sandhill cranes. When Canadian and greater sandhill cranes are grouped together, 55 of the 60 individuals sequenced are consistently classified using morphology and mtDNA. We then used the DNA sequences to develop a simple restriction enzyme assay of this mtDNA segment to survey an additional 160 specimens. These results indicate that (1) mtDNA assays provide reliable discrimination of migratory sandhill cranes, (2) the current subspecific designations of sandhill cranes may not accurately reflect genetic structure in this species, (3) concern for preserving the genetic diversity of sandhill cranes in the midcontinent region may not need to focus on management of greater sandhill cranes wintering in the sampled populations, and (4) studies of individuals from the breeding grounds are clearly needed to determine whether Canadian and greater sandhill cranes are indeed distinct subspecies.

Key words: crane, genetics, Grus canadensis, Gulf Coast, mitochondrial DNA, sandhill crane, subspecies, Texas

SREL Reprint #2598

Glenn, T. C., J. E. Thompson, B. M. Ballard, J. A. Roberson, and J. O. French. 2000. Mitochondrial DNA variation among wintering midcontinent gulf coast sandhill cranes. Journal of Wildlife Management. 66:339-348.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).