An icon of conservation biology: molecular ecology of greater prairie chicken (Tympanuchus cupido pinnatus) in Illinois

The Greater Prairie Chicken (GPCH), a once abundant bird in Illinois, declined to fewer than 50 individuals prior to genetic rescue in 1992-1998 manifested by annual translocations of birds from out-of-state populations. These efforts partially restored genetic variability lost through historic inbreeding and low population sizes, yet retention of long-term diversity remains questionable, particularly in light of continued population declines, geographic isolation, and a lek mating system. This study re-evaluated genetic variability of the GPCH populations at the Prairie Ridge State Natural Area (PRSNA) in Illinois by amplifying 24 microsatellite loci using genomic DNA extracted from shed feathers. Genetic profiles accrued from 1,229 feathers identified 74 individuals, and were used to derive population genetic parameters including relatedness, population structure, and gene flow. GPCH showed remarkable lek fidelity. Some individuals (3%) moved among leks within counties but none moved between counties. Bayesian cluster analyses reinforced these data by identifying population substructure at two levels: county and family group. To facilitate comparisons with earlier studies, all analyses were conducted using the full suite of 24 loci, and a reduced panel of 6 (from earlier studies). These comparisons reveal that post-translocation genetic diversity was largely retained in Jasper County, but corresponded in Marion County to characteristics of bottlenecked populations. Both microsatellite panels provided similar answers in the majority of analyses, although the reduced panel failed to elucidate population substructure. This project highlights the necessity of continued genetic monitoring of small populations that elicit conservation concern. These data will promote an ongoing recovery effort with this iconic Illinois species by gauging the success of past conservation actions while guiding future management and restoration efforts