Maintenance of Genetic Diversity Despite Population Fluctuations in the Lesser Prairie-Chicken (Tympanuchus pallidicinctus)

Abstract

Assessments of genetic diversity, structure, history, and effective population size (N_e) are critical for the conservation of imperiled populations. The lesser prairie-chicken (Tympanuchus pallidicinctus) has experienced declines due to habitat loss, degradation, and fragmentation in addition to substantial population fluctuations with unknown effects on genetic diversity. Our objectives were to: (i) compare genetic diversity across three temporally discrete sampling periods (2002, 2007–2010, and 2013–2014) that are characterized by low or high population abundance; (ii) examine genetic diversity at lek and lek cluster spatial scales; (ii) identify potential bottlenecks and characterize genetic structure and relatedness; and (iii) estimate the regional N_e. We analyzed 194 samples across the shinnery oak prairie region of eastern New Mexico and western Texas using 13 microsatellite loci. Mean heterozygosity, allelic richness, and inbreeding coefficient were not significantly different between discrete sampling periods, suggesting that this population has maintained its genetic diversity across the sampled population fluctuations. We did not detect genetic structure using multiple Bayesian clustering approaches. Furthermore, there was no support for recent genetic bottlenecks, and we estimated that the N_e ranged from 229.5 (p_crit = 0.05, 95% CIs = 121.2–1023.1) to 349.1 (p_crit = 0.02, 95% CIs = 176.4–2895.2) during our final sampling period (2013–2014). Although we provide evidence for gene flow within this region, continued habitat loss and fragmentation that leads to population declines and isolation could increase the risk of genetic consequences. Continued monitoring of genetic diversity and increasing available habitat that supports robust populations of lesser prairie-chickens may improve the likelihood of the species' persistence.