Lesser prairie‐chicken population forecasts and extinction risks: An evaluation 5 years post–Catastrophic drought

Abstract

ABSTRACT The lesser prairie‐chicken (Tympanuchus pallidicinctus) is a species of conservation concern resulting from long‐term declines in abundance due in part to loss and fragmentation of habitat. Habitat loss can affect landscape carrying capacity, and may exacerbate otherwise normal fluctuations in populations during periods of drought, anomalous weather, or other stochastic events. Previous work provided a unified long‐term (1965–2012) assessment of lesser prairie‐chicken population dynamics and projections of persistence in the Southern Great Plains. Despite the final year of data collection coinciding with a record‐setting drought, lesser prairie‐chicken populations exhibited reasonable probabilities of persistence for 3 of the 4 ecoregions in which they occur. Our objective was to validate previous population forecasts with 4 years of additional data (post‐drought). We assessed long‐term (1964–2016) changes in lesser prairie‐chicken populations, using reconstructed population abundances from lek count and aerial survey data, and projected likely future probabilities of persistence. Based on our validations, model forecasts appear to provide a reasonable ability to project population abundance in the near term (∼5 yr). Population abundances have largely edged upward since the extreme drought conditions of 2011–2012. Additionally, near‐term extirpation risks have been reduced measurably for 3 of the 4 ecoregions and the range‐wide population as a result of increased annual growth rates. Meta‐population analysis indicated that each ecoregion had similar likelihoods of persistence as estimated independently for each single population, (i.e., without gene flow), but the longest term probability of extinction for the range‐wide meta‐population (i.e., with gene flow) was reduced by half as compared to the range‐wide population modeled with disconnected subpopulations (i.e., ecoregions). Regardless, our results continue to support the importance of maintaining connectivity between ecoregions and core areas therein. © 2017 The Wildlife Society.

Keywords

• carrying capacity
• density‐dependent
• lesser prairie‐chicken
• meta‐population
• population reconstruction
• population viability