Implications of climatic heterogeneity for conservation of the Lesser Prairie‐Chicken (Tympanuchus pallidicinctus)

Abstract

Abstract. A geographic range is a heterogeneous matrix where the natural capability to support resident species varies from detrimental to optimal. Given this, the first priority for species conservation should be to determine where optimal environments exist. We used MaxEnt species distribution modeling to distinguish climatic characteristics associated with persistent leks from those at random locations in order to characterize the niche and potential distribution of the imperiled Lesser Prairie-Chicken (Tympanuchus pallidicinctus). Annual, brood period, and winter precipitation were the most important characteristics of the niche across the entire range, but maximum temperature during nesting was a key characteristic in the southern part of the range. Habitat suitability across the geographic range was multimodal but also consistent with a center-periphery pattern. Western Kansas and Oklahoma and east-central New Mexico contributed more than expected, whereas all other areas contributed less than expected, to habitat suitability of the geographic range. Lesser Prairie-Chickens appear constrained on the western edge of their range by abiotic factors, namely aridity, unfavorable temperatures and sandy soils. Conversely, they appear constrained on the eastern edge by biotic factors, namely transition from mid-grass to tallgrass prairie that results in dominance by the Greater Prairie-Chicken (Tympanuchus cupido). Conserving Lesser PrairieChickens will depend on maintaining persistent populations in western Kansas and Oklahoma and eastcentral New Mexico, as well as expanding its distribution across Texas. Aridity, unfavorable temperatures, and a paucity of habitat make eastern Colorado and southeastern New Mexico challenging areas for persistence of this species. Climate change may make it more difficult for populations in New Mexico and adjacent parts of Texas to persist, but more favorable for populations in eastern Colorado. The potential difficulties for populations in the southern part of the range will make it increasingly important to conserve populations in western Kansas and Oklahoma.

Causes of mortality and temporal patterns in breeding season survival of lesser prairie‐chickens in shinnery oak prairies

“…This hypothesis is supported by the fact that all male mortalities that occurred in June were in the drought years of 2009 and 2011. Our results corroborate similar findings presented in Grisham et al (2013) and Dunn and Milne (2014), which suggest that lesser prairiechickens in shinnery oak prairies live at the edge of their physiological tolerance for aridity, and that drought negatively affects the species through multiple mechanisms, including reduction of cover that protected the species from predators, as well as reduction in available food.…”

“…In particular, recent data are lacking on breeding season survival and causes and timing of mortality of lesser prairie-chickens in shinnery oak prairies. Shinnery oak prairies are semiarid grasslands, which experience hotter and drier environmental conditions compared with the rest of the species' distribution (Grisham et al 2013, Dunn andMilne 2014). Lesser prairie-chickens in this ecoregion are susceptible to drought, which results in inter-annual variation of nesting behavior (Grisham et al 2013(Grisham et al , 2014.…”

Interactive effects between nest microclimate and nest vegetation structure confirm microclimate thresholds for Lesser Prairie-Chicken nest survival

“…We did not separate first nest from renests in this analysis because of the low sample size of renests. Our microclimate candidate models were developed using information presented in Flanders-Wanner et al (2004), Fields et al (2006), Grisham et al (2013), Dunn and Milne (2014), and Hovick et al (2014) that suggested temperature and humidity as limiting factors for various aspects of Holarctic grouse reproductive ecology. We also included several exploratory models that included the proportion of extreme temperature and VPD measurements to assess whether extreme microclimate conditions influenced nest survival (Table 1).…”

“…We expected microclimate to influence nest survival similarly among the 3 ecoregions. We hypothesized that humidity would explain nest survival to a greater extent than other microclimate parameters for all 3 ecoregions (Grisham et al 2013, Dunn andMilne 2014). We expected nest survival probabilities to decrease as temperatures increased and humidity decreased across all ecoregions (Grisham et al 2013, Dunn andMilne 2014, Hovick et al 2014).…”

“…We hypothesized that humidity would explain nest survival to a greater extent than other microclimate parameters for all 3 ecoregions (Grisham et al 2013, Dunn andMilne 2014). We expected nest survival probabilities to decrease as temperatures increased and humidity decreased across all ecoregions (Grisham et al 2013, Dunn andMilne 2014, Hovick et al 2014). Our final hypothesis was that microclimate would be more important for nest survival than vegetation around the nest site as measured by visual obstruction reading (VOR; Pitman et al 2005, Hagen et al 2013, 2016a Dahlgren et al (2016), and Grisham et al (2016b) provide comprehensive reviews of the key plant species, climate data, population size, species management, and land cover and land use for Lesser Prairie-Chickens in the 3 ecoregions.…”