Nicholas J. Parker

Megafires (wildfire >10,000 ha) are increasing worldwide and pose a novel threat to wildlife in fragmented landscapes. Within the southern Great Plains, 70% of grasslands have been lost to conversion to row‐crop agriculture, energy development, and invasive woody species. Multiple contemporary megafires have burned remaining large grassland tracts that provide high‐quality habitat for lesser prairie‐chickens ( Tympanuchus pallidicintus ). Grasslands and wildlife in this region evolved with fire, and studies demonstrate benefits of smaller fires for lesser prairie‐chickens. However, wildlife response to the scale and severity of megafire in contemporary fragmented grasslands remains undocumented. We used a hierarchical approach to assess lesser prairie‐chicken response to megafire, evaluating individual space use, habitat selection, and lek attendance in relation to landscape habitat features for 2 years before (2014−2015) and 2 years after (2018−2019) a 2017 megafire in the mixed‐grass prairie of south‐central Kansas, USA (Starbuck fire ~266,000 ha). The area used by individual lesser prairie‐chickens did not differ in size before (828 ± 110 ha [SE]) and after (720 ± 101 ha) the fire based on 95% isopleth Brownian bridge home ranges, but lesser prairie‐chickens shifted the location of home ranges to include 4 times more cover of United States Department of Agriculture Conservation Reserve Program (CRP) fields after the fire. Individual habitat selection revealed lesser prairie‐chickens selected more overall grassland (β = 0.19 ± 0.04) and avoided cropland (β = −0.18 ± 0.03) post fire. However, at the population level, male lek attendance was greater in landscapes (7,854 ha) with more cropland post fire, opposite of trends before the fire. Lesser prairie‐chickens avoided more severely burned areas during the 3 years post fire across all analyses. Both individual‐ and population‐level analyses suggested that more marginal CRP and cropland landscapes provided refugia following the megafire. Increased megafire risk may reduce lesser prairie‐chicken habitat and drive dispersal to lower quality, marginal, fragmented landscapes. Habitat in more marginal landscapes may play an important role in wildlife resilience and resistance to novel disturbance in contemporary fragmented grasslands.

Recent studies have documented benefits of small, prescribed fire and wildfire for grassland‐dependent wildlife, such as lesser prairie‐chickens (Tympanuchus pallidicintus), but wildlife demographic response to the scale and intensity of megafire (wildfire >40,000 ha) in modern, fragmented grasslands remains unknown. Limited available grassland habitat makes it imperative to understand if increasing frequency of megafires could further reduce already declining lesser prairie‐chicken populations, or if historical evolutionary interactions with fire make lesser prairie‐chickens resilient. To evaluate lesser prairie‐chicken demographic response to megafires, we compared lek counts, nest density, and survival rates of adults, nests, and chicks before (2014–2016) and after (2018–2020) a 2017 megafire in the mixed‐grass prairie of Kansas, USA (Starbuck fire ~254,000 ha). There was a 67% decline in attending males on leks post‐fire and a 57% decline in occupied leks post‐fire. Despite population declines as indicated by lek counts, adult female breeding season survival () was similar pre‐ ( = 0.65 ± 0.08 [SE]) and post‐fire (0.61 ± 0.08), as was chick survival (pre‐fire: 0.23 ± 0.07; post‐fire: 0.27 ± 0.11). Nest survival appeared lower post‐fire (pre‐fire: 0.38 ± 0.06; post‐fire: 0.20 ± 0.06), but did not differ at the 95% confidence interval. Nest density of marked females declined 73% in areas burned by megafire. Although lesser prairie‐chickens persisted in the study area and we documented minimal effects on most demographic rates, reduced lesser prairie‐chicken abundance and reproductive output suggests full recovery may take >3 years. Increased propensity for megafire resulting from suppression of smaller fires, compounded by climate change and woody encroachment, may impose a short‐term (3–5 year) threat to already declining lesser prairie‐chicken populations.