Effective species conservation requires understanding environmental effects on stage-specific demographics driving population change. Northern Bobwhite (Colinus virginianus) is an early-successional shrub-obligate species that has experienced long-term, range-wide declines due to fire suppression, agricultural intensification, and sprawling development. Local habitat features and landscape context may interactively influence vital rates. Management affects food, cover, and other resources available locally, while surrounding landscapes often determine degree of isolation and predator communities. We evaluated relationships between juvenile bobwhite survival and local (50 m) and landscape (1 km) scale cover type composition and grassland management (i.e. conservation grazing, prescribed burns, mowing/haying) on 3 native grasslands and 2 traditionally managed conservation areas in southwest Missouri, USA, 2016–2018. We radio-tracked brood-attending adults and young from hatch to a maximum of 114 days and estimated juvenile survival with a Bayesian known-fate logistic exposure model. Juvenile survival was greatest on native grasslands that were burned and grazed at least once in the previous 2 years. Percent shrub cover was positively related to survival. Survival was relatively high in local agriculture, but these relationships were sensitive to surrounding landscape composition. For example, small patches of cropland surrounded by nonagriculture such as strip crops surrounded by grassland units on traditionally managed sites had low survival. Relationships between survival and agricultural landscape cover were dependent on local cover types; survival was high within crop fields but low in non-native grasslands surrounded by crop fields such as agricultural field borders. Patch-burn grazing practices on native grasslands provided the best habitat for bobwhite juvenile survival. Agricultural landscapes can support the recruitment of bobwhite if appropriately managed native grasslands are also available.
LAY SUMMARY
Local vegetation structure and composition shaped by habitat management practices can drive bird population dynamics, and the magnitude and direction of relationships may vary depending on composition of the surrounding landscape. Thus, effective conservation planning requires understanding the effects of both local management and landscape context on survival and recruitment of sensitive species such as Northern Bobwhite (Colinus virginianus).
While Northern Bobwhites occupy many early successional and agricultural landscapes, habitat-specific survival probabilities during this vulnerable life stage are unknown.
We estimated juvenile survival from hatch to 90 days using nest monitoring, brood capture, and radio-telemetry data within a logistic exposure model.
Across our 5 study sites in southwest Missouri, juvenile survival was greatest on local native grasslands managed with fire and grazing. Juvenile survival was relatively high in agricultural crop fields but low in non-native field borders and in strip crop fields. Relationships between survival and local cover type varied depending on proportion of agricultural land cover in the surrounding landscape.
Native grassland management using fire and grazing may better support Northern Bobwhite juvenile survival and recruitment compared with management that includes food plots and planted strips of woody vegetation.
