Abstract
Open forest ecosystems are considered one of the most imperiled
ecosystems in North America and many associated avian species are
experiencing population declines. Management at large and impactful
scales is challenging on private lands due to fragmentation and resource
limitations, but public lands are often larger in scale and offer
opportunities for landscape level conservation of species of
conservation concern. Northern bobwhite (Colinus virginianus; bobwhite)
is a popular but declining game bird which is often considered an
umbrella and indicator species for savanna ecosystems. To evaluate the
effects of tree canopy cover and prescribed fire frequency (1 Jan 2010
– 15 May 2024) on bobwhite occupancy we surveyed 144 sites 11 times
during 15 May – 17 June 2024 using acoustic recording units on the
Sabine and Angelina National Forests of Texas. Probability of bobwhite
occupancy decreased as canopy cover increased (βTree = -0.74, 95% CrI:
-1.29 – -0.28); occupancy was over 19 times higher when canopy cover
was 44% versus the mean observed value of 80.8% (range: 38–96%).
Despite a well-established positive relationship of bobwhite and
prescribed fire based on previous research, we found tree canopy
obfuscated any effects of fire frequency on bobwhite occupancy (βFire =
-0.09, 95% CrI: -0.57 – 0.43). Only 2 of 144 sites were characterized
by low-moderate canopy cover (<50%) with a moderate fire
frequency (burned 5 and 7 times since 2010). Our results underscore the
importance of forest thinning in addition to prescribed fire for
managing species which require savanna conditions.