Spatial Scale and Shape of Prescribed Fires Influence Use by Wild Turkeys

Abstract

In recent years, there have been increasing efforts to understand effects of prescribed fire on population dynamics of wild turkeys (Meleagris gallopavo; turkeys) in pine (Pinus spp.) forests. Although distribution of turkeys is not limited to pine forests, these forests provide nesting and brood-rearing habitat throughout the southeastern United States. Previous studies have investigated direct (e.g., nest loss to fire) and indirect (e.g., nest-and brood-site selection) effects of prescribed fire, but little is known about how turkeys are influenced by the spatial scale and shape of prescribed fire. We constructed an individual-based model (IBM) with landscapes of 2 burn unit shapes and 17 spatial scales. We used telemetry data obtained from global positioning system-marked female turkeys to replicate movement behaviors of turkeys within the model. We hypothesized that use of units burned during the current year (<1 yr) would decrease as scale of fires increased, and that shape of burn units would influence use by turkeys. Spatial scale most influenced turkey use; the greatest use was in burned stands of approximately 23 ha in size, whereas least use was associated with burned stands >1,269 ha. At a spatial scale of 23 ha, the daily percent use of rectangular burn units was 7% greater than square-shaped burn units. Likewise, daily percent use of rectangular burn units was 34% greater than square-shaped burn units at a spatial scale of 1,269 ha. When burn units were rectangular-shaped, daily percent use decreased by 48% as the spatial extent of the fires increased from 23 ha to 203 ha. Likewise, when burn units were square-shaped, turkey use decreased by 49% as spatial extent of fires increased from 23 ha to 203 ha. Our findings suggest the importance of managing forested landscapes with prescribed fires not exceeding approximately 200 ha if wild turkeys are a management concern.

Spatial scale in prescribed fire regimes: an understudied aspect in conservation with examples from the southeastern United States

“…However, edge species are likely to have some threshold in burn-block size where habitat components within the burn block interior are too far from those provided in unburned areas, rendering the interior portion of the burn block unusable. For example, Cohen et al (2019) demonstrated that eastern wild turkeys (Meleagris gallopavo, Linnaeus 1758) were unlikely to use the interior of burn blocks when greater than 250 m from an unburned edge, and Sullivan et al (2020) found that turkey use was highest in smaller burn blocks (23 ha). Even so, this species is capable of traveling much longer distances, and fire consistently produces desirable plant community structure for that species (Chance et al 2019).…”

Prescribed Fire Size, Patchiness, and Pyrodiversity in the Southeastern United States

“…Many organisms are drawn to edges because they can use each habitat to meet different needs (Wiens 1976;Harris 1988). However, the amount of edge and area within a burned or unburned patch affects habitat use differently (Sullivan et al 2020) and can facilitate predation on some organisms. Habitat use can therefore be influenced by tradeoffs, such as the one between needing food and risking attack by predators (Cherry et al 2017).…”

“…For example, research suggests that burn blocks of 40-60 acres, with 50% of them burned annually, support nesting areas and food for northern bobwhite quail (Palmer and Sisson 2017;Rosche et al 2019). Studies recommend burning 12%-33% of burn blocks (Wann et al 2020) that are between 50 and 500 acres (Chamberlain 2019;Sullivan et al 2020) to support habitat needs when managing wild turkeys. If management objectives include supporting a broader variety of species, consider changing the size of a fire in a given area for each burn.…”