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

Abstract

The idea that not all fire regimes are created equal is a central theme in fire research and conservation. Fire frequency (i.e., temporal scale) is likely the most studied fire regime attribute as it relates to conservation of fire-adapted ecosystems. Generally, research converges on fire frequency as the primary filter in plant community assembly and structure, which is often critical to conservation goals. Thus, conservation success is commonly linked to fire frequency in fire regimes.The spatial scale of fire may also be vital to conservation outcomes, but this attribute is underrepresented in the primary literature. In our global, contemporary literature search, we found 37 published syntheses concerning the effects of prescribed fire in conservation over the last decade. In those syntheses, only 16% included studies that reported data-based inferences related to the spatial scale of the fire, whereas 73% included discussion of empirical studies on the temporal scale. Only one of the syntheses discussed studies that explicitly tested the effects of spatial extent, and none of those studies were experiments manipulating spatial scale. Further, understanding spatial-scale-dependent patterns may be relevant because two databases of fire-occurrence data from the United States indicated that spatial scale among lightning-ignited and prescribed fires may have been mismatched over the past few decades.Based on a rich ecological literature base that demonstrates pervasive scale-dependent effects in ecology, spatial-scale-dependent relationships among prescribed fire regimes and conservation outcomes are likely. Using examples from the southeastern United States, we explored the potential for scale-dependent ecological effects of fire. In particular, we highlighted the potential for spatial scale to (a) influence wildlife populations by manipulating the dispersion of habitat components, and (b) modulate plant community assembly and structure by affecting seed dispersal mechanics and spatial patterns in herbivory. Because spatial-scale-dependent outcomes are understudied but likely occurring, we encourage researchers to address the ecological effects of spatial scale in prescribed-fire regimes using comparative and manipulative approaches.

Human‐mediated trophic mismatch between fire, plants and herbivores

“…And, phenology is only one of the understudied characteristics of anthropogenic fire regimes that are likely mismatched and could have consequences to trophic interactions. Spatial scale of anthropogenic fires also need to be studied simultaneously in this context (Mason and Lashley 2021). In fact, in the southeastern USA, the top two lightning season fire months meet the fire policy requirements to gain a permit based on weather conditions < 10% of the time (Chiodi et al 2018).…”

Experimentally testing animal responses to prescribed fire size and severity

“…The spatial scale of burning is frequently mentioned in prescribed fire studies but rarely examined quantitatively (Mason & Lashley, 2021). Additionally, prescribed burning studies often place multiple survey sites within a single burn scar, whereas we examined 10 independent burns varying in size and severity.…”

Genomic reaction norms inform predictions of plastic and adaptive responses to climate change

“…Therefore, failing to account for spatially structured adaptive variation in conservation and management plans can erode both the population of interest and ecosystem functioning as a whole. However, governance structures, such as jurisdictional entities responsible for forestry and fisheries management, typically operate on unduly broad scales, making assessment across multiple spatial scales ideal for informing effective and feasible conservation strategies in many cases (Mason & Lashley, 2021; Oppel et al, 2018; Price et al, 2004).…”