Meta-analysis of avian and small-mammal response to fire severity and fire surrogate treatments in U.S. fire-prone forests

Abstract

Abstract. Management in fire-prone ecosystems relies widely upon application of prescribed fire and/or fire surrogate (e.g., forest thinning) treatments to maintain biodiversity and ecosystem function. Recently, published literature examining wildlife response to fire and fire management has increased rapidly. However, none of this literature has been synthesized quantitatively, precluding assessment of consistent patterns of wildlife response among treatment types. Using meta-analysis, we examined the scientific literature on vertebrate demographic responses to burn severity (low/moderate, high), fire surrogates (forest thinning), and fire and fire surrogate combined treatments in the most extensively studied fire-prone, forested biome (forests of the United States). Effect sizes (magnitude of response) and their 95% confidence limits (response consistency) were estimated for each species-by-treatment combination with two or more observations. We found 41 studies of 119 bird and 17 smallmammal species that examined short-term responses ( 4 years) to thinning, low/moderateand high-severity fire, and thinning plus prescribed fire; data on other taxa and at longer time scales were too sparse to permit quantitative assessment. At the stand scale (,50 ha), thinning and low/moderate-severity fire demonstrated similar response patterns in these forests. Combined thinning plus prescribed fire produced a higher percentage of positive responses. High-severity fire provoked stronger responses, with a majority of species possessing higher or lower effect sizes relative to fires of lower severity. In the short term and at fine spatial scales, fire surrogate forest-thinning treatments appear to effectively mimic low/moderate-severity fire, whereas low/moderate-severity fire is not a substitute for high-severity fire. The varied response of taxa to each of the four conditions considered makes it clear that the full range of fire-based disturbances (or their surrogates) is necessary to maintain a full complement of vertebrate species, including fire-sensitive taxa. This is especially true for high-severity fire, where positive responses from many avian taxa suggest that this disturbance (either as wildfire or prescribed fire) should be included in management plans where it is consistent with historic fire regimes and where maintenance of regional vertebrate biodiversity is a goal.

Pyrodiversity promotes avian diversity over the decade following forest fire

“…patches of unburned vegetation, snags, downed wood), burned habitats cannot be considered entirely equivalent to early seral states. Much attention has been focused on how communities of organisms change from before to immediately after fires [24,25], or whether communities show resilience to fire over multi-decadal time frames (e.g. 20-100 years) [10,26,27], with little focus on how communities change during the potentially transformative early years following fire.…”

The use of response measures in meta-analyses of land-use impacts on ecological communities: a review and the way forward

“…Grouping species into relevant niches or categories is not always an easy task (Fontaine and Kennedy 2012). Hence, this approach demands good knowledge of the species' ecologies.…”

Effects of fuel treatments on California mixed-conifer forests

“…A meta-analysis of avian and small-mammal responses to wildfire, thinning, and thinning plus prescribed fire showed that most short-term responses at fine spatial scales mimicked species responses to low-and moderateseverity wildfire (Fontaine and Kennedy 2012). The majority of the responses to the fuel treatments were neutral; thinning combined with prescribed fire had the most positive species responses; and species responded to high-severity wildfire with the strongest reaction (both positive and negative) (Fontaine and Kennedy 2012).…”

“…Several wildlife species in the Sierra Nevada utilize the forest structure and early-successional conditions that occur following a high-severity fire, which are not well approximated by prescribed fire or thinning treatments (Fontaine and Kennedy 2012;Hutto 2008;. The black-backed woodpecker, a post-fire specialist that searches for insects in dead trees, may benefit from firescorched dead trees following prescribed fires with high intensities, or from leaving clumps of dense trees during thinning operations that can subsequently burn at higher severities (Hutto 2008).…”

“…to include canopy gaps or patches of highseverity fire, either through mechanical treatments, prescribed fire or managed wildfire (Fontaine and Kennedy 2012 ).…”