Prescribed burn frequency, vegetation cover, and management legacies influence soil fertility: Implications for restoration of imperiled pine barrens habitat

• Published in: Forest ecology and management 2020-08, Vol.470-471, p.118163, Article 118163
• Main Authors: Quigley, Kathleen M., Kolka, Randall, Sturtevant, Brian R., Dickinson, Matthew B., Kern, Christel C., Donner, Deahn M., Miesel, Jessica R.
• Format: Article
• Language: English
• Subjects: Fire regimes; Forest; Nutrients; Ordination; Prescribed fire; Savanna
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/j.foreco.2020.118163

[Display omitted] •Variation in nutrient stocks related to vegetation cover and burn history.•Most soil nutrient variation restricted to forest floor (i.e. organic horizon).•Barrens soils depleted in total C, organic matter, K, and Ca stocks relative to other cover types.•Lower soil pH, P, and Mg at sites with >60 years of fire exclusion than at managed sites.•Weak evidence of historic land cover and management legacies on soil properties of extant barrens. In fire-dependent ecosystems, the absence of fire can contribute to a positive feedback in which increased vegetation cover leads to increased accumulation of soil organic matter and nutrient stocks. These changes in turn can influence competitive shifts among plant communities, resulting in increased woody plant establishment, canopy closure, and ultimately leading toward mesophication. Poor soil conditions may be especially important for maintaining the open structure characteristic of pine barrens ecosystems, which are imperiled due to loss of key ecosystem processes such as fire and land conversion to cropland or pine plantations. Our objectives were to determine how soil characteristics are related to recent prescribed fire management, and how soils vary along gradients of current and historic vegetation cover in a barrens-forest mosaic in northern Wisconsin, USA. We sought to understand whether management with prescribed fire shifts soils toward barrens-type soil conditions, and whether soil conditions typify barrens habitat relative to shrub and forest habitat We analyzed organic (i.e. forest floor) and mineral soil horizons collected along gradients of recent prescribed burn history and current (barrens, pine woodlands, brush, and closed-canopy forest) and historic vegetation cover types (barrens, pine plantations, deciduous forests) to investigate the influence of each on specific components of soil fertility. Using a model selection approach, we found forest floor soil properties were most frequently associated with differences in current vegetation cover; for instance, pine woodland sites had greater organic matter stocks than barrens sites, and cation stocks were generally greater at brush sites than barrens and pine woodland sites. Some soil properties, including pH, however, appeared to be driven by prescribed burn frequency. Using ordination techniques to characterize multidimensional characterizations of soils, we identified a soil legacy effect related to historic vegetation cover and l