Fire, fungi, flora, and flow: post-fire fungal community assemblages, vegetation establishment, and soil hydrophobicity in forests of the southern Rocky Mountains
Date
2023
Journal Title
Journal ISSN
Volume Title
Abstract
Wildfire is an important ecological driver of ecosystem dynamics in the southern Rocky Mountains at multiple landscape scales, guiding establishment of forest biota both aboveground and below. Size, frequency, and severity of wildfires in coniferous forests across the western United States is increasing at an unprecedented rate. Despite wildfire's significant but disparate influences on forest soils, post-fire research has often focused on aboveground vegetation in isolation from study of belowground soil characteristics and the fire ecology of soil biota. Fungi are vital to forest ecosystems for their functional roles, however, the effects of wildfire on forest-specific fungal communities and how those communities subsequently influence post-fire vegetation communities and soil environments has not been extensively researched in the region over the past several decades. This is a prominent knowledge gap, especially as fungi are highly variable across functional groups, space, and time even in unburned systems. Thus, to build on our understanding of contemporary fire ecology in forested ecosystems of the Southern Rockies, we investigate three wildfires that burned in the state of Colorado during the 2020 fire season and address three research objectives: 1) Examine the influence of forest type and fire severity on post-fire fungal community composition across soil depth and temporal gradients; 2) Determine the effects of post-fire fungal community diversity on forest understory plant diversity and abundance; and 3) Explore relationships between fungal assemblages and observed soil hydrophobicity in burned forested environments. We found that though fire severity and soil depth were the primary influences on quantified fungal diversity, the composition of fungal community assemblages was most heavily influenced by forest type: forests developed fungal communities compositionally unique to one another just two years after fire. Diversity of fungi showed significant influence on aboveground plant diversity and abundance, especially mutualistic fungi (ecto- and arbuscular mycorrhizae) and their respective plant hosts. Finally, significant relationships between fungal diversity and soil hydrophobicity were observed mediated by forest type, fire severity, soil depth, and year post-fire, though these patterns were difficult to surmise and the influence of other important variables may be at play. By more fully understanding how soil fungi interact with aboveground vegetation establishment and belowground soil conditions after wildfire, this research may help inform managers of pathways to better achieve desired post-fire outcomes by leveraging fungal relationships in soil remediation, site preparation, and conservation of post-fire forest ecosystems.
Description
Rights Access
Subject
forest
hydrophobicity
wildfire
fungi
community ecology
southern Rocky Mountains