Articles | Volume 14, issue 17
Biogeosciences, 14, 3957–3969, 2017

Special issue: Biological soil crusts and their role in biogeochemical processes...

Biogeosciences, 14, 3957–3969, 2017

Research article 13 Sep 2017

Research article | 13 Sep 2017

Recovery of biological soil crust richness and cover 12–16 years after wildfires in Idaho, USA

Heather T. Root1, John C. Brinda2, and E. Kyle Dodson3 Heather T. Root et al.
  • 1Weber State University, Ogden, UT 84403, USA
  • 2Missouri Botanical Garden, P.O. Box 299, Saint Louis, MO 63166-0299, USA
  • 3Department of Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA

Abstract. Changing fire regimes in western North America may impact biological soil crust (BSC) communities that influence many ecosystem functions, such as soil stability and C and N cycling. However, longer-term effects of wildfire on BSC abundance, species richness, functional groups, and ecosystem functions after wildfire (i.e., BSC resilience) are still poorly understood. We sampled BSC lichen and bryophyte communities at four sites in Idaho, USA, within foothill steppe communities that included wildfires from 12 to 16 years old. We established six plots outside each burn perimeter and compared them with six plots of varying severity within each fire perimeter at each site. BSC cover was most strongly negatively impacted by wildfire at sites that had well-developed BSC communities in adjacent unburned plots. BSC species richness was estimated to be 65 % greater in unburned plots compared with burned plots, and fire effects did not vary among sites. In contrast, there was no evidence that vascular plant functional groups or fire severity (as measured by satellite metrics differenced normalized burn ratio (dNBR) or relativized differenced normalized burn ratio (RdNBR)) significantly affected longer-term BSC responses. Three large-statured BSC functional groups that may be important in controlling wind and water erosion (squamulose lichens, vagrant lichens, and tall turf mosses) exhibited a significant decrease in abundance in burned areas relative to adjacent unburned areas. The decreases in BSC cover and richness along with decreased abundance of several functional groups suggest that wildfire can negatively impact ecosystem function in these semiarid ecosystems for at least 1 to 2 decades. This is a concern given that increased fire frequency is predicted for the region due to exotic grass invasion and climate change.

Short summary
We evaluated soil crust communities 12–16 years after four wildfires in Idaho, USA, compared with adjacent unburned plots. We found that richness and abundance were lower in burned plots and that the cover of soil crusts was more strongly affected by wildfire at sites with well-developed soil crusts. Furthermore, we found that three large functional groups of lichens and mosses were associated with unburned sites and that fire severity was not related to post-fire soil crust communities.
Final-revised paper