Resistance, Resilience, and Recovery of Dryland Soil Bacterial Communities Across Multiple Disturbances.

Blaire Steven,Sasha C Reed,Cheryl R Kuske,Michala L Phillips,La Verne Gallegos-Graves,Jayne Belnap

doi:10.3389/fmicb.2021.648455

Abstract

Dryland ecosystems are sensitive to perturbations and generally slow to recover post disturbance. The microorganisms residing in dryland soils are especially important as they contribute to soil structure and nutrient cycling. Disturbance can have particularly strong effects on dryland soil structure and function, yet the natural resistance and recovery of the microbial components of dryland soils has not been well documented. In this study, the recovery of surface soil bacterial communities from multiple physical and environmental disturbances is assessed. Samples were collected from three field sites in the vicinity of Moab, UT, United States, 6 to 7 years after physical and climate disturbance manipulations had been terminated, allowing for the assessment of community recovery. Additionally, samples were collected in a transect that included three habitat patches: the canopy zone soils under the dominant shrubs, the interspace soils that are colonized by biological soil crusts, and edge soils at the plot borders. Field site and habitat patch were significant factors structuring the bacterial communities, illustrating that sites and habitats harbored unique soil microbiomes. Across the different sites and disturbance treatments, there was evidence of significant bacterial community recovery, as bacterial biomass and diversity were not significantly different than control plots. There was, however, a small number of 16S rRNA gene amplicon sequence variants that distinguished particular treatments, suggesting that legacy effects of the disturbances still remained. Taken together, these data suggest that dryland bacterial communities may possess a previously unappreciated potential to recover within years of the original disturbance.

Highlights

Soil microorganisms are central to many biogeochemical cycles, including those for carbon, nitrogen, and phosphorus
Similar dynamics are observed for the CV field site, with clear differences between the warming (W), precipitation (P), and warming and precipitation (W+P) datasets (Figure 2)
Across the experiment there were no significant differences in 16S rRNA gene copy numbers between field sites or manipulations, indicating that bacterial biomass was similar across filed site and manipulations

Summary

Introduction

Soil microorganisms are central to many biogeochemical cycles, including those for carbon, nitrogen, and phosphorus. The capacity of a community to recover from a disturbance is referred to as the community’s resilience (Baho et al, 2012). A community’s resilience defines the severity of population shifts in response to a disturbance and the time scales at which recovery can be expected to occur. Information on the resilience of soil microbial communities is severely lacking (García-García et al, 2019; Rath et al, 2019; Uritskiy et al, 2019). The authors posit that this either reflects that microbial communities have not been sampled with enough replication or duration to assess recovery, or that microbial populations have a low resilience to disturbance (Shade et al, 2012). There is considerable uncertainty regarding the resilience of microbial communities to the multitude of disturbances they face in a changing environment and under altered land use

Methods

Results

Conclusion