Inoculated biocrust cover and functions diverged over a gradient of soil textures and water availability

Authors: Young, Kristina; REED, SASHA - Us Geological Survey; MORTON, MICHAEL - Northern Arizona University; BOWKER, MATTHEW - Northern Arizona University

Submitted to: Restoration Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2024
Publication Date: 3/21/2024
Citation: Young, K.E., Reed, S.C., Morton, M., Bowker, M.A. 2024. Inoculated biocrust cover and functions diverged over a gradient of soil textures and water availability. Restoration Ecology. Article e14125. https://doi.org/10.1111/rec.14125.
DOI: https://doi.org/10.1111/rec.14125

Interpretive Summary: Restoring living things to drylands is a tough challenge because of the harsh conditions like limited water, diverse soil types, and extreme temperatures that make it hard for living things to grow. While we understand how these tough conditions can stop plants from growing, we know very little about how these conditions affect the growth of small soil organisms called biocrusts, which are important in dry areas. In our study, we tried something similar to planting seeds but instead used biocrust organisms. We changed their environment in different ways to see how different growing conditions affect their growth and their ability to provide important services. We found that by changing the type of soil and the amount of water, we could change the amount and types of biocrusts that grew. These biocrusts also had a small impact on the stability of soil and nitrogen capture from the air. This study is an important first steps in figuring out how to bring back these important biocrusts to drylands, similar to how we think about bringing back plants.

Technical Abstract: Restoring biological crust (biocrust) in disturbed drylands is challenging due to the difficult environmental conditions, such as limited soil moisture, low soil nutrients, and extreme temperatures, that impede growth. Understanding how the key components of biocrust—mosses, lichens, and cyanobacteria—react to different environmental factors informs the optimal timing, locations, and species composition for biocrust reintroduction, thereby increasing the likelihood of establishment. Here, we inoculated soils with a diverse range of biocrust organisms, analogous to seeding an area with diverse vascular plant seeds, and varied environmental conditions to observe how these changes influenced the development and functions of reintroduced biocrust. We found that by manipulating soil texture and time spent wet, we can change the proportional cover of biocrust within a restoration-like setting. Specifically, we found that 4'months after inoculation, finer textured soils that received more water become dominated by moss cover, while coarser textured soils with less water remained dominated by cyanobacteria cover, and the interactions between texture and time spent wet strongly influenced cover. We found biocrust morphological group cover had a small, but detectable, effect on ecosystem functions (soil stability and nitrogenase activity, a proxy for nitrogen fixation), but that environmental conditions had a stronger impact on the functions we measured. Manipulative experiments in controlled environments, like this one, can help elucidate the mechanisms underlying the establishment rate and patterns of biocrusts post-inoculation, and inform implementation of inoculations in the field.