Jech Sierra D, Day Natalie, Barger Nichole N, Antoninka Anita, Bowker Matthew A, Reed Sasha, Tucker Colin
Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO 80309, USA.
Colorado Water Science Center, U.S. Geological Survey, Grand Junction, CO 81506, USA.
Microorganisms. 2023 Oct 15;11(10):2570. doi: 10.3390/microorganisms11102570.
Land use practices and climate change have driven substantial soil degradation across global drylands, impacting ecosystem functions and human livelihoods. Biological soil crusts, a common feature of dryland ecosystems, are under extensive exploration for their potential to restore the stability and fertility of degraded soils through the development of inoculants. However, stressful abiotic conditions often result in the failure of inoculation-based restoration in the field and may hinder the long-term success of biocrust restoration efforts. Taking an assisted migration approach, we cultivated biocrust inocula sourced from multiple hot-adapted sites (Mojave and Sonoran Deserts) in an outdoor facility at a cool desert site (Colorado Plateau). In addition to cultivating inoculum from each site, we created an inoculum mixture of biocrust from the Mojave Desert, Sonoran Desert, and Colorado Plateau. We then applied two habitat amelioration treatments to the cultivation site (growth substrate and shading) to enhance soil stability and water availability and reduce UV stress. Using marker gene sequencing, we found that the cultivated mixed inoculum comprised both local- and hot-adapted cyanobacteria at the end of cultivation but had similar cyanobacterial richness as each unmixed inoculum. All cultivated inocula had more cyanobacterial 16S rRNA gene copies and higher cyanobacterial richness when cultivated with a growth substrate and shade. Our work shows that it is possible to field cultivate biocrust inocula sourced from different deserts, but that community composition shifts toward that of the cultivation site unless habitat amelioration is employed. Future assessments of the function of a mixed inoculum in restoration and its resilience in the face of abiotic stressors are needed to determine the relative benefit of assisted migration compared to the challenges and risks of this approach.
土地利用方式和气候变化已导致全球旱地出现大量土壤退化，影响生态系统功能和人类生计。生物土壤结皮是旱地生态系统的一个常见特征，人们正在广泛探索其通过开发接种剂来恢复退化土壤稳定性和肥力的潜力。然而，恶劣的非生物条件往往导致基于接种的田间恢复失败，并可能阻碍生物结皮恢复工作的长期成功。我们采用辅助迁移方法，在凉爽沙漠地区（科罗拉多高原）的户外设施中培养源自多个热适应地点（莫哈韦沙漠和索诺兰沙漠）的生物结皮接种物。除了培养每个地点的接种物外，我们还创建了一种由莫哈韦沙漠、索诺兰沙漠和科罗拉多高原的生物结皮组成的接种物混合物。然后，我们对培养地点应用了两种栖息地改善处理（生长基质和遮荫），以增强土壤稳定性和水分可用性，并减少紫外线胁迫。通过标记基因测序，我们发现培养的混合接种物在培养结束时包含本地适应和热适应的蓝细菌，但蓝细菌丰富度与每种未混合的接种物相似。当与生长基质和遮荫一起培养时，所有培养的接种物都有更多的蓝细菌16S rRNA基因拷贝和更高的蓝细菌丰富度。我们的工作表明，有可能在田间培养源自不同沙漠的生物结皮接种物，但除非采用栖息地改善措施，群落组成会向培养地点的群落组成转变。未来需要评估混合接种物在恢复中的功能及其面对非生物胁迫的恢复力，以确定辅助迁移相对于这种方法的挑战和风险的相对益处。
