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Cao J, Li B, Qi R, Liu T, Chen X, Gao B, Liu K, Baskin CC, Zhao Z. Negative impacts of human disturbances on the seed bank of subalpine forests are offset by climatic factors. Sci Total Environ 2022; 851:158249. [PMID: 36028043 DOI: 10.1016/j.scitotenv.2022.158249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 08/19/2022] [Accepted: 08/20/2022] [Indexed: 06/15/2023]
Abstract
Precipitation and temperature in the subalpine region have increased dramatically in recent decades due to global warming, and human disturbances have continued to impact the vegetation in the region. Seed bank plays an important role in population recovery, but there are few studies on the synergistic effects of human disturbances and climate change on seed bank. We analyzed the synergistic effects of human disturbances and climate change on seed bank samples from 20 sites in the subalpine coniferous forest region using grazing and logging as the disturbance intensity gradient and precipitation and temperature as climate variables. The species diversity of aboveground vegetation all changed significantly (p < 0.05) with precipitation, temperature and disturbance level, while the seed bank richness and density did not. Furthermore, the species composition of the seed bank varied significantly less than that of the aboveground vegetation at different levels of disturbance (p < 0.001). Thus, seed bank showed a strong buffering capacity against the risk of local extinction caused by environmental changes that shift the species composition and diversity of aboveground vegetation. In addition, soil and litter are important influences controlling seed bank density in subalpine forests, and the results of structural equation modelling suggest that both disturbance and climate change can indirectly regulate the seed bank by changing the physicochemical properties of soil and litter. We conclude that increases in precipitation and temperature driven by climate change can buffer the negative effects of disturbances on the seed bank.
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Affiliation(s)
- Jiahao Cao
- State Key Laboratory of Grassland Agro-ecosystems, College of Ecology, LanZhou University, Lanzhou 730070, China; Institute of Forestry Science of Bailongjiang in Gansu Province, Lanzhou 730046, China; Gansu Bailongjiang National Forest Ecosystem Research Station, Zhouqu 746300, China
| | - Bo Li
- Institute of Forestry Science of Bailongjiang in Gansu Province, Lanzhou 730046, China; Gansu Bailongjiang National Forest Ecosystem Research Station, Zhouqu 746300, China.
| | - Rui Qi
- Institute of Forestry Science of Bailongjiang in Gansu Province, Lanzhou 730046, China; Gansu Bailongjiang National Forest Ecosystem Research Station, Zhouqu 746300, China
| | - Ting Liu
- Institute of Forestry Science of Bailongjiang in Gansu Province, Lanzhou 730046, China; Gansu Bailongjiang National Forest Ecosystem Research Station, Zhouqu 746300, China
| | - Xuelong Chen
- Institute of Forestry Science of Bailongjiang in Gansu Province, Lanzhou 730046, China; Gansu Bailongjiang National Forest Ecosystem Research Station, Zhouqu 746300, China
| | - Benqiang Gao
- Institute of Forestry Science of Bailongjiang in Gansu Province, Lanzhou 730046, China; Gansu Bailongjiang National Forest Ecosystem Research Station, Zhouqu 746300, China
| | - Kun Liu
- State Key Laboratory of Grassland Agro-ecosystems, College of Ecology, LanZhou University, Lanzhou 730070, China
| | - Carol C Baskin
- Department of Biology, University of Kentucky, Lexington, USA; Department of Plant and Soil Sciences, University of Kentucky, Lexington, USA
| | - Zhigang Zhao
- State Key Laboratory of Grassland Agro-ecosystems, College of Ecology, LanZhou University, Lanzhou 730070, China.
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Miao Y, Heintz MB, Bell CH, Johnson NW, Polasko AL, Favero D, Mahendra S. Profiling microbial community structures and functions in bioremediation strategies for treating 1,4-dioxane-contaminated groundwater. J Hazard Mater 2021; 408:124457. [PMID: 33189472 DOI: 10.1016/j.jhazmat.2020.124457] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 09/28/2020] [Accepted: 10/30/2020] [Indexed: 06/11/2023]
Abstract
Microbial community compositions and functional profiles were analyzed in microcosms established using aquifer materials from a former automobile factory site, where 1,4-dioxane was identified as the primary contaminant of concern. Propane or oxygen biostimulation resulted in limited 1,4-dioxane degradation, which was markedly enhanced with the addition of nutrients, resulting in abundant Mycobacterium and Methyloversatilis taxa and high expressions of propane monooxygenase gene, prmA. In bioaugmented treatments, Pseudonocardia dioxanivorans CB1190 or Rhodococcus ruber ENV425 strains dominated immediately after augmentation and degraded 1,4-dioxane rapidly which was consistent with increased representation of xenobiotic and lipid metabolism-related functions. Although the bioaugmented microbes decreased due to insufficient growth substrates and microbial competition, they did continue to degrade 1,4-dioxane, presumably by indigenous propanotrophic and heterotrophic bacteria, inducing similar community structures across bioaugmentation conditions. In various treatments, functional redundancy acted as buffer capacity to ensure a stable microbiome, drove the restoration of the structure and microbial functions to original levels, and induced the decoupling between basic metabolic functions and taxonomy. The results of this study provided valuable information for design and decision-making for ex-situ bioreactors and in-situ bioremediation applications. A metagenomics-based understanding of the treatment process will enable efficient and accurate adjustments when encountering unexpected issues in bioremediation.
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Affiliation(s)
- Yu Miao
- Department of Civil and Environmental Engineering, University of California, Los Angeles, CA 90095, United States
| | - Monica B Heintz
- Arcadis North America, Highlands Ranch, CO 80129, United States
| | | | - Nicholas W Johnson
- Department of Civil and Environmental Engineering, University of California, Los Angeles, CA 90095, United States
| | - Alexandra LaPat Polasko
- Department of Civil and Environmental Engineering, University of California, Los Angeles, CA 90095, United States
| | - David Favero
- Revitalizing Auto Communities Environmental Response (RACER) Trust, Detroit, MI 48226, United States
| | - Shaily Mahendra
- Department of Civil and Environmental Engineering, University of California, Los Angeles, CA 90095, United States.
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