Reports, Powell River Project
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Browsing Reports, Powell River Project by Author "Badgley, Brian D."
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- Characterizing Microbial Community Development in Reclaimed Mine SoilsBadgley, Brian D.; Sun, Shan (Virginia Tech. Powell River Project, 2014)A significant amount of the research to date at the Powell River Project (PRP) has been focused on reforestation, with the assumption that tree growth will ultimately lead to the re-establishment of a fully functioning forest ecosystem. Soil microorganisms are a critical component of this system because they mediate many of the ecosystem services for which forests are valued including carbon sequestration, soil formation, nutrient retention, watershed protection, and groundwater purification. We are characterizing the response of soil microbial communities to land reclamation approaches in the PRP to provide critical information about the restoration of the microbial component of the forest ecosystem. The objectives of this project are threefold: 1) characterize the recovery of soil microorganisms over time; 2) determine if alternate reclamation practices affect microbial diversity and community structure; and 3) compare restored microbial communities to un-mined forest soils to identify potential indicators that ‘healthy’ microbial communities are returning to reclaimed soils. We have identified a variety of reclamation plots within the PRP that represent a range of ages between 5 and 30 years to look at the effects of time. We have also sampled two other sets of to determine effects of reclamation practices: one where soils were amended with biosolids and another that was planted with pines as opposed to the standard hardwood mix. We are using genomic sequencing to fully characterize bacterial and fungal organisms present in soil samples from each plot to determine microbial diversity and community structure. Preliminary results suggest that bacterial communities recover quickly, becoming indistinguishable from communities in undisturbed soils within 10 to 30 years. In addition, certain taxa such as Bacteroidetes, Verrucomicrobia, and Gemmatimonadetes appear to respond to age since reforestation and may contain taxa that can be used to gauge restoration progress.
- Effects of Glyphosate Herbicide on Phytophthora cinnamomi and Mine Soil Microbial CommunitiesKlopf, Sara K.; Holliday, Jason A.; Badgley, Brian D. (Virginia Tech. Powell River Project, 2019)The American Chestnut (Castanea denata) was once the dominant hardwood species within the forests of the Appalachians and an important resource for people and wildlife. In the early 1900s, a fungal blight (Cryphonectria parasitica) was introduced from imported ‘Japanese Giant’ nursery trees that caused topkill of American chestnuts (Tallamy 2007). Trees infected with C. parasitica die back, then continually resprout from the roots. Since 1983, the American Chestnut Foundation has been conducting a backcross breeding program to produce hybrid trees resistant to the blight, and more recently, various research institutions have been working to develop transgenic varieties of American chestnut which express genes that may give the trees resistance to the blight. Additional pathogens, such as the fungus-like oomycete which causes root rot (Phytophthora cinnamomi), have furthered threatened C. dentata, and research of transgenic American chestnuts has included the identification of genes that may provide resistance to P. cinnamomi.
- The Role of Plant Diversity in Promoting Recovery of Soil Microbial Communities During Ecosystem Restoration on Reclaimed Mine LandsBadgley, Brian D.; Strahm, Brian D. (Virginia Tech. Powell River Project, 2017)Plant establishment is a key component of land reclamation and restoration, but ultimately full recovery of other beneficial ecosystem services that were provided prior to disturbance is desired for successful restoration. Many of these ecosystem services, primarily related to nutrient cycling and other biogeochemical processes, are regulated by microorganisms. However, the factors that promote the return of beneficial soil microorganisms – and the ecological functions they perform – to restored ecosystems are not well understood. Our previous work in the Powell River Project has discovered that the type of vegetation used to reforest reclaimed mine soils may not only control the resulting plant community, but also the trajectory of the soil microbial community and the processes they mediate related to important ecosystem services. In this work, we experimentally tested the hypothesis that carbon substrate diversity, provided by plant root exudates, is an important mechanism in shaping soil microbial communities as ecosystems recover. In a controlled greenhouse experiment, we analyzed microbial community structure and diversity of dissolved organic carbon substrates in experimental PRP soil mesocosms planted with one of five plant diversity treatments: chicory, clover, foxtail, rye, or an even mix of all four. Results indicate that plant species has significant effects on soil dissolved organic carbon substrate quantity and quality, as well as soil microbial community structure, with clover and chicory resulting in the most distinct changes. In addition, among the non-leguminous plant species, patterns of carbon substrate and microbial diversity tracked each other, suggesting an important interaction between the two.