Recipient Organization
LOUISIANA TECH UNIVERSITY
(N/A)
RUSTON,LA 71272
Performing Department
Forestry
Non Technical Summary
Approach:Modern forests are generally significantly altered from their original condition, still their "health" matters and will dictate whether forests persist and function for future generations, providing timber, sustaining wildlife, sequestering carbon, and performing other ecological services (Sugden et al. 2007). Humans have introduced new species, including fungal pathogens of trees and altered forests such that managing with native pathogens has lead to new emerging diseases. This project will begin by evaluating the three kinds of forest types in Louisiana: uplands, lowlands, and maritime forests for fungi that fall into three major groups and contain most forest plant pathogens the: Ascomycota, Basidiomycota, and Oomycota phyla. I am pursuing the overall goal with three aims composed of several smaller studies done across habitat types and evaluating an array of fungal species. The goal of the project is to improve our understanding of forest health in Louisiana by examining, evaluating, and managing the fungal assemblages present and with and without health issues. While forests have evolved while experiencing disturbances such as drought, insect and disease outbreaks, and fire forests increasingly must also cope with the human-related intensification of stressors that affect forest condition (Trumbore et al. 2015), including those from introduction of invasive species pathogens and native pathogens emerging to cause more severe forest health problems. The projects first aim (to improve the identification of species attributed as the causes of decline/disease and evaluate fungal diversity in the state) will influence the other two aims, as these will all require the proper identification of fungal species found in Louisiana forests. The first aim will use current molecular tools, physiological tests, and phenotypic evaluations to discern and catalog a large number of the fungal species across the state. This will result in a catalog of the fungal macroflora species, as well as microflora, and will likely also include several new species to science. The studies will be done over the course of several years to properly gather information on fungi that have an ephemeral, cyclic nature and to provide a more comprehensive account on fungal diversity, and fungal succession. The second aim will be to increase knowledge of the ecology of the fungal players in Louisiana forests as it relates to health concerns at the tree level and the forest level by examining the mechanisms of potentially pathogenic relationships. Observations using fleets of drones (already available in the forestry program at LA Tech) of naturally occurring forest conditions will be done and will lead to improvements in detecting tree and forest mortality. Forest health will be defined as one that is both sustainable and productive after considering the size structures of forests to develop quantitative ecological concepts of forest health (Edmonds et al. 2000; Rubin et al. 2006; Castello and Teale 2011). A series of ecological experiments will be conducted, utilizing fungal species that play important roles in forest health- be it antagonistic or mutualistic ones and identified in Louisiana within the first aim. These experiments will be conducted as focused research on the underlying processes under controlled environmental conditions in lab facilities and greenhouses at Louisiana Tech University. The second aim will also help to determine the identity of potentially dangerous thresholds of forest health decline/disease by testing and modeling what those levels might be, based on what is found and the mechanisms of the relationship. Hypothetical thresholds will be set and modeled to test potentially dangerous levels of decline, if no serious decline is observed over the course of the study, and will be based on the actual species found, and ones of concern as invasive. The last aim will be to establish best management practices to help avoid introduction and movement of key pathogenic fungal species correlated with disease outbreaks and poor forest health. Ultimately, this will lead to the development of corresponding protocols for improved site selection and practices. This third aim will build off of information gleaned fulfilling the first two aims and will provide solutions to avoid introduction and movement of important pathogens that interrupt management goals and that are the cause of disease outbreaks. The project overall will provide background information that will help land managers choose better or improve sites to meet their own goals and suggest ways to improve practices.
Animal Health Component
70%
Research Effort Categories
Basic
30%
Applied
70%
Developmental
(N/A)
Goals / Objectives
Fungi drive forest health and decline but remain largely unexamined within Louisiana's forest ecosystems with varying physical terrain and humid-subtropical climate. The great fungal diversity of Louisiana complements and exceeds the diverse vegetation, and as the fungal flora has evolved an array of lifestyles, forms, and colors to align with their function and usefulness, they may also now outnumber plants 6:1. Fungi play major beneficial roles in the forest ecosystem and function by acting as decomposers, degrading the most complex chemical structures on earth (cellulose and lignin), providing nutrients and water to trees through mycorrhizal networks, and protein-rich fruiting bodies for animals. Fungi also act as pathogens, which can destroy forest products but serve to open forest canopies and create wildlife habitats. Regarding ecosystem function, fungi will have helped to shape and influence the forest communities of the world, including those found across the Atlantic-Gulf Coastal Plain region, which encompasses the state. The destruction of forests and forest products by fungi will be much easier to handle, expect, and understand with baseline information on the players already found within the state. The goal is to improve our understanding of forest health in Louisiana by examining, evaluating, and managing the fungal assemblages. Meeting this goal will be accomplished with three major aims, (1) to improve the identification of species attributed as the causes of decline / disease and evaluate fungal diversity in the state, (2) determine the parameters of the mechanistic relationship (host to fungi) as it relates to health concerns, and with that knowledge (3) develop best management practices to help avoid introduction and movement of key pathogenic fungal species correlated with forest disease outbreaks and poor forest health, and corresponding protocols for improved site selection and practices. As a result of completing this project, I expect to provide valuable insight into the role of fungi in forest health in Louisiana and also provide practical guidance for those dealing with forest health concerns.
Project Methods
AIM 1Title: Collecting and describing fungal species assemblagesObjectives:1) To collect, examine, identify, and compare the fungal species assemblages in Louisiana forests.Procedures:This project can be conducted in cooperation with other organizations such as the Forest Service, other universities in the area, and industry. This support will allow health studies previously installed to be accessed and compiled on an array of sites, increasing the breadth of those results.Cataloging fungal species- An integrated set of sampling protocols already established will be used for the first time in Louisiana. To catalog macrofungi, opportunistic sampling, sampling of fixed-size plots, and sampling of a fixed number of downed logs will be used as well as microplot sampling for Ascomycota species (Mueller et al. 2004). Additionally, Oomycotas sampling of Pythium and Phytophthora will be completed (Sims et al. 2014) and Halophytophthora from maritime ecosystems (Leano et al. 2000). To capture as much diversity as possible sampling will occur 3 x per year (late spring/early summer, fall, winter) for three years because particular species may fruit at different seasons across geographic distances or along ecological gradients (Ohenoja 1993; Lodge et al. 2004; O'Hanlon and Harrington 2012; Rudolph et al. 2018). Also, this will allow for seasonal variation in the presence of sporocarps, which can be enormous (Lodge et al. 2004). All fungi discernible with the naked eye on plant material from the ground to two meters height will be recorded (Lodge et al. 2004), e.g., saprobes on plant material, parasites on living plants, ectomycorrhizal fungi, as well as fungus-like organisms in Myxomycota, and Oomycota. Zygomycota species and fungal succession will be evaluated, according to Richardson (2002). Plants and fungi will be collected for identification if necessary, and standardized molecular identification used (White et al. 1990). Ambient temperature and relative humidity in the study will be continuously monitored with Hobo data loggers at 6-hour intervals. Daily precipitation data will be obtained from the nearest weather station to each study area.AIM 2Title: Determine the parameters of forest health concernsObjectives:1. Examine and map tree mortality and canopy structure using drone fleets to improve understanding and better describe the health differential of 'healthy' and 'unhealthy' forests and trees considering human, climatic, and biotic drivers.2. Evaluate the parameters associated with decline/disease and presence of pathogens, including the role of fungi in the formation of canopy openings, tree competition, and canopy structure.3. Conduct pathogenicity tests on species correlated with disease outbreaks.Procedures:Examining tree health-We will measure the diameter and height of trees in plots, and document canopy structure from ground and drone observations once a year for three years during lat summer. Trees will be rated based on canopy dieback, early senescence, other foliar symptoms, and bole symptoms using on the ground visual and remote sensing data (Stone and Mohammed 2017). The bases of trees will be examined for root disease. Overall trees will be examined considering human, climatic and biotic drivers (Trumbore et al. 2015) Plots will be rated based on recent mortality levels of each tree species. We will use current statistical techniques to conduct analyses as accurate as possible. Initial results will guide continued sampling (influencing the fungal diversity sampling) across seasons and based on the annual variation. We will be able to make selections of areas undergoing potentially increasing decline or mortality. Following this we will assess resulting levels and change in dieback and mortality across tree populations, forests, and ecosystems; and determine how changes in mortality and dieback are related to fungal species from the diversity surveys. Any additional sampling that is necessary for identifying possible causal agents will be included, and the role of fungi in the formation of canopy openings, tree competition, and canopy structure will be evaluated. Fungi collected will be used to conduct pathogenicity tests to complete Koch's postulates, where feasible field inoculations will be performed. Greenhouse tests will be conducted to control for as many factors as possible. As appropriate pathogens will be inoculated using a 6mm diameter agar disc containing mycelium according to Navarro (et al. 2015). Severity will be rated for each plant on the 1-6 ordinal scale following inoculation and incubation, to evaluate canopy (Madden et al. 2011) and diseased roots (Krause et al. 2001; Sánchez et al. 2002; Sánchez et al. 2005; Madden et al. 2011; Serrano et al. 2012). For stem canker assessment, the lesion area will be measured by lightly scraping the outer bark to observe the inner bark and cambium for necrosis and dead tissue. The symptomatic area (length x width) will then be measured to the nearest mm in each direction. Following all measurements, re-isolation of the pathogen will be performed from symptomatic tissue near the outer edges if no obvious signs (visible manifestations of the pathogen itself) are apparent, and identification of each obtained isolate will be made to the species level. All statistical analyses will be done in the R computing environment (R Core Team 2019), and effects will be evaluated at the 95% confidence level. Different models systems will be used to handle the distinct types of response variables in each test.AIM 3Title: Best management practices to improve future forest healthObjectives:Develop best management practices to help avoid introduction and movement of key pathogenic fungal species correlated with forest disease outbreaks and decline.Develop corresponding protocols for improved site selection and practices.Procedures: For planted and managed landscapes and agencies in need, develop best management practices to help avoid introduction and movement of key pathogenic fungal species correlated with forest disease outbreaks and forests in decline (Sims et al. 2016). This will include developing corresponding protocols for improved site selection and practices. A "big picture" approach will be used to create a realistic and logistically feasible approach as they relate to risk priorities for any involved agencies to develop best management practices and to help avoid introduction and movement of key pathogenic fungal species. A review of any existing BMPs can be done to use as baseline documents and then build and improve from there based on the condition of existing sites, needs and priorities. Identification of pathogens and potential vectors will be made, and correlated risk analyses will be done. Fieldwork best management practices including weed control, revegetation, watering, seed collection, and infrastructure (trails, roads, and construction) and maintenance as appropriate will be taken into account, developed and modified as necessary. Procedures for equipment and materials movement will also be taken into account, developed, and modified as necessary. Sampling and monitoring protocols will be outlined. Based on existing knowledge and information gleaned, develop corresponding protocols for improved site selection and practice. These will be modified and adapted to manage for the pathogens found, associated hosts, and landscape and ecosystem characteristics.