Source: UNIVERSITY OF NEW HAMPSHIRE submitted to NRP
LINKING SMALL MAMMALS AND MYCORRHIZAL FUNGI TO FOREST REGENERATION
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1019306
Grant No.
2019-67012-29656
Cumulative Award Amt.
$157,244.00
Proposal No.
2018-08136
Multistate No.
(N/A)
Project Start Date
May 15, 2019
Project End Date
May 14, 2022
Grant Year
2019
Program Code
[A7201]- AFRI Post Doctoral Fellowships
Recipient Organization
UNIVERSITY OF NEW HAMPSHIRE
51 COLLEGE RD SERVICE BLDG 107
DURHAM,NH 03824
Performing Department
Natural Resources and the Envi
Non Technical Summary
Animals are an integral component to forests, yet much remains unknown about how their functional role may contribute to the sustainable management of forests under anthropogenic stressors, invasive pests, and climate change. The goal of this project is to develop a mechanistic understanding of the role of small mammals (mice, voles, chipmunks) in mediating soil fungal diversity and the subsequent effects on forest regeneration following timber harvest. Mycorrhizal fungi are symbionts that colonize roots and assist trees with nutrient and water uptake. To aid in their dispersal, fungi produce fruiting bodies which small mammals consume, subsequently dispersing the spores across the forest through their scat. Thus, similar to pollinators, small mammals have the potential to mediate local fungal diversity which subsequently may affect tree establishment and growth. To assess these linkages, the proposed work will couple surveys of small mammals and tree seedlings in cleared and adjacent mature forest, with a greenhouse experiment. High-throughput sequencing will be used to characterize fungal communities in soil, mammal scat, and on tree root tips. This project will generate much needed empirical data on which mammal species best disperse fungi, the distance over which they disperse spores into cleared forest gaps, and how mammal mediated fungal spore dispersal impacts the mycorrhizal colonization, survival, and growth of tree seedlings. Ultimately, this work will have important implications for how animals contribute to the response of forests to disturbance, including regeneration following timber harvest, and will demonstrate the value of the mutualistic relationship between small mammals and mycorrhizal fungi for forest management. Specifically, forest managers may be able to increase seedling establishment and tree growth following timber harvests by maintaining habitat for small mammals critical for the dispersal of mycorrhizal fungi.
Animal Health Component
20%
Research Effort Categories
Basic
80%
Applied
20%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
12306991070100%
Knowledge Area
123 - Management and Sustainability of Forest Resources;

Subject Of Investigation
0699 - Trees, forests, and forest products, general;

Field Of Science
1070 - Ecology;
Goals / Objectives
I propose to develop a mechanistic understanding of the role of small mammals in mediating soil fungal diversity and its subsequent effect on forest regeneration following timber harvest.My specific objectives are to:1.) Identify which small mammals species are the primary dispersers of mycorrhizal fungi.2.) Quantify the relative contribution of wind and small mammals as dispersers of mycorrhizal spores into forest clear cuts.3.) Determine how mycorrhizal fungi in small mammal scat influences tree seedling survival, growth, and root colonization.
Project Methods
Methods: Project goals will be accomplished by coupling surveys of small mammals and seedlings incleared and adjacent mature forest, with a greenhouse experiment, and high-throughputsequencing to characterize fungal communities in soil, mammal scat, and on tree root tips. Thisresearch is novel because the interactions among small mammals, mycorrhizal fungi, and treeshave not previously been considered in relationship to forest management. As a result, I expectmy results will significantly advance our understanding of the mechanisms that promote forestregeneration. The project has three main components:To determine the small mammal species that are the primary dispersers of mycorrhizal fungi I will use live trapping transects to track the movement of small mammals within clear cuts and adjacent forest. Scat samples collected from the traps will be used to identify the fungi each mammal species consumes and the distances they can disperse spores from intact forest into clear cuts.To quantify the relative contribution of wind and small mammals as dispersers of mycorrhizal spores into forest clear cuts I will use passive spore traps to quantify the number andtypes of spores dispersed by the wind and how far into clear cuts they are moved. Comparison with mammal scat will determine whether the contribution of both dispersal sources to dispersal is complementary or redundant.I will use a greenhouse experiment to determine how mycorrhizal fungi in small mammal scat influences tree seedling survival, growth, and root colonization. In the greenhouse, I will deploy a series of treatments using small mammal scat to inoculate soil collected from clear-cuts. I will monitor seedling survival and growth, and compare root tip mycorrhizal colonization rates and fungal diversity between treatment seedlings and the roots of seedlings collected in the clear cut areas.Efforts: Results of this research will be disseminated to a wide variety of stake holders from the general public to forest managers. I will develop a workshop geared toward a general audience that will communicate the symbiotic link between forest health, small mammals, and mycorrhizal fungi. Additionally, because my research will be conducted at a USDA Forest Service funded Adaptive Silviculture for Climate Change (ASCC) site, I will be able to directly communicate my results with the local forest managers and scientists at both the annual on-site training sessions and off-site research network meetings. Results will also be disseminated to the scientific community through presentations at national conferences and peer-reviewed publications.Evaluation: I will use activities for each project component as milestones for each objective. Each objective is tied to findings that may inform forest management, and I will communicate with an advisory group so they can evaluate the potential impacts and seek their guidance on incorporating those findings in annual ASCC scheduled training sessions and other educational or extension outlets. I will evaluate the outreach component of this project through surveys administered to attendees of the interactive workshop. This project has the potential for at least three peer-reviewed publications that will be presented at national conferences. These deliverables and events will act as further markers of project milestones.

Progress 05/15/19 to 05/14/22

Outputs
Target Audience:Results on the role that small mammals have on dispersal of mycorrhizal fungi and forest regeneration were shared with three target audiences: (1) land managers and university-based research scientists involved with the Adaptive Silviculture for Climate Change project at Second College Grant through cooperators meetings, (2) scientists and foresters interested in forest ecology, mycology, and mammalogy through (i) peer reviewed publications, (ii) scientific conference presentations, (iii) invited seminars at academic institutions (iv) and summary article geared toward foresters and land managers and (3) members of the general public interested in mycology and truffles through presentations. Changes/Problems:We experienced challenges implementing our greenhouse experiments including issues maintaining proper soil moisture and high mortality of seedlings. An additional experiment was set up to rectify issues but results were ambiguous. What opportunities for training and professional development has the project provided?Postdoctoral researcher, Ryan Stephens, participated in multiple weekly research team meetings providing him with a broad understanding of soil science, fungal ecology, and mammalogy while expanding his network of researchers across campus. To increase networking opportunities he attended two working group meetings at Dartmouth College with scientists conducting research at Second College Grant and presented research results from objective one at the Ecological Society of America meeting in 2020 and the American Society of Mammalogists meeting in 2021. He also was trained in DNA extractions, PCR, and bioinformatics. Postdoctoral Researcher Ryan Stephens trained one graduate student and one undergraduate student in data analysis and microscopy associated with aspects of objective 2. How have the results been disseminated to communities of interest?Results were presented at three scientific conferences, the Ecological Society of America virtual meeting in 2020, American Society of Mammalogists virtual meeting in 2021, and the British Mycological Society Autumn Open Meeting in 2021. Results were also presented to students and scientists at four academic institutions during the duration of this project. Additionally, results of small mammal spore dispersal capacity and greenhouse experiment were presented to foresters and scientists involved with the Adaptive Silviculture for Climate Change (ASCC) at Second College Grant during a cooperators meeting in February 2020 and 2021 at Dartmouth College, New Hampshire. Findings of how small mammals contribute to fungal dispersal following timber harvest were shared with foresters at a meeting in 2021 and 2022. Results were also shared with the general public during a presentation to the North American Truffling Society and the Harris Center for Conservation Education. Results on the influence of forest harvesting on mushroom production were shared with university-based research scientists and students through a poster presentation at the UNH Graduate Student Research Conference. Additionally, preliminary results of the influence of small mammals on seed removal and seedling establishment were presented to university-based research scientists and students through poster presentations at the UNH Undergraduate Student Research Conference. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1: Using field data collected at Second College Grant in northern New Hampshire, we examined the functional, temporal, and spatial components of mycorrhizal fungal spore dispersal by small mammals following timber harvest. We tracked the interactions of seven small mammal species and 34 fungal taxa over a two-year period directly following harvests. Additionally, we measured species-specific microhabitat associations of small mammals to determine where species deposited spores. We found that small mammal species were complementary in the functional type of fungi that they dispersed, with some species primarily dispersing arbuscular mycorrhizal (AM) fungal spores and others dispersing ectomycorrhizal (ECM) fungal spores. However, more species consumed AM fungi, making dispersal of AM spores more robust to changes in the small mammal community compared to ECM spores, which were primarily dispersed by two small mammal species. Small mammal species varied from having no microhabitat associations to associating with a variety of different conditions, indicating that species play different roles from broadcasting spores widely to depositing spores in discrete locations. By preserving and enhancing microhabitat characteristics that are associated with small mammals in harvested areas, particularly for species that disperse ECM fungi, forest managers can help maintain dispersal of mycorrhizal fungi by small mammals. This work was published in Functional Ecology in 2021. Objective 2: Using paired sampling from aerial spore traps and scat from small mammal sampling we compared the functional types and community composition of fungi dispersed by wind and small mammals. We found marked differences in fungal richness and community composition between the two dispersal modes. Wind-dispersed fungi were dominated by wood saprotrophs, litter saprotrophs, and plant pathogens, whereas mammal-dispersed fungi were dominated by mycorrhizal, soil saprotrophs, and unspecified saprotrophs. These findings suggest mammals may be more important than wind at dispersing mycorrhizal fungi directly following timber harvests. This work was recently submitted for publication at the journal Ecology. In order to understand fungal spore dispersal, it is first important to understand fungal sporocarp fruiting. Using mushroom survey data collected during the summer of 2019 we determined differences in fungal fruiting patterns in forests and patch cuts. Results of this study were published in Canadian Journal of Forest Research in 2022. Objective 3: We conducted a six-month greenhouse experiment with spruce seedlings grown in field collected soils and inoculated with small mammal scat. A total of 86 seedlings were harvested and analyzed on a dissecting scope to determine the percentage of roots colonized by mycorrhizal fungi. Roots were also sequenced and analyzed for ectomycorrhizal fungal community composition. Although seedlings inoculated with small mammal scat were significantly larger, we found no significant differences in community composition between inoculated seedlings and control seedlings (sterilized scat added). In order to determine the potential capacity of small mammals to inoculate arbuscular mycorrhizal associated plants, an additional greenhouse experiment was initiated during the fall of 2020 that used red maple and sugar maple seedlings grown in mycorrhizal free potting soil and inoculated with small mammal scat. Poor survival of sugar maple seedlings and the addition of fertilizer to red maple seedlings limited the generality of this experiment. Although we experienced challenges while conducting both greenhouse experiments, knowledge gained during these projects is currently being applied to a greenhouse experiment looking at the influence of secondary dispersal of spores by carnivores on colonization and growth of tree seedlings. Small mammals also influence seedling establishment directly through the consumption and removal of seeds. We analyzed sugar maple seed removal and seedling recruitment data collected during the summer of 2020 to determine the role that granivory by small mammals play in limiting tree recruitment. We found that mammals remove around 40% of viable sugar maple seedlings and this results in reduced sugar maple establishment, particularly in harvested areas. This highlights the importance of maintaining advanced regeneration of sugar maple seedlings during timber harvesting as sugar maple recruitment from seed may be limited due to granivory from small mammals. A manuscript detailing these findings is in preparation and will be submitted shortly to Canadian Journal of Forest Research.

Publications

  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Stephens, R. B., A. P. Ouimette, E. A. Hobbie, and R. J. Rowe. 2022. Reevaluating trophic discrimination factors (d13C and d15N) for diet reconstruction. Ecological Monographs 92:e1525.
  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Borgmann-Winter, B. W., R. B. Stephens, A. W. DAmato, S. D. Frey, and R. J. Rowe. 2022. Effects of timber harvest on epigeous fungal fruiting patterns and community structure in a northern hardwood ecosystem. Canadian Journal of Forest Research 52:51-58.
  • Type: Other Status: Published Year Published: 2021 Citation: Borgmann-Winter, B. W., R. B. Stephens, S. D. Frey, and R. J. Rowe. 2021. Linking mycorrhizal fungi and small mammals to forest regeneration following timber harvesting. New England Society of American Foresters News Quarterly 82:4-7.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Stephens, R. B., S. D. Frey, A. W. DAmato, and R. J. Rowe. 2021. Functional, temporal, and spatial complementarity in mammal-fungal spore networks enhances mycorrhizal dispersal following forest harvesting. Functional Ecology 35:2072-2083.
  • Type: Journal Articles Status: Submitted Year Published: 2022 Citation: Borgmann-Winter, B. W., R. B. Stephens, M. A. Anthony, S. D. Frey, A. W. DAmato, and R. J. Rowe. submitted. Wind and small mammals are complementary fungal dispersers.
  • Type: Journal Articles Status: Other Year Published: 2022 Citation: Stephens, R. B., R. B. Parker, A. W. DAmato, B. W. Borgmann-Winter, and R. J. Rowe. in prep. Seed predation and distance from forest reduce sugar maple recruitment following forest harvesting.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Stephens, R. B. 2022. Truffles, small mammals, and healthy forests. Harris Center for Conservation Education talk. Hancock, NH (virtual)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Stephens, R. B. 2022. Mammals, truffles, and trees: linking above- and below-ground interactions. Department of Biology Seminar Series, University of Minnesota, Duluth, MN
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Stephens, R. B. 2022. Mammals, truffles, and forest regeneration: linking above- and below-ground trophic interactions. Department of Biology Seminar, Southeast Missouri State University, Cape Girardeau, MO
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Stephens, R. B. 2022. Mammals, truffles, and forest regeneration: linking above- and below-ground trophic interactions. School of Natural Resources and Environment Seminar, Lake Superior State University, Sault Ste. Marie, MI
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Stephens, R. B. 2022. The importance of small mammals and mycorrhizal fungi in forest management. Granite State Division of the Society of American Foresters Meeting, NH (virtual)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Stephens, R. B., A. W. DAmato, S. D. Frey, and R. J. Rowe. 2021. Small mammals, truffles, and forest regeneration. 30th Annual Coos County Forester Mud Season Breakfast. Errol, NH.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Stephens, R. B. 2021. Truffles, small mammals, and trees: linking above- and below-ground interactions. British Mycological Society Autumn Open Meeting, London, England (virtual)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Stephens, R. B. 2021. Small mammals, truffles, and forest regeneration. North American Truffling Society, Corvallis, OR (virtual)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Stephens, R. B. 2020. Small mammals, truffles, and forest regeneration: linking above- and below-ground multitrophic interactions. Department of Biology Seminar Series, New Mexico State University, NM (virtual)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Stephens, R. B., S. D. Frey, A. W. DAmato, and R. J. Rowe. 2021. Functional, temporal, and spatial complementarity in mammal-fungal spore networks enhances mycorrhizal dispersal following forest harvesting. 100th Annual Meeting of the American Society of Mammalogists, Online. (talk)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Stephens, R. B., R. J. Rowe, and S. D. Frey. 2020. Temporal, functional, and spatial complementarity in mammal-fungal spore networks enhances mycorrhizal dispersal following clear-cuts. 105th Meeting of the Ecological Society of America, Online. (talk)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Borgmann-Winter, B. W., R. B. Stephens, A. W. DAmato, S. D. Frey, and R. J. Rowe. 2021. Timber harvest affects mushroom fruiting and community structure in a northern hardwood ecosystem. UNH Graduate Research Conference. (poster)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Parker, R. B., R. B. Stephens, and R. J. Rowe. 2021. Effects of small mammal seed predation on seedling establishment in northern New Hampshire. UNH Undergraduate Research Conference. (poster)


Progress 05/15/20 to 05/14/21

Outputs
Target Audience:Results on the role that small mammal have on dispersal of mycorrhizal fungi and forest regeneration were shared with three target audiences: (1) land managers and university-based research scientists involved with the Adaptive Silviculture for Climate Change project at Second College Grant through a cooperators meeting, (2) scientists interested in ecology at the Ecological Society of America conference, and (3) members of the general public interested in mycology and truffles. Changes/Problems:Restrictions to campus lab facilities at the onset of COVID-19 delayed the initiation of the genetic sequencing, which is now complete. What opportunities for training and professional development has the project provided?Postdoctoral researcher, Ryan Stephens, participated in multiple weekly research team meetings providing him with a broad understanding of soil science, fungal ecology, and mammalogy while expanding his network of researchers across campus. To increase networking opportunities he attended a working group meeting at Dartmouth College with scientists conducting research at Second College Grant and presented research results from objective one at the Ecological Society of America virtual meeting. He also was trained in DNA extractions, PCR, and bioinformatics. In this project year, Postdoctoral Researcher Ryan Stephens trained one graduate student and one undergraduate student in data analysis and microscopy associated with aspects of objective 2. How have the results been disseminated to communities of interest?Results of small mammal species dispersing mycorrhizal fungi were presented at the Ecological Society of America virtual meeting to other scientists interested in forest ecology. Additionally, results of small mammal spore dispersal capacity and preliminary results from a greenhouse experiment were presented to foresters and scientists involved with the Adaptive Silviculture for Climate Change (ASCC) at Second College Grant during a cooperators meeting on February 25, 2020 at Dartmouth College, New Hampshire. Results were also shared during a presentation to the North American Truffling society, a group composed of scientists and members of the general public interested in mycology and truffles. Results of the influence of forest harvesting on mushroom production were shared with university-based research scientists and students through poster presentations at the UNH Graduate Student Research Conference. Additionally, preliminary results of the influence of small mammals on seed removal and seedling establishment were presented to university-based research scientists and students through poster presentations at the UNH Undergraduate Student Research Conference. What do you plan to do during the next reporting period to accomplish the goals?Results from objective one (which small mammal species are the best dispersers of mycorrhizal fungal spores) will be presented at the American Society of Mammalogists conference in June of 2021. During the next year, analyses addressing objective two (relative role of wind and small mammals at dispersing fungi) will be completed and a manuscript drafted and submitted to a scientific journal. Additionally, analyses will be completed for objective three (addressing the role of small mammal dispersed mycorrhizal fungi at colonizing plants) and at least one manuscript drafted. Additionally, as part of our overarching goal of determining the role that small mammals play during forest regeneration following timber harvest, we will analyze sugar maple seed removal and seedling recruitment data collected during the summer of 2020 to determine the role that small mammals play in limiting tree recruitment by granivory.

Impacts
What was accomplished under these goals? Objective 1: In a manuscript currently in revision in Functional Ecology we report on our key findings. Using field data collected at Second College Grant in northern New Hampshire, we examined the functional, temporal, and spatial components of mycorrhizal fungal spore dispersal by small mammals following timber harvest. We tracked the interactions of seven small mammal species and 34 fungal taxa over a two-year period directly following harvests. Additionally, we measured species-specific microhabitat associations of small mammals to determine where species deposited spores. We found that small mammal species were complementary in the functional type of fungi that they dispersed, with some species primarily dispersing AM fungal spores and others dispersing ECM fungal spores. However, more species consumed AM fungi, making dispersal of AM spores more robust to changes in the small mammal community compared to ECM spores, which were primarily dispersed by two small mammal species. Small mammal species varied from having no microhabitat associations to associating with a variety of different conditions, indicating that species play different roles from broadcasting spores widely to depositing spores in discrete locations. By preserving and enhancing microhabitat characteristics that are associated with small mammals in harvested areas, particularly for species that disperse ECM fungi, forest managers can help maintain dispersal of mycorrhizal fungi by small mammals. Objective 2: We have sequenced fungal DNA from areal spore traps and small mammal scat samples collected at Second College Grant collected during the summer of 2019. Additionally, we have begun microscopy on spore traps to complement microscopy of mammal scat, which was previously conducted as part of objective 1. In order to understand fungal spore dispersal it is first important to understand fungal sporocarp fruiting. Using mushroom survey data collected during the summer of 2019 we determined differences in fungal fruiting patterns in forests and patch cuts. Results of this study are currently in revision in Canadian Journal of Forest Research. Objective 3: As part of a greenhouse experiment, red spruce root samples from seedlings inoculated with small mammal scat were sequenced and analyzed for ectomycorrhizal fungal community composition. In order to determine the potential capacity of small mammals to inoculate arbuscular mycorrhizal associated plants, an additional greenhouse experiment was initiated during the fall of 2020 that used red maple and sugar maple seedlings grown in mycorrhizal free potting soil and inoculated with small mammal scat. Maple seedlings were grown for 6 months and harvested. Roots from these seedlings will be analyzed using microscopy and sequencing.

Publications

  • Type: Journal Articles Status: Under Review Year Published: 2021 Citation: Stephens, R. B., S. D. Frey, A. W. DAmato, and R. J. Rowe. in revision. Functional, temporal, and spatial complementarity in mammal-fungal spore networks enhances mycorrhizal dispersal following forest harvesting. Functional Ecology
  • Type: Journal Articles Status: Under Review Year Published: 2021 Citation: Borgmann-Winter, B. W., R. B. Stephens, A. W. DAmato, S. D. Frey, and R. J. Rowe. in revision. Effects of timber harvest on epigeous fungal fruiting patterns and community structure in a northern hardwood ecosystem. Canadian Journal of Forest Research
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Stephens, R. B., R. J. Rowe, and S. D. Frey. 2020. Temporal, functional, and spatial complementarity in mammal-fungal spore networks enhances mycorrhizal dispersal following clear-cuts. 105th Meeting of the Ecological Society of America, Online. (talk)
  • Type: Other Status: Published Year Published: 2021 Citation: Stephens, R. B. Small mammals, truffles, and forest regeneration. Seminar for the North American Truffling Society, Corvallis, OR, Online. (talk)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Borgmann-Winter, B. W., R. B. Stephens, A. W. DAmato, S. D. Frey, and R. J. Rowe. 2021. Timber harvest affects mushroom fruiting and community structure in a northern hardwood ecosystem. UNH Graduate Research Conference. (poster)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Parker, R. B., R. B. Stephens, and R. J. Rowe Effects of small mammal seed predation on seedling establishment in northern New Hampshire. UNH Undergraduate Research Conference. (poster)


Progress 05/15/19 to 05/14/20

Outputs
Target Audience:Preliminary results on the role that small mammal have on dispersal of mycorrhizal fungi and forest regeneration were shared with three target audiences: (1) foresters and scientists involved with the Adaptive Silviculture for Climate Change (ASCC) project at Second College Grant, (2) regional land managers, and (3) university-based research scientists, including graduate and undergraduate students. Changes/Problems:Restrictions to laboratory facilities due to Covid-19 during the spring of 2020 have delayed genetic analysis of both root tips from the greenhouse experiment and aerial spore traps. These activities will resume once university facilities reopen. Covid-19 restrictions also lead to the cancellation of a presentation to members of the New England Society of American Forests at their spring meeting in May. If possible, this presentation will occur during the spring of 2021. Low germination of sugar maple seeds precluded use of this tree species in the greenhouse experiment conducted in 2019. In order to determine the potential capacity of small mammals to inoculate arbuscular mycorrhizal associated plants, an additional greenhouse experiment is planned for the summer and fall of 2020 that uses red maple and sugar maple seeds grown in mycorrhizal free potting soil and inoculated with small mammal scat. This amended experiment will help demonstrate how arbuscular mycorrhizal spores dispersed by small mammals might influence the growth and colonization of seedlings. What opportunities for training and professional development has the project provided?Postdoctoral researcher, Ryan Stephens, participated in multiple weekly research team meetings providing him with a broad understanding of soil science, fungal ecology, and mammalogy while expanding his network of researchers across campus. To help foster professional development, he attended a workshop on career funding opportunities. Additionally, to increase networking opportunities he attended a working group meeting at Dartmouth College with scientists conducting research at Second College Grant. In this project year, Postdoctoral Researcher Ryan Stephens trained four undergraduate students. Two were trained in field methods including small mammal trapping and habitat surveys. One of these students was mentored on an independent research project relating microhabitat variables in clearcuts to use by small mammal species. Additionally, two undergraduates were trained in lab techniques, one in fungal spore microscopy and the other in sample preparation and weighing. How have the results been disseminated to communities of interest?Preliminary results of small mammal spore dispersal capacity and the greenhouse experiment were presented to foresters and scientists involved with the Adaptive Silviculture for Climate Change (ASCC) at Second College Grant during a cooperators meeting on February 11, 2020 at Dartmouth College, New Hampshire. An article about the research was posted on the Adaptive Silviculture for Climate Change website and is easily accessible by forests, scientists, and the general public (https://www.adaptivesilviculture.org/news/small-mammals-mycorrhizal-fungi-and-forest-regeneration). What do you plan to do during the next reporting period to accomplish the goals?During the next year, a manuscript addressing objective one (which small mammal species are the best dispersers of mycorrhizal fungal spores) will be drafted and submitted to a scientific journal. Results from this study will also be presented at the Ecological Society of America conference in August of 2020. Molecular analyses will be completed on scat samples and from aerial spore trap extractions. These will be used to determine how mammal spore dispersal compares to wind spore dispersal. Additional field work on small mammals will occur during the summer of 2020 to increase sample size for home range analyses which will be used to determine the spatial extent to which small mammal species disperse spores. Molecular analyses will also be performed on root tips from the greenhouse experiment to determine mycorrhizal communities of roots that have been inoculated with small mammal scat.

Impacts
What was accomplished under these goals? Objective 1: All indexing of small mammal abundance data, along with scat collection, was completed during the summer of 2019. Microscopy of small mammal scat, used to determine fungal spore loads, was completed for 440 scat samples collected during the summers of 2018 and 2019. Field measurements of vegetative structure were also collected during the summer of 2019 at 672 sites; these will be linked to small mammal site occurrence to determine the locations where small mammals are depositing fungal spores. Objective 2: Funnel traps (n =72), used to collect aerially dispersed spores, were established and collected in July and August of 2019 for a total of 144 samples. Spores were extracted onto filter paper and frozen for genetic and microscopic analysis. Objective 3: During the summer and fall of 2019, a six month greenhouse experiment with spruce seedlings grown in field collected soils and inoculated with small mammal scat was completed. A total of 86 seedlings were harvested and analyzed on a dissecting scope to determine the percentage of roots colonized by mycorrhizal fungi.

Publications