Increasing success of pitch pine restoration in the Albany Pine Bush Preserve using ectomycorrhizal fungi
Taylor R. Patterson
SUNY College of Environmental Science and Forestry
Final Report to the Edna Bailey Sussman Foundation
2016
Background
The Albany Pine Bush Preserve (APBP) is a fragmented system of 3,200 acres of protected pine barrens located between the cities of Schenectady and Albany, New York. It is situated among urban development and bisected by numerous roadways including interstate highways. It is unique in being one of the largest inland pine barrens in the world. Pitch pine barrens are globally limited and the APBP supports the federally endangered Karner Blue Butterfly as well as more than 50 animal and plant species classified as rare or of concern federally and by the state of New York. The unique ecosystem is also a popular outdoor recreation site for the public.
Urban development and fire suppression in the past have negatively affected the native plant communities and enabled invasion by exotic locust trees. Restoration efforts in the APBP have focused on reintroducing periodic fires, removing invasive locusts, and reestablishing pitch pine. Restoration of pitch pines by forest managers has had varied success in different areas of the pine bush, but the factors affecting restoration failures are not clear. My goal is to understand how soil fungi and below-ground interactions may be influencing restoration success, in hopes of providing a tool for restoration at the APBP.
Most plant life depends on symbiotic fungi for survival. The fungi provide nutrients and water to the plants in exchange for plant sugars. Pitch pines and the invasive locust both require fungal partners, but the specific fungi they associate with are mutually exclusive. It is likely that success of pitch pine growth in areas where locusts have been removed or areas far from existing stands is hampered by the lack of appropriate fungal partners. Reintroduction of compatible fungi may improve the success of reestablishing the native plant communities.
The rationale of this approach comes from the work of my advisor, Dr. Tom Horton, and his previous students and collaborators. They have found strong influences of mycorrhizal partners enabling invasion or establishment of pines (Ashkannejhad and Horton, 2006; Hayward et. al., 2015; Hayward, Horton, and Nuñez 2015). In the case of my work, I aim to use this ability to enable restoration.
Summary of Proposed Work
In order to assess the potential use of fungi to improve restoration I proposed the following objectives for my work at the APBP:
1) Investigate fungal communities associated with naturally established pitch pine seedlings at varying distances from existing pine stands using molecular techniques to determine fungal identities.
2)Experimentally introduce pine seedlings grown with or without criticalfungal partnersto sites of previous restoration success or failure to determine if pine seedling establishment is improved by reintroduction with their fungal partners.
Work completed
In anticipation of the summer field work and experiments, 220 pitch pine seedlings were planted in sterile soil in the lab at SUNY ESF. 100 of these seedlings were inoculated with live fungal spores collected from the APBP in the fall of 2015. A complementary 100 seedlings were given an equivalent amount of autoclaved, dead spores. The final 20 seedlings were given neither live nor dead inoculum. These seedlings were maintained in a laboratory growth chamber over the course of the summer.
At the start of the 2016 summer I met with the director and several employees of the APBP, my advisor Dr. Tom Horton, and a prospective collaborator of his, Dr. Jeff Corbin of Union College at the Pine Bush Discovery Center to begin organizing the summer’s work. In that meeting it became clear that some of the planned methods for achieving the above objectives would need to be modified because the truth in the field was less clear than the proposed project assumed.
First, there is a dearth of naturally establishing seedlings beyond certain areas of the pine bush (which may be related to fungal dynamics as well). This prevented use of the planned method for completing the first objective. Second, the nature of pitch pine restoration efforts and record keeping lead to uncertainty about suitable sites for experimentalmanipulation as well as timing of experimental planting.
In order to address the first concern rather than harvesting naturally establishing seedlings and examining their roots, soil was collected from three different site types for a bioassay using pitch pine. Soils were collected from black locust stands, recently restored stands, and mature pitch pine stands that had never been invaded. Pitch pine grown in these soils and the roots of these lab grown seedlings will be examined to determine what mycorrhizal fungi are present in each site type.
The second concern was more problematic to address. Pitch pine seedlings are planted in the APBP by volunteers as part of an Earth Day event each spring. Planting is somewhat informal, often done by families and children without specific location instruction or record keeping. As a result areas of different restoration success are not as clearly defined or delineated as previously thought and in many cases it was impossible to determine if an area had been planted with pines or not.
I was provided with maps by the pine bush staff which I then used to survey the pine bush to determine areas of relative success and failure of these plantings and to identify sites for the experimental planting of seedlings with or without their fungal partners. Based on my observations, site selection will instead be based on site history rather than restoration success.
Future work
Despite changes to methods and timing, the work that was started this summer is still ongoing. Soil collected from the pine bush will soon be used in the bioassay to investigate the mycorrhizal communities present. The harvesting and analyses of these seedlings is expected to be completed in the fall of 2017.
Lab grown seedlings will be planted into areas of recent black locust removal or into areas with mature pitch pine that were never invaded. It is expected that seedlings which have been growing with their fungal partners will be more successful than those grown without, and importantly, that this will be observed in areas of recent black locust removal because these areas are expected to be the most inhospitable to natural pine establishment. Planting will be done in the spring of 2017 because of the delay in site selection over the summer and the suggestion by pine bush staff. Harvesting and analyses will be done fall of 2017.
Additionally, through the Preserve and my advisor I have been in contact with Dr. Jeff Corbin of Union College, who has been studying the plant communities and soil nitrogen dynamics of the pine bush. Black locust increase nitrogen in soils where they are present. It is hoped that collaboration with Dr. Corbin will bring more information and increase the strength of any findings from my experiments by incorporating a new dimension relating to soil nutrients.
Acknowledgements
I am very grateful to the Albany Pine Bush Preserve Commission, especially my Sussman sponsor director Neil Gifford, Amanda Dillon, and Steven Campbell for their expertise and resources. I would also like to thank my advisor Dr. Tom Horton for instruction as well as creative ideas and problem solving and Aimee Hudon, for her help with field work. This work would not have been possible without the generous funding of the Edna Bailey Sussman Foundation.
Literature Cited
Ashkannejhad S, Horton TR (2006) Ectomycorrhizal ecology under primary succession on
coastal sand dunes: interactions involving Pinus contorta, suilloid fungi and deer. New Phytologist 169:345-354.
Hayward J, Horton TR, Pauchard A, Nuñez MA (2015) A single ectomycorrhizal fungal species
can enable a Pinus invasion. Ecology 96: 1438-1444
Hayward J, Horton TR, Nuñez M (2015) Ectomycorrhizal communities coinvading with
Pinaceae species in Argentina: Gringos bajo el bosque. New Phytologist208: 497-506