The role of the soil seed bank in Southern Appalachian wildfire response

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
Kelder C. Monar (Creator)
Institution
Western Carolina University (WCU )
Web Site: http://library.wcu.edu/
Advisor
Beverly Collins

Abstract: Wildfire disturbance is likely to increase in Southern Appalachian forests due to climate change and anthropogenic land-use changes. The soil seedbank can be a source of plant community response after this disturbance. Fire can affect seeds and seed germination both positively and negatively, yet little is known about seedbank response to fire in this region. A seedbank study was conducted in the greenhouse from May 23, 2017 to January 9, 2018 using litter and mineral soil samples from burned (B) and unburned (U) plots in three mid-elevation sites to determine seedbank contribution to first-season plant community response following wildfires that swept through the region in fall, 2016. In addition, extant vegetation, woody and herbaceous seedlings, and environmental variables including canopy openness, litter cover, soil moisture, bare ground cover, temperature and tree and shrub mortality were surveyed in the field over the 2017 growing season. Seedbank-generated plant abundance and species richness were compared between B and U plots, and with field seedling and field tree communities. Seedbank abundance and richness were lower in B samples from the litter layer, but not the soil layer, suggesting that fire killed seeds near the surface but that seeds underground were insulated. Density and richness of field seedlings were higher in B plots than U plots, suggesting that post-fire environmental differences, not changes to the seedbank itself, control forest response to wildfire from the seedbank. High light, low litter, and fluctuating temperature in B plots favored germination. Species that responded most strongly in the field were generalist disturbance-adapted species such as black locust (Robinia pseudoacacia), not species specifically adapted to fire. Some species, such as black locust and birches (Betula spp.), were more common in the seedbank than in extant vegetation. Recruitment from the seedbank after periodic disturbance may allow these species to persist at these sites. Overall, the seedbank can contribute to first-year post-fire vegetation response, and has the potential to shift species composition in Southern Appalachian forests.

Additional Information

Publication
Thesis
Language: English
Date: 2018
Keywords
Disturbance, Fire, Forest, Seedbank, Seeds, Southern Appalachians

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