Pile burn scar restoration at Lily Lake: tradeoffs between abundance of non-native and native species
Date
2019
Authors
Sexton, Ian C., author
Brown, Cynthia S., advisor
Fornwalt, Paula J., committee member
Paschke, Mark W., committee member
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Abstract
Accumulation of fuels in forests across the western United States is producing larger and more severe wildfires. To decrease wildfire severity and increase forest resilience, foresters regularly remove excess fuel by burning woody material in piles. This common practice can also cause persistent ecosystem changes that include alteration of soil physical and chemical properties due to extreme soil heating, which can favor invasion by non-native plant species. Abundance and species richness of native plant communities may also remain depressed for many years after burning has removed vegetation and diminished propagules in the soil. This adds to the vulnerability of burned areas, which can transition to dominance by invasive species. Research into the use of revegetation techniques following pile burning to suppress invasion is limited. Studies conducted in various woodland types that investigated revegetation of pile burn scars have met with varying success. To assess the effectiveness of restoring pile burn scars in Rocky Mountain National Park, Colorado, we monitored vegetation in 26 scars at Lily Lake the growing season after burning. Later that summer we selected 14 scars for restoration that included soil scarification, seed addition, and pine duff mulch cover. We monitored the scars for 3 years following restoration and found that cover of seeded species exceeded surrounding unburned areas. This suppressed cover of non-native species as well as native species that were not seeded during restoration relative to controls. Productivity of a native forb planted as seed in scars 3 years after restoration was depressed relative to unrestored scars. We conclude that restoration of pile burn scars can be a useful management tool that will likely need to be part of an integrated pest management program addressing preexisting infestations near scars. Monitoring for periods longer than 3 years will help us understand how long suppression of native and non-native species by restoration species may persist.
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Subject
invasive
fire
restoration