Hardwood forest ecosystems were primarily oak and hickory tree species, preserved through natural fires. Due to fire suppression in the last century, invasion of insect pests, and changing climate, these forests are slowly changing to domination by maples and beech. One strategy of oak and hickory regeneration is utilizing prescribed burns to create an open understory for fire-tolerant oak and hickory seedlings to establish and grow. Invertebrates have shown to be beneficial bio-indicators for forest regeneration and biodiversity in other ecosystems. We studied how prescribed burns affect invertebrate biodiversity, and whether time since burn shows recovery of the invertebrate community. The Hardwood Ecosystem Experiment (HEE) in southern Indiana is long-term study of forest-management practices including different methods of timber harvest and prescribed burns At the HEE, we established 6 forest stands that were recently burned, each paired with an adjacent, undisturbed stand with similar pre-burn characteristics. At each stand, we ran a 50-m transect with 6 locations for pitfall traps and 3 litter samples at regular intervals along each transect. Invertebrates were extracted from leaf litter using the Winkler extraction method. Pitfalls were later sorted, and beetles were identified to family. We recorded canopy tree species cover, DBH for surrounding trees, and categorized woody debris along the transect. We found unmanaged forest patches have greater beetle and invertebrate biomass and biodiversity, but there is not a significant difference. Consequently, there is rapid recovery of invertebrate communities post burn. Local stand characteristics were the strongest influences on invertebrate biomass and community composition regardless of burn treatment. The community resilience to burn may indicate hardwood forests are adapted to historical fire management. It appears prescribed burns do not affect invertebrate communities in the short term and can be used in managing hardwood ecosystems without reducing invertebrate biomass or diversity. However, if understory composition is changed by burns, the composition of the tree canopy may be altered in the future. Studies several decades post burn would be telling of long-term effects of burns on invertebrate communities. As I continue through my career in biology, I will take away my experiences with field work, lab work, collaborative planning, and execution of my own inquiries through my future endeavors.
Author: Clara Moiseyeva
Faculty Advisor: Thomas Crist, Biology
Graduate Student Advisor: Gwendolyn Lloyd, Biology
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