Mitchell J Kukla



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A major threat to forest ecosystems are invasive species such as Lonicera maackii (Amur honeysuckle), a shrub that has been shown to greatly increase understory shading in forests. Our aim was to understand how herbaceous layer species richness and abundance are impacted by invasion of L. maackii along forested headwater streams in southwestern Ohio. The herbaceous layer was sampled in 60 1-m2 plots along 5 headwater streams representing a gradient of honeysuckle invasion intensity: reference, moderate, and heavy. Within 12 plots at each site, percent cover was estimated for each species in April, June, and August. For all three sampling dates, herbaceous cover did not differ significantly among sites. Significant differences in species richness were found in April and June (ANOVA; P < 0.001). The Englewood Reference site had significantly higher richness than the Aullwood Reference site in April and June (P < 0.005), which we believe was due to differences in environmental and soil properties between the sites. The Englewood Reference site also had significantly higher richness than the Englewood Moderate site in April (P = 0.024) and the heavily invaded Buckeye Trail site in June (P = 0.00083). Further, Floristic Quality Assessment Index values were examined in each site. In each month, zero non-native plants were found in the Englewood Reference and Englewood Moderate sites. In April and June, there were more non-native species present in the Buckeye Trail site than the Charleston Falls and Aullwood sites. In summary, these results suggest that Amur honeysuckle had a negative influence on herb layer diversity, but not cover. In addition, the increased presence of other non-native species in the heavily invaded site suggests that L. maackii may be altering the composition of the herbaceous layer. Further analyses will examine how herb community composition differs among sites using non-metric multidimensional scaling.

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Project Designation

Independent Research - Undergraduate

Primary Advisor

Ryan W. McEwan

Primary Advisor's Department



Stander Symposium project

Herbaceous layer species richness along forested headwater streams is negatively impacted by Amur honeysuckle (Lonicera maackii) invasion