Abstract Detail


Donoso, Marco [1], Gorchov, David [2].

Long -term impacts of the interactive effects impacts of the invasive shrub, Lonicera maackii and white-tailed deer, Odocoileus virginianus, on native tree seedlings and shrubs.

In many forests in the eastern U.S. the density of tree seedlings and saplings is inadequate for forest regeneration. This ‘regeneration failure’ has been attributed to high densities of white-tailed deer (Odocoileus virginianus) and invasive plants, as well as climate change. Both deer and Amur honeysuckle [Lonicera maackii (Rupr.) Herder, Caprifoliaceae], an invasive shrub, have well documented effects on woody plants in forest understories, but little is known of their long-term effects and how these effects interact. We investigated effects after 11 years of a factorial deer exclusion X L. maackii removal experiment on woody vegetation in the Miami University Natural Areas near Oxford, Ohio. In 2020 five deer exclosures were constructed and paired with five deer access plots (all 20 x 20 m); in half of each plot all L. maackii was cut and removed. All woody stems > 0.3 m tall were censused in summer 2021, pooled by half-plot, and analyzed with a split-plot model. Deer exclusion resulted in greater tree seedling richness and density, non-native shrub (exclusing L. maackii) richness, native vine density and basal area, and canopy cover at 0.3 m above ground. In contrast, none of these woody plant parameters were significantly affected by L. maackii treatment (removal v. present). The deer X L. maackii interaction was significant for native tree seedling richness and density, and total vine density. For each of these last three parameters, values were greatest where deer were excluded and L. maackii was removed, and similar across the other three treatment combinations. This suggests that deer mitigate the negative effects of L. maackii, or L. maackii mitigates the negative effect of deer, or both. For each of the tree seedling parameters, the effect of deer exclusion was greater in 2021 than it was when measured in 2015, indicating that longer periods of deer exclosure enhance tree regeneration. The synergistic effects of excluding deer and removing L. maackii indicate that management of both stressors is ideal for overcoming regeneration failure in forest understories. However, if resources are insufficient to manage both, reducing deer density will be more effective than invasive shrub management.

1 - Miami University, Biology, 700 East High St., Department of Biology, Oxford, OH, 45056, United States
2 - Miami University, Department Of Biology, Pearson Hall, Oxford, OH, 45056, United States

non-native species
regeneration failure
browse impacts
deciduous forest.

Presentation Type: Oral Paper
Number: EC09003
Abstract ID:235
Candidate for Awards:None

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