Background/Question/Methods Amur honeysuckle (Lonicera maackii), a non-native, invasive shrub, has spread into woodlands in much of the eastern US, altering understory dynamics and forest structure. Midwestern states, including Iowa, have been working to remove honeysuckle from forests using multiple methods, including aerial treatment with glyphosate, a technique that can be used to treat large areas at low cost with high effectiveness. This study aims to quantify changes in community composition and species densities in the forest breeding bird community 4-5 years after the rapid removal of honeysuckle from the shrub layer. We conducted point counts and manually sampled vegetation on three sprayed and five unsprayed control stands (totaling 534 acres) in upland oak dominated forest at three sites in southern Iowa. In addition, we measured the 3D forest structure with a terrestrial laser scanner (TLS). This technique may provide a more accurate measure of the structure birds respond to when compared with manual measurements. Results/Conclusions Control stands contained significantly more live honeysuckle, with an average 10,607 live honeysuckle stems/acre while the sprayed stands had 3,030 stems/acre (p<0.01). In an analysis including only forest and edge species, the control plots averaged 10.7 birds/acre and the sprayed plots averaged 8.8 birds/acre. We expect species-specific analyses to show that this trend is driven primarily by lower densities of common shrub nesting birds and only slightly higher densities of aerial insectivores and ground nesting birds in sprayed stands when compared to the control. Results will provide land managers with more detailed information to help them make decisions about where to remove honeysuckle and inform follow up management actions for species that may be negatively impacted.
