Forest Bird Community Response to Honeysuckle Control from Aerial Spraying Lucas Goldschmidt1, Summer Wolfe2, Justin Shew3, Brian Stoff3, and Eric Wright3 1University of Illinois Urbana-Champaign Contact:
[email protected] 2Southwestern Illinois College, 3National Great Rivers Research and Education Center
Introduction
Results
Biodiversity
Cumulative Species Richness 15
Mean Richness (95% CI)
2.3 2.2 2.1 2 1.9 1.8
Figure 2.
Objectives
Aerial Spray
Aerial Spray & Burn Treatment
Control
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Discussion & Conclusion
12 11 10
Figure 3. Aerial Spray
Aerial Spray & Burn
Control
Treatment
Figures 2 & 3. Plot of mean (95% CI) biodiversity and cumulative species richness across treatments.
P = 0.24, Kruskal-Wallis test.
P = 0.29, Kruskal-Wallis test
Figures 4 & 5. Boxplots of biodiversity and cumulative species richness across treatments. Figure 4.
Figure 5.
Northern Cardinal Abundace Mean Individuals per point (95% CI)
Figure 1
Wood Thrush Abundance
1.5 1.2 0.9 Photo 1 by Jenny Runner Photo 2 by Corey Hayes
0.6 0.3 0
Figure 6.
Aerial Spray
Aerial Spray & Burn Treatment
Control
1028 individual birds and 47 different species were detected from the surveys. While aerial sprayed sites tended to have higher species richness and biodiversity, Kruskal-Wallis tests showed neither of the differences to be significant (Figures 2-5). Northern Cardinal and the Wood Thrush abundances per point were slightly higher at control points (Figures 6 and 7); however, Kruskal-Wallis tests determined neither of the results to be statistically significant (P = 0.54, for Northern Cardinal and P=0.86, for Wood Thrush).
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Mean Individuals per point (95% CI)
The main objective was to determine the effects of aerial herbicide application on the avian species richness and biodiversity. We were also interested in determining if the treatments had negative effects on understory birds such as the Northern Cardinal and Wood Thrush. Results from this project have the potential to be used to inform land management decisions.
Results (Continued)
46 point-counts stations were surveyed across 22 sites in central west Illinois (Figure 1). 12 control sites had no treatment (23 point-counts), 7 sites were aerial sprayed and burned (16 point-counts), and 3 sites were aerial sprayed (7 point-counts). All count stations were spaced at least 200m apart. All birds were counted within a 100m radius of the point and each survey lasted 5 minutes. Each point was surveyed twice during June 2017. Trained observers were used to complete 92 point-counts. Due to non-normal distributions of investigated responses, nonparametric Kruskal-Wallis tests were used to test for differences across the 3 treatments.
Mean Shannon Index (H')
Bush honeysuckle (Lonicera spp.) is an invasive shrub that can take over native forests and out-compete native vegetation. In Iowa, Missouri, and Illinois, invasive bush honeysuckle has been treated through aerial application of glyphosate rated for aquatic use (RodeoTM). While these treatments can be effective at controlling honeysuckle, little is known about their overall effect on forest wildlife populations. In this study we investigated the effects of the aerial application on bush honeysuckle, as well as aerial application on bush honeysuckle followed with prescribed fire treatment, on the forest bird communities of central west Illinois.
Methods
1.2 1
Throughout the study, it seemed the effects caused by aerial sprayings on avian communities were negligible between the measures of biodiversity and species richness. In the end, the responses investigated were not determined to be significantly different. One concern regarding these management treatments is the possible destruction of understory bird habitat for a few species. Our research suggests the effects of spraying treatments on select understory species abundance was not significant. It will be important to return aerial sprayed pointcounts in the future. We predict that once native understory returns, we may see increases in understory bird populations. Increasing sample size, conducting long-term bird monitoring, and measuring forest microhabitat are needed to fully understand the effects of these treatments on avian communities.
0.8
Acknowledgements
0.6 0.4 0.2 0
Aerial Spray Figure 7.
Aerial Spray & Burn
Control
Treatment
Figures 6 & 7. Mean (with 95% CI) number of Northern Cardinal and Wood Thrush per point-count survey. Both species are understory birds that could be negatively affected by habitat loss from aerial sprays.
I would like to thank the Illinois Department of Natural Resources and NGRREC with their help setting up this project. I would also like to thank Bob Caveny and Phil Cox for their help with gaining access to sites to do point counts and James Henebry for his help with data collection. Finally, I would like to thank the private landowners for allowing us to conduct surveys on their land.
