Wright State University CORE Scholar Browse all Theses and Dissertations Theses and Dissertations 2014 Direct and Indirect Effects of White-Tailed Deer (Odocoileus virginianus) Herbivory on Beetle and Spider Assemblages in Northern Wisconsin Elizabeth J. Sancomb Wright State University Follow this and additional works at: https://corescholar.libraries.wright.edu/etd_all Part of the Biology Commons Repository Citation Sancomb, Elizabeth J., "Direct and Indirect Effects of White-Tailed Deer (Odocoileus virginianus) Herbivory on Beetle and Spider Assemblages in Northern Wisconsin" (2014). Browse all Theses and Dissertations. 1375. https://corescholar.libraries.wright.edu/etd_all/1375 This Thesis is brought to you for free and open access by the Theses and Dissertations at CORE Scholar. It has been accepted for inclusion in Browse all Theses and Dissertations by an authorized administrator of CORE Scholar. For more information, please contact [email protected]. DIRECT AND INDIRECT EFFECTS OF WHITE-TAILED DEER (Odocoileus virginianus) HERBIVORY ON BEETLE AND SPIDER ASSEMBLAGES IN NORTHERN WISCONSIN A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science By Elizabeth Jo Sancomb B.S., University of Maryland, 2011 2014 Wright State University WRIGHT STATE UNIVERSITY GRADUATE SCHOOL July 21, 2014 I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPERVISION BY ElizABeth Jo SAncomb ENTITLED Direct And indirect effects of white-tailed deer (Odocoileus virginianus) herBivory on Beetle And spider AssemblAges in Northern Wisconsin BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master of Science ___________________________________________ Thomas Rooney, Ph.D. Thesis Director ___________________________________________ David Goldstein, Ph.D., Chair DepArtment of BiologicAl Sciences College of Science And MAthematics Committee on FinAl ExAminAtion ____________________________________________ Don Cipollini, Ph.D. ____________________________________________ Thomas Rooney, Ph.D. ____________________________________________ John O. Stireman III, Ph.D. ____________________________________________ Robert E. W. Fyffe, Ph.D. Vice President for Research And Dean of the Graduate School ABSTRACT Sancomb, Elizabeth Jo. M.S. Department of Biological Sciences, Wright State University, 2014. Direct and indirect effects of white-tailed deer (Odocoileus virginianus) herbivory on beetle and spider assemblages in Northern Wisconsin White-tailed deer directly impact vegetation structure and species composition through selective foraging, and indirectly impact other species by altering habitat, food-web interactions, and microclimate. I examined the direct effects of deer exclusion on vegetation communities, and indirect effects on beetle, spider, and web-building spider (WBS) assemblages. Forb and woody plant percent cover were higher in exclosures, while graminoid cover was higher in controls. There were no differences in beetle and spider assemblages between browsed and protected areas. The absence of differences could be attributed to legacy effects, or alternatively high vagility of individuals. WBS assemblages were more abundant and diverse in protected areas, reflecting differences in web site availability and litter depth. This suggests indirect effects of deer alter arthropod assemblages. Through selective feeding, deer act as ecosystem engineers. They are indirectly changing the WBS assemblages in this area, and may be changing beetle and spider assemblage composition. iii TABLE OF CONTENTS Page I. INTRODUCTION AND OBJECTIVES................................................................1 Indirect effects and ecosystem engineers...................................................1 Direct effects of White-tailed deer on forest vegetation..............................2 Indirect effects of deer on co-occurring animal assemblages.....................3 Direct and indirect effects of deer on arthropod assemblages....................4 Objectives...................................................................................................6 II. METHODS.........................................................................................................8 Study Area and Sites..................................................................................8 General Sampling.......................................................................................9 Vegetation Sampling.................................................................................10 Sweep Net Sampling.................................................................................11 Pitfall Sampling.........................................................................................12 Web-Building Spider Sampling.................................................................13 Data Analysis............................................................................................14 III. RESULTS.......................................................................................................20 Vegetation.................................................................................................20 Beetles......................................................................................................23 Spiders......................................................................................................28 Web-Building Spiders................................................................................33 Power analysis..........................................................................................38 iv IV. Discussion AND CONCLUSIONS..................................................................40 Vegetation.................................................................................................40 Beetles and Spiders..................................................................................41 Web-Building Spiders................................................................................43 Conclusions...............................................................................................45 V. REFERENCES................................................................................................48 VI. APPENDIX.....................................................................................................53 v LIST OF FIGURES Figure Page 1. Total percent vegetation cover.........................................................................20 2. Forage type percent cover...............................................................................21 3. Average vegetation height...............................................................................22 4. Total beetle rarefaction....................................................................................23 5. Beetle assemblage composition......................................................................24 6. Herbivorous beetle rarefaction.........................................................................25 7. Carabid beetle diversity...................................................................................25 8. Carabid beetle rarefaction................................................................................26 9. Total spider abundance...................................................................................28 10. Total spider rarefaction..................................................................................28 11. Spider assemblage composition....................................................................29 12. Web spider rarefaction...................................................................................30 13. Non-web spider rarefaction............................................................................30 14. Beetle and spider assemblage composition..................................................31 15. Web-building spider abundance....................................................................33 16. Web site availability at 0.5m..........................................................................33 17. Web-building spider rarefaction (family)........................................................34 18. Web-building spider rarefaction (species).....................................................34 19. Web-building spider family composition........................................................35 vi LIST OF FIGURES (Continued) 20. Relative abundance of web type....................................................................35 21. ANCOVA of web-building spider abundance compared across web site availability at 0.5m...............................36 22. ANCOVA of web-building spider richness compared across litter depth...............................................36 23. ANCOVA of web-building spider abundance compared across total prey availability..........................................37 Diagram Page 1. Exclosure/control plot schematic.......................................................................8 2. Web-building spider sampling schematic.........................................................13 vii LIST OF TABLES Table Page 1. Summary of vegetation results........................................................................22 2. Summary of beetle results...............................................................................27 3. Summary of spider results...............................................................................32 4. Summary