Dynamics of Daphnia lumholtzi in Pueblo Reservoir A Master’s Thesis Presented to the Faculty of the College of Science and Mathematics Colorado State University-Pueblo Pueblo, Colorado In Partial Fulfillment of the Requirements for the Degree of Master of Science in BIOLOGY By Candace Walker Colorado State University – Pueblo Spring 2014 CERTIFICATE OFACCEPTANCE This Thesis is Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in Biology By Candace Walker Has Been Accepted By the Graduate Faculty of the College of Science and Mathematics Colorado State University-Pueblo APPROVAL OF THESIS COMMITTEE ________________________________________________________________________ Graduate Advisor (Dr. Scott Herrmann) Date ________________________________________________________________________ Committee Member (Dr. Brian Vanden Heuvel) Date ________________________________________________________________________ Committee Member (Dr. DelWayne Nimmo) Date ________________________________________________________________________ Graduate Director (Dr. Jeff Smith) Date ii ACKNOWLEDGEMENTS I would like to thank the following for their contributions in funding and support: James Melby, John Beaver, Board of Pueblo County Commissioners, Board of Water Works of Pueblo, Lower Arkansas Valley Water Conservancy District, U.S. Bureau of Reclamation, Regional Access Graduate Education, Arkansas River Basin Water Forum, Dr. Richard Kreminski, Dr. Scott Herrmann, Dr. DelWayne Nimmo, and Jim Carsella. Without each of these people and organizations, it would not have been possible to carry out the research and statistical analyses that were the essence of the thesis. Arriving at this point in my education took the help of all of my professors to whom I would like to offer my gratitude: Dr. Scott Herrmann, Dr. Igor Melnykov, Dr. Moussa Diawara, Dr. Brian Vanden Heuvel, Dr. Jeff Smith, Dr. Perry Cabot, Dr. Frank Zizza, Dr. Dan Caprioglio, and Dr. Lee Anne Martinez. Taking courses under these instructors opened my eyes to a number of new interests and passions and for that I am immensely grateful. There are several additional people that went out of their way to be helpful on a regular basis: Dr. Helen Caprioglio, Theresa Jimenez, Stacy Righini, Derek Moore, and Kenneth McKenzie. These are some of the most prompt and efficient individuals at aiding students. They are blessed with the unique ability of making a person feel like they are of the utmost importance and do so without hesitation, even with busy schedules of their own. To say that I appreciate them would barely scratch the surface. I have to give special recognition to Roy Jo Sartin and Erin DeCuir of the Graduate Student Support Center (GSSC). A large amount of my time was spent in the support center where I benefited from a quiet place to write and run statistical analyses. During this time, these two women took every opportunity to help with manuscript editing and presentation delivery and iii offered much encouragement on a daily basis. Stressful times were instantly alleviated by their laughter and uplifting presence. They have become dear friends to me and I will always cherish my time spent with them. There is no way to begin to thank my thesis committee. In my book, Dr.’s Herrmann, Nimmo, and Vanden Heuvel are nothing short of legendary in their careers. To have my name anywhere associated with this group of distinguished gentlemen is a privilege beyond words. Getting to work with Dr. Herrmann and Dr. Nimmo was a joy and I know I am one of the precious few that can use the word “joy” in the context of a master’s thesis. Their expertise and knowledge was tremendous, and I will always be overwhelmed with appreciation for their willingness to pass it down to my level. Thank you. I cannot complete this section without thanking my family. My husband is the eternal optimist, always offering unwavering encouragement, always instilling his faith in me. Thank you for inspiring me to be resilient and positive. To my sweet-hearted children, my most favorite people in the world, thank you for giving me a reason to want to better myself and thank you for tolerating the time spent doing so. Thank you to my mom, dad, and brother for all of the times you offered listening ears and words of reassurance. There is no way I could have done this without you. iv ABSTRACT Ours is the first report of the occurrence of Daphnia lumholtzi, an invasive zooplankter, in Pueblo Reservoir, Colorado. Six sites were surveyed from 2008-2010 and four were revisited in 2013. Our study involved the investigation of dynamics pertaining to D. lumholtzi’s presence, including density changes from 2008 to 2013, community composition, and variation in abiotic parameters. Sites with abundant D. lumholtzi showed significant differences in species assemblage and physical properties and an increase in population density for the zooplankter was observed. The observations of this study can be used to generate a plethora of experimental hypotheses for future work as well as provide valuable baseline data for managing the lake to better serve the needs of wildlife and utilities. v Table of Contents Page Numbers BACKGROUND and SIGNIFICANCE 1-18 Pueblo Reservoir 1 Invasive Species 4 Daphnia lumholtzi: Native Range 7 Daphnia lumholtzi: North America Invasion, Dispersal and Success 10 Previous Colorado Plankton Studies 17 HYPOTHESES 19-20 SPECIFIC AIMS 20 MATERIALS and METHODS 21-29 Study Site 21 Zooplankton Collection 21 Phytoplankton Collection 25 Water Quality Parameters 25 Statistical Analyses 28 RESULTS 30-54 DISCUSSION 55-62 CONCLUSION 63-64 REFERENCES 65-79 APPENDICES 80-110 A: Additional Methods Information 80 B: Additional Statistical Analyses 98 C: Data Concerning Daphnia lumholtzi 105 vi LIST of TABLES Page Numbers Table 1. Zooplankton sample dates and sites in Pueblo Reservoir 24 Table 2. Phytoplankton sample dates and sites in Pueblo Reservoir 26 Table 3. The 95% confidence interval for the slope of regression lines fit to log transformed density of D. lumholtzi in 2008, 2009, 2010, and 2013 32 Table 4. Chi square goodness-of-fit homogeneity tests for comparing density of D. lumholtzi among the four sample sites. 34 Table 5. PERMANOVA table of results for environmental variables by date and site factors 35 Table 6. Canonical analysis of principal coordinates for environmental parameters grouped by site for samples taken in 2013 35 Table 7. Canonical analysis of principal coordinates for environmental parameters grouped by date for samples taken in 2013 36 Table 8. PERMANOVA table of results for phytoplankton variables by date and site factors 38 Table 9. Canonical analysis of principal coordinates for phytoplankton grouped by site for samples taken in 2013 38 Table 10. Canonical analysis of principal coordinates for phytoplankton grouped by date for samples taken in 2013 41 Table 11. PERMANOVA table of results for zooplankton variables by date and site factors 45 Table 12. Canonical analysis of principal coordinates for zooplankton grouped by site for samples taken in 2013 46 Table 13. Canonical analysis of principal coordinates for zooplankton grouped by date for samples taken in 2013 48 Table 14. Zooplankton occurrence in Pueblo Reservoir 2013 52 Table 15. Chi square goodness-of-fit tests comparing proportions of cladocerans, copepods, and rotifers in the month of September 53 vii LIST of FIGURES Page Numbers Figure 1. Historic end of month content of Pueblo Reservoir 22 Figure 2. Site map of Pueblo Reservoir 23 Figure 3. Average density of Daphnia lumholtzi and native daphnids 30 Figure 4. Average biomass of Daphnia lumholtzi and native daphnids 31 Figure 5. Log transformed density of D. lumholtzi from 2008-2010 and 2013 32 Figure 6. Abundance of D. lumholtzi: distribution among sites in each of the sampling years 33 Figure 7. Canonical analysis of principal coordinates according to site of environmental data 36 Figure 8. Canonical analysis of principal coordinates according to date of environmental data 37 Figure 9. Canonical analysis of principal coordinates according to site of phytoplankton data with Bacillariophyta vector overlay 39 Figure 10. Canonical analysis of principal coordinates according to site of phytoplankton data with Chlorophyta vector overlay 39 Figure 11. Canonical analysis of principal coordinates according to site of phytoplankton data with other classification vector overlay 40 Figure 12. Canonical analysis of principal coordinates according to date of phytoplankton data with Bacillariophyta vector overlay 42 Figure 13. Canonical analysis of principal coordinates according to date of phytoplankton data with Chlorophyta vector overlay 43 Figure 14. Canonical analysis of principal coordinates according to date of phytoplankton data with other classification vector overlay 44 Figure 15. Canonical analysis of principal coordinates according to site of zooplankton data with cladoceran vector overlay 46 Figure 16. Canonical analysis of principal coordinates according to site of zooplankton data with copepod vector overlay 47 viii Figure 17. Canonical analysis of principal coordinates according to site of zooplankton data with rotifer vector overlay 47 Figure 18. Canonical analysis of principal coordinates according to date of zooplankton data with cladoceran vector overlay 49 Figure 19. Canonical analysis of principal coordinates according to date of zooplankton data with copepod vector overlay 50 Figure 20. Canonical analysis of principal coordinates according to date