University of Nevada, Reno Stoichiometry and Spatial and Temporal Variability in Abundance and Secondary Production of Baetis tricaudatus Dodds (Baetidae: Ephemeroptera) in the Walker River system, Lyon County, Nevada and Mono County, California A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Biology By Diane Henneberry Dr. Donald W. Sada/Thesis Advisor August, 2009 THE GRADUATE SCHOOL We recommend that the thesis prepared under our supervision by DIANE KYUNG RAN HENNEBERRY entitled Stoichiometry And Spatial And Temporal Variability In Abundance And Secondary Production Of Baetis Tricaudatus Dodds (Baetidae: Ephemeroptera) In The Walker River System, Lyon County, Nevada And Mono County, California be accepted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Donald W. Sada, Ph. D., Advisor Kumud Acharya, Ph. D., Committee Member Jeffrey G. Baguely, Ph. D., Graduate School Representative Marsha H. Read, Ph. D., Associate Dean, Graduate School August, 2009 i Abstract: River and stream biological communities vary in response to characteristics of the environment. In 2007 and 2008, populations of Baetis tricaudatus Dodds (Baetidae: Ephemeroptera) were examined to assess spatial and temporal variability in its length- mass relationships, secondary productivity and stoichiometry in the Walker River, California and Nevada. Baetis tricaudatus was most abundant at higher elevations and in woody debris habitats. Its abundance, body mass, and body length were greatest during spring and summer. Body length and mass relationships varied temporally and spatially. Carbon (C):phosphorus (P) ratios were low during summer and autumn, and high during spring and winter. Low C:P raitos during summer and autumn matched spring and winter body and length growth patterns, suggesting that optimal grazing took place during summer and autumn when food quality was high. Stoichiometry and diet analysis suggested that food quality affects Baetis tricaudatus growth and abundance in the Walker River. This study documents that Baetis tricaudatus growth, body length and mass, and stoichiometry varies spatially and temporally in the Walker River through physical and chemical constraints. ii Acknowledgments: Funding for this project was provided by Public Law 109-103, Section 208(a) through the U.S. Bureau of Reclamation and supported by the Desert Research Institute (DRI) through a Graduate Aid position. I am grateful for the funding of this project and also grateful to DRI for Graduate Aid position. This work is one component of a broad examination of the ecology of lotic and lentic systems in the Walker River Basin. Appreciation is given to a number of people that contributed to the completion of this project including, D. Sada, K. Acharya, J. Baguley, C. Rosamond, C. Davis, J. Memmott, C. Fritsen, S. Chandra, and A. Lodhi. I would like to thank my committee for their encouragement, patience and guidance over these past two years. I have learned a great deal, not only from my thesis work but from my courses and field work as well as working and interacting will all of you. Dr. Acharya thank you for allowing me to study stoichiometry with you and guiding me through the in’s and out’s of the stoichiometry process. I would also like to thank the kind members of the Ecological Engineering Laboratory in Las, Vegas for their hospitality and encouragement. I express my appreciation to the hard workers in the Aquatic Ecology laboratory and Chris Rosamond for his guidance and lessons in taxonomy. Thank you all for such a great opportunity of being a part of such a wonderful in depth important river project. I also thank Dr. Fritsen and the Systems Microbial Ecology laboratory for their expertise in diatom identification and the permission and use of their microscope and imaging software. I express my appreciation to Mr. Jeramie Memmott who provided me iii with a number of spreadsheets filled with important periphyton data. Thank you to Clinton Davis and Andy Rost for their help and encouragement. Finally, I would like to thank all my friends and family who have supported me through my journey as a master’s student and seeing it to completion. I would especially like to thank my husband, Eric Momberg for his constant support, wise words, and countless hours of reviewing my thesis and enduring my rants on river organisms. iv Table of Contents: Page # List of Table v List of Figures vi-vii Project Introduction 1 Site Description 6 Chapter 1. A spatial and temporal view: An examination of selected 9 environmental factors affecting abundance and distribution of Baetis tricaudatus in the Walker River Introduction 9 Materials and Sample Methods 12 Analytical Methods 15 Results 15 Discussion 36 References 39 Chapter 2. Length-mass relationships and secondary production of Baetis 45 tricaudatus in the Walker River Introduction 45 Materials and Sample Methods 48 Analytical Methods 50 Results 51 Discussion 58 References 64 Chapter 3. Ecological stoichiometry of Baetis tricaudatus: relationships 68 between body length and mass, phosphorus content and their food in the Walker River. Introduction 68 Materials and Sample Methods 72 Analytical Methods 73 Results 75 Discussion 81 References 87 iv List of Tables: Page # Table 1. Location and Site Names 8 Table 2. Physical and chemical characteristics of the Walker River 16 Table 3. A List of most dominant Algal Taxa from the Walker River 32 Table 4. Average length-mass of B. tricaudatus in the Walker River 51 Table 5. Length-mass predictive equations for each site 55 Table 6. Secondary production size-frequency method 56 Table 7. Cohort production interval options for B. tricaudatus 56 vi List of Figures: Page # Chapter 1. Figures: Figure 1. Walker River Basin Map with site locations 8 Figure 2. Sampling layout 13 Figure 3. Mean water column velocity (m/s) by site (riffle habitat) 19 Figure 4. Mean water column velocity (m/s) by site (woody debris habitat) 19 Figure 5. Mean water column velocity (m/s) by season within site (riffle 20 habitat) Figure 6. Mean water column velocity (m/s) by season within site (woody 20 debris habitat) Figure 7. Mean water column velocity (m/s) by habitat 21 Figure 8. Mean water column velocity (m/s) by habitat within site 21 Figure 9. Mean substrate (cm) by site in riffle habitats 22 Figure 10. Mean substrate (cm) by season with in site 23 Figure 11. Mean maximum temperature (◦C) by site 24 Figure 12. Mean minimum temperature (◦C) by site 24 Figure 13. Mean maximum and minimum temperature (◦C) by site 25 Figure 14. Mean maximum and minimum temperature (◦C) by season 25 Figure 15. Mean maximum and minimum temperature (◦C) by season within 26 site Figure 16. Mean B. tricaudatus abundance (N/m2) by site 27 Figure 17. Mean B. tricaudatus abundance (N/m2) by season within site 28 Figure 18. Mean B. tricaudatus abundance (N/m2) by site during 2007 and 28 2008 Figure 19. Mean B. tricaudatus abundance (N/m2) by habitat within site 29 Figure 20. Mean B. tricaudatus abundance (N/m2) by habitat 30 Figure 21. Mean B. tricaudatus abundance (N/m2) by habitat within season 30 Figure 22. Mean chl_a abundance (µg/cm2) by site (riffle habitat) 33 vii Figure 23. Mean chl_a abundance (µg/cm2) by site (woody debris habitat) 34 Figure 24. Mean chl_a abundance (µg/cm2) by habitat 34 Figure 25. Mean chl_a abundance (µg/cm2) abundance by habitat within site 35 Figure 26. Mean chl_a abundance (µg/cm2) habitat within season 35 Chapter 2. Figures: Figure 27. Mean B. tricaudatus body mass (g) by season within site 52 Figure 28. Mean B. tricaudatus body mass (g) by site 52 Figure 29. Mean B. tricaudatus length (mm), by season within site 53 Figure 30. Mean B. tricaudatus length (mm), by site 54 Figure 31. Length-mass regression between sites in the Walker River 55 Figure 32-38. B. tricaudatus Length Frequency Histograms 57-58 Chapter 3. Figures: Figure 39. Mean total phosphorus concentrations by site 75 Figure 40. Mean total phosphorus concentrations by season 76 Figure 41. Mean total nitrogen concentrations by site 77 Figure 42. Mean total nitrogen concentrations by season 77 Figure 43. Mean B. tricaudatus % body phosphorus by site 78 Figure 44. Mean B. tricaudatus % body phosphorus by season within site 79 Figure 45. Mean B. tricaudatus % body phosphorus by habitat 79 1 Project Introduction: Spatial and temporal variability of the physicochemical and biological characteristics of rivers and streams are heterogeneous at scales from millimeters to tens of kilometers (Minshall et al. 1983, Minshall 1988, Pringle et al. 1988, Giller et al. 1994). This variability influences individual populations, community structure and ecosystem function (Pacala 1987, Hastings 1990, Kareiva 1990, Turner and Gardner 1991, Palmer 1992, Ives et al. 1993, Tilman 1994, Cooper et al. 1997, Wiens 1989, Levin 1992, Anderson et al. 2005) throughout the river’s continuum. Individual populations and communities of various flora and fauna within river and stream environments respond differently to physical and chemical variation. These variations (e.g., current velocity, substrate, temperature and food resource quality and quantity) influence habitat characteristics that provide oxygen, shelter, food, and necessary life history requirements for an organism. Macroinvertebrates, specifically Baetis tricaudatus Dodds (B. tricaudatus) populations, may be influenced by spatial and temporal variation of physicochemical characteristics through variability in their stoichiometric ratios, length- mass relationship, secondary production and diet throughout a river’s continuum. River and stream morphology is shaped by flood frequency, magnitude, and duration, as well as the volume, velocity, and turbulence of flowing water. Many flowing bodies of water in the United States are regulated or diverted for anthropogenic purposes, such as agriculture. These regulations can disrupt the natural hydrology of the system, affecting biological communities that rely on the transportation of specific substrate and removal of nutrients provided by the rivers current.