AUFw'UCHS AND BENTHIC Hl\CROINVERTEBRATE COMMUNITY STRUCTURE ASSOCIATED h'ITH THREE SPECIES OF ROOTED AQUATIC K~CROPHYTES IN LAKE ONALASK~, 1976-1977 A Thesis Submitted to the Faculty of University of Wisconsin - La Crosse La Crosse, Wisconsin 54601 by Bruce Arnold Biltgen In Partial Fulfillment of the Requirements for the Degree of Master of Science in Biology May 1981 UNIVERSITY OF WISCONSIN - LA CROSSE La Crosse, Wisconsin 54601 COLLEGE OF ARTS, LETTERS, AND SCIENCES Candidate: Bruce Arnold Biltaen ----~--------------------- We recommend acceptance of this thesis to the College of Arts, Letters, and Sciences in partial fulfillment of this candidate's requirements for the degree Master of Science in Biology. The candidate has completed his oral defense of the thesis. , J ~~-~~,.~ /~l---</ -?I ) g /i~.l~·~ --.,~~-=--'--r''-'''"",;~_,_-~/;/' / 1 ~ ~ /2./'~ ;9 rJ 7 /2JJ//~~a ~esis Committee Chairman ~ate /f'p;,-/ ._:)"")v, / / 9~/ Date .ora; ----~~~zvn~n~-~.1~~?.~vz4~2~~~-------- / I.:_. Thesis Corrm1ittee Member Date Department of Botany Iowa State University, Ames '1fo-~::,~ ----dihesis Cominittee lfember ca~ .3~ Date This thesis is approved for the College of Arts, Letters, and Sciences. ii ABSTRACT A survey of the Aunwuc.lt6 and benthic macroinvertebrate corrununities associated with vegetated and non-vegetated areas was conducted in Lake Onalaska, Navigation Pool No. 7 of the Upper Hississippi River, between 1976 and 1977. The structure and dynamics of the invertebrate community were investigated. Four sampling sites were studied; a monotypic stand of SpMgmU.u.m e.Wlyc.a!Lpwn, a monotypic stand of SagLt:ta.!Ua fa;t.[6o.ua, a stand of Nymplw..e.a tube)w,sa, and a non-vegetated control site to determine the influence of macrophytes on invertebrate populations. Samples \vere collected at weekly intervals from June until autumnal senescence of vegetation; after that time, samples were collected at two week intervals. On each sampling date, one ponar dredge sample was collected and one macrophyte in the water column \vas removed. The macroinvertebrates were subse­ quently harvested. Five such samples along a transect were pooled to represent one composite sample for each macrophyte stand on each sampling date. Physical and chemical variables were measured at every other s~~ple station on the transect. Taxa, numbers, and biomasses were determined for the Au6wuc.l1.-6 and benthic macroinvertebrates. Time series analyses \.rere conducted for the dominant invertebrate groups. Simple linear correlations among physical-chemical variables and biological variables were also calculated. The macroinvertebrate col".:nunity l·ms dominated (90%-93/~) by eight taxonomic groups including Oligochaeta, Hirudinea, Isopcda, Amphipoda, Gastropoda, Diptera, and Lepidoptera. Increases in benthic inverte­ brates in vegetated sites '"ere observed, corresponding to autumnal macrophytes senescence and in non-vegetated sites, corresponding to winte-r ice cover. Areal benthic production \-las greatest in non-vegetated sites and exceeded Au&wudlh areal production. Water temperature, pH, dissolved oxygen, and alkalinity did not effect the distribution of macroinvertebrates. Fev7 significant correlations 1;-1ere observed bet•.veen numbers of macroinvertebrates/m2 and mc::crophyte surf<1ce area or benveen the Au.t)wu.clt& and benthic cmlliuunities. ACKNOHLEDGEMENTS The author would like to acknowledge committee members who have been instrumental in the completion of this thesis. I am forever indebted to Dr. Thomas Claflin for serving as my major advisor and initiating this research. His devotion to and knowledge of the Upper Mississippi Ri'Jer are inestimable. I thank Dr. Ronald Rada for his dedication and professional criticism in revie\oJing this manuscript and for his sincerity and thoughtfullness. Thanks are also extended to Dr. James Peck for his critical comments on all phases of my work, Dr. Thomas Weeks, whose ceaseless energy will always be a spiritual inspiration, and Dr. John Scheidt for serving on my committee. My appreciation and gratitude are expressed to Hs. Beverly Erickson, who typed the manuscript, and Ms. Gloria Wiener for typing many of the tables. Their patience and persistence have greatly expedited the completion of this thesis. Finally, I thank my parents for giving me encouragement and understanding in my career and education these many years. TABLE OF CONTENTS PAGE LIST OF TABLES . vii LIST OF FIGURES ix LIST OF APPENDICES xi INTRODUCTION . 1 LITERATUP~ REVIEW 2 DESCRIPTION OF THE STUDY AREA 14 The Upper Mississippi River 14 Navigation Pool No. 7 14 Lake Onalaska 15 Hydrography 18 Water Chemistry . 19 Sedimentation . 20 Aquatic Macrophytes . 22 Specific Site Descriptions . 23 23 25 ~ite III - Nymphae.a tube.Jto-t.a 27 Site IV - Control 27 METHODS AND MATERIALS 29 Field Methods 30 Aquatic Macrophytes 30 v Benthic Invertebrates . • 30 Physical-~hemical Variables 30 Laboratory Hethods . 31 Aquatic Hacrophytes 31 Benthic Invertebrates 32 .£.!!. and Alkalinity 32 Sediments 33 RESULTS 34 Site I - SpaJLganiwn e.Myc.aJLpwn 3Lf Site II - Sagitt~a latino!ia . 39 Site III - Nymphaea ;tube.Jto.oa 43 Site IV - Control 47 Oligo chaeta 52 Hirudinea 53 Isopoda . 53 Amphipoda 53 Lepidoptera 55 Diptera 55 Gastropoda 55 Pclecypoda 58 DISCUSSION 60 Oligochaeta 61 Hirudinea 65 Isopoda 69 llmphi_poda 70 Lepidoptera 75 vi Diptera 77 Gastropoda . 84 Pelecypoda • 87 SUM}UillY AND CONCLUSIONS 100 LITERATURE CITED 102 APPENDIX 113 Values of physical, chemical, and biological I. 2 variables and number of invertebrate organisms/m of taxonomic groups in the SpaJtgan{wn eUJtljCiVrpum stand, 1976-1977 ..•.•••.••..•. 113 II. Values of physical, chemical, and biological 2 variables and number of invertebrate organisms/m of taxonomic groups in the Sag~a f~inotia stand, 19 7 6-19 7 7 . • . • • . • • • • . • • • 117 III. Values of physical, chemical, and biological · 2 variables and number of invertebrate organisms/m of taxonomic groups in the Nymphaea t.u.befLoha stand, 1976-1977 ..•••.•...••.• 121 IV. Values of physical, chemical, and biological 2 variables and nlli~ber of invertebrate organisms/m of taxonomic groups in the control site, 1976-1977 125 V. Taxonomic list of Au.nwu.c.h.o and benthic macroinvertebrates collected from all sites, Lake Onalaska, Navigation Pool No. 7, Upper Mississippi River, 1976-1977 • • . • . • • 128 vii LIST OF TABLES TABLE PAGE 1. Mean concentrations and ranges of selected physical and chemical variables of sample sites, Lake Onalaska, Navigation Pool No. 7, Upper Hississippi River, 1976-1977 . • . • . • •.••..•••••. 26 2. Mean standing crop (individuals/m2) and biomass (g/m2) of macroinvertebrates for Au£wttc.ho and benthos, Site I, SpaJLgavu.wn euJtyc.Mpwn, Lake Onalaska, Navigation Pool No. 7, Upper Mississippi River ...•..•..•...••••. 37 3. Relative abundance, frequency of occurrence, rank, and total numbers of each taxonomic group sampled in the SpCVLgavu.wn euJtyc.Mpum stand (Site I), Lake Onalaska, Navigation Pool No. 7, Upper Hississippi River, 1976-1977 . • • • • . • . • • . • • • • . • . 38 4. Mean standing crop (individuals/m2) and biomass (g/m2) of macroinvertebrates for Aut)wudu and benthos, Site II, Sag--lt.tcvUa faX{_£oua, Lake Onalaska, Navigation Pool No. 7, Upper Hississippi River ...•...•. • . • . • 41 5. Relative abundance, frequency of occurrence, rank, and total numbers of each taxonomic group sampled .in the Sagaxa!L)_a tali£olia stand (Site II), Lake Onalaska, Navigation Pool No. 7, Upper Mississippi River, 1976-1977 . • . • . • • • . • . • • • • 42 2 6. Mean standing crop (individuals/m ) and biomass (g/m2) of macroinvertebrates for Aut)vJLtc.h-6 a~d benthos, Site III, Nymrhaea tube)WlJa, Lake Onalaska, Navigation -Pool No. 7, Upper Mississippi River. • . • • . • • • • • . • • • 44 7. Relative abundance, frequency of occurrence, rank, and total numbers of each taxonomic group sampled in the Ntjmphac_a tubetwoa stand (Site III), Lake Onalaska, Navigation Pool No. 7, Upper Nississippi River, 1976-1977 . • • • . • . • . • • . • • 46 8. Mean standing crop (individuals/m2) and biomass of macroinvertebrates, Site IV, Lake Onalaska, Navigation Pool No. 7, Upper Mississippi River. • • • • • 48 viii 9. Relative abundance, frequency of occurrence, rank, and total numbers of each taxonomic group sampled in the control site (Site IV), Lake Onalaska, Navigation Pool No. 7, Upper Hississippi River, 1976-1977 ••••• 50 10. Number of taxa represented by AufiWuQh0 and benthic macroinvertebrates for 5 ranked taxonomic groups at each site, Lake Onalaska, Navigation Pool No. 7, Upper Hississippi River, 1976-1977. •••• 51 11. Taxonomic composition of Hirudinea at each site, Lake Onalaska, Navigation Pool No. 7, Upper Mississippi River, 1976-1977. • •••• 54 12. Taxonomic composition of Diptera at each site, Lake Onalaska, Navigation Pool No. 7, Upper Mississippi River, 1976-1977 ..•••..• 56 13. Taxonomic composition of Gastropoda at each site Lake Onalaska, Navigation Pool No. 7, Upper Mississippi River, 1976-1977 •..••..• 57 14. Taxonomic composition of Pelecypoda at each site, Lake Onalaska, Navigation Pool No. 7, Upper Mississippi River, 1976-1977 ...•.•.• 59 ix LIST OF FIGURES FIGURE PAGE 1. Navigation Pool No. 7 of the Upper Mississippi River. Lake Onalaska lies adjacent to and east of the navigation channel . • . • • • . • . • • • • • • 16 2. Lake Onalaska showing physiographic details. Stars indicate the locations of feeder channels 1 and 2. Enclosed area between French and Bell Islands represents the approximate location