AN ABSTRACT OF THE THESIS OF James Douglas Ripley for the degree of Doctor ofPhilosophy in Botany and Plant Pathology presented on December 14,1983. Title: Description of the Plant Communities andSuccession of the Oregon Coastal Grasslands Redacted for privacy Abstract approved: William W. Chilcote In an effort to describe the plantcommunities and succession of the Oregon coastal grasslands,vegetation and environmental data were collected from75 stands at 24 separate locations ranging from CapeFalcon in Tilla- mook County to Cape Ferrelo in Curry County. The vegeta- tion data consisted of cover and frequency valuesfor vascular plants and the environmental dataincluded wind and salt spray exposure measurements,slope, aspect and a variety of soil properties. The vascular flora encounteredconsisted of 249 specific and intraspecific native and introducedtaxa representing 166 genera and 55 families. An annotated catalogue of the flora was prepared. The vegetation data were analyzed using detrended correspondence analysis (DCA) and the TWINSPAN cluster- ing program. These multivariate analyses served as the basis for the classification of the vegetation into seven community types (Carex obnupta,Calamagrostis nutkaensis/Elymus glaucus, Heracleum lanatum/Vicia gigantea, Lomatium martindalei/Koeleria cristata, Danthonia californica/Aira caryophyllea, Holcuslanatus/ Anthoxanthum odoratum and Fragaria chiloensis/Armeria maritima). Using correlations of the DCA scores with environ- mental variables, the first DCA axis was interpreted as representing a moisture gradient while the second DCA axis was interpreted as representing a latitudinal gradient. Vegetation data were collected from paired transects on grazed and ungrazed grasslands alongfence lines in an effort to determine compositional changes withgrazing. It was concluded that grazing led to a decreasein shrub cover and substantial increases inthe number and cover of annual taxa. Documentation of successional changes in thegrassland vegetation was obtained from historical written accounts and photographs. It was concluded that the Oregoncoastal grasslands are undergoing a succession to shruband tree dominated communities due largely to theexclusion of fire. Description of the Plant Communities and Succession of the Oregon Coast Grasslands by James Douglas Ripley A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Completed December 14, 1983 Commencement June 1984 APPROVED: Redacted for privacy PipTessor of Botany in charge-of major Redacted for privacy Head of the Department of Botany and Plant Pathology Redacted for privacy Dean of Grad e School] (7 Date thesis is presented December 14, 1983 Typed by Express Typing Services for James DouglasRipley ACKNOWLEDGEMENTS As an Air Force officer and member of the faculty of the U. S. Air Force Academy, my participation in this grad- uate program was made possible through the generous support of an Air Force Institute of Technology Civilian Institution Scholarship. I wish to acknowledge my profound debt to the Air Force for providing me with this wonderful opportunity and I would like to particularly thank Colonel Orwin Sampson, Permanent Professor and Head, Department ofBiology, U. S. Air Force Academy, for his role in my obtainingthe scholarship. Lieutenant Colonel John I. Kitch, Jr., Chief of the Air Force Institute of Technology CivilianInstitution Programs was most helpful with administrative andlogistical matters during my studies. To my major professor, Dr. William W. Chilcote,I am deeply grateful for his sympathetic and wise guidance,for suggesting the subject of my research, and for hissincere friendship. I would also like to thank the othermembers of my graduate committee, Professors Kenton L.Chambers, Garvin D. Crabtree, Robert E. Frenkel and Gerald H.Simonson, for their guidance and support. The field assistance pro- vided by Professors Simonson and Frenkel was particularly helpful as was Dr. Frenkel's considerable individual guidance during the analysis of my field data. Members of the Department of Botany and PlantPathology whom I would like to individually thank for their courtesy and help during my graduate studies include Dr. Thomas C. Moore, Dr. Donald B. Zobel and Ms. Leona Nicholson. I am also indebted to Mrs. La Rea Dennis Johnston for herfriend- ship and conscientious help with the identification of my plant specimens. Professor C. David McIntire, both through his excellent course and individual guidance,provided me with invaluable assistance in the multivariateanalysis phase of this study. One of the distinct pleasures of my stayat Oregon State University has been the friendships Ihave made with a number of graduate students. To my good friend and office mate Joseph Antos, I would like to express mysincere gratitude for his constant encouragement,stimulating dis- cussions and general willingness to helpwith anything that needed doing. I thank Glenn Stewart for hisalways cheerful help and for providing a most valuable NewZealand perspective to my study of ecology. Bradley G. Smith's generous and patient sharing ofhis vast knowledge of com- puters and the multivariate analysisof ecological data was a great help. Other graduate students whosevaluable advice I sought included Charles Halpern, TeresaMagee and Billy Snow. Mr. John Wade of the Oregon StateUniversity Depart- ment of Atmospheric Sciences providedmuch useful climatic data. I thank also Professor Stephen DowBeckham of the History Department, Lewis and Clark College,for suggesting many historical references concerningthe coastal Indians of Oregon. Members of the Soil Conservation Servicewho generously reviewed my soil descriptions andprovided other help included Mr. John Haagen (Curry County), Mr.Richard Patching (Lincoln County) and Mr. Philip Smith(Tillamook County). The computer analysis of my field data wasmade possible through an unsponsored research grantprovided by the Oregon State University Computer Centerwhich I would like to gratefully acknowledge. Finally, I wish to acknowledge the roleof my wife Arlene, who throughout this adventure hasprovided the love, help, encouragement and understandingthat has made it all seem worthwhile. TABLE OF CONTENTS INTRODUCTION 1 LITERATURE REVIEW 4 DESCRIPTION OF THE STUDY AREA 22 General 22 Vegetation 24 Fauna 27 Climate 29 Temperature 30 Precipitation 37 Humidity, Cloud , and Fog 38 Wind 38 Topography and Geology 44 Soils 51 History 54 METHODS 60 Vegetation Description and Classification 60 Reconnaissance 60 Sampling Methods 61 Plant Identification, Nomenclature, and Documentation 64 Assessment of Environmental Variables 65 Wind 65 Salt Spray Exposure 66 Aspect and Moisture Index 67 Slope, Latitude, Mulch Thickness, and Bare Soil and Rock Coverage 68 Soil 69 Grazing 70 Succession 70 Analytical Procedures 72 Data Editing 73 Classification 75 Ordination 76 Constancy, Mean Percent Cover, and Richness 78 Correlations 78 RESULTS AND INTERPRETATION 79 Stand Selection 79 Floristic Analysis 79 Environmental Variables 85 Soils 85 Topography, Wind, Moisture, Mulch Thickness, and Coverage of Soil and Rock 87 Correlations of Environmental Variables 87 Grazing 93 Constancy, Mean Percent Cover, and Richness 103 Community Classification 105 Description of Communities 107 The Carex obnupta Community 109 The Calamagrostis nutkaensis/Elymus glaucus Community 114 The Heracleum lanatum/Vicia gigantea Community 116 The Lomatium martindalei/Koeleria cristata Community 118 The Danthonia californica/Aira caryophyllea Community 121 The Holcus lanatus/Anthroxanthum odoratum Community 123 The Fragaria chiIoensis/Armeria maritima Community 125 Ordination 129 Sample Ordinations 129 Species Ordinations 132 Environmental Variables 135 Succession 149 Successional Status of the Individual Communities 149 Historical Observations 152 Cape Falcon 152 Neahkahnie Mountain 152 Maxwell Point, Oceanside 153 Cascade Head 153 Cape Foulweather 159 Yaquina Head 161 Central Coast (Yachats to Heceta Head) 161 Cape Blanco 170 Humbug Mountain 170 DISCUSSION 172 Floristic Composition of the Oregon Coastal Grasslands 172 Environmental Variables 174 Soils 175 Mulch Layer 178 Wind and Salt Spray Exposure 179 Grazing 180 Community Classification and Ordination 181 Individual Communities 181 Analysis of Ordination Axes 184 Succession 186 BIBLIOGRAPHY 190 APPENDICES 203 APPENDIX 1 - Annotated Catalogue of the Flora 203 APPENDIX 2 - Legal and Geographic Locations of Study Sites 222 APPENDIX 3 - Summary of Soil Properties 224 APPENDIX 4 - Representative Soil Profiles227 APPENDIX 5 - Summary of Site Environ- mental Factors 233 LIST OF FIGURES Figure Page 1. Location of sampling areas 80 2. Total taxa on grazed and ungrazed transects at Yaquina Head and Humbug Mountain 97 3. Perennial taxa on grazed and ungrazed tran- sects at Yaquina Head and Humbug Mountain 97 4. Biennial taxa on grazed and ungrazed tran- sects at Yaquina Head and Humbug Mountain 98 5. Annual taxa on grazed and ungrazed transects at Yaquina Head and Humbug Mountain 98 6. Native taxa on grazed and ungrazed transects at Yaquina Head and Humbug Mountain 99 7. Introduced taxa on grazed and ungrazed transects at Yaquina Head and Humbug Mountain 99 8. Forbs on grazed and ungrazed transects at Yaquina Head and Humbug Mountain 100 9. Grasses on grazed and ungrazed transects at Yaquina Head and Humbug Mountain 100 10. Ferns on grazed and ungrazed transects at Yaquina Head and Humbug Mountain 101 11. Shrubs on grazed and ungrazed transects