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Mar 19, 2012 - 3. Germination results for Iris tenax with 2 and 4 week warm stratification. ...... oreganus seeds were broadcast in one 0.5 x 0.5 m plot in each treatment ...... 5.5 57.5. 63. 40.5. 0. 0.5. 0.6. 5. 1.8. BF. 20. L yes. 4.5 66. 70.5. 13.5. 1.

AN ABSTRACT OF THE THESIS OF Katherine D. Jones for the degree of Master of Science in Botany and Plant Pathology presented on March 19, 2012.

Title: Factors Affecting Establishment and Germination of Upland Prairie Species of Conservation Concern in the Willamette Valley, Oregon

Abstract approved:

___________________________________________________________ Thomas N. Kaye

Identifying mechanisms that determine who lives and dies is the first step in developing successful restoration techniques for rare species and endangered habitats. We studied interactions that affect establishment of native plant forbs of conservation concern at the seedling stage to support the theoretical basis for restoration activities in Pacific Northwest prairies. Specifically, we tested the hypothesis that seedling establishment is controlled by 1) competition with or 2) facilitation by existing vegetation and that the interaction is mediated in part by environmental stress. We direct-seeded or planted vegetative plugs of Lupinus oreganus, Castilleja levisecta, Erigeron decumbens, Iris tenax and Sidalcea malviflora ssp. virgata into 20 plots with a range of community compositions in high-stress upland prairies at each of three sites. We counted seedlings and estimated cover of plant functional groups as well as litter, bare soil and disturbance then used linear regression to test for effects of these factors on seedling establishment. We found evidence of indirect facilitation of grass on seedling establishment in the first year: higher accumulations of leaf litter increased seedling numbers at two sites. In the second year, there was evidence of facilitation by live vegetation and

litter on seedlings at one site, but no net effect of either competition or facilitation at the other two sites. Overall, we found more evidence for positive interactions than we did for competition. In particular, litter appeared to have a positive effect on seedling establishment of L. oreganus and S. malviflora ssp. virgata. This is contrary to the common perception that litter inhibits plant establishment but supports the theory that facilitation is more common in high stress sites; practitioners should consider seeding into leaf litter at some sites. To support a robust approach to conservation and reintroduction of species with dormant seed, we characterized dormancy types and developed germination protocols for S. malviflora ssp. virgata and I. tenax. S. malviflora ssp. virgata has physical dormancy and may have physiological dormancy. Scarification followed by four weeks of cold moist stratification was effective in initiating germination. I. tenax has morphophysiological dormancy which is overcome by four weeks of warm moist stratification followed by 6-12 weeks of cold stratification. We also conducted a metaanalysis of experiments that tested pre-sowing seed scarification of L. oreganus and conclude that breaking physical dormancy prior to direct seeding does not support higher establishment relative to unscarified seeds in this species.

©Copyright by Katherine D. Jones March 19, 2012 All Rights Reserved

Factors Affecting Establishment and Germination of Upland Prairie Species of Conservation Concern in the Willamette Valley, Oregon

by Katherine D. Jones

A THESIS submitted to Oregon State University

in partial fulfillment of the requirements for the degree of

Master of Science

Presented March 19, 2012 Commencement June 2012

Master of Science thesis of Katherine D. Jones presented on March 19, 2012.

APPROVED:

___________________________________________________________ Major Professor, representing Botany and Plant Pathology

___________________________________________________________ Chair of the Department of Botany and Plant Pathology

___________________________________________________________ Dean of the Graduate School

I understand that my thesis will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my thesis to any reader upon request.

___________________________________________________________ Katherine D. Jones, Author

ACKNOWLEDGEMENTS They say, ‘it takes a village to raise a child;’ I believe the same may be said of a graduate student. Leading that effort for me was my adviser Tom Kaye. His passion for rare species conservation is truly infectious and his ability to laugh at adversity helped me accept demonic intrusion as a part of the scientific process. He is the type of ecologist I hope to be, thank you. I’d like to thank my co-adviser Aaron Liston, who was instrumental familiarizing me with the local flora and helping me develop as a teacher, and committee member Dave Pyke who was always available to chat about sticking points in my research. Michael Huber joined the committee at the last moment and gave me the few extra days that made all the difference. I am thankful to Mark Wilson for asking hard question and teaching me to think like an ecologist. I’d like to thank my lab mates Andrea Thorpe and Katie Gallagher who I frequently relied on for moral support and logistical feedback and my lab mate Ian Pfingsten for sharing his statistical prowess. I’d like to thank all of the people who provided materials, data and specific knowledge for this thesis, Lynda Boyer, Carol Baskin, Jon Anderson, Angela Rose, Jock Beall, Paul Severns, everyone at the Institute for Applied Ecology. I’d especially like to thank Sabry Elias who opened the OSU Seed Lab to me well after closing time. I was fortunate to have a solid group of devoted undergrads, Jared, Amanda, Bryce, Max, Liz, Brad, Dan, Bruce, Natassia, Sam, Brent and Melissa without whom all these seedlings would not have been counted. I’d like to thank all the organizations that supported me financially, the BPP, the BPP Graduate Student Association, the Willamette Chapter of the NPSO, CTD, AICF, AIGC and AISES. All of my friends at BPP and OSU helped me in so many ways – Miriah, Silia, Erin, Peter, Sara, Laura, and many more, thank you. Thank you to my family for encouraging me to follow my heart, though it doesn’t always make sense and my wonderful husband Oliver who, throughout everything, has been there not only holding my hand and helping me stay sane, but counting and scarifying seeds. I could not have done it without him.

TABLE OF CONTENTS Page Chapter 1: Restoration of species of conservation concern in an ecosystem context .....1 Study System .............................................................................................................. 2 Umbrella Species ....................................................................................................... 3 Research Approach .................................................................................................... 5 References .................................................................................................................. 6 Chapter 2: Ecological Drivers of Seedling Establishment and Survival ......................10 Abstract .................................................................................................................... 11 Introduction .............................................................................................................. 11 Methods .................................................................................................................... 15 Results ...................................................................................................................... 23 Discussion ................................................................................................................ 33 References ................................................................................................................ 39 Chapter 3: Sprouting seeds to save butterflies: Characterizing dormancy of two perennial plant species of conservation concern .......................................................... 47 Abstract .................................................................................................................... 48 Introduction .............................................................................................................. 48 Methods .................................................................................................................... 50 Results ...................................................................................................................... 57 Discussion ................................................................................................................ 62 References ................................................................................................................ 66 Chapter 4: Do seed enhancements promote establishment of direct seeded native species? A meta-analysis on a physically dormant threatened forb ............................ 69 Abstract .................................................................................................................... 70 Introduction .............................................................................................................. 70 Methods .................................................................................................................... 72 Results ...................................................................................................................... 79 Discussion ................................................................................................................ 81 References ................................................................................................................ 82

TABLE OF CONTENTS (continued) Page Chapter 5 : General Conclusion ....................................................................................88 Future research directions ........................................................................................ 89 References ................................................................................................................ 91 Bibliography .................................................................................................................92 APPENDICES ............................................................................................................107 Appendix A: Supplemental material to Chapter 2 ......................................................107 Plot Layout ............................................................................................................. 108 Sampling ................................................................................................................ 110 Cover estimates ...................................................................................................... 111 Cryptic Seedlings ................................................................................................... 113 Results .................................................................................................................... 115 Appendix B: Supplemental material to Chapter 3 ......................................................133 Iris tenax seed coat ................................................................................................. 134 Germination trials................................................................................................... 136 Morphological dormancy in Iris tenax................................................................... 139 Iris tenax field trials ............................................................................................... 139 Appendix C: Supplemental material to Chapter 4 ......................................................142 Seedling mortality .................................................................................................. 143 Meta-analysis raw data ........................................................................................... 145

LIST OF FIGURES

Figure

Page

Chapter 2 1.

IAE/TNC research sites, ours are the southernmost sites, Pigeon Bute (PB), Bellfountain (BF) and Ft. Hoskins (FH) ...................................................... 19

2.

Litter depth compared with grass cover (p