Developing population density estimates for nine rare Willamette Valley prairie species Prepared by Rebecca Currin, Melissa Carr, and Robert Meinke OREGON DEPARTMENT OF AGRICULTURE for U.S. Fish and Wildlife Service NATIVE PLANT CONSERVATION PROGRAM (Grant No. OR-EP-2, Seg. 17) March 31, 2008 Citation Currin, R., M. Carr and R. Meinke. 2008. Developing population density estimates for nine rare Willamette Valley prairie species. Report prepared for U.S. Fish and Wildlife Service, Region 1, Portland, Oregon. Oregon Department of Agriculture, Salem, Oregon. Acknowledgements As one might imagine, many people contributed to the successful completion of this project. The authors wish to thank the U.S. Fish and Wildlife Service for funding our efforts to increase the body of knowledge available for Oregon’s rare prairie species. Over the course of the last two and a half years, we were lucky to work with many wonderful land owners and managers. In particular, we would like to thank the following people for allowing us access to their little pieces of prairie (and sometimes even going out and collecting data with us!): Tom Franklin and Patricia Farrell (City of Salem); Steve Gisler and Nick Testa (Oregon Department of Transportation); Sally Villagas (Bureau of Land Management, Eugene); Susan Carter (Bureau of Land Management, Roseburg); Kurt Heckeroth (Bureau of Land Management, Salem); Carl Borg (City of Hillsboro); Jason Nuckols, Jason Dumont, Greg Fitzpatrick, and Gil Voss (The Nature Conservancy); Chris Seal and Jock Beall (U.S. Fish and Wildlife Service); Dennis Wiley (Oregon Parks and Recreation Department); David Lebo (U.S. Forest Service, Mt. Hood National Forest); Angie Kempo and Curt Zonick (Metro); Steve DeGhetto (Corvallis Parks and Recreation); Brian Carroll (Linn County Parks and Recreation); Irene Pilgram and Debbie Johnson (Oregon State University); Jeff Mach and Terry Larson (Oregon Military Department); Mike Moore (Oregon Department of Fish and Wildlife); Lynda Boyer (Heritage Seedlings, Inc.); Claire Fiegener (Greenbelt Land Trust); and Mike Robinson, Dave Rand, and Tom Sanak (property owners). In addition to the folks mentioned above, several people went out of their way to show us population locations and share their expertise. We would not have been able to complete the Delphinium leucopheum chapter without the enthusiastic help of Dr. Keith Karoly (Reed College). Dick Brainard of Salix Associates generously shared all of his rare plant survey data for the Muddy Creek (Allan and Allan) property. Sally Villegas provided maps and population data for many sites within the West Eugene Wetlands complex. Chris Seal provided maps and directions for numerous populations within the Central Willamette Valley National Wildlife Refuges. Carolyn Menke and Tom Kaye of the Institute for Applied Ecology cheerfully shared their knowledge of selected prairie species and their populations. Finally, the authors would like to thank the staff and volunteers at ODA’s Native Plant Conservation Program. This project would never have been completed without the hard work, flexibility, and sense of humor exhibited by each person who participated in the field work: Kelly Amsberry, Brian Basor, Melissa Carr, Troy Maddux, Liz Martin, Stephan Meyers, Linda Moore, Ian Silvernail, and Rhiannon Thomas. Although all of the ODA field staff took amazing photos of our study sites and species, special mention must be given to Melissa Carr and Brian Basor for their patience and attention to photographic detail. Linda Moore deserves special recognition for contributing the species background information for the Lathyrus holochlorus chapter. Table of Contents Chapter I. Project Overview .....................................................................................................1 Introduction........................................................................................................................... 1 Study species......................................................................................................................... 1 Study site selection ............................................................................................................... 1 Site selection criteria............................................................................................................. 3 Determining counting unit (what is an individual?) ............................................................. 6 Defining population area....................................................................................................... 7 Overview of site protocol...................................................................................................... 9 Population density methodology overview......................................................................... 10 Issues to address.............................................................................................................. 10 Four general approaches ................................................................................................. 11 Recording site data.......................................................................................................... 15 Analysis........................................................................................................................... 15 Chapter II. Delphinium leucophaeum..................................................................................... 16 Introduction......................................................................................................................... 16 Species information ........................................................................................................ 16 Study sites ....................................................................................................................... 20 Methodology....................................................................................................................... 23 Overview......................................................................................................................... 23 Willamette Narrows........................................................................................................ 23 Willamette Falls.............................................................................................................. 24 Cooper Mountain ............................................................................................................ 25 Camassia Natural Area ................................................................................................... 26 Results................................................................................................................................. 28 Willamette Narrows........................................................................................................ 28 Willamette Falls.............................................................................................................. 28 Cooper Mountain ............................................................................................................ 28 Camassia Natural Area ................................................................................................... 28 Summary......................................................................................................................... 29 Discussion........................................................................................................................... 30 Chapter III. Delphinium pavonaceum..................................................................................... 31 Introduction......................................................................................................................... 31 Species information ........................................................................................................ 31 Study sites ....................................................................................................................... 35 Methodology....................................................................................................................... 38 Overview......................................................................................................................... 38 Decker Road & Highway 34........................................................................................... 38 Buena Vista Road & Davidson Road.............................................................................. 39 Highway 22 (between 99W and Greenwood Road) ....................................................... 39 Finley National Wildlife Refuge..................................................................................... 40 Results................................................................................................................................. 41 Decker Road & Highway 34........................................................................................... 41 Buena Vista Road & Davidson Road.............................................................................. 42 Highway 22 (between 99W and Greenwood Road) ....................................................... 42 Finley National Wildlife Refuge..................................................................................... 42 Summary......................................................................................................................... 42 Discussion..........................................................................................................................