Fitness effects of and outbreeding on golden paintbrush (Castilleja levisecta): Implications for recovery and reintroduction

September 2003

Thomas N. Kaye Beth Lawrence

Institute for Applied Ecology Corvallis, Oregon

Washington Department of Natural Resources and Institute for Applied Ecology PREFACE

This report is the result research conducted by the Institute for Applied Ecology (IAE) under contract with a public agency, the Washington Department of Natural Resources, Natural heritage Program under Contract No. 03-218. IAE is a non-profit organization dedicated to natural resource conservation, research, and education. Our aim is to provide a service to public and private agencies and individuals by developing and communicating information on ecosystems, species, and effective management strategies and by conducting research, monitoring, and experiments. IAE offers educational opportunities through 3-4 month internships. Our current activities are concentrated on rare and endangered plants, habitat management and invasive species.

Questions regarding this report or IAE should be directed to:

Thomas N. Kaye Institute for Applied Ecology 227 SW 6th Corvallis, Oregon 97333

phone: 541-753-3099 fax: 541-753-3098

ACKNOWLEDGMENTS

Funding for this project was provided by the Washington Department of Natural Resources and Institute for Applied Ecology. We thank the Oregon State University Seed Lab and Dale Brown for providing germination assistance and facilities used in this study. We also thank Melissa Carr, Emerin Hatfield, Rebecca Kessler, Melanie Barnes, and Angela Brandt (IAE/Native Plant Society of Oregon Interns) for assistance with plant propagation and data collection. Manuela Huso provided generous and invaluable statistical support and assistance. We thank Florence Caplow and Carla Wise for their discussions and comments on an earlier draft of this report.

Inbreeding and outbreeding in Castilleja levisecta, 2003 i TABLE OF CONTENTS

Preface i

Acknowledgments i

Introduction 1 Background 1 The importance of mating system: inbreeding and outbreeding 1

Methods 4 Pollination experiment 4 Propagation of crossed progeny 6 Analysis of fitness measures 6

Results 8 Effects of inbreeding and outbreeding on fitness 8

Discussion 11 Mating system of Castilleja levisecta 11 Effects of inbreeding and outbreeding on fitness 11 Recommendations for recovery and reintroduction 14

Literature cited 16

Inbreeding and outbreeding in Castilleja levisecta, 2003 ii INTRODUCTION

Background

Castilleja levisecta (golden paintbrush) once occupied prairies and grasslands throughout the Puget Trough and Willamette Valley. Habitat destruction and alteration over the past century have resulted in substantial declines in native vegetation in this ecoregion, and several species, including golden paintbrush, are now listed by state and federal agencies as threatened or endangered. All remaining Figure 1. Castilleja levisecta (golden paintbrush). populations of golden paintbrush occur in Washington and British Columbia; the species is considered to be extirpated in Oregon.

Castilleja levisecta is an herbaceous perennial that appears to reproduce only by seed. Many populations are declining, and past research indicates that disturbances such as fire and mowing may be useful for maintaining or expanding existing populations (USFWS 2000). Like most paintbrushes (Heckard 1962), this species is a hemiparasite – its roots penetrate the roots of neighboring plant species and derive nutrients, carbohydrates, and possibly other secondary compounds from these hosts.

The Recovery Plan for golden paintbrush (USFWS 2000) identifies population reintroduction, development of propagation methods, and studies of the pollination of the species as high priority actions to meet recovery objectives. Because no populations of this speci