Introduction

JOYCE MASCHINSKI AND KRISTIN E. HASKINS

In the face of mounting numbers of plant species at risk of extinction (Gilbert 2010), increasing rates of habitat destruction, spreading invasive species, and effects of climate change (Tilman and Lehman 2001; Walther et al. 2002; Karl and Trenberth 2003), there is a great need for urgent action to preserve species before they are extirpated. This book tells a story of the good fight to save and restore some of the rarest plant species in the world. The story is a complicated but hopeful one.

The practice of plant reintroduction is preceded by many other activities. They include documenting rare species' current distributions, gathering seeds and propagules from living plants for ex situ collections, and researching species' biology and threats. In the best circumstances conservation practitioners work in tandem with land managers and the public to restore healthy, wild habitats and populations of rare species. But has plant reintroduction worked as a conservation tool? And how have plant reintroductions contributed to reintroduction science and practice?

For two decades, responsible agencies have promoted using reintroduction as a recovery strategy for endangered plant species (e.g., US Fish and Wildlife Service 1999). It is considered an essential worldwide conservation tool, and the efficacy of this conservation strategy for animals has been reviewed recently (Fischer and Lindenmayer 2000; Seddon et al. 2007), but such a critical review of plant reintroductions had not been done at the time we began writing this volume (but see Godefroid et al. 2011). A review of plant reintroductions is paramount because plant management techniques are fundamentally different from those used for animals. Herein we take stock of our progress with reintroduction in an effort to facilitate the wise decisions needed to preserve future biodiversity.

As one of the national leaders in plant conservation, the Center for Plant Conservation (CPC) and its thirty-six participating institutions are devoted to preventing extinction and achieving recovery for imperiled plants native to the United States of America. Working with land managers and the public, CPC conservation officers actively secure seed and living ex situ collections and monitor, research, and restore rare species populations in the wild. Collectively they have conducted nearly 200 reintroductions throughout the United States in the last 20 years.

Fifteen years ago, CPC published Restoring Diversity with Island Press (Falk et al. 1996), which encapsulated the contemporary understanding of plant reintroductions from both political and biological perspectives. It provided a set of guidelines intended to help practitioners implement plant reintroductions. Since its publication, knowledge of the practice of restoring endangered plants has increased exponentially. This volume presents a comprehensive review of reintroduction projects and practices, the circumstances of their successes or failures, the lessons learned, and the potential role for reintroductions in preserving species threatened by climate change. These findings culminate in a revised set of guidelines for best reintroduction practice.

To assess the current status of plant reintroductions worldwide and to gain a broad sample of reintroduction circumstances, CPC initiated a multipronged approach: a web-based registry, a symposium, and this volume. The extensive CPC International Reintroduction Registry, launched in the spring of 2009, aimed to document published and unpublished reintroductions. In fall 2009, the international symposium "Evaluating Plant Reintroductions as a Plant Conservation Strategy: Two Decades of Evidence" convened in Saint Louis, Missouri. Oral presentations by plant reintroduction experts formed the basis of this volume. Attended by government personnel responsible for implementing the Endangered Species Act, environmental consultants, academicians, and botanical garden scientists, the symposium served as a focal event to review plant reintroduction practice and science. Participants provided suggestions for CPC Best Reintroduction Practice Guidelines and made recommendations for future directions pertaining to managed relocation (MR). This volume, organized in four parts, represents the ideas discussed at the symposium, often with passion and commitment but with good stewardship of biodiversity foremost in mind. It is noteworthy that the contributors to this volume represent professional conservationists with first-hand reintroduction experience working in government agencies and botanical gardens around the world.

Part I comprises two reviews of plant reintroductions conducted independently. Guerrant (chap. 2) presents a general overview of the database projects reported in the CPC International Reintroduction Registry. He typifies the nature and attributes of reintroduction projects, which is an essential first step for identifying information gaps. In an independent and rigorous meta-analysis of a different set of reintroductions, Dalrymple and colleagues (chap. 3) assess the efficacy of reintroductions for establishing sustainable...