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Strategies for Survival: Ex Situ Plant Conservation - Report of a Research Symposium Held at the Chicago Botanic Garden

Volume 3 Number 3 - December 1999

K. Havens, E. Guerrant & M. Maunder

This autumn, the Chicago Botanic Garden hosted the fourth annual Janet Meakin Poor Research Symposium entitled, Strategies for Survival: Ex Situ Plant Conservation. The symposium was sponsored by Chicago Botanic Garden, U.S.A., Berry Botanic Garden, U.S.A., the Royal Botanic Gardens, Kew U.K. and Center for Plant Conservation, U.S.A. (CPC) with endorsement from Botanic Gardens Conservation International (BGCI).

The symposium was designed to provide a critical review of the realities of ex situ conservation as a scientifically valid, and often undervalued, means for supporting wild populations of threatened species. Over three days a number of important themes were examined:

Strategic Role of Ex Situ Conservation

The role of ex situ methods, within biodiversity management, was reviewed in introductory papers by the conference organisers (Maunder, Havens, and Guerrant). This stressed the diversity of agencies, techniques and objectives (biological and political) that comprise the ex situ constituency. Its supportive role was stressed, ex situ conservation as a means of supporting or reinstating wild populations and habitats through population management, applied research, education and display. The link with habitat restoration was explored by Don Falk of the Society for Ecological Restoration. To complement this strategic approach Holmes Rolston (Colorado State University, U.S.A.) examined the ethics of ex situ conservation and the perceived differences between natural and artificial. Peter Raven of the Missouri Botanical Garden, U.S.A. gave an overview of global plant conservation needs and the role of ex situ methods in his keynote address.

Current Role of Ex Situ

A series of presentations moderated by Brien Meilleur (CPC) demonstrated current and developing applications of ex situ techniques. Peter Wyse Jackson (BGCI) showed the immense investment in ex situ management provided by the world's botanic gardens. Case studies were provided from Australia (Jeanette Mill of the Australian Network for Plant Conservation), Canada (David Galbraith, Canadian Botanical Conservation Network), and Vickie Caraway (Center for Plant Conservation-Hawaii). On a strategic approach, a joint paper by Wendy Strahm (IUCN - the World Conservation Union) and Mike Maunder looked at the IUCN/SSC (IUCN/Species Survival Commission) approach to ex situ conservation using the new Species Survival Commission Plant Conservation Strategy as an example. Roger Smith (Millennium Seed Bank, Royal Botanic Gardens, Kew, U.K.) gave a study on the storage of the U.K. national flora; while Anne Cochrane (Western Australia Department of Conservation and Land Management) showed the role a regional seed bank and research unit attached to a herbarium plays in a model integrated system of rare plant conservation.

To complement a focus on threatened wild species three presentations looked at the ex situ technologies and philosophies utilized for culturally and economically important plant species. Florent Engelman, Jan Engels and Ehsan Dulloo (International Plant Genetic Resources(IPGRI)) discussed new technologies in germplasm conservation and the FAO/IPGRI (Food and Agriculture Organization of the United Nations (FAO) global network for crops. Suzanne Nelson (Native Seed SEARCH, U.S.A.) reviewed initiatives in the communities of southwestern U.S.A. and Mexico for the conservation of traditional native American crops. In contrast, Christina Walters (United States Department of Agriculture National Seed Storage Laboratory (USDA - NSSL) looked at the conservation of crop genetic resources in the U.S.A.

Collection Standards

Day two emphasised the science of ex situ management in terms of harvesting and subsequently managing accessions for planned conservation usage. The genetics of sampling were reviewed by Ed Guerrant and Peggy Fiedler (San Francisco State University, U.S.A.). These built on the widely accepted CPC guidelines from 1991 and developed further criteria for the collection of sample sizes necessary for ex situ collections to fulfil their conservation goals. The impact of seed collection on wild populations was examined by Eric Menges, Samra Hamzé (Archbold Biological Station, U.S.A.), and Ed Guerrant using demographic models of differing harvest regimes and life histories. The relationship between genetic diversity and demography in ex situ facilities was examined by Brian Husband and Leslie Campbell (University of Guelph, Canada), giving particular emphasis to reducing genetic drift, selection and mutational load in ex situ populations. In a study on the application of population genetics to species recovery programmes, Barbara Schaal and Alan Templeton (Washington University, U.S.A.) looked at the issues of geographical differentiation, inbreeding and outbreeding depression. The largely overlooked issue of artificial selection in ex situ collections was reviewed by Kayri Havens, Marlin Bowles (Morton Arboretum, U.S.A.) and R. Stephen Howard (Middle Tennessee State University, U.SA.). Similarly Mike Maunder, Julie Hawkins and Alastair Culham (University of Reading, U.K.) looked at hybridisation in ex situ collections, both the prevalence of accidental hybrids and the problems of conserving natural hybrids!

Storage technologies were given attention, particularly as a means of reducing artificial selection pressures on conventional cultivated collections. A synthesis paper presented by Christina Walters and Hugh Pritchard (Millennium Seed Bank, Royal Botanic Gardens, Kew) looked at the storage biology and storage techniques available for orthodox and recalcitrant seeds. In an extraordinary review paper, Carol Baskin and Jerry Baskin provided a review of available data on seed dormancy behaviour and the implications for cultivation. Papers by Leigh Towill (USDA - NSSL) on pollen storage and Valerie Pence (Cincinnati Zoo and Botanic Garden, U.S.A.) on in vitro propagation of bryophytes pointed to two new avenues for ex situ facilities. Nellie Sugii and Charles Lamoreux of the Lyon Arboretum, Hawaii, U.S.A. showed the practical role of micropropagation in the extinction hot-spot of Hawaii. A paper by Mike Maunder, Stephen Perlman, Paul Cox, and Diane Ragone (National Tropical Botanic Garden, Hawaii, U.S.A.) looked at the application of horticultural ex situ techniques to wild and semi-managed populations as a form of cost effective management in high diversity areas.

The third day was spent in working groups looking at the practicalities of ex situ conservation, particularly the importance of dealing with project partners and clients; the funding of ex situ conservation and the development of the appropriate staff skills. The conference brought together a wide variety of practitioners and researchers to examine the limitations of ex situ conservation (scientific and political) and realistically identify where it can make a valid contribution to reversing biological loss and extinctions.

The three main tasks of ex situ conservation are 1) to collect genetically representative samples, 2) maintain them off site in good condition for a long period of time, and 3) ultimately, be able to use stored samples to establish new, or augment existing populations. The first and third tasks were the subjects of previous CPC-sponsored conferences, and the information later published in two highly regarded books, Genetics and Conservation of Rare Plants (Falk and Holsinger (eds.), 1991) and Restoring Diversity: Strategies for the Reintroduction of Endangered Plants (Falk, Millar and Olwell (eds.), 1996) respectively. This conference and volume were designed to join the first two into a logical trilogy, which will provide a comprehensive overview of the field of ex situ plant conservation.