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Botanic gardens in the age of restoration

Volume 6 Number 1 - January 2009
Kingsley Dixon and Suzanne Sharrock

Introduction

Storm Cunningham’s latest book, provocatively entitled reWealth (McGrawHill), presents global restoration as a $2 trillion global industry. His mantra is that we can no longer exploit the planet in the belief that there is an inexhaustible supply of natural resources and that restoration of our natural capital assets (as well as the built and social capital of human societies) is critical if the planet is to be sustained. The question remains as to just how well botanic gardens are seizing the opportunity to be an effective and integral part of the global restoration challenge?

Building a common vision

For the past three decades or so, botanic gardens have been on a journey of discovery. The journey was a response to a world call-to-arms based on the pollution scares of the 1970’s (the scene was set by Rachel Carson’s Silent Spring) followed by the dire predictions of a global biodiversity melt-down and the Rio Summit in 1992, which culminated in the establishment of the Convention on Biological Diversity (CBD). While the CBD committed countries to conserve their biodiversity, it was still several years before a specific plan for conserving plant diversity at the global level emerged. Following concerted action by the world’s leading botanists, the Global Strategy for Plant Conservation (GSPC) was adopted by the Parties to the CBD in April 2002, strengthening botanic gardens connections globally. The GSPC includes 16 outcome-oriented targets to be met by 2010 and Target 8 focuses on ex situ conservation and restoration. This target provided botanic gardens for the first time with a united vision – avert plant extinction through ex situ conservation. Seedbanks, tissue culture, cryogenics and DNA fingerprinting emerged as charismatic technologies employed to save species.

GSPC Target 8: 60 per cent of threatened plant species in accessible ex situ collections, preferably in the country of origin, and 10 per cent of them included in recovery and restoration programmes.

Today, the world’s 2,500 botanic gardens have assembled a formidable scientific armoury in the fight against extinction. The scientific capacity of botanic gardens through such initiatives as the Millennium Seedbank Project has meant that ‘…there is no technological reason why any species need go extinct’ (Paul Smith, Head, Millennium Seed Bank Project). Through their living collections and seedbanks, the world’s botanic gardens and arboreta conserve a vast number of plant species. In an attempt to monitor progress towards Target 8, in 2004 BGCI launched its PlantSearch database, which provides information on plants in cultivation in botanic gardens, and links this information to threatened plant databases. At least 12,000 globally threatened species are maintained in botanic garden collections and some 100 plant species are now only found in botanic gardens! But where to next? Do seedbanks or artificially maintained populations in a botanic garden constitute conservation or do botanic gardens need to collectively take the next step in the conservation journey and restore species and habitats? If Target 8 of the GSPC is to be achieved, the answer is clearly the latter.

The restoration challenge

Although reintroduction of threatened species in the wild has so far been relatively restricted, recovery of wild populations of depleted species may be increasingly important in repairing damaged ecosystems and restoring connectivity at a landscape scale. However, for many of the world’s threatened species, repatriation to nature is just not an option. With 60% of the land area of the planet now disturbed by humans, we can no longer rely on finding suitable and naturally resilient wild locations for all species; such areas just don’t exist. For example, of the 2,814 conservation species in Western Australia (double the flora of the United Kingdom), at least half exist in highly disturbed habitats where invasive species, disease (particularly Phytophthora), salinity and pests mean that the critical ecological equilibrium needed to support long-term, self-perpetuating populations is not in place. Similar scenarios are now being played out in many countries.

The conservation mantra is therefore turning towards how habitats can be rebuilt, revitalised and restored, heralding a new era and new opportunities for botanic gardens as ‘restoration hubs’. Restoration is inextricably tied to the global conservation challenge. Restoration takes a dysfunctional ecosystem and returns it to health and ecological equilibrium as a dynamic component of the conservation picture. In Cunningham’s words, ‘..restoration.. takes a dying, useless or ugly asset and returns it to health, value and beauty..’ What better ideal for botanic gardens than to engage in the reclamation of abandoned and seemingly ‘useless’ land while providing the ecological framework for repatriation of species. With over 200 million visitors annually, the capacity for botanic gardens to link active restoration to awareness within communities presents new opportunities for focusing education and extension programmes.

Restoration in a time of climate change

Climate change introduces an added complexity to ecosystem restoration. It is no longer ‘simply’ a question of restoring an ecosystem to its previous state by the reintroduction of species, but in the face of a changing climate, new species assemblages may also need to be considered. Restoration activities will also need to take into account the migration needs of plant species as they attempt to move into new climatically secure, safe havens. In ancient, stable floras such as those found in South Africa and temperate southwestern Australia, the prospect is particularly daunting as new research shows that many major plant groups lack capacity for long-distance, short-time frame dispersal. Iconic plants, such as Banksia, face the prospect of dwindling populations unable to effectively migrate to safe-sites by the 2050 date when climate change is expected to spell the end for a third or more of the world’s plant species (Thomas et al. 2004; Fitzpatrick et al. 2008). For many plant species therefore, in today’s highly fragmented and developed landscapes, assisted migration (see Box 1) may be the only way to secure species in environments where there will be some hope of sustaining populations outside of their ‘protective custody’ environments in botanic gardens.

 

Box 1: Assisted migration

Assisted migration, or the establishment of plant species or communities in areas not presently within their ‘native’ ranges, is a contentious issue that places different conservation objectives at odds with one another. There are numerous examples where moving species beyond their current range into natural and agricultural landscapes has had significant negative consequences. However, the growing threat of biodiversity loss due to climate change means that if preventing climate-driven extinction is a conservation priority, assisted migration must be considered an option. Botanic gardens are well placed to contribute to the debate, which should include assessments of potential benefits and risks using lessons from natural succession dynamics, experimental introductions and restoration ecology.

Issues that will need to need taken into account include:

  • The need for basic current distribution data;
  • The accuracy of predicted future distribution based on modelling;
  • The importance of community / inter-species interactions;
  • Extent and type of intraspecific diversity in the source population;
  • Potential for invasiveness in the new habitat.

The role of botanic gardens

Restoration ecology, the science of restoration, is an emerging and energetic discipline that brings into focus and play, an array of conceptual and technological tools. For botanic gardens, these tools represent challenges and opportunities to cross-cut science and operational areas for creating a ‘one-stop-shop’ in restoration. For example, botanic gardens invest substantially in horticultural science with living collections that represent many years of research and trial and error in developing horticultural excellence. Linking this capacity with the other research capacities in botanic gardens represent a unique opportunity for complimentary up-skilling for restoration activities. Few other organisations are so equipped to deliver such a potent combination of skills and ability linked to a strong and vibrant horticultural heritage.

Furthermore, the worldwide network of botanic gardens together holds a wealth of information and experience on cultivating plant species in different environments. In the face of rapid climate change, exchange of such information will be invaluable in developing efficient and sustainable restoration programmes. In support of this, BGCI has developed two new modules for its PlantSearch database, which will allow botanic gardens to share information on propagation methodologies and restoration efforts on a species-by-species basis. At present these modules consist of a set of internal web pages on the BGCI website and a desktop application that allows institutions to enter data without being connected to the internet. A working prototype will be developed following consultation with BGCI member gardens around the world and agreed initial data entry will be undertaken for Magnolia, Acer, Quercus and Rhododendron and for threatened plants of Russia. Information collected through this data entry will be used to provide case studies to plan the development of a manual on the restoration of endangered tree species.

Conclusion

Although important players in the global restoration challenge, it is clear that botanic gardens will not be able to tackle this alone. Restoration of nature has been aspired to for generations. The seamless transition from conservation to restoration as witnessed from the middle of the 20th century with the calls of Aldo Leopold (Sand County Almanac) to protect nature and natural resources (“A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise”) to the ascendancy of the restoration ethic we see today in such books as reWealth, call upon integration – at the scientific, cultural/social, economic and political levels. For botanic gardens, linking within and beyond our institutional boundaries to embrace broader scientific, economic and social agendas will be fundamental for ensuring botanic gardens use their formidable capacity to deliver broadscale benefits in species and ecosystem restoration.

References

Thomas, C.D., Cameron, A., Green, R.E., Bakkenes, M., Beaumont, L.J., Collingham, Y.C. et al. 2004. Extinction risk from climate change. Nature, 427, 145–147.

Fitzpatrick, M.C., Gove, A.D., Sander, N.J. and Dunn, R.R. 2008. Climate change, plant migration, and range collapse in a global biodiversity hotspot: the Banksia (Proteaceae) of Western Australia. Global Change Biology, 14(6): 1337-1352.

Kingsley Dixon
Director Science,
Kings Park and Botanic Garden,
West Perth, 6005,
Western Australian;
Visiting Professor,
The University of Western Australia.
Email: kdixon@bgpa.wa.gov.au

Suzanne Sharrock
Director of Global Programmes
BGCI
Descanso House
199 Kew Road
Richmond TW9 3BW
UK
Email: Suzanne.sharrock@bgci.org