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Australasian Plant Conservation

Originally published in Australasian Plant Conservation 15(2), September - November 2006

From the Editor: introducing 'Conserving Symbioses'

Tom May
Co-ordinator, Editorial Team, Australasian Plant Conservation, Royal Botanic Gardens Melbourne

Partnerships between scientists and land managers or community groups and government are of great importance these days in conservation. Partnerships in nature have been around for millennia, and indeed were probably crucial for significant events in evolution, such as the move of plants onto land.

There is an intricate web of inter-connections between plants and other organisms. These symbioses may benefit both partners (in which case the relationship is called a mutualism), or one partner may benefit but the other not be affected for better or worse, or sometimes one partner benefits and the other incurs some detriment. Organisms involved in symbioses often absolutely rely on the relationship for their survival and reproduction.

The focus of conservation efforts is too often solely on particular plants or animals. The purpose of the 'Conserving Symbioses' theme is to draw attention to symbiotic relationships, because conservation of one organism may depend on an understanding of links with other organisms.

Examples of essential plant symbioses are relationships with pollinators and seed dispersers. Mycorrhizas (literally 'fungus-roots') between plants and fungi are another symbiotic relationship, which is not only out of sight below ground, but also an often overlooked aspect of the biology and ecology of plant and fungus.

Most articles in this issue focus on mycorrhizal relationships between orchids and fungi. The prominence of orchids is not surprising, due to the many rare and endangered species, and their reliance on fungi for germination. Nevertheless, it is worth keeping in mind that most Australian plants (with a few notable exceptions such as in the Proteaceae) are mycorrhizal.

In the opening article, Mark Brundrett provides an overview of the 'Role of symbiotic relationships in Australian terrestrial orchid conservation', covering relationships with both mycorrhizal fungi and insect pollinators. The fascinating connections between orchids and pollinators, such as thynnid wasps, are also mentioned in the review (p. 26) by Katrina Syme of a new book about the flora of the Otway region of Victoria
(see cover illustration).

John Dearnaley and Andrew Le Brocque discuss the different kinds of fungi that are involved in orchid mycorrhizas, noting the advances made possible in identification of the fungi by molecular biology techniques. Emily McQualter and co-authors focus on the fungi associated with Prasophyllum. A most intriguing finding is that fungi isolated from adult orchid plants are not always effective at germinating seed of the same orchid species.

Magali Wright and co-authors detail the contributions of Royal Botanic Gardens Melbourne to Victorian orchid conservation, highlighting a symbiotic approach which includes hosting of an Australia-wide Cooperative Orchid Conservation website. Presentations at the recent International Conference on Mycorrhiza, held in Granada, Spain, are reviewed by Zoe Smith, who mentions many exciting advances, including the first complete DNA sequencing of a mycorrhizal fungus (a species of Laccaria).

Given the undoubted importance of fungi as mycorrhizas in Australian ecosystems, and for iconic Australian plants such as eucalypts and casuarinas, there are remarkably few published scientific studies about mycorrhizas in revegetation. Jacqui Stol and Jim Trappe report on a ground-breaking study which indicates that the mycorrhizal fungi associated with woodland trees disappear from adjacent cleared paddocks. They also assessed the efficacy of different forms of mycorrhizal inoculation on outplanted tubestock, and found that some inoculated fungi failed to form mycorrhizas under the potting mix and watering regime that they used. There is a great interest in using fungi for revegetation (a common question is "where do I buy the fungi") but there is a great deal more to learn before standard protocols can be recommended.

There are numerous other symbioses that do not involve fungi and orchids! The article from Anne Cochrane and co-authors is a reminder of other ways that plants rely on animals. The authors demonstrate that ingestion by small mammals of seeds of Billardiera fusiformis enhanced germination; they also discuss the potential for ingestion to aid dispersal.

Articles not on the particular theme of each Australasian Plant Conservation are always welcome, and the final two articles feature a report from Kimberlie Rawlings and David Carr on the resurrection of FloraBank, the native seed information and web tool resource, and an update from Steve Benham of the Auckland Botanic Gardens, describing the Threatened Native Plant Garden, an exciting initiative where threatened plants are showcased in replicated versions of their natural habitats, along with other members of the relevant plant community.

Recent issues of Australasian Plant Conservation have been based around a theme, and it is intended to continue with this arrangement. Themes for forthcoming issues include: Conservation of Grasslands and Grassy Ecosystems, Soil Biota in Native Vegetation and Taxonomy and Plant Conservation. Suggestions for themes are welcome, as are articles, especially from parts of the country not well-represented in recent issues, particularly South Australia and Tasmania, and areas of Australasia outside of Australia.

Preparation of Australasian Plant Conservation is a team effort and I would like to draw attention to the contribution of the team of volunteers, acknowledged on the inside cover of each issue, who provide information for the Recent Literature and Resources section and who edit and proof-read articles.