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Australasian Plant Conservation

Originally published in Australasian Plant Conservation 15(4), March - May 2007

From the Editor: introducing 'What lies beneath?'

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

This issue focuses on the theme of the recent ANPC National Forum on the topic of 'What lies beneath? The role of soil biota in the health and rehabilitation of native vegetation.'

The Forum concentrated on the soil biota traditionally classified as plants (the blue-green algae, fungi, lichens, mosses, liverworts and hornworts). These share usually small to microscopic size and are often referred to as 'non-vascular plants', 'lower plants' or 'cryptogams'. In fact they belong to a number of the kingdoms of living things: blue-green algae are bacteria (cyanobacteria), fungi comprise a separate kingdom (which also includes lichens), and the bryophytes (mosses, liverworts and hornworts) are plants. This taxonomic diversity is indicative of their varied and vital roles in ecosystems, such as decomposition of organic matter, partnerships with plants through mycorrhizas, and formation of biotic soil crusts.

Among many very interesting pieces of information in Forum presentations, David Eldridge pointed out that effective rainfall for rangeland shrubs is increased by run-off from the biotic soil crust that occurs in the spaces between the shrubs. A report on the Forum appears in this issue, along with abstracts of papers presented, and there are also several papers in this issue which are based on Forum presentations. For other articles relevant to the topic see also previous issues of Australasian Plant Conservation on the themes of 'The forgotten flora remembered', APC 14(1) for June-August 2005, and 'Conserving symbioses', APC 15(2) for September-November 2006.

In a thought-provoking paper not presented at the Forum, but very much on the theme, Andrew Claridge argues for 'Linking the above-ground to the below-ground' and makes a case for 'why we should be restoring processes as well as species in our revegetation efforts'. One of the processes that Claridge highlights is the relationship between plants and fungi through mycorrhizas (literally 'fungus-roots'). Neale Bougher surveys the diversity and roles of a specific group of these fungi, the ectomycorrhizal fungi, that are common in woodlands and forests across Australia. Karl Vernes discusses another of the processes highlighted by Claridge, the interactions between mycophagous (fungus-feeding) mammals and ectomycorrhizal truffle fungi. He makes the point that there are many mycophagous mammals, and considers what might occur when the mammal community that disperses truffle spores is depauperate or missing.

It is important not to focus only on plants, but to consider the full range of interactions among organisms in native vegetation, and several presentations at the Forum dealt with interactions with animals, both vertebrates and invertebrates. Several are covered in the printed abstracts, and in addition Mark Bourne and co-authors describe experiments assessing the beneficial effects of soil and litter invertebrates on plant growth, in revegetation where Acacia is grown alongside Eucalyptus.

The Forum served to raise the profile of soil biota and disseminate information about their important roles, but also to encourage interactions among the people carrying out research on the organisms and interested in applying knowledge to on-ground practice. Two discussion sessions on the Wednesday of the Forum dealt with the conservation of cryptogams and the prospects for 'adding soil biota to the rehab recipe'. The main points from these discussions are summarised below.

It is quite clear from the presentations to the Forum that the hidden soil biota cannot be ignored in revegetation and rehabilitation. Some significant challenges remain, including how to increase the knowledge base on these often overlooked organisms, and how to apply the knowledge to on-ground practice.

One aspect that became apparent when listening to the various talks during the Forum on soil biota is that relatively intact bushland, with its hundreds (perhaps thousands) of species of bacteria, invertebrates, fungi, lichens, liverworts and mosses is a treasure to be greatly valued. It is easy to overlook these organisms because they are usually small and cryptic, but they play such important roles, and provide great resilience to bushland.

It would be very interesting to see an estimate of the cost of fully restoring a hectare of native bush from a cleared site. It is quite feasible to successfully replant the dominant trees, but to bring back the full complement of species (including all the fungi) could well run into hundreds of thousands of dollars or more and take several lifetimes!

Following the soil biota articles, Russell Mawson describes a recent translocation of the endangered greenhood orchid Pterostylis cucullata. It is very useful to document this kind of activity, a point also made by Zoe Smith in her Forum presentation. Future issues of Australasian Plant Conservation are planned to encourage more reporting of trials (to learn from successes, and also failures) and to encourage community groups to document their efforts in plant conservation, such as through translocation, rehabilitation and revegetation.

The final article is a sobering report on the uncertainty about the future of several of the Australian Cooperative Research Centres, including the CRC for Australian Weed Management. The Weeds CRC has many significant achievements and initiatives in both the environmental and agricultural sectors and it is to be hoped that a way can be found, such as through a National Weed Centre, for its vital work to continue.