Cairns Botanic Gardens fungi report 2022 update BARRY MUIR
The role of botanic gardens as repositories for fungal conservation is now well recognised. Botanic gardens in Kew (England), New York and Denver (USA), Melbourne (Australia), Komarov (near St Petersburg, Russia), Paris (France), Kunming (China), Xalapa (Mexico), and Cuba now house both preserved collections of fungi and living communities of fungi. Of course, many parks and gardens support fungal populations by default, even if not a recognised part of their management plan. The Cairns Botanic Garden Precinct (the Precinct), for example, is known to support at least 224 species of large fungi and probably thousands of species of microscopic fungi, although fungal protection and preservation is not formally part of its mandate. Thus, the role of the Precinct in fungal conservation is of inestimable value. Over the last four years an inventory has been made of macrofungi in the Precinct. Of the 224 species recorded so far, only 22 (9.8%) are known disease-causing species. Considering that thousands of visitors from all over the world have passed through the Precinct and that visitors carry fungal spores on their skin, clothes and shoes, it is a testament of how well the Precinct is managed, as healthy plants are much less prone to disease. It is known that at least 90% or more of all green plants on the planet depend on symbiotic fungi (called mycorrhizae) for their existence. Which species of fungi are involved is still being researched and so some recyclers, and perhaps even some disease-causing species, may eventually be found to have a mycorrhizal role for all or part of their lifecycle. At least 50 (over 22%) of all large fungi recorded in the Precinct are primarily mycorrhizal, and therefore play a vital role in maintenance of plant health. A single species of plant may have several mycorrhizal associates and a single mycorrhizal fungus may cooperate with several plant species. The remaining fungi in the Precinct are predominantly recyclers. Fungi, together with bacteria, are the primary recyclers of all dead animal, fungus, plant and other organic material on the planet. Those species that break down fallen palm fronds, twigs, branches, logs and old tree stumps are most common in the rainforest and other “natural” areas.
The Flecker Garden has an area of about 29ha and has produced many fungi, some shared with other areas and some unique to Flecker Garden. Flecker Garden has experienced a long history of introduction of plants from all over the world, either directly or via Australian suppliers, many of whom obtained the plants from overseas. Some of these plants were introduced to the Garden as potted specimens as early as the 1890s, and, because the plants were healthy, carried a suite of their essential mycorrhizal fungi with them. Some of these mycorrhizae are now established in Flecker Garden. Searches for the suspect species outside Flecker Garden have failed to find any, suggesting that they may require their specific host plant and have not, and will not, spread further. All the parasitic species found so far occur more widely in Australia, and it is probably safe to say that there is no evidence that Flecker Garden is the epicentre of any kind of spread of exotic diseases, or even of exotic decomposer-recyclers. It can be expected that the Precinct rainforest and adjacent areas, totalling about 358ha, will contain a plethora of fungal species, many of which are probably undescribed. The rainforest remnant near the boardwalk is a vital conservation area, firstly because about 126ha of it has no formal access and so has been protected from human disturbance for some time, and because it is the only remaining plot of intact coastal rainforest left anywhere in the vicinity of Cairns. What remains elsewhere is either narrow/linear along drainage lines or road verges, on private land under threat of clearing, or has been heavily invaded by exotic plants and feral pigs. The interior of the preserved rainforest in the Precinct has not been surveyed for fungi. However, the 46 macrofungi that have been recorded only from rainforest are from near the ‘boardwalk rainforest’, or adjacent to the Tanks Art Centre. In the Precinct, there are about 26 species of fungi which appear to be new to science, although they could be species from overseas, or Far North Queensland variants of southern species. This suggests that the Precinct has a significant role in conservation of some fungal species whether they be Australian native species or introduced.
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