Heritage trees matter too

One of the historic trees under threat from the 20-year old flying-fox camp in the Royal Botanic Gardens

As I announced in a media release a week ago, it is now too late to relocate the flying-foxes from Sydney’s historic Royal Botanic Gardens this year.

Our window of opportunity is May to July – after breeding and before the flying-foxes are carrying their young. And while the State Government has given approval, discussions are continuing with the Commonwealth Government. Even if a decision is made swiftly, it will take several weeks to set up the necessary research and monitoring before starting the noise disturbances.

We expect the flying-foxes to relocate relatively quickly to other Sydney camp sites, probably within two weeks. But we do need to allow for contingencies, such a new camp being established in an unsuitable area and further relocation being needed. Two months would be ideal.

So the flying-foxes stay another year. The camp arrived in the Royal Botanic Gardens 20 years ago, after a 70-year absence from this site. In those two decades we have lost 18 mature trees – about one a year. The camp peaks to about 22,000 animals in summer but drops to about 5000-10,000 in winter.

Good rainfall and excellent tree care have allowed the trust to nurse through many of the most severely affected trees, but as each year passes we stand to lose another of our majestic specimens.

While the approvals quite rightly take into account the welfare of the flying-foxes, they cannot take into account the damage caused to one of the world’s great botanical collections. The Commonwealth are doing their job, considering our application under the terms of the Environment Protection and Biodiversity Conservation Act 1999, but what about the health and long-term viability of our botanic gardens?

Let me make it clear, it’s not the botanic gardens or the flying-foxes. The Trust is confident it can safely relocate flying-foxes: the same techniques were used successfully to move a similar sized camp in Melbourne six years ago and to reduce numbers here in Sydney in the 1990s. If nothing is done, the botanic gardens will be trashed and the flying-foxes will need to move find a new place to camp, as they did twenty years ago when they returned to the botanic gardens.

Mass planting of fast-growing trees as roosting sites isn’t the answer. The tree collection is of immense scientific and heritage importance, and demonstrates the diversity of the world’s flora. We have started collecting seed from the wild to propagate and eventually restore the Palm Grove.

The 192-year old Royal Botanic Gardens is listed on the National Trust Register as a Landscape Conservation Area, and under the NSW Heritage Act as an item of Environmental Heritage. The Conservation Management Plan for the Royal Botanic Gardens identifies the whole site to be of exceptional national, state and local significance.

The Palm Grove, where most of the bats roost, is one of the older and more significant landscapes in the Gardens. The trees date back to the 1820s, and most of the palms to the 1860s. We’ve already lost a magnificent Kauri pine (Agathis moorei) collected by Charles Moore from New Caledonia in 1850. Of most concern at the moment is a Red Cedar collected from Parramatta in 1822 by the first head of the Botanic Gardens, Charles Fraser, and a Flindersia collected on the Oxley Expedition to the Brisbane and Logan Rivers in 1828.

There are 48 species of wild-collected palms, many of them rare in cultivation. Our Pritchardia maideniana were for many decades the only mature specimens of this species thought to exist in the world. Just a few years ago our collections were used to confirm the identity of a possibly natural population rediscovered in Hawaii.

Several new fungal species have been discovered and described from palms in the Palm Grove so these specimens become what we call ‘type localities’ – important scientific reference points. There are also many trees which are difficult to collect or rare in the wild, providing critical specimens for scientific study.

Under our current licences we’ve done all we can to deter the flying-foxes from the most sensitive trees. We’ve tried python poo, toilet crystals, shrimp paste, strobe lights, directed water sprays (when water was more freely available), plastic bags tied to branches, and even the colourful Inflatable Man. Over the next year we may have to net a few of the more important trees. None of these measures offer any long-term solution.

Carefully managed noise disturbance is proven and safe, and the welfare of the flying foxes will be paramount. Relocation is essential if we are to save Australia oldest botanic garden and its precious tree collection.