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Tiny bees make new buzz for plants

The Royal Tasmanian Botanical Gardens has been researching how it can attract bees to pollinate its collection of threatened plant species. The gardens staff found that many of the plants in the seed orchard were failing to set their seeds properly – hindering efforts to grow stocks to replace those lost to change in their natural habitat – including urban development and agriculture.

The botanic gardens staff are trying to find how to attract some of the state’s 101 species of native bees to pollinate the plants and improve their reproduction. And the lessons being learned in Tasmania will be valuable to farmers, orchardists and horticulturalists in mainland Australia where agriculture could earn millions of dollars from better crops.

Tasmania’s seed repository, SeedSafe, will be able to use the information from the native bee research project to reintroduce and restore the state’s native plant communities. SeedSafe is a collaboration between the Royal Tasmanian Botanical Gardens, the Tasmanian Herbarium, and the Biodiversity Conservation Branch of Tasmania’s Department of Primary Industries, Parks, Water and Environment.

SeedSafe began as part of the Millennium Seed Bank Partnership. Its long-term aim is to hold viable, multi-provenanced collections for the entire Tasmanian flora. It also assists in the reintroduction and restoration of native plant communities.

The public too, including home gardeners, will benefit from SeedSafe’s efforts, as its laboratory germination testing data is published on the Royal Tasmanian Botanical Gardens website. The Germination Database also provides documents explaining the science behind germination and seed dormancy, as well as how to apply germination test techniques at home.

University of Tasmania researcher, honours environmental student Melanie Bottrill has been studying the habits of native bees to find out their preferences and how they might be encouraged to visit the botanic gardens and fertilise agricultural crops. Carrying a net and brightly coloured trays of detergent, Melanie visits sites from Huntingfield to Tunbridge on sunny days when the bees are out and about. She uses the trays to imitate the bees’ favourite flowers and either waits for them to land on the plant or nets them.

Researchers have found that native bees are very effective pollinators compared to European honey bees.

“Basically they’re messy feeders,” she said.

“They end up with pollen everywhere on their underside and hind legs and consequently, they transfer a lot of it to other plants, whereas the honey bees and bumble bees carry a neat little amount that is not as effective for pollination purposes.”

So far Melanie has found about 60 native bee species and worked out that the magnificent gardens do not appear to have enough nesting sites, and there may be too much human disturbance.

“Perhaps the most unusual finding is that native bees strongly prefer blue, yellow or white flowers, rather than the bright reds and oranges,” she said.

Her supervisor, Dr Peter McQuillan, believes there is growing evidence farms in Tasmania’s Midlands will need to find ways to protect and encourage native bees.

“Native bees are attracted to the nectar and pollen on some weeds like dandelions, and remnant native shrubs like prickly box and banksia are also important nectar sources – farmers will need to keep some of those plants in their area to make sure the bees are about

and local councils will need to consider cutting back on roadside spraying.”

Melanie’s bee research is showing that some native bees only go to certain plants and that weather conditions also affect which type of bee will operate.

“The major threat to our native bees is habitat loss and competition from other bees, along with climate change, pesticides, herbicides and monocultures,” she said.

“The message here is that we need to look after our native bees – they can do a job that no other bee can.”