A new investigation conducted by Curtin revealed that the Marri trees are fundamental for the survival of more than 80 species of native bees in the southwest region of Western Australia, which is one of the biologically richest yet most threatened biodiversity hotspots in the world.
The lead author, Kit Prendergast, an adjunct researcher at Curtin’s School of Molecular and Life Sciences, said that the study identified the Marri (Corymbia calophylla), native to the Southwest and listed as a Near Threatened species in 2019, as a crucial food supplier for native bees and a defender of the region’s ecosystem.
“The findings that these trees support at least 81 different species of foraging bees in the Southwest highlight their extraordinary role in the survival of native bee populations, particularly toward the end of summer when most other plants have ceased to flower,” says Prendergast.
“As Southwest WA native bees are abundant and incredibly diverse, and many depend heavily on native plants such as the Marri for feeding,” he adds.
“The Marri trees provide vital nectar and pollen, especially at a time when few other plants are in bloom. For many bee species, the Marri is often the only food source available at this time of year,” he reveals.
“Moreover, this tree not only provides food sources for native bees but also nesting resources, with species observed nesting in small holes and among the roots, and its copious iconic red sap is used by the Megachilidae bees to seal their nests,” he adds.
Prendergast asserts that the research provides new evidence supporting the idea that certain species, such as the Marri tree, serve as “keystone” or “anchor” species, playing a particularly crucial role in maintaining biodiversity.
“The Marri is a vital resource for native bees, acting as a lifeline during the critical periods when other plants dry up,” says Prendergast.
“The results point to an urgent need to protect Marri trees from threats such as logging, mining, fires, diseases, agriculture and urban and industrial development, because without this tree, many native bee species would have difficulty surviving,” he adds.
The study also revealed that Marri trees are often the primary, or even the only, plant species visited by these bees throughout the year, making them indispensable to the local ecosystem, which underscores the importance of conserving this species, not only for the bees but for the health of the landscape in general.
The research was funded by the Forrest Research Foundation, by Zanthorrea Nursery and by the Department of Biodiversity, Conservation and Attractions.
The complete study, titled “Corymbia calophylla (Marri): A Major Resource for Native Bees in the Southwest Western Australian Biodiversity Hotspot” will be published in the journal Pacific Conservation Biology (doi.org/10.1071/PC24054) and once published will be online here.
