To recognise International Pollinator Week last week, the journal Nature published a paper by a collaborative of authors from across the planet. One of the authors, Dr Ro Hill from CSIRO Land and Water, in Cairns, provided input from the Australian situation and perspective.
The most well-known pollinator is the bee – either Apis minifera (European honey bee) or, to a lesser extent, native bees of which there are around 1,500 species. However, there are hundreds of other insects, bats and birds essential to ensure certain food crops are pollinated.
According to Dr Hill, pollination services are in decline for many reasons.
“The information collected from around the world indicates the loss of habitat is the number one cause of the decline in numbers of pollinators”, she said.
“The removal of forests, understoreys, deaths of riparian zones, land being cleared for monocultures and housing, and the widespread use of herbicides is resulting in hundreds of species of pollinators declining every year”.
“The continuous sowing of annual crops as opposed to having a mix of perennial and annual plants does not provide any habitat at all for pollinators, either for that crop (if needed) or for other plants which need pollinating”.
Dr Hill described a situation in South America when the tree canopy was removed from above coffee plantations. What hadn’t been understood was the role migratory birds played in pollinating the trees but, this was realised when crops failed. Once the taller trees finally grew and provided roosting for the birds, the coffee trees could finally reach full production again.
The Daintree rain forest is a location where significant quantities of high-value durian fruit could now be grown. Traditionally, durian has been grown in south east Asia but, due to the destruction of habitats for bats, the main pollinating agent for durian, this sector is no longer viable.
The efforts to conserve the Daintree rain forest have been worthwhile for many reasons, and now include the potential for a new tropical fruit industry.
Dr Hill explained the situation in Europe where giant agri-chemical company, Bayer, has take the European Union to court to contest the EU’s banning of insecticides known as neonictonoids.
Anecdotal evidence of the deaths of bees from this product were fairly widespread but inconclusive so the EU banned them using the Precautionary Principle as their reasoning. This Principle was invoked as there was doubt or lack of evidence proving the insecticides were not harming the bees.
In Australia, there is huge reliance on bees for pollinating around 75 per cent of all food crops grown. According to Dr Saul Cunningham, a pollination researcher with the CSIRO and Visiting Fellow with The Fenner School at the Australian National University, Australia is the only country not to have varroa mite in it, at the moment.
“Varroa is a parasite which ultimately kills bees and every other major agricultural producing country has lost most of their bee populations to it. In Australia, we are fortunate to have a possible Plan B, our native bees but, unless there is widespread planting of habitat for them, they, too, will fade out”, Dr Cunningham explained.
"Our research shows that native vegetation grown along the edge of paddocks can increase the number of native insects that visit crops, ultimately leading to more production."
The native blue-banded bee can increase tomato yields by 20-24% over the current method of hand-pollination. This bee is widespread and common on mainland Australia and has the potential to pollinate not just tomatoes, but eggplant and sweet peppers as well.
"Native bees might not be the only answer to reduce our exposure to loss of pollinators, but they are part of the solution. Diversifying your options for pollination could be the way of the future”.
Dr Hill suggested that strips of perennial native vegetation in cropping paddocks wouldn’t interfere with the sowing and harvesting and would provide permanent habitats for a host of species.
“It is amazing how far tiny insects will travel but, in huge tracts of monoculture cereals there is very little, if any, habitat left for them. Imagine if cereal farmers included specific biodiversity hot-spots in their paddocks which is as easy as planting trees, understorey plants and perennials, and allowing the natural processes to take place. In a relatively short time, there would be pockets of active pollinators and healthier eco-systems”, she concluded.
More information and how you can become involved is available at https://research.csiro.au/gihh/