SAEON supports cross-pollination … of research

Dr Marcelo Aizen investigates the green flowers of the Bobbejaanskoen (Whiteheadia bifolia), which was recently found to be pollinated by rodents. In common with South Africa, Argentina has a number of plants that are specially adapted for rodent pollination (Photo by Dr Anton Pauw) Dr Marcelo Aizen (left) and Rhys Hickson, Production Manager for Oak Valley, a fruit producing estate and winery in Elgin. Aizen and Hickson met with researchers from SANBI to discuss ways of improving crop yield through pollinator conservation and management (Photo by Dr Anton Pauw)

In early August Dr Marcelo Aizen visited South Africa as a guest of Dr Anton Pauw of Stellenbosch University on a SAEON funded initiative to foster international research ties in the Fynbos community.

Dr Aizen is based at the Laboratorio Ecotono, Universidad Nacional del Comahue in Argentina where he is a pioneer in studying plant-animal interactions at the community level. He investigates the networks of interactions associated with both pollination and seed dispersal to determine the importance of such mutualism to natural systems and from the perspective of agriculture and human well-being.

While in South Africa, Dr Aizen visited the pollination network study site of the University of Stellenbosch at Traveler’s Rest in the Northern Cedarberg. Dr Pauw described how Dr Aizen’s work had inspired the pollination team at Stellenbosch University to embark on the first study in South Africa of community level pollinator-plant networks a couple of years ago.

This research by Rosanne Stanway for her MSc is the baseline for longer term monitoring of these important processes, which will help us understand impacts of climate change on community processes.

The evolution and ecology of pollination

Dr Pauw highlighted the importance of the South-South collaboration with South America because it is possible to compare and contrast the evolution and ecology of pollination in two biodiverse Gondwanan continents.

In contrast with the northern Hemisphere, where most flowers have non-specific relationships with generalist pollinators, southern hemisphere plant communities include many plants with specialized pollination systems, such as bird pollination, rodent pollination, pollination by oil-collecting bees and by long-proboscid flies.

Because of similar levels of specialization, one might expect these systems to respond similarly to global climate change and other disturbances such as habitat fragmentation. However, whilst these specialist pollination mechanisms are fascinating, Dr Pauw emphasised that it’s the generalist plants and generalist pollinators and plants which are important for maintaining communities because they support many other specialist species that depend on them.

Fynbos Forum

One of the requirements of the SAEON sponsored international researchers is that they present at the Fynbos Forum. This led to an exciting Pollination Symposium at the Fynbos Forum with eleven talks by local pollination researchers. This put pollination as an important consideration for conservation and agriculture in a changing world firmly on the map for delegates.

Dr Aizen’s talk highlighted his research on pollination in agriculture in his presentation: “The global pollination crisis: myth and reality”. He put the global pollination crisis in perspective. The global population of managed honey-bee hives has increased by 45% since 1961, while there has been a much more rapid (>300%) increase in the fraction of agriculture that depends on animal pollination over the same time period. This may be stressing global pollination capacity. Currently 6.1 % of total global crop production is dependent on pollinators. Interestingly, the data Dr Aizen used to produce this analysis is a consequence of the FAO (Food and Agriculture Organisation) keeping long-term records of crop production and honey bee hives over the last half century!

Dr Aizen had a chance to share his experiences in crop pollination on a visit to an Elgin apple farm where SANBI (South African National Biodiversity Institute) staff and students are investigating the pollination of fruit trees. Dr Aizen has investigated the effects of proximity to natural vegetation on crop pollination in Argentina, and has shown that crop production benefits from the proximity of natural vegetation which acts as a source of pollinators. Often these unmanaged pollinators, such as hoverflies and solitary bees which nest in the veld nearby, can be more effective pollinators than managed honeybee hives.

All in all Dr Aizen’s visit sparked new ideas and syntheses, with the potential for an enduring Southern connection.