Polllination - a global crisis unfolding?
Pollination is a building block of life but the world faces a potential crisis as habitat destruction, invasive species, disease and pests and potential climate change disruption create monumental changes in the relationships between pollinators and plants.
Landcare Research scientist Dr Linda Newstrom-Lloyd has outlined the problem as part of a project in conjunction with Science Alive! to teach children and the wider community about the role and importance of pollination.
Pollination is the movement of pollen from the male part of one flower to the female part of another flower. Some plants have their pollen carried by the wind but the majority of plants depend on pollen transfer by small insects such as bees, flies, butterflies, moths, beetles and/or larger animals such as birds, lizards and bats. The plant benefits from pollination because the flower is fertilised and makes seeds and fruit. The pollinator benefits because it eats the nectar and pollen rewards and bees bring pollen back to their nests for their offspring. Pollinators are important in three contexts: to maintain biodiversity in conservation and restoration of our native plants; to sustain our economy for agricultural exports; and to provide food security and diversity in agriculture and our home gardens.
‘When you buy from the supermarket one out of every four bits of food that you purchase relies on a pollinator, Dr Newstrom-Lloyd says.
‘Our health depends on pollinators since 70% of crop species need pollinators. So, if we are losing our pollinators, we’re losing our agricultural yields and food diversity. And, if our native plants are also losing pollinators then eventually they could disappear...the issue is as serious as climate change,’ Dr Newstrom-Lloyd warns.
Dr Newstrom-Lloyd says New Zealanders ignore the importance of pollination at their peril.
It is tempting to think that we can rely on managed populations of bumblebees and honeybees in New Zealand because they are generalists visiting many native and exotic flowers and most crops, and they have a longer foraging season and are active for more hours per day than our native bees. But studies have shown that the bumblebee and honeybee are not always the best pollinators for all types of flowers; pollinator diversity keeps all options open. High pollinator diversity also results in improved fruit quality and more seeds, which is vital for the success of native plants in natural ecosystems, and crop plants whether in large monocultures or our home gardens. ‘Depending on a few types of pollinators such as the bumblebee and honeybee is like putting all of our eggs in one basket,’ Dr Newstrom-Lloyd says.
‘If those social bees were wiped out due to parasites or disease and we did not take care to ensure native pollinators persisted, then we would be left with nothing. This is the ultimate biological crisis.’
Climate change could also have a dramatic impact. Changes in plant and animal distributions and potential changes in cues such as temperature for seasonal activity could cause the timing of pollinators’ life cycles to fall out of sync with the onset of flowering. Dr Newstrom-Lloyd says the problem in New Zealand is compounded because we don’t know how bad the problem is since we lack even basic information.
‘We need to know what types of pollinators we have – bees, flies, butterflies and so forth – and establish the importance of the different pollinators for each plant species. And, it can be complicated because we have exotic and native pollinators that visit exotic and native plants. There is a great deal of crossover and therefore we need to know in what way our pollination systems have already been disrupted and what the current status and trends are.’
She is undertaking baseline monitoring, developing a database where all info can be gathered and disseminated, and also developing predictive risk assessment models to understand how much redundancy and resiliency there is in the system. ‘We do not have a good understanding of the degree of specialisation versus generalisation in the New Zealand pollination systems. The critical question is what would happen to the pollinator network if you dropped out a given species of plant or pollinator?’ she says.
As co-chair of the Oceania Pollinator Initiative, Dr Newstrom-Lloyd is prioritising research activities that are included in the Plan of Action for the Global Pollinator Initiatives co-ordinated by the Food and Agriculture Organisation (FAO). These priorities are to assess and monitor the status and trends in loss of pollinators worldwide, identify the specific causes of pollinator decline, estimate the economic cost associated with reduced pollination of crops, determine and promote best practices and technologies for more sustainable agriculture, and identify and encourage the adoption of conservation practices to maintain pollinators or to promote their re-establishment.
Public awareness is crucial to this plan of action and for this reason the Landcare Research Community Pollination project has made the educational potential of the Science Alive! Botanica exhibit a top priority.