Pollination is under threat worldwide, UC study

Pollination is under threat worldwide and a University of Canterbury (UC) study has found a whole new way in which bees can be affected by climate change.

UC professor Jason Tylianakis said his recent study found that plant species will go extinct from losing their birds and bees more quickly than expected.

``Three quarters of the world’s food crops require pollination by pollinators (bees and birds etc) but our research shows this natural service is under threat. Our research showed that climate change and widespread fertiliser use can disrupt the relationship between plants and pollinators, for example by making flower nectar less nutritious for bumblebees, causing them to die more quickly.

``The nutritional quality of nectar can reduce the survival of bees as we first discovered earlier this year. Climate can affect how plants grow and the size and shape of their flowers and this can make flowers less attractive to pollinators.

``Bee species will decline if they can’t survive climate changes, and we know from previous work that bee diversity is important for pollination success.’’

The biggest problem for pollination in New Zealand was the introduction of the Varroa mite, which is moving its way down the country. This affected honeybees, which were a species introduced to New Zealand and would potentially make crops more dependent on bumblebees and wild native bees (and some flies) for pollination.

Agricultural practices worldwide negatively affect native pollinators because they tended to nest in woodlands or natural areas, rather than in commercial hives.

``So we may have already harmed the species we need most. UC masters student Simon Litchwark is currently studying how the reduction of honeybees will affect crop pollination.

``Animal pollination is needed for three quarters of the world’s food crops, and we can already see examples worldwide where pollinator abundance and diversity are declining, and this is affecting crop productivity.

``The species most likely to go extinct are those that depend strongly on each other. For an extreme example, if an orchid is only pollinated by one bee species, and that bee only pollinates that one orchid, they’ll both be highly likely to go extinct.

``This is worrying from a conservation standpoint, because these rare specialist species will be lost quicker than you’d expect at random. For agriculture it’s not such an issue, because most NZ crops are pollinated by many different species.’’

Plant and bee species that depend most strongly on each other will be the most likely to suffer from environmental changes, and this accelerates the extinction of both plant and pollinator species, he said.

Although the news for natural and crop ecosystems is bad, his study project highlighted the benefits of international exchanges and collaborations between researchers. The project arose through a visit to UC by a PhD student from Argentina.