Background: why conserve pollinators?
What is pollination?
Pollination occurs when pollen is moved within flowers or carried from flower to flower by pollinating animals or by the wind. The transfer of pollen between flowers of the same species leads to fertilization, and successful seed and fruit production for plants. Pollination ensures that the plant will produce full-bodied fruit and viable seeds. For crop producers, this means good yields of high quality produce, for consumers, it means the availability of a range of fruit and vegetables at an affordable price, and for the wider environment, it means a healthy ecosystem.
Who are the pollinators in Ireland?
Although a range of animals visit flowers to collect food (nectar and/or pollen) the most important pollinators in Ireland are insects; particularly bees and hoverflies.
Globally, bees are the most important pollinator because they visit flowers to collect food for their larvae, as well as feeding exclusively on flowers as adults. Hence the entire life-cycle of bees is dependent on interactions with flowering plants. Of the 100 crops that provide 90% of the world’s food supply, 71 are pollinated by bees.
While adult hoverflies feed mainly on nectar and pollen, the larvae of many species are voracious predators of aphids and other pests. As a result, hoverflies are important as they contribute to both pollination and pest control.
In Ireland, there are 97 different species of bee, including the familiar honeybee (1 species) and bumblebee (20 species). The remaining species are solitary, meaning they do not form colonies. Only the honeybee produces commercially extractable honey. There are 180 species of hoverfly in Ireland.
The honeybee has long been domesticated by humans and managed for honey production and/or crop pollination. In the last 20 years, bumblebees have been available commercially for use in covered (glasshouse) crops. Recent collapses in honeybees due to a range of factors have caused widespread concern with regards to crop pollination, particularly in North America. Global honeybee declines have highlighted the risks associated with the reliance on a single pollinating species. Furthermore, recent studies in the UK have shown that the honeybee is not as important as a crop pollinator as previously believed, and it makes up only a small fraction of insect visits to flowers in Irish agricultural systems.
The importance of wild, non-managed bees as pollinators of not only crops, but also wild plants is becoming more and more apparent. Studies have shown that a diversity of pollinator types is important for maximizing pollination.
“To provide stable pollination services for our crops, crop wild relatives (potential future crops) and other wild plants, we need to maintain both wild and managed pollinators in the landscape.”
Why does pollination matter to us?
Reduction in the diversity/abundance of pollinators and/or pollinator loss can reduce crop yield. The annual value of pollinators for human food crops has been estimated at €153 billion world-wide, £603 million in the UK and €53 million in Ireland. Regional estimates of the value of pollinators to individual crops have also been made, with values of up to $41million for blueberry pollination in Oregon (USA), £36.7 million for apples in the UK and €3.9 million for oilseed rape in Ireland. The cost of replacing pollination services provided by animals by artificial means (e.g. human hand pollination or pollen dusting) can be substantially higher. Furthermore, animal-pollination can improve shelf-life of soft fruits, further increasing their value. Wild pollinators can act as insurance against decline in managed pollinators, driven by pest/disease outbreaks. Pollination also improves the nutritional value of some crops and animal-pollinated crops are crucial for providing vitamins, anti-oxidants and other essential nutrients to the human diet. Pollination also has a non-market value as pollinators contribute directly and indirectly to human well-being in other ways. For example, people derive pleasure from bees and pollinator-dependent habitats such as flower-rich meadows. The value of this is harder to determine, but is demonstrated by public support for organisations such as the Bumblebee Conservation Trust and Limerick’s Buzzing.