Monday, March 25, 2013

Decline of bees forces China's apple farmers to pollinate by hand

The decline of wild bees in China threatens more than just its apple and pear harvests, says pollination expert Dave Goulson.

In the last 50 years, the global human population has nearly doubled, while the average calories consumed per person has increased by about 30%.

To cope with the ever growing demand for food, more land has been brought into agricultural production, mainly by clearing forests, and farming has become much more intensive. Fertilisers, pesticides, and development of new plant varieties have allowed farmers to increase the average yield of food per hectare to increase by 130% in the same period.

It is obvious that this pattern cannot go on for ever; we will run out of forests to clear, and we cannot squeeze ever more food from the same area of land. There are cracks beginning to show; highly intensive farming may not be sustainable in the long term.

Globally, about 75 billion tons of soil is lost every year, washed away or blown out to sea after ploughing. Three hundred and twenty million hectares of land have been affected by a build up of salt due to irrigation practices. Roughly 40% of all agricultural land is now degraded in one way or another.

The role of bees and pollinators

Farming and human health depend upon the ecosystem services provided by wild organisms; worms, woodlice, millipedes and a host of other creatures which help with soil formation, forests to produce oxygen, prevent soil erosion and regulate water flow, birds to eat insect pests, flies and beetles to break down animal dung, bees and other pollinators to pollinate crops.

Modern farming threatens to eradicate these organism, and so undermine itself.

Pollination provides one of the clearest examples of how our disregard for the health of the environment threatens our own survival. About 75% of all crop species require pollination by animals of some sort, often by bees, but sometimes by flies, butterflies, birds or even bats.

Crop pollination by insects has been estimated to be worth $14.6 billion to the economy of the USA and £440 million a year to the UK. Some pollination is done by domesticated honeybees, but the bulk of pollination of most crops is done by wild insects, including many species of wild bee such as bumblebees.

In the UK, for example, recent studies suggest that about one-third of pollination is delivered by honeybees, the rest being carried out by a range of wild insects. These animals need undisturbed places to nest, and flowers to feed on when the crops are not flowering.

However, bee diversity has declined markedly in Europe, with many species disappearing from much of their former range, and some species going extinct. The UK alone has lost three species of native bumblebee, and six more are listed as endangered. Four bumblebee species have gone extinct from the whole of Europe, and there is good evidence for similar declines in North America and China.

Pollinating animals fly in to our fields to pollinate crops from surrounding wild areas, but if there are no wild areas, or if the crops are doused in insecticides, then pollination will suffer and yields will decline. More