A decline in pollinating insects in India is resulting in reduced vegetable yields and could limit people’s access to a nutritional diet, a study warns.
Indian researchers said there was a “clear indication” that pollinator abundance was linked to productivity.
They added that the loss of the natural service could have a long-term impact on the farming sector, which accounts for almost a fifth of the nation’s GDP.
Globally, pollination is estimated to be worth £141bn ($224bn) each year.
The findings were presented at a recent British Ecological Society meeting, held at the University of Leeds.
Each year, India produces about 7.5 million tonnes of vegetables. This accounts for about 14% of the global total, making the nation second only to China in the world’s vegetable production league table.
Lack of data
Despite the concern, no study had been done to assess directly the scale of the decline in natural pollinators, explained Parthiba Basu, from the University of Calcutta’s Ecology Research Unit.
“The ideal situation would have been if we were able to compare the overall pollinator abundance over the years, but that kind of data was just not available,” he told BBC News.
Instead, his team compared the yields of pollinator-dependent crops with pollinator-independent crops.
“Data shows that the yields of pollinator-independent crops have continued to increase,” Dr Basu said. “On the other hand, pollinator-dependent crops have levelled off.”
He explained that certain crops did not depend on insects for pollination, including cereals. Instead, the plants used other mechanism – such as relying on the wind to carry the pollen.
However, many vegetables – such as pumpkin, squash, cucumber and gherkin – were reliant on insects, such as bees.
He added that the fall in yield per hectare was against the backdrop of a greater area being turned over to crop production each year.
The exact cause for the decline of pollinators, especially bees, still remains a mystery
Research money has beekeepers buzzing
In an attempt to identify an underlying cause for the pollinator decline, the team is carrying out a series of field experiments, comparing conventional agriculture with “ecological farming”.
Defined as “a farming system that aims to develop an integrated, humane, environmentally and economically sustainable agricultural production system”, ecological farming is almost a hybrid of conventional and organic farming, looking to capitalise on returns from modern farming methods as well as drawing on natural ecological services, such as pollination.
Dr Basu said: “There is an obvious indication that within the ecological farming setting, there is pollinator abundance. This method typically provides the habitats for natural pollinators – this is the way forward.”
He added that if the team’s findings were extrapolated, this would offer a “clear indication” that India was facing a decline in natural pollinators, as ecological farming was only practiced on about 10-20% of the country’s arable land.
Figures show that agriculture accounts for almost one-fifth of the nation’s gross domestic product (GDP), compared with the global average of just 6%. The sector also provides livelihoods for more than half of India’s 1.2 billion population.