As oil prices sore and the future of world energy is uncertain, there is rising demand for alternatives to fossil fuels. From solar energy to wind to algae fuel and biodigestion, the alternatives are numerous. One alternative that has received substantial media attention is the use of bioenergy which involves the production of energy from crops including maize, sugarcane, elephant grass and oilseed rape which are grown specifically for energy purposes.
However, the debate over bioenergy crops is often heated. Do they compete with food crops and therefore increase prices in an already stretched market? Do bioenergy crops result in the destruction of tropical rainforest to clear new areas for farmland? And are bioenergy crops even carbon neutral to begin with?
One debate that has been investigated by researchers in Trinity as part of the Simbiosys project is whether bioenergy crops can have impacts on biodiversity – the animals and plants that live on and in farmland. Not only are these animals and plants an important part of our heritage, but they are the pollinators of our food crops, the insects that control agricultural pests and the organisms that help provide us with clean water and air. With two-thirds of Irelands land area used for farming, any changes in farming practice are likely to have knock-on impacts on biodiversity.
A study recently published in the Journal of Applied Ecology investigated how growing bioenergy crops impacts the bees and other pollinating insects that pollinate wild flowers, apples, berries, oilseed rape, clover and many other crops here in Ireland (in fact pollinators are required for approximately 1/3 of all the food we eat). It was found that although different types of insect responded differently, there were no decreases of pollinators in bioenergy crop fields in comparison to their conventional farming alternative. And for some pollinator groups such as the small solitary bees, the introduction of small amounts of different crops into agricultural areas may actually be beneficial.
However, bioenergy crops did not provide the stable nesting conditions needed for pollinators; almost all bumblebees chose to nest in the field margins and hedgerows surrounding the fields. Field margins and hedgerows also provided habitat for large numbers of other insects. The study concluded that small amounts of bioenergy production on existing farmland may provide a diversity of habitats for pollinating insects, but that changes in levels of production in the future may have different effects. Hedgerows and field margins should also be maintained during bioenergy production as they are important nesting and forage sites for pollinating insects.
Although bioenergy crops in their current form seem like good news for bees, the future may be less certain. Growing these crops over larger areas rather than in individual fields, or the replacement of forests or meadows rather than existing arable (tilled) land, may have very different effects. With EU targets of 20% energy from renewable sources by 2020, and bioenergy incentives for farmers, we can expect further changes in this developing sector over the next few years.
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stanleyd[at]
Photo credit
Dara Stanley