Assessing the Ecological Impacts of Bioenergy Projects.

One of the major objectives of the current expansion in bioenergy cropping is to reduce global greenhouse gas emissions for environmental benefit. The cultivation of bioenergy and biofuel crops also affects biodiversity more directly, both positively and negatively. Ecological impact assessment methods for bioenergy projects (including changes to policy and land use) should address not simply changes to species abundance at field level, but include larger scale issues, including changes to landscape diversity, potential impacts to primary and secondary habitats and potential impacts on climate change. Such assessments require a correspondingly broad range of scientific methods, including modelling of climate and land use as well as the observation of biodiversity and landscape indicators. It is also possible to adopt evidence-based guidelines for good practice for situations where comprehensive assessments are not available. These might include favouring projects and policies that avoid gene flow to wild relatives of crops in centres of diversity, that do not result in invasion by the crop into other habitats, that enhance field-scale biodiversity, that increase landscape diversity, that do not threaten valued habitats within the local landscape, that promote the sustainable management of biodiverse habitats, that do not increase the risk of loss of primary habitats and that result in a proportionately large reduction in greenhouse gas emissions.