This paper adopts a social constructionist perspective to examine how the biodiversity 'claim' is constructed and contested at local level. A framework is deployed which is based on Hannigan's ideas that certain factors need to be present for an environmental claim to be legitimised within the international arena. Empirical research into the production and implementation of Oxfordshire's Biodiversity Action Plan and Farm Biodiversity Action Plans in England and Scotland is used as a (...) vehicle to explore the legitimisation of the biodiversity claim at the local scale. The two strands of research highlight the current importance of biodiversity as a focus for environmental planning partnerships and the way in which biodiversity as a 'buzzword' has been adopted by farmers with some reluctance and mainly for financial reasons. There is strong evidence that the scientific basis of the claim is crucial in terms of engendering support, and that the rhetoric employed at the local level is positive rather than a 'rhetoric of loss'. However, the need for further popularisation of the biodiversity issue is identified. Potential future lines of research enquiry are also outlined. (shrink)