What about the nematodes? Taxonomic partialities in the scope of UK biodiversity conservation Jamie Lorimer School of Geography, Oxford University Centre for the Environment, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK, jamie.lorimer@ouce.ox.ac.uk Since their inception in 1980 the concept of biodiversity and the practical techniques of biodiversity conservation have experienced a meteoric rise in popularity as a mode of understanding and governing the environment. This paper draws on concepts from science studies and posthumanist geography to outline a new approach to biodiversity. In contrast to the objective, disembodied and panoptic definition offered in the official documentation, it explores what biodiversity comes to mean in practice in a UK context. It argues that biodiversity must be understood as the discursive and material outcome of a socio-material assemblage of people, practices, technologies and other non-humans. It then applies this understanding to examine the scope of the assemblage that performs UK biodiversity conservation. In so doing it maps a set of taxonomic divisions. Drawing on empirical fieldwork, it examines one particular arena within this assemblage—species surveillance—and identifies the importance of the detectability of a species and taxonomic divisions in resources for accounting for these partialities. In conclusion, it reflects upon the benefits of this new approach for understanding biodiversity and biodiversity conservation. Key words: biodiversity, environmental governance, practice, non-human agency. Introduction Since their inception in 1980 the concept of biodiversity and the practical techniques of biodiversity conservation have experienced a meteoric rise in popularity as a mode of understanding and governing the environment (Hannigan 1995; Jeffries 1997). Concept and practice achieved global recognition at the UN Earth Summit in Rio de Janeiro in 1992 when 155 states signed the Convention on Biological Diversity (CBD). Biodiversity arrived in the UK in 1994 through the drafting and subsequent implementation of the UK Biodi- versity Action Plan (UKBAP) (HMSO 1994) and has become increasingly influential in land use policy and planning (Bishop and Philips 2004; Marren 2002). Numerous definitions of biodiversity exist (see De Long 1996; Sarker 2002) but the most widely accepted is that which emerged from the Earth Summit and has been incorporated Social & Cultural Geography, Vol. 7, No. 4, August 2006 ISSN 1464-9365 print/ISSN 1470-1197 online/06/040539-20 q 2006 Taylor & Francis DOI: 10.1080/14649360600825687