BiodiversityandConservation 11: 2309–2338, 2002. © 2002 KluwerAcademicPublishers. PrintedintheNetherlands. Extended statistical approaches to modelling spatial pattern in biodiversity in northeast New South Wales. II. Community-level modelling SIMON FERRIER 1,∗ , MICHAEL DRIELSMA 1 , GLENN MANION 1 and GRAHAM WATSON 1,2 1 NewSouthWalesNationalParksandWildlifeService,P.O.Box402,Armidale,NSW2350,Australia; 2 Presentaddress:DepartmentofLandandWaterConservation,UniversityofNewEngland,P.O.Box245, Armidale,NSW2351,Australia; ∗ Authorforcorrespondence(e-mail:simon.ferrier@npws.nsw.gov.au) Received 15 November 2001; accepted in revised form 10 May 2002 Abstract. Regional conservation planning can often make more effective use of sparse biological data by linking these data to remotely mapped environmental variables through statistical modelling. While modelling distributions of individual species is the best known and most widely used approach to such modelling, there are many situations in which more information can be extracted from available data by supplementing, or replacing, species-level modelling with modelling of communities or assemblages. This paper provides an overview of approaches to community-level modelling employed in a series of major land-use planning processes in the northeast New South Wales region of Australia, and evaluates how well communities and assemblages derived using these techniques function as surrogates in regional conserva- tion planning. We also outline three new directions that may enhance the effectiveness of community-level modelling by: (1) more closely integrating modelling with traditional ecological mapping (e.g. vegetation mapping); (2) more tightly linking numerical classification and spatial modelling through application of canonical classification techniques; and (3) enhancing the applicability of modelling to data-poor regions through employment of a new technique for modelling spatial pattern in compositional dissimilarity. Key words: Biodiversity, Communities, Northeast New South Wales, Regional conservation planning, Statistical modelling, Surrogates Introduction Social and economic factors often place severe limits on the total area of land that can be set aside, or otherwise managed, for conservation of biodiversity within any given region. Care must therefore be taken to direct conservation effort to those parts of a region that are assessed as being of highest conservation priority – a process referred to here as ‘regional conservation planning’. The past two decades have seen increas- ing interest in the application of ‘systematic’ approaches to such planning (Margules and Pressey 2000). The aim of these approaches is to design a system of conservation areas that is representative of the diversity encompassed by a region, and to configure these areas to promote long-term persistence of the elements of biodiversity they contain.