Assessing the Biodiversity Value of Stands and Patches in a Landscape Context

Landscapes are often shaped by decisions taken at the scale of individual stands or patches. In this chapter we make the following points. Biodiversity assessments at the scale of individual stands or patches must be undertaken in the landscape context. Landscape measures only inform land-use decisions when they can be interpreted at the scale in which land-use decisions are taken. In a management context, landscape units must be surrogates for multiple species and ecological processes, although no single unit will suffice as a surrogate for biodiversity generally, so risk-spreading strategies such as defining landscapes at multiple scales should be employed. Vegetation cover, pattern and patch content are measures often used to assess the biodiversity value of landscapes and impacts of change in landscapes. Vegetation cover and pattern are often assessed as though vegetation or habitat is binary (present or absent) and therefore the patches are uniformly good and the matrix uniformly hostile. Patch content is rarely assessed in a landscape context.We discuss how patch content can be interpolated at landscape scales and how this information can inform the way landscapes are defined and how cover and pattern are assessed.We suggest that spatial data on habitat attributes will enable us to view and assess landscapes as continua of habitats rather than discrete patches in a hostile matrix. From this discussion, six landscape principles are derived.