Invertebrates are of particular interest on heather moorlands because of their rapid response to small scale habitat changes. Spiders constitute a variable proportion of the diet of heather moorland bird, mammal and reptile species. Furthermore, spiders may be an important indicator of habitat change resulting from management practices, especially those that exert a large- scale spatial impact, e.g. grazing. The component families and species of spider assemblages indicate, through their differing preference for web attachments and web structure, the vegetation density, height and structure (Marc et al., 1999). This effect may be especially pronounced where continued grazing at a particular stocking rate results in characteristic patterns in the vegetation structure. Species and family specific hunting strategies determine prey type and so the presence of some spider species may indicate the presence of a preferred prey species. This study aims to investigate the effect of grazing with sheep alone or in combination with cattle grazing on an upland heather moorland in the north of England.