Some form of land classification is essential for the conservation of fauna, as a surrogate for detailed survey data and as a framework for the spatial extension of survey results from sampled sites. Recent developments in systematic reserve selection have enabled us to design reserve systems efficiently and defensibly so that they are fully representative of the land classes of a region. Several questions remain, however, about the extent to which a region’s fauna can be adequately protected simply by reserving land classes. Five limitations of land class reservation for the protection of fauna are reviewed: (1) relationships between land classes and variations in the distribution and abundance of species are unclear and difficult to quantify; (2) species are patchily distributed within land classes so reserving a piece of a land class might miss many species; (3) additional attention is needed for species which are threatened or heavily reliant on a region; (4) land classes do not necessarily delineate or recognize areas of critical resources; (5) many species require a combination of habitats not delineated or recognized by land classification. These limitations can be minimized if the problems are addressed through survey and research. Some guidelines for addressing them are suggested.