Changes in human land use have driven and continue to drive much of the change in biodiversity locally, nationally and globally. The dominant trend is reduced area of habitats with high biodiversity and increased area of habitats with low biodiversity. Apart from lost area and general degradation of habitat quality, the remaining area of species-rich habitats has become increasingly fragmented. By increasing fragmentation we mean that a continuous habitat splits into two or more distinct fragments; that existing fragments become smaller; and that they become increasingly isolated from the rest of the habitat. In all these situations, habitat fragmentation is typically accompanied by further loss of the pooled area of habitat. None the less, it is possible, and appropriate, to ask questions about fragmentation per se, about the influence of the spatial configuration of a given amount of habitat on the abundance, distribution and viability of populations. This is highly relevant for practical conservation, which often deals with choices, such as exactly where habitat should be protected, managed or restored. To answer such questions about the spatial configuration of habitat, we need to employ relevant concepts and methods. In this chapter, we focuson highly fragmented landscapes, in which only a small fraction of the total landscape area belongs to the habitat type or types of interest, and in which the habitat that exists occurs in relatively small and discrete patches. Many insects with specific habitat requirements occur in landscapes that are highly fragmented for natural reasons or because human land use has turned a continuous habitat into a highly fragmented one.
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