To allow for long-term metapopulation persistence, a network of habitat fragments must satisfy a certain condition in terms of number, size, and spatial configuration of the fragments. The influence of land-scape structure on the threshold condition can be measured by a quantity called metapopulation capacity, which can be calculated for real fragmented landscapes. Habitat loss and fragmentation reduce the metapop-ulation capacity of a landscape and make it less likely that the threshold condition can be met. If the condi-tion is not met, the metapopulation is expected to go extinct, but it takes some time following habitat loss be-fore the extinction will occur, which generates an extinction debt in a community of species. We show that extinction debt is especially great in a community in which many species are close to their extinction thresh-old following habitat loss because the metapopulation-dynamic time delay is especially long in such species. A corollary is that landscapes that have recently experienced substantial habitat loss and fragmentation are ex-pected to show a transient excess of rare species, which represents a previously overlooked signature of extinc-tion debt. We consider a putative example of extinction debt on forest-inhabiting beetles in Finland. At present, the few remaining natural-like forests are distributed evenly throughout southern Finland, but the number of regionally extinct old-growth forest beetles is much greater in the southwestern coastal areas, where human impact on forests has been lengthy, than in the northeastern inland areas, where intensive for-estry started only after World War II. Ignoring time delays in population and metapopulation dynamics will lead to an underestimate of the number of effectively endangered species.