Biodiversity loss from deforestation may be partly offset by the expansion of secondary forests and plantation forestry in the tropics. However, our current knowledge of the value of these habitats for biodiversity conservation is limited to very few taxa, and many studies are severely confounded by methodological shortcomings. We examined the conservation value of tropical primary, secondary, and plantation forests for 15 taxonomic groups using a robust and replicated sample design that minimized edge effects. Different taxa varied markedly in their response to patterns of land use in terms of species richness and the percentage of species restricted to primary forest (varying from 5% to 57%), yet almost all between-forest comparisons showed marked differences in community structure and composition. Cross-taxon congruence in response patterns was very weak when evaluated using abundance or species richness data, but much stronger when using metrics based upon community similarity. Our results show that, whereas the biodiversity indicator group concept may hold some validity for several taxa that are frequently sampled (such as birds and fruit-feeding butterflies), it fails for those exhibiting highly idiosyncratic responses to tropical land-use change (including highly vagile species groups such as bats and orchid bees), highlighting the problems associated with quantifying the biodiversity value of anthropogenic habitats. Finally, although we show that areas of native regeneration and exotic tree plantations can provide complementary conservation services, we also provide clear empirical evidence demonstrating the irreplaceable value of primary forests.

Summary: Secondary and plantation forests are becoming increasingly widespread in the tropics. A recent meta‐analysis on the impacts of land‐use change on tropical forest dung beetles concluded that regenerating forests can be effective in helping to offset species loss following deforestation. However, our understanding of the extent to which these results can be generalized to new locations remains very poor. We attempted to overcome many of the design limitations that characterize previous studies by collecting spatially independent dung beetle samples from primary, secondary andEucalyptusplantation forests in north‐east Brazilian Amazonia across a large quasi‐experimental landscape that minimized confounding edge and fragmentation effects. We recorded 9203 dung beetles, comprising 85 species. Species richness was significantly higher in primary forest and the majority of species were more abundant there than elsewhere, whereas secondary and plantation sites harboured an impoverished subset of primary forest species. Our data illustrate the low value of tropical secondary and plantation forests for dung beetles in our study area, and our conclusions are more pessimistic than those of earlier studies. Because of differences in the order of species rank‐abundance and rank‐biomass patterns, re‐coding community data from abundance to biomass significantly altered the analytical weight of individual species in determining community patterns. Larger bodied beetles were more prone to local extinctions and abundance declines and this effect was consistent both within and between genera. Synthesis and applications. Our study demonstrates that secondary and plantation forests in a large neotropical landscape host exceptionally impoverished dung beetle communities. Furthermore, the depletion of beetle abundance combined with a reduction in average body mass in converted forests is likely to have detrimental consequences for the maintenance of dung beetle‐mediated ecosystem services in these habitats. Differences in biogeographical and landscape context, and the influence of common limitations in sampling design, may explain why many other studies have painted a more optimistic picture of the conservation value of anthropogenic habitats. In the absence of further evidence we caution strongly against the claim that forest regeneration schemes on degraded land can effectively offset the loss of species following deforestation, and urge that conservation strategies prioritize the protection of remaining areas of primary forest.

A primary goal of community ecologists is to understand the processes underlying the spatiotemporal patterns of species distribution. Understanding the dispersal process is of great interest in ecology because it is related to several mechanisms driving community structure. We investigated the mobility of dung beetles using mark-release-recapture technique, and tested the usefulness of the current recommendation for interaction distance between baited pitfall traps in the Brazilian Atlantic Forest. We found differences in mean movement rate between Scarabaeinae species, and between species with different sets of ecological traits. Large-diurnal-tunneler species showed greater mobility than did both large-nocturnal tunneler and roller species. Our results suggest that, based on the analyses of the whole community or the species with the highest number of recaptured individuals, the minimum distance of 50 m between pairs of baited pitfall traps proposed roughly 10 years ago is inadequate. Dung beetle species with different sets of ecological traits may differ in their dispersal ability, so we suggest a new minimum distance of 100 m between pairs of traps to minimize interference between baited pitfall traps for sampling copronecrophagous Scarabaeinae dung beetles.