Standardized sampling methods are essential for comparing species diversity and abundance patterns across different studies and sites. Although dung beetles are widely used as a focal taxon in biodiversity studies, nothing appears to be known about the effective sampling area of dung‐baited traps. Mark‐recapture experiments using Canthon acutus showed that at least 50 m between traps should minimize trap interference, and that wind affects trap detectability. Consequently, we propose a standardized dung beetle sampling design.

A guild of neotropical rain forest dung scarabs, collected by baited pit traps, was composed of 11 genera and 31 species of Scarabaeinae. Relative abundances were highly equitable. Population densities were high and stable through the transition from wet to dry season. Competition for dung was intense and removal and burial rates were rapid. Resource use differed between genera and species in diel flight activity, foraging and dung removal methods, and behavior. Interspecific aggression and dung stealing behaviors were well developed. Reproductive activity was inversely correlated with aggression and parental investment.

Anthropogenic disturbances such as fragmentation are rapidly altering biodiversity, yet a lack of attention to species traits and abundance patterns has made the results of most studies difficult to generalize. We determined traits of extinction-prone species and present a novel strategy for classifying species according to their population-level response to a gradient of disturbance intensity. We examined the effects of forest fragmentation on dung beetle communities in an archipelago of 33 islands recently created by flooding in Venezuela. Species richness, density, and biomass all declined sharply with decreasing island area and increasing island isolation. Species richness was highly nested, indicating that local extinctions occurred nonrandomly. The most sensitive dung beetle species appeared to require at least 85 ha of forest, more than many large vertebrates. Extinction-prone species were either large-bodied, forest specialists, or uncommon. These explanatory variables were unrelated, suggesting at least 3 underlying causes of extirpation. Large species showed high wing loading (body mass/wing area) and a distinct flight strategy that may increase their area requirements. Although forest specificity made most species sensitive to fragmentation, a few persistent habitat generalists dispersed across the matrix. Density functions classified species into 4 response groups on the basis of their change in density with decreasing species richness. Sensitive and persistent species both declined with increasing fragmentation intensity, but persistent species occurred on more islands, which may be due to their higher baseline densities. Compensatory species increased in abundance following the initial loss of sensitive species, but rapidly declined with increasing fragmentation. Supertramp species (widespread habitat generalists) may be poor competitors but strong dispersers; their abundance peaked following the decline of the other 3 groups. Nevertheless, even the least sensitive species were extirpated or rare on the smallest and most isolated islands.

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