Aim Changing conditions across spatial gradients are primary determinants of biotic regions, local habitats, and distributional edges. We investigate how a climatic gradient and edaphic mosaic interact as multi-scale drivers of spatial patterns in scarabaeine dung beetles. The patterns are tested for congruency with ecoregion and floral boundaries over the same gradient, as responses to physical factors often differ among higher taxa.Location Southern Africa and the Nama Karoo-Kalahari ecotone, Northern Cape, South Africa.Methods Data consisted of the climatic distributions of 104 species and their abundances at 223 sites in two ecoregions/floral biomes, four bioregions, and 13 vegetation units. Factor analyses determined the biogeographical composition of the species, and regional-to local-scale patterns in species abundance structure. Hierarchical analysis of oblique factors determined the proportional contribution of spatial variance to patterns. One-way anova was used to test for significant separation of patterns along factor axes. Stepwise multiple regression was used to determine correlations of five physical attributes with species richness, ShannonWiener diversity, and factor loadings for the study sites.Results Four biogeographical influences overlap in the study region, although rank contribution declines from south-west arid through north-east savanna to widespread and south-east highland taxa. Species abundance structure comprises five subregional patterns, two centred to the north-east (Kalahari, Isolated Kalahari Dune) dominated by Kalahari influence, and three to the south-west (Nama Karoo subdivisions: Bushmanland, 'Upper', 'Stony Prieska') dominated by south-west arid influence. Kalahari deep sands are characterized especially by a warmer, moister climate, whereas the Nama Karoo mosaic of deep or stony soils is characterized especially by north-west aridity (Bushmanland), south-east cooler temperatures ('Upper'), or excessively stony soils ('Stony Prieska'). Four of the subregional patterns each comprised three localized patterns related primarily to relative stoniness, edge effects from geographical position, or incidence of rainfall. Species richness and diversity declined with decreasing rainfall and increasing stoniness.Main conclusions Climatic and edaphic factors are important multi-scale determinants of spatial patterns in dung beetle assemblage structure, with edaphic factors becoming more important at local spatial scales. The patterns are roughly congruent with the Kalahari Savanna-Nama Karoo ecotone at the floral biome or ecoregion scale, but show limited coincidence with finer-scale floral classification.

1. In many Coleoptera, iridescent colouration is generated by exoskeleton ultra-structure, within which multilayer interference reflects only certain wavelengths. Published work indicates that the colour polymorphism shown by some iridescent beetles is under genetic control. However, the present study suggests environmental involvement in the polymorphic southern African dung beetle, Gymnopleurus humanus Macleay.2. At 24 study sites across a 1000-km latitudinal temperature gradient, population samples of G. humanus were dominated by blue individuals in the cooler south, by cupreous individuals in the warmer north, and by locally co-occurring blue, green and cupreous individuals in intermediate situations.3. Using digital reflectance spectrophotometry, we measured wavelength intensity values across the visible spectrum (400 -800 nm) and used the 70 measured specimens to estimate maximum reflectance from a further 3912 beetles. Differences in mean reflectance values between 24 populations were strongly correlated with average annual temperatures at study sites.4. Much stronger correlations between mean reflectance values and average temperatures of the cool dry season months suggest that the cross-climatic patterns may be related to interaction between breeding seasonality and development under different cooler temperatures.5. Published evidence suggests that inherent physical properties of cholesteric liquid crystals and their responses to different thermal conditions could, potentially, generate the different exocuticle ultra-structure responsible for different reflected colour wavelengths. Furthermore, colour polymorphism could be advantageous across a gradient from cooler to warmer climate as a result of the different thermal properties of different colours.6. Given the correlation with temperature, it is predicted that the prevailing reflected colour balance in southern populations would shift in response to global climatic change.

We questioned the capability of post-mining rehabilitation and successional changes in coastal vegetation to achieve restoration of dune forest, dung beetle assemblages in the Maputaland Centre of Endemism, South Africa.A repeat 2010 study of structural turnover between dung beetle assemblages across a 33 year successional sere of rehabilitating vegetation and old-growth forest (>73 years) produced comparable results to an earlier study across the 23 year chronosequence of 2000. Despite overlap, three structural patterns along the 33 year chronosequence were associated with specific stages of vegetation succession and their characteristic microclimates as in 2000.Although species biased to unshaded habitat dominated the earliest succession, there was rapid re-establishment of dominance by shade-associated forest species. In concert with progression from unshaded, post-mining vegetation to strongly shaded, early successional, Acacia shrub-woodland, there was an initial increase in similarity of the dung beetle fauna (species-poor, low abundance) to that in strongly-shaded forest (also species-poor, low abundance).However, in concert with decreasing shade cover in late successional woodland, the dung beetle fauna became species-rich with high abundance so that the early successional trajectory of increasing similarity to forest fauna either levelled off to a plateau (species in 2000; abundance in 2010) or declined (species in 2010, abundance in 2000). It remains to be seen if gaps forming in the oldest Acacia woodland permit forest tree saplings of the exposed understorey to recreate a forest canopy that would be tracked by dung beetles to re-establish a typically speciespoor, deep shade, forest assemblage with low abundance.

Tswalu Kalahari Reserve is a private game reserve covering 1,020 km 2 in the Northern Cape, South Africa. It has been created from a number of reclaimed farms and restocked with large indigenous mammals. Two surveys were conducted to inventory the dung beetle fauna (Coleoptera: Scarabaeidae: Scarabaeinae) and determine their spatial patterns and food type associations. The spatial survey used pig dungÐ baited pitfall traps to examine dung beetle distribution across three main landscape types (plains, dunes, hills) comprising six principal vegetation communities. The food study examined their relative associations with carrion and four different dung types within a single vegetation community. A total of 70 species was recorded. Because the food association study was spatially restricted and conducted under drought conditions, abundance and species richness (47 species) were much lower than in the spatial study (64 species), which was conducted after substantial rainfall. Principal spatial differences in species abundance structure of assemblages were between the sandy southwest plains and dunes; the sandy northern dune Þelds and plains; and the rocky hills. Forty species analyzed in the food association study showed clear distributional biases to carrion or the dung of elephant (monogastric herbivore), pig (omnivore), cattle and sheep (ruminant herbivores), or pig and cattle. The results (1) show how dung beetle assemblage structure is locally diversiÞed across the heterogeneous landscape of the reserve and (2) indicate how the different dung types dropped by a diverse assemblage of indigenous mammals may variously favor different species of dung beetles.KEY WORDS assemblage structure, dung, Kalahari, landscape, Tswalu Dung beetle distribution patterns across spatial gradients are a response to various interacting factors. These include topography and climate (Kirk and

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