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Fire is a major force acting on the structure and dynamics of the Cerrado (Brazilian savanna). Post‐fire conditions can be severe for soil‐dwelling organisms, such as dung beetles, which play essential roles in the Cerrado ecosystem. This study evaluated whether ash residues affect the ecological functions of dung burial and soil bioturbation by the Cerrado‐native beetle Phanaeus palaeno Blanchard (Coleoptera: Scarabaeidae, Phanaeini), and how its sex and weight influence the performance of ecological functions under post‐fire conditions. The beetles were collected from open natural grasslands and pastures in the Cerrado biome, and the functions performed by the individuals were evaluated in the laboratory. The response of beetles was measured by quantifying the amount of buried dung and soil by both females and males in buckets filled with soil, half covered or fully covered with ash, or in buckets without ash. The amount of buried dung or bioturbated soil did not differ among treatments, demonstrating that ash does not influence P. palaeno in performing these functions. Females bioturbated more soil and buried more dung than males, but neither were affected by ash. As dung beetles perform essential ecosystem functions, this information may be helpful in developing novel fire management practices to conserve Cerrado biodiversity. [ABSTRACT FROM AUTHOR]

One of the various ecosystemic services sustained by soil is pollutant degradation mediated by adapted soil bacteria. The pathways of atrazine biodegradation have been elucidated but in situ expression of the genes involved in atrazine degradation has yet to be demonstrated in soil. Expression of the atzA and atzD genes involved in atrazine dechlorination and s-triazine ring cleavage, respectively, was investigated during in situ degradation of atrazine in the soil drilosphere and bulked samples from two agricultural soils that differed in their ability to mineralize atrazine. Interestingly, expression of the atzA gene, although present in both soils, was not detected. Atrazine mineralization was greatest in Epoisses soil, where a larger pool of atzD mRNA was consistently measured 7 days after atrazine treatment, compared with Vezin soil (146 vs. 49 mRNA per 10 6 16S rRNA, respectively). Expression of the atzD gene varied along the degradation time course and was profoundly modified in soil bioturbated by earthworms. The atzD mRNA pool was the highest in the soil drilosphere (casts and burrow-linings) and it was significantly different in burrow-linings compared with bulk soil (e.g. 363 vs. 146 mRNA per 10 6 16S rRNA, 7 days after atrazine treatment in Epoisses soil). Thus, consistent differences in atrazine mineralization were demonstrated between the soil drilosphere and bulk soil. However, the impact of bioturbation on atrazine mineralization depended on soil type. Mineralization was enhanced in casts, compared with bulk soil, from Epoisses soil but in burrow-linings from Vezin soil. This study is the first to report the effects of soil bioturbation by earthworms on s-triazine ring cleavage and its spatial variability in soil. [ABSTRACT FROM AUTHOR]