title: The impact of overgrazing on dung beetle diversity in the Italian Maritime Alps.
abstract: Dung beetles (Coleoptera: Scarabaeidae) are undoubtedly the most typical and ecologically relevant insects of grazed alpine habitats because they provide valuable ecological services such as biological pest control and soil fertilization. Despite the great ecological contribution of  these insects to pasture ecosystem functioning, little is known about their direct or indirect relationships with pastoral activities. The main aim of the study was to assess whether dung beetle diversity was influenced by different intensities of cattle grazing. Dung beetle communities of  two adjacent alpine valleys within the Maritime Alps Natural Park (north-western Italian Alps), representing overgrazed and ungrazed pastures, were studied by pitfall trapping. A hierarchical design (three levels: valleys, transects, and replicates) was established for additive partitioning  of γ-diversity and Indicator Species Analysis. Evenness and Shannon diversity were significantly higher at the ungrazed than at the overgrazed site because abundances were much more evenly distributed at the former than at the latter site (where one species was dominant over all the  others). Dung beetle abundance and species richness of the overgrazed graminaceous pasture vegetation types were in most cases significantly lower than those of the ungrazed nongraminaceous vegetation type. In the additive partitioning of γ -diversity analysis relative to the whole study  area, the randomization procedure indicated that the contribution of β to γ-diversity was significantly different from that expected by chance, suggesting that one or more environmental factors has intervened to change the partition of total diversity in the system considered. The  analysis of the preferences and fidelity of species (Indicator Species Analysis) showed that only one species chose overgrazed pastures; all the others positively selected the ungrazed site, or the only ungrazed pasture vegetation type (Rumicetum alpini Beger) occurring at the overgrazed site.  Results conformed to evidences that overgrazing represents a serious threat to the conservation of alpine dung beetles. To conserve local dung beetle assemblages, especially in protected areas, cattle overgrazing should be avoided. This does not mean, however, that pastoral activities are  incompatible with biodiversity conservation. The contemporaneous presence of wild ungulates and low intensity extensive pastoral activities may be useful to preserve both local dung beetle assemblages and alpine pasture ecosystems.
authors.affiliation: Dipartimento di Biologia Animale e dell'Uomo, Università degli Studi di Torino, Torino, Italy. matteo.negro@unito.it
authors.forename: Matteo
authors.initials: M
authors.lastname: Negro
authors.forename: Antonio
authors.initials: A
authors.lastname: Rolando
authors.forename: Claudia
authors.initials: C
authors.lastname: Palestrini
mesh_terms: D000818:Animals; D044822:Biodiversity; D002417:Cattle; D001517:Coleoptera; D060434:Herbivory; D007558:Italy