Parametri biogeografici della Biodiversità. Struttura e rapporti del popolamento siculo a Scarabeidi degradatori (Coleoptera, Scarabaeoidea).

In this paper, we studied the relationships between ecobiogeography and historical biogeography, based on Sicily’s population of Scarab dung beetles (Geotrupidae and Scarabaeidae).We based the island’s ecogeographic partition on its floristic districts and subdistricts (Brullo et al., 1995).We applied some techniques of biodiversity analysis to the study of I and II order chorotypes (Bellucci et al., 2007; Zunino, 2005, 2007). Species and groups found correspond to 14 chorotypes of I order and to 22 of II order, differently represented and distributed in the sample. The !, and " diversities were studied with both hierarchical levels of chorology. The obtained results, using different indexes, confirm Sicily’s landscape heterogeneity. # diversity does not refute the proposed phytogeographic island’s partition in districts. The analysis of the districts’ similitude, on the other hand, seems to refute the hierarchically superior partition in subsectors. In fact, all the calculated indexes agree on grouping districts that in the phytogeographic classification belong to different subsectors. Therefore, with the comparative analysis of the I order chorotypes, the synchronic relations of the studied Sicilian faunistic component are discussed. Finally, through the analysis of the II order chorotypes, considered as spaces that are occupied by panbiogeographic tracks, the relationships of the Sicilian Scarab beetles are examined with a historical biogeography standpoint, suggesting hypotheses of primary biogeographic homologies. From the same analysis, it becomes satisfactorily clear that Sicily is included in more than one panbiogeographic node, and that this is evidence of its involvement in allotopic and allochronic biogeographic histories

On the road of dung: hypothetical dispersal routes of dung beetles in the circum–Sicilian volcanic islands

We analysed dung beetle communities on ten volcanic islands located around Sicily (Italy) to identify the most probable dispersal routes in the colonization of these islands. Assuming two scenarios, we analysed the dung beetle communities through the coefficient of dispersal direction DD2. Our results suggest that dispersal fluxes do not strictly follow the ‘stepping stone’ dynamic. Lipari and Vulcano are the likely core source areas for the north–of–Sicily area. In the Sicily Channel, Linosa appears to have been the main target area with three equivalent fluxes from Tunisia, Sicily, and Malta, while the fauna of Pantelleria resulted from their interchange and proximity to Tunisian fauna. In light of the congruence of our results with the known history of human movements and colonization, we propose a likely human contribution to the genesis of the dung beetle fauna of the circum–Sicilian volcanic islands

Cumulative Annual Dung Beetle Diversity in Mediterranean Seasonal Environments

Species diversity assessments should consider the dynamic nature of ecological communities, especially in highly seasonal ecosystems. Here we provide a comprehensive framework for analysing seasonal changes in species composition, richness and diversity in two local dung beetle (Coleoptera: Scarabaeoidea: Aphodiidae, Geotrupidae, and Scarabaeidae) communities from Western Tuscany (Italy), in the Mediterranean ecoregion. We test whether, in this highly seasonal region, cumulative annual diversity is an oversimplification of well differentiated seasonal communities. Data were obtained through repeated standardised samples collected regularly over an entire year. We clearly identify different summer and winter communities at each site based on species composition and abundance. Seasonal richness and diversity values are different from the cumulative annual values, as a consequence of beta diversity between seasons, and some dung beetle species are identified as idiosyncratic of each particular season. Both ecological (niche partitioning) and biogeographical factors are suggested as drivers of these temporal variations. Thus, because local inventories of fauna that include records over long time periods actually reflect situations where coexistence and interactions are unlikely to occur, highly seasonal sites must be viewed as having temporally differentiated communities in order to reach feasible and reliable baselines for local diversity assessments. © 2011 The Ecological Society of Japan

Cumulative annual dung beetle diversity in Mediterranean seasonal environments.

Species diversity assessments should consider the dynamic nature of ecological communities, especially in highly seasonal ecosystems. Here we provide a comprehensive framework for analysing seasonal changes in species composition, richness and diversity in two local dung beetle (Coleoptera: Scarabaeoidea: Aphodiidae, Geotrupidae, and Scarabaeidae) communities from Western Tuscany (Italy), in the Mediterranean ecoregion. We test whether, in this highly seasonal region, cumulative annual diversity is an oversimplification of well differentiated seasonal communities. Data were obtained through repeated standardised samples collected regularly over an entire year. We clearly identify different summer and winter communities at each site based on species composition and abundance. Seasonal richness and diversity values are different from the cumulative annual values, as a consequence of beta diversity between seasons, and some dung beetle species are identified as idiosyncratic of each particular season. Both ecological (niche partitioning) and biogeographical factors are suggested as drivers of these temporal variations. Thus, because local inventories of fauna that include records over long time periods actually reflect situations where coexistence and interactions are unlikely to occur, highly seasonal sites must be viewed as having temporally differentiated communities in order to reach feasible and reliable baselines for local diversity assessments. © 2011 The Ecological Society of Japan