Augusto Vigna Taglianti

Hotspots of biodiversity and conservation priorities: a methodological approach

This is a methodological paper aimed at comparing methods to assess regional biodiversity. In more detail we compared the effectiveness of hotspots of species richness, of rarity and complementarity in evaluating local animal diversity. Species distributions were sampled over a 10×10 km UTM grid across the Italian territory. We considered 471 species of zygaenids, butterflies, carabines, amphibians and reptiles. Hotspots were analysed at national and regional levels and considered taxa either all together, or separately. To test the predictive value of complementarity analysis, we initially excluded zygaenids. At national level, of 3218 10×10 km UTM quadrats sampled, 161 (5% of total) had highest species richness. Islands included only 1 hotspot (Sicily). Sixty‐eight species (14.4%) were not represented. They were mainly endemic (65%), insular (73.5%), or rare (25%). Working taxon by taxon, hotspots numbered 433. Only 85 (19.6%) were hotspots contemporaneously for two taxa and only 9 were hotspots for 3 taxa. Missing species were fundamentally insular species. The regional‐level approach generated 467 hotspots. Eleven species were not represented (2.3%). They had marginal distributions, or were insular endemites. Hotspots of rarity numbered 235 and 10 species were not included. Results demonstrated that hotspots are poor predictors of overall biodiversity. The complementarity method identified 67 quadrats. By definition, these quadrats accounted for all species investigated. They failed, however, to predict the occurrence of three zygaenids. As expected, complementarity provided better results than hotspots analysis. Combining the two methods assures that areas having the highest biodiversity are identified, even working with incomplete databases. Regional or rarity hotspots should generally be preferred to hotspots of species richness.

Stand maturity affects positively ground-dwelling arthropods in a protected beech forest

Key messageForest maturity benefits biodiversity by providing positive effects on key arthropod assemblages such as spider and ground beetles, which play a fundamental role in the ecosystem.ContextSustainable forest management is a widely held international goal, and more knowledge is needed on invertebrate assemblages, essential to the ecological functioning of forest ecosystems.AimsWe aim at evaluating the effects of microsite conditions on spider, centipede, and ground beetle assemblages living in an unmanaged protected beech forest within the Natural Park of Alpi Marittime (SW Alps, Italy). In view of our results, we provide insights on the successional pathways of the focal assemblages in relation to future management of the forest, recommended by the local authorities for conservation purposes.MethodsWe placed 50 pitfall traps along four transects crossing the forest and emptied them monthly, from July to October 2011. We characterized the four arthropod assemblages in terms of abundance, species richness, diversity, and biomass and related them to leaf cover, rock cover, wood debris cover, litter depth, number of trees, mean tree size, and light conditions at ground level using generalized linear mixed models (GLMM) and canonical correspondence analysis (CCA).ResultsThirty-one species of spiders (1,212 individuals), 12 of centipedes (262 individuals), and 11 of ground beetles (2,177 individuals) were collected. In all groups, mature-forest species highly dominated the samples. Tree size proved to be one of the most important parameters conditioning the assemblages, in particular spiders and ground beetles. A minor effect of light conditions and ground cover (presence of wood debris) was also detected.ConclusionsIn view of our results, the recent guidelines for the management of the forest seem in accordance with an effective conservation of the forest arthropod assemblages. Interventions aimed at stabilizing and renovating critical areas within the forest go along with a progressive amelioration of the forest arthropod community. With respect to the maintenance of a large degree of arthropod diversity, stand thinning may not be the most effective management, and reaching a more mature stage might be of interest.

Biochemical systematics and phylogeography of the percus strictus subspecies (coleoptera, carabidae), endemic to Sardinia

Abstract Allozymic variation at 14 loci was studied in six Sardinian populations of the carabid beetle Percus strictus. These populations represent the four subspecies of P. strictus recognised on morphological grounds in the island. Clustering and multivariate analyses were able to discriminate different subspecies, supporting the morphological evidence. Genetic distance data and .P‐sta‐tistics analysis indicated a certain degree of isolation among subspecies, but not high enough to propose the splitting of the polytypic F‐strictus into different species. From molecular clock and geological data, it is inferred that the major differentiation events were due to vicariance and took place at the beginning of the Pliocene, in concomitance with sea introgressions that subdivided the island into different blocks roughly corresponding to the present ranges of the different subspecies.

The diet of a coastal population of European bee‐eaters (Merops apiaster) compared to prey availability (Tuscany, central Italy)

Abstract We studied the diet of a coastal population of European bee‐eaters during the 1986 breeding season by pellet analysis and estimates of prey availability. The results showed that the population fed preferentially on Hymenoptera, which were more preyed upon than their availability in both May and July. Beetles were the second prey category, Odonata and Hemiptera being included in the diet mainly in July, when food needs of the chicks forced the adults to include larger prey items in their diet. Diptera were always rejected by bee‐eaters despite their great availability in both months.

Fauna Europaea: Coleoptera 2 (excl. series Elateriformia, Scarabaeiformia, Staphyliniformia and superfamily Curculionoidea)

Abstract Fauna Europaea provides a public web-service with an index of scientific names (including synonyms) of all living European land and freshwater animals, their geographical distribution at country level (up to the Urals, excluding the Caucasus region), and some additional information. The Fauna Europaea project covers about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. This represents a huge effort by more than 400 contributing specialists throughout Europe and is a unique (standard) reference suitable for many users in science, government, industry, nature conservation and education. Coleoptera represent a huge assemblage of holometabolous insects, including as a whole more than 200 recognized families and some 400,000 described species worldwide. Basic information is summarized on their biology, ecology, economic relevance, and estimated number of undescribed species worldwide. Little less than 30,000 species are listed from Europe. The Coleoptera 2 section of the Fauna Europaea database (Archostemata, Myxophaga, Adephaga and Polyphaga excl. the series Elateriformia, Scarabaeiformia, Staphyliniformia and the superfamily Curculionoidea) encompasses 80 families (according to the previously accepted family-level systematic framework) and approximately 13,000 species. Tabulations included a complete list of the families dealt with, the number of species in each, the names of all involved specialists, and, when possible, an estimate of the gaps in terms of total number of species at an European level. A list of some recent useful references is appended. Most families included in the Coleoptera 2 Section have been updated in the most recent release of the Fauna Europaea index, or are ready to be updated as soon as the FaEu data management environment completes its migration from Zoological Museum Amsterdam to Berlin Museum für Naturkunde.

Patterns of beta diversity in riparian ground beetle assemblages (Coleoptera Carabidae): A case study in the River Aniene (Central Italy)

Abstract We investigated riparian ground beetle communities to: (1) identify the main environmental factors determining species composition; (2) determine whether sites with similar ecological characteristics have similar species composition as a result of local selection; and (3) provide some indications for conservation of these insects. For 45 sampling sites in the River Aniene we measured: elevation, river bank morphology, percentage of shaded area, habitat heterogeneity, sediment depth, sediment granulometry and geographic position. We then used Canonical Correspondence Analysis (CCA) to investigate the importance of these variables in structuring beetle communities and cluster analysis (CA) to identify groups of sites with similar species composition. Granulometry and elevation were the most important parameters influencing species composition. Position of assemblages in CCA space was partially similar to their groupings in CA. In particular, silty sediments hosted a homogeneous group of species (with several highly specialized elements), well separated from all other clusters, suggesting that this type of substrate exerts a strong local selection pressure on ground beetle species. Communities characterized by species associated with coarse sediments were typically found in isolated localities. Further isolation of these populations by impoundments would have a serious impact on their persistence.

Use of taxonomic and chorological diversity to highlight the conservation value of insect communities in a Mediterranean coastal area: the carabid beetles (Coleoptera, Carabidae) of Castelporziano (Central Italy)

We used the carabid beetles inhabiting the Castelporziano Presidential Estate reserve (a natural reserve of some 60 ha facing the Tyrrhenian sea) to show how chorotypes (i.e. species distribution types) can be used to characterise insect communities. We compared three forms of diversity: species richness, Clarke and Warwick taxonomic diversity and chorological composition. Chorological composition was modelled using Menhinick, Margalef, Shannon, and Brillouin diversity, Simpson dominance, Pielou evenness and Buzas and Gibson evenness. Variations in carabid species richness, chorological composition (richness, diversity, dominance and evenness) and taxonomic diversity among biotopes followed different patterns thus providing complementary not redundant information. Beach, dunes, high maquis and oak forest were biotopes with low species richness, whereas wet woodlands, mixed forest, wet zones and open areas have high species richness. Low maquis had an intermediate position. This subdivision is substantially confirmed by indices of chorological composition. However, in contrast with large variations in diversity indices, evenness was substantially similar, and relatively high in all biotopes, even those with very small numbers of species. Taxonomic diversity was also similar among biotopes, being however small in oak forests and open areas. When species richness, chorological diversity and taxonomic diversity were used to calculate an index of overall conservation interest, the most important biotopes resulted to be wet zones, wet woodlands, open areas and mixed forest. These results clearly indicate that the carabid communities with high conservation values are those associated with humid environments. This is consistent with the hypothesis that most of the carabids species occurring in the study area are hygrophilous elements, associated with wetlands, which shifted their range southwards during the glacials, and which form a relict component of the carabid fauna of coastal areas.

Assessing patterns of co-occurrence and nestedness of arthropod assemblages in an artificial–natural Mediterranean forest mosaic (Isopoda Oniscidea, Coleoptera Carabidae)

We compared two soil arthropod assemblages (Isopoda Oniscidea and Coleoptera Carabidae) in an artificial–natural Mediterranean forest mosaic. Using data from pitfall traps, we investigated through a co-occurrence analysis whether local ecomosaic supported non-random organized arthropod assemblages, and we compared the results between the two taxa. We evaluated “the effect of reforestation” on forest species of both assemblages using nestedness and indicator value analyses, and wing morphology analysis in the case of the ground beetle assemblage. A significant difference between the assemblages is turned out, probably because woodlouse are more specialized in spatial niche than ground beetles. Overall, there is a clear evidence of randomness in the woodlouse assemblage structure. Moreover, forest woodlouse species and brachypterous ground beetles appear affected by “the effect of reforestation” in the study area.