Mauro Paschetta

Grazing history influences biodiversity: a case study on ground-dwelling arachnids (Arachnida: Araneae, Opiliones) in the Natural Park of Alpi Marittime (NW Italy)

Alpine pastures are typical examples of “high nature value farmlands”, representing important habitats harbouring unique biological communities. Disturbance induced by overgrazing influences significantly ecosystem processes, in which invertebrates play a major role. To develop new models of sustainable management of pastures, more knowledge is needed of the animal communities, essential to the ecological functioning of pasture ecosystems. The apparent poor ecological state of several pastures in the Natural Regional Park of Alpi Marittime (NW-Italy) lead us to evaluate the influence of grazing history on biodiversity, using spider and harvestmen assemblages as key groups. Four different pastoral types characterized by four different grazing histories were identified using the Daget-Poissonet method. Spiders and harvestmen were collected by means of pitfall traps. Arachnid assemblages were characterized in terms of composition, abundance, species richness, richness of endemic species and taxonomic relatedness. Generalized linear mixed models (GLMM) were used to test differences among assemblages occurring in each pastoral type. Furthermore, we tested differences in terms of plant communities (species richness and percentage of zoogenic species). Specificity and fidelity of every spider and harvestmen species within pastoral types were explored by the IndVal (Indicator Value) procedure. Fifty-eight species of spiders and seven species of harvestmen were collected (2,304 individuals). Pastoral types related to intensive grazing were characterized by the dominance of diurnal wanderer spiders (namely Lycosidae) while, conversely, nocturnal wanderers (mainly Gnaphosidae) were more abundant in extensive pastoral types. Results show that both species richness and spider abundance were higher in abandoned areas of extensive grazing, while endemic assemblages were richer in extensive grazed areas, which also hosted the most diverse plant community. Furthermore, most of the indicator species of spiders of this type were endemic, characterized by more demanding ecological requirements.

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.

Annotated checklist of the spiders (Arachnida, Araneae) of the Site of Community Importance and Special Area of Conservation “Alpi Marittime” (NW Italy)

ABSTRACT We present an annotated checklist of the spiders (Arachnida Cuvier, 1812; Araneae Clerck, 1757) of the Site of Community Importance and Special Area of Conservation IT1160056 “Alpi Marittime” (NW Italy). The checklist is based on literature records and unpublished material collected from 2007 to 2013 within the first European All Taxa Biodiversity Inventory coordinated by the European Distributed Institute of Taxonomy (EDIT). The examination of the literature provided a list of 113 species recorded for the study area between 1890 and 2013, scattered in 35 publications. The new data provided here raise the total number of species known for the study area to 295, grouped in 147 genera and 31 families. We recorded a remarkable percentage (9%) of endemic species, including rare endemic elements poorly known in literature, such as Vesubia jugorum (Simon, 1881); Troglohyphantes konradi Brignoli, 1975; Nesticus morisii Brignoli, 1975 and Turinyphia clairi (Simon, 1884). For each species we report detailed information about sampling localities, previous citations for the study area (if any), distribution and preferred habitat. 38 species are new records for the regional fauna and four species are recorded for the first time in Italy.

Differentiation among cave populations of the Eukoenenia spelaea species-complex (Arachnida: Palpigradi) in the southwestern Alps

Current knowledge of the taxonomy and distribution of European cave palpigrades largely rests upon incidental records. Samples seldom comprise more than one or two specimens, and many regions have only been unevenly explored, if at all. The present study is the first to investigate morphological variability within, and differentiation between, subterranean palpigrade populations in a small, geographically coherent area. It is based on relatively abundant material from six localities in the SW Alps (Piedmont, Italy) and two non-Italian comparative localities. Discrete and continuous characters reveal, on the one hand, a close grouping within the Eukoenenia spelaea species-complex, and, on the other hand, a remarkable short-range endemism. The occurrence of five distinct morphologies in a SW Alpine area of just 2000 square kilometres or so indicates that subterranean biodiversity parallels the rich above-ground biodiversity there. The Cottian Alps in the North harbour E. roscia Christian sp. n., E. lanai Christian sp. n. and the widespread E. spelaea. Two caves in the Maritime and Ligurian Alps are populated by E. bonadonai, which was originally described from the Provence Alps, while the Bossea cave in the Ligurian Alps remains the only known locality for E. strinatii. We evaluate the traditionally employed morphological characters and those recently proposed for use in Eukoenenia systematics. Further, we provide data on the formerly undescribed females of E. strinatii and E. bonadonai, and provide comprehensive pictorial information on the SW Alpine cave palpigrades to set new benchmarks for the taxonomy of the E. spelaea species-complex.

Regional catalogue of the spiders (Arachnida, Araneae) of Aosta Valley (NW Italy)

ABSTRACT We provide the regional catalogue of the spider species of Aosta Valley (NW Italy, Graian and Pennine Alps) based on literature records and original material collected from 2011 to 2013 in the frame of a collaboration project between the University of Torino and the Regional Museum of Natural Sciences of Aosta Valley. The revision of 1162 literature records scattered in 37 papers published between 1878 and 2015 provided a list of 382 species potentially occurring in this region. On the base of taxonomical and faunistic arguments discussed in the text, we here revise the literature and exclude 74 species from the list, of which seven of unlikely occurrence and 67 in need of verification. The original data here presented raise the total number of species occurring in this region to 384, grouped in 182 genera and 36 families. For each species reported in the catalogue, we provide new collection data, previous literature records, the known distribution and the habitat in which they occurred. Compared with other northern Italian regions and considering its extent, Aosta Valley presents a moderately high number of species, hosting 26% of the species recorded in Italy. In terms of species richness, linyphiids dominate with 99 species (26%), followed by gnaphosids (50 species, 13%), lycosids (45 species, 11%) and salticids (30 species, 7%). Wetlands host cumulatively the highest number of species, followed by shrublands, broadleaved forests and riparian habitats. Regarding chorotypes, most of the species have Palearctic distribution, followed by European and Holarctic species. Alpine endemic species represents 5% of the total.