European mountains have a long history of human presence and exploitation: during the last centuries, agro-pastoral activities determined a lowering of the treeline ecotone and shaped community composition of plants and animals, creating peculiar semi-natural habitats, on which high levels of biodiversity depend on. Currently, two contrasting phenomena are occurring in the rural areas: the abandonment of traditional farming systems in most of the areas and the overexploitation of some remaining pastures. We identified two different approaches to study these events by using insects as bio-indicators. The first one is multi-taxonomic approach, to assess the effects of grazing management on community composition and structure of macro-invertebrates at local scale. The second one is single species approach, the study of population dynamics, habitat preferences and dispersal ability of a target butterfly (included in Annex II of Habitats Directive) to define specific management plans designed for the species conservation. 1) In 2013, the Gran Paradiso National Park started a project in an overgrazed alpine pasture (2000 m a.s.l.), located on a steep stony slope, which was historically grazed but now improperly managed. Indeed, an excessive number of cattle and manure drain on the slope near to dairy barn, threaten ecological integrity of the area. To create an appropriate management plan for biodiversity conservation, a monitoring protocol has been developed to evaluate macro-invertebrates composition at different grazing levels. Four taxa were monitored (Coleoptera Scarabeidae, Coleoptera Carabidae, Orthoptera, Lepidoptera Rhopalocera) by means of semi-quantitative sampling techniques. At a local scale, we evaluated the taxa responses to different grazing pressures and we identified the most suitable indicator (functional) groups for the early detection of grazing impact. 2) Across its European range, the Euphydryas aurinia complex (Annex II of the Habitats Directive) includes a series of distinct populations. At least three taxa occur in Italy, each showing slight morphological differences and distinct eco-ethological features. All of them occupy habitats protected at European level (Habitat 6410, Molinia meadows; Habitat 6210, semi-natural dry grasslands on calcareous substrates; Habitat 4060, Alpine and boreal heaths), threatened by land use changes, which modify both structural and functional connectivity of habitat patches and the quality of the habitat itself. We collected data on adults flight by Mark Release and Recapture method in 15 patches for 2 populations, focusing on specimen density and distribution as a function of landscape and patches’ characteristics (topography and vegetation). We studied E. (a.) glaciegenita population in the mesophilous alpine grasslands (2000-2300 m) and E. (a.) provincialis in the mediterranean dry grasslands (700 m). As shown by results the two populations have different needs. For E. (a.) provincialis a wooded matrix is an unsuitable habitat. Nevertheless, the specimens aggregate in marginal areas of patches, near the edges where thermal conditions are probably more appropriate. The natural reforestation could increase mortality during inter-patch movements. The creation of corridors of suitable habitats between occupied patches and maintaining them by mowing, can definitely help the Mediterranean populations. Since E. (a.) glaciegenita is highly sedentary, changes in grassland management (e.g. increasing grazing regime) could seriously threaten this population, especially during the larval stage. The presence of a heterogeneous environment, also favoured by grazing, can surely support the Alpine populations at landscape, patch and microhabitat levels. The conservation of Alpine and Mediterranean populations may be a key to preserve all the members of the Euphydryas aurinia complex in Italy.
|Data di pubblicazione:||26-set-2016|
|Titolo:||EVALUATION OF AGRO-PASTORAL ACTIVITIES ON INSECT BIODIVERSITY AND CONSERVATION IN NORTHERN ITALY RANGELANDS|
|Settore Scientifico Disciplinare:||BIO/05 - ZOOLOGIA|
|Corso di dottorato:||SCIENZE AMBIENTALI - 09R|
|Citazione:||(2016). EVALUATION OF AGRO-PASTORAL ACTIVITIES ON INSECT BIODIVERSITY AND CONSERVATION IN NORTHERN ITALY RANGELANDS. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2016).|
|Parole Chiave (Inglese):||Euphydryas aurinia; agro-pastoral activities; biodiversity|
|Appare nelle tipologie:||07 - Tesi di dottorato Bicocca post 2009|