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|Authors: ||Casale, Fabio|
|Internal Tutor: ||MARTINOLI, ADRIANO|
|Title: ||Ecology and conservation of red-backed shrike (Lanius collurio) in semi-natural habitats of north-western Italy.|
|Abstract: ||Species conservation largely depends on knowledge of habitat needs of target species. On the other hand, breeding habitat plays an essential role in the life-history of birds. Many bird species are currently threatened by unfavourable environmental changes or by habitat destruction or degradation prompted by human activities, in particular farmland birds. This dramatic and widespread decline has been related to agricultural intensification, especially through loss of ecological heterogeneity. Also land abandonment, which mainly affects marginal areas and is often indirectly caused by intensification, negatively affects several bird species.
The red-backed shrike Lanius collurio (Aves: Laniidae) is a typical passerine species of Euroasiatic low-intensity farmland landscapes and is one of the species most sensitive to agricultural changes.
This species underwent large declines over most of Europe during the last century, disappearing almost completely from large areas, and being consequently listed in the Annex I of the Birds Directive (79/409/EEC). The main reason for the decline is probably linked to the increased intensification and mechanization of traditional agriculture, which led to unfavourable changes of breeding habitats. However, conditions in the African wintering grounds or migratory stop-over areas may also have affected its population status. Recently, some studies have tried to address habitat determinants of species’ occurrence and breeding performance in many areas, but studies in southern Europe are still scarce and most works deal with central or northern Europe.
Lombardy, northern Italy, includes portions of both the Alpine and Apennine chains, which at intermediate elevations host key populations of red-backed shrike. Lowland areas in the region have undergone heavy agricultural intensification (generally heavier than in the rest of Italy), resulting in wide extensions of specialized cultivations, often with a single crop occupying tens or hundreds of hectares (especially Zea mais), without marginal features (as hedges, shrubs or tree patches).
Therefore, conservation of farmland birds in hilly and mountain areas, where changes of agricultural practices have been less dramatic, is a priority for bird conservation in Italy, and especially in Lombardy. At the same time, land abandonment is dramatically reducing open habitats in hilly and mountain portions of the region, thus leading to further unsuitable modification to the breeding habitats of shrikes and other farmland or ecotonal species.
Red-backed shrike is one of the most threatened species in Lombardy and is listed among conservation priority species by the regional government. Although the species seems to have dramatically declined, for example in Varese and Bergamo provinces, few quantitative data are available to compare the current and previous estimates of population size and distribution.
We developed a multi-level conservation strategy for Lanius collurio in Lombardy, starting from a regional-wide assessment of habitat preferences, whose results were translated into conservation priorities over different spatial scales and in a regional Action Plan for the conservation of the species.
After defining habitat associations, we i) described conservation priorities (at landscape scale) over the whole region, by identifying the most important populations of the species, main areas of potential occurrence and main threats and conservation needs in terms of large-scale habitat change, ii) derived territory-level guidelines for management of different habitats occupied by the species.
Management guidelines include a description of the habitat mosaic virtually representing the most suitable option for the species in different environmental contexts (permanent grasslands, pastures, shrublands, heathlands, vineyards) inhabited by L. collurio in Lombardy and best practices favourable for the species. On average, the definition of proportion of habitat variables in an ideal territory of a breeding pair of red – backed shrike in Lombardy includes: 60% of grazed or mowed grasslands; 20% of bushes; 10% of untilled grasslands; 70 meters of hedges; 60 meters of fences.
Furthermore, for each suitable breeding habitat for the species in Lombardy we determined the ideal mosaic of vegetation in one hectare of surface that can hosts a breeding pair of red-backed shrike (e.g. for permanent grasslands: 73% mowed of grazed grassland; 12% untilled grassland; 10% shrubs; 5% hedges).
Finally, an ‘Action Plan for the conservation of Red-Backed Shrike in Lombardy’ was produced, based on a long-term strategy of conservation of the species in Lombardy region. Its adoption by the regional government of Lombardy is currently under way.|
|Subject MIUR : ||BIO/03 BOTANICA AMBIENTALE E APPLICATA|
|Issue Date: ||2010|
|Doctoral course: ||Analisi, Protezione e Gestione delle Biodiversità|
|Academic cycle: ||22|
|Publisher: ||Università degli Studi dell'Insubria|
|Citation: ||Casale, F.Ecology and conservation of red-backed shrike (Lanius collurio) in semi-natural habitats of north-western Italy. (Doctoral Thesis, Università degli Studi dell'Insubria, 2010).|
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