Biodiversità avicola in alcuni habitat della Riserva Naturale della Palude di Casalbeltrame

The aim of this thesis is the analysis of bird biodiversity within the Nature Reserve of the Casalbeltrame's marsh (Novara district), an area of 640 ha located in an environment altered by intensive rice farming. The analysis of bird biodiversity of the protected area was done using data derived from the ringing activity of MonITRing ISPRA project. The analysis has been focused on the comparison of two habitats of Phragmites australis reed and three habitats present within the Special Nature Reserve. The purpose of the comparisons between the four habitats is to highlight differences in bird biodiversity and provide the protected area management board some data to be used for future planning, especially for wetland reed beds. The research, which began in June 2015 and ended in November 2016, involved the capture of migratory and settled birds through mist-nets arranged in four habitats of the protected area: a woodland/shrub habitat (EUNIS : G1.4 - " Broadleaved swamp woodland not on acid peat"), a glade (EUNIS: E5.42 - " Tall-herb communities of humid meadows") and two areas of Phragmites australis reed (EUNIS: C3.21 - " Common reed (Phragmites) beds¿; EUNIS: D5.11 - " Common reed (Phragmites) beds normally without free-standing water¿); the habitat C3.21 has been destroyed in October 2015 as a result of the cultivation resumption of the rice paddy (previously left in set-aside) where it was placed. To describe the biodiversity of the protected area the alpha diversity indices (species richness, abundance, dominance, Shannon, Simpson, Evenness and Chao1) and the non-Passerine-Passerine ratio were used; to compare the different habitats the Sorensen index was used. Between January 2015 and November 2016, 58 species, for a total of 2935 birds, were captured. The Natural Reserve appears to have a high diversity (Shannon index = 2.95 and Simpson Index = 0.93), but a low equipartition of species (Evenness index = 0.33); the non-Passerine-Passerine ratio (0.26) shows a high ecological value of the site. Comparing bird biodiversity of the four habitats, it was observed that the habitat G1.4 (transect 1) is the most different both for the number of catches and for alpha diversity indices. The habitat D5.11 (transect 3b), while having a smaller number of catches and smaller values of diversity index, has a greater equipartition of species. The habitat C3.21 (transect 3a) has the lowest biodiversity; nevertheless, the nets placed in this environment had allowed the capture of many typical reed beds species that in the other reed habitat have not been captured or have been captured in fewer number. The analysis has highlighted the difference between the two reed habitats (Sorensen Index = 0.44). Considering the importance of reed habitats as a place of rest, shelter and nesting for the species typical of this environment, in an area of intensive rice cultivation which causes strong impacts on migratory birds, it would be necessary to create a new reed bed, comparable with habitat C3.21, within the special nature reserve.