Additive partition of diversity as standard for the selection of protected areas: the natural reserves network of the Siena province (Italy)

Abstract

IntroduzioneL'istituzione di reti di aree protette rappresenta, ad oggi, un mezzo indispensabile per la conservazione della biodiversità (Battisti 2004, Bonn & Gaston 2005. La selezione di nuove aree protette da destina re alla conservazione delle risorse naturali, richiede l'uso di strategie scientificamente valide, soprattutto per fornire una concreta protezione della biodiversi Forest@ 7: 28-43 (2010) , Scoppola A, Nonis D, Gasparini P, Rocchini D, Santi E, Landi S, Maccherini S, Chiarucci A(1) BIOCONNET, Biodiversity and Conservation Network, Dip.to di Scienze Ambientali "G. Sarfatti" Università di Siena, v. Mattioli 4,; (2) Abstract: Additive partition of diversity as standard for the selection of protected areas: the natural reserves network of the Siena province (Italy).Estimating the effects of the spatial components on species diversity represents an important step to establish the conservation "capacity" in a network of protected areas. A clear evaluation on how α, β, and γ diversity are partitioned among and within spatial (and temporal) scales can help us to drive managing decisions and provide methods for monitoring species diversity. Moving from these concepts, a probabilistic sample was applied here: (1) for quantifying plant species diversity at different spatial scales within the network of protected areas existing in the Siena Province (Central Italy); and (2) to evaluate the ef fects on the species diversity of the whole network due to the addition of two new protected areas (Ripa d'Orcia and Bogatto). Focusing on both common species and those defined as "focal" (included in regional, national or continental "red" lists), our results indicated that species richness of the protected areas differed each other independently from the sampling efforts. Diversity partitioning indicated that most of the diversi ty within the network is due to larger-scale β-diversity, i.e., the differences in species composition among re serves. Moreover, total β-diversity was decomposed into two components: β area (due to the differences in area among reserves) and β replacement (due to the compositional differences across protected areas). β area was particularly important for all species, while β replacement was the most important factor for the set of focal spe cies. Noteworthy, the analyzed variation in diversity components due to the inclusion of the two new natu ral reserves into the network (Ripa d'Orcia and Bogatto) resulted in a proportional increase in β Area for the whole network, and, on the other hand, in a reduction for β replacement diversity component. Based on these quantitative results, criteria for the selection and the inclusion of protected areas in existing networks of na tural reserves (such as the Natura 2000 Network) can be achieved.Keywords: Additive partitioning, Conservation biology, Focal species, Plant diversity, Reserve selection, Siena provinceReceived: Sep 14, 2009; Accepted: Feb 11, 2010 Citation: Marcantonio M, Bacaro G, Filibeck G, Scoppola A, Nonis D, Gasparini P, Rocchin...