Even if the establishment of nature reserves is to date a reality and the increase of protected areas is going to grow year after year, monitoring programs aiming to assess the effectiveness of the established protected areas for biodiversity conservation are still needed. That is the case for the Natura 2000 network in Europe, for which monitoring methods and programs are not yet well-established. A probabilistic sampling procedure is proposed and tested for quantifying and monitoring plant species diversity within a local network of protected areas, namely the Natura 2000 network in the Siena Province, Italy. On the basis of a sampling strategy of one 100 m 2 plot randomly located in each 1 km × 1 km cell, four Sites of Community Importance (SCIs) were investigated in 2005. The gradients in species composition at the plot scale were largely related to elevation and forest cover. The species richness values of the four SCIs were compared by means of sample-based rarefaction curves. Then, additive partitioning of species richness was applied to determine the most important spatial components in determining the total species richness of the network. Compositional differences among the plots within each SCI were the most responsible of the total species richness. These methodologies can be adopted for assessing plant species richness within a large region or within a reserve network and, if combined with additive partitioning, they can be used as a set of large scale indicators of species diversity.
Allan, J.D. 1975. Components of diversity. Oecologia 18: 359–367.
Allan J.D. , 'Components of diversity ' (1975 ) 18 Oecologia : 359 -367 .
Baffetta, F., G. Bacaro, L. Fattorini, D. Rocchini and A. Chiarucci. 2007. Multi-stage cluster sampling for estimating average species richness at different spatial grains. Community Ecol . 8: 119–127.
Chiarucci A. , 'Multi-stage cluster sampling for estimating average species richness at different spatial grains ' (2007 ) 8 Community Ecol : 119 -127 .
Bock, M., G. Rossner, M. Wissen, K. Remm, T. Langanke, S. Lang, H. Klug, T. Blaschke and B. Vrscaj. 2005. Spatial indicators for nature conservation from European to local scale. Ecol. Indic. 5: 322–338.
Vrscaj B. , 'Spatial indicators for nature conservation from European to local scale ' (2005 ) 5 Ecol. Indic. : 322 -338 .
Chiarucci, A. 2007. To sample or not to sample? That is the question ... for the vegetation scientist. Folia Geobot. 42: 209–216.
Chiarucci A. , 'To sample or not to sample? That is the question ... for the vegetation scientist ' (2007 ) 42 Folia Geobot. : 209 -216 .
Chiarucci, A, G. Bacaro, D. Rocchini and L. Fattorini. 2008. Discovering and rediscovering the sample-based rarefaction formula in ecological literature. Community Ecol. 9: 121–123.
Fattorini L. , 'Discovering and rediscovering the sample-based rarefaction formula in ecological literature ' (2008 ) 9 Community Ecol. : 121 -123 .
Chiarucci, A. and I. Bonini. 2005. Quantitative floristics as a tool for the assessment of plant diversity in Tuscan forests. Forest Ecol. Manage. 212: 160–170.
Bonini I. , 'Quantitative floristics as a tool for the assessment of plant diversity in Tuscan forests ' (2005 ) 212 Forest Ecol. Manage. : 160 -170 .
Chiarucci, A., V. De Dominicis and J. B. Wilson. 2001. Structure and floristic diversity in permanent monitoring plots in forest ecosystems of Tuscany. Forest Ecol. Manage. 141: 201–210.
Wilson J. B. , 'Structure and floristic diversity in permanent monitoring plots in forest ecosystems of Tuscany ' (2001 ) 141 Forest Ecol. Manage. : 201 -210 .
Chiarucci A., N.J. Enright, G.L.W. Perry, B.P. Miller and B.B. Lamont. 2003. Performance of nonparametric species richness estimators in a high diversity plant community. Diver. Distrib . 9: 283–295.
Lamont B.B. , 'Performance of nonparametric species richness estimators in a high diversity plant community ' (2003 ) 9 Diver. Distrib. : 283 -295 .
Chytrý, M. and Z. Otýpková. 2003. Plot sizes used for phytosociological sampling of European vegetation. J. Veg. Sci. 14: 563–570.
Otýpková Z. , 'Plot sizes used for phytosociological sampling of European vegetation ' (2003 ) 14 J. Veg. Sci. : 563 -570 .
Clarke, K.R. 1993. Non-parametric multivariate analyses of changes in community structure. Aust. J. Ecol. 18: 117–143.
Clarke K.R. , 'Non-parametric multivariate analyses of changes in community structure ' (1993 ) 18 Aust. J. Ecol. : 117 -143 .
Colwell, R.K. and J.A. Coddington. 1994. Estimating terrestrial biodiversity through extrapolation. Phil. Trans. R. Soc. B 345: 101–118.
Coddington J.A. , 'Estimating terrestrial biodiversity through extrapolation ' (1994 ) 345 Phil. Trans. R. Soc. B : 101 -118 .
Condit, R., S.P. Hubbell, J.V. Lafrankie, R. Sukumar, R. Manokaran, R.B. Foster and P.S. Ashton. 1996. Species-area and species-individual relationships for tropical trees: a comparison of three 50-ha plots. J. Ecol. 84: 549–562.
Ashton P.S. , 'Species-area and species-individual relationships for tropical trees: a comparison of three 50-ha plots ' (1996 ) 84 J. Ecol. : 549 -562 .
Crist, T.O. and J.A. Veech. 2006. Additive partitioning of rarefaction curves and species-area relationships: unifying alpha-, beta- and gamma-diversity with sample size and habitat area. Ecol. Lett. 9: 923–932.
Veech J.A. , 'Additive partitioning of rarefaction curves and species-area relationships: unifying alpha-, beta- and gamma-diversity with sample size and habitat area ' (2006 ) 9 Ecol. Lett. : 923 -932 .
Crist, T.O., J.A. Veech, J.C. Gering and K.S. Summerville. 2003. Partitioning species diversity across landscapes and regions: a hierarchical analysis of α, β, and γ diversity. Am. Nat. 162: 734–743.
Summerville K.S. , 'Partitioning species diversity across landscapes and regions: a hierarchical analysis of α, β, and γ diversity ' (2003 ) 162 Am. Nat. : 734 -743 .
D’Alessandro, L. and L. Fattorini. 2002. Resampling estimators of species richness from presence-absence data: why they don’t work. Metron 61: 5–19.
Fattorini L. , 'Resampling estimators of species richness from presence-absence data: why they don’t work ' (2002 ) 61 Metron : 5 -19 .
Dungan, J.L., J.N. Perry, M.R.T. Dale, P. Legendre, S. Citron-Pousty, M.-J. Fortin, A. Jakomulska, M. Miriti and M.S. Rosemberg. 2002. A balanced view of scale in spatial statistical analysis. Ecography 25: 626–640.
Rosemberg M.S. , 'A balanced view of scale in spatial statistical analysis ' (2002 ) 25 Ecography : 626 -640 .
Fattorini, L., 2007. Statistical inference on accumulation curves for inventorying forest diversity:Adesign-based critical look. Plant Biosyst. 141: 231–242.
Fattorini L. , 'Statistical inference on accumulation curves for inventorying forest diversity:Adesign-based critical look ' (2007 ) 141 Plant Biosyst. : 231 -242 .
Fattorini, L. and G. Tabacchi. 2004. Inventario Nazionale delle Foreste e dei Serbatoi Forestali di Carbonio: il Disegno di Campionamento, MiPAF — Direzione Generale per le Risorse Forestali Montane e Idriche, Corpo Forestale dello Stato, CRAISAFA, Trento.
Tabacchi G. , '', in Inventario Nazionale delle Foreste e dei Serbatoi Forestali di Carbonio: il Disegno di Campionamento , (2004 ) -.
Ferretti, M. and A. Chiarucci. 2003. Design concepts adopted in long-term forest monitoring programs in Europe—problems for the future? Sci. Tot. Environ. 310: 171–178.
Chiarucci A. , 'Design concepts adopted in long-term forest monitoring programs in Europe—problems for the future? ' (2003 ) 310 Sci. Tot. Environ. : 171 -178 .
Gering, J.C., T.O. Crist and J.A. Veech. 2003. Additive partitioning of species diversity across multiple spatial scales: implications for regional conservation of biodiversity. Cons. Biol. 17: 488–499.
Veech J.A. , 'Additive partitioning of species diversity across multiple spatial scales: implications for regional conservation of biodiversity ' (2003 ) 17 Cons. Biol. : 488 -499 .
Gotelli, N.J. and R.K. Colwell. 2001. Quantifying biodiversity: procedures and pitfalls in the measurement and comparison of species richness. Ecol. Lett. 4: 379–391.
Colwell R.K. , 'Quantifying biodiversity: procedures and pitfalls in the measurement and comparison of species richness ' (2001 ) 4 Ecol. Lett. : 379 -391 .
Hui, C. 2008. On species-area and species accumulation curves: A comment on Chong and Stohlgren’s index. Ecol. Indic. 8: 327–329.
Hui C. , 'On species-area and species accumulation curves: A comment on Chong and Stohlgren’s index ' (2008 ) 8 Ecol. Indic. : 327 -329 .
Kobayashi, S. 1974. The species-area relation I. A model for discrete sampling. Res. Popul. Ecol. 15: 223–237.
Kobayashi S. , 'The species-area relation I. A model for discrete sampling ' (1974 ) 15 Res. Popul. Ecol. : 223 -237 .
Koellner, T., A.M. Hersperger and T. Wohlgemuth. 2004. Rarefaction method for assessing plant species diversity on a regional scale. Ecography 27: 532–544.
Wohlgemuth T. , 'Rarefaction method for assessing plant species diversity on a regional scale ' (2004 ) 27 Ecography : 532 -544 .
Lande, R. 1996. Statistics and partitioning of species diversity, and similarity among multiple communities. Oikos 76: 5–13.
Lande R. , 'Statistics and partitioning of species diversity, and similarity among multiple communities ' (1996 ) 76 Oikos : 5 -13 .
Legg, C.J. and L. Nagy. 2006. Why most conservation monitoring is, but need not be, a waste of time. J. Environ. Manage. 78: 194–199.
Nagy L. , 'Why most conservation monitoring is, but need not be, a waste of time ' (2006 ) 78 J. Environ. Manage : 194 -199 .
McCollin, D., L. Moore and T. Sparks. 2000. The flora of a cultural landscape: environmental determinants of change using archival sources. Biol. Conserv. 92: 249–263.
Sparks T. , 'The flora of a cultural landscape: environmental determinants of change using archival sources ' (2000 ) 92 Biol. Conserv. : 249 -263 .
Melo, A.S. 2004. A critique of the use of jackknife and related onparametric techniques to estimate species richness. Community Ecol. 5: 149–157.
Melo A.S. , 'A critique of the use of jackknife and related onparametric techniques to estimate species richness ' (2004 ) 5 Community Ecol. : 149 -157 .
Nagendra, H. and M. Gadgil. 1999. Biodiversity assessment at multiple scales: Linking remotely sensed data with field information. PNAS 96: 9154–9158.
Gadgil M. , 'Biodiversity assessment at multiple scales: Linking remotely sensed data with field information ' (1999 ) 96 PNAS : 9154 -9158 .
Nekola, J.C. and P.S. White. 1999. The distance decay of similarity in biogeography and ecology. J. Biogeogr. 26: 867–878.
White P.S. , 'The distance decay of similarity in biogeography and ecology ' (1999 ) 26 J. Biogeogr. : 867 -878 .
Palmer, M.W. 1995. How should one count species. Nat. Area J. 15: 124–135.
Palmer M.W. , 'How should one count species ' (1995 ) 15 Nat. Area J. : 124 -135 .
Palmer, M.W., P.G. Earls, B.W. Hoagland, P.S. White and T. Wohlgemuth. 2002. Quantitative tools for perfecting species lists. Environmetrics 13: 121–137.
Wohlgemuth T. , 'Quantitative tools for perfecting species lists ' (2002 ) 13 Environmetrics : 121 -137 .
Palmer, M.W. and P.S. White. 1994. Scale dependence and the species-area relationship. Am. Nat. 144: 717–740.
White P.S. , 'Scale dependence and the species-area relationship ' (1994 ) 144 Am. Nat. : 717 -740 .
Plattner, M., S. Birrer and D. Weber. 2004. Data quality in monitoring plant species richness in Switzerland. Community Ecol. 5: 135–143.
Weber D. , 'Data quality in monitoring plant species richness in Switzerland ' (2004 ) 5 Community Ecol. : 135 -143 .
Podani, J. 1994. Multivariate Data Analysis in Ecology and Systematics . A methodological guide to the Syntax 5.0 package. SPB Publishing, The Hague, The Netherlands.
Podani J. , '', in Multivariate Data Analysis in Ecology and Systematics , (1994 ) -.
Reid, W.V. 1992. How many species will there be? In: T. C. Whitmore and J. A. Sayer (eds.) Tropical Deforestation and Species Extinction . Chapman and Hall, London, pp. 55–73.
Reid W.V. , '', in Tropical Deforestation and Species Extinction , (1992 ) -.
Robinson, G.R., M.E. Yurlina and S.N. Handel. 1994. A century of change in the Staten island flora: ecological correlates of species losses and invasions. Bull. Torrey Bot. Club 121: 119–129.
Handel S.N. , 'A century of change in the Staten island flora: ecological correlates of species losses and invasions ' (1994 ) 121 Bull. Torrey Bot. Club : 119 -129 .
Rodrigues, A.S.L., S.J. Andelman, M.I. Bakarr, L. Boitani, T.M. Brooks, R.M. Cowling, L.D.C. Fishpool, G.A.B. da Fonseca, K.J. Gaston, M. Hoffmann, J.S. Long, P.A. Marquet, J.D. Pilgrim, R.L. Pressey, J. Schipper, W. Sechrest, S.N. Stuart, L.G. Underhill, R.W. Waller, M.E.J. Watts and X. Yan. 2004. Effectiveness of the global protected area network in representing species diversity. Nature 428: 640–643.
Yan X. , 'Effectiveness of the global protected area network in representing species diversity ' (2004 ) 428 Nature : 640 -643 .
Sanders, H.L. 1968. Marine benthic diversity: a comparative study. Am. Nat. 102: 243–282.
Sanders H.L. , 'Marine benthic diversity: a comparative study ' (1968 ) 102 Am. Nat. : 243 -282 .
Stohlgren, T.J. 2007. Measuring Plant Diversity: Lesson from the Field . Oxford University Press, Oxford.
Stohlgren T.J. , '', in Measuring Plant Diversity: Lesson from the Field , (2007 ) -.
Veech, J.A. and T.O. Crist. 2007a. Habitat and climate heterogeneity maintain beta-diversity of birds among landscapes within ecoregions. Global Ecol. Biogeogr. 16: 650–656.
Crist T.O. , 'Habitat and climate heterogeneity maintain beta-diversity of birds among landscapes within ecoregions ' (2007 ) 16 Global Ecol. Biogeogr. : 650 -656 .
Veech J. A and T. O. Crist. 2007b. PARTITION: software for hierarchical additive partitioning of species diversity, version 2.0.
Veech, J.A., K.S. Summerville, T.O. Crist and J.C. Gering. 2002. The additive partitioning of species diversity: recent revival of an old idea. Oikos 99: 3–9.
Gering J.C. , 'The additive partitioning of species diversity: recent revival of an old idea ' (2002 ) 99 Oikos : 3 -9 .
Wiens, J.A. 1989. Spatial scaling in ecology. Funct. Ecol. 3: 385–397.
Wiens J.A. , 'Spatial scaling in ecology ' (1989 ) 3 Funct. Ecol. : 385 -397 .
Wilson, J.B. and A. Chiarucci. 2000. Do plant communities exist? Evidence from scaling-up local species-area relations to the regional level. J. Veg. Sci. 11: 773–775.
Chiarucci A. , 'Do plant communities exist? Evidence from scaling-up local species-area relations to the regional level ' (2000 ) 11 J. Veg. Sci. : 773 -775 .
Yoccoz, N.G., J.D. Nichols and T. Boulinier. 2001. Monitoring of biological diversity in space and time. Trends Ecol. Evol. 16: 446–453.
Boulinier T. , 'Monitoring of biological diversity in space and time ' (2001 ) 16 Trends Ecol. Evol. : 446 -453 .