Barker, R. J. and Sauer, J. R.: Statistical aspects of point count sampling, in: Monitoring Bird Populations by Point Counts, edited by: Ralph, C. J., Sauer, J. R., and Droege, S., General Technical Report PSW-GTR-149, Pacific Southwest Research Station, Forest Service, US Department of Agriculture, Albany, CA, 125–130, 1995.
Berland, A: Long-term urbanization effects on tree canopy cover along an urban–rural gradient, Urban Ecosys., 15, 721–738, https://doi.org/10.1007/s11252-012-0224-9, 2012.
Blair, R. B: Land use and avian species diversity along an urban gradient, Ecol. Appl., 6, 506–519, 1996.
Blair, R. B.: Birds and butterflies along an urban gradient: surrogate taxa for assessing biodiversity?, Ecol. Appl., 9, 164–170, 1999.
Blair, R. B. and Johnson, E. M.: Suburban habitats and their role for birds in the urban-rural habitat network: Points of local invasion and extinction?, Landsc. Ecol, 23, 1157–1169, 2008.
Blair, R. B. and Launer, A. E.: Butterfly diversity and human land use: species assemblages along an urban gradient, Biol. Conserv., 80, 113–125, 1997.
Blasi, C., Capotorti, G., Celesti-Grapow, L., Ercole, S., Filesi, L., Lattanzi, E., Michetti, L., Paolanti, M., and Tilia, A.: Land use types and vegetation maps of the Rome Municipality 1 : 50,000, Comune di Roma, Roma, 2001.
Bogosian, V., Hellgren, E. C., and Moody, R. W.: Assemblages of Amphibians, Reptiles, and Mammals on an Urban Military Base in Oklahoma, Southw. Natur, 57, 277–284, 2012.
Buckland, S. T., Anderson, D. R., Burnham, K. P., Laake, J. L., Borchers, D. L., and Thomas, L.: Introduction to distance sampling, Oxford University Press, Oxford, 2001.
Burnham, K. P.: Summarizing remarks: Environmental influences, in: Estimating numbers of terrestrial birds, edited by: Ralph, C. J. and Scott, J. M., Stud. Avian Biol., 6, 324–325, 1981.
Cam, E., Nichols, J. D., Sauer, J. R., Hines, J. E., and Flather, C. H.: Relative species richness and community completeness: birds and urbanization in the mid-Atlantic states, Ecol. Appl., 10, 1196–1210, 2000.
Celesti Grapow, L.: Atlante della Flora di Roma (Atlas of the flora of Rome), Argos, Comune di Roma, Roma, 1995.
Chesson, P.: Mechanisms of maintenance of species diversity, Annu. Rev. Ecol. Syst., 31, 343–366, 2000.
Cignini, B. and Zapparoli, M.: Atlante degli uccelli nidificanti a Roma (Atlas of the breeding birds of Rome), Fratelli Palombi Editori, Roma, 1996.
Clergeau, P., Savard, J. P. L., Mennechez, G., and Falardeau, G.: Bird abundance and diversity along an urban–rural gradient: a comparative study between two cities on different continents, Condor, 100, 413–425, 1998.
Clergeau, P., Croci, S., Jokimäki, J., Kaisanlahti-Jokimäki, M. L., and Dinetti, M.: Avifauna homogenisation by urbanisation: Analysis at different European latitudes, Biol. Conserv., 127, 336–344, 2006a.
Comber, A. J.: Land Cover or Land Use?, J. Land Use Sci., 3, 199–201, 2008.
Cramp, S.: The complete birds of the western Palaearctic, Optimedia, Oxford Univ. Press, Oxford, 1998.
Croci, S., Butet, A., Georges, A., Aguejdad, R., and Clergeau, P.: Small urban woodlands as biodiversity conservation hot-spot: a multi-taxon approach, Lands. Ecol., 23, 1171–1186, 2008.
Díaz, S. and Cabido, M.: Vive la différence: plant functional diversity matters to ecosystem processes, Trends Ecol. Evol., 16, 646–655, 2001.
Du Toit, M. J. and Cilliers, S. S.: Aspects influencing the selection of representative urbanization measures to quantify urban-rural gradients, Lands. Ecol., 26, 169–181, 2011.
Evans, K. L., Chamberlain, D. E., Hatchwell, B. J., Gregory, R. D., and Gaston, K. J.: What makes an urban bird?, Glob. Change Biol., 17, 32–44, https://doi.org/10.1111/j.1365-2486.2010.02247.x, 2011.
Faeth, S. H., Saari, S., and Bang, C.: Urban Biodiversity: Patterns, Processes and Implications for Conservation, eLS 2012, John Wiley & Sons Ltd, Chichester, 2012.
Fernández-Juricic, E.: Bird community composition patterns in urban parks of Madrid: the role of age, size and isolation, Ecol. Res., 15, 373–383, 2000.
Gotelli, N. J. and Entsminger G. L.: EcoSim: Null models software for ecology. Version 7.0. Acquired Intelligence Inc. & Kesey-Bear, http://homepages.together.net/ gentsmin/ecosim.htm, 2001.
Graham, J. H. and Duda, J. J.: The humpbacked species richness-curve: a contingent rule for community ecology, Int. J. Ecol., 2011, 1–15, https://doi.org/10.1155/2011/868426, 2011.
Johnson, D. H.: In defense of indices: the case of bird surveys, J. Wildlife Manage., 72, 857–868, 2008.
Jokimäki, J., Kaisanlahti-Jokimäki, M. L., Sorace, A., Fernández Juricic, E., Rodriguez Prieto, I., and Jimenez, M. D.: Evaluation of the "safe-nesting zone" hypothesis across an urban gradient: a multi-scale study, Ecography, 28, 59–70, 2005.
Kark, S., Iwaniuk, A., Schalimtzek, A., and Banke, E.: Living in the city: can anyone become an "urban exploiter"?, J. Biogeogr., 34, 638–651, 2007.
Llop, E., Pinho, P., Matos, P., Pereira M. J., and Branquinho, C.: The use of lichen functional groups as indicators of air quality in a Mediterranean urban environment, Ecol. Indic., 13, 215–221, 2012.
Marzluff, J. M.: Worldwide urbanization and its effects on birds, in: Avian Ecology in an urbanizing World, edited by: Marzluff, J. M., Bowman, R., and Donnelly, R., Kluwer Academic, Norwell, Massachusetts, USA, 19–47, 2001.
Matson, P.: The use of urban gradients in ecological studies, Ecology, 71, p. 1231, 1990.
McDonnell, M. J. and Hahs, A. K.: The use of gradient analysis studies in advancing our understanding of the ecology of urbanizing landscapes: current status and future directions, Land. Ecol., 23, 1143–1155, 2008.
McDonnell, M. J., Pickett, S. T. A., and Pouyat, R. B.: The application of the ecological gradient paradigm to the study of urban effects, in: Humans as Components of Ecosystems, edited by: McDonnell, M. J. and Pickett, S. T. A., Springer-Verlag, New York, USA, 175–189, 1993.
McDonnell, M. J., Pickett, S. T. A., Groffman, P., Bohlen, P., Pouyat, R. V., Zipperer, W. C., Parmelee, R. V., Carreiro, M. M., and Medley, K.: Ecosystem processes along an urban-rural gradient, Urban Ecosys., 1, 21–36, 1997.
McKinney, M. L.: Urbanization as a major cause of biotic homogenization, Biol. Conserv., 127, 247–260, 2006.
Melles, S., Glenn, S., and Martin, K.: Urban bird diversity and landscape complexity. Species-environment associations along a multiscale habitat gradient, Conserv. Ecol., 7, 271–279, 2003.
Osborne, P. and Osborne, L.: The contribution of nest site characteristics to breeding-success among Blackbirds
Turdus merula, Ibis, 122, 512–517, 1980.
Pautasso, M., Böhning-Gaese, K., Clergeau, P., Cueto, V. R., Dinetti, M., Fernández-Juricic, E., Kaisanlahti-Jokimäki, M.-L., Jokimäki, J., McKinney, M. L., Sodhi, N. S., Storch, D., Tomialojc, L., Weisberg, P. J., Woinarski, J., Fuller, R. A., and Cantarello, E.: Global macroecology of bird assemblages in urbanized and semi-natural ecosystems, Global Ecol. Biogeogr., 20, 426–436, 2010.
Pellissier, V., Cohen, M., Boulay, A., and Clergeau, P.: Birds are also sensitive to landscape composition and configuration within the city centre, Landsc. Urban Plan., 104, 181–188, 2012.
Ricotta, C., Celesti-Grapow, C., Avena, G., and Blasi, C.: Topological analysis of the spatial distribution of plant species richness across the city of Rome (Italy) with the echelon approach, Landsc. Urban Plan., 57, 69–76, 2001.
Root, R. B.: The Niche Exploitation Pattern of the Blue-Gray Gnatcatcher, Ecol. Monogr., 37, 317–350, https://doi.org/10.2307/1942327, 1967.
Sattler, T., Duelli, P., Obrist, M. K., Arlettaz, R., and Moretti, M.: Response of arthropod species richness and functional groups to urban habitat structure and management, Lands. Ecol., 25, 941–954, 2010.
Shwartz, A., Shirley, S., and Kark, S.: How do habitat variability and management regime shape the spatial heterogeneity of birds within a large Mediterranean urban park?, Landsc. Urban Plan., 84, 219–229, 2008.
Simberloff, D. and Dayan, T.: The functional group concept and the structure of ecological communities, Annu. Rev. Ecol. Syst., 22, 115–143, 1991.
Siriwardena, G. M., Cooke, I. R., and Sutherland, W. J.: Landscape, cropping and field boundary influences on bird abundance, Ecography, 35, 162–173, 2012.
Sorace, A.: Value to wildlife of urban-agricultural parks: a case study from Rome urban area, Environ. Manage., 28, 547–560, 2001.
Sorace, A. and Gustin, M.: Bird species of conservation concern along urban gradients in Italy, Biodiv. Conserv., 19, 205–221, 2009.
Sorace, A., Gustin, M., Calvario, E., Ianniello, L., Sarrocco, S., and Carere, C.: Assessing bird communities by point counts: repeated sessions and their duration, Acta Ornithol., 35, 197–202, 2000.
Statsoft Inc.: STATISTICA (data analysis software system), version 8.0, Statsoft Inc., Tulsa, Oklaoma, 2008.
Strohbach, M. W., Haase, D., and Kabisch N.: Birds and the city: urban biodiversity, land use, and socioeconomics, Ecol. Soc., 14, 31, http://www.ecologyandsociety.org/vol14/iss2/art31/, 2009.
Taffon, D. and Battisti, C.: Breeding bird communities and ecotope niche breadth of the Species in a heterogeneous landscape of Central Italy, Riv. Ital. Ornitol., 75, 129–139, 2006.
Tews, J., Brose, U., Grimm, V., Tielbörger, K., Wichmann, M. C., Schwager, M., and Jeltsch, F.: Animal species diversity driven by habitat heterogeneity/diversity: the importance of keystone structures, J. Biogeogr., 31, 79–92, 2004.
Tilman, D.: Functional diversity, in: Encyclopedia of Biodiversity, edited by: Levin, S. A., Vol. 5, Academic Press, New York, 2001.
Vignoli, L., Mocaer, I., Luiselli, L., and Bologna, M. A.: Can a large metropolis sustain complex herpetofauna communities? An analysis of green space areas suitability in Rome, Anim. Conserv., 12, 456–466, 2009.
Whittaker, R. H.: Gradient analysis of vegetation, Biol. Rev., 42, 207–264, 1967.
Wiens, J. A.: The Ecology of Bird Communities 1: foundation and patterns, Cambridge University Press, Cambridge, 1997.
Wilkinson, D. M.: The disturbing history of intermediate disturbance, Oikos, 84, 145–147, 1999.
