Large-scale determinants of diversity across Spanish forest habitats: accounting for model uncertainty in compositional and structural indicators

E. Martín-Queller, O. Torras, I. Alberdi, J. Solana, S. Saura


An integral understanding of forest biodiversity requires the exploration of the many aspects it comprises and of the numerous potential determinants of their distribution. The landscape ecological approach provides a necessary complement to conventional local studies that focus on individual plots or forest ownerships. However, most previous landscape studies used equally-sized cells as units of analysis to identify the factors affecting forest biodiversity distribution. Stratification of the analysis by habitats with a relatively homogeneous forest composition might be more adequate to capture the underlying patterns associated to the formation and development of a particular ensemble of interacting forest species. Here we used a landscape perspective in order to improve our understanding on the influence of large-scale explanatory factors on forest biodiversity indicators in Spanish habitats, covering a wide latitudinal and altitudinal range. We considered six forest biodiversity indicators estimated from more than 30,000 field plots in the Spanish national forest inventory, distributed in 213 forest habitats over 16 Spanish provinces. We explored biodiversity response to various environmental (climate and topography) and landscape configuration (fragmentation and shape complexity) variables through multiple linear regression models (built and assessed through the Akaike Information Criterion). In particular, we took into account the inherent model uncertainty when dealing with a complex and large set of variables, and considered different plausible models and their probability of being the best candidate for the observed data. Our results showed that compositional indicators (species richness and diversity) were mostly explained by environmental factors. Models for structural indicators (standing deadwood and stand complexity) had the worst fits and selection uncertainties, but did show significant associations with some configuration metrics. In general, biodiversity increased in habitats covering wider topographic ranges and comprising forest patches with more complex shapes. Patterns in other relationships varied between indicators (e.g. species richness vs. diversity), or even were opposed (trees vs. shrubs). Our study (1) allowed deepening the understanding of biodiversity patterns in a large set of Spanish forest habitats and (2) highlighted the increasing complexity of identifying common landscape conditions favouring forest biodiversity as the range of analysed biodiversity aspects is widened beyond the more commonly assessed species richness indicators.


árboles muertos en pie; configuración espacial del hábitat; Criterio de Información de Akaike; diversidad de Margalef y Shannon; ecología del paisaje; inventario forestal nacional.

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Baessler C., Klotz S., 2006. Effects of changes in agricultural land-use on landscape structure and arable weed vegetation over the last 50 years. Agric Ecosyst Environ 115(1-4), 43-50.

Begon M., Townsend C.R., Harper J.L., 2006. Ecology. From individuals to ecosystems. Blackwell Publishing, Oxford, UK. 738 pp.

Bruun H.H., Moen J., Angerbjörn A., 2003. Environmental correlates of meso-scale plant species richness in the province of Härjedalen, Sweden. Biodivers Conserv 12, 2025-2041.

Burnham K.P., Anderson D.R., 2002. Model Selection and Multimodel Inference: a practical information-theoretical approach. Springer-Verlag, New York, US. 488 pp.

Castro-Parga I., Saiz J.C.M., Humphies C.J., Williams P.H., 1996. Strengthening the natural and national park system of Iberia to conserve vascular plants. Bot J Linn Soc 121(3), 189-205

Cost E43, 2004-2008. Harmonisation of national forest inventories in Europe: techniques for common reporting [on line]. Available in [2 Nov 2010].

Currie D.J., Paquin V., 1987. Large-scale biogeographical patterns of species richness of trees. Nature 329, 326- 327.

Dauber J., Hirsch M., Simmering D., Waldhard R., Otte A., Wolters V., 2003. Landscape structure as an indicator of biodiversity: matrix effects on species richness. Agric Ecosyst Environ 98, 321-329.

Diaz-Varela E.R., Marey-Pérez M.F., Rigueirorodríguez A., Álvarez-Álvarez P., 2009. Landscape metrics for characterization of forest landscapes in a sustainable management framework: potential application and prevention of misuse. Ann For Sci 66(3), 301.

Duelli P., Obrist M.K., 2003. Biodiversity indicators: The choice of values and measures. Agric Ecosyst Environ 98(1-3), 87-98.

Fahrig L., 2003. Effects of habitat fragmentation on biodiversity. Annu Rev of Ecol, Evol Syst 34, 487-515.

Fernández-Juricic E., 2000. Forest fragmentation affects winter flock formation of an insectivorous guild. Ardea 88, 235-241.

Field R., O'brien E.M., Whittaker R.J., 2005. Global models for predicting woody plant richness from climate: development and evaluation. Ecology 86, 2263-2277.

Field R., Hawkins B.A., Cornell H., Currie D.J., Diniz-Filho A.F., Guégan J., Kaufman D.M., Kerr J.T., Mittelbach G.G., Oberdorff T., O'brien E.M., Turner J.R.G., 2009. Spatial speciesrichness gradients across scales: a meta-analysis. J Biogeogr 36, 132-147.

García López J.M., Allué Camacho C., 2008. Phytoclimatic versatility and potential diversity of natural arboreal forest cover in peninsular Spain. Forest Systems 17(3), 297-307.

Gil-Tena A., Brotons L., Saura S., 2009. Mediterranean forest dynamics and forest bird distribution changes in the late 20th century. Glob Change Biol 15, 474-485.

Heikkinen R.K., Neuvonen S., 1997. Species richness of vascular plants in the subarctic landscape of northern Finland: Modelling relationships to the environment. Biodivers Conserv 6(9), 1181-1201.

Honnay O., Hermy M., Coppin P., 1999. Effects of area, age and diversity of forest patches in Belgium on plant species richness, and implications for conservation and reforestation. Biol Conserv 87(1), 73-84.

Honnay O., Piessens K., Van Landuyt W., Hermy M., Gulinck H., 2003. Satellite based land use and landscape complexity indices as predictors for regional plant species diversity. Landscape Urban Plan 63, 241-250.

Hooper D.U., Chapin F.S., Ewel J.J., Hector A., Inchausti P., Lavorel S., Lawton J.H., Lodge D.M., Loreau M., Naeem S., Schmid B., Setälä H., Symstad A.J., Vandermeer J., Wardle D.A., 2005. Effects of biodiversity on ecosystem functioning: a consensus of current knowledge. Ecol Monogr 75, 3-35.

Huston M.A., 1994. Biological diversity: the coexistence of species on changing landscapes. Cambridge University Press, Cambridge, UK., 681 pp.

Juutinen A., Luque S., Mönkkönen M., Vainikainen N., Tomppo E., 2008. Cost-effective forest conservation and criteria for potential conservation targets: a Finish case study. Environ Sci Policy 11(7), 613-626.

Lafortezza R., Coomes D.A., Kapos V., Ewers R.M., 2010. Assessing the impacts of fragmentation on plant communities in New Zealand: scaling from survey plots to landscapes. Global Ecolo Biogeogr 19(5), 741-754.

Leathwick J.R., Burns B.R., Clarkson B.D., 1998. Environmental correlates of tree alpha-diversity in New Zealand primary forests. Ecography 21, 235-246.

Lindenmayer D.B., Margules C.R., Botkin D.B., 2000. Indicators of biodiversity for ecologically sustainable forest management. Conserv Biol 14, 941-950.

Lloret F., Lobo A., Estevan H., Maisongrande P., Vayreda J., Terradas J., 2007. Woody plant richness and NDVI response to drought events in Catalonian (Northeastern Spain) forests. Ecology 88(9), 2270-2279. PMid:17918405

Lobo J.M., Castro. I., Moreno J.C., 2001. Spatial and environmental determinants of vascular plant species richness distribution in the Iberian Peninsula and Balearic Islands. Biol J Linn Soc 73, 233-253.

Loreau M., Naeem S., Inchausti P., Bergtsson J., Grime J.P., Hector A., Hooper D.U., Huston M.A., Raffaelli D., Shmid B., Tilman D., Wardle D.A., 2001. Biodiversity and ecosystem functioning: current knowledge and future challenges. Science 294, 804-808. PMid:11679658

Magurran A.E., 1989. Diversidad ecológica y su medición. Ediciones Vedrà, Barcelona, Spain. 200 pp.

MCPFE, 2003. State of Europe's Forests: The MCPFE report on sustainable forest management in Europe. Ministerial Conferenc on Protection of Forests in Euripe Liaison Unit, Viena, Austria.

Ministerio De Fomento, 1999. Modelo digital del terreno 1: 25000. Dirección General del Instituto Geográfico Nacional, Centro Nacional de Información Geográfica, Madrid, Spain.

Ministerio De Medio Ambiente, 1997-2007. Tercer Inventario Forestal Nacional. Dirección General de Conservación de la Naturaleza, Madrid, Spain. [In Spanish].

Montoya D., Zavala M.A., Rodríguez M.A., Purves D.W., 2008. Animal versus wind dispersal and the robustness of tree species to deforestation. Science 320, 1502-1504. PMid:18535208

Moreno-Saiz J., Lobo J., 2008. Iberian-Balearic fern regions and their explanatory variables. Plant Ecol 198(2), 149-67

Moser D., Zechmeister H.G., Plutzar C., Sauberer N., Wrbka T., Grabherr G., 2002. Landscape patch shape complexity as an effective measure for plant species richness in rural landscapes. Landscape Ecol 17(7), 657-69.

Newton A.C., Kapos V., 2002. Biodiversity indicators in national forest inventories. In: Unasylva 210. [Online Journal]. Available at: 0. [2 Nov 2010].

Ninyerola M., Pons X., Roure J.M., 2005. Atlas climático digital de la Península Ibérica. Metodología y aplicaciones en bioclimatología y geobotánica. Universidad Autónoma de Barcelona, Bellaterra, Spain. [In Spanish].

Noss R.F., 1990. Indicators for monitoring biodiversity: a hierarchical approach. Conservation Biology 4, 355-364.

O'Brien E.M., 1993. Climatic gradients in woody plant species richness: towards an explanation based on an analysis of southern Africa's woody flora. J Biogeogr 20, 181-198.

O'Brien E.M. 1998. Water-energy dynamics, climate, and prediction of woody plant species richness: an interim general model. J Biogeogr 25, 379-398.

O'Brien E.M., Field R., Whittaker R.J., 2000. Climatic gradients in woody plant (tree and shrub) diversity: water-energy dynamics, residual variation, and topography. Oikos 89, 588-600.

Ortega M., Bunce R.G.H., García-Del-Barrio J.M., Elena-Rosselló R., 2008. The relative dependence of Spanish landscape pattern on environmental and geographical variables over time. Forest systems 17(2), 114-129.

Pausas J.G., 1994. Species richness patterns in the understorey of Pyrenean Pinus sylvestris forests. J Veg Sci 5, 517-524.

Pausas J.G., Carreras J., Ferre A., Font X., 2003. Coarse-scale plant species richness in relation to environmental heterogeneity. J Veg Sci 14, 661-668.

Rex K.D., Malanson G.P., 1990. The fractal shape of riparian forest patches. Landscape Ecol 4(4), 249-258.

Rey-Benayas J.M., 1995. Patterns of diversity in the strata of boreal forest in British Columbia. J Veg Sci 6, 95-98.

Rey-Benayas J.M., Scheiner S.M., 2002. Plant diversity, biogeography and environment in Iberia: patterns and possible causal factors. J Veg Sci 13, 245-258.[0245:PDBAEI]2.0.CO;2

Saura S., Carballal P., 2004. Discrimination of native and exotic forest patterns through shape irregularity indices: an analysis in the landscapes of Galicia, Spain. Landscape Ecol 19(6), 647-662.

Saura S., Torras O., Gil-Tena A., Pascual L., 2008. Shape irregularity as an indicator of forest biodiver sity and guidelines for metric selection. In: Patterns and processes in forest landscapes: multiple use and sustainable management (Lafortezza R., Chen J., Sanesi G., Crow T.R., eds). Springer, New York, US. 167-189.

Smith A.C., Koper N., Francis C.M., Fahrig L., 2009. Confronting collinearity: comparing methods for disentangling the effects of habitats loss and fragmentation. Landscape Ecol 24, 1271-1285.

Stephens P.A., Buskirk S.W., Hayward G.D., Del Río C.M., 2005. Information theory and hypothesis testing: a call for pluralism. J Appl Ecol 42, 4-12.

Torras O., Gil-Tena A., Saura S., 2008. How does forest landscape structure explain tree species richness in a Mediterranean context? Biodivers Conserv 17(5), 1227-1240.

Torras O., Martín-Queller E., Saura S., 2009. Relating landscape structure, environment and management to biodiversity indicators estimated from forest inventory data in Catalonia. Forest systems 18(3), 322-337.

Vetaas O.R., Ferrer-Castán D., 2008 Patterns of woody plant species richness in the Iberian Peninsula: environmental range and spatial scale. J Biogeogr 35(10), 1863-1878.

Vilà M., Vayreda J., Comas L., Ibáñez J.J., Mata T., Obón B., 2007. Species richness and wood production: a positive association in Mediterranean forests. Ecol Lett 10, 241-250. PMid:17305807

Whittaker R.J., Nogués-Bravo D., Araújo M.B., 2007. Geographical gradients of species richness: a test of the water-energy conjecture of Hawkins et al. (2003) using European data for five taxa. Global Ecol Biogeogr 16, 76-89.

Wohlgemuth T., 1998. Modelling floristic species richness on a regional scale: a case study in Switzerland. Biodivers Conserv 7, 159-177

DOI: 10.5424/fs/2011201-10910