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D. S. de Ron et al. 2010. Habitat suitability models for two species of forest raptors in Catalonia
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Habitat suitability models for two species of forest raptors in Catalonia.
Methodological consequences related with different scales and data
sources
David Sánchez de Ron 1 , Lluís Brotons 2 , Santiago Saura 3 & José M. García del Barrio 1,4
1
CIFOR-INIA, Madrid, Spain
2
Centre Tecnològic Forestal de Catalunya, Solsona, Spain
3 ETSIM-UPM Madrid, Spain
4
Instituto Universitario Investigación Gestión Forestal Sostenible, UVA-INIA, Spain
Abstract
Species distribution along a territory is a function of different environmental variables that
changes in space and time. In this communication we use GIS based information from different
sources and at different scales (1x1 km 2 and 10x10 km 2 ) for elaborating habitat suitability
models of two forest raptors species (Buteo buteo and Accipiter gentilis) along a north-south
gradient in Cataluña. The area of study has an extent of 7000 km 2 . Forest raptors species
presence/absence data on 679 1x1 km 2 grid cells of the Catalan Breeding Bird Atlas, and
Spanish Forest Map at a scale 1:50,000 are the main information sources. Logistic regression
methods have been essayed for comparison across different scales. Unexpectedly, preliminary
results show no relation between variables like land use type or diversity of habitats and raptors
presence at 1x 1 km 2 , and this relationship is only significant for Buteo buteo at 10 x 10 km 2
scale.
Keywords: Habitat suitability models, land uses, logistic regression, changing scales.
1. Introduction
Animal species related to forest habitats are dependent on habitat extension but on habitat
quality as well. Advances in knowing species distribution and habitat requirements are essential
for studies of population genetics, evolutionary and conservation biology, biodiversity
maintenance and territorial planning, among others. Recent georeferenced information about not
only species distribution in Spain, but also related to climate, lithology, changes in land uses or
historical disturbances (wild fires, floods, wind storms) at different scales are valuable data
sources that contribute to the elaboration of habitat suitability models that are the basis for
connectivity or habitat fragmentation analysis (Pascual-Hortal & Saura, 2008). Specialist
species have been affected by reduction of habitat extension and population fragmentation (see
Farhig, 2001; Lindenmayer, et al, 2003; Alderman et al, 2005) with the consequence of
reduction on effective population levels. Spanish forest raptors are not the exception, and a
proper knowledge of habitat requirements and habitat suitability is needed. Underlying reasons
for explain mismatch between potential and real distribution of a species are scale dependent,
and the explanation of this dependence is one of the goals of habitat suitability models –HSM
hereafter- (Ottaviani et al, 2004; Guisan and Thuiller, 2005).
In a previous paper (García del Barrio et al, 2009) we essayed HSM for two forest raptors on
two forest districts of central-east Spain with presence/absence data at 10x10 km 2 scale. The
aim of this paper is to compare the performance of HSM at changing scales and using different
data sources. Forest raptors species chosen are goshawk (Accipiter gentilis) and common
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.