Efectos geográficos y ambientales sobre la distribución de las aves forestales ibéricas

Abstract

RESUMENEl efecto península es un patrón según el cual la riqueza de especies disminuye en función de la distancia al continente. Sin embargo, este patrón es frecuentemente enmascarado por la incidencia de variables ambientales. En este trabajo estudiamos el efecto relativo de la ubicación geográfica y de un conjunto de variables ambientales (temperatura, precipitación, cobertura forestal…) sobre la distribución de la riqueza de especies de aves forestales en España peninsular. Los resultados sugieren que tanto la posición geográfica como las condiciones ambientales afectan a la distribución de la riqueza de aves. También se estudia si estos resultados varían en función de las características particulares de las áreas estudiadas. Para esta segunda aproximación se definieron dos corredores de similar longitud ubicados entre las costas atlánticas y mediterráneas y las montañas interiores. El corredor Atlántico mostró una elevada homogeneidad ambiental en toda su extensión, mientras el corredor Mediterráneo presentó un marcado gradiente desde las áreas más húmedas del norte a las condiciones más secas del sur. Los resultados muestran que en el corredor Atlántico la distancia al continente, no las condiciones ambientales, fue la principal predictora de la riqueza de especies, mientras que en el corredor Mediterráneo las variables ambientales fueron mejores predictoras de la distribución de la riqueza. Estos resultados son utilizados para discutir algunos aspectos biogeográficos y metodológicos de la distribución de aves forestales en la Península Ibérica. Palabras clave: efecto península, aves forestales, riqueza de especies, Península Ibérica. ABSTRACT Geographic and environmental effects on the distribution of Iberian forest bird richnessThe peninsular effect is a biogeographical rule according to which species richness decreases as a function from the distance to the mainland base of peninsulas. However, this pattern is frequently obscured by the effect of environmental variables. In this paper we study the relative effect of the geographic location and some environmental variables on the distribution of the richness of Iberian forest birds. Results suggest that both the geographic location and some environmental variables (temperature, precipitation, forest coverage…) affect the species richness. We have also explored if these results can change according to the particular features of the study areas. To approach this, we defined two corridors of a similar length. The Atlantic corridor was quite homogeneous in the study environmental variables while the Mediterranean showed a sharp gradient from moist northern to dry south. Results showed that in the Atlantic corridor, distance to continent and not environmental variables were the main correlates to species richness while in the Mediterranean corridor environmental variables were the best correlates to richness distributions. These results are used to discuss some methodological and biogeographical aspects of the forest bird distribution across the Iberian Penins...

Relative influence of habitat heterogeneity, climate, human disturbance, and spatial structure on vertebrate species richness in Spain

“…We expected species richness to increase towards the Pyrenees (i.e., northwards, contrary to the general pattern, Willig et al 2003) within mainland Spain, due to a peninsular effect, as was found in passerines (Carrascal and Lobo 2003;Ramı´rez and Tellerı´a 2003;Gonza´lez-Taboada et al 2007). Indeed, when we controlled for other variables, we found these taxa displayed complex relationships with latitude (although not significant for amphibians), although the relationships were of different magnitudes ( Table 2).…”

Wind power plants and the conservation of birds and bats in Spain: a geographical assessment

“…However, high species richness in northern Spain has been described in vascular plants, butterflies, birds, and mammals (Martín and Gurrea 1990;Lobo et al 2001;Ramírez and Tellería 2003;Carrascal and Lobo 2003;González-Taboada et al 2007). In fact, we reported a significant correlation between the distribution of our particular set of flying vertebrates and the total number of bird and mammals species in Spain.…”

Determining high value areas for steppe birds in Spain: hot spots, complementarity and the efficiency of protected areas

“…The establishment of protected space networks on the basis of the presence of Xagship or umbrella species has been found to be poorly eVective before (Kerr 1997;Andelman and Fagan 2000). It is also possible that within Spain priority in SPA designation has been given to other bird groups, such as forest communities, for which the eVectiveness of protection has been shown to be appreciably superior (Ramírez 2004). In any event, it must be borne in mind that just because a grid cell does not form part of the top 5% does not mean that it lacks conservation value.…”

“…This percentage has been used in previous works (Prendergast et al 1993a;Williams et al 1996;Sólymos and Fehér 2005;Ramírez 2004) to represent the minimum area necessary to encompass the most important zones in a territory.…”