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The aim of this study was to assess the improvement of plant species distribution models based on coarse-grained occurrence data when adding lithologic data to climatic models. The distributions of 40 woody plant species from continental Spain were modelled. A logistic regression model with climatic predictors was fitted for each species and compared to a second model with climatic and lithologic predictors. Improvements on model likelihood and prediction accuracy on validation subsamples were assessed, as well as the effect of calcicole-calcifuge habit on model improvement. Climatic models had reasonable mean prediction accuracy, but adding lithologic data improved model likelihood in most cases and increased mean prediction accuracy. Therefore, we recommend utilizing lithologic data for species distribution models based on coarse-grained occurrence data. Our data did not support the hypothesis that calcicole-calcifuge habit may explain model improvement when adding lithologic data to climatic models, but further research is needed.Key words: environmental niche modelling, chorologic atlas, calcicole-calcifuge habit. ResumenLa información litológica mejora los modelos de distribución de especies de plantas basados en datos de baja resolución espacialEl objetivo de este estudio es evaluar la mejora que supone la incorporación de la litología a modelos climáticos de distribución de especies basados en datos de baja resolución espacial. La zona de estudio es la España peninsular. Se ha ajustado un modelo de regresión logística con variables climáticas para cada una de las 40 especies vegetales consideradas y se ha comparado a un segundo modelo con variables climáticas y litológicas. Se ha evaluado la mejora en la verosimilitud y la capacidad predictiva en submuestras de validación, así como el efecto del grado de preferencia de las especies por suelos calcáreos o silíceos en dicha mejora. Los modelos climáticos ofrecen una capacidad predictiva media razonablemente buena, pero la adición de la litología aumenta la verosimilitud del modelo en la mayoría de los casos y la precisión media de las predicciones aumentan significativamente. Se recomienda utilizar información litológica para los modelos de distribución de especies de plantas basados en datos de baja resolución espacial. Con los datos usados no se puede aceptar la hipótesis de que el grado de preferencia de las especies por suelos calcáreos o silíceos explica las diferencias entre especies en la mejora de los modelos debido a la incorporación de información litológica, pero este aspecto debe ser estudiado con más profundidad en futuras investigaciones.Palabras clave: modelización de nicho ecológico, atlas corológicos, calcífugas, calcícolas.

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The interrelation between bedrock lithology and the geometry of the drainage systems has been widely studied in the last decades. The quantification of this linkage has not yet been clearly established. Several studies have selected river basins or regularly shaped areas as study units, assuming them to be lithologically homogeneous. This study considered irregular distributions of rock types, establishing areas of the soil map (1:25,000) with the same lithologic information as study units. The tectonic stability and the low climatic variability of the study region allowed effective investigation of the lithologic controls on the drainage networks developed on the plutonic rocks, the metamorphic rocks, and the sedimentary materials existing in the study area. To exclude the effect of multiple in‐ and outflows in the lithologically homogeneous units, we focused this study on the first‐order streams of the drainage networks. The geometry of the hydrologic features was quantified through traditional metrics of fluvial geomorphology and scaling parameters of fractal analysis, such as the fractal dimension, the reference density, and the lacunarity. The results demonstrate the scale invariance of both the drainage networks and the set of first‐order streams at the study scale and a relationship between scaling in the lithology and the drainage network.