What can physical, biotic and chemical features of a tree hollow tell us about their associated diversity?

Tree hollows are keystone structures for saproxylic fauna and host numerous endangered species. However, not all tree hollows are equal. Many variables including physical, biotic and chemical ones, can characterise a tree hollow, however, the information that these could provide about the saproxylic diversity they harbour has been poorly explored. We studied the beetle assemblages of 111 Quercus species tree hollows in four protected areas of the Iberian Peninsula. Three physical variables related to tree hollow structure, and two biotic ones (presence of Cetoniidae and Cerambyx species recognised as ecosystem engineers) were measured in each hollow to explore their relative effect on beetle assemblages. Moreover, we analysed the chemical composition of the wood mould in 34 of the hollows, in order to relate beetle diversity with hollow quality. All the environmental variables analysed (physical and biological) showed a significant influence on saproxylic beetle assemblages that varied depending on the species. Furthermore, the presence of ecosystem engineers affected both physical and chemical features. Although wood mould volume, and both biotic variables could act as beetle diversity surrogate, we enhance the presence of Cetoniidae and Cerambyx activity (both easily observable in the field) as indicator variables, even more if both co-occur as each affect to different assemblages. Finally, assimilable carbon and phosphorous contents could act as indicator for past and present beetle activity inside the cavity that could become a useful tool in functional diversity studies. However, an extension of this work to other taxonomic groups would be desirable.

El lenguaje gráfico de Eduardo Chillida como aportación conceptual para la identidad tipográfica de la Universidad del País Vasco —UPV/EHU—

Este proyecto de investigación financiado por la Universidad del País Vasco/Euskal Herriko Unibertsitatea —UPV/EHU-PES 11/31—, a través de su programa de investigación estratégica, tiene como objetivo la creación de la tipografía de identidad visual corporativa de la Universidad del País Vasco —UPV/EHU—, cuyo inicio conceptual para dotar de unas características de identidad visual corporativa a la UPV/EHU, ha sido planteado desde las especulaciones estéticas sobre la forma, materializadas por Eduardo Chillida. En la producción gráfica de este artista encontramos una sutil coincidencia con principios vitales para la creación tipográfica, en cuanto al planteamiento de formas dinámicas y constructivas, en las que el rigor geométrico es vencido por una suerte de organicidad que parte del núcleo mismo de la estructura —«cursus»—, por: la fuerza vital que imprime la acción modulada del gesto —«ductus»—; por la dialéctica entre lo lleno y lo vacío —forma/contraforma—, por el impulso y la espontaneidad — carácter—, o por la afirmación de un lenguaje plástico en la cultura diferenciada del medio en el que se vive —identidad—.