One of the best documented effects of climate change on biodiversity are shifts in phenology. However, long-term data quantifying and projecting the expected changes in phenology associated with climate warming are limited to a few well-recorded areas in the world. In the absence of temporal recording, an alternative approach is to determine the phenological response of species along marked gradients in climate or along latitudinal or altitudinal transects (space-for-time substitution). We studied the phenology (timing and duration of the flight period) of butterflies in 2006 along an altitudinal gradient (900-1680 m; estimated temperature lapse rate = -6.6°C/km) in the Serranía de Cuenca (central Spain) at the assemblage and individual species levels. Timing of the flight period was later for assemblages at high than at low altitudes. A similar trend of an increasing delay in the flight period with altitude was recorded for some individual species. However, there were also some exceptions to this pattern regardless of the number of sites and the altitudinal ranges of the species, suggesting possible local adaptation to regional climate. The duration of the flight period was shorter at high altitudes for assemblages, but this trend was not mirrored in the response of individual species. The results partly support substituting space-for-time when assessing the potential effect of climate change on phenophases such as the timing of the flight period, but we recommend extreme caution in extrapolating the results in the absence of information on how the responses of populations differ. and Juan Ignacio De Arce Crespo, David Gutiérrez.
Commercial chambers for in vivo gas exchange are usually designed to measure on vascular plants, but not on cryptogams and other organisms forming biological soil crusts (BSCs). We have therefore designed two versions of a chamber with different volumes for determining CO2 exchange with a portable photosynthesis system, for three main purposes: (1) to measure in situ CO2 exchange on soils covered by BSCs with minimal physical and microenvironmental disturbance; (2) to acquire CO2-exchange measurements comparable with the most widely employed systems and methodologies; and (3) to monitor CO2 exchange over time. Different configurations were tested in the two versions of the chamber and fluxes were compared to those measured by four reference commercial chambers: three attached to two respirometers, and a conifer chamber attached to a portable photosynthesis system. Most comparisons were done on biologically crusted soil samples. When using devices in a closed system, fluxes were higher and the relationships to the reference chambers were weaker. Nevertheless, high correlations between our chamber operating in open system and measurements of commercial respiration and photosynthetic chambers were found in all cases (R2 > 0.9), indicating the suitability of the chamber designed for in situ measurements of CO2 gas exchange on BSCs., M. Ladrón De Guevara, R. Lázaro, J. L. Quero, S. Chamizo, F. Domingo., and Obsahuje bibliografii