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Mediterranean annual grasslands are species-diverse ecosystems of high economic and ecological value. CO2 and water fluxes in these grasslands are triggered by the first rains in autumn, after a long hot and dry summer. Climate change scenarios project altered rainfall patterns, such as prolonged dry season into the autumn, while simultaneously nitrogen (N) deposition is increasing globally. However, how these global change drivers will interact to affect Mediterranean grassland CO2, water fluxes and productivity is still unclear. In a greenhouse experiment, we subjected the seedbank of an annual Mediterranean grassland to a factorial treatment, by prolonging the dry season by 0 days (i.e. no autumn drought), 50 days and 100 days and crossing these drought treatments with two levels of N deposition: no N and N addition. A delayed onset of the rain season, i.e., a prolonged dry season, induced lower CO2 and water fluxes throughout the growing season and a lower aboveground biomass by the end of the study period. However, N addition attenuated the effects on NEE, Reco and GPP, but did not affect aboveground biomass or functional group composition. A prolonged dry season also lowered the productivity of forbs, the dominant functional group in our grassland. Our results anticipate important effects of interacting global change drivers on Mediterranean grassland functioning.

Forest certification is a conservation tool, which aims to promote the sustainable management and conservation of forest ecosystems. Establishing set-aside or lower intervention conservation zones to promote biodiversity conservation is a requisite of forest certification. We tested the effects of conservation zones on the tree biometrics and regeneration, as well as on the taxonomic, functional, and structural diversity of the shrub and herb understory, in Mediterranean oak woodlands. We also assessed how oak biometrics, regeneration and understory diversity varied among conservation zones established 10, 14, and 20 years before our sampling dates. Oak regeneration tended to be higher in conservation zones than in controls, but results varied with the age of conservation zones. For example, the abundance of oak seedlings and saplings was higher in 10-year-old conservation zones than in those established 20 years ago. Abundance of young oak trees was higher in 14-year-old conservation zones than in 10- and 20-year-old conservation zones. The understory vertical diversity was significantly higher in 14- and 20-year-old conservation zones than in controls. Functional diversity differed significantly between conservation zones and controls, with a higher abundance of late-successional shrubs, namely fleshy-fruited species in 20-year-old conservation zones. The plant species composition of the shrub and the herb understory was most dissimilar between older conservation zones and controls. Additionally, the cover and diversity of the understory herb species decreased with the age of conservation zones. Conservation zones implemented under forest certification increase habitat structural complexity of oak woodlands, which may benefit wildlife species, but there will be trade-offs with the cover and diversity of the herb understory. Forest managers must evaluate such trade-offs when establishing conservation zones in cork oak woodlands under forest certification schemes.

Global change is affecting ecosystems worldwide. Nitrogen (N) deposition is increasing globally and climate change scenarios forecast an increase of prolonged autumn droughts particularly in the Mediterranean regions. Mediterranean grasslands occupy 1.3 million km2 of the terrestrial surface, host high biodiversity values and generate important ecosystem services. Understanding the effects of N deposition and prolonged autumn drought on the productivity and dynamics of Mediterranean grasslands is crucial to support the conservation of these ecosystems in a global change context. We assessed the effects of extended autumn drought and N deposition on the productivity, species diversity, and phenology of a Mediterranean grassland through a manipulative, greenhouse, experiment. We simulated three levels of extended drought: no drought, 50 days and 100 days of drought and two levels of N deposition: no N and N addition, through a factorial design experiment. Severe drought (100 days) affected negatively grassland productivity, through a reduction of the growing season duration and accumulated growing degree days. Moderate drought (50 days) affected productivity negatively but productivity values recovered to levels similar to those of the non-drought treatment. Severe and moderate drought delayed plant phenology decreasing significantly the number of individuals with mature flowers and with fruits or seeds. Plant functional groups responded differently to drought with productivity of forbs, but not productivity of graminoids and legumes, being negatively affected by moderate and severe drought. N addition did not affect grassland productivity, diversity or phenology. Our results anticipate effects of climate change on the productivity and species composition of Mediterranean grasslands.

Parallel multiple aliquot calibration transfer is combined with the use of standardized optically stimulated luminescence signals and evaluation of single aliquot regenerative dose response characteristics, to produce a robust and efficient transfer protocol for mineral samples used in dating and retrospective dosimetry. Transfer was made from an IST-LPSR 60 Co primary air kerma standard to four Riso and Daybreak 90 Sr/ 90 Y irradiators, for quartz or polymineral grains of 90/100–160 μm or 160–250 μm diameter from seven samples. Grains were pretreated by activation, heating, or bleaching, and mounted on 0.5 mm thick aluminium or stainless steel disks, or 0.25 mm thick stainless steel cups. Multiple aliquot conversion coefficients based on parallel irradiations (mGy 60Co per s of 90 Sr/ 90 Y exposure) were corrected for non linearity in dose response using the regenerative measurements, and compared with “single aliquot” coefficients obtained directly from the regenerative, i.e. retrospectively measured, dose responses. Ratios of measured/given β exposure time provide controls: these were close to unity for activated and heated material, which exhibited predose sensitization, and vice versa for optically bleached samples. Parallel multiple aliquot calibration transfer, using OSL integrated over the main signal decay, was found to offer better accuracy and precision than retrospective single aliquot measurements, and was robust for polyminerals as well as quartz. Differences in conversion coefficient between grain-sizes and supports on a given irradiator ranged up to 25% and were specific to the irradiator-support-grainsize permutation. Geometric effects are quantitatively explained by the solid angle subtended at the source by the sample, and the effect of support material (and thickness) by differences in electron backscatter.

Mediterranean oak woodlands are ecosystems of high conservation and socio-economic value that occur in Southwestern Europe, North Africa and California. Oak regeneration failure is occurring in these ecosystems and may be endangering their long-term conservation. Most studies suggest that inadequate management practices may be contributing to oak regeneration failure. Forest certification is a voluntary type of certification, based on third-party auditing of compliance with performance-based sustainable management standards that has been expanding in forest ecosystems worldwide, including in Mediterranean oak woodlands. The Forest Stewardship Council (FSC) certification is the dominant certification scheme in Mediterranean oak woodlands and requires landowners to establish conservation zones in their estates. Conservation zones usually correspond to a tenth of the estate and are primarily managed for biodiversity conservation. In spite of recent studies reporting positive effects of FSC certification and conservation zones on biodiversity and forest structure in tropical regions, its effects on tree regeneration in Mediterranean oak woodlands are unknown. In this study, conducted in Southwestern Europe, we compared the abundance of cork oak (Quercus suber) regeneration and the cover, richness and diversity of Mediterranean shrublands between conservation and non-conservation zones in FSC certified cork oak woodlands. We found that in conservation zones oak regeneration was more abundant and that species richness and diversity of shrubs were significantly higher. Our results suggest that the creation of set-aside areas in cork oak woodlands, such as conservation zones, may help avert the tree regeneration crisis this ecosystem is facing.

Grazing is a global, dominant land use affecting biodiversity and ecosystem processes. In Mediterranean ecosystems grazing is a major ecological and evolutionary driver but, surprisingly, there is little information on the use of grazing as a tool to manage biodiversity in these ecosystems. We conducted an experiment to assess if establishing grazing and small scale grazing-excluded areas would increase plant and invertebrate diversity in a Mediterranean evergreen oak woodland. Plant community traits were different between treatments. Biomass of herbs (176.7 ± 18.3 g m−2 vs 100.4 ± 10.6 g m−2) and litter (291.0 ± 38.3 g m−2 vs 186.8 ± 26.4 g m−2), as well as the total cover of legumes (0.83 ± 0.05 vs 0.91 ± 0.03) were higher, and the proportion of bare ground (0.83 ± 0.05 vs 0.91 ± 0.03) was lower, in ungrazed plots. There were no differences in the number of plant species between treatments. Some plant species and invertebrate taxa were recorded exclusively in grazed or ungrazed plots. Invertebrate detritivores and sap sucking insects were more abundant in ungrazed plots. Ant assemblages were functionally different between treatments: Honeydew-gatherer ants were associated with ungrazed and higher plant biomass plots, and seed-eaters as well as aggressive predator ant species were associated with grazed, open habitat, plots. Management practices that maintain grazing and small scale grazing-excluded areas can increase habitat heterogeneity and promote herbaceous plant and invertebrate diversity at the local level.

The thymidine analog bromodeoxyuridine (BrdU) is incorporated into newly synthesized DNA and has been shown to increase the susceptibility of incorporating cells to ionizing radiation. However, in the absence of secondary stressors, BrdU is thought to substitute relatively benignly for thymidine and is commonly used to “birth-date” proliferative cells. We report a novel antiproliferative effect of BrdU on cancer cells, which is independent of its role in radiosensitization. A single, brief in vitro exposure to BrdU induces a profound and sustained reduction in the proliferation rate of all cancer cells examined. Cells do not die but variably up-regulate some senescence-associated proteins as they accumulate in the G1 phase of the cell cycle. Bromodeoxyuridine also impairs the proliferative capacity of primary tumor-initiating human glioma cells and may therefore represent a means of targeting cancer stem cells. Finally, conservative in vivo BrdU regimens—in the absence of any other treatment—significantly suppress the progression of gliomas in the highly aggressive, syngeneic RG2 model. These results suggest that BrdU may have an important role as an adjunctive therapeutic for a wide variety of cancers based on new insights into its effect as a negative regulator of cell cycle progression.