Life history and production of the burrowing mayfly Ephoron virgo (Olivier, 1791) (Ephemeroptera: Polymitarcyidae) in the lower Ebro river: a comparison after 18 years

The life history of the burrowing mayfly Ephoron virgo (Olivier, 1791) (Ephemeroptera: Polymitarcyidae) was studied during spring and summer 2005 in the lower Ebro river (Catalonia) and compared to a previous study performed in 1987 (Ibáñez, Escosa, Muñoz and Prat 1991). The results showed an advancement of Ephoron virgo life cycle and an increase of production estimates. In 2005 larval development reached the maximum size one month earlier than in 1987, and adult emergence peak began three weeks earlier. Comparing adult sex ratios (F:M), there was a major presence of females in 2005 (1:4), while the opposite was observed in 1987 (2:1). Secondary production was higher in 2005 than in 1987, obtaining 950 mg dry weight/m²/year with the increment summation method and 1080 mg dry weight/m²/year using the removal summation method. Higher water temperatures were measured for the entire 2005 larval growth period, which were related to higher air temperatures. Therefore, that temperature increment was likely the main cause of changes observed in the Ephoron virgo life cycle.     

Long‐term effects of climatic–hydrological drivers on macroinvertebrate richness and composition in two Mediterranean streams

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Higher β‐ and γ‐diversity at species and genetic levels in headwaters than in mid‐order streams in Hydropsyche (Trichoptera)

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Cerebrospinal fluid space alterations in melancholic depression

Melancholic depression is a biologically homogeneous clinical entity in which structural brain alterations have been described. Interestingly, reports of structural alterations in melancholia include volume increases in Cerebro-Spinal Fluid (CSF) spaces. However, there are no previous reports of CSF volume alterations using automated whole-brain voxel-wise approaches, as tissue classification algorithms have been traditionally regarded as less reliable for CSF segmentation. Here we aimed to assess CSF volumetric alterations in melancholic depression and their clinical correlates by means of a novel segmentation algorithm ('new segment', as implemented in the software Statistical Parametric Mapping-SPM8), incorporating specific features that may improve CSF segmentation. A three-dimensional Magnetic Resonance Image (MRI) was obtained from seventy patients with melancholic depression and forty healthy control subjects. Although imaging data were pre-processed with the 'new segment' algorithm, in order to obtain a comparison with previous segmentation approaches, tissue segmentation was also performed with the 'unified segmentation' approach. Melancholic patients showed a CSF volume increase in the region of the left Sylvian fissure, and a CSF volume decrease in the subarachnoid spaces surrounding medial and lateral parietal cortices. Furthermore, CSF increases in the left Sylvian fissure were negatively correlated with the reduction percentage of depressive symptoms at discharge. None of these results were replicated with the 'unified segmentation' approach. By contrast, between-group differences in the left Sylvian fissure were replicated with a non-automated quantification of the CSF content of this region. Left Sylvian fissure alterations reported here are in agreement with previous findings from non-automated CSF assessments, and also with other reports of gray and white matter insular alterations in depressive samples using automated approaches. The reliable characterization of CSF alterations may help in the comprehensive characterization of brain structural abnormalities in psychiatric samples and in the development of etiopathogenic hypotheses relating to the disorders.     

Use of macroinvertebrate-based multimetric indices for water quality evaluation in Spanish Mediterranean rivers: an intercalibration approach with the IBMWP index

For the European Parliament and Commission to implement the Water Framework Directive (WFD), the water-quality indices that are currently used in Europe need to be compared and calibrated. This will facilitate the comparative assessment of ecological status throughout the European Union. According to the WFD, biologic indices should respond consistently to human impacts, using multimetric approaches and water-quality classification boundaries adjusted to a common set of normative definitions. The European Commission has started an intercalibration exercise to review biologic indices and harmonize class boundaries. We used data from rivers in Spain to compare the IBMWP (Iberian Biological Monitoring Working Party) index, which is commonly used by water authorities in Spain and by several research centers, with the Intercalibration Common Multimetric Index (ICM-Star), which was used as a standard in the intercalibration exercise. We also used data from Spanish rivers to compare the multimetric indices ICM-7 (based on quantitative data) and ICM-9 (based on qualitative data) with the IBMWP. ICM-7 and ICM-9 were proposed by the Mediterranean Geographical Intercalibration Group (Med-GIG). Additionally, we evaluated two new multimetric indices, developed specifically for macroinvertebrate communities inhabiting Mediterranean river systems. One of these is based on quantitative data (ICM-10), while the other is based on qualitative data (ICM-11a). The results show that the IBMWP index responds well to the stressor gradient present in our data, and correlates well with ICM-Star. Moreover, the IBMWP quality class boundaries were consistent with the intercalibration requirements of the WFD. However, multimetric indices showed a more linear relation with the stressor gradient in our data, and less variation in reference values. In addition, they may provide more statistical power for detecting potential environmental impacts. Multimetric indices produced similar results for quantitative and qualitative data. Thus, ICM-10 (also named IMMi-T) and ICM-11a (also named IMMi-L) indices could be used to meet European Commission requirements for assessing the water quality in Spanish Mediterranean rivers. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Handling editor: Joel Trexler     

Homage to the Virgin of Ecology,or why an aquatic insect unadapted to desiccation may maintain populations in very small,temporary Mediterranean streams

In temporary streams, the annual constriction of drying is associated with high local extinction risk. To survive in such habitats, organisms with no specific biological traits for coping with dry periods should experience high colonisation rates from permanent reaches of the same basin or from other basins. Hydropsyche siltalai is a widespread caddisfly common in permanent and temporary headwaters reaches in the Mediterranean climate region of the Iberian Peninsula. In this study, we used genetic analyses to test if populations of H. siltalai in temporary streams are resettled from populations of the same basin or from other basins. The geographical distribution of H. siltalai was surveyed in 97 temporary and permanent reaches across four basins; larvae were found in 22 reaches (12 temporary and 10 permanent). Population genetic analyses of 11 selected reaches (6 temporary and 5 permanent) revealed low genetic diversity and no genetic population structure among and within basins. Overall, H. siltalai appeared to disperse well among basins independent of stream temporality. Permanent reaches from different basins act as a source of the individuals that recolonise temporary reaches after local extinctions, indicating a metapopulation structure at regional scale. Moreover, our results support other studies that showed that dispersal among basins is a recurrent pattern in aquatic insects.     

Task-induced deactivation from rest extends beyond the default mode brain network

Activity decreases, or deactivations, of midline and parietal cortical brain regions are routinely observed in human functional neuroimaging studies that compare periods of task-based cognitive performance with passive states, such as rest. It is now widely held that such task-induced deactivations index a highly organized 'default-mode network' (DMN): a large-scale brain system whose discovery has had broad implications in the study of human brain function and behavior. In this work, we show that common task-induced deactivations from rest also occur outside of the DMN as a function of increased task demand. Fifty healthy adult subjects performed two distinct functional magnetic resonance imaging tasks that were designed to reliably map deactivations from a resting baseline. As primary findings, increases in task demand consistently modulated the regional anatomy of DMN deactivation. At high levels of task demand, robust deactivation was observed in non-DMN regions, most notably, the posterior insular cortex. Deactivation of this region was directly implicated in a performance-based analysis of experienced task difficulty. Together, these findings suggest that task-induced deactivations from rest are not limited to the DMN and extend to brain regions typically associated with integrative sensory and interoceptive processes.     

Water management in mediterranean river basins: a comparison of management frameworks, physical impacts, and ecological responses

Rivers in mediterranean climates have been extensively modified by water management infrastructure and practices, yet patterns of development and consequent effects on freshwater ecosystems have not been compared across multiple regions. To evaluate the influence of water management on mediterranean-climate rivers, we compare the historic progression of management policies, institutions, and ecosystem impacts in the Sacramento River (California, USA), Ebro River (Spain), and Biobío River (Chile) basins. There are broad similarities in patterns of ecosystem alterations related to the extensive development of dams and water management infrastructure in the three study basins. Flow regimes have been altered by the reduction of winter peak flows and increased summer baseflows. There are also common patterns of disturbance from sediment transport alteration, water quality degradation, and declines in freshwater biodiversity. Current approaches are inadequate for addressing the formidable water management challenges in California, Spain, and Chile, yet the dramatic evolution of water policies and institutions over the past 150 years suggests that further adaptation is possible. Advances toward integrated and sustainable water management models are likely to occur through incremental change, driven by growing awareness of climate change effects and public demands for water-use efficiency and improved environmental quality.     

Fire as a disturbance in mediterranean climate streams

Mediterranean climate ecosystems are among the most fire-prone in the world; however, little is known about the effects of fire on mediterranean streams (med-streams). Fire impacts on med-streams are associated with increased runoff and erosion from severely burned landscapes during storms, particularly the first intense rains. Increased inputs of water, solutes, nutrients, sediment, organic matter, and ash to streams after fires are usually observed for months to up to 4 years. Return to pre-fire conditions is associated with vegetation recovery. Benthic algae, invertebrates, and fish are reduced to low levels by scouring floods after wildfire. If riparian zones are burned, benthic algae increase, and invertebrate communities become dominated by r-strategist species. Fishes are eradicated from reaches affected by intense wildfire and often do not re-colonize quickly because of downstream barriers. In general, med-stream communities appear to be more resilient to fire compared to streams in other ecosystems because of the rapid recovery of mediterranean upland and riparian vegetation and geomorphological conditions (1–4 years in med-streams vs 5–10 years in non-med streams). However, drought or mass sediment movements after fire can prolong fire effects. Studies of the long-term effects of fire and the consequences of fire management practices are still needed.