Spatial scale effects on taxonomic and biological trait diversity of aquatic macroinvertebrates in Mediterranean streams

We examined the effect of spatial scale on aquatic macroinvertebrate communities in Mediterranean streams from six basins distributed across southern Europe, including Spain, France, Italy, and Greece. We classified the studied streams according to their long-term aquatic regime into the three following types: (i) permanent (P), (ii) intermittent with summer pools (I-P), and (iii) intermittent with summer dry channels (I-D). For each stream type, we analyzed taxonomic and trait diversity, as well as the composition of the macroinvertebrate community, following a spatially nested design at three spatial scales of analysis: microhabitat (substratum patches), mesohabitat (pools vs. riffles), and macrohabitat (streams). In order to assess intrinsic seasonal variability in streams from the Mediterranean region, 20 Surber samples were taken from each stream according to meso- and microhabitat frequency in the wet and the dry season during 2010. Given the need for adaptation to specific hydrological conditions and the fact that microhabitats should encompass the niche requirements of particular taxa, we hypothesized that this spatial scale would have a greater influence on macroinvertebrate taxa composition and biological traits than the other two larger spatial scales in intermittent streams. We observed that patterns in the relative importance of variance components across hierarchical spatial scales changed with time because low flow or droughts altered both mesohabitat preva - lence and microhabitat composition. Our results confirm the importance of the microhabitat scale in I-P streams in the wet season but not in the dry one, when a loss of microhabitat diversity occurred. Stream-to-stream variability was more important in P and I-D streams. Our study also explored the relationships between traits and aquatic regimes. We found that aquatic macroinvertebrates inhabiting permanent streams exhibited traits related to the longer duration of life cycles in these rivers (e.g. large size of adult stages) and adaptations to flowing conditions (e.g. modes of aquatic dispersal), whereas aquatic macroinvertebrates inhabiting intermittent streams with summer pools had traits adapted to depositional conditions and ecological preferences for confined habitats (i.e. disconnected pools without flow). Finally, aquatic macroinvertebrates from intermittent streams with summer dry channels had adaptations conferring ability to survive periods with no water (e.g. modes of aerial dispersal, resistant stages). These results indicate that microhabitat conditions should not be neglected as they can play an important role in certain situations

A biological tool to assess flow connectivity in reference temporary streams from the Mediterranean Basin

Many streams in the Mediterranean Basin have temporary flow regimes. While timing for seasonal drought is predictable, they undergo strong inter-annual variability in flow intensity. This high hydrological variability and associated ecological responses challenge the ecological status assessment of temporary streams, particularly when setting reference conditions. This study examined the effects of flow connectivity in aquatic macroinvertebrates from seven reference temporary streams across the Mediterranean Basin where hydrological variability and flow conditions are well studied. We tested for the effect of flow cessation on two streamflow indices and on community composition, and, by performing random forest and classification tree analyses we identified important biological predictors for classifying the aquatic state either as flowing or disconnected pools. Flow cessation was critical for one of the streamflow indices studied and for community composition. Macroinvertebrate families found to be important for classifying the aquatic state were Hydrophilidae, Simuliidae, Hydropsychidae, Planorbiidae, Heptageniidae and Gerridae. For biological traits, trait categories associated to feeding habits, food, locomotion and substrate relation were the most important and provided more accurate predictions compared to taxonomy. A combination of selected metrics and associated thresholds based on the most important biological predictors (i.e. Bio-AS Tool) were proposed in order to assess the aquatic state in reference temporary streams, especially in the absence of hydrological data. Although further development is needed, the tool can be of particular interest for monitoring, restoration, and conservation purposes, representing an important step towards an adequate management of temporary rivers not only in the Mediterranean Basin but also in other regions vulnerable to the effects of climate change

Ensayo de una tipología de las cuencas mediterráneas del proyecto GUADALMED siguiendo las directrices de la Directiva Marco del Agua

RESUMEN Utilizando la propuesta de tipología de ríos de la Directiva Marco del Agua en su anexo 2 se realiza un ensayo tipológico de los puntos de muestreo del proyecto GUADALMED. Según el sistema A, se presentan 16 ecotipos, lo que se juzga poco adecuado para la gestión de los mismos y sin una base ecológica que lo justifique. De acuerdo con la selección previa hecha por los miembros del grupo GUADALMED para 5 de estos ecotipos no habría estaciones de referencia. Con algunas variables medidas en los puntos de muestreo y otras de tipo geológico e hidromorfológico, se realiza un ensayo tipológico usando el sistema B. El método implica un análisis de la correlación entre variables, un cluster de las estaciones utilizando el método K-means y un análisis discriminante de cuáles son las variables que distinguen estos grupos. El estudio da como resultado la caracterización de 6 ecotipos que sin embargo, a juicio de los miembros del proyecto GUADALMED, no recogen la variedad de tipos de ríos mediterráneos. Valorando cualitativamente parámetros no introducidos (por falta de datos) en el análisis K-means, se propone una tipología provisional en 9 grupos. Un análisis de las comunidades de macroinvertebrados (a nivel taxonómico de familia) revela un grado importante de coherencia entre las familias asociadas a cada tipo y sus preferencias ecológicas conocidas. ABSTRACT A preliminary analysis was conducted of the river types in the GUADALMED project using the river typology proposed in the Water Framework Directive (WFD) in its annex 2. Using System A, 16 different types were found, a number too high for water management purposes and such typology lacks a supportive ecological basis. For 5 of these 16 ecotypes, no reference stations exist. Reference stations were selected a priori in project GUADALMED for each of the 12 basins sampled. An ecotypological analysis was performed using System B of the WFD using several variables measured during the study, and other variables obtained from maps or data bases (e.g., geology). The method included the analysis of the calibration between variables, the clustering of stations by the K-means method and a discriminant analysis. The latter revealed which factors were distinctive of each group. Six ecotypes were established for the GUADALMED study sites. These, however, do not include all the mediterranean-type streams of the region. This is mainly due to the absence in the data base of some important features of streams in the data base such as temporality or the dependence of flow on the presence of karstic aquifers, attribute

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

Las aguas superficiales de la cuenca del Río Segura (S.E. de España): caracterización fisico-química en relación al medio físico y humano /Mª del Rosario Vidal-Abarca Gutiérrez ; director Carlos Montes del Olmo, Agustín Soler Andrés

Tesis-Universidad de Murcia.Consulte la tesis en: BCA. GENERAL. ARCHIVO UNIVERSITARIO. TM 154

Which are, what is their status and what can we expect from ecosystem services provided by Spanish rivers and riparian areas?

By applying the framework proposed by Millennium Ecosystem Assessment, we analysed the current state and trends of 20 ecosystem services provided by Spanish rivers and riparian areas using 139 indicators. We compared the obtained results with the Europe and UK assessment. It is the first document that attempts to analyse the importance of services provided by Spanish rivers and riparian areas, and it forms part of the evaluation carried out for the Spanish Millennium Ecosystem Assessment. Among the provisioning services, freshwater, hydropower energy and genetic resources were classified as high importance, and water regulation and self-purification capacity, and natural hazard mitigation are among the regulating services, with landscape-aesthetic values and recreation and ecotourism featuring among the cultural services. About 61 % of the assessed ecosystem services are currently declining or degrading, but are higher than the percentage calculated for Europe (45 %) or for the UK (53 %). All regulating services are degrading, especially water regulation, natural hazard mitigation, soil formation and fertility and biological control, and the cultural services related to rural populations. Likewise, the biodiversity of Spanish aquatic ecosystems is decreasing rapidly. Land use changes and overexploitation of biological and mineral raw materials have been the main direct drivers of change in Spanish rivers and riparian zones, and relate directly to increase urbanised areas and irrigated agriculture. Finally, we draw some considerations on alternative models for aquatic ecosystems management which maintain aquatic ecosystem services and their biodiversity

Los ríos de las regiones semiáridas

En las regiones semiáridas es extraordinaria la variabilidad ambiental de los ecosistemas acuáticos. Ello se pone de manifiesto en la heterogeneidad espacial y las variaciones temporales de sus componentes físicos, químicos y bióticos. El balance hídrico negativo característico de estas regiones sitúa a sus ríos en extremos ambientales que pasan desde períodos de sequía a eventos de inundación de escasa duración. Tres factores clave determinan esta variabilidad: la temporalidad de las aguas, las interacciones del agua superficial, subsuperficial y subterránea y la tipología del sustrato. Todos ellos contribuyen a configurar el cuadro hidroquímico y su variabilidad espacial y temporal, a seleccionar los componentes biológicos y sus relaciones y a marcar las características metabólicas del ecosistema. Todas estas cuestiones deben tenerse en cuenta para la gestión de los sistemas acuáticos de regiones semiáridas.Investigación financiada por el Plan Nacional I+D+I (2000-2003), Programa Nacional de Recursos Naturales. Ref.: REN2001-0644-CO2-01/HID