Do mediterranean genera not included in Tachet et al. (2002) have mediterranean trait characteristics?

Do mediterranean genera not included in Tachet et al. 2002 have mediterranean trait characteristics? Multiple-trait databases are increasingly used in community ecology in different regions of the world. In Europe, Tachet et al.(2002) compiled an aquatic macroinvertebrate database for 473 taxa using information on 11 biological traits described by 63 categories. However, less studied regions, at the time of the compilation of the database, such as the mediterranean Basin, can harbour exclusive genera, which were not included in Tachet"s database. In a large-scale study across the mediterranean Basin, we found 44 genera that were not included in Tachet"s database (NEW genera). Our main aim was to compile trait information for these NEW genera and assess whether these genera had specific traits that could explain their exclusivity to the Mediterranean region. We compared the trait characteristics of NEW genera to those of genera only found in Mediterranean or temperate regions that were included in the Tachet"s database (MED and TEM genera, respectively). We found that NEW genera had more mediterranean characteristics than TEM genera and that some trait categories of NEW genera were even more mediterranean-like than the traits of MED genera (e.g., diapause). Therefore, our results suggest that the specific biological traits of these NEW genera allow them to cope successfully and exclusively with the harsh environmental conditions of the mediterranean climate rivers, which could partially explain their absence in Tachet"s database. Other explanations, such as the limited dispersal ability of these NEW genera to reach and colonize temperate Europe or the rarity of these NEW genera, should also be considered. We provide biological traits of the NEW genera to be used in future studies on the mediterranean river ecology.

Temporalidad y contaminacion como claves para interpretar la biodiversidad de macroinvertebrados en un arroyo mediterraneo (Riera de Sant Cugat, Barcelona)

En Octubre de 1995 se estudiaron 10s macroinvertebrados acuaticos en varias localidades de la cuenca de la Riera de Sant Cugat (Barcelona) situadas dentro y fuera del Parque Metropolitan0 de Collserola y, se relacionaron con la calidad y la temporalidad de las aguas. Gran parte del recorrido de 10s cauces estaba sec0 en el moment0 de estudio. Algunas localidades, situadas en 10s limites del Parque, poseian flujo permanente per0 con elevados signos de contaminacibn. Dentro del Parque se encontraron algunas zonas con caudal permanente, aunque reducido (desde menos de 1 V s hasta 32 Us), y zonas con flujo intermitente, ademas de 10s que estaban secos. En las quince localidades muestreadas se encontraron un total de 65 taxones distintos; la mayor riqueza en una sola estacidn fue de 33 y se encontraron tanto especies de zonas redfilas (simlilidos o algunos efemerdpteros) como aquellas m8s propias de aguas 16nticas como hemipteros, odonatos o algunos cole6pteros. Mediante un anhlisis de ordenacidn en el espacio se agruparon las estaciones y se ordenaron en funcibn de su flujo y del grado de polucibn, diferenciindose claramente las estaciones externas al parque (con flujo moderado y cierta contaminacidn) de aquellas situadas en el interior del parque y, entre Cstas, las de flujo permanente respecto a las encharcadas. Se analizaron las diferencias entre estos cuatro grupos segun 10s tipos de organismos existentes y su estrategia trófica. A pesar de que muchos puntos de muestreo presentaban poca agua, se refuerza la idea de la importancia de mantener 1os flujos minimos de estos rios para conservar la biodiversidad.

Quantification of environment-driven changes in epiphytic macroinvertebrate communities associated to Phragmites australis

The epiphytic macroinvertebrate communities associated with the Common Reed, Phragmites australis (Cav.) Trin. ex Steudel, were examined seasonally from summer 2004 to spring 2005 in eleven coastal lagoons of the Llobregat Delta (NE Spain) following the method proposed by Kornijów & Kairesalo (1994). The aims of the study were to: 1) characterise and quantify changes in epiphytic macroinvertebrate communities along environmental gradients; 2) assess the contribution of elements of the epiphytic compartment to structuring the community; 3) define the optima and tolerances of selected epiphytic macroinvertebrate taxa for the most relevant ecological factors responsible for assemblage composition; and 4) identify possible epiphytic species assemblages that would allow a lagoon"s typology to be established, as well as their representative indicator species. Communities showed statistically significant seasonal variation, with two faunal peaks: one in summer, with high chironomid densities, and the other in winter, with high naidid densities. These peaks showed a clear response to the influence of environmental factors. Salinity explained the highest percentage of total variance (36%), while trophic variables (nutrients, phytoplanktonic chlorophyll-a, and total organic carbon) and epiphyton biomass (19.2 and 4% of total variance explained, respectively) were secondary. Three different epiphytic macroinvertebrate species assemblages could be defined. These assemblages were directly linked to conductivity conditions, which determined the rate of survival of certain taxa, and to the existence of a direct connection with the sea, which permitted the establishment of 'brackish-water' species. In spite of the existence of these species assemblages, the species composition and biomass of epiphytic macroinvertebrates and epiphyton differed substantially between lagoons; both elements were subject to changes in the environment, which finally determined the site-to-site variation in the density and composition of the macroinvertebrate population

The Mediterranean benthic herbivores show diverse responses to extreme storm disturbances

Catastrophic storms have been observed to be one of the major elements in shaping the standing structure of marine benthic ecosystems. Yet, little is known about the effect of catastrophic storms on ecosystem processes. Specifically, herbivory is the main control mechanism of macrophyte communities in the Mediterranean, with two main key herbivores: the sea urchin Paracentrotus lividus and the fish Sarpa salpa. Consequently, the effects of extreme storm events on these two herbivores (at the population level and on their behaviour) may be critical for the functioning of the ecosystem. With the aim of filling this gap, we took advantage of two parallel studies that were conducted before, during and after an unexpected catastrophic storm event. Specifically, fish and sea urchin abundance were assessed before and after the storm in monitored fixed areas (one site for sea urchin assessment and 3 sites for fish visual transects). Additionally, we investigated the behavioural response to the disturbance of S. salpa fishes that had been tagged with acoustic transmitters. Given their low mobility, sea urchins were severely affected by the storm (ca. 50% losses) with higher losses in those patches with a higher density of sea urchins. This may be due to a limited availability of refuges within each patch. In contrast, fish abundance was not affected, as fish were able to move to protected areas (i.e. deeper) as a result of the high mobility of this species. Our results highlight that catastrophic storms differentially affect the two dominant macroherbivores of rocky macroalgal and seagrass systems due to differences in mobility and escaping strategies. This study emphasises that under catastrophic disturbances, the presence of different responses among the key herbivores of the system may be critical for the maintenance of the herbivory function.

How to introduce connectance in a frame of an expression for diversity

Systems made of parts that are totally connected do not work, neither ecosys- tems nor artifacts. Relative connectance is inversely related to diversity, and both magnitudes can find a common frame of expression, in which some constant expressing the constraints of any organization might be embodied. If S is Simp- son's index, the expression (1 - S)IS as a measure of diversity offers some advantages or, at least, helps further reasoning. Such expression is the ratio between total interspecific possible interactions and possible intraspecific inter- actions.

Riqueza y rareza de los insectos acuáticos de la laguna temporal de Espolla (Pla de l’Estany, Cataluña)

The richness and rarity of an insect community were analysed in a Mediterranean temporary pond located in NE of the Iberian Peninsula. The aquatic community was sampled weekly over 7 periods of flooding during y years (1996-1999). Distribution of rare species (with scarce presence at regional or peninsular levels, is detailed. The richness of the Espolla pond has been compared with that of other aquatic environments. The number of rare species of insects (8 taxa: 5 Corixidae, 1 Limnephilidae and 2 Chironomidae) and the insect richness (82 taxa) contrast with the traditional attribution of a low richness and rarity to the temporary aquatic environments

L'exercici físic en l'aigua durant l'embaràs i la qualitat de vida relacionada amb la salut.

Pregunta clínica: Les dones embarassades sanes de la ciutat de Lleida que, a més a més d’assistir a classes de preparació al part participen en un programa periòdic d’exercici físic en l’aigua milloraran la seva qualitat de vida relacionada amb la salut, respecte aquelles que només realitzin les classes de preparació al part? Objectiu: Verificar que l’aplicació d‘un programa d’exercici físic en l’aigua i un programa de preparació al part produeix una millora de la qualitat de vida relacionada amb la salut de les dones embarassades, que no només aplicant un programa de preparació al part on no s’efectua cap exercici físic en l’aigua de forma periòdica. Metodologia: Assaig clínic aleatori amb una mostra de 228 dones embarassades, la mostra es divideix en el grup control (n=114), que rep únicament classes de preparació al part i el grup intervenció (n=114), on a més a més de les classes de preparació al part s’efectua un programa d’exercici físic a l’aigua d’una duració de 8 setmanes. Els criteris d’inclusió són; dones embarassades sanes, de Lleida, entre els 18 i els 35 anys i que es troben entre la setmana 24 i 28 de gestació al inici de la intervenció. Els criteris d’exclusió són; les fumadores, aquelles que presentin contraindicacions a l’exercici i un IMC inferior a 20 i superior a 29. Per a l’avaluació de la qualitat de vida relacionada amb la salut s’utilitza el qüestionari SF-36 i les dades sociodemogràfiques i psicosocials.

Virus gegants desequilibren els mars

EL PRINCIPAL MOTOR DELS ECOSISTEMES MARINS són les algues unicel·lulars, que formen part de l"anomenat fitoplàncton. Incorporen el diòxid de carboni atmosfèric i el converteixen en matèria orgànica que serveix d"aliment a altres organismes del plàncton marí, el zooplàncton, i a més alliberen oxigen. En conjunt, directament o indirectament, són fonamentals per a l"alimentació de tots els organismes marins. Dins d"aquest procés, una de les qüestions importants per entendre la dinàmica dels ecosistemes marins és el reciclatge de nutrients i, més específicament, com alguns dels nutrients presents en el plàncton arriben directament al fons marí per ser reutilitzats també a grans profunditats. Un grup de recerca liderat per Assaf Vardi, del Weizmann Institute of Scienced"Israel, en col·laboració amb investigadors de la Friedrich Schiller University de Jena, a Alemanya, ha identificat el mecanisme mitjançant el qual un virus contribueix a aquest reciclatge de nutrients i, de retruc, a l"equilibri climàtic terrestre. Un virus que, tanmateix, presenta una característica molt especial: és un virus gegant.

El mercuri s'ha triplicat als nostres oceans

L"ACTIVITAT INDUSTRIAL INCLOU PROCESSOS molt diversos que sovint generen productes potencialment contaminants, que s"han estat abocant al medi ambient amb més o menys control des de l"inici de la Revolució Industrial. Alguns d"aquests productes poden ser reciclats pels mateixos cicles naturals, geoquímics i biològics, però d"altres es van acumulant, com és el cas del mercuri. Un estudi publicat a la revista Nature, encapçalat per Carl H. Lamborg, de la Woods Hole Oceanographic Institution de Massachusetts, als EUA, indica que la quantitat de mercuri als oceans s"ha triplicat des de la Revolució Industrial i, malgrat que el nivell actual encara és raonablement lluny de ser considerat tòxic per a les persones, pot començar a alterar els ecosistemes marins. A més, com assenyalen els autors del treball, la capacitat dels oceans per dissoldre el mercuri acumulat es podria estar esgotant, la qual cosa implicaria que, si no es prenen mesures que evitin els abocaments incontrolats, el seu ritme de penetració dins els ecosistemes i, a la llarga, en l"alimentació humana, podria augmentar de manera exponencial.

Influence of baffles and fish presence in the velocities distribution of a multivortex tank

Postprint (published version)

Analysis of resuspension and sedimentation processes of unaltered fish faeces using image analysis

Postprint (published version)

Aquaculture production in areas with high seasonal temperature variations: Development of planning tools

Postprint (published version)

Non aerated seaweed culture tank with rotating flow

Postprint (published version)

Longer and less overlapping food webs in anthropogenically disturbed marine ecosystems: confirmations from the past

The human exploitation of marine resources is characterised by the preferential removal of the largest species. Although this is expected to modify the structure of food webs, we have a relatively poor understanding of the potential consequences of such alteration. Here, we take advantage of a collection of ancient consumer tissues, using stable isotope analysis and SIBER to assess changes in the structure of coastal marine food webs in the South-western Atlantic through the second half of the Holocene as a result of the sequential exploitation of marine resources by hunter-gatherers, western sealers and modern fishermen. Samples were collected from shell middens and museums. Shells of both modern and archaeological intertidal herbivorous molluscs were used to reconstruct changes in the stable isotopic baseline, while modern and archaeological bones of the South American sea lion Otaria flavescens, South American fur seal Arctocephalus australis and Magellanic penguin Spheniscus magellanicus were used to analyse changes in the structure of the community of top predators. We found that ancient food webs were shorter, more redundant and more overlapping than current ones, both in northern-central Patagonia and southern Patagonia. These surprising results may be best explained by the huge impact of western sealing on pinnipeds during the fur trade period, rather than the impact of fishing on fish populations. As a consequence, the populations of pinnipeds at the end of the sealing period were likely well below the ecosystem's carrying capacity, which resulted in a release of intraspecific competition and a shift towards larger and higher trophic level prey. This in turn led to longer and less overlapping food webs.

Alimento humano : viabilidad y encaje del diseño permacultural como sistema agrícola

La Permacultura, los Paisajes de retención de agua y la Economía del bien común, se configuran como una alternativa a la situación actual de la agricultura. Mediante la combinación de estas corrientes, se puede desarrollar una agricultura más respetuosa con el entorno natural capaz de ayudar a regenerarlo. Una buena gestión del suelo fija y estabiliza el CO2 y gracias a los paisajes de captación de agua, se consigue cosechar el agua, infiltrándose en los ecosistemas y llenándolos de vida. Sumado a una correcta gestión del agua se mitigan los efectos del cambio climático en nuestras latitudes. Finalmente la economía del bien común, nos permite crear sistemas económicos más justos y sociales, encajando a la perfección con los principios de la Permacultura. Para poder aplicar dicho concepto actualmente, establecer el sistema agrícola como un sistema asociativo (asociación sin ánimo de lucro), nos permite fijar unos precios estables y sociales, dando especial importancia a la mano de obra y a la autosuficiencia.