Diet of 0+ brown trout (Salmo trutta L., 1758) from the river Erro (Navarra, north of Spain)

The diet composition of 41 0+ brown trout (Salmo trutta L., 1758) (33-97 mm TL) captured in August 2002 in the Erro River (North of Spain) is described. The diet was mainly composed by aquatic invertebrates. Excluding nematodes because they are possible parasites, the most consumed prey items were mayflies, dipterans, and crustaceans. Fingerling brown trout refused Chironomidae, Elmidae, and terrestrial invertebrates from the drift, and Elmidae, Heptageniidae, and Leuctridae from the benthos, while they showed preference for Rhyacophilidae from the benthos. Fingerling brown trout seems to act as an opportunistic predator, and the consumption of different preys seems to be influenced by their accessibility, predation risk, and their energetic value.Se analizó la dieta de 41 alevines de trucha común (Salmo trutta L., 1758) (33-97 mm LT) del río Erro (Norte de España). Su alimentación estuvo constituida principalmente por invertebrados acuáticos. Si no se tiene en cuenta a los nematodos por la posibilidad de tratarse de parásitos, las presas más consumidas fueron efémeras, dípteros y crustáceos. Los alevines de trucha común rechazaron los quironómidos, élmidos y los invertebrados terrestres de la deriva, así como los élmidos, heptagénidos y leúctridos del bentos, mientras que mostraron preferencia por los riacofílidos del bentos. Los alevines de trucha común parecen comportarse como depredadores oportunistas, pareciendo estar el consumo de las diferentes presas influenciado por su accesibilidad, el riesgo de predación y el valor energético de cada presa

Ice cave reveals environmental forcing of long-term Pyrenean tree line dynamics

1. Tree lines are supposed to react sensitively to the current global change. However, the lack of a long-term (millennial) perspective on tree line shifts in the Pyrenees prevents understanding the underlying ecosystem dynamics and processes. 2. We combine multiproxy palaeoecological analyses (fossil pollen, spores, conifer stomata, plant macrofossils, and ordination) from an outstanding ice cave deposit located in the alpine belt c. 200 m above current tree line (Armeña-A294 Ice Cave, 2, 238 m a.s.l.), to assess for the first time in the Pyrenees, tree line dynamics, and ecosystem resilience to climate changes 5, 700–2, 200 (cal.) years ago. 3. The tree line ecotone was located at the cave altitude from 5, 700 to 4, 650 cal year bp, when vegetation consisted of open Pinus uncinata Ramond ex DC and Betula spp. Woodlands and timberline were very close to the site. Subsequently, tree line slightly raised and timberline reached the ice cave altitude, exceeding its today''s uppermost limit by c. 300–400 m during more than four centuries (4, 650 and 4, 200 cal year bp) at the end of the Holocene Thermal Maximum. After 4, 200 cal year bp, alpine tundra communities dominated by Dryas octopetala L. expanded while tree line descended, most likely as a consequence of the Neoglacial cooling. Prehistoric livestock raising likely reinforced climate cooling impacts at 3, 450–3, 250 cal year bp. Finally, a tree line ecotone developed around the cave that was on its turn replaced by alpine communities during the past 2, 000 years. 4. Synthesis. The long-term Pyrenean tree line ecotone sensitivity suggests that rising temperatures will trigger future P. uncinata and Betula expansions to higher elevations, replacing arctic–alpine plant species. Climate change is causing the rapid melting of the cave ice; rescue investigations would be urgently needed to exploit its unique ecological information

Reconstrucción de la vegetación asociada al depósito tobáceo fluvial holoceno del nogal de el batán, las parras del martín, cordillera ibérica

Development of Quaternary fluvial tufa buildings are often associated with warm and humid phases and are commonly used as climate indicators. El Nogal de El Batán Holocene fluvial tufa buildup, located in Las Parras River valley (Iberian Range, NE Spain), is investigated, following radiocarbon dating, stratigraphic description and palynological analysis. The studied deposit, 8.2 m-thick, is formed of gravels, phytoclast rudstones, calcite- coated stem boundstones and fine carbonate deposits (sands, silts and marls) with peaty horizons and carbonaceous debris. It has been dated within the upper early Holocene (ca. 8400 cal BP) and correlated with the environmental changes reconstructed for the region, identifying at least, three main phases. Pollen results highlight the existence of a conifer landscape, mainy dominated by Pinus nigra/sylvestris type and Juniperus, and locally dense riparian woodland with Corylus, Alnus, Salix, Populus, Celtis, Fraxinus, Tamarix and Rosaceae. Deciduous and evergreen oaks were the main spread regional forests accompanied by many warm-loving taxa like Pistacia, Rhamnus, Arbutus and Olea during the middle Holocene (ca. 8000-5000 cal BP). The transition towards the late Holocene (ca. 4300 cal BP) is evidenced by the rise of herbs and ruderal taxa, and especially the presence of coprophilous fungi, which are linked to the spread of agricultural and grazing practices along the river valley.El desarrollo de edificios tobáceos de origen fluvial se asocia a menudo con fases cálidas y húmedas cuaternarias y son comúnmente empleados como indicadores climáticos. En el presente trabajo se estudia el depósito tobáceo fluvial Holoceno del Nogal de El Batán, situado en el valle del río Las Parras (Cordillera Ibérica, NE España), bajo una perspectiva cronológica, estratigráfica y palinológica. La acumulación tobácea de 8,2 m de espesor, intercala gravas, facies de rudstones de fitoclastos, boundstones de tallos, limos y arenas de composición carbonatada, además de margas, lime mud y niveles turbosos. La acumulación tobácea se emplaza en el Holoceno temprano final (ca. 8400 cal BP) y se correlaciona con los cambios ambientales ocurridos en la región, identificando tres fases principales. Los análisis polínicos señalan un paisaje dominado por coníferas en la base de la secuencia, esencialmente con Pinus nigra/sylvestris tipo y Juniperus, mientras que localmente se desarrolla un bosque ripario donde destacan Corylus, Alnus, Salix, Populus, Celtis, Fraxinus, Tamarix y Rosaceae. En el Holoceno medio (ca. 8000-5000 cal BP) se produce la máxima expansión de las quercíneas, junto con taxones termófilos como Pistacia, Rhamnus, Arbutus y Olea. El incremento de taxones herbáceos y ruderales, y en especial la aparición de esporas coprófilas, marca la expansión agro-pastoril a lo largo del valle fluvial durante el Holoceno tardío (ca. 4300 cal BP)

Advantages and insights from a hierarchical Bayesian growth and dynamics model based on salmonid electrofishing removal data

Growth is a fundamental ecological process of stream-dwelling salmonids which is strongly interrelated to critical life history events (emergence, mortality, sexual maturity, smolting, spawning). The ability to accurately model growth becomes critical when making population predictions over large temporal (multi-decadal) and spatial (meso) scales, e.g., investigating the effect of global change. Body length collection by removal sampling is a widely-used practice for monitoring fish populations over such large scales. Such data can be efficiently integrated into a Hierarchical Bayesian Model (HBM) and lead to interesting findings on fish dynamics. We illustrate this approach by presenting an integrated HBM of brown trout (Salmo trutta) growth, population dynamics, and removal sampling data collection processes using large temporal and spatial scales data (20 years; 48 sites placed along a 100 km latitudinal gradient). Growth and population dynamics are modelled by ordinary differential equations with parameters bound together in a hierarchical structure. The observation process is modelled with a combination of a Poisson error, a binomial error, and a mixture of Gaussian distributions. Absolute fit is measured using posterior predictive checks, those results indicate that our model fits the data well. Results indicate that growth rate is positively correlated to catchment area. This result corroborates those of other studies (laboratory, exploratory) that identified factors besides water temperature that are related to daily ration and have a significant effect on stream-dwelling salmonid growth at a large scale. Our study also illustrates the value of integrated HBM and electrofishing removal sampling data to study in situ fish populations over large scales

Novel GMO-Based Vaccines against Tuberculosis: State of the Art and Biosafety Considerations.

&lt;p&gt;Novel efficient vaccines are needed to control tuberculosis (TB), a major cause of morbidity and mortality worldwide. Several TB vaccine candidates are currently in clinical and preclinical development. They fall into two categories, the one of candidates designed as a replacement of the Bacille Calmette Guérin (BCG) to be administered to infants and the one of sub-unit vaccines designed as booster vaccines. The latter are designed as vaccines that will be administered to individuals already vaccinated with BCG (or in the future with a BCG replacement vaccine). In this review we provide up to date information on novel tuberculosis (TB) vaccines in development focusing on the risk assessment of candidates composed of genetically modified organisms (GMO) which are currently evaluated in clinical trials. Indeed, these vaccines administered to volunteers raise biosafety concerns with respect to human health and the environment that need to be assessed and managed.&lt;/p&gt;</p

Effects of weir construction on fish population structure in the River Erro (North of Spain)

In 1996, a compound gauging weir was built in Villaveta Township (Navarra, North of Spain) in the river Erro (Ebro River Basin). Before and after its construction, fish and physical and chemical variables were examined to determine weir’s impact on the reach. Fish captured by electrofishing were measured (total length), and population density and length distribution of the species were estimated. Species diversity (Shannon’s diversity index), dominance (Simpson’s dominance index) and evenness were also calculated. The results revealed an increase in fish population density, especially in smaller specimens, but a decrease in the larger fishes. Substrate and shelter alterations could explain the observed variations in the fish community. In order to improve the consolidation of well-developed fish populations, the placement of great boulders and the restoration of the riparian vegetation are suggested

Spring diet composition of Rainbow Trout, Oncorhynchus mykiss (Walbaum, 1792) in the Urederra River (Spain)

This study describes the diet composition of 42 rainbow trout, Oncorhynchus mykiss (Walbaum, 1792) (90-480 mm TL), captured in May 1995 in the Urederra River (North of Spain). Rainbow trout of all sizes fed mainly on midge (adults, larvae and pupae), but there were some differences in the feeding habits of small and large fish. We found that as the trout grew larger terrestrial prey became the most important food item. Rainbow trout avoided Leuctridae and showed some preference for Ephemeroptera, Diptera larvae and Nemouridae larvae. Native fish predation and exploitation of the same trophic resources in the Urederra River, could negatively affect native fishes, such as European minnow, Phoxinus phoxinus L., 1758 or brown trout, Salmo trutta L., 1758