A Computer program for estimating population size by the removal method

Es presenta un programa informàtic REMOVAL en llenguatge BASIC per a l'estimació de grandària poblacional mitjançant el mètode removal (mètode de captures successives per a poblacions tancades i esforç de mostreig constant), d'ús en un entorn VAX/VMS. El prograrna segueix el mètode de màxima versemblança, controlant les conditions d'error i les fórmules apropiades, i proporciona estimacions de grandària poblacional i capturabilitat, amb les corresponents desviacions típiques i els coeficients de variació, i dos estadístics de bondat d'ajustament amb els seus nivells de significació. S'utilitzen dades d'experiments removal per al peix ciprinodontid Aphanius iberus als aiguamolls de l'Alt Empordà per a exemplificar l'ús del programa.A BASIC computer program (REMOVAL) was developed to compute in a VAXNMS environment all the calculations of the removal method for population size estimation (catch-effort method for closed populations with constant sampling effort). The program follows the maximum likelihood methodology, checks the failure conditions, applies the appropriate formula, and displays the estimates of population size and catchability, with their standard deviations and coefficients of variation, and two goodness-of-fit statistics with their significance levels. Data of removal experiments for the cyprinodontid fish Aphanius iberus in the Alt Empordà wetlands are used to exemplify the use of the program

Tapinoma pymaeum (Dufour, 1857) (Hymenoptera, Formicidae), not a rare species

Tapinoma pygmaeum is an ant known from seven localities. Five of them are in the province of Girona (Spain). The apparent rarity and skewed distribution of this species is probably an artifact due to the confussion, in field samplings, with a similar species, Plagiolepis pygmaea.Tapinoma pygmaeum es una hormiga conocida en siete localidades. Cinco de ellas se encuentran en la provincia de Girona (España). La aparente rareza y esta distribución sesgada de las localidades puede ser un artefacte debido a que haya sido confundida, en el campo, con Plagiolepis pygmaea, similar, a primera vista, en aspecto

First record of the common bream (Abramis brama) introduced to the Iberian Peninsula

This is the first record of the common bream, Abramis brama (Linnaeus, 1758), introduced into the Iberian Peninsula. Eight individuals of this cyprinid fish species were captured (of a total of 978 fish) in the Boadella Reservoir (Catalonia, Spain) on August 18, 2004. This reservoir is only 14 km away from France, where the bream is native, and contains several exotic freshwater fish that are still not widespread in Spain. The further introduction of species and the illegal translocation of the bream by anglers to other Iberian river basins should be controlled by the Spanish administration.Se da la primera cita de la brema, Abramis brama (Linnaeus, 1758), introducida en la Península Ibérica. Se capturaron ocho individuos de esta especie de ciprínido (de un total de 978 peces) en el embalse de Boadella (Cataluña, España) el 18 de agosto de 2004. Este embalse está a sólo 14 km de Francia, donde la brema es nativa, y contiene otras especies exóticas de peces, que aún no son frecuentes en la península. La introducción ilegal de otras especies y la translocación de la brema a otras cuencas ibéricas por parte de pescadores deportivos debería ser controlada por la administración española

On the spread of the European catfish (Silurus glanis) in the Iberian Peninsula : first record in the Llobregat river basin

The first record of the European catfish (Silurus glanis L. 1758) introduced to the Llobregat river basin (NE Spain) is reported. We captured one individual of this silurid fish species (of a total of 541 fish) in La Baells reservoir on 30 August 2006. Given the low catchability of this fish species, the popularity among some anglers, and old rumours on this introduction, we hypothesize that this species has been present in the reservoir since a few years ago, despite we did not capture it in two previous surveys. The illegal introduction of this and other exotic species to other Iberian river basins should be prevented by the Spanish administration.Se da la primera cita de siluro (Silurus glanis L. 1758) introducido en la cuenca del río Llobregat (Cataluña). Se capturó un individuo de esta especie de silúrido (de un total de 534 peces) en el embalse de La Baells el 30 de agosto de 2006. Dada la baja capturabilidad de este pez, su popularidad entre algunos pescadores deportivos, y viejos rumores de esta introducción, sugerimos que esta especie está presente desde hace algunos años, a pesar que no la detectamos en dos muestreos previos. La introducción ilegal de ésta y otras especies exóticas en otras cuencas ibéricas debería ser evitada por la administración española

Multiple stressors in Mediterranean freshwater ecosystems: The Llobregat River as a paradigm

Hydrological modifications drive other ecological stressors of freshwater ecosystems and interact with them. The present paper examines the relevance of hydrological disturbances resulting from global change by presenting the case of the Llobregat River, a highly disturbed system in NE Spain. The Llobregat is a clear example of a Mediterranean river suffering from multiple stressors. Both the distribution and abundance of organisms and ecosystem functioning as a whole are greatly determined by water scarcity, water salinity, nutrient concentration, and organic (and inorganic) pollution. Structural drought exacerbates these problems, as the capacity to dilute pollutants is compromised. Controlling water abstraction and limiting nutrient and pollutant inputs downstream are essential to the structural and functional recovery of biological communities and to maximizing the ecosystem services provided by the Llobregat River. [Contrib Sci 10:161-169 (2014)