Aldasoro J.J., de Hoyos C., Vega J.C. y Vicuña B.G.
Resumen
ABSTRACT Crustacean and macrophyte samples from 36 temporal or permanent water bodies in Gredos, Segundera and Cabrera mountains were collected. They were classified according chemical, floristic and faunistic characteristics; the ponds from Sanabria were the richest in both macrophytes and vegetation living crustacea. The ponds from Gredos had only high mountain vegetation communities and some few ubiquituous Crustacea as Daphnia longispina, Tropocyclops prasinus and Eucyclops serratulus. Little temporary waters showed higher chemical differences between different ponds, always with some diaptomid: in the less mineralized waters lives Diaptomus castaneti spp. major; and in other kind of temporary waters lives Diaptomus cyaneus.
Consultar el trabajo completo:
- Limnetica 1 Edita: Asociación Ibérica de Limnología (AIL)
Narcis Prat y María Rieradevall
Resumen
A summary of the results from the study of benthos of lakes and reservoirs in Spain is provided, with a list of the species found to date. Spanish natural lakes are smaller than European lakes; the largest is Lake Sanabria, of glacial origin, which is 3 Km long and half a kilometer wide. Many are very small and situated in the mountains; more than 200 hundred have been recorded in Spain, but only in Lake Sanabria and Lake Banyoles have the benthos been studied. Lake Sanabria is a cold oligotrophic, monomictic lake with oxygen always present in the deepest zones. Its fauna is similar to that of other central European lakes, with Micropsectra contracta (a chironomid) as the dominan1 species. Lake Banyoles is a karstic, monomictic and multibasin lake; despite the low primary productivity, due to the abundante of sulphate in the water, the allochthonous inflow of organic matter and the inflow of water from bottom springs, the profunda1 environinent is very stressing for benthic fauna. Very low oxygen concentrations and high sulphide content in the water and sediments dueto meromixis mean that only the larva of the dipteran Chaoborus flavicans was present in one of the 5 basins of the lake. In other basins, when oxygen is available (no meromixis), the fauna is similar to that of the mineralized lakes of the Aegean region and some lakes in central Italia. On the other hand, preliminary data from the Pyrenean lakes and from Sierra Nevada ponds reveal no differences with northern cold lakes.
The largest lakes in Spain are the reservoirs. There are nearly 1000 and data are available on 100 of them, including the largest. In addition to oxygen and sulphide content in the bottom waters, water level fluctuation and high sedimentation rates are disturbance factors that prevented the organization of the community. Allochthonous inputs of organic matter are also an important factor both in the reservoirs and also in the small, oligotrophic lakes like Banyoles and Sanabria. As a result the meiofaunal loop is very important in many of the Spanish water bodies . For this reason the natural lakes and reservoirs of Spain are dominated by Oligochaeta, small crustaceans and the microcarnivore chironomids (such as Procladius, Cladopelma and Microchironomus) that feed on these meoifaunal elements. The phytophagous chironomids, like Chironomus, are only abundan1 in the shallow areas of mesotrophic and eutrophic reservoirs. This situation makes it difficult to apply the typological system of SAETHER which predicts with some confidence only the benthic communities of Spanish natural lakes above 1500 m in the Pyrenees or the ponds above 2000 m in Sierra Nevada mountains. Higher temperatures (which originate a longer stratification period), the presence of sulphate in the waters of the eastern part of Spain and high inputs of sediments and allochthonous organic matter seem to be the factors that originated the differences between the benthic profundal faunas of Spanish lakes and reservoirs and those of the temperate lakes of north and central Europe.
Consultar el trabajo completo:
- Limnetica 8 Edita: Asociación Ibérica de Limnología (AIL)
Caracterización de las comunidades de odonatofauna en tramos lóticos y leníticos del complejo lacustre glaciar del lago de Sanabria y Sierra Segundera (NO de España). Diversidad y análisis biogeográfico.
Patterns of odonata assemblages in lotic and lentic systems in the Sanabria glacial lake complex in Sierra Segundera (NW Spain). Diversity and biogeographical analysis.
Javier Morales, Miguel Lizana, Ana I. Negro
Resumen
Se estudió la comunidad de odonatos en el complejo lacustre glaciar de la vertiente meridional de Sierra Segundera, desde el valle (río Tera y lago de Sanabria, 1000 m.s.n.m.) hasta las lagunas y turberas de alta montaña (>1500 m.s.n.m.). La riqueza máxima se detectó en la salida del río Tera desde el lago, mientras que en el litoral este y parte del sur del mismo no existen poblaciones de odonatos ni hábitats de reproducción y emergencia debido a las presiones turísticas sobre el litoral y la ribera. Se comprobó la reproducción de 18 taxones en el lago, incluyendo la especie amenazada Macromia splendens. Únicamente Sympetrum flaveolum, Aeshna juncea y Enallagma cyathigerum se localizaron con exclusividad en la montaña. Se capturaron adultos en vuelo entre las semanas 18 y 44 del año natural. El recambio específico entre ecosistemas es de 30 a 14, en un gradiente de 700 m desde el valle al complejo lacustre. Domina el componente biogeográfico circunmediterráneo con especies de distribución mediterráneo- occidental, franco-ibérica e ibero-magrebí, con especies eurosiberianas y de distribución holártica o paleártica; y se hallaron todas las especies de corotipo holártico conocidas en España. No se encontraron libélulas africanas migradoras en deriva meridional en ninguno de los tres veranos muestreados.
Consultar el trabajo completo:
- Bol. R. Soc. Esp. Hist. Nat., 116 Edita: Real Sociedad de Historia Natural de España (RSHN)
