Tesis doctoral de Tura Punti Casadella
The main objective of this thesis has been to study the structure of chironomidae assemblages in mediterranean reference streams, in order to improve our knowledge on mediterranean aquatic ecosystems. To study the state of freshwater biodiversity in reference conditions is a prerequisite for the implementation of effective management programs according to water framework directive. To achieve that, a standardized sampling protocol for macroinvertebrate studies established in guadalmed project has been identified using exclusively larvae at different special (mediterranean regions, streams and macrohabitats) and temporal scales (spring and summer). at regional scale it has been studied the chironomid community structure in three mediterranean regions around the world: south-western australia, central chile and mediterranean basin. Differences of taxonomical composition and richness were found among regions, mainly due to historical factors and also to local environmental constraint, moreover, analysis of species abundances distributions showed distinctive patterns in each region. main environmental factors that determine patterns of chironomidae communities from spanish mediterranean rivers have been analyzed. Variation in the assemblage structure of chiromomids was primarily explained by longitudinal zonation (altitude, catchment area, temperature…) Together with temporal heterogeneity (explained mainly by hydrological parameters). Furthermore, proportion of variation was calculated at different spatial scales: local, regional and geographical. We have concluded that local environmental factors explained the highest amount of variance in chironomidae community structure. Moreover, in order to study ecological requirements of chironomidae species in the study zone, optimums and tolerances to main environmental variables have been obtained for all species. Seasonal changes in the composition of chironomidae communities have been analyzed. For instance, different biological communities from siliceous headwaters have not been detected among seasons, whereas small calcareous streams have significantly different biological communities between spring and summer. finally, concordance among biological communities and fluvial ecotypes, established in spanish mediterranean according to the guidelines of water framework directive, has been analyzed. A total of five ecotypes have been defined: (1) temporary streams, (2) evaporate calcareous streams at medium altitude, ( 3) siliceous headwater streams at high altitude, (4) calcareous headwater streams at medium to high altitude and (5) large watercourses- these ecotypes have been validated with chironomidae assemblages (at the lowest taxonomical level, species or genus) and also with macroinvertebrate assemblages (at family level). Our results show that correspondence of ecotypes with biological communities (macroinvertebrates and chironomids) mismatches in some cases. For this reason, in order to establish reference communities in mediterranean streams, a classification based on biological data should be more appropriated than an environmental top-down classification.
Datos académicos de la tesis doctoral «Ecology of chironomidae communities in mediterranean reference streams«
- Título de la tesis: Ecology of chironomidae communities in mediterranean reference streams
- Autor: Tura Punti Casadella
- Universidad: Barcelona
- Fecha de lectura de la tesis: 18/01/2008
Dirección y tribunal
- Director de la tesis
- Narcis Prat Fornells
- Tribunal
- Presidente del tribunal: Francisco javier Alba tercedor
- gloria Gonzalez peña (vocal)
- Fernando Cobo gradín (vocal)
- gabriel Moya niell (vocal)