RESUMO
Siete sitios fueron examinados en el sistema lótico Challhuaco-Ñireco, ubicado dentro del Parque Nacional Nahuel Huapi (PNNH), sin embargo parte de esta cuenca está urbanizada ya que atraviesa la ciudad de San Carlos de Bariloche (150,000 habitantes). Se midieron variables físico-químicas y se colectaron los macroinvertebrados bentónicos durante tres años consecutivos en siete sitios desde la cabecera hasta la desembocadura. Plecoptera, Ephemeroptera, Trichoptera y Diptera predominaron en los sitios cercanos a la cabecera, mientras que Diptera, Oligochaeta y Mollusca dominaron los sitios más bajos cercanos a la desembocadura. En relación con los grupos funcionales, los colectores-recolectores fueron los dominantes en todos los sitios y este patrón fue consistente durante los tres años de muestreo. El análisis de ordenamiento (RDA) reveló que las distribuciones de los ensambles de especies respondieron al gradiente climático y topográfico (temperatura y elevación), pero también fueron asociados con variables relacionadas al impacto antrópico (conductividad, contenido de nitratos y fosfatos). Los ensambles en cabecera estuvieron representados por insectos sensibles, mientras que los taxones tolerantes como Tubificidae, Lumbriculidae, Chironomidae y el crustáceo Aegla sp. fueron dominantes en los sitios urbanizados. En relación con las métricas analizadas, la Riqueza total, el EPT taxa, la diversidad de Shannon y el índice biótico BMPS evidenciaron diferentes niveles de disturbio en el sistema, demostrando que estas medidas son una excelente herramienta para determinar el estado de los ríos de montaña de la Patagonia.(AU)
Seven sites were examined in the Challhuaco-Ñireco system, located in the reserve of the Nahuel Huapi National Park, however part of the catchment is urbanized, being San Carlos de Bariloche (150,000 inhabitants) placed in the lower part of the basin. Physico-chemical variables were measured and benthic macroinvertebrates were collected during three consecutive years at seven sites from the headwater to the river outlet. Sites near the source of the river were characterised by Plecoptera, Ephemeroptera, Trichoptera and Diptera, whereas sites close to the river mouth were dominated by Diptera, Oligochaeta and Mollusca. Regarding functional feeding groups, collector-gatherers were dominant at all sites and this pattern was consistent among years. Ordination Analysis (RDA) revealed that species assemblages distribution responded to the climatic and topographic gradient (temperature and elevation), but also were associated with variables related to human impact (conductivity, nitrate and phosphate contents). Species assemblages at headwaters were mostly represented by sensitive insects, whereas tolerant taxa such as Tubificidae, Lumbriculidae, Chironomidae and crustacean Aegla sp. were dominant at urbanised sites. Regarding macroinvertebrate metrics employed, total richness, EPT taxa, Shannon diversity index and Biotic Monitoring Patagonian Stream index resulted fairly consistent and evidenced different levels of disturbances at the stream, meaning that this measures are suitable for evaluation of the status of Patagonian mountain streams.(AU)
Assuntos
Animais , Rios , Biota , Biodiversidade , Dípteros , Moluscos , Ephemeroptera , ArgentinaRESUMO
Siete sitios fueron examinados en el sistema lótico Challhuaco-Ñireco, ubicado dentro del Parque Nacional Nahuel Huapi (PNNH), sin embargo parte de esta cuenca está urbanizada ya que atraviesa la ciudad de San Carlos de Bariloche (150,000 habitantes). Se midieron variables físico-químicas y se colectaron los macroinvertebrados bentónicos durante tres años consecutivos en siete sitios desde la cabecera hasta la desembocadura. Plecoptera, Ephemeroptera, Trichoptera y Diptera predominaron en los sitios cercanos a la cabecera, mientras que Diptera, Oligochaeta y Mollusca dominaron los sitios más bajos cercanos a la desembocadura. En relación con los grupos funcionales, los colectores-recolectores fueron los dominantes en todos los sitios y este patrón fue consistente durante los tres años de muestreo. El análisis de ordenamiento (RDA) reveló que las distribuciones de los ensambles de especies respondieron al gradiente climático y topográfico (temperatura y elevación), pero también fueron asociados con variables relacionadas al impacto antrópico (conductividad, contenido de nitratos y fosfatos). Los ensambles en cabecera estuvieron representados por insectos sensibles, mientras que los taxones tolerantes como Tubificidae, Lumbriculidae, Chironomidae y el crustáceo Aegla sp. fueron dominantes en los sitios urbanizados. En relación con las métricas analizadas, la Riqueza total, el EPT taxa, la diversidad de Shannon y el índice biótico BMPS evidenciaron diferentes niveles de disturbio en el sistema, demostrando que estas medidas son una excelente herramienta para determinar el estado de los ríos de montaña de la Patagonia.
Seven sites were examined in the Challhuaco-Ñireco system, located in the reserve of the Nahuel Huapi National Park, however part of the catchment is urbanized, being San Carlos de Bariloche (150,000 inhabitants) placed in the lower part of the basin. Physico-chemical variables were measured and benthic macroinvertebrates were collected during three consecutive years at seven sites from the headwater to the river outlet. Sites near the source of the river were characterised by Plecoptera, Ephemeroptera, Trichoptera and Diptera, whereas sites close to the river mouth were dominated by Diptera, Oligochaeta and Mollusca. Regarding functional feeding groups, collector-gatherers were dominant at all sites and this pattern was consistent among years. Ordination Analysis (RDA) revealed that species assemblages distribution responded to the climatic and topographic gradient (temperature and elevation), but also were associated with variables related to human impact (conductivity, nitrate and phosphate contents). Species assemblages at headwaters were mostly represented by sensitive insects, whereas tolerant taxa such as Tubificidae, Lumbriculidae, Chironomidae and crustacean Aegla sp. were dominant at urbanised sites. Regarding macroinvertebrate metrics employed, total richness, EPT taxa, Shannon diversity index and Biotic Monitoring Patagonian Stream index resulted fairly consistent and evidenced different levels of disturbances at the stream, meaning that this measures are suitable for evaluation of the status of Patagonian mountain streams.
Assuntos
Animais , Biodiversidade , Biota , Rios , Argentina , Dípteros , Ephemeroptera , MoluscosRESUMO
Parapsectrocladius setosus sp. n. is described and figured as pupa and male imago, based on material collected in Patagonia, Argentina. The male of the new species groups with P. escondido Cranston & Añón Suárez by having the anal point tapering triangular; inferior volsella simple, rounded, without any dorsal ridge and apically blunt. It can be distinguished from P. escondido by the possession of strong setae on the inner margin of inferior volsella. New material of Parapsectrocladius belonging from several localities allows us to emend the generic diagnosis of the adult male, female and larva of Parapsectrocladius, discuss its phylogenetic position and to expand the geographic distribution of P. acuminatus Cranston, P. escondido and P. reissi. Cranston.
Assuntos
Chironomidae/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Argentina , Tamanho Corporal , Chironomidae/anatomia & histologia , Chironomidae/genética , Chironomidae/crescimento & desenvolvimento , Ecossistema , Feminino , Larva/anatomia & histologia , Larva/classificação , Larva/crescimento & desenvolvimento , Masculino , Tamanho do Órgão , Filogenia , Pupa/anatomia & histologia , Pupa/classificação , Pupa/crescimento & desenvolvimentoRESUMO
Three new species of Pseudosmittia Edwards from the Neotropical region, P. satheri, P. larga and P. trapezoidea, are described and figured as males. Allocladiusfortispinatus (Edwards), A. globosus Andersen et al. and A. quadrus Andersen et al. are redescribed on the basis of new material and their geographical distribution updated. A phylogenetic analysis was performed in order to assess the phylogenetic relationships of the new species. As a result, the species P. sÅtheri and P. larga are found to be sister species belonging to the angusta group. The species P. trapezoidea is the sister group of the clade ((P. propetropis (P. tropis--P. lamellata)) and belongs to the brevifurcata group sensu lato.