No abstract

River environments are characterized by extreme spatial and temporal variation in the physical environment. The relationship of Wsh assemblages to environmental variation is poorly understood in many systems. In Chile zonation patterns of Wsh assemblages have been documented in several Andean river drainages. Coastal river drainages are comparatively small, but inordinately important because of their highly endemic Xora and fauna and their proximity to major human populations. For conservation purposes it is important to understand what environmental factors aVect assemblage structure of Wshes especially in the comparatively high diversity coastal drainages. We studied patterns of Wsh distribution and abundance in three rivers of the coastal, Andalien drainage near Concepción, Chile. We used multi-dimensional scaling analyses to compare patterns among zones (rithron, transition and potamon) and high and low Xow seasons. Species assemblages diVered by zone, but not with season. Assemblages consisted of nested subsets of species characterized by their range of distribution among zones. One species group was composed of widespread species that occurred in all three zones, another species group consisted of species found only in transitional and potamal zones, and a Wnal group was comprised of species found only in the potamal zone. The potamal zone contained the most diverse and abundant Wsh assemblage. Fish assemblages were related to both water quality and habitat E. Habit (Biodivers Conserv (2007) 16:3179-3191 1 C structure variables. This study suggests that the key to conserving the diversity of native Wsh communities in coastal Chilean rivers is in the conservation of potamal regions. Unfortunately, most protected areas in Chile are in the depauperate headwaters of drainages. Protection of only headwaters is clearly inadequate and will not contribute to the conservation of this unique freshwater Wsh fauna.

No abstract

No abstract

The Tirúa-Mocha Island area (38.2°-38.4° S) in southern Chile has been affected by two megaearthquakes in only 50 years: the 1960 Mw=9.5 Valdivia earthquake and 2010 Mw=8.8 Maule earthquake. We studied in the field the vertical ground movements occurred during the interseismic period between both earthquakes and the coseismic period of 2010 Maule earthquake and 2011 Mw=7.1 Araucanía earthquake. During the 1960 earthquake, vertical coseismic ground movements are typical of subduction related earthquakes with Mocha Island, located close to the trench, experienced bigger ground uplift (150 cm) than that occurred in Tirúa (-20 cm), place located in the continental margin at the latitude of Mocha Island. Then during the 1960-2010 interseismic period, the 1960 coseismic uplift remained at Mocha Island unlike the normal interseismic subsidence that occurred northward at Arauco Peninsula and Santa María Island. Also Tirúa experienced the biggest interseismic uplift (180 cm) in all the area affected later by 2010 Maule earthquake. Then during the 2010 Mw=8.8 Maule earthquake an anomalous vertical coseismic ground uplift occurred in the study area, opposite to that of 1960 since Mocha Island experienced lower (25 cm) ground uplift than Tirúa (90 cm). Subsequently, during the Araucanía 2011 earthquake a ground uplift in Mocha Island (50 cm) and subsidence at Tirúa (20 cm) occurred. These unexpected vertical ground movements can be explained by the existence of an upper plate splay fault located below the sea bottom between Tirúa and Mocha Island: the Tirúa-Mocha splay fault. Considering the last seismic cycle, the activity of this fault would have started after the 1960 Valdivia earthquake. During 2010 Maule earthquake, the main slip occurred at Tirúa Mocha splay fault. Finally during 2011 Araucanía earthquake, the slip occurred mainly at the updip of Wadati-Benioff plane with probable normal activity of Tirúa-Mocha splay fault. Simple elastic dislocation models considering the Wadati-Benioff plane and the Tirúa-Mocha splay fault activity, can account for all the vertical ground movements observed during 1960 earthquake, the 1960-2010 interseismic period, the 2010 Maule earthquake and the 2011 Araucanía earthquake.

RESUMENLa Región del Biobío en el centro sur de Chile es una zona de transición climática donde conviven bosques templados y esclerófi los, generando una zona de alta diversidad. Sin embargo, el área ha sido fuertemente afectada por la intervención antrópica y solo quedan algunos relictos de matorral y bosque nativo. Los geométridos, al igual que muchos insectos, están estrechamente asociados a la vegetación y por lo tanto serán afectados directamente por la intervención que se efectúe sobre esta. Así, en este estudio evaluamos los patrones de distribución y diversidad de geométridos en la Región del Biobío, con el objetivo de proponer sitios de alta prioridad para conservación mediante la identifi cación de áreas de endemismo y hot spots de diversidad. Los datos disponibles fueron procesados mediante análisis de parsimonia de endemismo y análisis de complementariedad, apoyados por SIG para rellenar vacíos y extrapolar la distribución de algunas especies de acuerdo a criterios establecidos. Encontramos una diversidad de 120 especies de geométridos, que corresponden a un 37.5 % de la diversidad nacional, distribuidas en seis áreas de endemismo, localizadas en las formaciones vegetacionales más frecuentes en la Región del Biobío: bosque altomontano de Nahuelbuta, bosque esclerófi lo de los arenales, bosque caducifolio de Concepción, bosque caducifolio andino del Biobío y bosque caducifolio de la frontera. El análisis de complementariedad determinó que 18 celdas contienen el número total de especies en la región. Basado en los análisis anteriores, se determinó que hay cinco áreas que deben ser consideradas como sitios de alta prioridad para la conservación de geométridos: (1) la ladera occidental de la Cordillera de Nahuelbuta y sector costero adyacente, (2) el área Pencopolitana de la zona litoral de la región, (3) Cerro Negro-Quillón, (4) Las Trancas, y (5) la zona del valle del Queuco-Alto Biobío.Palabras clave: análisis de complementariedad, análisis de parsimonia de endemismos, conservación de insectos, endemismo, Lepidoptera. ABSTRACTThe Biobio Region in south-central Chile is a climatic transition area where temperate and sclerophyllous forests co-occur, generating a high diversity zone. However, the area has been strongly affected by antropic intervention and only a few relicts of native forest and shrubland are left. Geometrid moths, like many other insects, are closely associated to the vegetation and therefore they will be directly affected by antropic intervention. Thus, in this study we assessed the patterns of distribution and diversity of geometrids in the Biobio Region, aiming to propose high-priority sites for conservation by identifying endemism areas and diversity hot spots. The available data were processed by parsimony analysis of endemism and complementarity analysis, helped by GIS, for to fi ll up records and to extrapolate the distribution of some species according to established criteria. We found a diversity of 120 geometrid species, corresponding to 37.5 % of the Chilean diversity, distri...

No abstract

Population increases in the coastal area in the Bío Bío region (Chile) have transformed the urban landscape, creating the need for new urban areas for residential land use. This expansion has resulted in the use of locations vulnerable to natural hazards, and outpacing urban planning instruments. The city of Coronel is a typical urban space located in this coastal zone. Coronel's Urban Planning was recently updated in 2003, and the present study's objective is to evaluate its environmental sustainability using a system of indicators applicable to the proposed land coverage model established in the 2003 urban planning instrument.Urban sustainability indicators are obtained using Geographic Information System (GIS) tools. The indicators are based on three territorial components: the distribution of land use and physical structure, land coverage and environmental quality. The data is gathered in the proposed urban land zonings. The method applies sustainability development concepts in data modeling, spatial analysis and geoprocessing in GIS. The results characterize the proposed urban model's sustainability.