Enrique Hauenstein

CLASIFICACION Y CARACTERIZACION DE LA FLORA Y VEGETACION DE LOS HUMEDALES DE LA COSTA DE TOLTEN (IX REGION, CHILE)

Programas de drenado ponen en serio peligro la permanencia de los humedales de Chile. Sin embargo, la flora y vegetacion de estos ecosistemas han sido poco estudiadas. Este estudio clasifica los humedales de la costa de Tolten (IX Region, Chile), determinando su flora y vegetacion. De acuerdo a la clasificacion de la Convencion de Ramsar, se determinaron 5 tipos de humedales en el area: lagunas costeras de agua dulce, rios y arroyos permanentes, pantanos permanentes de agua dulce, pantanos estacionales de agua dulce y humedal boscoso de agua dulce (bosque pantanoso). Se trabajo con 39 censos de vegetacion de acuerdo a la metodologia fitosociologica de la Escuela Zurich-Montpellier, y recolecciones al azar. La flora vascular esta formada por 84 especies, en las que dominan las nativas (69%). En el espectro biologico dominan los hemicriptofitos, seguidos en importancia por los fanerofitos y criptofitos, estos ultimos representan a geofitos, helofitos e hidrofitos. Las especies mas importantes en el humedal son Myrceugenia exsucca, Eleocharis macrostachya, Scirpus californicus, Juncus procerus, Anagallis alternifolia y E. pachycarpa. La tabla de vegetacion ordenada muestra la presencia de 9 asociaciones vegetales: Juncetum procerii, Scirpetum californiae, Eleocharietum macrostachyaea, Loto-Cyperetum eragrostidae, Alismo-Sagittarietum montevidensis, Myriophylletum aquaticum, Myriophyllo-Potametum linguatii, Polygono-Ludwigietum peploidis y Blepharocalyo-Myrceugenietum exsuccae

Determinación del nivel de antropización de humedales como criterio para la planificación ecológica de la cuenca del lago Budi, IX Región de La Araucanía, Chile

The level of human impact on the wetlands of the Lago Budi Basin was established, as a function of the degree of alteration to the basin and the degree of alteration to the wetlands. The former was evaluated on the basis of a spatial analysis of the fragility and stability of the hydrographical basin. The latter through a modified impact model, with a panel of experts who evaluated the fulfilment of the wetlands’ function and their state. Four principal types of wetlands were recognized: estuarine, meadow, waterside and marshy. It was found that 98% of the total surface presents a high degree of alteration, as determined by its instability and fragility. Farm use was weighted as the principal agent of alteration of the wetlands’ functions, with 61% of this showing alteration in the maximum degree. This evaluation makes it possible to differentiate areas and generate base criteria for the conservation of wetlands in the basin.

Benthic macroinvertebrate assemblages as indicators of water quality applying a modified biotic index in a spatio-seasonal context in a coastal basin of Southern Chile

Se caracterizo la calidad del agua en un rio del sur de Chile a traves de un Indice Biotico, en un contexto espacio-temporal y ademas se analizo la composicion y distribucion de macroinvertebrados bentonicos y su correlacion con 14 parametros fisico-quimicos. La toma de muestras ocurrio durante un ano en 5 estaciones de muestreo en la cuenca del rio Boroa. Se registro un total de 77 taxa, los ordenes mas representativos fueron Ephemeroptera (43,30%), Diptera (24,16%) y Plecoptera (18,03%). Las especies mas abundantes fueron Meridialaris diguillina, Nousia maculata (Ephemeroptera) y Limnoperla jaffueli (Plecoptera). Acordando al IBF modificado (Indice Biotico de Familias) los resultados indicaron excelente, muy buena y buena calidad de agua, la ultima calidad fue registrada principalmente en invierno. Los parametros fisicoquimicos asi mismo indicaron calidad de agua excepcional. Estos resultados indican un bajo nivel de impacto antropogenico en la cuenca. Al aplicar el Indice Biotico de Hilsenhoff modificado basado en macroinvertebrados, la influencia de la estacionalidad sobre la calidad del agua fue evidente.

MICROPOGONIAS MANNI AS A BIOINDICATOR FOR COPPER IN LAKE BUDI (IX REGION, CHILE)

This study determined the concentration of copper in the species Micropogonias manni, a fish found in Lake Budi, which is much consumed by the population of Puerto Dominguez, IX Region of Chile. The determinations were done by atomic absorption spectrometry with flame, taking into account the sex, weight and size of the species, and, as representative samples, liver and muscle tissue. The validation of the methodology was done by using certified reference material (fish muscle), The copper concentration found in the liver fluctuated between 3,1 - 323,4 μg g-1, while for muscle tissue it was between 0,7 - 27,0 μg g -1 , dry weight. The maximum copper values found in muscle tissue, are greater than those found by other authors in various fish species. Statistical analysis showed that in muscle tissue, the sex, length and weight variables have no bearing on copper concentration; however, in the liver, the length and weight variables are significant.

Flora y vegetación de la Reserva Nacional Lago Peñuelas, Reserva de la Biósfera, Región de Valparaíso, Chile

La Reserva Nacional Lago Penuelas es una unidad del Sistema Nacional de Areas Silvestres Protegidas del Estado ubicada en la Region de Valparaiso, Chile. Esta unidad, junto al Parque Nacional La Campana, constituye una Reserva de la Biosfera. Se estudio la flora y vegetacion de esta Reserva Nacional. El estudio registro 163 especies de plantas vasculares, de las cuales 48 son nuevos registros a la documentacion previa. Al considerar los estudios y reportes realizados en el lugar, la riqueza floristica alcanza a 337 especies, de las cuales 72% es de origen nativo, distribuidas en ocho pteridofitos, dos gimnospermas, 229 dicotiledoneas y 98 monocotiledoneas, lo que representa una alta riqueza floristica. Sin embargo, la mayor proporcion de plantas aloctonas indica tambien un fuerte grado de perturbacion antropica. Catorce especies presentan problemas de conservacion (dos en peligro de extincion, 11 vulnerables y una insuficientemente conocida). La fitosociologia total del lugar reporta la presencia de 20 comunidades vegetales, de las cuales 10 son herbaceas, siete de matorral y tres arboreas; de estas, 12 ya habian sido descritas en trabajos anteriores, agregando el presente estudio ocho asociaciones nuevas para el lugar. Se propone mantener como areas restringidas de esta reserva, el sector Los Lirios, que contiene la mayor parte de las especies amenazadas, y el sector Vega del Alamo por la valiosa condicion de relicto del bosque higrofilo alli presente.

THE EFFECT OF PHYSICAL AND CHEMICAL PARAMETERS ON THE STRUCTURE AND COMPOSITION OF THE PHYTOPLANKTON COMMUNITY OF LAKE BUDI (IX REGION, CHILE)

ABSTRACTThe chemical characteristics of the waters of Lake Budi (IX Region, Chile), in winter and summer were analysed in order to establish seasonal variations and determine their influence on the various phytoplankton components. On the basis of the results it was possible to indicate that the chemical parameters found in the water body under examination vary in time and space, giving rise to different algal communities. The strong influence of salinity on the phytoplankton communities in both study periods appears to result principally from the influence of the sea, resulting from the intrusion of salt water during certain periods of the year. The predominant chemical characteristic in summer indicates a slight reduction in water quality, due to a rise in temperature and a reduction in the oxygen concentration. Keywords: Lake Budi, salinity, phytoplankton, water quality.INTRODUCTIONPhytoplankton constitutes the most important primary producer, and is a fundamental food source for consumers in many continental aquatic systems [1-2-3]. However the wide spectrum of organisms of which it is made up and the limnological characteristics which may be encountered in each individual system have hindered understanding of the processes involved in population dynamics [4]. In general, it has been established that the determining factors for the structure of phytoplankton communities in lakes result from the relationship which exists between the physical, chemical and biological parameters present in a water body [5]. Several studies carried out in freshwater environments have established that the growth of phytoplankton may be controlled to a large degree by the limitation of nutrients [6-7], the availability of light [8] and the composition and abundance of zooplankton [9]. It has also been determined that in coastal lakes which are subject to marine influence during some period of the year, salinity may also be a factor affecting the growth and distribution of phytoplankton [10-11]. The above is a consequence of the problems in osmotic regulation produced by the intrusion of sea-water, both for freshwater and marine organisms [12]. Under natural conditions, it has been determined that phytoplankton respond in a regular manner to the variations in their environment which occur in an annual cycle [13-14]. This is largely a consequence of changes to the physical characteristics and the stability of the water column. As a result, the varying algal components of the phytoplankton in a lake are a clear indicator of its environmental state. In this respect, an analysis of the composition and presence of species, their abundance and biomass, can provide the information needed to evaluate the ecological state of lacustrine systems. However, phytoplankton communities do not respond only to natural changes into the lakes, but may also present variations as a consequence of human interventions affecting the water body, either directly or through activities carried on in the basin as a whole. These influences affecting the lakes result in modifications to the structure and composition of the phytoplankton, which may take the form of changes in the taxa of which the algal associations are composed, in the abundance of each taxa, the richness and diversity of the associations, and other community parameters. Finally, due to the interdependence existing between the different organisms of which systems are composed, these variations in the phytoplankton communities translate into changes to the trophic chain and the productivity of the lakes [15]. Lake Budi constitutes a coastal lacustrine system where there is a strong marine influence due to the intrusion of salt water during certain periods of the year. Moreover, in recent decades there has been considerable human intervention in the basin. These two characteristics are indubitably determining factors in the physical and chemical conditions of the water column in the lake.As proposed, the aim of this study was to establish the physical and chemical parameters of the water which have the greatest influence, and which determine the algal associations present in the phytoplankton of Lake Budi.EXPERIMENTALArea of the study and sample collectionLake Budi (38o 52’ S; 73o 18’ W) is a coastal lake which is connected sporadically to the sea. Different bio-types may be recognized in the composition of its surroundings: banks, either covered with vegetation or bare; mud-sand beaches; and sediments with a high content of organic material derived from aquatic plants [16].Based on the special characteristics of Lake Budi and the contribution of its principal tributaries (Budi, Temo, Allipen, Comue, Bolleco and Botapulli), nine sampling stations were established: Rio Budi, Temo, Allipen, Comue, Bolleco, Botapulli, Deume 1, Deume 2 and Deume 3 (Fig. 1). To account for the marine influence present in Lake Budi, samples were taken at two times of year, the first in July 2004, representing the state of the lake in winter, and the second in January 2005, reflecting summer conditions. Two samples were taken at each sampling station: a surface sample (20cm) and a deep sample (1 m), with the exception of the Rio Budi station, where only surface samples were taken due to the shallowness of the water at the time of sampling. Chemical Analysis Eight physical and chemical parameters for water quality were established for this study: temperature, pH, salinity, oxygen in solution (OS), biochemical oxygen demand (BOD), total suspended solids (TSS), organic suspended solids (OSS) and nitrates. These were determined by extracting water samples using a Ruttner bottle, with each sample taken in duplicate. Consideration was given to conditions at sampling, the type of container, preservation and the maximum time-lapse between the taking and the analysis of the sample [17-18].e-mail: jtapia@utalca.cl

Alimentación de Micropogonias furnieri (Osteichthyes: Sciaenidae) en el lago costero Budi, Sur de Chile

The aim of this study was to determine the feeding of Micropogonias furnieri (n= 256 of commercial size over 25 cm) during austral summer and winter 2004. Du...

Morfología y dinámica dunaria en el borde costero de la Región de La Araucanía en Chile: Antecedentes para la conservación y gestión territorial

An evaluation was made of the dynamics of the dune systems of the coastal strip of the Araucania region between 1994 and 2004, based on its morphological classification and degree of stabilization as evaluated from cartographic material, aerial photographs and investigation in the field. Eight fields of dunes were defined with a total surface area of 4,597 ha being stated a total expansion of 314 ha in the period; active dunes represented 35% of the total area, while semi-stabilized and stabilized dunes represented 31% and 15% respectively. The most common type of morphology was transverse dunes and the most frequent plant species were Pinus radiata and Ammophila arenaria. Finally, the localization and the determination of the stabilization grades and dunaries shapes allow to recognize the action of the natural and anthropic factors, these integrally require to be tackle as a frame for an integrated management of this coastal zone.

Distribución de la macrofauna bentónica en el lago costero Budi, Sur de Chile

We describe the benthic macroinvertebrate associations Budi coastal lagoon southern Chile, salt nature. They relate the abundance and biomass species with or...

Effects of local land-use on riparian vegetation, water quality, and the functional organization of macroinvertebrate assemblages

Land-use change is a principal factor affecting riparian vegetation and river biodiversity. In Chile, land-use change has drastically intensified over the last decade, with native forests converted to exotic forest plantations and agricultural land. However, the effects thereof on aquatic ecosystems are not well understood. Closing this knowledge gap first requires understanding how human perturbations affect riparian and stream biota. Identified biological indicators could then be applied to determine the health of fluvial ecosystems. Therefore, this study investigated the effects of land-use change on the health of riparian and aquatic ecosystems by assessing riparian vegetation, water quality, benthic macroinvertebrate assemblages, and functional feeding groups. Twenty-one sites in catchment areas with different land-uses (i.e. pristine forests, native forests, exotic forest plantations, and agricultural land) were selected and sampled during the 2010 to 2012 dry seasons. Riparian vegetation quality was highest in pristine forests. Per the modified Macroinvertebrate Family Biotic Index for Chilean species, the best conditions existed in native forests and the worst in agricultural catchments. Water quality and macroinvertebrate assemblages significantly varied across land-use areas, with forest plantations and agricultural land having high nutrient concentrations, conductivity, suspended solids, and apparent color. Macroinvertebrate assemblage diversity was lowest for agricultural and exotic forest plantation catchments, with notable non-insect representation. Collector-gatherers were the most abundant functional feeding group, suggesting importance independent of land-use. Land-use areas showed no significant differences in functional feeding groups. In conclusion, anthropogenic land-use changes were detectable through riparian quality, water quality, and macroinvertebrate assemblages, but not through functional feeding groups. These data, particularly the riparian vegetation and macroinvertebrate assemblage parameters, could be applied towards the conservation and management of riparian ecosystems through land-use change studies.