Luisa E. Delgado

The ecology of Egeria densa Planchón (Liliopsida: Alismatales): A wetland ecosystem engineer?

Egeria densa Planchon es considerada una especie invasora en los sistemas acuaticos de Chile. Su distribucion geografica original estaba limitada a regiones subtropicales de Brasil, Argentina y Uruguay. Su crecimiento rapido y su tendencia a formar densas coberturas suelen estar asociadas con el estado de aguas claras en ecosistemas acuaticos continentales de aguas someras. Su dominancia sugiere que E. densa puede comportarse como una especie ingeniera, previniendo la resuspension de sedimentos y controlando el crecimiento del fitoplancton a traves de la utilizacion de los nutrientes. Sin embargo, al mismo tiempo, como especie invasora produce efectos no deseados tales como: (1) no permitir el crecimiento de otras macrofitas nativas, (2) disminuir la diversidad en el banco de semillas, y (3) interferir con la navegacion y generacion de electricidad por turbina. Dada su importancia en el reciente (2004) cambio de estado del humedal del Rio Cruces, nos ha parecido oportuno realizar una recopilacion de articulos cientificos disponibles en la literatura sobre esta macrofita. Concluimos con una discusion sobre el rol de E. densa como especie ingeniera; a la vez que indicamos que la especie tiene ciertas vulnerabilidades y que no cumple siempre con la idea que es una especie invasora muy competitiva.

Upwelling shadows at Mejillones Bay (northern Chilean coast): a remote sensing in situ analysis

Upwelling shadows are high temperature regions within coastal upwelling systems. In this article its dynamics is described at Mejillones Bay, in the northern Chilean coast, using satellite images and in situ current data. A conceptual model relating the generation and breakdown of the shadow to the bifurcated upwelling occurring outside the bay is proposed.

Interannual Changes in the Habitat Area of the Black-Necked Swan, Cygnus melancoryphus, in the Carlos Anwandter Sanctuary, Southern Chile: A Remote Sensing Approach

Bird monitoring is frequent in wetlands; however, in the absence of information on other variables, trends in bird numbers are difficult to interpret. In this article we describe a methodology for bird’s habitat area assessment based on remote sensing. We calibrated the methodology to study the changes in the habitat area of Cygnus melancoryphus, the black-necked swan, at the Carlos Anwandter Sanctuary, a wetland located in Valdivia, Southern Chile. Swan habitat area was estimated by means of the Normalized Difference Vegetation Index (NDVI) based on Landsat images and calibrated through spectral photography by means of a portable Tetracam ADC Camera. Results show that calibrated NDVI values from Landsat images can be used to estimate habitat area but not to separate individual species of vegetation. We also show that the joint analysis of habitat area and swan count can indeed be used to separate some of the scales of variability of bird counts: those with “local-influence” associated with changes in habitat area from those of larger scales not related with habitat area.

A SPATIALLY EXPLICIT MODEL OF THE ANTARCTIC KRILL FISHERY OFF THE SOUTH SHETLAND ISLANDS

We show the development of a spatially explicit ecosystem model for the Euphausia superba fishery in the South Shetland Islands area (Antarctic Peninsula). We generated a virtual ecosystem, using a spatial automaton-geographic information system technique, to study management scenarios. We used literature data to generate the advection field, the initial krill biomass, and the distribution and size of penguin colonies in the area. Parameters for the fishing fleet were extracted from analysis of Chilean krill-fishing vessels. The model assumes that krill are passive current drifters and that penguin foraging occurs in areas close to their colonies. We analyzed the effect that a simulated 20-vessel fishing fleet would have on the availability of prey, considering the krill flux due to advection. The results show that it would be reasonable to manage the krill fishery in the South Shetland Islands as an interconnected set of ecotrophic modules, allocating the fleet down- stream from the main penguin foraging sector.

Empathy and critical thinking: primary students solving local environmental problems through outdoor learning

The present study explores the outcomes of teaching empathy and critical thinking to solve environmental problems. This investigation was done throughout the duration of an environmental education course within a primary school located in central Chile. A community-based research methodology was used to understand the formation of empathy and critical thinking. The findings reveal a significant benefit in using empathy strategies to engage students regarding the thinking processes involved with solving environmental problems. Using these elements as teaching techniques for environmental education courses can be very helpful in reaching the aims of creating a sustainable citizenry.

Using mental well-being impact assessment to understand factors influencing well-being after a disaster

The increased frequency and magnitude of natural disasters is producing a growing awareness of the need to incorporate mental well-being and resilience into policy and practice. The present research uses mental well-being impact assessment (MWIA) to identify and describe the main factors enhancing mental well-being of people affected by a tsunami on Robinson Crusoe Island in 2010, and explores their effects on peoples resilience. The main factors were: the natural environment, meaningful activities, local food, social activities, lifelong learning, transport and security. These factors influenced mental well-being through four main environmental dimensions: ecology, culture, milieu and organization. They could influence mental well-being in a constant, multiple and cumulative way. The findings of this research provide a significant practical knowledge for the improvement of MWIA practice.

Estructura del paisaje a lo largo de gradientes urbano-rurales en la cuenca del río Aisén (Región de Aisén, Chile)

Changes in landscape structure are generally associated to physical, biological and social factors. However, their integrated analysis is rarely done. The objective of this study was to determine the distribution patterns of native vegetation patches and the level of human intervention within the Aisen watershed. The main aim was to establish if the position within urban-rural gradients have some relation with the above patterns. Vegetation units were analyzed in multiple directions considering the city of Coihaique as the main urban center. Results show that the proximity to the city is not correlated with the decrease of areas covered by native vegetation, as well as with a greater level of intervention. However, we found a negative correlation between the level of intervention and the mean patch size. Furthermore, the distribution of land use/land cover patches is strongly influenced by the slope. On the other hand, considering the local socioeconomic context and the currents policies about the use of the territory and its management, it is not possible to use the urbanrural gradient concept as a paradigm that may serve as unique to study the structure of the landscape as proposed by other authors.

S-CHLOROPHYLL SQUIRTS IN THE CHILEAN COAST: A SEAWIFS PERSPECTIVE

Squirts can be defined as one-way jets, transporting coastally upwelled water to the deep ocean and terminating in a counterrotating vortex pair. These mesoscale oceanographic structures can export coastal biological production up to 200 km offshore. We describe, based on the analysis of SeaWIFS images, a squirt located in the northern Chilean coast (30° S). Our results show that the spatial structure of the velocity field, and the hammerhead shape, agree with previous conceptual models. We used the circulation data, resulting from feature-tracking analysis, to estimate the offshore export of coastal carbon production. We conclude that squirts represent a net carbon exporting mechanism accounting for 5% to 12% of coastal carbon production

Distribución del cobre en ecosistemas forestales de tipo mediterraneo

En este estudio hemos usado el metodo comparativo para analizar la distribucion de la concentracion total de cobre en los componentes de dos ecosistemas forestales, y el efecto del ingreso de cobre antropogenico. Los componentes ecosistemicos se definieron a partir de un modelo conceptual basado en la aproximacion proceso-funcional. Los componentes bioticos correspondieron a las estructuras morfologicas de los arboles; en tanto que los abioticos a los distintos horizontes del suelo. Se escogieron dos areas que difieren en cuanto a la ausencia (ecosistema de referencia) y presencia (ecosistema perturbado) de ingreso de cobre antropogenico generado por la Refineria de Ventanas-Maitencillo. Los resultados muestran que el cobre antropogenico es retenido en el material parcialmente descompuesto, y que los componentes bioticos del ecosistema perturbado presentan concentraciones de cobre por sobre los valores normales para ecosistemas forestales. Se discuten las variables controladoras del ciclo intrasistemico del cobre en ecosistemas forestales

Exploring Social-Ecological Complexities of Wetlands of International Importance (Ramsar Sites): the Carlos Anwandter Sanctuary (Valdivia, Chile) as a Case Study

Complexity is an accepted characteristic of social-ecological systems. However, its analysis has been mostly theoretical with few empirical studies. Complex systems share three features: radical openness (the system cannot be understood unless an extended, global, environment is considered), radical uncertainty (emergence and non-linearity make them impossible to be fully predictable) and contextuality (no unique way to know them). Social-ecological systems listed as important under international treaties, such as wetlands within the Ramsar Convention, share these features, which can be explored using case studies. In this article, we explore the complexities derived from the 2004 ecological change (i.e. the local collapse of an emblematic bird species) in the Carlos Anwandter Sanctuary, a Chilean coastal wetland, by means of two ten-year windows (scientific publications and Internet web pages). We based our analysis on the question: what is the state of knowledge, ten years after its ecological change? Results show many answers; science has several hypotheses with low testing possibilities. Still, civil society decided that only one (a forestry company guilty of producing the change) is valid. We discuss the role of international organizations when dealing with social-ecological conflicts and identify the conundrum that can develop in response to how these are handled.