Esse Herrera, Carlos

The Andean lakes of northern Chile and southern Bolivia are characterized by their high salinity due to arid climate and high evaporation. These lakes are poorly studied due to access difficulties. The aim of this study is to characterize two shallow saline lakes in northern Chile (Salar de Atacama, 23°S, Chile) and South Lipez of Bolivia (Khalina lake, 22.61°S) using satellite images (Landsat 8). The data involved surface temperature, chlorophyll-a concentration, and meteorological parameters (wind speed, relative humidity, atmospheric pressure). The available data revealed marked monthly variations in limnological and meteorological parameters that would be associated. The exposed antecedents revealed that the use of remote sensing techniques can be an important tool for limnological studies in zones with geographical access difficulties.

Background: Forest ecosystems provide services that are important for human use; one of the most critical ecosystem services is the provision and regulation of water. Basins with high forest improves hydrological functionality by promoting reduction in surface runoff, increase infiltration and aquifer recharge, and ensures base flow regulation amongst others. On the other hand, the conversion towards highly anthropized productive systems is usually accompanied by precarious environmental management that alters the hydrological cycle and reduction in water quality in basins. Aim: The goal of this study was to analyze land use changes and their effect on water efficiency index (WEI) in three sub-basins. Methodology: The methodology included a multi-temporal analysis of satellite images to identify land uses, also the use of SWAT (Soil and Water Assessment Tool) model for hydrological analysis in each sub-basin, information needed for calculating the WEI. Results: The results revealed the existence of no significant difference in terms of WEI between the sub-basins with predominant tree cover of native or artificial, being higher (0.89) than the WEI values reported by the sub-basin with agricultural land use (0.65). It is concluded that hydrological functions are more efficient in basins with forest cover, made up of native or exotic species, than agricultural land use with annual crop rotations. The results contribute to decision making on public policies associated to the rural productive activities. Concluded: Finally, we conclude the necessity of the promotion of forest plantation management techniques that avoid clear-cutting and multiple rotations in basin headwaters and riparian areas.

During the past three decades, various methods have been developed to improve the classification accuracy in very high resolution (< 2 m) satellite data. This study's main goal was to evaluate and select the most suitable classification approach for detecting deadwood potentially useful for energy projects that would satisfy part of the demand for heating in the area. We compare five classification approaches using a WorldView-2 (Digital Global, Ins) standard, an orthorectified image of the Aysén region of the Chilean Patagonia. The five classifiers were evaluated and selecting the best one was carried out through a confusion matrix and Kappa coefficient. The results showed that the two non-parametric classifiers used (neural net and support vector machine) offered the best performance (98%) and the best Kappa coefficient (0.97). We conclude that it is essential to promote the development of innovative projects in native forests by local owners can contribute, to the formulation of public policies that directly benefit the Aysén region's inhabitants.

Forest wetlands are biodiversity hotspots that perform functions of vital ecological importance, but they are among the world's most threatened ecosystems. Due to their high diversity of habitats and species, the study of their benthic macroinvertebrate communities is challenging, and there is no consensus on which sampling methods allow a better representation of these communities. Here we compared the performance of 3 sampling methods (hand net, corer and litterbags) in 2 temporary and 3 permanent forested wetlands in southern Chile, which were bimonthly sampled throughout a year, with 108 samples per wetland. Our results indicated that the greatest abundance and diversity were collected with the hand net, followed by the litterbags and the corer. The composition of communities collected by the hand net and litterbags were more similar between them than that of communities collected by the corer (where Chironomidae and Oligochaeta were common). We suggest that the combined use of the hand net and corer could provide a good representation of macroinvertebrate communities in forest wetlands, as they would allow recording most of the diversity, including taxa that are both sensitive and tolerant to stressors.

The tiger crab Aegla concepcionensis Schmitt, 1942 (Decapoda, Aeglidae) is a threatened freshwater decapod, endemic of Chile, with significant gaps in knowledge about its biology and ecology. The aim of this work was to contribute to the knowledge of the ecology of A. concepcionensis, through the extension of its known distribution range, recorded in a new type of ecosystem, and the description of the physicochemistry, vegetation and benthic macroinvertebrate and microalgal communities of those sites, which provides information about habitat use of the species. Our results show the presence of A. concepcionensis until 270 km south of the previously described range and reveal that the species inhabits streams and lakes. A. concepcionensis is associated to environments with cold and temperate waters, well oxygenated, with neutral pH and low conductivity, and characterized by low anthropic intervention, which is reflected in the high proportion of native riverine plant species and the high diversity of macroinvertebrate and microalgal benthic communities. We conclude that the previously restricted known distribution range of this species was mainly due to low sampling effort or misidentifications. Our results indicate that anthropic intervention should be avoided or minimized in the distribution area of A. concepcionensis, especially in those areas associated with urban expansion and touristic activities in streams and lakes.