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RESUMENDurante el evento extremo "El Niño", ocurrido en agosto de 2015 en la costa de la región de Tarapacá, Desierto de Atacama, se registraron precipitaciones de 50 mm en el Oasis de Niebla de Alto Patache (promedio anual de 1 mm), activando la germinación de muchas de las especies presentes en el lugar. Tras el evento antes mencionado, se demarcaron transectos y se registró la presencia y dominancia de las especies de flora; se compararon los datos florísticos con los registros históricos del sitio y con la distribución de la niebla, medida entre el 2001 y 2002. Como resultado, se identificaron 42 especies, un 78% del total de flora conocida para el área, con un registro nuevo (Tiquilia sp.). El análisis de las especies, permitió identificar tres unidades de vegetación y se observó una mayor diversidad de especies en la zona con menor altitud del farellon costero.Palabras claves: Desierto de Atacama, Alto Patache, flora, vegetación, neblina. ABSTRACTDuring the extreme precipitation event related with "El Niño", which occurred in August 2015 on the coast of the Tarapaca region, Atacama Desert, rainfall of 50 mm was recorded at the Alto Patache Fog Oasis (annual average of 1 mm), activating germination of many species present on the site. After the event, transects were demarcated and the presence and dominance of vegetation was recorded. The floristic data identified was compared with historical records and related with the distribution of fog, measured between the years 2001 and 2002. Results show 42 species identified, 78% of all known plants in the area, with one new record (Tiquilia sp.). The floristic analysis allowed the identification of three vegetation units, and a greater diversity of species was observed in lower areas of the coastal mountain chain.

Porphyry Cu-Mo deposits have influenced surface water quality in high-Andes of north-central Chile since the Miocene. Water anomalies may reduce species abundance and diversity in alpine meadows as acidic and metal-rich waters are highly toxic to plants The study assessed the importance of surface water quality on plant abundance and diversity in high-alpine meadows at the Yerba Loca Natural Santuary (YLNS), central Chile (33º15' S, 70º18' W). Hydrochemical and plant prospecting were carried out on Piedra Carvajal, Chorrillos del Plomo and La Lata meadows the growing seasons of 2006 and 2007. Direct gradient analysis was performed through canonical correspondence analysis (CCA) to look for relationships among water chemistry and plant factors. High variability in water chemistry was found inside and among meadows, particularly for pH, sulphate, electric conductivity, hardness, and total dissolved Cu, Zn, Cd, Pb and Fe. Data on species abundance and water chemical factors suggests that pH and total dissolved Cu are very important factor determining changes in plant abundance and diversity in study meadows. For instance, Festuca purpurascens, Colobanthus quitensis, and Arenaria rivularis are abundant in habitats with Cu-rich waters while Festuca magellanica, Patosia clandestina, Plantago barbata, Werneria pygmea, and Erigeron andicola are abundant in habitats with dilute waters.

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