Distribution and seasonal fluctuations in the aquatic biodiversity of the southern Altiplano

Abstract

a b s t r a c tWe compared the distribution and seasonal fluctuations in the aquatic biota in relation to chemical and physical water variables in the Altiplano watersheds of the Ascot an, Carcote and Huasco salars; Chungar a and Cotacotani lakes; Isluga and Lauca Rivers and the Parinacota wetland. We sampled during the austral autumn-winter of 2006 and in the spring-summer of 2006-2007, using three sampling stations for each system. We used canonical correspondence analysis to establish relations between frequency of taxa and environmental variables.We demonstrate that the structure and composition of the aquatic biota in humid areas of the Altiplano is determined by physical and chemical variables of the water. The most relevant one is total nitrogen, which is also the limiting nutrient for phytoplankton production in tropical systems.Benthos and zooplankton showed significant associations with the set of environmental variables (Monte Carlo test, po0.05); however, the association was not significant for phytoplankton. Lake Chungar a showed the greatest variation in composition and abundance of zooplankton between autumn-winter and spring-summer, while in the Huasco salar the physical and chemical characteristics were related to the composition and abundance of the benthonic fauna. Thus, changes in the water volume of these systems would have repercussions in chemical and physical variables, altering the species assemblage and possibly the efficiency and stability of ecosystem functions.

Culture and growth of two benthic diatoms species isolated from the Salar del Huasco (North of Chile, 20° S) at different conditions of temperature, light and nutrient

“…Studies conducted in aquatic systems of the Chilean Altiplano highlight diatoms as the most important algal group in terms of abundance, since they are more tolerant to the high salinities of these systems and, therefore, being the base of the food chain, especially as diet for waterfowl (i.e. flamingos) (Vargas et al 2004, Márquez-García et al 2009). Diatom studies conducted in Andean bodies of water in Chile are scarce (Mühlhauser et al 1995, Cruces et al 2006, Rivera & Cruces 2008), due to the difficulty of sampling, the variety of morphological and hydrological characteristics, complexity of the geological patterns of their water bodies, and the wide range of chemical and biological features for these environments.…”

“…It is likely that both the quality and the quantity of the water determine the biological diversity, its distribution and its ability to be present in this type of systems. The information on the systematics and ecology of benthic diatoms in limnic bodies of the Altiplano is scarce and mostly restricted to contributions with a strong physiographic orientation (Márquez-García et al 2009). …”

Nicho trófico de Orestias agassii (Cuvier & Valenciennes, 1846) del sistema de arroyos del salar de Huasco (20°05'S; 68°15'W)

“…Las variables físicas y químicas medidas concuerdan con lo descrito para otros sistemas límnicos de características eutrófi cas pertenecientes al altiplano sur (Márquez-García et al 2009). El aumento encontrado en la concentración de nitrógeno total durante otoño 2009 (período post lluvias) podría explicarse por la incorporación de este nutriente a causa del arrastre de material hacia el sistema de estudio por acción de las aguas lluvias provenientes del invierno altiplánico.…”

“…No obstante lo indicado en la literatura acerca de la estabilidad de estos sistemas, estudios llevados a cabo por Márquez-García et al (2009), indicarían que los cambios en la estructura comunitaria de los macroinvertebrados bentónicos y zooplancton del salar de Huasco responderían a variaciones estacionales de la composición química del sistema, y explicarían la ausencia de los taxa Hirudinea, Aeschna (Odonata) y Euchlanis (Rotifera), y el hallazgo de los taxa Alonella (Cladocera) y Hyalella (Amphipoda) en la campaña de otoño.…”

Caracterización trófica de Orestias (Teleostei: Cyprinodontidae) en el Parque Nacional Lauca

“…Estos sistemas se localizan sobre los 4000 msnm, son endorreicos, con diferencias extremas de temperatura diaria y sin interconexiones. Se caracterizan por el desarrollo de un cinturón de macrófi tas y fauna asociada similar ( Márquez et al 2009). Estudios sobre la dieta de Orestias agassii en sistemas como salares,muestra una dieta amplia (Guzman Sepúlveda 2009 ,), sin embargo, estudios sobre el tipo de dieta en la zona más alta del altiplano aún es escasa.…”