The importance of Nothofagus dombeyi (Mirb.) Oerst. riparian vegetation in the thermal regime of Andean streams of Southern Chile

Abstract

Globally, the river temperatures is a research subject, but the spatio-temporal variability of various river systems is still limited and unknown in some cases. This study aimed to compare the natural thermal regime of Andean river ecosystems with different riparian vegetation (steppe and Nothofagus dombeyi forest). The temperature of the sites was registered with a 15 min time resolution from January to July 2011. The average, maximum and daily temperature range of water showed significant differences, with lower values in the presence of N. dombeyi. Regarding the daily cycle, a slight delay was observed in the minimum temperature and an advance in the maximum temperature for the native forest site. Therefore, performing continuous monitoring using temperature sensors made it possible to determine contrasts in the thermal regime suggesting that the shade generated by the canopy reduces the solar radiation and the maximum temperature (± 4 °C) in Andean rivers. Furthermore, the conservation of forest cover of N. dombeyi in the Andean region might be important to moderate and mitigate the occurrence of higher temperatures due to global warming scenarios projected for the area.