Mosquera, G.; Celleri, R.; Lazo, P.; Vaché, K.; Perakis, S. & Crespo, P. (2016): <b>Combined use of isotopic and hydrometric data to conceptualize ecohydrological processes in a high-elevation tropical ecosystem</b>. <i>Hydrological Processes</i> <b>xxx</b>, xxx.
Resource Description
Title:
Combined use of isotopic and hydrometric data to conceptualize ecohydrological processes in a high-elevation tropical ecosystem
FOR816dw ID:
1503
Publication Date:
2016-07-24
License and Usage Rights:
PAK 823-825 data user agreement. (www.tropicalmountainforest.org/dataagreementp3.do)
email:
rcelleri <at> gmail.com
Dirección de Investigación
Cuenca
Ecuador
Individual:
Patricio Lazo
Contact:
email:
webmaster <at> tropicalmountainforest.org
Individual:
Kellie Vaché
Contact:
email:
vachek <at> engr.orst.edu
Justus-Liebig-University Gießen
Institute for Landscape Ecology and Resources Management
Heinrich-Buff-Ring 26
35392 Gießen
Germany
Individual:
Steven Perakis
Contact:
email:
webmaster <at> tropicalmountainforest.org
Individual:
Patricio Crespo
Contact:
email:
pcrespos <at> yahoo.com
168 Cuenca
Ecuador
Abstract:
Few high-elevation tropical catchments worldwide are gauged, and even fewer are studied using combined hydrometric and isotopic data. Consequently, we lack information needed to understand processes governing rainfall–runoff dynamics and to predict their influence on downstream ecosystem functioning. To address this need, we present a combination of hydrometric and water stable isotopic observations in the wet Andean páramo ecosystem of the Zhurucay Ecohydrological Observatory (7.53?km2). The catchment is located in the Andes of south Ecuador between 3400 and 3900?m?a.s.l. Water samples for stable isotopic analysis were collected during 2?years (May 2011–May 2013), while rainfall and runoff measurements were continuously recorded since late 2010. The isotopic data reveal that andosol soils predominantly situated on hillslopes drain laterally to histosols (Andean páramo wetlands) mainly located at the valley bottom. Histosols, in turn, feed water to creeks and small rivers throughout the year, establishing hydrologic connectivity between wetlands and the drainage network. Runoff is primarily composed of pre-event water stored in the histosols, which is replenished by rainfall that infiltrates through the andosols. Contributions from the mineral horizon and the top of the fractured bedrock are small and only seem to influence discharge in small catchments during low flow generation (non-exceedance flows?<?Q35). Variations in source contributions are controlled by antecedent soil moisture, rainfall intensity, and duration of rainy periods. Saturated hydraulic conductivity of the soils, higher than the year-round low precipitation intensity, indicates that Hortonian overland flow rarely occurs during high-intensity precipitation events. Deep groundwater contributions to discharge seem to be minimal. These results suggest that, in this high-elevation tropical ecosystem, (1) subsurface flow is a dominant hydrological process and (2) (histosols) wetlands are the major source of stream runoff. Our study highlights that detailed isotopic characterization during short time periods provides valuable information about ecohydrological processes in regions where very few basins are gauged.
