Patricio Crespo

Rainfall in the Andean Páramo: New Insights from High-Resolution Monitoring in Southern Ecuador

AbstractIn mountainous regions, rainfall plays a key role in water supply for millions of people. However, rainfall data for these sites are limited and generally of low quality, making it difficult to evaluate the nature, amount, and timing of rainfall. This is particularly true for the paramo, a high-elevation grassland in the northern Andes that is a primary source of water for large populations in Ecuador, Colombia, and Venezuela. In this study, high-resolution laser disdrometer data and standard tipping-bucket rain gauge data were used to improve knowledge of rainfall in the paramo. For 36 months, rainfall was monitored in a high-elevation (3780 m MSL) headwater catchment in southern Ecuador. Average annual rainfall during this period was 1345 mm. Results indicate that (i) when input from very low–intensity events (drizzle) is taken into account, rainfall is 15% higher than previously thought; (ii) rainfall occurs throughout the year (only approximately 12% of the days are dry); (iii) rainfall occurs...

Evaluation of the Penman-Monteith (FAO 56 PM) Method for Calculating Reference Evapotranspiration Using Limited Data

Reference evapotranspiration (ETo) is often calculated using the Penman-Monteith (FAO 56 PM; Allen et al 1998) method, which requires data on temperature, relative humidity, wind speed, and solar radiation. But in high-mountain environments, such as the Andean páramo, meteorological monitoring is limited and high-quality data are scarce. Therefore, the FAO 56 PM equation can be applied only through the use of an alternative method suggested by the same authors that substitutes estimates for missing data. This study evaluated whether the FAO 56 PM method for estimating missing data can be effectively used for páramo landscapes in the high Andes of southern Ecuador. Our investigation was based on data from 2 automatic weather stations at elevations of 3780 m and 3979 m. We found that using estimated wind speed data has no major effect on calculated ETo but that if solar radiation data are estimated, ETo calculations may be erroneous by as much as 24%; if relative humidity data are estimated, the error may be as high as 14%; and if all data except temperature are estimated, errors higher than 30% may result. Our study demonstrates the importance of using high-quality meteorological data for calculating ETo in the wet páramo landscapes of southern Ecuador.

Solute behaviour and export rates in neotropical montane catchments under different land-uses

To improve our knowledge of the influence of land-use on solute behaviour and export rates in neotropical montane catchments we investigated total organic carbon (TOC), Ca, Mg, Na, K, NO3 and SO4 concentrations during April 2007-May 2008 at different flow conditions and over time in six forested and pasture-dominated headwaters (0.7-76 km²) in Ecuador. NO3 and SO4 concentrations decreased during the study period, with a continual decrease in NO3 and an abrupt decrease in February 2008 for SO4. We attribute this to changing weather regimes connected to a weakening La Nina event. Stream Na concentration decreased in all catchments, and Mg and Ca concentration decreased in all but the forested catchments during storm flow. Under all land-uses TOC increased at high flows. The differences in solute behaviour during storm flow might be attributed to largely shallow subsurface and surface flow paths in pasture streams on the one hand, and a predominant origin of storm flow from the organic layer in the forested streams on the other hand. Nutrient export rates in the forested streams were comparable to the values found in literature for tropical streams. They amounted to 68 kg/ha*y for Ca, 78 kg/ha*y for K, 45 kg/ha*y for Mg, 11-14 kg/ha*y for Na, 19-22 kg/ha*y for NO3 and 17 kg/ha*y for SO4. Our data contradict the assumption that nutrient export increases with the loss of forest cover. For NO3 we observed a positive correlation of export value and percentage forest cover.

Can Conservation Contracts Co-exist with Change? Payment for Ecosystem Services in the Context of Adaptive Decision-Making and Sustainability

This paper considers the ability of payment for ecosystem services (PES) programs to operate in the context of dynamic and complex social–ecological systems. Drawing on the experiences of two different PES programs in Latin America, we examine how PES institutions fit with the tenets of adaptive decision-making for sustainable resource management. We identify how the program goals and the connection to the market influence the incentive structure, information gathering, learning and feedback processes, and the structure of decision-making rights, specifically the ability to make and modify resource-use rules. Although limited in their generalizability, findings from the two case studies suggest a tension between the contractual model of PES and adaptive decision-making in natural resource systems. PES programs are not inherently decentralized, flexible management tools, as PES contracts tend to restrict decision-making rights and offer minimal flexibility mechanisms to change resource-use practices over the duration of the contract period. Furthermore, PES design and flexibility is heavily dependent on the goals and mission of the buyer and the respective market. If PES is to facilitate sustainable resource management, greater attention is needed to assess how the institutional design of the PES contracts influence the motivation and capacity of participants and program officers alike to adaptively manage the respective resource systems.

Temporal dynamics in dominant runoff sources and flow paths in the Andean Páramo

Funded by Central Research Office of the Universidad de Cuenca (DIUC) Secretaria de Educacion Superior, Ciencia, Tecnologia e Innovacion (SENESCYT 112–2012) . Grant Number: SENESCYT 112-2012 German Research Foundation (DFG) . Grant Number: BR2238/14-1

Quantification of rainfall interception in the high Andean tussock grasslands

El ecosistema de paramo proporciona la mayor parte del agua para las tierras altas andinas tropicales en America del Sur. Aunque la comprension de este entorno ha aumentado ultimamente, sigue habiendo una necesidad urgente de cuantificar los procesos involucrados en el ciclo hidrologico. La perdida de intercepcion (IL) es uno de los procesos menos estudiados en el paramo y, en general, en los pastizales de todo el mundo. El objetivo principal de este estudio fue cuantificar la IL a escala del evento estimandola indirectamente a partir de la precipitacion (P) y la lluvia efectiva (ER). Ademas, se evaluaron las siguientes preguntas: (a) ?Cuanto de la P se convierte en ER? (b) ?Cual es el impacto en los calculos de IL de usar un pluviometro en lugar de un disdrometro? (c) ?Que variables meteorologicas estan relacionadas con el proceso de IL? y (d) ?es posible estimar la IL a partir de variables meteorologicas? Se encontraron altos porcentajes de IL en relacion con P (10–100%). La capacidad de almacenamiento en el dosel de las gramineas es de aproximadamente 2 mm. Las observaciones del disdrometro llevaron a resultados mas precisos que las observaciones del pluviometro porque solo el disdrometro registra precipitacion ligera, precipitacion horizontal y llovizna que aumenta la cantidad de estimaciones de P, ER e IL. Tambien, encontramos que la IL esta mas fuertemente correlacionada con P; e IL se puede estimar con una regresion lineal multiple (R La capacidad de almacenamiento en el dosel de las gramineas es de aproximadamente 2 mm. Las observaciones del disdrometro llevaron a resultados mas precisos que las observaciones del pluviometro porque solo el disdrometro registra precipitacion ligera, precipitacion horizontal y llovizna que aumenta la cantidad de estimaciones de P, ER e IL. Tambien, encontramos que la IL esta mas fuertemente correlacionada con P; e IL se puede estimar con una regresion lineal multiple (R La capacidad de almacenamiento en el dosel de las gramineas es de aproximadamente 2 mm. Las observaciones del disdrometro llevaron a resultados mas precisos que las observaciones del pluviometro porque solo el disdrometro registra precipitacion ligera, precipitacion horizontal y llovizna que aumenta la cantidad de estimaciones de P, ER e IL. Tambien, encontramos que la IL esta mas fuertemente correlacionada con P; e IL se puede estimar con una regresion lineal multiple (R2 = 0.9) de P y humedad relativa para eventos donde 1.7

High-resolution hydrometeorological data from a network of headwater catchments in the tropical Andes

This article presents a hydrometeorological dataset from a network of paired instrumented catchments, obtained by participatory monitoring through a partnership of academic and non-governmental institutions. The network consists of 28 headwater catchments (<20 km2) covering three major biomes in 9 locations of the tropical Andes. The data consist of precipitation event records at 0.254 mm resolution or finer, water level and streamflow time series at 5 min intervals, data aggregations at hourly and daily scale, a set of hydrological indices derived from the daily time series, and catchment physiographic descriptors. The catchment network is designed to characterise the impacts of land-use and watershed interventions on the catchment hydrological response, with each catchment representing a typical land use and land cover practice within its location. As such, it aims to support evidence-based decision making on land management, in particular evaluating the effectiveness of catchment interventions, for which hydrometeorological data scarcity is a major bottleneck. The data will also be useful for broader research on Andean ecosystems, and their hydrology and meteorology.

Spatially distributed hydro-chemical data with temporally high-resolution is needed to adequately assess the hydrological functioning of headwater catchments

We demonstrated the great value of spatially distributed and temporally high-resolution hydro-chemical data to enhance knowledge about the intra-catchment variability of flow processes and the runoff composition of individual storms in a tropical alpine (Páramo) ecosystem. In this study, water sources (rainfall, spring water, and water from soil layers of Histosols and Andosols) and nested streams were sampled bi-weekly (2013-2014), including three storm high-resolution events (5-240 min). Water samples were analyzed for 14 tracers including electrical conductivity (EC) and rare earth trace elements and used as input to perform End-Member Mixing Analysis (EMMA). End-members identified for the outlet could explain the hydrological behavior of four out of the five tributaries, indicating similar hydro-geochemical processes and geomorphic features within the catchments. The runoff source contributions of the individual sub-catchments varied among (e.g. Andosols ~40% in tributaries and ~25% at the outlet) and within storm events (e.g. Histosols 15% higher in small peak discharge event), indicating a time-variable composition of streamflows. The latter was also reflected by the interaction of different sources and the chronology of flow paths in EMMA-space, evidencing a faster connectivity with hillslopes in the upper sub-catchments compared to the lower sub-catchments. We found counter-clockwise hysteresis patterns of storms in the lower catchments and clockwise hysteresis loops in the upper catchments. The latter bi-directionality can be related to lower slopes, wider riparian areas and the higher proportion of Histosols in the lower catchments compared to the upper sites.

Reconstruction of the mid-Holocene paleoclimate of the Ecuadorian Andean páramo at Tres Lagunas, Ecuador

Previous paleoclimate studies have suggested a warm/dry event during the mid-Holocene in páramo vegetation of the tropical Andes of South America. However, the timing of the mid-Holocene warm/dry event in Tres Lagunas, Ecuador, remains uncertain, since a previously reported bog core record characterized the warm/dry event during a hiatus in sediment deposition. In order to understand the timing of the warm/dry event in Tres Lagunas in relation to regional records, a lake sediment core was collected. Subsamples from the core were analyzed for radiocarbon dates, pollen, magnetic susceptibility, and charcoal to reconstruct the depositional, vegetational, and fire history of the area. A near-constant sedimentation rate in the lake core indicated that the lake did not dry, in contrast to the adjacent previously reported bog core. Increases in lower elevation pollen types suggest a warm period between 2700 and 2200 cal. yr BP, with the peak of warming at 2200 cal. yr BP co-occurring with the end of hiatus in the bog core record. Statistically significant increases in charcoal influx and magnetic susceptibility from 3900 to 800 cal. yr BP also suggest a dry climate during this period. While the lake record corroborates the presence of a warm/dry period in Tres Lagunas during the mid-Holocene, this record suggests a shorter period of warm/dry climate where the intensity was not sufficient to cause the lake to dry. However, anthropogenic alteration of the landscape, either vegetation or burning, must also be considered when interpreting Holocene records from this region.