Publikationen
Es wurden 3 Publikationen gefunden
Crespo, P.; Feyen, J.; Buytaert, W.; Bücker, A.; Breuer, L.; Frede, H. & Ramirez, M. (2011): Identifying controls of the rainfall?runoff response of small catchments in the tropical Andes (Ecuador). Journal of Hydrology 407, 164?174.
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DOI: 10.1016/j.jhydrol.2011.07.021
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Abstract:
Abstract:
Tropical mountain regions are characterized by strong spatial climate gradients which together with the limited amount of data and knowledge of the underlying processes hinder the management of the water resources. Especially for regional-scale prediction it is important to identify the dominant factors controlling the rainfall?runoff response and link those to known spatial patterns of climate, soils, and vegetation. This study analyzes the rainfall?runoff relation of 13 intensively monitored micro-catchments in the Andes of southern Ecuador. The results of this study show that streamflow in the southern cordillera of the Ecuadorian Andes, above 2500 m a.s.l., primarily consists of subsurface flow. The yearly amount of streamflow is controlled by the annual rainfall depth, whereas the temporal distribution is mainly governed by the lateral saturated hydraulic conductivity, the soil water retention and the antecedent soil moisture content. Anthropogenic effects were found insignificant, with the exception in one of the studied micro-catchment. Effect of land use changes in most of the micro-catchments did not reflect in the shape of the flow duration curve because either the spatial extent of human impact was small and/or the overall basin slope was less than 20%.
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Keywords: |
Ecuador |
hydrologic response |
basin properties |
streamflow components |
principal component analysis |
andean mountain range |
Niemann, H.; Brunschön, C. & Behling, H. (2010): Vegetation/modern pollen rain relationship along an altitudinal transect between 1920 and 3185 m a.s.l. in the Podocarpus National Park region, southeastern Ecuadorian Andes. Review of Palaeobotany and and Palynology 159(1-2), 69-80.
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DOI: 10.1016/j.revpalbo.2009.11.001
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Abstract:
Abstract:
To study vegetation/modern pollen rain relationship a total of 41 pollen traps have been installed for one year on an altitudinal transect between 1800 and 3185 ma.s.l. elevation in the montane forest and páramo vegetation type of the ECSF research area, located between Loja and Zamora in the southeastern Ecuadorian Andes. Results revealed that the altitudinal vegetation gradient of lower montane forest, upper montane forest, subpáramo and páramo is well reflected in the modern pollen rain data. Principal component analysis (PCA) on the pollen rain data indicate that a high number of pollen and spore taxa are characteristic for one vegetation type or reflect the altitudinal distribution of genera and families of modern vegetation. However, a considerable number of pollen and spore taxa not representing modern vegetation types were identified as well. Wind dispersal is supposed to be responsible for differences found between plant and pollen distribution patterns. Characteristic pollen and spore taxa for the lower montane forest are Alchornea, Heliocarpus and Hyeronima; for the upper montane forest Cyathea spp., Elaphoglossum ciliatum and Purdiaea nutans; and for the subpáramo Cyperaceae, Ericaceae, Jamesonia and Valeriana. The position of the modern upper timberline in the research area is reflected in the pollen rain by an increase of subpáramo taxa and a decrease of montane forest taxa.
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Keywords: |
Ecuador |
Paramo |
Modern pollen rain |
montane forest |
upper timberline |
wind dispersal |
principal component analysis |
Bücker, A.; Crespo, P.; Frede, H.; Vaché, K.; Cisneros, F. & Breuer, L. (2010): Identifying Controls on Water Chemistry of Tropical Cloud Forest Catchments: Combining Descriptive Approaches and Multivariate Analysis. Aquatic Geochemistry 16(1), 127-149.
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DOI: 10.1007/s10498-009-9073-4
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Abstract:
Abstract:
Abstract We investigated controls on the water chemistry of a South Ecuadorian cloud
forest catchment which is partly pristine, and partly converted to extensive pasture. From
April 2007 to May 2008 water samples were taken weekly to biweekly at nine different
subcatchments, and were screened for differences in electric conductivity, pH, anion, as
well as element composition. A principal component analysis was conducted to reduce
dimensionality of the data set and define major factors explaining variation in the data.
Three main factors were isolated by a subset of 10 elements (Ca2?, Ce, Gd, K?, Mg2?,
Na?, Nd, Rb, Sr, Y), explaining around 90% of the data variation. Land-use was the major
factor controlling and changing water chemistry of the subcatchments. A second factor was
associated with the concentration of rare earth elements in water, presumably highlighting
other anthropogenic influences such as gravel excavation or road construction. Around
12% of the variation was explained by the third component, which was defined by the
occurrence of Rb and K and represents the influence of vegetation dynamics on element
accumulation and wash-out. Comparison of base- and fast flow concentrations led to the
assumption that a significant portion of soil water from around 30 cm depth contributes to
storm flow, as revealed by increased rare earth element concentrations in fast flow samples.
Our findings demonstrate the utility of multi-tracer principal component analysis to study
tropical headwater streams, and emphasize the need for effective land management in
cloud forest catchments.
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Keywords: |
Ecuador |
water quality |
land-use change |
rare earth elements |
principal component analysis |
tropical cloud forest |