Publications
Found 855 publication(s)
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Bachmann, S.C. (2016): Untersuchungen zur räumlichen Varianz der Isotopenverhältnisse im Holz von Cedrela montana in Bergregenwäldern Südecuadors Institute of Geography, University Erlangen-Nürnberg, bachelor thesis
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Zwar lieferten die Analysen in dieser Arbeit keine eindeutigen Antworten auf die Fra-gestellung, dennoch bietet sie Ansatzpunkte für weitere Untersuchungen zu diesem Thema. Zum einen wäre die genaue Erforschung des Reliefs vor Ort sinnvoll. Dabei könnte einerseits der Verlauf der Fließgewässer überprüft werden, andererseits könn-ten die Einzugsgebiete auf Hangrutschungen untersucht werden, welche die Boden-verhältnisse stören können. Des Weiteren kann umliegende Vegetation, die die Bäume möglicherweise beeinflussen könnte, erforscht werden.
Die aufgestellte Hypothese wird in dieser Arbeit vollständig abgelehnt, da keinerlei räumliche Muster in der topographischen Lage der Bäume erkennbar sind. Grund da-für sind vor allem eingeschränkten Möglichkeiten in ArcGIS die Topographie des Ge-bietes detailliert untersuchen zu können. Zum anderen scheint Lage der Bäume im Relief keine ausschlaggebende Ursache für deren Isotopenverhältnisse darzustellen. Sehr wahrscheinlich sind die lokalen Bodenverhältnisse entscheidend für das Isoto-pensignal der Bäume. Da die örtliche Bodenbeschaffenheit zum Teil durch Rutschkör-per gestört sein kann, ist eine Untersuchung dieser maßgeblich für zukünftige For-schungen.
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Keywords: |
Cedrela montana |
ECSF |
DEM |
hydrology |
isotopes |
dendroecology |
GIS |
mountain rainforest |
Greiner, L.; Brandl, R. & Farwig, N. (2016): Texture images as tool for predicting bird feeding guilds in a tropical montane rainforest Philipps-Universität Marburg, Department of Conservation Ecology, master thesis
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Facing the ongoing loss of natural ecosystems, worldwide monitoring of biodiversity across different spatial scales is essential for conservation planning. Remote sensing (RS) has proven to be a cost-efficient tool to access environmental characteristics such as vegetation structure and associated distributions of animal species on a broad scale. Special emphasis is put on birds as indicators for biodiversity owing to their strong species–habitat relationship. So far, bird diversity was modeled ignoring that species–habitat relationships differ among feeding guilds. This is surprising, since habitat preferences strongly depend on diet specialization. Therefore, I investigated RS texture image based vegetation metrics to test whether the predictability of specialized avian feeding guilds including insectivores, frugivores and nectarivores is higher than of the less specialized omnivore guild and overall bird diversity. I used point count data of bird communities among 30 study sites in a complex tropical mountain forest ecosystem in south-eastern Ecuador to estimate (i) Shannon index and (ii) community composition as measures of ?-diversity and combined ?- and ?-diversity, respectively. In order to relate both diversity measures to RS metrics, I compared two high dimensional predictor sets – satellite images and airborne orthophotos – with structural indices derived from a discrete return airborne Lidar sensor. Partial least squares regression was used to unveil the predictive power of all fitted feeding guild models. For the comparability of all models, a sample size correction on species number per guild was applied. Shannon index predictability ranged between 37 % and 65 %; and best predictions were achieved for insectivores using metrics from satellite or Lidar images and nectarivores species using metrics from orthophotos. Community composition was generally better predicted than Shannon index with explained variations from 65 % to 85 %. Frugivore and nectarivore community compositions were best predicted using metrics from orthophotos, whereas the two other sensors best predicted omnivores. For both diversity measures, performance of satellite derived metrics revealed slightly better model results compared to other sensors emphasizing its applicability for the regarded study area. In conclusion, specialized feeding guilds were not consistently better predicted than omnivore or overall bird diversity; rather the study showed that model performances depended on the regarded diversity measure and RS image type. However, insectivores might be the best surrogate for overall diversity with high predictability in all compared models. In addition, the high explanatory power for community composition suggests that the measure should considered in avian diversity modeling for conservation planning.
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Keywords: |
remote sensing |
bird community |
Birds |
feeding guilds |
Mattes, J.; Peter, F. & Farwig, N. (2016): Seasonal variation in nutrient use of ants in natural and disturbed montane rainforests in Southern Ecuador Philipps University of Marburg, Faculty of Biology, master thesis
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Ant assemblages are sensitive to abiotic changes in the environment, therefore they are widely used as indicators of environmental changes. Previous studies demonstrated that abiotic changes with elevation and increased anthropogenic disturbance not only reduce species richness of ant assemblages, but also modify their trophic composition and nutrient use. In tropical ecosystems where nutrient availability may vary between dry and wet seasons, seasonal or interactive effects might play an important but still neglected role in shaping these patterns. Here I used standardized bait experiments in natural and disturbed sites along an elevation gradient in a tropical montane rainforest during the wet and dry season. In order to analyze the single and interactive effects of elevation, disturbance and season on species richness, nutrient use and trophic composition of ants, I used linear mixed effect models. Additionally, I used principal component analysis (PCA) to assess whether morphological traits of ants are linked to their nutrient use. Species richness decreased monotonically along the elevation gradient, with a stronger decline in the dry season. Forest disturbance had no significant effect on species richness. The relative use of most nutrients decreased with increasing elevation. Forest disturbance only affected the relative use of lipids by decreasing it compared to natural forests. However, my results revealed complex interactive effects of elevation, disturbance and season on species richness and the use of nutrients by ant assemblages. Furthermore, I found a shift from predominantly omnivore species to more predatory species with increasing elevation. PCA revealed a preference of lipid baits by species with morphological traits associated with predatory taxa. My findings highlight the importance of seasonality and mixed effects on the composition of ant assemblages and their nutrient use in a tropical montane forest. Additionally, these results highlight the value of disturbed forests within my study area, since they support similar species richness and trophic composition of ant assemblages compared to natural forests.
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Keywords: |
Biodiversity |
ant |
elevational gradient |
trophic composition |
nutrient use |
Pérez Postigo, I.; Silva, B. & Bendix, J. (2015): Potential of Remotely Sensed Image Textures for Predicting Herbivory in the Ecuadorian Andes Fachbereich Philipps-Universität Marburg, Geographie , master thesis
Helfrich, I.H. (2015): Influence of altitude on tree structural parameters of five tree species in a tropical dry forest of Southern Ecuador Universität Göttingen, bachelor thesis
Niepoth, A.; Bendix, J. & Kümmerle, T. (2015): Remote sensing based measures of tree diversity in the Southern Ecuadorian Andes Humboldt-Universität zu Berlin, Geographisches Institut, master thesis
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The South Ecuadorian Andes are one of the hottest global hotspots of biodiversity and currently threatened by land use and climate change. Forest structure and composition are crucial factors for understanding the capacity of forest support species in changing environments. In order to prioritize limited conservation resources a better understanding of tree diversity patterns is needed. The use of image texture measures, as a proxy for spatial and forest structure has shown useful possibilities in explaining patterns of tree diversity and species richness. My goal was to evaluate the performance of different texture measures on NDVI, EVI and two broad-band combinations on high resolution (0.3m) aerial photography to predict tree diversity. Bayesian Model Averaging (BMA) was used to relate in situ measurements of tree diversity to measures of image texture. Texture explained up to 44.7% of the variability of tree diversity with measures related to habitat heterogeneity, particularly variance, providing highest explanatory power. Image texture measures bear considerable potential for predicting tree diversity in the tropics and can contribute to improvements on conservation efforts and management planning.
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Keywords: |
remote sensing |
Biodiversity conservation |
tree species richness |
tropical trees |
Windhorst, D. (2014): Prediction of hydrological fluxes under global change in a tropical mountainous rainforest ecosystem of South Ecuador University of Giessen - Institute of Landscape Ecology and Resources Management, phd thesis
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The comparatively long research history within the study area allowed to develop well-grounded hypotheses on how the hydrological system within the study area should behave (Bogner et al., 2014; Boy et al., 2008; Bücker et al., 2011, 2010; Crespo et al., 2012, 2011; Fleischbein et al., 2006; Goller et al., 2005). Based on those earlier findings made within the study area and the hydrological research conducted elsewhere in tropical mountain cloud forests (see Bonell and Bruijnzeel, 2004; Bruijnzeel, 2004; Bruijnzeel et al., 2011 for recent overviews) provided the background to shape the research conducted within this dissertation around the focal point of global change impacts on the hydrological cycle inside the study area (see chapter 1.3).Separated into three chapters, each representing a scientific research paper, this thesis will address the issue on how to evaluate effects of land-use change on the hydrological cycle (chapter 2), how stable water isotopes are distributed over space and time within the study area (chapter 3) and how stable water isotopes can be used in hydrological models to assist this analysis of global change impacts in the future (chapter 4). All of the research conducted for this dissertation was performed in the Rio San Francisco catchment within South Ecuador.
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Keywords: |
hydrologic response |
isotope tracers |
Ecuador, Climate Change, Land Use |
Hydrological modelling |
Timbe, E. (2015): Water flow dynamics assessment for a tropical montane forest basin by means of spatially differentiated multi-criteria University of Giessen - Institute of Landscape Ecology and Resources Management, phd thesis
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The present study is composed of three interlinked research papers described in three respective chapters:
Chapter 2: “Understanding uncertainties when inferring mean transit times of water trough tracer-based lumped-parameter models in Andean tropical montane cloud forest catchments” deals with the estimation of mean transit times and explores the most reliable transit time distribution functions for 32 sampled sites in the catchment, which included 18 soil water sites, 2 streamwater sites in the main river, 7 streamwater tributaries, 2 small creeks and 3 springwaters. For the analysis, seven lumped-parameters models were tested. Besides, for each simulation, uncertainties were accounted through applying the Generalized Likelihood Uncertainty Estimation approach (GLUE).
Chapter 3: “Sampling frequency trade-offs in the assessment of mean transit times of tropical montane catchment waters under semi-steady-state conditions”. This chapter describes the effect of sampling resolution data on the results provided by lumped-parameter models. Based on the insights from results described in Chapter 2, only selected models and sampled sites were screened for intercomparison. The results of this topic were aimed to account the degree of reliability of mean transit time estimations.
Chapter 4: “Multi-criteria assessment of water dynamics reveal subcatchment variability in a seemingly homogeneous montane rainforest catchment”. By considering a nested catchment approach (main river outlet and its seven tributaries), mean transit times and other diverse catchment characteristics data (e.g., hydrometric and topographic indices, physicochemical properties of stream waters) were used to perform diverse statistical and modelling techniques, such as bivariate and multivariate analysis, Principal Component Analysis (PCA), Cluster Analysis, EMMA, Hydrological and Chemical modelling. All of which allowed to gain insights on the key factors governing the flow processes in each analysed site.
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Keywords: |
hydrology |
mixing model analysis |
mean transit time |
hydrologic response |
isotope tracers |
Henz, S. (2016): Zeitreihenanalyse von Nitratkonzentrationen des Rio San Francisco in Ecuador University of Giessen - Institute of Landscape Ecology and Resources Management, master thesis
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In-Situ-Konzentrationsmessungen sind ein wichtiges Werkzeug in der Hydrologie. Die Ver-wendung entsprechender Geräte erlaubt die Aufnahme von hochfrequenten und gleichzeitig langfristigen Zeitreihen. Nitratkonzentrationen unterliegen in natürlichen Fließgewässern ta-geszeitabhängigen Schwankungen.
In dieser Arbeit werden Konzentrationsmessungen aus dem Rio San Francisco in Ecuador aus-gewertet. Ergänzt werden diese durch Wettermessungen und Pegelstandsmessungen aus dem gleichen Gebiet. Der Nitratdatensatz verläuft über etwa viereinhalb Jahre und enthält viertel-stündliche Messungen. Diese werden aufbereitet, gefiltert, und nach Tageszyklen hin unter-sucht. Zum Einsatz kommt dabei eine hierarchische Clusteranalyse mit Dynamic-Time-War-ping-Distanzen. Um Zusammenhänge der Zyklen mit den anderen Variablen aufzudecken, wird eine Lineare Diskriminanzanalyse (LDA) mit einer Variablenauswahl nach Wilks-Lambda durchgeführt. Zusätzlich werden unabhängig von Tageszyklen kurzfristige Residuen der Nit-ratkonzentration per multimodal normalverteiltem Mischungsmodell untersucht.
Die Clusteranalyse zeigt, dass es einen Cluster A mit einem regelmäßigen Tageszyklus sowie einen Cluster B mit unregelmäßigen Konzentrationsverläufen gibt. Die Trennung von A und B scheint mit der Lufttemperatur, der relativen Luftfeuchtigkeit, dem Niederschlag, und dem Pe-gel zusammen zu hängen. Ein LDA-Modell mit den Tagesvariablen Pegelamplitude, Nieder-schlagssumme, und mittlere relative Luftfeuchtigkeit ordnet erfolgreich die meisten Tage dem Cluster A zu, versagt jedoch bei der Zuordnung in Cluster B.
Die Analyse mit dem Mischungsmodell ergibt keine eindeutigen Ergebnisse. Es scheint aber einen negativen Zusammenhang zwischen den Residuen der Nitratkonzentration mit der Luft-temperatur und der Globalstrahlung zu geben.
Die Ergebnisse dieser Arbeit entsprechen teilweise jenen, welche auch in der Literatur aufzu-finden sind. Der Tagesverlauf mit einem Maximum am Morgen und einem Minimum am Abend scheint typisch für Fließgewässer zu sein. Jedoch findet sich in den Daten kein Hinweis auf eine saisonale Verschiebung des Zyklus.
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Keywords: |
hydrochemistry |
times series |
hydrological processes |
hydrologic response |
Zang, C. (2014): Snapshot Sampling von hydrochemischen Parametern in einem Ökosystem der ecuadorianischen Anden University of Giessen - Institute of Landscape Ecology and Resources Management, master thesis
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Mit Hilfe des Snapshot Samplings wurde an drei Tagen entlang des 14,2 km langen Flusses Quinoas in 50 m Abständen Wasserproben gesammelt. Das Untersuchungsgebiet liegt in den ecuadorianischen Anden (auf ca. 3.300-3.900 m) und die Hauptvegetation des EZGs ist Páramo. Alle Wasserproben wurden auf ihre Nitrat-N-, BSB- und EL-Konzentrationen untersucht. Die gemessenen Konzentrationen wurden auf ihre Korrelation zu den prozentualen Landnutzungsflächen (vor allem Páramo, Wald und Weide) der jeweiligen EZG analysiert, als Maßzahl wurde der Rangkorrelationskoeffizient nach Spearman gewählt.
Bei Nitrat-N waren im Durchschnitt die Korrelationen zu Wald und Weide am höchsten. Der starke Zusammenhang zwischen Nitrat-N und Wald konnte nicht eindeutig geklärt werden. Der Anstieg der Nitrat-N-Konzentration durch einen höheren Anteil an Weide im EZG ist vermutlich durch Düngerausbringung zu erklären. Es zeigte sich, dass Nitrat-N vermutlich vermehrt aus tieferen Bodenschichten ausgewaschen wird. Die Korrelation zwischen Nitrat-N und Páramo ist mittelmäßig stark und negativ. Nährstoffe in diesen Böden liegen oft stark gebunden oder in Pflanzen gespeichert vor und können nur schwer ausgewaschen werden.
Aus den Waldflächen des EZG wird relativ gesehen wenig BSB ausgewaschen. In den Wäldern wird nur nach Perioden mit vielen Niederschlägen etwas organische Materie in den Fluss geschwemmt. Der Großteil der organischen Materie der Páramoböden liegt gebunden vor und daher ist der Zusammenhang zwischen BSB und Páramo zwar positiv, aber nicht besonders stark. Die Korrelationen zwischen BSB und Weide sind im Durchschnitt negativ. Die Weideflächen im EZG werden nur extensiv bewirtschaftet und die Tieranzahl ist sehr gering. Im Gegensatz zu den anderen Parametern zeigten sich bei BSB basierend auf verschiedene Wetterverhältnisse sehr unterschiedliche Ergebnisse zwischen den drei Messterminen.
Wie bei Nitrat-N ist die Korrelation zwischen EL und Páramo negativ und zwischen EL und Wald, sowie Weide positiv. Bei EL sind die Spearmans Rangkorrelationskoeffizienten im Allgemeinen sehr hoch. Allerdings kann hier nicht ausgeschlossen werden, dass eigentlich andere Faktoren (wie Geologie oder Bodentyp) vorrangig entscheidend sind.
Einflüsse von Forellenfarmen konnten basierend auf den Ergebnissen dieser Arbeit nicht gefunden werden. Einige große Zuflüsse können einen Teil der Parameterkonzentrationsschwankungen im Flussverlauf erklären. Ob die Parameterkonzentrationen der Zuflüsse sich auf Grund ihrer Landnutzung vom Hauptfluss unterscheiden konnte nicht eindeutig geklärt werden.
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Keywords: |
hydrochemistry |
land-use change |
nutrient export |
Schob, S. (2014): Concentration-Discharge Hysteresis Effects of BOD, COD, Nitrate and Turbidity during Storm Flow Events in the Paramo of Southern Ecuador University of Giessen - Institute of Landscape Ecology and Resources Management, bachelor thesis
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Future climate and land use change may have a great impact on essential ecosystem functions such as carbon storage and water supply of the Andean p´aramo ecosystem. As hydrogeochemical processes in the p´aramo and possible reactions to these changes are still largely unknown, nutrient fluxes during storm flow events in a
p´aramo catchment in the Cajas National Park of south Ecuador were studied. From February to June 2014, discharge and stream concentrations of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity and nitrate (NO3-N) were monitored in five minute intervals in the Quinuas River. In order to study the catchment’s response to rainfall events, rotational patterns of concentration-discharge hysteresis effects were analysed. In total, 35 events were suitable for analysing hysteresis effects of BOD, COD, and turbidity. Nitrate concentrations were studied in 20 events. Precipitation events led to an increase of concentration of all parameters. Hysteresis patterns showed a high consistency. COD, turbidity, and nitrate rotated mainly clockwise, BOD counterclockwise. Therefore, a fast response of the sources of COD, nitrate, and turbidity is suggested. This might be mainly due to a fast subsurface flow through the upper organic soil horizons. BOD sources, mainly soil surface and litter layer, predominate later in the
storm flow event
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Keywords: |
hydrochemistry |
hydrological processes |
nutrient cycle |
indirect land use change (ILUC) |
Gietmann, L. (2016): Identifikation und Analyse lokaler und saisonaler Einflussfaktoren auf die Nährstofffrachten eines ecuadorianischen Hochgebirgsökosystems University of Giessen - Institute of Landscape Ecology and Resources Management , bachelor thesis
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This report examines the impact of climate changes and variations in land use based on water samples taken from the alpine grassland ecosystem Páramo in the South of Ecuador. For this purpose, two monitoring points were identified, which hold a different level of anthropogenic influences. Predominantly, the Virgin area exists of natural Páramo. In contrast, the area of Chirimachay is by far more versatile since its components are natural Páramo, nature forest, livestock as well as trout farming.
In order to analyse the climate in a diurnal and seasonal cycle, date of temperature and precip-itation has been evaluated. For the purpose of this report, fluxes of nitrogen-nitrate (N-NO3), chemical and biochemical oxygen demand (COD / BOD) and turbidity were analysed. In order to examine the fluxes, concentrations of the mentioned parameters were measured in a five minutes routine in the first step. Afterwards, they were multiplied with current discharge data.
Analysis of the data does not illustrate a correlation between nutrient fluxes and air temperature. In terms of precipitation, however, it was possible to identify a relation to COB and BOD (given R=0,829 each in Chirimachay area) by using a linear correlation matrix. Additionally, in the Chirimachay area, evidence for a relation between precipitation and turbidity was found. Even though there is no linear correlation between N-NO3 and precipitation, it is still possible that there is another relation based on the characteristics of moving in soil during different environ-mental conditions.
Furthermore, land use has different effects on each parameter. By using scatter plots and statis-tical tests it was possible to analyse the extent of differences in fluxes due to the specific land use. Therefore, N-NO3 fluxes are not influenced while COD, BOD, and on a minor scale, tur-bidity, are correlating to each other.
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Keywords: |
N-cycle |
hydrology |
seasonality |
nutrient export |
Bogner, F.; Bendix, J. & Beck, E. 2016: Biodiversity Hotspot - Tropical Mountain Rainforest. (NCI Foundation, Ecuador).
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DOI: 10.5678/lcrs/pak823-825.cit.1513
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In 2008, a booklet “The Mountain Rainforest: Scientific Discoveries in a Highly Diverse Eco - system in Southern Ecuador” was published by a German Research Unit, informing the public about 10 years of biodiversity and ecosystem research in the Eastern range of the tropical Andes of Ecuador. The authors (K. Kiss & A. Bräuning) had compiled 14 contributions on diversity, dynamic processes and potential use of the primary forest and of its agricultural replacement systems. Another 8 years of research in the area have immensely widened the understanding of the ecosystem and its value for science in general and for the region in particular. The new book “Biodiversity Hotspot: Tropical Mountain Rainforest”, starting with an introductory chapter on the research area as the second hottest biodiversity hotspot worldwide, presents in an apprehensible way the major results of 16 collaborative projects addressing questions of basic as well as applied research. Understanding ecosystem components and processes is the prerequisite for an assessment of its stability under climate and land use changes. With this book the authors acknowledge the long-standing support of the work by the German Research Foundation and by the foundation Naturaleza y Cultura Internacional in Loja and San Diego, as well as the fruitful collaboration with our Ecuadorian partners, the Universidad Tecnica Particular de Loja, the Universidad Nacional de Loja, the Universidad de Cuenca and the Universidad de Azuay, and the local weather service INAMHI. We also appreciate very much the important contributions of our non-university research partners beyond NCI, ETAPA EP (Empresa Pública Municipal de Telecomunicaciones, Agua potable, lcantarillado y Saneamiento de Cuenca - Ecuador), Gobierno Municipal de Zamora and the regional water fund FORAGUA (Fondo Regional del Agua).
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Keywords: |
Ecuador |
biodiversity hotspots |
Bendix, J. & Beck, E. (2016): Environmental Change And Its Impacts In A Biodiversity Hotspot Of The South Ecuadorian Andes–Monitoring And Mitigation Strategies. Erdkunde 70(1), 1-4.
DFG PAK 823-825 (2016): Tabebuia Bulletin, Issue 5. Laboratory for Climatology and Remote Sensing (LCRS), University of Marburg, Marburg, Germany.
Rollenbeck, R.; Trachte, K. & Bendix, J. (2016): A New Class of Quality Controls for Micrometeorological Data in Complex Tropical Environments. Journal of Atmospheric and Oceanic Technology 33(1), 169-183.
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DOI: 10.1175/JTECH-D-15-0062.1
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Quality control is a particularly demanding problem for micrometeorological studies in complex environments. With the transition to electronic sensing and storage of climate data in high temporal resolution,
traditional approaches of homogenization are insufficient for addressing the small-scale variability and spatial
heterogeneity of the data. This problem can be successfully addressed by introducing a new class of control
procedures based on the physical and climatological relations between different climate variables. The new
approach utilizes knowledge about the interdependency of air temperature, precipitation, radiation, relative
air humidity, cloud cover, and visibility to develop empirical functions for determining the probability
margins for the co-occurrence of specific conditions in tropical mountains and deserts. It can also be applied to
other geographic settings by adjusting the parameters derived from the data itself. All procedures are integrated into a processing chain with feedback loops and combined with conventional logical and statistical
checks, which enables it to detect small errors that normally pass unnoticed. The algorithms are also adapted
to incorporate the short time steps of the original data to retain the potential for detailed process analyses.
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Keywords: |
climate |
microclimate |
Climate variability |
data quality |
Gonzalez, V.; Fries, A.; Rollenbeck, R.; Paladines, J.; Oñate-Valivieso, F. & Bendix, J. (2016): Assessment of deforestation during the last decades in Ecuador using NOAA-AVHRR satellite data. Erdkunde 70(No. 3), 217-235.
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DOI: 10.3112/erdkunde.2016.03.02
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Human activities during the last decades provoked a notable reduction in global forest cover. Knowing that
forest stands act as stock and sinks for carbon and other greenhouse gases, it is important to determine the existing forest
cover at country level and to calculate annual deforestation rates. This work uses NOAAsatellite images in a resolution of
1 km x 1 km to classify the surface of continental Ecuador in “forest” – “non-forest” pixels and to estimate the annual
deforestation rate from 1986 to 2001 as well as from 2001 to 2008. The method is based on a decision tree algorithm that
includes different spectral bands of the NOAA-AVHRRsensor and additional topographic and meteorological parameters.
The results show that the total forest cover of continental Ecuador was reduced from 48.1 % in 1986 to 36.8 % in 2008. The
calculated annual deforestation rates indicate that forest reduction increased during the last decade. The most affected area
is the Coastal Lowland, due to the enhanced population pressure, followed by the Amazon Basin, not only caused by the
governmental supported oil and mining industry, but also due to the uncontrolled timber extraction. The Andean Highland
has been less affected, because the major parts of this region were deforested before, during the Pre-Columbian-Era.
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Keywords: |
Ecuador |
NOAA-AVHRR |
remote sensing |
deforestation |
image pre-processing |
forest cover |
Makowski Giannoni, S.; Trachte, K.; Rollenbeck, R.; Lehnert, L.; Fuchs, J. & Bendix, J. (2016): Atmospheric salt deposition in a tropical mountain rainforest at the eastern Andean slopes of south Ecuador – Pacific or Atlantic origin?. Atmospheric chemistry and physics 16, 10241-10261.
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DOI: 10.5194/acp-16-10241-2016
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Sea salt (NaCl) has recently been proven to be of the utmost importance for ecosystem functioning in Amazon lowland forests because of its impact on herbivory, litter decomposition and, thus, carbon cycling. Sea salt deposition should generally decline as distance from its marine source increases. For the Amazon, a negative east–west gradient of sea salt availability is assumed as a consequence of the barrier effect of the Andes Mountains for Pacific air masses. However, this generalized pattern may not hold for the tropical mountain rainforest in the Andes of southern Ecuador. To analyse sea salt availability, we investigated the deposition of sodium (Na+) and chloride (Cl?), which are good proxies of sea spray aerosol. Because of the complexity of the terrain and related cloud and rain formation processes, sea salt deposition was analysed from both, rain and occult precipitation (OP) along an altitudinal gradient over a period between 2004 and 2009. To assess the influence of easterly and westerly air masses on the deposition of sodium and chloride over southern Ecuador, sea salt aerosol concentration data from the Monitoring Atmospheric Composition and Climate (MACC) reanalysis data set and back-trajectory statistical methods were combined. Our results, based on deposition time series, show a clear difference in the temporal variation of sodium and chloride concentration and Na+???Cl? ratio in relation to height and exposure to winds. At higher elevations, sodium and chloride present a higher seasonality and the Na+???Cl? ratio is closer to that of sea salt. Medium- to long-range sea salt transport exhibited a similar seasonality, which shows the link between our measurements at high elevations and the sea salt synoptic transport. Although the influence of the easterlies was predominant regarding the atmospheric circulation, the statistical analysis of trajectories and hybrid receptor models revealed a stronger impact of the north equatorial Atlantic, Caribbean, and Pacific sea salt sources on the atmospheric sea salt concentration in southern Ecuador. The highest concentration in rain and cloud water was found between September and February when air masses originated from the north equatorial Atlantic, the Caribbean Sea and the equatorial Pacific. Together, these sources accounted for around 82.4?% of the sea salt budget over southern Ecuador.
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Keywords: |
chloride |
sodium |
rain |
Nutrient deposition |
Occult precipitation |
transport modelling |
Back trajectories |
Correa, A.; Windhorst, D.; Crespo, P.; Celleri, R.; Feyen, J. & Breuer, L. (2016): Continuous versus event based sampling: How many samples are required for deriving general hydrological understanding on Ecuador's páramo region?. Hydrological Processes 30(22), 4059-4073.
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DOI: 10.1002/hyp.10975
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Abstract:
Abstract:
As a consequence of the remote location of the Andean páramo is knowledge on their hydrologic functioning limited, notwithstanding this alpine tundra ecosystem act as water towers for a large fraction of the society. Given the harsh environmental conditions in this region is year-round monitoring cumbersome, and it would be beneficially if the monitoring needed for the understanding of the rainfall-runoff response could be limited in time. To identify the hydrological response and the effect of temporal monitoring a nested (n?=?7) hydrological monitoring network was set up in the Zhurucay catchment (7.53?km2), south Ecuador. The research questions were: (1) can event sampling provide similar information in comparison to continuous monitoring, and (2) if so, how many events are needed to achieve a similar degree of information? A subset of 34 rainfall runoff events was compared to monthly values derived from a continuous monitoring scheme from December 2010 to November 2013. Land cover and physiographic characteristics were correlated with eleven hydrological indices. Results show that despite some distinct differences between event and continuous sampling, both datasets reveal similar information; more in particular the monitoring of a single event in the rainy season provides the same information as continuous monitoring, while during the dry season 10 events ought to be monitored.
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Keywords: |
Paramo |
Andes |
hydrologic response |
catchment hydrology |
sampling design |
Mosquera, G.; Celleri, R.; Lazo, P.; Vaché, K.; Perakis, S. & Crespo, P. (2016): Combined use of isotopic and hydrometric data to conceptualize ecohydrological processes in a high-elevation tropical ecosystem. Hydrological Processes xxx, xxx.
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DOI: 10.1002/hyp.10927
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Abstract:
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.
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Keywords: |
Andes |
hydrological processes |
isotopes |
ecohydrological processes; |
Mosquera, G.; Segura, C.; Vaché, K.; Windhorst, D.; Breuer, L. & Crespo, P. (2016): Insights into the water mean transit time in a high-elevation tropical ecosystem. Hydrology and Earth System Sciences (HESS) 20(7), 2987-3004.
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DOI: 10.5194/hess-20-2987-2016
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Abstract:
Abstract:
This study focuses on the investigation of the mean transit time (MTT) of water and its spatial variability in a tropical high-elevation ecosystem (wet Andean páramo). The study site is the Zhurucay River Ecohydrological Observatory (7.53?km2) located in southern Ecuador. A lumped parameter model considering five transit time distribution (TTD) functions was used to estimate MTTs under steady-state conditions (i.e., baseflow MTT). We used a unique data set of the ?18O isotopic composition of rainfall and streamflow water samples collected for 3 years (May 2011 to May 2014) in a nested monitoring system of streams. Linear regression between MTT and landscape (soil and vegetation cover, geology, and topography) and hydrometric (runoff coefficient and specific discharge rates) variables was used to explore controls on MTT variability, as well as mean electrical conductivity (MEC) as a possible proxy for MTT. Results revealed that the exponential TTD function best describes the hydrology of the site, indicating a relatively simple transition from rainfall water to the streams through the organic horizon of the wet páramo soils. MTT of the streams is relatively short (0.15–0.73 years, 53–264 days). Regression analysis revealed a negative correlation between the catchment's average slope and MTT (R2?=??0.78, p?<?0.05). MTT showed no significant correlation with hydrometric variables, whereas MEC increases with MTT (R2?=??0.89, p?<?0.001). Overall, we conclude that (1) baseflow MTT confirms that the hydrology of the ecosystem is dominated by shallow subsurface flow; (2) the interplay between the high storage capacity of the wet páramo soils and the slope of the catchments provides the ecosystem with high regulation capacity; and (3) MEC is an efficient predictor of MTT variability in this system of catchments with relatively homogeneous geology.
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Keywords: |
Paramo |
mean transit time |
hydrological processes |
Iniguez, C.; Rausche, S.; Cueva, A.; Sánchez-Rodríguez, A.; Espinosa, C. & Breuer, L. (2016): Shifts in leaf litter breakdown along a forest–pasture–urban gradient in Andean streams. Ecology and Evolution 6(14), 4849-4865.
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DOI: 10.1002/ece3.2257
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Abstract:
Abstract:
Tropical montane ecosystems of the Andes are critically threatened by a rapid land-use change which can potentially affect stream variables, aquatic communities, and ecosystem processes such as leaf litter breakdown. However, these effects have not been sufficiently investigated in the Andean region and at high altitude locations in general. Here, we studied the influence of land use (forest–pasture–urban) on stream physico-chemical variables (e.g., water temperature, nutrient concentration, and pH), aquatic communities (macroinvertebrates and aquatic fungi) and leaf litter breakdown rates in Andean streams (southern Ecuador), and how variation in those stream physico-chemical variables affect macroinvertebrates and fungi related to leaf litter breakdown. We found that pH, water temperature, and nutrient concentration increased along the land-use gradient. Macroinvertebrate communities were significantly different between land uses. Shredder richness and abundance were lower in pasture than forest sites and totally absent in urban sites, and fungal richness and biomass were higher in forest sites than in pasture and urban sites. Leaf litter breakdown rates became slower as riparian land use changed from natural to anthropogenically disturbed conditions and were largely determined by pH, water temperature, phosphate concentration, fungal activity, and single species of leaf-shredding invertebrates. Our findings provide evidence that leaf litter breakdown in Andean streams is sensitive to riparian land-use change, with urban streams being the most affected. In addition, this study highlights the role of fungal biomass and shredder species (Phylloicus; Trichoptera and Anchytarsus; Coleoptera) on leaf litter breakdown in Andean streams and the contribution of aquatic fungi in supporting this ecosystem process when shredders are absent or present low abundance in streams affected by urbanization. Finally, we summarize important implications in terms of managing of native vegetation and riparian buffers to promote ecological integrity and functioning of tropical Andean stream ecosystems.
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Keywords: |
stream water |
decomposition |
Aquatic Pollution |
Spreuer, J. (2016): Ektomykorrhizapilze in Kiefernplantagen im Páramo von Ecuador Universität Tübingen, bachelor thesis
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Abstract:
Abstract:
Im Páramo der ecuadorianischen Anden wurden in einer Höhe zwischen 3000 m und 4000 m Plantagen mit Pinus patula angelegt. Dadurch wurden im Páramo normalerweise nicht vorkommende Ektomykorrhizapilze eingeführt. Mithilfe morphologischer und molekularer Methoden wurden die Ektomykorrhiza-Arten in drei Plantagen in der Nähe von Cuenca untersucht. Insgesamt wurden fünf verschiedene Ektomykorrhizapilze gefunden, von denen drei bis auf die Art bestimmt werden konnten: Thelephora terrestris, Suillus luteus, Inocybe jacobi, eine Sebacina-Art und eine nicht identifizierte Art. Thelephora terrestris war in allen drei Plantagen die am häufigsten vorkommenden Ektomykorrhiza-Art. Die Ektomykorrhizagemeinschaft dieser Plantagen ist also sehr artenarm im Vergleich zu natürlichen Standorten. Diese Beobachtung wird von anderen Studien in Kiefernplantagen der südlichen Hemisphäre bestätigt.
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Paramo |
Pinus patula |
ectomycorrhizas |
Ochoa Moreno, S.; Paul, C. & Knoke, T. (2016): Warum Kleinbauern in Ecuador die Landnutzung diversifizieren. Allgemeine Forst Zeitschrift für Waldwirtschaft und Umweltvorsorge 71(13), 31-34.
Urgiles , N.; Haug, I.; Setaro, S. & Aguirre, N. 2016: Introduction to Mycorrhizas in the Tropics with Emphasis on the Montane Forest in Southern Ecuador.: Estudios de Bioversidad 4 (EDILOJA Cía. Ltda., Loja).
Schlaeppi, K.; Bender, S.F.; Mascher, F.; Russo, G.; Patrignani, A.; Camenzind, T.; Hempel, S.; Rillig, M.C. & van der Heijden, M.G. (2016): High-resolution community profiling of arbuscular mycorrhizal fungi. New Phytologist xx, xx.
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DOI: 10.1111/nph.14070
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Abstract:
Abstract:
Summary
Community analyses of arbuscular mycorrhizal fungi (AMF) using ribosomal small subunit
(SSU) or internal transcribed spacer (ITS) DNA sequences often suffer from low resolution or
coverage. We developed a novel sequencing based approach for a highly resolving and specific profiling of AMF communities.
We took advantage of previously established AMF-specific PCR primers that amplify a
c. 1.5-kb long fragment covering parts of SSU, ITS and parts of the large ribosomal subunit
(LSU), and we sequenced the resulting amplicons with single molecule real-time (SMRT)
sequencing.
The method was applicable to soil and root samples, detected all major AMF families and
successfully discriminated closely related AMF species, which would not be discernible using
SSU sequences. In inoculation tests we could trace the introduced AMF inoculum at the
molecular level. One of the introduced strains almost replaced the local strain(s), revealing
that AMF inoculation can have a profound impact on the native community.
The methodology presented offers researchers a powerful new tool for AMF community
analysis because it unifies improved specificity and enhanced resolution, whereas the drawback of medium sequencing throughput appears of lesser importance for low-diversity groups
such as AMF.
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Keywords: |
arbuscular mycorrhiza |
mycorrhiza |
Crowther, T. & et, a. (2015): Mapping tree density at a global scale. Nature 525(7568), 201-205.
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DOI: 10.1038/nature14967
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Abstract:
Abstract:
The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuousmap of forest tree density at a global scale. This mapreveals that the global numberof trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate
regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization.
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Keywords: |
tree density |
Slik, F. & et, a. (2015): An estimate of the number of tropical tree species. PNAS 112(24), 7472-7477.
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DOI: 10.1073/pnas.1423147112
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Abstract:
Abstract:
The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database
from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ?40,000 and ?53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ?19,000–25,000 tree species. Continental Africa is relatively depauperate with a minimumof ?4,500–6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.
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Keywords: |
tree species richness |
tree species |
Silva, B.; Strobl, S.; Beck, E. & Bendix, J. (2016): Canopy evapotranspiration, leaf transpiration and water use efficiency of an Andean pasture in SE-Ecuador – a case study. Erdkunde 70(1), 5-18.
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DOI: 10.3112/erdkunde.2016.01.02
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Abstract:
Abstract:
The relationship between canopy-level evapotranspiration (ETSci) and leaf-level transpiration (Tleaf) as well as photosynthesis (Pleaf) for a homogeneous tropical montane pasture was analyzed over five days using a combination of methods involving a laser scintillometer and a porometer. Weather conditions ranged from overcast to sunny during the period of study. The gas exchange of the leaves of the dominant pasture grass Setaria sphacelata (transpiration vs. photosyn¬thetic CO2 net uptake ) was measured with a porometer and physiologically interpreted on the background of microclimate variables (photosynthetic active radiation (PAR) as proxy for total light intensity, temperature, water vapor deficit of the air) and soil moisture data. Water use efficiency (WUE, photosynthetic CO2 net uptake vs water loss by leaf transpiration) of the pasture was used to analyze the grass’ range of response to the environmental variables of the research area. PAR and water vapor deficit of the air (VPD) appeared to be the determinant factors for Tleaf and ETSci. WUE for the Setaria sphacelata pasture ranged from 1.9 to 5.8 ?mol CO2 mmol-1 H20 day-1 and is particularly low during periods of high VPD combined with enhanced insolation during cloudless periods. ET measurements collected by the scintillometer demonstrated a strong correlation with water flux calculated using the Penman-Monteith approach (TPM) (r² = 0.95). Also, Tleaf measured with the porometer showed reasonable coincidence with the ET observations (r² = 0.78). Values of ETSci ranged from 2.26 to 4.96 mm day-1 and Tleaf ranged from 0.83 to 2.41 mm day-1, but only ETSci showed good correspondence with the available energy (net radiation). The lower correlation between Tleaf and canopy-level ETSci compared to that between ETSci and TPM was tested against contaminations from the adjacent fetch area of the scintillometer path, but no effects were found. Likewise, soil water limitations of Tleaf could be ruled out. Therefore, different correlations of ETSci and Tleaf with the incoming energy and VPD may be traced back to a direct effect of the VPD on ET in contrast to its indirect effect on Tleaf which is additionally regulated by physiological processes in the leaf stomata.
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Keywords: |
Porometry |
Setaria |
Evapotranspiration |
scintillometry |
Adams, M. & Fiedler, K. (2016): Low Herbivory among Targeted Reforestation Sites in the Andean Highlands of Southern Ecuador.. PLoS ONE 11(3), e0151277.