Environmental changes in biodiversity hotspot ecosystems of
South Ecuador: RESPonse and feedback effECTs (FOR2730)

Abstract:

Anthropogenic activities have produced changes in natural ecosystems worldwide. In tropical regions in South America, industrialization of cities and forest clearance via burning are the main activities releasing pollutants into the atmosphere and inducing changes in nutrient deposition patterns and climate of primary forests. Nitrogen (N) and phosphorus (P) are considered the main limiting nutrients of plant growth since their availability is vital for net primary productivity. Therefore, any change in N or P availability in soils would likely alter important mechanisms of forests dynamics such as growth and survival. Changes in soil pH (acidity), nutrient cycles and altered nutrient stocks affect N and P availability and affect various physiological processes of trees. Although low levels of nutrient deposition have been reported for montane forests in southern Ecuador (ca. 5 kg ha–1 for N, 0.49 kg ha–1 for P), even these levels are expected to lead to changes in forest structure and dynamics over the long term. The responsiveness of forest to changes in resource availability varies with forest age and successional status, as well as life stage of the plant. Young plants (tree seedlings) should be more responsive to changes in nutrient availability than mature forest trees. Further, any demographic response is more likely to be visible in seedlings before mature trees because of the more rapid dynamics of seedlings. Therefore, I studied the regeneration dynamics of montane forest to understand which nutrient-related processes are involved in the growth and establishment of seedlings at both the individual and community levels. The Ecuadorian NUtrient Manipulation EXperiment (NUMEX) has been designed to study the response of montane forest to moderate fertilization. The experiment has been set up over an elevation range across three main study sites (1000 m. a.s.l: Bombuscaro; 2000 m. a.s.l: San Francisco; 3000 m. a.s.l: Cajanuma) within the Podocarpus National Park and San Francisco Reserve. The factorial experiment consists of four blocks containing four experimental plots (N, P, NP and control) in every study site (16 plots per elevation). Fertilization has been done since 2008, adding moderate quantities of fertilizer (50 kg ha–1 y–1 of N and/or 10 kg ha–1 y–1 of P). Three different approaches were used to assess the seedling community and common species responses to fertilization. First, the seedling community was monitored in natural forest at 2000 m over three consecutive years (2011 – 2013). In 192 monitoring subplots (1m2 each) in San Francisco, all seedlings and saplings were mapped and tagged. Measurements of height, diameter, herbivory and leaf production were recorded for all individuals, and the number of recruited and dead seedlings was counted every year. Second, allocation patterns and stoichiometry of seedlings of the six most common species were determined across the elevation gradient. Naturally occurring seedlings of the following species were harvested: Clarisia racemosa and Pouteria torta in Bombuscaro, Graffenrieda emarginata and Palicourea angustifolia in San Francisco and Grafferieda harlingii and Hedyosmum purpuracens in Cajanuma. Morphology (biomass allocation, herbivory and foliar areas such as SLA, LAR and LA) and foliar stoichiometry (nutrient contents and N:P ratios) were recorded and analyzed. Third, a reciprocal transplantation experiment (STE) within the NUMEX experimental plots monitored seedlings of the most common species in Bombuscaro, (Pouteria torta), to assess specific responses in seedling performance over one year. These three levels of analysis showed differential responses of the species community and common species to fertilization. Contrary to lowland forests, the community seedlings in this montane forest showed a moderate response. The density of seedling individuals decreased following nutrient addition, as a result of lower recruitment in treatments plots, but mortality was unaffected. Consequently, density-dependent mechanisms activated by additional N uptake did not show evidence of being a main driver to changes in species density. The community of seedlings did not show significant growth in response to fertilization although seedlings were higher in the N treatment. However, N addition increased herbivory over all seedlings and plots, which could have masked other seedlings growth responses. Common species seem to be well adapted to the relatively poor soils since these species were not favored by nutrient addition showing no change in growth or leaf traits. Over the long-term, common species might lose their dominance by being less competitive than faster growing species. However, it would need a longer period of monitoring under continued fertilization to produce visible shifts in community composition. Species-specific responses are hard to determine in such species rich communities. Therefore, analyses of the six common species were conducted to complement the community-level study. Leaf morphology and foliar stoichiometry were assessed from harvested seedling from the experimental plots. Both N and P had effects on seedling traits, suggesting co-limitation of N and P in montane tree species in all elevations. However, foliar N:P ratios and the more frequently response to P addition indicated this nutrient might be more limiting than N along the gradient. Responsiveness of the studied species varied between the six species. Stronger foliar P concentration compared with N in all species but Pouteria torta suggested higher P consumption in montane forest species, similar to the responses of several other tropical plant species after P addition. Increased herbivory was only evident in the opposite responses of G. emarginata (N and N+P addition) and P. angustifolia (P addition) at 2000 m suggesting that plant selection by herbivores is driven by resource quality. Most of the species had higher belowground biomass in root fractions following fertilization, except for G. harlingii at 3000 m, the only species that showed significant increase in aboveground biomass after nutrient addition. Pouteria torta seedlings showed no significant changes in species performance after fertilization one year after establishment of the STE. Pouteria seems to be well-adapted to poor soils, since N and P addition did not alter foliar nutrient concentrations. Nevertheless, N and N+P addition significantly increased mortality and diameter growth rates. P addition resulted in higher leaf area loss and shifted carbon allocation to root growth. These responses indicated consequences in the competitive strength in the understory and recruitment success of Pouteria torta. However, the ambiguous response in some attributes (growth and herbivory) not related with mortality made it difficult to predict the future abundance of this species in long term. In conclusion, complementary studies demonstrated that specific nutrient limitation for N or P in montane species seem not to be a rule in rich species ecosystems although nutrient addition did alter some pattern of growth and survival. Thus, nutrient fertilization might affect various mechanisms and dynamics of plant communities, the balance of which will only play out over long time scales.

Abstract:

Tropische und subtropische Trockenwälder zählen zu den bedrohtesten tropischen Ökosystemen (MILES et al. 2006). Sie bieten für mehr Menschen Siedlungsraum als humide Waldgebiete und sind dadurch besonders stark dem menschlichen Einfluss ausgesetzt. Die vorliegende Arbeit beschäftigt sich mit der Entwicklung der Baumverjüngung in der tumbesischen Trockenwaldregion Südecuadors und Nordperus und dem Einfluss der dort üblichen Waldweide. In Reservaten in der Provinz Loja (Ecuador) und im angrenzenden Nationalpark Cerros de Amotape auf peruanischer Seite wurde in 288 Parzellen (je 4 m²) die Baumregeneration registriert. Die Parzellen waren im Trockenwald mit den Vegetationsformen halb-laubabwerfend und laubabwerfend verteilt; zudem wurde die Hälfte der Parzellen eingezäunt, um den Einfluss der Beweidung auf die Regeneration zu erfassen. Die Aufnahmen fanden in einem Zeitraum von zwei Jahren zweimal während der Trockenzeit und zweimal kurz nach der Regenzeit statt, beginnend mit einer Aufnahme in der Trockenzeit 2014. Es wurden die Individuen markiert und die Artnamen dokumentiert, Höhen und abgestorbene Individuen wurden aufgenommen. Aus den Daten wurden die Höhenzuwächse, die Mortalitätsraten sowie die Shannon- und Evennessindices berechnet. Insgesamt wurden 93 Arten aus 36 verschiedenen Familien aufgenommen. Die Ergebnisse zeigten für den Erhebungszeitraum eine höhere Individuenanzahl während der Regenzeit, die Anzahl der Arten war im Vergleich zur Trockenzeit jedoch geringer. Die Diversität unterschied sich nicht signifikant zwischen den Jahreszeiten. Bei Betrachtung der Aufnahmen stach das zweite Monitoring mit besonders hohen Individuenanzahlen heraus. Zwischen den Waldtypen gab es einen signifikanten Unterschied in der Höhe der Verjüngung, sowie im Höhenzuwachs von der dritten auf die vierte Aufnahme. Die offenen und eingezäunten Flächen unterschieden sich ebenso in den Höhen und dem Höhenzuwachs signifikant. Die Diversität unterschied sich mit und ohne Zäunung und bei den beiden Waldtypen nicht eindeutig. Die Ergebnisse können unter anderem durch die Struktur des Altbestandes, dessen Einfluss auf die Strahlung, die Temperatur und die Feuchtigkeit, und wiederum deren Einfluss auf die Verjüngung erklärt werden. Lokale und regionale floristische Diversität und Zusammenstellung, Wachstumsformen, Phänologie und Demographie der Verjüngungspflanzen sind in weiten Formen besonders abhängig von der Hydrologie. Beweidung andererseits lenkt die Ausbreitung Verbiss resistenterer Arten, welche durch Reduzierung der Weidetiere zur Walderhaltung beitragen können. Diese Studie soll als lokale Forschungsarbeit zum besseren Verständnis des Ökosystems Trockenwald beitragen. Die gesammelten Erkenntnisse sollen später der Entwicklung nachhaltiger Landnutzungssysteme dienen, welche den Fortbestand dieses gefährdeten Habitats sichern.

Abstract:

Tropical forests and the trees as their principal components have been investigated in detail. However, due to its complexity, their interactions, adaptations and response to climate variations require much more research. In this study, dendrochronological techniques were applied to evaluate the potential of tree-rings from tropical tree species as climate records. Two ecosystems with very distinct climate scenarios were selected from a dry and humid forest in southern Ecuador. A comparative analysis between these two forest types was performed by applying three dendrochronological methods. First, Tree Ring Width (TRW) measurements from tree species with distinct ring boundaries were dated to develop ring-width chronologies. Second, stable carbon isotopes (?13C) were measured from whole-wood and alpha-cellulose of dated annual tree-rings. Finally, concentrations of more than 23 chemical elements were determined from individual dated tree-rings after dissolving the wooden material in HNO3. The results showed the high potential of tropical tree species as climate archives, Bursera graveolens and Maclura tinctoria for the dry forest and Cedrela montana for the humid forest. Radial growth variations in tree species from the dry forest revealed a strong and reliable precipitation signal. Then, for these tropical regions, the first ring-width based wet-season precipitation reconstruction over the past century was developed, and spatial correlations unraveled a strong connection to the climatic conditions of the central Pacific precipitation and temperature variability. Interseries correlations of the TRW from the trees of the humid forest revealed a weak common signal. Stable carbon isotopes evidenced higher climate sensitivity than TRW measurements in the humid forest. However, to infer a reliable climate reconstruction from stable carbon isotopes, more ?13C time series were needed. ?13C values from whole-wood and alpha-cellulose reflected local and regional signals of precipitation and humidity. Meanwhile, nutrient concentration in the wood was higher in the dry forest, but common patterns and trends of nutrients were more distinct in the humid forest. For both study sites, two groups of nutrients with opposite radial distribution were identified (Group 1: Ca, Sr, Ba, Ga; and Group 2: K, P, Rb). In conclusion, TRW of tree species from the dry forest have a high paleoclimate potential, especially to reconstruct precipitation amounts in arid zones of southern Ecuador. Stable carbon isotopes constitute a promising tool to perform climatic reconstructions in both ecosystems. Finally, the valuable historical information of nutrient concentration evidenced in tree-rings opens promising ways to study tree growth dynamics especially in the humid forest.

Abstract:

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.

Abstract:

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.

Abstract:

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.

Abstract:

The worldwide demand for large scale biodiversity monitoring systems is challenging for recent remote sensing techniques. For monitoring changes in species as well as functional diversity the consideration of ecosystem processes is crucial. Herbivory as a focal function in tropical forest ecosystems is therefore being investigated in this study. Aim of the study is to reveal the potential of remotely sensed image textures for predicting herbivory. For this leaf area loss (LAL) due to herbivory has been quantified in different vegetation layers of a tropical mountain forest in the Ecuadorian Andes. The study area is a structurally highly complex region along an elevation gradient from 1000 to 3000 m a.s.l. with undisturbed primary forest and disturbed forest fragments within agriculturally used land. It has been proven that LAL has similar patterns as herbivore abundance over the elevation gradient showing it to be a possible proxy for herbivore abundance. Further results show a correlation of LAL data and canopy cover thus local forest structure. Correlations between LAL and image textures as a proxy for vegetation structure were stronger than with pixel wise derived spectral values only. Unveiling the high potential of image textures as a surrogate for herbivory and ecosystem function.

Abstract:

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.

Abstract:

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.

Abstract:

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.

Abstract:

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.

Abstract:

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.

Abstract:

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

Abstract:

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.

Abstract:

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).