Publications
Found 861 publication(s)
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Ließ, M.; Hitziger, M. & Huwe, B. (2014): The Sloping Mire Soil-Landscape of Southern Ecuador: Influence of Predictor Resolution and Model Tuning on Random Forest Predictions. Applied and Environmental Soil Science 2014(603132), 10 pages.
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DOI: 10.1155/2014/603132
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Abstract:
Abstract:
The sloping mire landscape of the investigation area, in the southern Andes of Ecuador, is dominated by stagnic soils with thick organic layers. The recursive partitioning algorithm Random Forest was used to predict the spatial water stagnation pattern and the thickness of the organic layer from terrain attributes. Terrain smoothing from 10 to 30m raster resolution was applied in order to obtain the best possible model. For the same purpose, several model tuning parameters were tested and a prepredictor selection with the R-package Boruta was applied. Model versions were evaluated and compared by 100 repetitions of the calculation of the residual mean square error of a five-fold cross-validation. Position specific density functions of the predicted soil parameters were then used to display prediction uncertainty. Prepredictor selection and tuning of the Random Forest algorithm in some cases resulted in an improved model performance.We therefore recommend testing prepredictor selection and tuning to make sure that
the best possible model is chosen.This needs particular emphasis in complex tropical mountain soil-landscapes which provide a real challenge to any soil mapping approach but where Random Forest has proven to be successful due to the testing of model tuning and prepredictor selection.
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Keywords: |
regionalization |
digital soil map |
organic layer |
stagnic properties |
Kottke, I.; Setaro, S.; Haug, I.; Herrera, P.; Cruz, D.; Suarez, J.P.; Fries, A.; Adams, J.; Gerique, A.; Homeier, J. & Werner, F.A. (2013): Mycorrhiza Networks Promote Biodiversity and Stabilize the Tropical Mountain Rain Forest Ecosystem: Perspectives for Understanding Complex Communities. In: J. Bendix, E. Beck, A. Bräuning, F. Makeschin, R. Mosandl, S. Scheu, W. Wilcke. (eds.): Ecosystem Services, Biodiversity and Environmental Change in a Tropical Mountain Ecosystem of Sou l ( 221), Springer Verlag, Heidelberg, 438.
Kottke, I.; Kovács, G. & Eötvös Lorand University (2013): Mycorhrizae - Rhizosphere determinants of plant communities: What can we learn from the tropics?. In: Amram Eshel und Tom Beeckman (eds.): Plant Roots - The Hidden Half (Vierte Auflage ), CRC Press, Buch.
Bendix, J. & Univ Marburg (2004): Extremereignisse und Klimavariabilität in den Anden von Peru und Ecuador . Geographische Rundschau 1(2004), 10-16.
Brehm, G.; Strutzenberger, P. & Fiedler, K. (2013): Phylogenetic diversity of geometrid moths decreases with elevation in the tropical Andes. Ecography 36(11), 1247-1253.
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DOI: 10.1111/j.1600-0587.2013.00030.x
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Abstract:
Abstract:
Species diversity of geometrid moths (Lepidoptera, Geometridae) has previously been shown to be extremely and constantly high along a continuously forested elevational gradient in the Andes of southern Ecuador. We analysed samples taken from 32 sites between 1999 and 2011 in northern Podocarpus National Park and adjacent areas from 1020 to 2916 m a.s.l. We conjecture that high elevation habitats were historically mostly colonised by species from lower elevations, and that environmental filtering (e.g. through host plant specificity or temperature tolerance) constrained colonisation from lower elevations, which would yield a pattern of elevationally decreasing phylogenetic diversity. We analysed elevational phylogenetic patterns by means of: 1) the nearest-taxon index (NTI), 2) DNA barcode-based terminal branch lengths (TBLs) from maximum-likelihood phylogeny, 3) the subfamily composition of the local assemblages, and 4), the rarefied number of morphologically defined genera per site.
We counted a total of 1445 species. NTI values significantly increased with elevation, both in a conventional and a rarefaction approach. TBLs decreased significantly with elevation. Subfamily composition profoundly changed with elevation, particularly expressed as an increased proportion of the subfamily Larentiinae and decreased fractions of Sterrhinae and Geometrinae. The number of genera in equally rarefied species resamples significantly decreased with elevation. We conclude that environmental filtering indeed contributed to an altitudinal decrease in moth phylodiversity, but these constraints prevented only relatively few clades from colonising high elevation habitats.
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Keywords: |
moths |
Andes |
Bendix, J.; Beck, E.; Bräuning, A.; Makeschin, F.; Mosandl, R.; Scheu, S. & Wilcke, W. 2013: Ecosystem Services, Biodiversity and Environmental Change in a Tropical Mountain Ecosystem of South Ecuador.: Ecological Studies 221 (Springer-Verlag, Berlin Heidelberg).
Knoke, T.; Calvas, B.; Ochoa Moreno, S.; Onyekwelu, J. & Griess, V. (2013): Food production and climate protection—What abandoned lands can do to preserve natural forests. Global Environmental Change 23, 1064-1072.
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DOI: 10.1016/j.gloenvcha.2013.07.004
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Abstract:
Abstract:
Approaches to reconciling food production with climatic and environmental protection often require agricultural intensification. The production of more food per unit of agricultural land through "sustainable intensification" is intended to enable the protection of natural ecosystems elsewhere (land sparing). However, there are problems associated with agricultural intensification; such as soil erosion, eutrophication or pollution of water bodies with chemicals, landscape homogenization and loss of biodiversity; for which solutions have not yet been found. Reuse of abandoned agricultural lands – which are abundant throughout the world – to address the rising demand for food is a potentially important alternative, which up to now has been widely ignored. To test the power of this alternative, equilibrium economic land allocation to various land-use practices by risk-avoiding tropical farmers in Ecuador was simulated. The reestablishment of pastures on abandoned cattle lands lowered prices for pasture
products, and also triggered conversion of existing pasture into cropland. The resulting land-use change increased total annual food production in a moderate scenario from the current level of 17.8–23.1 petacalories (10^15 calories), which amounted to a production increase of 30%. At the same time, there was a 19% reduction in the amount of payments to farmers required to preserve tropical forests – one of the world’s greatest terrestrial carbon stores.
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Keywords: |
Ecuador |
land use |
ecosystem services |
Alnus acuminata |
land change modelling |
abandoned pasture |
grassland |
climate change |
carbon stocks |
conservation payments |
Makowski, S.; Rollenbeck, R.; Fabian, P. & Bendix, J. (2013): Complex topography influences atmospheric nitrate deposition in a neotropical mountain rainforest. Atmospheric environment 79, 385-394.
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DOI: 10.1016/j.atmosenv.2013.06.023
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Abstract:
Abstract:
Future increase of atmospheric nitrogen deposition in tropical regions is expected to have negative impacts on forests ecosystems and related biogeochemical processes. In tropical mountain forests topography causes complex streamflow and rainfall patterns, governing the atmospheric transport of
pollutants and the intensity and spatial variability of deposition. The main goal of the current study is to link spatio-temporal patterns of upwind nitrogen emissions and nitrate deposition in the San Francisco Valley (eastern Andes of southern Ecuador) at different altitudinal levels. The work is based on Scanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) retrieved-NO2 concentrations, NOx biomass burning emissions from the Global Fire Emissions Database (GFEDv3), and regional vehicle emissions inventory (SA-INV) for urban emissions in South America. The emission data is used as input for lagrangian atmospheric backward trajectory modeling (FLEXTRA) to model the transport to the study area. The results show that NO3 À concentrations in occult precipitation samples are significantly correlated to long-range atmospheric secondary nitrogen transport at the highest meteorological stations (MSs) only, whereas for NO3 À concentrations in rain samples this correlation is more pronounced at the lower MSs. We conclude that ion concentrations in occult precipitation at the uppermost MSs are mainly linked to distant emission sources via the synoptic circulation impinging the more exposed higher sites. Lower correlations close to the valley bottom are due to a lower occult precipitation frequency and point to a contamination of the samples by local pollution sources not captured by the used emission data sources.
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Keywords: |
wet deposition |
nitrogen |
nitrate |
Southern Ecuador |
Curatola Fernández, G.F.; Silva, B.; Adams, J.; Thies, B. & Bendix, J. (2013): Bracken fern frond status classification in the Andes of southern Ecuador: combining multispectral satellite data and field spectroscopy. International Journal of Remote Sensing 34, 7020-7037.
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DOI: 10.1080/01431161.2013.813091
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Abstract:
Abstract:
In the anthropogenic fire-disturbed ecosystem of the San Francisco Valley in the Andes of southeastern Ecuador, dense stands of an aggressive invasive weed, the southern bracken fern (Pteridium arachnoideum and Pteridium caudatum), dominate the landscape. To secure sustainable land management in the region, a comprehensive understanding of bracken spatial-distribution patterns and life cycle dynamics is crucial. We investigated the possibility of detecting bracken-infested areas and frond status (live, fungi-infected, and dead) by means of a high-resolution QuickBird scene from October 2010 and spectral signatures based on field spectroscopy. After image pre-processing, a two-step classification procedure first delineates the bracken-infested area by means of a maximum-likelihood hard classification. The probability-guided unmixing classifier with field-derived end-members is applied in the second step to obtain the fractional cover of the different frond statuses per pixel. The results showed that the areas infested by bracken could be distinguished from the other land-cover classes with high accuracy (overall accuracy of 0.9973). Also, the three frond statuses could be accurately classified at the sub-pixel level. The ‘dead’ class was the dominant frond status at the time of image acquisition (October 2010). We conclude that the extreme dry spell in October 2010 was particularly responsible for this dominance.
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Keywords: |
Bracken fern |
Field spectroscopy |
Southern Ecuador |
QuickBird |
Frond status |
Soft classification |
Potthast, K. (2013): Implications of land-use change and pasture management on soil microbial function and structure in the mountain rainforest region of southern Ecuador TU Dresden , phd thesis
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DOI: http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-115503
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Abstract:
In the present thesis, implications of pasture establishment, fertilization and abandonment on soil C and nutrient dynamics were investigated for the mountain rainforest region of southern Ecuador. Over the past decades the natural forest of the study area has been threatened by conversion to cattle pastures. However, the soil fertility of these extensively grazed pastures (active pastures) declines continuously during pasture use. The invasion of bracken fern (Pteridium arachnoideum) leads to pasture abandonment when bracken becomes dominant. In order to reveal the mechanisms behind the deterioration of soil fertility, biotic and abiotic soil properties and their interaction were analyzed along a land?use gradient (natural forest – active pasture – abandoned pasture).
The ecosystem disturbance of the mountain rainforest through pasture use changed the microbial function and structure, and affected soil CO2?C fluxes. Annually, 2 Mg soil CO2?C ha?1 were additionally emitted from the pasture land. This acceleration in soil respiration rates was related to accelerated rates of microbial C mineralization and fine?root respiration. The high?quality, N?rich above? and belowground residues of the pasture grass (S. sphacelata, C4?plant), especially the huge fine?root biomass, provided a high C and N availability for soil microbes. Compared to the forest, increased soil pH and accelerated base saturation were further factors beneficial for soil microbial growth and metabolism of the upper mineral soil at active pastures. Three times higher amounts of microbial biomass C and a significant shift in the microbial community structure towards a higher relative abundance of Gram(?)? bacteria and fungi were observed.
Long?term pasture use and the invasion of bracken (C3?plant) diminished beneficial effects for microbes, causing a significant decrease in the C, net, and gross N mineralization rates as well as a two?third reduction in the microbial biomass. A preferential substrate utilization of grass?derived C4 by the soil microbes resulted in a rapid decline of the C4?pool. As a consequence, the less available C3?pool from bracken and former forest increased its dominance in the SOC?pool, further decreasing pasture productivity and finally causing pasture abandonment. The lower quality and quantity of above? and belowground residues of the bracken (high lignin content, C/N) resulted in resource?limited conditions that influenced the microbial function to greater extent than their structure. The microbial structure seemed to be sensitive mainly to soil pH along the land?use gradient. Thus, a disconnection between microbial structure and function was identified.
Fertilization experiments were conducted both in the lab and in the field to evaluate the impact of urea and/or rock phosphate amendment on SOM dynamics and on pasture productivity of active pastures. After combined fertilization the pasture yield was most efficiently increased by 2 Mg ha?1 a?1, indicating a NP?limitation of grass growth. Furthermore, the fodder quality was improved by a higher content of P and Ca in the grass biomass. The microorganisms of the active pasture soil responded with an adaptation of their structure to the increased substrate availability in the short term, but did not change their initial functions in the long term. After urea/ rock phosphate addition a significant increase in the relative fungal abundance was detected, but neither a microbial limitation of energy nor of N or P was observed. However, urea addition accelerated gaseous losses of soil CO2?C in the short term.
In the study area, pronounced alterations in ecosystem functioning due to land?use changes were detected, especially in soil C and N cycling rates. For a sustainable land?use in this region it is crucial to prevent pasture degradation and to rehabilitate degraded pastures in order to protect the prevailing mountain rainforest ecosystem. It is of crucial importance for active pasture soils to maintain or even increase resource availability, being one indicator of soil fertility. In this context, the soil organic matter has to be retained in the long?term to maintain high microbial activity and biomass, and thus pasture productivity. A moderate fertilization with urea and rock phosphate can be a first step to provide continuous nutrient supply for grass growth and to strengthen livestock health through increased fodder quality. However, the risk of further additional emissions of soil CO2?C due to increased loads of urea fertilizer application has to be kept in mind. Overall, for the establishment of a sustainable land?use management the control of bracken invasion and an adjusted nutrient management are needed. Further investigations on the reduction of soil nutrient losses and increased nutrient use efficiencies of plants, such as combined planting with legumes or the usage of cultivars with special nutrient acquisition strategies, should be in the focus of future work.
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Keywords: |
bracken |
land use |
pasture |
microbial activity |
yield |
abandoned pasture |
Setaria sphacelata |
soil microbial biomass |
Camenzind, T. & Rillig, M.C. (2013): Extraradical arbuscular mycorrhizal fungal hyphae in an organic tropical montane forest soil. Soil Biology and Biochemistry 64, 96-102.
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DOI: 10.1016/j.soilbio.2013.04.011
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Abstract:
Abstract:
Previous research from the tropics indicates that AMF may be well adapted to organic soils and even represent the dominant mycorrhizal form, though the extraradical part of the symbiosis was omitted as in most other tropical studies. Our study aims at characterizing the extraradical part of arbuscular mycorrhizal fungi (AMF) in a highly organic tropical montane forest soil in Southern Ecuador. Based on recent studies on the interaction of AM fungal hyphae and litter we hypothesized that within the organic layer AM hyphae grow in close contact with decomposing material. To test this idea, AM fungal hyphal distribution in the organic layer was determined by directly staining roots and decomposing leaves and extracting hyphae from the remaining particulate organic material. AM and non-AM fungal hyphae were analyzed, as well as root colonization patterns. Our results showed that AMF indeed represented the dominant mycorrhizal form with an average root colonization of 43%. The extraradical AM hyphal length ranged from 2 to 34 m g?1 soil with a mean of 10.4 m g?1 soil (equals 3.1 m cm?3 soil), and therefore exceeded root length about 13-fold. As hypothesized, 29% of AM extraradical hyphae were closely attached to decomposing leaves. These hyphae were mainly located at the leaf surface, though in some parts leaf veins and inner leaf tissues were colonized. More than half of AM hyphal biomass was detected on the root surface, a pattern potentially driven by the predominant Paris-type AMF. Non-AM fungal hyphae colonized decomposing material to a significantly greater extent, though hyphal length attached to roots was equal. This study supports the adaptation of AMF to highly organic soils in the tropics and the existence of a widespread extraradical mycelium, which is not readily detectable by standard methods. The close association with decomposing leaves most likely improves direct nutrient uptake from decomposed material and points to a potential indirect contribution of AMF to the decomposition process.
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Keywords: |
soil characteristics |
mycorrhizal fungi |
fungi |
mycorrhizal colonisation |
decomposition |
litter decomposition |
AM fungi |
arbuscular mycorrhiza |
mycorrhiza |
soil |
mountain forest |
soil N availability |
tropical soils |
Haug, I.; Setaro, S. & Suarez, J.P. (2013): Reforestation sites show similar and nested AMF communities to an adjacent pristine forest in a tropical mountain area of South Ecuador . PLOS ONE 8, e63524.
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DOI: 10.1371/journal.pone.0063524
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Abstract:
Arbuscular mycorrhizae are important for growth and survival of tropical trees. We studied the community of arbuscular mycorrhizal fungi in a tropical mountain rain forest and in neighbouring reforestation plots in the area of Reserva Biológica San Francisco (South Ecuador). The arbuscular mycorrhizal fungi were analysed with molecular methods sequencing part of the 18S rDNA. The sequences were classified as Operational Taxonomic Units (OTUs). We found high fungal species richness with OTUs belonging to Glomerales, Diversisporales and Archaeosporales. Despite intensive sampling, the rarefaction curves are still unsaturated for the pristine forest and the reforestation plots. The communities consisted of few frequent and many rare species. No specific interactions are recognizable. The plant individuals are associated with one to ten arbuscular mycorrhizal fungi and mostly with one to four. The fungal compositions associated with single plant individuals show a great variability and variety within one plant species. Planted and naturally occurring plants show high similarities in their fungal communities. Pristine forest and reforestation plots showed similar richness, similar diversity and a significantly nested structure of plant-AMF community. The results indicate that small-scale fragmentation presently found in this area has not destroyed the natural AMF community, at least yet. Thus, the regeneration potential of natural forest vegetation at the tested sites is not inhibited by a lack of appropriate mycobionts.
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Keywords: |
forest |
reforestation |
AM fungi |
Brehm, G.; Strutzenberger, P. & Fiedler, K. (2013): Phylogenetic diversity of geometrid moths decreases with elevation in the tropical Andes. Ecography 36, 001-007.
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Species diversity of geometrid moths (Lepidoptera, Geometridae) has previously been shown to be extremely and constantly high along a continuously forested elevational gradient in the Andes of southern Ecuador. We analysed samples taken from 32 sites between 1999 and 2011 in northern Podocarpus National Park and adjacent areas from 1020 to 2916 m a.s.l. We conjecture that high elevation habitats were historically mostly colonised by species from lower elevations, and that environmental filtering (e.g. through host plant specificity or temperature tolerance) constrained colonisation from lower elevations, which would yield a pattern of elevationally decreasing phylogenetic diversity. We analysed elevational phylogenetic patterns by means of: 1) the nearest-taxon index (NTI), 2) DNA barcode-based terminal branch lengths (TBLs) from maximum-likelihood phylogeny, 3) the subfamily composition of the local assemblages, and 4), the rarefied number of morphologically defined genera per site.
We counted a total of 1445 species. NTI values significantly increased with elevation, both in a conventional and a rarefaction approach. TBLs decreased significantly with elevation. Subfamily composition profoundly changed with elevation, particularly expressed as an increased proportion of the subfamily Larentiinae and decreased fractions of Sterrhinae and Geometrinae. The number of genera in equally rarefied species resamples significantly decreased with elevation. We conclude that environmental filtering indeed contributed to an altitudinal decrease in moth phylodiversity, but these constraints prevented only relatively few clades from colonising high elevation habitats.
Jantz, N.; Homeier, J.; León Yánez, S.; Moscoso, A. & Behling, H. (2013): Trapping pollen in the tropics — Comparing modern pollen rain spectra of different pollen traps and surface samples across Andean vegetation zones. Review of Palaeobotany and Palynology 193, 57-69.
Villota, A.; León Yánez, S. & Behling, H. (2012): Vegetation and environmental dynamics in the Páramo of Jimbura region in the southeastern Ecuadorian Andes during the late Quaternary. Journal of South American Earth Sciences 40, 85-93.
Pena Herrera, J.M. (2013): Response of N, P, organic C and Cl concentrations in soil solution to varying precipitation in a tropical montane rain forest of Ecuador University of Berne, Geographic Institute, master thesis
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The current climate change in the tropical Andean rain forests in south Ecuador alters the distribution of rain events with increasing dry and wet phases. The present research focuses on the concentration response of some elements to signicant changes on rainfall distribution. It seeks to determine whether changes in the concentrations of elements in an ecosystem of a rainforest are an eect of dilution by precipitation or other factors that may be aecting these variations, such as microbiological activities. The study examines chloride, ammonium, nitrate, phosphate, total organic carbon (TOC), dissolved organic nitrogen (DON), and dissolved organic phosphorus (DOP) in soil solution as well as the ratio of organic nitrogen to organic carbon (C : N) in soil solution samples taken in a tropical rain forest of Ecuador. Soil samples were taken weekly from 1998 to 2007, both below the organic layer and 15 and 30 cm into the mineral layer. Concentrations were measured with a chloride electrode , Continuous Flow Analyzer (CFA for ammonium, nitrate, DON, and DOP) and Total Organic Carbon Analyzer. The results were analyzed with statistical
software packages R and SPSS using statistical methods of descriptive statistics and ANOVA. The average weekly precipitation was 38.73 mm and weekly precipitation varied between 0 and 155.2 mm. The variation of chloride concentrations served as reference to detect dilution/concentration effects of the other elements because it is assumed that chloride concentrations behave inversely proportional to the volume of water in soil. Thus, the higher the precipitation the lower is the concentration of chloride in soil solutions. I found that the mineral elements presented similar concentration variations as chloride indicating the strong if not exclusive eect of dilution. The phosphate concentrations were an exception showing irregular variation. Measurement problems due to the low P concentrations, often below the detection limit of the instrument may be the explanation for such irregularities. The variation in chloride-normalized organic components diered from that of chloride. The concentrations of TOC, DON and C : N ratio showed a fairly steep increase with increasing precipitation, especially observable at 15 cm depth in the mineral soil and in some cases also at 30 cm depth. A small TOC consumption by the microbial community during rewetting, a strong microbial TOC production or increased leaching of TOC to the mineral soil are possible explanations for this result. My results demonstrate that the response of inorganic N and P species is mainly driven by concentration/dilution eects while for organic compounds microbial activity in relation to soil moisture was an additional factor controlling the concentrations.
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Keywords: |
hydrochemistry |
Q2 |
ECSF |
mineral N |
nitrogen |
nitrate |
soil solution |
phosphorus |
DOC |
climate change |
Utiger, C. (2013): Der wassergebundene Phosphorkreislauf in einem tropischen Bergwaldökosystem: Konzentrationen, Flüsse und zeitliche Trends Geographisches Institut, Universität Bern, bachelor thesis
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Um das Vorhandensein und den Transport chemischer Elemente auf der Erde zu beschreiben, wird das Konzept der biogeochemischen Kreisläufe angewandt. Ein solches Element ist Phosphor, das wegen seiner Wichtigkeit als limitierendes oder co-limiterendes Element für das Pflanzenwachstum in tropischen Regenwäldern ausgewählt wurde. Am Beispiel eines Einzugsgebietes im tropischen Bergregenwald von Ecuador wird untersucht, wie sich die Phosphorkonzentrationen und Phosphorflüsse entlang des wassergebundenen Kresilaufs vom Freilandniederschlag bis hin zum Oberflächenabfluss sowohl zeitlich wie auch räumlich verhalten. Die untersuchten Daten umfassen die Wasserflüsse und die Konzentrationen von Orthophosphat und totalem gelösten Phosphat zwischen 1998 und 2010 als monatliche Mittel. Die räumliche Verteilung wird mit der Darstellung der Messwerte in Boxplots und der Suche nach räumlichen Mustern analysiert. Um nach saisonalen Prozessen zu suchen, wird einerseits ein lineares Modell, bestehend aus einer Sinus- und einer Cosinus-Funktion gebildet und auf Signfikanz und Aussagekraft, d.h. Erklärung der Variabilität durch das Modell anhang des Anteils an der Gesamtvariation getestet. Anderseits wird die Autokorrelation der Daten auf ein saisonales Muster untersucht. Ein allfälliger langfristiger Trend wird mit dem saisonalen Kendall-Test gesucht. Bei der Analyse der räumlichen Verteilung zeigt sich, dass sich die größten Phosphor-Konzentrationen und -Flüsse zwischen Bestandesniederschlag und organischer Auflage bewegen. Zudem ist der Eintrag durch den Freilandniederschlag größer als der Austrag im Oberflächenabfluss. Bei allen Wasserflüssen wurde eine jährliche Saisonalität festgestellt. Bei den Konzentrationen ist ein antizyklisches Verhalten zu den Wasserflüssen zu erkennen. Der Freilandniederschlag weist keine Saisonalität auf. Die größten Saisonalitäten sind zwischen Krone und organischer Auflage zu finden. Die Konzentrationen in den Saugkerzen und im Oberflächenabfluss sind nur schwach durch saisonale Prozesse geprägt. Bei den Flüssen zeigt nur der Bestandesniederschlag deutlich jährliche Saisonalität. Die Analyse der zeitlichen Trends zeigte keine langfristigen Trends, die auf eine Änderung externer Faktoren zurückzuführen sind. Interne Veränderungen im Pflanzenwachstum könnten für eine Zunahme im Stammabfluss und eine Abnahme der Lysimeterkonzentrationen (unter der organischen Auflage) verantwortlich sein. Bei der Analyse der Feueraktivität als möglicher Quelle für Phosphoreintrag wurden einzelne signifikante Beziehungen mit den Phosphorkonzentrationen gefunden.
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Keywords: |
hydrochemistry |
Q2 |
ECSF |
phosphorus |
seasonality |
temporal trends |
Hertel, T. (2012): Tree Seed Procurement and Management in the Province of Loja Institute of Silviculture, Technische Universität München, master thesis
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South America hosts 22% of the world´s forests with its unique biological diversity. Among all countries Ecuador is considered being the country with the highest biodiversity. But unsustainable land use and forestry practices threaten this diversity. Up to today Ecuador has the highest deforestation rate of the South American continent. To combate against those high forest losses wide-ranged reforestation has to take place but is still lacking in Ecuador. The reforestation efforts up to now do not compensate the high losses in forest cover. 90% (3500ha) of the annual reforestation in Ecuador is taking place in the Andean region (FAO 2006, 2011).
A common tool to reinstall the forest cover is plantings. To this day 140,000 ha of forest plantations exist in the Andes of Ecuador. The commonly used species are Eucalyptus globulus, Pinus radiata and Pinus patula. Just recently Ecuadorian organizations paid particular attention to tree species native to Ecuador and their reforestation potential. The major obstacle to use native species on a larger scale for reforestation is the lack of adequate knowledge about their physiological and silvicultural traits. Information about appropriate seed storage, propagation methods and silvicultural treatment options has to be acquiered, applied and its experience communicated.
Tree seed programs provide a valuable framework to deal with such sets of questions and research needs. The Danish International Development Agency (DANIDA) has over 50 years of experience in the development and establishment of national tree seed programs. Their development framework is used as an orientation in the course of this thesis to frame a regional seed program for the provincial region of Loja.
The general objectives of this thesis are to evaluate the current seed procurement and management methods in the Province of Loja and to develop a concept for regional seed program for the province of Loja which is practicable and adapted to the local circumstances.
Data on the current practices was gathered through a questionnaire survey and structured observation among the provincial tree nurseries. National and regional forestry strategies and plans were revised to understand the encountered situation. To develop the regional seed program the national tree seed program framework from Danida was consulted. This study assesses the main areas of improvement of the provincial seed management and highlights local facts in need for special consideration in the scope of a regional seed program. Furthermore essential parts and how to best implement those in a regional seed program are discussed.
Major results involve the formulation of four main areas of improvement common for all surveyed tree nurseries of the province: Infrastructure, workforce, documentation and seed handling itself. The individual performances of the nurseries were ranked to get a clearer picture about the production efficiency. The survey also revealed the variety of tree species produced. Regarding the regional seed program the results picture the Gobierno Provincial de Loja (GPL) as a suitable entity to be in charge of the program. Moreover important stakeholders beneficiary for the program were detected and an exemplary distribution of activities among them was conducted.
The principal contributions of this thesis consist in conducting a systematic evaluation of the current status of the seed sector in southern Ecuador and particularly in the Province of Loja for the first time, and in providing the provincial government with an elaborated concept to improve the seed management. Additionally the developed ranking scheme can serve as a guideline for further nursery performance evaluations.
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Keywords: |
native species |
reforestation |
tropical montane forest |
Biodiversity conservation |
tree seeds |
DFG Research Unit 816 (2013): TMF Newsletter, Issue 19. Laboratory for Climatology and Remote Sensing (LCRS), University of Marburg, Marburg, Germany.
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DOI: 10.5678/lcrs/for816.cit.1233
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Abstract:
Abstract:
20 groups of scientists representing a multitude of scientific disciplines summarize major results of their research in this last issue of the TMF Newsletter: They report about science-directed and sustainable land-use systems and present protocols for optimization of sustainable forest and pasture management. Specific reactions of species and of the ecosystem tropical mountain forest (TMF) to increasing loads of nutrient input are shown. The researchers also summarize effects of altered precipitation and temperatures on nitrogen fluxes as well as on plant and animal diversity. They furthermore improved their hydrological models of water fluxes. Landscape parameters and forest dynamics were analyzed to improve landslide models. New animal species and mycorrhiza types are presented, mycorrhiza biomass were determined, and it was analyzed which mycorrhizae foster young trees. How environmental change influences climate and the ecosystem is demonstrated. The milestones achieved in the data warehouse are visualized. The researchers also offer new methods and introduce species to successfully monitor global change impacts.
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Keywords: |
Ecuador |
FOR816 |
Newsletter |
Biodiversity |
Windhorst, D.; Waltz, T.; Timbe, E.; Frede, H. & Breuer, L. (2013): Impact of elevation and weather patterns on the isotopic composition of precipitation in a tropical montane rainforest. Hydrol. Earth Syst. Sci. 177, 409-419.
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DOI: 10.5194/hess-17-409-2013
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Abstract:
Abstract:
This study presents the spatial and temporal variability of ?18O and ?2H isotope signatures in precipitation of a south Ecuadorian montane cloud forest catchment (San Francisco catchment). From 2 September to 25 December 2010, event sampling of open rainfall was conducted along an altitudinal transect (1800 to 2800 m a.s.l.) to investigate possible effects of altitude and weather conditions on the isotope signature.
The spatial variability is mainly affected by the altitude effect. The event based ?18O altitude effect for the study area averages ?0.22‰ × 100 m?1 (?2H: ?1.12‰ × 100 m?1). The temporal variability is mostly controlled by prevailing air masses. Precipitation during the times of prevailing southeasterly trade winds is significantly enriched in heavy isotopes compared to precipitation during other weather conditions. In the study area, weather during austral winter is commonly controlled by southeasterly trade winds. Since the Amazon Basin contributes large amounts of recycled moisture to these air masses, trade wind-related precipitation is enriched in heavy isotopes. We used deuterium excess to further evaluate the contribution of recycled moisture to precipitation. Analogously to the ?18O and ?2H values, deuterium excess is significantly higher in trade wind-related precipitation. Consequently, it is assumed that evaporated moisture is responsible for high concentrations of heavy isotopes during austral winter.
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Keywords: |
climate |
rainwater chemistry |
hydrological processes |
isotopes |
Bouanani, S. (2013): Aluminium in der Bodenlösung eines tropischen Bergregenwaldes in Südecuador: Auswirkungen von Staubeinträgen auf Al-Speziierung und Toxizität Johannes Gutenberg University Mainz, diploma thesis
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Zu Beginn der Untersuchungen wurden im ersten Schritt die freien Aluminiumkonzentrationen mit Hilfe der Donnan Membran Technik bestimmt.
Anschließend wurden im zweiten Schritt die gemessenen freien Aluminiumkonzentrationen mit den modellierten Aluminiumkonzentrationen verglichen. Hierbei stellte sich heraus, dass die Werte vergleichbar sind und somit das Programm Visuell Minteq zur Modellierung der Aluminiumspeziierung eingesetzt werden konnte. Es wurde weiter festgestellt, dass der Anteil des freien Aluminiums an der gesamten Aluminiumkonzentration mit der Bodentiefe zunimmt. Der Anteil des freien Aluminiums an der gesamten Al-Konzentration betrug in der Bodenlösung unterhalb der organischen Auflage in allen untersuchten Plots lediglich 0% bis 0,96% (Mittelwert 0,0451%), während er im Mineralboden, bedingt durch geringe DOC-Werte, zwischen 0% und 29,11% (15 cm Tiefe) sowie zwischen 0% und 36,88% (30 cm Tiefe) schwankte.
Der dritte Schritt galt der Untersuchung des Ca/Al Verhältnisses. Das Ergebnis zeigte hier, dass das freie molare Ca2+/Al3+ Verhältnis durch die Calciumdüngung nur geringfügig beeinflusst wird und über dem von Cronan & Grigal (1995) als kritisch betrachtetem Wert von <1 liegt. Calcium tritt daher vermutlich als wachstumslimitierender Faktor auf. Eine direkte Aluminiumtoxizität ist in den untersuchten Bodenlösungen nicht bzw. nur in geringem Maße festzustellen gewesen
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Keywords: |
simulation model |
microcatchment 2 |
ECSF |
NUMEX |
DOC |
calcium |
pH |
aluminium |
DFG Research Unit 816 (2012): TMF Newsletter, Issue 18. Laboratory for Climatology and Remote Sensing (LCRS), University of Marburg, Marburg, Germany.
Palomeque, X. (2012): Natural succession and tree plantation as alternatives for restoring abandoned lands in the Andes of Southern Ecuador: Aspects of facilitation and competition Technische Universität München, phd thesis
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Abandoned areas are emerging in many tropical regions as a consequence of deforestation and unsustainable land-use. These lands can be restored by natural succession (passive) or reforestation (active). Both alternatives where analyzed on three dominant types of successional sites (recently abandoned Pasture, Bracken, Shrub) in the tropical mountain forest in Southern Ecuador. The performance of several native species was evaluated for reforestation, including the effects of removal of competing herbaceous vegetation and seedlings pretreatment (e.g. fertilization, inoculation with arbuscular mycorrhiza fungi). The results showed an inhibited natural succession on the Pasture site which can be improved by planting well adapted species as A. acuminata. On the Bracken- and Shrub-sites the natural succession may be optimized by enrichment planting of M. pubescens and T. chrysantha.
Silva, B. & Bendix, J. (2012-07-26). Monitoring and modelling competing grassland species using very-high and high-resolution remote sensing in the Andes of Ecuador. Presented at IEEE International Geoscience and Remote Sensing Symposium - IGARSS, Munich, Germany.
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A method is presented for monitoring and modeling of two competing grassland species (the southern bracken fern and the pasture grass Setaria). The method consists of estimating leaf area index for each species by using field observations and measurements, very-high and high-resolution images. The higher level of information at very-high resolution is used for identification of homogenous cover, on which a single species predominates. Consequently, ground measurements are used with high-resolution data to calculate species-specific regression functions between the normalized difference vegetation index and leaf area index. These data are used in a simulation run to extend the knowledge on occurrence and competition of bracken fern and Setaria pasture in the southern Ecuador
Setaro, S.; Garnica, S.; Herrera, P. & Goeker, M. (2011): A clustering optimization strategy to estimate species richness of Sebacinales in the tropical Andes based on molecular sequences from distinct DNA regions. Biodiversity and Conservation 21, 2269-2285.
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DOI: 10.1007/s10531-011-0205-y
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Fungi are believed to be diverse in the tropics, but because many groups are
only known from their DNA sequences this hampers comparative diversity studies. We
investigated mycorrhizal Sebacinales (Basidiomycota) of 67 individuals of Ericaceae and
Orchidaceae in a tropical mountain ecosystem in Southern Ecuador to provide a ?rst
estimate of whether these fungi are particularly diverse in the Northern Andes. We par-
tially sequenced the internal transcribed spacer (ITS) and large subunit (LSU) regions of
the nuclear ribosomal DNA and analyzed them together with all Sebacinales sequences
available from GenBank. The clustering optimization technique was used to determine
clustering parameters that maximize the comparability between molecular operational
taxonomic units (MOTUs) obtained from the distinct loci. Sampling effort and species
richness were estimated with rarefaction-accumulation curves and non-parametric esti-
mation using Chao2 and compared between Southern Ecuador and France. Clustering
optimization indicated that a 1% LSU distance threshold corresponds to the commonly
used 3% dissimilarity threshold for ITS, and that a clustering algorithm close to single-
linkage clustering is optimal. The resulting clusters show that about 8?9% of observed Sebacinales MOTUs occur in the study area and that most of these MOTUs are endemic
(74%). The widespread MOTUs from Southern Ecuador were also found in Panama, North
America and Europe. The estimation of species richness revealed unsaturated sampling of
Sebacinales in general and also in our study area. Our results suggest a high diversity of
Sebacinales associated with Ericaceae and Orchidaceae at the study site in Southern
Ecuador, but no hotspot of Sebacinales in comparison with other areas.
Homeier, J.; Hertel, D.; Camenzind, T.; Cumbicus Torres, N.; Maraun, M.; Martinson, G.; Poma, N.; Rillig, M.C.; Sandmann, D.; Scheu, S.; Veldkamp, E.; Wilcke, W.; Wullaert, H. & Leuschner, C. (2012): Tropical Andean Forests Are Highly Susceptible to Nutrient Inputs - Rapid Effects of Experimental N and P Addition to an Ecuadorian Montane Forest. PLoS ONE 7, e47128.
Bendix, J.; Paladines, B.; Ribadeneira Sarmiento, M.; Romero, L.M.; Valarezo, C. & Beck, E. (2010-01-25). Benefit sharing by research, education and knowledge transfer - a success story of biodiversity research in southern Ecuador. Presented at UNESCO IYB Biodiversity Science-Policy Conference, UNESCO Headquarters, Paris.
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The paper reports of the successful knowledge transfer of the DFG (German research foundation) research unit RU816/Ecuador in the context of the Access and Benefit Sharing (ABS) of the Convention on Biological Diversity (CBD).
It introduces the approach of the RU816 and its scientific education and capacity building. It further presents the shared access to research facilities, technology and information as well as the potentials of a transfer of basic research to application and the public education and awareness. The authors conclude with a description of the DFG and the ABS process.
Roos, K.; Hamer, U.; Potthast, K.; Tischer, A. & Beck, E. (2011-10-07). Ecología de los pastos y efectos de su manejo en los Andes en el Sur de Ecuador. Presented at Annual status symposium of the RU816, Loja, Ecuador.
Beck, E. (2012-09-24). (Why) Do we need Legal Regulations for Biodiversity Research. Presented at 21st International Symposium "Biodiversity and Evolutionary Biology" of the German Botanical Society, Mainz, Germany.
Beck, E.; Roos, K.; Hamer, U.; Potthast, K.; Tischer, A.; Silva, B. & Bendix, J. (2012-02-24). Ecological Aspects of Repasturisation of Abandoned Mountain Pastures in South Ecuador. Presented at Annual Conference of the Society for Tropical Ecology, University of Erlangen, Germany.