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

Abstract:

We analyzed the stocks of Ca, Mg, P, and S in tree rings of Cedrela montana Moritz ex Turcz in order to evaluate the dynamics of element input to a lower montane rain forest in South Ecuador. Samples were taken by a Pressler drill from the living tree (n=5). Afterwards tree rings were separated and digested with concentrated HNO3 under pressure (Heinrichs et al.,1986). Concentrations of Ca and Mg were determined by atomic absorption spectroscopy (AAS), concentrations of P and S by inductively coupled plasma optical emission spectrometry (ICP-OES), respectively. Mean element concentrations in tree rings between 1957 and 2005 were 2.2 g kg-1 for Ca, 1.1 g kg-1 for P and S and 0.4 g kg-1 for Mg. Radial distribution of element concentrations was heterogeneous with exception of the tree rings close to the phloem, where concentrations were generally higher. The pattern of annual radial increment showed significant growth peaks related to strong La Niña events. Also concentrations of P and S peaked during the La Niña events of 1989, 1996, and 2000. For Ca and Mg a similar effect was observed with a time shift of one year. Highest Ca peaks during the monitored period were associated with the 1974 La Niña event, which was also the strongest event on the record. We conclude that tree rings are a suitable tool for recording element inputs of Ca, Mg, P, and S at lower montane rain forests of South Ecuador. Furthermore we found element inputs and growth signals linked to the ENSO cycle.

Abstract:

Catchment-scale runoff generation involves a complex interaction of physical and chemical processes operating over a wide distribution of spatial and temporal scales. Understanding runoff generation is challenged by this inherent complexity ? the more uncertain step of predicting the hydrologic response of catchments is that much more challenging. Many different hypotheses have been implemented in hydrological models to capture runoff generation processes and provide hydrologic predictions. These concepts have been developed based on extended field observations. Here we propose inferring water flux understanding and catchment exploring through the application of a variety of available hydrological models as a mechanism to build upon and extend models that have been developed to capture particular hydrological processes. We view this ensemble modeling strategy as particularly appropriate in ungauged catchments. The study is carried out in a tropical montane rainforest catchment in Southern Ecuador. The catchment is 75 km2 and is covered by forest in the south, while the northern slopes have been partly deforested for grazing. Annual rainfall is highly variable, reaching up to 5700 mm per year in the upper parts of the catchment. To explore the dominating runoff processes, an ensemble of 6 hydrological models with different structures applied over different levels of both spatial and temporal detail was developed. The ensemble includes spatially lumped (HBV-light), semi-distributed (HEC-HMS, CHIMP, SWAT, LASCAM) and a fully distributed model (HBV-N-D). The hydro-statistical toolkit WETSPRO was used to characterize simulated and observed hydrographs. Estimated baseflow indices, flow minima and maxima, flow duration curves and cumulative errors were generated and compared among the ensemble of models. This process facilitated the exploration of processes controlling runoff generation, enabled an evaluation of the applicability of the screened models to tropical montane rainforests, and provided the capacity to evaluate and explain where different models failed.

Abstract:

The understanding of the hydrological functioning of a tropical ecosystem allows to evaluate the consequences of a changed land use. On the east-facing slope of the Andes in Ecuador between 1900 and 2150 m a.s.l. I studied the above- and belowground driving variables of the water budget. The objectives were to determine the elements of the water budget experimentally and with an optimized model and to elucidate the hydraulically relevant processes along five 20 m-long transects in three 8-13 ha-large microcatchments under montane rain forest. Water fluxes were weekly measured between April 1998 and April 2001, the mean annual evapotranspiration was calculated with a budget approach. For the canopy, I determined the water storage capacity and assessed the influence of the vegetation density and epiphyte coverage on interception and canopy evaporation of the precipitation. The vegetation density was approximated by the leaf area index [LAI] and the fraction of the precipitation falling through gaps of the canopy. In addition, I modeled throughfall and stemflow by adapting the analytical canopy model of Gash. In the soil, I determined the saturated hydraulic conductivity and the water contents. To calculate the reaction of surface flow on precipitation events and to identify the soil processes controlling the surface flow, I compared a ?black box? (NAMOD) with a ?semi-empirical? (TOPMODEL) model approach. The mean water storage capacity of the dry leaves is 1.91±1.94 mm and that of the trunks 0.041±0.02 mm. The LAI ranges from 5.2 to 9.3. Epiphytes - mainly mosses - cover up to 80% of the trunk and branch surfaces. The fraction of precipitation falling through gaps of the canopy correlates significantly with the interception loss (r = -0.77, n = 40). During dry periods the mosses and lichens tend to decrease the water storage capacity of the trunks. The saturated hydraulic conductivity decreases drastically at the border between organic layer and mineral soil where it was highly variable. The high stone content of, on average, 40Vol.% has a substantial effect of the flow regime. Based on the results of the precipitation-surface flow modeling the hydraulically effective soil layer can be separated into two water reservoirs (organic layer and mineral soil). The water flow in the soil occurres rapidly in lateral direction in the organic layer and/or much slower, mainly vertically in the deeper mineral soil layers. Water flow in the latter soil layers during strong rain events is little likely, because the organic layer is rapidly saturated favoring interflow. The weekly surface flow measurements result in an overestimation of the annual water output from the catchments because high flow events were overrepresented. The mean annual surface flow in the three catchments, calculated on the basis of daily modeled flow rates, ranges between 27 and 46% of the precipitation. The annual evaporation, calculated on the basis of daily surface flow rates, ranges between 1281 and 1889 mm, i.e. 54-73% of the precipitation. My results demonstrate that rapid lateral water flow in the organic layer of the soil dominates the flow regime. The destruction of the forest and removal of the organic layer would result in soil erosion and increased intensity of high-flow events.

Abstract:

Tropical mountain regions are characterized by strong spatial climate gradients which together with the limited amount of data and knowledge of the underlying processes hinder the management of the water resources. Especially for regional-scale prediction it is important to identify the dominant factors controlling the rainfall?runoff response and link those to known spatial patterns of climate, soils, and vegetation. This study analyzes the rainfall?runoff relation of 13 intensively monitored micro-catchments in the Andes of southern Ecuador. The results of this study show that streamflow in the southern cordillera of the Ecuadorian Andes, above 2500 m a.s.l., primarily consists of subsurface flow. The yearly amount of streamflow is controlled by the annual rainfall depth, whereas the temporal distribution is mainly governed by the lateral saturated hydraulic conductivity, the soil water retention and the antecedent soil moisture content. Anthropogenic effects were found insignificant, with the exception in one of the studied micro-catchment. Effect of land use changes in most of the micro-catchments did not reflect in the shape of the flow duration curve because either the spatial extent of human impact was small and/or the overall basin slope was less than 20%.

Abstract:

The near surface humidity in a megadiverse mountain ecosystem in southern Ecuador is examined on the basis of Relative Humidity (RH) measurements inside the natural mountain forest and at open sites along an altitudinal gradient from 1700 to 3200 m. The main methodological aim of the current study is to generate a humidity regionalization tool to provide spatial datasets on average monthly mean, minimum and maximum RH, Specific Humidity (q) and Specific Saturation Deficit (DS) by using observation data of RH. The maps based on data of the period 1999–2009 are needed by ecological projects working on various plots where no climate station data are available. The humidity maps are generated by combining a straightforward detrending technique with a Digital Elevation Model and a satellite-based land cover classification which also provides the relative forest cover per pixel. The topical aim of the study is to investigate the humidity distribution and structure of both manifestations of our ecosystem (pastures and natural vegetation) with special considerations to the ecosystem regulation service by converting natural forest into pasture. The results reveal a clear differentiation over the year, partly triggered by the change of synoptic weather situation but also by land cover effects. Humidity amplitudes are particularly low during the main rainy season when cloudiness and rainfall are high, but markedly pronounced in the relative dry season when daily irradiance and outgoing nocturnal radiation causes distinct differences between the land cover units. Particularly the upper pasture areas gained by slash and burn of the natural forest exhibit the lowest humidity values while the humidity inside the mountain forest is significantly higher due to the regulating effects of the dense vegetation. Thus, clearing the forest clearly reduces the regulation function (regulating ecosystem services) of the ecosystem which might become problematic for reforestation under future global warming.

Abstract:

Stem diameter increments of the broadleaved deciduous tree species Tabebuia chrysantha were measured with high-resolution dendrometers in a tropical lower montane forest and in a dry forest in southern Ecuador, the latter showing a distinct dry season. Those analyses were complemented by wood anatomical studies on regularly collected microcores to determine the season of active cambial growth and the time of formation of annual growth boundaries. The length of the cambial active period varied between 3 and 7 months at the tropical lower montane forest and 2 and 4 months in the dry forest, respectively. During dry days, amplitudes of daily stem diameter variations correlated with vapour pressure deficit. During October and November, inter-annual climate variations may lead to dry and sunny conditions in the tropical lower montane forest, causing water deficit and stem diameter shrinkage in T. chrysantha. The results of the climate– growth analysis show a positive relationship between tree growth and rainfall as well as vapour pressure deficit in certain periods of the year, indicating that rainfall plays a major role for tree growth.

Abstract:

This diploma thesis deals with the purpose to create a dataset of soil texture (sand and clay content) as input parameter for a SWAT model. For this a senstitvity study on this parameter in the model was carried out and a statistical approach based on a digital terrain analysis to regionalize soil profile data was driven. The results show that the sensitivity of this model (CLM) limits to extreme content ratios of sand and clay. The resulting maps of the regionalization is discussed critical due to various factors: i) the number of used soil profile samples is to small ii) the accuracy of the DEM is to uncertain iii) the surface of the model region is highly textured (step slopes) and it should be considered wether the pedological processes are sorting soil substrate like in moderate regions, for which the concept of deriving soil properties in dependency of the terrain was proven.

Abstract:

Soil-landscapes are diverse and complex due to the interaction of pedogenetic, geomorphological and hydrological processes. The resulting soil profile reflects the balance of these processes in its properties. Early conceptual models have by now resulted into quantitative soil-landscape models including soil variation and its unpredictability as a key soil attribute. Soils in the Andean mountain rainforest area of southern Ecuador are influenced by hillslope processes and landslides in particular. The lack of knowledge on the distribution of soils and especially physical soil properties to understand slope failure, resulted in the study of this particular soil-landscape by means of statistical models relating soil to terrain attributes, i.e. predictive soil mapping. A 24 terrain classes comprising sampling design for soil investigation in mountainous areas was developed to obtain a representative dataset for statistical modelling. The soils were investigated by 56 profiles and 315 auger points. The Reference Soil Groups (RSGs) Histosol, Stagnosol, Umbrisol, Cambisol, Leptosol and Regosol were identified according to the World Reference Base for Soil Resources (WRB). Classification tree models and a probability scheme based on WRB hierarchy were applied to include RSG prediction uncertainty in a digital soil map. Histosol probability depended on hydrological parameters; highest Stagnosol probability was found on slopes < 40° and above 2146 m a.s.l. Poor model performance, probably due to the prediction of complex categories (RSGs) and WRB inconsequence (absolute and relative value criteria), led to the proposal of ?incomplete soil classification? by relating the thickness of the WRB?s diagnostic horizons as percentage to the upper 100 soil centimetres, including the organic layer. Typical diagnostic horizons histic, humic, umbric, stagnic and cambic were regionalised in their thickness and occurrence probability by classification and regression trees (CART). Prediction uncertainty was addressed with hundredfold model runs based on different random Jackknife partitions of the dataset. Whether the first mineral soil horizon displays stagnic properties or not, likely depends on physical soil properties in addition to terrain parameters. Incomplete soil classification resulted in histic and stagnic soil parts dominating the first 100 cm of the soil volume for most of the research area. While soil profiles and auger points were described in their horizon composition, thickness, Munsell colour and soil texture by finger method (FAO, 2006), soil cohesion, bulk density and texture by pipette and laser were analysed in soil profiles only. Texture results by pipette compared to laser method, showed the expected shift to higher silt and lower clay contents. Linear regression equations were adapted. Pedotransfer functions to predict physical soil properties from the bigger auger dataset analysed by field texture method only, could not be developed, because field texture analysis did not provide satisfying results. It was therefore not possible to correct its results with the more precise laboratory data. Comparing CART and Random Forest (RF) in their model performance to predict topsoil texture and bulk density as well as mineral soil thickness by hundredfold model runs with random Jackknife partitions, RF predictions resulted more powerful. Altitude a.s.l. was the most important predictor for all three soil parameters. Increasing sand/ clay ratios with increasing altitude, on steep slopes and with overland flow distance to the channel network are caused by shallow subsurface flow removing clay particles downslope. Deeper soil layers are not influenced by the same process and therefore showed different texture properties. Terrain parameters could only explain the spatial distribution of topsoil properties to a limited extent, subsoil properties could not be predicted at all. Other parameters that likely influence soil properties within the investigation area are parent material and landslides. Strong evidence was found that topsoil horizons did not form from the bedrock underlying the soil profile. Parent material changes within short distance and often within one soil profile. Landslides have a strong influence on soil-landscape formation in shifting soil and rock material. Soil mechanical and hydrological properties in addition to terrain steepness were hypothesized to be the major factors in causing soil slides. Thus, the factor of safety (FS) was calculated as the soil shear ratio that is necessary to maintain the critical state equilibrium on a potential sliding surface. The depth of the failure plane was assumed at the lower boundary of the stagnic soil layer or complete soil depth, depending on soils being stagnic or non-stagnic. The FS was determined in dependence of soil wetness referring to 0.001, 0.01, 0.1 and 3 mm/h net rainfall rate. Sites with a FS &#8805; 1 at 3 mm/h (complete saturation) were classified as unconditionally stable, sites with a FS < 1 at 0.001 mm/h as unconditionally unstable. The latter coincided quite well with landslide scars from a recent aerial photograph.

Abstract:

Over the past decades, the tropical mountain rainforest of southern Ecuador has been threatened by conversion to cattle pastures. Frequently, these pastures are invaded by bracken fern and abandoned when bracken becomes dominant. Changes in land-use (forest–pasture–abandoned pasture) can affect soil microorganisms and their physiological responses with respect to soil carbon and nutrient cycling. In situ investigations on litter decomposition and soil respiration as well as biogeochemical characterization of the soil were carried out to identify the driving factors behind. The conversion of forest to pasture induced a pronounced increase in CO2–C effluxes to 12.2 Mg ha-1 a-1 which did not decrease after abandonment. Soil microbial activity and biomass showed a different pattern with lowest values at forest and abandoned pasture sites. With 3445 mg kg-1 (0–5 cm) microbial biomass carbon (MBC by CFE-method), the active pasture had a more than three times higher value than forest and abandoned pasture, which was among the highest in tropical pasture soils. A shift in the microbial community structure (phospholipid fatty acid, PLFA) was also induced by the establishment of pasture land; the relative abundance of fungi and Gram-negative bacteria increased. PLFA fingerprints of the forest organic layer were more similar to pasture than to forest mineral soil. Chemical properties (pH value, exchangeable cations) were the main factors influencing the respective microbial structure. Bracken-invasion resulted in a decrease in the quantity and quality of aboveand belowground biomass. The lower organic substance and nutrient availability induced a significant decline in microbial biomass and activity. After pasture abandonment, these differences in soil microbial function were not accompanied by pronounced shifts in the community structure and in soil pH as was shown for the conversion to pasture. A disconnection between microbial structure and function was identified. Similar soil CO2–C effluxes between active and abandoned pasture sites might be explained by an underestimation of the effluxes from the active pasture site. All measurements were carried out between grass tussocks where fine-root density was about 2.6 times lower than below tussocks. Thus, lower proportions of root respiration were expected than below tussocks. Overall, soil microorganisms responded differently to changes in land-use from forest to pasture and from pasture to abandoned pasture resulting in pronounced changes of carbon and nutrient cycling and hence of ecosystem functioning.

Abstract:

In this issue 14 working groups from several scientific disciplines provide an insight into their latest research results uncovered in the diverse ecosystem of the tropical mountain rainforest. The Tumbesian dry forest is introduced and hints at success and moving of people from the Research Unit are given.

Abstract:

The 8th TMF Newsletter informs about: Visiting DFG officials, the new structure during the second phase of the Research Unit, NCI proposes a bioknowledge program, new mycobiotns of orchids discovered, cooperation with scientists from EDIT who explore ants, beetles and flies in the RBSF area and amongst others data warehouse news as well as new people and staff members.

Abstract:

Five groups of the Research Unit (RU) report about their latest results: the transformation of nitrogen, mycorrhizas and reforestation, land use and erosion, modelling and remote sensing and mycorrhizas in seedling development. The ninth TMF Newsletter also summarizes news around the research station, new DFG-cooperation projects, and describes why the RU can be viewed as a model to update the Access and Benefit-Sharing (ABS) protocols of the Convention on Biological Biodiversity (CBD). New cooperation partners from the ABA ECUADOR initiative are about to start field work. And a project plan is introduced to overcome ecological and institutional barriers for restoration of biodiversity and forest utilization potentials.

Abstract:

The tenth TMF Newsletter summarizes what's new at the approaching Symposium of the Research Unit (RU). It describes how the research permits for the study area in Ecuador may be influenced by the upcoming CBD conference in Nagoya, Japan. NCI informs about a 1.5 Million fund for conservation and bioknowledge. One research group illuminates the competition between bracken fern and Setaria grass. Another group calculated the price which may be able to prevent further deforestation. And the warehouse managers explain how the RU's database is interrelated with databases from other ecologists and the World Wide Web.

Abstract:

The tasks and challenges of the RU in 2011, a summary of the successes of the last year and the visit at a feasible new research site are among the topics. Others cover the fire that destroyed the reforestation plots, science news about precipitation and nutrient availability, effects of transformations from forests to pastures on soils as well as ?canopy wetlands? as a novel source of methane. The web-based planning tool ?MapViewer? is introduced. News about cooperating partners as well as new people and staff members round off the 11th issue of the TMF-Newsletter.

Abstract:

A delegation of the Germany Science Foundation (DFG) visited our RU and met people and organizations to take the next steps towards the new Research Platform to monitor global change. News in the science section offer insights into fungi inventories, mycorrhiza communities and bracken compositions, long term climate measurements, pollen rain calibrations, and into the evolution of moths megadiversity, which took place much earlier than previously supposed. One partner from EDIT reports that for some ants habitat may be more important than food. Further topics are how FOR816 datasets should be cited, new members of the RU and an exhibition in which research results of the RU will be displayed in several places in Germany.

Abstract:

Speakers' Corner ............................................... 1 Preparing Book, Papers, and new Research Platform .... 1 Upcoming Events.............................................................. 4 News from the ECSF ......................................... 4 High ranking Delegation at the Research Station ............. 4 Visit from GIZ Ecuador ..................................................... 4 Closing of the Airport of Loja............................................. 4 News from NCI .................................................. 5 Creating a Cajas Biosphere Reserve ............................... 5 Conserving the Ecuadorian Amazon ................................ 6 Science News .................................................... 7 Fate of Epiphytes on Remnant Trees ............................... 7 Different Disturbance Regimes & Forest Dynamics ....... 8 NUMEX: Nutrients and Regeneration of Forest Trees ..... 9 NUMEX: Tree Growth Along Gradients ..........................10 Ways of Water in the Ground ..........................................12 Biomarkers for Organ ic Carbon Sequestration ...............13 Cooperations .................................................. 14 UTPL: A Network for Research and Monitoring ..............14 EDIT: Experimental Draught Effects Ant Assemblage ...15 Data Warehouse News .................................... 16 Miscellaneous .................................................. 17 Ecuador goes Tanzania ..................................................17 People & Staff .................................................. 17 Event Calendar ............................................... 18 Deadline .......................................................... 18 Credits & Contact ............................................ 18

Abstract:

Landslides are a common phenomenon within the Ecuadorian Andes and have an impact on soil-landscape formation. Landslide susceptibility was determined in a steep mountain forest region in Southern Ecuador. Soil mechanical and hydrological properties in addition to terrain steepness were hypothesised to be the major factors in causing soil slides. Hence, the factor of safety (FS) was calculated as the soil shear ratio that is necessary to maintain the critical state equilibrium on a potential sliding surface. Regression tree (RT) and Random Forest (RF) models were compared in their predictive force to regionalise the depth of the failure plane and soil bulk density based on terrain parameters. The depth of the failure plane was assumed at the lower boundary of the stagnic soil layer or soil depth respectively, depending on soils being stagnic or nonstagnic. FS was determined in dependence of soil wetness referring to 0.001, 0.01, 0.1 and 3 mm h&#8722;1 net rainfall rates. Sites with FS&#8805;1 at 3 mm h&#8722;1 (complete saturation) were classified as unconditionally stable; sites with FSb1 at 0.001 mm h&#8722;1 as unconditionally unstable. Bulk density and the depth of the failure plane were regionalised with RF which performed better than RT. Terrain parameters explained the spatial distribution of soil bulk density and the depth of the failure plane only to a relatively small extent which is reasonable due to frequent translocation of soil material by landslides. Nevertheless, their prediction uncertainty still allowed for a reasonable prediction of nconditionally unstable sites.

Abstract:

In this paper, the central Pacific cold event of 2008 and its exceptionally warm conditions in the eastern tropical Pacific are analyzed by using rainfall data of south Ecuadorian meteorological stations, sea surface temperatures in the El Niño3 and 1+2 regions, and simulations with the Weather Research and Forecasting (WRF) model. It can be shown that El Niño-like rainfall conditions with severe inundations occur particularly in the coastal plains of southern Ecuador while a central Pacific cold event prevails. In contrary to previous situations, positive rainfall anomalies as a result of El Niño-like conditions in the El Niño1+2 region during the 2008 La Niña event occurred in both regions, the coastal plains and the highlands, for the first time. A detailed analysis of the ocean-atmosphere system during episodes of heavy rainfall reveals typical El Niño circulation and rainfall patterns as observed during previous El Niño events for the coastal area and La Niña-like conditions for the highlands. The spreading of Pacific instability in the Niño1+2 region to the eastern escarpment of the Andes could be the result of a temporary eastward shift of the Walker circulation. The unusual combination of El Niño-like conditions in the eastern tropical Pacific during a La Niña state in the central Pacific is the newest indicator for an impact mode shift regarding severe rainfall anomalies during El Niño/La Niña events in the traditional El Niño area of southern Ecuador since the end of the last century. Since 2000, El Niño events unexpectedly provide below average rainfall while central Pacific La Niña conditions generate exceptional severe flooding in the normally drier coastal plains. The novel sea surface temperature (SST) anomaly dipole structure between the eastern and central/western tropical Pacific and the weakening of El Niño events since 2000 could be due to natural decadal oscillations in the El Niño background state, the Pacific Decadal Oscillation (PDO). However, the observed atmospheric patterns and the recent increase of the SST anomaly difference between the central and the eastern tropical Pacific resemble structures that also result from climate change simulations.

Abstract:

Forschungsdateninfrastrukturen unterstützen den Austausch und die Speicherung von wissenschaftlichen (Primär-)daten. Durch die Beschreibung der Daten (Metadaten), können die Informationen vernetzt und für andere Wissenschaftler zugänglich und nutzbar gemacht werden. Neue und verknüpfende Interpretationen der Informationen führen zu neuen Erkenntnissen und Wissen, ohne eine erneute zeit- und kosten-intensive Datenaufnahme durchzuführen. Synergieeffekte ergeben sich und das Poten-tial der Daten kann besser ausgeschöpft werden. Dies gilt sowohl für den Datenaus-tausch in organisatorisch begrenzten wissenschaftlichen Projektgruppen, als auch für den Zugriff auf öffentliche fachspezifische Langzeitarchive, wie sie von Forschungsträ-gern wie der Deutschen Forschungsgemeinschaft (DFG) und von Verlagshäusern wissenschaftlicher Literatur angeboten werden. Durch die Einrichtung standardisierter Schnittstellen können globale Zugriffe über das Internet auf verschiedene Datenbestände ermöglicht werden. Für die verteilte Nutzung von Daten mit Raumbezug (Geodaten) hat das Open Geo-spatial Consortium (OGC) eine Reihen von Spezifikationen erarbeitet und frei zugäng-lich veröffentlicht, welche die standardisierte Bereitstellung von Geodaten über Web Services ermöglichen. Diese Arbeit zeigt Potentiale und Grenzen der Nutzung von OGC Web Services für den Einsatz in Forschungsdateninfrastrukturen beispielhaft an der technischen Infrastruktur und dem Datenbestand der geoökologischen Forschergruppe FOR816 auf. Bei der Evaluierung der Einsatzmöglichkeiten der OGC Web Services bzw. deren Imp-lementierung in Softwareprodukte, standen Nutzeranforderungen und die praktische Realisierbarkeit im Fokus. Da ein Großteil der Nutzergruppe keine vertieften Kenntnis-se in dem technischen Umgang mit Geodaten hat, soll der Zugang zu entsprechenden Daten aus dem Datenbestand möglichst einfach über browserbasierte Applikationen erfolgen. Als Bedarf wurden zwei Anwendungsbereiche ermittelt: i) Eine Kartenanwen-dung, die durch geeignete Layer eine Orientierung im Untersuchungsgebiet sowie das Abgreifen und Darstellen von Koordinaten erlaubt. ii) Ein Analysetool zur punktuellen Extraktion und Auswertung von Werten aus raumzeitlichen Rasterdatenbeständen. Konkret soll eine mehrjährige Zeitreihe von flächenhaft vorliegenden Stundenniederschlagssummen durch räumliche und zeitliche Selektion zugänglich gemacht werden. Die OGC Web Services werden hierbei als gut dokumentierte, standardisierte Dienste zur serverseitigen Datenaufbereitung eingesetzt, um den Ansprüchen an wissenschaftliches Arbeiten bezüglich der Nachvollziehbarkeit Rechnung zu tragen. Sie dienen in dieser Systemarchitektur nicht der unmittelbaren Bereitstellung der Geodaten für externe Clients, sondern werden zunächst als Werkzeuge, welche die Schwierigkeiten des räumlichen (und zeitlichen) Subsettings und Resamplings beherrschen, für die Entwicklung der nutzerkreisspezifischen, serverseitigen Applikationen eingesetzt. Die Kartenanwendung wird durch den Einsatz eines Web Map Services (WMS) in Ver-bindung mit einem browserbasierten Client (OpenLayers) realisiert. Für die Realisierung der raumzeitlichen Analyse bieten sich verschieden OGC Standards mit unterschiedlichem Funktionsumfang an. Der Web Coverage Processing Service (WCPS) bietet die räumliche und zeitliche Selektion, sowie die serverseitige Prozessierung der Auswahl. Der Web Coverage Service (WCS) Standard definiert ein räumliches und zeitliches Subsetting. Für die Realisierung der raumzeitlichen Analyse wurden der Web Coverage Processing Service (WCPS), der Web Coverage Service (WCS) und der WMS mit der Operation GetFeatureInfo in Betracht gezogen. Auch wenn die Spezifikationen einen passenden Funktionsumfang definieren, so hat sich in der praktischen Anwendung gezeigt, dass die verfügbaren Softwareprodukte, die diese Services implementiert haben, noch nicht alle (optionalen) Funktionen der Dienste anbieten. Für den WCPS und den WCS gibt es kein Softwareprodukt, welches die Verarbeitung von Zeitinformationen ausreichend unterstützt. Daher wird zusätzlich der Einsatz eines WMS und eine Umsetzung der Anforderungen ohne den Einsatz eines OGC Services vorgestellt und diskutiert. Als Ergebnis können funktionsfähige Lösungen präsentiert werden.

Abstract:

Neotropical Vaccinioideae (Ericaceae) are evolutionary rather young and presumably of Northern Hemisphere origin. Vaccinioideae are highly dependent on their mycorrhizal symbionts and Sebacinales (basidiomycetes) were previously found to be the dominant mycobionts of Andean Clade Vaccinioideae (Neotropical Vaccinieae). We were interested to see whether the North American Vaccinioideae reached the Neotropics with their mycobionts or whether they acquired new, local Sebacinales. We investigated Sebacinales of 58 individuals of Vaccinioideae from Ecuador, Panama and North America to examine whether mycobionts of each region are distantly or closely related. We isolated the ITS of the ribosomal nuclear DNA in order to infer a molecular phylogeny of Sebacinales and to determine Molecular Operational Taxonomic Units (MOTUs). MOTU delimitation was based on a 3% threshold of ITS variability and conducted with complete linkage clustering. The analyses revealed that most Sebacinales from Ecuador, Panama and North America are closely related and that two MOTUs out of 33 have a distribution ranging from the Neotropics to the Pacific Northwest of North America. The data suggest that Neotropical and temperate Vaccinioideae of North America share their Sebacinales communities and that plants and fungi migrated together.

Abstract:

Aerial photographs of the Cotopaxi Volcano ice cap dating from 1956 to 1997 were used to quantify the evolution of the surface area. Results were obtained using precise stereoscopic methods that give the most accurate information. In addition four specific glacier tongues were investigated in detail to measure the ice mass lost between 1976 and 1997. Surprisingly, the bedrock morphology is shown to be very irregular and this explains a large extent of the variability found in the ice losses. The results show that glaciers stagnated from 1956 to 1976 and lost about 30% of their surface area between 1976 and 1997. Slope exposure did not seem to have any significant effect since all the glaciers of the volcano retreated in the same proportion. In accordance with specific measurements performed on the nearby Antizana 15 Glaciers, it is suggested that the strong recession observed after 1976 was associated with increasing melting conditions which have occurred repeatedly during the intense/long-duration warm ENSO phases. Key words: climatic change; Cotopaxi Volcano; Ecuador; glacier retreat; photogrammetry; South America

Abstract:

During the last decades a need for more agricultural land was to be recognized in Ecuador. Reasons for this need were a rapidly growing population and a non sustainable use of land which caused degradation and abandonment of large territories. As a result labile ecosystems like the Ecuadorian montane rain forest were anthropogenically disturbed and cultivated. The aim of this study was to investigate the effect of anthropogenic disturbances on landscape structure and to describe the actually existing mosaic of disturbed and undisturbed patches. Another intention was to identify the driving forces of landscape structure and its dynamics. A 25 km long and 4 km wide area in the south of the Ecuadorian Andes was choosen as study site. Altitude ranges from 1050 to 2600 m above sea level and can be regarded as a location where naturally a montane cloud forest would be growing. The land use of the complete area was mapped firstly. To gain a deeper insight into land use practices and techniques, 12 farms were selected and investigated more intensively. Maps were drawn of every farm by viewing the patches from the other side of the valley. Where a rapid change in land use was recognized, boundaries were marked. Afterwards every patch was examined and data on position within the landscape, structure and cultivation were recorded. Following interviews with each owner served for gaining more knowledge about land use practices and the socio economical background of the family. During investigation of the patches two different scales were taken into consideration: the scale of the stand and the landscape scale, respectively. Based on the parameters which referred to the stand a cluster analysis was applied to all the patches. It resulted in the distinction of 14 structural patch types which then were interrelated with different landscape parameters. The landscape of the region is very heterogeneous and rich in structural elements. The primary forest which once covered all of the area was cultivated and changed into cropland and mainly pasture. Although it is now pushed back on sites which are unfavourable for agriculture, the forest still builds the matrix for the embedded fields. The patches have different persistences and also differ in form and size. By comparing all farms one can recognize that there is a regularity in the arrangement of the different structural units. Based on the collected data and maps a scheme was drawn which shows this regular arrangement. Another scheme, which elucidates the temporal sequence between different patch types, was developed by comparing the information of the farmers with field-hints indicating former land use. Due to the low level of mechanization agriculture of the study site is still being very traditional. The extreme inclinations as well as the very low income rate of the farmers do not allow to buy machines which could facilitate the distinct working operations. Rather irregularly than geometrically shaped patch forms and rather gradual than distinct boundaries are the result. Some of the farmers are using fire to clear the forest or the already existing pastures, which causes a rapid decline of nutrients during the following weeks. Undemanding species like bracken (Pteridium aquilinum (L.) Kuhn) are now able to invade the fields and compete with crops and pasture for left nutrients. Clearing even extremely inclined slopes and thereby causing soil erosion increases the effect of degradation. Because of not using fertilizers or taking measures against soil erosion the farmer is compelled to abandon degraded and unproductive sites and replace them by clearing more forest. As a consequence the loss of montane cloud forest continues. To oppose this prospect a modification of non sustainable land use practices regarding the needs and knowledge of the Ecuadorian population has to be implemented. More scientific investigation could contribute to this aim.