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

Abstract:

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.

Abstract:

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.

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.

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.

Abstract:

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

Abstract:

The speakers give a glimpse on the complex on-site review procedure of the projects which constitute the German part of the new Platform for Biodiversity and Ecosystem Monitoring and Research in South Ecuador. They also report about the Status Symposium which enjoyed a numerous audience. NCI reports about the application to the UNESCO for the first biosphere reserve in the Ecuadorian Western Cordillera comprising the entire ecological gradient from the Paramo to the Pacific. The Science News present an investigation of the famers’ preferences of land use options for the recultivation of abandoned agricultural areas. An analysis of nitrogen fixation shows why nutrient budgets should include the canopy. The data manager and the webmaster analyze the usage of the RU’s data warehouse.

Abstract:

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.

Abstract:

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

Abstract:

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.

Abstract:

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.

Abstract:

In the mountain rainforest region of southern Ecuador, soils of active pastures, established after slashand- burn of the forest, are characterized by improved quantity and quality of soil organic matter favoring microbial conditions. However, these beneficial conditions decrease with increasing pasture age and burning frequency. As a consequence, rates of soil nutrient cycling decrease, supporting the infestation of bracken fern and, in turn, causing further decreases in pasture productivity. Finally, farmers are forced to abandon the degraded pastures and to establish new ones by continuous deforestation. To investigate whether an application of N and/or P nutrients to an extensively grazed pasture (active pasture) can improve grass productivity and maintain soil fertility, a pasture fertilization experiment was conducted. On an active pasture site, planted with Setaria sphacelata, moderate rates of urea (50 kg N ha&#8722;1 a&#8722;1), rock phosphate (10 kg P ha&#8722;1 a&#8722;1), and a combination of both were applied. It was examined whether soil mineralization (gross and net N mineralization, SOC mineralization) and microbial community structure (PLFA-analysis), as well as quantity and quality of the grass biomass, were affected by fertilization. Furthermore, the impact of fertilization on in situ soil respiration rates was studied. The combined application of urea and rock phosphate increased the pasture yield by 2 Mg ha&#8722;1 a&#8722;1 most efficiently, indicating a co-limitation of growth. Additionally, the fodder quality was improved by a 67% higher content of P and by a 7% higher content of Ca in the grass biomass compared to the control. While carbon, nitrogen, and phosphorus in the microbial biomass remained unaffected and the microbial activity increased only temporarily, the relative abundance of fungi (18:2n6,9) increased significantly due to fertilizer addition. Urea addition induced a short-lived increase in the in situ soil CO2-C effluxes, assuming a positive priming effect due to an activation of soil microbes. In total, plots amended with urea emitted 0.8 Mg CO2- C ha&#8722;1 a&#8722;1 more than the control. Results reveal that already moderate fertilization significantly improved pasture productivity and maintained soil quality. However, it is expected that higher loads of NP fertilizer will increase pasture productivity at the expense of soil organic carbon sequestration due to enhanced soil CO2-C losses. Hence, to establish a sustainable pasture management in the study region, the soil C management must also be carefully considered.

Abstract:

Growing land scarcity due to population increase promotes the conversion of natural ecosystems into areas for food and energy production, especially in the tropics. On the other hand, high proportions of degraded land are present. In the research area in the south-eastern Andes of Ecuador about 40% of the potential pastureland has been abandoned because of infestation by bracken (Pteridium spp.). This rhizomatous plant is one of the most aggressive weeds worldwide especially where fire is used for forest clearing or in agriculture. Taxonomically, it represents a complex that is grouped into a northern, temperate, and a southern, tropical clade. In the research area, two species of the southern bracken complex, P. arachnoideum and P. caudatum, co-occur. We analysed the bracken species composition on active and abandoned pastures at 7 altitudinal levels between 1,000 and 3,000 m. The 2 species could be differentiated using morphological and molecular characters. Depending on the altitudinal and climate conditions, the shares of the two species in the bracken cover changed: P. caudatum preferred the lower altitudes, where P. arachnoideum was hardly found. The opposite was observed in the upper regions. At 1800 m an extensive study of the composition of the bracken population was performed using microsatellite markers. As bracken propagates readily via rhizome branching and disaggregation, a high degree of homogeneity of the ramets was expected. However, the percentage of identical ramets of both species was very low, as were distances at which genetically identical samples were found. Maximum extension of a genet (consisting of several ramets) was less than 150 m which contrasts with findings of northern bracken species. The high diversity was attributed to a high frequency of bushfires whose heat could stimulate sexual reproduction. After such fire fast colonization of the bare soil by bracken was observed. The entire developmental cycle from spore formation until ample growth of young sporophytes required less than 2 months. In addition, regrowth of bracken fronds from rhizomes was also stimulated by the heat pulse from such fires.

Abstract:

Deforestation for gaining pastures and croplands is still advancing in the tropical Andes while vast agricultural areas are at the same time disused due to degradation (FAO 2011). In the research area in South Ecuador infestation by bracken (Pteridium spp.) plays an important role in this regard (Göttlicher et al. 2009), especially where fire is used for forest clearing or in pasture management (Hartig & Beck 2003, Roos et al. 2010). The focus of our study was: (1) the analysis of the infestation rate of bracken on agricultural land, (2) to reconvert bracken-infested areas into useful pastures, and (3) to find a sustainable management for the rehabilitated pastures. Bracken cover was analyzed using high resolution satellite data (QuickBird) on which bracken could be identified from the spectral reflection. Actually, almost 40% of the potential mountain pastures in the research area have been abandoned, because they are overgrown by the weed. An experiment extending over several years was conducted to reconvert these abandoned areas into pastures (Roos et al. 2011): A two-step strategy seemed to be successful. In a first step, the efficacy of 13 bracken control treatments was compared with the vegetation development in untreated plots. Two of the measures proved to be successful and at the same time affordable for the local farmers, namely periodical cutting of the weed with a machete or repeated spraying of a locally available herbicide ?Combo? (a mixture of metsulfuron methyl and picloram) (Figure 1A). However, due to brackens persistent rhizomes in various soil depths, only ponderable weakening of the weed could be achieved, but not complete eradication. In a next step, the common pasture grass Setaria sphacelata (a highly competitive C4-grass) was planted. About 1.5 years later, the grass had reached a cover of more than 70% suppressing the fern to a cover of less than 40% and grazing could start (Figure 1B). Growth of bracken and of Setaria was monitored monthly using cover and height of vegetation as variables. Different extensive and intensive management treatments (various grazing intensities in combination with fertilization regimes) were applied to the rehabilitated pasture plots, and the effects on biomass gain and protein content of Setaria were analyzed. Additionally, vegetation composition depending on the treatments was compared with existing pastures. Regrowing bracken fronds should be removed annually with the machete to maintain the weed on a low stage. Following the described protocol, repasturisation requires about 2.5 years until the pastures can be used. Applying a balanced management of fertilization and grazing can lead into a sustainable reutilization of the abandoned areas and thus alleviate the pressure on the natural forests.

Abstract:

Im Arbeitsgebeit Q2 ist die anfallende Streufallmenge in der Periode April 2004 bis März 2005 im Vergleich zu anderen tropischen Bergregenwäldern hoch, im Vergleich zum langjährigen Mittelwert jedoch etwas geringer. Die wöchentlichen Streufallmengen zeigen grosse Unterschiede, welche vermutlich auf mechanische Belastungen zurückzuführen sind. Die Zinkgehalte in der Feinstreu sind geringer als vergleichbare Werte in der Literatur. Die Kupfergehalte in der Feinstreu sind geringer als die Zinkgehalte, vergleichbare Werte in der Literatur wurden keine gefunden. Die Deposition von Zink ist durch die geringeren Zinkgehalte in der Feinstreu und die etwas geringeren Streufallmengen ebenfalls geringer als vergleichbare Werte in der Literatur. Die Deposition von Kupfer ist analog zu den Gehalten in der Feinstreu geringer als die von Zink. Die Hypothese, dass die Elementeintröge vom Wasserhaushalt abhängen konnte nicht bestätigt werden. Die Zinkgehalte in der organischen Auflage entsprechen in etwa vergleichbaren Werten der Literatur. Die Kupfergehalte sind wiederum geringer als diejenigen von Zink. Auch hier fehlen Vergleichbare Werte aus der Literatur. Die Elementgehalte nehmen in der organischen Auflage mit zunehmendem Zersetzungsgrad zu. Diese Zunahme widerspiegelt sich ebenfalls im Speicher der Elemente in der organischen Auflage, obwohl hier auch die Mächtigkeit der Auflagehorizonte einen grossen Einfluss hat. Es kommt zu einer Anreicherung von Kupfer und in geringerem Masse auch von Zink in der organischen Auflage, was auf einen engen Kreislauf dieser Elemente im Ökosystem hindeutet. Die Umsetzungszeiten der Masse, von Zink und Kupfer sind insgesamt als hoch einzuschätzen. Vergleichbare Untersuchungen im selben Arbeitsgebiet ergaben niedrigere Werte und auch der Vergleich mit anderen tropischen Bergregenwäldern deutet darauf hin, dass die Umsetzung langsamer abläuft. Im Vergleich zu gemässigten Klimaten sind die Umsetzungszeiten jedoch geringer. Die Vernachlässigung der Einträge durch Grobstreu und Feinwurzeln führen allerdings zu einer beträchtlichen Überschätzung der Umsetzungszeiten.

Abstract:

One crucial aspect within most joint projects in ecosystem research is the way of data storage and exchange. The Data Warehouse of the DFG-Research Unit 816 (FOR816dw) provides an integrative platform to enable the retrieval, transfer, storage, and analysis of scientific data of various ecological disciplines, focused on biodiversity research. To structure the data and to make it usable by other scientists a robust metadata concept had to be implemented. The Ecological Metadata Language (EML: www.knb.ecoinformatics.org/software/eml) provides a sophisticated XML-based scheme to describe scientific ecological data sets. The relational database structure of the FOR816dw is based on the metadata logic of EML and contains at least all mandatory fields to be compliant to this specification. The metadata are transmitted by the data owner via a browser based wizard during the data upload. They can be queried for temporal, spatial, and thematically features to find data sets in the data pool. Furthermore the metadata bears information on the data set creator, the intellectual rights, and the data collection/processing workflow of each contained attribute of a data set. The adaption of the concept to describe each attribute (variable) of a data set establishes the granulated storage and analysis of the tabular data set values. All information are safely stored in the relational database and can be filtered, selected and reused. Beside the storage and maintenance of data sets and metadata the FOR816dw provides the management of administrative tasks of the research group. The user management, the project structure, a news system, a mailing-lists generator, the travel reimbursement, and the station booking system is based on the same personnel and project specific data used for the metadata description of the scientific data sets. The project`s webpage (www.tropicalmountainforest.org) is the single point of contact for the project members and provides a user-friendly access to all information of the DFG-Research Unit 816 ?Biodiversity and Sustainable Management of a Megadiverse Mountain Ecosystem in South Ecuador?. After six years of development and running, an open source release will be available at the termination of the FOR816 in March 2013. With this in view we want to review some technical and conceptual solutions and discuss the acceptance by the users. Is the representation of EML in a relational database possible? Is the combination of project administration and data management in one platform useful? Up to what level of detail are the users willing to submit and describe their data?

Abstract:

Ziel der Arbeit war es, die Mykorrhiza-Pilzpartner von G. harlingii molekular zu identifizieren und mit vorhandenen Sequenzdaten von G. emarginata und anderen Bäumen aus dem Untersuchungsgebiet zu vergleichen. Zum einen sollte dadurch überprüft werden, ob sich die AM-Pilzpartner von G. harlingii im Vergleich zu G. emarginata und anderen Bäumen aus dem Untersuchungsgebiet unterscheiden. Zum anderen sollte untersucht werden, ob neben G. emarginata auch G. harlingii eine Doppelmykorrhizierung mit arbuskulären Mykorrhizapilzen und einem Ascomyceten im Untersuchungsgebiet zeigt. Hierfür wurden auch lichtmikroskopische Unter-suchungen durchgeführt.

Abstract:

Land-use and land-cover changes (LULCC) affect local climate. Human-induced defor-estation is a common phenomenon of LULCC. This also holds true for the biodiversity hotspot in the Andes of Ecuador. This study assesses the possibility to project LULCC to future time steps with a focus on deforestation in the San Francisco valley in South Ecuador. A business-as-usual scenario based on two Landsat scenes from 1987 and 2001 was created to project LULCC until 2006. The uncertainty assessment indicated the difficulty of projecting human impact on the ecosystem since circumstances of LULCC in the study area cannot be assumed to stay invariant. The projection performs better than a naive model relying on slope as its suitability factor.

Abstract:

During the Quaternary, in particular during glacial times, different grassland ecosystems played a much larger role and had a significantly larger distribution. Little is known yet about past development, biodiversity and dynamics of grassland ecosystems. In this innovative study, we attempt to distinguish between different South American grassland types in space and time based on morphological pollen grain characteristics of Poaceae. For this purpose[60?80 Poaceae pollen grains of 20 grassland samples were measured using their length, width and pore diameter as well as annulus width. Samples were taken from five sites in wet Pa´ramo vegetation from the Late Pleistocene to the Late Holocene in South Ecuador and from two sites in the south-eastern Brazilian highlands (Campos do Altitude) of the same period. Additionally, we investigated two samples from a Pampa site as well as six samples from one Campos grassland site in southern Brazil from the Late Pleistocene to the Late Holocene. Subsets of samples of the Campos grasslands and of the Pa´ramo were investigated in order to retrieve more detailed information on patterns within these vegetation types. Multivariate data analysis of the complete data set shows changes in taxonomic composition along an elevational gradient in the Pa´ramo grasslands. Our results reveal a highly dynamic development of the individual grassland types; they also provide interesting information on Poaceae taxa composition patterns, development and possibly changes in biodiversity within these ecosystems. Moreover, our data provide an indication about the origin and dynamics of the Campos ecosystems in the southern Brazilian highlands during the Late Pleistocene and the Holocene before and after the onset of human activities.

Abstract:

Despite the dominance of grasslands during the last glacial period, especially in South America, the highly uniform morphology of Poaceae pollen grains has so far allowed only very few palynological studies based on Poaceae pollen. In our study we compare two methods of distinguishing between South American grassland ecosystems based on quantitative morphology of Poaceae pollen grains. We investigated data sets from Pa´ramo in southern Ecuador, Campos de Altitude and Campos in south-eastern and southern Brazil as well as data sets from the Pampa in Argentina by measuring the pollen grain length, grain width, pore diameter and annulus width. Firstly we investigated the potential influence of chemical treatment of pollen grains on pollen grain size as well as the measurement setting for defining the boundary conditions for using Poaceae pollen grains in a palaeoecological investigation. Finally the measured pollen grain parameters were analyzed by comparison of average grain length using statistical tests. This approach reveals highly significant differences in average grain size between all grassland ecosystems. Assuming that a certain grain size range can be assigned to a certain Poaceae taxon, conclusions about differences and similarities in taxa composition can be derived. We used two methods of multivariate data analysis. One uses the pollen grain parameters directly for a Principle Component Analysis (PCA). The other is an already established method in grassland ecology which defines parameter based pollen grain types to investigate similarities between grassland ecosystems. Both approaches confirm the results of the grain length analysis. In this work we demonstrate that the method we developed has the potential to provide acquisition of so far inaccessible information on spatial and temporal patterns and dynamics of South American grasslands.

Abstract:

We reconstructed the palaeoenvironmental conditions of the last ca. 8000 years in the Tres Lagunas region of the Quimsacocha volcanic basin (ca. 3800 m a.s.l.) in the southwestern Ecuadorian Andes by means of a pollen and charcoal record. Sediment deposits and pollen taxa reflect warm and possibly drier conditions in the early to mid-Holocene. The late Holocene undergoes several warm and cold-phases of which the most prominent one was the Little Ice-Age which is characterised by a marked increase of taxa that correspond to cold and moist conditions. As charcoal can be recorded since the early to mid-Holocene and Polylepis underwent several phases of degradation and re-establishment in the region, the presence of human influence might be dated back to this time.

Abstract:

The vegetation,climate and fire history of high mountain ecosystemsin the southern Ecuadorian Andes are documented in a continuous pollen and charcoal record,from Lagunas Natosas Forest bog,at 3495 m a.s.l. spanning the late Pleistocene and Holocene periods since 15,930 cal yr BP.The chronology of this record is based on four radiocarbon dates.Páramo vegetation with abundant Poaceae and Plantago rigida characterized the Late Glacial(LG)period, implying cold and wet conditions. Slight expansions of mountain forests suggest warming during the LG. The upper foresl line was lower than today and &#64257;re events were rare during the Pleistocene. During the early and mid-Holocene until 4300 cal yr BP, the area of páramo was markedly smaller and the subpáramo with woody vegetation (Melastomataceae) was larger. The upper mountain forest dominated and the upper forest line shifted to higher elevations. The pollen record provides the first evidence of the development of Polylepis forests in the southern part of the so-called Andean Depression reflecting warmer and drier climatic conditions during early and mid-Holocene. The late Holocene after about 4300 cal yr BP is characterized by larger areas of páramo and subpáramo promoted by moister conditions. These moister conditions and frequent fires may have been the cause of the very rare occurrence or even extinction of Polylepis populations in the Jimbura region. Since ca. 1000 cal yr BP human occupation has altered the landscape by frequent burning, woodcutting, grazing and cultivation.