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

Abstract:

Based on 5 pollen records from locations between ca. 2700 and 3300 masl in the Podocarpus National Park (PNP) area (ca. 4° S and 79° W) within the Andean depression region in southern Ecuador, we reconstructed and visualized upper forest line (UFL) dynamics and past vegetation changes since the last glacial maximum (LGM). Estimates of altitudinal ranges of past UFL shifts in the study area allowed reconstructing past changes of forest and páramo expansion in the study region. During the LGM, the UFL position in the PNP area was at least ca. 700 m lower in the northernmost part and ca. 250 m further south compared to today. Glaciers covered the central PNP at this time, while deglaciation completed with the beginning of the Holocene. Throughout the recorded time UFL shifts and vegetation changes in the study area showed considerable local differences. This can be explained by locally differing vegetation compositions and climatic conditions, but especially during early to late Holocene times also by human disturbances. Only during the earliest Holocene and mid-Holocene the UFL in the central and southern PNP areas reached slightly higher elevations up to 200 m above the present position. The UFL in the PNP area shifted altitudinally over a shorter interval compared to other sites outside the depression. This difference may be caused by the study regions relatively low mountain elevations, wet climatic conditions, different and diverse vegetation pattern as well as by the corresponding vegetation response to climatic changes. The high complexity and heterogeneity of Andean habitats are assumed to be responsible for the variety in altitudinal distribution and compositional changes of vegetation. In the PNP area and the Andean depression region temperature seems to be less important for the UFL and vegetation changes than in other regions of the northern Andes. Instead we assume that other drivers, e.g. precipitation and wind, may be much more important for the developments in our study region.

Abstract:

Die Bergregenwälder Südecuadors zählen zu den ?Biodiversitätshotspots? der Erde, sind jedoch gleichzeitig durch Abholzung in Gefahr, ihre ökosystemaren Funktionen zu verlieren. Hinzu kommt anthropogen verursachter, externer Stress, wie erhöhte Nährstoffeinträge, von denen erwartet wird, dass sie in den nächsten Jahren weiter zunehmen. Um deren Einfluss auf einen nährstoffarmen Bergregenwald in Südecuador zu untersuchen, wird in einem manipulativen Nährstoffexperiment (NUMEX) die bis zum Jahr 2050 erwartete jährliche Depositionsmenge von 50 kg ha-1 a-1 N, 10 kg ha-1 a-1 P sowie 10 kg ha-1 a-1 Ca manuell in den Wald eingebracht (N-, P-, N&P, Ca- und Kontrollplots in einem randomisierten Blockdesign). Für meine Arbeit habe ich für einen Zeitraum von vier Monaten (Ende April 2009 bis Ende August 2009), in dem die vierte der halbjährlichen Düngungen lag (Mitte Juli 2009) die Nährstoffkonzentrationen (o-PO4 3-, Pges, NO3 -, NH4 +, Nges, DON, K, Na, Mg, Ca, pH-Wert) im Freiland- (FN) und Bestandesniederschlag (BN) sowie im Streuperkolat (SP) und der Mineralbodenlösung (BL) in 0,15 und 0,3 m Tiefe bestimmt. Zusätzlich habe ich die Nährstoffflüsse im FN und BN sowie eine Kronenraumbilanz nach dem Modell von Ulrich (1983) berechnet. Mein Ziel war es, die verschiedenen Varianten mit der Kontrolle hinsichtlich ihrer Nährstoffkonzentrationen und ?flüsse zu vergleichen und eventuelle Effekte der vierten Düngung auf diese heraus zu arbeiten. Stark erhöhte Konzentrationen einiger Elemente (o-PO4 3-, Pges, NH4 +, Nges, DON) im FN im Zeitraum vor der Düngung, die sich zum Teil auch in den verschiedenen Kompartimenten des Waldes wiederfanden, überlagerten die Düngeeffekte. Einzig die NO3 --Konzentrationen im BN der N&P-Plots lagen in diesen Zeitraum beinahe signifikant über denjenigen der Kontrollplots (p = 0,072). Signifikante Unterschiede der mittleren Konzentrationen im SP zur Kontrollvariante gab es für die N-Plots (NO3 - -Konzentration, p = 0,020 bzw. 0,023 vor bzw. nach Düngung). Insgesamt lagen die mittleren Konzentrationen der gedüngten Elemente in der BL der jeweiligen Versuchsplots nicht signifikant höher als in den ungedüngten Kontrollplots. Sie wiesen jedoch durchgehend einen Trend zu leicht erhöhten Konzentrationen auf. Durch die Düngung mit NaH2PO4 und CaCl2 traten Nebeneffekte auf. Die mittleren Na-Konzentrationen in der BL, sowohl der P- als auch der N&P-Plots, unterschieden sich vor und nach Düngung signifikant von denen der Kontrolle. Die mittleren Cl--Konzentrationen im SP der Ca-Plots lagen im Zeitraum nach Düngung signifikant höher als die der Kontrolle. Die Düngung mit N, P und N&P führte zu einer verminderten Retention von Nges (N- und N&P-Plots) und Pges (P- und N&P-Plots) im Kronenraum und damit zu erhöhten Flüssen im Bestandesniederschlag. Die Kronenraum-Bilanz für Ca wurde durch Ca-Düngung positiver, es kam also zu einer verminderten Retention im Kronenraum, während durch N-, P- und N&P-Düngung eine verstärkte Retention zu beobachten war. Meine Ergebnisse bestätigen, dass nur wenig des eingebrachten Düngers die mächtige organische Auflage bis hin zum Mineralboden passiert, die Nährstoffe also im System zurückgehalten und aufgenommen werden. Direkte Effekte durch die vierte Düngung sind jedoch nur teilweise in den mittleren Konzentrationen nachweisbar, wahrscheinlich, weil der Zeitraum für die Probenahme nach Düngerapplikation zu kurz gewählt wurde oder die Düngung mit einer so geringen Menge zu nur wenig ausgeprägten Unterschieden führt.

Abstract:

Eois is a pantropical genus of Geometridae moths with currently 250 valid described species, the majority of which occur in the Neotropics. Eois is a prominent component of Andean moth communities locally accounting for up to ca. 10% of geometrid individuals. We address the evolution of wing patterns and host plant use in Neotropical Eois and provide a preliminary assessment on the monophyly and biogeographic history of the entire genus as well as affinities within the subfamily Larentiinae. We applied Bayesian, maximum likelihood and maximum parsimony methods of phylogenetic reconstruction to a 142 taxon dataset of partial COI (1220 bp) and Ef1a (1066 bp) sequences resulting in the largest taxon set of geometrid moths analyzed in a molecular phylogenetic study so far. Monophyly of Eois was always strongly supported. Ten monophyletic clades were found with good support, seven of which have characteristic wing pattern phenotypes. Only one wing pattern type occurs in two clades. Trophic associations with representatives of the family Piperaceae occur in all 8 (of 9) Neotropical clades for which host information is available. Apart from feeding on Piper, at least two Eois species in Ecuador feed on Peperomia, and one on Manekia (all Piperaceae); two further species live on Hedyosmum (Chloranthaceae). Species feeding on Peperomia, Manekia and Hedyosmum are usually nested in Piper-associated clades. Single records of associations with Gesneriaceae and Monimiaceae are scattered in otherwise Piperaceae-associated clades. These patterns suggest multiple parallel host shifts away from Piper as ancestral food plant. Old World Eois were recovered as monophylum and sister to Neotropical Eois. Within the subfamily Larentiinae the genus Eois has previously been placed close to the tribe Eupitheciini, but this was not supported in our phylogenetic analyses.

Abstract:

La investigación se desarrolló con el propósito de disponer información sobre el efecto de las aplicaciones de N, P y Ca en el bosque sobre la lixiviación de cationes básicos (Ca++, Mg2+, K+, Na+) N y P, desde las capas orgánica y mineral (0,15 y 0,30 m) del suelo del bosque de la ECSF (al sur del Ecuador a 2 000 m.s.n.m.); y, su correspondencia con el incremento futuro de estos elementos en la atmósfera, como consecuencia de las emanaciones de las industrias, la volatilización desde el suelo por la aplicación de fertilizantes y el fenómeno de la Niña. Cuatro replicas en un bosque nativo fueron fertilizadas con 50 kg N.ha-1. año-1, 10 kg P.ha-1. año-1, la combinación de N/P y 10 kg Ca.ha-1. año-1 con urea 46% N, NaH2PO4.2H2O y CaCl2.2H2O, respectivamente. Cada muestra de agua colectada de las tres capas se realizo cada 15 días, se determino la concentración (mg/l) de Cl-, NH4+- N, NO3- - N, PO43- - P,Fósforo total, Nitrógeno total, Nitrógeno orgánico soluble (NO), K+, Na+, Mg2+, Ca2+y Carbono orgánico total. Tres meses después de la primera fertilización se registro un incremento de las concentraciones Cl- en el agua lixiviada de las capas orgánica y mineral (0, 15 y 0,30 m) en el tratamiento +Ca, atribuida al fertilizante aplicado (CaCl2). La ausencia de incrementos significativos de N, P y Ca en el agua lixiviada de las capas minerales llevan a asumir que las aplicaciones han sido retenidas en la capa orgánica y tomadas tanto por los microorganismos, como por las raíces de las plantas. El incremento significativo (p>0,05) en las concentraciones de K+ y Mg 2+ en la capa orgánica en el tratamiento +N+P y los tratamientos +N, +N+P y +Ca respectivamente, se atribuye a procesos de mineralización de la materia orgánica. El incremento del Na+ en las concentraciones del agua lixiviada de la capa orgánica en el tratamiento +N+P, se atribuye a la composición química del fertilizante aplicado (NaH2PO4). Los incrementos de las concentraciones de Ca2+ en el tratamiento +Ca sólo en el agua lixiviada de la capa orgánica se atribuye a la composición del fertilizante aplicado (CaCl2). La adición de Ca tuvo un positivo efecto en las concentraciones de carbono orgánico total (COT) en el agua lixiviada de la capa mineral (0,30 m) en el tratamiento +Ca. La ausencia de incrementos significativos de Na+, Ca2+ y Mg2+ en el agua lixiviada de las capas minerales (0,15 y 0,30 m) conduce a señalar que estos cationes fueron retenidos en el complejo de intercambio. En el testigo, las concentraciones promedio de Cl- (capa 0,30 m), PO4 3- , P total y Na+ (capas 0,15 y 0,30 m); y, NO y Nt (capa orgánica), fueron similares a aquellas reportadas por otros autores en el mismo bosque; las concentraciones promedio de Cl, NO - y NH4+ (capa orgánica y mineral 0,15 m); PO43- , P total, y K+ (capa orgánica); NO y Nt (capa 0,15 m); Mg2+, Ca2+ y COT en las tres capas fueron menores a las reportadas por otros autores en el mismo bosque; y, las concentraciones promedio Na (capa orgánica); y, K+ (capas 0,15 y 0,30 m) fueron mayores a las reportadas por otros autores en el mismo bosque.

Abstract:

En el Bosque de la Estación Científica San Francisco (ECSF) a una altitud de 2 000 m s.n.m. y como parte del proyecto NUMEX (experimento de manipulación de nutrientes), se realizó un estudio para conocer el efecto de la aplicación de N, P y Ca al suelo, con el propósito de disponer de información del efecto sobre las concentraciones de cationes básicos (Ca++, Mg++, K+, Na+), y del N y P, en la lluvia que atraviesa el dosel y en la hojarasca. Se realizaron colectas cada quince días y cada mes respectivamente, usando colectores de lluvia y canastillas para posteriormente ser analizadas mediante Espectrofotometría de Absorción Atómica para el K+, Na+, Mg++, Ca++, el Analizador Elemental para el carbono orgánico, y el Analizador de Flujo Continuo para el PO43-, Cl-, NH4+, NO3-, Fósforo total y Nitrógeno total. Obteniéndose como resultado que las concentraciones de cloro, ortofosfato, fósforo total, nitrato, y sodio no fueron estadísticamente significativas; el tratamiento +N fue significativamente mayor en las concentraciones de amonio y nitrógeno total, pero tuvo las concentraciones más bajas de magnesio y calcio; el tratamiento +N+P fue significativamente mayor en la concentración de nitrógeno orgánico soluble y potasio, y el testigo fue significativamente mayor en la concentración de carbono orgánico total en el agua de lluvia que atraviesa el dosel. Por otro lado la cantidad de hojarasca disminuyó después de la fertilización, por tanto las concentraciones de carbono, nitrógeno, fósforo, calcio, magnesio, potasio y sodio en la hojarasca no fueron significativas (p<0,01) para los diferentes tratamientos, y todos sus cantidades fueron menores a las reportadas por Wilcke en el en el mismo bosque.

Abstract:

Atmospheric nitrogen (N) and phosphorus (P) depositions are expected to increase in the tropics as a consequence of increasing human activities in the next decades. In the literature, it is frequently assumed that tropical montane forests are N-limited, while tropical lowland forests are P-limited. In a low-level N and P addition experiment, we determined the short-term response of N and P cycles in a north Andean montane forest on Palaeozoic shists and metasandstones at an elevation of 2100m a.s.l. to increased N and P inputs. We evaluated experimental N, P and N+ P additions (50 kg ha&#8722;1 yr&#8722;1 of N, 10 kg ha&#8722;1 yr&#8722;1 of P and 50 kg + 10 kg ha&#8722;1 yr&#8722;1 of N and P, respectively) and an untreated control in a fourfold replicated randomized block design. We collected litter leachate, mineral soil solution (0.15 and 0.30m depths), throughfall and litterfall before the treatment began (August 2007) until 16 months after the first nutrient application (April 2009). Less than 10 and 1% of the applied N and P, respectively, leached below the organic layer which contained almost all roots and no significant leaching losses of N and P occurred to below 0.15m mineral soil depth. Deposited N and P from the atmosphere in dry and wet form were retained in the canopy of the control treatment using a canopy budget model. Nitrogen and P retention by the canopy were reduced and N and P fluxes in throughfall and litterfall increased in their respective treatments. The increase in N and P fluxes in throughfall after fertilization was equivalent to 2.5% of the applied N and 2% of the applied P. The fluxes of N and P in litterfall were up to 15% and 3%, respectively, higher in the N and N+ P than in the control treatments. We conclude that the expected elevated N and P deposition in the tropics will be retained in the ecosystem, at least in the short term and hence, N and P concentrations in stream water will not increase. Our results suggest that in the studied tropical montane forest ecosystem on Palaeozoic bedrock, N and P are co-limiting the growth of organisms in the canopy and organic layer.

Abstract:

In meiner Arbeit habe ich die Auswirkungen von meteorologischen Extremereignissen auf die Konzentrationen von Calcium, Magnesium, Natrium und Kalium in der Bodenlösung eines Untersuchungsgebietes in den ecuadorianischen Anden untersucht. Dazu wurden die Konzentrationen der basischen Elemente im Streuperkolat sowie in der Bodenlösung in 15 cm und 30 cm Mineralbodentiefe gemessen und unter verschiedenen Gesichtspunkten untersucht. Die Abhängigkeit der Nährstoffkonzentration von Ca, Mg, Na und K in der Bodenlösung vom Niederschlagsvolumen konnte bestätigt werden. Die Basenkonzentrationen in der Bodenlösung nahmen mit zunehmendem Niederschlagsvolumen ab. Gleichzeitig waren die Konzentrationen im Streuperkolat am höchsten und in der Bodenlösung in 30 cm Mineralbodentiefe am geringsten. Weitergehend habe ich geprüft, ob sich die Nährstoffkonzentrationen in der Bodenlösung nach einer Trockenphase sowie nach einer Feuchtphase voneinander unterscheiden. Es zeigte sich, dass die Basenkonzentrationen in der Bodenlösung während bzw. nach einer Trockenphase anstiegen. Während Feuchtphasen stiegen die Nährstoffkonzentrationen in der Bodenlösung zunächst an, fielen bei langanhaltenden Feuchtphasen jedoch ab. Je nach basischem Element lag die Konzentration in der Bodenlösung der Trockenphasen bis zu 7mal höher als die der Feuchtphasen. Bei dem Vergleich der Basenkonzentrationswerte im Streufall mit denen der Bodenlösung war eine jahreszeitliche Korrelation festzustellen. Eine niederschlagsbedingt hohe Streufallauflage erzeugte hohe Nährstoffkonzentrationen in der Bodenlösung der oberen Bodenschichten, wobei die Konzentrationswerte jedoch mit zunehmender Bodentiefe abnahmen. In meiner Untersuchung habe ich herausgefunden, dass extreme Trockenheit sowie starke Niederschläge starken Einfluss auf die Nährstoffkonzentrationen der Bodenlösung und damit auf die Nährstoffflüsse nehmen. Eine Veränderung der Trocken- und Feuchtverhältnisse des Klimas aufgrund des Weltklimawandels führt daher auch zu einer Änderung des Elementkreislaufs und somit des Waldökosystems.

Abstract:

New South American species are described, one in each of the following genera: Ficus, Helicostylis and Naucleopsis.

Abstract:

Atmospheric nitrogen (N) and phosphorus (P) depositions are expected to increase in the tropics as a consequence of increasing human activities in the next decades. Furthermore, a possible shortened El Niño Southern Oscillation cycle might come along with more frequent calcium (Ca) depositions on the eastern slope of the Ecuadorian Andes originating from Saharan dust. It is crucial to understand the response of the old-growth montane forest in Ecuador to increased nutrient deposition to predict the further development of this megadiverse ecosystem. I studied experimental additions of N, P, N+P and Ca to the forest and an untreated control, all in a fourfold replicated randomized block design. These experiments were conducted in the framework of a collaborative research effort, the NUtrient Manipulation EXperiment (NUMEX). I collected litter leachate, mineral soil solution (0.15 and 0.30 m depths), throughfall and fine litterfall samples and determined N, P and Ca concentrations and fluxes. This approach also allowed me to assess whether N, P and/or Ca are limiting nutrients for forest growth. Furthermore, I evaluated the response of fine root biomass, leaf area index, leaf area and specific leaf area, tree diameter growth and basal area increment contributed from a cooperating group in the Ca applied and control treatments. During the observation period of 16 months after the first fertilizer application, less than 10, 1 and 5% of the applied N, P and Ca, respectively, leached below the organic layer which contained almost all roots but no significant leaching losses occurred to the deeper mineral soil. Deposited N, P and Ca from the atmosphere in dry and wet form were, on balance, retained in the canopy in the control treatment. Retention of N, P and Ca in the canopy in their respective treatments was reduced resulting in higher concentrations and fluxes of N, P and Ca in throughfall and litterfall. Up to 2.5% of the applied N and 2% of the applied P and Ca were recycled to the soil with throughfall. Fluxes of N, P and Ca in throughfall+litterfall were higher in the fertilized treatments than in the control; up to 20, 5 and 25% of the applied N, P and Ca, respectively, were recycled to the soil with throughfall+litterfall. In the Ca-applied plots, fine root biomass decreased significantly. Also the leaf area of the four most common tree species tended to decrease and the specific leaf area increased significantly in Graffenrieda emarginata Triana, the most common tree species in the study area. These changes are known plant responses to reduced nutrient stress. Reduced aluminium (Al) toxicity as an explanation of the Ca effect was unlikely, because of almost complete organocomplexation of Al and molar Ca:Al concentration ratios in solution above the toxicity threshold. The results suggest that N, P and Ca co-limit the forest ecosystem functioning in the northern Andean montane forests in line with recent assumptions in which different ecosystem compartments and even different phenological stages may show different nutrient limitations (Kaspari et al. 2008). I conclude that (1) the expected elevated N and P deposition will be retained in the ecosystem, at least in the short term and hence, quality of river water will not be endangered and (2) increased Ca input will reduce nutrient stress of the forest.

Abstract:

Cedrela montana is a deciduous broad-leaved tree species growing in the humid mountain rainforests of southern Ecuador. High-resolution dendrometer data indicate a regular seasonal growth rhythm with cambial activity during January to April. Amplitudes of daily radial stem diameter variations are correlated with the amount of the maximum daily vapour pressure deficit. During humid periods, daily stem diameter variations are considerably smaller than during drier periods. This indicates that cambial activity is limited by available moisture even in such a very humid mountain climate. Wood anatomical studies on microcores show the formation of a marginal parenchyma band at the beginning of the growth period. This parenchyma band can be used to delineate annual growth rings. We were able to establish the first ring-width chronology from Cedrela montana which covers the time until 1840. However, the chronology is presently statistically robust back to 1910 only. Correlation functions calculated with NCEP/NCAR data indicate a significantly positive relationship of tree growth with temperatures during the growth period during January to April. However, only 8% of the growth variance is explained by this climatic factor. In the future, this relationship may be useful to reconstruct past temperature conditions of the study area.

Abstract:

“There is, however, one natural feature of this country, the interest and grandeur of which may be fully appreciated in a single walk: it is the “virgin forest”. Here no one who has any feeling of the magnificent and the sublime can be disappointed.” Alfred Russel Wallace commented with these words on the wonders of the rain forest covering the Amazon Basin. If he had travelled further up, right to the origins of the Amazon, to the far-off places of Andean headwater streams, he would have encountered a forest ecosystem even more wondrous and unique – the montane cloud forest (Figure 1-1). The Merriam Webster dictionary defines cloud forests rather shortly as “wet tropical mountain forests at an altitude usually between 3000 and 8000 feet (1000 and 2500 meters) that are characterized by a profusion of epiphytes and the presence of clouds even in the dry season” (Merriam-Webster 2003). During the first international symposium on cloud forests in Puerto Rico in 1993, a more explicit collection of characteristics was put together (Hamilton et al. 1993). Here, the ecosystem is defined as having: - a distinctly floristic and structured form - an atmospheric environment with persistent cloud cover - reduced solar radiation - suppressed evapotranspiration - enhanced net throughfall input due to the stripping of clouds by the tree canopies - reduced canopy heights and gnarled tree trunks at higher altitudes - a large epiphyte biomass - wet and frequently waterlogged soils with a high organic content - extremely high biodiversity (a so-called biodiversity hotspot) - a high amount of endemism. Cloud forests are found all around the world (see Figure 1-2), far inland or on islands, and at altitutes ranging from as low as 500 m up to 3500 m (Hostettler 2002). Although only 2.5 % of the world’s tropical forests are cloud forests (Bubb et al. 2004) they are outstandingly important for sustaining life on our planet. A myriad of plants have evolved depending upon the constant fog and hundreds of animals have evolved to depend on these plants. Numerous plant species have been found to possess medicinal qualities and contribute to the health of a multitude of people each year. For example quinine, the cure for malaria, is extracted from the bark of the Cinchona tree, which was first discovered in the montane cloud forests of Peru (Régnier 2007). Other essential ecosystem services provided by cloud forests are the formation of soil, carbon sequestration, the cycling of nutrients and recreation among others (Costanza et al. 1997). The key function of cloud forest, though, is the provision of high amounts of good quality freshwater. Downstream populations depend on this provision of drinking and irrigation water, an important part of which is captured by the stripping of clouds by tree canopies. Even during drier periods, pristine cloud forests supply a reliable stream flow by draining the water which is abundantly stored in the forest vegetation and soil. Several large tropical capitals such as Quito, Tegucigalpa and Mexico city are dependent on this water and are thus intertwined with the fate of these watersheds (Hostettler 2002). Not without reason around 90 % of the world’s cloud forest sites are included in the WWF Global200 region list with conservation priority (Aldrich et al. 2000). Despite their importance, tropical forests all over the world are deforested at an overwhelming rate. The average annual deforestation rate for tropical forests in South America has been estimated to be 0.4 % for the year 2000. Amongst all South American countries, Ecuador has by far the highest deforestation rate with a lessening of the country’s forest cover of 1.2 % per year (FAO 2001). Reasons for deforestation are various, but are generally caused by population growth or shifts. The most widespread threat to tropical cloud forests is forest clearance for farming or pastures. In some countries hunting, forest fires and mining are also responsible for forest conversion or degradation. However, one of the most prevalent pressures on lowland rainforests, namely timber harvesting, is not such a big issue for cloud forests due to the mostly steep topography, and the reduced tree heights at these altitudes (Bubb et al. 2004). Even though the intrinsic and economic values of cloud forests are widely acknowledged, our understanding of the drivers of ecosystem functioning is still deficient. Sadly, the scarce knowledge about these fragile systems poses a hindrance for effective conservation management and future policy decisions (McClain & Naiman 2008).

Abstract:

Der fortschreitenden Vernichtung megadiverser tropischer Bergregenwälder kann nur durch Wiederaufforstung mit indigenen Arten nachhaltig entgegengewirkt werden. Das dafür benötigte Pflanzmaterial wird zum Großteil durch vegetative Vermehrung gewonnen. Dieses Buch liefert bisher noch ausstehendes Grundlagenwissen, indem es die Zusammenhänge zwischen dem Bewurzelungspotenzial und der Physiologie von mehreren, in den ecuadorianischen Anden beheimateten Baumarten beleuchtet. Insbesondere wurden dafür lösliche Zucker, Stärke, die Phytohormone Auxin und Cytokinin sowie die stomatäre Leitfähigkeit analysiert. Außerdem werden die Ergebnisse umfassender Vermehrungsexperimente mit Stammstecklingen und Mooslingen detailliert dargestellt. Für den Praktiker werden die Erkenntnisse in ausführlichen und unter einfachen Bedingungen umsetzbaren Klonierungsprotokollen für die beiden Arten Heliocarpus americanus und Tabebuia chrysantha aufbereitet. Im Besonderen wird das Stressen der Mutterpflanzen als bislang kaum genutztes Werkzeug zur Einflussnahme auf den Inhaltsstoffwechsel bei der Stecklingsvermehrung vorgestellt.

Abstract:

Impacts of different terrain configurations on the general behaviour of idealised katabatic flows are investigated in a numerical model study.Various simplified terrain models are applied to unveil modifications of the dynamics of nocturnal cold drainage of air as a result of predefined topographical structures. The generated idealised terrain models encompass all major topographical elements of an area in the tropical eastern Andes of southern Ecuador and northern Peru, and the adjacent Amazon. The idealised simulations corroborate that (i) katabatic flows develop over topographical elements (slopes and valleys), that (ii) confluence of katabatic flows in a lowland basin with a concave terrainline occur, and (iii) a complex drainage flow system regime directed into such a basin can sustain the confluence despite varying slope angles and slope distances.

Abstract:

The multidisciplinary research unit &#147;Biodiversity and Sustainable Management of a Megadiverse Mountain Ecosystem in South Ecuador&#148; established a central data management system to provide the members with all gathered scientific data. Additionally to the database functionality of the system the web based layout is capable to present general information on the research unit to the public and support accounting and administration of the project. All parts of the system are implemented using open-source or free software. A major task is the allocation of a sophisticated and detailed metadata scheme. The standardised ecological metadata language (EML) is used as the basis for metadata information stored in a relational database. The describing datatypes are highly modular and can be expanded if necessary. Data input and searching is implemented through a dynamic webinterface with easy to use forms. This is important to increase the acceptance by the users of the system. Searching the database is possible by strings for keywords, authors, etc. or by geographic locations. Except for gridded data, all single values of the datasets are stored in relational tables and thus, it is possible to extract only parts of a whole dataset during data download. While the system is already operational, modifications and new features are continuously implemented.

Abstract:

Mycorrhizas of vascular plants and mycorrhiza-like associations of liverworts are integral parts of terrestrial ecosystems, but have rarely been studied in tropical mountain rain forests. Our lightand electron microscopical studies at the RBSF revealed that the roots of nearly all tree species were well colonized by structurally diverse arbuscular mycorrhizal Glomeromycota (Haug et al. 2004, Beck et al. 2005), a few tree species by ectomycorrhizal Ascoand Basidiomycota (Haug et al. 2005), and that epiphytic, pleurothallid orchids formed mycorrhizas with Tulasnella species and members of the Sebacinales (Basidiomycota) (Suárez et al. 2006, Kottke et al. 2007). Species of Sebacinales also occurred in mycorrhizas of hemiepiphytic ericads (Setaro et al. 2006) and Tulasnella species were found in liverworts belonging to the Aneuraceae (Kottke et al. 2007). Traditionally, studies on biodiversity and host specificity have been based on morphologically defined species. No such approach was feasible in the case of the mycobionts in our study as the fungi did not display sufficient structural differences in the mycorrhizas for delimitation of morphospecies. The identification of the mycorrhiza-forming fungi in the forest could be done neither by spore nor by fruiting-body sampling, as both methods would have yielded only a very narrow spectrum of the fungal communities (Husband et al. 2002, Sanders 2004a). Instead, direct sequencing of the associated fungi from the plant material was carried out (Kottke et al. 2007). Given our present stage of knowledge, the sequence types (ribosomal genotypes) can rarely be precisely related to either morphological or biological species. However, the amount of information derived from the sequences of the ribosomal genes appeared to be meaningful in previous ecological studies on arbuscular mycorrhizas (Helgason et al. 2002, Husband et al. 2002, Sanders 2004b) as well as on mycorrhiza-forming Basidiomycota (Bidartondo et al. 2003, Bidartondo et al. 2004). However, analysis of biodiversity and specificity of the mycobionts from field samples using DNA sequences also poses problems. Firstly, results are limited by the available primers. Secondly, problems resulted from the observation that the ribosomal genes can show intraspecific variation, especially in the case of the multinucleate Glomeromycota (Sanders et al. 1995, Lloyd-Macgilp et al. 1996, Clapp et al. 2001, Sanders 2004b). These facts pose general, unresolved challenges to a species concept based on meaningful levels of genetic diversity. Thus the list of fungal sequences presented here is far from being complete and far from being a species list.

Abstract:

Soil landscape modelling is based on understanding the spatial distribution patterns of soil characteristics. A model relating the soil?s properties to its position within the landscape is used to predict soil properties in other similar landscape positions. To develop soil landscape models, the interaction of geographic information technology, advanced statistics and soil science is needed. The focus of this work is to predict the distribution of the different soil types in a tropical mountain forest area in southern Ecuador from relief and hydrological parameters using a classification tree model (CART) for soil regionalisation. Soils were sampled along transects from ridges towards side valley creeks using a sampling design with 24 relief units. Major soil types of the research area are Histosols associated with Stagnosols, Cambisols and Regosols. Umbrisols and Leptosols are present to a lesser degree. Stagnosols gain importance with increasing altitude and with decreasing slope angle. Umbrisols are to be found only on slopes <30°. Cambisols occurrence might be related to landslides.The CART model was established by a data set of 315 auger sampling points. Bedrock and relief curvature had no influence on model development. Applying the CART model to the research area Histosols and Stagnosols were identified as dominant soil types. Model prediction left out Cambisols and overestimated Umbrisols, but showed a realistic prediction for Histosols, Stagnosols and Leptosols.

Abstract:

From July to October 2009 different methods for the measurement of suspended sediment yield and related particulate carbon (C) and nitrogen (N) loss were investigated in a mountainous cloud forest catchment in South-Ecuador. Humid mountainous regions in the tropics are often characterized by highly variable discharge, high rainfall erosivity and geomorphic instability which result in a greatly increased erosion risk. Additionally this danger is enhanced in the studied catchment by the conversion of cloud forests to pasture and crop land as well as landslides caused by road construction. To be able to quantify suspended sediment yield and the associated particulate organic carbon (POC) and nitrogen (NOC) export, a direct approach of suspended sediment sampling, gravimetric ascertainment of the quantity and C and N analysis was combined with the application of two different turbidity sensors. The first one, a ViSolid sensor (WTW, Weilheim, Germany), was set up at the catchment outlet. The second one, a TSS Portable sensor (Hach Lange, Düsseldorf, Germany), was used as a mobile hand held unit. Relations from correlation and regression analysis between suspended sediment concentration and discharge and turbidity respectively made it possible to calculate first extrapolations of yearly suspended sediment yield between 26,5 t ha-1 and 46,3 t ha-1. These numbers are clearly below the global average of 200 t suspended sediment ha-1 a-1. For POC export, the results were between 272,8 kg ha-1 a-1 and 446,9 kg ha-1 a-1 and for NOC export between 21,2 kg ha-1 a-1 and 34,7 kg ha-1 a-1. The PON value fits to literature data whereas POC value is above literature data. The differing results and the unexpected low suspended sediment yield can be explained by the fact that more data integrating the temporal variation of suspended sediment discharge during the year are needed for an adequate calculation. Furthermore emphasis to a greater extent should be placed on the improvement of the data calibration for the ViSolid sensor.

Abstract:

Ziel dieser Arbeit war es, ein Licht auf die Zusammenhänge zwischen Landnutzung, den Habitateigenschaften im Gewässer und den lokalen Makroinvertebratengemeinschaften zu werfen. Dazu wurden Proben des Makrozoobenthos genommen und zahlreiche Umweltvariablen erfasst. Anschließend wurde mit univariater und multivariater Statistik herausgearbeitet, welche Faktoren die Verbreitung von Wirbellosen wesentlich steuern. Die zwei vorherrschenden Landnutzungstypen der Weidebewirtschaftung und Waldnutzung mit geringer Eingriffsintensität unterscheiden sich signifikant in ihrem Einfluss auf die Fließgewässer im Grad der Beschattung, Vbase, pH-Wert, EC und Alkalinität. Die CCA zeigt, dass die Faunastruktur, neben diesen Parametern, stark mit dem Substrattyp korreliert ist. Dies spiegelt sich auch in der aquatischen Wirbellosenfauna wider. Insgesamt sind 44% der gefundenen Taxa in ihrer Verbreitung auf eine Landnutzungsform beschränkt. Typische Taxa in Einzugsgebieten mit extensiver Viehwirtschaft und geringer Bewaldung sind Blephariceridae gen.1, Empididae, Macrostemum, Petrophila, Phanocerus, Psychodidae gen. 1, Tabanidae, Andesiops, Haplohyphes, Baetodes, Leptohyphes, Smicridea und Thraulodes. Diese Makroinvertebraten bevorzugen vor allem hohe Werte für EC, pH, Alkalinität und Vbase. In Fließgewässern mit angrenzendem Wald ist die absolute Taxazahl und Eveness höher. Die Individuendichte ist geringer. Die Diversitätsindizes von Shannon-Wiener, Margalof oder Simpson ergeben in der Summe keine deutlichen Unterschiede zwischen den Landnutzungstypen. In Fließgewässern mit angrenzendem Wald sind Hetaerina, Polythore, Argia, Atanatolica, Farrodes, Phylloicus, Bezzia, Molophilus, Cernotina und Sialis typische Vertreter des Makrozoobenthos. Die entscheidenden Parameter sind für diese Taxa ein hoher Grad an Beschattung, viel Feinsubstrat und eine geringe Vbase. Vor allem die Ordnung der Odonata wäre bei weiterer Abholzung der Wälder im Untersuchungsgebiet bedroht.

Abstract:

The montane forests of Ecuador are part of one of the world?s hotspots of biodiversity and they also suffer the highest deforestation rate amongst South American countries. The processes that drive the dynamics of these highly diverse ecosystems are poorly understood. This is particularly true for transient dynamics, which are crucial for the protection and sustainable management of such forests. Dynamic simulation models can be used to analyse the growth of forests, but so far they have been applied mostly to temperate forests and to some few tropical lowland forests. In this study we investigate whether a process-based, individual-oriented simulation model like FORMIND is capable of reproducing the dynamics of tropical montane forests. For this purpose we develop a parameterisation for the model and validate the model against field observations of different (structural) patterns. We then analyse the predicted succession dynamics. The model is capable of reproducing the structure and dynamics of mature ridge forest on different levels of complexity. The main results indicate that, in terms of relative abundances of different species groups and stem size distribution in the tree community, our model predicts the observed patterns in the field. Additional field studies and model modifications are required to simulate the succession processes that follow different types of disturbances. FORMIND is a promising tool for the extrapolation of local measurements and for simulating the dynamics of tropical montane forests. Parameterisations of the model for further forest types within the research area are intended. The model has a number of potential applications, ranging from investigating the impact of (different) natural disturbances on forest structure and tree species diversity to analysing different potential management strategies.

Abstract:

The thermal structure of a megadiverse mountain ecosystem in southern Ecuador is examined on the basis of temperature measurements inside the natural mountain forest and at open-sites along an altitudinal gradient from 1600 to 3200 m. The main methodological aim of the current study is to develop an air temperature regionalization tool to provide spatial datasets on average monthly mean, minimum and maximum temperature by using observation data. The maps, based on data of the period 1999?2007, are needed by ecological projects working on various plots where no climate station data are available. The temperature 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 thermal structure of both manifestations of our ecosystem (pastures and natural vegetation) with special considerations to the ecosystem temperature regulation service by converting natural forest into pasture. The results reveal a clear thermal differentiation over the year, partly triggered by the change of synoptic weather situation but also by land cover effects. Thermal amplitudes are particularly low during the main rainy season when cloudiness and air humidity are high, but markedly pronounced in the relative dry season when daily irradiance and outgoing nocturnal radiation cause distinct differences between the land cover units. Particularly the lower pasture areas gained by slash and burn of the natural forest exhibit the most extreme thermal conditions while the atmosphere inside the mountain forest is slightly cooler due to the regulating effects of the dense vegetation. Thus, clearing the forest clearly reduces the thermal regulation function (regulating ecosystem services) of the ecosystem which might become problematic under future global warming.

Abstract:

Abstract: For the first time in tropical mountain rain forest, arbuscular mycorrhizal fungal richness and community composition was investigated from planted seedlings of Cedrela montana, Heliocarpus americanus, Juglans neotropica and Tabebuia chrysantha in reforestation plots on degraded pastures. A segment of fungal 18S rDNA was sequenced from the mycorrhizas. Sequences were compared with those obtained from mycorrhizas of adult trees of 30 species in the neighboring, pristine tropical mountain rain forest. In total, 193 glomeromycotan sequences were analyzed, 130 of them previously unpublished. Members of Glomeraceae, Acaulosporaceae, Gigasporaceae and Archaeosporales were found in both habitats, with Glomus Group A sequences being by far the most diverse and abundant. Glomus Group A sequence type richness did not appear to differ between the habitats; a large number was observed in both. Glomus Group A sequence type composition, however, was found distinctly different. Seedlings were rarely colonized by fungi of the pristine forest but trapped a number of fungi known from other areas, which were rarely found in the pristine forest.

Abstract:

Distinctive groups of fungi are involved in the diverse mycorrhizal associations of land plants. All previously known mycorrhiza forming Basidiomycota associated with trees, ericads, liverworts or orchids are hosted in Agaricomycetes, Agaricomycotina. Here we demonstrate for the first time that Atractiellomycetes, members of the ?rust? lineage (Pucciniomycotina), are mycobionts of orchids. The mycobionts of 103 terrestrial and epiphytic orchid individuals, sampled in the tropical mountain rain forest of Southern Ecuador, were identified by sequencing the whole ITS1-5.8S-ITS2 region and part of 28S rDNA. Mycorrhizae of 13 orchid individuals were investigated by transmission electron microscopy. Simple septal pores and symplechosomes in the hyphal coils of mycorrhizae from four orchid individuals indicated members of Atractiellomycetes. Molecular phylogeny of sequences from mycobionts of 32 orchid individuals out of 103 samples confirmed Atractiellomycetes and the placement in Pucciniomycotina, previously known to comprise only parasitic and saprophytic fungi. Thus, our finding reveals these fungi, frequently associated to neotropical orchids, as the most basal living basidiomycetes involved in mycorrhizal associations of land plants.

Abstract:

To study vegetation/modern pollen rain relationship a total of 41 pollen traps have been installed for one year on an altitudinal transect between 1800 and 3185 ma.s.l. elevation in the montane forest and páramo vegetation type of the ECSF research area, located between Loja and Zamora in the southeastern Ecuadorian Andes. Results revealed that the altitudinal vegetation gradient of lower montane forest, upper montane forest, subpáramo and páramo is well reflected in the modern pollen rain data. Principal component analysis (PCA) on the pollen rain data indicate that a high number of pollen and spore taxa are characteristic for one vegetation type or reflect the altitudinal distribution of genera and families of modern vegetation. However, a considerable number of pollen and spore taxa not representing modern vegetation types were identified as well. Wind dispersal is supposed to be responsible for differences found between plant and pollen distribution patterns. Characteristic pollen and spore taxa for the lower montane forest are Alchornea, Heliocarpus and Hyeronima; for the upper montane forest Cyathea spp., Elaphoglossum ciliatum and Purdiaea nutans; and for the subpáramo Cyperaceae, Ericaceae, Jamesonia and Valeriana. The position of the modern upper timberline in the research area is reflected in the pollen rain by an increase of subpáramo taxa and a decrease of montane forest taxa.

Abstract:

A lake sediment record from Laguna Campana at 2,488 m a.s.l. in the eastern Ecuadorian Andes allows the reconstruction of local environmental conditions over the past 500 years. A high-resolution multi-proxy approach using pollen, spore, charcoal and XRF analyses provides information about lake genesis, hydrological variations and the development of the surrounding vegetation. Results suggest that Laguna Campana originated from a landslide, which are naturally common and anthropogenically promoted in the study area. Human activities, e.g. deforestation or slash and burn cultivation, impacted the local vegetation development and biodiversity during the recorded period. After a first dense layer of pioneer grasses developed on open soil around the small lake, successional stages of secondary upper mountain rainforest forest mainly composed of Alnus and Weinmannia were observed. The record shows no signs of dense forest regeneration but rather open vegetation with trees and a grassy understory. Especially since ca. A.D. 1980, the proportion of forest in the area was reduced, most probably by fire use for pastures, cultivation and wood extraction. Hydrological variability was derived from differences in minerogenic input and variations in Botryococcus braunii and Sphagnum occurrence. After wettest conditions at the study site, probably triggering the landslide, humid conditions persisted until a time of drier conditions between A.D. 1900 and 1960. A subsequent return to wetter conditions was observed over the last decades. XRF analyses suggest an increase in deposition of atmospherically derived lead since the formation of the lake.

Abstract:

It is commonly presumed that plant respiratory CO2 release increases with increasing temperature. However, we report on very contrasting stem CO2 release (R S)?temperature relationships of trees in a species-rich tropical montane forest of southern Ecuador under dry and wet season conditions. Rates of R S were low and completely uncoupled from the dial temperature regime during the humid season. In contrast, during the dry season, R S was generally higher and temperature sensitivity of R S differed greatly in degree and even in the direction of response, indicating that temperature might not be the only determinant of R S. In order to explain the heterogeneity of R S, we related R S to vapour pressure deficit, wind speed and solar radiation as important abiotic drivers influencing transpiration and photosynthesis. Stepwise multiple regression analyses with these meteorological predictors either were biased by high collinearity of the independent variables or could not enhance the ability to explain the variability of R S. We assume maintenance respiration to dominate under humid conditions unfavourable for energy acquisition of the tree, thus explaining the pronounced uncoupling of R S from atmospheric parameters. In contrast, the drier and hotter climate of the dry season seems to favour R S via enhanced assimilatory substrate delivery and stem respiratory activity as well as elevated xylem sap CO2 imports with increased transpiration. In addition, tree individual differences in the temperature responses of R S may mirror diverging climatic adaptations of co-existing moist forest tree species which have their distribution centre either at higher or lower elevations.

Abstract:

Abstract We investigated controls on the water chemistry of a South Ecuadorian cloud forest catchment which is partly pristine, and partly converted to extensive pasture. From April 2007 to May 2008 water samples were taken weekly to biweekly at nine different subcatchments, and were screened for differences in electric conductivity, pH, anion, as well as element composition. A principal component analysis was conducted to reduce dimensionality of the data set and define major factors explaining variation in the data. Three main factors were isolated by a subset of 10 elements (Ca2?, Ce, Gd, K?, Mg2?, Na?, Nd, Rb, Sr, Y), explaining around 90% of the data variation. Land-use was the major factor controlling and changing water chemistry of the subcatchments. A second factor was associated with the concentration of rare earth elements in water, presumably highlighting other anthropogenic influences such as gravel excavation or road construction. Around 12% of the variation was explained by the third component, which was defined by the occurrence of Rb and K and represents the influence of vegetation dynamics on element accumulation and wash-out. Comparison of base- and fast flow concentrations led to the assumption that a significant portion of soil water from around 30 cm depth contributes to storm flow, as revealed by increased rare earth element concentrations in fast flow samples. Our findings demonstrate the utility of multi-tracer principal component analysis to study tropical headwater streams, and emphasize the need for effective land management in cloud forest catchments.

Abstract:

not available