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

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−1 net rainfall rates. Sites with FS≥1 at 3 mm h−1 (complete saturation) were classified as unconditionally stable; sites with FSb1 at 0.001 mm h−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.

Abstract:

This paper analyses the effectiveness and distributional effects of payments to avoid tropical deforestation. As a first aspect, we investigated whether or not expected payments for avoided deforestation would be acceptable for tropical farmers in Southern Ecuador, with the study area located directly adjacent to the Podocarpus National Park. Second, we explored possible distributional effects resulting from voluntary or mandatory remuneration schemes to avoid deforestation. Finally, a productive sustainable land use was conceptualised to be combined with payments for avoided deforestation to avoid leakage (i.e. deforestation processes elsewhere when avoided at a given farm). Farm level land use scenarios with ("business as usual") and without deforestation ("conservation strategy") were compared. Compensation per Mg Carbon (C) that is not emitted into the atmosphere under the "conservation strategy" was derived to achieve a monetary land net present value (NPV, sum of discounted future net revenues) equal to the NPV obtained under "business as usual". Avoided carbon emissions were computed from above ground C in tropical forests of the project area and supplemented by information on soil carbon from another study. Economic data for cattle pasturing were obtained from a farm survey (130 households) to investigate distributional effects. To derive sustainable land use concepts, a risk sensitive bioeconomic farm model was used that considered effects of risk compensation when combining pasture with reforestation of abandoned farm lands and selective logging of natural forests. The results showed that only a few farmers (20 out of 130) would possibly accept a compensation price of US$ 10 per Mg avoided C emission, a C-compensation that is believed by other authors to reduce deforestation by 65%. Rather a compensation of around US$ 25 per Mg C was necessary to address compensation requirements of farmers who hold 50% of the tropical forest area in our study. The implementation of a voluntary remuneration scheme for avoided deforestation would not introduce systematic distributional effects (such as that only the biggest farmers would benefit from compensation), while a mandatory and enforced ban on deforestation coupled with a "fair" compensation payment equal to mean compensation requirements may lead to undesirable effects for many farmers. Finally, we demonstrate a mixed sustainable land use concept that depended on cheap credits for reforestation of abandoned pasture lands. This concept was able to stop farm level deforestation and to enlarge the economic value of farms through various combined land use options (agricultural and forestry options). The combination of land uses led to risk compensatory effects and a more efficient land use by reintegrating unproductive abandoned areas back into the economical process. In our conclusion a combination of payments for avoided deforestation along with productive land use concepts provided a viable solution for tropical forest conservation.

Abstract:

Analyses were carried out on financial compensation to avoid loss of tropical forests and related carbon (C) emissions when marginal financial yield declined for land-use options with extended areas, and when a riskaverting perspective (modeled according to financial theory around the capital asset pricing model) is assumed. The approach in this study was to consider natural forest, forest plantation, pasture, and cropland simultaneously to investigate how an optimized land-use distribution may reduce the amount of compensation necessary to avoid C emissions from forest loss. The financial compensations derived were as high as US$ 176 per hectare per year when comparing natural forests only with the most profitable alternative (croplands). However, compensation decreased to US$ 124 for risk-neutral decision-makers, who would strive for optimized land-use allocation, and to only US$ 47 per hectare per year for risk-avoiders, who would look to maximize the reward-to-variability ratio. Sensitivity analyses indicated that the compensation under risk-aversion increased much less than under risk-ignoring when increased productivity of agricultural land-use or growing demand for agricultural products was simulated. It was concluded that considering appropriate diversification strategies and the well documented human behavior to avoid risks is an important step in developing cost-effective compensation policies.

Abstract:

Este evento académico, que se inició el año pasado, busca establecer puentes de investigación y de comunicación entre distintas disciplinas y salud. En 2008 como señal de nuestra disposición al diálogo, escuchamos las miradas y los aportes de la ética, filosofía, sociología, ciencias políticas, psicología, historia, antropología, comunicación, economía y educación. Este año con la generosa y entusiasta participación de la Facultad de Arquitectura, Diseño y Artes y la Escuela de Ciencias Geográficas, organizamos el Diálogo Académico 2009 con el título Miradas desde el territorio, la arquitectura, la geografía hacia la salud pública para mirar institucional y académicamente desde el territorio, el espacio y la geografía hacia la investigación, la gestión y las políticas de la salud pública. Seleccionamos territorio porque en el nuevo escenario político de cambios institucionales dispuestos en la Constitución vigente y en el Plan Nacional de Desarrollo, se propone la Estrategia Territorial Nacional … “concebida como el conjunto de criterios específicos y lineamientos que articulan las políticas públicas a las condiciones y características propias del territorio y constituyen referentes sustantivos para las políticas sectoriales y territoriales”, una estrategia que evidentemente repercutirá en las condiciones de vida y la salud de la población. La aplicación de esta Estrategia Territorial Nacional requiere el mayor debate nacional para dotarla de la necesaria y suficiente legitimidad social que proporcione la máxima sustentabilidad política posible a los cambios institucionales que propone. Porque el territorio como nos recuerda la sociología es con la ley, la nación, la lengua, el ejército, un elemento fundamental de la vida social y un requisito en la construcción del Estado moderno. Más todavía si tenemos presente que la creación europea del Estado nacional unitario fue una construcción social violenta, que reconoció la apropiación del territorio por y para una sola nación con identidad plena, que había logrado excluir todo lo diferente a ella. Nosotros, Ecuador, que somos una realidad bastante distinta de la europea generadora de ese Estado nacional unitario, nosotros que somos diversos, pluriculturales, plurinacionales… requerimos saber las concepciones, las políticas, los imaginarios que sustentan la Estrategia Territorial Nacional, primordialmente las nociones de Estado y de construcci??n de un Estado que reconozcan y acepten la diversidad de entidades sociales de los pueblos, nacionalidades y culturas ecuatorianas. Por ello invitamos a la Senplades, para que nos presente los lineamientos generales de la Estrategia Nacional Territorial en el contexto del Plan Nacional de Desarrollo, del Plan para el Buen Vivir. Para conocer las respuestas de las instituciones de la salud a la Estrategia Nacional Territorial invitamos al Ministerio de Salud Pública, al Seguro General de Salud Individual y Familiar del IESS, al Seguro Social Campesino, a la Secretaría de Salud del Distrito Metropolitano de Quito. Los planteamientos institucionales de salud a la reforma territorial, en el contexto del acceso universal, la gratuidad, complementarán el marco institucional de reforma territorial relacionado con salud. El Instituto de Medicina Tropical Príncipe Leopoldo de Amberes Bélgica compartirá la experiencia internacional en la construcción de los distritos de salud, y la Organización Panamericana de la Salud expondrá el hospital como un espacio que promueve salud y enfatizará sobre las relaciones de interculturalidad, territorio y salud. Luego de las miradas institucionales, la Facultad de Arquitectura, Diseño y Artes de la PUCE nos presentará las miradas de sus carreras y disciplinas porque como dice su misión: “No existe actividad del ser humano que no se realice en un espacio definido por una forma, sea esta arquitectónica o urbana, no existe actividad del ser humano que no necesite el soporte de una imagen o de un objeto, sea este de dos o tres dimensiones, y estos elementos tienden no solo a facilitar la realización de estas actividades desde una consideración utilitaria, sino que comportan una alta carga simbólica, de comunicación y estética, que contribuyen a la construcción de espíritus positivos y proactivos, que además, cuando estos elementos no son resueltos con adecuadas condiciones de pertinencia y calidad de vida, no generan expectativas, ahondan los complejos atávicos y nos llevan a la pobreza”. Cerrando este Diálogo Académico 2009, la Escuela de Ciencias Geográficas de la PUCE, que celebra 20 años de su creación, expondrá cómo este campo de conocimiento y de intervención disciplinar mira a la salud pública porque tal como dice el mensaje del director de esta escuela: “Actualmente se define a la Geografía como el estudio de las relaciones entre la sociedad humana y la naturaleza. Esta visión tiene tres posibilidades: la influencia de la naturaleza sobre el desarrollo de la humanidad; la acción del ser humano en la transformación de la naturaleza; y, la interacción entre factores naturales y humanos. Así la Geografía estudia el establecimiento, mantenimiento y la ruptura del equilibrio entre el ser humano y la naturaleza”. Así este Diálogo Académico 2009 pretende contribuir al debate, que con seguridad se abrirá en torno a la reforma territorial y a la nueva organización y distribución de servicios de salud, pretende aportar argumentos no solamente al debate de los cambios institucionales propuestos, sino también al debate de la participación social tan necesaria para la aceptación de toda reforma. Agradezco a las autoridades de la PUCE, al señor rector y a la Dirección General Académica por su permanente apoyo al Instituto de Salud Pública ISP, al decano de la Facultad de Medicina, al decano de Arquitectura, Diseño y Artes por su generosa participación, al director y a la comunidad académica que hacen la Escuela de Ciencias Geográficas, un agradecimiento especial por permitir sumarnos a la celebración de sus primeros veinte años de creación, aprovecho esta oportunidad para expresarles la felicitación del ISP. Agradezco a los auspiciantes de este Diálogo Académico: la PUCE, el IMT de Amberes, a la Cooperación para el Desarrollo del Gobierno de Bélgica, a la OPS, a los participantes de la Senplades, del MSP, del SGSIF/IESS, del SSC, SS/DMQ, del IMT, de la OPS, de la FADA y de la Escuela de Ciencias Geográficas, a los profesores extranjeros, a la infatigable coordinadora del evento Dra. Miriam Buitrón Vega y a los compañeros del ISP.

Abstract:

Pteridium spp. (bracken) is one of the most persistent weeds worldwide. This communication reports for the first time, experiments to control the aggressive neotropical fern, Pteridium arachnoideum. In South Ecuador, where former pastures are overgrown by P. arachnoideum, 13 different control easures were repeated six times over a time period of 23 months: cutting of the fronds, various herbicides, covering with plastic sheeting and alternating combinations thereof. Subsequently, the pasture grass Setaria sphacelata was planted. Growth of P. arachnoideum and later the grass was monitored monthly using the variables cover and height of vegetation. Pteridium arachnoideum frond biomass was determined at the end of the treatments. None of the treatments resulted in a complete eradication of the weed. The efficacy of the reatments differed considerably, but the subsequently planted grass balanced out these differences, suppressing the fern to a cover of <40%. Thus, in spite of the high resistance of P. arachnoideum to any kind of control, regeneration of abandoned pastures is possible, using a two-step strategy: (i) depleting the reserves in the rhizomes by repeated killing of the leaves and (ii) subsequent suppression by a highly competitive pasture grass. For practical weed management, three consecutive treatments with the herbicide mixture of picloram and metsulfuron methyl, or four consecutive cuts of the fronds, are recommended at intervals of four months to achieve maximum control.

Abstract:

Forest fragmentation can negatively affect tropical epiphyte diversity, but the processes leading to such impoverishment are insufficiently understood. Due to a lack of experimental studies, the relative influence of dispersal constraints vs. growth conditions remains particularly controversial. This paper addresses the fate of late juvenile and adult vascular epiphytes in response to severe forest disturbance in montane southern Ecuador. Plant growth and survival on trunks and lower branches of isolated remnant trees was studied for the first three years following clear-cutting. Overall epiphyte mortality was substantially increased on remnant trees (72% over 3 years) relative to undisturbed forest (11%). Mortality on remnant trees was higher during the first year (52%) than during the second (20%) and third year (26%). Pteridophytes and dicots suffered higher losses than monocots. Plants surviving on remnant trees generally showed a marked negative growth regarding maximum leaf length, whereas the annual increment in leaf number varied more strongly among taxa (families). The present study provides the first field-experimental evidence for the adverse effects of forest disturbance on the performance of later, well-established life stages of vascular epiphytes. The results suggest that growth conditions may often be a more important predictor of epiphyte diversity in disturbed habitats than dispersal constraints. Similar plant responses can be expected to occur along forest edges. Therefore, the retention of scattered green trees, narrow strips or small fragments of forest are unlikely to be sufficient management tools for the conservation of epiphyte diversity in tropical landscapes.

Abstract:

Although vascular epiphytes contribute substantially to the biodiversity of tropical montane forests, it is unclear how their diversity and community composition is affected by forest alteration. We studied the response of vascular epiphyte assemblages to different intensities of land-use in a montane wet forest of northeastern Ecuador: (1) unmanaged mature forest; (2) mature forest with mid- and understorey opened for cattle grazing; and (3) isolated remnant trees in cattle pastures. The numbers of individuals and species of epiphytes per host tree did not differ significantly between land-use types, neither did total epiphyte species richness (n = 30 trees). However, total species richness of pteridophytes was signi&#64257;cantly lower on isolated remnant trees compared to unmanaged forest, whereas several taxa rich in xerotolerant species (Bromeliaceae, Orchidaceae, Piperaceae) exhibited the opposite trend. An analysis of floristic composition using ordination (NMS) and randomisation techniques (MRPP) showed that epiphyte assemblages on isolated remnant trees were significantly distinct from unmanaged forest while managed forest was intermediate between those two vegetation types. Ordination analysis further indicated reduced floristic heterogeneity in disturbed habitats. These results suggest considerable, rapid species turnover since land-use change 6 years prior to study, with pteridophytes being replaced by more xerotolerant taxa. We attribute this floristic turnover primarily to changes in microclimate towards higher levels of light and desiccation stress associated with forest disturbance. Our results support the notion that community composition offers a more sensitive indicator of human disturbance than species richness.

Abstract:

The timing of the origin of present day Neotropical animal diversity is still a matter of debate. For a long time, a preponderance of glacial (i.e. Pleistocene) radiations has been proposed. However, recent data from molecular clock studies indicate a preglacial origin for most of the examined taxa. We performed a fossil-calibrated molecular dating analysis of the genus Eois, which is a major component of one of the world?s most diverse assemblages of herbivorous insects. We found that diversification of Eois took place in the Miocene following a pattern best explained by density-dependent diversification. A strong slowdown of diversification towards the present was detected. Diversification of Eois does overlap with increased Andean uplift and diversification of the most commonly used host plant genus Piper. These findings match the patterns found for the majority of Neotropical tetrapods and for three other unrelated, ecologically different lepidopteran genera.

Abstract:

Ideas on the spatial variation of biodiversity often imply a causal link between the abundance and species richness of organisms. We investigated this ?more individuals hypothesis? using light-trapping data of three unrelated groups of moths (Arctiidae, Geometridae and Pyraloidea) from the Ecuadorian Andes. We analyzed environmental correlates of specimen densities found in different habitats, finding effects of temperature, moonlight, forest succession, elevation and season. We corrected abundance data for light-trapping artefacts, and we measured species diversity with various metrics known to be unbiased by undersampling. We found significant positive correlations between abundance and species diversity for all three taxonomic groups. We discuss implications for a general evaluation of species-energy theory as well as for a better understanding of ecological processes in montane habitats of the Andes.

Abstract:

To improve our knowledge of the influence of land-use on solute behaviour and export rates in neotropical montane catchments we investigated total organic carbon (TOC), Ca, Mg, Na, K, NO3 and SO4 concentrations during April 2007?May 2008 at different flow conditions and over time in six forested and pasture-dominated headwaters (0.7?76 km2) in Ecuador. NO3 and SO4 concentrations decreased during the study period, with a continual decrease in NO3 and an abrupt decrease in February 2008 for SO4. We attribute this to changing weather regimes connected to a weakening La Nina event. Stream Na concentration decreased in all catchments, and Mg and Ca concentration decreased in all but the forested catchments during storm flow. Under all land-uses TOC increased at high flows. The differences in solute behaviour during storm flow might be attributed to largely shallow subsurface and surface flow paths in pasture streams on the one hand, and a predominant origin of storm flow from the organic layer in the forested streams on the other hand. Nutrient export rates in the forested streams were comparable to the values found in literature for tropical streams. They amounted to 6?8 kg ha&#8722;1 y&#8722;1 for Ca, 7?8 kg ha&#8722;1 y&#8722;1 for K, 4?5 kg ha&#8722;1 y&#8722;1 for Mg, 11?14 kg ha&#8722;1 y&#8722;1 for Na, 19?22 kg ha&#8722;1 y&#8722;1 for NO3 (i.e. 4.3?5.0 kg ha&#8722;1 y&#8722;1 NO3-N) and 17 kg ha&#8722;1 y&#8722;1 for SO4. Our data contradict the assumption that nutrient export increases with the loss of forest cover. For NO3 we observed a positive correlation of export value and percentage forest cover.

Abstract:

The evaporative loss of intercepted water from the canopy constitutes an important element of the water budget of forests. Starting April 1998, incident precipitation (P), throughfall (TF), and stemflow (SF) were measured in five transects laid out in three small watersheds (~10 ha each) with lower montane rain forest at 1900?2200 m.a.s.l. in South Ecuador. Interception loss (I) was also modeled using the analytical model of Gash (1979). The storage capacity of the leaves and of the trunks and branches, as well as the direct throughfall, and stemflow fractions were determined using conventional regression approaches. In addition, apparent total evaporation (ET) was determined from the water budget for the three watersheds. Mean annual P in the first 4 years ranged between 2363 and 2592 mm among the three watersheds. Average I derived from weekly measurements of P, TF, and SF ranged between 2.0 and 3.5 mm/day (i.e. 32?50% of P). Modeled average I was similar to measured values at 2.1?3.4 mm/day (32?49% of P). We found that I constituted an important part of the average estimated watershed ET of 3.5?4.3 mm/day. The high evaporative losses are attributed to a combination of low rainfall intensities, the usual absence of fog, high canopy density, abundant epiphytes, and advected energy from lower elevations.