Publications
Found 861 publication(s)
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Calvas, B. (2018): Compendio informativo de especies de árboles nativos en la Provincia de Loja, Ecuador, Issue 2. Instituto di Silvicultura TUM, Freising, Germany.
Aramayo, V.; Wörle, A. & Hildebrandt, P. (2018): Manual curso de arborismo para la recolección de semillas, Issue 1. Instituto di Silvicultura TUM, Freising, Germany.
Delsinne, T.; Arias-Penna, T. & Leponce, M. (2013): Effect of rainfall exclusion on ant assemblages in montane rainforests of Ecuador. Basic and Applied Ecology 14(4), 357 - 365.
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DOI: 10.1016/j.baae.2013.04.002
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Abstract:
Abstract:
Models of global climate change generally predict higher rainfall variability, with more intense rainfall events separated by extended dry periods. We experimentally studied the effects of prolonged droughts on diverse ant assemblages found at three elevations in an Ecuadorian montane rainforest. We hypothesized that most species will be negatively affected directly (physiological stress) or indirectly (less food or suitable nesting resources) by drought. We thus expected a decrease in species richness as well as changes in assemblage composition. As the decrease of moisture content was expected to be more marked above ground than in soil, its impact on ants should differ according to their nesting site (dead wood, leaf litter, soil). After 6-month treatments, dead wood, leaf litter and soil samples were on average 53%, 46% and 4% drier under tents than controls, respectively. The drought did not alter overall species richness in the three nesting situations. However, species composition was significantly modified, mostly in dead wood and in leaf litter. Camponotus in dead wood, Strumigenys in leaf litter and Solenopsis in all three microhabitats were more abundant under tents. In contrast, Pheidole in dead wood, and Pachycondyla in leaf litter, were less abundant than in controls. Similar trends were observed at the three study sites. To conclude, after 6-month droughts dominant ant genera in the assemblages were affected differently. In the longer term, alteration of the rainfall regime is therefore expected to have an important impact on ants, as well as on their ecosystem functions and services, through shifts in species dominance and composition.
Zusammenfassung
Die Modelle des globalen Klimawandels prognostizieren im Allgemeinen variablere Niederschläge mit intensiveren Regenfällen, denen ausgedehnte Trockenperioden folgen. Wir untersuchten experimentell die Auswirkungen von längeren Trockenphasen auf verschiedene Ameisengemeinschaften auf drei Höhenstufen im Bergregenwald von Ecuador. Wir stellten die Hypothese auf, dass Trockenheit sich auf die meisten Arten negativ auswirken würde, sei es direkt (physiologischer Stress) oder indirekt (weniger Futter oder geeignetes Nistmaterial). Wir erwarteten daher eine Abnahme des Artenreichtums sowie Veränderungen in der Zusammensetzung der Arten. Da zu erwarten war, dass die Abnahme der Feuchtigkeit über dem Boden deutlicher sein würde als im Boden, sollten die Auswirkungen auf Ameisen je nach Nistplatz (Totholz, Laub, Erdreich) verschieden sein. Nach sechsmonatiger Behandlung waren die Totholz-, Laub und Erdproben unter den Abdeck-Zelten jeweils durchschnittlich 53%, 46% und 4% trockener als an den Kontrollpunkten. Die Trockenheit hat den Artenreichtum insgesamt in den drei Nist-Situationen nicht verändert. Die Zusammensetzung der Arten hatte sich jedoch signifikant verändert, vor allem in Totholz und Laub. Camponotus in Totholz, Strumigenys in Laub und Solenopsis in allen drei Mikrohabitaten waren unter den Zelten häufiger. Andererseits waren Pheidole in Totholz sowie Pachycondyla in Laub weniger häufig als auf den Kontrollflächen. Ähnliche Tendenzen wurden an allen drei untersuchten Orten beobachtet. Zusammenfassend lässt sich sagen, dass die dominanten Ameisengattungen nach sechsmonatigen Trockenphasen unterschiedlich betroffen waren. Langfristig ist daher zu erwarten, dass eine Veränderung der Niederschlagsmuster durch Veränderungen in der Arten-Dominanz und –zusammensetzung wichtige Auswirkungen auf Ameisen hat, sowie auf ihre Funktionen und Dienste im Ökosystem.
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Keywords: |
Climate change |
Elevational gradient |
Formicidae |
Rainfall manipulation |
Precipitation |
Urgiles , N.; Struß, A.; Loján Amijos, P. & Schüßler, A. (2014): Cultured arbuscular mycorrhizal fungi and native soil inocula improve seedling development of two pioneer trees in the Andean region. New Forests 45, 859–874.
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DOI: 10.1007/s11056-014-9442-8
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Abstract:
The tree species Alnus acuminata and Morella pubescens, native to South America, are candidates for soil quality improvement and afforestation of degraded areas and may serve as nurse trees for later inter-planting of other trees, including native crop trees. Both species not only form symbioses with arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF), but also with N2-fixing actinobacteria. Because tree seedlings inoculated with appropriate mycorrhizal fungi in the nursery resist transplanting stress better than non-mycorrhizal seedlings, we evaluated for A. acuminata and M. pubescens the potential of inoculation with mycorrhizal fungi for obtaining robust tree seedlings. For the first time, a laboratory-produced mixed AMF inoculum was tested in comparison with native soil from stands of both tree species, which contains AMF and EMF. Seedlings of both tree species reacted positively to both types of inocula and showed an increase in height, root collar diameter and above- and belowground biomass production, although mycorrhizal root colonization was rather low in M. pubescens. After 6 months, biomass was significantly higher for all mycorrhizal treatments when compared to control treatments, whereas aboveground biomass was approximately doubled for most treatments. To test whether mycorrhiza formation positively influences plant performance under reduced water supply the experiment was conducted under two irrigation regimes. There was no strong response to different levels of watering. Overall, application of native soil inoculum improved growth most. It contained sufficient AMF propagules but potentially also other soil microorganisms that synergistically enhance plant growth performance. However, the AMF inoculum pot-produced under controlled conditions was an efficient alternative for better management of A. acuminata and M. pubescens in the nursery, which in the future may be combined with defined EMF and Frankia inocula for improved management practices.
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Keywords: |
Ecuador |
reforestation |
AM fungi |
Arbuscular mycorrhizal fungi |
Native soil inoculum |
Pioneer trees |
Seedling growth promotion |
Schüßler, A.; Krüger, C. & Urgiles , N. (2016): Phylogenetically diverse AM fungi from Ecuador strongly improve seedling growth of native potential crop trees. Mycorrhiza 26(3), 199--207.
Orellana-Alvear, J.; Celleri, R.; Rollenbeck, R.; Muñoz, P.; Contreras, P. & Bendix, J. (2020): Assessment of Native Radar Reflectivity and Radar Rainfall Estimates for Discharge Forecasting in Mountain Catchments with a Random Forest Model. Remote Sensing 12(12), 1.
Wallis, C.; Homeier, J.; Pena Tamayo, J.E.; Brandl, R.; Farwig, N. & Bendix, J. (2019): Modeling tropical montane forest biomass, productivity and canopy traits with multispectral remote sensing data. Remote Sensing of Environment 225, 77 - 92.
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DOI: 10.1016/j.rse.2019.02.021
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Abstract:
Abstract:
Tropical montane forests, particularly Andean rainforest, are important ecosystems for regional carbon and water cycles as well as for biological diversity and speciation. Owing to their remoteness, however, ecological key-processes are less understood as in the tropical lowlands. Remote sensing allows modeling of variables related to spatial patterns of carbon stocks and fluxes (e.g., biomass) and ecosystem functioning (e.g., functional leaf traits). However, at a landscape scale most studies conducted so far are based on airborne remote sensing data which is often available only locally and for one time-point. In contrast, multispectral satellites at moderate spectral and spatial resolutions are able to provide spatially continuous and repeated observations. Here, we investigated the effectiveness of Landsat-8 imagery in modeling tropical montane forest biomass, its productivity and selected canopy traits. Topographical, spectral and textural metrics were derived as predictors. To train and validate the models, in-situ data was sampled in 54 permanent plots in forests of southern Ecuador distributed within three study sites at 1000 m, 2000 m and 3000 m a.s.l. We used partial least squares regressions to model and map all response variables. Along the whole elevation gradient biomass and productivity models explained 31%, 43%, 69% and 63% of variance in aboveground biomass, annual wood production, fine litter production and aboveground net primary production, respectively. Regression models of canopy traits measured as community weighted means explained 62%, 78%, 65% and 65% of variance in leaf toughness, specific leaf area, foliar N concentration, and foliar P concentration, respectively. Models at single study sites hardly explained variation in aboveground biomass and the annual wood production indicating that these measures are mainly determined by the change of forest types along with elevation. In contrast, the models of fine litter production and canopy traits explained between 8%–85% in variation depending on the study site. We found spectral metrics, in particular a vegetation index using the red and the green band to provide complementary information to topographical metrics. The model performances for estimating leaf toughness, biochemical canopy traits and related fine litter production all improved when adding spectral information. Our findings therefore revealed that differences in fine litter production and canopy traits in our study area are driven by local changes in vegetation edaphically induced by topography. We conclude that Landsat-derived metrics are useful in modeling fine litter production and biochemical canopy traits, in a topographically and ecologically complex tropical montane forest.
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Keywords: |
Ecuador |
Aboveground forest productivity |
Ecosystem process |
Fine litter production |
Foliar N |
Foliar P |
Grey level co-occurrence texture |
Landsat-8 |
Leaf toughness |
Specific leaf area |
Annual wood production |
Astudillo Webster, P.X.; Grass, I.; Siddons, D.; schabo, D. & Farwig, N. (2020): Centrality in species-habitat networks reveals the importance of habitat quality for high-andeans birds in Polylepis woodlands. Ardeola 67(2), 307-324.
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DOI: 10.13157/arla.67.2.2020.ra5
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Abstract:
Abstract:
Habitat loss and landscape fragmentation are important drivers of changes in biodiversity. In fragmented landscapes, bird species are able to use multiple forest patches that may therefore share an important portion of the regional biodiversity. In turn, these patches are linked through their shared bird diversity (i.e. species-habitat networks). Identifying the importance of nodes (e.g. forest patches) in species-habitat networks is increasingly important to improve conservation planning. within this network approach, the relative importance of patches for birds can be identified via centrality indices-measures of the magnitude of shared bird diversity of patches across the entire network (i.e. patch centrality). here, we tested for changes in patch centrality within bird species-patch networks of two habitat guilds, forest specialists and generalists, in relation to patch area, patch shape irregularity and within-patch habitat characteristics across 15 Polylepis woodland patches in a páramo landscape of southern Ecuador. Patch centrality for forest specialists decreased with greater influence of surrounding páramo plants, i.e. an increasing proportion of bunch-grasses and small shrubs, in the within-patch habitat and was unaffected by either patch area or patch shape irregularity. On the other hand, patch centrality for generalists was positively influenced by patch shape irregularity but was unaffected by
patch area or the influence of surrounding páramo plants in the within-patch habitat. Patch centrality reveals that the relative importance of Polylepis woodlands lies in their habitat quality. Forest specialists are dependent on mature Polylepis woodland patches, while generalists benefit from the natural irregular shape of the woodlands. Finally, a species-habitat network approach facilitates the recognition of important Polylepis patches and their characteristics for conservation of the Andean bird communityat a landscape scale.
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Keywords: |
Ecuador |
Paramo |
Tropical Andes |
forest specialist |
habitat guild |
Duenas, J.F.; Camenzind, T.; Roy, J.; Hempel, S.; Homeier, J.; Suarez, J.P. & Rillig, M.C. (2020): Moderate phosphorus additions consistently affect community composition of arbuscular mycorrhizal fungi in tropical montane forests in southern Ecuador. New Phytologist 227, 1505-1518.
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DOI: 10.1111/NPH.16641
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Abstract:
Abstract:
Anthropogenic atmospheric deposition can increase nutrient supply in the most remote ecosystems, potentially affecting soil biodiversity. Arbuscular mycorrhizal fungal (AMF) communities rapidly respond to simulated soil eutrophication in tropical forests. Yet the
limited spatio-temporal extent of such manipulations, together with the often unrealistically high fertilization rates employed, impedes generalization of such responses.
We sequenced mixed root AMF communities within a seven year-long fully factorial nitrogen (N) and phosphorus (P) addition experiment, replicated at three tropical montane forests in southern Ecuador with differing environmental characteristics. We hypothesized
(i) strong shifts in community composition and species richness after long-term fertilization, (ii) site- and (iii) clade-specific responses to N versus P additions depending on local soil fertility and clade life history traits respectively.
Fertilization consistently shifted AMF community composition across sites, but only reduced richness of Glomeraceae. Compositional changes were mainly driven by increases in P supply while richness reductions were observed only after combined N and P additions.
We conclude that moderate increases of N and P exert a mild but consistent effect on tropical AMF communities. To predict the consequences of these shifts, current results need to be supplemented with experiments that characterize local species-specific AMF
functionality.
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Keywords: |
NUMEX |
San Francisco |
Bombuscaro |
Cajanuma |
Nutrient deposition |
Arbuscular mycorrhizal fungi |
Malizia, A.; Blundo, C.; Carilla, J.; Osinaga Acosta, O.; Cuesta, F.; Duque, A.; Aguirre, N.; Aguirre, Z.; Ataroff, M.; Baez, S.; Calderon-Loor, M.; Cayola, L.; Cayuela, L.; Ceballos, S.; Cedillo, H.; Farfan-Rios, W.; Feeley, K.; Fuentes, A.; Gamez-Avarez, L.; Grau, R.; Homeier, J.; Jadan, O.; Llambi, L.; Loza-Rivera, M.; Macia, M.; Malhi, Y.; Malizia, L.; Peralvo, M.; Pinto, E.; Tello, S.; Silman, M. & Young, K. (2020): Elevation and latitude drives structure and tree species composition in Andean forests: Results from a large-scale plot network. PLoS One 15(4), e0231553.
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DOI: 10.1371/journal.pone.0231553
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Abstract:
Abstract:
Our knowledge about the structure and function of Andean forests at regional scales remains limited. Current initiatives to study forests over continental or global scales still have important geographical gaps, particularly in regions such as the tropical and subtropical Andes. In this study, we assessed patterns of structure and tree species diversity along ~ 4000 km of latitude and ~ 4000 m of elevation range in Andean forests. We used the Andean Forest Network (Red de Bosques Andinos, https://redbosques.condesan.org/) database which, at present, includes 491 forest plots (totaling 156.3 ha, ranging from 0.01 to
6 ha) representing a total of 86,964 identified tree stems � 10 cm diameter at breast height belonging to 2341 identified species, 584 genera and 133 botanical families. Tree stem density and basal area increases with elevation while species richness decreases. Stem
density and species richness both decrease with latitude. Subtropical forests have distinct tree species composition compared to those in the tropical region. In addition, floristic similarity of subtropical plots is between 13 to 16% while similarity between tropical forest plots
is between 3% to 9%. Overall, plots ~ 0.5-ha or larger may be preferred for describing patterns at regional scales in order to avoid plot size effects. We highlight the need to promote collaboration and capacity building among researchers in the Andean region (i.e., South-South cooperation) in order to generate and synthesize information at regional scale.
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Keywords: |
forest structure |
tree species richness |
tree species |
Tropical Andes |
Freis, M. (2019): Der Einfluss von Stickstoff- und/oder Phosphatdüngung auf Blatteigenschaften und Herbivorie an holzigen Jungpflanzen in tropischen Bergwäldern Südecuadors University of Goettingen, bachelor thesis
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Abstract:
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The anthropogenic deposition of nitrogen (N) and phosphorus (P) into terrestrial ecosystems has an influence on the leaf morphology and leaf properties of vegetation as well as on interactions within an ecosystem. In this context, the increased availability of nutrients has an impact on herbivory. In addition to the availability of nutrients, sea level has also been shown to influence these parameters. The shown work deals with the quantification of herbivory under the influence of N- and P-fertilization and differences in certain leaf parameters (leaf area, specific leaf area, leaf toughness, leaf nitrogen content and leaf area loss) between three altitudinal levels (1000 m, 2000 m, 3000 m). The study area was located in a tropical mountain rainforest in Southern Ecuador. In a nutrient manipulation experiment (NUMEX) 48 plots within the study areas were fertilized with either N, P or NP twice a year. Per plot 50 leaves were collected, examined for various parameters and then subjected to a nutrient analysis. The aim of this study was to figure out to what extent sea level influences the leaf morphology, nitrogen content and the leaf area loss of the vegetation within the control areas and to what extent fertilization with nitrogen, phosphorus or both elements changes these leaf properties. Finally, it was investigated whether possible changes in feeding rates resulted from an increased leaf nitrogen content. Sea level had a major influence on leaf strength, which increased with increasing height gradients, and on the specific leaf area and the mean leaf area, which decreased with increasing sea level. Many of the values differed significantly between the altitudinal levels. This suggests that not only the soil becomes nutrient-poorer with rising sea level, but also that the mineralisation of the few available nutrients is slower than at lower altitudes. The climatic environmental conditions, which become more extreme as the sea level rises, also explain the changes in the leaf parameters mentioned. Fertilisation instead did not have an influence as strong as sea level on the studied parameters. There were hardly any significant differences between the plots with different fertilisation. Since tropical forests are considered nutrient-limited, the addition of nitrogen led to the formation of large and soft leaves, which was expected. The correlations between leaf nitrogen content and SLA or leaf strength were positive and significant. Leaf area loss did not correlate with nitrogen content, which was unexpected. This can be attributed to the fact that plants show highly species-specific reactions to nutrient availability, which manifest themselves in very different plastic changes in growth and defence mechanisms against herbivore species. In this work a strong influence of the sea level on the leaf parameters could be determined. An increasing influence of fertilization on the feeding rate of herbivorous species was not found.
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Keywords: |
seedlings |
NUMEX |
San Francisco |
Bombuscaro |
Cajanuma |
herbivory |
leaf properties |
Happ, J. (2019): The influence of phosphorus and nitrogen addition on leaf properties of herbaceous plants in tropical montane rainforests in southern Ecuador University of Goettingen, bachelor thesis
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The tropical Andes are one of the most biodiverse hotspots on earth. Though the nutrient-limited systems are affected by anthropogenic nutrient inputs due to industry and agriculture. The NuMEx (Nutrient Manipulation Experiment) project, which was set up in 2008 and is located in southern Ecuador and aims to find out about the consequences of nutrient pollution to herbivore and plant interaction. Therefore experimental plots at three different levels of elevation were fertilised with nitrogen and phosphorus. In this study, fresh leaf samples were collected in May 2018. Plant parameters like leaf area, specific leaf area, leaf toughness and nitrogen content were analysed. Herbivory was examined trough leaf area loss measurements. Changes in these parameters along an elevation gradient from 1000 to 3000 m were analysed. Moreover, the study focussed on the influence of the nutrient addition to the sensible tropical system.
A significant influence of the elevation on most of the leaf morphology parameters was shown. Specific leaf area and leaf nitrogen content showed a significant decrease along the elevation gradient, while the leaves became tougher. The mean leaf area and the leaf area loss gained no significant results; however, the leaf area tended to be smaller within rising elevation. The leaf area loss was highest at 3000 m of elevation. All elevation outcomes, except for the leaf area loss, could be explained by the harsher climatic conditions at higher elevation levels and the relationship between nitrogen content and the leaf traits.
Nutrient addition results on the leaf traits were less clear. Almost no significant influences could be measured. The leaf characteristics showed mostly a clear trend though, except for the leaf area. The leaf area partially increased (mostly under mixed nitrogen and phosphorus addition) and partially decreased (nitrogen treatment) due to the nutrient addition. Specific leaf area, leaf nitrogen content and leaf area loss mostly increased due to the nutrient addition, especially nitrogen and the mixed nitrogen and phosphorus sample contributed to the increase. Leaf toughness whereas decreased. The highest decrease was caused at the plots treated with the nitrogen and phosphorus mix. The results make clear that a high leaf nitrogen content correlates with soft leaves and a high specific leaf area. An analysis of the leaf area loss and the leaf nitrogen content yielded that also these traits are correlated.
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Keywords: |
NUMEX |
San Francisco |
Bombuscaro |
Cajanuma |
herbivory |
leaf properties |
Wilcke, W.; Velescu, A.; Leimer, S. & Valarezo, C. (2020): Water and Nutrient Budgets of Organic Layers and Mineral Topsoils Under Tropical Montane Forest in Ecuador in Response to 15 Years of Environmental Change. In: Levia, D., Carlyle-Moses, D., Iida, S., Michalzik, B., Nanko, K., Tischer, A. (eds.): Forest-Water Interactions (Ecological Studies 240), Springer, Cham, 565-586.
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DOI: 10.1007/978-3-030-26086-6_23
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Abstract:
Abstract:
We quantified the changes in macronutrient storages of the soil in a remote Andean tropical montane rain forest on the rim of the Amazon basin from 1998 to 2013. In the studied 15 years, the N, P, and S fluxes in throughfall+stemflow increased significantly, while those of Ca decreased and of Mg and K remained unchanged. The main reasons for increasing nutrient inputs were Amazonian forest fires. Ca inputs decreased because of a particularly strong Sahara dust deposition event in 1999/2000. On average of the 15 budgeted years, P and K accumulated in the organic layer at a rate doubling their current storages in 197 and 27 years, respectively. The other macronutrients were on average leached from the organic layer, depleting it in 38 (Mg) to 281 years (N). Nutrient leaching was likely favored by enhanced mineralization driven by climate warming. In the upper 30 cm of the mineral soil, all macronutrients accumulated at rates doubling their storages in 57 (Ca) to 601 years (P). Our results demonstrate that the current environmental change increased the nutrient supply of the studied ecosystem. Increased nutrient supply might shift the ecosystem to a new state and change the chemistry of headwater streams.
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Keywords: |
nitrogen |
phosphorus |
environmental change |
macronutrients |
nutrient storage |
base metals |
sulfur |
Knoke, T.; Paul, C.; Rammig, A.; Gosling, E.; Hildebrandt, P.; Härtl, F.; Peters, T.; Richter, M.; Diertl, K.; Castro, L.M.; Calvas, B.; Ochoa Moreno, S.; Valle-Carrión, L.A.; Hamer, U.; Tischer, A.; Potthast, K.; Windhorst, D.; Homeier, J.; Wilcke, W.; Velescu, A.; Gerique, A.; Pohle, P.; Adams, J.; Breuer, L.; Mosandl, R.; Beck, E.; Weber, M.; Stimm, B.; Silva, B.; Verburg, P.H. & Bendix, J. (2020): Accounting for multiple ecosystem services in a simulation of land-use decisions: Does it reduce tropical deforestation?. Global Change Biology 26( ), 1-22.
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DOI: 10.1111/gcb.15003
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Abstract:
Abstract:
Abstract Conversion of tropical forests is among the primary causes of global environmental change. The loss of their important environmental services has prompted calls to integrate ecosystem services (ES) in addition to socio-economic objectives in decision-making. To test the effect of accounting for both ES and socio-economic objectives in land-use decisions, we develop a new dynamic approach to model deforestation scenarios for tropical mountain forests. We integrate multi-objective optimization of land allocation with an innovative approach to consider uncertainty spaces for each objective. These uncertainty spaces account for potential variability among decision-makers, who may have different expectations about the future. When optimizing only socio-economic objectives, the model continues the past trend in deforestation (1975–2015) in the projected land-use allocation (2015–2070). Based on indicators for biomass production, carbon storage, climate and water regulation, and soil quality, we show that considering multiple ES in addition to the socio-economic objectives has heterogeneous effects on land-use allocation. It saves some natural forest if the natural forest share is below 38%, and can stop deforestation once the natural forest share drops below 10%. For landscapes with high shares of forest (38%–80% in our study), accounting for multiple ES under high uncertainty of their indicators may, however, accelerate deforestation. For such multifunctional landscapes, two main effects prevail: (a) accelerated expansion of diversified non-natural areas to elevate the levels of the indicators and (b) increased landscape diversification to maintain multiple ES, reducing the proportion of natural forest. Only when accounting for vascular plant species richness as an explicit objective in the optimization, deforestation was consistently reduced. Aiming for multifunctional landscapes may therefore conflict with the aim of reducing deforestation, which we can quantify here for the first time. Our findings are relevant for identifying types of landscapes where this conflict may arise and to better align respective policies.
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Keywords: |
Ecuador |
biodiversity |
ecosystem services |
landscape restoration |
land allocation |
robust optimization |
Beck, E.; Paladines, P.; Paladines, R.; Matt, F.; Farwig, N. & Bendix, J. (2019): Alexander von Humboldt would have loved it: Estación Científica San Francisco.. Ecotropica 21, 201 99.
Dugger, P.; Blendinger, P.; Boehning-Gaese, K.; Chama, L.; Correia, M.; Dehling, D.; Emer, C.; Farwig, N.; Fricke, E.; Galetti, M.; Garcia, D.; Grass, I.; Heleno, R.; Jacomassa, F.; Morales, S.; Moran, C.; Munoz, M.; Neuschulz, E.; Nowak, L.; Piratelli, A.; Pizo, M.; Quitian, M.; Rogers, H.; Ruggera, R.; Saveedra, F.; Sanchez, M.; Sanchez, R.; Santillan, V.; schabo, D.; Ribeiro da Silva, F.; Timoteo, S.; Traveset, A.; Vollstaedt, M. & Schleuning, M. (2019): Seed‐dispersal networks are more specialized in the Neotropics than in the Afrotropics. Global Ecology and Biogeography 28(2), 248-261.
Santillan, V.; Quitian, M.; Tinoco, B.A.; Zarate, E.; Schleuning, M.; Boehning-Gaese, K. & Neuschulz, E. (2019): Direct and indirect effects of elevation, climate and vegetation structure on bird communities on a tropical mountain. Acta Oecologica 102, 103500.
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DOI: 10.1016/j.actao.2019.103500
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Abstract:
Abstract:
Climate and vegetation structure are important predictors of biodiversity along mountain slopes. The drivers of elevational biodiversity gradients are not yet fully resolved. For instance, there is little understanding of how direct and indirect effects of elevation shape species communities along mountain slopes. In this study, we identify the main drivers of bird diversity along an elevational gradient spanning 2000 m in the Ecuadorian Andes. We simultaneously tested the direct and indirect effects of elevation, temperature, precipitation and vegetation structure on overall bird diversity and on frugivorous and insectivorous birds, using structural equation models (SEMs). We found that elevation was mostly indirectly associated with bird diversity, mediated via abiotic (i.e., temperature, precipitation) and biotic (i.e., vegetation structure) factors. We found consistent positive effects of temperature and vegetation structure and negative effects of precipitation on overall bird diversity and on frugivorous and insectivorous birds. In addition, elevation was directly, positively associated with insectivore richness and abundance, but not with that of frugivores. Our results show that climatic factors and vegetation structure jointly shape the richness of bird communities on tropical mountains. However, other factors, such as biotic interactions or different evolutionary histories of lowland and highland communities, may additionally contribute to elevational patterns in bird diversity. Thus, species communities across tropical mountain slopes are shaped by a multitude of abiotic and biotic factors that need to be studied simultaneously for a mechanistic understanding of patterns in biodiversity.
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Keywords: |
avian diversity patterns |
Schleuning, M.; Neuschulz, E.; Albrecht, J.; Bender, I.M.; Bowler, D.; Dehling, D.; Fritz, S.; Hof, C.; Mueller, T.; Nowak, L.; Sorensen, M.; Boehning-Gaese, K. & Kissling, W. (2020): Trait-Based Assessments of Climate-Change Impacts on Interacting Species. Trends in Ecology and Evolution xxx-xxx, xxx-xxx.
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DOI: 10.1016/j.tree.2019.12.010
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Abstract:
Abstract:
Plant–animal interactions are fundamentally important in ecosystems, but have often been ignored by studies of climate-change impacts on biodiversity. Here, we present a trait-based framework for predicting the responses of interacting plants and animals to climate change. We distinguish three pathways along which climate change can impact interacting species in ecological communities: (i) spatial and temporal mismatches in the occurrence and abundance of species, (ii) the formation of novel interactions and secondary extinctions, and (iii) alterations of the dispersal ability of plants. These pathways are mediated by three kinds of functional traits: response traits, matching traits, and dispersal traits. We propose that incorporating these traits into predictive models will improve assessments of the responses of interacting species to climate change.
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Keywords: |
plants |
functional traits |
global change |
animals |
ecological networks |
dispersal |
DFG FOR2730 - RESPECT (2020): Tabebuia Bulletin, Issue 7. Laboratory for Climatology and Remote Sensing (LCRS), University of Marburg, Marburg, Germany.
Seidel, J.; Trachte, K.; Orellana-Alvear, J.; Figueroa, R.; Celleri, R.; Bendix, J.; Fernandez, C. & Huggel, C. (2019): Precipitation Characteristics at Two Locations in the Tropical Andes by Means of Vertically Pointing Micro-Rain Radar Observations. Remote Sensing 11(24), 2985.
Bogner, F.; Bendix, J. & Beck, E. 2019: El Bosque Tropical de Montaña - Hotspot de Biodiversidad. (Naturaleza y Cultura Internacional, (Loja, Ecuador).
Quichimbo Miguitama, P.G.; Jiménez, L.S.; Veintimilla, D.; Potthast, K.; Tischer, A.; Günter, S.; Mosandl, R. & Hamer, U. (2019): Nutrient dynamics in an Andean forest region: a case study of exotic and native species plantations in southern Ecuador. New Forests -, 1 - 22.
Haug, I.; Setaro, S. & Suarez, J.P. (2019): Species composition of arbuscular mycorrhizal communities changes with elevation in the Andes of South Ecuador. PLOS ONE 14(8), 1-19.
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DOI: 10.1371/journal.pone.0221091
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Abstract:
Abstract:
Arbuscular mycorrhizal fungi (AMF) are the most prominent mycobionts of plants in the tropics, yet little is known about their diversity, species compositions and factors driving AMF distribution patterns. To investigate whether elevation and associated vegetation type affect species composition, we sampled 646 mycorrhizal samples in locations between 1000 and 4000 m above sea level (masl) in the South of Ecuador. We estimated diversity, distribution and species compositions of AMF by cloning and Sanger sequencing the 18S rDNA (the section between AML1 and AML2) and subsequent derivation of fungal OTUs based on 99% sequence similarity. In addition, we analyzed the phylogenetic structure of the sites by computing the mean pairwise distance (MPD) and the mean nearest taxon difference (MNTD) for each elevation level. It revealed that AMF species compositions at 1000 and 2000 masl differ from 3000 and 4000 masl. Lower elevations (1000 and 2000 masl) were dominated by members of Glomeraceae, whereas Acaulosporaceae were more abundant in higher elevations (3000 and 4000 masl). Ordination of OTUs with respect to study sites revealed a correlation to elevation with a continuous turnover of species from lower to higher elevations. Most of the abundant OTUs are not endemic to South Ecuador. We also found a high proportion of rare OTUs at all elevations: 79–85% of OTUs occurred in less than 5% of the samples. Phylogenetic community analysis indicated clustering and evenness for most elevation levels indicating that both, stochastic processes and habitat filtering are driving factors of AMF community compositions.
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Keywords: |
species |
arbuscular mycorrhiza |
Andes |
Arbuscular mycorrhizal fungi |
Orellana-Alvear, J.; Celleri, R.; Rollenbeck, R. & Bendix, J. (2019): Optimization of X-Band Radar Rainfall Retrieval in the Southern Andes of Ecuador Using a Random Forest Model. Remote Sensing 11(14), 1632.
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DOI: 10.3390/rs11141632
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Abstract:
Abstract:
Despite many eorts of the radar community, quantitative precipitation estimation (QPE)
from weather radar data remains a challenging topic. The high resolution of X-band radar imagery
in space and time comes with an intricate correction process of reflectivity. The steep and high
mountain topography of the Andes enhances its complexity. This study aims to optimize the rainfall
derivation of the highest X-band radar in the world (4450 m a.s.l.) by using a random forest (RF)
model and single Plan Position Indicator (PPI) scans. The performance of the RFmodel was evaluated
in comparison with the traditional step-wise approach by using both, the Marshall-Palmer and a
site-specific Z–R relationship. Since rain gauge networks are frequently unevenly distributed and
hardly available at real time in mountain regions, bias adjustment was neglected. Results showed an
improvement in the step-wise approach by using the site-specific (instead of the Marshall-Palmer)
Z–R relationship. However, both models highly underestimate the rainfall rate (correlation coecient
< 0.69; slope up to 12). Contrary, the RF model greatly outperformed the step-wise approach in
all testing locations and on dierent rainfall events (correlation coecient up to 0.83; slope = 1.04).
The results are promising and unveil a dierent approach to overcome the high attenuation issues
inherent to X-band radars.
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Keywords: |
South Ecuador |
random forest |
radar |
calibration |
Cajas National Park |
Wilcke, W.; Velescu, A.; Leimer, S.; Bigalke, M.; Boy, J. & Valarezo, C. (2019): Temporal Trends of Phosphorus Cycling in a Tropical Montane Forest in Ecuador During 14 Years. Journal of Geophysical Research: Biogeosciences 124, 1370-1386.
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DOI: 10.1029/2018JG004942
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Abstract:
Abstract:
Increased bioavailability of P can have a negative impact on plant biodiversity. In an approximately 9‐ha catchment under N + P‐limited megadiverse tropical montane forest in Ecuador, we budgeted all major P fluxes and determined whether the P fluxes changed from 1999 to 2013. Furthermore, we assessed which external drivers (rainfall, total P and acid deposition) caused this potential change. Mean (±SD) annual P deposition (bulk+dry) was 240 ± 270 mg/m2, with the SD reflecting the interannual variation. The annual P flux to the soil via throughfall+stemflow+litterfall was 1,400 ± 170 mg/m2 of which 18 ± 9.2% was leached to below the organic layer. The mineral soil retained 80 ± 12% of the P leached from the organic layer. The mean annual P weathering rate was 79 ± 63 mg/m2. The sum of P fluxes was approximately 5 times larger above than below the mineral soil surface, illustrating that P was tightly cycled in the biological part of the forest. The mean annual canopy budget was negative (−120 ± 280 mg/m2); that is, P was leached from the canopy. Throughfall was the largest source of dissolved P. The P catchment budget (total deposition‐streamflow) was positive (200 ± 270 mg/m2); that is, P was retained, mainly in the soil organic layer. From 1999 to 2013, P fluxes with throughfall, stemflow, and streamflow increased significantly. The strongest driver of the P budgets of the canopy and the catchment was total P deposition. Our results demonstrate that mainly biological processes retained deposited P in the vegetation and the organic layer enhancing the internal P cycle.
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Keywords: |
litterfall |
temporal trends |
catchment budget |
weathering rates |
phosphorus fluxes |
González-Jaramillo, V.; Fries, A. & Bendix, J. (2019): AGB Estimation in a Tropical Mountain Forest (TMF) by Means of RGB and Multispectral Images Using an Unmanned Aerial Vehicle (UAV). Remote Sensing 11(12), 1-22.
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DOI: 10.3390/rs11121413
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Abstract:
Abstract:
The present investigation evaluates the accuracy of estimating above-ground biomass (AGB)
by means of two dierent sensors installed onboard an unmanned aerial vehicle (UAV) platform
(DJI Inspire I) because the high costs of very high-resolution imagery provided by satellites or light
detection and ranging (LiDAR) sensors often impede AGB estimation and the determination of
other vegetation parameters. The sensors utilized included an RGB camera (ZENMUSE X3) and a
multispectral camera (Parrot Sequoia), whose images were used for AGB estimation in a natural
tropical mountain forest (TMF) in Southern Ecuador. The total area covered by the sensors included
80 ha at lower elevations characterized by a fast-changing topography and dierent vegetation covers.
From the total area, a core study site of 24 ha was selected for AGB calculation, applying two dierent
methods. The firstmethod used the RGB images and applied the structure formotion (SfM) process to
generate point clouds for a subsequent individual tree classification. Per the classification at tree level,
tree height (H) and diameter at breast height (DBH) could be determined, which are necessary input
parameters to calculate AGB (Mg ha 1) by means of a specific allometric equation for wet forests.
The second method used the multispectral images to calculate the normalized dierence vegetation
index (NDVI), which is the basis for AGB estimation applying an equation for tropical evergreen
forests. The obtained results were validated against a previous AGB estimation for the same area
using LiDAR data. The study found two major results: (i) The NDVI-based AGB estimates obtained
by multispectral drone imagery were less accurate due to the saturation eect in dense tropical forests,
(ii) the photogrammetric approach using RGB images provided reliable AGB estimates comparable
to expensive LiDAR surveys (R2: 0.85). However, the latter is only possible if an auxiliary digital
terrain model (DTM) in very high resolution is available because in dense natural forests the terrain
surface (DTM) is hardly detectable by passive sensors due to the canopy layer, which impedes
ground detection.
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Keywords: |
Ecuador |
mountain rainforest |
UAV |
Biomass |
Drone |
Guallpa, M.; Orellana-Alvear, J. & Bendix, J. (2019): Tropical Andes Radar Precipitation Estimates Need High Temporal and Moderate Spatial Resolution. Water 11(5), 1-22.
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DOI: 10.3390/w11051038
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Abstract:
Abstract:
Weather radar networks are an excellent tool for quantitative precipitation estimation
(QPE), due to their high resolution in space and time, particularly in remote mountain areas such as
the Tropical Andes. Nevertheless, reduction of the temporal and spatial resolution might severely
reduce the quality of QPE. Thus, the main objective of this study was to analyze the impact of spatial
and temporal resolutions of radar data on the cumulative QPE. For this, data from the world’s highest
X-band weather radar (4450 m a.s.l.), located in the Andes of Ecuador (Paute River basin), and from
a rain gauge network were used. Dierent time resolutions (1, 5, 10, 15, 20, 30, and 60 min) and
spatial resolutions (0.5, 0.25, and 0.1 km) were evaluated. An optical flow method was validated
for 11 rainfall events (with dierent features) and applied to enhance the temporal resolution of
radar data to 1-min intervals. The results show that 1-min temporal resolution images are able to
capture rain event features in detail. The radar–rain gauge correlation decreases considerably when
the time resolution increases (r from 0.69 to 0.31, time resolution from 1 to 60 min). No significant
dierence was found in the rain total volume (3%) calculated with the three spatial resolution data.
A spatial resolution of 0.5 km on radar imagery is suitable to quantify rainfall in the AndesMountains.
This study improves knowledge on rainfall spatial distribution in the Ecuadorian Andes, and it will
be the basis for future hydrometeorological studies
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Keywords: |
Cuenca |
radar |
rainfall |
Paute |
Graefe, S.; Fang, D. & Butz, P. (2019): Water residence times in trees of a neotropical dry forest. Trees 1, 1–7.
Butz, P.; Hölscher, D.; Cueva, E. & Graefe, S. (2018): Tree Water Use Patterns as Influenced by Phenology in a Dry Forest of Southern Ecuador. Frontiers in Plant Science 9, 945.
Raffelsbauer, V.; Spannl, S.; Peña , K.; Pucha Cofrep, D.A.; Steppe, K. & Bräuning, A. (2019): Tree Circumference Changes and Species-Specific Growth Recovery After Extreme Dry Events in a Montane Rainforest in Southern Ecuador. Frontiers in Plant Sciences 10, 342.
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DOI: 10.3389/fpls.2019.00342
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Abstract:
Abstract:
Under drought conditions, even tropical rainforests might turn from carbon sinks to sources, and tree species composition might be altered by increased mortality. We monitored stem diameter variations of 40 tree individuals with stem diameters above 10 cm belonging to eleven different tree genera and three tree life forms with high-resolution dendrometers from July 2007 to November 2010 and additionally March 2015 to December 2017 in a tropical mountain rainforest in South Ecuador, a biodiversity hotspot with more than 300 different tree species belonging to different functional types. Although our study area receives around 2200 mm of annual rainfall, dry spells occur regularly during so-called “Veranillo del Niño” (VdN) periods in October-November. In climate change scenarios, droughts are expected with higher frequency and intensity as today. We selected dry intervals with a minimum of four consecutive days to examine how different tree species respond to drought stress, raising the question if some species are better adapted to a possible higher frequency and increasing duration of dry periods. We analyzed the averaged species-specific stem shrinkage rates and recovery times during and after dry periods. The two deciduous broadleaved species Cedrela montana and Handroanthus chrysanthus showed the biggest stem shrinkage of up to 2 mm after 10 consecutive dry days. A comparison of daily circumference changes over 600 consecutive days revealed different drought responses between the families concerning the percentage of days with stem shrinkage/increment, ranging from 27.5 to 72.5% for Graffenrieda emarginata to 45–55% for Podocarpus oleifolius under same climate conditions. Moreover, we found great difference of recovery times after longer-lasting (i.e., eight to ten days) VdN drought events between the two evergreen broadleaved species Vismia cavanillesiana and Tapirira guianensis. While Vismia replenished to pre-VdN stem circumference after only 5 days, Tapirira needed 52 days on average to restore its circumference. Hence, a higher frequency of droughts might increase inter-species competition and species-specific mortality and might finally alter the species composition of the ecosystem.
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Keywords: |
tree growth |