Publications
Found 850 publication(s)
- of type
Castro, L.M.; Calvas, B. & Knoke, T. (2015): Ecuadorian Banana Farms Should Consider Organic Banana with Low Price Risks in Their Land-Use Portfolios. PlOS one 10(3), e0120384.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1371/journal.pone.0120384
-
Abstract:
Abstract:
Organic farming is a more environmentally friendly form of land use than conventional agriculture. However, recent studies point out production tradeoffs that often prevent the adoption of such practices by farmers. Our study shows with the example of organic banana production in Ecuador that economic tradeoffs depend much on the approach of the analysis. We test, if organic banana should be included in economic land-use portfolios, which indicate how much of the land is provided for which type of land-use. We use time series data for productivity and prices over 30 years to compute the economic return (as annualized net present value) and its volatility (with standard deviation as risk measure) for eight crops to derive land-use portfolios for different levels of risk, which maximize economic return. We find that organic banana is included in land-use portfolios for almost every level of accepted risk with proportions from 1% to maximally 32%, even if the same high uncertainty as for conventional banana is simulated for organic banana. A more realistic, lower simulated price risk increased the proportion of organic banana substantially to up to 57% and increased annual economic returns by up to US$ 187 per ha. Under an assumed integration of both markets, for organic and conventional banana, simulated by an increased coefficient of correlation of economic return from organic and conventional banana (? up to +0.7), organic banana holds significant portions in the land-use portfolios tested only, if a low price risk of organic banana is considered. We conclude that uncertainty is a key issue for the adoption of organic banana. As historic data support a low price risk for organic banana compared to conventional banana, Ecuadorian farmers should consider organic banana as an advantageous land-use option in their land-use portfolios.
-
Keywords: |
land diversification |
agriculture |
land use modeling |
Cruz, D.; Suarez, J.P.; Kottke, I. & Piepenbring, M. (2014): Cryptic species revealed by molecular phylogenetic analysis of sequences obtained from basidiomata of Tulasnella. . Mycologia 106(4), 708-722.
-
log in to download
-
link
-
view metadata
-
DOI: 10.3852/12-386
-
Abstract:
Abstract:
Delimitation of species and the search for a proper threshold for defining phylogenetic species in fungi are under discussion. In this study, morpho- logical and molecular data are correlated to delimit species of Tulasnella, the most important mycobionts of Orchidaceae, which suffer from poor taxonomy. Resupinate basidiomata of Tulasnella species were collected in Ecuador and Germany, and 11 specimens (seven from Ecuador, four from Germany) were assigned to traditional species concepts by use of morphological keys. The specimens were compared by micro-anatomical examination with 75 specimens of Tulasnella borrowed from fungaria to obtain better insights on variation of characters. Sequences of the ITS region (127) were obtained after cloning from the fresh basidiomata and from pure cultures. Proportional variability of ITS sequences was analyzed within and among the cultures and the specimens designated to different morphospecies. Results sug- gested an intragenomic variation of less than 2%, an intraspecific variation of up to 4% and an interspe- cific divergence of more than 9% in Tulasnella. Cryptic species in Tulasnella, mostly from Ecuador, were revealed by phylogenetic analyses with 4% intraspecific divergence as a minimum threshold for delimiting species. Conventional diagnostic morpho- logical characters appeared insufficient for species characterization. Arguments are presented for molec- ular delimitation of the established species Tulasnella
albida, T. asymmetrica, T. eichleriana, T. cf. pinicola, T. tomaculum and T. violea.
-
Keywords: |
interspecific divergence |
intragenomic variability |
intraspecific variability |
morphospecies |
Spöri, E. (2015): Phosphatase Activity in Soil of an Ecuadorian Tropical Montane Rainforest University of Tuebingen, bachelor thesis
-
log in to download
-
link
-
view metadata
-
Abstract:
Abstract:
Ecosystems worldwide face increasing nutrient depositions mainly caused by anthropogenic processes. In particular, tropical ecosystems react sensitively to altering nutrient supply. The deposition of nutrients might influence the nutrient cycles, primarily of N and P in tropical montane rainforests. Increased nutrient supply leads to an enhanced biomass production and therefore other nutrients become limited for plants and microorganisms.
For this reason, the aim of this thesis is to study the response of phosphatase activity (PA) on moderate fertilization along an altitudinal gradient in a tropical montane rainforest in South Ecuador. The experiment was conducted on the NUMEX study sites including three different elevation levels 1000, 2000 and 3000m a.s.l. The different plots were treated with N, P, N+P to simulate increased nutrient depositions and one control plot. Further, organic layer and mineral soil was sampled and phosphomono- and phosphodiesterase activity (PMEA and PDEA) were determined.
The N fertilized plots showed only small effects compared to the control; presumably due to low amounts of added fertilizer. PA in the P addition plots showed reduced activity compared to the control with significant results of PMEA in the organic layer of the study sites on 2000 and 3000m a.s.l. The reason might be sufficient quantities of inorganic P which suppresses the production of phosphatases. Further, PA in N+P plots showed lower PA compared to the control than in the P addition plots. This effect could be caused through the dominating inhibitory effect of P in contrast to the stimulating effect of N on PA. Altitudinal differences were observed comparing the control plots at different elevation levels (1000, 2000 and 3000m a.s.l.). The results for the organic layer showed increasing PA along the altitudinal gradient with the lowest PA at 1000m a.s.l. The findings are contrary to the present literature which states that lowland tropical forests are characterized by high decomposition rates coming up with high PA. The findings cannot support this hypothesis; therefore more research is needed in the studied area in South Ecuador.
-
Keywords: |
NUMEX |
nutrient cycle |
Matson, A.; Corre, M. & Veldkamp, E. (2014): Nitrogen cycling in canopy soils of tropical montane forests responds rapidly to indirect N and P fertilization. Global Change Biiology 20, 3802-3813.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1111/gcb.12668
-
Abstract:
Abstract:
Although the canopy can play an important role in forest nutrient cycles, canopy-based processes are often overlooked in studies on nutrient deposition. In areas of nitrogen (N) and phosphorus (P) deposition, canopy soils may retain a significant proportion of atmospheric inputs, and also receive indirect enrichment through root uptake followed by throughfall or recycling of plant litter in the canopy. We measured net and gross rates of N cycling in canopy soils of tropical montane forests along an elevation gradient and assessed indirect effects of elevated nutrient inputs to the forest floor. Net N cycling rates were measured using the buried bag method. Gross N cycling rates were measured using 15N pool dilution techniques. Measurements took place in the field, in the wet and dry season,using intact cores of canopy soil from three elevations (1000, 2000 and 3000 m). The forest floor had been fertilized biannually with moderate amounts of N and P for 4 years; treatments included control, N, P, and N + P. In control plots, gross rates of NH4+ transformations decreased with increasing elevation; gross rates of NO3- transformations
did not exhibit a clear elevation trend, but were significantly affected by season. Nutrient-addition effects were different at each elevation, but combined N + P generally increased N cycling rates at all elevations. Results showed that canopy soils could be a significant N source for epiphytes as well as contributing up to 23% of total (canopy + forest floor) mineral N production in our forests. In contrast to theories that canopy soils are decoupled from nutrient cycling in forest floor soil, N cycling in our canopy soils was sensitive to slight changes in forest floor nutrient availability.Long-term atmospheric N and P deposition may lead to increased N cycling, but also increased mineral N losses from the canopy soil system.
-
Keywords: |
NUMEX |
nitrogen |
canopy |
phosphorus |
Paul, C. & Knoke, T. (2015): Between land sharing and land sparing – what role remains for forest management and conservation?. International Forestry Review 17(2), 210-230.
-
log in to download
-
link
-
view metadata
-
Abstract:
Abstract:
Conflicts between satisfying the growing global demand for food and energy and simultaneously preserving natural ecosystems have spurred renewed debate about how to optimise future land use. This study reviews the role of forests and forest management within these proposed land-use strategies and reveals that discussions about future management of forest and agricultural lands take place largely exclusive of one another. Based on these results, a land-use concept is proposed in which sustainable agricultural intensification is paired with land-use diversification as a risk reduction strategy and complemented by productive restoration and compensation payments for forest conservation. Improving afforestation and agroforestry practices on degraded lands and investigating effects of diversification on the landscape scale are identified as important objectives for future interdisciplinary research. Considering forests as part of a comprehensive land-use portfolio will be vital in order to help strengthen links and ease conflicts between forest and agricultural land uses.
-
Keywords: |
sustainable land use |
indirect land use change (ILUC) |
natural forest management |
Corti, N. (2014): Forest Burned Area Mapping in Ecuador using Mono-Temporal RapidEye Inmagery and Object Based Image Analysis - Master Thesis Fachgebiet für Waldinventur und nachhaltige Nutzung, Technische Universität München, master thesis
Utiger, C. (2015): Temporal variation of the element concentrations and fluxes in rainfall and throughfall of a tropical montane rain forest in southern Ecuador University of Berne, master thesis
-
log in to download
-
link
-
view metadata
-
Abstract:
Abstract:
Chemical element concentrations and fluxes in the hydrological cycle of a mountain rain forest in southern Ecuador are influenced by annual seasonality, long term trends, inter-annual ENSO cycles and other environmental factors. Some knowledge about this processes was collected in previous studies. But little is known about how much of the variation in the data can be explained by those processes. Goal of this thesis is therefore to build linear models that explain the variation in element concentrations and fluxes in the incident precipitation and in the troughfall of an small forested catchment in southern Ecuador. The linear models contain seasonal terms, trend terms, ENSO temerature anomalie terms and environmental variable terms. For each analysed element four linear model were build to explain variation in concentrations and
fluxes in incident precipitation and troughfall. The models contained all terms at the beginning and were then optimized to a model with only the significant terms for each element in each flux and concentration.
By analysing a time series from 1998 to 2010 with monthly means of element concentrations of weekly measurements of troughfall and incident precipitation, and their resulting fluxes, the following hypothesis are tested. Namely seasonal terms are significantly explaining the variation in the concentrations and fluxes, longterm trends are explaining the variation, ENSO related temperature anomalies are explaining the variation and other environmental factors are explaining the variation. The findings showed that in 45 % of the models seasonality is significantly contributing to the explaining of the variation. A significant trend terms is part of 30% of the models and a significant ENSO term in 18%. The range of percentage of significant environmental variables starts with 16% for wind direction and 18% for flower or fruiting phenology. goes to 25 % and 31 % for fire activity and heavy rain activity respectively and finally goes to 57% for conductivity. To mention is that in this case conductivity is present in 90% of the conductivity
models. The resulting R squares showed that the best models are the troughfall models. The best model
here explains almost 80% of the variation, the median is around 50% of explained variation and the worst model explains 27 % of the variation. In the incident precipitation concentration and in the troughfall and incident precipitation fluxes the best models are between 30 and 40 % of explained variation, the median is about 20% for incident precipitation and between 10 and 15 % for the fluxes and the lowest values are about 5 %. The model quality test shows that the not crucial criteria of normal distribution ot the model residuals is violated in some models. The crucial temporal independence criteria is most likely violated in few models and in one model it is clearly violated. All in all the thesis could show that seasonality, trend, ENSO related temperature anomalies and the environmental variables fire activity, conductivity, wind
direction, heavy rain, and flower and fruiting phenology are in various combinations contributing significantly to the explaining of the variation in concentration and fluxes of incident precipitation
and troughfall. The models are strong in explaining the variation in cases like potassium troughfall concentration, where rainfall seasonality leads to big concentration variation, while in other cases, like magnesium incident precipitation concentrations, where little variation occurs and factors that are not included as model terms lead to clear patterns in the concentrations, the model can explain almost no variation.
-
Keywords: |
seasonality |
temporal trends |
ENSO |
rainfall |
througfall |
element concentrations |
element fluxes |
environmental drivers |
linear models |
Rehmus, A. (2015): Aluminum toxicity in a tropical montane forest ecosystem in southern Ecuador University of Berne, phd thesis
-
log in to download
-
link
-
view metadata
-
Abstract:
Abstract:
Aluminum phytotoxicity frequently occurs in acid soils (pH < 5.5) and was therefore discussed to affect ecosystem functioning of tropical montane forests. The susceptibility to Al toxicity depends on the sensitivity of the plant species and the Al speciation in soil solution, which can vary highly depending e.g., on pH, ionic strength, and dissolved organic matter. An acidification of the ecosystem and periodic base metal deposition from Saharan dust may control plant available Al concentrations in the soil solutions
of tropical montane rainforests in south Ecuador. The overall objective of my study was to assess a potential Al phytotoxicity in the tropical montane forests in south Ecuador. For this purpose, I exposed three native Al non-accumulating tree species (Cedrela odorata L., Heliocarpus americanus L., and Tabebuia chrysantha (Jacq.) G. Nicholson) to increased Al concentrations (0 – 2400 ?M Al) in a hydroponic experiment, I established dose-response curves to estimate the sensitivity of the tree species to increased Al concentrations, and I investigated the mechanisms behind the observed effects induced by elevated Al concentrations. Furthermore, the response of Al concentrations and the speciation in soil solution to Ca amendment in the study area were determined. In a final step, I assessed all major Al fluxes, drivers of Al concentrations in ecosystem solutions, and indicators of Al toxicity in the tropical montane rainforest in Ecuador in order to test for indications of Al toxicity. In the hydroponic experiment, a 10 % reduction in aboveground biomass production occurred at 126 to 376 ?M Al (EC10 values), probably attributable to decreased Mg concentrations in leaves and reduced potosynthesis. At 300 ?M Al, increased root biomass production of T. chrysantha was observed. Phosphorus concentrations in roots of C. odorata and T. chrysantha were significantly highest in the treatment with 300 ?M Al and correlated significantly with root biomass, being a likely reason for stimulated root biomass production. The degree of organic complexation of Al in the organic layer leachate, which is central to plant nutrition because of the high root density, and soil solution from the study area was very high (mean > 99 %). The resulting low free Al concentrations are not likely to affect plant growth, although the concentrations of potentially toxic
Al3+ increased with soil depth due to higher total Al and lower dissolved organic matter concentrations in soil solutions. The Ca additions caused an increase of Al in the organic layer leachate, probably because Al3+ was exchanged against the added Ca2+ ions while pH remained constant. The free ion molar ratios of Ca2+:Al3+ (mean ratio ca. 400) were far above the threshold (smaller than 1) for Al toxicity, because of a much higher degree of organo-complexation of Al than Ca. High Al fluxes in litterfall (8.8 – 14.2 kg ha?1 yr?1) indicate a high Al circulation through the ecosystem. The Al concentrations in the organic layer leachate were driven by the acidification of the ecosystem and increased significantly between 1999 and 2008. However, the Ca:Al molar ratios in organic layer leachate and all aboveground ecosystem solutions were above the threshold for Al toxicity. Except for two Al accumulating and one non-accumulating tree species, the Ca:Al molar ratios in tree leaves from the study area were above the Al toxicity threshold of 12.5. I conclude that toxic effects in the hydroponic experiment occurred at Al concentrations far above those in native organic layer leachate, shoot biomass production was likely inhibited by reduced Mg uptake, impairing photosynthesis, and the stimulation of root growth at low Al concentrations can be possibly attributed to improved P uptake. Dissolved organic matter in soil solutions detoxifies Al in acidic tropical forest soils and a wide distribution of Al accumulating tree species and high Al fluxes in the ecosystem do not necessarily imply a general Al phytotoxicity.
-
Keywords: |
tropical tree seedlings |
Al toxicity |
Al cycling |
Hydroponic growth experiment |
plant nutrition |
hormesis |
Al speciation in solution |
Ca:Al ratios |
Mg:Al ratios |
base saturation |
Rehmus, A.; Bigalke, M.; Valarezo, C.; Mora Castillo, J.R. & Wilcke, W. (2015): Aluminium toxicity to tropical montane forest tree seedlings in southern Ecuador: Response of the nutrient status to elevated Al concentrations. Plant and Soil 388, 87-97.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1007/s11104-014-2276-5
-
Abstract:
Abstract:
Aims We determined the reasons why in nutrient solution increasing Al concentrations>300 ?M inhibited
shoot biomass production of Cedrela odorata L., Heliocarpus americanus L., and Tabebuia chrysantha
(Jacq.) G. Nicholson while 300 ?M Al stimulated root biomass production of Tabebuia chrysantha.
Methods Nutrient concentrations in plant tissue after a hydroponic growth experiment were determined.
Results Increasing Al concentrations significantly decreased Mg concentrations in leaves. Phosphorus
concentrations in roots of C. odorata and T. chrysantha were significantly highest in the treatment with 300 ?M Al and correlated significantly with root biomass.
Conclusions Shoot biomass production was likely inhibited by reduced Mg uptake, impairing photosynthesis.
The stimulation of root growth at low Al concentrations can be possibly attributed to improved P uptake.
-
Keywords: |
phosphorus |
aluminum toxicity |
tropical forest tree seedling |
nutrient deficiency |
growth stimulation |
Werner, F.A.; Köster, N.; Kessler, M. & Gradstein, S.R. (2011): Is the resilience of epiphyte assemblages to human disturbance a function of local climate?. Ecotropica 17, 15-20.
Kotowska, M. & Werner, F.A. (2013): Environmental controls over methane emissions from bromeliad phytotelmata: The role of phosphorus and nitrogen availability, temperature, and water content. GLOBAL BIOGEOCHEMICAL CYCLES 27, 1-8.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1002/2013GB004612
-
Abstract:
Abstract:
Tank bromeliads are common epiphytic plants throughout neotropical forests that store
signi?cant amounts of water in phytotelmata (tanks) formed by highly modi?ed leafs.
Methanogenic archaea in these tanks have recently been identi?ed as a signi?cant source of
atmospheric methane. We address the effects of environmental drivers (temperature, tank
water content, sodium phosphate [P], and urea [N] addition) on methane production in
anaerobically incubated bromeliad slurry and emissions from intact bromeliad tanks in
montane Ecuador. N addition ? 1 mg g 1 had a signi?cantly positive effect on headspace
methane concentrations in incubation jars while P addition did not affect methane
production at any dosage (? 1 mg g 1 ). Tank bromeliads (Tillandsia complanata) cultivated
in situ showed signi?cantly increased ef?uxes of methane in response to the addition of
26 mg N addition per tank but not to lower dosage of N or any dosage of P (? 5.2 mg plant 1 ).
There was no signi?cant interaction between N and P addition. The brevity of the
stimulatory effect of N addition on plant methane ef?uxes (1–2 days) points at N
competition by other microorganisms or bromeliads. Methane ef?ux from plants closely
followed within-day temperature ?uctuations over 24 h cycles, yet the dependency of
temperature was not exponential as typical for terrestrial wetlands but instead linear. In
simulated drought, methane emission from bromeliad tanks was maintained with minimum
amounts of water and regained after a short lag phase of approximately 24 h. Our results
suggest that methanogens in bromeliads are primarily limited by N and that direct effects of
global change (increasing temperature and seasonality, remote fertilization) on bromeliad
methane emissions are of moderate scale.
-
Keywords: |
nutrients |
gas emission |
NUMEX |
N-cycle |
nitrogen |
Gas exchange |
phosphorus |
nutrient manipulation |
nutrient limitation |
phosphorus availability |
nutrient cycle |
methane |
Haukamp, H. & University of Marburg (2014): Phylogenetic and functional diversity of tropical tree communities along an elevation gradient University of Marburg, master thesis
-
link
-
view metadata
-
Abstract:
Abstract:
Projected climate warming will potentially cause profound modifications of ecosystems worldwide, including large redistribution of biodiversity. Among the ecosystems that react most sensitive to climatic changes are tropical mountain rain forests. An essential step to conserve these ecosystems is to study the response of their biodiversity to changing climate conditions. For this purpose elevational gradients are particular suitable. Furthermore, it is important to consider a topographical gradient because of the rugged mountainous study area. Species richness, the commonly used measure for biodiversity, only describes parts of biodiversity. Therefore, it is crucial to additionally study phylogenetic and functional diversity to detect impacts of climate change on ecosystem functions. Hence, the aim of the study was to investigate the influence of an elevational and a topographical gradient on species richness, phylogenetic diversity (PD) and functional composition of two traits, specific leaf area (SLA) and wood specific gravity (WSG), taking tree communities as example. Additionally, I measured the phylogenetic signal of the traits to expose if they are conserved or convergent. By the combination of PD and trait based methods community assembly patterns were detected and furthermore, it was tested if PD mirrors the functional diversity. The results showed no change in rarefied species richness with elevation. In contrast, PD increased from low to mid elevation and decreased from mid to high elevation. The topographical gradient also had an influence on PD. The functional composition of SLA and WSG changed with elevation and partly with topographic position. While SLA values decreased from low to high elevation and were lower on the upper slopes at mid and high elevation, WSG values at high elevation were overall high with a lower range but did not change with topographic position. Both traits appeared to be convergent. Considering the detected trait convergence, it is likely that competitive interactions shape the community at low elevation whereas at high elevation environmental filtering probably is the main assembly process. Furthermore, filtering effects on the upper slope at mid elevation could be exposed. The functional composition of SLA and WSG indicated biotic filters, like competition for light, at low elevation and abiotic stress filters at high elevation. Moreover, a filtering effect of the topographical gradient on SLA on the upper slope at mid and high elevation was detected. Overall, the PD uncovered more facets of the biodiversity than species richness. However, the addition of trait based methods is important to confirm assembly patterns detected by PD and to detect further underlying processes.
-
Keywords: |
tree |
diversity |
elevation |
phylogenetic |
functional |
Tiede, Y. (2014): Elevation and soil parameters shape the taxonomic and phylogenetic diversity of tropical trees in an Ecuadorian mountain rainforest University of Marburg, master thesis
-
link
-
view metadata
-
Abstract:
Abstract:
Natural ecosystems across the globe are already modified in their structure and composition. This often leads to a decline of biodiversity which can in turn affect important ecological functions. Species richness as a measure of biodiversity ignores almost 89% of the overall diversity and many traits of species show a phylogenetic signal. Therefore, phylodiversity is often a better indicator of functional processes than species richness. To better understand changes in ecosystem functionality it is thus essential to study and compare taxonomic and phylogenetic diversity patterns across environmental gradients such as elevation. In this study I therefore analyse the effects of elevation and soil parameters on the taxonomic and phylogenetic diversity of tree communities in an Andean mountain rainforest in southern Ecuador.
427 tree species were recorded on 54 plots at three elevation levels at 1000, 2000 and 3000 m, with phyloalpha diversities ranging between -1.91 and 2.20. There was no distinct pattern of over- or underdispersed phyloalpha diversities along the gradient. Elevation affected both the alpha taxonomic and phylogenetic tree species diversity: While taxonomic diversity declined along the elevation gradient, phyloalpha diversity showed a humped relationship with highest phylodiversity values at mid-elevations. I assume environmental filtering to reduce the taxonomic diversity at high elevation. Simultaneously, I suppose the occurrence of facilitator species to enable a nevertheless phylogenetic diverse tree community to persist at high elevations. At low elevations my findings indicate neutral or stochastic processes to shape the phyloalpha dispersion. Elevation had the strongest direct effect on the phyloalpha diversities. Moreover, it influenced soil parameters which explained an additional amount of the phyloalpha diversities.
The pattern of phylobeta diversity supported the idea of facilitator species at high elevations and revealed two phylogenetic distantly related tree communities to exist at low and high elevation levels. The ranges of both species sets overlap at mid elevations where phylodiversities are most diverse, corresponding to a mid-domain effect at the phylogenetic scale. Drawing conclusions from phylodiversity to functional traits suggests an ecosystem with a high functional trait space along the gradient with a peak at mid-elevations.
Altogether, the analysis of phylodiversity patterns revealed a much more complex picture of the diversity distribution than taxonomic diversity. Furthermore, phylodiversity permitted to find the evolutionary biotic and abiotic processes which shaped the diversity structure.
-
Keywords: |
soil characteristics |
tree |
diversity |
elevation |
phylogenetic |
Astudillo Webster, P.X.; Universidad del Azuay; Samaniego, G.M.; Machado, P.J.; Aguilar, J.M.; Tinoco, B.A.; Graham, C.H.; Stony Brook University; Latta, S.C.; National Aviary (USA) & Farwig, N. (2014): The impact of roads on the avifauna of páramo grasslands in Cajas National Park, Ecuador. Studies on Neotropical Fauna and Environment 49(3), 204-212.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1080/01650521.2014.960778
-
Abstract:
Abstract:
National parks are an important tool for conserving biodiversity, particularly in areas of high biodiversity and endemism such as the tropical Andes. However, national parks often face a variety of stressors related to recreation, road construction and illegal extraction of natural resources. Unfortunately, the influence of these stressors for biodiversity is rarely well documented. Cajas National Park in Ecuador is no exception. Despite being traversed by the Cuenca-Molleturo-Naranjal road, effects of the road construction on biodiversity have not been determined. We therefore assessed the influence of road proximity on bird species richness and abundance as well as composition of bird habitat groups in Cajas National Park using transect walks at 25 m and 250 m distance to the road (overall 18 transects, each 1 km length). In total, we recorded 1110 individuals of 28 páramo bird species. Overall species richness did not differ between transects near and far from the road. Nevertheless, the average abundance of shrubby páramo species was significantly higher far from the road than near the road (Far = 36, Near = 25). Moreover, we found a tendency towards differences in the composition of bird habitat groups between transects near and far from the road. One aspect potentially driving the observed patterns was the increasing proportion of planted non-native woody tree species within páramo grassland near the road, which may have caused reduced abundances of shrubby páramo bird species there. While roads represented a clear impact on the composition of bird species in the páramo, the major effect seems to be driven by the introduction of non- native plant species along the roadside. In order to reduce the impact of roads to a minimum, we suggest that park managers should control the introduction of such plant species.
-
Keywords: |
Paramo |
species richness |
abundance |
bird community |
stressors |
Cajas National Park |
road impact |
Bettac, H.L. (2014): Leaf phenology of deciduous and abundance of evergreen tree species in a tropical dry forest of South Ecuador Georg-August-Universität Göttingen, master thesis
Wittich, B.; Homeier, J. & Leuschner, C. (2014): Ammonium, nitrate and glycine uptake of six Ecuadorian tropical montane forest tree species: an in situ pot experiment with saplings. Journal of Tropical Ecology xx, xx.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1017/S0266467414000650
-
Abstract:
Abstract:
Not much is known about the nitrogen (N) uptake capacity and N-form preference of tropical trees. In a
replicated labelling experiment with 15N-ammonium, 15N-nitrate and dual-labelled glycine applied to saplings of six
tree species from southern Ecuadorianmontane forests, we tested the hypotheses that (1) the saplings of tropical trees
are capable of using organicNeven though they are forming arbuscularmycorrhizas, and (2) with increasing altitude,
tree saplings increasingly prefer ammonium and glycine over nitrate due to reduced nitrification and growing humus
accumulation. Three- to 5-y-old saplings of two species each from 1000, 2000 and 3000 m asl were grown in pots
inside the forest at their origin and labelled with non-fertilizing amounts of the three N forms; 15N enrichment was
detected 5 days after labelling in fine roots, coarse roots, shoots and leaves. The six species differed with respect to
their N-form preference, but neither the abundance of ammonium and nitrate in the soil nor altitude (1000–3000
m asl) seemed to influence the preference. Two species (those with highest growth rate) preferred NH4+ over NO3?,
while the other four species took up NO3? and NH4+ at similar rates when both N forms were equally available. After
13C-glycine addition, 13C was significantly accumulated in the biomass of three species (all species with exclusively
AM symbionts) but a convincing proof of the uptake of intact glycine molecules by these tropical montane forest trees
was not obtained.
-
Keywords: |
nitrogen |
nitrate |
ammonium |
altitudinal gradient |
15N tracer study |
Exbrayat, J.F.; Buytaert, W.; Timbe, E.; Windhorst, D. & Breuer, L. (2014): Addressing sources of uncertainty in runoff projections for a data scarce catchment in the Ecuadorian Andes. Climatic Change --(--), 1-15.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1007/s10584-014-1160-x
-
Abstract:
Abstract:
Future climate projections from general circulation models (GCMs) predict an
acceleration of the global hydrological cycle throughout the 21st century in response to human-induced rise in temperatures. However, projections of GCMs are too coarse in resolution to be used in local studies of climate change impacts. To cope with this problem, downscaling methods have been developed that transform climate projections into high resolution datasets to drive impact models such as rainfall-runoff models. Generally, the range of changes simulated by different GCMs is considered to be the major source of variability in the results of such studies. However, the cascade of uncertainty in runoff projections is further elongated by differences between impact models, especially where robust calibration is hampered by the scarcity of data.
Here, we address the relative importance of these different sources of uncertainty in a poorly monitored headwater catchment of the Ecuadorian Andes. Therefore, we force 7 hydrological models with downscaled outputs of 8 GCMs driven by the A1B and A2 emission scenarios over the 21st century. Results indicate a likely increase in annual runoff by 2100 with a large variability between the different combinations of a climate model with a hydrological
-
Keywords: |
climate change |
Uncertainty analysis |
hydrological catchment model |
Windhorst, D.; Kraft, P.; Timbe, E.; Frede, H. & Breuer, L. (2014): Stable water isotope tracing through hydrological models for disentangling runoff generation processes at the hillslope scale. Hydrol. Earth Syst. Sci. 18(10), 4113-4127.
-
log in to download
-
link
-
view metadata
-
DOI: 10.5194/hess-18-4113-2014
-
Abstract:
Abstract:
Hillslopes are the dominant landscape components
where incoming precipitation becomes groundwater, streamflow
or atmospheric water vapor. However, directly observing
flux partitioning in the soil is almost impossible. Hydrological
hillslope models are therefore being used to investigate
the processes involved. Here we report on a modeling
experiment using the Catchment Modeling Framework
(CMF) where measured stable water isotopes in vertical
soil profiles along a tropical mountainous grassland hillslope
transect are traced through the model to resolve potential
mixing processes. CMF simulates advective transport of
stable water isotopes 18O and 2H based on the Richards equation
within a fully distributed 2-D representation of the hillslope.
The model successfully replicates the observed temporal
pattern of soil water isotope profiles (R2 0.84 and Nash–
Sutcliffe efficiency (NSE) 0.42). Predicted flows are in good
agreement with previous studies. We highlight the importance
of groundwater recharge and shallow lateral subsurface
flow, accounting for 50 and 16% of the total flow leaving the
system, respectively. Surface runoff is negligible despite the
steep slopes in the Ecuadorian study region.
-
Keywords: |
isotopes |
isotope tracers |
hydrological catchment model |
Knoke, T.; Bendix, J.; Pohle, P.; Hamer, U.; Hildebrandt, P.; Roos, K.; Gerique, A.; Lopez Sandoval, M.F.; Breuer, L.; Tischer, A.; Silva, B.; Calvas, B.; Aguirre, N.; Castro, L.M.; Windhorst, D.; Weber, M.; Stimm, B.; Günter, S.; Palomeque, X.; Mora, J.; Mosandl, R. & Beck, E. (2014): Afforestation or intense pasturing improve the ecological and economic value of abandoned tropical farmlands. Nature Communications 5:5612, 1-50.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1038/ncomms6612
-
Abstract:
Abstract:
Increasing demands for livelihood resources in tropical rural areas have led to progressive
clearing of biodiverse natural forests. Restoration of abandoned farmlands could counter
this process. However, as aims and modes of restoration differ in their ecological and
socio-economic value, the assessment of achievable ecosystem functions and bene?ts
requires holistic investigation. Here we combine the results from multidisciplinary research
for a unique assessment based on a normalization of 23 ecological, economic and social
indicators for four restoration options in the tropical Andes of Ecuador. A comparison of the
outcomes among afforestation with native alder or exotic pine, pasture restoration with either
low-input or intense management and the abandoned status quo shows that both variants of
afforestation and intense pasture use improve the ecological value, but low-input pasture
does not. Economic indicators favour either afforestation or intense pasturing. Both Mestizo
and indigenous Saraguro settlers are more inclined to opt for afforestation.
-
Keywords: |
sustainable land-use |
Bahr, E.; Chamba Zaragocin, D.; Fierro Jaramillo, N.; Witt, A. & Makeschin, F. (2014): Modeling of soil nutrient balances, flows and stocks revealed effects of management on soil fertility in south Ecuadorian smallholder farming systems. Nutrient Cycling in Agroecosystems -, -.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1007/s10705-014-9662-5
-
Abstract:
Abstract:
Linking nutrient balances and flows to soil
nutrient stocks creates a valuable indicator for sustainability
assessment in agricultural land-use systems.
Therefore, we investigated the impact of management
on soil fertility at farm/field scale using the Nutmon
approach. A detailed methodology for the adaptation
of the difficult-to-quantify flows to the local conditions
is described. Research was carried out in the three
farming systems of Yantzaza (low-external-input), El
Tambo (irrigated cash crops) and San Lucas (integrated
nutrient management) in southern Ecuador. For
each land-use within a farm (annual and perennial
crops, pasture, forest), soil nutrient balances and flows
were modeled with Nutmon and soil nutrient stocks
were calculated for NPK. Soil nutrient balances were
evaluated using potential socio-economic and soil
fertility explanatory variables. Balances for the different
land-uses in the three research areas varied between
-151 to 66 kg ha-1 a-1 for N, -4 to 33 kg ha-1 a-1 for P and -346 to 39 kg ha-1 a-1 for K and were mainly negative. Up to 70 % of the balances’ variability was explained by soil fertility variables and financial flows. Highest external inputs existed in
land-uses with a strong market orientation. Land-uses
benefiting from a surplus of within-farm flows had the
highest soil nutrient stocks. The focus on N fertilization
induced highly negative PKbalances in annual crops of
El Tambo. In contrast, the application of organic
fertilizers and nutrient recycling in San Lucas resulted
in positive NP balances particularly for perennial
crops. NP balances in annual crops of Yantzaza were
most negative due to nonexistent fertilization, leaching
and burning of crop residues. A non-sustainable landuse
of annual crops in Yantzaza was illustrated by total
N stock decreases of 4.9 % a-1 and decreased soil
organic carbon stocks to 85 % of adjacent forest sites.
Results indicated a potential risk regarding sustainable
management of soils in the research area and provide a
basis for policy and decision makers to develop
appropriate management strategies.
-
Keywords: |
soil nutrient depletion |
Nutmon |
agricultural soil |
sustainable land-use |
within-farm flows |
Mosandl, D. (2014): Lichtmikroskopische und molekulare Untersuchungen der Mykorrhizierung von Páramo-Pflanzen in Süd-Ecuador Universität Tübingen, bachelor thesis
-
log in to download
-
link
-
view metadata
-
Abstract:
Abstract:
In times of climate change and devastation, the conservation of biodiversity is an important issue. The formation of a mycorrhiza plays a very important role. The arbuscular mycorrhiza is a mutualistic symbiosis between fungi and plant roots. The arbuscular mycorrhizal fungi represent a monophyletic group, the Glomeromycota, which probably have a common ancestor with the Asco-and Basidiomycota. The arbuscular mycorrhiza is characterized by an enormous spreading. It is found in all climates. The vast majority of tropical plants form an arbuscular mycorrhiza, including plants in the Páramo, a type of vegetation in the humid tropical high Andes of South America above the treeline.
In this study, root material from the Páramo-vegetation in Cajanuma in South Ecuador was examined. The analysis can be divided into two parts, the morphological and genetic analyses.
Concerning the morphology the root samples were analysed under the light microscope. In 16 of 20 samples colonization with arbuscular mycorrhizal fungi was detected. Exactly these 16 samples also showed fungi belonging to the group of dark sepatate endophytes (DSE) which are likely representatives of the Ascomycota.
In the context of genetic analyses arbuscular mycorrhizal fungi have been analysed with molecular methods sequencing part of the 18S rDNA. For the identification of fungi, which do not belong to the Glomeromycota, a part of the ITS-region of the DNA has been studied and sequenced.
The sequences of arbuscular mycorrhizal fungi belong to families of Glomeraceae and Acaulosporaceae. In comparison with other investigations it can be assumed that the Páramo in Cajanuma has its own AMF community.
The sequences of the Ascomycota all belong to the order of the Helotiales. By comparing the results to other investigations it could be demonstrated, that the dark septate endophytes survive under several climatic conditions. Furthermore they probably play an important role in the supply of nutrients.
In this work, the dark septate endophytes show a greater range of species than the arbuscular mycorrhizal fungi. That possibly indicates a higher diversity in the Ascomycota than in the Glomeroycota in the Páramo-vegetation in Cajanuma. In order to confirm this hypothesis, a far greater data base is required. This data base will be the key to maintaining biodiversity. It ensures a better understanding of fungi and their interactions. Through this understanding, new approaches to protect biodiversity can be created.
-
Keywords: |
Cajanuma |
arbuscular mycorrhiza |
Paramo |
mycobionts |
ascomycota |
Werner, F.A. & Homeier, J. (2014): Is tropical montane forest heterogeneity promoted by a resource-driven feedback cycle? Evidence from nutrient relations, herbivory and litter decomposition along a topographical gradient. Functional Ecology x(x), x.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1111/1365-2435.12351
-
Abstract:
Abstract:
1. Ridges of tropical mountains often differ strikingly from neighbouring ravines in terms of
forest structure, productivity and species composition. This heterogeneity is poorly understood
despite its critical role in biodiversity maintenance, carbon and nutrient budgets.
2. We examined measures of tree biomass and productivity, foliage and litter quality (nutrient
concentrations, specific leaf mass, phenolics), herbivory and leaf litter decomposition in each
six plots laid out in upper and lower slope position in a tropical montane moist forest in southeastern
Ecuador.
3. Productivity, quality of foliage and litter as well as herbivory were significantly lower in
upper slope position, and closely correlated with soil nutrient concentrations and accumulated
humus. The decomposition of upper slope leaf litter (decomposition rate k) was substantially
lower than in litter from lower slope forest, whereas the site of decomposition (slope position)
only had a marginal effect on the decomposition rate.
4. Our results suggest that the differences in stand structure, productivity, foliar quality, herbivory
and decomposition between slope positions are ultimately due to stronger nutrient limitations
in upper slope forest. We propose a general conceptual model that explains origin and
maintenance of contrasting forest types along topographical gradients through down-slope
fluxes of nutrients and water, and a nutrient-driven positive feedback cycle.
-
Keywords: |
topographic heterogenity |
DFG PAK 823-825 (2014): MRp|SE Newsletter, Issue 2. Laboratory for Climatology and Remote Sensing (LCRS), University of Marburg, Marburg, Germany.
Makowski, S.; Rollenbeck, R.; Trachte, K. & Bendix, J. (2014): Natural or anthropogenic? On the origin of atmospheric sulfate deposition in the Andes of southeastern Ecuador. Atmos. Chem. Phys 14, 11297–11312.
-
log in to download
-
link
-
view metadata
-
DOI: 10.5194/acp-14-11297-2014
-
Abstract:
Abstract:
Atmospheric sulfur deposition above certain limits
can represent a threat to tropical forests, causing nutrient
imbalances and mobilizing toxic elements that impact biodiversity
and forest productivity. Atmospheric sources of sulfur
deposited by precipitation have been roughly identified in
only a few lowland tropical forests. Even scarcer are studies
of this type in tropical mountain forests, many of them megadiversity
hotspots and especially vulnerable to acidic deposition.
In these places, the topographic complexity and related
streamflow conditions affect the origin, type, and intensity of
deposition. Furthermore, in regions with a variety of natural
and anthropogenic sulfur sources, like active volcanoes and
biomass burning, no source emission data has been used for
determining the contribution of each source to the deposition.
The main goal of the current study is to evaluate sulfate
(SO?
4 ) deposition by rain and occult precipitation at two topographic
locations in a tropical mountain forest of southern
Ecuador, and to trace back the deposition to possible emission
sources applying back-trajectory modeling. To link upwind
natural (volcanic) and anthropogenic (urban/industrial
and biomass-burning) sulfur emissions and observed sulfate
deposition, we employed state-of-the-art inventory and satellite
data, including volcanic passive degassing as well. We
conclude that biomass-burning sources generally dominate
sulfate deposition at the evaluated sites. Minor sulfate transport
occurs during the shifting of the predominant winds
to the north and west. Occult precipitation sulfate deposition
and likely rain sulfate deposition are mainly linked to
biomass-burning emissions from the Amazon lowlands. Volcanic
and anthropogenic emissions from the north and west
contribute to occult precipitation sulfate deposition at the
mountain crest Cerro del Consuelo meteorological Station and to rain-deposited sulfate at the upriver mountain pass El
Tiro meteorological station.
-
Keywords: |
Nutrient deposition |
Sagra, J. (2013): Tree growth responses to N and P fertilization in Ecuadorian montane forest Universidad Internacional Menéndez Pelayo, master thesis
Jiménez Fadrique, B. (2012): Effects of altitude and topography on liana biomass in southern Ecuadorian montane forests Universidad Internacional Menéndez Pelayo, master thesis
Link, R. (2014): Spatial distribution of angiosperm species in a tropical Andean mountain ecosystem in southern Ecuador University of Goettingen, master thesis
Iniguez, C.; Leiva Calderón, A.; Breuer, L.; Frede, H. & Hampel, H. (2014): Deforestation and benthic indicators: How much vegetation cover is needed to sustain healthy Andean streams? . PLoS ONE 9(8), e105869.
Silva, B.; Roos, K.; Fries, A.; Rollenbeck, R.; Beck, E. & Bendix, J. (2014): Mapping Two Competing Grassland Species from a Low-Altitude Helium Balloon. IEEE Journal of selected topics in applied earth observations and remote sensing 7(7), 3038 - 3049.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1109/JSTARS.2014.2321896
-
Abstract:
Abstract:
This paper describes a method of low-altitude remote
sensing in combination with in situ measurements (leaf area, spectroscopy, and position) to monitor the postfire canopy recovery of two competing grassland species. The method was developed in the Andes of Ecuador, where a tethered balloon with a digital camera was deployed to record a time series of very high spatial resolution
imagery ( nominal resolution = 2cm ) of an experimental plot covered by two competing species: 1) the pasture grass, Setaria sphacelata; and 2) the invasive southern bracken, Pteridium arachnoideum. Image processing techniques were combined to solve geometric issues and construct high-quality mosaics for image classification. The semiautomatic and object-oriented classification method was based on geometrical and textural attributes of image segments and showed promising results for detecting the invasive bracken fern in Setaria pastures (performance by area under the curve, AUC = 0.88). Valuable insights are given into vegetation monitoring applications using unmanned aerial vehicles, which produces a time series of species-specific maps, including foliage projective cover (FPC) and leaf area index (LAI). This new method constitutes an important and accessible tool for ecological investigations of competing species in pastures and validation of remote sensing information on mountain environments.
-
Keywords: |
bracken |
pasture |
land cover |
LAI |
remote sensing |
abandoned pasture |
burning |
Bracken fern |
Jantz, N.; Homeier, J. & Behling, H. (2014): Representativeness of tree diversity in the modern pollen rain of Andean montane forests. Journal of Vegetation Science 25(2), 481-490.
-
log in to download
-
link
-
view metadata
-
DOI: 10.1111/jvs.12105
-
Abstract:
Abstract:
Questions: To assess the relationship between modern pollen rain and Andean
montane forest vegetation for diversity, and provide a basis for interpretations of
palaeoecological data in the northern Andes, we asked: (1) can the reduction of
plant and pollen data to family level preserve information about diversity in both
data sets; (2) how precisely do tree pollen and spore types represent richness patterns
along an altitudinal gradient on tropical mountains; and (3) how similar
are tree pollen and spore family richness in relationship to tree family richness?
Location: Tropicalmontane rain forests, Podocarpus National Park in the Andes
of South Ecuador (3°S, 79°W, 1000–3000 ma.s.l.).
Methods:We analysed tree diversity and species composition in three different
rain forest types: Premontane (PMF), lowermontane (LMF) and uppermontane
(UMF).We investigated modern pollen rain using pollen traps. After testing the
reliability of a taxonomic surrogacy on the plant data, we compared abundance
and representation, as well as diversity of the two data sets at family level. This
was done using rarefaction and Sørensen indices.
Results: The correlation between tree species and families was high (r = 0.81,
P < 0.001). Sample rarefaction on tree pollen and plant family data revealed
highest pollen diversity on sites of the UMF, but highest tree diversity on LMF
and PMF sites. The Sørensen indices indicate down-drift of pollen from higher
altitudes in PMF and LMF and up-drift in UMF. Between 1% and 50% of pollen
taxa of each sample originate fromoutside the plot.
Conclusions: Taxonomic surrogacy at family level is a good tool for comparing
presence–absence patterns of plant and pollen data in tropical regions with high
tree diversity. On a family basis, pollen presence–absence data represent the corresponding
tree vegetation data, but uncertainties increase with decreasing altitude.
The higher diversity in pollen data of the UMF, but slightly lower diversity
in the LMF and PMF, can at least partly be explained by wind patterns, local
abundance of shrubs and herbs and differences in evenness.
-
Keywords: |
MATRIX |