Publications
Found 861 publication(s)
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Werner, F.A.; Ledesma, K.J. & Hidalgo, R. (2006): Mountain viscacha (Lagidium cf. peruanum) in Ecuador - a first record of Chinchillidae for the northern Andes. Mastozoología Neotropical 13, 271-274.
Matt, F. & Werner, F.A. (2007): Mammals. Checklist of the Reserva Biológica San Francisco (Prov. Zamora-Chinchipe, S-Ecuador). Ecotropical Monographs 4, 125-129.
Werner, F.A. & Gradstein, S.R. (2008): Seedling establishment of vascular epiphytes on isolated and enclosed forest trees in an Andean landscape, Ecuador. Biodiversity and Conservation 17(13), 3195-3207.
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DOI: 10.1007/s10531-008-9421-5
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The impact of human disturbance on colonisation dynamics of vascular epiphytes
is poorly known. We studied abundance, diversity and floristic composition of epiphyte
seedling establishing on isolated and adjacent forest trees in a tropical montane landscape. All
vascular epiphytes were removed from plots on the trunk bases of Piptocoma discolor. Newly
established epiphyte seedlingswere recorded after 2 years, and their survival after another year.
Seedling density, total richness at family and genus level, and the number of families and genera
per plot were significantly reduced on isolated trees relative to forest trees. Seedling assemblages
on trunks of forest trees were dominated by hygrophytic understorey ferns, those on
isolated trees by xerotolerant canopy taxa. Colonisation probability on isolated trees was
significantly higher for plots closer to forest but not for plots with greater canopy or bryophyte
cover. Seedling mortality on isolated trees was significantly higher for mesophytic than for
xerotolerant taxa. Our results show that altered recruitment can explain the long-term impoverishment
of post-juvenile epiphyte assemblages on isolated remnant trees.We attribute these
changes to a combination of dispersal constraints and the harshermicroclimate documented by
measurements of temperature and humidity. Although isolated trees in anthropogenic landscapes
are considered key structures for themaintenance of forest biodiversity inmany aspects,
our results show that their value for the conservation of epiphytes can be limited.We suggest
that abiotic seedling requirementswill increasingly constitute a bottleneck for the persistence of
vascular epiphytes in the face of ongoing habitat alteration and atmospheric warming.
Werner, F.A. & Gradstein, S.R. (2009): Diversity of dry forest epiphytes along a gradient of human disturbance in the tropical Andes. Journal of Vegetation Science 20(1), 59-68.
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DOI: 10.3170/2008-8-18466
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Question: Disturbance effects on dry forest epiphytes are poorly known. How are epiphytic assemblages affected by different degrees of human disturbance, and what are the driving forces?
Location: An inter-Andean dry forest landscape at 2300 m elevation in northern Ecuador.
Methods: We sampled epiphytic bryophytes and vascular plants on 100 trees of Acacia macracantha in five habitats: closed-canopy mixed and pure acacia forest (old secondary), forest edge, young semi-closed secondary woodland, and isolated trees in grassland.
Results: Total species richness in forest edge habitats and on isolated trees was significantly lower than in closed forest types. Species density of vascular epiphytes (species per tree) did not differ significantly between habitat types. Species density of bryophytes, in contrast, was significantly lower in edge habitat and on isolated trees than in closed forest. Forest edge showed greater impoverishment than semi-closed woodland and similar floristic affinity to isolated trees and to closed forest types. Assemblages
were significantly nested; habitat types with major disturbance held only subsets of the closed forest assemblages, indicating a gradual reduction in niche availability. Distance to forest had no effect on species density of epiphytes on isolated trees, but species density was closely correlated with crown closure, a measure of canopy integrity.
Main conclusions: Microclimatic changes but not dispersal constraints were key determinants of epiphyte assemblages following disturbance. Epiphytic cryptogams are sensitive indicators of microclimate and human disturbance in montane dry forests. The substantial impoverishment of edge habitat underlines the need for fragmentation studies on epiphytes elsewhere in the Tropics.
Nauss, T.; Göttlicher, D.; Dobbermann, M. & Bendix, J. (2007): Central Data Services in Multidisciplinary Environmental Research Projects. eZAI 2, 1-13.
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Multidisciplinary research projects bear a great potential for the exploration and understanding of complex interrelations e. g. between ecosystem and atmospheric processes. On the other hand, cooperating scientist often face the problem of finding effective yet time inexpensive ways of data and knowledge transfer between the individual working groups in order to maximize synergetic effects and consequently to succeed in research. Based on the experience within different multidisciplinary research projects, the authors introduce two different concepts for central data services and discuss the related advantages and disadvantages using the DFG research unit 402 and 816 as an exemplarily case. In general, it can be established that the required degree of interaction between the working group is a good indicator for choosing between the different central data service concepts.
Bendix, J.; Rollenbeck, R.; Göttlicher, D.; Nauss, T. & Fabian, P. (2008): Seasonality and diurnal pattern of very low clouds in a deeply incised valley of the eastern tropical Andes (South Ecuador) as observed by a cost-effective WebCam system. Meteorological Applications 15, 281-291.
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DOI: 10.1002/met.72
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To date, the annual and diurnal pattern of low clouds touching the ground in tropical mountains is widely unknown. This holds true for the valley of the Rio San Francisco in southern Ecuador, and is mainly due to a lack of routine cloud observations, which is symptomatic for remote areas in tropical high mountains. A method to use a simple and cost-effective WebCam system for a quantitative analysis of cloud frequency as a proxy for the occurrence of low-cloud bases touching the ground is introduced. An interactive classification tool is developed, which is applied to a comprehensive dataset of 32 452 images (during the years 2002?2004) archived at 5 min intervals. The results point
to a rapid increase of cloud frequency at altitudes >2600 m asl both during the day and the year, mainly caused by advective clouds veiling the crests of the Cordillera del Consuelo. Even if the formation of radiation fog directly at the valley bottom is nearly negligible with regard to the whole dataset, scatterometer measurements suggest that valley fog formation on the slopes is a regular process during the night, causing a clear drop in the cloud base around sunrise. The interaction of low-radiative and high-advective clouds is supposed to be the driving factor for a rainfall maximum at the valley bottom around sunrise. Higher values of cloud frequency still exist at the crest level around noon: these originate from well-developed upslope-breeze systems.
Fleischbein, K.; Wilcke, W.; Valarezo, C.; Zech, W. & Knoblich, K. (2006): Water budgets of three small catchments under montane forest in Ecuador: experimental and modelling approach. Hydrological Processes 20, 2491-2507.
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DOI: 10.1002/hyp.6212
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The water budget of forested catchments controls the local water supply and influences the regional climate. To assess anthropogenic impact on the water cycle we constructed a water budget for three ~10 ha catchments under lower montane forest on the east-facing slope of the Andes in south Ecuador at 1900-2150 m elevation. We used field hydrological measurements and modeled surface flows with TOPMODEL, a semi-distributed catchment model. We measured incident precipitation, throughfall, stemflow, and surface flow between May 1998 and April 2002 in hourly to weekly resolution, and determined all variables needed to parameterize TOPMODEL. On average of the four monitored years and three catchments, incident precipitation was 2504±s.d.123 mm, throughfall 1473±197 mm, and stemflow 25±2 mm yr-1. Fog water input was negligible. Mean annual interception loss in the forest was 1006±270 mm, and mean annual surface flow, calculated with TOPMODEL in an hourly resolution was 1039±48 mm. The resulting mean annual evapotranspiration was 1466±161 mm of which 32% (=471±162 mm) was transpiration if evaporation from the soil was neglected. Our study catchments show a high evapotranspiration attributable to the strong solar insolation near the equator, the small impact of fog, the generally low intensity of incident precipitation and additional wind-driven advective energy input.
Knoke, T.; Stimm, B. & Weber, M. (2008): Tropical farmers need productive alternatives. Nature 452, 934.
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DOI: 10.1038/452934b
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SIR ? Your Editorial ?Markets can save forests? proposes integrating deforestation into the international carbon market (Nature 452, 127?128; 2008), but it is unlikely that money alone can solve the problem.
The process of tropical deforestation presents a dilemma: enormous economic value more than US$ 2,000 a year per hectare is lost in favour of small private benefits (often less than US$ 100 a year per hectare). In a true market, an increased, scarcity-signalling price should provide an incentive to boost the supply of the scarce commodity. So far, this has not worked in the case of tropical forests. Real financial flows received for the provision of ecosystem services are vanishingly small, if they exist at all ? only a few beneficiaries have been convinced to pay for environmental services. This illustrates the essentially theoretical character (at least, up till now) of economic values generated by ecosystem services.
Payments for ecosystem services (PES) are supposed to save tropical forests. But even if it were possible to mobilize substantial PES, tropical farmers wouldn?t be prepared to stand by and twiddle their thumbs while receiving these payments to protect the forest. They need a field of activity, so sustainable land-use concepts should address the social environment and needs of people as well. These concepts could be linked and possibly financed by PES.
If the people who use tropical lands are disregarded, we don?t believe that PES will solve the problem of disappearing tropical forests. What is needed is an economic system that keeps people gainfully employed in an activity that is ultimately productive, not destructive.
Zimmermann, A.; Wilcke, W. & Elsenbeer, H. (2007): Spatial and temporal patterns of throughfall quantity and quality in a tropical montane forest in Ecuador.. Journal of Hydrology 343, 80-96.
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DOI: 10.1016/j.jhydrol.2007.06.012
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In forests, complex canopy processes control the change in volume and chemical composition of rain water. We hypothesize that (i) spatial patterns, (ii) the temporal stability of spatial patterns, and (iii) the temporal course of solute concentrations can be used to explore these processes. The study area at 1950 m above sea level in the south Ecuadorian Andes is far away from anthropogenic emission sources and marine influences. It received ca. 2200 mm of rain annually. We collected rain and throughfall on an event and within-event basis for five precipitation periods between August and October 2005 at up to 25 sites and analyzed the samples for pH and concentrations of , , , , , , , , and total N ( ), P ( ), and organic C ( ). Cumulative throughfall amounted to 79% of rainfall. Compared with other tropical forests, rainfall solute concentrations were low and throughfall solute concentrations similar. Volumes and solute concentrations of rainfall were spatially and temporally little variable. The spatial coefficient of variation for throughfall volumes was 53%, for solute concentrations 28292%, and for deposition 33252%. Temporal persistence of spatial patterns was high for throughfall volumes and varied among solutes. Spatial patterns of , and concentrations in throughfall were highly persistent. The spatial patterns of throughfall fluxes were less stable than those of concentrations. During a monitoring time of 72 hours, solute concentrations in throughfall of selected rain events remained at a similar level indicating that the leachable element pool in the canopy was not exhausted. Our results demonstrate that the passage of rain through the canopy of a tropical montane forest in Ecuador results in a spatially heterogeneous throughfall pattern with a considerable stability during three months. There is a large leachable element pool in the canopy, which is not depleted by the typical light rain within 72 hours.
Wilcke, W.; Oelmann, Y.; Schmitt, A.; Valarezo, C.; Zech, W. & Homeier, J. (2008): Soil properties and tree growth along an altitudinal transect in Ecuadorian tropical montane forest. Journal of Plant Nutrition and Soil Science 171, 220-230.
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DOI: 10.1002/jpln.200625210
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In tropical montane forests, soil properties change with altitude and tree growth decreases. In a tropical montane forest in Ecuador, we determined soil and tree properties along an altitudinal transect between 1960 and 2450 m above seal level. In different vegetation units height, basal area, and diameter growth of trees were recorded, and all horizons of three replicate profiles at each of eight sites were sampled. We determined pH and total concentrations of Al, C, Ca, K, Mg, Mn, N, Na, P, S, Zn, polyphenols, and lignin in all soil horizons and in the mineral soil additionally the effective cation-exchange capacity (ECEC). The soils were Cambisols, Planosols, and Histosols. The concentrations of Mg, Mn, N, P, and S in the O horizons and of Al, C, and all nutrients except Ca in the A horizons correlated significantly negatively with altitude. The C/N, C/P, and C/S ratios increased and the lignin concentrations decreased in O and A horizons with increasing altitude. Forest stature, tree basal area, and tree growth decreased with altitude. An ANOVA analysis indicated that macronutrients (e.g., N, P, Ca) and micronutrients (e.g., Mn) in the organic layer and in the soil mineral A horizon were correlated with tree growth. Furthermore, lignin concentrations in the organic layer and the C/N ratio in soil affected tree growth. These effects were consistent, even if the effect of altitude was accounted for in a statistical hierarchical model. This suggests a contribution of nutrient deficiencies to reduced tree growth possibly caused by reduced organic matter turnover at higher altitudes.
Boy, J. & Wilcke, W. (2008): Tropical Andean forest derives calcium and magnesium from Saharan dust.. Global Biogeochemical Cycles 22, GB1027.
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DOI: 10.1029/2007GB002960
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[1] We quantified base metal deposition to Amazonian montane rainforest in Ecuador between May 1998 and April 2003 and assessed the response of the base metal budget of three forested microcatchments (8-13 ha). There was a strong interannual variation in deposition of Ca [4.4-29 kg ha-1 yr-1], Mg [1.6-12], and K [9.8-30]). High deposition changed the Ca and Mg budgets of the catchments from loss to retention, suggesting that the additionally available Ca and Mg was used by the ecosystem. Increased base metal deposition was related to dust outbursts of the Sahara and an Amazonian precipitation pattern with trans-regional dry spells allowing for dust transport to the Andes. The increased base metal deposition coincided with a strong La Niña event in 1999/2000.
Niemann, H. & Behling, H. (2008): Late Quaternary vegetation, climate and fire dynamics inferred from the El Tiro record in the southeastern Ecuadorian Andes. Journal of Quaternary Science 23(3), 203-212.
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DOI: 10.1002/jqs.1134
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In order to study the stability and dynamics of mountain rainforest and paramo ecosystems, including the biodiversity of these ecosystems, the Holocene and late Pleistocene climate and fire variability, and human impact in the southeastern Ecuadorian Andes, we present a high-resolution pollen record from El Tiro Pass (2810m elevation), Podocarpus National Park. Palaeoenvironmental changes, investigated by pollen, spores and charcoal analysis, inferred from a 127cm long core spanning the last ca. 21 000 cal. yr BP, indicate that grass-paramo was the main vegetation type at the El Tiro Pass during the late Pleistocene period. The grass-paramo was rich in Poaceae, Plantago rigida and Plantago australis, reflecting cold and moist climatic conditions. During the early Holocene, from 11200 to 8900 cal. yr BP, subparamo and upper mountain rainforest vegetation expanded slightly, indicating a slow warming of climatic conditions during this period. From 8900 to 3300 cal. yr BP an upper mountain rainforest developed at the study site, indicated by an increase in Hedyosmum, Podocarpaceae, Myrsine and Ilex. This suggests a warmer climate than the present day at this elevation. The modern subparamo vegetation became established since 3300 cal.yr BP at El Tiro Pass. Fires, probably anthropogenic origin, were very rare during the late Pleistocene but became frequent after 8000 cal. yr BP.
Sklenar, P.; Bendix, J. & Balslev, H. (2008): Cloud frequency correlates to plant species composition in the high Andes of Ecuador. Basic and Applied Ecology 9(5), 504-513.
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DOI: 10.1016/j.baae.2007.09.007
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Two data sets representing atmospheric moisture are available for the high Andes of Ecuador, (i) cloud frequency obtained from weather satellites, and (ii) interpolated rainfall estimates obtained from global climate observations. We analyzed their correlation to vascular plant species composition at 18 Ecuadorian superpa´ ramo study sites. Of
particular interest was whether cloud frequency could be used as a proxy for precipitation. Cloud frequency had distinct seasonal and spatial variation among the sites. The spatial gradient of cloudiness was strongest during JuneAugust and weakest around the equinoctials. Interpolated rainfall estimates also showed seasonal and spatial
variation among the sites, but there was no correlation between them and cloudiness. Cloud frequency during JuneAugust was the only significant variable in the canonical correspondence analysis (CCA) of the species composition, whereas rainfall estimates, geology, presence of glaciers, and size and altitudinal range of the superpa´ ramos were not significant. When the spatial components were filtered out from the species composition data by employing partial CCA, cloud frequency during DecemberFebruary became the only significant variable. Our results suggest that cloud frequency data may be a useful tool in mountain ecology research, serving as an indicator of habitat humidity when exact precipitation data are lacking.
Kottke, I.; Beck, A.; Haug, I.; Setaro, S.; Jeske, V.; Suarez, J.P.; Paxmiño, L.; Preussig, M.; Nebel, M. & Oberwinkler, F. (2008): Mycorrhizal state and new and special features of mycorrhizae of trees, ericads, orchids, ferns and liverworts in the tropical mountain rain forest of South Ecuador. In: Beck, Erwin; Bendix, Jörg; Kottke, Ingrid; Makeschin, Franz; Mosandl, Reinhard (eds.): Gradients in a Tropical Mountain Ecosystem of Ecuador (Ecological Studies 198), Springer, Berlin Heidelberg, 137-147.
Beck, E. & Kottke, I. (2008): Facing a hotspot of tropical biodiversity. Basic and Applied Ecology 9, 1-3.
Setaro, S.; Kottke, I. & Oberwinkler, F. (2006): Anatomy and ultrastructure of mycorrhizal associations of neotropical Ericaceae. Mycological Progress 5, 243-254.
Kottke, I.; Haug, I.; Setaro, S.; Suarez, J.P.; Weiß, M.; Preussig, M.; Nebel, M. & Oberwinkler, F. (2008): Guilds of mycorrhizal fungi and their relation to trees, ericads, orchids and liverworts in a neotropical mountain rain forest . Basic and Applied Ecology 9, 13-23.
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DOI: 10.1016/j.baae.2007.03.007
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Mycorrhizas of vascular plants and mycorrhiza-like associations of liverworts and hornworts are integral parts of terrestrial ecosystems, but have rarely been studied in tropical mountain rain forests. The tropical mountain rain forest area of the Reserva Biológica San Francisco in South Ecuador situated on the eastern slope of the Cordillera El Consuelo is exceptionally rich in tree species, ericads and orchids, but also in liverworts. Previous light and electron microscopical studies revealed that tree roots are well colonized by structurally diverse Glomeromycota, and that epiphytic, pleurothallid orchids form mycorrhizas with members of the Tulasnellales and the Sebacinales (Basidiomycota). Sebacinales also occurred in mycorrhizas of hemiepiphytic ericads and Tulasnellas were found in liverworts belonging to the Aneuraceae. On the basis of these findings we hypothesized that symbiotic fungi with a broad host range created shared guilds or even fungal networks between different plant species and plant families. To test this hypothesis, molecular phylogenetic studies of the fungi associated with roots and thalli were carried out using sequences of the nuclear rDNA coding for the small subunit rRNA (nucSSU) of Glomeromycota and the large subunit rRNA (nucLSU) of Basidiomycota. Sequence analyses showed that Sebacinales and Tulasnellas were only shared within but not between ericads and orchids or between liverworts and orchids, respectively. Regarding arbuscular mycorrhiza forming trees, however, 18 out of 33 Glomus sequence types were shared by two to four tree species belonging to distinct families. Nearly all investigated trees shared one sequence type with another tree individual. Host range and potential shared guilds appeared to be restricted to the plant family level for Basidiomycota, but were covering diverse plant families in case of Glomeromycota. Given that the sequence types as defined here correspond to fungal species, our findings indicate potential fungal networks between trees.
Beck, A.; Haug, I.; Oberwinkler, F. & Kottke, I. (2007): Structural characterisation and molecular identification of arbuscular mycorrhiza morphotypes of Alzatea verticillata (Alzateaceae) a prominent tree in the tropical mountain rain forest of South Ecuad. Mycorrhiza 17, 607-625.
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DOI: 10.1007/s00572-007-0139-0
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The vast majority of the highly diverse trees in the tropical mountain rain forest of South Ecuador form arbuscular mycorrhizas and previous molecular investigations revealed a high diversity of fungi. Here we present a first trial to link fungal DNA-sequences with defined morphotypes characterized on the basis of partly new mycelial features obtained from field material of one tree species, Alzatea verticillata. Fine roots were halved lengthwise to study the mycelium anatomy on one half and to obtain fungal nuclear rDNA coding for the small subunit rRNA (nucSSU) of Glomeromycota from the other half. Light microscopy revealed conspicuously large amounts of mycelium attaching to the surface of the rootlets. The mycelium formed fine or large branched appressoria-like plates, vesicles of regular or irregular shape, and very fine, multi-branched hyphal systems ensheathed by septate hyphae. These previously undescribed features of the supraradical mycelia combined with intraradical mycelium structures were used for distinguishing of four main morphogroups and subordinate 14 morphotypes. DNA sequences of Glomus-group A, Acaulospora and Gigaspora were obtained and linked to three morphogroups. Two sequence types within Glomus-group A could be tentatively associated to subordinate morphotypes.
Beck, E.; Bendix, J.; Kottke, I.; Makeschin, F. & Mosandl, R. 2008: Gradients in a tropical mountain ecosystem of Ecuador.: Ecological Studies 198 (Springer, Berlin, Heidelberg).
Zimmermann, R.; Soplin Roque, H.; Börner, A. & Mette, T., Tree Growth History, Stand Structure, and Biomass of Premontane Forest Types at the Cerro Tambo, Alto Mayo, Northern Peru(München, 2003).
Zimmermann, B.; Elsenbeer, H. & De Moraes, J.M. (2006): The influence of land-use changes on soil hydraulic properties: Implications for runoff generation. Forest Ecology and Management 222(1-3), 29-38.
Wurst, S.; Langel, R.; Reineking, A.; Bonkowski, M. & Scheu, S. (2003): Effects of earthworms and organic litter distribution on plant performance and aphid reproduction. Oecologia 137, 90-96.
Wolff, D.; Braun, M. & Liede, S. (2003): Nocturnal Versus Diurnal Pollination Success in Isertia Iaevis (Rubiaceae): A Sphingophilous Plant Visited by Hummingbirds. Plant Biology 5, 71-78.
Wolff, D. (2006): Nectar Sugar Composition and Volumes of 47 Species of Gentianales from a Southern Ecuadorian Montane Forest. Annals of Botany 97, 767-777.
Wilcke, W.; Yasin, S.; Valarezo, C. & Zech, W. (2001): Change in water quality during the passage through a tropical montane rain forest in Ecuador. Biogeochemistry 55, 45-72.
Wilcke, W.; Yasin, S.; Abramowski, U.; Valarezo, C. & Zech, W. (2002): Nutrient storage and turnover in organic layers under tropical montane rain forest in Ecuador. European Journal of Soil Science 53, 15-27.
Wilcke, W.; Valladarez, H.; Stoyan, R.; Yasin, S.; Valarezo, C. & Zech, W. (2003): Soil properties on a chronosequence of landslides in montane rain forest, Ecuador. Catena 53, 79-95.
Wilcke, W.; Hess, T.; Bengel, C.; Homeier, J.; Valarezo, C. & Zech, W. (2005): Coarse woody debris in a montane forest in Ecuador: mass, C and nutrient stock, and turnover. Forest Ecology and Management 205, 139-147.
Werner, F.A.; Homeier, J. & Gradstein, S.R. (2005): Diversity of vascular epiphytes on isolated remnant trees in the montane forest belt of southern Ecuador. Ecotropica 11, 21-40.
Setaro, S.; Weiß, M.; Oberwinkler, F. & Kottke, I. (2006): Sebacinales form ectendomycorrhizas with Cavendishia nobilis, a member of the Andean clade of Ericaceae, in the mountain rain forest of southern Ecuador. New Phytologist 169, 355-365.