Publications
Found 41 publication(s)
- of type article
Schoen, J.; Keuth, R.; Homeier, J.; Limberger, O.; Bendix, J.; Farwig, N. & Brandl, R. (2024): Do leaf traits shape herbivory in tropical montane rainforests? A multispecies approach. Ecosphere 15(10), 1-15.
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DOI: 10.1002/ecs2.70018
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Abstract:
Abstract:
The co-evolutionary arms race between herbivores and plants forces plants to evolve protection strategies that reduce the palatability of the plant modules attacked by the herbivores. These characteristics of traits have consequences for both the survival of plant individuals and the composition of plant communities. Thus, correlating traits of for instance leaves with herbivory is an important step toward understanding the dynamics of plant populations and communities. Traits can either be measured using conventional lab methods or recently developed spectral sensing techniques. We examined whether leaf traits of trees are related to herbivory in a multispecies approach. Furthermore, we explored whether leaf traits characterized by spectral sensing provide similar relations to herbivory as lab-based leaf traits. We established nine 1-ha square plots evenly distributed over three different forest types in Ecuadorian tropical montane rainforests where we estimated herbivory as the leaf area loss (in square centimeters) of 20 (±5) leaves sampled from the canopies of 380 tree individuals belonging to 51 tree species (7 ± 1 individuals/species) using lab- and spectral-sensing-based methods. For each methodological approach, we ran 100 linear mixed-effects models with all respective leaf traits as predictor and herbivory as response variables for data subsets containing one randomly selected tree individual of each species to estimate the range of the regression coefficients for each trait. Automated stepwise backward selections determined the frequency of each trait having an important influence on herbivory. We found no clear relations between leaf traits and herbivory for neither lab- nor spectral-sensing-based traits. A nested variance component analysis demonstrated that the observed variability was mainly due to the variation in trait concentrations between tree individuals of a species. Our results suggest that snapshot data lead to a mismatch between herbivory and the concentrations of traits during the peak of herbivory. Another explanation could be that environmental conditions or processes along the food web are more important in structuring herbivory than leaf traits.
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Keywords: |
Ecuador |
herbivory |
leaf area loss |
plant defense |
plant nutrients |
secondary metabolites |
spectral sensing |
Calvas, B.; Castro, L.M.; Kindu, M.; Bingham, L.; Pintado, K.; Torres Celi, J.; Knoke, T. & Cueva Ortiz, J.L. (2024): Large differences between observed and expected Ecuadorian deforestation from 2001 to 2009: a counterfactual simulation approach. Regional Environmental Change 24, 94.
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DOI: 10.1007/s10113-024-02253-0
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Ensuring the integrity of the world’s forests is indispensable for mitigating climate change, combatting biodiversity loss, and protecting the livelihoods of rural communities. While many strategies have been developed to address deforestation across different geographic scales, measuring their impact against a fluctuating background of market-driven forest loss is notoriously challenging. In this article, we (1) asses deforestation in Ecuador using a dynamic, counterfactual baseline that excludes non-market factors, (2) identify periods of reduced and excess deforestation, and (3) assess the economic consequences
of associated CO2 emissions using the social cost of carbon metric. We construct a counterfactual market-forces-only reference scenario by simulating heterogeneous profit-seeking agents making satisficing land-use allocation decisions under uncertainty. The model simulates a reference scenario for 2001–2022, a period encompassing dollarization, the beginning of a constitution granting inalienable rights to nature, and the launch of the largest payments for ecosystem services program in Ecuador’s history. On this period, total deforestation was approximately 20% lower than expected in a market-forces-only
scenario (9540 vs.12,000 km2). The largest deviation occurred in 2001–2009, when observed deforestation was 43.6% lower than expected (3720 vs 6590 km2).
From 2010 onwards, deforestation appears to be market-driven. We assess the economic value of avoided CO2 emissions at US $5.7 billion if the reduction is permanent, or US $3.1 billion considering a 1% risk of loss from 2022 onwards. We discuss contributing factors that likely shaped periods of reduced and excess deforestation and stress the need to use realistic baselines.
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Keywords: |
land use |
land use change |
land use modeling |
Ecuador, Climate Change, Land Use |
land use/land cover |
Schoen, J.; Tiede, Y.; Becker, M.; Donoso, D.A.; Homeier, J.; Limberger, O.; Bendix, J.; Farwig, N. & Brandl, R. (2023): Effects of leaf traits of tropical trees on the abundance and body mass of herbivorous arthropod communities. PLOS ONE -(-), 1 - 21.
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DOI: 10.1371/journal.pone.0288276
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Abstract:
In tropical forests, herbivorous arthropods remove between 7% up to 48% of leaf area,
which has forced plants to evolve defense strategies. These strategies influence the palat-
ability of leaves. Palatability, which reflects a syndrome of leaf traits, in turn influences both
the abundance and the mean body mass not only of particular arthropod taxa but also of the
total communities. In this study, we tested two hypotheses: (H1) The abundance of two
important chewer guilds (‘leaf chewers’ and ‘rostrum chewers’), dominant components of
arthropod communities, is positively related to the palatability of host trees. (H2) Lower pal-
atability leads to an increased mean body mass of chewers (Jarman-Bell principle). Arthro-
pods were collected by fogging the canopies of 90 tropical trees representing 31 species in
three plots at 1000 m and three at 2000 m a.s.l. Palatability was assessed by measuring
several ‘leaf traits’ of each host tree and by conducting a feeding trial with the generalist her-
bivore Gryllus assimilis (Orthoptera, Gryllidae). Leaf traits provided partial support for H1, as
abundance of leaf chewers but not of rostrum chewers was positively affected by the experi-
mentally estimated palatability. There was no support for H2 as neither leaf traits nor experi-
mentally estimated palatability affected the mean body mass of leaf chewers. The mean
body mass of rostrum chewers was positively related to palatability. Thus, leaf traits and
experimentally estimated palatability influenced the abundance and mean body mass of
chewing arthropods on the community level. However, the data were not consistent with the
Jarman-Bell principle. Overall, our results suggest that the palatability of leaves is not
among the dominant factors influencing abundance and mean body mass of the community of chewing arthropod herbivores. If other factors, such as the microclimate, predation or fur-
ther (a-)biotic interactions are more important has to be analyzed in refined studies.
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Keywords: |
insect herbivores |
abundance |
morphological traits |
leaf functional traits |
Jarman-Bell principle |
leaf chewers |
rostrum chewers |
palatability |
Moses, J.; Peters, M.K.; Tiede, Y.; Mottl, O.; Donoso, D.A.; Farwig, N.; Fayle, T.M.; Novotny, V.; Sanders, N.J. & Klimes, P. (2023): Nutrient use by tropical ant communities varies among three extensive elevational gradients: A cross-continental comparison. Global Ecology and Biogeography n/a(n/a), -.
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DOI: 10.1111/geb.13757
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Abstract Aim Many studies demonstrate that climate limits invertebrates along tropical elevational gradients, but we have only a rudimentary understanding of the role of nutrient limitation and climatic seasonality. Here we examined the relationships between ant community structure, nutrient use and season along three undisturbed elevational gradients, each from a different continent. Location Ecuador (South America), Papua New Guinea (PNG: Oceania), Tanzania (Africa). Time period 2011–2014. Major taxa studied Ants. Methods Along each of the three gradients, we placed six distinct nutrient types (amino acid, sucrose, sucrose + amino acid, lipid, NaCl, H2O). In total, we distributed 2370 baits at 38 sites from 203 m to 3972 m. We used generalized linear models to test for the effects of elevation and season on ant species richness and activity and relative nutrient use. We also tested if changes in ant trophic guilds corresponded to changes in the use of particular nutrients. Results Both species richness and activity decreased with elevation along each gradient. However, there were significant interaction effects among elevation, region and season, as ant activity in the dry season was higher in Ecuador and Tanzania but lower in PNG. Relative nutrient use varied among regions: ant preference for some nutrients changed with increasing elevation in Ecuador (decrease in lipid use) and Tanzania (decrease in amino acid and H2O use), while season affected nutrient use in PNG. There were common trends in trophic guilds along the three elevational gradients (e.g. proportional increase of predators), but these did not explain most of the nutrient use patterns. Main conclusion While the structure of ant communities changed similarly with elevation, both the seasonal and elevational effects on nutrient use by ants differed between continents. We argue that regional differences in climate and nutrient availability rather than ant functional composition shape nutrient use by ants.
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Keywords: |
nutrient use |
Formicidae |
elevational gradients |
feeding preference |
foraging |
functional group |
intercontinental differences |
invertebrates |
seasonal shifts |
tropical forests |
Acosta Rojas, D.C.; Barczyk, M.; Espinosa, C.I.; Farwig, N.; Homeier, J.; Tiede, Y.; Velescu, A.; Tinoco, B.A.; Wilcke, W.; Neuschulz, E.L. & Schleuning, M. (2023): Abiotic factors similarly shape the distribution of fruit, seed and leaf traits in tropical fleshy-fruited tree communities. Acta Oecologica 121, 103953.
Wurz, A.; Bendix, J.; Homeier, J.; Matt, F.; Paladines, P.; Serrano, F. & Farwig, N. (2023): A hidden gem in the Tumbesian dry forest in southern Ecuador: Estacon Cientfica Laipuna. ECOTROPICA 25(1/2), -.
Knoke, T.; Gosling, E.; Reith, E.; Gerique, A.; Pohle, P.; Valle-Carrión, L.A.; Ochoa Moreno, S.; Castro, L.M.; Calvas, B.; Hildebrandt, P.; Döllerer, M.; Bastit, F. & Paul, C. (2022): Confronting sustainable intensification with uncertainty and extreme values on smallholder tropical farms. Sustainability Science 0, 1-18.
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DOI: 10.1007/s11625-022-01133-y
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Abstract:
Sustainable intensification of agricultural lands might reconcile the conservation of tropical forest with food production,but in-depth assessments considering uncertainty and extreme values are missing. Uncertainty prohibits mapping probabilities to potential future states or ranking these states in terms of their likelihood. This in turn hampers the assessment of possible decision outcomes. Here, we use simulations to investigate how uncertainty may influence the social acceptability of alternative land-use strategies to halt tropical deforestation (including sustainable intensification), based on indicators representing farmer satisfaction. The results show how extreme values (worst values) for indicators of farmer satisfaction
may undermine the adoption of sustainable intensification. We demonstrate that a pure forest conservation strategy leads to lower food production, but outperforms a sustainable intensification strategy that maintains food security. Pure forest conservation performed better, i.e., could secure higher farmer satisfaction, than sustainable intensification across a range of indicator groups. This suggests strong barriers to achieving sustainable intensification. Using agricultural subsidies breaks the dominance of pure forest conservation by enhancing the economic returns of sustainable intensification. We discuss the
importance of access to labor and farmers’ preferences for the use of already cleared lands, which achieved the worst values under sustainable intensification and conclude that any assessment of land-use strategies requires careful consideration of uncertainty and extreme values.
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Keywords: |
deforestation |
land use change |
sustainable land use |
agriculture |
land use modeling |
intensification |
Wallis, C.; Tiede, Y.; Beck, E.; Boehning-Gaese, K.; Brandl, R.; Donoso, D.A.; Espinosa, C.; Fries, A.; Homeier, J.; Inclan, D.; Leuschner, C.; Maraun, M.; Mikolajewski, K.; Neuschulz, E.L.; Scheu, S.; Schleuning, M.; Suárez, J.P.; Tinoco, B.A.; Farwig, N. & Bendix, J. (2021): Biodiversity and ecosystem functions depend on environmental conditions and resources rather than the geodiversity of a tropical biodiversity hotspot. Scientific Reports 11(1), 24530.
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DOI: 10.1038/s41598-021-03488-1
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Abstract:
Abstract:
Biodiversity and ecosystem functions are highly threatened by global change. It has been proposed that geodiversity can be used as an easy-to-measure surrogate of biodiversity to guide conservation management. However, so far, there is mixed evidence to what extent geodiversity can predict biodiversity and ecosystem functions at the regional scale relevant for conservation planning. Here, we analyse how geodiversity computed as a compound index is suited to predict the diversity of four taxa and associated ecosystem functions in a tropical mountain hotspot of biodiversity and compare the results with the predictive power of environmental conditions and resources (climate, habitat, soil). We show that combinations of these environmental variables better explain species diversity and ecosystem functions than a geodiversity index and identified climate variables as more important predictors than habitat and soil variables, although the best predictors differ between taxa and functions. We conclude that a compound geodiversity index cannot be used as a single surrogate predictor for species diversity and ecosystem functions in tropical mountain rain forest ecosystems and is thus little suited to facilitate conservation management at the regional scale. Instead, both the selection and the combination of environmental variables are essential to guide conservation efforts to safeguard biodiversity and ecosystem functions.
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Keywords: |
Biodiversity |
geodiversity |
Seibold, S.; Rammer, W.; Hothorn, T.; Seidl, R.; Ulyshen, M.D.; Lorz, J.; Cadotte, M.W.; Lindenmayer, D.B.; Adhikari, Y.P.; Aragón, R.; Bae, S.; Baldrian, P.; Barimani Varandi, H.; Barlow, J.; Bässler, C.; Beauchene, J.; Berenguer, E.; Bergamin, R.S.; Birkemoe, T.; Boros, G.; Brandl, R.; Brustel, H.; Burton, P.J.; Cakpo-Tossou, Y.T.; Castro, J.; Cateau, E.; Cobb, T.P.; Farwig, N.; Fernández, R.D.; Firn, J.; Gan, K.S.; González, G.; Gossner, M.M.; Habel, J.C.; Hébert, C.; Heibl, C.; Heikkala, O.; Hemp, A.; Hemp, C.; Hjältén, J.; Hotes, S.; Kouki, J.; Lachat, T.; Liu, J.; Liu, Y.; Luo, Y.; Macandog, D.M.; Martina, P.E.; Mukul, S.A.; Nachin, B.; Nisbet, K.; O’Halloran, J.; Oxbrough, A.; Pandey, J.N.; Pavlíček, T.; Pawson, S.M.; Rakotondranary, J.S.; Ramanamanjato, J.; Rossi, L.; Schmidl, J.; Schulze, M.; Seaton, S.; Stone, M.J.; Stork, N.E.; Suran, B.; Sverdrup-Thygeson, A.; Thorn, S.; Thyagarajan, G.; Wardlaw, T.J.; Weisser, W.; Yoon, S.; Zhang, N. & Müller, J. (2021): The contribution of insects to global forest deadwood decomposition. Nature 597(7874), 77-81.
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DOI: 10.1038/s41586-021-03740-8
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Abstract:
The amount of carbon stored in deadwood is equivalent to about 8per cent of the global forest carbon stocks1. The decomposition of deadwood is largely governed by climate2–5 with decomposer groups—such as microorganisms and insects—contributing to variations in the decomposition rates2,6,7. At the global scale, the contribution of insects to the decomposition of deadwood and carbon release remains poorly understood7. Here we present a field experiment of wood decomposition across 55 forest sites and 6 continents. We find that the deadwood decomposition rates increase with temperature, and the strongest temperature effect is found at high precipitation levels. Precipitation affects the decomposition rates negatively at low temperatures and positively at high temperatures. As a net effect—including the direct consumption by insects and indirect effects through interactions with microorganisms—insects accelerate the decomposition in tropical forests (3.9% median mass loss per year). In temperate and boreal forests, we find weak positive and negative effects with a median mass loss of 0.9per cent and −0.1per cent per year, respectively. Furthermore, we apply the experimentally derived decomposition function to a global map of deadwood carbon synthesized from empirical and remote-sensing data, obtaining an estimate of 10.93.2petagram of carbon per year released from deadwood globally, with 93per cent originating from tropical forests. Globally, the net effect of insects may account for 29per cent of the carbon flux from deadwood, which suggests a functional importance of insects in the decomposition of deadwood and the carbon cycle.
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Keywords: |
Biodiversity |
Climate and Earth system modelling |
Ecosystem ecology |
Forest ecology |
Limberger, O.; Homeier, J.; Farwig, N.; Pucha-Cofrep, F.; Fries, A.; Leuschner, C.; Trachte, K. & Bendix, J. (2021): Classification of Tree Functional Types in a Megadiverse Tropical Mountain Forest from Leaf Optical Metrics and Functional Traits for Two Related Ecosystem Functions. Forests 12(5), 649.
Tiede, Y.; Hemp, C.; Schmidt, A.; Nauss, T.; Farwig, N. & Brandl, R. (2018): Beyond body size: consistent decrease of traits within orthopteran assemblages with elevation. Ecology 0(0), 1-13.
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DOI: 10.1002/ecy.2436
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Abstract:
Morphological traits provide the interface between species and their environment. For example, body size affects the fitness of individuals in various ways. Yet especially for ectotherms, the applicability of general rules of interspecific clines of body size and even more so of other morphological traits is still under debate. Here we tested relationships between elevation (as a proxy for temperature) and productivity with four ecologically relevant morphological traits of orthopteran assemblages that are related to fecundity (body size), dispersal (wing length), jumping ability (hind femur length), and predator detection (eye size). We measured traits of 160 orthopteran species that were sampled along an extensive environmental gradient at Mt. Kilimanjaro (Tanzania), spanning elevations from 790 to 4,410 m above sea level (a.s.l.) with different levels of plant productivity. For traits other than body size, we calculated the residuals from a regression on body length to estimate the variation of traits irrespective of body size. Bayesian analyses revealed that mean body size of assemblages, as well as the means of relative wing length, hind femur length, and eye size, decreased with increasing elevation. Body size and relative eye size also decreased with increasing productivity. Both phylogenetic relationships, as well as species‐specific adaptations, contributed to these patterns. Our results suggest that orthopteran assemblages had higher fecundity and better dispersal and escape abilities, as well as better predator detection at higher temperatures (low elevations) than at low temperatures (high elevations). Large body sizes might be advantageous in habitats with low productivity because of a reduced risk of starvation. Likewise, large eye size might be advantageous because of the ability to detect predators in habitats with low vegetation cover, where hiding possibilities are scarce. Our study highlights that changes in temperature and productivity not only lead to interspecific changes in body size but are also related to independent changes of other morphological traits that influence the ecological fit of organisms in their environment.
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Keywords: |
body size |
eleva |
morphological traits |
vegetation index |
productivity |
resource availability hypothesis |
Astudillo Webster, P.X.; schabo, D.; Siddons, D. & Farwig, N. (2018): Patch-matrix movements of birds in the páramo landscape of the southern Andes of Ecuador. Emu - Austral Ornithology 67(2), 307-324.
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DOI: 10.13157/arla.67.2.2020.ra5
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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 community at a landscape scale.
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Keywords: |
Paramo |
Polylepis |
bird habitat guilds |
native woody plants |
stepping-stone movements |
Bendix, J.; Aguirre, N.; Beck, E.; Bräuning, A.; Brandl, R.; Breuer, L.; Boehning-Gaese, K.; Dantas De Paula, M.; Hickler, T.; Homeier, J.; Inclan, D.; Leuschner, C.; Neuschulz, E.; Schleuning, M.; Suarez, J.P.; Trachte, K.; Wilcke, W. & Farwig, N. (2021): A research framework for projecting ecosystem change in highly diverse tropical mountain ecosystems. Oecologia 2021, 1-13.
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DOI: 10.1007/s00442-021-04852-8
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Abstract:
Abstract:
Tropical mountain ecosystems are threatened by climate and land-use changes. Their diversity and complexity make projec-
tions how they respond to environmental changes challenging. A suitable way are trait-based approaches, by distinguishing
between response traits that determine the resistance of species to environmental changes and efect traits that are relevant
for species’ interactions, biotic processes, and ecosystem functions. The combination of those approaches with land surface
models (LSM) linking the functional community composition to ecosystem functions provides new ways to project the
response of ecosystems to environmental changes. With the interdisciplinary project RESPECT, we propose a research
framework that uses a trait-based response-efect-framework (REF) to quantify relationships between abiotic conditions,
the diversity of functional traits in communities, and associated biotic processes, informing a biodiversity-LSM. We apply
the framework to a megadiverse tropical mountain forest. We use a plot design along an elevation and a land-use gradient
to collect data on abiotic drivers, functional traits, and biotic processes. We integrate these data to build the biodiversity-
LSM and illustrate how to test the model. REF results show that aboveground biomass production is not directly related to
changing climatic conditions, but indirectly through associated changes in functional traits. Herbivory is directly related to
changing abiotic conditions. The biodiversity-LSM informed by local functional trait and soil data improved the simulation
of biomass production substantially. We conclude that local data, also derived from previous projects (platform Ecuador), are
key elements of the research framework. We specify essential datasets to apply this framework to other mountain ecosystems.
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Keywords: |
Biodiversity-Land-Surface-Model |
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 |
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.
Castro, L.M.; Härtl, F.; Ochoa Moreno, S.; Calvas, B.; Izquierdo Montoya, G.L. & Knoke, T. (2018): Integrated bio-economic models as tools to support land-use decision making: a review of potential and limitations. Journal of Bioeconomics online , online.
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DOI: 10.1007/s10818-018-9270-6
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Abstract:
Abstract:
Bio-economic modelling has become a useful tool for anticipating the
outcomes of policies and technologies before their implementation. Advances in mathematical
programming have made it possible to build more comprehensive models. In
an overview of recent studies about bio-economic models applied to land-use problems
in agriculture and forestry,we evaluated howaspects such as uncertainty,multiple
objective functions, system dynamics and time have been incorporated into models.
We found that single objective models were more frequently applied at the farm level,
while multiple objective modelling has been applied to meet concerns at the landscape
level. Among the objectives, social aspects are seldom represented in allmodels, when
being compared to economic and environmental aspects. The integration of uncertainty
is occasionally a topic, while stochastic approaches are more frequently applied than
non-stochastic robust methods. Mostmultiple-objectivemodels do not integrate uncertainty
or sequential decision making. Static approaches continue to be more recurrent
than truly dynamic models. Even though integrating multiple aspects may enhance
our understanding of a system; it involves a tradeoff between complexity and robustness
of the results obtained. Land-use models have to address this balance between
complexity and robustness in order to evolve towards robust multiple-objective spatial
optimization as a prerequisite to achieve sustainability goals.
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Keywords: |
Uncertainty analysis |
land use modeling |
Bendix, J.; Fries, A.; Zárate, J.; Trachte, K.; Rollenbeck, R.; Pucha Cofrep, F.; Paladines, R.; Palacios, I.; Orellana Alvear, J.; Oñate-Valdivieso, F.; Naranjo, C.; Mendoza, L.; Mejia, D.; Guallpa, M.; Gordillo, F.; Gonzales-Jaramillo, V.; Dobbermann, M.; Celleri, R.; Carrillo, C.; Araque, A. & Achilles, S. (2017): Radarnet Sur – first weather radar network in tropical high mountains. Bulletin of the American Meteorological Society 98(6), 1235-1254.
Wallis, C.; Brehm, G.; Donoso, D.A.; Fiedler, K.; Homeier, J.; Paulsch, D.; Suessenbach, D.; Tiede, Y.; Brandl, R.; Farwig, N. & Bendix, J. (2017): Remote sensing improves prediction of tropical montane species diversity but performance differs among taxa. Ecological Indicators 1(1), 1-10.
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DOI: 10.1016/j.ecolind.2017.01.022
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Abstract:
Abstract:
Texture information from passive remote sensing images provides surrogates for habitat structure, which is relevant for modeling biodiversity across space and time and for developing effective ecological indicators. However, the applicability of this information might differ among taxa and diversity measures. We compared the ability of indicators developed from texture analysis of remotely sensed images to predict species richness and species turnover of six taxa (trees, pyraloid moths, geometrid moths, arctiinae moths, ants, and birds) in a megadiverse Andean mountain rainforest ecosystem. Partial least-squares regression models were fitted using 12 predictors that characterize the habitat and included three topographical metrics derived from a high-resolution digital elevation model and nine texture metrics derived from very high-resolution multi-spectral orthophotos. We calculated image textures derived from mean, correlation, and entropy statistics within a relatively broad moving window (102 m × 102 m) of the near infra-red band and two vegetation indices. The model performances of species richness were taxon dependent, with the lowest predictive power for arctiinae moths (4%) and the highest for ants (78%). Topographical metrics sufficiently modeled species richness of pyraloid moths and ants, while models for species richness of trees, geometrid moths, and birds benefited from texture metrics. When more complexity was added to the model such as additional texture statistics calculated from a smaller moving window (18 m × 18 m), the predictive power for trees and birds increased significantly from 12% to 22% and 13% to 27%, respectively. Gradients of species turnover, assessed by non-metric two-dimensional scaling (NMDS) of Bray-Curtis dissimilarities, allowed the construction of models with far higher predictability than species richness across all taxonomic groups, with predictability for the first response variable of species turnover ranging from 64% (birds) to 98% (trees) of the explained change in species composition, and predictability for the second response variable of species turnover ranging from 33% (trees) to 74% (pyraloid moths). The two NMDS axes effectively separated compositional change along the elevational gradient, explained by a combination of elevation and texture metrics, from more subtle, local changes in habitat structure surrogated by varying combinations of texture metrics. The application of indicators arising from texture analysis of remote sensing images differed among taxa and diversity measures. However, these habitat indicators improved predictions of species diversity measures of most taxa, and therefore, we highly recommend their use in biodiversity research.
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Keywords: |
moths |
species richness |
species turnover |
mountain rainforest |
tropical trees |
Birds |
ants |
orthophotos |
Tiede, Y.; Schlautmann, J.; Donoso, D.A.; Wallis, C.; Bendix, J.; Brandl, R. & Farwig, N. (2017): Ants as indicators of environmental change and ecosystem processes. Ecological indicators 1(1), 1-6.
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DOI: 10.1016/j.ecolind.2017.01.029
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Abstract:
Abstract:
Environmental stressors and changes in land use have led to rapid and dramatic species losses. As such, we need effective monitoring programs that alert us not only to biodiversity losses, but also to functional changes in species assemblages and associated ecosystem processes. Ants are important components of terrestrial food webs and a key group in food web interactions and numerous ecosystem processes. Their sensitive and rapid response to environmental changes suggests that they are a suitable indicator group for the monitoring of abiotic, biotic, and functional changes. We tested the suitability of the incidence (i.e. the sum of all species occurrences at 30 baits), species richness, and functional richness of ants as indicators of ecological responses to environmental change, forest degradation, and of the ecosystem process predation on herbivorous arthropods. We sampled data along an elevational gradient (1000–3000 m a.s.l.) and across seasons (wetter and drier period) in a montane rainforest in southern Ecuador. The incidence of ants declined with increasing elevation but did not change with forest degradation. Ant incidence was higher during the drier season. Species richness was highly correlated with incidence and showed comparable results. Functional richness also declined with increasing elevation and did not change with forest degradation. However, a null-model comparison revealed that the functional richness pattern did not differ from a pattern expected for ant assemblages with randomly distributed sets of traits across species. Predation on artificial caterpillars decreased along the elevational gradient; the pattern was not driven by elevation itself, but by ant incidence (or inter-changeable by ant richness), which positively affected predation. In spite of lower ant incidence (or ant richness), predation was higher during the wetter season and did not change with forest degradation and ant functional richness. We used path analysis to disentangle the causal relationships of the environmental factors temperature (with elevation as a proxy), season, and habitat degradation with the incidence and functional richness of ants, and their consequences for predation. Our results would suggest that the forecasted global warming might support more active and species-rich ant assemblages, which in turn would mediate increased predation on herbivorous arthropods. However, this prediction should be made with reservation, as it assumes that the dispersal of ants keeps pace with the climatic changes as well as a one-dimensional relationship between ants and predation within a food-web that comprises species interactions of much higher complexity. Our results also suggested that degraded forests in our study area might provide suitable habitat for epigaeic, ground-dwelling ant assemblages that do not differ in incidence, species richness, functional richness, composition, or predation on arthropods from assemblages of primary forests. Most importantly, our results suggest that the occurrence and activity of ants are important drivers of ecosystem processes and that changes in the incidence and richness of ants can be used as effective indicators of responses to temperature changes and of predation within mega-diverse forest ecosystems.
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Keywords: |
elevational gradient |
species traits |
forest degradation |
path model |
artificial caterpillars |
functional richness |
Farwig, N.; Bendix, J. & Beck, E. (2017): Introduction to the Special Issue “Functional monitoring in megadiverse tropical ecosystems”. Ecological indicators 1(1), 1-3.
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DOI: 10.1016/j.ecolind.2017.02.027
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Abstract:
Abstract:
Land-use and climate change are major threats to biodiversity and ecosystem functions. Most of the current biodiversity monitoring systems are based on periodic records of the populations of a set of threatened or popular ‘flagship’ indicator species. In contrast to the abundance-based monitoring of species, also specific indicators of processes and functional interactions in an ecosystem may become targets of a more functional monitoring which can unveil early responses of an ecosystem to environmental changes at different spatial and temporal scales. The contributions of this Special Issue present such functional indicators for assessing and predicting responses to environmental changes of ecosystem functions in a hotspot of tropical biodiversity.
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Keywords: |
Ecuador |
ecosystem services |
Biodiversity |
ecosystem functions |
global change effects |
functional monitoring systems |
Tiede, Y.; Homeier, J.; Cumbicus Torres, N.; Pena Tamayo, J.E.; Albrecht, J.; Ziegenhagen, B.; Bendix, J.; Brandl, R. & Farwig, N. (2016): Phylogenetic niche conservatism does not explain elevational patterns of species richness, phyodiversity and family age of tree assemblages in Andean rainforest. Erdkunde 70(1), 83-106.
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DOI: 10.3112/erdkunde.2016.01.06
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Abstract:
Abstract:
Phylogenetic niche conservatism (PNC) is the tendency of species within a clade to retain ancestral traits and
to persist in their primary ecological niches on geological time scales. It links evolutionary and ecological processes and has
been hypothesized to explain patterns of species richness and the composition of species assemblages. Decreasing patterns
of species richness along latitudinal gradients were often explained by the combination of ancient tropical climates, trait
retention of tropical lineages and environmental filtering. PNC also predicts decreasing phylodiversity and family age with
decreasing tropicality and has been invoked to explain these patterns along climatic gradients across latitudinal as well as elevational
gradients.
However,
recent
studies
on
tree
assemblages
along
latitudinal
and
elevational
gradients
in
South
America
found
patterns
contradicting
the
PNC
framework.
Our
study
aims
to
shed
light
on
these
contradictions
using
three
different
metrics of the phylogenetic composition that form a gradient from recent evolutionary history to deep phylogenetic
relationships. We analyzed the relationships between elevation and taxonomic species richness, phylodiversity and family
age of tree assemblages in Andean rainforests in Ecuador. In contrast to predictions of the PNC we found no associations
of elevation with species richness of trees and increasing clade level phylodiversity and family age of the tree assemblages
with elevation. Interestingly, we found that patterns of phylodiversity across the studied elevation gradient depended especially
on
the
deep
nodes
in
the
phylogeny.
We
therefore
suggest
that
the
dispersal
of
evolutionarily old plant lineages with
extra-tropical origins influences the recent composition of tree assemblages in the Andes. Further studies spanning broader
ecological gradients and using better resolved phylogenies to estimate family and species ages are needed to obtain a deeper
mechanistic understanding of the processes that drive the assembly of tree communities along elevational gradients.
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Keywords: |
Ecuador |
vegetation geography |
tree species assembly |
elevational gradient |
orogeny |
Knoke, T.; Paul, C.; Hildebrandt, P.; Calvas, B.; Castro, L.M.; Härtl, F.; Döllerer, M.; Hamer, U.; Windhorst, D.; Wiersma, Y.; Curatola Fernández, G.F.; Obermeier, W.A.; Adams, J.; Breuer, L.; Mosandl, R.; Beck, E.; Weber, M.; Stimm, B.; Haber, W.; Fürst, C. & Bendix, J. (2016): Compositional diversity of rehabilitated tropical lands supports multiple ecosystem services and buffers uncertainties. Nature Communications 7, Article number:11877.
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DOI: 10.1038/ncomms11877
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Abstract:
Abstract:
High landscape diversity is assumed to increase the number and level of ecosystem services. However, the interactions between ecosystem service provision, disturbance and landscape composition are poorly understood. Here we present a novel approach to include uncertainty in the optimization of land allocation for improving the provision of multiple ecosystem services. We refer to the rehabilitation of abandoned agricultural lands in Ecuador including two types of both afforestation and pasture rehabilitation, together with a succession option. Our results show that high compositional landscape diversity supports multiple ecosystem services (multifunction effect). This implicitly provides a buffer against uncertainty. Our work shows that active integration of uncertainty is only important when optimizing single or highly correlated ecosystem services and that the multifunction effect on landscape diversity is stronger than the uncertainty effect. This is an important insight to support a land-use planning based on ecosystem services.
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Keywords: |
ecosystem services |
South Ecuador |
sustainable land use |
land use modeling |
restoration |
Wallis, C.; Paulsch, D.; Zeilinger, J.; Silva, B.; Curatola Fernández, G.F.; Brandl, R.; Farwig, N. & Bendix, J. (2016): Contrasting performance of Lidar and optical texture models in predicting avian diversity in a tropical mountain forest. Remote sensing of environment 174, 223-232.
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DOI: 10.1016/j.rse.2015.12.019
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Abstract:
Abstract:
Ecosystems worldwide are threatened by the increasing impact of land use and climate change. To protect their diversity and functionality, spatially explicit monitoring systems are needed. In remote areas, monitoring is difficult and recurrent field surveys are costly. By using Lidar or themore cost-effective and repetitive optical satellite data, remote sensing could provide proxies for habitat structure supporting measures for the conservation of biodiversity. Here we compared the explanatory power of both, airborne Lidar and optical satellite data in modeling the spatial distribution of biodiversity of birds across a complex tropical mountain forest ecosystem in southeastern Ecuador. Weused data fromfield surveys of birds and chose three measures as proxies for different aspects of diversity: (i) Shannon diversity as a measure of ?-diversity that also includes the relative abundance of species, (ii) phylodiversity as a first proxy for functional diversity, and (iii) community composition as a proxy for combined ?- and ?-diversity.We modeled these diversity estimates using partial least-square regression of Lidar and optical texturemetrics separately and compared themodels using a leave-one-out validated R2 and rootmean square error. Bird community informationwas best predicted by both remote sensing datasets, followed by Shannon diversity and phylodiversity. Our findings reveal a high potential of optical texture metrics for predicting Shannon diversity and ameasure of community composition, but not for modeling phylodiversity.
Generalizing from the investigated tropicalmountain ecosystem,we conclude that texture information retrieved frommultispectral data of operational satellite systems could replace costly airborne laser-scanning formodeling certain aspects of biodiversity.
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Keywords: |
forest structure |
LiDAR |
QuickBird |
topographic heterogenity |
bird community |
Birds |
Wallis, C.; Paulsch, D.; Zeilinger, J.; Silva, B.; Curatola Fernández, G.F.; Brandl, R.; Farwig, N. & Bendix, J. (2016): Contrasting performance of Lidar and optical texture models in predicting avian diversity in a tropical mountain forest. Remote Sensing of Environment 174, 223-232.
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DOI: 10.1016/j.rse.2015.12.019
-
Abstract:
Abstract:
Ecosystems worldwide are threatened by the increasing impact of land use and climate change. To protect their diversity and functionality, spatially explicit monitoring systems are needed. In remote areas, monitoring is difficult and recurrent field surveys are costly. By using Lidar or themore cost-effective and repetitive optical satellite data, remote sensing could provide proxies for habitat structure supporting measures for the conservation of biodiversity. Here we compared the explanatory power of both, airborne Lidar and optical satellite data in modeling the spatial distribution of biodiversity of birds across a complex tropical mountain forest ecosystem in southeastern Ecuador. Weused data fromfield surveys of birds and chose three measures as proxies for different aspects of diversity: (i) Shannon diversity as a measure of ?-diversity that also includes the relative abundance of species, (ii) phylodiversity as a first proxy for functional diversity, and (iii) community composition as a proxy for combined ?- and ?-diversity.We modeled these diversity estimates using partial least-square regression of Lidar and optical texturemetrics separately and compared themodels using a leave-one-out validated R2 and rootmean square error. Bird community informationwas best predicted by both remote sensing datasets, followed by Shannon diversity and phylodiversity. Our findings reveal a high potential of optical texture metrics for predicting Shannon diversity and ameasure of community composition, but not for modeling phylodiversity.
Generalizing from the investigated tropical mountain ecosystem, we conclude that texture information retrieved frommultispectral data of operational satellite systems could replace costly airborne laser-scanning formodeling certain aspects of biodiversity.
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Keywords: |
Biodiversity |
Southern Ecuador |
beta diversity |
Lidar |
Quickbird |
Phylodiversity |
Alpha diversity |
Shannon diversity |
Community composition |
Birds |
Partial least-square regression |
Gray level co-occurrence matrix |
Knoke, T.; Paul, C.; Härtl, F.; Castro, L.M.; Calvas, B. & Hildebrandt, P. (2015): Optimizing agricultural land-use portfolios with scarce data—A non-stochastic model. Ecological Economics 120, 250-259.
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DOI: 10.1016/j.ecolecon.2015.10.021
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Abstract:
Abstract:
The theory of portfolio selection has often been applied to help improving decisions on the environment. The information required to apply this theory includes data on covariance of the uncertain returns between all combinations of the economic options and normally distributed returns. As it may be problematic to fulfil all data requirements and assumptions, the paper proposes a variant of robust portfolio optimization as an alternative. It considers future uncer-tainties in a non-stochastic fashion by means of possible deviations from the nominal return of land-use alternatives. The maximization of the economic return of the land-use portfolio is conditional to meeting an inclusive set of constraints. These demand that the same, whenever possible high, proportion of a required return threshold is achieved by means of the robust solution for each deviation scenario considered. The paper compares the land-use portfolios derived non-stochastically with portfolios generated by classical stochastic mean-variance op-timization. Based on data for eight agricultural crops typical for the Ecuadorian lowlands the results show that, depending on the deviation scenario assumed, the robust portfolios show a greater Shannon index compared to classical portfolios. For the same standard deviation of returns (derived through the classical sum of all covariances) the robust portfolios show no more than 2-5% loss in economic return in most cases. Occasionally, the loss has been higher, up to 20%. In this case the Shannon index was about 2.5 times higher compared with that of the conventional portfolio. The highly diverse portfolio achieved a much better protection against low relative performance. The results obtained show that the non-stochastic derivation of land-use portfolios is a good alternative to the classical stochastic model, whenever eco-nomic information is scarce.
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Keywords: |
land use |
diversification |
sustainable land use |
land use modeling |
Portfolio Theory |
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.
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DOI: 10.1371/journal.pone.0120384
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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.
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Keywords: |
land diversification |
agriculture |
land use modeling |
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.
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DOI: 10.1080/01650521.2014.960778
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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.
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Keywords: |
Paramo |
species richness |
abundance |
bird community |
stressors |
Cajas National Park |
road impact |