Publications
Found 510 publication(s)
- of type article
Cueva, A.; Manchego, C.; Bastidas, C. & Curto, M. (2021): Development and characterization of microsatellite markers for two subspecies of Handroanthus chrysanthus. Rodriguésia 72(e00722020), 6.
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DOI: 10.1590/2175-7860202172088
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Abstract:
Abstract:
An understanding of the genetic diversity and structure of plant species is essential in order to comprehend the degree of biodiversity loss and to develop successful restoration programs. Handroanthus is an important genus that presents one of the most valuable timbers of South America. Handroanthus chrysanthus is an important species distributed in Central and South America. Microsatellite markers are not previously developed for this species. Ten microsatellites for Handroanthus chrysanthus developed using high-throughput sequencing are presented here. The usefulness of these microsatellite loci for the genetic analysis of subspecies H. chrysanthus subsp. chrysanthus (distributed in coastal dry forests) and subspecies H. chrysanthus subsp. meridionalis (distributed in premontane moist forests) is analyzed. At least eight polymorphic microsatellites are useful for each subspecies, seven of which can be used in both subspecies.
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Keywords: |
Ecuador |
dry forest |
Handroanthus chrysanthus |
Guayacan |
microsatellites |
premontane forest |
subspecies |
Vollstaedt, M.; Albrecht, J.; Boehning-Gaese, K.; Hemp, C.; Howell, K.; Kettering, L.; Neu, A.; Neuschulz, E.; Quitian, M.; Santillan, V.; Töpfer, T.; Schleuning, M. & Fritz, S. (2020): Direct and plant-mediated effects of climate on bird diversity in tropical mountains. Ecology and Evolution 10(24), 14196-14208.
Dehling, D.; Bender, I.M.; Blendinger, P.; Boehning-Gaese, K.; Munoz, M.; Neuschulz, E.; Quitian, M.; Saavedra, F.; Santillan, V.; Schleuning, M. & stouffer, D. (2021): Specialists and generalists fulfil important and complementary functional roles in ecological processes. Functional Ecology 35(8), 1810-1821.
Velescu, A.; Homeier, J.; Bendix, J.; Valarezo, C. & Wilcke, W. (2021): Response of water-bound fluxes of potassium, calcium, magnesium and sodium to nutrient additions in an Ecuadorian tropical montane forest. Forest Ecology and Management 501(119661), 1-14.
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DOI: 10.1016/j.foreco.2021.119661
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Abstract:
Abstract:
In the past two decades, the Amazon-exposed, tropical montane rain forests in south Ecuador experienced increasing deposition of reactive N mainly from Amazonian forest fires, episodic Ca and Mg inputs from Saharan dust, and a low but constant P deposition from unknown sources. To explore the response of this tropical, perhumid ecosystem to nutrient inputs, we established in 2007 a Nutrient Manipulation Experiment (NUMEX). Since 2008, we have applied 50 kg ha−1 year−1 of N as urea, 10 kg ha−1 year−1 of P as NaH2PO4·H2O, 50 kg ha−1 year−1 of N + 10 kg ha−1 year−1 of P and 10 kg ha−1 year−1 of Ca as CaCl2·H2O in a randomized block design at 2000 m a.s.l. in a natural forest of the south Ecuadorian Andes. Previous studies have shown that alkali and alkaline earth metals had beneficial effects on the functioning of N and P co-limited tropical forests occurring on acidic soils. Therefore, we determined the response of all major aqueous ecosystem fluxes of K, Ca, Mg and Na to nutrient amendments, to understand how increasing atmospheric deposition would affect their cycling in the future. Additions of N and P decreased K leaching from the organic layer and in the mineral soil, thus tightening K cycling. This suggests that increasing future N and P availability may result in K limitation in the long term. The leaching of Ca and Mg from the canopy increased in response to amendments of N and P and we observed an enhanced uptake of these nutrients also if Ca was amended alone. Although N was applied as urea, acidity of soil solutions and leaching of K, Ca, Mg and Na did not increase following separate N amendments. In spite of the acid soils and of its low cation-exchange competitivity, Na included in the P fertilizer was only partly leached from the organic layer. We suggest that it was probably required to cover an unmet Na demand of the soil fauna. Our results demonstrate the major role in the functioning of the tropical montane forests played by K, Ca and Mg as potential future growth-limiting elements and increasingly required nutrients in response to rising N and P availability, while they also support the importance of Na as a functional element in these ecosystems.
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Keywords: |
Ecuador |
NUMEX |
nutrient manipulation |
tropical montane forest |
nutrient additions |
base cations |
Dantas De Paula, M.; Forrest, M.; Langan, L.; Bendix, J.; Homeier, J.; Velescu, A.; Wilcke, W. & Hickler, T. (2021): Nutrient cycling drives plant community trait assembly and ecosystem functioning in a tropical mountain biodiversity hotspot. New Phytologist -(-), -.
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DOI: 10.1111/nph.17600
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Abstract:
Summary Community trait assembly in highly diverse tropical rainforests is still poorly understood. Based on more than a decade of field measurements in a biodiversity hotspot of southern Ecuador, we implemented plant trait variation and improved soil organic matter dynamics in a widely used dynamic vegetation model (the Lund-Potsdam-Jena General Ecosystem Simulator, LPJ-GUESS) to explore the main drivers of community assembly along an elevational gradient. In the model used here (LPJ-GUESS-NTD, where NTD stands for nutrient-trait dynamics), each plant individual can possess different trait combinations, and the community trait composition emerges via ecological sorting. Further model developments include plant growth limitation by phosphorous (P) and mycorrhizal nutrient uptake. The new model version reproduced the main observed community trait shift and related vegetation processes along the elevational gradient, but only if nutrient limitations to plant growth were activated. In turn, when traits were fixed, low productivity communities emerged due to reduced nutrient-use efficiency. Mycorrhizal nutrient uptake, when deactivated, reduced net primary production (NPP) by 61–72% along the gradient. Our results strongly suggest that the elevational temperature gradient drives community assembly and ecosystem functioning indirectly through its effect on soil nutrient dynamics and vegetation traits. This illustrates the importance of considering these processes to yield realistic model predictions.
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Keywords: |
mycorrhiza |
dynamic vegetation model |
nutrient cycling |
plant community assembly |
plant functional traits |
tropical montane forests (TMF) |
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:
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 |
Haug, I.; Setaro, S. & Suárez, J.P. (2021): Global AM fungi are dominating mycorrhizal communities in a tropical premontane dry forest in Laipuna, South Ecuador. Mycological Progress 20(6), 837-845.
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DOI: 10.1007/s11557-021-01699-4
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Abstract:
Abstract:
Tropical dry forests are an intricate ecosystem with special adaptations to periods of drought. Arbuscular mycorrhizal fungi (AMF) are essential for plant survival in all terrestrial ecosystems but might be of even greater importance in dry forests as plant growth is limited due to nutrient and water deficiency during the dry season. Tropical dry forests in Ecuador are highly endangered, but studies about AMF communities are scarce. We investigated the AMF community of a premontane semi-deciduous dry forest in South Ecuador during the dry season. We estimated AMF diversity, distribution, and composition of the study site based on operational taxonomic units (OTUs) and compared the results to those from the tropical montane rainforest and páramo in South Ecuador. OTU delimitation was based on part of the small ribosomal subunit obtained by cloning and Sanger sequencing. Nearly all OTUs were Glomeraceae. The four frequent OTUs were Glomus, and comparison with the MaarjAM database revealed these to be globally distributed with a wide range of ecological adaptations. Several OTUs are shared with virtual taxa from dry forests in Africa. Ordination analysis of AMF communities from the tropical dry and montane rainforests in South Ecuador revealed a unique AMF community in the dry forest with only few overlapping OTUs. Most OTUs that were found in both dry and rainforests and on the two continents were globally distributed Glomus.
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Keywords: |
ecuador |
AMF community |
Tropical dry forest |
Sanger sequencing |
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.
Homeier, J.; Seeler, T.; Pierick, K. & Leuschner, C. (2021): Leaf trait variation in species-rich tropical Andean forests. Scientific Reports 11, 9993.
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DOI: 10.1038/s41598-021-89190-8
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Abstract:
Abstract:
Screening species-rich communities for the variation in functional raits along environmental gradients may help understanding the abiotic drivers of plant performance in a mechanistic way. We investigated tree leaf trait variation along an elevation gradient (1000–3000 m) in highly diverse neotropical montane forests to test the hypothesis that elevational trait change reflects a trend toward more conservative resource use strategies at higher elevations, with interspecific trait variation decreasing and trait integration increasing due to environmental filtering. Analysis of trait variance partitioning across the 52 tree species revealed for most traits a dominant influence of phylogeny, except for SLA, leaf thickness and foliar Ca, where elevation was most influential. The community-level means of SLA, foliar N and Ca, and foliar N/P ratio decreased with elevation, while leaf thickness and toughness increased. The contribution of intraspecific variation was substantial at the community level in most traits, yet smaller than the interspecific component. Both within-species and between-species trait variation did not change systematically with elevation. High phylogenetic diversity, together with small-scale edaphic heterogeneity, cause large interspecific leaf trait variation in these hyper-diverse Andean forests. Trait network analysis revealed increasing leaf trait integration with elevation, suggesting stronger environmental filtering at colder and nutrient-poorer sites.
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Keywords: |
leaf functional traits |
Urgilés, G.; Celleri, R.; Trachte, K.; Bendix, J. & Orellana-Alvear, J. (2021): Clustering of Rainfall Types Using Micro Rain Radar and LaserDisdrometer Observations in the Tropical Andes. Remote Sensing 13(5), 1-22.
Homeier, J. & Leuschner, C. (2021): Factors controlling the productivity of tropical Andean forests: climate and soil are more important than tree diversity. Biogeosciences 18(4), 1524-1541.
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DOI: 10.5194/bg-18-1525-2021
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Abstract:
Abstract:
Theory predicts positive effects of species richness on the productivity of plant communities through complementary resource use and facilitative interactions between species. Results from manipulative experiments with tropical tree species indicate a positive diversity–productivity relationship (DPR), but the existing evidence from natural forests
is scarce and contradictory. We studied forest aboveground productivity in more than 80 humid tropical montane oldgrowth forests in two highly diverse Andean regions with large geological and topographic heterogeneity and related productivity to tree diversity and climatic, edaphic and stand
structural factors with a likely influence on productivity. Main determinants of wood production in the perhumid study regions were elevation (as a proxy for temperature), soil nutrient (N, P and base cation) availability and forest structural parameters (wood specific gravity, aboveground biomass). Tree diversity had only a small positive influence on productivity, even though tree species numbers varied largely (6–27 species per 0.04 ha). We conclude that the productivity of highly diverse Neotropical montane forests is primarily controlled by thermal and edaphic factors and stand structural properties, while tree diversity is of minor importance.
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Keywords: |
soil nutrients |
wood production |
tropical montane forest |
elevational gradient |
Aboveground forest productivity |
Turini, N.; Thies, B.; Horna, N. & Bendix, J. (2021): Random forest-based rainfall retrieval for Ecuador using GOES-16 and IMERG-V06 data. European Journal of Remote Sensing 54(1), 117-139.
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DOI: 10.1080/22797254.2021.1884002
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Abstract:
Abstract:
A new satellite-based algorithm for rainfall retrieval in high spatio-temporal resolution fo
Ecuador is presented. The algorithm relies on the precipitation information from the Integrated
Multi-SatEllite Retrieval for the Global Precipitation Measurement (GPM) (IMERG) and infrared
(IR) data from the Geostationary Operational Environmental Satellite-16 (GOES-16). It wa
developed to (i) classify the rainfall area (ii) assign the rainfall rate. In each step, we selected
the most important predictors and hyperparameter tuning parameters monthly. Between 19
April 2017 and 30 November 2017, brightness temperature derived from the GOES-16 IR
channels and ancillary geo-information were trained with microwave-only IMERG-V06 using
random forest (RF). Validation was done against independent microwave-only IMERG-V06
information not used for training. The validation results showed the new rainfall retrieva
technique (multispectral) outperforms the IR-only IMERG rainfall product. This offers using
the multispectral IR data can improve the retrieval performance compared to single-spectrum
IR approaches. The standard verification scored a median Heidke skill score of ~0.6 for the rain
area delineation and R between ~0.5 and ~0.62 for the rainfall rate assignment, indicating
uncertainties for Andes’s high elevation. Comparison of RF rainfall rates in 2 km2
resolution
with daily rain gauge measurements reveals the correlation of R = ~0.33.
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Keywords: |
random forest |
rainfall |
GOES |
Quiroz Dahik, C.; Crespo, P.; Stimm, B.; Mosandl, R.; Cueva Ortiz, J.L.; Hildebrandt, P. & Weber, M. (2021): Impacts of pine plantations on carbon stocks of páramo sites in southern Ecuador. Carbon Balance and Management 16(5), 15 pp.
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DOI: 10.1186/s13021-021-00168-5
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Abstract:
Abstract:
Background: Since the 1990’s, afforestation programs in the páramo have been implemented to offset carbon emissions through carbon sequestration, mainly using pine plantations. However, several studies have indicated that after the establishment of pine plantations in grasslands, there is an alteration of carbon pools including a decrease of the soil organic carbon (SOC) pool. The aim of this study is to investigate the impact of the establishment of pine plantations on the carbon stocks in different altitudes of the páramo ecosystem of South Ecuador.
Results: At seven locations within an elevational gradient from 2780 to 3760 m a.s.l., we measured and compared carbon stocks of three types of land use: natural grassland, grazed páramo, and Pinus patula Schlltdl. & Cham. plantation sites. For a more accurate estimation of pine tree carbon, we developed our own allometric equations. There were significant (p < 0.05) differences between the amounts of carbon stored in the carbon pools aboveground and belowground for the three types of land use. In most of the locations, pine plantations revealed the highest amounts of aboveground and belowground carbon (55.4 and 6.9 tC/ha) followed by natural grassland (23.1 and 2.7 tC/ha) and grazed páramo sites (9.1 and 1.5 tC/ha). Concerning the SOC pools, most of the locations revealed significant lower values of plantations’ SOC in comparison to natural grassland and grazed páramo sites. Higher elevation was associated with lower amounts of pines’ biomass.
Conclusions: Even though plantations store high amounts of carbon, natural páramo grassland can also store substantial
amounts above and belowground, without negatively affecting the soils and putting other páramo ecosystem services at risk. Consequently, plans for afforestation in the páramo should be assessed case by case, considering not only the limiting factor of elevation, but also the site quality especially affected by the type of previous land use.
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Keywords: |
aboveground biomass |
land use change |
soil organic carbon |
carbon sequestration |
carbon pools |
belowground biomass |
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:
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 |
Contreras, P.; Orellana-Alvear, J.; Muñoz, P.; Bendix, J. & Celleri, R. (2021): Influence of Random Forest Hyperparameterization on Short-Term Runoff Forecasting in an Andean Mountain Catchment. Atmosphere 12(2), 1-16.
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DOI: 10.3390/atmos12020238
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Abstract:
Abstract:
The Random Forest (RF) algorithm, a decision-tree-based technique, has become a promising approach for applications addressing runoff forecasting in remote areas. This machine learning approach can overcome the limitations of scarce spatio-temporal data and physical parameters needed for process-based hydrological models. However, the influence of RF hyperparameters is still uncertain and needs to be explored. Therefore, the aim of this study is to analyze the sensitivity of RF runoff forecasting models of varying lead time to the hyperparameters of the algorithm. For this, models were trained by using (a) default and (b) extensive hyperparameter combinations through a grid-search approach that allow reaching the optimal set. Model performances were assessed based on the R2, %Bias, and RMSE metrics. We found that: (i) The most influencing hyperparameter is the number of trees in the forest, however the combination of the depth of the tree and the number of features hyperparameters produced the highest variability-instability on the models. (ii) Hyperparameter optimization significantly improved model performance for higher lead times (12- and 24-h). For instance, the performance of the 12-h forecasting model under default RF hyperparameters improved to R2 = 0.41 after optimization (gain of 0.17). However, for short lead times (4-h) there was no significant model improvement (0.69 < R2 < 0.70). (iii) There is a range of values for each hyperparameter in which the performance of the model is not significantly affected but remains close to the optimal. Thus, a compromise between hyperparameter interactions (i.e., their values) can produce similar high model performances. Model improvements after optimization can be explained from a hydrological point of view, the generalization ability for lead times larger than the concentration time of the catchment tend to rely more on hyperparameterization than in what they can learn from the input data. This insight can help in the development of operational early warning systems.
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Keywords: |
Ecuador |
discharge |
random forest |
water fluxes |
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 |
Núñez, P.Á.; Silva, B.; Schulz, M.; Rollenbeck, R. & Bendix, J. (2021): Evapotranspiration estimates for two tropical mountain forest using high spatial resolution satellite data. International Journal of Remote Sensing 42(8), 2940--2962.
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DOI: 10.1080/01431161.2020.1864058
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Abstract:
Abstract:
Tropical Mountain Forest (TMF) provides important ecological functions like evapotranspiration (ET) that supplies moisture and energy to the atmosphere. ET observations are scarce and difficult to accomplish particularly in areas of high heterogeneity where TMF are. Remote sensing (RS) allows to quantify and to determine ET spatial variation at the landscape level. Detail imaginary improves high spatial variability retrieval. Thought the greater detail introduces cast shadows by trees which hamper image interpretation. The objective of this study is to characterize ET estimation for the TMF of the southern Ecuadorian Andes by combining meteorological data with high-resolution satellite images. Shadows from high resolution images were masked out by applying focal statistics. The analysis included two meteorological periods typical of the area; a wet period when rain prevails and a dry period when precipitation is more sporadic. The reference evapotranspiration (ET0) was calculated using the FAO-Penman Montheid method by applying data obtained from an automatic weather station. The enhanced vegetation index (EVI) was derived from 2 m resolution WorldView2 satellite images. Results showed a lower ET mean value during the wet period: 1.54 mm day−1 compared to 2.37 mm day−1. Two forest types, differentiated from its structural composition and topographical position (ravine and ridge), marked ET spatial variation. Ravine forest that has a more dense and closed canopy showed higher ET values for both meteorological conditions. A comparison between ET estimations and ET field measurements from a scintillometer device showed a good agreement (coefficient of correlation r = 0.89) that proves the validity of the method. This study demonstrates that the application of high spatial resolution improves ET estimation in TMF especially when shadows are removed. Also, emphasizes the importance of analysing spatial heterogeneity to properly assess ecosystem water flux terms.
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Keywords: |
remote sensing |
mountain rainforest |
Evapotranspiration |
Landshuter, N.; Mölg, T.; Grießinger, J.; Bräuning, A.; Peters, T. & Institute of Geography, F.E.E.G. (2020): Characteristics of moisture source regions and their potential effect on seasonal isotopic signatures of d18O in tropical trees of southern Ecuador. Frontiers in Earth Science 8(604804), 1-22.
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DOI: 10.3389/feart.2020.604804
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Abstract:
Abstract:
Ratios of stable oxygen isotopes in tree rings (δ18O) are a valuable proxy for reconstructing past climates. Such reconstructions allow us to gain better knowledge of climate dynamics under different (eg warmer) environmental conditions, which also forms the basis for effective risk management. The latter aspect is particularly relevant for our study site on the
western flanks of the Andes in Southern Ecuador, since the region is frequently affected by droughts and heavy precipitation events during the rainy season (January to April), leading to enormous social and economic losses. In particular, we focus on precipitation amounts and moisture source regions as they are known to influence the δ18O signature of tree rings. Moisture source regions are based on 240 h backward trajectories that were
calculated with the trajectory model LAGRANTO for the rainy seasons 2008 to 2017. A moisture source diagnostic was applied to the air parcel pathways. The resulting moisture source regions were analyzed by calculating composites based on precipitation amounts, season, and calendar year. The precipitation amounts were derived from data of a local Automatic Weather Station (AWS). The analysis confirms that our study site receives its moisture both, from the Atlantic and the Pacific Oceans.
Heavy precipitation events are linked to higher moisture contributions from the Pacific, and local SST anomalies along the coast of Ecuador are of higher importance than those off the coast toward the central Pacific. Moreover, we identified increasing moisture contributions from the Pacific over the course of the rainy season. This change and also rain amount
effects are detectable in preliminary data of δ18O variations in tree rings of Bursera graveolens. These signatures can be a starting point for investigating atmospheric and hydroclimatic processes, which trigger δ18O variations in tree rings, more extensively in future studies.
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Keywords: |
precipitation |
South Ecuador |
South America |
tropical trees |
Tree Rings |
modelling |
stable isotopes |
Pierick, K.; Leuschner, C. & Homeier, J. (2021): Topography as a factor driving small‐scale variation in tree fine root traits and root functional diversity in a species‐rich tropical montane forest. New Phytologist 230(1), 129-138.
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DOI: 10.1111/nph.17136
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Abstract:
Abstract:
(1) We investigated the variation in tree fine root traits and their functional diversity along a local topographic gradient in a Neotropical montane forest to test if fine root trait variation along the gradient is consistent with the predictions of the root economics spectrum on a shift from acquisitive to conservative traits with decreasing resource supply.
(2) We measured five fine root functional traits in 179 randomly selected tree individuals of 100 species and analyzed the variation of single traits (using Bayesian phylogenetic multi‐level models) and of functional trait diversity with small scale topography.
(3) Fine roots exhibited more conservative traits (thicker diameters, lower specific root length and nitrogen concentration) at upper slope compared to lower slope positions, but the largest proportion of variation (40‐80%) was explained by species identity and phylogeny. Fine root functional diversity decreased towards the upper slopes.
(4) Our results suggest that local topography and the related soil fertility and moisture gradients cause considerable small‐scale variation in fine root traits and functional diversity along tropical mountain slopes, with conservative root traits and greater trait convergence being associated with less favorable soil conditions due to environmental filtering. We provide evidence of a high degree of phylogenetic conservation in fine root traits.
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Keywords: |
Ecuador |
tropical montane forest |
root functional traits |
root economics spectrum |
phylogenetic regression |
functional dispersion |
Bayesian multi-level models |
Wilcke, W.; Velescu, A.; Leimer, S.; Blotevogel, S.; Alvarez Figueroa, P.A. & Valarezo, C. (2020): Total organic carbon concentrations in ecosystem solutions of a remote tropical montane forest respond to global environmental change. Global Change Biology 26, 6989–7005.
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DOI: 10.1111/gcb.15351
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Abstract:
Abstract:
The response of organic carbon (C) concentrations in ecosystem solutions to environmental change affects the release of dissolved organic matter (DOM) from forests to surface and groundwaters. We determined the total organic C (TOC) concentrations (filtered <1–7 μm) and the ratios of TOC/dissolved organic nitrogen (DON) concentrations, electrical conductivity (EC), and pH in all major ecosystem solutions of a tropical montane forest from 1998 to 2013. The forest was located on the rim of the Amazon basin in Ecuador and experienced increasing numbers of days with >25°C, decreasing soil moisture, and rising nitrogen (N) deposition from the atmosphere during the study period. In rainfall, throughfall, mineral soil solutions (at the 0.15- and 0.30-m depths), and streamflow, TOC concentrations and fluxes decreased significantly from 1998 to 2013, while they increased in stemflow. TOC/DON
ratios decreased significantly in rainfall, throughfall, soil solution at the 0.15-m depth, and streamflow. Based on Δ14C values, the TOC in rainfall and mineral soil solutions was 1 year old and that of litter leachate was 10 years old. The pH in litter leachate decreased with time, that in mineral soil solutions increased, while those in the other ecosystem solutions did not change. Thus, reduced TOC solubility because of lower pH values cannot explain the negative trends in TOC concentrations in most ecosystem
solutions. The increasing TOC concentrations and EC in stemflow pointed at an increased leaching of TOC and other ions from the bark. Our results suggest an accelerated degradation of DOM, particularly of young DOM, associated with the production of N-rich compounds simultaneously to changing climatic conditions and increasing N availability. Thus, environmental change increased the CO2 release to the atmosphere but reduced DOM export to surface and groundwater.
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Keywords: |
Dissolved organic carbon |
time series |
carbon-14 dating |
TOC:DON ratio |
ecosystem fluxes |
Carrillo-Rojas, G.; Schulz, H.M.; Orellana-Alvear, J.; Ochoa-Sánchez, A.; Trachte, K.; Celleri, R. & Bendix, J. (2020): Atmosphere-surface fluxes modeling for the high Andes: The case of páramo catchments of Ecuador. Science of The Total Environment 704, 135372.
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DOI: 10.1016/j.scitotenv.2019.135372
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Abstract:
Abstract:
Interest in atmosphere-surface flux modeling over the mountainous regions of the globe has increased recently, with a major focus on the prediction of water, carbon and other functional indicators in natural and disturbed conditions. However, less research has been centered on exploring energy fluxes (net radiation; sensible, latent and soil heat) and actual evapotranspiration (ETa) over the Neotropical Andean biome of the páramo. The present study assesses the implementation and parameterization of a state-of-art Land-Surface Model (LSM) for simulation of these fluxes over two representative páramo catchments of southern Ecuador. We evaluated the outputs of the LSM Community Land Model (CLM ver. 4.0) with (i) ground-level flux observations from the first (and highest) Eddy Covariance (EC) tower of the Northern Andean páramos; (ii) spatial ETa estimates from the energy balance-based model METRIC (based on Landsat imagery); and (iii) derived ETa from the closure of the water balance (WB). CLM’s energy predictions revealed a significant underestimation on net radiation, which impacts the sensible and soil heat fluxes (underestimation), and delivers a slight overestimation on latent heat flux. Modeled CLM ETa showed acceptable goodness-of-fit (Pearson R = 0.82) comparable to ETa from METRIC (R = 0.83). Contrarily, a poor performance of ETa WB was observed (R = 0.46). These findings provide solid evidence on the CLM’s accuracy for the ETa modeling, and give insights in the selection of other ETa methods. The study contributes to a better understanding of ecosystem functioning in terms of water loss through evaporative processes, and might help in the development of future LSMs’ implementations focused on climate / land use change scenarios for the páramo.
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Keywords: |
Páramo |
CLM |
Evapotranspiration |
METRIC |
Tropical Andes |
Eddy covariance |
Dehling, D.; peralta, G.; Bender, I.M.; Blendinger, P.; Boehning-Gaese, K.; Munoz, M.; Neuschulz, E.; Quitian, M.; Saavedra, F.; Santillan, V.; Schleuning, M. & stouffer, D. (2020): Similar composition of functional roles in Andean seed‐dispersal networks, despite high species and interaction turnover. Ecology 101(7), e03028.
Donoso, I.; Sorensen, M.; Blendinger, P.; Kissling, W.; Neuschulz, E.; Mueller, T. & Schleuning, M. (2020): Downsizing of animal communities triggers stronger functional than structural decay in seed-dispersal networks. Nature Communications 11, 1582.
Sorensen, M.C.; Donoso, I.; Neuschulz, E.; Schleuning, M. & Mueller, T. (2020): Community-wide seed dispersal distances peak at low levels of specialisation in size-structured networks. Oikos 129(11), 1727-1738.
Knoke, T.; Gosling, E. & Paul, C. (2020): Use and misuse of the net present value in environmental studies. Ecological Economics 174(106664), 1-15.
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DOI: 10.1016/j.ecolecon.2020.106664
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Abstract:
Abstract:
Environmental studies regularly use the net present value (NPV) to value benefits and costs of projects. However, the NPV disregards whether the stream of net benefits is steady or volatile and ignores the distribution of net benefits among different groups of people. Here we test alternatives to NPV, building on two example cases: 1) We use discounted utility (DU) to evaluate land-use projects and calculate opportunity costs for avoided deforesta-tion. 2) We simulate decision-making on tropical deforestation, whereby we use multiple decision criteria to consider the distribution of net benefits between two groups: farmers and conservationists. Results show considerable differences in the ranking of projects between DU and NPV, when projects are not marginal. Compared to DU, NPV regularly overestimates the value of forest plantations. Moreover, NPV tends to overstate the opportunity costs of avoiding deforestation in terms of saved carbon emissions. Not accounting for the distribution of net benefits in optimizing land-use allocation leads to suboptimal simulated deforestation scenarios. We therefore suggest that future studies should either also use DU to value economic consequences of projects or that they use the NPV as only one among several socio-economic and ecological decision criteria.
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Keywords: |
land allocation |
Net present value |
Discounted utility |
Euclidian distance |
Uncertainty |
Ochoa Moreno, S.; Härtl, F.; Paul, C. & Knoke, T. (2019): Cropping systems are homogenized by off-farm income – Empirical evidence from small-scale farming systems in dry forests of southern Ecuador. Land Use Policy 82, 204-219.
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DOI: 10.1016/j.landusepol.2018.11.025
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Abstract:
Abstract:
Diversified agricultural landscapes have been shown to provide a wide range of ecosystem services. It is often stated that the main motivation behind growing multiple crops within a farm is to buffer farm income against market and climate risks. However, household characteristics, particularly the amount of off-farm income may also influence farm diversity. While the drivers of diversifying farm income have been investigated extensively,the ecologically important level of land-use diversity on a farm has seldom been used as a dependent variable.
Based on data from 163 households, this paper analyzes the impact of social, economic and demographic household characteristics on crop diversification for farms located around the Laipuna Reserve in the dry forests of southern Ecuador. Using a Heckman two-step regression model, we identified factors that influence a) the probability that a farm will be diversified (PD) and b) the degree of diversification at the farm level (LUD), quantified by the Shannon index. We found that PD is positively related to the percentage of household members who depend on family income but do not work (economic dependence ratio), as well as river access and available family labor force. PD is inversely related to access to financial support (i.e. social payments and credits) and off-farm income. LUD is positively related to the number of household members and the age of the head of the household, and correlates negatively with labor force, financial support and off-farm income. Our results demonstrate that land-use diversification is not only a strategy to reduce risk, but it is also driven by farmers’ efforts to meet household, mainly subsistence, needs. Moreover, we also demonstrate that when households have access to financial support and off-farm income, the pressure to diversify their crops diminishes. Finally, we argue that forest and agricultural policies should impose instruments to support land-use diversification financially, while acknowledging the importance of financial support and off-farm income for household
economies. Strategies to reduce poverty should be accompanied by direct support of land-use diversification, infrastructure development and agricultural training.
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Keywords: |
land use |
land diversification |
Cropping |
Graefe, S.; Rodrigo, R.; Cueva, E.; Butz, P.; Werner, F.A. & Homeier, J. (2020): Impact of disturbance on forest structure and tree species composition in a tropical dry forest of South Ecuador. Ecotropica 22, 202002.
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DOI: 10.30427/ecotrop202002
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Abstract:
Abstract:
Tropical dry forests (TDFs) are often degraded and fragmented through human impact, which is also the case in Southern Ecuador, where land-use pressure is high. In this context we studied tree species composition and forest structure in a protected and adjacent disturbed TDF at altitudes between 560-1080 m asl. Fabaceae and Malvaceae were identified as the most important tree families in both forest types. The disturbed forest displayed lower tree species richness than the protected forest, and the gap in species richness between the two forest types increased with increasing altitude. Ten species of the protected forest were not recorded in the disturbed forest, two of them endemic. The disturbed site was further characterized by a lower number of stems but with larger diameters, in comparison with the protected forest. The majority of the most abundant tree species in the disturbed forest had rather low wood densities, but also the combination of high wood density with browsing tolerance and high resprouting capacity was encountered, and seems to be advantageous for getting established in such sites. Although certain tree species were well represented in the disturbed forest, some endemic species with relatively low abundances (e.g. Simira ecuadorensis, Prockia crucis) should receive more conservation attention.
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Keywords: |
species richness |
altitude |
importance value index |
Tumbesian dry forest |
wood density |
Palomeque, X.; Patiño Uyaguari, C.; Marin, F.; Palacios, M. & Stimm, B. (2020): Effects of storage on seed germination and viability for three native tree species of Ecuador. Trees online, 1-11.
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DOI: 10.1007/s00468-020-02018-2
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Abstract:
Abstract:
Many forests restoration programs and efforts depend on seeds. Particularly in the Andes, further information regarding seed germination requirements and seed storage behavior is necessary. The aim of this study was to evaluate the effects of storage conditions on the germination percentage, the viability and the coefficient of velocity of germination for seeds of three native tree species (Cedrela montana, Weinmannia fagaroides and Oreocallis grandiflora). Under controlled conditions, the seeds were exposed to three levels of seed moisture content and storage temperatures (5 °C, 10 °C and room temperature at approx. 19 °C) for 3, 6 and 12 months. The results showed that at 3–6 months of seed storage under temperatures of 5 and 10 °C, the seeds had a high percentage of germination, viability and germination speed for C. montana and W. fagaroides compared to those stored at room temperature. At 12 months of storage, there was a marked reduction in seed germination in all treatments for both species. Furthermore, the seed germination and viability of O. grandiflora was not influenced by any of the above storage treatments. However, at the end of the experiment a slight decrease was observed, hence this species might be tolerant to medium- and long-term storage conditions. Though limited to just three co-occurring species, the study provided insight into the variability in responses to storage, with preliminary indications of appropriate storage conditions to maximize storability of seeds for restoration programs. Importantly, the study demonstrated the need for empirical testing of storage responses (temperature and duration) of seeds before subjecting untested species to a particular storage regime.
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Keywords: |
Seed storage behavior |
Reforestation |
ex situ conservation |
seed management |
Cueva Ortiz, J.L.; Espinosa, C.I.; Aguirre-Mendoza, Z.; Gusmán-Montalván, E.; Weber, M. & Hildebrandt, P. (2020): Natural Regeneration in the Tumbesian Dry Forest: Identification of the Drivers Affecting Abundance and Diversity. Scientific Reports 10( 9786), 13.
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DOI: 10.1038/s41598-020-66743-x
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Abstract:
Abstract:
Tropical and subtropical dry forests make up the world’s largest terrestrial ecosystem. However, these forests have been used to establish several productive activities, such as growing crops, rearing livestock, and using the forest resources, due to their ease of access and climatic conditions, which has led to this ecosystem becoming highly threatened. Therefore, this research assessed the effects of anthropogenic pressures and a number of abiotic variables on natural regeneration in dry forests in the Tumbesian region by addressing three research questions: (a) What is the status of natural regeneration in terms of abundance and diversity? (b) Does livestock grazing and the anthropogenic pressure affect the abundance and diversity of natural regeneration? (c) Does seasonality or grazing have the greatest influence on the regeneration dynamics? Data were obtained from 72 samples (36 fenced and 36 unfenced) during five surveys spanning a 2-year period, and the seedling abundance, mortality, recruitment, species richness and diversity were evaluated using linear mixed models. Natural regeneration was most positively affected by rainy season precipitation, but soil conditions also played an important role. Short-term fences had a major effect on reducing mortality but did not improve the abundance or diversity, whereas cattle grazing significantly affected the abundance of seedlings.
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Keywords: |
grazing |
natural forest regeneration |
anthropogenic pressure |