Remote sensing analytical geospatial operations directly in the web browser

Masó J., Zabala A., Serral I., Pons X. (2018) Remote sensing analytical geospatial operations directly in the web browser. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives. 42: 475-482.
Link
Doi: 10.5194/isprs-archives-XLII-4-403-2018

Abstract:

Current map viewers that run on modern web browsers are mainly requesting images generated on the fly in the server side and transferred in pictorial format that they can display (PNG or JPEG). In OGC WMS standard this is done for the whole map view while in WMTS is done per tiles. The user cannot fine tune personalized visualization or data analysis in the client side. Remote sensing data is structured in bands that are visualize individually (manually adjusting contrast), create RGB combinations or present spectral indices. When these operations are not available in map browsers professional are forced to download hundreds of gigabytes of remote sensing imagery to take a good look at the data before deciding if it fits for a purpose. A possible solution is to create a web service that is able to perform these operations on the server side (https://www.sentinel-hub.com). This paper proposes that the server should communicate the data values to the client in a format that the client can directly process using two new additions in HTML5: canvas edition and array buffers. In the client side, the user can interact with a JavaScript interface changing symbolizations and doing some analytical operations without having to request any data again to the server. As a bonus, the user is able to perform queries to the data in a more dynamic way, applying spatial filters, creating histograms, generating animations of a time series or performing complex calculations among bands of the different loaded datasets. © Authors 2018.

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Drivers and mechanisms of tree mortality in moist tropical forests

Mcdowell N., Allen C.D., Anderson-Teixeira K., Brando P., Brienen R., Chambers J., Christoffersen B., Davies S., Doughty C., Duque A., Espirito-Santo F., Fisher R., Fontes C.G., Galbraith D., Goodsman D., Grossiord C., Hartmann H., Holm J., Johnson D.J., Kassim A.R., Keller M., Koven C., Kueppers L., Kumagai T., Malhi Y., Mcmahon S.M., Mencuccini M., Meir P., Moorcroft P., Muller-Landau H.C., Phillips O.L., Powell T., Sierra C.A., Sperry J., Warren J., Xu C., Xu X. (2018) Drivers and mechanisms of tree mortality in moist tropical forests. New Phytologist. : 0-0.
Link
Doi: 10.1111/nph.15027

Abstract:

Tree mortality rates appear to be increasing in moist tropical forests (MTFs) with significant carbon cycle consequences. Here, we review the state of knowledge regarding MTF tree mortality, create a conceptual framework with testable hypotheses regarding the drivers, mechanisms and interactions that may underlie increasing MTF mortality rates, and identify the next steps for improved understanding and reduced prediction. Increasing mortality rates are associated with rising temperature and vapor pressure deficit, liana abundance, drought, wind events, fire and, possibly, CO2 fertilization-induced increases in stand thinning or acceleration of trees reaching larger, more vulnerable heights. The majority of these mortality drivers may kill trees in part through carbon starvation and hydraulic failure. The relative importance of each driver is unknown. High species diversity may buffer MTFs against large-scale mortality events, but recent and expected trends in mortality drivers give reason for concern regarding increasing mortality within MTFs. Models of tropical tree mortality are advancing the representation of hydraulics, carbon and demography, but require more empirical knowledge regarding the most common drivers and their subsequent mechanisms. We outline critical datasets and model developments required to test hypotheses regarding the underlying causes of increasing MTF mortality rates, and improve prediction of future mortality under climate change. © 2018 New Phytologist Trust.

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Short-term effects of drought on tropical forest do not fully predict impacts of repeated or long-term drought: Gas exchange versus growth

Meir P., Mencuccini M., Binks O., Da Costa A.L., Ferreira L., Rowland L. (2018) Short-term effects of drought on tropical forest do not fully predict impacts of repeated or long-term drought: Gas exchange versus growth. Philosophical Transactions of the Royal Society B: Biological Sciences. 373: 0-0.
Link
Doi: 10.1098/rstb.2017.0311

Abstract:

Are short-term responses by tropical rainforest to drought (e.g. during El Niño) sufficient to predict changes over the long-term, or from repeated drought? Using the world’s only long-term (16-year) drought experiment in tropical forest we examine predictability from short-term measurements (1 – 2 years). Transpiration was maximized in droughted forest: it consumed all available throughfall throughout the 16 years of study. Leaf photosynthetic capacity ðVcmax Þ was maintained, but only when averaged across tree size groups. Annual transpiration in droughted forest was less than in control, with initial reductions (at high biomass) imposed by foliar stomatal control. Tree mortality increased after year three, leading to an overall biomass loss of 40%; over the long-term, the main constraint on transpiration was thus imposed by the associated reduction in sapwood area. Altered tree mortality risk may prove predictable from soil and plant hydraulics, but additional monitoring is needed to test whether future biomass will stabilize or collapse. Allocation of assimilate differed over time: stem growth and reproductive output declined in the short-term, but following mortality-related changes in resource availability, both showed long-term resilience, with partial or full recovery. Understanding and simulation of these phenomena and related trade-offs in allocation will advance more effectively through greater use of optimization and probabilistic modelling approaches. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’. © 2018 The Authors.

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Ecological traps for large-scale invasive species control: Predicting settling rules by recolonising American mink post-culling

Melero Y., Cornulier T., Oliver M.K., Lambin X. (2018) Ecological traps for large-scale invasive species control: Predicting settling rules by recolonising American mink post-culling. Journal of Applied Ecology. 55: 1769-1779.
Link
Doi: 10.1111/1365-2664.13115

Abstract:

Management programmes seeking to reduce the density of invasive species must overcome compensatory processes, such as recolonisation by dispersers from non- or partially controlled areas. However, the scale and drivers of dispersal in such contexts are poorly known. We investigated the dispersal patterns of American mink re-invading 20,000 km2 of their non-native range during a culling programme led by citizen conservationists. Using multinomial models, we estimated the contributions of density dependence, proxies for patch quality and distance from the natal patch on mink settlement. Seventy-seven per cent of mink dispersed and settled in non-natal patches. Dispersal distances were large with settlement probabilities only reduced by half at c. 60 km, and 20% of mink dispersing >80 km. Females were more attracted to high-quality patches, mostly found at low altitudes. Males favoured patches with intermediate current densities and consistently high quality. Synthesis and applications. We predicted post-culling recolonisation by a non-native mobile carnivore over a large spatial scale by using information on relative densities obtained during management interventions, largely carried out by citizen conservationists. This was possible through continued monitoring of the area designed to feed into the adaptive management process of the control project. High mink mobility dictates management should take place on very large spatial scales to minimise re-invasion from uncontrolled areas. Our research shows both males and females are attracted to patches with previously consistent occupation, which provides a degree of predictability to patterns of recolonisation. Targeting control to patches that are attractive to immigrant mink requires knowledge of current mink density. Creating so-called ecological traps in the face of ongoing immigration from peripheral areas provides a promising tool to effectively control mobile invasive species. © 2018 The Authors. Journal of Applied Ecology © 2018 British Ecological Society

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Influence of clay licks on the diversity and structure of an Amazonian forest

Molina E., Espelta J.M., Pino J., Bagaria G., Armenteras D. (2018) Influence of clay licks on the diversity and structure of an Amazonian forest. Biotropica. 50: 740-749.
Link
Doi: 10.1111/btp.12568

Abstract:

The spatial heterogeneity of resource availability is a major driver of biodiversity patterns. Some environmental conditions and resources are characterized by large-scale patterns of variation within the landscape. Clumped local discontinuities or discrete elements also increase spatial heterogeneity, promoting local ‘biodiversity hot spots’ by modifying habitat characteristics and promoting plant–animal interactions. Clay licks are faunal attractors owing to their role in the nutritional ecology of the user species; nevertheless, the effect of their presence on the surrounding vegetation has been poorly quantified. Here, we use data from 100 × 10 m transects and evaluate the effects of the presence of clay licks on forest diversity and structure at local and landscape scales. In clay lick areas, there was a higher abundance of certain species, which helps to homogenize species composition between localities counteracting the natural distance-decay of compositional similarity between transects without clay lick influence (controls). Compared to control sites, clay lick′s forests had higher palm densities, shorter but more variable individuals in the canopy and understory, a thinner canopy layer, and denser herbaceous and ground level covers. These differences were found along the whole length of transects in both sampled areas types. These results reveal that the presence of discrete elements (i.e., clay licks) may help to explain the compositional and structural heterogeneity of Amazonian forests influencing ecological processes such as seed dispersal and trampling. These considerations may be relevant for other biomes where clay licks are present and give weight to their inclusion in conservation initiatives in tropical forests. © 2018 The Association for Tropical Biology and Conservation

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Severe wildfire in a mediterranean forest

Molowny-Horas R., Borrego A., Riera P., Espelta J.M. (2018) Severe wildfire in a mediterranean forest. Equivalency Methods for Environmental Liability: Assessing Damage and Compensation Under the European Environmental Liability Directive. : 203-234.
Link
Doi: 10.1007/978-90-481-9812-2_11

Abstract:

This case study illustrates the equivalency analysis for estimating ex post environmental damage and appropriate compensatory remediation following a severe wildfire caused by a power line in a forest protected under the European Union Habitats Directive (HD). The study addresses long-term environmental damage (e.g., over several decades) by a large-scale disturbance in a terrestrial ecosystem, and includes an analysis of uncertainty associated with the potential occurrence of natural future fire events in the area. Accounting for the probability of natural future forest fires directly affects both baseline and compensatory remediation options by reducing the habitat area compared to an assumption of no future forest fires. Only natural forest fires, i.e., 10% of all forest fires, have been included in the calculations of both the baseline and the compensatory remediation, since the operator may not be made liable for accidental or provoked forest fires. The impact of this hypothesis is tested by means of a sensitivity analysis. The case study illustrates: • Considerations in selecting a metric from various potential ones (hectares, trees, biomass, habitat quality) for terrestrial habitats included in the HD; • Application of a value equivalency approach (specifically, value-to-value); • Analysis of key variables (e.g., differences in metrics, single/multiple metrics, on-site/off-site implementation); and • Sensitivity of the results to changes in four key model parameters (i.e. area of future forest fires, tree mortality, percentage of natural forest fires and tree minimum diameter at breast height). © Springer Science+Business Media B.V. 2018.

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Araneus bonali sp. N., a novel lichen-patterned species found on oak trunks (Araneae, Araneidae)

Morano E., Bonal R. (2018) Araneus bonali sp. N., a novel lichen-patterned species found on oak trunks (Araneae, Araneidae). ZooKeys. 2018: 119-145.
Link
Doi: 10.3897/zookeys.779.26944

Abstract:

The new species Araneus bonali Morano, sp. n. (Araneae, Araneidae) collected in central and western Spain is described and illustrated. Its novel status is confirmed after a thorough revision of the literature and museum material from the Mediterranean Basin. The taxonomy of Araneus is complicated, but both morphological and molecular data supported the genus membership of Araneus bonali Morano, sp. n. Additionally, the species uniqueness was confirmed by sequencing the barcode gene cytochrome oxidase I from the new species and comparing it with the barcodes available for species of Araneus. A molecular phylogeny, based on nuclear and mitochondrial genes, retrieved a clade with a moderate support that grouped Araneus diadematus Clerck, 1757 with another eleven species, but neither included Araneus bonali sp. n. nor Araneus angulatus Clerck, 1757, although definitive conclusions about the relationships among Araneus species need more markers examined and a broader taxonomic coverage. The new species was collected on isolated holm oaks and forest patches within agricultural landscapes. Adults were mostly trapped on tree trunks, where their lichen-like colours favour mimicry, while juveniles were collected on tree branches. Specimens were never found either in ground traps or grass samples. This species overwinters as egg, juveniles appear in early spring, but reproduction does not take place until late summer-early autumn. Araneus bonali Morano, sp. n. was found in the same locality from where another new spider species was described. Nature management policies should thus preserve isolated trees as key refuges for forest arthropods in agricultural landscapes, as they may be hosting more unnoticed new species. After including Araneus bonali Morano, sp. n. and removing doubtful records and synonymies, the list of Araneus species in the Iberian Peninsula numbers eight. © Eduardo Morano, Raul Bonal.

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A methodology to derive global maps of leaf traits using remote sensing and climate data

Moreno-Martínez Á., Camps-Valls G., Kattge J., Robinson N., Reichstein M., van Bodegom P., Kramer K., Cornelissen J.H.C., Reich P., Bahn M., Niinemets Ü., Peñuelas J., Craine J.M., Cerabolini B.E.L., Minden V., Laughlin D.C., Sack L., Allred B., Baraloto C., Byun C., Soudzilovskaia N.A., Running S.W. (2018) A methodology to derive global maps of leaf traits using remote sensing and climate data. Remote Sensing of Environment. 218: 69-88.
Link
Doi: 10.1016/j.rse.2018.09.006

Abstract:

This paper introduces a modular processing chain to derive global high-resolution maps of leaf traits. In particular, we present global maps at 500 m resolution of specific leaf area, leaf dry matter content, leaf nitrogen and phosphorus content per dry mass, and leaf nitrogen/phosphorus ratio. The processing chain exploits machine learning techniques along with optical remote sensing data (MODIS/Landsat) and climate data for gap filling and up-scaling of in-situ measured leaf traits. The chain first uses random forests regression with surrogates to fill gaps in the database (> 45% of missing entries) and maximizes the global representativeness of the trait dataset. Plant species are then aggregated to Plant Functional Types (PFTs). Next, the spatial abundance of PFTs at MODIS resolution (500 m) is calculated using Landsat data (30 m). Based on these PFT abundances, representative trait values are calculated for MODIS pixels with nearby trait data. Finally, different regression algorithms are applied to globally predict trait estimates from these MODIS pixels using remote sensing and climate data. The methods were compared in terms of precision, robustness and efficiency. The best model (random forests regression) shows good precision (normalized RMSE≤ 20%) and goodness of fit (averaged Pearson's correlation R = 0.78) in any considered trait. Along with the estimated global maps of leaf traits, we provide associated uncertainty estimates derived from the regression models. The process chain is modular, and can easily accommodate new traits, data streams (traits databases and remote sensing data), and methods. The machine learning techniques applied allow attribution of information gain to data input and thus provide the opportunity to understand trait-environment relationships at the plant and ecosystem scales. The new data products – the gap-filled trait matrix, a global map of PFT abundance per MODIS gridcells and the high-resolution global leaf trait maps – are complementary to existing large-scale observations of the land surface and we therefore anticipate substantial contributions to advances in quantifying, understanding and prediction of the Earth system. © 2018 Elsevier Inc.

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Long-term response of forest productivity to climate change is mostly driven by change in tree species composition

Morin X., Fahse L., Jactel H., Scherer-Lorenzen M., García-Valdés R., Bugmann H. (2018) Long-term response of forest productivity to climate change is mostly driven by change in tree species composition. Scientific Reports. 8: 0-0.
Link
Doi: 10.1038/s41598-018-23763-y

Abstract:

Climate change affects ecosystem functioning directly through impacts on plant physiology, resulting in changes of global productivity. However, climate change has also an indirect impact on ecosystems, through changes in the composition and diversity of plant communities. The relative importance of these direct and indirect effects has not been evaluated within a same generic approach yet. Here we took advantage of a novel approach for disentangling these two effects in European temperate forests across a large climatic gradient, through a large simulation-based study using a forest succession model. We first showed that if productivity positively correlates with realized tree species richness under a changed climate, indirect effects appear pivotal to understand the magnitude of climate change impacts on forest productivity. We further detailed how warmer and drier conditions may affect the diversity-productivity relationships (DPRs) of temperate forests in the long term, mostly through effects on species recruitment, ultimately enhancing or preventing complementarity in resource use. Furthermore, losing key species reduced the strength of DPRs more severely in environments that are becoming climatically harsher. By disentangling direct and indirect effects of climate change on ecosystem functioning, these findings explain why high-diversity forests are expected to be more resilient to climate change. © 2018 The Author(s).

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Efficiency of species survey networks can be improved by integrating different monitoring approaches in a spatial prioritization design

Morán-Ordóñez A., Canessa S., Bota G., Brotons L., Herrando S., Hermoso V. (2018) Efficiency of species survey networks can be improved by integrating different monitoring approaches in a spatial prioritization design. Conservation Letters. 11: 0-0.
Link
Doi: 10.1111/conl.12591

Abstract:

Public participation to monitoring programs is increasingly advocated to overcome scarcity of resources and deliver important information for policy-making. Here, we illustrate the design of optimal monitoring networks for bird species of conservation concern in Catalonia (NE Spain), under different scenarios of combined governmental and citizen-science monitoring approaches. In our case study, current government efforts, limited to protected areas, were insufficient to cover the whole spectrum of target species and species-threat levels, reinforcing the assumption that citizen-science data can greatly assist in achieving monitoring targets. However, simply carrying out both government and citizen-science monitoring ad hoc led to inefficiency and duplication of efforts: some species were represented in excess of targets while several features were undersampled. Policy-making should concentrate on providing an adequate platform for coordination of government and public-participatory monitoring to minimize duplicated efforts, overcome the biases of each monitoring program and obtain the best from both. © 2018 The Authors. Conservation Letters published by Wiley Periodicals, Inc.

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