Applying the eco-hydrological equilibrium hypothesis to model root distribution in water-limited forests

Cabon A., Martínez-Vilalta J., Martínez de Aragón J., Poyatos R., De Cáceres M. (2018) Applying the eco-hydrological equilibrium hypothesis to model root distribution in water-limited forests. Ecohydrology. : 0-0.
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Doi: 10.1002/eco.2015

Resum:

Drought is a key driver of vegetation dynamics, but plant water-uptake patterns and consequent plant responses to drought are poorly understood at large spatial scales. The capacity of vegetation to use soil water depends on its root distribution (RD). However, RD is extremely variable in space and difficult to measure in the field, which hinders accurate predictions of water fluxes and vegetation dynamics. We propose a new method to estimate RD within water balance models, assuming that vegetation is at eco-hydrological equilibrium (EHE). EHE conditions imply that vegetation optimizes RD such that transpiration is maximized within the limits of bearable drought stress, characterized here by species-specific hydraulic thresholds. Optimized RD estimates were validated against RD estimates obtained by model calibration from sap flow or soil moisture from 38 forest plots in Catalonia (NE Spain). In water-limited plots, optimized RD was similar to calibrated RD, but estimates diverged with higher water availability, suggesting that the EHE may not be assumed when water is not limiting. Thereafter, we applied the optimization procedure at the regional scale, to estimate RD for the water-limited forests of Catalonia. Regional variations of optimum RD reproduced many expected patterns in response to climate, soil physical properties, forest structure, and species hydraulic traits. We conclude that RD optimization, based on the EHE hypothesis and a simple description of plant hydraulics, produces realistic estimates of RD that can be used for model parameterization and shows promise to improve our ability to forecast vegetation dynamics under increased drought. © 2018 John Wiley & Sons, Ltd.

Llegeix més

Sobre el intercambio de datos de vegetación: El estándar ‘Veg-X’ y el paquete de R ‘VegX’

De Cáceres M. (2018) Sobre el intercambio de datos de vegetación: El estándar ‘Veg-X’ y el paquete de R ‘VegX’. Ecosistemas. 27: 128-129.
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Doi: 10.7818/ECOS.1570

Resum:

[No abstract available]

Llegeix més

Global overview of plot-based vegetation classification approaches

De Cáceres M., Franklin S.B., Hunter J.T., Landucci F., Dengler J., Roberts D.W. (2018) Global overview of plot-based vegetation classification approaches. Phytocoenologia. 48: 101-112.
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Doi: 10.1127/phyto/2018/0256

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While classification of vegetation can be conducted in many ways, international homogenization of procedures and typologies is desirable for human societies that are highly connected in terms of sharing biodiversity information. This Special Issue of Phytocoenologia includes 12 papers that document several of the plot-based classification approaches currently used throughout the world. The issue includes approaches from five continents, but noticeable gaps are South America, middle-eastern countries, northern Africa and southeastern Asia. We include in this editorial a brief synthesis of the papers included in the Special Issue, with respect to (1) the amount of vegetation-plot data and characteristics of the classification systems developed in different areas and (2) the concepts and procedures of classification approaches. One of the most important common attributes among the classification approaches is the need to define vegetation units at a low level of abstraction. 'Association' (and perhaps 'alliance' too) may be a classification level for which international homogenization of procedures would be most easy to achieve, perhaps establishing different consistent classification sections depending on ecological conditions. Several papers in this issue demonstrate that multiple approaches may coexist for higher levels, as long as they abstract vegetation from the same low level units by focusing on a specific set of concepts and defined from the perspective of applications. © 2017 Gebrüder Borntraeger, 70176 Stuttgart, Germany.

Llegeix més

Estimating daily meteorological data and downscaling climate models over landscapes

De Cáceres M., Martin-StPaul N., Turco M., Cabon A., Granda V. (2018) Estimating daily meteorological data and downscaling climate models over landscapes. Environmental Modelling and Software. 108: 186-196.
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Doi: 10.1016/j.envsoft.2018.08.003

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High-resolution meteorological data are necessary to understand and predict climate-driven impacts on the structure and function of terrestrial ecosystems. However, the spatial resolution of climate reanalysis data and climate model outputs is often too coarse for studies at local/landscape scales. Additionally, climate model projections usually contain important biases, requiring the application of statistical corrections. Here we present ‘meteoland’ an R package that integrates several tools to facilitate the estimation of daily weather over landscapes, both under current and future conditions. The package contains functions: (1) to interpolate daily weather including topographic effects; and (2) to correct the biases of a given weather series (e.g., climate model outputs). We illustrate and validate the functions of the package using weather station data from Catalonia (NE Spain), re-analysis data and climate model outputs for a specific county. We conclude with a discussion of current limitations and potential improvements of the package. © 2018

Llegeix més

Effect of climatic and soil moisture conditions on mushroom productivity and related ecosystem services in Mediterranean pine stands facing climate change

Karavani, A., De Cáceres, M., Martínez de Aragón, J., Bonet, J.A., de-Miguel, S. (2018) Effect of climatic and soil moisture conditions on mushroom productivity and related ecosystem services in Mediterranean pine stands facing climate change. Agricultural and Forest Meteorology. 248: 432-440.
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Doi: 10.1016/j.agrformet.2017.10.024

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Assessing the distribution of forest ecosystem services in a highly populated Mediterranean region

Roces-Díaz J.V., Vayreda J., Banqué-Casanovas M., Cusó M., Anton M., Bonet J.A., Brotons L., De Cáceres M., Herrando S., Martínez de Aragón J., de-Miguel S., Martínez-Vilalta J. (2018) Assessing the distribution of forest ecosystem services in a highly populated Mediterranean region. Ecological Indicators. 93: 986-997.
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Doi: 10.1016/j.ecolind.2018.05.076

Resum:

Forest ecosystems provide a wide range of goods and services to society and host high levels of biodiversity. Nevertheless, forest ecosystem services (ES) are often quantified and assessed using simplified methodologies (e.g., proxy methods based exclusively on Land Use Land Cover maps) that introduce substantial uncertainty in the analysis by ignoring, for instance, the species composition and spatial configuration of the ecosystems studied. In this work we defined and calculated a set of 12 indicators of several ES for the forests of the highly populated region of Catalonia (North-eastern Iberian Peninsula). The indicators combined different sources of information such as forest surveys, ecological model predictions and official statistics, but also included additional land cover information. All ES indicators were aggregated at the municipality level to compare their values and distribution patterns. We assessed spatial trade-offs and synergies among ES, as well as their relationships with a set of socioeconomic, climatic and biodiversity variables using correlation analyses and mixed-effects models. The results suggest a clustering of provisioning and regulating ES in mountainous zones towards the North of the study area. These two types of services showed a high degree of spatial similarity and presented high positive correlations. In contrast, cultural ES showed a more scattered pattern, which included lower elevation areas in the South of the study region. Climatic conditions were the main determinants of the spatial variability in the supply of the different ES, with most indicators being positively associated with precipitation and negatively associated with temperature. In addition, biodiversity (particularly woody species richness) showed positive relations with most of these ES, while socioeconomic variables (such as population density and the percentage employment in agriculture) showed negative associations with most of them. The combination of information from different data sources (including primary data) allowed for a detailed analysis of forest ES, likely removing some of the problems derived from approaches based only on proxy methods. In addition, the use of municipalities as study unit makes results directly relevant to management and planning strategies operating at this scale (e.g., forest management and planning). © 2018 Elsevier Ltd

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