Análisis y modelización de datos espacialmente explícitos en ecología

Este artículo ha sido elaborado gracias a un contrato Ramón y Cajal del Ministerio de Educación y Ciencia en el marco de los proyectos CEFEMED (URJC-RNT-063-2), REMEDINAL (S-0505/AMB/0335) y SPABIOCRUST (ECPG 231/607), financiados por la Comunidad de Madrid (CM), la CM y la Universidad Rey Juan Carlos y la British Ecological Society, respectivamente

El coste ambiental de la agricultura intensiva en las zonas áridas de nuestro planeta

Seminario organizado por el Grupo de Investigación de Alimentación y Nutrición (ALINUT), Departamento de Enfermería Comunitaria, Medicina Preventiva y Salud Pública e Historia de la Ciencia, Universidad de Alicante. Coordinación del evento: Prof. Dra. Rocío Ortiz Moncada. Lugar: Salón de Grados de la Facultad de Ciencias de la Salud, Universidad de Alicante (España)

II Reunión del grupo de trabajo de ecología espacial de la AEET

Reseña de la II Reuinión del grupo de trabajo de ecología espacial de la Asociación Española de Ecología Terrestr

Life adapted to precariousness: The ecology of drylands

Drylands occupy approximately 40 % of the Earth's surface. Their peculiar hydrological regime, with water as the main limiting factor, together with other characteristics, such as the variability of rainfall and their ecological heterogeneity, turn these regions into one of the main and most relevant sets of biomes on the planet. Beyond their stereotypical conception as places with a low economic and ecological profile, these territories have enormous biodiversity and support 40 % of the world's population. Global warming is increasing atmospheric aridity and the strategies developed over millennia by their inhabitants are a model to learn from. Preserving these places is essential to combat climate change, and to do so, it is essential to have an in-depth understanding of their structure and functioning.This work was funded by the European Research Council (Grant Agreement Nº 647038, BIODESERT) and the Valencian Regional Government (CIDEGENT/2018/041). Emilio Guirado receives funding from the Regional Department of Education, Culture, and Sport of the Valencian Regional Government and the European Social Fund [project APOSTD/2021/188]

Randomization tests for quantifying species importance to ecosystem function

1. Quantifying the contribution of different species to ecosystem function is an important challenge. We introduce simple randomization tests (and software) for quantifying the average effect of species on ecosystem variables measured in multiple plots with and without the presence of a particular species. These randomization tests formalize the analysis of uncontrolled \u27natural experiments\u27 and quantify species effects in standardized deviation units. 2.We tested the method with data on ecosystem function in biological soil crust assemblages of lichens in semi-arid gypsum outcrops in central Spain. In sixty-three 50cm×50cm sample plots, we measured the presence and percentage cover of 17 species of lichens and the levels of five important ecosystem variables (organic carbon, total nitrogen, urease activity, phosphatase activity and β-glucosidase activity). The randomization tests revealed 13 positive and six negative associations between species presence and ecosystem function. 3.We used data from an independent microcosm experiment on ecosystem function and species composition to validate these results. Microcosms that had higher levels of organic carbon and total nitrogen also had higher average species effect scores (measured from the survey data) for the species that were present in each experimental treatment. 4.As in all natural experiments, strong species interactions, effects of unmeasured abiotic variables on species occurrence and reciprocal effects of ecosystem variables on species occurrence can potentially confound estimates of species importance. Nevertheless, the method we propose provides a simple index and statistical test of species importance that can form the basis for additional hypothesis tests and experimental studies of species occurrence and ecosystem function. © 2011 The Authors. Methods in Ecology and Evolution © 2011 British Ecological Society

Desertifying deserts

The current definition of desertification excludes hyper-arid zones given their lack of economic activity. However, the 101 million people living there, ongoing land degradation associated with the use of groundwater for intensive agriculture and climate-change-induced aridity call for a revision of this definition.This work was funded by the European Research Council grant agreement no. 647038 (BIODESERT). F.T.M. acknowledges support from Generalitat Valenciana (CIDEGENT/2018/041)

Unraveling Misunderstandings about Desertification: The Paradoxical Case of the Tabernas-Sorbas Basin in Southeast Spain

From its origins, the concept of desertification has been controversial. The prevailing confusion between two desertification visions, one that considers it as the expansion of deserts and another that emphasizes its anthropogenic component, has been transferred to society. Here we illustrate misunderstandings about desertification using a very illustrative case from the Tabernas-Sorbas Basin (Almeria, Spain), where striking badlands that are often used as an image of desertification coexist with an intensive olive agriculture that is irreversibly deteriorating the only oasis in continental Europe (Los Molinos spring). The olive tree is a traditional Mediterranean dryland crop and until the 1950s only about 200 ha were irrigated in this area. However, the profitability of the crop has caused irrigation to expand to 4400 ha in the last two decades. The process of intensification has been reinforced giving way to super-intensive irrigation, which involves going from 210 to 1550 trees/ha, which in a few years already occupies more than 1500 ha. The effects on the water balance of the aquifer feeding these crops have been severe, and the flow of the Los Molinos spring has gone from more than 40 L/s for the period 1970–2000 to the current 7.28 L/s. Unraveling the mechanisms of land degradation and its main drivers are the first step to propose management actions to achieve a more sustainable use of resources and to combat desertification.This research was funded by the European Research Council grant agreement nº 647038 (BIODESERT). FTM acknowledges support from Generalitat Valenciana (CIDEGENT/2018/041)

Null model tests for niche conservatism, phylogenetic assortment and habitat filtering

Phylogenetic and trait analyses are powerful tools for disentangling the mechanisms underlying the structure of plant and animal communities, and their use has become prominent in the last decade. However, few studies have simultaneously incorporated data on species traits or phylogeny, environment, and species co-occurrences. Therefore, the relative importance of these factors as drivers of community assembly is largely unknown. 2.We introduce new and conceptually simple null model tests and appropriate metrics to disentangle the relationships between species co-occurrence, traits or phylogeny and environmental factors not covered by available packages for phylogenetic analysis. We illustrate the methods with an extensive data set on understory plant assemblages sampled in three Polish forests. 3.Benchmark testing indicates that the proposed methods have good error behaviour when tested against a variety of artificial matrix sets covering a wide range of observed patterns. Test results are largely independent of matrix size and matrix fill and have adequate power to detect even weak patterns of non-randomness. The different metrics used are uncorrelated with one another and capture different, and often divergent, patterns expressed within the same matrix. Our case study revealed three distinct patterns in forest understory plant assemblages: (i) multiple patterns of species associations within meta-communities might mask the influence of phylogeny and environmental variables on species occurrences, (ii) the strength of environmental and phylogenetic signals depend on the co-occurrence pattern (segregated, aggregated, clumped) and might vary within a single meta-community, and (iii) a random association of phylogeny and species co-occurrence coupled with significant correlations between environmental factors and phylogeny might reveal species with traits that have passed through environmental filtering. © 2012 The Authors. Methods in Ecology and Evolution © 2012 British Ecological Society