Gallardo, Antonio

Catedrático/a de Universidad
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First Name
Last Name
Universidad Pablo de Olavide
Sistemas Físicos, Químicos y Naturales
Research Center
Research Group
Organismos y Sistemas
Recursos Naturales, Energía y Medio Ambiente
PhD programs
Biodiversidad y Biología de la Conservación
UPO investigaORCIDScopus Author IDWeb of Science ResearcherIDDialnet ID

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Now showing 1 - 4 of 4
  • Publication
    Data from: Quercus suber dieback alters soil respiration and nutrient availability in Mediterranean forests
    (Dryad, 2016-06-14) Avila, José Manuel; Gallardo, Antonio; Ibánez, Beatriz; Gómez-Aparicio, Lorena
    An increase in tree mortality rates has been recently detected in forests world-wide. However, few works have focused on the potential consequences of forest dieback for ecosystem functioning. Here we assessed the effect of Quercus suber dieback on carbon, nitrogen and phosphorus cycles in two types of Mediterranean forests (woodlands and closed forests) affected by the aggressive pathogen Phytophthora cinnamomi. We used a spatially explicit neighbourhood approach to analyse the direct effects of Q. suber dieback on soil variables, comparing the impact of Q. suber trees with different health status, as well as its potential long-term indirect effects, comparing the impact of non-declining coexistent species. Quercus suber dieback translated into lower soil respiration rates and phosphorus availability, whereas its effects on nitrogen varied depending on forest type. Coexistent species differed strongly from Q. suber in their effects on nutrient availability, but not on soil respiration rates. Our models showed low interannual but high intra-annual variation in the ecosystem impacts of tree dieback. Synthesis. Our results support that tree dieback might have important short- and long-term impacts on ecosystem processes in Mediterranean forests. With this work, we provide valuable insights to fill the existent gap in knowledge on the ecosystem-level impacts of forest dieback in general and P. cinnamomi-driven mortality in particular. Because the activity and range of this pathogen is predicted to increase due to climate warming, these impacts could also increase in the near future altering ecosystem functioning world-wide.
  • Publication
    Plant footprint decreases the functional diversity of molecules in topsoil organic matter after millions of years of ecosystem development
    (Wiley Online Library, 2023-11-27) Sáez Sandino, Tadeo; Gallardo, Antonio; J. Eldridge, David; Asefaw Berhe, Asmeret; Doetterl, Sebastian; Delgado Baquerizo, Manuel
    Aim: Theory suggests that the diversity of molecules in soil organic matter (SOM functional diversity) provides key insights on multiple ecosystem services. We aimed to investigate how and why SOM functional diversity and composition change as topsoils develop, and its implications for key soil functions (e.g., from nutrient pool to water regulation). Location: We reported data on 16 soil chronosequences globally distributed in nine countries from six continents. Methods: SOM functional diversity and composition without mineral interference were measured using diffuse reflectance mid-infrared Fourier transform spectroscopy (DRIFT). We aimed to characterize the main environmental factors related to SOM functional diversity and composition. Also, we calculated the links among SOM functional diversity and key soil functions. Results: We found that SOM functional diversity declines after millions of years of soil formation (pedogenesis). We further showed that increases in plant cover and productivity led to a higher ratio of reduced (e.g., alkanes) over oxidized carbon forms (i.e., C: O-functional groups ratio), which was positively correlated to SOM functional diversity as soils age. Our findings indicated that the plant footprint (i.e., the accumulation of plant-derived material promoting the C: O-functional group ratio) would explain the reduction of SOM functional diversity as ecosystems develop. Moreover the dissimilarity in SOM composition consistently increased with soil age, with the soil development stage emerging as the main predictor of SOM dissimilarity across contrasting biomes. Main Conclusions: Our global survey contextualized the natural history of SOM functional diversity and composition during long-term soil development. Together, we showed how plant footprint drives the losses of SOM functional diversity with increasing age, which might provide a novel mechanism to explain typically reported losses in ecosystem functions during ecosystem retrogression.
  • Publication
    Biocrusts increase the resistance to warming-induced increases in topsoil P pools
    (Wiley, 2022-05) García Velázquez, Laura; Gallardo, Antonio; Ochoa, Victoria; Lázaro, Roberto; Maestre, Fernando T.
    Ongoing global warming and alterations in rainfall patterns driven by climate change are known to have large impacts on biogeochemical cycles, particularly on drylands. In addition, the global increase in atmospheric nitrogen (N) deposition can destabilize primary productivity in terrestrial ecosystems, and phosphorus (P) may become the most limiting nutrient in many terrestrial ecosystems. However, the impacts of climate change on soil P pools in drylands remain poorly understood. Furthermore, it is unknown whether biocrusts, a major biotic component of drylands worldwide, modulate such impacts. Here we used two long-term (8-10 years) experiments conducted in Central (Aranjuez) and SE (Sorbas) Spain to test how a ~2.5°C warming, a ~30% rainfall reduction and biocrust cover affected topsoil (0-1 cm) P pools (non-occluded P, organic P, calcium bound P, occluded P and total P). Warming significantly increased most P pools-except occluded P-in Aranjuez, whereas only augmented non-occluded P in Sorbas. The rainfall reduction treatment had no effect on the soil P pools at any experimental site. Biocrusts increased most soil P pools and conferred resistance to simulated warming for major P pools at both sites, and to rainfall reduction for non-occluded and occluded P in Aranjuez. Synthesis. Our findings provide novel insights on the responses of soil P pools to warming and rainfall reduction, and highlight the importance of biocrusts as modulators of these responses in dryland ecosystems. Our results suggest that the observed negative impacts of warming on dryland biocrust communities will decrease their capacity to buffer changes in topsoil P driven by climate change.
  • Publication
    Data from: Vascular plants mediate the effects of aridity and soil properties on ammonia-oxidizing bacteria and archaea
    (Oxford, 2013) Delgado Baquerizo, Manuel; Gallardo, Antonio; Wallenstein, Matthew D.; Maestre, Fernando T.
    An integrated perspective of the most important factors driving the abundance of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in natural ecosystems is lacking, especially in drylands. We evaluated how different climatic, abiotic, and nutrient-related factors determine AOA and AOB abundance in bare and vegetated microsites from grasslands throughout the Mediterranean Basin. We found a strong negative relationship between the abundance of AOA genes and soil fertility (availability of C, N, and P). Aridity and other abiotic factors (pH, sand content, and electrical conductivity) were more important than soil fertility in modulating the AOA/AOB ratio. AOB were more abundant under vegetated microsites, while AOA, highly resistant to stressful conditions, were more abundant in bare ground areas. These results suggest that AOA may carry out nitrification in less fertile microsites, while AOB predominate under more fertile conditions. Our results indicate that the influence of aridity and pH on the relative dominance of AOA and AOB genes is ultimately determined by local-scale environmental changes promoted by perennial vegetation. Thus, in spatially heterogeneous ecosystems such as drylands, there is a mutual exclusion and niche division between these microorganisms, suggesting that they may be functionally complementary. Abundance of amoA and amoB genes in soils from Stipa tenacissima grasslands along an aridity gradient in the Mediterranean Data on the abundance of amoA and amoB genes in soils from Stipa tenacissima grasslands along a Mediterranean aridity gradient (from Spain to Tunisia). The database also includes information about different soil variables and the abiotic characteristics of the sites surveyed. All the units and information about the variables are included in the "Metadata" spreadsheet. FEMS_dryad.xls