PublicationData 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 PublicationData from: Behaviour-related DRD4 polymorphisms in invasive bird populations(Dryad, 2014-05-23) Mueller, Jakob C.; Edelaar, Pim; Carrete, Martina; Serrano, David; Potti, Jaime; Blas, Julio; Dingemanse, Niels J.; Kempenaers, Bart; Tella, José LuisIt has been suggested that individual behavioural traits influence the potential to successfully colonize new areas. Identifying the genetic basis of behavioural variation in invasive species thus represents an important step towards understanding the evolutionary potential of the invader. Here, we sequenced a candidate region for neophilic/neophobic and activity behaviour - the complete exon 3 of the DRD4 gene - in 100 Yellow-crowned bishops (Euplectes afer) from two invasive populations in Spain and Portugal. The same birds were scored twice for activity behaviour while exposed to novel objects (battery or slice of apple) in captivity. Response to novel objects was repeatable (r = 0.41) within individuals. We identified two synonymous DRD4 SNPs that explained on average between 11% and 15% of the phenotypic variance in both populations, indicating a clear genetic component to the neophilic/neophobic/activity personality axis in this species. This consistently high estimated effect size was mainly due to the repeated measurement design, which excludes part of the within-individual nongenetic variance in the response to different novel objects. We suggest that the alternative alleles of these SNPs are likely introduced from the original population and maintained by weak or antagonistic selection during different stages of the invasion process. The identified genetic variants have not only the potential to serve as genetic markers of the neophobic/neophilic/activity personality axis, but may also help to understand the evolution of behaviour in these invasive bird populations. PublicationData 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, LorenaAn 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.