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Strategies shrubby junipers adopt to tolerate drought differ by site

Drought-induced dieback episodes are globally reported among forest ecosystems but they have been understudied in scrublands. Chronically-stressed individuals are supposed to be more vulnerable prior to drought which triggers death. Drought-triggered dieback and mortality events affecting Mediterranean Juniperus phoenicea scrublands were analyzed in two sites with contrasting climate and soil conditions located in Spain. The radial growth patterns of coexisting living and dead junipers, including the calculation of growth statistics used as early-warning signals, quantified growth response to climate, were characterized and the wood C and O isotope discrimination was analyzed. In the inland, continental site with rocky substrates (Yaso, Huesca, N Spain), dead junipers grew less than living junipers about three decades prior to the dieback started in 2016. However, in the coastal, mild site with sandy soils (Doñana, Huelva, SW Spain), dead junipers were smaller but grew more than living junipers about two decades before the dieback onset in 2005. The only common patterns between sites were the higher growth coherence in both living and dead junipers prior to the dieback, and the decrease in growth persistence of dead junipers. Cool and wet conditions in the prior winter and current spring, and cool summer conditions enhanced juniper growth. In Doñana, growth of living individuals was more reduced by warm July conditions than in the case of dead individuals. Higher ?13C values in Yaso indicate also more pronounced drought stress. In Yaso, dead junipers presented lower ?18O values, but the opposite occurred in Doñana suggesting different changes in stomatal conductance prior to death. Warm summer conditions enhance evapotranspiration rates and trigger dieback in this shallow-rooted species, particularly in sites with a poor water-holding capacity. Chronic, slow growth is not always a reliable predictor of drought-triggered mortality. informacion[at]ebd.csic.es: Camarero et al (2020) Dieback and mortality of junipers caused by drought: Dissimilar growth and wood isotope patterns preceding shrub death. Agr Forest Meteorol 291, 108078. DOI 10.1016/j.agrformet.2020.108078


https://www.sciencedirect.com/science/article/pii/S0168192320301805?dgcid=author#ack0001
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Workshop: Developing a priority list of invasive alien species in Europe

Developing a priority list of invasive alien species in Europe

The EU has recently approved its Regulation on the prevention and management of the introduction and spread of invasive alien species, which will come into force in 2015. For successful implementation, the European Commission will need to adopt an EU list of invasive alien species, to be agreed with the Member States. BirdLife Europe, an international organization that promotes conservation science-based, will propose a priority list of species based on the best available evidence of potential impact, and will be achieved through a systematic approach. This task is organized along with the Estación Biológica de Doñana (EBD-CSIC) around two workshops that will be hosted in our premises in Seville on January 21st – 22nd.

Among participants: the universities of Cambridge, Vienna and Berne, the Centre for Environmental Research of Leipzig (UFZ, Germany), the Zoological Society of London, the Academy of Sciences of the Czech Republic, international (EPPO, IUCN) and national organizations (Belgian Biodiversity Platform).