Med-N-Change · Assessing the Interactive Effects on N Addition and Climate Change on Soil Processes through the Biological Soil Crust in Mediterranean Ecosystems

Assessing the Interactive Effects on N Addition and Climate Change on Soil Processes through the Biological Soil Crust in Mediterranean Ecosystems

Issue being addressed: Ecosystems located in the Mediterranean basin are expected to experience important changes in the rainfall frequency and to increase its nitrogen inputs due mainly to the intensification of agriculture and the burning of fossil fuels. Despite many efforts have been made to understand the effects that each one of these factors of global change would have on our ecosystems, it is unknown how they would respond to both factors at the same time. Previous studies have pointed out that the isolated effect of global change drivers could be substantially different from those resulting from their interaction. Soil in these ecosystems is usually covered by a natural and living “carpet” composed by lichens, cyanobacteria, mosses and/or algae, among other organisms. It is called the soil biocrust. Recent research has pointed out that the effect that global change has on the functioning of our ecosystems might be different depending on the presence or absence of the biocrust and on its composition. Thus, the benefits that humans freely gain from properly functioning ecosystems could be more or less protected depending on what organisms are composing the soil biocrust in a given ecosystem. Overall objectives: Med-N-Change intends to reply to the following questions: What are the joint effects of climate change and nitrogen inputs on soil processes in Mediterranean ecosystems? What is the role of the soil biocrust and its components in protecting soil processes from the joint effects of increased nitrogen and climate change? How are ecosystem services affected? Another objective of this project is to disseminate and educate citizens about the importance of soil biocrust and functioning. Why is it important for society? Answering those questions will have important implications on environmental policies and prediction of global change scenarios, with the ultimate societal objective of improving ecosystem management in Mediterranean ecosystems. By improving the management of these areas, the ecosystem services provided by them will more protected and citizens will be able to keep benefiting from having a healthy environment. Conclusions: For soil lichens, we found that reduced watering decreases its vitality, whereas nitrogen addition unexpectedly helped lichens subjected to reduced watering to cope with stress produced by high temperatures. We also found that long-term exposure to nitrogen addition allowed lichens to acclimatize to higher nitrogen availability. Interactions between reduced watering and increased nitrogen supply and temperature have an important potential to harm the functioning of soil lichens (Morillas et al., 2022). For epiphytic lichens, our results suggested that whatever their characteristics were, all species responded with detrimental effects to nitrogen addition, and were unable to recover following sunlight and ultraviolet exposure. Moreover, solar radiation made a tolerant species more sensitive to the detrimental effects of nitrogen pollution. Our results draw attention to the combined effects of global change and other environmental drivers on canopy defoliation and tree death, with consequences for the protection of ecosystems (Morillas et al., 2021).

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз