Catchment based analysis of macronutrients (nitrogen and phosphorus) and organic carbon dynamics: new modelling and participatory tools

Ecosystem services (ESs) are increasingly being considered in decision-making with respect to mitigating future climate impacts. To capture complex variation in spatial and temporal dynamics, ecosystem models require spatially explicit data that are often difficult to obtain for model development and validation. Citizen science allows for the participation of trained citizen volunteers in research or regulatory activities, resulting in increased data collection and increased participation of the general public in resource management. Despite the increasing experience in citizen science, these approaches have seldom been used in the modelling of provisioning ecosystem services. The development of new approaches for the analysis of long-term changes in riverine carbon, hydrological and nutrient cycles is important to identify potential alteration on the biogeochemical cycles and potential impacts on the ecosystem services provided to the local population. The Basin scale approach is useful to evaluate the pressures on river ecosystems that may be distant from the receiving watercourse, including the effects of soil or water management activities that propagate or amplify downstream. However, the lack of process-based and basin-scale models for carbon transport has limited effective basin management of organic carbon fluxes from soils, through river networks and to receiving marine waters. In the present study, were examined the temporal and spatial drivers in macronutrient (nitrogen and phosphorus) and sediment delivery, carbon storage and sequestration and water yield in a major Italian river catchment and under different NBS scenarios. Information on climate, land use, soil and river conditions, as well as future climate scenarios, were used to explore future (2050) benefits of NBS on local and basin scales, followed the national and European directives related to water quality (Directive 2000/60/EC) and habitat (Directive 92/43/EEC). It was developed and validate a spatially semi-distributed mass balance modelling approach to estimate organic carbon delivery at a sub-basin scale and which allows exploration of alternative river basin management scenarios and their impact on DOC and POC dynamics. The model is built as an open-source plugin for QGIS and can be easily integrated with other basin scale decision support models on nutrient and sediment export. Furthermore, was performed an estimation of the benefits of individual and combined NBS approaches related to river restoration and catchment reforestation. To complete the ESs overall evaluation and prioritization was developed a new method in order to attributing a weight to the best NBS scenarios based on the natural stoichiometric ratio between the elements carbon, silicon, nitrogen, phosphorus (C:Si:N:P)