Nutrient inputs in Arctic lake ecosystems will be affected by changes in snow coverage and abundance of migratory birds associated to climate warming, with implications for the stability of lake food webs and the ecosystem services they provide both at the local and the global scale (e.g. carbon sequestration). Through field experiments, satellite data and modelling, the project will quantify the effects of seasonal snow cover and bird abundance on the origin and quantity of nutrient inputs in high Arctic lakes, and the consequent variations of food web structure, including key topological properties affecting their stability and productivity (e.g. complexity, food chain length). Notably, these issues are not only of interest in Arctic lakes, having the potential to improve predictions on how lake food webs will respond to changes in nutrient inputs at lower latitudes. C and N stable isotope data, high-resolution satellite and field images for bird abundance, snow and vegetation coverage will be collected in the area of Ny-Alesund, Svalbard, to reconstruct the structure of lake food webs and to quantify the importance of aquatic and/or terrestrial nutrient inputs to aquatic primary consumers.
Results will add important information to international and national research actions, including the European project iCUPE, the Terrestrial Ecology flagship of the NySMAC, and the Italian Arctic Research Program. Data and maps will provide an important contribution for hydrological and ecological studies on Arctic freshwater ecosystems, and a necessary baseline to inform future monitoring and conservation plans. Datasets, maps and technical reports on methodologies developed will be made available to the scientific community, being of interest for studies carried out both across the Arctic and in Antarctica.
Anticipating effects of climate change on Arctic lake food webs is necessary to conserve Arctic biodiversity and ecosystem services provided to Arctic human populations and at the global scale. This project will provide mechanism-based evidence on effects of seasonal snow cover and migratory birds on the origin of nutrient inputs fueling Arctic lake communities and their effect on the structure and functioning of food webs. The combination of field measurements, experiments, in situ and satellite image acquisition, and data modelling for the study of lake ecosystems represents a scientific novelty both in polar regions and at lower latitudes. Such interdisciplinary approach will enable to understand how and how much the changes in the above mentioned factors will affect the complexity and stability of food webs, and hence their biodiversity and productivity.
Isotopic analyses of sediment, primary producers, aquatic consumers and bird feces will provide an unprecedented characterisation of nutrient inputs and transfer in Arctic lake food webs, clarifying their dependence on abiotic (snow melting) and biotic (migratory birds) factors affected by climate change. Field experiments will provide up to date characterization of trophic structures, enabling comparisons across the Arctic, and with food web structures from lower latitudes and from Antarctic already owned by the research group (Calizza et al., 2012; Rossi et al., 2015; Costantini et al. 2018; Sporta Caputi et al., 2020).
Snow cover distribution will be derived using new generation satellite data (Sentinel 2). Satellite data will be merged with terrestrial images taken from the automatic instrumentation available in the study area. The terrestrial images will be both new and derived from the iCupe project, enabling a continuous monitoring of the distribution of the snowpack area. This will help to determine the beginning of the melting season, and to monitor the evolution of vegetation cover. Products of image processing will be integrated with field data to quantify the contribution of snow melting (Snow Water Equivalent, SWE) to the hydrological cycle, as a main driver of nutrient cycling in watersheds.
Produced data and maps will provide an important contribution for hydrological and ecological studies on Arctic freshwater ecosystems, and a necessary baseline to inform future monitoring and conservation plans. Datasets, maps and technical reports on methodologies developed during the project will be made available to the scientific community, being of interest for studies carried out both across the Arctic and in Antarctica.
References for this section:
Calizza, E., Costantini, M. L., Rossi, D., Carlino, P., & Rossi, L. (2012). Effects of disturbance on an urban river food web. Freshwater Biology, 57(12), 2613-2628.
Costantini, M. L., Carlino, P., Calizza, E., Careddu, G., Cicala, D., Sporta Caputi, S., ... & Rossi, L. (2018). The role of alien fish (the centrarchid Micropterus salmoides) in lake food webs highlighted by stable isotope analysis. Freshwater Biology, 63(9), 1130-1142.
Sporta Caputi, S., Careddu, G., Calizza, E., Fiorentino, F., Maccapan, D., Rossi, L., & Costantini, M. L. (2020). Seasonal food web dynamics in the Antarctic benthos of Tethys Bay (Ross Sea): implications for biodiversity persistence under different seasonal sea-ice coverage. Frontiers in Marine Science, 7, 1046.
Rossi, L., di Lascio, A., Carlino, P., Calizza, E., & Costantini, M. L. (2015). Predator and detritivore niche width helps to explain biocomplexity of experimental detritus-based food webs in four aquatic and terrestrial ecosystems. Ecological Complexity, 23, 14-24.