Spatial and temporal variability of carbon dioxide fluxes in the Alpine Critical Zone: The case of the Nivolet Plain, Gran Paradiso National Park, Italy

Abstract

The dynamics of carbon dioxide fluxes in the high-altitude Alpine Critical Zone is only partially understood. The complex geomorphology induces significant spatial heterogeneity, and a strong interannual variability is present in the often-extreme climatic and environmental conditions of Alpine ecosystems. To explore the relative importance of the spatial and temporal variability of CO2 fluxes, we analysed a set of in-situ measurements obtained during the summers from 2018 to 2021 in four sampling plots, characterised by soils with different underlying bedrock within the same watershed in the Nivolet plain, in the Gran Paradiso National Park, western Italian Alps. Multi-regression models of CO2 emission and uptake were built using measured meteo-climatic and environmental variables considering either individual years (aggregating over plots) or individual plots (aggregating over years). We observed a significant variability of the model parameters across the different years, while such variability was much smaller across different plots. Significant changes between the different years mainly concerned the temperature dependence of respiration (CO2 emission) and the light dependence of photosynthesis (CO2 uptake). These results suggest that spatial upscaling can be obtained from site measurements, but long-term flux monitoring is required to properly capture the temporal variability at interannual scales.

Predicting the productivity of Alpine grasslands using remote sensing information

“…Looking at the different components of Av.LOO in the RS85 model (Table 4), it is clear that much of the complexity was due to the interannual variability, in agreement with Lenzi et al (2023). On the other hand, plot-to-plot variability was low, suggesting the possibility of spatially extrapolating the model to other measurement sites or even different valleys, provided we consider grassland environments.…”

“…The full sampling of a plot required from 1.5 to 2 hours, which have been accounted for when synchronising data from other sources. Further details about the measurement procedure can be found in Magnani et al (2020); Lenzi et al (2023).…”

Carbon dioxide fluxes in Alpine grasslands at the Nivolet Plain, Gran Paradiso National Park, Italy 2017–2023

“…In a related research article titled “ Drivers of carbon fluxes in Alpine tundra: a comparison of three empirical model approaches ” 14 multi-regression models were developed for Gross Primary Production (GPP, defined as GPP = NEE - ER) and Ecosystem Respiration (ER) using average values for each site and each sampling date from years 2017, 2018, and 2019. Further investigations, based on the above-mentioned average values and additional data from CZO@NIVOLET, have also been discussed in “C arbon dioxide exchanges in an alpine tundra ecosystem (Gran Paradiso National Park, Italy): A comparison of results from different measurement and modelling approaches ” 15 and “ Spatial and temporal variability of carbon dioxide fluxes in the Alpine Critical Zone: The case of the Nivolet Plain, Gran Paradiso National Park, Italy ” 16 .…”