Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.5194/bg-22-2935-2025 |
Licence  |
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| Title (Primary) | Altered seasonal sensitivity of net ecosystem exchange to controls driven by nutrient balances in a semi-arid savanna |
| Author | Nadolski, L.; El-Madany, T.S.; Nelson, J.; Carrara, A.; Moreno, G.; Nair, R.; Luo, Y.; Hildebrandt, A.; Rolo, V.; Reichstein, M.; Lee, S.-C. |
| Source Titel | Biogeosciences |
| Year | 2025 |
| Department | CHS |
| Volume | 22 |
| Issue | 12 |
| Page From | 2935 |
| Page To | 2958 |
| Language | englisch |
| Topic | T5 Future Landscapes |
| Supplements | https://bg.copernicus.org/articles/22/2935/2025/bg-22-2935-2025-supplement.pdf |
| Abstract | Semi-arid ecosystems dominate the variability and trend of the terrestrial carbon sink. They are sensitive to environmental changes following anthropogenic influences, such as an altered ratio of nitrogen (N) to phosphorus (P) due to increasing N deposition. Semi-arid savannas with different vegetation compositions have complex carbon flux dynamics, and their responses to environmental change are not yet well understood. We analyzed a long-term (2016–2022/2023) dataset of flux, biometeorological, and vegetation data (satellite and ground measurements) from a manipulated semi-arid savanna to examine how altered nutrient levels and stoichiometric balance affect the seasonal sensitivity of net ecosystem exchange (NEE) to its drivers. We used singular spectrum analysis to extract the seasonal signals of all variables and assessed the key drivers of NEE over the study period as a whole and in different seasons, using Pearson correlation and information theory. We found that the addition of both N and N + P to the ecosystem increased seasonal NEE variability, driven by greenness of the herbaceous layer. Analyzing 7 years of combined data, we found that the water limitation in summer and the energy limitation in winter outcompeted the fertilization effect. We learned that the effects of nutrient addition on NEE–control relationships became clearer through analyzing different phenological seasons. In the summer, N + P addition led to a potential change in species composition and productivity, resulting in a stronger interaction between the herbaceous layer and NEE. During the transitional seasons (i.e., drydown and autumn), which mark the senescence and regreening of the herbaceous layer, we found NEE to be less sensitive towards meteorological drivers like relative humidity, radiation, and air temperature with N addition. In the future, the increasing NEE variability might become even more pronounced with increasing N deposition and a changing climate. |
| Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=31022 |
| Nadolski, L., El-Madany, T.S., Nelson, J., Carrara, A., Moreno, G., Nair, R., Luo, Y., Hildebrandt, A., Rolo, V., Reichstein, M., Lee, S.-C. (2025): Altered seasonal sensitivity of net ecosystem exchange to controls driven by nutrient balances in a semi-arid savanna Biogeosciences 22 (12), 2935 - 2958 10.5194/bg-22-2935-2025 |
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