University thesis:
Dissertation, Friedrich-Schiller-Universität Jena, 2021
Footnote:
Kumulative Dissertation, enthält Zeitschriftenaufsätze
Tag der Verteidigung: 26.03.2021
Zusammenfassungen in deutscher und englischer Sprache
Description:
Plant phenology is regarded as the integrative measure of plant response to environmental changes and also plays an important role in influencing the climate through altering ecosystem structure and functioning (Richardson et al. 2013). However, how the different drivers especially the environmental factors beyond climate and biotic factors influence the phenology is still not revealed. This is particularly challenging in the tree-grass ecosystems in drylands as they have a complex structure and changing the limiting resources throughout the year (Sardans and Peñuelas 2013, Nair et al. 2019). A better understanding of the relationship between drivers and phenology or dynamics of canopy development and functioning is critical importance for us to better predict the land carbon dynamics in the drylands, which is the most important contributor to the trend and interannual variability of global carbon uptake (Ahlstrom et al., 2015; Poulter et al., 2014). By using multiple measurements (field measurements, satellite, PhenoCam, high spectral-resolution spectroradiometer measurements, and eddy covariance (EC) data), we studied the relationship between the canopy structure development (used vegetation indexes (VIs) as the proxies) and functioning dynamics (e.g.dynamics of carbon and water fluxes), and the response of their seasonality metrics to different drivers in a Mediterranean tree-grass ecosystem. Through the large nutrient manipulation experiment, we investigated how nutrients and water availability co-shapes the seasonality of greenness and ecosystem functioning. By probing the spectral properties of evergreen leaves, we tested if the leaf age plays a critical role in regulating the tree canopy greenness.