Non-invasive monitoring of photosynthetic activity and water content in forest lichens by spectral reflectance data and RGB colors from photographs
| Authors | |
|---|---|
| Year of publication | 2023 |
| Type | Article in Periodical |
| Magazine / Source | Fungal Ecology |
| MU Faculty or unit | |
| Citation | |
| Web | https://doi.org/10.1016/j.funeco.2023.101224 |
| Doi | http://dx.doi.org/10.1016/j.funeco.2023.101224 |
| Keywords | Chlorophyll fluorescence; Desiccation; Lobaria; NDVI; Peltigera; RGB-colors; Reflectance spectra; Quantum yield; Umbilicaria |
| Description | There is a need for non-invasive monitoring of temporal and spatial variation in hydration and photosynthetic activity of red-listed poikilohydric autotrophs. Here, we simultaneously recorded kinetics in RGB-colors (photos), reflectance spectra, water content, maximal (FV/FM), and effective quantum yield of PSII (phi PSII) during desiccation in foliose lichens differing in cortical characteristics and photobionts. The spectral absorbance peaks of chlorophyll a, phycocyanin, and phycoerythrin were clearly displayed at high hydration levels. Brightness and total RGB colors of the lichens strongly increased during desiccation. The normalized difference vegetation index (NDVI) efficiently estimated hydration level and phi PSII - a proxy for lichen photosynthesis - in all species, including threatened old forest lichens. Color and reflectance indices based on green wavelengths gave good estimates of water content in cephalo- and chlorolichens, but not in cyanolichens with a wider range of photosynthetic pigments. Due to species-specific characteristics, species-wise calibration is essential for noninvasive assessments of lichen functioning. |
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