Historical variation in the normalized difference vegetation index compared with soil moisture in a taiga forest ecosystem in northeastern Siberia

• Published in: Biogeosciences
• Main Authors: Nogovitcyn, Aleksandr, Shakhmatov, Ruslan, Morozumi, Tomoki, Tei, Shunsuke, Miyamoto, Yumiko, Shin, Nagai, Maximov, Trofim C., Sugimoto, Atsuko
• Format: Text
• Language: English
• Published: 2023
• Subjects: Spasskaya; permafrost; taiga; Siberia
• Online Access: https://doi.org/10.5194/bg-20-3185-2023; https://bg.copernicus.org/articles/20/3185/2023/

The taiga ecosystem in northeastern Siberia, a nitrogen-limited ecosystem on permafrost with a dry climate, changed during the extreme wet event in 2007. We investigated the normalized difference vegetation index (NDVI) as a satellite-derived proxy for needle production and compared it with ecosystem parameters such as soil moisture water equivalent (SWE), larch foliar C / N <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="f135772273124e8de131c1d3d27c70de"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-20-3185-2023-ie00001.svg" width="24pt" height="14pt" src="bg-20-3185-2023-ie00001.png"/></svg:svg> ratio, δ 13 C and δ 15 N, and ring width index (RWI) at the Spasskaya Pad Experimental Forest Station in Russia for the period from 1999 to 2019. Historical variations in NDVI showed a large difference between typical larch forest (unaffected) and the sites affected by the extreme wet event in 2007 because of high tree mortality at affected sites under extremely high SWE and waterlogging, resulting in a decrease in NDVI, although there was no difference in the NDVI between typical larch forest and affected sites before the wet event. Before 2007, the NDVI in a typical larch forest showed a positive correlation with SWE and a negative correlation with foliar C / N <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="a1fd226718b6fd2378e4d645ff1b8807"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-20-3185-2023-ie00002.svg" width="24pt" height="14pt" src="bg-20-3185-2023-ie00002.png"/></svg:svg> . These results indicate that not only the water availability (high SWE) in the previous summer and current June but also the soil N availability likely increased needle production. NDVI was also positively correlated with RWI, resulting from similar factors controlling them. However, after the wet event, NDVI ...