Contrasting 20-year trends in NDVI at two Siberian larch forests with and without multiyear waterlogging-induced disturbances

Autor: Hirohiko Nagano, Ayumi Kotani, Hiroki Mizuochi, Kazuhito Ichii, Hironari Kanamori, Tetsuya Hiyama
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Environmental Research Letters, Vol 17, Iss 2, p 025003 (2022)
Druh dokumentu: article
ISSN: 1748-9326
DOI: 10.1088/1748-9326/ac4884
Popis: The fate of a boreal forest may depend on the trend in its normalized difference vegetation index (NDVI), such as whether the NDVI has been increasing significantly over the past few decades. In this study, we analyzed the responses of two Siberian larch forests at Spasskaya Pad and Elgeeii in eastern Siberia to various waterlogging-induced disturbances, using satellite-based NDVI and meteorological data for the 2000–2019 period. The forest at Spasskaya Pad experienced waterlogging (i.e. flooding events caused by abnormal precipitation) during 2005–2008 that damaged canopy-forming larch trees and increased the abundance of water-resistant understory vegetation. By contrast, the forest at Elgeeii did not experience any remarkable disturbance, such as tree dieback or changes in the vegetation community. Significant increasing NDVI trends were found in May and June–August at Elgeeii ( p < 0.05), whereas no significant trends were found at Spasskaya Pad ( p > 0.05). NDVI anomalies in May and June–August at Elgeeii were significantly associated with precipitation or temperature depending on the season ( p < 0.05), whereas no significant relationships were found at Spasskaya Pad ( p > 0.05). Thus, the 20 year NDVI trend and NDVI–temperature–precipitation relationship differed between the two larch forests, although no significant trends in temperature or precipitation were observed. These findings indicate that nonsignificant NDVI trends for Siberian larch forests may reflect waterlogging-induced dieback of larch trees, with a concomitant increase in water-resistant understory vegetation.
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