Impacts of abiotic and biotic factors on tundra productivity near Utqiaġvik, Alaska

• Published in: Environmental Research Letters
• Main Authors: Qingyuan Zhang, Xuesong Zhang, Mark J Lara, Zhengpeng Li, Jingfeng Xiao, Kaiguang Zhao, Tongxi Hu
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2023
• Subjects: Arctic tundra; earlier snowmelt; warming; lemming herbivory; fAPARchl; productivity; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Arctic; Tundra; Alaska
• Online Access: https://doi.org/10.1088/1748-9326/acf7d6; https://doaj.org/article/17b20a227b9a47f58c92ff4681f121c7

Earlier snowmelt, warmer temperatures and herbivory are among the factors that influence high-latitude tundra productivity near the town of Utqiaġvik in northern Alaska. However, our understanding of the potential interactions between these factors is limited. MODIS observations provide cover fractions of vegetation, snow, standing water, and soil, and fractional absorption of photosynthetically active radiation by canopy chlorophyll (fAPAR _chl ) per pixel. Here, we evaluated a recent time-period (2001–2014) that the tundra experienced large interannual variability in vegetation productivity metrics (i.e. fAPAR _chl and APAR _chl ), which was explainable by both abiotic and biotic factors. We found earlier snowmelt to increase soil and vegetation cover, and productivity in June, while warmer temperatures significantly increased monthly productivity. However, abiotic factors failed to explain stark decreases in productivity during August of 2008, which coincided with a severe lemming outbreak. MODIS observations found this tundra ecosystem to completely recover two years later, resulting in elevated productivity. This study highlights the potential roles of both climate and herbivory in modulating the interannual variability of remotely retrieved plant productivity metrics in Arctic coastal tundra ecosystems.