Analyzing the effect of the duration of soil warming on subarctic grasslands using high-resolution multispectral images

Abstract

Climate change is causing rapid changes in sub-Arctic and Arctic terrestrial ecosystems compared to the other biomes. As these ecosystems are so sensitive to climate change, more research on how the rising of temperature affects these ecosystems is essential.This study is implemented in the ForHot research site located in Iceland encompassing geothermally heated natural grasslands. This research site contains two areas, one that has been warmed geothermally for over 60 years (long-term warming; LTW) and the other since 2008 (medium-term warming; MTW). The LTW area contains 24 plots and the MTW contains 30 plots, with the mean annual soil temperature ranging between 5 to 21 °C for LTW and 6 to 46 °C for MTW in 2022. The main goal of this study was to understand how the warming level and the duration of warming (MTW vs. LTW) have affected the average seasonal Normalized Difference Vegetation Index (NDVI) during 2022.For this study, we repeatedly collected high-resolution multispectral data using Micasense dual camera system and DJI Matrice 600 drone each month from April 2022 to October 2022 as well as soil temperature data of each plot, and some other parameters such as precipitation, air temperature, wind speed, and soil water content.Here we present the results on how the warming level and the duration of warming affected the monthly and seasonal average NDVI in the MTW and LTW grassland ecosystems.