17:15 〜 18:45
[ACG37-P05] Influence of artificial summer drought on CO2 fluxes in the Artemisia capillaris community in a coastal dune ecosystem in western Japan
キーワード：気候変動、チャンバー、光合成、海浜植物
The risk of drought is considered to increase due to the changing of rainfall patterns by global climate change, and terrestrial ecosystems will suffer from drought stress more frequently under the conditions. Understanding the feedback of ecosystems to drought stress from the viewpoint of the carbon cycle is important when we consider the future environment and climate change. In this study, we focused on the drought response of CO2 fluxes in the plant community of Artemisia capillaris in a coastal dune ecosystem in western Japan, Tottori, by rainfall interception.
We set four pairs of the rainfall interception plot and the control plot in the study site in the coastal dunes. The size of each plot was 2×3 m including several numbers of Artemisia capillaris in each plot, and we trenched around plots until the depth of 70 cm to insert polycarbonate board to prevent water infiltration. We set roofs consisting of transparent vinyl sheets and steel pipes on rainfall interception plots (3×4 m) in early July 2023, and most of the rainfall in the plots was cut off until mid-October 2023. CO2 fluxes in each plot were measured once or twice a month from July 2023 by using a portable automated chamber measurement system.
Based on the data from July 2023 to January 2024, both gross primary production (GPP) under the clear sky and ecosystem respiration (RE) under complete shading treatment in control plots peaked in mid-September 2023, and they gradually decreased after that until mid-January 2024. On the other hand, GPP and RE in rainfall interception plots continuously decreased from the start of rainfall interception treatment in July 2023 until the end of the treatment in mid-October 2023. The leaf color of Artemisia capillaris gradually turned brown compared with control plots during the rainfall interception, but it did not mean the withering of those plants. That is because GPP in rainfall interception plots slightly recovered in November 2023 after we stopped the rainfall interception. This result suggested the high ability of Artemisia capillaris to survive under drought stress.
We set four pairs of the rainfall interception plot and the control plot in the study site in the coastal dunes. The size of each plot was 2×3 m including several numbers of Artemisia capillaris in each plot, and we trenched around plots until the depth of 70 cm to insert polycarbonate board to prevent water infiltration. We set roofs consisting of transparent vinyl sheets and steel pipes on rainfall interception plots (3×4 m) in early July 2023, and most of the rainfall in the plots was cut off until mid-October 2023. CO2 fluxes in each plot were measured once or twice a month from July 2023 by using a portable automated chamber measurement system.
Based on the data from July 2023 to January 2024, both gross primary production (GPP) under the clear sky and ecosystem respiration (RE) under complete shading treatment in control plots peaked in mid-September 2023, and they gradually decreased after that until mid-January 2024. On the other hand, GPP and RE in rainfall interception plots continuously decreased from the start of rainfall interception treatment in July 2023 until the end of the treatment in mid-October 2023. The leaf color of Artemisia capillaris gradually turned brown compared with control plots during the rainfall interception, but it did not mean the withering of those plants. That is because GPP in rainfall interception plots slightly recovered in November 2023 after we stopped the rainfall interception. This result suggested the high ability of Artemisia capillaris to survive under drought stress.