Carbon and Water Use Efficiency in Changing Climate Conditions: An Spatio-Ecological Resilience Approach for the SAARC Region

In recent decades, South Asian countries are witnessed unusual climate phenomena of increases in temperature and changing rainfall patterns. If adverse climate conditions prevail for a long period of time, an ecosystem becomes vulnerable in terms of primary productivity. The carbon and water use efficiency (CUE and WUE, respectively) are one of the key parameters to detect the impact of hydrological stress on ecosystem productivity. The current study is an attempt to investigate ecosystem resiliency at different scales in the SAARC region under hydrological stress conditions utilizing water and carbon use efficiency as indicating measures. The study included remote sensing datasets such as MODIS multispectral data products and gridded data of climatic parameters. The results of mean annual WUE and CUE for the research period (2001-2021) were found 0.66 ± 0.34 g C kg-1 H2O and 0.45 ± 0.21 (unitless), respectively. The spatio-temporal results depict that the water and carbon use efficiency is not affected in a very short period of time. Both have a strong but indirect relationship with climatic parameters like precipitation, land surface temperature, and actual and potential evapotranspiration. Potential evapotranspiration was found having the highest negative correlation with water and carbon use efficiency.