Spatial and temporal variations in respiration rates under experimental warming in alpine meadows of Gangotri National Park, Western Himalaya

The Indian Himalayan region is highly vulnerable to climate warming, which might impact ecological processes and carbon fluxes. Soil respiration (SR), primary component of Ecosystem respiration (ER), is the largest carbon efflux. Despite this, impacts of warming on diurnal respiration rates in alpine meadows of the Indian Himalayan Region remains unexplored. With an emphasis on diurnal patterns, we investigated the spatial and temporal variations in respiration rates under experimental warming in the alpine meadows of Gangotri National Park, Western Himalaya using 18 Open Top Chambers (OTCs) across three sites during May to September 2023. Significant impacts of experimental warming on diurnal SR and ER were observed, with varied site-specific responses. Peak respiration occurred around 12:00 h, followed by a decline in the evening. In both experimental warming and ambient control conditions, ER showed a positive relationship with soil temperature (ST) and a negative relationship with soil water content (SWC). Notably, ant activity was observed as a contributing factor to increased SR in certain plots, highlighting the role of biotic interactions in soil respiration dynamics. We used linear mixed-effects models to assess the contributions of various microclimatic factors to respiration rates. Microclimatic parameters explained about 4.4% and 8% of the variability in SR and ER respectively, which jumped to 85.3% and 85.7% when including spatio-temporal variations. These findings underscore the critical importance of considering spatio-temporal variability and biotic interactions when assessing the influence of microclimatic factors on respiration dynamics in alpine ecosystems. The substantial increase in explanatory power when considering these variations highlights the complex interactions between environmental heterogeneity and ecological processes. This study provides valuable insights into the ecological impacts of climate change in the Indian Himalayan region, demonstrating that experimental warming resulting in a 1.7 °C increase in overall air temperature significantly alters respiration dynamics, thereby emphasizing the urgent need to further investigate the resilience of these alpine meadow ecosystems under changing climatic conditions.