The impact of warming on peak‐season ecosystem carbon uptake is influenced by dominant species in warmer sites

Abstract Climatic warming affects ecosystem‐scale carbon fluxes directly through its impact on photosynthesis and respiration, and indirectly by altering the plant community. This study reports on a 10‐year factorial warming and dominant plant species removal experiment conducted in a high‐ and a low‐elevation montane meadow to explore how dominant plants modify the effect of warming on the carbon cycle over time and in different locations. At the low‐elevation site, warming increased peak‐season net carbon uptake in most years, primarily due to higher primary productivity. This effect was observed only in plots where the dominant species was present. Net ecosystem carbon uptake was generally positive, but it often shifted from net carbon uptake to net carbon release when the dominant species was removed, particularly in dry years. Surprisingly, the high‐elevation site showed no response to the warming or plant removal treatments. Synthesis : These findings highlight that dominant plant species can modify the impacts of warming on carbon fluxes. However, the effects of warming and plant species removal on the carbon cycle vary spatially and temporally. This study provides valuable insights into how both abiotic and biotic factors influence ecosystem carbon cycling and source‐sink dynamics.