Low‐trophic level fishes and riverbank trees showed similar growth responses to climate warming on the Tibetan Plateau

Abstract

AbstractHow neighbouring aquatic and terrestrial ecosystems respond to climate change in the same area remains poorly explored, fundamentally constraining our understanding of cross‐ecosystem processes, prediction capabilities and catchment management. This study simultaneously explored how the growth of three fish species at different trophic levels and one riverbank juniper species responds to the climate in the upper Nu‐Salween River. Biochronologies and hierarchical linear mixed‐effects models were used to resolve the contribution of three sources (i.e. random, fixed intrinsic and fixed extrinsic effects) to growth variations. The optimal models explained higher percentages of the annual growth variabilities for fishes (63.1%–90.1%) than for juniper (28.2%). All the growth chronologies showed temporal variations after eliminating the fixed intrinsic effects, and for fishes, extra cohort effects were observed. Age was the major fixed intrinsic factor affecting growth variations for fishes but not for trees. All females showed clearly faster growth than males for all fishes at all ages. Among fixed extrinsic effects, temperature showed a consistent significant correlation with the growth of lower‐trophic level fishes and juniper but not with that of the higher‐trophic level fish. Only one global variable (i.e. El Niño Southern Oscillation) exerted a significant negative effect on the growth of the higher‐trophic level fish. The results suggest that fishes may be more sensitive to climate change than terrestrial trees, and the similarity in the growth response across ecosystems likely depends on trophic levels, which should be highlighted in related predictions and catchment management.