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

Abstract

How 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.

Spawning cohort trade‐offs of reproductive time and output in cyprinid fish along an elevation gradient

“…It originates at the foot of the Wahe Mountains in the southern part of Leiwuqi County and flows through the Taniantaweng Mountain area in the eastern part of Tibet before merging into the Nu‐Salween River at Chawalong (He & Tang, 2000). The upper Nu‐Salween River is subject to the monsoon, which makes air temperature extremely seasonal (monthly mean value ranges from −12 to 22°C) and rainfall patterns highly variable from year to year, ranging from 50 to 2100 mm (Tao, Huang, et al., 2023).…”

“…The upper Nu-Salween River is subject to the monsoon, which makes air temperature extremely seasonal (monthly mean value ranges from −12 to 22°C) and rainfall patterns highly variable from year to year, ranging from 50 to 2100 mm (Tao, Huang, et al, 2023).…”

“…Extreme cold, severe aridity, and a lack of oxygen characterize the environment in this region (Kang et al., 2010). These factors coupled with the fragile nature of its ecosystems, render the ecological environments and biota on the Qinghai‐Tibetan Plateau highly susceptible to the effects of global climate change, with limited capacity for recovery once damaged (Tao, Huang, et al., 2023; Xia et al., 2021). Schizothoracine fishes (Cypriniformes: Cyprinidae: Schizothoracinae) are an important group of freshwater fish within the region, with over a hundred species widely distributed in the Qinghai‐Tibetan Plateau.…”

“…It may be the last refuge for many endemic and migratory fish species (Ding, Tao, et al., 2023). The upper part of the basin provides diverse habitats for schizothoracine fishes, including Schizopygopsis thermalis , a highly specialized cold‐water species endemic to the Tibetan Plateau (Tao, Huang, et al., 2023) with a wide elevational range (2214–4800 m; Liu et al., 2020; Wu & Wu, 1992). As an omnivorous species, S. thermalis mainly feeds on benthic algae and detritus, as well as a small proportion of aquatic insect larvae and fish juveniles (Tao, Huang, et al., 2023).…”

“…The upper part of the basin provides diverse habitats for schizothoracine fishes, including Schizopygopsis thermalis, a highly specialized cold-water species endemic to the Tibetan Plateau (Tao, Huang, et al, 2023) with a wide elevational range (2214-4800 m;Liu et al, 2020;Wu & Wu, 1992). As an omnivorous species, S. thermalis mainly feeds on benthic algae and detritus, as well as a small proportion of aquatic insect larvae and fish juveniles (Tao, Huang, et al, 2023). S. thermalis is the dominant fish species in the Yuqu sub-basin, a major tributary of the upper Nu-Salween, and is also the most commercially important fish in the sub-basin (Zhang & Xing, 1996).…”