Adaptive Mechanisms of Endemic Fish Triplophysa yarkandensis in the Tarim River Basin of Northwestern China

Abstract

Dryland river ecosystems are among the most susceptible freshwater environments, with climate change, hydrological shifts, salinization and anthropogenic disturbance posing increasing threats to aquatic biodiversity. Endemic fishes in these regions are particularly vulnerable because of restricted geographic range, ecological specialization and narrow environmental tolerance limits, which reduce their capacity to cope with rapid environmental change. Triplophysa yarkandensis has a coordinated set of adaptive responses such as benthic morphological specialization, adaptable trophic modes, osmoregulatory ability to cope with saline–alkaline stress, and thermal tolerance mediated by stress-sensitive genes. Notably, muscle transcriptomic evidence indicates heat-associated expression changes in genes of the IRE1–TRAF2–MAP3K5–JNK signaling axis, suggesting this pathway as a candidate link between endoplasmic-reticulum stress and apoptosis-related responses. But its activation and causal role in apoptosis have not yet been confirmed at the protein and functional level. Nevertheless, these adaptations are increasingly constrained by habitat fragmentation, invasive species, declining water quality, and altered flow regimes, highlighting the limited buffering capacity of endemic species under increasing environmental disturbance. These observations provide a scientific basis for conservation planning, ecological monitoring, and adaptive management in arid inland waters, including habitat restoration, ecological flow regulation, and species-specific protection. Future studies must combine long-term field studies, multi-stressor experimental systems, and genomic–ecophysiological designs to define adaptive limits and improve conservation outcomes under continued climate change.