Effects of manipulative prolonged temperature increase on the greater long-tailed hamster (

Global climate change has caused range shifts and population declines in various species. However, causal evidence from manipulative studies, particularly for vertebrates, remains scarce. Prolonged temperature increases, a direct consequence of climate change, pose significant challenges to species adaptation and survival. We examined the effects of prolonged temperature increases on reproduction, physiology, and behavior adaption in the greater long-tailed hamster using semi-natural enclosures where temperature was manipulated via plastic roofs and windows, creating a greenhouse effect without affecting rainfall. We analyzed data using grouped enclosures (low temperature, LT; high temperature, HT), which showed that prolonged temperature increases led to reduced reproductivity per capita during the breeding season. In addition, prolonged temperature increases reduced night-time activity in founder hamsters during overwintering, increased burrow depth during the breeding season, and raised testicular weights in founder males during the overwintering season. Our study provides experimental evidence that prolonged temperature increases negatively impact population growth of greater long-tailed hamsters by inducing temperature stress and impairing reproductive performance, highlighting the need to address heat stress in wildlife management under climate warming.