Field experiment reveals complex warming impacts on giant pandas' bamboo diet

Understanding the impacts of global warming on keystone species is fundamental to addressing the threat of climate change to biodiversity. Understory bamboo species play a crucial role in many forest ecosystems and provide food and shelter for numerous animals, including the giant panda (Ailuropoda melanoleuca). While previous studies projected that global warming would cause substantial shrinkage of bamboo distribution and threaten giant pandas, substantial uncertainties persist due to an incomplete understanding of the impacts of warmer temperatures on both the quantity and quality of bamboo as the food source for giant pandas. To address this research gap, we conducted the first field experiment in giant panda habitats to assess the impacts of warmer temperatures on the population dynamics and dietary quality of arrow bamboo, a main food source of giant pandas. We observed that warming generated a nonlinear impact on bamboo survival, with a potential warming threshold between 1.5 °C and 3 °C, beyond which warmer temperatures substantially reduced the survival rate of bamboo. Additionally, our plant content analysis showed that warmer temperatures lowered bamboo's nutritional value but enhanced its palatability as food for giant pandas. Furthermore, we found that warming could jeopardize the bamboo food supply for giant pandas by intensifying aphid infections in bamboo. These findings advanced the understanding of food web dynamics under global warming and provided crucial information for effective giant panda conservation planning in the face of climate change.