Assessing Potential Habitat Suitability of the Endangered Endo-Holoparasitic Sapria himalayana and Its Multiple Hosts in China Under Global Warming

Global warming severely threatens parasitic plants worldwide. However, little is known about how a parasite with multiple hosts responds to climate change in its distribution. Sapria himalayana is an endangered endo-holoparasite, obligately parasitizing Tetrastigma species. We employed MaxEnt to predict suitable habitats for S. himalayana and its five hosts, and determined key environmental factors. Then, we calculated niche overlaps for the five parasite-host pairs. Currently, it covers a suitable area of 1.35 × 104 km2, accounting for 0.14% of China’s total territory. Temperature-related variables were identified as the key factors shaping potential distribution for this parasite and three hosts (i.e., T. planicaule, T. obovatum, and T. cruciatum), while precipitation-related ones were identified for the other hosts (i.e., T. obtectum and T. serrulatum). Collectively, the five pairs presented low niche overlaps under current and future scenarios. While S. himalayana will increase by 37.78% in future suitable habitat, the two host categories show contrasting trends in potential habitat shifts. Divergent climatic sensitivities across host species, along with parasite–host suitability mismatches, could shape the survival and distribution of S. himalayana. Consequently, this research offers valuable insights for the conservation of S. himalayana in China, highlighting the necessity of safeguarding its distinct hosts under global warming.