As an important Tibetan medicine and a secondary protected plant in China, Pomatosace filicula is endemic to the country and is mainly distributed in the Qinghai–Tibet Plateau (QTP). However, global climate change caused by greenhouse gas emissions might lead to the extinction of P. filicula. To understand the potential spatial distribution of P. filicula in future global warming scenarios, we used the MaxEnt model to simulate changes in its suitable habitat that would occur by 2050 and 2070 using four representative concentration pathway (RCP) scenarios and five global climate models. The results showed that the QTP currently contains a suitable habitat for P. filicula and will continue to do so in the future. Under the RCP2.6 scenario, the suitable habitat area would increase by 2050 but shrink slightly by 2070, with an average reduction of 2.7%. However, under the RCP8.5 scenario, the area of unsuitable habitat would expand by an average of 54.65% and 68.20% by 2050 and 2070, respectively. The changes in the area of suitable habitat under the RCP4.5 and RCP6.0 scenarios were similar, with the unsuitable area increasing by approximately 20% by 2050 and 2070. Under these two moderate RCPs, the total suitable area in 2070 would be greater than that in 2050. The top three environmental factors impacting the habitat distribution were altitude, annual precipitation (BIO12) and annual temperature range (BIO7). The cumulative contribution rate of these three factors was as high as 82.8%, indicating that they were the key factors affecting the distribution and adaptability of P. filicula, P. filicula grows well in damp and cold environments. Due to global warming, the QTP will become warmer and drier; thus, the growing area of P. filicula will move toward higher elevations and areas that are humid and cold. These areas are mainly found near the Three-River Region. Future climate change will aggravate the deterioration of the P. filicula habitat and increase the species’ survival risk. This study describes the distribution of P. filicula and provides a basis for the protection of endangered plants in the QTP.

Anisodus tanguticus (Maxim.) Pascher, a medicinal plant growing in the Tibetan Plateau region with various medicinal values, is mainly used for the extraction of tropane alkaloids (TAs), and the increased demand for A. tanguticus has triggered its overexploitation. The cultivation of this plant is necessary for the quality control and conservation of wild resources. During 2020 and 2021, a split-plot experiment with three replicates was used to study different planting densities (D1: 30 × 50 cm; D2: 40 × 50 cm; D3: 50 × 50 cm; D4: 60 × 50 cm) and different growth periods (first withering period: October 2020; greening period: June 2021; growth period: August 2021; second withering period: October 2021) on the yield and alkaloid content (atropine, scopolamine, anisodamine, anisodine) of A. tanguticus. The results showed that the mass per plant of A. tanguticus was higher at low density, while the yield per unit area of the underground parts (25288.89 kg/ha) was greater at high density, and the mass of the aboveground parts (14933.33 kg/ha) was higher at low density. The anisodamine (0.0467%) and anisodine (0.1201%) content of D2 (40 cm × 50 cm) was significantly higher than that of the other densities during the green period. The content of all four alkaloids was highest during the greening period, and the scopolamine, anisodamine, and anisodine content was higher in the aboveground parts than in the underground parts. The total alkaloid accumulation per unit area of the whole plant reached its maximum value (1.08%, 139.48 kg/ha) in the growth period of D2; therefore, for economic efficiency and the selection of the best overall quality, it was concluded that the aboveground parts also had medicinal value, the growth period was the best harvesting period, and D2 (40 cm × 50 cm) was the best planting density for A. tanguticus.