Predicting the suitable distribution of Russula griseocarnosa in China based on Maxent model

Russula griseocarnosa is a wild medicinal edible ectomycorrhizal fungus. Its current and future distributions are unclear. Based on the distribution data, we used the optimized MaxEnt model to predict the potential sui-table habitat of R. griseocarnosa under current and future climate conditions, and evaluate the important environmental factors driving its distribution pattern in China. The results showed that the area of the receiver operating characteristic curve was greater than 0.9, indicating that the model were highly reliable. The most important environmental factor affecting the distribution of R. griseocarnosa was the average temperature of the coldest quarter, with a contribution rate of 46.5%, and the suitable growth threshold was 7.3-18.2 ℃, followed by the average temperature of the wettest quarter, soil base saturation, and precipitation in the coldest quarter with contribution rates of 17.4%, 12.9%, and 6.9%. Their suitable ranges were 16.5-27.4 ℃, 6.9%-53.3%, and 74.1-269.4 mm respectively. The cumulative contribution rate of those factors reached 83.7%. Under the current climate scenario, the suitable habitat area of R. griseocarnosa was 40.47×10⁵ km². Among them, the areas of the highly suitable habitat, moderately suitable habitat, and lowly suitable habitat were approximately 6.58×10⁵, 20.98×10⁵ , and 26.56×10⁵ km², respectively. Highly suitable habitat mainly distributed in provinces such as Yunnan, Guangxi, Guangdong, and Fujian. Under future climate change, the suitable habitat areas of R. griseocarnosa would show an increasing trend. Under the SSP3-7.0 (2070s) scenario, the total area of the suitable habitat would reach the maximum, which was approximately 69.97×10⁵ km². In the future, the centroid of R. griseocarnosa exhibited an overall migration to the northeast, with a trend from low latitudes to high latitudes.