Distribution patterns of Abietinella species under climate change across multiple spatiotemporal scales based on...

Abietinella, a dominant genus in the understory, only comprises two species Abietinella abietina (Hedw.) Fleisch. and Abietinella hystricosa (Mitt.) Broth. They can influence forest regeneration and development. However, research on the geographical distribution patterns of Abietinella is limited, which led to the absence of a method that can help explore how climate change affects the progress of species speciation and species diversity and their ecological functions for Abietinella.

We compared the performance of different ecological niche models and then chose MaxEnt, which had the best performance, to analyze the effects of key environmental factors on the distribution patterns of Abietinella species and to simulate the distribution patterns of the two Abietinella species in China during the paleoclimate, current, and even future (2100) periods.

The results indicated that (1) temperature may play a more important role than precipitation in both species' distribution. Isothermality and precipitation of the driest month are the most important factors defining the distribution pattern of A. hystricosa, and mean temperature of the wettest quarter and precipitation of the warmest quarter are the most important factors for A. abietina; (2) No matter which period is considered, the distribution probabilities of A. abietina are obviously lower than those of A. hystricosa. For A. hystricosa, the areas of moderately suitable habitat showed a decreasing trend during the paleoclimate period but are projected to show an increasing trend in the 2100s. By contrast, A. abietina was predicted to remain stable from moderate to high suitability across all periods; (3) Across different spatiotemporal scales, both A. abietina and A. hystricosa had the largest potential distribution areas in the paleoclimate period. In addition, the two species exhibited largely consistent migration directions from the Last Glacial Maximum to future scenarios, except under the future ssp245 scenarios. A. hystricosa had a significantly longer distance migration than A. abietina under the paleoclimate, while A. abietina exhibited a longer migration distance than A. hystricosa under future climate scenarios.

Our results provide a research foundation for the study of bryophyte differentiation across large spatiotemporal scales under climate change.