Abstract: Desert moss crusts are patchily distributed on the desert surface, playing key roles in stabilizing soils, improving nutrient cycling and biodiversity, and maintaining the overall stability of desert ecosystems. In this study, we measured plant stoichiometric characteristics at the edge, middle, and central circles of Syntrichia caninervis crust patches across four sites differing in mean annual precipitation in the Gurbantunggut Desert. We further analyzed the differences in stoichiometric characteristics among the various circles within the patches and their responses to environmental factors. There were significant differences in the stoichiometric characteristics of moss plants across different circles within desert moss crust patches. The magnitude and pattern of these differences varied with mean annual precipitation. The edge effect rate (r) of stoichiometric characteristics differed significantly among sites differing in mean annual precipitation. The stoichiometric characteristics and edge effect rates of different circles within the moss crust patches responded differently to environmental factors. Specifically, wind speed had a significant impact (P<0.01) on the effect rate from the edge to the central circle of desert moss crust patches, with a correlation coefficient of 0.19. In addition, mean annual precipitation and solar radiation had significant (P<0.05) impacts on the effect rate from the edge to the middle circle of desert moss crust patches, with correlation coefficients of 0.17 and 0.20, respectively. Meanwhile, mean annual minimum temperature significantly influenced the edge effect rate of plant stoichiometric characteristics. Our results suggest that desert mosses modulate their stoichiometric characteristics via clustered patch growth, enhancing their environmental adaptability. These findings advance our understanding of how patchiness contributes to moss resilience and clarifies moss growth strategies under changing environments. Thus, this study provides valuable scientific data for predicting the future spatial distribution of desert moss crusts and the stability of desert ecosystems under climate change.

Key words: biological crusts, Syntrichia caninervis, edge effect, stoichiometry, environmental factor