<p>Island system is a typical form of habitat fragmentation, which affects plant dispersal through isolation. Although mosses are cryptogams, which reproduce differently from seed plants, they share dispersal-related traits similar to those of seed plants; however, it is unclear whether dispersal-related traits in mosses are affected by isolation effects from habitat fragmentation in the same way as seed plants. We surveyed all the mosses on 168 islands of varying sizes in the Thousand Island Lake region (Zhejiang Province, China) and collected six island attributes for each island. We used two models to test the non-linear thresholds in the island species-area relationship, differentiated the surveyed islands into large and small categories, and examined the patterns of moss dispersal-related traits (seta length and spore size) in response to isolation and other island attributes between large and small islands through RLQ and fourth-corner analysis. We found that isolation was not a significant factor influencing the adaptation of dispersal-related traits for mosses. Rather, increasing canopy closure was associated with longer setae and larger spores. The above phenomena suggest that on larger islands, canopy closure increases humidity and reduces wind, thus promoting setae and spores, while on smaller islands, resource constraints force mosses to make trade-offs in dispersal-related traits. Trait differences observed in moss communities in fragmented habitats provide a new perspective on moss-specific dispersal abilities.</p>