Abstract:

Due to traditional forest management, many forest ecosystems in western Sichuan Province have become degraded. To quantify the composition and structure of bryophyte communities which are early in the natural recovery process, we sampled four sites with similar topographic situation, but at different points in the recovery process. All sites were located in the Rangtang County, Aba region, Sichuan Province. Species composition and structural parameters were surveyed between July and October of 2006. We used ANOVA analysis to detect differences among bryophyte communities, and nonparametric Spearman correlation to test for relationships between bryophyte structural parameters and environmental factors. We used regression analysis to explore the factors influencing bryophyte development. Our results suggested three main points. Firstly, dominant species composition changed during the natural recovery process. Some small-sized, heliophilous, and disturbance-resistant acrocarpous mosses with a high sporulation ability had expanded their populations, while some hygrophilous pleurocarpous mosses sensitive to early successional conditions had disappeared. Secondly, diversity indices, coverage, and biomass decreased during the natural recovery process, indicating that bryophyte communities became simplified with recovery progress. Thirdly, there was a close relationship between vascular plants and bryophytes. Bryophyte cover and richness were mainly influenced by herbaceous layer biomass, while bryophyte biomass was significantly affected by herbaceous layer height. Our results implied that different microhabitats resulting from vascular plant community development affected development of bryophyte communities.

Key words: forestry management, biodiversity conservation, development of bryophyte, vascular plant