Background Human activities and reclamation lead to the degradation of Fuzhou East Lake Wetland. The stoichiometric ratios of soil C(carbon), N(nitrogen) and P(phosphorus) not only reflect the cycling process of C, N and P, but also is a predictor of C, N and P saturation limitation. Studying the characteristics of soil C, N, P and their stoichiometric ratios in different habitats is helpful to understanding the limitation of land nutrients and has guiding significance for the rational utilization, protection and restoration of wetland resources in this area.

Methods This study selected the four wetland habitats of bare tidal flat, abandoned breeding pond, Phragmites australis wetland, and shelter forest, five replicates were collected from each habitat, and 0-15 cm of topsoil was collected to measure the contents of soil C, N, and P and their ecological stoichiometry characteristics, as well as the relationship between them and soil physicochemical factors was analyzed.

Results 1) Contents of both soil C and N were basically in the order of shelter forest > P. australis wetland > abandoned breeding pond > bare tidal flat (P < 0.05) whereas soil C and N contents in the shelter forest were 13.99 and 1.47 g/kg. Yet soil P content was basically in the order of shelter forest > abandoned breeding pond > bare tidal flat > P. australis wetland (P < 0.05), while soil P content in the shelter forest was 0.33 g/kg. 2) The regression fitting degree between soil C and N in four wetland habitats was high (R=0.98, P < 0.05). 3) Soil C/N were basically in the order of the P. australis wetland > shelter forest > abandoned breeding pond > bare tidal flat, while C/P and N/P in the soils were significantly (P < 0.05) in the order of P. australis wetland > shelter forest > bare tidal flat > abandoned breeding pond. 4) Soil environmental factors had a certain effect on C, N, P, and their stoichiometric ratios, as there were various correlations between soil C and density (R=-0.45, P < 0.05), soil P and density (R=0.64, P < 0.01), soil P and pH (R=0.67, P < 0.01), soil P and water content (R=-0.73, P < 0.01), soil C/N and density (R=-0.45, P < 0.05), and electrical conductivity (R=-0.52, P < 0.05); soil N/P and water content (R=0.82, P < 0.01), soil N/P and with density (R=-0.88, P < 0.01), and soil N/P and pH (R=-0.66, P < 0.01).

Conclusions Shelter forests regulated the changes of soil C, N, P and their ecological stoichiometric ratios in various wetland habitats, and contributed the most among the four wetland habitats. Our findings are of great significance in shelter forest for clarifying regulating variations of soil C, N, and P, as well as and their ecological stoichiometric ratios in various wetland habitats. This provides a scientific basis for the protection and restoration of key wetland ecosystems.