Spatiotemporal Dynamics of Plant-Soil-Enzyme Interactions in Intertidal Wetlands

To investigate the spatiotemporal dynamics of plant communities in intertidal wetland during exposure periods, an in situ experiment with a two-factor repeated measures experimental design was conducted in Shengjin Lake, China. We hypothesized that exposure duration would significantly affect plant community characteristics and associated soil properties. During the exposure period, 10 transects were established, with three quadrats evenly arranged at fixed intervals along each transect. Plant community characteristics, including species composition, coverage, and mean height, were measured repeatedly at early, mid, and late stages. Concurrently, soil samples were collected from the 0-20 cm layer to determine soil physicochemical properties and enzyme activities. Plant community composition differed significantly across both temporal (Global R = 0.728, p < 0.01) and spatial (Global R = 0.475, p < 0.01) gradients. With increasing exposure duration, ACP activity increased gradually, whereas TP showed an initial increase, followed by a decline. In contrast, EC, NH₄ ⁺-N, NO₃ ^--N, AK, TK, CAT, ALP, and UE decreased progressively. WC, pH, SOM, TN, AN, AP, and SC exhibited relatively minor variation. Redundancy analysis identified exposure duration as the dominant driver of plant community variation, followed by ALP, NO₃ ^--N, and pH. These results indicate that prolonged exposure enhances plant species diversity while modifying specific soil nutrient pools and enzyme activities. The coordinated temporal responses of soil nutrients and enzymes suggest an adaptive adjustment of the plant-soil-enzyme system to hydrological dynamics in intertidal wetlands.