## 3 Results and Discussion
### Organic Matter in the Wetland Habitats
This was in accordance with the reports of [PERSON] et al. [46] and [PERSON] et al. [47], who observed the increases in the contents of OC and ON under _Spartima alterniflora_ invasion. On average, in this study, the LFOC, LFON, HFOC, and HFON of invaded habitats were 0.265 g\(\cdot\)kg\({}^{-1}\), 0.029 g\(\cdot\)kg\({}^{-1}\), 5.27 g\(\cdot\)kg\({}^{-1}\), and 0.278 g\(\cdot\)kg\({}^{-1}\) higher than those in normal habitats. [PERSON] et al. [47] showed that _S. alterniflora_ invasion promoted the increase of OC and ON storage for 3.67-4.90 g C\(\cdot\)kg\({}^{-1}\) and 0.307-0.391 g N\(\cdot\)kg\({}^{-1}\), respectively. The increasing level of ON was higher than that in the invaded sediments of this study, while the increase in OC was less than that in our results. Moreover, [PERSON] et al. [48] indicated higher pH values in the invaded soil than in the non-invaded soil and [PERSON] et al. [49] showed a significantly higher depletion of OC in acidic soil (pH \(<\) 5) than in soil with high pH. Therefore, the high accumulation of OC in the invaded areas might profit from the potential high pH values in this study, relative works need to be done to confirm the deduction. Furthermore, the ON storages were also much higher in the invaded habitats than in the normal habitats (Table 2). However, the invasion of _S. alterniflora_ and _Lythrum salicaria_ \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Parameters** & **XRCW** & **NLE** & **XR** & **NL** & \(p\)**-Values** \\ \hline LFOC & 0.771 \(\pm\) 0.28 & 0.834 \(\pm\) 0.41 & 0.460 \(\pm\) 0.24 & 0.601 \(\pm\) 0.04 & 0.173 \\ LFON & 0.043 \(\pm\) 0.021 & 0.042 \(\pm\) 0.024 & 0.022 \(\pm\) 0.014 & 0.025 \(\pm\) 0.005 & 0.182 \\ HFOC & 13.92 \(\pm\) 5.05 & 14.80 \(\pm\) 8.70 & 13.27 \(\pm\) 5.37 & 15.55 \(\pm\) 8.03 & 0.961 \\ HFON & 0.290 \(\pm\) 0.21 & 0.414 \(\pm\) 0.32 & 0.115 \(\pm\) 0.11 & 0.308 \(\pm\) 0.27 & 0.360 \\ S\({}_{\text{(LFOC)}}\) & 0.170 \(\pm\) 0.06 & 0.164 \(\pm\) 0.07 & 0.147 \(\pm\) 0.09 & 0.168 \(\pm\) 0.014 & 0.937 \\ S\({}_{\text{(LFON)}}\) & 0.010 \(\pm\) 0.01 & 0.008 \(\pm\) 0.005 & 0.007 \(\pm\) 0.005 & 0.0068 \(\pm\) 0.003 & 0.798 \\ S\({}_{\text{(HFOC)}}\) & 3.20 \(\pm\) 1.14 & 2.75 \(\pm\) 1.30 & 3.80 \(\pm\) 1.27 & 4.199 \(\pm\) 1.58 & 0.350 \\ S\({}_{\text{(HFON)}}\) & 0.061 \(\pm\) 0.06 & 0.071 \(\pm\) 0.06 & 0.031 \(\pm\) 0.04 & 0.078 \(\pm\) 0.09 & 0.619 \\ Moisture content (\%) & 0.682 \(\pm\) 0.17 & 0.925 \(\pm\) 0.55 & 0.441 \(\pm\) 0.10 & 0.464 \(\pm\) 0.14 & 0.054 \\ Bulk density (g\(\cdot\)cm\({}^{-3}\)) & 0.979 \(\pm\) 0.16 & 0.852 \(\pm\) 0.29 & 1.146 \(\pm\) 0.16 & 1.125 \(\pm\) 0.18 & 0.087 \\ \hline \hline \end{tabular}  
* S\({}_{\text{(LFOC)}}\) means the storage of light fraction organic carbon (LFOC) in wetland sediments of 0–15 cm depth. The \(p\) values indicated the distribution differences among the four wetlands by one-way ANOVA.  
\end{table} 
Table 1: The concentrations (g\(\cdot\)kg\({}^{-1}\)) and storage (kg\(\cdot\)m\({}^{-2}\)) of C and N fractions in the surface sediments of the four wetland areas (mean values \(\pm\) standard deviation). dramatically stimulated N mineralization and nitrification, by adding N input, thus the storage of ON was unchanged [50; 51; 52]. Therefore, this study demonstrated that alligator weed invasion could be beneficial to the net storage of N fractions. It was reported that the deposition of C could be inhibited by a low N content, given that the denitrification process was closely associated with that of OC decomposition [53; 54]. Therefore, an increase of N input was considered favorable for the deposition of OC. The contents of LFOC and LFON were 0.721 and 0.038 g\(\cdot\)kg\({}^{-1}\) in the surface sediments (0-15 cm), significantly higher than they were in the subsurface (15-25 cm), at 0.511 and 0.022 g\(\cdot\)kg\({}^{-1}\) respectively (Figure 2). The accumulation and mineralization of LFs were dynamic and sensitive, and easily affected by climate change, wetland hydrology, and soil physical components [55]. [PERSON] et al. [20] and [PERSON] et al.