## 3 Results and Discussion
### Ecological Engineering Interventions and Ecosystem Services  
The Zaalklapsprruit wetland has effectively integrated ecological engineering interventions to restore and enhance its ecosystem services. These interventions, such as the strategic placement of sperm structures to reduce the water velocity and increase the retention time, have improved the water quality and reinstated critical ecosystem functions.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Element** & **Unit** & **S1** & **S2** & **S3** \\ \hline Aluminum (Al\({}_{2}\)O\({}_{3}\)) & (wt \%) & 1.42 & 1.53 & 1.78 \\ \hline Iron (Fe\({}_{2}\)O\({}_{3}\)) & (wt \%) & 1.69 & 1.40 & 1.95 \\ \hline Manganese (MnO) & (wt \%) & 0.10 & 0.10 & 0.08 \\ \hline Sulfur (SO\({}_{3}\)) & (wt \%) & 18.50 & 18.56 & 13.67 \\ \hline \hline \end{tabular} Note: wt \% = weight percentage.  
\end{table}
Table 6: Average concentration of metal and sulfur compounds in precipitated mineral salts for each site.  
Figure 9: Precipitated mineral salts on the dry, unflooded soil surface of the ecologically engineered wetland.  
By stabilizing the pH levels, reducing harmful metal concentrations, and enhancing the wetland's buffering capacity, these measures have facilitated the development of a more resilient and self-sustaining ecosystem.  
The wetland's ability to adopt these engineered solutions demonstrates the synergy between ecological restoration and engineering practices. The reinstatement of ecosystem services, such as improved water quality, habitat provision, and increased biodiversity, highlights the success of these interventions. The reduced metal concentrations, like Al and Fe, and the improved pH levels across the sites illustrate the effectiveness of the engineering measures implemented.  
Additionally, the re-establishment of complex biogeochemical processes and microbial diversity within the wetland further underscores the positive impact of these interventions. For instance, diverse microbial communities, including families like _Helicobacteraceae_, _Xanthomonasaceae_, and _Gallionellaceae_, play a crucial role in transforming and stabilizing metals and sulfur compounds in the sediment.  
Implementing these ecological engineering interventions has contributed to mitigating AMD impacts and promoted the wetland's overall ecological health and resilience. By fostering natural processes and improving water quality, such interventions ensure that wetlands can continue to provide essential ecological services, support biodiversity, and enhance the quality of life for surrounding communities.  
Overall, the Zaalklapspruit wetland is a model for utilizing ecological engineering to restore, regenerate and enhance the functionality of natural ecosystems. The positive outcomes observed in this study highlight the importance of continuing to invest in and apply ecological engineering principles to address environmental challenges and promote the sustainable management of natural resources. Integrating these practices not only aids in the recovery of degraded wetlands but also enhances their capacity to support diverse biological communities and maintain vital ecosystem services.