Restored wetlands show rapid vegetation recovery and substantial surface-water expansion

Ecological restoration is essential for improving the ecological integrity of degraded ecosystems to enhance ecosystem services and biodiversity. In this study, we assessed the effectiveness of wetland restoration on retired cranberry farms by analyzing vegetation recovery and surface-water dynamics using the enhanced vegetation index (EVI) and normalized difference water index (NDWI) derived from Sentinel-2 satellite imagery. To quantify temporal dynamics of both vegetation recovery and surface-water cover, we identified the spectral distinctions among restored wetland plant communities. Our results indicated the emergence of distinct plant communities upon restoration. Restored wetlands in general showed significant and progressive vegetation recovery and expanding surface-water cover with clear spectral differentiation among plant communities, as indicated by improved EVI and NDWI estimates. Wetlands restored in 2016 showed higher EVI estimates compared to both reference wetlands and those restored in 2020, suggesting more advanced vegetation recovery. Wetlands restored in 2020 displayed greater variability in EVI, particularly for open-water wetlands, with less consistent patterns compared to the 2016 restorations. Reference wetlands consistently exhibited the highest NDWI values, indicating that restored wetlands have not yet achieved full hydrological saturation. Notably, wetlands restored in 2020 had significantly greater surface-water coverage than those restored in 2016. Our study suggests that restored wetlands have gained remarkable progress in vegetation recovery, although they are yet to reach the desired state of hydrological saturation compared to reference wetlands. By providing insights into the ecological trajectories of restored wetlands, our study supports evidence-based management practices for fostering sustainable wetland ecosystems.

Implications for Practice

• Computing spectral indices from open-access satellite imagery offers an efficient, scalable, and cost-effective approach for assessing restoration outcomes, reducing dependence on labor-intensive field surveys.
• Distinct recovery trajectories observed among wetland plant communities emphasize the need for tailored restoration strategies that account for site-specific ecological and hydrological conditions.
• While vegetation recovers rapidly, restored wetlands often lag in achieving hydrological equivalence to reference wetlands, underscoring the need for adaptive management approaches that enhance hydrological connectivity to ensure long-term success.
• Variations in vegetation and hydrologic responses underscore the role of time in achieving ecosystem stability, reinforcing the importance of continued monitoring for decision-making.
• Spectral index analysis offers a replicable framework for monitoring restored wetlands and improving restoration outcomes.