Abstract
Mangrove forests provide critical ecosystem services including carbon sequestration, shoreline stabilization, and habitats for numerous flora and fauna. However, disturbances such as hurricanes influence forest structure, coarse woody debris (CWD) accumulation, and seedling recruitment. This study evaluates the effectiveness of using a viDoc RTK rover system compared to traditional methods in assessing CWD volumes and seedling and pneumatophore densities in a Southwest Florida mangrove forest recovering from hurricane damage. Additionally, this research investigated whether seedling recruitment was influenced by elevation, CWD, distance to shore and LAI. Data was collected from 30 randomly selected subplots within a 1-ha long term mangrove forest plot using traditional field methods and LiDAR-based approaches with a viDoc RTK Rover and processed using Pix4Dmatic, and CloudCompare. Results indicate that inland plots had higher average CWD volumes than nearshore plots, though the relationship between CWD volume and distance to shore was weak (p=0.07). A Poisson LASSO Generalized Linear Model revealed that elevation, CWD volume, leaf area index and distance to shore were all significant predictors of seedling density (p<0.0001). While CWD was not the strongest individual predictor, its significance alongside elevation suggests it plays a meaningful role in mangrove regeneration. Manual and LiDAR-derived measurements of CWD volume were strongly correlated and did not differ significantly from a 1:1 relationship (p=0.0001). This analysis suggested there was no difference between the two methods of measuring CWD. However, areas with dense canopies, shadows, and high-water levels reduced the quality of the point clouds and limited the detection of certain structures in processed scans. Overall, these findings highlight the role of CWD in mangrove recovery, particularly as microsites for seedling establishment, and emphasize the importance of elevation and species interactions. This study also supports the application of LiDAR for mangrove monitoring, with ground validation remaining necessary to refine accuracy of data collected because it reduces disturbance to the system, provides a repository of photos and data, and provides a rapid assessment technique with reduced field sampling time. By understanding the factors that influence post-hurricane recovery, conservation strategies and restoration activities can be better developed to enhance the recovery of mangrove ecosystems in cyclone-impacted regions.
