Quantification of the spatial distribution of individual mangrove tree species derived from LiDAR point clouds

Abstract

Mangrove forests have unquestionably high environmental and ecological value. Mangrove trees are believed to have habitat zonation that is controlled mainly by the relative sea level. However, earlier discussions of mangrove habitats have remained limited in terms of their quality and quantity because of a lack of high-resolution spatial information of microtopography and trees. To clarify mangrove habitability over a wide forest area, we compounded mobile laser scanning (MLS) and aerial laser scanning (ALS) LiDAR dataset of the Miyara River mangrove on Ishigaki Island, Okinawa, Japan. The MLS provided sub-canopy data, while the unmanned aerial vehicle ALS data mainly provided a point cloud of the canopy. We corrected point clouds and combined these data. The results indicated that ALS is unable to reconstruct the microtopography of the dense mangrove area well. Moreover, tree species were not identifiable from the ALS data. However, by applying MLS to the mangrove forest, we obtained high-resolution microtopography and tree information inside the forest, although the measurement area was limited to comparison with ALS. By combining ALS and MLS point clouds, 3D point clouds of the forest were well reconstructed. From these point clouds, a high-resolution digital elevation model was created. Subsequently, we segmented trees individually from composite MLS point clouds and identified each tree species. Consequently, the spatial distribution of thousands of mangrove trees was reconstructed at the Miyara River mouth. The spatial distribution of mangrove tree species together with earlier aerial photographs suggests that mangrove species have been segregated in accordance with changes in their elevation and environment over 40 years. Our findings suggest that the distribution of the species changed sensitively along with dynamic variation of the microtopography.

The Role of the Community in the Development of Mangrove Forest Ecotourism in Pasar Banggi, Rembang Regency

“…In Asia, mangrove forests span 7,441,000 hectares, while in Africa they reach 3,258,000 hectares, and in the Americas they reach 5,831,000 hectares. Indonesia alone has a significant contribution to the global mangrove forest area, accounting for almost 50% of the total mangrove area in the Asian continent, and almost 25% of the total mangrove forest area worldwide (Kasai et al, 2024;Onrizal, 2010;Polidoro et al, 2010;Saintilan et al, 2014). The distribution of mangrove forests in Indonesia shows significant variation, with most of the area found in Papua, accounting for 69.43% of the total mangrove forest area in the country (Arifanti et al, 2022;Ilman et al, 2016;Karimah, 2017;Rizal, 2018).…”