Abstract

Mangrove deforestation and land subsidence have led to significant challenges such as coastal floods and retreat in northern Java. To address these issues, a large-scale Building with Nature (BwN) solution is being implemented by re-establishing a mangrove forest that acts as a coastal defence. Large semi-permeable bamboo dams are being built to facilitate natural mangrove recruitment by accumulating sediments and creating a habitat for the trees. The ecosystem that grows on these bamboo artificial structures and its effect on the surrounding ecosystem has not yet been fully studied. Within this context, we set up a three-month field experiment in which we looked at the development of a macrofouling community on bamboo poles and mangrove Avicennia marina trees, and the effect of the BwN structure on the development of such communities. We observed that bamboo poles get colonized faster and support a different community than mangrove trunks. Mangrove trees were colonized mostly by Ostreidae whereas bamboo poles by Amphibalanus. Percentage coverage was consistently higher on bamboo poles. Additionally, we observed lower coverage in the location affected by the semi-permeable barrier compared to locations that were not, potentially due to the sediments trapped by the barrier which may impede larval settlement. Lastly, we discuss the idea that the structure and its ecosystem may have a nutrient enrichment effect, potentially influencing mangrove tree resilience to strong winds. Our findings contribute insights into the ecological functions and implications of these BwN structures in the marine environment, emphasizing the importance of considering their broader impacts on mangrove ecosystems.