Eco-friendly structures for sustainable mangrove restoration

Mangrove forests around the world are under significant pressure from climate change (e.g., rising sea levels), and human-related anthropogenic activities (e.g., coastal infrastructure development). Mangrove restoration projects have increased over the past decades but seedling and propagule survival rates are reportedly low, while many projects have failed. There exists a need to assess the effectiveness of sustainable and cost-effective eco-friendly structures (EFS) for advancing the success of mangrove restoration and planting activities. Herein, by EFS, we refer to the frameworks made of biodegradable materials that help overcome establishment bottlenecks and thereby boost seedling survival and growth rates. In this study, we explored the effectiveness of EFS in aiding mangrove restoration success by enhancing seedling establishment and survival and tree growth rates. Furthermore, we examine the steps involved and the challenges limiting EFS implementation in mangrove restoration projects. EFS installed in coastal areas trap sediment and may provide protection for newly planted mangrove seedlings and propagules by providing a stable anchorage and attenuating water flow and waves. Additionally, once plants are established, these biodegradable structures would decompose and add to the soil nutrients stock, thereby improving its fertility and supporting mangrove growth. We emphasize that in sites with favorable biophysical conditions for mangrove growth (hydrology, soil, topography, climate, among others), using EFS can improve mangrove restoration success by enhancing seedling establishment, survival and growth. Mangrove restoration success may have add-on benefits such as increasing the provision of related ecosystem services, blue carbon credit financing and overall coastal environmental sustainability. Given the novelness of this topic in the scientific literature, this article aims to stimulate active discussions, including anticipation of potential challenges (e.g., cost-effectiveness, ability to scale and field limitations in a range of biogeographic settings), for bringing in improvements and scalable adoption strategies to the mangrove restoration approaches under consideration.