Mangrove restoration in Colombia: Trends and lessons learned

Loss and degradation of mangroves in Colombia has motivated the development of restoration efforts since the 1990s. Many experiences have been accumulated; however, there is no general balance to evaluate approaches, techniques, and results from which best practices and public policy, and a long-term national mangrove restoration plan can be proposed. To fill this gap, a review of the scientific literature and unpublished reports was complemented with surveys to build a database "MANRESCO v. 1.0" released with paper. Analysis made it possible to describe the historical and geographical trends and to identify the relative success of the many actions, according to restoration types, mangroves types and specific techniques we documented. 163 actions between 1995 and 2018 on six biophysical typologies of mangroves, four restoration types and ten techniques to face deforestation, hydrological alteration, and oil spills were recorded. A Chi-square test was used to found relationship between relative succeed and some variables. No relationship was found between biophysical mangrove types and the relative success (p-value = 0.11), but success largely depended on the type of restoration and the technique used. Most effective type of restoration was the Community Based Ecological Mangrove Restoration. Techniques involving hydrological restoration had more highly successful cases than others (15%). The most widely used and common technique was the sowing of seedlings and propagules, which have been commonly used regardless of anthropic threat, but with a low level of success. According to the results of the largest mangrove restoration program in Latin America (Ciénaga Grande de Santa Marta), the techniques can be complemented in scale and time, resulting in a 69% of mangrove cover at a cost of 4115US $/ha. However, techniques need to be chosen on proper knowledge of socioecological systems to improve the cost-benefit estimation. Lesson learned and gaps identified can be useful to other countries carrying on mangrove restoration programs.