Using expert knowledge and modeling to define mangrove composition, functioning, and threats and estimate time frame for recovery

Abstract

Mangroves are threatened worldwide, and their loss or degradation could impact functioning of the ecosystem. Our aim was to investigate three aspects of mangroves at a global scale: (1) their constituents (2) their indispensable ecological functions, and (3) the maintenance of their constituents and functions in degraded mangroves. We focused on answering two questions: “What is a mangrove ecosystem” and “How vulnerable are mangrove ecosystems to different impacts”? We invited 106 mangrove experts globally to participate in a survey based on the Delphi technique and provide inputs on the three aspects. The outputs from the Delphi technique for the third aspect, i.e. maintenance of constituents and functions were incorporated in a modeling approach to simulate the time frame for recovery. Presented here for the first time are the consensus definition of the mangrove ecosystem and the list of mangrove plant species. In this study, experts considered even monospecific (tree) stands to be a mangrove ecosystem as long as there was adequate tidal exchange, propagule dispersal, and faunal interactions. We provide a ranking of the important ecological functions, faunal groups, and impacts on mangroves. Degradation due to development was identified as having the largest impact on mangroves globally in terms of spatial scale, intensity, and time needed for restoration. The results indicate that mangroves are ecologically unique even though they may be species poor (from the vegetation perspective). The consensus list of mangrove species and the ranking of the mangrove ecological functions could be a useful tool for restoration and management of mangroves. While there is ample literature on the destruction of mangroves due to aquaculture in the past decade, this study clearly shows that more attention must go to avoiding and mitigating mangrove loss due to coastal development (such as building of roads, ports, or harbors).

Community-Based Mangrove Forests Conservation for Sustainable Fisheries

“…Meanwhile, degradation of mangrove forests in Southeast Asia caused by conversion to agriculture and aquaculture (Laulikitnont 2014). The main cause mangrove forests degradation in 10 countries, both in highly developed countries (Australia, Brazil, Mexico and USA) and Less Developed Countries (India, South Africa, Kenya, Kiribati, Indonesia and Sri Lanka) is development (Mukherjee et al 2014).…”

The Delphi technique in ecology and biological conservation: applications and guidelines

“…This is possible in a modified Delphi technique-based approach (Burgman et al 2011b). In addition, the easiest way to improve participant engagement would be to improve the design process and eliminate inadequately formulated questions by (i) defining clear problem objectives, (ii) checking if there is relevant knowledge (for fact-based Delphi process), (iii) identify and remove linguistic ambiguity by piloting the questionnaire with at least two independent experts (as done in the case of Mukherjee et al 2014a). Using parallel forms (e.g.…”

Inter‐ and intraspecific variation in mangrove carbon fraction and wood specific gravity in Gazi Bay, Kenya

“…Mangrove forests are ecologically unique ecosystems that can be found in tropical and subtropical latitudes along the land–sea interface, bays, estuaries, lagoons, and backwaters (Mukherjee et al. ). They provide ecosystem services such as coastal protection, coastal fisheries, land‐building, wood production, nutrient cycling, nursery and breeding protection to marine organisms, and opportunities for ecotourism (Lee et al.…”

“…Despite their role as important carbon sinks and the worldwide efforts to reduce carbon emissions, mangroves are threatened globally by deforestation resulting mainly from aquaculture and agriculture, but also by deforestation's indirect consequences which include drainage and high nutrient levels (Mukherjee et al. , Atwood et al. ).…”