Ecosystem Service Valuations of Mangrove Ecosystems to Inform Decision Making and Future Valuation Exercises

<div><p>The valuation of ecosystem services is a complex process as it includes several dimensions (ecological, socio-cultural and economic) and not all of these can be quantified in monetary units. The aim of this paper is to conduct an ecosystem services valuation study for mangroves ecosystems, the results of which can be used to inform governance and management of mangroves. We used an expert-based participatory approach (the Delphi technique) to identify, categorize and rank the various ecosystem services provided by mangrove ecosystems at a global scale. Subsequently we looked for evidence in the existing ecosystem services literature for monetary valuations of these ecosystem service categories throughout the biogeographic distribution of mangroves. We then compared the relative ranking of ecosystem service categories between the monetary valuations and the expert based analysis. The experts identified 16 ecosystem service categories, six of which are not adequately represented in the literature. There was no significant correlation between the expert based valuation (the Delphi technique) and the economic valuation, indicating that the scope of valuation of ecosystem services needs to be broadened. Acknowledging this diversity in different valuation approaches, and developing methodological frameworks that foster the pluralism of values in ecosystem services research, are crucial for maintaining the credibility of ecosystem services valuation. To conclude, we use the findings of our dual approach to valuation to make recommendations on how to assess and manage the ecosystem services provided by mangrove ecosystems.</p></div

Ecosystem service categories identified by the mangrove Delphi, grouped according to the Common International Classification of Ecosystem Services (CICES) v4.3 (http://cices.eu/).

<p>The first five columns belong to the CICES framework and the results of the Delphi technique are included in the last column.</p><p>Ecosystem service categories identified by the mangrove Delphi, grouped according to the Common International Classification of Ecosystem Services (CICES) v4.3 (<a href="http://cices.eu/" target="_blank">http://cices.eu/</a>).</p

Ranking of the ecosystem service categories of mangroves based on the scores given by the experts in the Delphi technique.

<p>Ranking of the ecosystem service categories of mangroves based on the scores given by the experts in the Delphi technique.</p

Map representing countries (coloured black) where the experts have conducted primary research.

<p>Map representing countries (coloured black) where the experts have conducted primary research.</p

Average economic values (log scale) of the different ecosystem services noted in literature standardized for 2007 Int$/ha*yr.

<p>The five ecosystem services for which no economic values were found, are highlighted in the shaded box.</p

Tree density estimations using plotless sampling in four field sites (30 sampling points, 10 replicates).

<p>Tree density estimation is the mean of 10 estimations using each method with 30 random sampling points; half 95 CI is the half width of the 95% confidence interval for the 10 estimates; NN is Nearest Neighbour; BD is Basic Distance; OD is Ordered Distance; PCQM is Point Centred Quarter Method; VAT is Variable Area Transect.</p

The aggregation indices (R) for the vegetation patterns.

<p>The aggregation indices (R) for the vegetation patterns.</p

Tree density estimations by applying plotless sampling methods to field data.

<p>The density estimations found by applying plotless sampling method to the field data. The field data consisted of mangrove tree locations in four sites. In each graph the horizontal lines are the real tree densities in the sites. The closed squares are the mean of 10 estimations with 30 random sampling points. The verticals crossing the means are the 95% confidence intervals. NN = Nearest Neighbour; BD = Basic Distance; O1 = Ordered distance 1; VY = Variable Area Transect in the y-direction with 3 trees; VX = Variable Area Transect in the x-direction with 3 trees; P1 = Point Centred Quarter Method with the nearest tree in each quadrant.</p

Vegetation patterns.

<p>Spatial point patterns representing 6 possible vegetation distributions (from left to right and from top to bottom): Random, semi-regular, aggregated, random with a density trend, semi-regular with a density trend and aggregated with a density trend.</p

Tree density estimations using plotless sampling within six vegetation patterns (30 sampling points, 10 replicates).

<p>Tree density estimation is the mean of 10 estimations using each method with 30 random sampling points; half 95 CI is the half width of the 95% confidence interval for the 10 estimates; NN is Nearest Neighbour, BD is Basic Distance; OD is Ordered Distance; PCQM is Point Centred Quarter Method; VAT is Variable Area Transect.</p