Indonesia's seagrass, scored: 21 meadows, 0.39 to 0.88, and no carbon in the index

Read the indicator list and you can see what this index buys. Species richness, seagrass cover, water clarity, macroalgae cover and epiphyte cover describe the plants and the water above them ^[5]. None of the five is a measurement of carbon in sediment or biomass ^[20]. A program that uses the Seagrass Ecological Quality Index to pick meadows is therefore selecting on condition and assuming the carbon follows, in work the authors position as strengthening seagrass as a blue carbon reservoir ^[15]. That is a defensible way to decide where to send a survey crew. It is not a tonnage, and it will not price a credit.

The spread is what makes the ranking useful at all. Scores across the 21 sites run from 0.39 to 0.88 ^[6], a range of 0.49 points ^[17] with the best site scoring 2.3 times the worst ^[16]. Lae-Lae sits at the bottom on low cover, low richness and poor water clarity ^[8]; Pasi-Gusung, Parak and Maharayya are at the top ^[7]. A coastline-level average would sit in the middle of that and describe none of them.

The categories, though, are relative to the neighbours. A hotspot in this framework is a healthy site whose surrounding area is also healthy ^[9], and an outlier is a site that contrasts with what is around it ^[11]. By construction, a meadow's label depends on which nearby sites were sampled and how far the survey extended. Bone Batang and Barrang Lompo are called potentially vulnerable refugia precisely because their surroundings score worse ^[11], while Lae-Lae and Bonto Bahari are degraded patches inside healthier systems and so read as restoration candidates ^[12]. Add or drop neighbours and those readings can move.

One entry in the coldspot list deserves attention from anyone planning to pay for restoration: Badi-Alami and Badi-Restorasi both land there ^[10]. Whatever separates those two sites, the index does not yet separate them.

Count the named sites and 14 of the 21 are accounted for across the three categories, leaving seven unassigned in the published account ^[18]. The degraded clusters also outnumber the healthy ones, six coldspots to four hotspots ^[19]. For a country holding more than 660,000 hectares of seagrass ^[4], that is a thin and lopsided base to allocate from, which is consistent with the problem the team set out to work around: condition assessment is hard where long-term monitoring is sparse ^[13]. Rohani Ambo-Rappe's group at Hasanuddin University built the framework for that data-poor case ^[2], and the paper in Science of The Total Environment argues the point that follows from the mosaic, that a single national policy setting cannot fit it ^[14][3].

The honest use of a SEQI map is as a sampling plan. It tells you which four meadows to defend, which six to survey for pressure sources, and which two isolated healthy patches would lose the most if the neighbourhood keeps declining.