The natural capital of seagrass beds in the Caribbean: evaluating their ecosystem services and blue carbon trade potential

Abstract

Seagrass beds provide tremendous services to society, including the storage of carbon, with important implications for climate change mitigation. Prioritizing conservation of this valuable natural capital is of global significance, and including seagrass beds in global carbon markets through projects that minimize loss, increase area or restore degraded areas represents a mechanism towards this end. Using newly available Caribbean seagrass distribution data, we estimated carbon storage in the region and calculated economic valuations of total ecosystem services and carbon storage. We estimated the 88 170 km² of seagrass in the Caribbean stores 1337.8 (360.5-2335.0, minimum and maximum estimates, respectively) Tg carbon. The value of these seagrass ecosystems in terms of total ecosystem services and carbon alone was estimated to be $255 billion yr^-1 and $88.3 billion, respectively, highlighting their potential monetary importance for the region. Our results show that Caribbean seagrass beds are globally substantial pools of carbon, and our findings underscore the importance of such evaluation schemes to promote urgently needed conservation of these highly threatened and globally important ecosystems.

Keywords: carbon storage; climate change; ecosystem valuation; emissions trading schemes; seagrass conservation; seagrass distribution.

Figure 1.

(a) Map of seagrass distribution in the Caribbean. (b) Total amount of carbon in seagrass beds of the Caribbean. Bars show amount in teragrams (Tg), with range limits. Y-axis is on a log₁₀ scale.

Figure 2.

(a) Carbon storage in various global pools for comparison with Caribbean seagrass beds. Error bars represent: range limits for Caribbean seagrass beds, range for Mediterranean seagrass beds [30] and global seagrass beds [31], 95% confidence interval for temperate forests [32], and 25% uncertainty for Amazon woody biomass [33]. If present, dots represent mean value. Pg = petagrams. Text values below bars indicate amount of C in Caribbean seagrass relative to each global pool. (b) Monetary value of seagrass bed ecosystem services and C in the Caribbean by country. Purple bars represent value of all seagrass bed ecosystem services per year. Orange bars represent value of carbon stored in seagrass beds calculated based on market value of carbon in California (USA) cap and trade programme.