We use cookies to improve your experience with our site. | More info.

Nature Geoscience | Letter

Mangroves among the most carbon-rich forests in the tropics

Journal name:
Nature Geoscience
Volume:
4,
Pages:
293–297
Year published:
DOI:
doi:10.1038/ngeo1123
Received
Accepted
Published online

Mangrove forests occur along ocean coastlines throughout the tropics, and support numerous ecosystem services, including fisheries production and nutrient cycling. However, the areal extent of mangrove forests has declined by 30–50% over the past half century as a result of coastal development, aquaculture expansion and over-harvesting1, 2, 3, 4. Carbon emissions resulting from mangrove loss are uncertain, owing in part to a lack of broad-scale data on the amount of carbon stored in these ecosystems, particularly below ground5. Here, we quantified whole-ecosystem carbon storage by measuring tree and dead wood biomass, soil carbon content, and soil depth in 25 mangrove forests across a broad area of the Indo-Pacific region—spanning 30° of latitude and 73° of longitude—where mangrove area and diversity are greatest4, 6. These data indicate that mangroves are among the most carbon-rich forests in the tropics, containing on average 1,023 Mg carbon per hectare. Organic-rich soils ranged from 0.5 m to more than 3 m in depth and accounted for 49–98% of carbon storage in these systems. Combining our data with other published information, we estimate that mangrove deforestation generates emissions of 0.02–0.12 Pg carbon per year—as much as around 10% of emissions from deforestation globally, despite accounting for just 0.7% of tropical forest area6, 7.

View full text

Subject terms:

At a glance

Figures

View all figures
  1. Examples of Indo-Pacific mangroves.
    Figure 1: Examples of Indo-Pacific mangroves.

    The sample included a broad range of stand stature, composition, and soil depth. a, Exemplary large-stature, high-density mangrove dominated by Bruguiera, Borneo, Indonesia (canopy height >15 m, canopy closure >90%, soil depth >3 m). b, Exemplary small-stature, low-density mangrove dominated by Rhizophora, Sulawesi, Indonesia (canopy height <4 m, canopy closure <60%, soil depth 0.35–0.78 m). Both estuarine and oceanic mangroves can exhibit both conditions (see Supplementary Table S1).

  2. Comparison of mangrove C storage (mean [plusmn]95% confidence interval) with that of major global forest domains.
    Figure 2: Comparison of mangrove C storage (mean ±95% confidence interval) with that of major global forest domains.

    Mean C storage by domain was derived from ref. 9, including default values for tree, litter, dead wood, root:shoot ratios, and soils, with the assumption that the top 30 cm of soil contains 50% of all C residing in soil9, except for boreal forests (25%). Domain means are presented for context; however some forest types within each contain substantially higher or lower C stores9, 10. In general, the top 30 cm of soil C are considered the most vulnerable to land-use change9; however in suboxic peat/muck soils, drainage, excavation, and oxidation may influence deeper layers29.

  3. Above- and below-ground C pools in Indo-Pacific mangroves, assessed by distance from the seaward edge.
    Figure 3: Above- and below-ground C pools in Indo-Pacific mangroves, assessed by distance from the seaward edge.

    a, Estuarine mangroves situated on large alluvial deltas. b, Oceanic mangroves situated in marine edge environments—for example, island coasts. Below-ground C comprised 71–98% and 49–90% of ecosystem C in estuarine and oceanic sites, respectively. Overall carbon storage did not vary significantly with distance from the seaward edge in either setting over the range sampled (P>0.10 for above-ground, below-ground, and total C storage by functional data analysis (FDA, see Methods); 95% CIs for rates-of-change all overlapped zero and were between −1.2 and 3.9 Mg C ha−1 per metre of distance from edge).

  4. Soil properties determining below-ground carbon storage in Indo-Pacific mangroves.
    Figure 4: Soil properties determining below-ground carbon storage in Indo-Pacific mangroves.

    a, Soil C concentration was greater in oceanic (mean=14.6%) versus estuarine (mean=7.9%) sites (P=0.001), and decreased with depth (P<0.0001; effect stronger in oceanic sites). Change in C concentration with seaward distance was biologically insignificant. b, Soil bulk density did not differ significantly with setting (P=0.79); hence one line is shown combining both settings. Bulk density increased with depth (P<0.0001) but not seaward distance (P=0.20 ), and a distance*depth interaction term was not significant (P=0.47). c, Soil depth increased with distance from the seaward edge in oceanic stands (FDA result: P=0.002, 95% CI for rate-of-change = 21–65 cm increase per 100 m distance).

References

  1. Duke, N. C. et al. A world without mangroves? Science 317, 41–42 (2007).
  2. Polidoro, B. A. et al. The loss of species: Mangrove extinction risk and geographic areas of global concern. PLoS ONE 5, e10095 (2010).
  3. Alongi, D. M. Present state and future of the world’s mangrove forests. Environ. Conserv. 29, 331–349 (2002).
  4. Food and Agriculture Organization of the United Nations (FAO). The World’s Mangroves 1980–2005 (FAO Forestry Paper 153. FAO, 2007).
  5. Bouillon, S., Rivera-Monroy, V. H., Twilley, R. R., Kairo, J. G. & Mangroves, in The Management of Natural Coastal Carbon Sinks (eds Laffoley, D. & Grimsditch) (IUCN, 2009).
  6. Giri, C. et al. Status and distribution of mangrove forests of the world using earth observation satellite data. Glob. Ecol. Biogeogr. 20, 154–159 (2011).
  7. van der Werf, G. R. et al. CO2 emissions from forest loss. Nature Geosci. 2, 737–738 (2009).
  8. IPCC in The Fourth Assessment Report Climate Change 2007 (eds Pachauri, R. K. & Reisinger, A.) (IPCC, 2007).
  9. Intergovernmental Panel on Climate Change (IPCC) in Good Practice Guidance for Land use, Land-use Change, and Forestry (eds Penman, J. et al.) (Institute for Global Environmental Strategies, 2003).
  10. Keith, H., Mackey, B. G. & Lindenmayer, D. B. Re-evaluation of forest biomass carbon stocks and lessons from the world’s most carbon-dense forests. Proc. Natl Acad. Sci. USA 106, 11635–11640 (2009).
  11. Page, S. E. et al. The amount of carbon released from peat and forest fires in Indonesia during 1997. Nature 420, 61–65 (2002).
  12. Page, S. E., Rieley, J. O. & Banks, C. J. Global and regional importance of the tropical peatland carbon pool. Glob. Change Biol. 17, 798–818 (2011).
  13. Murdiyarso, D. M., Hergoualc’h, K. & Verchot, L. V. Opportunities for reducing greenhouse gas emissions in tropical peatlands. Proc. Natl Acad. Sci. USA 107, 19655–19660 (2010).
  14. Gilman, E. L., Ellison, J., Duke, N. C. & Field, C. Threats to mangroves from climate change and adaptation options. Aquat. Bot. 89, 237–250 (2008).
  15. Alongi, D. M. Mangrove forests: Resilience, protection from tsunamis, and responses to global climate change. Estuar. Coast Shelf Sci. 76, 1–13 (2008).
  16. Kristensen, E., Bouillon, S., Dittmar, T. & Marchand, C. Organic carbon dynamics in mangrove ecosystems. Aquat. Bot. 89, 201–219 (2008).
  17. Komiyama, A., Ong, J. E. & Poungparn, S. Allometry, biomass, and productivity of mangrove forests. Aquat. Bot. 89, 128–137 (2008).
  18. Twilley, R. R., Chen, R. H. & Hargis, T. Carbon sinks in mangroves and their implications to carbon budget of tropical coastal ecosystems. Water Air Soil Pollut. 64, 265–288 (1992).
  19. Bouillon, S. et al. Mangrove production and carbon sinks: A revision of global budget estimates. Glob. Biogeochem. Cycles 22, GB2013 (2008).
  20. Alongi, D. M. et al. Sediment accumulation and organic material flux in a managed mangrove ecosystem: Estimates of land–ocean–atmosphere exchange in peninsular Malaysia. Mar. Geol. 208, 383–402 (2004).
  21. Chmura, G. L., Anisfeld, S. C., Cahoon, D. R. & Lynch, J. C. Global carbon sequestration in tidal, saline wetland soils. Glob. Biogeochem. Cycles 17, 1111 (2003).
  22. Eong, O. J. Mangroves—a carbon source and sink. Chemosphere 27, 1097–1107 (1993).
  23. Golley, F., Odum, H. T. & Wilson, R. F. The structure and metabolism of a Puerto Rican red mangrove forest in May. Ecology 43, 9–19 (1962).
  24. Fujimoto, K. et al. Belowground carbon storage of Micronesian mangrove forests. Ecol. Res. 14, 409–413 (1999).
  25. Matsui, N. Estimated stocks of organic carbon in mangrove roots and sediments in Hinchinbrook Channel, Australia. Mangr. Salt Marsh. 2, 199–204 (1998).
  26. Sjöling, S., Mohammed, S. M., Lyimo, T. J. & Kyaruzi, J. J. Benthic bacterial diversity and nutrient processes in mangroves: Impact of deforestation. Estuar. Coast Shelf Sci. 63, 397–406 (2005).
  27. Strangmann, A., Bashan, Y. & Giani, L. Methane in pristine and impaired mangrove soils and its possible effects on establishment of mangrove seedlings. Biol. Fertil. Soils 44, 511–519 (2008).
  28. Granek, E. & Ruttenberg, B. I. Changes in biotic and abiotic processes following mangrove clearing. Estuar. Coast Shelf Sci. 80, 555–562 (2008).
  29. Hooijer, A., Silvius, M., Wösten, H. & Page, S. PEAT-CO2: Assessment of CO2 Emissions from Drained Peatlands in SE Asia. Delft Hydraulics Report Q3943 (2006).
  30. Church, J. A. et al. Understanding global sea levels: Past, present and future. Sustain. Sci. 3, 9–22 (2008).

Download references

Author information

Affiliations

  1. USDA Forest Service, Pacific Southwest Research Station, 60 Nowelo St., Hilo, Hawaii 96720, USA

    • Daniel C. Donato

  2. USDA Forest Service, Northern Research Station, 271 Mast Rd., Durham, New Hampshire 03824, USA

    • J. Boone Kauffman

  3. Center for International Forestry Research (CIFOR), PO Box 0113 BOCBD, Bogor 16000, Indonesia

    • Daniel Murdiyarso &
    • Sofyan Kurnianto

  4. USDA Forest Service, International Programs, 1099 14th street NW, Suite 5500W, Washington, District of Columbia 20005, USA

    • Melanie Stidham

  5. Viikki Tropical Resources Institute (VITRI), University of Helsinki, PO Box 27, FIN-00014, Finland

    • Markku Kanninen

Contributions

D.C.D. co-designed the study, collected field data, performed data analyses, and led the writing of the paper. J.B.K. conceived and co-designed the study, and contributed to data collection and writing. D.M. co-conceived the study, arranged for and contributed to data collection, and contributed to writing. S.K. contributed to data collection, data analysis, and writing. M.S. collected field data and contributed to writing. M.K. co-conceived the study and contributed to writing.

Competing financial interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to:

Author details

Supplementary information

PDF files

  1. Supplementary Information (400KB)

    Supplementary Information

Additional data