Environmental Engineering Reference
In-Depth Information
Fig. 7
Distribution of annual
carbon stock in different
mangrove sites in southern Benin
Above ground carbon density
Below ground carbon density
50
0
-50
-100
-150
-200
-250
-300
Site 1: Kpétou
-Non wooded
Site 2: Djegbadji -
More degraded
mangroves
Site 3: Adounko -
Less degraded
mangrove
Site 4: Adounko -
Non degraded
mangroves
925.4 t/ha (85 % underground component) in degraded
mangrove and 1,520 t/ha (35.1 %air component) for non-
degraded mangroves (Ajonina et al.
2013
). This difference
could be due to variability in climatic and environmental
conditions, especially temperature, amount of rainfall and
its distribution, and solar radiation in the western part of
Africa compared to the central. It was recognized that the
carbon fluxes which are exchanged by the terrestrial eco-
systems with the atmosphere in Africa are found to be
strongly dependent on water availability, temperature, and
solar radiation (Merlbold et al.
2009
; Williams et al.
2008
;
Kutsch et al.
2008
; Hanan et al.
1998
). Potential net CO
2
e
emissions from up to 30 cm soil depth (compared to non-
wooded mangrove vegetation) are expected to increase
from 10.28 to 99.64 t CO
2
e/ha (22 % of non-wooded
mangroves) following mangrove degradation and 43 t
CO
2
e/ha (10 % of non-wooded mangroves) avoided CO
2
e
emissions from undisturbed mangrove forests (Table
3
).The
values tend to fall within the interval recorded elsewhere:
For example, Lovelock et al. (
2011
) found 2,900 t CO
2
/
km
2
/year (29.0 t/ha/year) emissions from degraded man-
groves in Belize, Cahoon et al. (
2003
) found 1,500 t CO
2
/
km
2
/year (15.0 t/ha/year) emissions from degraded man-
groves in Honduras, and Burford and Longmore (
2001
)
found
Conclusion
The assessment of carbon stocks in mangrove wetlands of the
West Complex of southern Benin (Ramsar site 1017), using
standard methods, presents a typical distribution between
above- and belowground components similar to other man-
grove ecosystems of the world. However, the carbon stocks
are much lower than those in the Central Africa region. In
future, it appears very important to continue to monitor the
carbon stock of all mangrove ecosystems inventoried to
better define strategies to diminish carbon emissions.
Acknowledgments This study has been prepared with the financial
assistance of the IUCN National Committee of the Netherlands,
Wetlands International and Both Ends, partners in the Ecosystem
Alliance. The authors would like to thank all individuals and institu-
tions that have contributed to the realization of this work. We also
express gratitude to the leaders and authorities in the villages in which
the sites were surveyed for their hospitality and especially to field
assistants from the different site inventoried, as well as partners
involved in laboratory analysis and particularly the officials of the
Laboratory of Soil Science, Water and Environment of the National
Institute of Agricultural Research of Benin (INRAB) and those who
took part in the workshop to discuss the preliminary results of this
study. The administrative staff of NGO ECO-BENIN is heartily
thanked for their sense of hospitality and work beyond working hours
during the study period.
CO
2
/km
2
/year
1,750 t
(17.5 t/ha/year)
emissions
from degraded mangroves in Australia.
References
Adame MF, Kauffman JB, Medina I, Gamboa JN, Torres O, Caamal
JP, Reza M, Herrera-Silveira JA (2013) Carbon stocks of tropical
coastal wetlands within the karstic landscape of the Mexican
Caribbean.
Different Allometric Relations and Coefficient
Values Obtained at the Site
PLoS
ONE
8(2):e56569.
Ajonina G (2011) Rapid assessment of mangrove status and conditions
for use to assess potential for marine payment for ecosystem
services in Amanzuri and surrounding areas in the western coastal
region of Ghana, West Africa. In: The Marine Ecosystem Services
(MARES) Programme, Forest Trends Report, 37 p
V ¼ 0
:
000103 D
2
:
6207
R
2
¼ 0
:
976 n ¼ 233
ð
7
Þ
y ¼ 0
:
112 D
2
H
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6
:
462 R
2
¼ 0
:
795 n ¼ 52
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