Carbon Budget as a Tool for Assessing Mangrove Forests Degradation in the Western, Coastal Wetlands Complex (Ramsar Site 1017) of Southern Benin, West Africa - The Land/Ocean Interactions in the Coastal Zone of West and Central Africa - page 139

Table 1 Selected sites for mangrove permanent plot establishment

Site GPS fixes Type of plot Vegetation condition

No Name N E

0625,945 0 00155,557 0

1 Kpétou Blank area where mangrove

stands do not exist in the
natural state

Area in Kpétou village (Agatogbo) on the shores of Lake
Ahémé. This area is periodically flooded by tides and also
influenced through communication of the lake with the
Atlantic sea through the Mono River. Presence of pockets
of mangroves (Rizophora racemosa and A. germinans).
The dominant plants are grasses (P. vaginatum). Site for
mangrove reforestation efforts of the NGO Eco-Benin.
Heavy fishing by dugout canoes along the banks of the
lake

2 Djègbadji 0619,901 0

00205,034 0 Very disturbed mangroves Situated within the Djègbadji village in Ouidah town is a

branch of the coastal lagoon, periodically flooded and
tidally influenced through communication with the
seawater. Presence of mangrove species as Rizophora
racemosa and A. germinans scattered in the various
islands and shores. Also presence of sea grasses (P.
vaginatum) lining the floor. Mangroves in this area are
highly disturbed by human activities, especially women
who collect wood to prepare salt, high activity in this
area, but also for firewood. Floods also disrupt natural
regeneration

0621,164 0 00216,998 0

3 Adounko Medium mangrove

degradation

Area in Adounko village in the coastal lagoon. It is the part
of the Marine Protected Area that the Benin Agency for
the Environment is setting up of about (54 ha) area
periodically flooded by tides and influenced through
communication with the seawater. Presence of
mangroves (R. racemosa and A. germinans) scattered on
the shore. Also presence of grasses (P. vaginatum) and
Acrosticum and also other species that are at the interface
between the land and sea mangrove zone. Area also
disturbed by human activities, especially women who
collect firewood and other food plants

Adounko 6 21,056 0 00217,456 0 4 Non-degraded mangroves Area in the Adounko village near Togbin town within the

coastal lagoon periodically flooded by tides and
influenced through communication with the seawater.
Presence of large stands of mangroves (R. racemosa and
A. germinans). Presence of other species that are at the
interface between land and sea. The mangrove zone is
protected by the state because it is the part of the Marine
Protected Area that the Benin Agency for the
Environment is currently implementing. It is also sacred
forest with spiritual worship of some deities

contributing most to emissions when mangroves are
degraded. Soil cores were extracted from each of the
20 9 10 m plots using a core of 5.0 cm diameter and sys-
tematically divided into different depth intervals (0-15,
15-30, 30-50, and 50-100 cm), following the protocol
recommended by Kauffman and Donato ( 2012 ). A sample
of 5 cm length was extracted from the central portion of
each depth interval to obtain a standard volume for all
subsamples (Fig. 5 ).
A total of 48 soil samples were collected and placed in
pre-labeled plastic bags. In the laboratory (Laboratory of
Soil Science, Water and Environment of the Centre for
Agricultural Research Agonkanme'-Benin.), samples were

weighed and oven-dried to constant mass at 70 C for 48 h
to obtain wet: dry ratios (Kauffman and Donato 2012 ). Bulk
density was calculated as follows:

¼ Oven dry sample mass

ðÞ

Soil bulk density gm 3

Sample volume ð m 3 Þ

ð 1 Þ

where volume = cross-sectional area of the corer 9 the
height of the sample subsection.
Of the dried soil samples, 5-10 g subsamples were
weighed out into crucibles and set in a muffle furnace for
combustion at 550 C for 8 h through the process of loss on