Environmental Engineering Reference
In-Depth Information
Table 1
Total annual litterfall (g/m
2
)
Mangrove forest stand composition
Total annual production (g/m
2
)
Mean monthly production (g/m
2
)
Litter
component
E CV
Avicennia
Flowers
76
6.3
0.7
37.7
Fruits/seeds
80
6.7
0.8
40.7
Leaves
1,097
91.4
20.3
77.1
Twigs
86
7.2
1.0
46.7
Total
1,339
111.6
21.3
66.2
Rhizophora
Flowers
75
6.2
0.8
45.8
Fruits/seeds
67
5.5
1.2
74.8
Leaves
1,685
140.4
12.8
31.6
Twigs
99
8.2
1.1
46.1
Total
1,926
16.5
14.7
31.8
Mixed
Flowers
80
6.7
0.5
24.7
Fruits/seeds
100
8.3
2.5
102.9
Leaves
1,826
152.2
20.0
45.4
Twigs
138
11.5
3.2
94.8
Total
2,145
178.8
21.5
41.7
Avicennia
Flowers
12
1.0
0.6
213.9
Fruits/seeds
28
2.3
0.8
117.8
Leaves
718
59.8
14.4
83.2
Twigs
77
6.4
1.1
60.4
Total
834
69.5
14.4
71.8
Rhizophora
Flowers
238
19.8
4.2
72.6
Fruits/seeds
99
8.3
2.9
123.0
Leaves
1,119
93.3
19.7
73.0
Twigs
20
1.7
0.5
112.7
Total
1,477
123.1
27.0
76.1
Mixed
Flowers
28
2.3
0.3
44.5
Fruits/seeds
16
1.3
0.5
129.2
Leaves
630
52.5
12.6
83.1
Twigs
50
4.1
1.2
98.3
Total
724
60.3
12.4
71.0
(81.28 %) (Table
1
). For Cameroon sites, the total annual
litterfall was 5,410 g/m
2
/year or 54.1 t/ha (average value:
4.5 t/ha) made up by Avicennia (24.75 %), Rhizophora
(35.60 %) and mixed (39.64 %) (Fig.
14
). Leaf litterfall
comprised the largest component (85.17 %) (Table
1
). It is
apparent from Figs.
12
,
13
and
14
that the total litterfall of
those two countries within the West and Central African
ecoregion was 8,445 g/m
2
/year or 84.4 t/ha (average value:
7 t/ha), with a high percentage of leaf litterfall (83.77 %).
Litterfall values for mangrove forests worldwide range
from 2 to 16 t/ha/year (Day and Machado
1986
; Spalding
et al.
2010
); thus the values of litterfall from the mangrove
sites of Ghana (average annual production: 2.5 t/ha/year)
and those of Cameroon (average annual production: 4.5 t/ha/
year), actually fall below the minimum of this range and are
a little bit higher than those of a riverine mangrove wetland
(1.7 t/ha/year) reported by Arreola-Lizárraga et al. (
2004
).
Pattern of Total Monthly Litterfall
Figure
14
show that the total value of mangrove leaves in
Cameroon was higher than that in Ghana. However, the
response to environmental conditions was similar in both
countries, since all tend to shed more litter during dry
season than during the rainy season (Conchedda et al.
2011
). Although data were not presented, it was appeared
that low values of total leaf litter of studied mangroves in
Ghana were observed in June, and in Cameroon from June
to September and October for Avicennia and Rhizophora,
Search WWH ::
Custom Search