Wetlands Ecol Manage (2010) 18:233–242
DOI 10.1007/s11273-009-9162-6
ORIGINAL PAPER
Mangrove rehabilitation dynamics and soil organic
carbon changes as a result of full hydraulic restoration
and re-grading of a previously intensively managed shrimp
pond
N. Matsui • J. Suekuni • M. Nogami
S. Havanond • P. Salikul
•
Received: 28 January 2009 / Accepted: 24 September 2009 / Published online: 27 February 2010
Ó Springer Science+Business Media B.V. 2010
Abstract Hydraulic restoration by opening the
shrimp pond banks facilitated the establishment of
planted mangroves and colonisation by non-planted
mangrove species and was shown to be an effective
method of mangrove rehabilitation. Planted Rhizophora apiculata and Rhizophora mucronata had
grown significantly in 6 years, to 300 and 350 cm,
respectively. However, the growth rate of Bruguiera
cylindrica was merely 150 cm in the same period
despite vigorous growth in the initial stage. About 15
non-planted mangrove species had colonised within
6 years after reopening the banks, with the dominant
species being Avicennia marina (46.9%) followed by
B. cylindrica (27.0%) and Ceriops tagal (14.9%).
After the enhancement, soil organic carbon increased
considerably from 110 to 160 tonC ha-1 in 2 years at
the lower elevation, indicating that hydraulic restoration could stimulate carbon recovery through
enhancement of mangrove growth. However, soil
organic carbon decreased by almost half in the higher
N. Matsui (&) J. Suekuni
Department of Environment, Kanso Technos Co., Ltd.,
Osaka 541-0052, Japan
e-mail: [email protected]
M. Nogami
Power Engineering R&D Center, The Kansai Electric
Power Co., Inc., Kyoto 609-0237, Japan
S. Havanond P. Salikul
Department of Marine and Coastal Resources, Payatai,
Bangkok 10400, Thailand
ground, suggesting that carbon decomposition was
accelerated due to drying of soils.
Keywords Rehabilitation Mangroves Hydraulic restoration Colonisation Soil organic carbon
Introduction
Mangrove ecosystems have been considered to
provide valuable benefits such as shoreline protection
(Katherine et al. 1998), the maintenance of biodiversity (Macintosh et al. 2002), a sustainable basis for
the livelihood of local people (Sathirathai 1998), and
the creation of fishery resources (Sheridan 1997;
Barbier and Strand 1998). Therefore the loss of
mangrove forests is likely to affect considerably both
the economy and the ecosystem of a coastal area.
In Thailand, the specific causes of mangrove
destruction up to 1986 were: conversion to shrimp
ponds (64% (by area)), coastal development (26%),
other activities including salt ponds (6%), and tin
mining (3%) (Aksornkoae et al. 1993). As such,
shrimp farming has been the main cause of mangrove
destruction in Thailand. As a result of the development of intensive farming technology for tiger shrimp
(Penaeus monodon) in 1985, shrimp production
increased remarkably and consequently larger areas
123
234
Wetlands Ecol Manage (2010) 18:233–242
were devoted to shrimp culture. In 1972, the total
area used for shrimp farming was only 90.6 km2, but
this increased to approximately 700 km2 in 1994. The
majority of shrimp farms in Thailand are abandoned
after 5 years because of drastic declines in yields
resulting from shrimp viral diseases (Sathirathai and
Barbier 2001). As a consequence, an unquanitfied but
significant area of shrimp ponds has been abandoned.
Abondoned ponds are effectively useless to the local
people.
As a result, a number of mangrove rehabilitation
projects have been undertaken by both the government and the private sector, resulting in the establishment of approximately 29 km2 of plantations
by 1999. However, mangrove replanting has commonly been carried out simply by planting mangrove seedlings without adequate site assessment or
subsequent evaluation of planting at the ecosystem
level (Field 1996).
The failure of many attempts to restore former
ponds has been attributed to ignoring the hydrology
(Elster 2000). Lewis (2000, 2005) emphasized that
rehabilitation of mangroves could be achieved
through restoring the natural hydrology (Turner and
Lewis 1997) or hydrologic reconnection to the
surrounding water system (Brockmeyer et al. 1997).
However, hydraulic restoration has scarcely been
conducted in abandoned, formerly intensive farmed
ponds. Intensive shrimp farming normally involves
the construction of elevated pond walls (1.2–1.8 m in
height from the pond bottom) to retain the large
volumes of water required to cultivate great numbers
of shrimp. Once the ponds are abandoned these banks
remain as an obstruction to water flow (Fig. 1a).
Fig. 1 a Initial condition of experimental plot before reopening the banks (April 1999). Note that there was no vegetation in
the pond at this stage, b banks surrounding the pond, were
breached by heavy machinery and soils from these banks were
used for re-grading the pond (June 1999), c immediately after
mangrove planting (September 1999), d aerial photograph of
the study site taken 6 years after planting (October 2005). This
view was taken by a remote controlled helicopter from 500 m
above the sea level. The large rectangular area shows the
location of the experimental plantation plot (approximately
6,525 m2). The small rectangular area (5 m 9 60 m) is where
the colonising species were counted. The circle indicates the
location of creek mouth
123
Wetlands Ecol Manage (2010) 18:233–242
Physical land modification is thus required for
successful mangrove replanting in abandoned intensive shrimp ponds. In this study, we reopened and regraded obstructing banks surrounding a shrimp pond
as a method of hydraulic restoration and examined
the effectiveness of this approach for rehabilitating
mangrove forest.
Natural regeneration via non-planted mangrove
propagules was observed within rehabilitated mangrove stands (Stevenson et al. 1999; Bosire et al.
2003). Although natural regeneration may be able to
substitute for conventional planting, tree growth
performance after colonisation has still not been fully
understood. This aspect of colonisation was thereby
examined in this study.
Soil organic carbon (SOC) has received a great
deal of attention in the context of global warming
since a vast amount of organic carbon is stored in
mangrove soils (Matsui 1998; Matsui and Yamatani
2000). Land use changes in mangrove ecosystems,
such as a conversion to shrimp ponds and subsequent
abandonment, seem to influence both the quantity and
the quality of SOC. This study therefore aimed to
measure quantitative changes of SOC before and after
physical modification.
Methods
Study site
The study was conducted in an abandoned, formerly
intensively managed shrimp pond, located in Thong
Nian sub-district, Khanom district, Nakorn Sri
Thammarat province, Thailand (9°170 N, 99°490 E).
Nakorn Sri Thammarat province has a relatively low
mean annual precipitation of 1,710 mm (1997 and
2003), with a mean annual temperature of 27.4°C.
Khanom was formerly covered with extensive mangrove forests, however, the majority of this area was
cleared in the 1980s to develop commercial shrimp
farms. Since then, local villagers have attempted to
replant mangroves after recognizing that the mangroves had been cleared to such a critical level that
aspects of their livelihood, such as fishing, were
suffering. Despite these attempts, several replanting
trials failed in the study site because of the changed
local hydraulic condition.
235
Physical land modification
The abandoned shrimp pond was prepared by
reopening the obstructing banks on all sides in June
1999 using heavy machinery (Fig. 1b). The breached
banks were leveled and the spoil utilized to re-grade
the pond area. Consequently, the frequency of tidal
flooding was greatly increased compared to previously, when water could just flow in and out from the
10 m long mouth. Spot heights were measured with
an auto-level (AC-2S; Nikon Co., Ltd., Tokyo, Japan)
in December 2007. Mean sea water level (MSL) and
mean high tide water level (MHL) were calculated by
referring to the tidal records obtained in Ko Prap
(Suratthani province) which is the nearest observatory to the study site (Fig. 2b). Furthermore, the tidal
characteristics of Ko Prap were examined in terms of
sea level change in 2007 (Fig. 3), revealing that the
tidal level in the study site tended to be lower
between March and September.
Mangrove planting
After breaching the pond walls, the land was left for
3 months to adjust to the changed conditions prior to
mangrove planting. This delay is frequently undertaken to allow plants to grow more successfully in
modified condition. The seedlings of four different
mangrove species, Rhizophora mucronata Lamk
(Rm), Rhizophora apiculata Bl. (Ra), Bruguiera
cylindrica (L.)Bl. (Bc), and Ceriops tagal (Perr.)
C.B.Robinson (Ct) were planted at a spacing of
1.5 9 1.5 m across an area of 6,525 m2 in September
1999 (Fig. 1c). Bc and Ct were planted on the former
bank area because they grow at higher elevations than
Rm and Ra in a natural habitat. On the other hand,
Rm and Ra were planted within the former pond area
because of their preference for a longer duration of
tidal inundation. The area comprising of the Ct zone
and the Bc zone is referred to as ‘BANK’, and the
area belonging to the Ra and Rm zone as ‘POND’
(Fig. 2a). In total, 800 seedlings of Rm, Ra and Ct,
and 500 seedlings of Bc were planted in the study.
Tree heights/survival rate measurements
and identification of colonising mangrove species
Following the planting in September 1999, tree
heights and survival rates were measured four times
123
236
Wetlands Ecol Manage (2010) 18:233–242
A
B
60 m
POND
BANK
Zones
Ct
Relative ground level (cm)
BANK
Bc zone
Rm zone
Ra zone
Ctzone
120 m
Ra
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
Bc
A
Surface level after
land modification
B
MHL
C
Bottom level of
shrimp pond
0
5m
Rm
Surface level of the
bank before land
modification
10
20
15 m
30
40
50
60
Horizontal distance (m)
The mouth to the creek
Fig. 2 a Layout of the experimental plantation. The rectangular area (5 9 60 m) indicates where colonising mangrove
species were counted. The horizontal double line shows where
ground levels were measured, b cross section of the study site,
indicating ground levels before and after physical land
modification. The heights of banks from the bottom of the
shrimp pond changed from 1.3 m down to 0.5–0.7 m during
physical modification. The MHL denotes the mean high tide
water level. Letter A indicates the surface level of the bank
before modification, and B, C signify the surface levels of the
Ct zone and of the Ra and Rm zones after modification,
respectively
350
A
300
Sea level (cm)
B
250
C
200
150
100
December
November
October
September
August
July
June
May
April
March
February
0
January
50
Month
Fig. 3 Sea level change measured in 2007 at Ko Prap
(Suratthani province) which is the nearest observatory to the
study site. A surface level of the bank before modification,
B surface level of Ct zone after modification, C surface level of
Ra, Rm zones after modification
in December 1999, October 2000, November 2003,
and October 2005, representing intervals of approximately 3 months, 1, 4, and 6 years after planting,
respectively. To monitor results we marked 10%
of the trees from each group at random, at the
beginning (December 1997) to form a control group.
This constituted 80 trees each for Rm, Ra and Ct,
and 50 trees for Bc. This enabled us to measure
repeatedly tree heights and survival rates of the same
trees.
123
Wetlands Ecol Manage (2010) 18:233–242
237
120
Tree height
3 months
1 year
Survival rate
3 months
1 year
Tree height (cm)
a
Survival rate and tree growth
During the initial stages of growth, at 3 months and
1 year after planting, high survival rates were
observed in Ra, Rm and Bc but low in Ct (Fig. 4).
Moreover, the tree heights of Ra, Rm and Bc
increased significantly over the same period, but
those of Ct increased insignificantly (Fig. 4). Of the
four planted species, the growth rate between
3 months and 1 year was highest for Bc, followed
by Rm and then Ra.
The increase rates of tree height over the whole
6 years from planting are ranked as follows:
Bc \ Ct \ Ra \ Rm (Fig. 5). Rm recorded the
greatest increase of 357 cm. Ct showed greater
80
d
c
80
70
60
b
60
50
a
40
b
b
40
a
30
a
20
10
0
Ct
Ra
Rm
0
Bc
Fig. 4 Changes in the mean tree height and the survival rate
during the initial stage, from 3 months to 1 year after
planting. Ct—Ceriops tagal, Ra—Rhizophora apiculata, Rm—
Rhizophora mucronata, Bc—Bruguiera cylindrica. Bars
denote the means and standard deviations of 30–100 replicates
600
RM
BC
CT
RA
500
c
400
b
300
b
b
200
a
a
a
b b b
c
100
a
0
Results
b
90
20
Tree height (cm)
Soil samples were randomly collected from the
surface (0–5 cm) three times at July 2003, October
2005 and December 2007 which constitute intervals
of 4, 6, and 8 years, respectively after physical land
modification. Approximately 10 points from both
POND and BANK were randomly chosen for sample
collection. Bulk samples were taken at July 2003,
while samples from October 2005 to December 2007
were collected with 100 cc volumetric cylinders
(DIK-5561; Daiki Rika Kogyo Co., Ltd., Kounosu,
Japan) to determine bulk density. Soil organic carbon
(SOC) was determined using the dry combustion
method (NC-analyzer 1000; Sumigraph, Shimadzu
Co., Ltd., Kyoto, Japan) and CN ratio calculated.
After the determination of bulk density by drying
100 cc cylinder samples at 120°C for 3 days, carbon
levels were calculated from SOC and bulk density.
Statistical analyses were carried out for the measured
tree and soil data using Tukey’s HSD test (JMP 4.0,
SAS Institute Inc.) and differences at the P \ 0.05
level were considered to be significant.
b
c
b
100
b
Soil sampling and analysis
100
b
b
Survival rate (%)
Non-planted mangrove species also colonised the
study site, which were therefore identified and tree
heights of each colonising species were measured in
October 2005, 6 years after planting, for 4.5% of total
planted area in 5 9 60 m area (Fig. 2a).
b
b
1999 Dec
a
2000 Oct
2003 Nov
2005 Oct
Fig. 5 Changes in the mean tree height over the 6 years from
planting. Bars denote the means and standard deviations of 30–
100 replicates. Data with different letters are significantly
different (Tukey’s HSD test, P \ 0.05). Ct—Ceriops tagal,
Ra—Rhizophora apiculata, Rm—Rhizophora mucronata,
Bc—Bruguiera cylindrica
growth (168 cm) than Bc (149 cm) even though Bc
demonstrated superior growth at the initial stage.
Colonisation of non-planted mangroves
Six years after physical land modification (October
2005), the following 15 non-planted mangrove species were identified in an 5 9 60 m area: Avicennia
marina (Am), Bc, Ceriops decandra (Cd), Xylocarpus moluccensis, Ct, Ra, Rm, Lumnitzera racemosa,
123
238
Wetlands Ecol Manage (2010) 18:233–242
Avicennia alba, Xylocarpus granatum, Sonneratia
alba, Excoecaria agallocha, Hibiscus tiliaceus, Thespesia populnea, and Bruguiera sexangula. All the
colonising species except S. alba and B. sexangula
are tolerant of dry conditions. The colonising species
with the greatest number of trees were Am (842
trees), Bc (486 trees) and Cd (267 trees), (Table 1).
The Bc and Ct zones, at higher elevation, recorded
the greatest number of colonising plants, at 673 trees
and 579 trees, respectively. On the other hand, there
were far fewer colonising trees at the lower elevation
(206 trees in the Rm zone, 170 trees in the Ra zone).
Standard deviation of tree heights was high in the
colonising trees, which suggests that the establishment of the colonising trees was largely influenced by
variation of tree density and resulting shade on the
colonising trees.
Table 1 Number of colonising mangrove species found in a
5 9 60 m area
Zone
Total
BANK
POND
CT
BC
RA
RM
Am
290
491
49
12
842
Bc
Cd
164
72
182
110
75
7
65
78
486
267
Xm
28
16
11
14
69
Ct
25
5
6
36
Ra
1
11
22
34
Rm
3
Lr
15
Xg
2
1
6
3
2
Ea
1
1
Ht
1
1
Tp
1
1
Bs
1
673
170
206
20
October 2005
a
a
December 2007
b
15
a
a
a
c
a
a
b
b
10
5
1,797
Notation Am: Avicennia marina, Bc: Bruguiera cylindrica, Cd:
Ceriops decandra, Xm: Xylocarpus moluccensis, Ct: Ceriops
tagal, Ra: Rhizophora apiculata, Rm: Rhizophora mucronata,
Lr: Lumnitzera racemosa, Aa: Avicennia alba, Xg: Xylocarpus
granatum, Sa: Sonneratia alba, Ea: Excoecaria agallocha, Ht:
Heritiera tiliaceus, Tp: Thespesia populnea, Bs: Bruguiera
sexangula
123
July 2003
a
9
3
2
579
25
30
15
Sa
Total
Figure 5 shows SOC of the studied soils at 4 years
(July 2003), 6 years (October 2005) and 8 years
(December 2007) after planting. The mean SOC
measured in July 2003 were 2.1 9 10-2 kg kg-1 in
the Ra, Rm zones, 2.4 9 10-2 kg kg-1 in the Bc
zone and 3.2 9 10-2 kg kg-1 in the Ct zone.
Between 4 and 6 years after planting (July 2003–
October 2005), SOC changed slightly in BANK, but
increased markedly in POND. Over this period, SOC
increased by 0.76 9 10-2 kg kg-1 in the Ra zone,
0.51 9 10-2 kg kg-1 in Rm zones, but only
0.09 9 10-2 kg kg-1 in the Bc zone, and decreased
by 0.04 9 10-2 kg kg-1 in the Ct zone (Fig. 5). A
significant increase of SOC in the Ra, Rm zones
could have been caused by improved hydraulic
conditions and subsequent enhanced tree growth.
From 6 to 8 years after planting (October 2005–
December 2007), SOC increased in the Rm zone by
0.43 9 10-2 kg kg-1 and in the Ra zone by
0.17 9 10-2 kg kg-1. However, it decreased in the
Bc zone by 1.52 9 10-2 kg kg-1 and in the Ct zone
by 1.00 9 10-2 kg kg-1, indicating that soil carbon
decomposed considerably at the higher elevation. CN
ratios decreased steadily in BANK (Ct, Bc zones),
however, they increased in POND (Ra, Rm zones)
from July 2003 to December 2007 (Fig. 6).
As regards to the carbon stock, 269 tonC ha-1 was
stored in BANK at October 2005, however, it
CN ratio
Aa
27
Carbon accumulation
0
Ct
Ra
Rm
Bc
Fig. 6 Soil organic carbon measured in July 2003, October
2005 and December 2007. Bars denote the means and standard
deviations of four replicates (July 2003) and 6 replicates (Oct.
2005 and Dec. 2007). Data with different letters are
significantly different (Tukey’s HSD test, P \ 0.05)
Wetlands Ecol Manage (2010) 18:233–242
July 2003
a
a
b
b
c
December 2007
b
a a
a
a
2.5
2.0
1.5
b
1.0
0.5
Ct
Ra
Rm
Bc
Zone
Fig. 7 CN ratios measured in July 2003, October 2005 and
December 2007. Bars denote the means and standard
deviations of four replicates (July 2003) and 6 replicates
(Oct. 2005 and Dec. 2007). Data with different letters are
significantly different (Tukey’s HSD test, P \ 0.05)
decreased by almost half to 144 tonC ha-1 in just
2 years at December 2007 (Fig. 7). But in contrast,
the carbon stock increased in POND from 110 to
160 tonC ha-1 in the same period (Fig. 8).
Discussion
Mangrove plantation
Survival and growth rates of planted trees reflect
various environmental factors including hydrology.
Little quantitative data on mangrove seeding survival
have been published (Hutchings and Saenger 1987;
Clarke and Allaway 1993). Hutchings and Saenger
(1987) found that survival rates of Rhizophora and
a
50
0
Bank
Pond
Fig. 8 Carbon stock measured in October 2005 and December
2007. Bars denote the means and standard deviations of eleven
replicates (Oct. 2005 and Dec. 2007). Data with different
letters are significantly different (Tukey’s HSD test, P \ 0.05)
40
20
0
December
100
60
October
150
80
November
a
(C) Surface level of Ra, Rm zones
after modification
100
September
200
120
August
b
b
July
250
(B) Surface of Ct zone after
modification
140
June
December 2007
160
May
October 2005
300
April
tonC ha-1 in 5cm depths
350
March
0.0
February
3.0
b
Ceriops were variable and site-dependent with 64 and
28% survival rates in the first year. The survival rate of
Rhizophora was low because their study site faced the
open sea where wave energy was significant. Our study
site received no wave energy. Rm and Ra grew better
than Ct, which is attributed to hydraulic restoration
leading to a higher frequency of tidal inundation in
POND. Ct was planted in BANK where the ground
level was 30 cm higher than the Ra, Rm zones and
higher than MSL as well (Fig. 2b). It was observed that
planted mangroves continued to grow in the Ct zone
despite the lack of inundation for 7 months of the year
(Fig. 9). Mangroves have been reported to grow above
MSL (Ellison 2009). However, our study demonstrated that Ct can grow even higher than MHL,
although its survival rate is rather low.
Growth rates of Bc were high during the initial
stage but they decreased at a later stage. However,
growth rates of Ct were poor during the initial stage,
but surpassed those of Bc later on. This fact suggests
that growth performance changes during the growing
period, and that initial growth is not always indicative
of growth rates later on.
The standard deviation of tree height increased
between December 1999 and October 2005 for all
species (Fig. 5). In accordance with forest development in a planted mangrove stand, spatial variance
of site qualities controlling tree growth increased
(Matsui and Kosaki 2007a). As a consequence, differences in tree heights among planted trees increased.
The highest standard deviation of tree height was
found in Ra, suggesting that Ra is likely to be most
affected by changes in site qualities.
January
x 10-2 kg kg-1
3.5
October 2005
Inundation duration (hours)
4.5
4.0
239
Month
Fig. 9 Inundation duration (h) per month in 2007 calculated
for two different surface levels (B, C) shown in the Fig. 2b
123
240
Wetlands Ecol Manage (2010) 18:233–242
Colonisation
Most of colonising mangrove species in the study site
were tolerant to dry conditions, with Am being the
dominant species. Mangrove ecosystems are influenced by seasonal changes of sea level (Snedaker
1989; Kjerfve 1990; Mazda et al. 2003). The
difference of the mean sea level between summertime
and wintertime was approximately 35 cm (Fig. 3) in
the study region, indicating that the study site
becomes considerably drier in summertime. Reopening of the obstructing pond banks has produced
favourable conditions which have facilitated many
dry-tolerant species to colonise the site. The study
site had been devoid of vegetation for a long time
after the conversion from mangrove in 1980s. However, species richness had significantly increased by
reopening the banks, as is shown by comparing two
images, Fig. 1a, d. The substrate of POND is unstable
due to frequent tidal flooding, which may be one of
the reasons why fewer species could colonise this
zone. The colonising species are common in the area
surrounding the study site, and the seeds and
propagules of these species could access the site
only after the reopening of the banks. The degree of
recruitment was strongest near the creek mouth
(Fig. 1d) and reduced with increasing distance from
this opening. This can be related to transferability of
seeds and propagules. Waterborne propagules of Ra/
Rm were less able to enter the pond even after
reopening the banks due to the physical constraints of
transportation influenced by the larger size of Ra/Rm
propagules.
In Suratthani province which is adjacent to this
study site, 12 mangrove species colonised an abandoned shrimp pond, with a predominance of Avicennia officinalis (42%) and Sonneratia alba (36%)
(personal communication, Mr. Ketkaew). Stevenson
et al. (1999) also observed that A. marina was the
initial colonising species during the first 5 years after
reopening pond banks in the Philippines. These
findings, together with our results, indicate that
Avicennia spp. are capable of pioneering propagation
in abandoned shrimp ponds. Certain physiological
characteristics are believed to give Avicennia spp. the
ability to colonise a site more quickly than other
mangrove species, including low stomatal resistance,
low tissue water potential, high relative water content
and high tissue cation concentration (Naido 2003).
Colonising tree heights and those of planted trees
were almost identical in Ra, Rm (Table 2), which
suggests that hydraulic restoration is quite effective
for mangrove rehabilitation. However, tree heights of
Ct, Bc were much higher for planted compared to
colonising trees, indicating that conventional planting
is still effective and necessary for planting these
species.
Carbon changes
Carbon stocks were rather low (144–160 tonC ha-1)
compared to those of natural mangrove (370–
553 tonC ha-1), but approximately similar to deltaic
sediment (104–162 tonC ha-1) (Matsui and Kosaki
2007b). It is likely that large amounts of carbon have
been lost in the course of pond construction and/or
after abandonment of shrimp pond. Mangrove ecosystems form large and dynamic reservoirs of carbon,
which is an important part of the global carbon cycle
and a potential sink for atmospheric CO2. However,
mangrove SOC is susceptible to decomposition due
to the abundance of aliphatic-rich humic acids which
easily change to carboxylic humic substances by
humification (Matsui and Kosaki 2007b; Orlov 1995;
Yonebayashi 1994, 2009). This inherent characteristic of mangrove SOC may lead into accelerated
Table 2 Mean tree height (cm) of planted and colonized CT, BC, RA, RM measured at October 2005
Zone
Colonized trees
Mean tree height (cm)
BANK
POND
Number of trees
Mean tree height (cm)
Number of trees
36
CT
61.9 ± 072.4
40
192.8 ± 49.9
BC
93.8 ± 175.7
186
189.0 ± 69.9
43
RA
310.3 ± 182.3
26
330.8 ± 106
45
RM
487.7 ± 124.7
27
428.5 ± 59.3
70
Data are mean ± standard deviation
123
Planted trees
Wetlands Ecol Manage (2010) 18:233–242
carbon decomposition in an abandoned shrimp pond,
especially when soils are exposed to the air. This is
supported in our study by the fact that the CN ratio
had decreased in BANK where the soil surface was
exposed to the air for a long period of time. Therefore
inappropriate land use in mangrove areas risks
inducing a significant carbon loss, transforming
mangrove areas into a source of CO2 emission. In
places where mangrove grows well, such as the Ra,
Rm zone, SOC recovery was relatively high. Since
the soil in the Ra, Rm zone was kept wet by frequent
tidal flooding, with inundation duration of 716 h per
year (Fig. 9), SOC was protected from severe
decomposition. In contrast, the Ct, Bc zone experienced drier soils due to less frequent tidal flooding,
with inundation duration of merely 183 h per year,
lowering the SOC recovery rate within the zone.
These data imply that hydraulic conditions play a
crucial role not only for mangrove rehabilitation but
also influence the levels of SOC.
Conclusions
Restricted water circulation in the pond, was
improved by reopening obstructing banks. As a
consequence, different growth performance was
observed for four planted mangrove species. Poor
growth and low survival rates of Ct and Bc could be
attributed to less frequent tidal flooding due to being
planted in ground 30 cm higher than Ra and Rm.
About 15 non-planted mangrove species had
colonised the pond within 6 years of reopening the
banks, with the dominant species being A. marina
(46.9%) followed by Bc (27.0%) and Ct (14.9%). The
majority of the colonising species were dry-tolerant,
which are widely distributed in the area surrounding
the study site. Tree heights of the colonising species
and of those planted were almost identical in Ra and
Rm area, indicating that mangrove rehabilitation can
be achieved simply by hydraulic restoration. However, establishment of the colonising trees is significantly influenced by local conditions where the seed
or propagule takes root and the timing of their arrival,
as indicated by the high standard deviation of
colonising tree heights.
Carbon stocks in the surface soil (144–160
tonC ha-1) were a half to a quarter of those found
in natural mangrove, indicating that large amounts of
241
carbon were lost during conversion to shrimp activity
and/or after abandonment. Soil organic carbon markedly increased in the lower ground, which can be
related to enhanced mangrove growth caused by an
increased frequency of tidal flooding after the
reopening of the banks.
Acknowledgments The research works described in this
paper was undertaken as a part of Joint Research Project that
had been conducted among Department of Marine and Coastal
Resources (DMCR), Thailand, Kansai Electric Power Co., Inc.
and Kanso Technos Co., Ltd. from 1998 to 2007. We would
like to thank all staffs of Mangrove Resources Research &
Development Station Nr. 6, DMCR for their hard work in the
field.
References
Aksornkoae S, Paphavasit N, Wattayakorn G (1993)
Mangroves of Thailand: Present status of conservation,
use and management. In: Clough BF (ed) The Economic
and Environmental Values of Mangrove Forests and Their
Present State of Conservation in the South-East Asia
Pacific Region. International Society for Mangrove
Ecosystems, Okinawa, pp 83–133
Barbier EB, Strand I (1998) Valuing mangrove-fishery linkages—a case study of Campeche, Mexico. Environ
Resour Econ 12:151–166
Bosire JO, Dahdouh-Guebas F, Kairo JG, Koedam N (2003)
Colonisation of non-planted mangrove species into
restored mangrove stands in Gazi Bay, Kenya. Aquat Bot
76:267–279
Brockmeyer RE, Rey JR, Virnstein RW, Gilmore RG, Earnest
L (1997) Rehabilitation of impounded estuarine wetlands
by hydrologic reconnection to the Indian River Lagoon,
Florida (USA). Wetl Ecol Manag 4:93–109
Clarke PJ, Allaway WG (1993) The regeneration niche of the
grey mangrove (Avicennia marina): effects of salinity,
light and sediment factors on establishment, growth and
survival in the field. Oecologia 93:548–556
Ellison JC (2009) Geomorphology and sedimentology of
mangroves. In: Perillo GME, Wolanski E, Cahoon DR,
Brinson MM (eds) Coastal wetlands: an integrated ecosystem approach. Elsevier, Amsterdam, pp 565–591
Elster C (2000) Reasons for reforestation success and failure
with three mangrove species in Colombia. For Ecol
Manag 131:201–214
Field CD (1996) Restoration of mangrove ecosystems. International Society for Mangrove Ecosystems, Okinawa
Hutchings P, Saenger P (1987) Ecology of mangroves. University of Queensland Press, St Lucia
Katherine C, Ewel KC, Twilley RR, Ong JE (1998) Different
kinds of mangrove forests provide different goods and
services. Global Ecol Biogeogr Lett 7:83–94
Kjerfve B (1990) Manual for investigation of hydrological
processes in mangrove ecosystems. The UNESCO/UNDP
regional project ‘Mangrove ecosystems in Asia and the
123
242
Pacific, RAS/79/002 and RAS/86//120’, Thomson Press,
p 79
Lewis RR (2000) Ecologically based goal setting in mangrove
forest and tidal marsh restoration. Ecol Eng 15:191–198
Lewis RR (2005) Ecologically engineering for successful
management and restoration of mangrove forests. Ecol
Eng 24:403–418
Macintosh DJ, Ashton EC, Havanond S (2002) Mangrove
rehabilitation and intertidal biodiversity: a study in the
Ranong mangrove ecosystem, Thailand. Estuar Coast
Shelf Sci 55:331–345
Matsui N (1998) Estimated stocks of organic carbon in mangrove roots and sediments in Hinchinbrook Channel,
Australia. Mangrove Salt Marshes 2:199–204
Matsui N, Kosaki T (2007a) Spatial and temporal evaluation of
mangrove (Rhizophora mucronata Lamk.) tree heights and
soil properties in 3-years and 7-years after the mangrove
plantation. In: Tateda Y, Upstill-Goddard R, Goreau T,
Alongi D, Nose A, Kristensen E, Wattayakorn G (eds)
Greenhouse gas and carbon balances in mangrove coastal
ecosystems. Gendaitosho, Japan, pp 93–107
Matsui N, Kosaki T (2007b) Quantitative and qualitative
evaluation on stored carbons of mangrove ecosystems in
Chumphon, Thailand. Mangrove Sci 5:13–19
Matsui N, Yamatani Y (2000) Estimated total stocks of sediment carbon in relation to stratigraphy underlying the
mangrove forests of Sawi Bay. Phuket Mar Biol Cent
Spec Publ 22:15–25
Mazda Y, Wolanski E, Ridd PV (2003) The role of physical
processes in mangrove environments. Terrapub publisher,
Tokyo
Naido G (2003) Effects of waterlogging and salinity on plantwater relations and on the accumulation of solutes in three
mangrove species. Aquat Bot 22:133–143
123
Wetlands Ecol Manage (2010) 18:233–242
Orlov DS (1995) Humic substances of soils and general theory
of humification. A.A.Balkema/Rotterdam/Brookfield,
Moscow
Sathirathai S (1998) Economic valuation of mangroves and the
roles of local communities in the conservation of natural
resources: case study of Surat Thani. South of Thailand.
EEPSEA Research Report Series, Economy and Environment Program for Southeast Asia, Singapore
Sathirathai S, Barbier EB (2001) Valuing mangrove conservation in Southern Thailand. Contemp Econ Policy 19:
109–122
Sheridan P (1997) Benthos of adjacent mangrove, seagrass and
non-vegetated habitats in Rookery Bay, Florida, USA.
Estuar Coast Shelf Sci 44:455–469
Snedaker SC (1989) Overview of ecology of mangroves and
information needs for Florida Bay. Bull Mar Sci 44:
341–347
Stevenson NJ, Lewis RR, Burbridge PR (1999) Disused shrimp
ponds and mangrove rehabilitation. In: Streever WJ (ed)
An international perspective on wetland rehabilitation.
Kluwer, Netherlands, pp 277–297
Turner RE, Lewis RR (1997) Hydrologic restoration of coastal
wetlands. Wetl Ecol Manag 4:65–72
Yonebayashi K (1994) Humic component distribution of humic
acids as shown by adsorption chromatography using
XAD-8 resin. In: Senesi N, Miano TM (eds) Humic
substances in the global environment and implications on
human health. Elsevier Sciences, Amsterdam, pp 181–186
Yonebayashi K (2009) Humic substances in soils. In: Ishiwatari R, Yonebayashi K, Miyajima T (eds) Humic substances in environments. Characteristics and research
methods. Sankyo Shuppan, Tokyo, pp 10–29