Abstract
Deforestation and degradation of mangrove forests have become one of
the main issues for coastal ecosystems in Indonesia and elsewhere in
Southeast Asia. Over the past decades, over-exploitation of timber, firewood,
charcoal production, housing materials, and commercial logging and conversion
into other forms of land use such as agriculture, settlement, mining, and
especially aquaculture have led to a reduction in the extent of mangrove forests
and their biodiversity, which has had significant effects on local communities.
This thesis addresses mangrove forest change over the past 33 years
and the environmental and socioeconomic consequences of the observed
changes for communities living around mangrove areas. In this connection, the
effects of mangrove exploitation on biodiversity and ecosystem services,
including forestry and fishery products, are explored. Finally, the total economic
value of mangroves is calculated, including the direct use value, the indirect use
value, and the option value, and compared to the benefit value of commercial
aquaculture.
Takalar district of South Sulawesi province has been chosen as a case
study for exploring changes as it is one of the mangrove hotspots of Indonesia
and it is under intense pressure from exploitation.
The results show that mangrove forest areas were continually reduced
during the full period of analysis from 1979-2011 by a total of 3,344 hectares.
The biggest annual negative change of density in mangrove forest cover
(8.37%) occurred during the period 2006–2011. The changes were caused
mainly by the conversion to aquaculture, and the consequences have
manifested themselves as increasing forest degradation, coastal abrasion,
seawater intrusion, a decline in volumes of captured fish, a reduction in shrimp
and milkfish fry, and outbreaks of shrimp disease. However, the expansion of
aquaculture ponds and seaweed development have provided new opportunities
for alternative employment in the study area, and the production and export
value of shrimp and seaweed provide foreign exchange.
Ten species of mangrove were recorded (Avicennia alba, Bruguiera
gymnorrhiza, Ceriops tagal, Excoecaria agallocha, Lumnitzera racemosa, Nypa
fruticans, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa,
and Sonneratia alba) belonging to six families (Avicenniaceae, Rhizophoraceae,
Euphorbiaceae, Combretaceae, Arecaceae, and Sonneratiaceae). However,
the number, diversity, and density of species have decreased. Mangroves are
now dominated by saplings and seedlings, with few trees being above 15 cm in
diameter at breast height. Rhizophora sp. was found to be the most important
and dominant mangrove species and is also the most widely used by
communities as it is very suitable for firewood and charcoal production. In
addition, it is the main species planted in mangrove restoration projects, which
have focused on establishing production forests rather than restoring natural
species composition and structure. Despite the decrease in biodiversity, the
mangroves still provide a wide range of ecosystem services, such as fishery
products (fish, crabs, and shrimps) and forestry products (firewood, charcoal,
and Nypa palm leaves for crafting), to the communities in the area.
The TEV (Total Economic Value) of mangroves was in the range of 4,370
thousand USD (kUSD) to 10,597 kUSD or 4 kUSD to 8 kUSD per hectare (The
largest value contribution was derived from the indirect use value (94%)),
whereas commercial aquaculture has a net benefit value of 228 kUSD or 3
kUSD per hectare. The conversion of mangroves into commercial aquaculture
was found to have a higher beneficial value than the DUV (Direct Use Value;
the benefit value of fishery and forestry products) and OV (Option Value; benefit
value of medicines) of mangroves and the financial returns from converting
mangroves into commercial aquaculture seem reasonable. However, when the
IUV of mangroves is included in the comparison, the value of mangroves is
considerably higher. When the analysis was expanded to cover the costs of
environmental and forest rehabilitation, the conversion was not economically
beneficial.
On the basis of the above findings, several policy recommendations can
be considered for sustainable mangrove forest management, including (1)
Reforestation and rehabilitation of mangrove forest; (2) Establishment of a
natural conservation zone and green belt (buffer zone) to ensure that essential
parts of the mangroves remain undisturbed; (3) The promotion of alternative
employment creation to ensure sustainable livelihoods for local communities;
(4) Awareness raising regarding the necessity of performing a proper
assessment of the economic benefits value of mangrove that will be lost if the
mangroves are converted into commercial aquaculture. The results of this
assessment must be considered in any decision-making concerning mangrove
use, including the development of aquaculture businesses; (5) Providing direct
payments as compensation to communities in order to maintain and enhance
existing (intact) mangroves, including their goods and services, and providing
incentives for mangrove reforestation and rehabilitation; and (6) Development
and implementation of integrated mangrove aquaculture systems that are
environmentally friendly and socio-economically beneficial by managing
aquaculture systems similar to, or inspired by, the concept of silvofishery, where
fishponds (for farming fish and shrimps) are combined with mangrove trees in
the ponds.
the main issues for coastal ecosystems in Indonesia and elsewhere in
Southeast Asia. Over the past decades, over-exploitation of timber, firewood,
charcoal production, housing materials, and commercial logging and conversion
into other forms of land use such as agriculture, settlement, mining, and
especially aquaculture have led to a reduction in the extent of mangrove forests
and their biodiversity, which has had significant effects on local communities.
This thesis addresses mangrove forest change over the past 33 years
and the environmental and socioeconomic consequences of the observed
changes for communities living around mangrove areas. In this connection, the
effects of mangrove exploitation on biodiversity and ecosystem services,
including forestry and fishery products, are explored. Finally, the total economic
value of mangroves is calculated, including the direct use value, the indirect use
value, and the option value, and compared to the benefit value of commercial
aquaculture.
Takalar district of South Sulawesi province has been chosen as a case
study for exploring changes as it is one of the mangrove hotspots of Indonesia
and it is under intense pressure from exploitation.
The results show that mangrove forest areas were continually reduced
during the full period of analysis from 1979-2011 by a total of 3,344 hectares.
The biggest annual negative change of density in mangrove forest cover
(8.37%) occurred during the period 2006–2011. The changes were caused
mainly by the conversion to aquaculture, and the consequences have
manifested themselves as increasing forest degradation, coastal abrasion,
seawater intrusion, a decline in volumes of captured fish, a reduction in shrimp
and milkfish fry, and outbreaks of shrimp disease. However, the expansion of
aquaculture ponds and seaweed development have provided new opportunities
for alternative employment in the study area, and the production and export
value of shrimp and seaweed provide foreign exchange.
Ten species of mangrove were recorded (Avicennia alba, Bruguiera
gymnorrhiza, Ceriops tagal, Excoecaria agallocha, Lumnitzera racemosa, Nypa
fruticans, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa,
and Sonneratia alba) belonging to six families (Avicenniaceae, Rhizophoraceae,
Euphorbiaceae, Combretaceae, Arecaceae, and Sonneratiaceae). However,
the number, diversity, and density of species have decreased. Mangroves are
now dominated by saplings and seedlings, with few trees being above 15 cm in
diameter at breast height. Rhizophora sp. was found to be the most important
and dominant mangrove species and is also the most widely used by
communities as it is very suitable for firewood and charcoal production. In
addition, it is the main species planted in mangrove restoration projects, which
have focused on establishing production forests rather than restoring natural
species composition and structure. Despite the decrease in biodiversity, the
mangroves still provide a wide range of ecosystem services, such as fishery
products (fish, crabs, and shrimps) and forestry products (firewood, charcoal,
and Nypa palm leaves for crafting), to the communities in the area.
The TEV (Total Economic Value) of mangroves was in the range of 4,370
thousand USD (kUSD) to 10,597 kUSD or 4 kUSD to 8 kUSD per hectare (The
largest value contribution was derived from the indirect use value (94%)),
whereas commercial aquaculture has a net benefit value of 228 kUSD or 3
kUSD per hectare. The conversion of mangroves into commercial aquaculture
was found to have a higher beneficial value than the DUV (Direct Use Value;
the benefit value of fishery and forestry products) and OV (Option Value; benefit
value of medicines) of mangroves and the financial returns from converting
mangroves into commercial aquaculture seem reasonable. However, when the
IUV of mangroves is included in the comparison, the value of mangroves is
considerably higher. When the analysis was expanded to cover the costs of
environmental and forest rehabilitation, the conversion was not economically
beneficial.
On the basis of the above findings, several policy recommendations can
be considered for sustainable mangrove forest management, including (1)
Reforestation and rehabilitation of mangrove forest; (2) Establishment of a
natural conservation zone and green belt (buffer zone) to ensure that essential
parts of the mangroves remain undisturbed; (3) The promotion of alternative
employment creation to ensure sustainable livelihoods for local communities;
(4) Awareness raising regarding the necessity of performing a proper
assessment of the economic benefits value of mangrove that will be lost if the
mangroves are converted into commercial aquaculture. The results of this
assessment must be considered in any decision-making concerning mangrove
use, including the development of aquaculture businesses; (5) Providing direct
payments as compensation to communities in order to maintain and enhance
existing (intact) mangroves, including their goods and services, and providing
incentives for mangrove reforestation and rehabilitation; and (6) Development
and implementation of integrated mangrove aquaculture systems that are
environmentally friendly and socio-economically beneficial by managing
aquaculture systems similar to, or inspired by, the concept of silvofishery, where
fishponds (for farming fish and shrimps) are combined with mangrove trees in
the ponds.
| Originalsprog | Engelsk |
|---|
| Forlag | Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen |
|---|---|
| Antal sider | 169 |
| Status | Udgivet - 2015 |