instead, although these do not achieve full rewetting. The main reason is often
because box dam construction generates local employment and encourages communities to agree on the canal blocking. Also, the targeted peatland area should not have
been degraded to the extent that flooding is very common or almost continual. Peat
swamp forest species are tolerant of waterlogging and flooding, but this tolerance
also has its limits and if an area has been degraded (e.g., significant subsidence due to
fires and/or biological degradation) to a degree that flooding is prolonged and/or
deep these species may also succumb. Paludiculture should therefore target areas
that are degraded and have little or no tree cover (1–5%) but have only occasional
flooding (Giesen and Sari 2018).
Continued Focus on Dryland Species Most species currently cultivated on
peatland in Indonesia are dryland species such as oil palm, Acacia crassicarpa,
cocoa, Liberica coffee, Hevea rubber, dragonfruit, pineapple, Aloe vera, papaya, and
betel nut, but also a range of other fruit species such as durian (Durio zibethinus),
mango, and so on. These all require at least 40 cm or more drainage (some require at
least 50–60 cm), and some (dragon fruit, pineapple, Aloe) are even species adaptive
to (very) dry conditions (e.g., dragon fruit is a member of the cactus family). Their
cultivation on peatland is well known and provides a steady income, although
eventually this source of livelihood will in most cases disappear once peat subside
to the point that it can no longer be drained by gravity and flooding/waterlogging
becomes an issue. In most Indonesian peatland areas, the latter is not yet evident, and
hence there is very significant reluctance to rewet peatland and switch to unknown
paludiculture species. Also, there are currently few examples of true paludiculture
providing an alternative income and this forms a formidable barrier. Trials
attempting paludiculture often end up being compromised by agencies or NGOs
that would like to try sustainable alternatives, but at the same time do not want to
jeopardize farmer incomes. In these circumstances, rewetting is often only
conducted partially (e.g., GWL at 40 cm below surface) and replanting conducted
with a mix of peatland and dryland species.
Reluctance of Large Plantation Companies Large plantation companies have
made huge investments in plantations based on dryland species, and on infrastructure and processing capacities based on these dryland species. Investments to date by
these companies in alternative species have been minimal and hardly seem adequate
considering what is at stake, i.e. long-term survival of the present business models
operating on peatland.
Landscape Approach Needed Rewetting and paludiculture need to be well
embedded in the landscape, as due to hydrological characteristics of peatlands one
cannot manage a part of a peat dome in isolation. One cannot rewet part of a dome
and expect this to be effective if adjacent areas remain in a drained state, and hence
rewetting must be planned on a landscape level. It must also be carried out within a
brief time, for if it takes several seasons then previous work may end up becoming
undone (e.g., if fires take hold). An example of this is the 18,000 ha of Tahura of OKI
in Jambi, Sumatra, which forms the buffer zone of the threatened Berbak National
14 Tropical Peatland Restoration in Indonesia by Replanting with Useful Indigenous. . .
433
because box dam construction generates local employment and encourages communities to agree on the canal blocking. Also, the targeted peatland area should not have
been degraded to the extent that flooding is very common or almost continual. Peat
swamp forest species are tolerant of waterlogging and flooding, but this tolerance
also has its limits and if an area has been degraded (e.g., significant subsidence due to
fires and/or biological degradation) to a degree that flooding is prolonged and/or
deep these species may also succumb. Paludiculture should therefore target areas
that are degraded and have little or no tree cover (1–5%) but have only occasional
flooding (Giesen and Sari 2018).
Continued Focus on Dryland Species Most species currently cultivated on
peatland in Indonesia are dryland species such as oil palm, Acacia crassicarpa,
cocoa, Liberica coffee, Hevea rubber, dragonfruit, pineapple, Aloe vera, papaya, and
betel nut, but also a range of other fruit species such as durian (Durio zibethinus),
mango, and so on. These all require at least 40 cm or more drainage (some require at
least 50–60 cm), and some (dragon fruit, pineapple, Aloe) are even species adaptive
to (very) dry conditions (e.g., dragon fruit is a member of the cactus family). Their
cultivation on peatland is well known and provides a steady income, although
eventually this source of livelihood will in most cases disappear once peat subside
to the point that it can no longer be drained by gravity and flooding/waterlogging
becomes an issue. In most Indonesian peatland areas, the latter is not yet evident, and
hence there is very significant reluctance to rewet peatland and switch to unknown
paludiculture species. Also, there are currently few examples of true paludiculture
providing an alternative income and this forms a formidable barrier. Trials
attempting paludiculture often end up being compromised by agencies or NGOs
that would like to try sustainable alternatives, but at the same time do not want to
jeopardize farmer incomes. In these circumstances, rewetting is often only
conducted partially (e.g., GWL at 40 cm below surface) and replanting conducted
with a mix of peatland and dryland species.
Reluctance of Large Plantation Companies Large plantation companies have
made huge investments in plantations based on dryland species, and on infrastructure and processing capacities based on these dryland species. Investments to date by
these companies in alternative species have been minimal and hardly seem adequate
considering what is at stake, i.e. long-term survival of the present business models
operating on peatland.
Landscape Approach Needed Rewetting and paludiculture need to be well
embedded in the landscape, as due to hydrological characteristics of peatlands one
cannot manage a part of a peat dome in isolation. One cannot rewet part of a dome
and expect this to be effective if adjacent areas remain in a drained state, and hence
rewetting must be planned on a landscape level. It must also be carried out within a
brief time, for if it takes several seasons then previous work may end up becoming
undone (e.g., if fires take hold). An example of this is the 18,000 ha of Tahura of OKI
in Jambi, Sumatra, which forms the buffer zone of the threatened Berbak National
14 Tropical Peatland Restoration in Indonesia by Replanting with Useful Indigenous. . .
433