a Fisher’s alpha calculation (Harrison et al. 2011) showed that KMP has slightly
higher vegetation diversity compared to Sebangau, although this might need further
clarification due to sampling limitation.
Since it is widely approved that the vegetation in peatland highly corresponds
with peat thickness, nutrient conditions, and its hydrology characteristics (Graham
et al. 2017; Page et al. 1999), a 28 km line transect survey conducted from the west
(Mentaya River) to the east side (Katingan River) of KMP-PA in 2008 described
how the vegetation composition and structure changed with increasing peat depth
(Darusman 2008). Later surveys in 2011 (Harrison et al. 2011) also confirmed that
the zonation of forest subtypes in KMP-PA is relatively similar with those described
by Page et al. (1999) in Sebangau.
Riverine forest that should have been present near the river was absent due to
prolonged forest utilization. In the shallow peats, mixed-swamp forest with uneven
tall canopy height was found, dominated by typical peat species such as those from
the Dipterocarp family, Myrtaceae, Rhizophoraceae, Sapotaceae, Ebenaceae,
Anacardiaceae, Theaceae, Guttiferae, and Melastomataceae (Darusman 2008;
Harrison et al. 2011). This large belt of mixed-swamp forests extends up to 8 km
from the river edge and is mostly disturbed due to past logging activities. Low pole
forest with a dense Pandanus in the lower forest canopy can be found with
increasing peat depth. Finally, unlike in Sebangau where tall-pole forests were
found in the deepest peat, in KMP, very low pole forests such as savannah can be
found in its peat dome instead, dominated by Tristania sp. and Combretocarpus
rotundatus. This indicates that although the ecosystem of KMP and Sebangau is
similar, they are not identical, considering that the KMP forests tend to be more
minerotrophic compared to Sebangau (Harrison et al. 2011; Husson et al. 2018; Page
et al. 1999). In general, dominant tree species that can usually be found throughout
KMP’s peat swamp forest are from the genus Syzygium, followed by Tetractomia
tetrandra, Diospyros cf. evena, Shorea teysmanniana, Tetramerista glabra, and
Stemonurus scorpioides, while the larger trees are dominated by Diospyros
bantamemsis, Tristaniopsis spp., Campnosperma coriaceum, Litsea cf. rufo-fusca,
Horsfieldia crassifolia, Syzygium spp., and Tetractomia tetrandra (Harrison et al.
2011).
While logging alters forest composition and structure due to gap creations, the
occurrence of fires, especially frequent and intense fires, will result in high risk of
deforestation. Our forest regrowth monitoring developed on three transects (each
transect was 220 m long) suggested that although this site was completely covered
by ferns and shrubs (such as Stenochlaena palustris and Cyperus rotundus), in the
absence of remnant trees due to frequent fire incidences, new recruitments can still
emerge. Three years after the fire, the area was not only dominated by pioneer
species such as Melaleuca leucadendron, Melicope lunu-ankenda, Syzygium sp., and
Macaranga pruinosa, but the more generalist species such as Alstonia scholaris,
Ficus benjamina, and Nephelium mangayi also started to grow. Surprisingly,
Combretocarpus and Cratoxylum species that frequently appear after fires
(Blackham et al. 2014; Graham et al. 2017; Shiodera et al. 2016) were absent in
our observation (internal data, unpublished).
390
T. Darusman et al.
higher vegetation diversity compared to Sebangau, although this might need further
clarification due to sampling limitation.
Since it is widely approved that the vegetation in peatland highly corresponds
with peat thickness, nutrient conditions, and its hydrology characteristics (Graham
et al. 2017; Page et al. 1999), a 28 km line transect survey conducted from the west
(Mentaya River) to the east side (Katingan River) of KMP-PA in 2008 described
how the vegetation composition and structure changed with increasing peat depth
(Darusman 2008). Later surveys in 2011 (Harrison et al. 2011) also confirmed that
the zonation of forest subtypes in KMP-PA is relatively similar with those described
by Page et al. (1999) in Sebangau.
Riverine forest that should have been present near the river was absent due to
prolonged forest utilization. In the shallow peats, mixed-swamp forest with uneven
tall canopy height was found, dominated by typical peat species such as those from
the Dipterocarp family, Myrtaceae, Rhizophoraceae, Sapotaceae, Ebenaceae,
Anacardiaceae, Theaceae, Guttiferae, and Melastomataceae (Darusman 2008;
Harrison et al. 2011). This large belt of mixed-swamp forests extends up to 8 km
from the river edge and is mostly disturbed due to past logging activities. Low pole
forest with a dense Pandanus in the lower forest canopy can be found with
increasing peat depth. Finally, unlike in Sebangau where tall-pole forests were
found in the deepest peat, in KMP, very low pole forests such as savannah can be
found in its peat dome instead, dominated by Tristania sp. and Combretocarpus
rotundatus. This indicates that although the ecosystem of KMP and Sebangau is
similar, they are not identical, considering that the KMP forests tend to be more
minerotrophic compared to Sebangau (Harrison et al. 2011; Husson et al. 2018; Page
et al. 1999). In general, dominant tree species that can usually be found throughout
KMP’s peat swamp forest are from the genus Syzygium, followed by Tetractomia
tetrandra, Diospyros cf. evena, Shorea teysmanniana, Tetramerista glabra, and
Stemonurus scorpioides, while the larger trees are dominated by Diospyros
bantamemsis, Tristaniopsis spp., Campnosperma coriaceum, Litsea cf. rufo-fusca,
Horsfieldia crassifolia, Syzygium spp., and Tetractomia tetrandra (Harrison et al.
2011).
While logging alters forest composition and structure due to gap creations, the
occurrence of fires, especially frequent and intense fires, will result in high risk of
deforestation. Our forest regrowth monitoring developed on three transects (each
transect was 220 m long) suggested that although this site was completely covered
by ferns and shrubs (such as Stenochlaena palustris and Cyperus rotundus), in the
absence of remnant trees due to frequent fire incidences, new recruitments can still
emerge. Three years after the fire, the area was not only dominated by pioneer
species such as Melaleuca leucadendron, Melicope lunu-ankenda, Syzygium sp., and
Macaranga pruinosa, but the more generalist species such as Alstonia scholaris,
Ficus benjamina, and Nephelium mangayi also started to grow. Surprisingly,
Combretocarpus and Cratoxylum species that frequently appear after fires
(Blackham et al. 2014; Graham et al. 2017; Shiodera et al. 2016) were absent in
our observation (internal data, unpublished).
390
T. Darusman et al.