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Peatland fish of Sebangau, Borneo: Diversity, monitoring and conservation

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Tropical peat swamp forests provide important ecosystem services, ranging from carbon storage and fire prevention to fish provision. In the Sebangau catchment of Central Kalimantan, Indonesia, we completed the first detailed spatial and temporal assessments of local fish biodiversity in peat swamp forest and blackwater river habitats. Monthly environmental and fish data were collected over a 15-month period in both riverine and forest habitats. This resulted in a species list of 55 species from 16 different families. Species richness in the river was almost 1.5 times higher than in the forest, probably due to the sampling methods and trap selectivity. Average monthly river fish catches were negatively correlated with average monthly river depth. River fish surveys were conducted pre-and post-fire in 2015, with results showing increased river acidity and reduced fish catches post-fire. The fish and environmental data presented form a baseline for future monitoring projects and highlight a previously overlooked potential impact of fire on local biodiversity in Indonesia, namely that fire is likely to have negative impacts on the sizes of fish populations and catches. There are direct implications for human communities that depend on fishing for their livelihoods. Because peatlands and their rivers face continued human disturbance and degradation, assessments of fish biodiversity and water quality are of high priority.
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Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
1
Peatland fish of Sebangau, Borneo: diversity, monitoring and conservation
S.A. Thornton1,2, Dudin2,3, S.E. Page1,2, C. Upton1 and M.E. Harrison1,2
1School of Geography, Geology and the Environment, University of Leicester, UK
2Borneo Nature Foundation, Palangka Raya, Central Kalimantan, Indonesia
3UPT LLG CIMTROP, University of Palangka Raya, Central Kalimantan, Indonesia
_______________________________________________________________________________________
SUMMARY
Tropical peat swamp forests provide important ecosystem services, ranging from carbon storage and fire
prevention to fish provision. In the Sebangau catchment of Central Kalimantan, Indonesia, we completed the
first detailed spatial and temporal assessments of local fish biodiversity in peat swamp forest and blackwater
river habitats. Monthly environmental and fish data were collected over a 15-month period in both riverine
and forest habitats. This resulted in a species list of 55 species from 16 different families. Species richness in
the river was almost 1.5 times higher than in the forest, probably due to the sampling methods and trap
selectivity. Average monthly river fish catches were negatively correlated with average monthly river depth.
River fish surveys were conducted pre- and post- fire in 2015, with results showing increased river acidity and
reduced fish catches post-fire. The fish and environmental data presented form a baseline for future monitoring
projects and highlight a previously overlooked potential impact of fire on local biodiversity in Indonesia,
namely that fire is likely to have negative impacts on the sizes of fish populations and catches. There are direct
implications for human communities that depend on fishing for their livelihoods. Because peatlands and their
rivers face continued human disturbance and degradation, assessments of fish biodiversity and water quality
are of high priority.
KEY WORDS: blackwater fish, fire, Kalimantan, livelihoods, peat swamp forest
_______________________________________________________________________________________
INTRODUCTION
Due to the characteristics of the blackwater aquatic
habitats associated with tropical peat swamp forest
(PSF), i.e. high acidity, high content of dissolved
organic matter and low nutrient content, Indonesia’s
peatland rivers provide habitat for unique
assemblages of fish species that often exhibit high
endemism (Ng et al. 1994, Noor et al. 2005). In
peatland areas such as those in lowland Central
Kalimantan, fishing is usually one of the main
sources of livelihood for communities living beside
the blackwater rivers (Lyons 2003, Chokkalingam et
al. 2007). However, with ever-increasing human
populations, alarming deforestation rates e.g. in
Indonesia, and ongoing aquatic pollution and habitat
degradation, the prognosis for freshwater aquatic
habitats throughout Asia is a matter of growing
concern (Dudgeon 2000, Giam et al. 2012). There
have been few studies of fish in SE Asia’s peatlands,
but the one by Giam et al. (2012) found that 77 % of
fish species are likely to become extinct in Sundaland
if deforestation of PSF continues, with Central
Kalimantan being most heavily impacted. There are
severe implications for these wetland ecosystems, as
well as for the local communities that depend on PSF
and its associated aquatic habitats for their
livelihoods. Therefore, it is vital to better understand
these wetland habitats and their fish populations
alongside their importance for community
livelihoods and cultures, with the aim of finding ways
to conserve and promote biodiversity, and
specifically fish biodiversity, in conjunction with
community development.
The results presented in this article arise from a
broader interdisciplinary project that investigated
values related to fishing and the importance of fish
for local human communities in the Sebangau river
catchment (Thornton 2017). Here we focus on fish
species diversity, a comparison of fish populations in
forest and riverine habitats, and how the species
composition of PSF fish populations relates to habitat
type and abiotic conditions. We aim to provide
important baseline data to support future peatland
fish monitoring in the Sebangau and elsewhere.
METHODS
Study site
The Sebangau Forest (Figure 1) is centred on the
Sebangau River and is bordered by the Katingan River
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
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Figure 1. Below: map of the study area, showing Sebangau National Park and the Sebangau River.
Above: detailed map of river and forest fish trap locations. Forest trap placements in canals are shown with
red markers, and placements beside fallen trees with (green) tree markers. An example route is indicated in
yellow. Maps from and edited in Google Earth, Image CNES/Astrium, 2016.
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
3
to the west and the Kahayan River to the east. The
Sebangau River is a mid-sized blackwater river that
arises from the swamp (in contrast to all the main
rivers in the area, which rise in the hills) and runs
through the Sebangau catchment for about 150 km to
its mouth on the Java Sea coast (Tachibana et al.
2006) (Figure 1). Blackwater rivers like the Sebangau
typically have low quantities of suspended matter,
high amounts of humic acids (giving the water a
brownish-reddish colour that can look black in
certain light conditions) and a pH ranging from 4 to
5 (Ríos-Villamizar et al. 2014). The Sebangau Forest
is characterised by a dome-shaped ombrogenous
peatland with thick peat and low topographic
elevation (Page et al. 1999). The forest experiences
flooding for some months of the year during the wet
season, with resulting standing water pools. There are
also small canals in the forest which were previously
dug and used during the logging years
(approximately 19972004) to transport timber out of
the forest. The Sebangau peat formation is the oldest
known in SE Asia - approximately 26,000 years old
(Page et al. 2004) - and has a maximum thickness of
13 m (Page et al. 1999, Weiss et al. 2002). The area
of the Sebangau Forest selected for the fish
community surveys was the Natural Laboratory of
Peat Swamp Forest (NLPSF), which is managed by
the Center for International Cooperation in
Sustainable Management of Tropical Peatland (UPT
LLG-CIMTROP) at the University of Palangkaraya.
This study site was chosen due to the long history of
PSF research arising from collaboration between the
Borneo Nature Foundation (BNF) and UPT LLG-
CIMTROP.
Fish sampling
Sampling in the Sebangau River was conducted from
September 2014 to December 2015, and in the
Sebangau Forest from February 2015 to July 2015.
The sampling period was shorter in the forest due to
insufficient above-surface water depth to set traps
during the dry-season months (a minimum of 5 cm
water depth was needed). Many types of fishing gear
have been developed by fishing communities around
the world, but relatively few have been adopted for
the purposes of research and management (Portt et al.
2006). We employed local fish trapping methods
(Dayak names in italics), using tampirai traps baited
with a mixture of tempeh (fermented soya bean) and
terasi (fermented shrimp paste). Tampirai traps are
rectangular wire mesh traps with two (inner and
outer) tapering mouths, which allow fish to enter the
trap but not to escape (Figure 2). These traps are in
regular use by local communities in the Sebangau
area because of their reported effectiveness. The bait
Figure 2. Tampirai trap used in this study.
mixture used for the fish surveys is also commonly
used by local fishermen and was recommended by
them for use in this project. Following an initial trial
of various locally available traps (bottle trap, bamboo
trap and two different sizes of wire traps; Figure 3), a
tampirai trap with mesh size 0.6 cm and dimensions
38 × 89 cm was chosen because it could trap a wider
variety of fish species and fish sizes than other locally
available trap types. This was also found by
Worthington (2016), who compared the traps used in
this study with other locally available traps not
covered by the original trial survey. Worthington
tested the larger tampirai used in this survey along
with the pangilar (similar shape to tampirai, with
dimensions 100 × 80 × 80 cm and mesh size 2 cm),
the smaller rattan pangilar (28 × 33 × 33 cm, mesh
size 2.5 cm) and a buwu (cylindrical trap 140 cm
long, circumference 60 cm, with a double set of
conical mouths) made of wire with mesh size 1 cm).
The tampirai gear not only caught the most varied
fish species assemblage, but also had the lowest
species selectivity (where selectivity is the inverse of
diversity). The tampirai traps (with mesh size 1 cm)
are, however, selective against smaller fish and will
not effectively sample fish guilds that include other
smaller species. Therefore, this study focused only on
the larger fish species that could be trapped using
these methods.
When setting the traps, the bait was rolled into a
small ball and put into a wire holder that was attached
to the inside of the trap. On every sampling day the
bait was (removed and) replaced, whether or not it
had been eaten, in order to minimise negative impacts
on captures resulting from bait predation and loss.
Twenty traps were set in the river and 20 in the
forest (see the detailed map in Figure 1). Sampling
took place every month, resulting in 13 months data
for the river and six months’ data for the forest. Each
sampling campaign involved five days of trapping
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
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Figure 3. Fish trap types tested in our initial trial. Top left: a bottle trap similar to the one tested (image from
Tarka Challenge 2012); bottom left: a bamboo buwu trap; and right: wire tampirai traps in two different
sizes.
(traps were set, then retrieved the following day and
set again following data collection) in each location
per month. The sampling strategy for each location
was chosen to balance sampling frequency and
feasibility. For the river surveys, 20 traps were
deployed on alternate sides of the river at 400 m
intervals over a 7 km stretch (Figure 1). Trap 1 was
located at latitude 2° 17' S, longitude 113° 52' E, and
Trap 20 was downstream at 2° 18' S, 113° 56' E. The
forest surveys involved sampling of two different
open water habitats. Fourteen traps were set on the
sides of two canals (maximum width 2.5 m;
Figure 4), with the traps located 50 m apart from each
other. Six traps were placed in tip-up pools (formed
when shallow-rooted trees are uprooted; Dommain et
al. 2015, Figure 4) spread across the study area.
These traps were set towards the edges of the pools
with the entrance facing the middle of the pool, as
recommended by local fishermen.
The forest sampling locations were chosen to
maximise the area over which sampling took place
while keeping it practically possible to check all of
the traps in one day. Due to the physical difficulty of
walking in PSF, especially during the wet season, the
trapping area covered in the forest was smaller than
that covered along the river. Surveying the traps was
facilitated by designing an efficient 4 km walking
route through the forest using an existing permanent
transect system (Figure 1). In the river, the traps were
set at approximately mid-depth in the water column.
We recognise that this depth will vary between
locations, and future research could test whether trap
depth (its vertical location in the water column) has
an impact on the numbers and species of fish trapped.
Our chosen approach followed advice from local
fishermen on the placement most likely to trap the
widest variety of species, and we avoided placing
traps either at the very bottom of the water
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
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Figure 4. Traps in the forest were set in previous logging canals (above) and tip-up pools (below).
column or at the top. The traps were aligned with the
opening facing upstream to further discourage fish from
escaping.
In both river and forest habitats, traps were set the
day before the first sampling day. Throughout each
monthly sampling campaign, each trap was then
checked and emptied daily (usually between ~ 08.00
and 14.00 hours, although this could vary depending
on the number of fish trapped). On emptying the trap,
all fish were identified and their standard length (SL,
measured from the most anterior extremity, mouth
closed, to the base of the median tail fin rays)
recorded to the nearest mm. If more than 100 fish
were caught in a trap, a sample of 20 individuals of
each species was measured and the rest counted. Fish
identification was performed visually using Kottelat
& Whitten (1993), subsequently checked using
online resources (e.g. FishBase; www.fishbase.org),
and then verified following consultation with
taxonomic experts. In some cases it was only possible
to identify fish to genus level in the field, e.g. Clarias
spp. (walking catfish). Care was taken to avoid
stressing the fish by placing them in buckets of water
after collection, keeping the buckets covered to
reduce the risk of overheating, and returning the fish
to the water immediately after measurement. Any
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
6
mortality (i.e. whether the fish was alive or dead
when counted) was noted.
There was occasional opportunistic sampling of
fish in that, when a fish species which had not been
trapped was observed in the river or forest, it was
collected with a hand net to add to the species list.
Opportunistic sampling led to four species being
added to the list, namely Rasbora kalbarensis and
Kottelatlimia pristes along with two Mystus species.
Water sampling
Environmental measurements were taken either
during each trapping site visit or once a month.
Daily environmental measurements were water
temperature, pH, dissolved oxygen (DO) and Secchi
disk depth as a proxy for water turbidity (river only)
(Table 1). Monthly measurements were water depth,
width, flow rate (forest only) and nutrient levels
(Table 1). On the final day of sampling of each
month, surface water samples were collected from
the sampling locations and on the same day were
taken to a refrigerator and kept at 4 °C if storage prior
to analysis was needed. Chemical analysis of the
water samples was performed at the University of
Palangka Raya laboratory using Atomic Absorption
Spectrophotometry (AAS; Spectra 30, Nordson,
Duluth, USA) following standardised procedures.
Analysis for P followed the ascorbic acid method of
Eisenreich et al. (1975) after Murphy & Riley (1962)
(see Sulistiyanto 2005 for further details), NO2
analysis was carried out using the Griess test (a
standard procedure for testing nitrite in water, see
Sulistiyanto 2005), and NO3 analysis followed Yang
et al. (1998). Secchi disk depth data were collected
only from February 2015 onwards, after the digital
turbidity meter that was used previously failed.
There were some differences between river and
forest habitats in the types of environmental data that
could be gathered. Secchi disk depth data could not
be obtained in the forest because the pools and canals
were too shallow. Flow measurements were not taken
in the river, as they were impossible to perform
accurately from a boat, but surface water flow rate in
canals in the forest was measured using a stopwatch
and a floating ping-pong ball. A previous study by
Tachibana et al. (2006) reported that the water
discharge rate of the Sebangau River varied greatly
between dry and wet seasons, ranging from a
maximum of 50 m3 s-1 during wet season months to a
minimum of 5 m3 s-1 in dry season months.
Table 1. Summary of the environmental variables, methods of measurement and frequency.
Method
Frequency
Measuring tape with weight attached
Monthly
Measuring tape or GPS
Monthly
pH meter or the temperature function on the ProODO YSI
Digital meter1
Daily
Ping-Pong ball and measuring stick2
Monthly (Forest only)
Stick meters (Hanna HI-98127 or equivalent)3
Daily
ProODO YSI Digital meter1
Daily
Secchi disk4
Daily
Laboratory analysis; see text for details of methods.
Monthly
1 This is a standard method, as used by e.g. Bodamer & Bridgeman (2014), Hedström et al. (2017), Geeraert
et al. (2017).
2 A known technique, see e.g. Petr (1970), Ikomi et al. (2005).
3 Standard method using portable pH meters, see e.g. Li & Li (2009), Aziz et al. (2012), Dodemaide et al.
(2018).
4 A known technique, see e.g. Preisendorfer (1986), Sandén & Håkansson (1996).
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
7
Post-fire data collection
Indonesia was hit by extensive forest and peatland
fires in 2015, when a strong El Niño-related drought
combined with forest disturbance and widespread
peatland drainage made 2015 the worst fire season
since 1997 (Chisholm et al. 2016). In Kalimantan the
2015 fire season began in August (Field et al. 2016),
with conditions worsening until the fires were
extinguished at the onset of the wet season in
November. Fish and water surveys were discontinued
in October due to health and safety concerns, then re-
started in November and December when the start of
the wet season led to improved air quality and made
fieldwork conditions safe once more. Owing to
resource restrictions, the post-fire surveys were
conducted over three days (in comparison to the usual
five days of sampling before the fires). Data were
collected on the in-situ environmental variables (i.e.
DO, pH, water temperature, depth etc.) but no
nutrient analyses were undertaken.
Data analysis
To standardise captures for data analysis and
comparisons, fish catch per unit effort (CPUE) was
calculated using the following formula (Merilä
2015):
𝐶𝑃𝑈𝐸 = 𝑁𝑐𝑎𝑡𝑐ℎ
(𝑁𝑡𝑟𝑎𝑝𝑠× 𝑁𝑛𝑖𝑔ℎ𝑡𝑠) [1]
where Ncatch = number of fish trapped, Ntraps = number
of traps set, Nnights = number of nights for which traps
were set. This allows the catch data to be compared
between times when the number of trapping days
varied (e.g. pre- and post-fire, and if a trap went
missing).
Due to the selective nature of any trapping gear,
and the heterogeneity of the river and the forest
habitats, it is possible that the ‘catchability’ and/or
species composition of the fish populations in the two
habitats differs. Knowing whether this is the case is
very challenging in practice. To understand the
potential number of species that may have been
missed by our surveys, estimated species richness
was calculated. EstimateS computes non-parametric
asymptotic species richness estimators: Chao-1 and
ACE using abundance data, ICE using incidence data
(presence data) and Chao-2 using replicated
incidence data (as samples were replicated over
several days) (Gotelli & Colwell 2010). As
recommended by Colwell (2013), the classic instead
of the bias-corrected option was used for these
calculations, as Chao’s estimated coefficient of
variation for Abundance distribution and CI for
Incidence distribution was high (> 0.5). Therefore,
the larger Chao-1 Classic and ACE are reported as
the better estimates of abundance-based richness, and
the larger Chao-2 and ICE as better estimates of
incidence-based richness (see Colwell 2013 for
detailed descriptions of these estimators and
procedures).
Percentage fish mortality was calculated as the
percentage of fish that were dead when the traps were
emptied. To explore species turnover over time,
Jaccard’s species similarity between the months was
calculated for both habitats and between habitats.
As data collection in the forest ran for only six
months (FebruaryJuly 2015), correlation or
regression analyses were not carried out between
variables due to low sample size. Correlation
analyses are presented for the river data. We
acknowledge that the spatial and temporal sampling
of the traps are not statistically independent of each
other. Achieving completely independent samples
was not practically feasible. Therefore, we
recommend continued long-term data collection
which will allow more in-depth and complex
statistical analyses to be completed in the future.
RESULTS
Over the course of 1,300 river survey trap nights (20
traps × 5 days per month × 13 months), a total of
55,147 fish of 38 species were trapped and counted,
with 22,917 fish measured. In the forest, a total of
3,938 fish of 27 species were trapped and counted
over 600 trap nights (20 traps × 5 days per month ×
6 months), with 3,905 fish measured. Four other
species, namely: Rasbora kalbarensis, Kottelatlimia
pristes and two Mystus species, were trapped
opportunistically at the mouth of a canal by the river.
From published literature, some other fish species are
also known to be present in the Sebangau area: Betta
hendra, Silurichthys ligneolus, Hemirhamphodon
tengah (Page et al, 1997, Ng & Tan 2011, Schindler
& Linke 2013). Hemirhamphodon chrysopunctatus
was seen in the river but not trapped. These species
are examples of those missed by our trapping method
due to their small body size and their feeding
behaviours (Betta spp. are small, slow swimming air
breathers while Hemirhamphodon spp. are surface
feeders and thus not attracted to the bait in fishing
traps). A further species, Anabas testudineus, was
trapped during a pilot survey in the forest in
September 2014, whilst Wallago leeri is reported to
be present in the Sebangau River by local fishermen.
These examples illustrate that other species are likely
to be present in the area but were not collected by our
sampling methods. With these additions, our final
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
8
species list comes to 29 species in the forest and 41
in the river, producing a total of 55 species from 16
families in the Sebangau study area (Table A1 in
Appendix). Abundances of each species trapped for
each month and habitat are presented in Table A2.
The estimated species richness in forest and river
indicated that the forest would have fewer species
than the river (Figure 5), and this was supported by
the survey data. On this basis we detected 7594 %
of the estimated species richness of the river (average
of 47 species estimated), while the trapping in the
forest captured more species than were estimated to
be present across all estimators (29 species were
recorded, with an average estimation of 26 species
between ACE, ICE and Chao estimates). In both the
river and the forest, ACE estimators were the most
conservative, with the Chao-1 estimator always
giving the highest estimated species richness. For the
forest estimates there is good agreement between all
richness estimators (minimum = ACE with 25.69,
maximum = Chao-1 with 25.99) while the river
estimators show higher variance (minimum = ACE
with 43.57, maximum = Chao-1 with 54.99).
The river fish assemblage was dominated by
Osteochilus spilurus (32 % of river catch),
Sphaerichthys acrostoma (20 % of river catch),
Desmopuntius foerschi (11 % of river catch), Mystus
olyroides (9 % of river catch) and Rasbora
cephalotaenia (8 % of river catch), while the forest
was dominated by Rasbora kalochroma (52 % of
forest catch), Betta anabatoides (13 % of forest
catch), Encheloclarias tapeinopterus (8 % of forest
catch), Channa gachua (5 % of forest catch) and
Belontia hasselti (5 % of forest catch). The total
number of species trapped in both the river and the
forest was 17, which constitutes 45 % of the total
species count for the river and 63 % for the forest. In
the forest the remaining 37 % included species that
are usually found in forest streams and standing water
habitats (e.g. Betta anabantoides, Rasbora
kalochroma, Clarias meladerma, Anabas
testudineus).
With regard to species turnover over time, the
species similarity in the river decreased over the
transition between the dry and wet season (October-
November 2014), and then had a general trend of
increasing throughout the wet season (Figure 6A).
The greatest turnover of species in the river occurred
in NovemberDecember 2014 when there was a
species similarity of 42 %. This corresponds with a
decrease in species richness during these months
(Figure 7) and, therefore, the increase in species
turnover can be explained by fewer species being
caught at the onset of the wet season. For the forest,
there was a relatively high species similarity of 70 %
Figure 5. Estimated species richness in the
Sebangau Forest and River using ACE [grey], ICE
[diagonal line], Chao1 [dots] and Chao2
[horizontal line], compared to final species list
numbers [black column].
in FebruaryMarch 2015, with an increase in species
similarity to 79 % in MarchApril (thereby lower
species turnover). After March, there was a
consistent decrease in species similarity (i.e.
increasing turnover of species) until the end of the
forest sampling (in July). The greatest species
turnover in the forest, with a similarity of 53 %, was
between June and July. This corresponds to a
decrease in species richness from 15 species trapped
in June to 8 species in July (Figure 7). The calculated
Jaccard’s similarity values between months for the
river were not significantly correlated to any of the
environmental variables (Table 2). Species richness
showed no statistically significant correlation with
any of the environmental variables. There was a
positive correlation with river water temperature,
although this is likely to be an artefact of the small
sample size (Table A3). Correlation analyses were not
run for the forest dataset due to the small sample size.
Comparing the species similarity values between
the two habitats in FebruaryJuly 2015 (Figure 6b),
there was consistently low similarity, with similarity
never increasing above the maximum similarity value
of 21 % found in May 2015. The lowest similarity
between the two habitats occurred in July with a
value of only 7 %. Statistical analysis comparing
species similarity to environmental trends was not
done due to small sample sizes.
A consideration of changes in fish body size (SL
in mm) over time demonstrated large variations in
mean body size (M) between sample months
(Figure 8). Overall, there was no significant
difference in the average body sizes of fish trapped
in the river (M = 63.1 mm, SD = 9.3) and forest
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
9
A
B
Figure 6. A: Species turnover in the river (black) and forest (grey) over time, calculated as Jaccard’s
similarity coefficient between each month. The grey box indicates the approximate duration of the wet
season. B: Species similarity between the forest and river surveys from February to July 2015, calculated as
Jaccard’s similarity coefficient.
Figure 7. Species richness over time in the river
(black) and forest (grey). The grey boxes indicate
the approximate duration of the wet season, and
the orange box the approximate fire season
(August to end of October).
(M = 64.6 mm, SD = 5.4); t (15) = -0.47, p = 0.644. At
the change from the dry season to the wet season
(October to November 2014), the average body size
of fish trapped in the river increased from
approximately 62 mm in October to 86 mm in
November. It then decreased back to 61 mm in
December with fluctuation around a generally
decreasing trend until September 2015. In the forest
there were similar fluctuations, with the greatest
decrease in body size occurring with the onset of the
dry season between June (average body size 72 mm)
and July (average body size 56 mm).
Table 2. Statistical analysis (Spearman rho, rs) or
Pearson’s product correlation (PPC) if indicated,
between Jaccard’s species similarity (JS) in the river
over time compared to the changes in environmental
variables; n = 12, p > 0.05 in all cases.
Change in DO
-0.446 (PPC)
Change in pH
-0.112 (PPC)
Change in water depth
-0.544 (PPC)
Change in temperature
0.256 (PPC)
Change in rainfall
-0.455 (rs)
Change in P
0.035 (rs)
Change in NO2
-0.476 (rs)
Change in NO3
-0.350 (rs)
The river had an average CPUE of 42.2 (from
September 2014 to September 2015), compared to
6.1 in the forest (from February 2015 to July 2015;
over the same time period, the river had an average
CPUE of 45.93) (Mann-Whitney U = 0.003, n = 19,
p = 0.003) (Figure 9 plots the CPUE on a log10 scale).
In the forest, the CPUE decreased between June and
July with the onset of the dry season. In the river,
there was a large increase in CPUE between June
(CPUE = 2.03) and July (CPUE = 41.2) (Figures 9
and 10). The CPUE in the river was negatively
correlated with average river depth (rs = -0.571,
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
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n = 13, p = 0.041) (Figure 10, Table A3). While there
was no statistically significant correlation between
monthly CPUE and turbidity (Table A3) this could be
due to a small sample size (Secchi disk measurements
were only collected from February onwards).
Considering daily rather than monthly CPUE data (in
order to increase the sample size) did result in a
modest negative correlation between CPUE and
average daily Secchi disk depth (rs = -0.479,
p = 0.002, n = 38), suggesting that fewer fish were
trapped in the river with increasing water clarity.
More long-term data collection is recommended to
better explain the relationship between fish catch and
water turbidity.
The river was deeper and wider than the water
bodies in the forest, with an average water depth of
5.4 m in the river and 0.4 m in the forest (Table 3).
The average water body width in the river was 30 m
and in the forest 2.4 m. Both water depth and width
varied a lot in both habitats, particularly for the river
(Table 3). Over the time of the surveys, there was an
increase in water depth in the river following the
onset of the wet season in OctoberNovember 2014
Figure 8. Variation in average body size over time,
measured as Standard Length (mm) of fish trapped
in the river (black) and forest (grey). The grey
boxes indicate the approximate duration of the wet
season, and the orange box the approximate fire
season (August to end of October).
Figure 9. Variation in monthly Catch per Unit
Effort (CPUE) over time, plotted on a log10 scale,
in the Sebangau River (black) and Forest (grey).
The grey boxes indicate the approximate duration
of the wet season, and the orange box the
approximate fire season (August to end of
October).
Figure 10. Variation in river CPUE (black) and
water depth (m) (grey) over time. The grey boxes
indicate the approximate duration of the wet
season, and the orange box the approximate fire
season (August to end of October).
Table 3. Average water depth (m) and water body (WB) width (m) in the river and the forest, with minimum
(Min.) and maximum (Max.) measured. Standard deviation indicated in brackets.
Location
Average water depth
Min.
Max.
Average WB width
Min.
Max.
River
5.4 (± 1.48)
1.5
8.7
30.0 (± 18.73)
3.3
130.0
Forest
0.4 (± 0.17)
0.1
0.9
2.4 (± 1.68)
0.3
12.5
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
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© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
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(Figure 11, water depth graph). Water depth then
remained stable between February and June before
decreasing from June through until September 2015
with the onset of the dry season. Water depth in the
forest decreased constantly from February through to
July 2015. In the river the average monthly water
depth was positively correlated with average DO
levels (rs = 0.718; Table A3).
There were greater fluctuations in DO levels in the
river compared to the forest (Figure 11). Forest
Figure 11. Environmental variables in the river (black) and forest (grey). Error bars indicate standard
deviation where appropriate. The grey boxes indicate the approximate duration of the wet season, and the
orange box the approximate fire season (August to end of October).
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
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© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
12
values fluctuated between monthly averages of 1.2
and 1.7 mg L-1 (February to July), whilst river values
fluctuated between 2.9 and 3.6 mg L-1 over the same
months. Across all months, the river had the lowest
average DO value in October 2014 (0.8 mg L-1) and
the highest average values between December 2014
and June 2015 (maximum of 3.6 mg L-1 in
December). These higher values correspond with the
wet season, which ran from January to April/May,
with a positive correlation between amount of rainfall
(and hence higher river flow rates, Tachibana et al.
2003) and river DO (rs = 0.718, n = 13, p = 0.006).
There was a negative correlation between average
monthly river water temperature and DO levels
(PPC r = -0.589, n = 13, p = 0.034). Also, while the
forest exhibited lower water temperatures in general
compared to the river, there was not a corresponding
higher DO level in the forest, with DO levels
consistently lower in the forest compared to the river
between February and July 2015 (Figure 11).
Following the fires in 2015, there was an almost
five-fold increase in acidity of the water in the
Sebangau River, pH dropping from a pre-fire mean
of 3.88 (n = 100) in September to 3.20 (n = 60) in
November at the end of the fire season. The latter
measurement was also the lowest pH value obtained
during the whole river sampling period (Figure 11).
This drop in pH corresponded with a decline in fish
CPUE in the river from 18.21 in September to 4.02 in
November.
Nutrient levels also showed temporal variations.
At the onset of the wet season there was a spike in P
levels in the river, which rose from 0.03 mg L-1 in
October to 0.09 mg L-1 in November, and then a
decreasing trend throughout the rest of the year
(Figure 12). NO3 levels showed a similar spike but in
Figure 12. Environmental variables (NO2, NO3, total P and rainfall) in the river (black) and forest (grey).
Error bars indicate Standard Deviation where appropriate. The grey boxes indicate the approximate duration
of the wet season, and the orange box the approximate fire season (August to end of October).
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
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© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
13
this case over the months of November and
December, when levels increased from 0.14 mg L-1
to 0.60 mg L-1. NO2 levels were variable with a
general increase over time during the wet season
(from 0.02 mg L-1 in November to 0.05 mg L-1 in
June) and a subsequent decrease during the dry
season (from 0.04 mg L-1 in July to 0.03 mg L-1 in
September).
For the river, percentage fish mortality was
calculated for each month of trapping (Figure 13). In
October 2014, a maximum level of 50 % fish
mortality occurred. This dropped to less than 10 %
for much of the wet season when DO levels were also
higher, but there was an increasing trend of mortality
after the onset of the dry season in July, which
corresponded with decreasing DO levels and was
confirmed by a strong negative correlation between
average DO (mg L-1) and mortality rate
(PPC r = -0.754, n = 13, p = 0.003). Mortality rate
showed no correlation with any other environmental
variables that were measured.
DISCUSSION
Our results provide an initial picture of the
composition of this Bornean peatland fish
community and how it changed over the year-long
sampling period in conjunction with various
environmental variables. These data establish a
valuable baseline for future monitoring of forest and
river fish in the Sebangau peatland and a comparison
for studies conducted in other peatlands throughout
the region. The authors recognise that the sampling
methods will be selective against certain species and
that our methods sample a specific fish guild that is
large enough to be trapped and is attracted to the bait
used. However, methods used to exhaustively sample
fish can be intensive and destructive to fish habitats
and also require the collection and preservation of
many specimens. This can be argued to be counter to
conservation best practice, particularly as the
population sizes of species and their distributions in
PSF habitats are poorly understood. Therefore, we
propose that the tampirai trapping method should be
used for future monitoring.
Whilst the survey methods used in this study may
not have been exhaustive, the resulting list of 55
species is longer than those presented by Page et al.
(1997) who reported 34 fish species in the Sebangau
River and Forest, and by Haryono (2012) who
reported only eleven species in the Sebangau River.
One of the eleven species reported by Haryono
(2012) (Hemibagrus nemurus) was not recorded in
our survey and is likely to have been a mis-
Figure 13. Monthly mortality rate (%; black) and
dissolved oxygen levels (mg L-1; grey) in the
Sebangau River from September 2014 to
September 2015. The grey box indicates the
approximate duration of the wet season and the
orange box the approximate fire season (August to
end of October).
identification of another Bagridae species (Ng 2012).
Haryono (2012) also reports the presence of
Pristolepis fasciata, which is difficult to differentiate
from the species Pristolepis grootii (Froese & Pauly
2017) which was recorded in our survey. Page et al.
(1997) report the presence of both of these species in
the Sebangau; furthermore, they report the presence
of Parosphromenus parvulus, Sphaerichthys
selatanensis (which is difficult to distinguish from
S. osphromenoides as identified in our survey) and
S. vaillanti, as well as Chendol keelini. This indicates
that the species number reported here is likely to
increase with further surveys, and that additional
taxonomic work is needed, for example on species
from the genera Pristolepis and Sphaerichthys. Sule
et al. (2016) recently compiled lists of fish species
recorded in Malaysian PSF. They list 114 species
from North Selangor, 49 from Paya Beriah, 13 from
multiple sites in Johor, 58 from multiple sites in
Pahang, and nine from Pahang and Terengganu. In
Malaysian Borneo, 31 species from 12 families and 40
species belonging to 13 families have been recorded
from peatlands in Sabah and Sarawak, respectively.
Concurring with Sule et al. (2016), most of the species
we captured were from the Cyprinidae family,
followed by Osphronemidae, with equal numbers
from Bagridae and Siluridae. While direct
comparisons are difficult owing to variations in
sampling effort and environmental conditions, the
Sebangau does appear to be confirmed as a notable
area for fish diversity amongst peat swamp forests
since it has the highest fish species richness recorded
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
14
in a Bornean peatland ecosystem to date (55 species).
Furthermore, this is a greater number of species than
has been noted from at least three of the five sites in
Peninsular Malaysia reported by Sule et al. (2016).
With regard to temporal trends of species turnover
it was observed that species similarity in the river
decreased during the transition between dry and wet
seasons and that this corresponded to a decrease in
species richness for these months. Increased rainfall
and river water depth at the onset of the wet season is
likely to lead to decreased ‘catchability’ of the fish
during these months, but as water levels decrease
following the onset of the dry season, there is a
corresponding increase in catchability along with
species richness and turnover.
The higher fish species richness in the Sebangau
River, compared to the forest, could be a
consequence of the larger area encompassed by the
surveys in the river compared to those in the forest.
Water body dimensions are likely to play a role in
fish ‘catchability’ in the two locations, and will also
affect catch sizes and species richness. Predicted
species richness was higher for the river than for the
forest and, while future surveys using a variety of
methods would help to elucidate whether the
difference is real or an artefact of this study, there are
various reasons why we might expect to find more
species in the river compared to the forest. First, with
greater volumes of water, a greater surface area of
land below and to the sides of the water body and a
much wider variation in water flow rates, the river
potentially has a greater number of niches than the
forest. In the forest, water depth imposed a limitation
on the fish surveys, which ceased during the dry
season owing to very low water levels in both pools
and canals. In temperate rivers, Grenouillet et al.
(2004) found that increased stream size was
associated with increased fish species richness
(Gorman & Karr 1978, Taylor & Warren 2001). It is
also well established that water depth influences fish
assemblages in streams (Harvey & Stewart 1991,
Matthews 1998, Carvalho & Tejerina-Garro 2014,
Marion et al. 2015), as deep water is related to
environmental stability (e.g. due to damping of
temperature fluctuations) and allows greater vertical
separation of fish microhabitats (e.g. Baker & Ross
1981, Gorman 1988a, 1988b; D.A. Jackson et al.
2001). Increased habitat stability favours higher
species richness and abundance (Schlosser 1982,
Winemiller et al. 2000, Grenouillet et al. 2004,
Jardine et al. 2015); thus, water depth can play a
significant role in determining habitat diversity and
consequently fish assemblage structure and species
diversity (Sheldon 1968, Evans & Noble 1979,
Schlosser 1982, R.B. Jackson et al. 2001).
In addition, the forest pools and canals had
consistently lower water DO levels compared to the
river. This is probably due to the inherent nature of
the aquatic habitat in peat swamp forests, where DO
levels are kept low due to the high amount of tannins
in the water (from the high organic matter content of
the peat), with the accumulation of decaying organic
matter depleting DO levels. Additionally, there is low
or no water flow (especially in the pools) which
further ensure low levels of DO regardless of the
lower surface temperatures of forest water bodies
(Yule & Gomez 2009). Low concentrations of DO
can make water uninhabitable for certain fish species
(Kramer 1987, Goodman & Campbell 2007, Zhang
et al. 2009, Essington & Paulsen 2010), therefore the
forest is likely to be a more challenging environment
for fish survival compared to the river. This is also
supported by Beamish et al. (2003) who found that
Malaysian peat fish assemblages which were
relatively rich in species and numerical abundance
were associated with habitats offering comparatively
high levels of DO. Additional data collection using
methods to analyse differences in water quality in the
forest and river (e.g. tannin quantities) could further
elucidate these correlations. DO levels will also
depend on mixing of the water caused by turbulence
and water flow, but we were unable to collect data on
these factors for the river. Therefore, further
sampling of these environmental variables is highly
recommended for future research to allow a more
complete evaluation of the differences between the
forest and river environments.
Across all species richness estimators, there was a
clear under-estimation for the forest species, as more
species were trapped than predicted. This could relate
to the aforementioned ‘catchability’ of forest species
which was lower than in the river, i.e. making it
harder to catch new species, but this does not mean
that they were not there. Using a variety of other
sampling methods, such as nets with a smaller mesh
size, could provide further insights into any potential
bias introduced by using traps in the forest compared
to the river. Furthermore, the estimators themselves
are also subject to bias because they all tend to under-
estimate true diversity (O’Hara 2005). The Chao-1
estimator was originally derived as a ‘minimum
asymptotic estimator (Chao 1984), but Gotelli &
Colwell (2010) posit that all other estimators should
be treated as estimating the lower bound on species
richness. Nevertheless, both the survey results and all
the estimated total species richness results indicate
lower fish species diversity in the forest compared to
the river.
Fish mortality was significantly correlated to DO
levels (Figure 13) and to none of the other measured
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
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© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
15
environmental variables. pH in the river increased in
October when there was a spike in mortality rate,
however there was no statistically significant
correlation overall between pH and mortality. Longer
term data collection with larger sample sizes would
allow future detailed analyses of interactions between
environmental variables, CPUE and mortality rates.
Worthington (2016) also concluded that low DO
concentrations during the study period were the main
determinant of high rates of fish mortality. Based on
the correlation between surface water DO levels and
fish mortality, any future fish surveys should take this
into consideration by carrying out preliminary
measurements of surface water DO levels to
determine whether conditions are suitable for setting
traps. Based on our data, the best months for reducing
mortality in trap-based fish surveys were between
November and July (mortality rate 0–17 %), during
which time DO levels were above 1.98 mg L-1. For
future fish surveys, care should be taken when DO
levels fall below this value, and if surveys result in
high rates of fish mortality they should be
discontinued.
Increased water turbidity can have significant
impacts on aquatic ecology, for example by
impairing underwater visibility and, thereby, the
ability of fish that forage by sight to feed (Utne-Palm
2002). It can also cause harm to the respiratory
systems of fish (Kennedy et al. 2004), while short-
term increases in turbidity have been found to lead to
immediate behavioural changes in fish populations
(e.g. Gray et al. 2011 found a significant shift from
fish displaying territorial and courting behaviours to
foraging behaviours in their experiments with Lake
Malawi cichlids). As the difficulty of finding food
increases, fish are likely either to move away from
the impacted area or to prioritise processes other than
feeding to survive. It could therefore be expected that
increasing turbidity, as indicated by decreasing
Secchi disk depths, would lead to lower CPUE, but
the results (when considering daily rather than
monthly measurements) indicate the complete
opposite. More long-term data collection is
recommended to clarify this relationship between
fish catch and turbidity, but we provide some
suggestions as to why this relationship may occur.
Turbidity changes are dependent on both suspended
sediments and organic materials, as well as algae in
the water; thus, the higher fish catches could be due
to there being higher levels of small food items for
the fish in the water at times of greater turbidity.
Additionally, the correlation between daily turbidity
and CPUE may be influenced by the type of fish
species being caught. The fish traps used were
selective against bigger fish, which are likely to be
the bigger carnivorous species, and were more
effective in capturing species of lower trophic levels.
The latter tend to be omnivorous and
planktivorous/algivorous species. Indeed, there was a
dominance of omnivorous fish in the river, with a
high proportion of these being Osteochilus spilurus.
These smaller prey species are more vulnerable to
predation in clearer waters, so during times of lower
water turbidity they may stay close to vegetated areas
and ‘safer’ locations, or may suffer higher predation
levels from other fish. Therefore, catches of these
smaller species are likely to increase during periods
of higher turbidity. The effects of turbidity on fish are
likely to be species-specific and further studies could
usefully elucidate the complex relationships between
fish behaviours and environmental conditions.
CPUE in the river was not correlated with any
environmental variables apart from river depth. This
is a surprising result, as CPUE might be expected to
correlate with DO level, rainfall, temperature or pH.
Rather than ruling out any influence of these
variables, we believe instead that this illustrates the
difficulty of trying to untangle the complex
relationships between fish behaviour and the full
spectrum of habitat factors on the basis of limited
measurements (we gathered data only from the river
surface, for example). Our methods were chosen for
practical reasons and we recommend that, if
resources allow, future monitoring based on the
methods presented here should run alongside more
in-depth and exhaustive studies on the relationships
between fish behaviour and environmental variables.
There were notable temporal variations in nutrient
levels in the river during the study period. The spikes
in nutrient levels at the onset of the wet season are
probably due to increased nutrient runoff from both
the peat dome and the small town of Kereng
Bangkirai (see Figure 1) and its adjacent agricultural
land upstream. The sampling period for nutrient
levels in the forest habitats was too short-term to
determine any seasonal trends (running only from
February to June 2015, n = 5). Continued long-term
monitoring of nutrient levels could help clarify
monthly trends and allow comparisons between
habitats. Furthermore, investigations of the
occurrence and growth of algae is recommended in
order to further explore relationships between
nutrient levels and food availability for algivorous
fish species. Despite being incomplete, the initial
dataset on nutrient levels collected during this study
provides a baseline for future monitoring.
Measurements taken in November and December,
immediately after the end of the 2015 fire season, did
not reveal any statistically significant changes in DO,
water temperature or water turbidity. Fires can
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© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
16
significantly increase sediment loads in peatland
rivers following heavy rainfall, which would be
expected to increase water turbidity (Maltby et al.
1990, Brown et al. 2015). Increased turbidity will
have an impact on both fish and fishing. Indeed, some
authors identify increased turbidity as the greatest
threat to aquatic fauna (Beschta 1990, Beaty 1994,
Rieman et al. 1997, Benda et al. 2003, Meyer &
Pierce 2003). However, the data from this study
showed no significant changes in water turbidity
following the 2015 fires. This could be due to
measurements being taken after there had been
sufficient rainfall to clear the upper reaches of the
Sebangau River of much of its sediment load. Holden
et al. (2012) found that post-fire organic carbon loss
occurs very rapidly (within a few weeks) after fire,
while Moore et al. (unpublished data) found an
immediate post-fire enhancement of dissolved
organic carbon losses from tropical peatlands. Given
that carbon loss is probably linked directly to
sediment transport (Grieve & Gilvear 2008,
Shuttleworth et al. 2014), it is possible that a post-fire
period of enhanced sediment loss and increased
turbidity had already come to an end by the time the
post-fire measurements were made at the start of the
wet season.
There was, however, a significant decrease in
river pH in the post-fire period, which also
corresponded to a drop in CPUE. This result is in
agreement with reports from local fishermen that
post-fire fish catches in the Sebangau river were
extremely poor (Dudin, personal communication
14 Dec 2015). A decrease in river pH could be due to
the fire damaging the soil structure and burning
organic matter (Lyon & O’Connor 2008, Brown et al.
2014), leading to a release of organic acids and other
low-pH substances (Page et al. 2002, Holden et al.
2012, Moore et al. 2013, Jauhiainen et al. 2016).
Likewise, the pH of water in temperate streams can
fall as low as 3 when organic acids are flushed out of
peats after high precipitation events (Rothwell et al.
2005). A decrease in river pH is likely to cause
changes in the behaviour and, potentially, survival of
fish, as pH changes affect the ion and acid-base
regulatory mechanisms in their gills as well as mucus
secretion and gill structure (McDonald 1983, Laurent
& Perry 1991, Kwong et al. 2014). Therefore, a
decrease in pH could either cause local fish mortality
or act as a trigger for fish to migrate to other parts of
the river with more favourable pH levels. The
behaviour and sensitivity to pH fluctuations of the
river and forest fish is a key knowledge gap, as is the
exact geochemical mechanism behind the pH
decrease in the river. The evidence from this study
strongly suggests that the post-fire increase in river
acidity impacted negatively on local fish catches,
which in turn has negative implications for human
livelihoods and wellbeing.
Continued monitoring of fish populations using
the same sample locations as in this study is
recommended in order to acquire longer-term
datasets on fish catches and, hence, on population
trends and water quality. This will facilitate ongoing
evaluation of river health which is vital given the role
that fish and fishing play in providing an important
source of protein and income for local human
communities. Continued research will not only
improve our understanding of aquatic environments
in peat swamp forests, but also the consequences of
environmental changes for human communities. Fish
constitute one of the clearest links between people,
their livelihoods and their environment. In areas with
high dependence on fish for livelihoods, fish research
and conservation projects could provide excellent
opportunities to increase the relevance of
environmental research to local communities and
thus, potentially, to increase local support for
conservation projects.
ACKNOWLEDGEMENTS
Many thanks to the research assistants who supported
this study in the field: Iwan, Ahmad, Krisyoyo,
Karno and Bustani Arifin Unyil. Thanks also to the
Centre for International Cooperation in Sustainable
Management of Tropical Peatlands at the University
of Palangka Raya for their support of the project;
RISTEK for research permissions; plus all BNF staff
and volunteers who assisted with logistics and
fieldwork. Thanks to Hendra Tommy and Dr. Xingli
Giam for their help with fish identification. Finally,
thanks to The Rufford Foundation and the
International Peatland Society for their vital funding.
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Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
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Submitted 21 Nov 2017, final revision 07 Oct 2018
Editor: Ab Grootjans
_______________________________________________________________________________________
Author for correspondence:
Dr Sara Thornton, School of Geography, Geology and the Environment, University of Leicester, UK and
Borneo Nature Foundation, Jl. Bukit Raya No. 82, Palangka Raya 73112, Central Kalimantan, Indonesia.
Tel: +447518424922; E-mail: sat32@leicester.ac.uk or s.thornton.p@gmail.com
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
21
Appendix
Table A1. List of freshwater fish (Actinopterygii) species recorded in the Sebangau River and Forest together with IUCN
Red List classifications (DD = data deficient, LC = least concern, VU = vulnerable) and Borneo endemic species
assignments. None of these species are on the Indonesian protected species list. Data from Ng & Tan (2011) and Thornton
(2017). Additional local and Bahasa Indonesia species names are provided in Thornton (2017).
ORDER / Family
Genus
Species
English name
IUCN
Borneo
endemic?
BELONIFORMES
Zenarchopteridae
Hemirhamphodon
chrysopunctatus
tengah
CYPRINIFORMES
Cobitidae
Kottelatlimia
cf. pristes
Cyprinidae
Cyclocheilichthys
janthochir
Endemic
Desmopuntius
foerschi
Foersch's fire barb
Endemic
hexazona
Six-banded tiger barb
johorensis
Striped barb
rhomboocellatus
Snakeskin barb
Endemic
Eirmotus
sp. 1
Eight-banded barb
Osteochilus
melanopleura
Greater bony lipped barb
LC
spilurus
LC
Rasbora
cephalotaenia
Porthole rasbora
dorciocelatta
Eyespot rasbora
kalbarensis
Kalbar rasbora
Endemic
kalochroma
Clown rasbora
Striuntius
lineatus
Lined barb
Trigonopoma
gracile
Blackstripe rasbora
PERCIFORMES
Anabantidae
Anabas
testudineus
Climbing perch
DD
Channidae
Channa
bankanensis
Bangka snakehead
gachua
Forest snakehead
LC
melanoptera
Black finned snakehead
micropeltes
Giant snakehead
LC
pleurophthalmus
Oscellated snakehead
striata
Snakehead murrel
LC
Helostomatidae
Helostoma
temminckii
Kissing gourami
LC
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
22
ORDER / Family
Genus
Species
English name
IUCN
Borneo
endemic?
Nandidae
Nandus
nebulosus
Bornean leaffish
LC
Osphronemidae
Belontia
hasselti
Malay combtail
Betta
anabatoides
Giant betta
Endemic
foerschi
Endemic
hendra
Endemic
Luciocephalus
aura
Peppermint pikehead
pulcher
Giant pikehead
Sphaerichthys
acrostoma
Giant chocolate gourami
Endemic
osphromenoides
Chocolate gourami
Trichopodus
pectoralis
Snakeskin gourami
LC
Pristolepidae
Pristolepis
grootii
Indonesian leaffish
SILURIFORMES
Bagridae
Leiocassis
micropogon
Bumblebee catfish
sp.
Mystus
nigriceps
Twospot catfish
olyroides
Endemic
sp.
Chacidae
Chaca
bankanensis
Angler catfish
LC
Clariidae
Clarias
meladerma
Blackskin catfish
LC
nieuhofii
Slender walking catfish
LC
teijsmanni
Airbreathing catfish
Encheloclarias
tapeinopterus
VU
Schilbeidae
Pseudeutropius
moolenburghae
Sun catfish
Siluridae
Kryptopterus
sp.
Striped glass catfish
Ompok
leiacanthus
DD
Silurichthys
ligneolus
Brown leaf catfish
Endemic
phaiosoma
Hasselt's leaf catfish
Wallago
leeri
Striped wallago catfish
SYNBRANCHIFORMES
Mastacembelidae
Macrognathus
aculeatus
Lesser spiny eel
maculatus
Frecklefin eel
LC
Synbranchidae
Monopterus
albus
Asian swamp eel
LC
1 Potentially new species based on inspection in the field and of photographs. Requires specimen for confirmation.
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
23
Table A2. Abundances of each species for each month (Sep 2014 to Dec 2015) and habitat type (R = River, F = Forest). ‘x’ indicates that no survey was conducted.
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Nov
Dec
Genus
Species
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
Cyclocheilichthys
janthochir
9
0
43
0
39
0
5
0
0
0
1
0
5
0
2
0
1
0
5
0
0
0
0
0
3
0
14
0
13
0
Desmopuntius
foerschi
1241
0
0
0
12
0
274
0
29
0
133
0
271
0
340
0
146
0
113
0
2894
0
623
0
16
0
0
0
9
0
Desmopuntius
hexazona
0
x
0
x
0
x
1
x
0
x
1
0
3
2
0
2
0
0
0
0
156
0
7
x
0
x
0
x
0
x
Desmopuntius
johorensis
0
0
1
0
0
0
0
0
0
0
1
0
4
0
2
0
1
0
6
0
72
0
3
0
0
0
1
0
0
0
Desmopuntius
rhomboocellatus
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
83
0
0
0
0
0
0
0
0
0
Eirmotus
sp.
60
0
98
0
5
0
3
0
10
0
14
0
3
0
6
0
3
0
4
0
89
0
770
0
9
0
4
0
31
0
Osteochilus
melanopleura
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
Osteochilus
spilurus
1520
0
975
0
106
0
3839
0
189
0
573
0
1099
0
720
0
146
0
234
0
3155
0
4014
0
1021
0
64
0
211
0
Rasbora
cephalotaenia
508
x
11
x
36
x
114
x
49
x
117
1
352
6
569
4
558
1
239
1
1220
0
536
x
3
x
0
x
4
x
Rasbora
dorcioceletta
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Rasbora
kalochroma
0
x
0
x
0
x
0
x
0
x
0
315
0
422
0
306
0
545
0
320
0
45
0
x
0
x
0
x
0
x
Striuntius
lineatus
436
0
83
0
28
0
1
0
0
0
5
0
7
0
2
0
6
0
11
0
995
0
684
0
30
0
12
0
0
0
Trigonopoma
gracile
0
0
1
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Channa
bankanensis
0
x
0
x
0
x
1
x
0
x
0
9
0
12
0
10
0
31
0
40
0
9
0
x
0
x
0
x
0
x
Channa
gachua
0
x
0
x
1
x
0
x
0
x
0
21
0
26
0
29
1
33
0
61
1
4
1
x
0
x
0
x
0
x
Channa
melanoptera
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Channa
micropeltes
0
x
0
x
0
x
0
x
32
x
0
0
0
0
0
0
0
0
0
1
0
0
0
x
0
x
0
x
0
x
Channa
pleurophthalmus
0
0
1
0
0
0
0
0
0
0
0
0
0
0
2
0
1
0
1
0
2
0
3
0
1
0
0
0
0
0
Helostoma
temminckii
0
0
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
2
0
0
0
0
0
Nandus
nebulosus
335
x
101
x
257
x
22
x
1
x
3
3
5
0
21
0
19
0
56
3
840
1
642
x
77
x
24
x
16
x
Belontia
hasselti
6
x
7
x
4
x
0
x
6
x
0
54
5
31
7
10
15
8
23
6
57
0
17
x
59
x
0
x
0
x
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
24
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Nov
Dec
Genus
Species
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
R
F
Betta
anabatoides
0
x
0
x
0
x
0
x
0
x
0
20
0
39
0
54
0
99
0
137
0
52
0
x
0
x
0
x
0
x
Betta
foerschi
0
x
0
x
0
x
0
x
0
x
0
1
0
0
0
0
0
1
0
3
0
1
0
x
0
x
0
x
0
x
Luciocephalus
aura
0
0
0
0
4
0
1
0
0
0
0
0
1
0
3
0
0
0
2
0
3
0
71
0
82
0
0
0
0
0
Luciocephalus
pulcher
58
x
17
x
1
x
0
x
0
x
1
5
0
1
0
0
2
2
2
0
48
0
0
x
21
x
2
x
0
x
Sphaerichthys
acrostoma
458
0
190
0
4
0
0
0
0
0
0
0
5
0
0
0
0
0
7
0
8199
0
1939
0
212
0
0
0
0
0
Sphaerichthys
osphromenoides
0
x
1
x
0
x
0
x
0
x
0
0
0
1
0
1
2
0
15
0
0
0
0
x
93
x
0
x
0
x
Trichopodus
pectoralis
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Pristolepis
grootii
20
0
16
0
6
0
0
0
17
0
7
0
7
0
43
0
123
0
82
0
940
0
434
0
35
0
23
0
2
0
Leiocassis
micropogon
118
0
1
0
26
0
39
0
52
0
43
0
87
0
6
0
12
0
24
0
35
0
10
0
0
0
10
0
8
0
Leiocassis
sp.
0
x
0
x
0
x
0
x
0
x
0
0
0
1
0
0
0
0
0
0
0
0
0
x
0
x
0
x
0
x
Mystus
olyroides
890
x
235
x
371
x
154
x
52
x
39
0
49
3
110
0
90
2
138
0
1182
0
1579
x
80
x
48
x
17
x
Chaca
bankanensis
0
0
3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Clarias
meladerma/
teijsmanni
26
x
46
x
2
x
0
x
0
x
2
10
0
2
6
10
8
0
6
2
460
0
22
x
16
x
0
x
0
x
Clarias
nieuhofii
0
x
0
x
0
x
0
x
0
x
0
10
0
14
0
7
0
5
0
2
0
0
0
x
0
x
0
x
0
x
Encheloclarias
tapeinopterus
0
x
0
x
0
x
0
x
0
x
0
57
0
112
0
73
0
40
0
9
0
6
0
x
0
x
0
x
0
x
Pseudeutropius
moolenburghae
0
0
3
0
136
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
3
0
4
0
0
0
0
0
Kryptopterus
sp.
26
x
13
x
146
x
35
x
25
x
41
2
30
2
21
1
16
0
45
0
19
0
38
x
54
x
0
x
0
x
Ompok
leiacanthus
0
x
0
x
0
x
0
x
0
x
0
27
0
25
0
38
1
42
1
33
0
0
0
x
0
x
28
x
33
x
Silurichthys
phaiosoma
2
x
0
x
1
x
0
x
1
x
0
25
0
52
0
29
1
39
0
22
2
0
1
x
0
x
0
x
0
x
Macrognathus
aculeatus
0
x
0
x
0
x
0
x
0
x
0
0
0
0
0
0
0
0
0
0
3
0
0
x
0
x
0
x
0
x
Macrognathus
maculatus
3
x
4
x
12
x
0
x
0
x
0
1
0
2
1
1
0
1
0
0
16
0
6
x
3
x
1
x
0
x
Monopterus
albus
0
x
0
x
0
x
0
x
0
x
0
0
0
0
0
0
0
1
0
0
0
0
0
x
0
x
0
x
0
x
S.A. Thornton et al. PEATLAND FISH OF SEBANGAU: DIVERSITY, MONITORING, CONSERVATION
Mires and Peat, Volume 22 (2018), Article 04, 1–25, http://www.mires-and-peat.net/, ISSN 1819-754X
© 2018 International Mire Conservation Group and International Peatland Society, DOI: 10.19189/MaP.2017.OMB.313
25
Table A3. Statistical analysis (Spearman rho, rs or Pearson’s product correlation (PPC) if indicated) of the Sebangau River environmental variables: catch per unit
effort (CPUE), fish body size (SL) and species richness. These analyses are between monthly averages of each variable and exclude post-fire data; n = 13 except for
Secchi disk depth data analysis where n = 8 and correlation analysis was conducted with environmental variables for the corresponding months only (February
September 2015). * = p < 0.05, ** = p < 0.01, *** = p < 0.001.
CPUE
Body size
(SL)
Species
richness
Average
DO
Average
pH
Average depth
of river
Average Secchi
disk depth
Average
temperature
Average
rainfall
Average
P
Average
NO3
Average DO
-0.148
-0.181
-0.450
Average pH
-0.121
-0.071
-0.132
-0.154
Average depth of river
-0.571*
0.000
-0.455
0.714**
0.132
Average Secchi disk depth
-0.5
-0.024
-0.216
-0.19
0.238
0.119
Average temperature
0.049
-0.250
0.586* (PPC)
-0.324
0.253
-0.159
0.248 (PPC)
Average rainfall
-0.429
0.179
-0.478
0.718**
0.297
0.784**
0.108
-0.393
Average P
-0.126
0.654*
-0.359
0.044
0.121
0.214
-0.238
-0.269
0.523
Average NO3
0.184
-0.327
-0.169
0.757**
0.033
0.561*
-0.431
-0.432
0.656*
0.146
Average NO2
0.3
-0.447
0.403
0.147
-0.107
0.158
-0.024
0.362
-0.204
-0.48
0.192
... By 2015, only 6.4% of peat swamp forests in peninsular Malaysia, Sumatra and Borneo remained in a pristine condition (Miettinen et al., 2016), placing several obligate peat forest species under threat of extinction Thornton et al., 2018). In addition, the habitat quality of remaining areas of forested peatland is being reduced by habitat fragmentation, drainage impacts, fire from surrounding landscape and unsustainable (and often illegal) timber extraction (Miettinen et al., 2016). ...
... In their undisturbed intact state, tropical peatlands form a unique habitat in the SE Asian region because of their high water-tables and deep layers of organic matter (OM) which often separate plant root systems from underlying parent materials. Peat swamp forests support a high diversity of biota, some of which are endemic to this ecosystem Posa et al., 2011;Thornton et al., 2018). In pristine conditions, around 45 higher plant species (~3% of the peat swamp forest flora), mainly trees such as Dyera polyphylla, Palaquium cochleariifolium and Shorea spp., are restricted to SE Asian peatlands . ...
Article
About half of the world’s tropical peatlands occur in Southeast (SE) Asia, where they serve as a major carbon (C) sink. Nearly 80% of natural peatlands in this region have been deforested and drained, with the majority under plantations and agriculture. This conversion increases peat oxidation which contributes to rapid C loss to the atmosphere as greenhouse gas emissions and increases their vulnerability to fires which generate regional smoke haze that has severe impacts on human health. Attempts at restoring these systems to mitigate environmental problems have had limited success. We review the current understanding of intact and degraded peatlands in SE Asia to help develop a way forward in restoring these ecosystems. As such, we critically examine them in terms of their biodiversity, C storage, hydrology and nutrients, paying attention to both above‐ and below‐ground subsystems. We then propose an approach for better management and restoration of degraded peatlands that involves explicit consideration of multiple interacting ecological factors and the involvement of local communities who rely on converted peatlands for their livelihood. We make the case that as processes leading to peatland development involve modification of both above‐ and below‐ground subsystems, an integrated approach that explicitly recognizes both subsystems and their interactions is key to successful tropical peatland management and restoration. Synthesis and applications. Gaining a better understanding of not just carbon stores and their changes during peat degradation, but also an in‐depth understanding of the biota, nutrient dynamics, hydrology and biotic and abiotic feedbacks, is key to developing better solutions for the management and restoration of peatlands in Southeast Asia. Through the application of science‐and nature‐based solutions that recognize the interactions among the above‐ and below‐ground subsystems, and taking into account the livelihood needs of local people, we propose a way to mitigate the ongoing environmental damage that is occurring in these iconic and unique ecosystems.
... Previous studies in tropical peatlands have described negative impacts of fire on floral and faunal biodiversity (e.g., Yeager et al., 2003;Thornton et al., 2018;Harrison et al., 2021). Our observation of fire presence within the PSWR during both wet and mostly dry years therefore indicates that the reserve's biodiversity is under serious threat through fire-induced habitat destruction and isolation within their boundaries. ...
Article
Full-text available
Fire is considered a major threat to biodiversity in many habitats and the occurrence of fire has frequently been used to investigate the effectiveness of protected areas. Yet, despite the known importance of tropical peatlands for biodiversity conservation and serious threat that anthropogenically induced fires pose to this ecosystem, the influence of protected area designation on fire occurrence in tropical peatland has been poorly assessed thus far. Our study addresses this knowledge gap through providing a novel assessment of fire patterns from a tropical peatland protected area and surrounding landscape. We investigated the importance of both climatic factors (top-down mechanism) and human interventions (bottom-up mechanism) on fire occurrence through analyzing 20-years (2001–2020) of LANDSAT and Moderate Resolution Imaging Spectrometer (MODIS) images of the Padang Sugihan Wildlife Reserve and a 10-km buffer area surrounding this in Sumatra, Indonesia. Fire density was assessed in relation to road and canal construction. Monthly and annual precipitation was compared between wet and dry years. The reserve was effective in limiting fire compared to surrounding landscapes only in wet years. We revealed that peat fire occurrence in the protected area and buffer zone was not due to climatic factors alone, with distance from canals and roads also contributing toward fire occurrence. Our results suggest that it is essential to address tropical peatland fire processes at a landscape level, particularly at the surroundings of protected areas, in order to increase the effectiveness of fire protection, improve fire risk classification maps, and conserve threatened tropical peatland wildlife such as the Sumatran elephant.
... Lowland tropical peatlands are generally covered in dense swamp forest, providing habitats for a diversity of plants and animals, many of which are adapted to the low-nutrient, waterlogged conditions Posa et al., 2011). They also provide a range of tangible and intangible services to people: fishing grounds (Thornton et al., 2018), water for agriculture and human consumption throughout drier seasons, a range of timber and non-timber forest products (NTFPs) (Posa et al., 2011), and as spaces of cultural significance for local communities (e.g., Schulz et al., 2019a;Thornton et al., 2020). ...
Article
The status of tropical peatlands, one of Earth’s most efficient natural carbon stores, is of increasing international concern as they experience rising threat from deforestation and drainage. Peatlands form over thousands of years, where waterlogged conditions result in accumulation of organic matter. Vast areas of Southeast Asian peatlands have been impacted by land use change and fires, whilst lowland tropical peatlands of Central Africa and South America remain largely hydrologically intact. To predict accurately how these peatlands may respond to potential future disturbances, an understanding of their long-term history is necessary. This paper reviews the palaeoecological literature on tropical peatlands of Southeast Asia, Central Africa and South America. It addresses the following questions: (i) what were the past ecological dynamics of peatlands before human activity?; (ii) how did they respond to anthropogenic and natural disturbances through the palaeoanthropocene, the period from whence evidence for human presence first appeared?; and, (iii) given their past ecological resilience and current exposure to accelerating human impacts, how might the peatlands respond to drivers of change prevalent in the anthropocene? Throughy synthesising palaeoecological records, this review demonstrates how tropical peatland ecosystems have responded dynamically, persisting through fire (both natural and anthropogenic), climatic and human-induced disturbances in the palaeoanthropocene. Ecosystem resilience does, however, appear to be compromised in the past c. 200 years in Southeast Asian peatlands, faced with transformative anthropogenic impacts. In combination, this review’s findings present a pantropical perspective on peatland ecosystem dynamics, providing useful insights for informing conservation and more responsible management.
... The unique habitat often harbors a distinct set of species (Posa et al., 2011), novel species assemblages or provides unique resources that are otherwise unavailable or rare outside of peat swamp habitat (Householder et al., 2010;Tobler et al., 2010). In addition, populations of species that encounter or inhabit peat swamps may undergo behavioral, morphological, or physiological change in response to the unique ecological setting, which itself underpins trait evolution and species diversification (Thornton et al., 2018). Far from anomalous exceptions to high tropical biodiversity, peat swamps provide a marked example of the importance of environmental heterogeneity in its maintenance and generation. ...
Chapter
Aim - Peat swamps are a unique class of tropical forest characterized by their deep organic soils, which accrue from slowly decomposing plant debris. Main Concepts Covered - We overview the environmental conditions that permit the development of peat swamp forests, from local processes that allow peat to accumulate, to the regional processes that determine their global distribution. We then turn to assess the relevance of peat swamps to biodiversity and the myriad ways in which local floras and faunas inhabit and interact with them. Outlook - While peat swamps have functioned as carbon sinks over millennia, ongoing degradation will continue to convert many into globally significant carbon sources.
... (Posa et al., 2011). Sejak 1993 telah direkam lebih dari 1100 spesies potensial di hutan Sebangau, yang terdiri atas 215 spesies kayu, 92 spesies tanaman non-kayu, 72 spesies semut, 66 spesies kupu-kupu, 297 spesies laba-laba, 41 spesies capung, 55 spesies ikan, 11 spesies amfibi, 46 spesies reptil, 172 spesies burung, dan 65 spesies mamalia (Thornton et al., 2018). Dari semua daftar spesies ini, 46 spesies terancam secara global, dan 59 spesies sudah dilindungi di Indonesia (Husson, 2018). ...
... The wetland forests of the coast of Southeast Asia have developed over thousands of years (Dommain et al., 2011), and provide multiple ecosystem services to people both locally and across the world (Page et al., 2011;Phillips, 1998;Posa et al., 2011;Silvius and Giesen, 1996). The international body of research documenting the functioning of this ecosystem is increasing in response to the size of the threat to it (e.g., Silvius and Giesen, 1996;Phillips, 1998;Yule, 2010;Posa et al., 2011;Prenctice, 2011;Cook et al., 2018;Thornton et al., 2018;Wijedasa et al., 2018). Recent international attention has focused on the role of tropical peatlands as a sink and store of fossil carbon, vital in regulating our climate (Jaenicke et al., 2008;Miettinen et al., 2017) and thus a potential nature-based solution for mitigating ongoing climatic change . ...
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The effective conservation and sustainable management of tropical peatlands in Southeast Asia is a major challenge. Pervasive deforestation, drainage and conversion to agricultural land, is disrupting the ecosystems’ ability to sequester atmospheric carbon. Conserving peatlands in an intact state has been described as a “low hanging fruit in tackling climate change” by the international conservation community. Yet, peatland drainage and land conversion continue unabated. Focusing on Malaysia’s coastal peatlands, this study interrogates local and global perspectives on peatland conversion. We combine diverse datasets obtained using palaeoecological and social science research methods to provide a comprehensive context to this conservation challenge. We also identify where the local and global perspectives are in conflict and where they align. To do this, we employ a literature review and qualitative analysis of the interview data, enabling us to draw out key themes of local versus global discourses on the current management and future prospects of these peatland ecosystems. Palaeoecological data, derived from cores collected from three peatlands in Sarawak, Malaysian Borneo, provide a quantitative assessment of long-term ecological changes in these environments; qualitative surveys of local stakeholders provide complementary detail on the history of and future perspectives on human-peatland interaction. Finally, a comparison of interview data with key themes in the international discourses on peatland conservation, illustrates conflicts between the two. The coastal peatlands of Sarawak serve as a case study to explore the fragile context of sustainable tropical peatland management, illustrating the diversity of datasets and knowledges that can be integrated. This approach enables a more effective dialogue amongst the multiple stakeholders involved in the management of these globally important ecosystems.
... After rewetting, revegetation can be done with the paludiculture concept using native species and species adaptive to acidic soils 51 (Hansson and Dargusch 2018). For (severely degraded) peatland near village areas, choosing a combination of species such as in agroforestry and fishery practices can help ensure the community still gains economic benefits from this revegetation (Giesen 2015;Giesen and Sari 2018;Thornton et al. 2018). 52 Conducting revegetation after rewetting activities will help the process of peat formation, thus potentially restoring the tropical peat ecosystem (Jauhiainen et al. 2008a). ...
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This study assessed critical aspects in the governance of peatland restoration in South Sumatra and its possible impacts.
... Fire use in peatlands has also been attributed to local livelihood activities, such as using it to clear vegetation to create inland fish ponds and stimulate nutrient accumulation for fish (Chokkalingam et al., 2005;Thornton et al., 2018) and for forest-based hunting activities (Tacconi & Vayda, 2006). Within the social sciences, however, recent studies have advanced understanding of the complex social, political, and economic dynamics underpinning peat fire occurrence in Indonesia. ...
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Near‐annual landscape‐scale fires in Indonesia's peatlands have caused severe air pollution, economic losses, and health impacts for millions of Southeast Asia residents. While the extent of fires across the peatland surface has been widely attributed to widespread peatland drainage for plantation agriculture, fires that transition from surface into sub‐surface soil‐based fires are the source of the most dangerous air pollution. Yet the mechanisms by which this transition occurs have rarely been considered, particularly in diversely managed landscapes. Integrating physical geography methods, including active fire scene evaluations and hydrological monitoring, with qualitative methods such as retrospective fire scene evaluations and semi‐structured interviews, this article discusses how and why sub‐surface peat fire transition occurs in an intensively altered peatland ecosystem in Indonesia's Central Kalimantan province. We demonstrate that variable water table levels and flammable surface vegetation (fire fuels) are co‐produced socio‐political and biophysical phenomena that enable the conditions in which surface fire is likely to transition into peat fire and increase landscape vulnerability to ongoing, uncontrollable annual fires. This localized understanding of peat fire transition counters normative causal narratives of tropical fire such as ‘slash‐and‐burn’, with implications for the management of new fire regimes in inhabited landscapes.
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Tropical peatlands have attracted a great deal of attention due to their vast area in the tropics and their massive carbon and water stocks. At the same time, improper management of peatlands (i.e., drainage of peatlands, often resulting in large fires, carbon dioxide emissions that have a significant impact on global climate change, and health hazards due to smoke pollution) has been a major concern.
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