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TRANSCRIPT
Sikundur Monitoring Post
Annual Report for 2014
2015
SUMATRAN ORANGUTAN CONSERVATION PROGRAMME
1
Contents I. Introduction .......................................................................................................................................... 1
II. Climatological & Phenological Monitoring .................................................................................. 4
III. Habitat Monitoring ............................................................................................................................ 6
IV. Orangutan Project .......................................................................................................................... 10
V. Camera Trapping ............................................................................................................................. 16
VI. Unmanned Aerial Vehicle (UAV) Technology .......................................................................... 19
VII. Student Projects ............................................................................................................................ 22
-Habitat Structure ............................................................................................................................... 23
-Orangutan/Primate Vocalizations ................................................................................................... 23
-Gibbon, Siamang, and Leaf Monkey Surveys ............................................................................... 25
-Orangutan Nest Surveys.................................................................................................................. 26
VIII. Coming Up In 2015-2016 ............................................................................................................ 27
IX. References Cited ............................................................................................................................ 29
X. How to Get Involved ....................................................................................................................... 32
2
I. Introduction
Throughout their range, Sumatran orangutans are threatened by two often related
factors, habitat loss and poaching/hunting. Deforestation in Sumatra, a product of
ongoing human extractive industries (e.g., development of infrastructure, expansion of
large-scale agriculture, logging concessions, mining, and small-scale localized
encroachment), is primarily attributed to inadequate cross-sectorial land use planning,
desire for short-term economic growth, and a lack of environmental law enforcement
(Wich et al. 2011a). Most worrisome is that Sumatra’s lowland and swamp forests,
areas known to house the highest densities of orangutans (Wich et al. 2008), also have
the highest rates of deforestation (Laumonier et al. 2010; Margono et al. 2012). While
more difficult to quantify (i.e., relative to forest loss), poaching/hunting is an additional
threat to the survival of Sumatran orangutans, and is largely associated with access to
forested areas, a byproduct of deforestation/habitat fragmentation and population
growth (Wich et al. 2011a).
Interestingly, virtually all long-term monitoring studies of Sumatran orangutans, and
indeed all data in recent population viability analyses of the species (Marshall et al.
2009), have utilized ‘high-density’ orangutan populations situated in primary peat-
swamp forest (Suaq Balimbing, Aceh Province) and primary lowland rainforest
(Ketambe, Aceh Province). These two sites are regarded as “prime habitats” for
Sumatran orangutans (Husson et al. 2009) and historically have suffered relatively
lower levels of human disturbance. Accordingly, we lack knowledge of Sumatran
orangutans in more degraded landscapes, and thus also lack a complete grasp of their
behavioral, demographic, ecological, and physiological variability, factors vital to
understanding their future population viability (Marshall et al. 2009).
The Sikundur Monitoring Post is located in the Langkat District of North Sumatra
Province, within the Gunung Leuser National Park and larger Leuser Ecosystem
National Strategic Area [Fig. 1]. It consists of previously logged lowland dipterocarp
tropical rainforest, and even so, is one of the few remaining lowland areas that still
maintains suitable forest habitat for the Critically Endangered Sumatran orangutan. As
such, the importance of the Sikundur Monitoring Post and its relevance to long-term
Sumatran orangutan conservation must be underscored. The Sumatran Orangutan
Conservation Programme (SOCP) started orangutan and habitat monitoring at Sikundur
in the second half of 2012 and is now in its third year of operation there.
Building off of 2013’s successes, the 2014 field season at Sikundur was full of a lot of
new developments and a tremendous amount of progress. These include an increase in
orangutan follows and some new focal individuals, additions to the long-term
3
climatological and phenological datasets, more intensified habitat monitoring efforts,
camera trapping, comparative drone nest surveys, and three new student projects. The
purpose of this short report will be to highlight some of these activities and emphasize
Sikundur’s importance to orangutan conservation and also the conservation of
Sumatra’s unique biodiversity.
Fig. 1. The location of the Sikundur Monitoring Post in relation to the Gunung
Leuser National Park and the Leuser Ecosystem National Strategic Area.
4
II. Climatological & Phenological Monitoring
At the Sikundur Monitoring Post, the average monthly rainfall during August 2013 –
February 2015 was 256.4 mm, with a monthly range of 12.4-535.4 mm [Fig. 2]. During
2014, the only complete year of observation, the total amount of rainfall was 3,042.8
mm. In general, higher levels of rainfall occurred during April-May, September-October,
and December, whereas low levels of rainfall occurred during January-March, June-
July, and November. Both February and March of 2013 were found to be below 100
mm, indicating extreme lows in rainfall.
Fig. 2. The average rainfall and temperature for the Sikundur Monitoring Post from August
2013 – February 2015.
Average monthly temperatures from within the field station were 27.3° C, with a monthly
range of 26.1-29.2° C [Fig. 2]. During the observation period, temperature highs were
recorded for the months February-July, whereas temperature lows were recorded for
the months of October-January.
5
Fig. 3. The average rainfall and percent fruit productivity for the Sikundur Monitoring Post
from June 2013 – February 2015.
The average percent of lianas and trees (>10 cm diameter at breast height) that were
bearing fruit in our 20 phenological plots was 3.6% for the period of June 2013 –
February 2015, with a range of 0.3-13.0% [Fig. 3]. High fruiting values were observed
during May and July-September, with low fruiting values being observed during
December-April. Extreme high fruiting values were observed for June-October 2014.
We are hesitant to suggest that a masting event occurred during this period, given that
the phenology dataset included in this study encompasses only 21 months; however,
the range of fruiting values indicates that there is a considerable level of fruiting
variability at the Sikundur study site.
It is interesting to note that the average fruiting score for Sikundur (3.6%) falls within the
percent fruiting score range of a number of Bornean field sites (3.0-6.8%); however
conversely, it is well outside the range of percent fruiting scores of two Sumatran (6.9-
30.57%) sites, Ketambe and Suaq Balimbing (Wich et al. 2011b). Thus, the Sikundur
Monitoring Post has lower fruit productivity than that of previously studied Sumatran
orangutan field sites, indicating that Sumatra is far less homogeneous than currently
thought and that a portion of remaining orangutan habitat in Sumatra is far less
productive than previously thought.
6
III. Habitat Monitoring
The Sikundur area, previously the Sikundur Reserve (est. 1938) prior to the formation of
the Gunung Leuser National Park (est. 1980) was selectively logged starting in the late
1960’s, which continued and progressively intensified in some areas until the 1980’s
(Cribb, 1988; Wind, 1996). Following the establishment of the Gunung Leuser National
Park, logging in the Sikundur area continued primarily at the park boarder. Currently,
illegal logging and in some cases complete land clearing are still present near the
southeastern boundary of the Sikundur Monitoring Post at the Gunung Leuser National
Park border, in addition to more generalized illegal human extractive activities (e.g., bird
trapping, damar resin extraction, and fishing), which will be discussed in more detail
below. Our analysis of forest disturbance/loss in the Langkat District from 2013-2014,
using monthly FORMA forest loss data downloaded freely from the Global Forest Watch
website (www.globalforestwatch.org; Hammer et al. 2013; Hansen et al. 2013),
discovered 409 forest disturbance ‘hotspots’ (resolution 500m x 500m) in the Langkat
District during this period [Fig. 4]. A total of 94 of these 409 ‘hotspots’ (23% of all
‘hotspots’ within the Langkat District) are within 10 kilometers of the Sikundur Monitoring
Post and also within the Leuser Ecosystem National Strategic Area. These disturbance
‘hotspots’ have allowed us to focus our habitat monitoring efforts on key areas of
deforestation within the Gunung Leuser National Park and the Leuser Ecosystem
National Strategic Area and provide a starting point for more detailed monitoring.
For example, last year in May of 2014, using unmanned aerial vehicles (UAVs), we
surveyed a large area of deforestation <1.5 kilometers from SOCP’s camp within the
Sikundur Monitoring Post. This aerial survey allowed for the production of a highly
detailed photomosaic showing the level of deforestation [Fig. 5]. A subsequent field
report was successful in prompting a patrol team from the Gunung Leuser National Park
to come and remove the illegal encroachers. Unfortunately, the illegal encroachers have
again entered the research station during the end of 2014 and beginning of 2015 and
have again started land clearing within the Gunung Leuser National Park [Fig. 6]. The
proper authorities have already been notified; however, a patrol team has not yet come
to take action. This unfortunate situation serves to highlight that early detection and
immediate responses from the proper authorities can be implemented to reduce illegal
activities, but that adequate follow-up activities are required to maintain any of these
positive achievements. Our observations also indicate that the threat of deforestation to
orangutans is ongoing and that in some cases, protected areas will likely not be enough
to preserve orangutan habitat, if the proper authorities are unable to adequately enforce
current laws.
7
Fig. 4. Forest loss in the Langkat District. The spatial data was collected from the
Global Forest Watch website (www.globalforestwatch.org; Hammer et al. 2013;
Hansen et al. 2013). The black dashed circle highlights the area nearest the
Sikundur Monitoring Post. Note the blue and green squares within the circle,
which are FORMA deforestation alerts from 2013 and 2014.
8
Fig. 5. Recent forest loss in the Sikundur Monitoring Post. A) Forest
loss in relation the Sikundur Monitoring Post. The spatial data was
collected from the Global Forest Watch website
(www.globalforestwatch.org; Hammer et al. 2013; Hansen et al.
2013). B) UAV photographs showing cleared land from May 2014.
A.
B.
9
Fig. 6. Photographs showing illegal encroachment within both the Gunung Leuser
National Park and the Leuser Ecosystem National Strategic Area from 2014. Note that
the area is also within the grid of the Sikundur Monitoring Post. Photographs by James
Askew.
10
IV. Orangutan Project
The 2014 field season was tremendously successful and follows increased from 111
follow days in 2013 to 359 follow days in 2014 [Table 1]. In addition, there were three
new adult orangutans (one female and two males) that were contacted and followed in
2014, plus one of the resident females (Madeline) gave birth in June of 2014. This has
brought our total of habituated animals to 15, including 5 adult females, 6 adult males,
and 4 infants.
Results from all orangutan follows >3 hours duration suggest that on average (n=21
months), adult orangutans at Sikundur were found to feed 48.5% of the time [Fig. 7],
followed by rest ( x =31.1%), travel ( x =18.3%), and other ( x =2.2%). During periods of
fruit scarcity (n=10 months), adult orangutans were observed to feed 55.1% of the time,
followed by rest ( x =26.0%), travel ( x =17.0%), and other ( x =1.9%). Conversely
during periods of fruit abundance (n=8 months), adult orangutans were observed to feed
40.9% of the time, followed by rest ( x =35.8%), travel ( x =19.8%), and other ( x
=2.9%). Thus, the primary differences were more feeding during fruit scarce periods,
with greater emphasis on all other behaviors during fruit abundant periods.
During the observation period, adult orangutans were observed to feed primarily on fruit
( x =62.0%), followed by leaves ( x =14.9%), bark ( x =9.7%), piths/stems ( x =5.4%),
invertebrates ( x =4.8%), flowers ( x =2.7%), and other ( x =0.6%) [Fig. 8]. When fruit
was scarce, adult orangutans were observed to feed on fruit ( x =47.2%), leaves ( x
=18.2%), bark ( x =16.7%), piths/stems ( x =7.6%), invertebrates ( x =5.9%), flowers ( x
=4.1%), and other ( x =0.3%). When fruit was abundant, adult orangutans were
observed to feed on fruit ( x =81.4%), leaves ( x =7.4%), piths/stems ( x =4.2%),
invertebrates ( x =3.4%), bark ( x =1.8%), flowers ( x =0.9%), and other ( x =0.9%). The
primary differences are the significant amount of fruit feeding during fruit abundant
periods and the significant amount of feeding on lower quality food resources (e.g., bark
and leaves) during fruit scarce periods.
These differences in activity budgets are likely related a greater handling time needed
with lower quality resources in the fruit scarce months and the emphasis on travelling to
higher quality resources during fruit abundant months, plus the energetic freedom to
utilize time for rest and social behaviors. These results are quite different from that of
previously published Sumatran orangutan populations and indicate that orangutans in
Sikundur are impacted seasonally by fruit availability. These results also suggest that
Sikundur orangutans utilize a feeding/foraging strategy that is intermediate between
Bornean and Sumatran orangutans, making the division between Bornean and
11
Sumatran orangutans more enigmatic (Morrogh-Bernard et al. 2009). Given that this is
the first study to conduct orangutan research on the eastern portion of the Bukit Barisan
Mountain Range, a known climatological barrier, these results have important
conservation implications for the remaining orangutan population in the eastern portion
of the Leuser Ecosystem National Strategic Area. This, in combination with our
analyses of fruiting seasonality, highlights that we are just starting to understand
Sumatran orangutan population variability and that these and future results will be vital
to our current and future viability analyses and conservation strategies.
12
Nam
eA
ge C
lass
Sex
Jan
Feb
Mar
Ap
rM
ayJu
nJu
lA
ug
Sep
Oct
No
vD
ec
An
toA
du
ltM
ale
--
--
--
--
--
--
Be
nd
ot
Ad
ult
Mal
e-
--
--
1-
--
--
-
Irm
a +
off
spri
ng
Ad
ult
Fem
ale
--
--
--
--
-5
--
Irva
n (
Irm
a’s
off
spri
ng)
Infa
nt
Mal
e-
--
--
--
--
5-
-
Jam
es
Ad
ult
Mal
e-
--
--
--
--
--
-
Ku
nd
ur
(Be
nd
ot
Ke
cil)
Ad
ult
Mal
e2
--
--
--
--
--
-
Mad
eli
ne
Ad
ult
Fem
ale
--
10-
4-
5-
--
53
Mat
Pan
gko
rA
du
ltM
ale
--
--
--
5-
--
--
Om
pu
ng
Ad
ult
Mal
e-
-5
1-
2-
--
--
-
Rak
el
Ad
ult
Fem
ale
--
--
--
--
--
--
Sib
oy
- (S
uci
's o
ffsp
rin
g)In
fan
t?
--
64
5-
5-
--
--
Suci
+ o
ffsp
rin
gA
du
ltFe
mal
e-
-6
45
-5
--
--
-
Yan
ti +
off
spri
ng
Ad
ult
Fem
ale
--
-1
6-
--
2-
--
Yen
i (Ya
nti
's o
ffsp
rin
g)In
fan
t?
--
-1
6-
--
2-
--
Tota
l-
-2
027
1126
320
04
105
3
Nam
eA
ge C
lass
Sex
Jan
Feb
Mar
Ap
rM
ayJu
nJu
lA
ug
Sep
Oct
No
vD
ec
An
toA
du
ltM
ale
--
--
-3
--
2-
--
Be
nd
ot
Ad
ult
Mal
e4
1-
-10
--
--
--
-
Irm
a +
off
spri
ng
Ad
ult
Fem
ale
108
-8
22
2-
5-
--
Irva
n (
Irm
a’s
off
spri
ng)
Infa
nt
Mal
e10
8-
72
2-
-5
--
-
Jam
es
Ad
ult
Mal
e-
--
--
31
--
--
-
Ku
nd
ur
(Be
nd
ot
Ke
cil)
Ad
ult
Mal
e-
--
--
74
3-
--
-
Mad
eli
ne
+ o
ffsp
rin
gA
du
ltFe
mal
e-
61
111
9-
2-
75
5
Mal
ala
(Mad
eli
ne
's o
ffsp
rin
g)In
fan
t?
--
--
-9
--
-6
55
Mat
Pan
gko
rA
du
ltM
ale
--
--
--
--
--
--
Om
pu
ng
Ad
ult
Mal
e-
-10
5-
-4
-1
810
2
Rak
el
Ad
ult
Fem
ale
--
--
--
--
--
6-
Sib
oy
- (S
uci
's o
ffsp
rin
g)In
fan
t?
69
55
47
95
31
2-
Suci
+ o
ffsp
rin
gA
du
ltFe
mal
e6
95
54
79
53
12
-
Yan
ti +
off
spri
ng
Ad
ult
Fem
ale
23
-3
-1
--
1-
--
Yen
i (Ya
nti
's o
ffsp
rin
g)In
fan
t?
23
-3
-1
--
1-
--
Tota
l-
-40
4721
4723
5129
1521
2330
12
20
14
20
13
Tab
le 1
. Fo
cal o
ran
guta
ns
at S
iku
nd
ur
and
th
eir
20
13
-20
14
mo
nth
ly f
oll
ow
sch
ed
ule
s.
13
Fig. 7. Activity budgets of adult orangutans at the Sikundur Monitoring Post, comparing
between two seasonal periods.
Fig. 8. Diet of adult orangutans at the Sikundur Monitoring Post, comparing between two
seasonal periods.
14
Fig. 9. Photographs of two adult female orangutans at Sikundur. A) Madeline with Malala
her new infant and Anto (adult male) sitting nearby; B) Irma watching her infant Irfan play.
Photographs courtesy of James Askew.
A)
B)
15
Fig. 10. Photographs of two adult male orangutans at Sikundur. A) Ompung feeding on
termites; B Bendot Besar feeding on fruits. Photographs courtesy of James Askew.
A)
B)
16
V. Camera Trapping
Via a small crowd funding grant which was received through experiment.com, SOCP’s
Biodiversity Monitoring Unit, along with two graduate student researchers James Askew
(University of Southern California) and John Abernethy (Liverpool John Moores
University) developed a site wide camera trap survey of the Sikundur Monitoring Post.
Using a randomized grid of 30 camera traps, the survey sought to analyze the
distribution of animal species across the three main habitat types (i.e., alluvial, hill, and
plain forest) at the Sikundur Monitoring Post. The results from 2,700 camera traps
nights has yielded a list of at least 31 animal species from 19 families, and three classes
[Table 2]. From this list, eight are identified as Vulnerable (VU) by the IUCN, with three
being identified as Critically Endangered (CR). The Critically Endangered species
include the Sumatran elephant, orangutan, and tiger [Fig. 11-13].
The presence of orangutans on the camera traps is quite interesting, as Sumatran
orangutans do not commonly come to the ground, being characterized as almost strictly
arboreal (van Schaik et al. 2009). Nevertheless, in addition to the camera trap photos,
we have also documented ground use by a number of adult orangutans (both female
and male) during full day follows, some of which have foraged on the ground for a
couple of hours. These observations are being looked at in greater detail, as this is a
trait more common in some Bornean orangutan populations and thought to be at least
partially related to the lack of tigers in Borneo (van Schaik et al. 2009; Ancrenaz et al.
2014).
Unfortunately, one of the most photographed species was humans. From the
photographs, it was clear that their primary activities in the forest include bird trapping,
damar resin extraction, fishing, and illegal logging. This also highlights the potential
importance of camera traps in habitat protection.
17
Class Family Species Common Name IUCN Status
Aves Bucerotidae Berenicornis cornatus White-crowned hornbill NT
Aves Bucerotidae - - -
Mammalia Cercopithecidae Macaca fascicularis Long-tailed Macaque LC
Mammalia Cercopithecidae Macaca nemestrina Pig-tailed Macaque VU
Mammalia Cercopithecidae Presbytis thomasi Thomas's Leaf Monkey VU
Mammalia Cercopithecidae - - -
Mammalia Cervidae Muntiacus muntjac Red Muntjac DD
Mammalia Cervidae Rusa (Cervus) unicolor Sambar Deer VU
Mammalia Cervidae - - -
Aves Columbidae Chalcophaps indica Emerald Dove LC
Aves Columbidae - - -
Mammalia Elephantidae Elephas maximus sumatranus Asian Elephant CR
Mammalia Elephantidae - - -
Mammalia Erinaceidae Echinosorex gymnurus Moonrat DD
Mammalia Erinaceidae - - -
Mammalia Felidae Catopuma temminck ii Asiatic Golden Cat NT
Mammalia Felidae Neofelis diardi Sunda Clouded Leopard VU
Mammalia Felidae Pardofelis marmorata Marbled Cat VU
Mammalia Felidae Felis bengalensis Leopard Cat DD
Mammalia Felidae Panthera tigris sumatrae Sumatran Tiger CR
Mammalia Felidae - - -
Mammalia Herpestidae Herpestes brachyurus Short-tailed Mongoose LC
Mammalia Herpestidae - - -
Mammalia Hominidae Homo sapiens Human LC
Mammalia Hominidae - - -
Mammalia Hystricidae Hystrix sumatrae Sumatran Porcupine LC
Mammalia Hystricidae - - -
Mammalia Mustelidae Martes flavigula Yellow-Throated Martin LC
Mammalia Mustelidae - - -
Aves Phasianidae Rollulus rouloul Crested Partridge NT
Aves Phasianidae - - -
Mammalia Pongidae Pongo abelii Sumatran Orangutan CR
Mammalia Pongidae - - -
Reptilia Pythonidae Python reticulatus Reticulated Python NE
Reptilia Pythonidae - - -
Mammalia Sciuridae Ratufa bicolor Black Giant Squirrel NT
Mammalia Sciuridae Sundasciurus hippurus Horse-tailed Squirrel NT
Mammalia Sciuridae - - -
Mammalia Suidae Sus scrofa Wild Boar LC
Mammalia Suidae - - -
Mammalia Tragulidae Tragulus javanicus Lesser Mouse Deer DD
Mammalia Tragulidae Tragulus napu Greater Oriental Chevrotain LC
Mammalia Tragulidae - - -
Mammalia Ursidae Helarctos malayanus Sun Bear VU
Mammalia Ursidae - - -
Mammalia Viverridae Arctictis binturong Binturong VU
Mammalia Viverridae Arctogalidia trivirgata Small-toothed Palm Civet LC
Mammalia Viverridae Hemigalus derbyanus Banded Civet VU
Mammalia Viverridae Paradoxurus hermaphroditus Common Palm Civet LC
Mammalia Viverridae - - -
Total 19 31 - -
Table 2. Animal Species Detected on Camera Traps in the Sikundur Monitoring Post
18
Fig. 11. The Critically Endangered Sumatran elephant from a camera trap photo. Photo by SOCP.
Fig. 12. The Critically Endangered Sumatran orangutan (Ompung) from a camera trap photo. Photo by
Sonny Royal/SOCP.
19
Fig. 13. The Critically Endangered Sumatran tiger from a camera trap photo. Photo by SOCP.
VI. Unmanned Aerial Vehicle (UAV) Technology
In December – January of 2014, SOCP’s UAV team worked alongside SOCP’s
Sikundur team to undertake a unique orangutan nest survey, which attempts to
compare two survey methods, aerial UAV nest surveys and ground-based nest surveys
[Fig. 14-15]. The monitoring project, which is jointly undertaken by both SOCP and
Conservation Drones seeks to develop the UAV survey methodology, so that orangutan
nest surveys can be conducted more efficiently and over larger landscapes than is
currently possible for ground-based surveys. Fig. 14 shows an example plot mosaic that
is 1000 x 50 meters. In theory, an algorithm would be utilized to detect orangutan nests
(e.g., the nests from a UAV photo shown in Fig. 14) within a given transect mosaic and
then orangutan densities would be calculated from these figures and a correction factor
for non-detected nests. The results are currently being analyzed.
During the same period as the UAV nest survey, SOCP was also able to create a
detailed mosaic of the entire Sikundur station (ca. 8 km2) and this will serve as the basis
for a number of future analyses, including forest structure and orangutan travel paths
[Fig. 15-16]. We also note that when compared with Fig. 5, the areas that were cleared
in May 2014 were already beginning to grow back, highlighting the capability of UAV
technology in detecting and monitoring critical forest habitats.
20
1000 meters
50 meters
Fig. 14. An example of the aerial nest survey
undertaken by SOCP at the Sikundur Monitoring Post
at the end of 2014 (left). Ten transects, each 1000 x
50 meters, were surveyed by both the UAV’s and
SOCP staff. Comparisons will be made to see if it is
possible to utilize UAV’s to do orangutan surveys,
something that would be highly cost effective and
would allow for greater aerial coverage. The
photograph to the top is an example of two
orangutan nests that were detected using UAV’s.
Both images are from Conservation Drones
(conservationdrones.org), via Dr. Serge Wich and Dr.
Lian Pin Koh.
Nest
21
Fig. 15. Photographs showing SOCP’s Sikundur team (top) and a member of
SOCP’s UAV team (bottom) conducting the ground-based and aerial surveys,
respectively.
22
Fig. 16. A photomosaic of the entire Sikundur Monitoring Post which was created by SOCP using
multiple UAV flights at the end of 2014 and beginning of 2015. Note that a few of the areas that had
been encroached upon (outlined in red) in May 2014 have already started to grow back. See Fig, 5 for
comparison. The yellow lines are the station’s grid system and the purple line is the border of the
Gunung Leuser National Park. The photomosaic is courtesy of Graham Usher, SOCP’s UAV
specialist.
VII. Student Projects
SOCP has been lucky enough to establish collaborations with the Bournemouth
University (UK), Liverpool John Moores University (UK), and University of Southern
California (USA). These new collaborations have already allowed for the development
of some very interesting projects, which are currently being undertaken by graduate
student from the aforementioned universities. The focus for 2014-2015 has been a
detailed look at habitat structure, primate surveys, and primate vocalizations.
23
-Habitat Structure
Two Master’s students from Bournemouth University (Helen Slater & Rosanna
Consiglio) and one PhD student from Liverpool John Moores University (John
Abernethy), guided by Drs. Amanda Korstjens, Ross Hill, and Serge Wich have now
started to undertake a detailed look at habitat structure in the Sikundur Monitoring Post.
For this particular project, 10 transects from each of three main micro-habitat types
(alluvial, plain, and hill forest) were surveyed by the three graduate students [Fig. 17].
During the surveys, the students collected various habitat structural data, which will
eventually be linked to primate densities, primate behavior, and will also serve as an
important component in future UAV analysis.
Fig. 17. A map highlighting the 30 transects utilized during surveys of habitat structure.
-Orangutan/Primate Vocalizations
Graduate PhD student James Askew from the University of Southern California,
directed by Drs. Craig Stanford and Roberto Delgado, is seeking to better understand
orangutan social behavior and reproductive strategies, with an emphasis on how
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orangutans respond to male long calls. For his observations, Mr. Askew utilizes long call
playbacks and then evaluates how focal orangutans respond to the playback
experiments [Fig. 18]. This project proves to give us a better understanding of
Sumatran orangutan social behavior, as few researchers have attempted a study like
this on Sumatran orangutans.
Fig. 18. Graduate researcher from University of Southern California, James Askew, undertakes
a playback experiment at the Sikundur Monitoring Post. Photo courtesy of John Abernethy.
In addition to the playback experiments, Mr. Askew is also attempting to record primate
vocalizations, in order to better understand their function and also survey some of the
more unique primates within the area. For instance, white-handed gibbons
(Endangered), siamangs (Endangered), and Thomas’ leaf monkeys (Vulnerable)
regularly vocalize, most often nearest sunrise. Using audio recorders that are fitted with
a real time clock and GPS unit [Fig. 19], Mr. Askew will attempt to survey the three
aforementioned primates and then using spatial capture-recapture methods estimate
their local densities. This project will also serve a comparative dataset for the fixed
count vocal surveys that Helen Slater and Rosanna Consiglio will conduct on the same
three species (see below).
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A detailed look at Mr. Askew’s research and his journey through Indonesia can be
accessed via his Scientific American Expeditions blog –
(blogs.scientificamerican.com/expeditions).
Fig. 19. Two of SOCP’s assistants help to setup one of the audio reorders that were used during
audio surveys of gibbons, siamangs, and Thomas’ leaf monkeys. Photo courtesy of James
Askew.
-Gibbon, Siamang, and Leaf Monkey Surveys
In addition to their analyses of habitat structure at Sikundur, Helen Slater and Rosanna
Consiglio are also interested in evaluating the densities of three key primate species,
the white-handed gibbon (Endangered), siamang (Endangered), and Thomas’ Leaf
Monkey (Vulnerable). Using the fixed point call count methodology established by
Brockelman & Ali (1987) and Brockelman & Srikosamatara (1993), Ms. Slater and Ms.
Consiglio will conduct surveys at three listening arrays, each comprised of three
listening posts [Fig. 20]. The three arrays were set up in each of the three micro-habitat
types. Data recorded for each listening post includes the time of the group call, the
species, the compass bearing, and the estimated distance. Via triangulation, these data
can be used to estimate primate group densities and these densities will eventually be
evaluated relative to forest structure. These data will also serve a comparative dataset
for the audio data discussed above. This will be the first time that a comparison of these
survey methods will be undertaken for these primate species.
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Fig. 20. A map of the three fixed point vocal arrays that will be surveyed by Helen Slater and Rosanna
Consiglio, in their analyses of gibbon, siamang, and Thomas’ leaf monkey densities.
-Orangutan Nest Surveys
John Abernethy, a PhD student from Liverpool John Moores who is directed by Dr.
Serge Wich, is undertaking a detailed orangutan nest survey which will allow him to
calculate orangutan density estimates, and he will be trying to link the survey results to
that of habitat structure [Fig. 21]. Orangutan nest surveys rely on the fact that
orangutans construct nests daily, which are used at night and also sometimes during
the day for resting (van Schaik et al. 1995). Using nest counts instead of live encounters
with orangutans is often preferred due to the low density of orangutans, making density
estimates based on live encounters a very time consuming exercise. It also allows
researchers to systematically do repeat monitoring of a given area. This will be the first
time that the Sikundur area will be surveyed since the first surveys in early 2000s (Knop
et al. 2004).
As the Sikundur area was previously logged, Mr. Abernethey’s analyses are a key
component to understanding the behavioral strategies of orangutan populations in
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Sumatra’s degraded forest areas. Furthermore, given that the majority of lowland areas
housing orangutans in Sumatra are either completely deforested or highly degraded,
this project is highly important to current and future conservation strategies of Sumatran
orangutans.
Fig. 21. A photophragh of John Abernethy and a few of SOCP’s assistants undertaking orangutan nest
surveys.
VIII. Coming Up In 2015-2016
Given the successes of both the 2013 and 2014 field seasons, we are very much
looking forward to the 2015 field season. In addition to SOCP’s regular habitat and
orangutan monitoring activities, there are a number of new student projects from both
Bournemouth University and Liverpool John Moores University that will be started within
2015. Many of these will have a focus on local habitat structure and will attempt to
utilize the new technologies (e.g., UAVs) that we have been trying to develop over the
past couple of years. One project in particular is a detailed look at how canopy
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height/structure affects primate behavioral strategies, which is being conducted with the
help of Drs. Ross Hill, Amanda Korstjens, and Serge Wich. An example of this is shown
below [Fig. 22], which highlights the height of the canopy in relation to orangutan travel
paths. The preliminary findings seem to suggest that orangutans at Sikundur utilize
higher canopy areas more frequently than would be predicted by chance alone.
Fig. 22. A map of canopy height from the Sikundur monitoring post, with a
layer of orangutan travel paths on top. The shapefile is courtesy of Dr.
Ross Hill and Serge Wich.
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Given that the Langkat District is one of the most deforested areas in the Leuser
Ecosystem National Strategic Area and also one of the areas with the highest
incidences of human-orangutan conflict and poaching, the SOCP also seeks to develop
a greater capacity for conservation education, conflict mitigation, and local capacity
building in the Langkat area over the next couple of years. Our aims are to: 1) conduct
local village/school visits with relevant educational presentations; 2) enhance our ability
to help mitigate conflicts associated with Sumatran orangutans; and 3) support local
Indonesian students, as they pursue university degrees relevant to orangutan
behavioral ecology and conservation. The development of these three key activities is
set to begin in the second-half of 2015.
Lastly, with all of the projects that have been undertaken during 2013-2014, we at
SOCP are already working diligently on a number of key publications that will help to get
the word out about this unique lowland Sumatran rainforest habitat. We thank you for
your continued support and ask that you keep your eye out for these exciting future
publications.
IX. References Cited
Ancrenaz et al. 2014. Coming down from the trees: Is terrestrial activity in Bornean
orangutans natural or disturbance driven? Scientific Reports, 4(4924), 1-5. DOI:
10.1038/srep04024.
Brockelman WY, Ali R. 1987. Methods of surveying and sampling forest primate
populations. In: Marsh CW and Mittermeier RA (eds.), Primate Conservation in the
Tropical Rain Forest, Alan R Liss, New York, pp 23-62.
Brockelman WY, Srikosamatara S. 1993. Estimation of Density of Gibbon Groups by
Use of Loud Songs. American Journal of Primatology, 29, 93-108.
Cribb R. 1988. The politics of environmental protection in Indonesia. Centre of
Southeast Asian Studies, Monash University, Melbourne, Australia.
Hammer et al. 2013. FORMA Alerts. World Resources Institute and Center for Global
Development. Accessed through Global Forest Watch on 1 December 2014.
www.globalforestwatch .org.
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Hansen et al. 2013. High-resolution global maps of 21st-Century forest cover change.
Science, 342, 850-853.
Husson et al. 2009. Orangutan distribution, density, abundance, and impacts of
disturbance. In: Wich SW et al. (eds.), Orangutans: Geographic variation in behavioural
ecology and conservation, Oxford University Press. Oxford, pp 77-96.
Knop et al. 2004. A comparison of orang-utan density in a logged and unlogged forest
on Sumatra. Biological Conservation, 120,183-188.
Laumonier et al. 2010. Eco-floristic sectors and deforestation threats in Sumatra:
identifying new conservation area network priorities for ecosystem-based land use
planning. Biodiversity Conservation, 19, 1153-1174
Margono et al. 2012. Mapping and monitoring deforestation and forest degradation in
Sumatra (Indonesia) using Landsat time series data sets from 1990 to 2010. Environ
Res Lett, 7, doi:10.1088/1748-9326/7/3/034010.
Marshall et al. 2009. Orangutan population biology, life history, and conservation. In:
Wich SW et al. (eds.), Orangutans: Geographic variation in behavioural ecology and
conservation. Oxford University Press, Oxford, pp 311-326.
Morrogh-Bernard et al. 2009. Orangtuan activity budgets and diet. In: Wich SW et al.
(eds.), Orangutans: Geographic variation in behavioural ecology and conservation.
Oxford University Press, Oxford, pp 119-133.
Wich et al. 2008. Distribution and conservation status of the orang-utan (Pongo spp.) on
Borneo and Sumatra: How many remain? Oryx, 42(3), 329-339.
Wich et al. 2011a. Orangutans and the economics of sustainable forest management in
Sumatra. UNEP/GRASP/PanEco/YEL/ICRAF/GRID-Arendal, Indonesia.
Wich et al. 2011b. Forest production is higher on Sumatra than on Borneo. PLos ONE,
6(6), e21278. doi:10.1371/journal.pone.0021278
Wind, J. 1996. Gunung Leuser National Park: History threats, and options. In: van
Schaik C and Supriatna J (eds.), Leuser: A Sumatran Sanctuary. Yayasan Bina Sains
Hayati Indonesia, Indonesia, pp 4-27.
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van Schaik et al. 1995. Population estimates and habitat preferences of orangutans
based on line transects of nests. In: Nadler RD et al. (eds.), The Neglected Ape.
Plenum Press, New York, pp 129-147.
van Schaik et al. 2009. Geographic variation in orangutan behavior and biology. In:
Wich SW et al. (eds.), Orangutans: Geographic variation in behavioural ecology and
conservation. Oxford University Press, Oxford. pp 351-361.
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X. How to Get Involved
If you would like to make a donation or would like further information about our Sikundur project, please contact us: Matthew G. Nowak Director of Biodiversity Monitoring (SOCP) Email: [email protected] Dr. Ian Singleton Director SOCP Email: [email protected] Donations can also be made via Paypal online at: www.sumatranorangutan.org/research Follow all of our developments online at: www.sumatranorangutan.org
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