Final Report

Ecology, Distribution and Bio-acoustic of In Degraded Habitat (Part of Project: Ecology and Distribution of Amphibians and Slow Loris Primate in Degraded Habitat)

By: Hellen Kurniati Zoology Division, Research Center for Biology, Indonesian Institute of Sciences (LIPI) (Herps Ecologist)

Alex Sumadijaya Botany Division, Research Center for Biology, Indonesian Institute of Sciences (LIPI) (Plant Taxonomist)

Arjan Boonman Queen Mary University, United Kingdom (Wildlife Bio-acoustics)

Wahyu Tri Laksono Zoology Division, Research Center for Biology, Indonesian Institute of Sciences (LIPI) (Research Assistant)

Research Center for Biology Indonesian Institute of Sciences (LIPI) Ristek-Dikti Incentive Program 2010 Cibinong, November 2010 SUMMARY

To find out the diversity of on degraded habitats at elevation above 500 meters, three sites around the foothills of Mount Salak (Sukamantri, Curug Nangka area) were selected, namely Curug Nangka Waterfall River, irrigation ditch stream and pine plantation. A line transect survey methodology was used to assess frog diversity at the three study sites. During the transects, were also detected by means of listening to their vocalizations in addition to the visual assessment. The results of the seven day survey (27 May to 3 June 2010) and continued for another seven day survey (27 October-3 November 2010) 17 species of frog were found; they consisted of five families, including , Bufonidae, Microhylidae, Ranidae and Rhacophoridae. Along the 110 meter transect at Curug Nangka Waterfall River a maximum of seven species were found: seven species in first survey and five species in second survey, Rana hosii was dominant species in both surveys; however in this transect we found no association of frog species with plants around of river. Along 300 meter transect length at the irrigation ditch stream, eight species of frogs were found, Rana chalconota was dominant in the first survey, but the number lower in second survey. This shows that the impact of unusual fast flow water made the non-specialist species move to other places, whereas the fast water specialist including Bufo asper and macrodon were becoming dominant species. In this transect, strong association between plant and frog was shown between Rana chalconota and Brugmansia suaveolens, the low vegetation which grew along stream bank. Along 300 meter transect length in foot path of pine plantation, one frog species ( masonii) was found in first survey; however three frog species (Huia masonii, Rana chalconota and Bufo melanostictus) were found in second survey; however in this transect we found no association of frog species with plants around the foot path.

INTRODUCTION

The area of degraded land in Indonesia certainly will progressively increase, in line with the rampant deforestation that is taking place. The government's efforts in addressing degraded land so far only focused on the replanting of vegetation in the former concession, mining or clear cutting areas, without preliminary study on its effects on biodiversity. The species richness of fauna especially in the degraded area is lower compared to primary or secondary forest (Gardner, 2001), because most forest dwelling species cannot be found in the forest that has been converted by human activities (Inger and Lian, 1996). Generally, studies of amphibian diversity are usually only conducted in primary or secondary forest habitat, barely in disturbed forest. The aims of this study are to get data on ecological niche of each species found in degraded habitat and to find diversity of non-forest frog species that has adapted to degraded habitat area where close to secondary forest of Halimun-Salak National Park as a source of germplasm.

Survey Area

Figure 1. Location of study area on foot hill of Salak Mount, West Java (Red color). Source of map: Google Earth. 2 Location of the study was focused on the areas of degraded habitats on the foot hill of Salak Mount. The elevation of the survey sites are between 600-750 meters above sea level (asl) (Figure 1). The locations of transect sites can be characterized as follows:

1. Curug Nangka Waterfall River (S 60 40’ 14.0”; E 1060 43’ 29.8”; 640 m asl). Curug Nangka Waterfall River is a rocky bed river with strong moving water (Figure 2). The average width of the river was 5 meters; deep of the water was between 30-50 cm. A natural wall was situated on the right and left sides of the river with a height between 5-10 meters and the slope was almost 900. Vegetation in which the species of frogs found sitting or perching on stems or leaves were family Lamiaceae, family Thelypteridaceae, Garnotia acutigluma, Schismatoglottis calyptrata and Elatostema strigosum. To know distribution of frogs species along the river, 110 meter transect long was conducted at this site (maximum length of the river).

Figure 2. View of strong water current habitat at Curug Nangka Waterfall River (Photograph by A. Sumadijaya).

2. Irrigation ditch stream (S 60 40’ 14.0”; E 1060 43’ 29.8”; 640 m asl). The irrigation ditch stream was a stream canal from the Curug Nangka Waterfall River (Figure 3). The location of the irrigation ditch was an open area, with strong moving water and gravel riverbed. Width of the stream was between 40 cm - 100 cm; depth of water was between 30-50 cm. Height of cliff on the right and left sides were between 50-300 cm and the slope was between 100-900. The dominant plant on the stream bank was Brugmansia suaveolens. To know the distribution along the stream, a 300 meter long transect was conducted at this site.

Figure 3. Location of irrigation ditch stream (Photograph by A. Sumadijaya).

3. Pine Plantation (S 60 40’ 22.8”; E 1060 43’ 53.5”; 730 m asl). A line of the transect survey that was conducted on the foot path of pine plantation (Pinus mercusi) was to assess the diversity of terrestrial herpetofauna (amphibians and reptiles) (Figure 4). Distance of transect line from the river was about 50 meters. The width of the foot path was between 50-100 cm; the foot path was a 3 rocky land and slope of land of about 200. Lower vegetation that dominated this location was Piper aduncum and Nephrolepis exaltata. To know the distribution of herps fauna along the foot path, a 300 meter long transect was conducted at this site.

Figure 4. Foot path inside pine plantation where a 300 m long transect was conducted (Photograph by A. Sumadijaya).

METHODOLOGY

A. Transects: Based on Jaeger (1994), the purpose of the transect sampling method is to know relative abundance and densities across habitat gradients. This means that the method is very useful in determining intra-specific and inter-specific changes in amphibians populations across some continuously changing environmental feature.

1. Work along streams (use data sheet at Appendix 1) Select at least three streams. On each stream: a) Lay out a transect by marking stations with consecutive numbers (e.g., 0m, 10m, 20m, 30m etc.). Use red or yellow plastic flagging spaced 10 m apart; each transect must be at least 150 m (waterfall transect), preferably 300 m irrigation ditch transect). b) Walk each transect at night, collecting all frogs, lizards, and snakes seen. c) Record position of each specimen on transect by recording stream name, closest station number, position of relative to waters edge, and substrate (for example, on rock, on leaf of shrub, etc.). d) Identify the species of plant on transect.

2. Work in forest areas away from streams (use data sheet at Appendix 1) 2.1. Transects: a) Lay out transect 300 m long in pine plantation, beginning at least 50 m from the nearest stream, running approximately up-slope, and marked by stations spaced at 10 m intervals. a) Walk the transect at night, collecting all frogs, lizards, and snakes seen. b) Record the position of each specimen noting station number and position of each animal (e.g., on ground, under dead leaves, on shrub, on tree branch, etc.). c) Identify the species of plant on transect. d) Walk the transect at least once on each visit to the site.

Environmental data that recorded were air humidity, air temperature, water temperature and conditions of the moon (full moon, crescent moon or the dark moon) at each observation time. This data was used for ecological data of frog captures.

B. The diversity of frog: The Lighting Method was used in a variety of frog species. This method is effective to catch frogs at night by using a powerful flashlight to catch frogs. The frogs would be temporarily blinded by the bright light 4 in their eyes, making them easy to catch. Species abundance assessments followed Buden (2000) using the following terms: 1. Common (at least 30 sightings/day in suitable habitat and under optimal weather conditions). 2. Fairly common (10-30 sightings/day). 3. Uncommon (5-10 sightings/day on most survey days). 4. Scarce (up to 5 sightings/day, but possibly unrecorded more than half of survey days) 5. Rare (under 5 sightings on most survey days).

C. Vocalization During the transects, frogs were also detected by means of listening to their vocalizations in addition to the visual assessment. This means that species that vocalize loudly and frequently are overrepresented while quiet species are underrepresented in the survey results. Depending on local topography, typical detection distances of frogs can vary from 10 to >200m. The same methodology as for the lighting method was followed.

RESULTS AND DISCUSSION a. Transects: Results of frog diversity monitoring on abundance and distribution along transects (110 meter and 300 meter) that were conducted twice (in May and October 2010) are shown below: 1. Curug Nangka Waterfall River -First survey: Date of survey: 30 May 2010; air temperature: 24.80 C; water temperature: 20.20 C; humidity: 92%; moonlight: full moon; weather: cloudy sky, light rain. Transect length: 110 meter. 14 13

12

10

8

6

4 3 3 3

Jumlah individu 2 222 2 11 11

0 1234567891011 Sub-transek

Megophrys montana Bufo asper Huia masonii Limnonectes kuhlii Limnonectes macrodon Rana chalconota Rana hosii

Graphic 1A. Frog species diversity and their distribution along 110 m transect at Curug Nangka Waterfall River (May 2010).

-Second survey: Date of survey: 31 October 2010; air temperature: 24.10 C; water temperature: 19.00 C; humidity: 90%; moonlight: half moon; weather: clear sky. Transect length: 110 meter. 30 26 25

20

15

10 5 Jumlah individu 5 111 1 2 0 1234567891011 Sub-transek

Bufo asper Huia masonii Limnonectes kuhlii Rana chalconota Rana hosii

Graphic 1B. Frog species diversity and their distribution along 110 m transect at Curug Nangka Waterfall River (October 2010). 5 Along the 110 meter transect at Curug Nangka Waterfall River a maximum of 7 species were found: 7 species in first survey (Figure 1A) and 5 species in second survey (Figure 1B). Rana hosii dominated in both suveys. The habitat that has strong water current is typical habitat for R. hosii and Huia masonii (Kurniati, 2003; Liem, 1973). R. hosii was often found sitting on a rock at the edge or in the middle of the river, and rarely found sitting on a plant or among grassy on the riverbank. Along the transect, R. hosii most often found very common at sub-transect 11 (13 individuals and 26 individuals) where the waterfall occurred. This place was always wet by splashing water from the waterfall. H. masoni, the other strong water specialist spread fairly common in the transects (Figure 1A), however in the second survey, the number H. masonii was very low, only 2 individuals were at sub-transects 2 and 4 (Figure 1B). Two species were not found in the second survey, montana and Limnonectes macrodon. Most likely the absence of both species was caused by heavy rain that made water current of the river stronger than usual, so the frogs moved to other places or may have been drifted down river by water currents. Effect of strong water currents could also be seen from the reduced number of individuals of each species at the second survey. In this transect we found no association of frog species with plants around of river.

2. Irrigation ditch stream transect. -First survey: Date of survey: 28 May 2010; air temperature: 27.60 C; water temperature: 20.60 C; humidity: 69%; moonlight: full moon; weather: cloudy sky. Transect length: 300 meter.

5 4 4 3 3 2 2 2 2 2 2 11 1 1 11 1

Jumlah individu Jumlah 1

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Sub-transek

Bufo asper Leptophryne borbonica Huia masonii Limnonectes kuhlii Limnonectes macrodon Rana chalconota

Graphic 2A. Frog species diversity and their distribution along 300 m transect at irrigation ditch stream transect (May 2010).

-Second survey: Date of survey: 30 October 2010; air temperature: 23.10 C; water temperature: 18.10 C; humidity: 85%; moonlight: half moon, weather: cloudy sky, light rain (after heavy rain in late afternoon); color of water was brown (muddy water), water current was strong (stronger than water current in first survey). Transect length: 300 meter.

3

2 2 2

1111 11111 111 1

Jumlah individu Jumlah 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Sub-transek

Bufo asper Limnonectes kuhlii Limnonectes macrodon Rana chalconota Rana nicobariensis Bufo melanostictus

Graphic 2B. Frog species diversity and their distribution along 300 m transect at irrigation ditch stream transect (October 2010).

Along 300 meter transect length at the irrigation ditch stream, 8 species of frogs were found (Figure 2A and 2B), however 2 species were not found in second survey (Leptophryne borbonica and H. masonii) and 1 species was not found in first survey (Bufo melanostictus). Two species (H. masonii and L. kuhlii ) only 6 occurred at the beginning of irrigation ditch and the end of waterfall river transect; it showed that the two species could not inhabit open area that occurred along irrigation ditch stream. The number of individuals of each species was lower in the second survey (Figure 2B). Rana chalconota was dominant in the first survey (Figure 2A), but the number lower in second survey. This shows that the impact of unusual fast flow water made the non-specialist species move to other places, whereas the fast water specialist including Bufo asper and L. macrodon were becoming dominant species. In this transect, strong association between plant and frog was shown between R. chalconota and Brugmansia suaveolens, the low vegetation which grew along stream bank.

3. Pine plantation. -First survey: Date of survey: 1 June 2010; air temperature: 27.00 C; humidity: 72%; moonlight: half moon; weather: cloudy sky and mist. Transect length: 300 meter. 3

2

1 jumlah individu jumlah

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Sub-transek

Huia masonii Bronchocela cristatella Bronchocela jubata Tachydromus sexlineatus Cyrtodactylus sp Hemidactylus frenatus Leopeltis tricolor

Graph 3A. Herpetofauna species diversity and distribution along 300 m transect at pine plantation area (June 2010).

-Second survey: Date of survey: 27 October 2010; air temperature: 22.40 C; humidity: 81%; moonlight: half moon; weather: cloudy sky, after heavy rain in late afternoon. Transect length: 300 meter. 2

1 jumlah individu jumlah 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Sub-transek

Huia masonii Bronchocela jubata Cyrtodactylus sp Rana chalconota Bufo melanostictus

Graph 3B. Herpetofauna species diversity and distribution along 300 m transect at pine plantation area (October 2010).

Along 300 meter transect length in foot path of pine plantation, 1 frog species (H. masonii) was found in first survey (Figure 3A); however 3 frog species (H. masonii, R. chalconota and B. melanostictus) were found in second survey (Figure 3B). One individual of H. masonii in the first survey was found around a leaking water pipe that splashed water, so the habitat around the pipe was always wet. It seemed to be that the effect of low air temperature (22.40 C) and high humidity (81%) in the second survey caused several frog species to move to other places to avoid the strong water currents of the river after heavy rain. The number of reptile species that found on the first survey was 6 (Figure 3A), whereas 2 species were found in the second survey (Figure 3B). Distribution of the reptiles was not random; in the first survey, reptiles were not found along sub transect 5-19; however in the second survey no reptile was found along sub transect 16-30. The main factors that caused the non-random distribution of reptiles in the two surveys are still unknown. 7 b. The diversity of frog species During the 7 day survey (27 May to 3 June 2010) and continued for another 7 day survey (27 October-3 November 2010) in the area around the foothills of Mount Salak (Sukamantri, Curug Nangka area), 17 species of frog were found; they consisted of 5 families, including Megophryidae, Bufonidae, Microhylidae, Ranidae and Rhacophoridae. Family Megophryidae consisted of 1 species, Megophrys montana. Family Bufonidae consisted of 4 species, including Bufo asper, B. biporcatus, B. melanostictus and Leptophryne borbonica. Family Microhylidae consised of 1 species, Microhyla achatina. Family Ranidae consisted of 9 species, including Huia masonii, F. cancrivora, F. limnocharis, Limnonectes kuhlii, L. macrodon, L. microdiscus, Rana chalconota, R. hosii and R. nicobariensis. Family Rhacophoridae consisted of 2 species, including Polypedates leucomystax and Rhacophorus reinwardtii. A description of the 17 species that were encountered during the surveys is given below:

A. Family Megophryidae 1. Megophrys montana (Figure 5) This species is a terrestrial frog. It was encountered on the waterfall transect site. Only one individual was found along 110 meters transect length. This frog was found sitting on the rock that was covered by moss at the edge of the river at about 50 cm height above the water surface (Figure 5). Habitat at the transects was strong-flowing water. This type of habitat is not the main habitat of M. montana, because this frog is a forest floor litter dweller (Kurniati, 2003). The presence of M. montana on the site was unusual. Probably it was carried away by the strong flowing water from upstream of the Curug Nangka Waterfall.

Figure 5. Megophrys montana (Photograph by A. Sumadijaya).

B. Suku Bufonidae 1. Bufo asper (Figure 6) This species is a semi-aquatic frog. It was encountered rarely on the waterfall transect site, and found a lot on the open irrigation ditch transect. In the irrigation ditch transect, the frog was often found on the ground sitting in the herbaceous vegetation at the edge of the waters; however on the waterfall transect, this frog was often found sitting on the wet rocks at the riverbank. The presence of B. asper in its habitat can be inferred from its distinctive call that is often produced either by day and night.

Figure 6. Bufo asper (Photograph by A. Sumadijaya). 8

Figure 6A. Sound spectrogram of Bufo asper.

The basic elements of the vocalization of Bufo asper are a pure tones (900-1200 Hz) and calls consisting of impulses (carrier frequency: 700-800 Hz) (Figure 6A). The impulsed call consists of about 13-15 impulses, slowly disappearing into noise due to decreasing call intensity. The repetition rate of the impulses is about 160 Hz. There appears to be little or no audible sensation of repetition pitch to the human ear, even not at close range. However, the roughness of the impulse calls is apparent. Impulse call duration is about 80 ms. Pure tone duration about 80-100 ms. The pure tone is usually followed by the first impulsed call after about 320-400 ms and a second impulsed call is produced about 450-550 ms after that. Sometimes, only 1 impulsed call is produced after the pure tone. Single, very quiet impulsed calls may also be produced. The amplitude of the three calls can differ by more than 6 dB and the loudness of the calls appears to vary randomly. The sequence of three calls is repeated at intervals of 2.5-3 seconds during active calling bouts, but may become minutes during inactive phases.

2. Bufo biporcatus (Figure 7) This species is a terrestrial frog. The frog was not found at waterfall, irrigation ditches or at pine plantations transects. This toad was found in the flooded waters close to human settlements and often also found on the forest edge (Kurniati, 2003). This species was also found many at the wetland area of Ecology Park, especially during full moon nights (Kurniati, 2010). Adult males of this species usually call at the dry water edge, whereas when they are away from the water, frogs are usually keep silent and tend to be solitary.

Figure 7. Bufo biporcatus (Photograph by A. Sumadijaya).

9

Figure 7A. Sound spectrogram of Bufo biporcatus.

The basic elements of the vocalization of Bufo biporcatus are relatively long (max 20 ms) impulses having a clear 2nd and 3rd (strongest) harmonic. The first harmonic (fundamental) is at around 700 Hz and possibly slightly weaker than the 3rd harmonic (Figure 7A). The second harmonic is the weakest (about 6 dB lower in intensity than the other two). It remains unclear how such a sharp filtering / amplification can take place in the frog’s vocal apparatus. It could be argued that the impulses are in fact pure tones of very short duration; however no clear physical definition exists for either of the two. The carrier frequency of the impulse (700 Hz) and harmonics define the timbre of the vocalization. However, the vocalizations of this species, to the human ear, have a characteristic roughness, which one could describe as having an r-sound, or rattling quality. This quality is the effect of amplitude modulation (AM). Two strong impulses are usually separated by 10-12 ms, or from peak to peak: 25-30 ms. Just two consecutive impulses are already sufficient to cause the rattling sensation. To the human auditory system, the sensation persists at half the replay speed, but the sound is interpreted as two consecutive tones at ¼ the normal replay speed. It is unknown how frogs process these sounds, but the double impulsed sound may be important in species recognition by conspecifics. The intervals between the double clicks are typically 30-35 ms. More recordings of single individuals are needed to study the vocalizations in more detail.

3. Bufo melanostictus (Figure 8) This species is a terrestrial frog. It was not found at waterfall, irrigation ditches and pine plantations transects. This toad is common around human settlements or habitats were created by humans. This species was also found in the wetland area of Ecology Park, but encountered only few individuals (Kurniati, 2010), because the toad does not like wetland habitat except in mating season.

Figure 8. Bufo melanostictus (Photograph by A. Sumadijaya).

10

Figure 8A. Sound spectrogram of Bufo melanostictus.

The sound of Bufo melanostictus consists of two clear harmonics: the first one at 1450 Hz, the second at 2900 Hz, both having very little bandwidth (Figure 8A). To establish what the basic elements of the vocalization are, this species needs to be recorded in an echo-free environment. In the present recordings in our database, repeated elements are separated by 50-70 ms. However, each element, in turn, also appears to be amplitude modulated, hence consisting of impulses at a fairly random repetition rate. Even the smallest elements in our recordings, tones of 1450 Hz and 40 ms, also show amplitude modulations, but these may have easily resulted from interference due to reflections from nearby walls. Again, the sound has the characteristic Bufo-roughness due to the amplitude modulation.

4. Leptophryne borbonica (Figure 9). This species is a semi-aquatic frog. It was encountered rare at the irrigation ditch transect. The main habitat of the frog is slow-moving and shallow waters. The frog was not found on the main stream, but at slow- moving water ditch tributary where overgrown herb was not dense.

Figure 9. Leptophryne borbonica (Photograph by A. Sumadijaya).

C. Family Microhylidae 1. Microhyla achatina (Figure 10) This species is a semi-aquatic frog. It was not found at waterfall, irrigation ditches and pine plantations transects. In Curug Nangka area, the frog was found in pine plantation area of about 30 meters from the irrigation ditch transect (Figure 10). The frog was also found in the wetlands area of Ecology Park where Axonopus compressus was dominant; however in Gunung Halimun National Park, the frog was found abundant around rice field area (Kurniati, 2003).

11

Figure 10. Microhyla achatina (Photograph by A. Sumadijaya).

Figure 10A. Sound spectrogram of Microhyla achatina.

Microhyla achatina produces series of impulses, each lasting 5-6 ms, spaced at intervals of about 50 ms. Each series (call) lasts about 360 ms. Under normal conditions, the intervals are the same throughout a call. However, in very active phases, the last couple of impulses are delivered at intervals of only 20 ms. The impulses have a special quality, despite their short duration. The second harmonic of each impulse, at 3 kHz is dominant, whereas the first and third are suppressed (Figure 10A). Individuals with the second harmonic at 2.4 kHz have also been recorded. The bandwidth of the dominant harmonic is only 1 kHz (FFT size: 512 points). This is a remarkable accomplishment since each impulse may only consist of 7-9 periods. Echo-free recordings are needed to measure the duration-bandwidth product faithfully. Intervals between series (calls) last 2-3 seconds during active phases.

D. Family Ranidae 1. Huia masonii (Figure 11). This species is an aquatic frog. It was found quite common at waterfall transect site, but was not found at irrigation ditch transect. The frog preferred such shallow, rocky and fast-moving water habitat. Females of this species were rarely found in riparian habitat, excepted in the mating season (Figure 11, left). In the pine plantation transect, a female of H. masonii was found sitting on wet pine litter that located about 100 meters from the river (Figure 15, right).

12

Figure 11. Huia masonii in amplexus position (left), found at waterfall transect site; female of H. masonii, found at pine plantation transect (right) (Photograph by A. Sumadijaya).

Figure 11A. Sound spectrogram of Huia masonii.

Single pure calls, sometimes with harmonics of varying frequency. Each call is rapidly frequency modulated (FM), exhibiting different patterns, such as V, W, inverted U or downward sweeps, each time with a different pattern (Figure 11A). The lowest frequency of such calls measured was 4.5 kHz (with prominent harmonics) and the highest 16.5 kHz, already close to the human upper limit of hearing. The second harmonic of the high calls is completely ultrasonic. Duration of the calls is around 6-19 ms. Due to nonlinearity of microphones it cannot be established how much lower in amplitude the second harmonic is, but it is definitely more than 10 dB weaker than the first. This implies that communication takes place by using the first harmonic only. Short “buzzes” are also produced by Huia masonii. The buzz consists of about 5-9 impulses, each with a duration of about 10 ms, 15 ms apart. Each impulse consists of 3 harmonics, the first at 3.5 kHz. It looks as if shifts can take place within buzzes from low to higher frequencies, reminiscent of formant filtering, but further investigations are required to clarify this issue. The frogs seem to answer each other in active calling bouts. However, as much as an hour may pass between calling bouts.

2. cancrivora (Figure 12) This species is a semi-aquatic frog. It was not found at the waterfall, irrigation ditches and pine plantations transects. The frog is common in rice fields (Kurniati, 2003) or stagnant waters dominated by grassy plants. The frog is hunted for human consumption. A frog hunter that lives in Tapos Village usually can harvest the frog from rice fields for about 30 kg per week; however 5 years ago the harvest could reach 50 kg per week (Figure 12). Reducing of the harvesting number indicates that the population of F. cancrivora at the foot hill of Mount Salak area is decreasing.

13

Figure 12. Fejervarya cancrivora (Photograph by A. Sumadijaya).

3. Fejervarya limnocharis (Figure 13) This is a semi-aquatic frog. It was not found at waterfall, irrigation ditches and pine plantations transects. The frog usually was found common at the habitats with grasses as the dominant plant. This species was sometimes found on grassy field that far from the waters (Figure 13), but the frog becomes dominant in rice fields when F. cancrivora decreased in number (Kurniati, 2003). This species is also harvested by humans; however due to the small of body size, the frog is commonly used as food of Arowana fish.

Figure 13. Fejervarya limnocharis (Photograph by A. Sumadijaya).

Figure 13A. Sound spectrogram of Fejervarya limnocharis.

The human auditory perception of the vocalizations produced by this frog species is completely dominated by pulse repetition pitch. The first harmonic of this species (defining the perception of pitch) is at 1.1 kHz (Figure 13A). This is the same frequency as used by Bufo asper in producing the pure tone. However, playing this tone results in a perception of a much higher frequency than playing the sounds of Fejervarya limnocharis. This effect is due to the fact that the human hearing system interprets a rapid series of impulses as 14 a single tone with a certain pitch. The pitch corresponds to the pulse repetition rate which is about 110 Hz in the species. Although humans perceive this frog as having a frequency close to the human male voice, its carrier (true) frequency that is measured in spectrograms is in fact 10 times higher. Fejervarya limnocharis also revealed another surprise: the two “harmonics” the species produces are not exactly related by a factor of two. The first “harmonic” is consistently at 1.1 kHz, but the second at 2.5-2.6 kHz, instead of 2.2 kHz! The cause for this phenomenon is subject of investigation. The basic elements of the vocalization are impulses of 5-6 ms, repeated at 9.5 ms intervals. Each call typically lasts 110-150 ms. Intervals between calls last 50 ms half a second during active calling periods.

4. Limnonectes kuhlii (Figure 14) This species is an aquatic frog. It was found quite common at waterfall transect. The preferred habitat of this frog is slow-moving muddy stream or slow-moving rocky stream. At the waterfall transect, this frog was usually found on slow-moving water along the river bank.

Figure 14. Limnonectes kuhlii (Photograph by A. Sumadijaya).

Figure 14A. Sound spectrogram of Limnonectes kuhlii.

Extremely soft calls (50 ms), repeated at 10 minute intervals. Main intensity at 2.7 kHz (Figure 14A). The call consists of many impulses and the AM dominates the perceived pitch of this call, which sounds much lower than 2.7 kHz. Further description difficult due to low quality of recordings.

5. Limnonectes macrodon (Figure 15) This species is a semi-aquatic frog. Rarely encountered in the irrigation ditch transect or waterfall transects. The preferred habitat of this frog was rocky and fast-flowing waters. In both transects, the adults individual were not encountered, only juveniles and sub-adults were found. This species commonly consumed by humans, possibly at the two transect locations, adult individuals have been hunted by local residents. The frog was often found sitting on the stone at the waterfall transects or on the ground in the irrigation ditch transects.

15

Figure 15. Limnonectes macrodon (Photograph by A. Sumadijaya).

6. Limnonectes microdiscus (Figure 16) This species is a are semi-aquatic frog. The frog was not found along waterfall, irrigation ditch or pine plantation transects, but found at the temporary stream in the edge of pine plantation around Curug Nangka area after heavy rains. The main habitat of this frog is wet forest floor with thick litter. The presence of this frog in temporary stream was likely to be a consequence of it being carried away by the rushing flow of water due to heavy rains.

Figure 16. Limnonectes microdiscus (Photograph by H. Kurniati).

Figure 16A. Sound spectrogram of Limnonectes microdiscus.

Calls are about 130-160 ms in duration, sweeping upwards slowly from 750 to 1000 Hz (Figure 16A). Each call appears to consist of a pure tone, shallowly amplitude modulated by about 90 Hz. Still, the roughness due to the AM is clearly audible to the human ear. The second harmonic is only 4 dB less strong at the start of the call, but looses in power quickly, becoming about 16 dB weaker relative to the first harmonic. Very likely, the second harmonic enters a filtered zone above about 1600 Hz, suppressing the second harmonic. During

16 active phases, calls follow each other at 1.2-1.5 second intervals. The frog can be hard to localize and appears extremely sensitive to disturbance including light. The calls of this species are comparatively weak.

7. Rana chalconota (Figure 17). This species is included in the group of semi-arboreal frogs. It was found quite commonly along the waterfall transect and was very common at the irrigation ditch transect, especially at the open stream bank with many herbs grown on the edge stream. The frogs were often found sitting on herbaceous plant Brugmansia suaveolens at the waterfalls and irrigation ditch transects. This frog was sitting on the herbaceous plant at the height between 30 cm to 3 meters from the surface of the water.

Figure 17. Rana chalconota (Photograph by A. Sumadijaya).

Figure 17A. Sound spectrogram of Rana chalconota.

The song of Rana chalconota is far more complex than of any of the other frogs (Figure 17A). It is very quiet and probably serves for short distance communication only. The song is more complex than that of many birds and may consist of impulse series with a first harmonic at 1 kHz, but also pure tones, with a first harmonic at 3 kHz and all frequencies in between. The pure tones may be frequency modulated. Pure tones are most commonly encountered and they appear to have a varying harmonic content. Some are strongly AM and therefore sound scratchy, whereas other tones sound like whistles. The song is more or less continuous and elements are probably never 100% identical.

8. Rana hosii (Figure 18). This species is an aquatic frog that inhabits strong-flowing waters. The frog was found abundant and dominated the waterfall transect. Along the transect, the preferred habitat was always wet stone on the riverbank. This frog could be sitting on a steep rock at the edge of the river at of about 5 meters high from the water surface. This species was rarely found sitting on a plant on a steep section of the river wall.

17

Figure 18. Rana hosii (Photograph by A. Sumadijaya).

Figure 18A. Sound spectrogram of Rana hosii.

Multiple harmonic down sweeping calls, typically from 7 to 2.9 kHz in 40-45 ms (Figure 18A). 2.6 kHz, less modulated calls have also been recorded. Within the 40 ms, only 5-15 ms may be of high amplitude. The suitability of these calls to communicate near rushing streams is very questionable. It is possible that this species limits its communication to short distances.

9. Rana nicobariensis (Figure 19). This species is a semi-arboreal frog. The frog was not found along waterfalls, irrigation ditch and pine plantation transects. This species inhabits stagnant waters where herbaceous plants are dominated the area; it is also common in the rice fields (Kurniati, 2003) or open wetlands such as the available habitat in the "ecology park" (Kurniati, 2010). Adult male usually calls at night or during the day.

Figure 19. Rana nicobariensis (Photograph by H. Kurniati).

18

Figure 19A. Sound spectrogram of Rana nicobariensis.

Rana nicobariensis produces sounds with very similar principles to the human voice. As in the human voice, the basic elements are impulses. In the human female voice, the first harmonic is at 200 Hz, in R. nicobariensis at 400 Hz. Harmonics span over a frequency range from 1.2 to 5.5 kHz (Figure 19A). Unlike in humans, the first 3 harmonics are suppressed. Similar to human vowel production, frequency zones of high intensity (formants) are visible in R. nicobariensis. In the frog the “vowel” is always the same one with energy at 1.4 kHz and in between 3 and 4 kHz. Each call lasts about 45-50 ms. Each call consists of a series of about 18 impulses, delivered at a rate of about 280-290 Hz. The rate, however, is not entirely constant which destroys the human perception of pulse repetition pitch, as present in Fejervarya limnocharis. Secondly, the impulses are remarkably variable in shape, which also destroys repetition pitch to some extent. Impulse variation also introduces the “kgggg”, or noisy character of the sound. The timbre of the sound is not entirely noisy, but also has an impulsive character. It remains unclear how the variability in impulse structure in a series is generated by the frog to cause exactly the noisy, but pulsating timbre that it does. Calls are separated by about 120 ms and about 4 to 12 are produced in a row. We still lack clear recordings of single individuals to establish how often the series of repeated calls occur per time unit and also to study in more detail the variation of the impulse function.

E. Family Rhacophoridae 1. Polypedates leucomystax (Figure 20). This species is an arboreal frog. The frog was not found at waterfall, irrigation ditch and pine plantation transects. It is generally found in human settlements or man-made habitats, and also in the area of forest edge (Kurniati, 2003). This species is also found in the area of "ecology park" but found to be uncommon (Kurniati, 2010).

Figure 20. Polypedates leucomystax (Photograph by A. Sumadijaya).

19

Figure 20A. Sound spectrogram of Polypedates leucomystax.

The basic elements of the vocalization of Polypedates leucomystax are impulses with a duration of 3 ms and a carrier frequency of 1.9 kHz (Figure 20A). This frequency may in fact be a second harmonic of a fundamental of 950 Hz. The impulses are delivered at a rate of 95 Hz (intervals: 6-15 ms). As in Fejervarya, repetition pitch defines the frequency as perceived by the human ear completely: the sound does not sound high, but rather similar in frequency to a human male voice (100 Hz). Still, the perceived pitch may sound rough and wideband due to irregularities in the intervals between impulses. One call lasts about 150-200 ms and consists of about 13-15 impulses, decreasing in amplitude at the end of the call. Series of low-amplitude impulses, separated by 10-12 ms may be interspersed in between calls. During active phases, calls are repeated every 12- 30 seconds. The amplitude onset of each impulse is very rapid. The decay time and exact duration must still be measured in an echo-free environment.

2. Rhacophorus reinwardtii (Figure 21) This species is an arboreal frog. The frog was not found at waterfall, irrigation ditch and pine plantation transects; however it was found in banana plantation that closed to human habitant. It is generally found in human settlements or man-made habitats, and also in the area of forest edge where quiet pools are available (Kurniati, 2003).

Figure 21. Rhacophorus reinwardtii (Photograph by H. Kurniati).

20

Figure 21A. Sound spectrogram of Rhacophorus reinwardtii.

The basic elements of the vocalization are Gabor-like impulses with a bandwidth of about 1.3 kHz (1- 2.3 kHz) and a duration of about 2-4 ms with no higher harmonics (Figure 21A). 4-6 periods occur within one impulse. Impulses can occur in a series of 4 (intervals 6-8 ms) but also singly. Humans cannot resolve the individual impulses at 7 ms intervals, but the rapid AM lowers the sensation of pitch of the carrier frequency. A frequently uttered sequence by R. reinwardtii is an impulse followed 160 ms later by 3 impulses in rapid succession (4 ms intervals), then a pause of 190-200 ms followed by another series of 3 impulses (6 ms intervals). Sometimes such a series culminates in an extra series of impulses, separated by about 130 ms and hence discernable by the human ear. Many variations on this theme are used. The interesting remaining questions are how the frog is able to generate such perfect narrow bandwidth Gabor impulses and if the temporal resolution of this frog is superior to ours.

REFERENCES

Buden, D.W. 2000. The reptiles of Pohnpei, federal States of Micronesia. Micronesica 32 (2): 155-180. Gardner, T. 2001. Declining amphibian populations: a global phenomenon in conservation biology. Animal Biodiversity and Conservation 24 (2): 25-44. Inger R. F and R. B. Stuebing. 1989. Frogs of Sabah. Sabah Park Publication No. 10. Kota Kinabalu. Inger, R.F and T.F. Lian. 1996. The natural history of amphibians and reptiles in Sabah. Natural History Publication (Borneo). Kota Kinabalu. Jaeger, R.G. 1994. Transect sampling. In : Heyer, W.R., M.A. Donnely, R.W. McDiarmid, L.C. Hayek and M.S. Foster (editors). Measuring and monitoring biological diversity, standard method for amphibians. Pp. 103-107. Smithsonian Institution Press. Washington. 364 pp. Kurniati, H. 2003. Amphibians and reptiles of Gunung Halimun National Park, West Java, Indonesia. Research Center for Biology-LIPI. Cibinong. Kurniati, H. 2010. Keragaman dan kelimpahan jenis katak serta hubungannya dengan vegetasi pada lahan basah “Ecology Park”, Kampus LIPI Cibinong. Berita Biologi (in press). Kurniati, H., W. Crampton, A. Goodwin, A. Locket and S. Sinkins. 2000. Herpetofauna diversity of Ujung kulon National Park: An inventory results in 1990. Journal of Biological Researches 6 (2): 113-128. Liem, D.S.S. 1973. The frogs and toads of Tjibodas National Park Mt. Gede, Java, Indonesia. The Philippine Journal of Science 100 (2): 131-161.

21 Appendix 1. Data sheet for transect method.

Date : ...... Air temperature :…...... 0C Water temperature : …………...... ……0C Recorder : ...... Humidity : ...... %

Moon shine : ...... GPS position : ......

Position and distance from water Number (+) out of water…...... cm Transect Species of Habitat (-) in water…...... …cm individual (↑) height from ground...... cm

Page ……………………… Notes ………………………………………………………......

22