Ecology, Distribution and Bio-Acoustic of Amphibians in Degraded Habitat
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Final Report Ecology, Distribution and Bio-acoustic of Amphibians 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 frog species 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, frogs 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 Megophryidae, 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 Limnonectes 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 (Huia 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 amphibian 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 animal 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.