Danced Management of Maliau Basin Conservation Area Sabah, Malaysia TECHNICAL ASSISTANCE REPORT No. 38 LAKE LINUMUNSUT (I)The Herpetofauna and Freshwater Fishes of Linumunsut Lake, Maliau Basin, Sabah (II) Diversity and Abundance of Birds Community at Linumunsut Lake, Maliau Basin, Sabah April 2002 Authors: Maklarin lakim, Alim Biun & Paul Yambun Sabah Parks, Research & Education Division P.D.Box 10626, M& 88806 Kota Kinabalu, Sabah, Malaysia. Phone +60 88 211881, Fax +60 88 211001 Hans Skotte Moeller Drnis Consult ltd., Vesterbrogade 140,2 DK 1620 Copenhagen V, Denmark Phone: + 4533318464 Fax: + 4533247599 E-mail: [email protected] THE HERPETOFA UNA AND FRESHWATER FISHES OF LINUMUNSUT LAKE, MALIAU BASIN, SABAH. Maklarin B.Lakim & PaulYambun Researchand EducationDivision SabahParks. ABSTRACT. Abundance and diversity of reptiles, amphibians and freshwater fishes in LinumunsutLake and its surroundingareas were surveyed.Sixteen species of reptiles,32 speciesof amphibian and 8 speciesof freshwaterfishes were obtained from various survey techniques employedduring the fieldwork. Herpetofaunaof Linumunsutare representativeof the Bornean lowland forests species.A majority of the amphibianspecies are primary forest inhabitants.The freshwaterfishes representedfish communitiestypical to rivers and streamsin the westernpart of Sabah.The record of speciescomposition is slightly greaterthan that from previous surveys in interior parts of Maliau Basin ConservationArea. This showsthe outstandingvalues of the Maliau Basin ConservationArea in tenns ofherpetofaunaand freshwaterfishes communities. 1. INTRODUCnON The Maliau Basin Conservation Area is a pristine wilderness region located in the remote south central part of the state of Sabahin Malaysia. Covering some 58,840 hectares, the area encompasses a diverse assemblage of forest types, comprising mainly lower montane forest, rare montane heath or kerangas forest, lowland and hill dipterocarp forest. The variation of vegetations occurring at different elevations in the Maliau terrain as well as the isolation caused by its land formation create a unique environment that allows various fauna and flora to flourish in abundance(see Marsh, 1989; Maryati et al., 1998). Several field studies on the abundanceand diversity of herpetofauna and freshwater fishes have been carried out in Maliau Basin. Previous related research activities concentrated more on the higher elevation areas that included montane and heath forest habitats. Inger (pers. comm.) has collected information on the occurrence of amphibian species at 450 m a.s.l and 750 m a.s.l. in the Maliau Basin. He also recorded reptiles encountered during the course of his study here. The 1988 scientific expedition provi~ed documented data on freshwater fishes at localities ranging from 450 m a.s.l. to 950 m a.s.I.(Marsh, 1989). The subsequent scientific expedition in 1996 has yielded additional discoveries on amphibian fauna (Ahmad & Wong, 1998) as well as freshwater fishes ~d crustaceans (Martin-Smith et al., 1998). However reptiles was not reported during this expedition. LinumunsutLake is also a potentiallyimportant sampling sites as the areahas nqver been sampledbefore for herpetofaunasince the 1978 faunal survey conducted by the Wildlife Section, SabahForest Department.Their preliminaryfindings indicated that the areaharbored large abundanceand diversityof reptiles and amphibiansthough encounfers were scarceor not compherensivelyreported. Among other specieshighlighted incluped giantpond turtle. Howeverdue to lack of intentionand expertise in identifyingherpetof~na itself amongthe expeditionmembers their list was very limited. This survey aims to document the diversity and abundanceof reptile, amphibian ~d freshwater fishes in Linumunsut Lake and its surrounding areas.The findings will contriQute 2 to the establishment of a more compherensive checklist of herpetofauna and freshwater fishes from Linumunsut Lake in particular and additional data to the existing checklist of its kind in the Maliau Basin Conservation Area as a whole. 2. STUDY SITE Linumunsut Lake at an elevation of 400 m a.s.l. is located in the northern portion of the Maliau Basin Conservation Area (Figure 1). The study site was concentrated within the 11.77 hectareslake its surrounding areas.Coverage is estimated 20 ha. The soil found in the area is categorized as the Maliau sandstone association distinctively characterized by its poor soil nutrient content and easily eroded, as a result, occurrence of heavy flooding and landslides were common in the area. The vegetation comprised mainly lowland dipterocarp rain forest although some patches of old secondary forest were found flourishing amid the forest. Open areas are also available along the edge of the lake. Riparian habitats are abundance in the surroundings of the lake including the largest river flowing from the lake, Sungai Namatoi. The terrain of our work included flat areas, areas with moderate to steep gradients and swampy areas with stagnant or little flowing water. Sampling activities were carried out in four major locations: i.e. out flowing streams from the lake, the Sungai Namatoi, swampy area and forest floor. The Sungai Namatoi flowed with strong current over rocky beds and boulders and had steep gradient. Streams flowing out of the lake had moderate gradient, and were permanent, clear and rocky with moderate current. Stream widths were estimated at 15-25 m. Forest floor within 10-1000 m from the edge of the lake is covered by tall secondary forest and primary forest with 75-100 % canopy coverage. 3. MATERIALS AND METHODS Data collection in the field involved 4 techniques namely; stream transects, forest transects, floor quadrats and fish and tadpoles sampling. These are standardtechniques: for inventory and monitoring ofherpetofauna (Heyer et al., 1994). These techniques condu91ed at day and night time involved four fieldcrews. Stream Transects were done at night commencing at 1900- 2100 hIs. Fieldcrfws with head-lamps searchedalong stream or edge of lake. Individual adult reptiles and frogs were located by their eyeshine with source of light from headlamps. The adult reptiles and frogs encountered will be recorded to its species. Microhabitats for each individual encountered were recorded such as substrate, distance from water, height above watef or ground and type of aquatic habitat. Unidentified reptiles and frogs on the spot were taken as a specimen for further identification in the laboratory. Attempts were also made to ideqtify amphibians by its conspicious calling. Forest Transects is similar to the Stream Transect rut, this method ran in the forest instead of a stream. ' Floor Quadrats of 5m x 5m were carried out in the morning at 0900 until 1330 Prs. A minimum of 4 persons required to do this method. The site of every quadrat were selected randomly. Canopy cover, floor cover/ litter and number of trees> 1 Ocm dbh in~ide the quadrats were recorded. Floor litter then cleared in search of reptiles and amphibi~s. 3 Any specimensencountered were caught and recorded. Similarly, tree buttresses with trunk diameter measurements between 40 cm to 200 cm were searched for any reptiles and amphibians.All specimenswere caught manually. Fishes were captured using a cast net in the lake and streamswide and deep enough to allow casting. In addition, hook and line were also use to catch fishes. These procedures were conducted in the afternoon between 1430 and 1630 hrs. Various aquatic microhabitats such as torrent, rime, side pool and open pool along the selected stream and within the lake were sampled. Tadpoles sampling conducted at the same time and locality using smaller sized nets. Fishes and tadpoles collected were identified (to its species),staged and released. The tadpoles that could not be identified on the spot were taken as specimens for further identification in laboratory. Specimens collection were limited to a maximum 5 representative individuals of each speciesof herpetofauna and freshwater fishes. Each specimenwas put in a small plastic bag, tagged, identified and weighed. All specimenswere preserved in 10% formalin and stored later in 75% alcohol. Unidentified specimenswere taken to SabahParks Museum at Kinabalu Park for further identification in laboratory. 4. RESULTS AND DISCUSSIONS 4.1 Reptiles A total of 15 species of reptiles were recorded throughout the survey which included snakes and lizards (Table 1). 9 species of lizards from 3 families and 6 species of snakes from 3 families were encountered mostly in tree buttressesand forest floor quadrats. The lizard family Scincidae was commonly encountered bearing a total of 5 species. The reptiles utilized various forest substrates such as in tree holes, under litter of dead leaves, on the branches of trees or on tree trunks above ground. Surveys of reptiles in the Maliau Basin area were not extensively carried out in previous expeditions. Our surveys attempted to collect as many species of reptiles as possible during the one week field trip. Sightings of snakes swimming or crossing the lake were common but samplingdetermination about of thetheir same species numberwas ofa difficultspecies task. although Previous species surveys composition had also varied SUCCeede grer tly.in Preliminary data on snakes diversity were recorded during the 1996 Maliau expeditio ; 9 species of snakes were collected, one of each species.However, species identification~ of the findings were not available. The possibility of discovering new speciesof reptiles in!