Diversity and Biomass of Terrestrial Small Mammals at a Malaysian Primary Rainforest (Segari Melintang Forest Reserve, Peninsular Malaysia)
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THE JOURNAL OF TROPICAL LIFE SCIENCE OPEN ACCESS Freely available online VOL. 5, NO. 1, pp. 35-44, January, 2015 Diversity and Biomass of Terrestrial Small Mammals at A Malaysian Primary Rainforest (Segari Melintang Forest Reserve, Peninsular Malaysia) Nadine Brigitte Ruppert1*, Asyraf Mansor1, Shahrual MS Anuar1 1School of Biological Sciences, Universiti Sains Malaysia ABSTRACT Despite their importance for the rain forest ecosystem, it is still not much known about the community composition of small frugivorous mammals in West-Malaysian forests. Therefore, we conducted a mark and recap- ture study in four 100 m x 100 m sized plots in a lowland Dipterocarp forest of Peninsular Malaysia for 4000 trap nights. Plots hosted either Dipterocarp forest or alluvial freshwater swamp vegetation. We assumed that small mammal assemblages varied between these two vegetation types. In total 249 different individuals of 14 species (9 genera) were caught, comprising rodents and treeshrews. The most abundant species was the common treeshrew (Tupaia glis, 25.8 individuals ha-1). In second and third place were the plantain squirrel (Callosciurus notatus, 10.25 individuals ha-1) and the grey tree rat (Lenothrix canus, 10.0 individuals ha-1), respectively. These three species accounted for 77.8% of the total small mammal’s biomass per hectare. Sex-ratio of treeshrews and squirrel species was found at 1:1, whereas Muridae showed male-biased sex ratios. Shannon-diversity indices (H’) of all trapping plots ranged at a mediocre level. Plot comparison (Bray-Curtis indices) showed that plots with similar vegetation types were not more similar in their small mammals community structure. Other factors, such as dis- tance to the forest edge and joining oil palm plantations seemed to influence species abundances. Small mammals belong to the less studied species in local rain forests, thus studying their ecology is vital to act towards general conservational issues. Keywords: mark and recapture study, nonflying mammals, small mammal abundance INTRODUCTION gion include squirrels, treeshrews, rats, mice, and civets The tropical forests of the Malay Peninsula host [18]. This might be due to their mostly cryptic 205 known mammal species of 32 families (11 orders) appearance and behaviour. Many of them are quite [1]. Amongst them is the guild of small (weight less small, night active or forage high up in the canopy, than 1 kg), non-flying, terrestrial, frugivorous mam- hide in trees and burrows, or are rather trap shy. mals. They consist of various taxonomic groups and For this study we put our focus on frugivorous represent a vital component of this ecosystem. For ex- ground dwellers and tree climbers up to medium forest ample, they act as pollinators [2-4], fruit predators and levels (app. 5 m above ground). However, a wider seed dispersers [5-9] or valuable energy source when range of small mammals, i.e. several squirrel or Muri- becoming a prey for larger carnivores [10]. dae species, are only found higher up in the canopy Although, small mammals occur in complex com- [19]. munities with very high species richness and consider- The most abundant group of small non-flying able impact on the Malaysian rainforest ecosystem, mammals comprises rats and mice (order Rodentia, they have not received much public or conservational family Muridae) that are mostly night active and very attention, yet [11]. Especially the small mammals of diverse. They can be found on the ground where they the Peninsular are only little addressed in literature forage and rest in burrows, at medium forest levels, [12-17]. In fact, the least known mammals in the re- where they climb trees and nest in tree holes, as well as high up in the canopy. It is still very little known about *Corresponding author: this highly diverse family in South-East Asian primary Nadine Brigitte Ruppert School of Biological Sciences, Universiti Sains Malaysia forest systems, and neither their taxonomy nor the Email: [email protected] ecology and behaviour of most species have been stud- ied in detail. JTLS | J. Trop. Life. Science 35 Volume 5 | Number 1 | January | 2015 Nadine Ruppert et al., 2015 Treeshrews (order Scandentia, family Tupaiidae) The dominant vegetation types are lowland Diptero- belong to another important group of small mammals carp forest and freshwater alluvial swamp forests. The at the study site (here Tupaia glis). They have basically maximum height of the closed canopy is about 40 m diversified on the ground. Also some local squirrels [20]. (family Sciruidae), e.g. Low’s squirrel (Sundasciurus The climate of the study area is characterized by lowii), the Shrew-faced Ground squirrel (Rhinoscuirus the northeast monsoon with highest precipitation from laticaudatus) or the Plantain squirrel (Callosciurus no- October to December (209 mm to 251 mm). A short tatus) predominately use lower forest strata to forage dry season typically lasts from June to July (84 mm to during the day (pers. obs.). 90 mm). Annual average rainfall in the study area is For this study, a mark and recapture programme of 1,881 mm (1911-1975). The annual average tempera- small mammals (<250 g) was conducted at a lowland ture is 26.8°C (1961-1990) with minimum and maxi- rainforest reserve at the West coast of Peninsular mum annual averages of 22.6°C and 31.6°C respec- Malaysia. The study was aimed to identifying the small tively (1931-1975) (weather station Sitiawan 4° 22’ N mammal species at the study site. General abundances, 100° 70’ E, 7 m above sea level). biomasses, species-specific sex ratios, and diversity in- dices were addressed. The study site hosted two major Trapping plots vegetation types, i.e. lowland Dipterocarp forest and Four 1 ha-sized (100 m x 100 m) trapping plots temporal waterlogged alluvial freshwater swamp vege- were termed A, B, C and D and plot centres were lo- tation [20], mainly occupied by e.g. rattans, Salacca cated at least 150 m apart from each other. All plots spp. and Elaidoxa conferta. It was assumed that forest lied near to the forest edge (0-50 m) (Figure 1) and areas with a similar vegetation type would also host a were equally affected by human influences. similar small mammal community composition, i.e. Plot A was located at the very forest edge and that some species might prefer either one habitat. dominated by Dipterocarps and firm, undrained soils. It was directly flanked by oil palm plantations from MATERIALS AND METHODS one side, a small tar road that separated the forest from Study Site plantation from the second site, and the other two Trapping was conducted at a primary forest site sides were surrounded by primary forest vegetation. within the Virgin Jungle Reserve (VJR) of the Segari Plot B and C were located in a freshwater alluvial Melintang Forest Reserve (SMFR, compartments 62 swamp forest with a high proportion of rattans, and 63 1A) in Manjung District, Perak, Peninsular Salacca spp. (both Calamoideae) and Elaiadoxa con- Malaysia (4°18' N, 100°34' E) (Figure 1). ferta that dominated the vegetation. The soils of major The whole SMFR has a size of 2720 ha and con- parts of both plots were seasonally waterlogged (except tains 408 ha of strictly protected VJR. The rest is Per- for the dry season). Both plots centres (B and C) were manent Forest Reserve (PFR) with areas that were se- more than 60 m away from that road and oil palm lectively logged during the 1960’s. No obvious differ- plantation. Plot D was located at a slope. Its vegetation ences between the PFR and VJR in vegetation structure was dominated by Dipterocarps and Bertam (Eugeisso- and canopy density are visible as the vegetation in for- nia tristis) and it resembled Plot A in its main vegeta- merly logged areas has mainly recovered. The forest re- tion, except for a higher abundance of Bertam. Its plot serve is located near rural areas and prone to human centre was around 100 m away from the forest edge disturbance at medium levels, especially at its edges. and surrounded by forest from all sides. Occasional illegal logging of timber woods, collecting rattans and Bertam (Calamoideae), or poaching mam- Trapping programme mals (mainly Sus scrofa) and birds (pers. obs.) can be Trapping was conducted for forty days between observed. July and August 2010. In each plot 100 handmade To the west, the study site is bordered by planta- standard wire mesh traps (trap size H x W x D: 16 x tion land (oil palm Elaeis guineensis), to the south and 16 x 50 cm, mesh size: 10 x 10 mm) were set. They east by rural areas, and to the north by plantations and were placed along winding trapping trails that followed poultry farms. It is crossed by some small, seasonal vegetational gradients in order to be least invasive, and streams. were equally spaced throughout the 1 ha area of the The study site is flat to undulating with extending plot. Traps were placed on three different height levels elevation from sea level to app. 150 m above sea level. i.e. on the ground, at c. 0.5 m on lianas and fallen tree JTLS | J. Trop. Life. Science 36 Volume 5 | Number 1 | January | 2015 Diversity and Biomass of Terrestrial Small Mammals at a Malaysian Primary Rainforest Figure 1. Location of the Segari Melintang Forest Reserve, Perak, Peninsular Malaysia (above). Location of the four 100 m x 100 m study plots (A, B, C and D) within the SMFR near the village of Teluk Senangin (below). trunks and c. 3-5 m heights up in the trees with equal dissimilarities) were calculated using R (version 2.14.2).