The diversity of small mammals in Pulau Perhentian Kecil, Terengganu, Malaysia

Islands are generally rich in marine biodiversity, but it also often hides unique and endemic terrestrial wildlife. The data of terrestrial wildlife in Malaysian islands are still severely lacking, notably from small islands. Hence, this study was conducted to survey and update the small mammal diversity (bats and non-volant small mammals) in Pulau Perhentian Kecil, a tourist destination famous for its magnificent, diverse marine life and white sandy beaches. Despite their touristic popularity, very few information is known about the faunal diversity in this island compare to their more massive neighbouring island, Pulau Perhentian Besar. The survey was carried out from 21 to 30 May 2014 recorded 56 individuals encompasses eight species of bats and five species of non-volant small mammals that were captured using mist nets, harp traps, and cage traps. The survey recorded 10 new species locality records for the island in which, five species were never recorded in Pulau Perhentian Besar. Hipposideros dyacorum, Tylonycteris fulvida, T. malayana, Rattus exulans, and Sundamys annandalei are also new distribution records for the Malaysian East Coast islands highlighting the importance of protecting island biodiversity. Nonetheless, it is hoped that this study not only highlights the species diversity on the island but also serve as a data for sustainable island tourism management planning, which will be crucial for the sustainable development and management of this ecologically sensitive area.


INTRODUCTION
Oceanic islands are well known to contain unique and endemic wildlife, contributing disproportionately 15-20 % of global terrestrial species which are available in one of the 3.5% planet's offshore landmass (Whittaker et al. 2017). Data on island mammals (bats and non-volant small mammals) in Malaysia are uncommon especially for small islands like Pulau Perhentian Kecil (Roslan et al. 2016;Jayaraj et al. 2019). Bats are found throughout the world continents except Antarctica with the highest diversity in equatorial territories (Taylor 2019). The wide distribution of bats coupled with the ability of flight allows bats to fill a plethora of niches making them the second most diverse group of mammals with 110 bat species documented in the Peninsular Malaysia alone (Lim et al. 2017). On top of that, bats are often the main native island mammals, providing seed dispersal and pollination services with their added mobility like flying foxes (Fujita & Turtle 1991).
In islands where there are other small mammals, they play ecological roles including consuming invertebrates and plant materials alongside becoming the prominent prey base for many predators (Pimsai et al. 2014). Malaysian non-volant small mammal diversity reports on islands remain limited by effort and funding simply because island trips are costly and climatic events are unpredictable. Past attempts have provided benchmarks but, due to irregular monitoring, species checklist on islands requires updating (Rahim et al. 2016). The data on the island mammals are not just important for planning conservation frameworks but also assessing introduced species and its estimated damage caused. One of the common introduced mammal culprits are rodents, causing harm to the natives to the point of extinction in islands all around the world such as New Zealand, French Polynesia, and Lord Howe Island, Australia (Towns et al. 2006;Harper & Bunbury 2015).
Threats facing island mammals including bats are mainly habitat loss and human disturbance (Jones et al. 2009). These threats are due to rapid growth of the tourism industry, which has put significant pressure on natural resources and land use in the Perhentian Islands (Aswani et al. 2018). In light of this lack of research on island mammal diversity in Malaysia, we have conducted a small mammal survey in Pulau Perhentian Kecil, the smaller neighbour and less studied island compared to Pulau Perhentian Besar in the state of Terengganu. This survey was aimed to determine the species diversity and update the mammal checklist on this island. Above all, it is hoped that this study not only highlights the species diversity on the island but also serve as data for sustainable island tourism management planning.

Site description
The Perhentian Islands (comprising of islands like Besar, Kecil, Serenggeh, Rawa, Tokong Kemudi, and Susu Dara) are situated 21km seaward from mainland Terengganu with accessibility from towns like Kuala Besut, Merang, and Kuala Nerus. Pulau Perhentian Kecil is approximately 524 hectares (Farhana 2018). These islands are also well-known and popular tourism destinations for their stunning coral reefs and beautiful sandy beaches.
A nine-day study was conducted in Pulau Perhentian Kecil, from 21 th till 30 th May 2014. Two sampling sites (site A and site B) located in the northern part of the island were chosen for this study, as shown in Figure 1. The southern part of the island was not chosen mainly due to time constraints and the possibly uncontrolled anthropogenic disturbance from Kampung Pasir Hantu, a village settlement located there.
Site A (North end: 5.937 0 N, 102.720 0 E, South end: 5.922 0 N, 102.720 0 E) is a combination of primary and secondary lowland forest while site B (North end: 5.922 0 N, 102.720 0 E, South end: 5.916 0 N, 102.718 0 E) is a secondary forested area similar to site A but sandwiched between Perhentian Kecil's main tourist beaches which are Long Beach and Coral Bay. Site B is more subjected to anthropogenic disturbances due to the vicinity to tourist beaches with a main trail frequently used by tourists to travel between the two beaches and small patches of agricultural land mainly for rubber. For both sampling sites, the vegetation gradually changes into typical coastal forest nearing the coast and beaches.

Small mammals sampling
Bats were captured using mist nets (mesh size: 4cm), and harp traps (4 bank, 2m 2 metal frame) which were placed at suitable bat flyways whereas collapsible cage traps baited with banana were used to capture non-volant small mammals. Both harp traps and mist nets were set up approximately 1m above ground and adjusted to change based on place of trapping. Mist nets and harp traps were checked from 19.00h to 21.00h, closed for the night and reopened and checked from 05.00h to 07.00h in the morning. Cage traps were set placed on a grid of 10m x 10m per trap and checked twice daily with rebait applied for missing or J TT rotten baits. Opportunistic sightings of small mammals in the sampling sites during netting and trapping were also made whenever possible. The total netting and trapping effort in this study summarized in Table 1. All standard body measurements (vernier caliper & metal ruler), weight (spring balance), gender and maturity state of each captured mammal taken for record and identification purposes based on the identification keys in species identification books (Francis 2008; Kingston et al. 2009). Selected individuals were euthanized and collected as voucher specimens by ethanol preservation (Permit number D-01052-16-19). These were deposited at Faculty of Earth Science, Universiti Malaysia Kelantan. Results are presented in the form of species composition at both sites with assessments of the most recent conservation status of these mammals (IUCN 2020; https://www.iucnredlist.org/) and Red List of Mammals for Peninsular Malaysia Version 2.0 (Perhilitan 2017). Lastly, we compared the results of this study with past studies in the Perhentian Islands (Kecil and Besar) plus other Malaysian east-coast islands including Pulau Bidong, Pulau Redang, Pulau Tenggol, and Pulau Tioman.

Statistical analysis
Shannon-Wiener diversity index (H') is used to calculate the species richness of Site A and Site B and compare the diversity of both sites. We used Mann-Whitney U test to compare the relative abundance of small mammals between sites. To enhance the statistical analyses conducted, we used rarefaction curve to visualize and calculate the species richness for a given number of individual samples. All statistical analyses was calculated using Paleontological Statistics (PAST) software.

RESULTS
A total of 56 individuals belonging to 13 species from six families were recorded in this survey, with site A (12 species, H'= 2.35) being more diverse than site B (seven species, H'= 1.7). Bats had the highest individual count and species diversity compared to non-volant small mammals. Pteropus hypomelanus was also observed

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to be abundant on the beaches of Pulau Perhentian Kecil during the sampling period. Civet droppings were also found in site B, but the species was unable to be determined during the sampling period. Both species is not included in our results due to insufficient capture details. Table 2 shows the species composition of small mammals at both sites in this survey. The total number of small mammals captured in Site A (n= 20) was lower than the total number of small mammals captured in Site B (n= 36  (Perhilitan 2017).
When the number of individual small mammals captured was standardized (n= 20), the rarefaction curve showed that the expected number of species found in Site A was higher than the expected number of species found in Site B (Figure 2). The rarefaction curve reinforces the relative abundance and species diversity results from Shannon-Weiner Index from both sites.

Family Tupaiidae Tupaia glis (Diard, 1820) (Common Treeshrew)
A total of 12 individuals were captured in the island with three at site A and nine at site B. The previous study conducted in the Perhentian Islands (Kecil and Besar) recorded a much higher capture at 21 and 56 respectively (Tamblyn et al. 2005). This species was observed throughout Pulau Perhentian Besar, including the island lowland forest, coastal forest and disturbed areas (Turner et al. 2003). It is common throughout Peninsular Malaysia, where individuals captured in Tasik Bera, Ulu Gombak, Pulau Pinang and Wang Kelian State Park (Jayaraj et al. 2013;William-Dee et al. 2019). According to Rahim et al. (2016), this species is not disturbed by tourists walking around the trails and beach and seen moving in their proximity. This diurnal species is commonly found in forests and nearby plantations as well as gardens. Their diet mainly consists of insects and the occasional sweet fruits (Francis 2019). Jayaraj et al. (2015) conducted a phylogenetic analysis on tree shrews of Peninsular Malaysia and described three genetically distinct forms of T. glis which coincides with the morphological analysis study from Yusoff et al. (2015). Tupaia glis from Perhentian Kecil is provisionally placed under T. glis morphotype two pending further taxonomic studies.

Cynopterus brachyotis (Muller, 1838) (Short-nosed Fruit Bat)
Two individuals were captured in which both were from Site A. This species can be traced back to two distinct lineages which are Sunda lineage (C. brachyotis) and Forest lineage (Cynopterus cf. brachyotis Forest) by using two regression models from Jayaraj et al. (2012a). The nominate for C. brachyotis (see Abdullah & Jayaraj 2006) has been identified to be the form previously described as C. cf. brachyotis Sunda (Campbell et al. 2004;Jayaraj et al. 2004 (Campbell et al. 2004). Cynopterus brachyotis occurs in orchards, plantations, and disturbed habitats while Cynopterus cf brachyotis Forest can be found in primary forest. Both C. brachyotis and C. cf brachyotis Forest has been known to intersect one another at forest fringes like recorded in Gunung Stong (Jayaraj et al. 2013) and even high up at Mount Penrisen (1,000m) (Jayaraj et al. 2006). The presence of C. cf brachyotis Forest could be attributed to

Eonycteris spelaea (Dobson, 1871) (Cave Nectar Bat)
One individual was captured only in Site A on the island. In comparison to past studies, Roslan et al. (2016)

Rhinolophus affinis Horsfield, 1823 (Intermediate Horseshoe Bat)
A total of 12 individuals were captured in the island with one at Site A and 11 at Site B. The previous study conducted in Pulau Perhentian Kecil, recorded one capture of this species (Tamblyn et al. 2005). As for Pulau Perhentian Besar, the number of R. affinis captured were two and seven individuals respectively (Tamblyn et al. 2005;Roslan et al. 2016). A common bat species in Malaysia, this insectivorous bat appears in most localities sampled in Peninsular Malaysia and it mainly roost in caves and forages in forests including dry forest, mature lowland forest and disturbed areas (Naharuddin et al. 2015;Ith et al. 2016;Jayaraj et al. 2016;Lim et al. 2017; Francis 2019).

Hipposideros cineraceus Blyth, 1853 (Ashy Roundleaf Bat)
This species is a new record for Pulau Perhentian Kecil. A total of nine individuals were captured in the island in which four were at site A while five were at site B; however, there were two recorded H. cineraceus individuals at Pulau Perhentian Besar (Roslan et al. 2016). This species roost in caves in small to moderately sized colonies, together with other Hipposideros bats (Kingston et al. 2009). This species has been found roosting inside culverts; thus, it is safe to assume H. cineraceus roost in a tunnel-like structure whether in the hilly forest or rocky terrain in Pulau Perhentian Kecil (Francis 2019).

Hipposideros dyacorum Thomas, 1902 (Dayak Roundleaf Bat)
This species is a new record for the Pulau Perhentian Kecil. One individual of this species was caught only in Site B on the island. On a slightly larger scale, there have been no records of H. dyacorum on Pulau Perhentian Besar either. This species is not commonly recorded in Peninsular Malaysia, with only eight recorded localities in the mainland such as Wang Kelian State Park (Jayaraj et al. 2013;Lim et al. 2017). This species roosts in a variety of roosting sites including caves, tree hollows and rock crevices. It mainly forages in the understory portion of the forest (Francis 2019).

Hipposideros larvatus (Horsfield, 1823) (Intermediate Roundleaf Bat)
This species is the third new record of Hipposiderids for Pulau Perhentian Kecil. A total of seven individuals were caught in both of the sampling sites on the island. Though usually brown, this species occasionally has bright orange fur due to the effects of cave bleaching (Kingston et al. 2009).

Family Vespertilionidae Tylonycteris fulvida (Blyth, 1859) (Mainland Lesser Bamboo Bat)
This species is a new record in the Perhentian Islands including Pulau Perhentian Besar. One individual was captured only in Site A on the island. Formerly known as Tylonycteris pachypus, taxonomic revalidation separates the name as mentioned earlier to Borneo and Sumatra, while T. fulvida restricted to mainland Southeast Asia (Tu et al. 2017). As its common name suggests, this species roosts in the internodes of small live bamboo stems (Francis 2019). There are bamboo plots in the west coast of Pulau Perhentian Kecil adjacent to the pathway between Coral Bay and Long Beach (Tamblyn et al. 2005). Although bamboo is the major roost for this species, it had also been observed to roost in small rock crevices and abandoned tree holes (Eguren & McBee 2014).

Tylonycteris malayana Chasen, 1940 (Mainland Greater Bamboo Bat)
This species is a new record for the Perhentian Islands including Pulau Perhentian Besar. One individual was captured only in Site A on the island. Like its smaller cousin, this species formerly called Tylonycteris robustula also undergo taxonomic revalidation (Tu et al. 2017). The distribution of T. malayana is in mainland Southeast Asia, while T. robustula confined to Borneo like in Kubah National Park and Sumatra (Anwarali et al. 2008;Tu et al. 2017). This species also roosts in bamboo internodes, entering through beetle created slits in which they prefer large dead stems (Francis 2019). The presence and abundance of bamboos usually signal a high possibility of this species and T. fulvida as in Gunung Stong, Gunung Reng and Gua Musang, Kelantan due to their roosting association with the bamboo plant (Jayaraj et al. 2012b. Both species regularly change bamboo roosting sites, usually lasting for a short time only (Medway & Marshall 1972).

Rattus exulans (Peale, 1848) (Pacific Rat)
One individual was caught only in Site A on the island. This species is a new confirmed record in the Perhentian Islands (Kecil and Besar). This species is a new confirmed record in Pulau Perhentian Kecil but may have already been recorded by Tamblyn et al. (2005) as the study listed three distinct Rattus spp. This species is the smallest among the Rattus sp. but tends to be larger on smaller islands (Francis 2019). Although this species is known to occur in anthropogenically modified habitats (cultivated lands, shrublands, and gardens), it can also J TT be found in forest edges, swamp forest, and limestone areas William-Dee et al. 2019).

Rattus tanezumi Temminck, 1844 (Asian House Rat)
A total of three individuals were captured (one was at Site A while two were at Site B). This species is a new confirmed record for Pulau Perhentian Kecil; however, a total of 15 R. tanezumi individuals were captured in Pulau Perhentian Besar (Rahim et al. 2016). This species has a generalized diet and is a major pest of plant crops in plantations. This species spends much time on the ground but can also climb well whether on trees or inside buildings (Francis 2019). Although R. tanezumi is expected to be confined to anthropogenically modified habitats, there were previous records of this species in rainforests and limestone areas of Borneo and Kelantan. This intrusion may be due to the encroachment of human settlements or plantations, even small ones into the vicinity of natural habitats (Wells et al. 2006;Jayaraj et al. 2016).

Rattus tiomanicus (Miller, 1900) (Malaysian Wood Rat)
A total of four individuals were recorded on the island in which two individuals were caught in both sites respectively. This species is a new confirmed record in Pulau Perhentian Kecil. However, three individuals of R. tiomanicus were captured in Pulau Perhentian Besar (Rahim et al. 2016). This species has a widespread distribution on Malaysian islands like Pulau Tenggol, Pulau Pangkor and its namesake, Pulau Tioman (Sen 1971;Pimsai et al. 2014;Jayaraj et al. 2019). This nocturnal species occurs in a wide range of habitats including coastal forests, grasslands, plantations, secondary forests but rarely inside houses. Just like other Rattus spp., the diet includes a wide range of animal and plant matter Francis 2019).

Sundamys annandalei Bonhote, 1903 (Annandale's Rat)
Previously assigned to the genus Rattus, this species has recently undergone a taxonomic revision, placing it in the genus Sundamys (Camacho-Sanchez et al. 2017). Two individuals were caught only in Site A on the island. This species is a new confirmed record in the Perhentian Islands (Kecil and Besar). This nocturnal species can be found in rubber plantations and secondary forest, mainly on the lower levels of the tree. Contrary to its appearance, this species is not known to be a significant pest like other rat species (Francis 2019).

DISCUSSION
Notably, the majority of the small mammals recorded in Pulau Perhentian Kecil were bats, conceivably due to the rockier terrain mainly in Site A and presence of an exposed sea cave in Tanjung Kerma near both sampling sites (Turner et al. 2003). While caves are the main roosting site for cave roosting bats, some of them also roost in rocks crevices and hollow trees like R. affinis, H. larvatus, and H. dyacorum (Ith et al. 2015;Francis 2019). As previously stated, Site A has a higher species diversity than Site B even though Site A has lower relative abundance (refer to     Shahidah 2014;Mohd-Hanif et al. 2015;Lim et al. 2016;Morni et al. 2016). Furthermore, the Pacific Rat, R. exulans is the most prosperous island colonizers among rodents in which this species is ubiquitous in East Coast Peninsular Malaysia and East Malaysia. Due to its smaller size in comparison with other larger rodent species, this species would often opportunistically seek competitionfree environments even at primary forests like in Royal Belum (Tamrin et al. 2010;Lim BL 2015). As for S. annandalei, its known distribution mainly restricted to West Coast Peninsular Malaysia, eastern Sumatra and Singapore. Although usually found in the mainland, S. annandalei can also be found in the islands of Padang and Rupat, Riau. Currently, it is still unclear on why S. annandalei has such a restrictive range compared to Sundamys muelleri which has an extensive range across southeastern Asia including on Sundaic islands as there are no evident ecological barriers for S. annandalei to expand its range (Pimsai et al. 2014;Camacho-Sanchez et al. 2017). Therefore, the capture of this species in Pulau Perhentian Kecil is quite surprising, possibly being the key to answer Sundamys annandalei ecological range puzzle. Further sampling in the future is needed to discern whether the two individuals captured in this study were stowaways or an established population of S. annandalei thrived on Pulau Perhentian Kecil.

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Overall, Pulau Perhentian Besar has a higher number of species (12 for bats and 13 for small non-volant small mammals) compared to Pulau Perhentian Kecil (10 for bats and seven for small non-volant small mammals) probably due to its larger size enabling support of a broader range of niches (Kisel & Barraclough 2010). Despite this, human economic activity may influence the translocation of species, particularly non-volant small mammals across these two islands (Helmus et al. 2014). In comparison with other Malaysian east coast islands, Pulau Tioman amassed the highest number of mammal species at 41 which is not surprising, considering the island is also the largest (13,360ha) and has extensive flora and fauna surveys conducted since 1899 . While Pulau Redang is bigger than both Perhentian Islands combined at 1909ha, the lower number of mammal species recorded in this island is probably due to undersampling efforts, hence this island requires an updated mammal species checklist. The same goes to Pulau Bidong and Pulau Tenggol which has no published small mammal diversity records.