Small vertebrates in CFS ecological corridor (D-PL1: Lojing - Sungai Brok - Sungai Betis Forest Reserves) Kelantan

. Small vertebrate surveys were carried out in the Sungai Brok and Sungai Betis Forest Reserves. The Central Forest Spine (CFS) initiative has recognised these forest reserves as part of Kelantan's important ecological corridors, known as D-PL1. The surveys were conducted from July to September 2019. This study aims to identify and update the checklist of small vertebrates in the selected forest reserves. One hectare plot was established in each forest reserve for this study. Traps were used to capture and document these vertebrates, including 100 collapsible cage traps, three harp traps, 10 mist nets, and 25 pitfall traps deployed at each sampling site. In addition, the surveys also carried out active searches and direct observations. Overall, this study recorded 83 species from 38 families of small vertebrates. With the total, small mammals comprise of 13 spp. from six families, birds (53 spp. from 24 families), and herpetofauna (17 spp. from eight families) were recorded during this study. Ten small mammal species are recorded as additional species for D-PL1. Birds and herpetofauna recorded 38 and eight additional species to the existing checklist of D-PL1, respectively. Based on the IUCN Red List of Threatened Species (Version 3.1), this study recorded three threatened species namely Great Argus ( Argusianus argus ), Great Slaty Woodpecker ( Mulleripicus pulverulentus ),


Introduction
Malaysia is a megadiverse country that inhabits at least 307 species of mammals, 785 birds, 567 amphibians, and 242 reptiles [3].They can be found in different kinds of habitats including primary and secondary forest reserves, mangrove forests, peat swamp forests, and forest plantations.Small vertebrates are animals that have backbones and weigh less than five kilograms as an adult, such as small mammals, birds and herpetofauna (amphibians and reptiles) [1,2].They play significant ecological roles as seed dispersers, pollinators, and insect population regulators [4,5,6].
However, forest fragmentation or habitat loss has posed a significant threat to Malaysia's biodiversity, especially small vertebrate populations [3].Hence, the Central Forest Spine (CFS) initiative was established to safeguard biodiversity by re-establishing connectivity between fragmented forests in Peninsular Malaysia [7].The establishment of ecological corridors will facilitate wildlife movements, gene flow, and the spread of seeds and pollen in order to reduce the risk of species extinction [8].A total of 39 ecological corridors, comprising 20 Primary Linkages (PL) and 19 Secondary Linkages (SL) have been identified across eight states, including Kelantan.
There are six ecological corridors in Kelantan, including D-PL1: Lojing-Sungai Brok-Sungai Betis Forest Reserves [7].Forest reserves in the ecological corridor linkage have been separated by agricultural areas and highway [7].To date, Lojing Forest Reserve (LFR) has recorded 12 small mammal species from six families, 61 bird species from 29 families, and 20 amphibian species from seven families [9,10,11].Sungai Brok Forest Reserve (SBRFR) has reported one small mammal species from one family and one amphibian species from one family [12,13].Sungai Betis Forest Reserve (SBEFR) has recorded two small mammal species from two families and two amphibian species from two families [13,14,15,16].Yet, there is still a lack of information on small vertebrates in the forest reserves, especially for SBRFR and SBEFR.
Therefore, the purpose of this study is to document and update the checklist of small vertebrates in the selected forest reserves.The information on small vertebrates is essential in developing conservation plan for the forest reserves in D-PL1.

Study Sites
This study was carried out at Sungai Brok Forest Reserves (04 ᵒ 40'26.5"N, 101 ᵒ 38'34.7"E) and Sungai Betis Forest Reserve (04 ᵒ 44'41.8"N, 101 ᵒ 39'23.5"E) (Figure 1).Both forest reserves consist of secondary lowland forests.In Sungai Brok FR, the study plot has hilly areas and a closed canopy cover with tall trees.Apart from that, the study plot was also located near a river with rock crevices.On the other hand, Sungai Betis FR has hilly areas with dense understorey vegetation.Most of the areas in the study plot have closed canopy cover with several gaps and openings.During the surveys, logging activities or land clearing were still taking place in the areas adjacent to the forest reserves.

Field Methods
The surveys were conducted from July to September 2019.A 1-ha plot (100 m x 100 m) was established in each forest reserve, and each plot was sampled twice.Ten transect lines of 100 m length with 10 m separations were prepared for each plot.For each plot, a total of 100 collapsible cage traps baited with oil palm fruit were deployed to capture non-volant small mammals.Three harp traps were used to catch insectivorous bats, while ten mist nets were used to catch frugivorous bats and birds.Twenty-five pitfall traps were used in each plot to capture herpetofauna.The traps were left open for five consecutive nights and checked twice daily, as early as 0630 and 2230.
Active searches were also carried out for two consecutive nights (minimum of two hours per night) during each sampling session.Direct observations were also conducted during the surveys.All captured individual morphological measurements were recorded in this study.The species identifications were based on descriptions in Kingston et al. [17] and Francis [18] for mammals, Robson [19] for birds, and Norhayati et al. [20], Das [21], and Norhayati [22] for herpetofauna.
The information on small vertebrates from previous and present studies was gathered to identify additional and threatened species at the forest reserves.The checklist of small vertebrates recorded during this study was produced.

Results and Discussion
Surveys at the two forest reserves have recorded a total of 83 species from 38 families of small vertebrates.These comprised 13 small mammal species from six families (Table 1), 53 bird species from 24 families (Table 2), and 17 herpetofauna species from eight families (Table 3).
According to the findings, SBEFR had the higher number of small mammal species compared to SBRFR, with 10 and nine species, respectively.This might be associated with dense understorey vegetation in the study plot, which usually provides favorable conditions for the occurrence of small mammals [23].The family Vespertilionidae is the most diverse group of small mammals recorded during the surveys, four species.This is due to the fact that it is the largest, most diverse, and most widespread family of bats, occurring on every continent except Antarctica [17,18].
Besides that, SBRFR recorded higher number of bird species than SBEFR, with 38 and 35 species, respectively.This might be due to the availability of various food sources from the fruiting trees, the abundance of insects, and aquatic animals from the nearby river.Birds often prefer to utilize various habitats and rely on the quality and productivity of those habitats in term of food supply, shelter, and breeding sites in order to maintain viable populations [24,25].The most dominant group of birds recorded in this study is family Pycnonotidae with a total of eight species.The presence of fruiting trees, such as fig trees, might have contributed to this finding, as Pycnonotidae prefer to feed on fruits.[19].
As for the herpetofauna, SBRFR reported the highest number, with 14 species, while SBEFR recorded three species.This finding might be related to the presence of freshwater habitat nearby the study plot.The nearby river provides suitable habitat for herpetofauna that depends on wetland environments and adjacent terrestrial habitats to carry out their life cycles, such as breeding and foraging for survival [26,27].The families Dicroglossidae and Ranidae are the most dominant groups of herpetofauna recorded in this study, both with four species.Dicroglossidae and Ranidae are terrestrial and aquatic species that can be found in various habitats [28,29].
Based on the compilation of previous and present studies of small vertebrates, a total of 154 species from 54 families of small vertebrates were recorded at the forest reserves in D-PL1 [9,10,11,12,13,14,15,16].Of these, there are 24 small mammal species from eight families, 99 bird species from 35 families and 31 herpetofauna species from 11 families.This study has successfully recorded 10 additional small mammal species, 38 additional bird species, and eight additional herpetofauna species for D-PL1.
Moreover, D-PL1 also recorded a total of three threatened bird species based on the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species (Version 3.1).The threatened species are Great Argus (Argusianus argus), Great Slaty Woodpecker (Mulleripicus pulverulentus), and Grey-cheeked Bulbul (Alophoixus tephrogenys) [30].

Conclusion
In conclusion, CFS ecological corridor D-PL1 is an essential habitat for numerous species of small vertebrates.Dense understorey vegetation, availability of food sources, and freshwater habitat might be among the factors that influence the occurrence of small vertebrates in forest reserves.The presence of additional species of small vertebrates in the surveys indicates that more species have not yet been discovered and documented in the corridor.Therefore, continuous monitoring that covers more areas of the forest reserves is needed in order to better understand the population dynamics of small vertebrates in the ecological corridor.Thus, this information is vital in supporting stakeholders in formulating management plans, especially for the forest mosaics in D-PL1 in order to provide secure habitat and pathways for the small vertebrates.

Fig. 1 .
Fig. 1.The location of the study sites.

Table 1 .
Checklist of small mammals recorded during this study.

Table 2 .
Checklist of birds recorded during this study.

Table 3 .
Checklist of herpetofauna recorded during this study.