Checklist of vascular plants from Batu Caves , Selangor , Malaysia

The vascular plant flora of Batu Caves, a tower karst limestone formation, includes 269 species; 51 species (19%) are Peninsular Malaysian endemics and 80 species (30%) are calciphiles of which 56 (21%) are obligate calciphiles and 26 species are obligate calciphiles endemic to Peninsular Malaysia. Four taxa are endemic to Batu Caves itself. That Batu Caves harbours a sizeable fraction (21.4%) of Peninsular Malaysia’s limestone flora underlines the need for detailed checklists of each and every limestone hill to enable adequate planning of conservation programmes to support biodiversity. Because botanical collecting began in the 1890s, Batu Caves is important as the type locality of 24 plant species. Land-use pressures have over time eliminated the surrounding native vegetation, leaving the flora vulnerable to aggressive weedy and alien species. Although designated as a Public Recreation Area, its protection status needs to be enforced and the boundaries clearly marked.


Introduction
Batu Caves (3 o 14′ N, 101 o 41′ E), or Gua Batu (in Malay), is a limestone tower karst formation 11 km northeast of the capital Kuala Lumpur.It rises to 329 m tall and covers about 2.59 km 2 .This massif with its vertical cliffs and craggy summit is a dominant landscape feature.Batu Caves is most famous for the Sri Subramaniaswamy Temple that at the Thaipusam festival is visited by hundreds of thousands of devotees who climb the 277 steps up to the Temple Cave.Besides its cultural importance as a religious site, it is also important for its cave ecosystems and associated fauna (Moseley et al. 2012) and for its flora (Wycherley 1972).
Batu Caves has been exploited commercially for a very long time.At first by Chinese farmers who since the 1860s collected guano from the caves (Yussof 1997).Quarrying for limestone had already started by 1889 when H.N. Ridley first investigated the caves, flora and fauna.Although Batu Abstract: The vascular plant flora of Batu Caves, a tower karst limestone formation, includes 269 species; 51 species (19%) are Peninsular Malaysian endemics and 80 species (30%) are calciphiles of which 56 (21%) are obligate calciphiles and 26 species are obligate calciphiles endemic to Peninsular Malaysia.Four taxa are endemic to Batu Caves itself.That Batu Caves harbours a sizeable fraction (21.4%) of Peninsular Malaysia's limestone flora underlines the need for detailed checklists of each and every limestone hill to enable adequate planning of conservation programmes to support biodiversity.Because botanical collecting began in the 1890s, Batu Caves is important as the type locality of 24 plant species.Land-use pressures have over time eliminated the surrounding native vegetation, leaving the flora vulnerable to aggressive weedy and alien species.Although designated as a Public Recreation Area, its protection status needs to be enforced and the boundaries clearly marked.DOI: 10.15560/10.6.1420 Lists o f species many diverse literature sources as well as from herbarium specimens.This is necessary as a basis for drawing up conservation management programmes as well as for tracking the decline or loss of species and the invasion of aggressive alien or weedy species.

Materials and Methods
The checklist is based on a search of the literature (Henderson 1939, Wycherley 1972, and Chin 1977, 1979, 1983a, b are major works, but there are also many specialist articles on specific species) and herbaria that house major collections of specimens collected from Batu Caves, namely The Singapore Herbarium, Singapore Botanic Gardens, Singapore (SING); the Kepong Herbarium, Forest Research Institute Malaysia, Kepong, Selangor (KEP); and the University of Malaya Herbarium, Kuala Lumpur (KLU).The collections at KEP and SING are partially databased using BRAHMS (Botanical Research and Herbarium Management System), which greatly facilitated extraction of data.Extraction of data from KLU was done manually from accession books.In the case of dubious identifications, the herbarium specimen was checked and the name corrected.Only species recorded from the tower karst or limestone-derived soil at the base are included.Thus forest species that Ridley collected are not included in the checklist, nor are weeds that grow on wasteland around Batu Caves, nor exotic aliens that have invaded disturbed areas at the foot of Batu Caves.
The checklist includes family and species names, cites specimens, provides the endemic status, whether endemic in Peninsular Malaysia (E) or endemic in the phytogeographic zone that straddles the border of Peninsular Malaysia and Peninsular Thailand (ET); and status as a calciphile, i.e. whether it is an obligate calciphile restricted to growing on limestone (R) or whether it is a characteristic species most usually found on limestone (U).

Results
The checklist (Appendix 1) includes 5 lycophyte species, 27 ferns, 2 gymnosperms, 182 dicotyledons and 53 monocotyledons, in total 269 species.This represents 22% of 1,216 species recorded growing on limestone in Peninsular Malaysia (Chin 1977).The percentages of endemic and obligate and characteristic calciphiles (Table 1) are representative of the limestone flora as a whole.
Of the 56 species of obligate calciphiles (Appendix 1), 26 are endemic in Peninsular Malaysia and are therefore of highest conservation concern.Among these are: Batu Caves is also important because it is the type locality for 24 taxa, even though some have since been reduced to synonymy.

Discussion
Table 1 illustrates the fact that while the limestone flora is species rich (1,216 species), only a fraction are found on a single hill (21.4% of the species on Batu Caves) due in part to local endemism of the obligate calciphiles.This is illustrated by the Gesneriaceae.For the Peninsular limestone flora as a whole, Gesneriaceae is ranked fourth with 39 species but on Batu Caves it is represented by just seven species.Of these, only two grow on nonlimestone substrates and are widely distributed; the rest are obligate calciphiles, two are local endemics, while the remaining three are more widespread but none are found on every hill.In fact it is the exception for limestone species to be encountered on every or even most hills.This is especially true among the obligate calciphiles.For instance, eight species of balsam are obligate calciphiles but only Impatiens ridleyi grows on Batu Caves and one other hill (Gunung Senyum, Pahang).The implications for conservation are two-fold.Firstly, to be able to make decisions on conservation management a detailed checklist for each hill is necessary and secondly, because each hill harbours only a fraction of the flora, a network of protected hills is required to capture the maximum biodiversity of the limestone flora.
Among the 267 species recorded from Batu Caves, 16 taxa (6%) are of conservation importance, either because they are local endemics that are restricted to just Batu Caves (4 species) or within 15 km of Batu Caves (3 restricted to limestone and 4 on both limestone and nonlimestone substrates) and 6 are widespread elsewhere but in Peninsular Malaysia are known only from Batu Caves.
Because Ridley was collecting when the flora of Peninsular Malaysia was just beginning to be known, many new species were described from Batu Caves (Table 2).From the scientific point of view, Batu Caves is important as a living museum where scientists are able to obtain living material of the authentic specimens from the type locality, for example, for DNA analysis, breeding and other investigations.
Although the Batu Caves tower karst formation has remained largely intact in spite of quarrying activity, the surrounding area has completely changed from pristine forest when Kelsall and Ridley made their collections, to the establishment of plantations that in turn were replaced by residential and industrial buildings and expanding infrastructure associated with the Sri Subramaniaswamy Temple.While the summit and flanks are largely undisturbed, the habitats around the base and associated with the Temple Cave are under severe pressure.This puts at risk populations of sensitive species that require moist shaded conditions, such as Argostemma inaequilaterum, which used to grow at the cliff base near the Art Gallery Caves; Impatiens ridleyi that only grows around the mouth of the Temple Cave where water constantly drips down; and Epithema parvibracteatum and Monophyllaea hirticalyx that grow on the rock scree below the skylight at the back of the Temple Cave.The latter species has not been seen for some years.With the removal of tree cover, aggressive invasive species both native, e.g.species of Macaranga and Mallotus (Euphorbiaceae) and of alien origin, e.g., Piper aduncum L. and Chromolena odoratum (L.) R.M. King & H. Rob.form thickets that smother the native flora.Of particular concern is Chromolena that in Active conservation management is required to protect these habitats from disturbance that not only drastically changes the microclimate but allows the invasion of these aggressive alien species.To protect the limestone flora there is an urgent need to clearly fence off the Public Recreation Area to prevent further intrusions.

Conclusion
Batu Caves is one of the iconic tower karsts in Peninsular Malaysia not only for its dominance of the landscape, but also for its Temple Cave that attracts hundreds of thousands of devotees.Scientifically it is important for its biodiverse flora, fauna and for its caves.Its flora is important in being species rich, including a high proportion of endemic and obligate and characteristic calciphiles, including taxa that are known only from Batu Caves, besides its historic importance as a type locality.
In view of the pressure on land from its proximity to the capital, Kuala Lumpur, there is an urgent need to enforce its legal protection status, to make clear the boundary of the Public Recreation Area, and to provide a buffer zone, preferably of tree cover, to protect the sensitive habitats at the foot of the cliffs and to provide a barrier to fire.

Acknowledgements:
This study was carried out as part of the Flora of Peninsular Malaysia Project funded by the Ministry of Science, Technology and Innovation through the National Council for Scientific Research and Development under Project No. 01-04-01-000 Khas 2 entitled "Safeguarding the Forest Plant Diversity of Peninsular Malaysia" and the 10 th Malaysia Plan Development Project entitled "Dokumentasi dan Inventori Flora Malaysia".Curators of the Kepong (KEP) and Singapore (SING) Herbaria are thanked for access to their BRAHMS databases and to the University of Malaya Herbarium (KLU) for access to accession books, and to all three herbarium for permission to examine specimens in their care.
• 4 local endemic species or varieties that are obligate calciphiles and are only known from Batu Caves-

ORIGINAL NAME CURRENT NAME IF REDUCED TO SYNONOMY
a fire risk.Recently human activity resulted in vegetation fires on one face of the tower karst.