Checklist of vascular plants of Klang Gates Quartz Ridge, Malaysia, a 14-km long quartz dyke

Abstract The Klang Gates Quartz Ridge (KGQR) is proposed for protection as National Heritage and as a UNESCO World Heritage Site because of its spectacular size, exceptional beauty and significant biodiversity. The checklist of vascular plants documents 314 species that comprise a unique combination that grows on lowland quartz and that is distinct from the surrounding lowland equatorial rain forest by the absence of orchids, palms, gingers and tree canopy families. The Rubiaceae, Gramineae, Moraceae, Apocynaceae, Melastomataceae and Polypodiaceae are the most speciose families. The summit vegetation at 200–400 m elevation is dominated by Baeckea frutescens (Myrtaceae) and Rhodoleia championii (Hamamelidaceae) and shows similarities to the plant community on rocky mountain peaks above 1500 m. About 11% of its species are endemic in Peninsular Malaysia and four are endemic to KGQR: Aleisanthia rupestris (Rubiaceae), Codonoboea primulina (Gesneriaceae), Spermacoce pilulifera (Rubiaceae), and Ilex praetermissa (Aquifoliaceae). All four are provisionally assessed as Critically Endangered. Two, Eulalia milsumi (Gramineae) and Sonerila prostrata (Melastomataceae), are endemic to KGQR and a few neighbouring smaller quartz dykes. They are assessed as Endangered. The KGQR is a fragile habitat and conservation management is urgently required to halt the spread of the aggressive alien grass, Pennisetum polystachion and to prevent further habitat degradation from visitors. Based on KGQR being a threatened habitat, its biodiverse flora, and endangered species, it qualifies as an Important Plant Area.


Introduction
The Klang Gates Quartz Ridge (KGQR), renamed Gombak Selangor Quartz Ridge (Mohd.-Zainuddin 2015), is a 14 km-long quartz dyke (3.12N, 101.42E to 3.15N, 101.48E) 12 km northeast of Kuala Lumpur in the state of Selangor, Malaysia. Rising to about 400 m, it dominates the skyline north of Kuala Lumpur and is believed to be the longest exposed quartz dyke in the world. Running from east to west, it is flanked to the north by the Hulu Gombak Forest Reserve Extensions and the Klang Gates Dam, a large reservoir covering 207 ha that supplies water to the capital, Kuala Lumpur. To the south, it is increasingly exposed to human disturbance.
Composed of pure quartz, the dyke was exposed as the surrounding granite material weathered away revealing sheer pale grey or white vertical cliffs rising above the surrounding vegetation. Though about 200 m wide at the base, in places the summit ridge is a knife edge only a metre or so wide with precipitous drops on either side. Jagged like a dragon's spine, it is dissected by vertical faults giving it the appearance of limestone karst, so it has been termed a pseudo-karst formation. It is pierced by three rivers that flow through narrow gullies. The pure quartz weathers to coarse sand that is very nutrient poor, has poor water retention, and has crumbled to form a steep base of colluvium with 30-35° and in places up to 60° slopes.
Adaptation to the extremely poor nutrient status and water retention has resulted in a distinctive flora with a unique assemblage of plants that includes several rare and/ or endemic species restricted to the KGQR. It is markedly different from the surrounding tropical lowland rain forest not only in species composition, but also in physiognomy (with sparse stunted trees), complexity (not multi-layered and without the epiphyte flora) and lower species diversity (Saw 2010).
Its striking topography and unique flora have long attracted botanists. The first botanical collections were made by H.N. Ridley, who made three visits in 1908Ridley, who made three visits in , 1916Ridley, who made three visits in and 1921 that mainly concentrated on the summit ridge flora. He wrote the first account of the flora (Ridley 1922a), describing ten new species. Henderson (1928) produced the first comprehensive listing of plants from the KGQR included in his checklist of the flowering plants of Kuala Lumpur. It was based on collections made by Forestry Department staff, in particular by Mohd Hashim in 1908, and by H.L. Hume, employed by the Federated Malay States Museum, in 1921, who discovered the new species, Hydnocarpus humei, that was named in his honour. Subsequently, the herbarium collection of the Federated Malay States Museum was loaned indefinitely to the Singapore Botanic Gardens Herbarium (Henderson 1928). Henderson's listing of 265 species provided the most complete inventory of the vegetation on the steep slopes that were still forested in those days. Unfortunately, Henderson did not cite specimens. Later significant collections were made by staff of the Forest Research Institute Malaysia, principally by E.J. Strugnell in 1927and C.F. Symington in 1933, 1935and 1939. After a long hiatus, Kiew (1978) described a new species, Ilex praetermissa, she had discovered and produced the third account of the flora (Kiew 1982) based on her collections made between 1977-1982 and included for the first time a checklist of ferns collected by B. Molesworth-Allen and A.G. Piggott, who recorded Syngramma dayi, a fern restricted to quartz habitats.

Effect of Human Activities on the Flora of KGQR
Being so close to the capital Kuala Lumpur, it has suffered disturbance from agricultural activities, urbanisation, visitor pressure, and the invasion of alien weeds. All these activities threaten the continued existence of its flora and species of conservation importance. On the Kuala Lumpur side, encroachment from housing and road building threatens. The north side is protected by the Hulu Gombak Forest Reserve Extensions and the Klang Gates Dam.
Agricultural activities were a particular problem in the 1970s and 1980s (Kiew 1982;Perumal 1992) when there was widespread clearing of sections of the steep base on the south side to plant bananas and pineapple. Clearing the land by burning the vegetation got out of control and the 5 m-tall Baeckea frutescens trees were burned to the ground together with thick festoons up to half a metre long of the old man's beard lichen, Usnea sp. Fortunately, B. frutescens regenerated from seed and suckers but after 30 years the old man's beard lichen has not re-established (Kiew pers. obs.). Rhodoleia championii ( Figure 1) survived the fires with only its leaves being scorched, but in contrast the sappy Fagraea auriculata was totally destroyed. Due to the nutrient-poor soil, these agricultural activities failed and the area was quickly invaded by weeds of which the most damaging was the grass Imperata cylindrica, a fire hazard because it becomes tinder-dry in dry weather and fuelled fires on the lower slopes.
The impact of urbanisation began with the building of a bungalow in 1883 on the top of the ridge above the gully through which the Klang River flows. Between 1893 and 1895 this gully was dammed to form a reservoir (Barlow 1995). By 1926, the bungalow had become derelict and today any sign of it has almost disappeared, although a few garden plants still persist with the patch of the native Eriachne pallescens grass indicating where the bungalow once stood (Kiew 1982). In the 1950s a quarry was established at the western end to utilise the quartz for glass making. It had only a very local impact and was discontinued due to lack of commercial viability. The expanding population of Kuala Lumpur required a greater water supply that resulted in enlargement of the Klang Gates Dam to its present size. This caused some local damage. Housing developments continue to creep ever closer to the KGQR. The major Kuala Lumpur-Karak Highway cuts through the western end. In 2016, a major highway development, the Eastern Klang Valley Expressway, threatened its integrity but due to public protest was re-routed away from the KGQR.
The KGQR's easy accessibility and proximity to Kuala Lumpur has long encouraged rock climbers and hikers who are rewarded by a panoramic view of the Kuala Lumpur skyline in one direction and the reservoir lake and virgin rain forest in the other ( Figure 2). Unfortunately, increasing visitor pressure has its negative effects including cutting down trees for camp fires (Perumal 1992). In the 1980s it was still possible to see quartz crystals 7-10 cm long, but these have long since been taken by visitors. Notable too is the disappearance from easily accessible places of Eurycoma longifolia, formerly a striking plant on the summit (Kiew 1982). Local Malays believe it to be a powerful aphrodisiac. The spider orchid, Renanthera sp., reported by Adams (1953) is also long gone. Both are the prey of opportunistic collecting by visitors. However, they may persist on inaccessible peaks. The natural open nature of the KGQR flora makes it vulnerable to invasion by weeds. Formally, it was an island surrounded by rain forest that acted as a buffer against weed dispersal. Now this has gone from the southern side, so the KGQR is open to invasion by any weed that can withstand harsh conditions for plant growth. The agricultural activities mentioned above led to a great increase in the number of weed species recorded from the KGQR (Kiew 1982). After the initial invasion by Imperata cylindrica, by the 1990s Wong et al. (2010) reported that the aggressive fern Dicranopteris linearis covered large areas, the composite Chromolaena odorata, the shrub Clidemia hirta, the secondary forest tree Cyrtophyllum fragrans and a variety of grasses were already established.

Legal Protection
In 1936, 130 ha of the KGQR were gazetted as the Klang Gates Wildlife Reserve to protect all wildlife and in particular the serow, Capricornis sumatraensis, a totally protected animal in Malaysia (Perumal 1992). Over the years, KGQR has been proposed to be designated as a National Nature Monument (in 1974 by the Malaysian Nature Society in the Blueprint for Conservation in Peninsular Malaysia) and to be included in the Selangor Heritage Park (Wong et al. 2010). The Hulu Gombak Forest Reserve Extensions were given enhanced protection when upgraded to Permanent Reserved Forest Status and from 2007 the KGQR lies within the Selangor State Park. In June 2015, the Selangor Town and Country Planning Department (JPBD) renamed the KGQR the Gombak Selangor Quartz Ridge and committed to protect it as National Heritage and to get it declared a UNESCO World Heritage Site on the grounds that it is a world-class geological phenomenon being the longest exposed quartz dyke in the world, as well as for its spectacular size, exceptional beauty, and its importance as a significant natural habitat for in situ conservation of biodiversity. It is currently on the Tentative List of World Heritage Sites.
In anticipation of the KGQR becoming a UNESCO World Heritage Site, this account aims to make available essential baseline data on the unique assemblage of plants that make up its flora by providing: • a complete checklist of vascular plant species • details of the endemic and rare species of conservation importance • a complete bibliography for the botany of the KGQR.

Materials and methods
Accessibility and proximity to Kuala Lumpur means that many botanists have from time to time collected plants there so its flora can be said to be well-collected. This has meant that it has been possible to build the checklist using herbarium specimen data from the herbaria at KEP, KLU and SING that hold the majority of KGQR collections.
Herbarium codes follow Index Herbariorum at http://sweetgum.nybg.org/ih. Herbarium specimens provide a permanent record and, should there be questions about a species' identity, they can be verified at any time in the future by reference to the specimen. An example of the importance of making herbarium specimens is illustrated by the case of Hoya mappigera, a species only described in 2011 but that had been collected from the KGQR in 1962 (Sinclair 10730) under the name Hoya campanulata.
The database software Botanical Research and Herbarium Management System (BRAHMS) in the National Herbarium of Malaysia (KEP) at the Forest Research Institute Malaysia, Selangor, Malaysia, enabled records to be extracted from its extensive holding. Not included are exotic weeds, invasive species or plants from the surrounding lowland rain forest.
For cases where species are recorded from KGQR in the literature but specimens were not cited, for instance Henderson (1928), Molesworth-Allen (1963) and Piggott (Kiew 1982), the literature source is cited in the checklist.
In the checklist, four species proved to be endemic to KGQR, namely Aleisanthia rupestris, Codonoboea primulina, Ilex praetermissa and Spermacoce pilulifera (Figure 3). Following the IUCN criteria and categories (2001), these four species are all provisionally assessed as Critically Endangered under criteria CR B2ab(iii,iv) on the grounds that they are endemic in Peninsular Malaysia, where they are restricted to one locality that although it lies within the Selangor State Park is threatened by habitat degradation from visitor pressure and from invasive species. A further two species, Eulalia milsumi and Sonerila prostrata, endemic to KGQR and a few nearby smaller quartz dykes in the Gombak Valley, are provisionally assessed as Critically Endangered under criteria  EN B2ab (iii, iv) on the grounds that they are endemic species, restricted to two to four quartz dykes that, although they lie within the Selangor State Park, are vulnerable to habitat degradation. Other species of conservation importance include Syngramma dayi, endemic in quartz habitats in Perak and Selangor, and a few species that are extremely rare: Hydnocarpus humei is known from one other collection from Larut, Perak; Hoya mappigera is known from one other collection from Lumut, Perak, and another from Thailand. Further, the specimen of Galearia fulva that Ridley described as G. lancifolia is strikingly different from the typical form in having extremely narrow leaves and may prove to be a distinct taxon.

Habitats
Without a doubt, it is the summit flora that is of greatest botanical interest for its unique combination of species. Baeckea frutescens and Rhodoleia championii are the dominant tree species, while shrubs include Austrobuxus nitidus and Vaccinium bancanum and several epiphytic species, for instance Fagraea auriculata, Ficus deltoidea var. angustifolia and Rhododendron longiflorum, that here grow directly on the quartz rocks. The ground layer is sparse with mats of the white moss Leucobryum aduncum covering the thin peat layer. The endemic grass Eulalia milsumi forms sparse tussocks in soil-filled cracks and crannies. Aleisanthia rupestris as its name suggests grows in crevices on the sheer cliff faces in full sun. In contrast, Ilex praetermissa grows in forest on steep slopes in partial shade where there is an accumulation of peat. The gorges that pierce the ridge present a completely different cool, humid, shaded environment where lush herbs, for instance Begonia sinuata, Codonoboea primulina and gingers, can thrive.

Comparison with other plant communities
Notable in the checklist is the absence or poor representation of trees typical of the canopy of lowland equatorial rain forest (Saw 2010), such as the Anacardiaceae, Burseraceae, Dipterocarpaceae, Guttiferae, Leguminosae, Myristicaceae, and Myrtaceae, and families like Orchidaceae, Palmae and Zingiberaceae. While it is obvious that the harsh exposed conditions and scanty soil act as a filter that excludes the majority of trees, shrubs and herbs that are typical of equatorial rain forest, it is notable that this lowland quartzite flora at 200-400 m elevation has much in common with the plant community of upper montane forest that grows above 1500 m on mountain peaks with peat that develops on weathered granitic soils (Reid 1951). In fact, Ridley (1922b) first drew attention to this phenomenon noting that KGQR included a "small but quite peculiar flora consisting of several endemic species with several only known from much higher altitudes in our mountains". Species that illustrate this striking disjunct altitudinal distribution include Austrobuxus nitidus, Baeckea frutescens, Dipteris conjugata, Oleandra neriiformis, Rhodoleia championii and Vaccinium bancanum. Further, Whitmore (1984) drew attention to a few of these species, Austrobuxus nitidus and Baeckea frutescens, that also grow in lowland heath forest that also has base-poor, often sandy soil topped by a peat layer. It might be expected that the quartzite flora would share similarities with the limestone flora that also grows on a rocky, free-draining substrate with poor soil development. However, comparison with the flora of Batu Caves with 269 species (Kiew 2014), a karst hill just 7 km from the KGQR, shows that in fact they share very little in common with just five species that grow in both localities, namely, Alstonia scholaris (a secondary forest species), Pogonanthera pulverulenta (an epiphyte that grows on trees, not on the rock substrate), Microsorum membranifolium (a lithophyte), and the figs, Ficus hispida and F. punctata. Even at the family level, the differences are very pronounced. At Batu Caves, Orchidaceae is the most speciose family with 23 species contrasting with just two orchid species on KGQR; while speciose families on KGQR, Rubiaceae (32 species), Gramineae (15 species), Melastomaceae (10 species), Polypodiaceae (10 species) and are represented by 13, 0, 1 and 2 species, respectively, on Batu Caves.

Changes in the flora
The repeated burning of a large section of the southern face has resulted in longterm detrimental consequences. The steep slope is still covered by secondary vegetation among which the aggressive fern Dicranopteris linearis smothers competing vegetation. Many of the trees recorded by Henderson (1928) have not been recollected for more than 50 years, though they might still persist on the undisturbed northern side. Sonerila prostrata and Spermacoce pilulifera have not been re-collected for more than 35 years.
Among the site endemic species, Ilex praetermissa populations are now found only on the northern side suggesting that they are unable to disperse and become established in secondary vegetation on the southern side. This species is critically endangered having an extremely small population size and, in addition, it is a dioecious species (Kiew 1983). Wong et al. (2010) counted only 20 Ilex plants on a 250 m transect.
The endemic grass, Eulalia milsumi, is also seriously threatened by disturbance. Although reasonably common in less disturbed habitats, Wong et al. (2010) discovered that its population is highly sensitive to disturbance by aggressive smothering by weeds like Dicranopteris linearis and that it was significantly less frequent in disturbed areas. In addition, recently it is particularly threatened by the large, tussock forming alien grass, Pennisetum polystachion, first reported from KGQR by Yao (2007), but is now widespread (Kiew 2009;Lim and Yao 2010).
Fortunately, Aleisanthia rupestris appears to be less influenced by disturbance (Wong et al. 2010) probably because it grows in such exacting conditions in full sun on vertical rock faces rooted in tiny cracks and crevices where even weeds are unable to gain a toe-hold.
The very small population of Codonoboea primulina of less than 150 individuals that grows in an extremely small area measuring about 50 m 2 (Kiew 1983), is most at risk from botanical collectors, even though there is no need for repeated collecting because it is already represented in most major herbaria in the world.

Conclusion
The proposal by the Selangor Town and Country Planning Department to protect the KGQR under the National Heritage Act 2005 (Act 645) status is long overdue. Globally, it is indeed unique for a combination of its great size, the tall exposed quartz dyke with its pseudo-karst morphology, and its unique assemblage of plant species that includes endemic and rare plants. It meets all three criteria for being designated an Important Plant Area (Anderson 2002). The quartz dyke is a fragile, threatened habitat vulnerable to visitor pressure and invasive plant species, it harbours a unique biodiverse flora quite unlike that of either lowland forest or the limestone hill flora and of its 314 species 11% are endemic to Peninsular Malaysia, among which four are provisionally assessed as Critically Endangered and two as Endangered. Management of the dyke not only needs to control visitor access (Mohd.-Zainuddin 2015) but also to manage the invasion of aggressive weed species, most notably the Dicranopteris linearis thickets and to weed out Pennisetum polystachion by hand before it irreversibly impacts on the native flora.