Batu Caves hill is typical of karst hills in Peninsular Malaysia due to its small size and high biodiversity. It harbours 366 vascular plant species that represent about 25% of the Peninsula’s limestone flora. Five species are endemic to Batu Caves and 23 are threatened species. This high biodiversity is the result of many microhabitats, each with their own assemblages of species. Threats are especially severe as the area of Batu Caves is surrounded by urbanisation that encroaches to the foot of cliffs, is vulnerable to fire, habitat disturbance and, formerly, by quarrying. Assigning a Conservation Importance Score (CIS) to all species is quantitative and accurate, can be implemented rapidly and produces reproducible results. Species with highest CIS are native species of primary vegetation, restricted to limestone substrates, endangered conservation status and, in this case, endemic to Batu Caves. It allows not only species, but microhabitats, sites within a hill and different hills to be compared. By identifying and surveying all microhabitats and focusing on locating endemic and threatened species, maximum biodiversity can be captured. Of the 16 microhabitats identified, the most threatened were the buffer zone, lower levels of steep earth-covered slopes and cave entrances. Application of this method provides a scientific basis for balancing the need to protect microhabitats and sites with the highest CIS, with their multiple uses by various stakeholders, which, at Batu Caves, include the activities of cave temples and eco-recreation. It also provides a scientific quantitative method to compare hills to ensure that those hills with highest CIS are not released for mining.

The need to exploit limestone products for national development impacts on the conservation of rare and endangered limestone species. To minimise this impact it is necessary to identify which of the 570 limestone outcrops have high conservation importance and whether they have narrowly endemic and/or endangered limestone species. In the absence of detailed checklists for each outcrop, the Gesneriaceae is selected as being biodiverse on limestone, being well collected and outstanding in the number of endemic species and/or species restricted to limestone for mapping. Of the 210 species in the 25 genera of Gesneriaceae in Peninsular Malaysia, 42 species belonging to the genera Damrongia Kerr ex Craib, Emarhendia Kiew, A.Weber & B.L.Burtt, Epithema Blume, Microchirita (C.B.Clarke) Yin Z.Wang, Monophyllaea R.Br., Ornithoboea Parish ex C.B.Clarke, Paraboea (C.B.Clarke) Ridl., Senyumia Kiew, A.Weber & B.L.Burtt and Spelaeanthus Kiew, A.Weber & B.L.Burtt grow on limestone hills. Of these 42 species, 28 are endemic and 16 are restricted to a single or adjacent hills. Mapping their distribution shows that in common with other families there are three distinct phytogeographical provinces (the Northern Province, Perak Province and the Asian Intrusion) but that the narrowly endemic species do not cluster on particular hills, nor does their distribution coincide with those of other narrowly endemic species in other families. This illustrates that a network comprising a large number of hills, not only those within the three provinces but also all those harbouring narrowly endemic species that are at risk of extinction if not conserved, is necessary to maximise conservation of the biodiversity of the limestone flora.

A new species, Microchiritahairulii Rafidah (Gesneriaceae) from limestone hills in Perlis, Peninsular Malaysia, is described and illustrated. Diagnostic characters, description, detailed illustrations, geographical distribution, regional provisional conservation status assessment (Endangered) and ecological observations of the new taxon, as well as an updated key to Microchirita species in Peninsular Malaysia, are provided.

No abstract