The Palni Hills are an eastward spur of the Western Ghats with a
maximum East-West length of 65km., and a North-South width of 40km.
(area 2064sq.km.). These hills may be simply divided into four distinct
1. The foothills to 800m. consisting of thorn forest at the
lower range and then dry deciduous forest typical of Peninsular India.
There are also some very good stretches of evergreen riverine forest at
2. Sub-montane evergreen forest accompanied by shrub savannah to 1600m. although most has been converted to plantations.
3. From 1600m. to 2000m., the outer montane slopes characterised by grassland savannah and Shola.
undulating plateau interspersed with occasional peaks rising to c.
2,500m. (area 385sq. km, average altitude 2,200m.) largely consisting
of grasslands with bracken, interspersed with Sholas. The grassland
component is now largely dominated by forest plantation.
Ghats are themselves renowned as one of the World's great bio-diversity
hot-spots. This great chain of hills effectively operates as a string
of islands, each with their own distinctive eco-systems and varying
plant communities. Hotspots are identified by two main criteria; first
plant endemism and then degree of threat. Endemism is the main criteria
because endemic species are dependent on a single area for survival,
hence the island metaphor. The Palnis are one such "island".
Palnis differ greatly from much of the Western Ghats in that it lies in
the rain shadow of the backbone of the range, i.e. it receives only
light rainfall during the June-September S.W. monsoon.The bulk of the
rain falls on the Annamalais in the West in Kerala. The dense luxuriant
tropical rainforests of the Western lowlands are absent. Moist areas
though exist along the ravines and in the sheltered pockets of Shola
Here are often found endemic hotspots within a
hotspot, most notably Pambar Shola. These hotspots are also notable for
their relic populations such as Arenga wightii, Artocarpus hirsutus,
Mesua ferrea var. coramandeliana, Bentinckia condapanna and Pittosporum
tetraspermum, where only a few individuals of each species may be found.
Aerides crispa - becoming very scarce
Palnis have c. 15 endemic species, but share many more species that are
limited to just a few other neighbouring hills such as the Nilgiris and
the Annamalais. Fr. K.M. Matthew listed 1758 species as native in 1999,
(since then the list has grown). Of these Fr. Matthew rated 46 species
as vulnerable and 14 (amalgamated) as probably extinct locally.
threat status of many of these species has lessened due to our
cultivation and distribution since 1989. Of the 14 extincts, 6 have
been relocated and raised, 2 of them being reintroductions from the
neighbouring Nilgiris. Nevertheless we feel a fresh survey would
indicate a growing number of species that should be listed as
vulnerable due to the ever diminishing grassland habitat over the last
© 2006Vattakanal Conservation Trust. All rights reserved