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WESTERN GHATS: NEED FOR LOCATING,
STUDYING AND CONSERVING RELIC FORESTS
M D SUBASH CHANDRAN
G R RAO
T V RAMACHANDRA
Centre for Ecological Sciences, Indian Institute of Science, Bangalore
Lake 2010: Wetlands, Biodiveristy and
change
Lake 2010: Climate
Wetlands,
Biodiversity and Climate change
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WHAT ARE RELIC FORESTS?
Relics are taxa that occur in disjunct areas – intermediate link lost
by environmental or geological changes (Drude, 1890)
Termed palaeoendemics (Chevalier & Guenot, 1925)
Relic or ancient endemism (Herzog, 1926)
Most endemics of peninsular India: palaeoendemics in suitable
ecological niches (Subramaniam & Nayar, 1974)
Relicts/palaeoendemics of restricted distribution are museums
than active speciation centres (Stebbins, 1980)
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PERSISITENCE OF RELICS IN THE WESTERN GHATS
Western Ghats, ancient mountain ranges, have relics of
geological ages - that lasted through ages despite
natural catastrophes (volcanism climatic changes etc.)
as well as human made catastrophes.
Vegetational relics reflecting culture are many such as
sacred groves enmeshed in a mosaic secondary
forests; including sacred sholas in between
grasslands
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Earlier studies in central Western Ghats show numerous forests
of relictual nature
A number of sacred groves (including kans) are relics of past vegetation
(Chandran & Gadgil, 1993; 1998; Chandran, 1997;1998).
Myristica swamps as having high endemism; as relics having Gondwana
lineage (Chandran & Mesta, 2001)
Discovery of Critically endangered Syzygium travancoricum & Madhuca
bourdillonii in forest relics of U. Kannada (Chandran et al., 2008)
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Fish endemism related to tree endemism in catchment area of
streams in Sharavathi basin (Sreekantha et al., 2007)
Schistura sharavatiensis
Schistura nagodiensis
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http://pubs.usgs.gov/gip/dynamic/historical.htm
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MESOZOIC EVENTS
FLORA
MID-JURASSIC (167 Ma): East
Gondwana elements shared by alldomination by pteridophytes &
Gondwana (Antarctica,
gymnosperms
Madagascar, India & Australia)
separate from S. America-Africa
Magnoloid fossils from Northern Brazil
show flowering plants developed and
MESOZOIC: CRETACEOUS
diversified
• < 130 Ma:
Ectomycorrhizal dipterocarp ancestor in
Madgascar
• 125-130 Ma: India-MadagascarSeychelles separate from
Independent evolution of flora & fauna –
Gondwanan elements reach Indian
Gondwana
landmass through Africa - through land
• 88-90 Ma: Madagascar separates
bridges
•
•
from India-Seychelles
90-80 Ma: Africa separates from
S. America-Antarctica-Australia
80 Ma: Australia separates from
Antarctica
India-Seychelles share common elements –
continued movement of Gondwanan
elements
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FLOWERING PLANT EVOLUTION
• Flowering plants evolved in Cretaceous and highly diversified
120 Ma - the time of separation of India from Gondwana
• Most early taxa were Magnoloids and other early dicots
• Flowering plant pollen increase even in Laurasia
• Reasonably good fossil record by Early Tertiary
• India would carry early flowering plants from Gondwana
• Pre-volcanic fossils from infra-trappean sediments: parts of
Caryophyllaceae, Sapindaceae, Asteraceae, Euphorbiaceae,
Poaceae, Arecaceae etc.
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DECCAN VOLCANISM
65 Ma massive volcanism produced the largest continental lava deposit (Deccan Traps) in 200 Million
years. Outpourings of lava in 500,000 sq. km.
Deccan Trap : Source: National Geographic
Deccan volcanic province
http://www.largeigneousprovinces.org.07may.html
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K/T BOUNDARY EVENTS
(Cretaceous – Tertiary 65 Ma))
• Diversification of
angiosperms
• 66 -65 Ma: Seychelles
separates from India-Deccan
volcanism – 500,000 km²
covered with basaltic
outpourings – Deccan Traps
– Massive extinction in
water & land
• Increase in CO , SO NO
Global warming
• Large release of macronutrients
2
2,
2–
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K/T BOUNDARY EXTINCTIONS: ASTEROID IMPACT?
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FLOWERING PLANT EVOLUTION
• Flowering plants evolved in Cretaceous and highly diversified
120 Ma - the time of separation of India from Gondwana
• Most early taxa were Magnoloids and other early dicots
• Flowering plant pollen increase even in Laurasia
• Reasonably good fossil record by Early Tertiary
• India would carry early flowering plants from Gondwana
• Pre-volcanic fossils from infra-trappean sediments: parts of
Caryophyllaceae, Sapindaceae, Asteraceae, Euphorbiaceae,
Poaceae, Arecaceae etc.
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INTER-TRAPPEAN FOSSIL BEARING SEDIMENTS
Inter-trappean fossils:
Flacourtiaceae, Icacinaceae,
Euphorbiaceae etc.
NON-ENDEMIC CRATACEOUS
FOSSILS included:
Gondwanan dinosaurs, snakes,
amphibians, turtles,– of S.
America – connection through
Africa! -80Ma - latest
Laurasian lineage: certain
amphibians, lizards, eutherean
mammals & some plants –
transoceanic suggested
Fresh water ostracodes of high
endemism
http://geowebprinceton.edu/people/keller/deccan/deccan.html
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EQUATORIAL POSITION & EARLY TERTIARY RAINFORESTS
L. Paleocene – E. Eocene (55-50 Ma) :
Rain forests covered India –
including Kutch-Rajasthan. Pollen
similar to Myristica malabarica,
Dipterocarpus indicus, Pinanga
dicksonii, Arenga, Calamus,
Palaquium ellipticum, Garcinia spp.,
Calophyllum polyanthum, Cullinia
(Prasad et al; 2006-2009).
Collide with Asia; Rise of Himalayas (10
Ma); Dramatic climatic changes Decline of rain forests.
Asian monsoons 8 Ma; several Ice Ages
from 2.5Ma
http://www.emporia.edu/earthsci/student/wilson/gtpp.html
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DIPTEROCARPS SPREAD INTO ASIA FROM INDIA
•
Ancient family of Gondwana
lineage. Shares common ancestry
with Sarcolaenaceae of
Madagascar. Both families ectomycorrhizal. Exceptional family –
could not have crossed the sea or
non-forest barriers. Eocene
(55Ma) fossils show D. indicus
was widespread in India.
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Nasikabatrachus sahyadriensis : Seychelles links
Close relatives live in
Seychelles – from which
Indian separated 65 Ma.
Multiple lineages of frogs
survived Deccan volcanismlived for millions of years in
isolation and on drifting India
and many moved into Eurasia
after collision
Photo: Kalyan Varma
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REFUGIA IN S. WESTERN GHATS
S. W. Ghats have high degree of
endemism. Rainfall throughout
the year. Old lineages of plants
and frogs.
40,000 yrs ago – Late
Quaternary pollen deposit of
moist evergreen forest &
deciduous forest – when xeric
glacial climate prevailed in
Indian peninsula. Tertiary rain
forests perhaps survived as
riparian vegetation –
rejuvenated during Holocene as
modern extant flora (Farooqui
et al., 2010)
Photo: Manikantan
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HARMONY WITH NATURE
South & central Western Ghats escaped Basalt flow
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Madhuca1
RISING SOUTHERN ENDEMISM IN TREES -
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W GHATS
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Slide 19
Madhuca1
Erg_madhuca, 12/20/2010
GONDWANA ELEMENTS IN RELIC FORESTS
Dipterocarpus indicus in kan forests
Myristica swamp
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MYRISTICACEAE FOLLICULAR FRUITS, LARGE ARILLATE, RELIC
PROTO-DICOT SEEDS
Prototype of endotestal, mesotestal, exotestal & advanced types of seeds
Myristica malabarica - Endangered
Gymnacranthera canarica - Vulnerable
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ENDANGERED & CRITICALLY ENDANGERED IN RELIC FORESTS OF
CENTRAL W GHATS
Syzygium travancoricum
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MADHUCA BOURDILLONII IN CENTRAL WESTERN GHATS
(Critically Endangered – new report north of Palghat Gap - Chandran et al., 2008)
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Pinanga dicksonii – Tertiary pollen fossils (55 Ma)
Photo: Vijay Mohan Raj
Semecarpus kathalekanensis –
newly discovered in relic forest
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RELIC FOREST STUDY IN KATHALEKAN, UTTARA KANNADA
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LANDSCAPE ELEMENTS AND RELIC SPECIES
Myristica swamps, Dipterocarp
dominated evergreens,
Semecarpus kathalekaneniss
Syzygium travancoricum
Past shifting cultivation openings,
Present cultivation
Secondary forests in advance
stages of succession with return
of Dipterocarpus
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
DOMINATION BY GONDWANA ORIGIN FAMILIES
Dipterocarpaceae & Myristicaceae
Sapotaceae
Moraceae
Annonaceae
Elaeocarpaceae
Rubiaceae
Flacourtiaceae
Arecaceae
Celastraceae
Lauraceae
Oleaceae
Euphorbiaceae
Meliaceae
Ebenaceae
Sapindaceae
Anacardiaceae
Clusiaceae
Myrtaceae
Cornaceae
Myristicaceae
Dipterocarpaceae
SSF
0
50
100
150
200
250
NSSF
300
350
Tree no.
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•
•
Swamp-specific species under
threat due to insufficient
regeneration, encroachments,
diverting feeder streams for
irrigation
Dipterocarpus regenerates in
secondary forests in the absence
of fire – reasons: closeness of
parental stock and perhaps ectomycorrhiza
Basal area higher for streamswamp forests than other forests
Basal area comparison: Stream-Swamp forests (SSF)
vs. Non-Stream-Swamp Forests (NSSF)
6
5
Basal area (sq.m.)
•
4
SSF
3
NSSF
2
1
0
0
10
20
30
40
50
Quadrats
Chandran et al. 2010
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Carbon sequestration in swamp and non swamp forest
based on 90 quadrats of 9 grids
Swamp
Non swamp
Carbon sequestration
in t/ha
350
300
250
200
150
100
50
0
0
1
2
3
4
5
6
Grid number
7
8
9
Chandran et.al, 2010
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Our Gratitude to:
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Gururaja KV
Vishnu DM
Divakar Mesta
Boominathan A
Swethamala
Thulasi Raman
Sreekanth Naik
&
Ministry of Environment & Forests, Govt. of India
Indian Institute of Science
Karnataka Power Corporation
Forest Research & Training Institute, Govt. of Karnataka
Lake 2010: Wetlands, Biodiveristy and
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