Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 August 2022 | 14(8): 21651–21659
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7860.14.8.21651-21659
#7860 | Received 01 February 2022 | Final
received 19 July 2022 | Finally accepted 08 August 2022
A new population
record of the Critically Endangered Dipterocarpus
bourdillonii Brandis from the Anamalai
Tiger Reserve, India
Navendu Page 1,
Srinivasan Kasinathan 2, Kshama Bhat 3, G. Moorthi
4, T. Sundarraj 5,
Divya Mudappa
6 & T.R. Shankar Raman 7
1 Wildlife Institute of
India, Post Box No. 18, Chandrabani, Dehradun,
Uttarakhand 248001, India.
2–7 Nature Conservation
Foundation, 1311, 12th A Main, Vijayanagar 1st Stage, Mysuru, Karnataka 570017,
India.
1 navendu@wii.gov.in, 2
srini@ncf-india.org, 3 kshama@ncf-india.org, 4 moorthi@ncf-india.org,
5 sundarraj@ncf-india.org, 6 divya@ncf-india.org, 7 trsr@ncf-india.org
(corresponding author)
Editor: A.G. Pandurangan, Centre for Innovation in Science & Social
Action, Thiruvananthapuram, India. Date of publication: 26 August
2022 (online & print)
Citation:
Page, N., S. Kasinathan, K. Bhat, G. Moorthi, T. Sundarraj, D. Mudappa & T.R.S. Raman (2022).
A new population record of the Critically Endangered Dipterocarpus bourdillonii
Brandis from the Anamalai Tiger Reserve, India.
Journal of Threatened Taxa
14(8): 21651–21659.
https://doi.org/10.11609/jott.7860.14.8.21651-21659
Copyright: © Page et al. 2022. Creative Commons
Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: Fondation Franklinia
funded the study on conservation of threatened tree species in the Anamalai Hills and Rohini Nilekani Philanthropies and AMM Murugappa Chettiar Research
Centre supported the ongoing rainforest restoration project.
Competing interests: The authors
declare no competing interests.
Author details: Navendu Page is a scientist at the Wildlife Institute of India,
Dehradun. Srinivasan Kasinathan is a programme
coordinator at the Nature Conservation Foundation, Rainforest Research Station,
Valparai. Kshama Bhat
is a project coordinator at the Nature Conservation Foundation, Rainforest
Research Station, Valparai. G. Moorthi is a field technician
at the Nature Conservation Foundation, Rainforest Research Station, Valparai. T. Sundarraj is a field technician at the Nature
Conservation Foundation, Rainforest Research Station, Valparai.
Divya Mudappa is a
scientist at the Nature Conservation Foundation, Rainforest Research Station, Valparai. T.R.
Shankar Raman is a scientist at the Nature Conservation Foundation,
Rainforest Research Station, Valparai.
Author contributions: NP, SK, KB, GM, and
TS contributed to the field survey, data collection, and plant identification;
NP, SK, KB, TRSR, and DM jointly wrote the manuscript; DM, TRSR, SK, and KB conceptualised the study, secured funding, and contributed
to data curation and analysis.
Acknowledgements: We are grateful to
the Tamil Nadu Forest Department for research permits and the DFO, range
officers, and field staff of Manamboli Range for
their kind support. We thank Fondation Franklinia for funding the study on conservation of
threatened tree species in the Anamalai Hills and
Rohini Nilekani Philanthropies and AMM Murugappa Chettiar Research Centre for supporting our rainforest
restoration project. We thank Rajesh for assistance in the field and Pavithra
P. for help with data entry and compilation. We are grateful to Dr M.U. Sharief, head of office, BSI Coimbatore, for permitting us
to examine the specimens housed at MH Herbarium. We are also grateful to Dr K. Sankara Rao, herbarium in-charge, JCB, for permitting us to
deposit the voucher specimen at Herbarium JCB. We thank Drs N. Ayyappan and
V.B. Sreekumar for help in locating herbarium specimens and the Director and
team of FRI Herbarium for their help in providing images of the specimens. We
thank the reviewers and editors for constructive comments and Dr P. Jeganathan for the Tamil translation.
Abstract: Dipterocarpus bourdillonii, a Critically
Endangered tree species endemic to the Western Ghats, India, has hitherto been
reported mainly from the states of Kerala and Karnataka on the western slopes
of the mountain range. In Tamil Nadu, this species has been reported to occur
in two locations, but no population details have been documented and the
species has neither been listed in state floras nor in a recent compendium of
plant species. The present study documents the occurrence of a population of
the species, with at least 40 individuals, in the Anamalai
Tiger Reserve, Tamil Nadu, extends the known upper limit of its altitudinal
range to 733 m, and suggests further surveys and in situ conservation efforts.
Keywords: Anamalai
Hills, new distribution records, threatened plants, tropical rainforest,
Western Ghats.
introduction
The family Dipterocarpaceae includes a diverse group of tropical trees
that form dominant stands with some of the tallest standing tree species in
southern and southeastern Asian lowland tropical forests
(Appanah & Turnbull 1998; Ashton 2014). About 500
species in 17 genera of Dipterocarpaceae are known
around the world (Ashton 2003), of which five genera and 34 species, including
10 species in the type genus Dipterocarpus,
occur in India (Kundu 2008). Within India, Dipterocarpus
is distributed largely in lowland tropical forests of the north-east, the
Andaman & Nicobar Islands, and the south-west in the Western Ghats (Brandis
1906). The two species endemic to India, Dipterocarpus
indicus and D. bourdillonii, are both
restricted to the Western Ghats in southwestern India (Ramesh & Pascal
1997; Sreekumar et al. 2021).
D. bourdillonii has been assessed as a
Critically Endangered species by the IUCN Red List, with the global population
currently estimated at under 250 mature individuals and the largest known
subpopulation having less than 50 mature individuals (Deepu et al. 2021). The species is considered rare and has
so far been recorded only in scattered locations in the states of Kerala,
Karnataka, and Tamil Nadu, mainly on the western aspect of the Western Ghats
mountain range of India (Ramesh & Pascal 1997; Swarupanandan
et al. 2013; Sreekumar et al. 2021). It is reported to occur between 175 m and
600 m elevation in valleys along river courses (Jose et al. 2010; Puttaswamy et al. 2010). Within Tamil Nadu, D. bourdillonii occurrence has been reported from the Nilgiris and Megamalai hill
ranges (Ramesh & Pascal 1997) but nothing is known of its population and
associated species in the state. The present paper describes the occurrence of
a population of D. bourdillonii in the Anamalai Tiger Reserve, in the Tamil Nadu Western
Ghats.
Methods
The field survey was
carried out in the Anamalai Tiger Reserve (ATR),
Tamil Nadu, India (core zone: 958 km², 10.2160N, 76.8160E
– 10.5660N, 77.4160E) and the adjoining Valparai Plateau (220 km², 10.250N, 76.8660E
– 10.3660N, 76.9830E) in the Anamalai
Hills. The Valparai Plateau is a landscape dominated
by tea and coffee plantations with about 45 embedded rainforest fragments
ranging in area from 1 ha to over 300 ha (Muthuramkumar
et al. 2006; Mudappa & Raman 2007). As the focus
of this study was on threatened and endangered tree species found in the
mid-elevation tropical wet evergreen forest (tropical rainforest), the
fieldwork was confined to the western parts of the Reserve in Valparai, Manamboli, and Ulandy Ranges that contain most of the remaining
rainforests. The natural vegetation type falls mainly within the mid-elevation
(700–1,400 m) tropical wet evergreen forest of the Cullenia
exarillata – Mesua ferrea – Palaquium ellipticum type (Pascal 1988).
Between October 2020
and March 2022, 64 routes (29 sites) of 119.2 km total length were surveyed on
foot, spanning an elevation range of 580 m to 2,000 m in the rainforests of the
Anamalai Tiger Reserve and rainforest fragments in
the Valparai Plateau. After two D. bourdillonii trees were first observed along one of the
survey routes (11 km, walked on 30 January 2021) passing through the Ayyankulam area (Figure 1), the same area was subsequently
explored covering 0.81 km and 2.63 km (in March–April 2021) and in four trails
covering 3.31 km, 3.89 km, 3.0 km, and 4.1 km (in March 2022) recording
additional individuals. The total length of 28.74 km of trails were tracked
using a hand-held GPS (Garmin GPSMAP 64sc) and a checklist of all tree species
encountered along the trail (10 m on either side) was recorded. Plant species
were identified using available floras and field guides (Gamble & Fischer
1935; Pascal & Ramesh 1997; Page 2017) and based on the prior experience of
the authors with floristic and ecological research in the region (Muthuramkumar et al. 2006; Page et al. 2010; Osuri et al. 2017, 2019; Page & Shanker
2018, 2020). Species names were updated with reference to Plants of the World
Online, http://www.plantsoftheworldonline.org/ (POWO 2022).
At each of the 40 D.
bourdillonii trees found during the survey, the
following data centred on the tree were recorded: GPS coordinates and elevation
(using GPS unit), girth at breast height (GBH, at 1.3 m, or higher in case of
presence of buttresses), and tree height in metres measured with a rangefinder.
For measurement of additional variables, a subset of 23 D. bourdillonii trees was chosen after excluding
individuals that were less than about 30 m from previously-measured
conspecifics (to ensure independence of samples). For these 23 trees, the
following additional variables were measured keeping the focal tree as the
centre: slope (flat, gentle, moderate, steep),
canopy height (average height of trees in the immediate vicinity of
focal tree measured with a rangefinder in metres), and canopy cover (0%, 1–25%,
26–50%, 51–75%, 76–100%). The number of D. bourdillonii
seedlings (GBH <10 cm) and saplings (GBH 10–30 cm) in a 5 m radius
around each focal tree were also recorded. Observations on canopy shape,
buttresses, and phenophase (leafing, flowering,
fruiting) were noted. To record nearby tree species, point-centred quarter
(PCQ) plots were placed keeping focal trees at the centre and the nearest
individual tree >30 cm GBH in each of the four quarters was recorded, noting
the species and GBH. As these were trees in the immediate vicinity of the focal
trees, the frequency of different species was considered as indicative of
species association with D. bourdillonii.
Together, the survey trails enabled rapid coverage across wider areas to document
species occurrence, while the PCQs around focal trees helped document tree
species associated with D. bourdillonii.
Herbarium specimens
were examined at the Madras Herbarium (MH), Botanical Survey of India, at
Coimbatore, the Herbarium at the French Institute in Pondicherry (HIFP), the
Herbarium of the Kerala Forest Research Institute (Sreekumar et al. 2021), Peechi (KFRI), and at the Forest Research Institute,
Dehradun (DD). No specimens were available at the herbaria of the Botanical
Survey of India in Pune (BSI). From select trees observed during this study,
leaves, flowers, and maturing fruit were collected and photographed. These were
subsequently used for preparing herbarium specimens and deposited into
Herbarium JCB (Accession No.: JCB-1337) at the Centre for Ecological Sciences,
Indian Institute of Science, Bengaluru. A sample of 11 maturing fruits, fallen
on the ground in the vicinity of the trees, were individually measured for
weight using a digital Ohaus scale, and nut length (along main longitudinal
axis) and width (along two axes perpendicular to the longitudinal and to each
other) were measured using Vernier calipers. The
length and width of the two wings (enlarged sepals) of each of the fruits were
also measured using Vernier calipers (except in the
case of 1 fruit where 1 wing was broken, for which only width was measured and
not the length). Data from the study are available on Zenodo
(Page et al. 2022).
results
Tropical wet
evergreen forest areas between 580 m and 700 m elevation were present only
along six survey routes within the Manamboli Range in
ATR. These routes were in the Ayyankulam-Manamboli
area located along the Parayankadavu Ār (Ār = river) that flows into
the Parambikulam Reservoir in neighbouring Kerala
State (Figure 1). In 2021, 20 Dipterocarpus
bourdillonii trees were recorded along three
trails passing through two main locations along the Parayankadavu
Ār within ATR: 13 trees at Ayyankulam
(10.3810N, 76.9100E) and 7 trees at Ayyankulam
Parai (10.3860N, 76.9260E), the
latter about 2.4 km (1.8 km straight line distance) upstream from the former
location. In March 2022, another 20 trees were recorded, including two trees at
Ayyankulam Parai and 18
along three of the four additional trails surveyed along the same river: Ayyankulam Parai to Ayyankulam (left bank 9; right bank 8), and Manamboli Powerhouse to Ayyankulam
(left bank 1; right bank 0). D. bourdillonii
was not recorded in any of the other 59 trails surveyed in Anamalai
Tiger Reserve and Valparai Plateau.
The 40 D. bourdillonii trees were located at elevations between
627 m and 733 m and from the edge of the river to less than 100 m away from the
river banks. Two tall trees of the species, when first noted on 30 January 2021
along the river banks at Ayyankulam, were flowering
(Image 1). On two subsequent visits to the area, on 26 March 2021 (Ayyankulam) and 10 April 2021 (Ayyankulam
Parai), fruiting trees were observed with different
stages of fruit developments, a sample
of which were measured (Table 1) and photographed (Image 2). In March 2022,
subsequently, flowering trees and trees with immature fruits were also
observed.
The 40 D. bourdillonii trees recorded averaged 375.4 cm in girth
at breast height (range 90–622 cm) and 40.0 m in height (range 12–51.3 m, Table
1). In the PCQ plots centred on 23 individual D. bourdillonii
trees, a total of 37 tree species (92 individual trees >30 cm GBH) were
recorded, with the most frequently associated species being Paracroton
pendulus (13 individuals), Monoon
fragrans (8), Cullenia
exarillata (8), and Reinwardtiodendron
anamalaiense (5). In the vicinity of these D. bourdillonii trees, the average density of conspecific
seedlings was higher than that of saplings, which were in turn higher than the
density of D. bourdillonii trees (Table 1).
Twelve (52%) of 23 trees were noted to be emergent and the remainder were
canopy trees. Canopy shape was oval in 19/23 trees (remainder had spreading
canopies) and most (20/23) were located at spots with 75–100% canopy cover (2
trees in spots with 51–75% canopy cover, 1 at <25% cover). While four trees
were on flat terrain, the remainder were on gentle (7), moderate (6), or steep
(6) slopes. Nine trees had buttresses.
Taxonomy
Dipterocarpus bourdillonii Brandis in Hook., Ic. Pl. t. 25. 1895; Gamble, Fl. Madras 81(58). 1915; K.P. Janardh. in B.D. Sharma & Sanjappa,
Fl. India 3: 210. 1993; Subram., Fl. Thenmala Div. 27. 1995; Sasidh.,
Fl. Periyar Tiger Reserve 27. 1998; Anil Kumar et
al., Fl. Pathanamthitta 74. 2005; K.P. Janardh. & W. Arisdason in P.
Daniel, Fl. Kerala 1: 360. 2005.
Lofty, evergreen
trees, up to 51 m tall. Young parts covered with tawny stellate pubescence;
leaf buds obtuse, setose or woolly. Stipules large, amplexicaul, leaving an
annular scar. Leaves simple, alternate; petiole 4–5.5 cm long, swollen at the
apex, tomentose; lamina ovate or obovate, 18–45 x
12–25 cm, coriaceous, abaxially stellate hairy, adaxially sparsely
silky-villous, lateral vein 13–23 pairs, parallel, conspicuously raised
abaxially, base rounded, subcordate or cuneate,
margins undulate, ciliate, gradually or abruptly acuminate at apex. Flowers
bisexual, in axillary racemes, 10 cm long, and 3-5 flowered. Calyx segments 5,
2 rather long and linear, 3 shorter and triangular. Petals pinkish and white,
elliptic oblong, 3.5 cm long, densely pubescent outside, margin slightly
upcurved, obtuse at apex. Stamens (27–)30; anthers linear to lanceolate, ca.
0.9 cm long, sagittate at base, coherent; connective appendages as long as anthers;
filaments filiform, dilated at base. Ovary narrowly ovoid, sericeous,
3-loculed, with 2 ovules per locule; style finely
terete, with long silky hairs on lower half. Nut ca. 2 cm in diam., ellipsoid,
crowned by thickened, accrescent calyx lobes; calyx tube to 3.5 cm in diam., 5
winged; wing-like calyx segments 2, pinkish-red, linear-lanceolate, to 14 × 3
cm, leathery, 3-veined, rounded at apex (Table 1).
Flowering: January to March;
fruiting: March–June.
Herbarium specimens
examined: India, Tamil Nadu, Coimbatore District, Anamalai Tiger Reserve, Ayyankulam
(10.3800N & 76.9090E, 628 m), 30 January 2021, coll.
Srinivasan Kasinathan, Kshama
Bhat, G. Moorthi, T. Sundarraj,
T. R. Shankar Raman, and Navendu Page s.n. (Accession No.: JCB-1337).
Additional specimens
examined: India, Kerala, Travancore, 1894, Brandis 2403 (K!);
undated, 534 (MH!); Kollam District: Achankovil, 22
September 1977, N. Sasidharan 108 (KFRI!); 109
(KFRI!); Palakkad District, 550 m, 22 January 1980, P. Bhargavan
65660 (MH!); 350 m, 4 April 1983, P. Bhargavan
78309 (MH!); Ernakulam District: Anakulam,
14 March 1986, K.K.N. Nair 8079 (KFRI!); 7704 (KFRI!); Malayattoor,
February 1936, Forest Ranger 160 (FRI!, 9x); March 1936, Forest Ranger 767
(FRI!, 2x), May 1937, Forest Ranger 74608 (FRI!), 10 February 1898, T.F. Bourdillon 918 (FRI!); Tamil Nadu, Nilgiris District, 11 February 1984, B.R. Ramesh 5521
(HIFP!).
The present study
extends the known distribution of the Critically Endangered endemic Dipterocarpus bourdillonii
to the Anamalai Tiger Reserve in Tamil Nadu. It also
extends the known upper limit of the altitudinal range of the species to at
least 733 m, higher than the range of 200–400 m reported from Kerala (Swarupanandan et al. 2013), and 176–271 m reported from Kodagu
in Karnataka (Puttaswamy et al. 2010). The two MH
herbarium specimens examined were from trees located at 350 m and 550 m
elevation, while the BIOTIK website (Ramesh et al. 2010) reports the species
may occur in low elevation wet evergreen forests up to 600 m (BIOTIK 2021).
While D. bourdillonii has not been listed as
occurring in Tamil Nadu in state floras (Gamble & Fischer 1935; Nair &
Henry 1983; Matthew 1999; Narasimhan & Irwin 2021), there are two earlier
reports from Tamil Nadu, from Nadugani Ghat area in western Nilgiris
District (Ramesh & Pascal 1997) and a possible record in Megamalai Wildlife Sanctuary (V. Ravichandran, pers. comm.
July 2022), but no additional details are available. Although the Ayyankulam area within the Anamalai
Tiger Reserve falls within the zone of very high to excellent in terms of
habitat suitability for D. bourdillonii as
identified by species distribution modeling in an
earlier study (Swarupanandan et al. 2013), the
present report is the first to confirm the occurrence of D. bourdillonii in this area and is a new population
record for the state.
Discussion
The present report is
also significant as it confirms the presence of a significant population (at
least 40 mature trees) of D. bourdillonii in
the Anamalai Hills. As in earlier studies, D. bourdillonii trees were confined to areas close to
rivers on relatively flat to moderate slope. The trees were located mainly
along the river between Ayyankulam and Ayyankulam Parai, both within the
core area of the Anamalai Tiger Reserve, but the
occurrence of one individual further downstream along the Parayankadavu
Ār indicates there may be more individuals in the
intervening area. Given that the species has an estimated global population of
under 250 mature individuals, with less than 50 mature individuals in the
largest known sub-population (Deepu et al. 2021), the
Anamalai Hills population of least 40 mature
individuals gains significance as an important site for in situ conservation of
this Critically Endangered species.
Most (37) of the 40
trees observed were of large girth (>200 cm) and only few seedlings and
saplings were recorded in their vicinity. The species has been reported to have
intrinsically poor reproduction besides probably being affected by past selective
logging (Swarupanandan et al. 2013). Future studies
on population structure and regeneration of D. bourdillonii
are required to assess the regeneration status in the study area.
In other parts of its
distributional range, D. bourdillonii is
reported to occur with species such as Vateria
indica, Turpinia
malabarica, Dipterocarpus
indicus, Humboldtia brunonis,
and Nothopegia beddomei
(Pascal 1988; Puttaswamy et al. 2010; Swarupanandan et al. 2013). In the Anamalais,
while Paracroton pendulus
and Monoon fragrans
were most frequent near D. bourdillonii trees,
other lower elevation rainforest species such as Vateria
indica and Reinwardtiodendron
anamalaiense were also recorded in plots, besides
species such as Strombosia ceylanica and Anacolosa densiflora in the Ayyankulam
area. The expected natural vegetation types for this region include lower
elevation (<700 m) tropical wet evergreen forest of the Dipterocarpus
indicus – Dipterocarpus bourdillonii
– Strombosia ceylanica
type and medium elevation (700–1,400 m) tropical wet evergreen forest of the Cullenia exarillata
– Mesua ferrea
– Palaquium ellipticum
type (Pascal 1988). While Dipterocarpus
indicus was not recorded in the Ayyankulam Area
during the present survey, it is the fifth most common tree species in the Varagaliar area (c. 6 km straight line distance) within ATR
(Ayyappan & Parthasarathy 1999) and was also recorded there during the
present survey.
The newly-discovered Anamalai population also showed some morphological
peculiarities. The shape of the leaf apex of D. bourdillonii
is described in the literature as shortly acuminate (Brandis 1906). On mature
individuals in the Anamalai Hills, the leaves,
particularly those at the top of the canopy exhibited an abruptly acuminate
leaf apex, which may represent minor intra-specific variation.
Future surveys for D.
bourdillonii should cover a wider altitudinal
range (0–800 m) in evergreen forest areas along rivers. As the species can be
clearly identified from flowers and fruits, carrying out surveys between
January and April during the flowering and fruiting season is suggested. The
existing population in the Ayyankulam area should
continue to be protected, and in situ conservation efforts should focus on
areas within the known ranges of this Critically Endangered species.
Table 1. Dipterocarpus bourdillonii
focal tree characteristics: number of conspecific seedlings, saplings, and
trees, and fruit and seed measurements in the Anamalai
Tiger Reserve, Tamil Nadu. N = number of trees (tree measurements) and number
of fruits (fruit measurements).
Variable |
Mean |
Standard error |
Minimum |
Maximum |
N |
Tree measurements |
|
|
|
|
|
Girth at breast
height (cm) |
375.4 |
22.2 |
90 |
622 |
40 |
Tree height (m) |
40.0 |
1.3 |
12 |
51.3 |
39? |
Canopy height (m) |
40.0 |
1.0 |
30 |
48.8 |
23# |
Seedlings
(number/78.5 m²) |
0.9 |
0.3 |
0 |
6 |
23# |
Saplings
(number/78.5 m²) |
0.2 |
0.1 |
0 |
2 |
23# |
Trees (number/78.5
m²) |
0.1 |
0.1 |
0 |
1 |
23# |
Fruit measurements |
|
|
|
|
|
Mass of maturing
fruit (g) |
1.31 |
0.11 |
0.75 |
1.80 |
11 |
Nut length (cm) |
2.20 |
0.03 |
2.10 |
2.40 |
11 |
Nut width 1 (cm) |
1.28 |
0.02 |
1.15 |
1.40 |
11 |
Nut width 2 (cm) |
1.20 |
0.03 |
1.10 |
1.40 |
11 |
Longer wing length
(cm) |
9.56 |
0.30 |
8 |
11 |
10 |
Longer wing width
(cm) |
1.84 |
0.10 |
1.3 |
2.3 |
11 |
Shorter wing length
(cm) |
9.18 |
0.26 |
7.8 |
10.5 |
10 |
Shorter wing width
(cm) |
1.79 |
0.12 |
1 |
2.3 |
11 |
?—missing data from 1
tree | #—focal trees >30 m from conspecifics.
For
figure & images - - click here for full PDF
References
Appanah, S. & J.W.
Turnbull (Eds.) (1998). A Review of dipterocarps: taxonomy, ecology and
silviculture. Center for International
Forestry Research (CIFOR), Bogor, 220 pp.
Ashton, P.S. (2003). Dipterocarpaceae pp. 182–197. In: Kubitzki, K. & C. Bayer (eds.). Flowering plants ·
Dicotyledons: Malvales, Capparales
and non-betalain Caryophyllales.
Springer, Berlin, Heidelberg, x+418 pp.
Ashton, P.S. (2014). On the forests of
tropical Asia: lest the memory fade. Kew Publishing,
Royal Botanic Gardens, Kew, 670 pp.
Ayyappan, N. & N. Parthasarathy (1999). Biodiversity
inventory of trees in a large-scale permanent plot of tropical evergreen forest
at Varagalaiar, Anamalais,
Western Ghats, India. Biodiversity & Conservation 8(11): 1533–1554. https://doi.org/10.1023/A:1008940803073
BIOTIK (2021). Dipterocarpus bourdilloni – DIPTEROCARPACEAE.
BIOTIK http://www.biotik.org/india/species/d/diptbour/diptbour_en.html,
accessed 17 July 2021.
Brandis, D. (1906). Indian trees : An
account of trees, shrubs, woody climbers, bamboos, and palms indigenous or
commonly cultivated in the British Indian empire. Archibald Constable
and Co. Ltd., London, xxxii+767 pp.
Deepu, S., M.S. Sanil & V.B. Sreekumar (2021). Dipterocarpus bourdillonii. The IUCN Red List
of Threatened Species 2021: e.T33009A169589049. Accessed on 08 August 2022. https://doi.org/10.2305/IUCN.UK.2021-2.RLTS.T33009A169589049.en
Gamble, J.S. & C.E.C. Fischer (1935). Flora of the
Presidency of Madras: Parts I to XI. Secretary of State
for India, London, lxiv+2017 pp.
Jose, P.A., K. Swarupanandan
& R.C. Pandalai (2010). Restoration of Dipterocarpus bourdillonii
and Humboldtia bourdillonii,
two critically endangered endemic trees of the Western Ghats. Evergreen
(No.65/66): 1–2.
Kundu, S. (2008). A synopsis of Dipterocarpaceae in Indian subcontinent: Its distribution
and endemism. Acta Botanica Hungarica 50(1–2):
125–142. https://doi.org/10.1556/abot.50.2008.1-2.9
Matthew, K.M. (1999). The Flora of the Palni Hills, South India. Rapinat
Herbarium, St. Joseph’s College, Tiruchirapalli.
Mudappa, D. & T.R.S.
Raman (2007). Rainforest restoration and wildlife conservation on
private lands in the Western Ghats pp. 210–240. In: Shahabuddin,
G. & M. Rangarajan (eds.). Making Conservation
Work. Permanent Black, Ranikhet, 298 pp.
Muthuramkumar, S., N. Ayyappan, N.
Parthasarathy, D. Mudappa, T.R.S. Raman, M.A. Selwyn
& L.A. Pragasan (2006). Plant community
structure in tropical rain forest fragments of the Western Ghats, India. Biotropica 38(2): 143–160. https://doi.org/10.1111/j.1744-7429.2006.00118.x
Nair, N.C. & A.N. Henry (1983). Flora of Tamil Nadu,
India, Vol. 1. Botanical Survey of India, Coimbatore,
xxii+186 pp.
Narasimhan, D. & S.J. Irwin (2021). Flowering plants of
Tamil Nadu: a compendium. Care Earth Trust, Chennai, 1112 pp.
Osuri, A.M., D.
Chakravarthy, D. Mudappa, T.R.S. Raman, N. Ayyappan,
S. Muthuramkumar & N. Parthasarathy (2017). Successional status,
seed dispersal mode and overstorey species influence
tree regeneration in tropical rain-forest fragments in Western Ghats, India. Journal
of Tropical Ecology 33(4): 270–284. https://doi.org/10.1017/S0266467417000219
Osuri, A.M., S. Kasinathan, M.K. Siddhartha, D. Mudappa
& T.R.S. Raman (2019). Effects of restoration on tree communities and
carbon storage in rainforest fragments of the Western Ghats, India. Ecosphere
10(9): e02860. https://doi.org/10.1002/ecs2.2860
Page, N. (2017). Endemic woody plants
of the Western Ghats: A photographic guide. Trail Blazer
Printers and Publishers, Bangalore, 203 pp.
Page, N.V., Q. Qureshi, G.S. Rawat & C.G. Kushalappa (2010). Plant diversity in
sacred forest fragments of Western Ghats: a comparative study of four life
forms. Plant Ecology 206(2): 237–250. https://doi.org/10.1007/s11258-009-9638-8
Page, N.V. & K. Shanker
(2018). Environment and dispersal influence changes in species
composition at different scales in woody plants of the Western Ghats, India. Journal
of Vegetation Science 29(1): 74–83. https://doi.org/10.1111/jvs.12586
Page, N.V. & K. Shanker
(2020). Climatic stability drives latitudinal trends in range
size and richness of woody plants in the Western Ghats, India. PLOS ONE
15(7): e0235733. https://doi.org/10.1371/journal.pone.0235733
Page, N.V., S. Kasinathan,
K. Bhat, G. Moorthi, T. Sundarraj,
D. Mudappa & T.R.S. Raman (2022). Data from: A new
population record of Critically Endangered Dipterocarpus
bourdillonii Brandis from the Anamalai
Tiger Reserve, Tamil Nadu. Dataset. Zenodo. https://doi.org/10.5281/zenodo.6799251
Pascal, J.P. (1988). Wet evergreen forests
of the Western Ghats of India: Ecology, structure, floristic composition and
succession. Institute Français de Pondichéry, Pondicherry, 345 pp.
Pascal, J.P. & B.R. Ramesh (1997). A field key to the
trees and lianas of the evergreen forests of the Western Ghats (India), Second edition. Institut Français de Pondichéry, Pondicherry, 236 pp.
POWO (2022). Plants of the World
Online. Royal Botanic Gardens, Kew. http://www.plantsoftheworldonline.org/
ACCESSED 8 August 2022.
Puttaswamy, H., C.G. Kushalappa, K.V. Ajayan &
B.N. Sathish (2010). Distribution and population status of a
Critically Endangered tree species Dipterocarpus
bourdillonii Brandis in Central Western Ghats.
In: Proceedings of the 15th International Forestry and Environment
Symposium, pp. 150–154. Department of Forestry and Environmental Science,
University of Sri Jayewardenepura, Sri Jayewardenepura, Sri Lanka, 377 pp. https://doi.org/10.31357/fesympo.v15i0.174
Ramesh, B.R. & J.-P. Pascal (1997). Atlas of Endemics of
the Western Ghats (India): Distribution of Tree Species in The Evergreen and
Semi-evergreen Forests. Institut Français de Pondichéry,
Pondicherry, 403pp.
Ramesh, B.R., N. Ayyappan, P. Grard,
J. Prosperi, S. Aravajy
& J.-P. Pascal (2010). Western Ghats v.1.0 - A multimedia
identification system of evergreen species of the Western Ghats, India. Institut Français de Pondichéry, Pondicherry.
https://www.ifpindia.org/digitaldb/online/biotik/
Sreekumar, V.B., T.B. Suma & K.A. Sreejith (2021).
Systematics, phylogeny and biogeography of
dipterocarps in the Western Ghats. KFRI Technical Report No. ISSN
0970-8103. Peechi, Thrissur: Kerala Forest Research
Institute.
Swarupanandan, K., E.P. Indira,
E.M. Muralidharan, R.C. Pandalai,
P.A. Jose & M. Sanjappa (2013). Species recovery of Dipterocarpus bourdillonii and Humboldtia bourdillonii, two
critically endangered endemic trees of Western Ghats. KFRI Research
Report No. 463. Kerala Forest Research Institute, Peechi,
86 pp.