Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 January 2021 | 13(1): 17587–17591
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.6095.13.1.17587-17591
#6095 | Received 04 May 2020 | Final received
23 December 2020 | Finally accepted 27 December 2020
Ecological importance of two
large heritage trees in Moyar River valley, southern
India
Vedagiri Thirumurugan
1, Nehru Prabakaran 2, Vishnu Sreedharan Nair 3 & Chinnasamy
Ramesh 4
1–4 Wildlife Institute of India, P.O.
Box 18, Chandrabani, Dehradun, Uttarakhand 248001,
India.
1 thirumurugan771@gmail.com, 2
nehrumcc@gmail.com (corresponding author), 3 vishnusreedharannair@gmail.com,
4 ramesh.czoo@gmail.com
Editor: Anonymity
requested. Date of publication:
26 January 2021 (online & print)
Citation: Thirumurugan,
V., N. Prabakaran, V.S. Nair & C. Ramesh (2021). Ecological importance of two
large heritage trees in Moyar River valley, southern
India. Journal of
Threatened Taxa 13(1): 17587–17591. https://doi.org/10.11609/jott.6095.13.1.17587-17591
Copyright: © Thirumurugan
et al. 2021. 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: Science and
Engineering Board SERB-DST- Extra Mural Grant
(EMR/2016/003963)
Competing interests: The authors
declare no competing interests.
Acknowledgements: This paper is an outcome of a
research project funded by DST-SERB-Extra Mural Grant (EMR/2016/003963),
Government of India. Our heartfelt
thanks to the principal chief conservator of forests and chief wildlife warden,
Tamil Nadu, field directors, chief conservator of forests, and district forest
officers, Sathyamangalam and Mudumalai
Tiger Reserves for granting permission to survey the area as well as the timely
help during the field visit; the other
team members Indian Python Project for their guidance and moral supports;
Narasimhan D., Devanathan K., and Bagath
Singh for their support; and the research coordinator, dean, & the director
at Wildlife Institute of India, Dehradun for their support and encouragements.
Large old trees are considered as
‘keystone structures’ because of their humungous size and disproportionately
high production of resources for multiple species in an ecosystem (Manning et
al. 2006). They play a significant role
in providing ecological services and maintaining the ecosystem function in
various ecosystems (Lindenmayer et al. 2013; Lindenmayer & Laurance
2017). Large old trees are often called
heritage trees for their natural and cultural significance as they function as
critical habitat for a wide array of species in large landscapes (Dean et al.
1999; Jim 2017). The decline of large
old trees would negatively influence the environment, and the species that
depend on them may even face the risk of local extinction, thus affecting the
ecological integrity (Manning et al. 2006; Lindenmayer
et al. 2013; Lindenmayer & Laurance
2017).
Numerous animals, including
insects, reptiles, birds, herbivores, carnivores, and other species immensely
depend on large trees for shelter, shade, and food, especially in tropical dry
forests that usually support large populations of emblematic species like
tigers, leopards, and elephants. The
large old trees are also the major contributors to the high heterogeneity and
biomass of forest landscapes across the globe (Das et al. 2018). Most importantly, they occur at low stem
densities, yet influence spatial patterns over long inter-tree distances (Lutz
et al. 2018). Despite their significant
role in maintaining the ecological flows, the importance of large trees is
often understudied and overlooked in habitat conservation programs (Lutz et al.
2018).
The Moyar
River valley landscape (henceforth MRVL) at the juncture of the Western Ghats
and the Eastern Ghats is one among the dry tropical landscape, which supports
rich flora, fauna, and act as a habitat for many endangered and heritage
species. Especially, the riverine forest
along the Moyar River (a major perennial river in the
landscape) is one of the remaining contiguous forests in the Nilgiri Biosphere Reserve.
The large trees in landscapes like MRVL have special ecological
significance as they provide microhabitat for numerous species that have high
conservation significance. During the
two years (November 2017–January 2020) of vegetation survey that included 500
plots (10m x 10m) established across five major forest types in the MRVL, we
came across two large old trees one each of Terminalia arjuna (Roxb.) Wight. & Arn. and
Hardwickia binata
Roxb. This
article is an attempt to exemplify the ecological significance of these two
large old trees in the Moyar River valley landscape
(Figure 1).
We recorded an enormous tree of Terminalia
arjuna (Combretaceae) measuring 32m height and
8.45m girth at breast height (GBH; above buttress) at 11.5940N &
76.8460E, 398m (Image 1).
This individual tree occurs in the riparian forest along the Moyar River, where the average canopy height reaches around
25m. This particular tree is a unique
landscape feature that marks the tri-junction boundary of three tiger reserves
(TR), namely Sathyamangalam TR, Mudumalai
TR, and Bandipur TR.
Likewise, the large individual tree of Hardwickia
binata (Fabaceae) measuring 21m in height and
4.24m in GBH was observed at 11.5370N & 77.0210E,
324m (Image 2). This individual tree is
located in the scrub forest, where the average canopy height is around 5m –
four-fold lesser than the observed large old tree.
Terminalia arjuna is a large deciduous tree (local
name: ‘Neermathi’) usually found along the river, dry
watercourse, and streams of tropical dry and moist forests in India and Sri
Lanka (Kundu & Schmidt 2015). The
ecological significance of T. arjuna in MRVL includes providing
habitat for many species, stabilizing the riverbanks, and trapping the
sediments as buttress roots act as an excellent soil binder. Also, the large crown, tall stature of T.
arjuna is often used by major faunal species such as Elephants, Muggers,
Leopards, Sloth Bears, Chital, Grey Langur, and Malabar Giant Squirrel for
various purposes. Hence, it is
considered a keystone species of the riparian forest in southern India (Sunil
et al. 2019).
The largest tree of T. arjuna with
14m GBH and an estimated age of 550 years was reported from Javvadhu
Hills of Tamil Nadu by Vijayasankar et al.
(2012). Though the tree that we observed
is not the largest ever reported, it has a high ecological value. For example, this individual tree is highly
used as a roosting site by four species of vultures, of which three are
Critically Endangered namely White-rumped Vulture
Gyps bengalensis (J.F. Gmelin,
1788), Red-headed Vulture Sarcogyps calvus (Scopoli, 1786), and Long-billed Vulture Gyps
indicus (Scopoli, 1786); and one is
endangered Egyptian Vulture Vulture percnopterus (Linnaeus, 1758) as per the IUCN Red List data. We have recorded seven nests of White-rumped Vulture on this tree during December 2019. Also many raptors, namely, the Brown Fish-owl
Ketupa zeylonensis
(Gmelin, 1788), Spot-bellied Eagle-owl Bubo nipalensis (Hodgson, 1836), Oriental Honey-buzzard
Pernis ptilorhynchus
(Temminck, 1821), Changeable Hawk-eagle Nisaetus cirrhatus (Gmelin, 1788), and Shikra Accipiter
badius (Gmelin, 1788)
are observed roosting on this tree.
Interestingly, the Spot-bellied Eagle-owl is a new record to the faunal
checklist of Sathyamangalam Tiger Reserve. These observations signify the conservation
importance of large old trees in general and the observed tree in particular.
Hardwickia binata
is native to
southern and southeastern Asia (Arunkumar
& Joshi 2018) representing the only species under the genus Hardwickia (Kumar & Sane 2003; Sanjappa 2010; Kundu & Schmidt 2011). The records suggest that this species can
grow up to 36m tall and 4m GBH (Arunkumar & Joshi
2018). The tree that we observed has the
largest GBH as per the available reports.
H. binata is one of the dominant
tree species in the tropical dry deciduous forest of southern India (Meher-Homji 2008).
It also commonly occurs in the southern tropical thorn forest, scrub
forest, deciduous forest, and woodland savannah of the MRVL (Champion &
Seth 1968). In MRVL, H. binata (locally called ‘Aacha’,
‘Aachamaram’ or ‘Karachi’) are commonly found along
the ridges, furrows, and hillocks.
In MRVL, H. binata remains as one of the essential foraging
trees for the herbivores where mammals generally prefer the leaves, twigs, and
bark. The Asian Elephant Elephas
maximus intemperately feeds on its bark, leaves, and act as a primary
seed-dispersing agent (Sukumar 1992; Baskaran et al. 2010). The Irula’s
(indigenous community in this landscape) also use this tree species for
multiple purposes (timber, firewood and to make ropes during local festivals)
indicating the cultural ethos associated with this species.
The growing evidence suggests
that the large old trees are globally on the decline due to various
environmental and anthropogenic drivers (Lindenmayer
et al. 2013). Experts particularly urge
that the conservation of large old trees require site-specific unique
conservation approaches (inclusive of social and cultural aspects) that span
over unprecedented spatio-temporal scales (Lindenmayer et al. 2013; Blicharska
& Mikusiński 2014; Lindenmayer
et al. 2014; Lindenmayer & Laurance
2016). In India, the conservation
mechanism adapted to the large Kannimara teak (Tectona grandis L.f.) that occur in Parambikulam
Tiger Reserve could serve as a model system for large old trees; where the
cultural heritage along with designating a special status (i.e., tree of
national importance) made an effective conservation tool for awareness building
(Nagarajan et al. 2010). Therefore,
implementing new policies to register and recognize the large old trees and
mapping their distributions will immensely help in their protection and
conservation of associated biodiversity.
Besides, future scientific studies focusing on the role that large old
trees play in biodiversity conservation and regulating the ecosystem process
could provide much-needed insights on the conservation significance of large
old trees; which is particularly crucial for the management of highly important
wildlife landscapes such as the Moyar River valley
landscape. Moreover, such initiatives
can play a vital role in the conservation awareness programs designed for local
stakeholders.
For
figure & images - - click here
References
Arunkumar, A.N. & G. Joshi (2018). Know Your Trees - Hardwickia binata
(Indian Black Wood). Forest genetic resources and tree improvement. ENVIS
Newsletter 4(4): 2–10.
Baskaran, N.,
M. Balasubramanian, S. Swaminathan & A.A. Desai (2010). Feeding ecology of the Asian
Elephant Elephas maximus Linnaeus in the Nilgiri
Biosphere Reserve, southern India. Journal of the Bombay Natural History
Society 107(1): 3.
Blicharska, M. & G. Mikusiński
(2014).
Incorporating social and cultural significance of large old trees in
conservation policy. Conservation Biology 28(6):
1558–1567.
Champion,
H.G. & S.K. Seth (1968). A Revised Survey of the Forest Types of India. Govt. India
Publication, Delhi, 404pp.
Das, A.J.,
A.J. Larson & J.A. Lutz (2018). Individual species-area
relationships in temperate coniferous forests. Journal of Vegetation Science
29(2): 317–324.
Dean, W.R.J.,
S.J. Milton & F. Jeltsch (1999). Large trees, fertile islands, and
birds in arid savanna. Journal of Arid Environments 41(1): 61–78.
Jim, C.Y.
(2017). Urban
heritage trees: Natural-cultural significance informing management and
conservation, pp. 279–306. In: Tan, P.Y. &
C.Y. Jim (eds.). Greening Cities: Forms and Functions. Springer, Singapore,
372pp.
Kumar, S.
& P.V. Sane (2003). Legumes of South Asia: A Check-list. Royal Botanic Gardens, Kew,
543pp.
Kundu, M.
& L.H. Schmidt (2011). Hardwickia binata
Roxb. Seed Leaflet 152: 1–2.
Kundu, M.
& L.H. Schmidt (2015). Terminalia Arjuna (Roxb.
ex DC) Wight & Arn. Seed Leaflet 166: 1–2.
Lindenmayer, D.B. & W.F. Laurance (2017). The ecology, distribution,
conservation, and management of large old trees. Biological Reviews
92(3): 1434–1458.
Lindenmayer, D.B. & W.F. Laurance (2016). The unique challenges of
conserving large old trees. Trends in Ecology & Evolution 31(6):
416–418.
Lindenmayer, D.B., W.F. Laurance,
J.F. Franklin, G.E. Likens, S.C. Banks, W. Blanchard, P. Gibbons, K. Ikin, D. Blair, L. McBurney & A.D. Manning (2014). New policies for old trees:
averting a global crisis in a keystone ecological structure. Conservation
Letters 7(1): 61–69.
Lindenmayer, D.B., W.F. Laurance
& J.F. Franklin (2013). Global decline in large old trees. Science 338(6112): 1305–1306.
Lutz, J.A.,
T.J. Furniss, D.J. Johnson, S.J. Davies, D. Allen, A. Alonso, K.J.
Anderson-Teixeira, A. Andrade, J. Baltzer K.M.L. Becker, E.M. Blomdahl,
N.A. Bourg, S. Bunyavejchewin, D.F.R.P. Burslem, C.A. Cansler, K. Cao, M.
Cao, D. Cárdenas, L. Chang, K. Chao, W.
Chao, J.M. Chiang, C. Chu, G.B. Chuyong, K. Clay, R. Condit, S. Cordell, H.S. Dattaraja, A. Duque, C.E.N. Ewango,
G.A. Fischer, C. Fletcher, J.A. Freund, C. Giardina,
S.J. Germain, G.S. Gilbert, Z. Hao, T. Hart, B.C.H. Hau,
F. He, A. Hector, R.W. Howe, C. Hsieh, Y. Hu, S.P. Hubbell, F.M. Inman-Narahari, A. Itoh, D. Janík, A.R.
Kassim, D. Kenfack, L.
Korte, K. Král,
A.J. Larson, Y. Li, Y. Lin, S. Liu, S. Lum, K. Ma, J.
Makana, Y. Malhi, S.M. McMahon, W.J. McShea, H.R. Memiaghe, X. Mi, M. Morecroft, P.M. Musili, J.A.
Myers, V. Novotny, A. de Oliveira, P. Ong, D.A. Orwig, R. Ostertag,
G.G. Parker, R. Patankar, R.P. Phillips, G. Reynolds,
L. Sack, G.M. Song, S. Su, R. Sukumar, I. Sun, H.S. Suresh, M.E. Swanson, S.
Tan, D.W. Thomas, J. Thompson, M. Uriarte, R.
Valencia, A. Vicentini, T. Vrška,
X. Wang, G.D. Weiblen, A. Wolf, S. Wu, H. Xu, T. Yamakura, S. Yap & J.K. Zimmerman (2018). Global importance of
large-diameter trees. Global Ecology and Biogeography 27(7): 849–864.
Manning,
A.D., J. Fischer & D.B. Lindenmayer (2006). Scattered trees are keystone
structures–implications for conservation. Biological conservation
132(3): 311–321.
Meher-Homji, V.M. (2008). Tropical dry deciduous forests of
peninsular India. Feddes Repertorium 88(1–2): 113–134. https://doi.org/10.1002/fedr.19770880106
Nagarajan,
B., M. Desha, S. Sarvesh,
A. Daniel & D. Jesubalan (2010). Kannimara
teak: an extant forest genetic resource. Current Science 99(7): 862.
Sanjappa, M. (2010). Legumes of India.
Dehradun. Bishen Singh Mahendra
Pal Singh, 132pp.
Sukumar, R.
(1992). The Asian
Elephant: Ecology and Management. Cambridge University Press, 478pp.
Sunil, C.,
R.K. Somashekar & B.C. Nagaraja
(2019). Influence of
Terminalia arjuna on the riparian landscapes of the River Cauvery of
south India. Landscape Research 44(8): 982–996.
Vijayasankar, R., K. Ravikumar & P.
Ravichandran (2012). Plant Resources of Tiruvannamalai District Tamil Nadu, India. Bishen Singh Mahendra Pal Singh,
Dehra Dun, 343pp.