Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 July 2021 | 13(8): 18993–19001
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7371.13.8.18993-19001
#7371 | Received 28 April 2021 | Final
received 20 June 2021 | Finally accepted 11 July 2021
Characterisation
of breeding habitat of Grizzled Giant Squirrel Ratufa
macroura (Mammalia: Sciuridae) in Chinnar Wildlife Sanctuary, Western Ghats, India
Kiran Thomas 1 &
P.O. Nameer 2
1 Department of Wildlife and
Habitat Management, Forest College and Research Institute, Osmania
University, Hyderabad, Mulugu, Telangana 502279,
India.
2 Centre for Wildlife Studies,
College of Forestry, Kerala Agricultural University, Thrissur, Kerala 680656,
India.
1 kiranzthomas@gmail.com, 2 nameer.po@kau.in
(corresponding author)
Editor: Honnavalli N. Kumara, Salim Ali
Centre for Ornithology and Natural History, Coimbatore, India. Date of publication: 26 July 2021
(online & print)
Citation: Thomas, K. & P.O. Nameer (2021). Characterisation
of breeding habitat of Grizzled Giant Squirrel Ratufa
macroura (Mammalia: Sciuridae) in Chinnar Wildlife Sanctuary, Western Ghats, India. Journal of Threatened Taxa 13(8): 18993–19001. https://doi.org/10.11609/jott.7371.13.8.18993-19001
Copyright: © Thomas & Nameer 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: Kerala Agricultural University.
Competing interests: The authors
declare no competing interests.
Author details: Kiran Thomas worked on ecology of the Grizzled
Giant Squirrel for his Master’s dissertation and is currently Assistant
Professor Department of Wildlife and Habitat Management in FCRI, Hyderabad. His
research interest is small mammal ecology. P.O.
Nameer is Professor & Head (Wildlife) with
Kerala Agricultural University and works primarily on the vertebrate ecology
and biogeography in the Western Ghats.
Author contributions: Both the authors contributed
equally to the design, implementation, data analysis and writing the
manuscript.
Acknowledgements: The authors would like to thank
the Chief Wildlife Warden, Kerala State Forest Department, for the study permit
(No. WL10-947/2013) and the Wildlife Warden, Asst. Wildlife Warden and other
staff of the Chinnar WLS for providing the logistic
support for the study. The Kerala Agricultural University provided financial
support for the conduct of the research. We also would like to thank Neelesh Dahanukar and Ashish Jha
for helping with the data analysis, while Sasidharan
N, Vishnu R, Kiran Mohan and Shine G helped us with the identification of the
plants. The support from the forest
watcher Ponnusamy at Chinnar
Wildlife Sanctuary and Akhil Das A. of College of Forestry during the fieldwork
has been immense and are greatly acknowledged.
The authors also thank two anonymous reviewers and the Subject Editor
for their critical comments, which helped improve the manuscript.
Abstract: The Grizzled Giant Squirrel (GGS)
Ratufa macroura (Pennant, 1769) is a
‘Near Threatened’ and endemic giant squirrel distributed in southern India and
Sri Lanka. In India, the species is distributed in more than 10 locations
between Cauvery Wildlife Sanctuary in Karnataka in the north and Srivilliputhur Grizzled Squirrel Wildlife Sanctuary in
Tamil Nadu in the south. A study was conducted in the riparian habitats of Chinnar Wildlife Sanctuary in Kerala to understand the
habitat characteristics, including the drey site use
of GGS. The vegetation of the GGS habitat was studied using the quadrat method,
and the dreys were counted using the transects. A total of 95 species of trees were
identified from the riverine vegetation, and the GGS used 36 species of trees
for drey construction. Most of the dreys were found on Mangifera
indica, Terminalia arjuna, Ficus
microcarpa, Diospyros ebenum,
and Pongamia pinnata.
However, the GGS may prefer trees such as Mitragyna
parviflora, Diospyros ebenum,
Ficus microcarpa, Albizia procera, Acacia nilotica, and Acacia leucophloea
for drey construction. The study also highlights the
usage of large trees with extensive crown by the GGS for various activities such
as feeding, resting, moving, and nesting, thus signifying the necessity for
protecting the remaining riverine habitat at Chinnar
Wildlife Sanctuary to ensure the long-term conservation of GGS. We recommend an
urgent restoration by restocking with already existing, native tree species of
the riverine habitat due to the extremely poor regeneration of trees in the
riverine habitat that support the only population of the GGS in Kerala.
Keywords: Conservation, drey
construction, Kerala, large trees, population, riverine habitat, vegetation.
INTRODUCTION
The Grizzled Giant Squirrel (GGS)
is endemic to southern India (Kerala, Karnataka, and Tamil Nadu) and Sri Lanka
(Image 1). GGS shows one of the most important paradigms of isolated
populations. In India, it is known to occur in severely fragmented locations,
and a few with connections including Srivilliputhur
Grizzled Squirrel Wildlife Sanctuary (Joshua & Johnsingh
1994), Theni Forest Division (Babu et al. 2013),
Palani Hills (Davidar 1989), Anamalai
Tiger Reserve (Kumar et al. 2002), Sirumalai (Sathasivam et al. 2008), Thiruvannamalai
Forest Division (Babu & Kalaimani
2014), Hosur Forest Division (Baskaran et al. 2011), Athur
& Dharmapuri (Paulraj 1991; Paulraj
& Kasinathan 1993), Pakkamalai
Reserve Forest, Gingee (Vimalraj
et al. 2018), Cauvery Wildlife Sanctuary-Shivanasamudra
Falls and Mekedatu on the Cauvery river basin
(Karthikeyan et al. 1992; Kumara & Singh 2006);
and Chinnar Wildlife Sanctuary (Chinnar
WS) in Kerala (Ramachandran 1989; 1993, Senthilkumar
et al. 2007; Thomas & Nameer 2018).
The GGS has three subspecies,
with one present in southern India while all the three subspecies present in
Sri Lanka (Ellerman 1961; Moore & Tate 1965; Phillips 1984; Corbet &
Hill 1992; Menon 2014). Ratufa macroura dandolena is the smallest among the three races of GGS
globally and is seen in southern India and Sri Lanka. In comparison, the other
two races, Ratufa macroura macroura and Ratufa
macroura melanochra, are endemic to Sri Lanka.
The home range of the GGS is between 0.197 ha and 0.611 ha (Joshua 1992). There
are less than 500 mature individuals of GGS in India (Joshua et al. 2008; Goonatilake 2019). However, a recent study estimated the
population of the GGS and found a considerably low population in Chinnar WS than the previous estimate (Thomas & Nameer 2018).
Though the Chinnar
WS has an extent of 90.44 km2, the distribution of GGS is confined
to a narrow stretch of riparian vegetation along the Chinnar
and Pambar rivers and their tributaries. Either side
of this riparian vegetation is surrounded by scrub jungle to dry deciduous
forests not used by GGS. The actual extent of the riverine habitat preferred by
GGS comes to only 2 km2 which is around 2% of the total area of the
sanctuary. The previous studies on GGS in Chinnar WS
(Ramachandran 1989, 1993; Senthilkumar et al. 2007;
Thomas & Nameer 2018) revealed that the animal’s
habitat is patchy in distribution and limited by the treeless areas in Chinnar WS (Ramachandran 1993). However, in Srivilliputhur WS and Sri Lanka, the GGS exploits the plantations
of mango, coconut, and tamarind (Joshua 1992; Phillips 1984). The significant
conservation challenges being faced by the GGS in Chinnar
are increased predation risk due to opening up of the canopy due to natural and
anthropogenic effects (Thomas et al. 2017), hybridisation
between GGS and Indian Giant Squirrel (Thomas et al. 2018), disturbance in the
habitat because of tourism and road kills (Ramachandran 1993).
Although there are some studies
on the habitat and nesting behaviour of this species (Joshua
& Johnsingh 1994; Senthilkumar
et al. 2007), a detailed study on the drey site usage
of the species is not available. The information about drey
site usage will be helpful for the long-term conservation of GGS.
MATERIALS
AND METHODS
Study area
The study was conducted between
April 2013 to May 2014 in the Chinnar WS, Kerala,
southern India. It is located between Lat- 10.250–10.350, Long- 77.083–77.266
in the Kerala part of southern Western Ghats, in Idukki district (Figure 1).
Though the Chinnar WS supports the only known
population of GGS in Kerala, the GGS is seen in the Anamalai
Tiger Reserve, in Tamil Nadu too, which is adjacent to the Chinnar
WS. The terrain of Chinnar is undulating, with
altitudes ranging 440–2,372 m. Chinnar supports
different vegetation types such as southern tropical thorn forest (scrub
jungle), southern dry mixed deciduous forest (dry deciduous forest), southern
moist mixed deciduous forest (moist deciduous forest), tropical riparian
fringing forest (riparian forest), southern montane wet temperate forest (shola
forests), and southern montane wet grassland (grasslands) (Anonymous 2012;
Champion & Seth 1968). The dominant vegetation among these is the dry
deciduous forest followed by scrub jungle, mainly found in the plains and lower
altitudes. The dry deciduous and scrub jungle together constitute about 70% of
the total forest area in Chinnar (Thomas et al.
2017). However, the GGS in Chinnar WS are primarily
seen only in the riverine forests along the Chinnar
and Pambar rivers and tributaries which account for
only about 2% of the Chinnar WS (Ramachandran 1993;
Thomas & Nameer 2018).
Sampling of the Grizzled Giant
Squirrel dreys
Eight, 1,000 m long transects
were laid randomly after the reconnaissance survey done in the riparian
habitats of Chinnar WS. These transects were walked
twice a month for 12 months and recorded details of all the sighted dreys such as the number of dreys,
tree species, tree height, and drey height.
Vegetation sampling
A total of 100, 10 x 10 m, quadrats
were sampled for studying the vegetation in the riverine habitats in Chinnar WS. The 100m2
(10 x 10 m) quadrats were laid at every 100m on five transects in the riverine
habitats. In each quadrat, all trees with >10 cm GBH were enumerated, where
the name of each tree species, the height of the tree in meters and girth at
breast height in meters were recorded. The vegetation characters of tree
species were quantified by calculating the following eight parameters as
detailed below (after Pascal 1988).
Density (D) = Number of individuals/hectare
Number of individuals
of the species
Relative Density (RD) =
–––––––––––––––––– x 100
Number of individuals
of all species
Total Number of individuals of the species
Abundance (A) =
–––––––––––––––––––––––––––– Number of quadrats of occurrence
Number of quadrats of occurrence
Percentage Frequency (PF) =
––––––––––––––X 100 Total Number of quadrats studied
Percentage frequency of individuals
species
Relative Frequency (RF) = ––––––––––––––– X 100 Sum Percentage Frequency of all species
GBH 2
Basal Area (BA) = –––––
4П Basal area of the species
Relative Basal Area (RBA) =
–––––––––––––––X 100 Basal area of all species
Important Value Index (IVI) = RD
+ RF + RBA
Statistical analysis
We calculated the selectivity
index (Ivlev 1961) to find out the relationship
between the vegetation and the drey site preference
by the GGS. We also performed a linear regression model to find out the
relationship between the height of the tree species and the drey
height.
RESULTS
Tree species composition and
diversity in riparian habitat at Chinnar Wildlife
Sanctuary
A total of 95 tree species were
recorded from the riparian habitats of Chinnar WS.
The ten most dominant tree species in the GGS habitat were Pongamia
pinnata, Terminalia arjuna, Mangifera
indica, Pterocarpus
marsupium, Alphonsea sclerocarpa,
Ficus benghalensis, Syzygium cumini, Ficus microcarpa, Sapindus tetraphylla, and
Spondias pinnata (Table
1). The riparian habitat of the GGS is also characterised
by a tree density of 862 trees per hectare and a tree basal area of 7.13 m2/ha.
Characterising of the drey
site occurrence of Grizzled Giant Squirrels
The GGSs
were found to be using about 36 trees in Chinnar WS
for drey construction (Table 2), and a total of 144 dreys were recorded. The following five species were found
holding 54.86 % of the total dreys. The five species
were Mangifera indica
(n= 19) Terminalia arjuna (n= 18), Ficus
microcarpa (n= 16), Diospyros ebenum (n= 14), and Pongamia
pinnata (n= 12). The correlation studies between
the important value index (IVI) of the trees and drey
numbers showed (Figure 2) that there is no correlation between the dominant
trees and the drey selection. This also suggests that
the choice of nesting trees by the GGS is not random, and going by the ranks of
the Ivlev index indicate that the GGS may have a
preference for the trees such as Mitragyna parviflora, Diospyros ebenum, Ficus microcarpa, Albizia procera, Acacia nilotica, and Acacia leucophloea
for drey construction.
Regeneration
of the trees in the riverine habitat in Chinnar WS
The
regeneration of the trees used by the GGS for drey
construction was extremely low in Chinnar WS (Figure
3), as evidenced by the absence of individuals in the lower girth classes for
most tree species. Ideally, the girth class distribution of the tree species in
an undisturbed forest should have been showing an inverse ‘J’ pattern (Pascal
1988). In contrast, at Chinnar riverine patch, the
plants with lower girth classes were more or less completely absent for most of
the trees except Pongamia pinnata.
Relationship
between the tree height and the drey height
The linear regression model analysis clearly showed a strong correlation
between the height of the tree and the height at which the drey
was constructed (R= 0.9483, P <0.0001) (Figure 4). It can also be deduced
from this graph that the GGSs showed more significant variation in the height
of the trees used to construct the dreys, which
varied from 5 m to 30 m (Figure 4), with most of the drey
height being between 15 to 20 m. However, it is interesting to note that the
tree height influences the drey height in the
respective habitat (Figure 5a,b).
DISCUSSION
The GGS were found using large,
mature trees for the drey construction in the
riverine habitat at Chinnar WS. The dreys were built just below the canopy of the trees. GGS’s
usually prefer significantly larger trees with greater girth and taller trees
with multiple branches for drey construction (Senthilkumar et al. 2007). The selection of mature trees
with greater canopy continuity could facilitate easy movement to and from the drey in all directions, equip the animal by providing a
significant advantage to escape from predators and to move to other parts of
the home range for foraging and other activities. The extent to which GGS is
using a habitat depends on the composition of tree species and structural
attributes of the forests canopy, predominantly the canopy continuum.
Discontinuous forests are known to restrict their movement and dispersal
because of their arboreal habit. Most of the arboreal dwellers and GGS prefer
those habitats that provide dense canopy cover and higher canopy height
(Baskaran et al. 2011; Nagarajan et al. 2011).
The observations in this study corroborate the findings of previous
studies that giant squirrels prefer areas with canopy connectivity to live and
build their dreys (Baskaran et al. 2011). The first
branching height of the tree increases with its total height; hence the drey would have to be higher on taller trees. This may be
helping the animal to escape from predation and effective utilisation
of its entire home range for resources.
The GGS in Chinnar WS was found to construct
globular dreys using leaves and twigs. One pair of
GGS makes multiple dreys within their home range,
similar to other giant squirrels (Prater 1971; Srinivas et al. 2008). The GGS
was found to construct multiple dreys at a time. The
construction and use of multiple dreys might provide
conveniently placed insulated nesting places throughout the territory or reduce
drey predation (Borges 2015). Drey
rotation may also help to avoid extremes of weather conditions like temperature
and rainfall. The rotation of the drey will also
reduce ectoparasite load.
In the Sitanadi WS, 77.68% of the dreys of giant squirrels were found on deciduous trees, while
22.32 % were located on the evergreen trees (Kanoje
2008). However, in the present study, 73.61 % of nesting trees were evergreen.
The extremely
poor regeneration of the tree species used by the GGS for the drey construction at Chinnar WS
is a matter of concern. It warrants
urgent restoration programmes at Chinnar
riverine habitat with the most suitable native tree species.
Table 1. Vegetation
characteristics of riparian habitat of Chinnar
Wildlife Sanctuary, Western Ghats, India.
|
Tree species@ |
D |
RD |
A |
PF |
RF |
BA |
RBA |
IVI |
RIVI |
|
Pongamia pinnata |
182 |
21.11 |
2.60 |
3.50 |
12.99 |
0.03 |
0.45 |
34.55 |
11.52 |
|
Terminalia arjuna |
74 |
8.58 |
1.45 |
2.55 |
9.46 |
0.23 |
3.28 |
21.33 |
7.11 |
|
Mangifera indica |
48 |
5.57 |
1.45 |
1.65 |
6.12 |
0.21 |
2.91 |
14.60 |
4.87 |
|
Pterocarpus marsupium |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.87 |
12.22 |
12.52 |
4.17 |
|
Alphonsea sclerocarpa |
53 |
6.15 |
3.12 |
0.85 |
3.15 |
0.04 |
0.52 |
9.82 |
3.27 |
|
Ficus benghalensis |
4 |
0.46 |
1.00 |
0.20 |
0.74 |
0.56 |
7.88 |
9.09 |
3.03 |
|
Syzygium cumini |
26 |
3.02 |
1.53 |
0.85 |
3.15 |
0.17 |
2.46 |
8.63 |
2.88 |
|
Ficus microcarpa |
25 |
2.90 |
1.32 |
0.95 |
3.53 |
0.09 |
1.31 |
7.73 |
2.58 |
|
Sapindus tetraphylla |
22 |
2.55 |
1.38 |
0.80 |
2.97 |
0.02 |
0.32 |
5.84 |
1.95 |
|
Spondias pinnata |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.38 |
5.33 |
5.63 |
1.88 |
|
Lepisanthes senegalensis |
19 |
2.20 |
1.46 |
0.65 |
2.41 |
0.07 |
0.95 |
5.57 |
1.86 |
|
Diospyros ebenum |
23 |
2.67 |
1.92 |
0.60 |
2.23 |
0.04 |
0.61 |
5.51 |
1.84 |
|
Melia dubia |
7 |
0.81 |
1.40 |
0.25 |
0.93 |
0.27 |
3.76 |
5.50 |
1.83 |
|
Psychoteris subintegra |
23 |
2.67 |
1.77 |
0.65 |
2.41 |
0.01 |
0.08 |
5.16 |
1.72 |
|
Ficus racemosa |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.30 |
4.22 |
4.83 |
1.61 |
|
Mallotus philippensis |
14 |
1.62 |
1.27 |
0.55 |
2.04 |
0.04 |
0.53 |
4.20 |
1.40 |
|
Jatropha sp. |
18 |
2.09 |
1.64 |
0.55 |
2.04 |
0.00 |
0.06 |
4.19 |
1.40 |
|
Emblica officinalis |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.28 |
3.88 |
4.18 |
1.39 |
|
Gyrocarpus asiaticus |
13 |
1.51 |
1.44 |
0.45 |
1.67 |
0.05 |
0.77 |
3.95 |
1.32 |
|
Calophyllum inophyllum |
5 |
0.58 |
1.67 |
0.15 |
0.56 |
0.19 |
2.70 |
3.83 |
1.28 |
|
Albizia odoratissima |
6 |
0.70 |
1.50 |
0.20 |
0.74 |
0.17 |
2.36 |
3.80 |
1.27 |
|
Schleichera oleosa |
11 |
1.28 |
1.10 |
0.50 |
1.86 |
0.04 |
0.60 |
3.73 |
1.24 |
|
Albizia lebbeck |
3 |
0.35 |
1.50 |
0.10 |
0.37 |
0.20 |
2.84 |
3.56 |
1.19 |
|
Manilkara hexandra |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.22 |
3.06 |
3.36 |
1.12 |
|
Artocarpus hirsutus |
10 |
1.16 |
1.25 |
0.40 |
1.48 |
0.04 |
0.57 |
3.21 |
1.07 |
|
Euphorbia sp. |
14 |
1.62 |
1.75 |
0.40 |
1.48 |
0.01 |
0.08 |
3.19 |
1.06 |
|
Tamarindus indica |
11 |
1.28 |
1.10 |
0.50 |
1.86 |
0.01 |
0.00 |
3.13 |
1.04 |
|
Hopea parviflora |
7 |
0.81 |
1.00 |
0.35 |
1.30 |
0.07 |
0.97 |
3.08 |
1.03 |
|
Dalbergia latifolia |
10 |
1.16 |
2.00 |
0.25 |
0.93 |
0.05 |
0.75 |
2.84 |
0.95 |
|
Garuga floribunda |
5 |
0.58 |
1.00 |
0.25 |
0.93 |
0.09 |
1.33 |
2.84 |
0.95 |
|
Cassia fistula |
9 |
1.04 |
1.50 |
0.30 |
1.11 |
0.05 |
0.67 |
2.82 |
0.94 |
|
Chloroxylon swietenia |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.15 |
2.08 |
2.68 |
0.89 |
|
Commiphora caudata |
10 |
1.16 |
1.67 |
0.30 |
1.11 |
0.03 |
0.39 |
2.66 |
0.89 |
|
Gmelina arborea |
10 |
1.16 |
2.00 |
0.25 |
0.93 |
0.04 |
0.57 |
2.65 |
0.88 |
|
Garcinia
gummi-gutta |
7 |
0.81 |
1.17 |
0.30 |
1.11 |
0.05 |
0.65 |
2.57 |
0.86 |
|
Ceiba pentandra |
2 |
0.23 |
2.00 |
0.05 |
0.19 |
0.15 |
2.08 |
2.49 |
0.83 |
|
Bauhinia racemosa |
6 |
0.70 |
1.50 |
0.20 |
0.74 |
0.06 |
0.87 |
2.31 |
0.77 |
|
Stereospermum chelonoides |
5 |
0.58 |
1.25 |
0.20 |
0.74 |
0.07 |
0.97 |
2.29 |
0.76 |
|
Albizia procera |
6 |
0.70 |
1.20 |
0.25 |
0.93 |
0.04 |
0.58 |
2.21 |
0.74 |
|
Canarium strictum |
5 |
0.58 |
1.00 |
0.25 |
0.93 |
0.05 |
0.67 |
2.17 |
0.72 |
|
Vitex altissima |
3 |
0.35 |
3.00 |
0.05 |
0.19 |
0.11 |
1.59 |
2.12 |
0.71 |
|
Cassine paniculata |
6 |
0.70 |
1.50 |
0.20 |
0.74 |
0.05 |
0.68 |
2.12 |
0.71 |
|
Anthocephalus cadamba |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.13 |
1.78 |
2.08 |
0.69 |
|
unidentified sp.2 |
4 |
0.46 |
1.00 |
0.20 |
0.74 |
0.06 |
0.87 |
2.08 |
0.69 |
|
Santalum album |
7 |
0.81 |
1.17 |
0.30 |
1.11 |
0.01 |
0.15 |
2.07 |
0.69 |
|
Olea dioica |
5 |
0.58 |
1.25 |
0.20 |
0.74 |
0.05 |
0.67 |
1.99 |
0.66 |
|
Phyllanthus emblica |
5 |
0.58 |
1.25 |
0.20 |
0.74 |
0.04 |
0.61 |
1.94 |
0.65 |
|
Garuga pinnata |
8 |
0.93 |
2.00 |
0.20 |
0.74 |
0.02 |
0.26 |
1.93 |
0.64 |
|
Randia dumetorum |
6 |
0.70 |
1.00 |
0.30 |
1.11 |
0.01 |
0.08 |
1.89 |
0.63 |
|
Acacia leucophloea |
6 |
0.70 |
2.00 |
0.15 |
0.56 |
0.04 |
0.63 |
1.88 |
0.63 |
|
Strychnus nux-vomica |
5 |
0.58 |
1.25 |
0.20 |
0.74 |
0.04 |
0.53 |
1.86 |
0.62 |
|
Drypetes sepiaria |
5 |
0.58 |
1.25 |
0.20 |
0.74 |
0.04 |
0.50 |
1.83 |
0.61 |
|
Strychnos potatorum |
5 |
0.58 |
1.25 |
0.20 |
0.74 |
0.03 |
0.45 |
1.77 |
0.59 |
|
Ficus albiphyla |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.10 |
1.46 |
1.76 |
0.59 |
|
Anogeissus latifolia |
6 |
0.70 |
2.00 |
0.15 |
0.56 |
0.03 |
0.38 |
1.63 |
0.54 |
|
Azadirachta indica |
4 |
0.46 |
1.00 |
0.20 |
0.74 |
0.02 |
0.30 |
1.51 |
0.50 |
|
Ixora brachiata |
4 |
0.46 |
1.00 |
0.20 |
0.74 |
0.02 |
0.25 |
1.45 |
0.48 |
|
Mitragyna parvifolia |
3 |
0.35 |
1.00 |
0.15 |
0.56 |
0.03 |
0.47 |
1.38 |
0.46 |
|
Memecylon umbellatum |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.05 |
0.77 |
1.38 |
0.46 |
|
Ficus sp. |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.05 |
0.74 |
1.34 |
0.45 |
|
unidentified sp.8 |
5 |
0.58 |
1.25 |
0.20 |
0.74 |
0.03 |
0.01 |
1.33 |
0.44 |
|
Excoecaria oppositifolia |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.05 |
0.70 |
1.30 |
0.43 |
|
Mallottus alba |
5 |
0.58 |
2.50 |
0.10 |
0.37 |
0.02 |
0.34 |
1.29 |
0.43 |
|
Streblus asper |
4 |
0.46 |
1.33 |
0.15 |
0.56 |
0.01 |
0.18 |
1.20 |
0.40 |
|
Aporosa cardiosperma |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.06 |
0.85 |
1.15 |
0.38 |
|
Acacia nilotica |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.04 |
0.52 |
1.12 |
0.37 |
|
Ziziphus oenoplia |
4 |
0.46 |
1.33 |
0.15 |
0.56 |
0.01 |
0.09 |
1.11 |
0.37 |
|
Canthium umbellatum |
5 |
0.58 |
2.50 |
0.10 |
0.37 |
0.01 |
0.15 |
1.10 |
0.37 |
|
Crotalaria pellida |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.03 |
0.47 |
1.08 |
0.36 |
|
Holigarna arnotiana |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.05 |
0.75 |
1.06 |
0.35 |
|
unidentified sp.4 |
4 |
0.46 |
2.00 |
0.10 |
0.37 |
0.01 |
0.20 |
1.03 |
0.34 |
|
Ziziphus xylopyrus |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.05 |
0.70 |
1.00 |
0.33 |
|
Manilkara roxburghiana |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.02 |
0.35 |
0.95 |
0.32 |
|
Grewia tiliifolia |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.04 |
0.63 |
0.93 |
0.31 |
|
Alseodaphnae semecarpifolia |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.02 |
0.32 |
0.92 |
0.31 |
|
Miliusa tomentosa |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.04 |
0.58 |
0.88 |
0.29 |
|
unidentified sp.6 |
3 |
0.35 |
1.50 |
0.10 |
0.37 |
0.01 |
0.14 |
0.86 |
0.29 |
|
Canthium dicoccum |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.02 |
0.25 |
0.85 |
0.28 |
|
unidentified sp.1 |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.03 |
0.47 |
0.78 |
0.26 |
|
Plumeria alba |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.03 |
0.47 |
0.78 |
0.26 |
|
Sapindus trifoliatus |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.01 |
0.17 |
0.77 |
0.26 |
|
Ziziphus mauritiana |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.01 |
0.15 |
0.76 |
0.25 |
|
Helicteres isora |
3 |
0.35 |
1.50 |
0.10 |
0.37 |
0.002 |
0.03 |
0.75 |
0.25 |
|
Lepisanthes tetraphylla |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.01 |
0.14 |
0.74 |
0.25 |
|
Bamboo sp. |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.01 |
0.12 |
0.73 |
0.24 |
|
Euphorbia trigona |
2 |
0.23 |
1.00 |
0.10 |
0.37 |
0.01 |
0.12 |
0.73 |
0.24 |
|
unidentified sp.3 |
3 |
0.35 |
3.00 |
0.05 |
0.19 |
0.01 |
0.17 |
0.70 |
0.23 |
|
Terminalia paniculata |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.03 |
0.38 |
0.68 |
0.23 |
|
unidentified sp.5 |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.03 |
0.38 |
0.68 |
0.23 |
|
Ailanthus triphysa |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.02 |
0.23 |
0.53 |
0.18 |
|
Acacia intsia |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.01 |
0.15 |
0.46 |
0.15 |
|
Ficus hispida |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.01 |
0.14 |
0.44 |
0.15 |
|
Acacia catechu |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.01 |
0.09 |
0.39 |
0.13 |
|
unidentified sp.7 |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.006 |
0.06 |
0.37 |
0.12 |
|
Chukrasia tabularis |
1 |
0.12 |
1.00 |
0.05 |
0.19 |
0.001 |
0.02 |
0.32 |
0.11 |
|
Total |
862 |
100 |
127.74 |
26.95 |
100 |
7.13 |
100 |
300 |
100 |
@—arranged in the descending
order of the IVI index value | D—density (trees/ha) | RD—relative density |
A—abundance | PF—percentage frequency | RF—relative frequency | BA—basal area
(m2/ha.) | RBA—relative basal area | IVI—important value index |
RIVI—relative important value index.
Table 2. Tree use preference by
Grizzled Giant Squirrel for drey construction at Chinnar Wildlife Sanctuary, Western Ghats, India.
|
Tree species@ |
Family |
Number of dreys |
Habit |
IVI |
Ivlev index |
|
Mitragyna parviflora |
Rubiaceae |
5 |
Deciduous |
1.38 |
0.567 |
|
Diospyros ebenum |
Ebenaceae |
14 |
Evergreen |
5.51 |
0.435 |
|
Ficus microcarpa |
Moraceae |
16 |
Evergreen |
7.73 |
0.349 |
|
Albizia procera |
Fabaceae |
4 |
Deciduous |
2.21 |
0.288 |
|
Acacia nilotica |
Fabaceae |
2 |
Deciduous |
1.12 |
0.282 |
|
Acacia leucophloea |
Fabaceae |
1 |
Deciduous |
0.63 |
0.227 |
|
Albizia lebbeck |
Fabaceae |
5 |
Deciduous |
3.56 |
0.168 |
|
Mangifera indica |
Anacardiaceae |
19 |
Evergreen |
14.6 |
0.131 |
|
Sapindus trifoliatus |
Sapindaceae |
1 |
Evergreen |
0.77 |
0.130 |
|
Hopea parviflora |
Dipterocarpaceae |
1 |
Evergreen |
0.97 |
0.015 |
|
Tamarindus indica |
Fabaceae |
3 |
Evergreen |
3.13 |
-0.021 |
|
Syzygium cumini |
Myrtaceae |
8 |
Evergreen |
8.63 |
-0.038 |
|
Terminalia arjuna |
Combretaceae |
18 |
Evergreen |
21.33 |
-0.085 |
|
Memecylon grande |
Melastomataceae |
1 |
Evergreen |
1.38 |
-0.160 |
|
Ficus racemosa |
Moraceae |
3 |
Evergreen |
4.83 |
-0.234 |
|
Melia dubia |
Meliaceae |
3 |
Deciduous |
5.5 |
-0.294 |
|
Alphonsea sclerocarpa |
Annonaceae |
5 |
Deciduous |
9.82 |
-0.325 |
|
Gyrocarpus asiaticus |
Hernandiaceae |
2 |
Deciduous |
3.95 |
-0.328 |
|
Garcinia gummi-gutta |
Guttiferae |
1 |
Evergreen |
2.57 |
-0.440 |
|
Dalbergia latifolia |
Fabaceae |
1 |
Deciduous |
2.85 |
-0.481 |
|
Pongamia pinnata |
Leguminosae |
12 |
Evergreen |
34.55 |
-0.484 |
|
Schleichera oleosa |
Sapindaceae |
1 |
Deciduous |
3.73 |
-0.577 |
|
Calophyllum inophyllum |
Guttiferae |
1 |
Evergreen |
3.83 |
-0.586 |
|
Psychotria subintegra |
Rubiaceae |
1 |
Evergreen |
5.16 |
-0.675 |
|
Ficus benghalensis |
Moraceae |
1 |
Evergreen |
9.09 |
-0.802 |
|
Pterocarpus marsupium |
Fabaceae |
1 |
Deciduous |
12.52 |
-0.852 |
@—arranged in the
descending order of Ivlev index
For
figure & images - - click here
REFERENCES
Babu, S. & A. Kalaimani
(2014). New site record of Grizzled Giant Squirrel Ratufa macroura from Thiruvannamalai
Forest Division, Eastern Ghats, Tamil Nadu, India. Journal of Threatened
Taxa 6(2): 5492–5493. https://doi.org/10.11609/JoTT.o3680.5492-3
Babu, S., G. Srinivas, H.N. Kumara, K. Tamilarasu & S. Molur (2013). CEPF Western Ghats Special Series: Mammals of
the Meghamalai landscape, southern Western Ghats,
India - a review. Journal of Threatened Taxa 5(15): 4945–4952. https://doi.org/10.11609/JoTT.o3596.4945-52
Baskaran, N.,
K. Senthilkumar & M. Saravanan (2011). A new site record of
the Grizzled Giant Squirrel Ratufa
macroura
(Pennant,
1769) in the Hosur
forest division, Eastern
Ghats, India and
its conservation
significance.
Journal of Threatened Taxa 3(6):
1837–1841. https://doi.org/10.11609/JoTT.o2632.1837-41
Borges, R.M. (2015). Indian Giant Squirrel (Ratufa indica), pp
483–500. In: Johnsingh, A.J.T & N. Manjrekar
(eds.). Mammals of South Asia- Vol. II. The University Press, India,
799pp.
Champion,
H.G. & S.K. Seth (1968). A Revised Survey of the Forest Types of India. Government of
India Press, Delhi, 404pp.
Corbet, G.B.
& J.E. Hill (1992). The Mammals of the Indo-Malayan region: A
systematic review. Natural History Museum Publications, Oxford University
Press, Oxford. 496 pp.
Davidar, P. (1989). Grizzled Giant Squirrel, Ratufa macroura – distribution in Kudirayar. Journal of the Bombay Natural History Society
86(3): 437.
Ellerman,
J.R. (1961). The fauna
of India including Pakistan, Burma and Ceylon. Mammalia –2nd Edition, Vol. 3.
Rodentia. The Zoological Survey of India, Calcutta, 884pp.
Goonatilake, de A. (2019). Ratufa
macroura. In The IUCN Red List of Threatened Species2019:e.T19381A22261644.
Downloaded on 13 July 2019. https://doi.org/10.2305/IUCN.UK.2019.1.RLTS.T19381A22261644.en
Hammer, Ø.,
D.A.T. Harper & P.D. Ryan (2001). Past: Paleontological Statistics
Software Package for education and data analysis. Paleontologia
Electronica 4: 1–9.
Joshua, J.
(1992). Ecology of
the endangered Grizzled Giant Squirrel (Ratufa
macroura) in Tamil Nadu, South India. Ph.D. Thesis. Bharathidasan
University, Tiruchirapalli, Tamil Nadu, 191pp.
Joshua, J.
& A.J.T. Johnsingh. (1994). Impact of biotic disturbances on
the habitat and population of the endangered Grizzled Giant Squirrel, Ratufa macroura in South India. Biological
Conservation 68: 29–34.
Joshua, J.,
W.L.D.P.T.S. de A. Goonatilake & S. Molur (2008). Ratufa macroura.
In IUCN 2010. IUCN Red List of Threatened Species. Downloaded on 06 June 2018.
Kanoje, R.S. (2008). Nesting sites of
Indian
giant squirrels
in Sitanadi Wildlife
Sanctuary, India.
Current Science 95: 882–884.
Karthikeyan,
S., J.N. Prasad & B. Arun (1992). Grizzled Giant
Squirrel Ratufa macroura Thomas and Wroughton at Cauvery valley in Karnataka. Journal of the
Bombay Natural History Society 89(3): 360–361.
Kumar, M.A., M. Singh, S.K.
Srivastava, A. Udhayan, H.N. Kumara
& A.K. Sharma (2002). Distribution patterns, relative abundance and management of mammals in
Indira Gandhi Wildlife Sanctuary, Tamil Nadu, India. Journal of the Bombay
Natural History Society 99(2): 184–210.
Kumara, H.N. & M. Singh (2006). Distribution and relative
abundance of giant squirrel and flying squirrel in Karnataka, India. Mammalia
70: 40–47.
Menon, V.
(2014). Indian
Mammals: A Field Guide. Hachette book publishing India Pvt. Ltd., Gurgaon, Haryana, 528pp.
Moore, J.C.
& G.H.H. Tate (1965). A study of diurnal squirrels, Sciurinae of the
Indian and Indo – Chinese subregion. Fieldiana Zoology 48: 1–351.
Nagarajan, B., S. Venkatesan, J. Mani, S.K. Srivastava
& A.A. Desai (2011). Some aspects
of the ecology of
the Indian Giant Squirrel
Ratufa indica (Erxleben, 1777) in the tropical
forests of
Mudumalai Wildlife
Sanctuary, southern India
and their conservation implications. Journal
of Threatened Taxa 3: 1899–1908. https://doi.org/10.11609/JoTT.o2593.1899-908
Pascal, J.P.
(1988). Wet
Evergreen Forests of Western Ghats of India: Ecology, Structure, Floristic
composition and Succession. French Institute, Pondicherry, 337pp.
Paulraj, S. (1991). Grizzled Giant Squirrel in the
final throes of extinction process. Zoos’ Print 6(10): 1–2.
Paulraj, S. & N. Kasinathan
(1993). Scanty
known Grizzled Giant Squirrel (Ratufa
macroura) of India: status and conservation. Indian Forester 119:
828–833.
Phillips,
W.W.A. (1984). Manual of
the Mammals of Sri Lanka. 3rd Edition. Wildlife and Nature Protection
Society of Sri Lanka, Sri Lanka.
Prater, S.H. (1971). The book of
Indian animals. Bombay Natural History
Society, Mumbai, 324 pp.
Ramachandran,
K.K. (1989). Endangered
Grizzled Giant Squirrel habitat. Journal of Bombay, Natural History Society
86 (1): 94–95.
Ramachandran,
K.K. (1993).
Status survey and distribution of
endangered Grizzled
Giant
Squirrel in
Chinnar Wildlife Sanctuary, Kerala, India.
Indian Journal
of Forestry 16(3): 226–231.
Sathasivam, K., V. Santharam,
K.V. Sudhakar & T.B. Narayanan (2008). An unreported population of the
Grizzled Giant Squirrel Ratufa macroura.
Journal of the Bombay Natural History Society 105(2): 213.
Senthilkumar, K., G. Agoramoorthy
& M.J. Hsu. (2007). Population
size, density and conservation
status of Grizzled Giant Squirrel in Chinnar
Wildlife
Sanctuary,
India. Mammalia
71: 89–94pp.
Srinivas, V.,
P.D.
Venugopal & S. Ram (2008). Site occupancy of
the
Indian Giant Squirrel
Ratufa indica (Erxleben)
in Kalakad-Mundanthurai
Tiger
Reserve,
Tamil
Nadu,
India. Current
Science 95(7): 889–894.
Thomas, K.
& P.O. Nameer (2018). Alarming population status of
the Grizzled Giant Squirrel (Ratufa
macroura) (Mammalia: Rodentia: Sciuridae) in Chinnar Wildlife Sanctuary, Western Ghats. Journal of
Threatened Taxa 10(10): 12350–12356.
https://doi.org/10.11609/jott.3536.10.10.12350-12356.
Thomas, K.,
A.A. Das & P.O. Nameer (2017). A report on the predation of Grizzled
Giant Squirrel (Ratufa macroura) by
Changeable Hawk-Eagle (Nisaetus cirrhatus), from Western Ghats, South India. Zoo’s
Print 32(4): 11–14.
Thomas, K.,
D.K. Vinodkumar, J. Mathews, M. Shaji
& P.O. Nameer (2018). A report on the possible
interbreeding between Grizzled Giant Squirrel Ratufa
macroura and Malabar Giant Squirrel Ratufa
indica from Chinnar
Wildlife Sanctuary, Kerala, southern Western Ghats. Journal of Threatened
Taxa 10(15): 13024–13028. https://doi.org/10.11609/jott.3995.10.15.13024-13028
Vimalraj, S., K. Raman, D.A. Reddy, B. Harikrishnan, B.M. Krishnakumar
& K.M. Selvan (2018). A new sight record and range extension of the Grizzled Giant
Squirrel Ratufa macroura dandolena (Mammalia: Rodentia: Sciuridae)
in the Eastern Ghats of southern peninsular India. Journal of Threatened
Taxa 10(1): 11240–11242. https://doi.org/10.11609/jott.3932.10.1.11240-11242