chapter viii food and feeding 8.1...
TRANSCRIPT
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CHAPTER VIII
FOOD AND FEEDING
8.1 Introduction
The elephant is the largest terrestrial mammal on earth and requires a great amount
of food and water. In the wild, an adult male elephant has spends as many as 18 hours
feeding, consuming as much as 280kg of food and 140-200 liters of water per day (John and
Subramanian, 1991). The seasonal movement of elephant in any habitat is also affected by
the availability of food and water. Elephants are classified as megaherbivores and consume
up to 150 kg of plant matter per day (McKay, 1973; Vancuylenberg, 1977). Therefore,
availability of food is a major determinant of carrying capacity of elephants in a given area.
The availability of the food resources and its distribution pattern has also affects the
distribution and time budgets and habitat utilization of the wildlife species.
8. 1.1 Elephant and food
Elephants are generalist feeder and has less discrimination than other herbivores
towards the consumption of food plants. They browse and graze on a variety of plants but
their proportions vary both in time and space. During the dry season, 70 % of an elephant's
diet is browse, while in the wet season, grasses make up the major pan of the diet when
available (Sukumar ,1989b). Elephants may feed on over a hundred plant species in an area
but plants from just a few botanical families may account for most of their total intake
(McKay, 1973; Sukumar, 1989b). Again, fruits are an important component of their diet in
rainforests (Olivier, 1978a). Elephants are hindgut fermenters with a fairly rapid gut transit
time and relatively low digestive efficiency (Benedict, 1936). Nonetheless, adequate
nutrition can be maintained on a relatively poor quality (low protein/high cellulose) diet
provided sufficient quantities of forage are available (Janis, 1976; Eltringham, 1982).
Elephants may spend 12-18 hours a day feeding, during which they may consume up to 10
% of their body weight as fresh weight fodder (Sukumar, 1989b; Vancuylenberg, 1977).
They also defecate about 15-18 times a day, producing large quantities of dung. The
recycling of dung is very important for nutrient cycling of the ecosystem and also helps
disperse seeds.
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Wild elephants may need to spend 70-80 % of their walking time in foraging in order
to maintain an adequate nutritional plane (Eisenberg, 1981; McKay, 1973). Elephants spend
from 70-90 % of their time on foraging and consume of about 100-300kg (wet mass) of
vegetation per day (Guy, 1976; Wyatt and Eltringham, 1974). The relatively inefficient
digestive system and the requirement for a comparatively higher food intake accounts for the
greater time spent in feeding by elephants (Wyatt and Eltringham, 1974).
Further, a decrease in the availability of food may motivate an animal to increase the
foraging effort. Although this can be reduced by a change in foraging strategy, the ultimate
objective of the animal may be to reduce foraging effort as continued foraging strategy as
continued foraging in a limited food availability context would simply increase the
nutritional requirement more than intake. So, the general tendency of the animal may be to
reduce the foraging costs and conserve body energy (Gates and Hudson, 1979). Therefore,
feeding and breeding parameters are dependent on availability of natural food and water
(Joshi et al., 2009).
Leaves, barks, twigs, herbs, roots, corns, flowers, fruits etc. can be eaten by Asian
elephants (McKay, 1973; Sukumar and Ramesh, 1995). It is also reported that, feeding
activity may be highly destructive in certain instances. Grasses are often ripped up and eaten
root, culm and leaf while trees may be pushed over or broken down in order to gain access
to fruits, leaves which are out of reach (Kurt, 1974; Lekagul and McNeely, 1977; Mueller-
Dombois, 1972). Male consumes a greater proportion of roots and other woody tissues than
females and fell trees 3-5 times more frequently than females (Guy, 1976; Stokke and du
Toit, 2000).
Grass quality, as determined by the concentration of nitrogen, phosphorus,
potassium, calcium and sodium is an important factor influencing the distribution of grazing
mammals (McNaughton, 1990; Olff et al., 2002; Prins, 1987). Young leaves discarded by
elephants during browsing and bark feeding may be eaten by deer or other animals which
otherwise would be unable to obtain access to these resources (Lekagul and McNeely,
1977). Numerous animal use elephant paths in traversing areas of dense undergrowth
(Lakagul and McNeely, 1977; McKay, 1973) and these paths may thereby function as
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corridors in promoting the movement of species between habitat patches. The opening up of
dense understorey and lower canopy vegetation promotes growth of grasses and forbs
favoured by other ungulates and various other herbivores. Elephant foraging activities thus,
can benefit various other mammalian species, especially grazing ungulates, by maintaining
earlier successional plant communities and ecotone areas at the expense of closed canopy
forest species. Though elephant competes directly with other herbivore species for access to
some plant resources, elephants also grate on the tall, lignified stems of mature grass stems
by elephants can stimulate new growth, increase primary productivity and improve the
accessibility of the underlying herbage to other herbivores (McNaughton, 1979).
8.1.2 Geophagy and Asian elephant
Geophagy is defined as the deliberate and regular consumption of earthy materials
such as soils, clays or sediments by animals and humans (Abrahams and Parsons, 1996) and
may function to supplement dietary mineral deficiencies (Heyman and Hartman, 1991;
Holdo et al., 2002; Klaus and Schmid, 1998; Kreulen and Jager, 1984; Mills and Milewski,
2007; Moe, 1993 ), alleviate gastrointestinal disorders (Houston et al., 2001; Kreulen, 1985;
Klaus and Schmid, 1998; Krishnamani and Mahaney, 2000; Mee et al., 2005).
Davies and Payne (1982) and Payne (1992) have suggested that availability of
sodium strongly influenced the distribution of large mammals, especially elephants and
rhinoceros, in Sabah. As elephants are known to be prone to sodium deficiency (Benedict,
1936; Olivier, 1978a). They visit certain soils rich in minerals for salt-lick (Sukumar,
1985a). Elephants and other herbivores have high sodium requirements and in many areas
mineral licks are of great importance to resident elephant populations (Lekagul and
McNeely, 1977; Seidensticker, 1984). Salt soils or friable rock are dug out with tusk or the
toenails of the forefeet and then consumed it with the trunk and ingested and unused
remainder is frequently utilized by other herbivore species (Lekagul and McNeely, 1977.).
The distribution of mineral licks may have marked effects on the movement patterns of
elephant populations in some areas and can be manipulated as a means for regulating
movements in some wild elephant populations (Seidensticker, 1984). Sukumar (1989b)
proposed that an Asian elephant needs 75-100 gm of sodium daily in order to avoid deficit.
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Salt licking behaviour of animals has been reported in several past studies. Weir
(1972, 1973) had reported preference of African elephants for water and soil with higher
sodium content.
8.1.3 Seed Dispersal and Feeding
During the feeding of Asian elephants along with the grass and leaves lots of seeds
are eaten. Seeds frequently pass unharmed through the digestive tract and may subsequently
germinate or be eaten by other animals (McKay, 1973). Seeds and tough skinned fruits eaten
by elephants frequently pass through the digestive tract intact. Birds and small mammals are
known to seek out dung piles to feed on undigested seeds, fruit, or plant material and various
coprophilic invertebrates (Eisenberg and Lochart, 1972; McKay, 1973; Vacuylenberg,
1977). Fungi frequently grow on in elephant dung and undigested seeds may germinate if
not subsequently eaten by other animals (Eisenberg and Lochart, 1972). The importance of
the Asiatic elephants in the seed dispersal of tropical forest plants is as yet poorly
documented. With the high vagility and extraordinary consumption potential inherent to this
species, Asiatic elephants provides excellent vehicle for redistributing seeds of many plant
species employing animal seed dispersal strategies (Janzen, 1983). Asian elephants eat fruits
when it is viable, defecating intact seeds, of which some later germinate in the dung
(Lekagul and McNeely, 1977; Ridley, 1930).
The dispersal of seeds by elephants through dung piles was reported by many authors
both in Africa and Asia (Alexandre, 1978; Barnes, 1982b; Buss, 1961; Khan, 1977; Short,
1981 and 1983; Sivaganesan and Sathyanarayana, 1993 and White et al., 1993).
Quantitative studies of feeding ecology of Asian elephants have been carried out in
grasslands in Sri Lanka (McKay, 1973; Vancuylenberg, 1977) and in Tropical rain forest in
Malaysia (Olivier, 1978a). Sukumar (1985a) had focused the proportion of browse and grass
ratio in relation to their availability in Eastern Ghats. Feeding strategy of elephants in micro
habitats of thorn forest was also carried out by Sivaganesan (1991) and Kamalakannan
(1992) in Eastern Ghats.
Study on the food and feeding of Asian elephant were done by Barnes (1982b),
Cheeran et al. (1997), Clauss et al. (2003), Danquah and Oppong (2006 and 2007), De Boer
et al. (2000), Dhakal and Ojha (1995), Goswami (1994), Hettiarchchi et al. (2005), Lihong,
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et al. (2007), Mercy (2002), Pradhan et al. (2008), Samansiri and Weerakoon (2007), Santra
et al. (2008), Sivaganesan and Johnsingh (1995), Sukumar (1990b), Sukumar and Ramesh
(1995) and Vancuylenburg (1977).
In Assam, Borah and Deka (2008) studied the food plants of Asian elephant in Rani
Reserved forest. Very much less study has been carried out on the food and feeding pattern
of Asian elephant in Assam including the Manas National Park. Feeding and nutritional
ecology may be the key to elephant conservation. Understanding the view that, what
elephants eat and how they choose their food should provide significant insight into
ecological requirements relevant for the management of wild elephant populations and their
habitats and for the mitigation of human-elephant conflicts. Hence, the present study has
been designed to study the Asian elephant food and feeding pattern in Manas National Park.
8. 2 Objective
The objective of present chapter was to study the food and feeding pattern of Asian
elephant in Manas National Park. To fulfill the above objective following research questions
have been answered.
1. What was the utilization of different plants as food by Asian elephant?
2. What were the feeding processes of Asian elephant in Manas National Park?
3. What were the annual and seasonal contributions offered by different types of plants
as Asian elephant food?
4. What were the feeding frequencies on different food plant species consumed by
Asian elephant?
5. What was the food selectivity of Asian elephant?
6. What were the staple food, dietary spectrum of Asian elephant and other foods than
the wild plants consumed by the Asian elephant?
7. Was the geophagy and seed dispersal by Asian elephant in Manas National Park
could be seen?
8.3 Methods
The methods for study the food habit and feeding requirements were summarized
below. The method for calculation of the dominance of different plant species was discussed
in earlier chapter III.
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8.3.1 Sampling of food and feeding
During study period each of the habitats were searched for elephants using on foot
method by following fresh trails of elephants to collect data on feeding habits. Five days in a
month were used for collecting data on food and feeding requirement of Asian elephant.
Whenever a group or single elephants were observed, their feeding behaviors were recorded,
till their disappearance from sight in Manas National Park. But, there were variation in the
feeding observations different seasons across different habitats. The uneven distribution of
Asian elephant in different habitats and time was the cause for this variation. The Asian
elephant food and feeding pattern observation and data collection were done by ‘dawn to
dusk’ sampling methods. The Scan Animal Sampling and Ad. Libitum Sampling (Altmann,
1974) methods were used in Manas National Park during study.
The elephant trails or a herd of elephants was followed and all the plants observed
for signs of being fed by elephants and parts of the plants eaten were recorded. In addition a
herbarium specimen, a leaf sample, a bark sample and if fruits were available, the sample of
seeds were also collected to develop a reference collection that was used during the
subsequent macroscopic analysis of dung samples. The plant species were identified with
the help of the elephant ‘Mahout’ and forest guards in Manas National Park. Unidentified
species were carried to laboratory to prepare herbarium, consequently consult with the
taxonomist of Assam Forest Department, BSI, Shillong and were later identified. The data
on elephant browsing, grazing and debarking were also collected. Here, Browsing means
eating leaves, buds, twigs, shoots of tree and shrubs (i.e. woody vegetation) (Owen-
Smith,1982; Shoshani,1992) and the graze means eating grass, forbs, etc.(Owen-
Smith,1982; Shoshani,1992); Debarking means tearing the plants bark by using tushes and
tusk and consequently feed on it.
Data were collected based on direct observation of Asian elephants. Asian elephant
feeding observations were collected both on solitary and groups for 4320 hours during the
study period from 2007-2011. The data were pooled together for various analysis of food
and feeding. The relative feeding frequency of elephant was calculated by using the
formula-
Relative feeding on Sp1 (%) =
Feeding time on Sp1
100 (� Feeding time on Sp
1+ Sp
2+ Sp
3+........+ Sp
n)
(Where, Sp1, Sp2, …,Spn = Food plant species of Asian elephant).
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8.3.2 Food Selectivity
The food selectivity of Asian elephant was calculated by using the following
formulae.
Selectivity (R ) of Sp1=
% of feeding records on Sp1
Relative dominance of Sp1
(Where, Sp1= Food plant species of Asian elephant).
Here, the food selectivity was the ratio of the percent of time spent and percent of
dominance of each plant species. The ratio ‘R’ indicated whether the consumed plant
species had an effect on availability in the habitat or outcome of the food selection. If the R
> 1, then it suggests strong selection of feeding activity and when R<1, then it suggests that,
the feeding occurs due to availability of particular food items. Again, if R = 1, then it
indicated that, the particular plant species was consumed as per its distribution and
dominance in the sampling quadrate.
8.3.3 Geophagy Study
The bioavailability of nutrients via geophagy was difficult to quantify given the
range of chemical conditions present within the alimentary system of different herbivores
(Healy, 1973). Several field visits were made to the park in order to confirm the elephant
geophagy sites reported by park officials and to observe the geophagy behaviour of
elephants. However, at some sites, soil eating could not be directly observed. However, all
the elephant geophagy locations were on the border with the Bhutan. All licks sampled
during this study were comprised subsoil or weathered rock. One sample of 100 gm. was
collected from each lick site with geological tools (hammer). Another sample was also
collected from the top soils of the nearby Manas National Park area within a radius of 500
meter from the respective salt lick sites, which was not licked to determine whether licks
were enriched in nutrients relative to local topsoil. Nutrient content, which provides an
indication of nutrients targeted by animals. Total Ca, Mg, K, Na, B, Mo, Mn, Co, Cu, Zn
and Se were analyzed by Sequential X-ray Fluorescence Spectrometer (XRF) in Department
of Instrumentation & USIC, Gauhati University, Guwahati.
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All samples were subsequently dried and stored in polythene bags. Samples were
then disaggregated after passing through a 2-mm aperture sieve and the <2 mm fraction was
used for the chemical and mineralogical analyses. Total content of major and trace elements
was measured by X-ray fluorescence spectrometry (XRF) using a Philips PW2400
automated sequential spectrometer. Quality control of the preparation and the instrumental
performances were checked using international reference samples SARM-46 and SARM-52,
which were prepared as unknown and measured with samples.
8.3.4 Seed dispersal study
Altogether 280 fresh dung piles from each all the three administrative ranges of
Manas National Park were collected in 2007-2011 covering all the four seasons of the year
viz. pre-monsoon, monsoon, retreating monsoon and winter. The samples were collected
from various habitats viz. short grassland, tall grassland, wet grassland, moist mixed
deciduous forest, semi-evergreen forest and evergreen forest. The samples were transported
to a germination site at the Dwimari camp in the middle of the MNP. The seeds in the dung
germinated and the seedlings were monitored for about 90 days in each season in four batch.
The species were identified and categorized into herbs, shrubs or trees with assistance from
the Department of Botany, Gauhati University. Seedlings observed in-situ in the elephant
were collected and transported to the germination site and reared for identification.
Additional data on seed were collected by searching through all undisturbed dung piles that
were encountered in the forest and confirmed to be less than three days old for identifiable
remains of seed. Proportional dispersal of seeds from each of the family were calculated by
using the following formulae from the data of the seed germinated from the Asian elephant
dung.
Proportional germination of family f1 = Species no under f1
(species no under f1+ f2+ f3+.............+ fn)
(Where, f1, f
2,….f
n = family of germinated seeds).
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8.4 Results
8.4.1 Relative dominance and frequency and frequency of food plants
(a) Grasses
During the present study it was found that, Asian elephants were utililizing 60
species of grasses under six families viz. Andropogaceae, Cyperaceae, Poaceae,
Polygonaceae, Tamaricaceae and Zingiberaceae (Appendix III) as food in MNP. Of the total
60 grass species utilized as food, 42 had relative dominance (%) <1, 8 had relative
dominance (%) 1-2 and 10 had relative dominance (%) 2< (Table 8.1). The Saccharum
elephantium was the highest ranked relative dominant species with relative dominance value
of 14.88 %; while the Digitaria pruriens was the lowest dominant species having relative
dominance value of 0.32 % (Appendix III).
(b) Short trees, Shrubs, Climbers, Herbs
Study also revealed that, Asian elephants were utilizing 15 species among the short
trees, shrubs, climbers, herbs under 9 families viz. Acanthaceae, Asteraceae, Leeaceae,
Mimosaceae, Papilionaceae, Portulacaceae, Rhamnaceae, Scrophulariaceae and Vitaceae
(Appendix III) as food in MNP. Of the total 15 plant species among short trees, shrubs,
climbers, herbs utilized as food, one had relative dominance (%) <1, 8 had relative
dominance (%) 1-2 and 6 had relative dominance (%) 2< (Table 8.1 ). The Leea asiatica
was the highest ranked relative dominant species with relative dominance value of 7.08 %;
while the Vitis planicaulis was the lowest dominant species having relative dominance value
of 0.6 %.
(c) Trees
It was found that, Asian elephants were utilizing 37 species of trees under 19
families viz. Anacardiaceae, Bixaceae, Bombacaceae, Caesalpiniaceae, Combretaceae,
Dilleniaceae, Dipterocarpaceae, Euphorbiaceae, Lacythidaceae, Lauraceae, Lythraceae,
Meliaceae, Mimosaceae, Moraceae, Myrtaceae, Papilionaceae, Rutaceae, Sterculiaceae and
Verbenaceae (Appendix III) as food in MNP. Of the total 37 tree species, 16 had relative
dominance (%) <1, 10 had relative dominance (%) 1-2 and 10 had relative dominance (%)
2< (Table 8.1). The Bombax ceiba was the highest ranked relative dominant species with
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relative dominance value of 16.90 %; while, the Shorea robusta was the lowest dominant
species having relative dominance value of 0.05 %.
Table 8.1 Showing the relative dominance of grasses, short trees, shrubs, climbers, herbs
and tree species in Manas National Park.
Relative
dominance
class
Relative dominance (%)
Grass Short trees, Shrubs,
Climbers, Herbs
Trees
0 - 1 42 1 16
1 - 2 8 8 10
2 - 3 1 2 3
3 - 4 5 0 3
4 - 5 1 0 1
5 - 6 0 1 1
6 -7 0 2 1
7 - 8 0 1 0
8 - 9 1 0 0
9 -10 0 0 0
10 -11 0 0 0
11- 12 0 0 0
12- 13 1 0 0
13- 14 0 0 0
14- 15 1 0 1
15- 16 0 0 0
16- 17 0 0 1
Total 60 15 37
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8.4.2 Utilization of different plant species as food by Asian elephant
During the study period it was found that, Asian elephant utilized 112 species of
plants as food in Manas National Park. However, variation was found in the total species
used as food plants in different seasons as food by Asian elephant. The seasonal utilization
of food plants species were as follows-
(a) Pre-monsoon Season
During the present study, it was found that, Asian elephants utilized total of 93 plant
species during monsoon season in Manas National Park. Among these 93 plants, highest of
54 species were grass, followed by tree (n=28), climbers (n=5), shrubs (n=3), short tree
(n=2) and least of one herb species (Table 8.2).
(b) Monsoon Season
In Manas National Park, the Asian elephants utilized total of 101 plant species
during monsoon season. Among these 101 plants, highest of 56 species were grass, which
was followed by tree (n=31), climbers (n=6), short trees (n=3), shrub species (n=3) herbs
and least of two herb species (Table 8.2).
(c)Retreating Monsoon Season
During retreating monsoon season the Asian elephants utilized total of 87 plant
species in MNP. Among these 87 plants, highest of 45 species were grass, which was
followed by tree (n=31), climbers (n=6), short trees (n=3), herbs (n=1) and shrub species
(n=1) (Table 8.2).
(d) Winter Season
During the present study it was found that, Asian elephants utilized a total of 80
plant species during winter season. Among these 80 plants, highest of 38 species were grass,
which was followed by tree (n=30), climbers (n=6), short trees (n=3), herbs (n=2) and least
of one shrub species (Table 8.2).
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Table 8.2 Showing the utilization of various plant species in different season of the year as
food by Asian elephant.
Plant Type Season
Pre-
monsoon
Monsoon Retreating
Monsoon
Winter
Tree species 28 31 31 30
Short Tree
species 2 3 3 3
Shrub species 3 3 1 1
Climbers
species 5 6 6 6
Herb species 1 2 1 2
Grass species 54 56 45 38
Total 93 101 87 80
8.4.3 Feeding process
The present study revealed that, annually Asian elephants were found to feed mostly
by grazing (49.34 %), followed by browzing (35.35 %) and least by debarking (15.31 %) the
food plants in Manas National Park (Table 8.3).
During pre-monsoon season, Asian elephants were found to feed mostly by grazing
(59.8 %), followed by browzing (27.45 %) and least by debarking (12.75 %) the food plants
in Manas National Park (Table 8.3).
The present study revealed that, during monsoon season Asian elephants were found
to feed mostly by grazing (61.36 %), followed by browzing (26.14 %) and least by
debarking (12.5 %) the food plants in Manas National Park (Table 8.3).
Study also revealed that, during retreating monsoon season Asian elephants were
found to feed mostly by grazing (54.29 %), followed by browzing (30 %) and least by
debarking (15.71 %) the food plants in Manas National Park (Table 8.3).
During winter season Asian elephants were found to feed mostly by grazing (57.14
%), followed by browzing (22.62 %) and least by debarking (20.24 %) the food plants in
Manas National Park (Table 8.3).
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Table 8.3 Asian elephant feeding process by means of grazing, browsing and debarking in
MNP (data in % basis).
Feeding
Pattern
Seasons Annual
Frequency
(%) Pre-
monsoon
Monsoon Retreating
Monsoon
Winter
Grazing 59.8 26.14 54.29 57.14 49.34
Browzing 27.45 61.36 30 22.62 35.35
Debarking 12.75 12.5 15.71 20.24 15.31
8.4.4 Annual and Seasonal Use of Food Plant Species
8.4.4.1. Annual
During present study, it was found that, grasses contributed highest of 69.35 % by
Asian elephant food annually, followed by contribution from climbers (16.56 %), trees
(11.03 %), short trees (2.79 %), shrubs (0.18 %) and least by herbs (0.09 %) in Manas
National Park (Figure 8.1; Table 8.4 ).
8.4.4.2. Seasonal Contribution
The seasonal contribution by different plants species as the food of Asian elephant in
Manas National Park were as follows-
(a) Pre-monsoon Season
During the present study it was found that, grasses contributed the highest of 72.27
% food of Asian elephant during the pre-monsoon season, followed by contribution by
climbers (14.99 %), trees (10.23 %), short trees (2.17 %), shrubs (0.28 %) and least by herbs
(0.05 %) in Manas National Park (Figure 8.1; Table 8.4 ).
(b) Monsoon Season
During the present study it was found that, grasses contributed the highest of 71.16
% food of Asian elephant during the monsoon season, followed by contribution by climbers
(15.83 %), trees (10.26 %), short trees (2.36 %), shrubs (0.27 %) and least by herbs (0.11 %)
in Manas National Park (Figure 8.1; Table 8.4 ).
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(c) Retreating Monsoon Season
During the present study it was found that, grasses contributed highest of 68.1 %
food of Asian elephant during the retreating monsoon season, followed by contribution from
climbers (16.05 %), trees (12.06 %), short trees (3.66 %), shrubs (0.08 %) and least from
herbs (0.05 %) in Manas National Park (Figure 8.1; Table 8.4 ).
(d) Winter Season
During the present study it was found that, grasses contributed highest of 65.87 %
food of Asian elephant during the winter season, followed by contribution from climbers
(19.38 %), trees (11.56 %), short trees (2.97 %), herbs (0.12 %) and least from shrubs (0.09
%) in Manas National Park (Figure 8.1; Table 8.4).
Figure 8.1 Showing the annual and seasonal utilization of food plants species by Asian
elephant in Manas National Park.
Table 8.4 Showing the annual and seasonal utilization of food plants by Asian elephant in
Manas National Park (data in % basis).
Plants Seasonal feeding % Annual
Feeding (%) PM M RTM WIN
Tree 10.23 10.26 12.06 11.56 11.03
Short Tree 2.17 2.36 3.66 2.97 2.79
Shrubs 0.28 0.27 0.08 0.09 0.18
Climbers 14.99 15.83 16.05 19.38 16.56
Herbs 0.05 0.11 0.05 0.12 0.09
Grass 72.27 71.16 68.10 65.87 69.35
PM-Pre-monsoon; M= Monsoon; RTM-Retreating Monsoon; WIN=Winter
10
.23
2.1
7
0.2
8
14
.99
0.0
5
72
.27
10
.26
2.3
6
0.2
7
15
.83
0.1
1
71
.16
12
.06
3.6
6
0.0
8
16
.05
0.0
5
68
.10
11.5
6
2.9
7
0.0
9
19
.38
0.1
2
65
.87
11
.03
2.7
9
0.1
8
16
.56
0.0
9
69
.35
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
Tree Short Tree Shrubs Climbers Herbs Grass
Fee
din
g (
%)
Plant types
Pre Monsoon
Monsoon
Retreating Monsoon
Winter
Annual Feeding (%)
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8.4.5 Feeding frequency
8.4.5.1 Annual feeding frequency
Study revealed that, the grass species Saccharum elephantium (8.81 %) was the
highest consumed food plant species of elephant in Manas National Park. While the
Lindernia crustacea (0.00058 %) was the lowest consumed food plant species by Asian
elephant in Manas National Park. Based on the annual feeding frequency, the ten top
ranking food plant species consumed by Asian elephant in Manas National Park were the
Saccharum elephantium (8.81%), Erianthus ravennae (7.47 %), Vetiveria zizanioides (6.4
%), Butea parviflora (5.37 %), Vitis planicaulis (4.42 %), Mikania micrantha (3.79 %),
Phragmites karka (3.62 %), Themeda villosa (2.96 %), Imperata cylindrica (2.77 %) and
Arundo donax (2.46 %) (Table 8.5). These top ten ranking food plant species of Asian
elephant were followed by feeding on other species described in Table 8.6.
Table 8.5 Showing the feeding frequency of ten top ranking annual food plants species of
Asian elephant in Manas National Park.
Sl. No. Species Annual Feeding
frequency
�� Saccharum elephantium 8.81
�� Erianthus ravennae 7.47
�� Vetiveria zizanioides 6.40
�� Butea parviflora 5.37
�� Vitis planicaulis 4.42
�� Mikania micrantha 3.79
�� Phragmites karka 3.62
� Themeda villosa 2.96
� lmperata cylindrica 2.77
��� Arundo donax 2.46
8.4.5.2 Seasonal feeding frequency
The seasonal feeding frequency of Asian elephant on different plants species during
different season were as follows-
A. Pre-monsoon season
During Pre-monsoon season the ten top ranking food plant species of Asian elephant
were- Saccharum elephantium (7.48 %), Erianthus ravennae (7.16 %), Vetiveria zizanioides
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(6.68 %), Butea parviflora (4.88 %), Vitis planicaulis (4.26 %), Mikania micrantha (3.48
%), Ophiouros megaphyllus (3.14 %), Themeda villosa (3.05 %), Phragmites karka (2.84
%), Arundo donax (2.81 %)�in Manas National Park (Table 8.6). These top ten ranking food
plant species of Asian elephant were followed by feeding on other species described in
Table 8.6.
B. Monsoon season
The ten top ranking food plant species of Asian elephant during the monsoon season
were -Saccharum elephantium (7.61 %), Erianthus ravennae (7.51 %), Vetiveria zizanioides
(6.79 %), Butea parviflora (5.38 %), Vitis planicaulis (4.2 %), Mikania micrantha (3.67 %),
Arundo donax (2.86 %), Eleusine indica (2.86 %), Themeda villosa (2.8 %) and Phragmites
karka (2.78 %) in Manas National Park (Table 8.6). These top ten ranking food plant species
of Asian elephant were followed by feeding on other species described in Table 8.6.
C. Retreating Monsoon Season
The ten top ranking food plant species of Asian elephant during the retreating
monsoon were - Saccharum elephantium (9.96 %), Erianthus ravennae (5.53 %),
Phragmites karka (5.39 %), Butea parviflora (4.84 %), Saccharum spontaneum (4.6 %),
Vetiveria zizanioides (4.48 %), lmperata cylindrica (4.4 %), Vitis planicaulis (3.91 %),
Mikania micrantha (3.47 %) and Ophiouros megaphyllus (2.94 %) season in Manas
National Park (Table 8.6). These top ten ranking food plant species of Asian elephant were
followed by feeding on other species described in Table 8.6.
D. Winter Season
The ten top ranking food plant species of Asian elephant during the winter season
were- Saccharum elephantium (10.19 %), Erianthus ravennae (9.68 %), Vetiveria
zizanioides (7.64 %), Butea parviflora (6.38 %), Vitis planicaulis (5.3 %), Mikania
micrantha (4.53 %), Phragmites karka (3.48 %), Arundo donax (3.44 %), Themeda villosa
(3.41 %) and lmperata cylindrica (2.52 %) in Manas National Park (Table 8.6). These top
ten ranking food plant species of Asian elephant were followed by feeding on other species
described in Table 8.6.
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Table 8.6 Showing the feeding frequency on different food plant species by Asian elephant
in Manas National Park.
Sl.
No
Plant
Type
Family Scientific name Seasonal feeding
frequency in %
Annual
feeding
(%) PM M RTM WIN
1 G Poaceae Saccharum
elephantium
7.48 7.61 9.96 10.19 8.81
2 G Poaceae Erianthus ravennae 7.16 7.51 5.53 9.68 7.47
3 G Poaceae Vetiveria zizanioides 6.68 6.79 4.48 7.64 6.4
4 Cl Papilionaceae Butea parviflora 4.88 5.38 4.84 6.38 5.37
5 Cl Vitaceae Vitis planicaulis 4.26 4.2 3.91 5.3 4.42
6 Cl Asteraceae Mikania micrantha 3.48 3.67 3.47 4.53 3.79
7 G Poaceae Phragmites karka 2.84 2.78 5.39 3.48 3.62
8 G Poaceae Themeda villosa 3.05 2.8 2.56 3.41 2.96
9 G Poaceae lmperata cylindrica 2.07 2.1 4.4 2.52 2.77
10 G Poaceae Arundo donax 2.81 2.86 0.71 3.44 2.46
11 G Poaceae Saccharum
spontaneum
1.23 0.76 4.6 1.32 1.98
12 G Poaceae Hymenachne
acutigluma
2.49 2.24 2.56 0 1.82
13 G Poaceae Ophiouros
megaphyllus
3.14 0 2.94 0 1.52
14 Cl Acanthaceae Andrographis
paniculata
1.23 1.29 1.9 1.57 1.5
15 T Bombacaceae Bombax ceiba 1.3 1.38 1.63 1.61 1.48
16 G Poaceae Leersia hexandra 1.86 1.94 2.05 0 1.46
17 Cl Acanthaceae Eclobium linneanum 1.15 1.2 1.85 1.48 1.42
18 St Rhamnaceae Ziziphus mauritiana 1.09 1.16 1.84 1.43 1.38
19 St Rhamnaceae Ziziphus rugosa 1.08 1.13 1.77 1.47 1.36
20 G Zingiberaceae Alpinia nigra 1.15 0.98 1.86 1.42 1.35
21 T Sterculiaceae Sterculia villosa 1.2 1.27 1.46 1.45 1.34
22 G Poaceae Arudinella
brasiliensis
1.22 1.05 1.64 1.35 1.32
23 G Poaceae Saccharum procerum 1.27 1.25 1.14 1.49 1.29
24 G Poaceae Eleusine indica 1.14 2.86 0.71 0 1.18
25 G Poaceae Arundinella
benghalensis
1.3 1.38 0 1.61 1.07
26 G Poaceae Hemarthria
compressa
1.3 1.36 0 1.61 1.07
27 G Andropogaceae Andropogon 1.15 1.2 1.85 0 1.05
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aciculatus
28 G Poaceae Agrosti procera 1.27 1.25 0 1.49 1
29 G Poaceae Panicum ciliara 1.2 1.27 1.46 0 0.98
30 G Poaceae Setaria biflora 1.22 1.05 1.64 0 0.98
31 G Cyperaceae Cyperus pilosus 1.09 1.16 0 1.43 0.92
32 G Poaceae Panicum pumilum 1.26 0.84 0 1.45 0.89
33 G Poaceae Panicum acresus 1.05 1.03 0 1.29 0.84
34 G Poaceae Cynosurus indicus 0.71 0.71 0.84 0.89 0.79
35 G Poaceae Narenga
pophyrocoma
0.66 0.68 0.79 0.82 0.74
36 G Poaceae Panicum pumifolia 1.01 0.95 0.84 0 0.7
37 G Poaceae Saccharum
arundinaceum
1.23 1.29 0 0 0.63
38 G Poaceae Oplismenus
burmannii
1.09 0.92 0.41 0 0.6
39 T Lacythidaceae Careya arborea 0 0.71 0.79 0.83 0.58
40 G Poaceae Panicum walense 0.71 0.71 0 0.89 0.58
41 G Poaceae Millium compressus 1.08 1.13 0 0 0.55
42 T Lythraceae Lagerstroemia
parviflora
0.63 0 0.73 0.78 0.54
43 T Caesalpiniaceae Bauhinia acuminata 0.48 0.49 0.56 0.58 0.53
44 G Poaceae Panicum palvilum 0.66 0.68 0.79 0 0.53
45 T Lauraceae Phoebe paniculata 0.64 0.67 0.76 0 0.52
46 T Caesalpiniaceae Bauhinia variagata 0.5 0.48 0.55 0.57 0.52
47 T Caesalpiniaceae Bauhinia purpurea 0.43 0.42 0.67 0.5 0.5
48 G Poaceae Panicum crusgalii 0.6 0.64 0 0.73 0.49
49 G Cyperaceae Scirpus articulatus 0.57 0 0.67 0.7 0.48
50 G Poaceae Themeda
arundinaceae
0.44 0.44 0.5 0.51 0.47
51 G Poaceae Themeda caudata 0.43 0.43 0.49 0.54 0.47
52 G Poaceae Panicum flavidum 0.57 0.6 0.71 0 0.47
53 G Tamaricaceae Tamarix dioca 0 0.56 0.68 0.66 0.47
54 G Cyperaceae Cyperus diffusus 0 0.55 0.67 0.66 0.47
55 G Poaceae Cymbopogon citratus 0.43 0.44 0.42 0.49 0.44
56 G Poaceae Cymbopogon nardus 0.55 0.55 0 0.65 0.44
57 T Papilionaceae Dalbergia sissoo 0.39 0.41 0.42 0.47 0.42
58 G Polygonaceae Polygonum
hydropiper
0.76 0.71 0.2 0 0.42
59 T Verbenaceae Premna bengalensis 0.5 0.53 0.63 0 0.41
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60 G Poaceae Schizostachyum
dwlooa
0.36 0.34 0.38 0.45 0.38
61 G Poaceae Dendrocalamus
hamiltonii
0.32 0.36 0.39 0.38 0.36
62 T Dilleniaceae Dillenia indica 0.43 0.43 0 0.54 0.35
63 G Poaceae Cynodon dactylon 0.33 0.34 0.34 0.38 0.35
64 G Poaceae Saccharum munja 0.44 0.44 0.5 0 0.34
65 G Cyperaceae Cyperus diformis 0.42 0.43 0 0.52 0.34
66 G Poaceae Dendrocalamus
longispathes
0.29 0.34 0.41 0.33 0.34
67 T Sterculiaceae Abroma augusta 0.43 0.43 0.42 0 0.32
68 T Mimosaceae Acacia catechu 0.29 0.28 0.28 0.34 0.3
69 T Euphorbiaceae Bischofia javanica 0.36 0.39 0 0.42 0.29
70 G Poaceae Hymenachne
assamica
0.29 0.28 0.28 0.32 0.29
71 G Poaceae Digitaria longifolia 0.38 0 0.38 0.42 0.29
72 T Verbenaceae Gmelina arborea 0.33 0 0.38 0.38 0.27
73 T Lauraceae Litsea monopetala 0.36 0 0.33 0.41 0.27
74 G Poaceae Cyrtococcum
accrescens
0.36 0.34 0.38 0 0.27
75 G Poaceae Cymbopogon
aciculatus
0.29 0.34 0.41 0 0.26
76 T Moraceae Ficus benghalensis 0 0.28 0.28 0.34 0.22
77 G Cyperaceae Cyperus cyperoides 0.29 0.28 0.28 0 0.21
78 G Cyperaceae Cyperus digitatus 0 0.21 0.26 0.25 0.18
79 G Cyperaceae Cyperus kyllingia 0 0.68 0 0 0.17
80 G Poaceae Oxytenanthera
albociliata
0.22 0.21 0 0.25 0.17
81 T Moraceae Ficus glomerata 0.17 0.14 0.14 0.19 0.16
82 T Lauraceae Litsea salicifolia 0.14 0.16 0.16 0.17 0.16
83 T Moraceae Ficus religiosa 0.17 0.14 0.13 0.17 0.15
84 T Myrtaceae Syzigium oblatum 0 0.14 0.22 0.17 0.13
85 G Poaceae Digitaria pruriens 0 0 0.26 0.26 0.13
86 T Bixaceae Bixa orellana 0.12 0.11 0.1 0.14 0.12
87 T Myrtaceae Syzigium cumini 0.13 0 0.21 0.15 0.12
88 T Moraceae Ficus benjamina 0.14 0.13 0.21 0 0.12
89 T Meliaceae Toona ciliata 0.18 0.14 0 0.18 0.12
90 T Papilionaceae Erythrina indica 0.15 0.14 0 0.15 0.11
91 G Zingiberaceae Curcuma aromatica 0.17 0.14 0.14 0 0.11
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92 G Cyperaceae Cyperus halpan 0 0.18 0.25 0 0.11
93 T Combretaceae Terminalia bellirica 0 0.11 0.1 0.18 0.1
94 T Dilleniaceae Dillenia pentagyna 0 0.12 0.12 0.14 0.1
95 T Euphorbiaceae Phyllanthus debilis 0 0.11 0.1 0.14 0.09
96 T Anacardiaceae Linnea grandis 0 0.12 0.12 0.14 0.09
97 T Lythraceae Albizia procera 0 0.1 0.09 0.17 0.09
98 T Mimosaceae Lagerstroemia
reginae
0.34 0 0 0 0.09
99 T Moraceae Streblus asper 0.12 0.11 0.1 0 0.08
100 T Combretaceae Terminalia arjuna 0.08 0 0.18 0.07 0.08
101 T Mimosaceae Albizia odoratissima 0.11 0.11 0 0.12 0.08
102 T Dipterocarpaceae Shorea robusta 0.11 0.1 0.09 0 0.08
103 T Rutaceae Aegle marmelos 0 0.1 0.09 0.12 0.08
104 Cl Mimosaceae Mimosa himalayana 0 0.09 0.08 0.12 0.07
105 G Cyperaceae Cyperus iria 0.14 0.16 0 0 0.07
106 Sh Leeaceae Leea aequata 0.08 0.08 0.08 0 0.06
107 Sh Leeaceae Leea asiatica 0.08 0.07 0 0.09 0.06
108 Sh Leeaceae Leea alata 0.12 0.11 0 0 0.06
109 St Papilionaceae Flemingia
strobilifera
0 0.07 0.05 0.07 0.05
110 H Mimosaceae Mimosa pudica 0 0.06 0.05 0.06 0.04
111 H Portulacaceae Portulaca oleraceae 0.05 0.05 0 0.06 0.04
112 H Scrophulariaceae Lindernia crustacea 0 0 0 0 0
PM-Pre-monsoon; M= Monsoon; RTM-Retreating Monsoon; WIN= Winter
T= tree; St= Short tree; Sh= Shrubs; Cl= Climbers; H= Herbs
8.4.6 Food Selectivity
Study revealed that, Asian elephant has showed different selectivity for different
species of plants, while feeding in Manas National Park. The selectivity index were as
follows-
8.4.6.1 Grass Selectivity
From the relative dominance of the food plant species and relative feeding
frequency, the selectivity index were calculated and it was found that, Asian elephant has
strong selection for 25 grass species (R>1) (Table 8.7). The highly selected species were -
Vetiveria zizanioides (2.08), Hemarthria compressa (1.83), Agrosti procera (1.72), Setaria
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biflora (1.69), Panicum ciliara (1.67), Cyperus diffusus (1.61), Panicum pumilum (1.57),
Panicum acresus (1.5), Phragmites karka (1.48), Leersia hexandra (1.46), Hymenachne
acutigluma (1.45), Cynosurus indicus (1.44), Cyperus pilosus (1.43), Ophiouros
megaphyllus (1.36), Andropogon aciculatus (1.27), Narenga pophyrocoma (1.25), Panicum
pumifolia (1.24), Themeda villosa (1.18), Arundinella benghalensis (1.18), Digitaria
longifolia (1.16), Panicum walense (1.07), Oplismenus burmannii (1.04), Saccharum
procerum (1.03), Arundo donax (1.02), Cymbopogon nardus (1.01). There were 35 grass
species (R<1), which were eaten by Asian elephant in Manas National Park due to
availability of these food items. These were - Dendrocalamus hamiltonii (0.96), Tamarix
dioca (0.96), Scirpus articulatus (0.95), Themeda arundinaceae (0.94), Panicum crusgalii
(0.94), Panicum palvilum (0.93), Dendrocalamus longispathes (0.93), Themeda caudata
(0.93), Polygonum hydropiper (0.92), Cynodon dactylon (0.9), Erianthus ravennae (0.9),
Panicum flavidum (0.89), Cymbopogon citratus (0.89), Eleusine indica (0.88), Millium
compressus (0.87), Saccharum elephantium (0.85), Schizostachyum dwlooa (0.85),
Hymenachne assamica (0.8), Arudinella brasiliensis (0.8), Saccharum spontaneum (0.76),
Cyperus diformis (0.75), Saccharum munga (0.68), Saccharum arundinaceum (0.66),
Cyperus cyperoides (0.66), Alpinia nigra (0.62), Cymbopogon aciculatus (0.6), Digitaria
pruriens (0.58), Cyperus digitatus (0.58), Oxytenanthera albociliata (0.57), Cyrtococcum
accrescens (0.56), Cyperus kyllingia (0.56), lmperata cylindrica (0.47), Cyperus halpan
(0.38), Curcuma aromatica (0.35) and Cyperus iria (0.26) (Table 8.7).
8.4.6.2 Short tree, shrubs, climbers and herbs selectivity
The present study revealed that, Asian elephant has strong selection against 5 species
of short tree, shrubs, climbers, herbs (R>1) (Table 8.7). Those highly selected species were -
Vitis planicaulis (7.36), Butea parviflora (4.59), Ziziphus rugosa (1.11), Ziziphus mauritiana
(1.09) and Andrographis paniculata (1.01). There were 10 species (R<1) of these types,
which were eaten by Asian elephant in Manas National Park due to availability of these food
items. These were the Eclobium linneanum (0.97), Mikania micrantha (0.73), Flemingia
strobilifera (0.04), Portulaca oleraceae (0.04), Mimosa himalayana (0.03), Mimosa pudica
(0.02), Leea alata (0.01), Leea aequata (0.01), Leea asiatica (0.01) and Lindernia crustacea
(0.0005) (Table 8.7).
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8.4.6.3 Trees selectivity
The present study revealed that, Asian elephant has a strong selection against 24 tree
species (R>1) (Table 8.7). These highly selected species were - Dalbergia sissoo (25.3),
Shorea robusta (14.57), Bauhinia acuminata (11.85), Sterculia villosa (10.69), Aegle
marmelos (9.07), Acacia catechu (6.93), Dillenia indica (5.35), Albizia odoratissima (3.48),
Abroma augusta (2.86), Bauhinia purpurea (2.83), Erythrina indica (2.81), Bixa orellana
(2.66), Linnea grandis (2.48), Bischofia javanica (2.45), Ficus glomerata (2.41), Terminalia
arjuna (2.3), Bauhinia variagata (2.3), Phoebe paniculata (2.26), Careya arborea (1.86),
Ficus benghalensis (1.57), Ficus religiosa (1.28), Ficus benjamina (1.16), Litsea
monopetala (1.05) and Litsea salicifolia (1.01) (Table 8.7).
There were 13 tree species (R<1) eaten by Asian elephant due to availability in
Manas National Park (Table 8.7). They were- Syzigium oblatum (0.93), Toona ciliata (0.87),
Bombax ceiba (0.79), Lagerstroemia parviflora (0.78), Premna bengalensis (0.73),
Terminalia bellirica (0.68), Gmelina arborea (0.63), Syzigium cumini (0.63), Albizia
procera (0.55), Phyllanthus debilis (0.26), Streblus asper (0.2), Lagerstroemia reginae
(0.17) and Dillenia pentagyna (0.06) (Table 8.7).
Table 8.7 Showing the selectivity index of Asian elephant for different food plants (a)
Grasses, (b) short trees, shrubs, climbers, herbs and (c) trees in Manas National Park.
Sl. No. Family Scientific Name Relative
dominance
Feeding
records
(%)
Selec
-tivity
( R )
a. Selectivity index of Grass
1 Poaceae Vetiveria zizanioides 4.44 9.23 2.08
2 Poaceae Hemarthria compressa 0.84 1.54 1.83
3 Poaceae Agrosti procera 0.84 1.45 1.72
4 Poaceae Setaria biflora 0.83 1.41 1.69
5 Poaceae Panicum ciliara 0.85 1.42 1.67
6 Cyperaceae Cyperus diffusus 0.42 0.68 1.61
7 Poaceae Panicum pumilum 0.82 1.28 1.57
8 Poaceae Panicum acresus 0.81 1.22 1.5
9 Poaceae Phragmites karka 3.54 5.23 1.48
10 Poaceae Leersia hexandra 1.45 2.11 1.46
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11 Poaceae Hymenachne
acutigluma
1.81 2.63 1.45
12 Poaceae Cynosurus indicus 0.79 1.13 1.44
13 Cyperaceae Cyperus pilosus 0.93 1.33 1.43
14 Poaceae Ophiouros megaphyllus 1.61 2.19 1.36
15 Andropogaceae Andropogon aciculatus 1.2 1.52 1.27
16 Poaceae Narenga pophyrocoma 0.85 1.06 1.25
17 Poaceae Panicum pumifolia 0.81 1.01 1.24
18 Poaceae Themeda villosa 3.62 4.26 1.18
19 Poaceae Arundinella
benghalensis
1.31 1.55 1.18
20 Poaceae Digitaria longifolia 0.36 0.42 1.16
21 Poaceae Panicum walense 0.78 0.83 1.07
22 Poaceae Oplismenus burmannii 0.84 0.87 1.04
23 Poaceae Saccharum procerum 1.8 1.86 1.03
24 Poaceae Arundo donax 3.47 3.54 1.02
25 Poaceae Cymobopogon nardus 0.62 0.63 1.01
26 Poaceae Dendrocalamus
hamiltonii
0.55 0.53 0.96
27 Tamaricaceae Tamarix dioca 0.72 0.68 0.96
28 Cyperaceae Scirpus articulatus 0.74 0.7 0.95
29 Poaceae Themeda arundinaceae 0.72 0.68 0.94
30 Poaceae Panicum crusgalii 0.75 0.71 0.94
31 Poaceae Panicum palvilum 0.83 0.77 0.93
32 Poaceae Dendrocalamus
longispathes
0.53 0.49 0.93
33 Poaceae Themeda caudata 0.73 0.68 0.93
34 Polygonaceae Polygonum hydropiper 0.65 0.6 0.92
35 Poaceae Cynodon dactylon 0.56 0.5 0.9
36 Poaceae Erianthus ravennae 12.02 10.77 0.9
37 Poaceae Panicum flavidum 0.76 0.68 0.89
38 Poaceae Cymbopogon citratus 0.72 0.64 0.89
39 Poaceae Eleusine indica 1.93 1.7 0.88
40 Poaceae Millium compressus 0.91 0.8 0.87
41 Poaceae Saccharum elephantium 14.88 12.7 0.85
42 Poaceae Schizostachyum dwlooa 0.65 0.55 0.85
43 Poaceae Hymenachne assamica 0.52 0.42 0.8
44 Poaceae Arudinella brasiliensis 2.38 1.9 0.8
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45 Poaceae Saccharum spontaneum 3.77 2.85 0.76
46 Cyperaceae Cyperus diformis 0.66 0.49 0.75
47 Poaceae Saccharum munja 0.73 0.5 0.68
48 Poaceae Saccharum
arundinaceum
1.37 0.91 0.66
49 Cyperaceae Cyperus cyperoides 0.46 0.3 0.66
50 Zingiberaceae Alpinia nigra 3.14 1.95 0.62
51 Poaceae Cymobopogon
aciculatus
0.63 0.38 0.6
52 Poaceae Digitaria pruriens 0.32 0.19 0.58
53 Cyperaceae Cyperus digitatus 0.45 0.26 0.58
54 Poaceae Oxytenanthera
albociliata
0.43 0.25 0.57
55 Poaceae Cyrtococcum
accrescens
0.7 0.39 0.56
56 Cyperaceae Cyperus kyllingia 0.44 0.24 0.56
57 Poaceae lmperata cylindrica 8.43 4 0.47
58 Cyperaceae Cyperus halpan 0.41 0.16 0.38
59 Zingiberaceae Curcuma aromatica 0.47 0.17 0.35
60 Cyperaceae Cyperus iria 0.42 0.11 0.26
b. Selectivity index of short trees, shrubs, climbers, herbs
1 Vitaceae Vitis planicaulis 0.6 4.42 7.36
2 Papilionaceae Butea parviflora 1.17 5.37 4.59
3 Rhamnaceae Ziziphus rugosa 1.23 1.36 1.11
4 Rhamnaceae Ziziphus mauritiana 1.26 1.38 1.09
5 Acanthaceae Andrographis
paniculata
1.48 1.5 1.01
6 Acanthaceae Eclobium linneanum 1.47 1.42 0.97
7 Asteraceae Mikania micrantha 5.22 3.79 0.73
8 Papilionaceae Flemingia strobilifera 1.13 0.05 0.04
9 Portulacaceae Portulaca oleraceae 1.06 0.04 0.04
10 Mimosaceae Mimosa himalayana 2.44 0.07 0.03
11 Mimosaceae Mimosa pudica 2.26 0.04 0.02
12 Leeaceae Leea alata 6.29 0.06 0.01
13 Leeaceae Leea aequata 6.5 0.06 0.01
14 Leeaceae Leea asiatica 7.08 0.06 0.01
15 Scrophulariaceae Lindernia crustacea 1.01 0 0
c. Selectivity index of trees
1 Papilionaceae Dalbergia sissoo 0.18 4.55 25.3
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2 Dipterocarpaceae Shorea robusta 0.05 0.68 14.57
3 Caesalpiniaceae Bauhinia acuminata 0.4 4.78 11.85
4 Sterculiaceae Sterculia villosa 1.14 12.18 10.69
5 Rutaceae Aegle marmelos 0.08 0.7 9.07
6 Mimosaceae Acacia catechu 0.55 3.83 6.93
7 Dilleniaceae Dillenia indica 0.59 3.17 5.35
8 Mimosaceae Albizia odoratissima 0.22 0.76 3.48
9 Sterculiaceae Abroma augusta 0.71 2.03 2.86
10 Caesalpiniaceae Bauhinia purpurea 0.95 2.69 2.83
11 Papilionaceae Erythrina indica 0.4 1.12 2.81
12 Bixaceae Bixa orellana 0.93 2.47 2.66
13 Anacardiaceae Linnea grandis 0.34 0.85 2.48
14 Euphorbiaceae Bischofia javanica 1.08 2.64 2.45
15 Moraceae Ficus glomerata 1.21 2.91 2.41
16 Combretaceae Terminalia arjuna 0.33 0.75 2.3
17 Caesalpiniaceae Bauhinia variagata 2.07 4.75 2.3
18 Lauraceae Phoebe paniculata 2.08 4.7 2.26
19 Lacythidaceae Careya arborea 2.83 5.27 1.86
20 Moraceae Ficus benghalensis 0.89 1.41 1.57
21 Moraceae Ficus religiosa 1.07 1.37 1.28
22 Moraceae Ficus benjamina 0.97 1.12 1.16
23 Lauraceae Litsea monopetala 0.83 0.87 1.05
24 Lauraceae Litsea salicifolia 1.46 1.47 1.01
25 Myrtaceae Syzigium oblatum 1.16 1.07 0.93
26 Meliaceae Toona ciliata 1.24 1.08 0.87
27 Bombacaceae Bombax ceiba 16.9 13.41 0.79
28 Lythraceae Lagerstroemia
parviflora
6.18 4.85 0.78
29 Verbenaceae Premna bengalensis 5.13 3.76 0.73
30 Combretaceae Terminalia bellirica 1.46 1 0.68
31 Verbenaceae Gmelina arborea 3.92 2.48 0.63
32 Myrtaceae Syzigium cumini 1.93 1.21 0.63
33 Mimosaceae Albizia procera 1.49 0.82 0.55
34 Euphorbiaceae Phyllanthus debilis 3.06 0.81 0.26
35 Moraceae Streblus asper 3.86 0.76 0.2
36 Lythraceae Lagerstroemia reginae 4.55 0.78 0.17
37 Dilleniaceae Dillenia pentagyna 14.47 0.88 0.06
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8.4.7 Staple food
The analysis of staple food revealed that, altogether 40 plant species (Table 8.8) were
selected by Asian elephant as their regular food item. These 40 plant species constituted
71.41 % of the total selected annual feeding budget and were referred as staple food of
Asian elephant. Study showed that, 21 grass species contributed the major portion of Asian
elephant annual food budget (45.06 %) and eight short trees, shrubs, climbers, herbs
contributed 20.66 % of total annual food budget. Whereas, 11 species of plants contributed
minimum of 5.69 % of total Asian elephant annual budget as staple food (Table 8.8; Table
8.9).
Analysis of paired sample t-test showed that, there was no significant difference
between the feeding frequency of Asian elephant on different staple food plant species in
different season of the year (P > 0.05) (Table 8.10).
Table 8.8 Showing the staple food of Asian elephant in Manas National Park.
Sl.
No.
Plant
Type
Family Scientific name % of Feeding
PM M RTM WIN
Grasses
1 G Poaceae Saccharum
elephantium
7.48 7.61 9.96 10.19
2 G Poaceae Erianthus ravennae 7.16 7.51 5.53 9.68
3 G Poaceae lmperata cylindrica 2.07 2.1 4.4 2.52
4 G Poaceae Vetiveria
zizanioides
6.68 6.79 4.48 7.64
5 G Poaceae Saccharum
spontaneum
1.23 0.76 4.6 1.32
6 G Poaceae Themeda villosa 3.05 2.8 2.56 3.41
7 G Poaceae Phragmites karka 2.84 2.78 5.39 3.48
8 G Poaceae Arundo donax 2.81 2.86 0.71 3.44
9 G Zingiberaceae Alpinia nigra 1.15 0.98 1.86 1.42
10 G Poaceae Arudinella
brasiliensis
1.22 1.05 1.64 1.35
11 G Poaceae Saccharum
procerum
1.27 1.25 1.14 1.49
12 G Poaceae Cynosurus indicus 0.71 0.71 0.84 0.89
13 G Poaceae Narenga
pophyrocoma
0.66 0.68 0.79 0.82
14 G Poaceae Themeda 0.44 0.44 0.5 0.51
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arundinaceae
15 G Poaceae Themeda caudata 0.43 0.43 0.49 0.54
16 G Poaceae Cymbopogon
citratus
0.43 0.44 0.42 0.49
17 G Poaceae Schizostachyum
dwlooa
0.36 0.34 0.38 0.45
18 G Poaceae Dendrocalamus
hamiltonii
0.32 0.36 0.39 0.38
19 G Poaceae Cynodon dactylon 0.33 0.34 0.34 0.38
20 G Poaceae Dendrocalamus
longispathes
0.29 0.34 0.41 0.33
21 G Poaceae Hymenachne
assamica
0.29 0.28 0.28 0.32
Short trees, shrubs, climbers, herbs
1 Cl Papilionaceae Butea parviflora 4.88 5.38 4.84 6.38
2 Cl Vitaceae Vitis planicaulis 4.26 4.2 3.91 5.3
3 Cl Asteraceae Mikania micrantha 3.48 3.67 3.47 4.53
4 Cl Acanthaceae Andrographis
paniculata
1.23 1.29 1.9 1.57
5 Cl Acanthaceae Eclobium
linneanum
1.15 1.2 1.85 1.48
6 St Rhamnaceae Ziziphus mauritiana 1.09 1.16 1.84 1.43
7 St Rhamnaceae Ziziphus rugosa 1.08 1.13 1.77 1.47
8 Cl Acanthaceae Eclobium
linneanum
1.15 1.2 1.85 1.48
Trees
1 T Bombacaceae Bombax ceiba 1.3 1.38 1.63 1.61
2 T Sterculiaceae Sterculia villosa 1.2 1.27 1.46 1.45
3 T Caesalpiniaceae Bauhinia variagata 0.5 0.48 0.55 0.57
4 T Caesalpiniaceae Bauhinia
acuminata
0.48 0.49 0.56 0.58
5 T Papilionaceae Dalbergia sissoo 0.39 0.41 0.42 0.47
6 T Caesalpiniaceae Bauhinia purpurea 0.43 0.42 0.67 0.5
7 T Mimosaceae Acacia catechu 0.29 0.28 0.28 0.34
8 T Moraceae Ficus glomerata 0.17 0.14 0.14 0.19
9 T Lauraceae Litsea salicifolia 0.14 0.16 0.16 0.17
10 T Moraceae Ficus religiosa 0.17 0.14 0.13 0.17
11 T Bixaceae Bixa orellana 0.12 0.11 0.1 0.14
PM-Pre-monsoon; M= Monsoon; RTM-Retreating Monsoon; WIN=Winter
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Table 8.9 Relative use of staple food by Asian elephant in Manas National Park.
Type of Plants Staple food plant
species
Proportional use of staple food
Number Proportional
use
PM M RTM WIN
Grasses 21 60.07 41.22 40.85 47.11 51.05
Short trees, shrubs, climbers,
herbs 8
27.54 18.32 19.23 21.43 23.64
Trees 11 7.59 5.19 5.28 6.1 6.19
Total 40 95.2 64.73 65.36 74.64 80.88
Table 8.10 Showing the analysis of paired samples t-test between the feeding frequencies of
staple food plant species by Asian elephant in different seasons of the year during study
period in MNP.
Paired Samples Test
Pair Paired Differences
Mean ��SD ��SE 95%
Confidence
Interval of the
Difference
t df Sig.
(2-
tailed)
Lower Upper
Pair 1 PM - M -0.31 0.57 0.28 -1.22 0.59 -1.11 3 0.35
Pair 2 M - RTM -4.64 3.86 1.93 -10.78 1.50 -2.40 3 0.10
Pair 3 RTM - WIN -3.12 2.61 1.30 -7.3 1.0 -2.39 3 0.10
Pair 4 PM - WIN -8.08 6.48 3.24 -18.4 2.2 -2.49 3 0.09
PM=Pre-monsoon; M= Monsoon; RTM= Retreating monsoon; WIN= Winter.
8.4.8 Dietary spectrum
During the present study on feeding frequency of different food plants by Asian
elephant it was revealed that, Asian elephant has distinct food spectrum in Manas National
Park. The study revealed that, ten top ranking food plant species of Asian elephant
contributed 48.06 % of the total annual budget, whereas the twenty top ranking food plant
species has contributed total of 63.33 % in total annual food budget of Asian elephant in
Manas National Park. Among the twenty top ranking food plant species- 12 were grass, five
were climbers, two were short trees and single tree species. It was clearly revealed from the
present study that, major portion of Asian elephant diet was contributed by grasses in Manas
National Park (Figure 8.2).
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Figure 8.2 Dietary spectrum of Asian elephant in Manas National Park.
8.4.9 Cultivated crop as food
During the present study it was found that, Asian elephants raid the crops and other
plants in the fringe village areas. There were altogether 21 crops and other plant species,
which were eaten by Asian elephant (Table 8.11). No quantitative analysis of these crops
and plants were made during the present study. Because, Asian elephant mostly consumed
those plant species during night hours.
Table 8.11 Cultivated crop and vegetable species eaten by Asian elephant in the fringe areas
of Manas National Park.
Sl. No. Type Family Scientific name Vernacular
Name
1 G Bromeliaceae Ananas comosus (L) Merr Anarsh
2 Cl Convolvulaceae Ipomea batatus (L.)Lamk Mithaalu
3 Sh Euphorbiaceae Manihot esculenta Simalu Alu
4 T Moraceae Artocarpus heterophyllus Kathal
5 G Musaceae Musa balbisiana Colla Vimkol
6 G Musaceae Musa Champa Hort Senisampa Kol
7 G Musaceae Musa chinensis Sweet. Jahaji Kol
8 G Musaceae Musa paradisiaca L. Kas Kol
9 G Musaceae Musa sapientum L. Monohar Kol
10 G Musaceae Musa velutina Malvug Kol
8.8
1 16.2
8
22
.68
28
.04
32.4
6
36
.25
39.8
7
42.8
3
45
.6
48
.06
50
.04
51.8
6
53
.38
54
.87
56.3
5
57.8
1
59
.24
60
.61
61
.98
63.3
3
100
0
20
40
60
80
100
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 112
Die
tary
sp
ectr
um
(%
)
Number of food plant
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11 H Papilionaceae Pisum sativum L. Motor Mah
12 H Papilionaceae Vigna mungo (L.) Happer Matimah
13 H Papilionaceae Vigna radiate (L.) Wilez Magumah
14 G Poaceae Oryza sativa L. Dhan
15 G Poaceae Oxytenanthera albociliata
Munro
Jatibah
16 G Poaceae Saccharum officinarum L. Kuhiar
17 G Poaceae Triticum aestivum L. Ghehu
18 G Poaceae Zea mays L. Makoi
19 Sh Rosaceae Pyrus communis L. Naspati
20 Palm Arecaceae Areca catechu L. Tamul
21 Palm Arecaceae Cocos nucifera L Narikol
8.4.10 Geophagy
Asian elephant were found to visit regularly six geophagy sites in Manas National
Park. These geophagy sites were- Giati, Haru Giati Garuchara, Rabang, Dwimari and
Jajanga.
8.4.10.1 Nutrient contents in geophagy soil samples
The mean value of P2O5 content in the topsoil sample was 25.19 mg kg-1
± 1.96 SE
(n=6); whereas, the P2O5 content in the soil samples collected from the soil licking sites of
Asian elephant in Manas National Park was 62.63 mg kg-1
± 3.93 SE(n=6) (Table-8.12,
Table-8.13, Table-8.14). The mean value of Se content in the topsoil sample was found to be
0.45 mg kg-1
± 0.09 SE (n=6); whereas, the mean value of Se content in soil samples
collected from the soil licking sites of Asian elephant in Manas National Park was 0.93 mg
kg-1
± 0.12 SE(n=6) (Table-8.12, Table-8.13, Table-8.14). The mean value of Mn content in
the topsoil sample was found to be 1.34 mg kg-1
± 0.16 SE (n=6); whereas, the mean value
of Mn content in the soil samples collected from the soil licking sites of Asian elephant in
Manas National Park was 1.66 mg kg-1
± 0.47 SE (n=6) (Table-8.12, Table-8.13, Table-
8.14). Again, the mean value of Zn content in the topsoil sample was found to be 0.92 mg
kg-1
± 0.17 SE (n=6); whereas, the mean value of Zn content in the soil samples collected
from the soil licking sites of Asian elephant in Manas National Park was 0.91 mg kg-1
± 0.15
SE (n=6) (Table-8.12, Table-8.13, Table-8.14). The mean value of Cu content in the topsoil
sample was found to be 14.83 mg kg-1
± 1.61 SE (n=6); whereas, the mean value of Cu
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content in the soil samples collected from the soil licking sites of Asian elephant in Manas
National Park was 41.04 mg kg-1
± 4.1 SE (n=6) (Table-8.12, Table-8.13, Table-8.14). The
mean value of Mo content in the topsoil sample was found to be 0.95 mg kg-1
± 0.19SE
(n=6); whereas, the mean value of Mo content in the soil samples collected from the soil
licking sites of Asian elephant in Manas National Park was 1.18 mg kg-1
± 0.22 SE (n=6)
(Table-8.12, Table-8.13, Table-8.14). The mean value of B content in the topsoil sample was
found to be 12.39 mg kg-1
± 1.06 SE (n=6); whereas, the mean value of B content in the soil
samples collected from the soil licking sites of Asian elephant in Manas National Park was
13.21 mg kg-1
± 1.17 SE (n=6) (Table-8.12, Table-8.13, Table-8.14). Again, the mean value
of Na content in the topsoil sample was found to be 164.8 mg kg-1
± 2.87 SE (n=6); whereas,
the mean value of Na in the soil samples collected from the soil licking sites of Asian
elephant in Manas National Park was 410.52 mg kg-1
± 63 SE (n=6) (Table-8.12, Table-
8.13, Table-8.14). The mean value of Mg content in the topsoil sample was found to be
412.53 mg kg-1
± 43.42 SE (n=6); whereas, the mean value of Mg content in the soil
samples collected from the soil licking sites of Asian elephant in Manas National Park was
461.58 mg kg-1
± 28.5 SE (n=6) (Table-8.12, Table-8.13, Table-8.14). The mean value of K
content in the topsoil sample was found to be 1161.42 mg kg-1
± 28.23 SE (n=6); whereas,
the mean value of K content in the soil samples collected from the soil licking sites of Asian
elephant in Manas National Park was 2797.25 mg kg-1
± 122.28 SE (n=6) (Table-8.12,
Table-8.13, Table-8.14). The mean value of Ca content in the topsoil sample was found to
be 2452.33 mg kg-1
± 91.21 SE (n=6); whereas, the mean value of Ca content amount in the
soil samples collected from the soil licking sites of Asian elephant in Manas National Park
was 6390.5 mg kg-1
± 338.6 SE (n=6) (Table-8.12, Table-8.13, Table-8.14).
However, none of the nutrients, analysed in different sites of the study area was
consistently enriched relative to the adjacent topsoil, which were not licked by Asian
elephant. But, in all the location of the elephant geophagy sites the analysis of paired sample
t-test showed that, there was a significant difference between the Na content of the topsoil
which were not licked by the Asian elephant with Na content of the soil samples which were
collected from the geophagy sites (t=3.91;P =0.002)(Table 8.15).
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Table 8.12 Showing the nutrient content (mg kg-1
) in the top soil samples collected away
from the licking sites in Manas National Park.
Collection of
Topsoil away
from licking site
No
of
Sam
ples
P2O5
mg
kg-1
Se
mg kg-1
Mn
mg kg-1
Zn
mg kg-1
Cu
mg kg-1
Mo
mg kg-1
B
mg kg-1
Na
mg kg-1
M g
mg kg-1
K
mg kg-1
Ca
mg kg-
1
Dwimari 1 1 40.5 0.18 1.3 0.29 24 0.56 11 156 535 1124 16.18
Dwimari 2 1 37.3 0.24 2.54 0.46 14 0.23 12.2 178 5.24 924 14.91
Rabang 1 1 23 0.1 1.47 0.62 17 0.96 12 173 364 1162 20.09
Rabang 2 1 21.5 0.21 1.69 1.47 14 1.54 14.5 155 396 1245 18.27
Garuchara 1 1 21.5 1.1 1.25 0.12 11 0.45 17.3 175 485 1246 15.38
Garuchara 2 1 23.5 0.92 0.54 1.24 18.4 0.45 16 155 513 1154 13.64
Giati 1 1 24.3 0.67 1.62 1.34 2.6 2.14 9.4 146 321 1248 16.82
Giati 2 1 23.8 0.59 0.65 1.54 11.2 2.14 6.24 162 564 1064 16.03
Haru Giati 1 1 25.2 0.34 1.74 2.12 11 0.74 6 167 357 1208 13.67
Haru Giati 2 1 24.6 0.29 1.52 0.62 15.9 0.67 15 171 421 1124 14.59
Jajanga 1 1 19.8 0.42 0.92 0.71 21.1 0.68 15 165 527 1274 14.42
Jajanga 2 1 17.3 0.34 0.84 0.54 17.6 0.79 14 172 462 1164 13.43
Table 8.13 Showing the nutrient content of the soil samples collected from soil licking sites in
Manas National Park.
Location and
Collection
Site in Salt
licks
No
of
Sam
ples
P2O5
mg kg-1
Se
mg kg-1
Mn
mg kg-1
Zn
mg kg-1
Cu
mg kg-1
Mo
mg kg-1
B
mg kg-1
Na
mg kg-1
M g
mg kg-1
K
mg kg-1
Ca
mg kg-1
Dwimari 1 1 60 0.85 5.6 1.42 54 2.3 8.24 927 576 3705 47.77
Dwimari 2 1 62.8 0.52 4.2 0.65 41 2.14 6.58 813 547 2156 48.57
Rabang 1 1 82.4 0.54 2.34 0.54 34 2.14 17.5 347 564 2674 46.17
Rabang 2 1 86 0.42 1.25 1.16 36.5 1.45 15 338 535 2730 43.44
Garuchara 1 1 52.1 1.7 0.56 0.64 21.5 1.42 16.8 347 516 3156 55.68
Garuchara 2 1 67.8 1.4 0.54 1.92 23.6 0.56 17 338 506 3416 34.53
Giati 1 1 75 1.24 1.25 0.16 56 0.26 14 286 342 2734 39.75
Giati 2 1 68.9 1.37 0.48 0.18 62.5 0.49 11.4 278 324 2641 33.38
Haru
Giati
Haru
Giati
1 1 54.2 0.68 0.48 0.98 24 1.24 14.6 279 365 2649 36.14
2 1 46.2 0.74 1.28 1.54 35 0.85 7.41 269 325 2567 34.55
Jajanga 1 1 46.8 0.94 1.24 0.91 56.2 0.12 18 349 421 2567 35.94
Jajanga 2 1 49.2 0.78 0.64 0.85 48.3 1.14 12 356 517 2572 32.54
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Table 8.14 Showing the mean value of nutrients from the collected soil sample from the top
soil away from the salt licks and from the salt licking sites in Manas National Park.
Soil Samples Mean N Std. Error Mean
Salt Lick-P2O5 62.63 12 3.93
P2O5(Topsoil) 25.19 12 1.96
Salt Lick-Se 0.93 12 0.12
Se(Topsoil) 0.45 12 0.09
Salt Lick-Mn 1.66 12 0.47
Mn(Topsoil) 1.34 12 0.16
Salt Lick-Zn 0.91 12 0.15
Zn (Topsoil) 0.92 12 0.17
Salt Lick-Cu 41.04 12 4.10
Cu (Topsoil) 14.83 12 1.61
Salt Lick-Mo 1.18 12 0.22
Mo (Topsoil) 0.95 12 0.19
Salt Lick-B 13.21 12 1.17
B (Topsoil) 12.39 12 1.06
Salt Lick Na 410.52 12 63.00
Na (Topsoil) 164.80 12 2.87
Salt Lick-M g 461.58 12 28.50
M g (Topsoil) 412.53 12 43.42
Salt Lick -K 2797.25 12 122.28
K (Topsoil) 1161.42 12 28.23
Salt Lick Ca 6390.50 12 338.60
Ca (Topsoil) 2452.33 12 91.21
Table 8.15 Showing the paired samples t-test of the nutrients from the collected soil sample
from the top soil away from the salt licks and from the salt licking sites by Asian elephant in
Manas National Park.
Paired Samples Test
Pair Paired Differences
Mean ��SD ��SE 95% Confidence
Interval of the
Difference
t df Sig.
(2-
tailed)
Lower Upper
Pair 1
Salt Lick-P2O5 -
P2O5(Topsoil)
37.43 14.97 4.32 27.9 46.947 8.66 11 3.048
Pair 2
Salt Lick-Se -
Se(Topsoil)
0.482 0.161 0.05 0.38 0.5843 10.3 11 5.319
Pair 3 Salt Lick-Mn - 0.315 1.46 0.42 -0.6 1.2424 0.75 11 0.470
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Mn(Topsoil)
Pair 4
Salt Lick-Zn -
Zn (Topsoil)
-0.01 0.835 0.24 -0.5 0.5206 -0 11 0.967
Pair 5
Salt Lick-Cu -
Cu (Topsoil)
26.22 15.06 4.35 16.6 35.782 6.03 11 8.540
Pair 6
Salt Lick-Mo -
Mo (Topsoil)
0.23 1.182 0.34 -0.5 0.9812 0.68 11 0.513
Pair 7
Salt Lick-B - B
(Topsoil)
0.82 4.825 1.39 -2.2 3.8856 0.59 11 0.567
Pair 8
Salt Lick Na -
Na (Topsoil)
245.7 217.6 62.8 107 383.95 3.91 11 0.002
Pair 9
Salt Lick-M g -
M g (Topsoil)
49.05 192.7 55.6 -73 171.47 0.88 11 0.396
Pair 10
Salt Lick -K - K
(Topsoil)
1636 408.1 118 1377 1895.1 13.9 11 2.563
Pair 11
Ca - Ca
(Topsoil)
3938 1071 309 3258 4618.5 12.7 11 6.266
8.4.11 Seed dispersal by Asian elephant
There were altogether 26 plant species belonging to 15 families were germinated
from the seed samples obtained from Asian elephant dung in MNP (Figure 8.3; Table 8.16).
Seeds of single species from each of the family Bombacaceae, Combretaceae, Ehretiaceae,
Euphorbiaceae, Lacythidaceae, Rutaceae, Verbenaceae and Vitaceae were germinated from
seeds collected from elephant dung hence, dispersed by the elephant. Seeds of two species
from each the family Dilleniaceae, Mimosaceae, Myrtaceae and Papilionaceae were found to
germinate from the dung of Asian elephant. Again, Seeds of three species from each the
family Lauraceae and Poaceae were germinated from elephant dung. While from the
Moraceae family seeds of four species were germinated from the samples obtained from the
dung of Asian elephant in MNP. Among the seedling germinated in the germination site
most of the seedlings were trees (65 %), which was followed by shrubs (12 %), grass (11%),
climber (8 %) and minimum germination of herbs (4 %).
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Figure 8.3 Saplings germinated from the seeds (Careya arborea) in the Asian elephant dung in MNP.
Table 8.16 The species of plants from MNP that germinated from dung piles of Asian elephant in MNP.
Species Name Family Group of plants
No. ofSeedling
Eleusine indica (L.) Gaert. Poaceae grass 36
Saccharum elephantium Poaceae grass 27
Bombax ceiba Bombacaceae tree 38
Careya arborea Roxb. Lacythidaceae tree 19
Phoebe paniculata Nees. Lauraceae tree 24
Acacia catechu (L.f.) Willd. Mimosaceae tree 43
Dalbergia sissoo Roxb. Papilionaceae tree 38
Dillenia indica L. Dilleniaceae tree 38
Ficus glomerata Roxb. Moraceae tree 30
Ficus religiosa L. Moraceae tree 26
Litsea monopetala (Roxb.) pers Lauraceae tree 17
Litsea salicifolia (Nees) Hook. f. Lauraceae shrub 26
Gmelina arborea Roxb. Verbenaceae tree 33Syzigium oblatum (Roxb.) Wall. Ex A.M.N. & 1. M. Cowan Myrtaceae tree 34
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Phyllanthus debilis Wild. Euphorbiaceae tree 11
Terminalia bellirica (Gaertn.) Roxb. Combretaceae tree 13
Streblus asper Lour. Moraceae tree 6
Mimosa himalayana Gamble. Mimosaceae herb 11
Dillenia pentagyna Dilleniaceae tree 19
Glycosmis arborea (Roxb.) Corr. Rutaceae shrubs 13
Psidium guajava L. Myrtaceae shrubs 10
Ehretia acuminata R. Br. Ehretiaceae tree 7
Artocarpus heterophyllus Lamk. Moraceae tree 9
Butea parviflora Roxb. Papilionaceae climber 3
Vitis planicaulis Hoof.f Vitaceae climber 2
Oryza sps. Poaceae grass 4
8.4.11.1 Proportional Germination of seed
The plant species belonging to Moraceae family was found to be germinated in
maximum proportion of 0.132 from collected seed samples from Asian elephant dung
followed by Lauraceae (0.125), Poaceae (0.125), Dilleniaceae (0.106), Mimosaceae (0.101),
Myrtaceae (0.082), Papilionaceae (0.076), Bombacaceae (0.071), Verbenaceae (0.061),
Lacithidaceae (0.035), Combretaceae (0.024), Rutaceae (0.024), Euphorbiaceae (0.02),
Ehretiaceae (0.013) and Vitaceae (0.004) (Table 8.17).
Table 8.17 Proportional seed germination of seed from the dung sample collected of Asian
elephant.
Family Species Total seedling
Proportional germination
Bombacaceae 1 38 0.071
Combretaceae 1 13 0.024
Dilleniaceae 2 57 0.106
Ehretiaceae 1 7 0.013
Euphorbiaceae 1 11 0.02
Lacithidaceae 1 19 0.035
Lauraceae 3 67 0.125
Mimosaceae 2 54 0.101
Moraceae 4 71 0.132
Myrtaceae 2 44 0.082
Papilionaceae 2 41 0.076
Poaceae 3 67 0.125
Rutaceae 1 13 0.024
Verbenaceae 1 33 0.061
Vitaceae 1 2 0.004
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8.5 Discussion
8.5.1 Food plants
The food spectrum of Asian elephants is 112 food plants species in MNP. More than
half of the food plant species were grasses (60 species). However, the herbs, climbers,
shrubs and tree species also contributed as the food species of Asian elephant in Manas
National Park. The Asian elephant utilizes the grass species as their food in Manas National
Park as the grass species can provide major portion of the daily food budget of Asian
elephant with minimal foraging efforts. Elephant feeds on the grass species during the pre-
monsoon season, 2-3 weeks after the annual burning practice of grassland in Manas National
Park. During that period, elephant feeds on the new sprouts in the grassland areas of the
Manas National Park. Again, the elephant feeds on tree species, during monsoon season
higher than pre-monsoon season, as the grass species no longer remained as quality food for
the elephant. McCullagh (1969) suggested decrease in the digestibility of protein when the
protein content of a food item is low and the fibre content high. Elephants consume more
browse as the quality of abundant items, such as grasses, forbs and climbers declines. Thus
the motivation or "trigger" for crop raiding by elephant during any particular monsoon
season may be decline in the quality of grasses in Manas National Park. They utilize the
climbers, herbs and shrubs during all the seasons of the year. But, they used to feed on the
bark of trees, climbers during the winter and the pre-monsoon season mostly in Manas
National Park.
Seasonally elephant has been using highest number of food plant species during the
monsoon season (101) and lowest during the winter season (80). The availability of the plant
species during the monsoon season has been found high during the monsoon season in
comparison to the winter season. The availability of the quality food during winter has been
found decreasing, which is the cause for lowest food plant species used by Asian elephant
during the season in Manas National Park.
Asian elephants shows, differences in the food spectrum in varied climatic regions.
McKay (1973) has found that, elephant diet in Gal Oya National Park includes 89 plant
species while in Malayan rain forest it was reported to be 390 food plant species (Olivier,
1978a). In the Way Kambas Game Reserve of Sumatra, the elephants feed on 51 plant
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species only (Santiapillai and Suprahman, 1986). Sukumar (1985a) has enumerated 112
plant species constituting elephant diet in south India. Sivaganesan and Bhushan (1986)
have listed 36 plant species in the diet of elephants’ food in Andhra Pradesh. McKay (1973)
recorded that, Asian elephant feeding areas were shifted several times daily and in Sri Lanka
elephants as elephants feed on grasses in open areas during the cooler morning and evening
periods and browse in shaded areas during the hot period of the day. The Asiatic elephant
frequently shifts activities between alluvial grasslands, savanna-scrub, grassy ecotone areas
and forest interiors in daily foraging activities (McKay, Op. cit.; Vancuylenberg, 1977).
Wyatt and Eltringham (1974) reported three peak periods of feeding by elephant during the
24 hour cycle. These were around mid night, early morning and in the afternoon.
In Manas National Park grasses contributed highest (69.35 %) percentage of Asian
elephant food annually. The grass species Saccharum elephantium (8.81%) has been
consumed by the Asian elephant in Manas National Park. Among the top ten food plant
species of Asian elephant seven species are grasses and rest are trees, shrubs, climbers, herbs
etc. Hence, grass plays a major role for Asian elephant food requirement in Manas National
Park despite of presence of highly productive woodland habitat like the semi evergreen
forest. McKay (1971) and Vancuylenberg (1977) have also suggested that, grasses are
preferred food source and comprise a high proportion of the diet when conditions permit.
Olivier (1978a) and Blower (1985) have suggested bamboo as an important food source in
heavily forested habitats where the availability of other grasses is limited, but this
phenomenon has not been observed in Manas National Park.
The Asian elephant of Manas National Park has strong selection for 25 grass species
(R>1); has strong selection for 5 species of short tree, shrubs, climbers, herbs (R>1); strong
selection for 24 tree species (R>1). Although, the major portion of Asian elephant food
budget has been contributed by grass, yet it has strong selection of tree species having
higher selectivity index viz. Dalbergia sissoo (25.3), Shorea robusta (14.57), Bauhinia
acuminata (11.85), Sterculia villosa (10.69), Aegle marmelos (9.07) than the grass species.
But, Asian elephant has consumed mostly grass species as food, owing to the high
availability of grasses and low foraging effort required and hence, they are grazers in Manas
National Park.
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Sivaganesan and Johnsingh (1995) have clearly indicated that, elephants are
predominantly grazers in all the habitats except in degraded areas of thorn forest. More
consumption of grass by elephants in the wet season in deciduous forest areas of Eastern
Ghats was also reported by Sukumar (1990a). But, Sivaganesan and Johnsingh (1995)
concluded that, selection of food items by elephant has been influenced by factors other than
palatability and crude protein for some species of grasses. Again, feeding on grasses by
elephants in dry season, supplemented by a range of other species, would reduce the toxicity
to a great extent (Olivier, 1978a).
In addition to the plants consumed by the Asian elephant inside the Manas National
Park, they consume 21 species of cultivated crops outside the national park boundary.
Elephant which ventured out of the national park boundary, mostly the male Makhna
elephant has been responsible for consuming the cultivated crops. They mostly feed on the
Oryza sp., Saccharum officinarum and Musa sps. in the fringe village areas of the Manas
National Park depending on their higher availability and food value.
8.5.2 Staple food and Food spectrum
Asian elephant in Manas National Park has been found to utilizing 40 plant species
as regular food item throughout the year, that contributed major portion of the annual
feeding frequency (71.41%). Majority of the food plant species were grasses (21 species).
Again, more than 50 % of the annual food budget (63.33%) has been contributed by twenty
top ranking food plant species. The majority (12) of the twenty top ranking food plant
species of the elephant were grasses. This has been seen that, grass species has played a
crucial role as the food plant species of Asian elephant in Manas National Park. The grass
species in Manas National Park has available throughout the year. During the pre-monsoon
season elephant feed on new sprouts in the tall grassland areas, during monsoon season it
consumes the short grasses sparsely distributed in the understorey of the woodland habitat,
during retreating monsoon season it consumes the apical part of the pre-flowering stage
grasses in the tall grassland and during winter it consumes grasses in the wet grassland
areas. This shows that, there has been availability of grass species for Asian elephant as food
plant in Manas National Park throughout the year. Hence, the contribution of the grass
species as staple food and in the food spectrum of Asian elephant has been relatively high.
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8.5.3 Browzing, Grazing and Debarking
In Manas National Park, Asian elephant mostly being grazer and its relative
frequency was 49.34 %, however, the browzing (35.35 %) and debarking (15.31 %) on the
food plants were also observed. The grazing percentage has been found highest compared to
browsing and debarking during the pre-monsoon season (59.8%) and retreating monsoon
season (54.29%) owing to the higher availability of the new sprouts and pre-flowering stage
grasses respectively, in the grassland areas. But, with the onset of the monsoon season
elephants started utilizing the woodland habitat and browsing percentage has become
highest (61.36%) compared to browsing and debarking during the monsoon season.
Compared to browsing and debarking, the grazing has been found highest in the winter
season (57.14%) also, as during this season the elephant feed on the wet grassland areas in
Manas National Park. The debarking has been found highest during winter season (20.24%)
as compared to other seasons of the year as during this season the elephant in Manas
National Park feed highly on the bark of Bombax ceiba, Careya arborea, Dalbergia sissoo,
Acacia catechu etc.
Barnes (1982b) suggested that due to the higher protein content of grasses, elephants
might be expected to feed more on them in dry season. Olivier (1978a) suggested that the
body size and dental structure of elephants are specialized for grazing. Ishwaran (1984) has
found that, elephant used grasslands throughout the year, while browse constitute only a
small portion of the diet as it browse in proportion to their availability.
Sukumar (1985a) reported that the availability of diverse browse species was
responsible for greater use of browse by elephants in browse rich habitat in Sathyamangalam
Forest Division of Tamilnadu. Sukumar (1990b) concluded that, the diet of elephants
comprised a "proper" mixture of browse and grass in relation to seasons and vegetation
types Lindsay (1994) has also recognized elephants as being both browzers and grazers and
can fulfill energy requirements from either browse or grass, depending on availability and
quality. In areas of abundant green grass, elephant graze; but, browse makes up the majority
of the annual intake of most elephant populations in southern Africa, where grass
availability is highly seasonal (Williamson, 1975b).
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The phenology of the grassland is also another factor influencing the elephant to eat
more on the grass species in Manas National Park. Factors such as phenology (Sivaganesan,
1991) and seasonal shift in protein content of grass (Sukumar, 1985a) influences seasonal
food selection of elephants.
The higher percentage of browzing during monsoon season by Asian elephant can be
attributed to increased food quality provided by the browse species in Manas National Park.
Browse species in wet season contain higher concentration of proteins and fatty acids than in
grasses (Dougall et al., 1964; Field, 1971). Bax and Sheldrick (1963) observed a fall in the
protein content of grasses in dry season. Bax and Sheldrick (1963) described that bark eating
is in search for calcium. Laws et al. (1975) worked out a positive correlation between extent
of debarking by elephants and the calcium contents of that plant species.
Laws et al. (1975) suggested that supplementation of the diet with fibrous bark was
to maintain an optimum fibre: protein ratio. They have also reported a positive correlation
between the degree of debarking and calcium content of food plant species. Several authors
have reported a positive correlation between the bark feeding mineral content in bark (Bax
and Sheldrick, 1963; Croze, 1974; Williamson, 1975b; Guy, 1976; Olivier, 1978a). Easa
(1989) observed, the bark feeding behaviour in Parambikulam Wildlife Sanctuary and
observed difference in time spent for debarking by different age and sex classes of elephants
were non-significant except in adult males. Barnes (1980) showed that there was a
significant difference between bulls and cows in the time spent on feeding on individual
trees.
8.5.4 Geophagy
During the present study this has been observed that, the Asian elephant geophagy
sites have consistently different Na content from the nearby topsoil which has not been
licked by the Asian elephant. Animals may use the taste of NaCl as a clue to such zones
where they are likely to find a greater quantity of micronutrients relative to other soils
(Kreulen and Jager, 1984). The Asian elephant in Manas National Park has visited the
geophagy sites during the pre-monsoon season which is associated with the highest feeding
on the new sprouts in the grassland areas. As the salt lick areas have been situated in the
Indo-Bhutan border line the Asian elephant need to visit the sites crossing beyond the
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political boundary of India. Hence, the salt licking behavior of the Asian elephant is one of
the reasons for their movements into the habitats inside the Bhutan.
Dorji (1997) reported that, elephants traditionally always moved vertically from
India up into the Bhutanese foothills and west-east/east-west along this border, migrating
according to the season and availability of food. Sodium supplementation appears to be
relatively consistent in geophagy worldwide (Cowan and Brink, 1949; Weir, 1969; Moe,
1993) although Na supplementation may be a dietary factor behind geophagy worldwide
(Cowan and Brink, 1949; Weir, 1969; Weir, 1972; Moe, 1993). Sukumar (1989b) proposed
that, an Asian elephant need 75-100 gm of sodium daily in order to avoid a deficit. But,
Chandrajith et al., (2008) found in Sri Lanka that, there is no significant difference between
the geochemical composition of geophagic and non-geophagic soils. The nutritional benefits
of geophagy has depends on the chemical characteristics of the lick and the species of
animal (Mills and Milweski, 2007). Mills and Milweski (2007) wrote possibility of lick soil
contamination with the Na from the urine of animals visiting the licks. But, in the geophagy
sites of the Manas National Park, it has been seen that, the Asian elephant always uses new
locations in salt licking hills.
Olivier (1978a) had discussed in detail the sodium requirement of elephants in rain
forests of Malaya. Robbins (1983) suggested that, requirement of sodium in mammals is not
constant but can be increased by behavioural stress, reproduction and excessive potassium or
water intake. Hence, the Na content in the soils of the geophagy sites has been the
determining factor for utilizing that site for salt licking by the Asian elephant in Manas
National Park.
8.5.5 Seed Dispersal and Feeding
The present study showed that, among all the 26 species of seed germinated from the
samples collected from Asian elephant dung were mostly tree seeds and climbers has the
least germination. The majority of seeds were found passed intact. Though the elephant
does not ingest the seeds of Bombax ceiba directly, yet they are observed in the elephant
dung and found germinated during the present. This is due to the fact that, Bombax ceiba is
dispersed by wind and falls on the grass and other herbage, which the Asian elephant may
ingest as food and later observed in the dung. Emergent trees, standing dead trees or perhaps
trees with abundant fruit crops (e.g. Ficus) may attract vertebrate seed-dispersers and have
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higher seed rain than beneath trees nearby (Smith, 1975; Coates-Estrada and Estrada, 1986;
Masaki et al., 1994). Elephants disperse seeds of fruits ingested by depositing them in
faeces. Thus, for the maintenance and preservation of tropical forest as a whole, it seems
critical to maintain animals that facilitate seed dispersal (Howe 1984, Pannell, 1989).
Elephants utilized a wide variety of Acacia species in thorn forest and their seeds
were predominantly observed in dung piles during the dry season in Mudumalai Wildlife
Sanctuary, Tamilnadu (Sivaganesan, 1991). Khan (1977) reported that, fruits of 13 genera
were used by elephants in Malaysia and 5 of them represented in the diet of elephants at
Lope Reserve, Gabou. Olivier (1978a) fund that, Asian elephants in rain forest in Malaysia
ate fruits rarely. The faecal analysis revealed that, Asian elephants consumed only a small
number of seed species, despite the availability of a diverse range of fruit during the study
period (Kitamura et al., 2002).
A clear influence of dispersal ability on the distribution and persistence of threatened
plant has significant conservation implications in the MNP. Anthropogenic disturbances
such has poaching of elephant, habitat destruction, live stock grazing may lower the
abundance and diversity of seed dispersal agents and may indirectly alter plant regeneration,
especially of threatened plants. Study shows that, the most of the seedling germinated are of
tree species (65%) from the seed collected from the dung samples of Asian elephant. The
higher dispersal of the tree seed has been seen as the Asian elephant feeds on the seeds tree
species while browzing. Species like the Careya arborea, Dalbergia sissoo, Acacia catechu
have been eaten wholly including seed, bark, leaves etc. and hence, their seeds have been
dispersed. It shows that, Asian elephant plays an important role in the seed dispersal of trees
in MNP. Nevertheless, Dinerstein and Wemmer (1988; Dinerstein, 1991) showed that, the
distribution of Trewia nudiflora in riparian forests in Nepal is almost entirely attributable to
dispersal by rhinoceros and suggested that, rhinoceros dung pies provide nutrients necessary
for the seedlings. Jansen and Martin (1982) suggested that, mega-faunal extinction in the
Pleistocene resulted in loss of dispersal agents for a number of tree species in the central
African dry forests, resulting in habitat impoverishment. Hence, the Asian elephant plays an
important role in the maintenance of the plant diversity and habitat in MNP.
However, further study on the dispersal of seeds by the Asian elephant is very much
important to know its role in the maintenance of habitat and plant diversity.
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PLATE 8.1 Elephant feeding evidence and feeding process in MNP.
Left out food of Asian elephant in MNP. Undigested parts of Dillenia indica fruits in
elephant dung, MNP.
Feeding sign on climbers Butea parviflora Grazing on Saccharum elephantium in
MNP.
Browzing on Ficus religiosa in MNP Debarking on Bombax ceiba in MNP