Nutritional ecology of Asian elephant (Elephas maximus) and human-wildlife interactions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Conservation Ecology at Massey University, Albany, New Zealand
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2017
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Massey University
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Abstract
Reducing human-wildlife conflict has recently been recognised as an important aspect
of wildlife management and represents one of the most complex challenges currently
facing conservationists worldwide. Conflicts between humans and wild animals arise as
a result of the loss, degradation and fragmentation of wildlife habitats through
anthropogenic activities such as logging, animal husbandry, agricultural expansion and
infrastructure development. Habitat fragmentation results in reduced areas of habitat
and increased probability of contact between people and wild animals as the animals
move in order to meet their nutritional and other ecological and behavioural
requirements. Habitat degradation has led to food-related problems in populations of
many species of wildlife, and the Asian elephant (Elephas maximus) is particularly
vulnerable because it requires such a large amount of food per day. Large herbivores,
such as elephants, are especially likely to suffer during periodic food shortages when
they cannot meet their nutritional targets. Understanding the dietary and nutritional
needs of elephants is crucial for managing habitats in ways that will ensure their
survival, in particular by minimising conflict with humans. However, obtaining
information about the dietary requirements of wild animals is difficult.
This thesis investigates the diets and nutritional priorities of captive, domestic and wild
elephants through the application of nutritional geometry. Initially, I examined the food
intake, food composition and the resultant dietary macronutrient and fibre intake in a
captive female Asian elephant. My results showed that the proportions of the elephant’s
daily macronutrient and neutral detergent fibre (NDF) intake were different than the
proportions in the daily mixture of provisioned foods and were consistent across days,
suggesting that she was selectively feeding on available foods. Results indicated that
she prioritised the ratio of protein: non-protein energy in her diet, with the ratio of nonprotein
macronutrients (fats and non-structural carbohydrates) to digestible fibre (NDF)
being varied so as to maintain a more constant proportion of dietary protein. Similar
results in which the proportion of dietary energy contributed by protein was prioritised.
This was revealed in my study on domesticated elephants, with most elephants
maintaining constant proportional protein energy in their diet, but different individuals
achieving this by consuming different ratios of non-protein energy (NPE) to neutral
detergent fibre (NDF) energy. I also carried out a food preference survey for the wild
elephants. I found that 57 species of fodder plants in 28 families were consumed by
wild Asian elephants, including 13 species of grasses, five shrubs, two climbers, one
herb and 36 trees. The feeding preference index further showed that browse species are
preferred during the dry season, while a browse and grass combination is favoured
during the rainy season. These findings were used to test the hypothesis that the
elephants are selectively feeding against a null hypothesis that feeding is proportional to
availability. The difference in the availability and the utilisation supports the alternative
hypothesis of selective feeding to obtain the required macronutrient intake. An
investigation of human-elephant conflict through a questionnaire survey showed that
the depletion of natural forage inside and outside protected areas leads to an increase in
elephants raiding crops because the grain-laden cultivated food plants are more
palatable and more nutritious than wild browse plants. This study concluded that among
the many factors, dietary requirements and selective browsing habits are believed to be
the root causes in precipitating destructive behaviour in wild elephants, leading to fatal
human-elephant conflict. This study also found that locally in central Nepal, crop
raiding was the main cause of conflict with humans. Respondents believed that humanelephant
conflict could be minimised by re-vegetating internal parklands and park
boundaries with native elephant food plants. The study also showed that regional
conflict intensity as measured per elephant damage was high in western Nepal;
however, conflict regarding human and elephant casualties was higher in central and
eastern regions.
In summary, this study substantially advances our knowledge of the nutritional ecology
of elephants and makes a significant contribution towards understanding the dietary and
nutritional aspects of three different groups of elephants (captive, non-captive domestic
and wild), as well as the nutritional drive of human-elephant conflicts. My findings have
implications for the management of habitats for the conservation of Asian elephants and
the mitigation of human-elephant conflict.
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Keywords
Asiatic elephant, Food, Feeding and feeds, Ecology, Wildlife management, Nepal, Research Subject Categories::NATURAL SCIENCES::Biology::Terrestrial, freshwater and marine ecology::Ethology and behavioural ecology