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Introduction
Large herbivores are key components of terrestrial biomes because
of their relative abundance and pronounced influence on ecosystem
functioning and habitat structure. To manage and conserve these
species effectively, greater understanding of their resource requirements
at varying spatial and temporal scales is fundamental.
The Asian elephant Elephas maximus is a species of ecological
and cultural significance that has become endangered due to the
rapid decline of populations in recent decades. Human–elephant
conflict (HEC) causes a major threat to its survival in many parts
of Asia, including Sri Lanka. The critical question for wildlife
managers and ecologists is how elephant persistence can be ensured
in agricultural landscapes in the face of expanding agriculture.
Thus, a better understanding of the mechanisms and governing factors
of crop raiding by elephants, should help wildlife managers recognize
the problem and deal with it more effectively. Unfortunately, this
information is significantly limited in Sri Lanka.
This study explores the relationship of elephant food habits and
utilization of cultivated crops, considering raiding patterns throughout
the year in a human dominated landscape of southeastern dry zone
of Sri Lanka (SEDZ).
The main focus of the study was to assess whether crops were raided
as an essential resource or as a preferred resource. It was hypothesized
that, if crops were an essential resource; all elephants in an area
will raid crops, raiding will occur throughout the year without
any seasonal differences, and will involve both males and females
equally. If crops were not an essential but a preferred resource
only some animals in the area will raid crops, raiding would be
more in the wet season, and raiding by male elephants would be more
than by female herds.
Methods
To examine these hypotheses three data collection techniques were
used; ground monitoring of crop damage, macroscopic dung analysis
and micro histological analysis of plant fragments in dung. The
field work for the study was conducted over a period of one year
in four study areas.
Results
Ground monitoring of crop raiding in the four study sites indicated
that there was significant differences between male and female elephants
in raiding crops with males raiding much more than female herds.
Raiding incidents showed a seasonal increase with higher raiding
during the rainy season.
Macroscopic analysis of dung found crop seeds only in some dung
piles. Crop seeds were found more commonly in male dung than in
dung from female groups. There was a seasonal difference of crop
seeds in dung with a higher frequency of dung piles with crop seeds
during the wet season.
Micro-histological analysis of crop fragments in the dung found
crop fragments in only some dung piles. Crop fragments were more
common in dung of males than of female groups. Frequency of occurrence
of crop fragments in dung was higher in the wet season.
Discussion
Therefore the different methods used in the study in varying spatial
and temporal scales, provided similar findings, indicating that
only some elephants raided crops, males raided more than females,
raiding was seasonal and higher in the wet season. Thus I conclude
that elephants in SEDZ Sri Lanka raid crops not as an essential
but a preferred resource.
Therefore, conservation practices should focus on effective mitigation
measures to prevent elephant damage, because resources within the
ranges of elephants in SEDZ Sri Lanka are fairly stable and sufficient
for their survival without consuming crops. Many elephants in the
SEDZ Sri Lanka, including those in the study areas, have ranges
outside protected areas. Therefore, if HEC can be mitigated successfully
elephants can remain in these areas for the future. Management of
elephants outside protected areas is important for the conservation
of elephants in Sri Lanka.
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