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Demographic variables for wild Asian elephants using longitudinal observations.
Shermin de Silva1, C Elizabeth Webber2, U S Weerathunga3
1Colorado State University, Department of Fish, Wildlife and Conservation Biology, Fort Collins, Colorado, United States of America ; Elephant, Forest and Environment Conservation Trust, Colombo, Sri Lanka ; Trunks & Leaves Inc., Somerville, Massachusetts, United States of America.
Plos One
|December 31, 2013
Summary
This study monitored wild Asian elephants (Elephas maximus) in Sri Lanka, revealing seasonal reproduction and higher fecundity than other populations. Males faced greater anthropogenic threats, highlighting conservation needs for this endangered species.
Area of Science:
- Wildlife Ecology
- Population Dynamics
- Conservation Biology
Background:
- Collecting demographic data for wild Asian elephants (Elephas maximus) is challenging due to habitat limitations.
- Accurate demographic data are crucial for understanding and modeling population processes of this endangered species.
Purpose of the Study:
- To present six years of demographic data from a monitored population of Asian elephants in Uda Walawe National Park, Sri Lanka.
- To analyze reproduction, mortality, and injury patterns in relation to anthropogenic factors.
Main Methods:
- Individual monitoring of over one thousand Asian elephants over six years.
- Collection of cohort-based data on mortality and reproduction.
- Analysis of birth sex ratios, age at first reproduction, inter-birth intervals, and fecundity.
Main Results:
- Reproduction was seasonal, peaking in May, with an average age at first reproduction of 13.4 years and an inter-birth interval of approximately 6 years.
- Fecundity remained stable (0.13-0.17 female offspring/individual/year) between ages 11-60.
- Males experienced significantly higher mortality and injury from anthropogenic activities compared to females.
Conclusions:
- The Uda Walawe population exhibits higher fecundity and density than other studied Asian elephant populations.
- Range constriction may influence these demographic dynamics.
- Understanding these factors is vital for the future conservation of Asian elephants.
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