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Evaluation of Line Transect Sampling Technique in Estimating Elephant Abundance in Forests Using Dung Survey


Affiliations
1 Southern Regional Station, National Dairy Research Institute, Bangalore, India
2 Kerala Forest Research Institute, Peechi, Thrissur District 680 653 Kerala, India
     

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Line transect sampling technique is widely applied for estimating the biological population in forests. Recently, this technique has been in use for the estimation of elephant abundance using dung survey. The method of transforming dung count into elephant density requires dung density, which is corrected by defecation and decay rate. In this paper, the performance of the line transect sampling technique (LTS) in dung surveys with particular reference to variation in the number of detections of dung piles caused by annual rainfall variability was evaluated. The data set for this purpose was from the estimation of elephant population in the State of Kerala during the years 2005, 2007 and 2010, covering about 9000 km2. The study showed that the presence of dung piles and its detection probability were dependent on the level of rainfall in the two months preceding the date of dung survey. However, the LTS could provide comparable dung density estimates under the highly varying number of dung piles present in the area due to differences in the annual rainfall pattern.

Keywords

Distance Sampling, Detection Probability, Elephant Density, Rainfall Variability.
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About The Authors

M. Sivaram
Southern Regional Station, National Dairy Research Institute, Bangalore
India

K. K. Ramachandran
Kerala Forest Research Institute, Peechi, Thrissur District 680 653 Kerala
India

E. A. Jayson
Kerala Forest Research Institute, Peechi, Thrissur District 680 653 Kerala
India

P. V. Nair
Kerala Forest Research Institute, Peechi, Thrissur District 680 653 Kerala
India


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  • Evaluation of Line Transect Sampling Technique in Estimating Elephant Abundance in Forests Using Dung Survey

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Authors

M. Sivaram
Southern Regional Station, National Dairy Research Institute, Bangalore, India
K. K. Ramachandran
Kerala Forest Research Institute, Peechi, Thrissur District 680 653 Kerala, India
E. A. Jayson
Kerala Forest Research Institute, Peechi, Thrissur District 680 653 Kerala, India
P. V. Nair
Kerala Forest Research Institute, Peechi, Thrissur District 680 653 Kerala, India

Abstract


Line transect sampling technique is widely applied for estimating the biological population in forests. Recently, this technique has been in use for the estimation of elephant abundance using dung survey. The method of transforming dung count into elephant density requires dung density, which is corrected by defecation and decay rate. In this paper, the performance of the line transect sampling technique (LTS) in dung surveys with particular reference to variation in the number of detections of dung piles caused by annual rainfall variability was evaluated. The data set for this purpose was from the estimation of elephant population in the State of Kerala during the years 2005, 2007 and 2010, covering about 9000 km2. The study showed that the presence of dung piles and its detection probability were dependent on the level of rainfall in the two months preceding the date of dung survey. However, the LTS could provide comparable dung density estimates under the highly varying number of dung piles present in the area due to differences in the annual rainfall pattern.

Keywords


Distance Sampling, Detection Probability, Elephant Density, Rainfall Variability.

References