Preserving the tigers of the Sundarbans
A roundtable on “Scientific monitoring of tigers in the Sundarbans of Bangladesh and India” was organised by Wildlife Trust of Bangladesh, in joint collaboration with Bangladesh Forest Department, on April 29-30, to formulate a joint monitoring protocol for the Sundarbans area of both Bangladesh and India.
At the roundtable papers on joint monitoring of the tigers were presented by technical tiger monitoring experts from Bangladesh, India and around the world. The experts discussed ways and means of formulating such monitoring bodies and their course of action, and how this can be implemented in the Sundarbans, maintaining its ecosystem of the area.
Some of the key findings of the workshop are mentioned below:
The objective of monitoring the tigers is to measure changes in the Sundarbans tiger population over time, so as to inform the management on conservation activities, identify threats to the tigers and assess the effectiveness of management interventions.
Tiger track survey: The khal survey will continue to gather relative abundance and occupancy data. It is agreed that track numbers are associated with tiger numbers, thus the khal survey is a valid tool to inform us on the status of tigers. An overall acceptance of the validity of the khal survey method to date was a major outcome of the roundtable.
Camera trapping: The objective of this method is to understand the relationship between tiger track sets and tiger numbers.
This will provide the observers with a number. It will be a number range not a single number. E.g. 5 to 10 tigers. This method does not need to be implemented over the whole forest area, it can be done in a number of sites. In Sundarbans we need to use attractants to bring the tigers to the camera as it has been tested on the Indian side, e.g. the use of bait, scent.
Collaring: Collars provide additional ecological data to further enrich and refine the knowledge of the observers on tiger behaviour, e.g. to verify how many times tigers cross khals, providing more information on home range sizes to help refine sample unit size for khal survey.
The number and distribution of collars will depend on the number of different ecological zones in the forest. Collars need to be clustered in each zone to get home range information and overlaps. We need to consider age and sex in each zone.
Tiger track survey, camera trapping and collaring can be conducted simultaneously in Bangladesh, as India has already been practicing this in their side of the Sundarbans.
Genetic analysis: Genetic analysis will not be used as a monitoring tool initially. It can be used as a research project by academics to further understand the genetic differences of the Sundarbans tigers.
Prey monitoring: Two methods for prey monitoring were discussed in the roundtable – pellet counting and distance sampling. Pellet counting is preferred over distance sampling where movement in the land is possible in the Sundarbans. On Bangladesh side, pellet counting is possible and a survey design has already been developed and tested.
On Indian side, this is not possible as there is no access to land, so distance sampling is used. So in the short term, each side will use a different method for prey monitoring. In the medium term both sides will work on finding a method that can be used on both sides by 2013/14.
A working group has been formed to carry on the next steps identified through this roundtable discussion. Representatives from both Bangladesh and India have been included in this working group, both from government and non government organisations. Roles and responsibilities of this working group will be to:
• Submit the summary of recommendations to the relevant authorities in Bangladesh and India
• Meet periodically to review progress and results
• Agree on scheduling of methods
• Bangladeshi working group will develop detailed methods and timetable for multi-method monitoring and agree these with relevant authorities (India has already got their methods in place).