In search of an appropriate survey technique
(For estimating biological population of Sangai and other large mammals in KLNP)

Kh Hitler Singh *

Sangai : The endemic, rare and endangered Manipur Brow-antlered deer in February 2009

Keibul Lamjao National Park (KNLP) is unique and it is the only floating Wildlife Reserve in the world having outstanding universal values outlined by UNESCO's World Heritage Centre, Paris . So its survey technique for estimating population of Sangai (Rucervus eldii eldii); the State Animal of Manipur and other large mammals found in the Park is also should be unique. The present article is the outcome of the discussion with my controlling officer Shri L. Joykumar Singh IFS, DCF/Park & Sanctuary Division, Imphal for an appropriate Survey Tecnique for estimating biological population of Sangai and other wildlife in Keibul Lamjao National Park.

The aerial Survey by using Helicopter in the early period had been discontinued because of cost involved and possible damage to Sangai population by the loud sound of the helicopter during the Census operation. Census in Wildlife management is very important as it decide the success or failure of conservation practices in the Protected Areas. But the word census in wildlife is misnomer and it should be substituted by phrase "Estimation of wild animals Population".

The ground Census "Estimation of wild animals Population" method used after aerial Survey; comprised of Construction of viewing Towers in the stratified blocks spread over the thick phumdi Zone and counting from the Machans within the laid out blocks.

This method is criticized by the scientific community on lacking of rigorous techniques and based mostly on the sighting recorded. This method had not taken care of those animals which are left not detected to the observers because of the vegetation or otherwise.

The most common, widely employed and scientific Distance Sampling method of Line Transect cannot be employed in this Park because of marshy nature of the Park. Thus a modified Point Transect (Variable Circular Plot) method with the help of fixed Machans (Elevated Viewing Points) of about 7m in height in the predetermined locations has to be employed. In all 27 Machans (including four permanent machans) are constructed covering all the thick phumdi zones which are plotted on the GIS Map. Two or three observers equipped with binoculars; who had been imparted short training shall be deployed.

Making of Machans and counting of wild animals from the top of the Machans were carried out from the early period but the collection of data from the exercise was taken as total count. But the best method for KLNP shall be the Point Transect Method.

Point Transect Method:- In this method the observer(s) is/are on a fixed point and see for animals in all directions with binoculars and recorded the number of sighting, species, male or female, fawn or young one etc. Here it is very important to distinguish male or female and Sangai and Kharsa. It is also very important to record the distance of each animal object or clusters of animals from the observing point. This is the most problematic part in Distance Sampling.

But according to Phillip Cassey (Estimating animals abundance by distance sampling technique) in point Transect Method the distance of the animals from the observer(s) need not be measured precisely but can be group in classes of distances, say 0-10m; 10-20m; 20-30m etc and the result so generated does not decrease the efficiency of the density estimate procedure.

To adopt Point Transect Method in KLNP; about 5m high bamboo poles with flag shall be erected at 100m, 200m, 300m etc from every Machans constructed so as to ascertain and categorize the distance classes of the animals sighted by comparison to the bamboo poles with flag. In addition to these simplified distance estimators; few Range Finders shall be used in some important Machans.

The Density of Animal species survey in each Point Transect = (Number of animals sighted/ ? r2)

{Where r= (r?+r?+r?+.......+rn)/n}

The density of wild animals of each spp in each Machan site shall be taken into account and calculated the average density.

The Total Estimated Animals Sighted in KLNP = The Average Density per Sq Km X The Area of Thick Phumdi Zone (=25 Sq Km).

The vegetations found in the Park are of tall grassland type mainly composed of Saccharum munja and Phragmites karka. During rainy period their height goes up-to 4 metre in good site. But in this manual calculation of density of wild animals; a very important factor called non-detection factor of animals due to vegetation, disturbance due to the presence of enumerator(s) or otherwise are not accounted.

Thus to correct this factor we need the Program DISTANCE (Laake et al 1994). This program is free and downloadable from the website http://www-ruwpa.st-and.ac.uk/distance. for studies of biological population of different species in different type of habitats.

The behavior of Sangai are also should be taken due care as it is extremely crepuscular. They are active and visible only during early morning and the late evening. So Census party should be in the field by 5.30 AM and they can stay counting up to 9.30 to 10.00 AM as they are slow to come out and to go inside. If we are taking data after 10.00 AM to 4.30 PM; we may be disappointed with the result as all the animals are taking shelter and hiding inside the tall grasses of the park in this period.

One more important factor is the season for carrying out "Estimation of wild animals Population". During March- April the grasses are low and dry. So the most appropriate time for conducting the estimation is during this period.

By importing the data of our manual Point Transect method into the DISTANCE program; the scientifically accepted figure of biological population of Sangai (Rucervus eldii eldii), Hog deer (Axis Porcinus), Wild boar (Sus scrofa) etc are derived.

The method can be employed in the Park repeatedly for monitoring of the wild population of animals in the required interval of time in future.