ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)

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#527

04-02-2015, 01:15 AM

A Suggested Protocol for Radio-Telemetry Studies on Tiger (Panthera tigris L.)
By Dr Aniruddha Majumder & Mr S.P. Yadav 2014

-INTRODUCTION
"Tiger (Panthera tigris L.) is the largest of all the felids found in diverse habitat types and show remarkable tolerance to variation in altitude, temperature and rainfall regimes (Sunquist et al. 1999). They can potentially hunt prey varying from small mammals to large bovids (Sunquist 1981; Majumder et al. 2013). They are territorial and wide ranging and the effective size of the territory is a function of density and biomass of prey species in its habitat (Smith et al. 1987a; Smith et al. 1987b; Majumder et al. 2012). Therefore studies undertaken to address these issues on tiger are important because it can provide a better insight of tiger ecology and behavior. Radio-telemetry is such a method that has been effectively used to address these questions (Quigley et al. 1989; Smith et al. 1987a; Sunquist 2010; Barlow et al. 2010; Goodrich et al. 2010; Sharma et al. 2010; Majumder et al. 2012).    Radio-tracking is the technique of determining information about an animal through the use of radio signals from or to a device carried by the animal and the first functional telemetry system created by Cochran and Lord (1963). “Telemetry” is the transmission of information through the atmosphere usually by radio waves, so radio-tracking involves telemetry, and there is much overlap between the two concepts (Mech and Barber 2002). The basic components of a radio- tracking system are (1) a transmitting subsystem consisting of a radio transmitter, a power source and a propagating antenna, and (2) a receiving subsystem including a “pick-up” antenna, a signal receiver with reception indicator (speaker and/or display) and a power source. Most radio tracking systems involve transmitters tuned to different frequencies (analogous to different AM/FM radio stations) that allow individual identification. Three distinct types of radio-tracking are mainly in use today: (1) Very High Frequency (VHF) radio tracking, (2) satellite tracking, and (3) Global Positioning System (GPS) tracking (Mech and Barber 2002). VHF radio-tracking is the standard technique in use since 1963. An animal wearing a VHF transmitter can be tracked by a person on the ground or in the air with a special receiver and directional antenna. Briefly, the advantages of VHF tracking are relatively low cost, reasonable
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accuracy for most purposes, and long life; disadvantages are that it is labor-intensive and can be weather-dependent if aircraft-based. Nevertheless, VHF radio-tracking is by far the most useful and versatile type of radio-tracking, for not only does it yield location data, but it also allows investigators to gather a variety of other types of information (Mech 1974, 1980, 1983). Satellite tracking employs a much higher-powered transmitter attached to an animal. The signal is received by satellites and the animal‟s calculated location is sent to a researcher‟s computer. Satellite tracking requires a much higher initial cost and is much less accurate (mean accuracy = 480 meters [Fancy et al. 1989]) and, for most species, is shorter-lived than VHF systems. If only animal locations and gross movements are of interest to a study, such as a dispersal path, satellite tracking is advantageous because it requires no personnel in the field once the tracking device is placed on the animal. It is especially useful for monitoring long-range movements. However, most wildlife studies also require a variety of other information that satellite tracking does not provide, including number of companions, individual productivity, behavior, and population size and trend. For carnivores, information about predatory habits, such as rates, location, species, age, sex, and condition of their kills, cannot be obtained by satellite tracking. GPS tracking of animals is the latest major development in wildlife telemetry. It uses a GPS receiver in an animal collar to calculate and record the animal‟s location, time, and date at programmed intervals, based on signals received from a special set of satellites. GPS tracking is based on a radio receiver (rather than a transmitter) in an animal‟s collar. The receiver picks up signals from a special set of satellites and uses an attached computer to calculate and store the animal‟s locations periodically (e.g. once/15 minutes, once per hour, etc.). Depending on collar weight, some GPS collars store the data and drop off the animal when expired to allow data retrieval; others transmit the data to another set of satellites that relay it to the researchers; and still others send the data on a programmed schedule (e.g., daily) to biologists who must be in the field to receive them. GPS tracking also has high initial costs and at present is relatively short- lived and applicable to mammals the size of a wolf or larger, or to birds on which solar cells can be used. GPS tracking is highly accurate and especially suited to studies where intensive and frequent data many locations/day) are needed or useful. Depending on several variables, GPS tracking may or may not require frequent field visits (Mech and Barber 2002). Though in recent days, radio-collared with inbuilt cameras have been used in various studies, it is not suggested in case of tiger, as it is too bulky with too short a battery life to justify the whole
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effort and risk associated with this type of collar (Kaustubh Sharma pers comms). However, the pace at this technology is developing and will soon become practical. Along with knowledge on various tools used for radio-telemetry study, it is also important to have practical understanding while handling an immobilized tiger at the time of fitting radio collar. The Global Tiger Forum (GTF)-mandated to conserve tiger in the wild, had compared various literatures on radio-telemetry studies and suggested a Protocol on Radio-Telemetry studies on tiger for manager and biologists of Tiger Range Countries (TRCs). This will help to augment the domain knowledge on the tools and technologies used for radio-telemetry studies on tiger and can be also used by TRCs to study ecological and management studies of tiger movement, behavior, habitat use, survival, and productivity assessments."

Important steps to be followed once the tiger is darted
1) Carefully observe the sedated animal from a safe distance (left picture), whether it is completely sedated or not. A stick can be bitten on the ground for making soft sound. Animals panic when distressed and will flee from the source of disturbance until they are exhausted and can die of resultant heart failure, termed capture myopathy (Ebedes et al. 2002). For this reason, the stress imposed on wild animals during capture and handling should be kept to a minimum and loud noises and movement should be avoided.
2) If the animal under complete sleep, dart need to be removed. Blindfolding to protect the cornea from direct sunlight, dust and injury (above pictures).
                           Fig 11a and 11b. Ideal animal position after sedation 3) Ensuring proper animal positioning (sternal or lateral recumbancy) to maintain patent airways and ensure normal breathing and circulation (Fig 11a and 11b). 4) Assessing the status of animal, the degree of muscle relaxation and the rate and depth of respiration. 5) Assessment of anesthesia should be done using following methods: i) Monitor tissue perfusion: Anesthetic drugs frequently depress the contractile force of the heart and vasodilatation results in decreased tissue perfusion. ii) Evaluation of tissue perfusion should be done by observation, auscultation, palpation and capillary refill time. iii) Monitor gas exchange: Respiratory rates are highly variable during anesthesia. iv) Quality of respiration should be evaluated by observing animal‟s chest movement. v) Monitor level of CNS depression by assessing the muscle tone-jaw tone and eye reflexes. vi) Monitor vital signs such as respiration, heart rate and body temperature. vii) Examine animal for any wound or injuries (including status of canines and claws).

Tigers sedated