Report of the Tiger Task Force - PRS

TIGER TASK FORCE REPORT JOINING THE DOTS ■2. Relating to scientific and technical issues:Critique: Related to design of surveys — relationshipbetween sign index and population density may not belinear or there may be no relationship between signindex and absolute density.Response: Sign index is primarily used for determiningspatial occupancy by tigers and other carnivores.Currently, research is ongoing to establish the form ofthis relationship between sign index and populationabundance of tigers in the Satpura-Maikal landscape.Similar relationships will be estimated for alllandscape complexes.Critique: Precision in detecting population change.Response: The method proposed is conservative, thatis, reporting lower population estimates than reality.The method suffers from non-detection of tiger signswhen there is tiger presence and not vice versa.Therefore, it is unlikely to over-estimate populationsize. Thus errors, if any, will not be detrimental to theconservation decision process. There may be noise inthe sign index due to territoriality and breedingseasonality of tigers; however, such variability will beaccounted for by analysing data at a range or protectedarea level. The precision for detecting change at thesampling unit (beat) may be poor, but at a higher scale(range, division, protected area) the precision todetect change in an abundance class is likely to begood.Critique: The Satpura-Maikal pilot has notimplemented the occupancy estimation approachResponse: The information made available in thetechnical note was largely indicative of the fielddata collected in the pilot project. The intendedanalysis was also outlined. The data would beanalysed in a probabilistic framework. The signdetectionanalysis will be done following detectionprobability analysis as proposed by J A Royale, D IMacKenzie, J D Nichols and and U K Karanth. Theanalytic methods are peer reviewed and categorised:sign-detection within probabilistic framework:animal density estimation following distance samplingtheory, and tiger population estimation followingmark-capture framework.Critique: Ungulate estimation — related to convertingencounter rates to abundance.Response: Habitat specific effective strip widthsestimated by actual sampling by research team in eachlandscape complex.Critique: Tiger numbers are considered to beunimportant in the proposed methodology.Response: The proposed monitoring protocoladdresses the reality that it would not be possible toestimate tiger numbers throughout the landscape in theentire country. The hierarchical approach of theprotocol proposes to intensively monitor (numbers) inall source populations (tiger reserves and protectedareas, Phase IV). The research-level monitoring (PhaseIII) for establishing relationship between sign index andpopulation size would ensure population estimation inrepresentative samples of varying tiger density in eachlandscape complex.3 Practical problems in operation:Critique: Non-existence of beat boundaries in severaltiger-occupied landscapes.Response: The beat system exists in majority of tigeroccupied landscapes. Where the beat boundary is notdelineated, an appropriate sampling unit of 15-20 sqkm would be marked on a 1:50,000 scale map based onnatural recognisable boundaries and used as thesampling unit.Critique: Questionable reliability of data obtained byuntrained and unmotivated data collectorsResponse: Experience from Satpura-Maikal, Kuno,Sariska, Ranthambhore and Dachigam stronglysuggests that with appropriate training, the forest staffcan collect the required data with high levels ofmotivation. This system will serve to revitalise,provide a sense of belonging and ownership to theagency (forest department) responsible for theconservation of our biodiversity resources.can the Wildlife Institute of India be made the soleagency responsible for the entire spectrum ofscientific work, for that would mean failing to takeadvantage of the enormous potential in a multitudeof other Indian agencies. Indeed, in case of tigerpopulation assessment itself a great deal of work hasbeen done by groups outside not only governmentagencies, but also other research institutes anduniversities. So every effort should now be made toencourage all interested parties to participate infurthering our understanding of the tiger and itshabitat.The way ahead 77