Tiger Monitoring Report Oct 2009 Coincise Report (1)

8/13/2019 Tiger Monitoring Report Oct 2009 Coincise Report (1)

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TIGER AND THEIR PREY BASE ABUNDANCE IN

TERAI ARC LANDSCAPE

NEPAL

Ministry of Forests and Soil Conservation

Department of National Parks and Wildlife Conservation

and Department of Forests

October, 2009


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Copyright 2009, Government of Nepal, Ministry of Forests and Soil Conservation,

Department of National Parks and Wildlife Conservation and Department of Forests

Authors: Karki, J. B.1

; Jnawali, S. R.3

; Shrestha, R.4

; Pandey, M. B.1

; Gurung, G.4

; Thapa(Karki), M.

2

1Department of National Parks and Wildlife Conservation,

2Department of Forests

3National Trust for Nature Conservation,

4WWF Nepal Program,

Central Level Steering Committee

Coordinator: Director General, DNPWC

Member: Director General, DoF

Member: Member Secretary, NTNC

Member: Country Representative, WWF Nepal

Central Level Technical Committee

Coordinator: Director General, DNPWC

Members: MoFSC, DNPWC , DoF , NTNC. WWF Nepal

Field Level Committees

Coordination: Chief Conservation Officer of the respective PAs

Members: Field Office in-charges of NTNC of respective PAs

TAL Coordinator and Project Co managers

DFOs of corresponding District Forest Officers

Chairpersons of respective PA - BZs

Commanders of respective PA protection units


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A brief report on estimating abundance of tiger and its prey base in the Terai Arc

Landscape of Nepal

BackgroundThe tiger is an icon of Asias natural heritage and ecological integrity, and has great cultural

esteem. They have been serving as a flagship species to derive worldwide conservation attention

not only to benefit them but also to facilitate the survival of other associated species. As an

indicator of ecosystem health, securing the future of tigers in wild has far-reaching biodiversity

implications. Ironically, tigers have now become unsafe for their numbers are rapidly declining.

The current global tiger population is believed to comprise only 5 per cent of what was there just

a century ago.

In Nepal, tiger (Panthera tigeris) populations are fragmented and are distributed mainly in fourPAs - Parsa Wildlife Reserve, Chitwan National Park, Bardia National Park and Shuklaphanta

Wildlife Reserve (Figure 1.1). In an attempt to save the remaining tiger populations, the

Government of Nepal (GoN) devised landscape scale conservation strategies for Nepal under the

framework of the Terai Arc Landscape (TAL) program in 2004 (GoN 2004).

The design of TAL essentially follows the tiger dispersal model and the TAL region (Figure 1.1) is

recognized as one of the global priority landscapes for tigers (Wikramanayake et al., 1998).

Ecological studies of tigers (Sunquist 1981, Smith 1993) and regional-scale conservation maps

(Wikramanayake et al. 1999, 2004, Smith et al. 1999) however, show that TAL alluvial grasslands

are among the highly threatened tiger habitats in the world (Figure 1). Conservation initiatives

here require, more than ever before, a reliable ecological knowledge to undertake the scientific

management of tiger populations (GoN 2008).

Knowledge about population parameters plays a pivotal role in virtually all aspects of

conservation and management of the concerned species, making the application of biostatistics

to estimate, animal abundance very relevant in the field of wildlife management. In Nepal,

available tiger population estimates mostly come from Chitwan National Park. These are basedon either radio-telemetry (Sunquist 1981, Smith 1993, Smith et al. 1999) or claims of being able

to recognize a small number of individual tigers from their tracks (McDougal 1999). Although they

provide a starting point, such methods do not explicitly deal with the two key issues of animal

population estimation: incomplete spatial sampling of the area of interest and incomplete

detection of animals even within the area that is sampled. It is now clearly recognized that

population sampling approaches that explicitly deal with these two problems by employing


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appropriate statistical models are essential for robust estimation of animal abundance (Seber

1982, Williams et al. 2002, Thompson 2004).

Our attempt here has been to establish reliable landscape scale benchmark data on thepopulation status and distribution of the tiger and its prey base by employing cutting-edge

science. Such data will serve as a basis for future management, facilitate objective assessment of

the effectiveness of conservation interventions and help establish a body of empirical and

theoretical knowledge to enhance the predictive capacity to deal with new situations (Karanth &

Nichols, 2002). We also envisaged establishing permanent monitoring systems by following a

standardized protocol. As the efficient implementation of a monitoring protocol depends on the

knowledge and skill of field personnel, we created a pool of highly trained wildlife technicians

amongst stakeholder and decision-making groups through capacity building activities. The

information generated through monitoring activities needed to be stored systematically to ensure

the effective data retrieval as and when required. Thus, development of a sound data base

management system was also an outcome of this work.

The specific objectives were as follows;

1. Population estimation of tiger and their prey in Parsa WR, Chitwan NP, Bardia NP and

Shuklaphanta WR.

2. Assessment of tiger distribution both inside and outside of the PAs

3. Development of a database system for tiger conservation in the TAL of Nepal

4. Capacity building of DNPWC, DOF and NTNC personnel on technical skills and scientific

knowledge of tiger monitoring.

The funding support for this project has been provided by the Save the Tiger Fund (STF), US

Fish and Wildlife Services (USFWS), World Wildlife Fund (WWF) US, WWF-UK, WWF-

International. The field implementation of the program was jointly implemented by the Department

of National Parks and Wildlife Conservation (DNPWC), Department of Forests (DOF), the

National Trust for Nature Conservation (NTNC) and WWF- Nepal.


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Figure 1: Terai Arc Landscape (TAL) of Nepal

Implementation procedure and major findings

Project implementation began by preparing the standardized tiger monitoring protocol and

instituting an implementation mechanism under the leadership of DNPWC assisted by DoF,

NTNC and WWF Nepal. Prior to the field surveys, extensive hands-on training sessions were

organised to implement the monitoring protocol and thus to assess the abundance and

distribution of tigers and their prey base in TAL of Nepal.

The survey followed three contemporary approaches of assessing animal abundance and

distribution:

1. Camera trap surveys to estimate tiger populations in Parsa WR, Chitwan NP, Bardia NP,

and Shuklaphanta WR,2. Line transect surveys to assess the prey abundance in the Pas, and

3. Habitat occupancy modelling to examine the tiger distribution patterns both inside and

outside of the PAs.


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Figure 2. Training on monitoring techniques

Camera trap surveys were undertaken from December 2008 to March 2009 by systematically

placing 150 pairs of passive cameras in designated blocks in all four PAs. With a total sampling

effort of 10,305 trap nights in four PAs, we positively identified a total of 86 individual tigers

(Parsa WR - 4, Chitwan NP - 59, Bardia NP - 16 and Suklaphanta WR - 7) on the basis of their

unique stripe pattern on the body flanks, legs, face and tail. Using closed capture-recapture

sampling framework as provided by Program Capture, we estimated a total of 121 adult tigers

(i.e., excluding cubs and juveniles) in four PAs. Tiger densities were obtained by deriving

effectively sampled area through the 1/2MMDM (1/2 mean maximum distance moved) approach.

Density results were later cross verified with the Bayesian approach. As both the methods gave

similar results (paired t-test; t = 1.538, df = 3, P=0.22), we report the density estimates obtained

through the former approach. Table 1 shows a summary of tiger population status in four PAs

(Table 1).

Table 1. Status of the tiger population in the Parsa WR, Chitwan NP, Bardia NP and

Shuklaphanta WR

Estimated tiger numbers DensityProtected Areas

N SE 95% Confidence

Interval

Tigers/

100 km2

SE

Parsa WR 4 0.22 4 - 4 0.72 3.23

Chitwan NP 91 17.79 71 - 147 8.08 0.06

Bardia NP 18 2.5 17 - 29 1.76 0.26

Shuklaphanta WR 8 1.41 8 -14 3.23 0.60

Total 121 100 - 191


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The abundance of tiger wild prey animals were estimated by employing line transects surveys

within the Distance Sampling framework. The field work was conducted during May - June 2008.

A total of 463 transects were systematically surveyed for wild prey animals. We used software

Distance Version 6 for survey design and data analysis. We analysed all wild prey first as one

group in each PA and then, given the adequate number of observations, repeated the analyses

by species. Suboptimal preys, such as hare and langurs, etc. were excluded from the data

analysis as were domestic livestock. Table 2 summarizes the status of tiger s prey status in four

PAs.

Table 2. Status of the tigers wild prey in Parsa WR, Chitwan NP, Bardia NP & Shuklaphanta WR.

Density AbundanceProtected Area Wild prey

typeAnimals

(km2)

SE 95% CI Animals 95% CI

Parsa WR*

All 5.5 1.3 3.5 - 8.7 1334 841 - 2114

Chitwan NP All 62.6 7.7 49.3 - 79.5 38,319 30,165 - 48,678

Chital 43.9 10.6 27.5 - 70.0 26,849 16,836 - 42,818

Samber 7.5 1.6 5.0 - 11.2 4,567 3,044 - 6853

Wild boar 4.2 0.9 2.9 - 6.2 2,573 1,742 - 3,801

Barking deer 3.7 0.6 2.6 - 5.2 2,265 1,618 - 3,170

Hog deer 5.1 1.0 3.5 - 7.6 3,143 2,134 - 4,631

Bardia NP All 67.8 9.5 51.6 - 89.2 22,124 16,831 - 29,082

Chital 55.4 8.9 40.5 - 75.8 18,053 13,191 - 24,708

Wild boar 4.0 1.2 2.3 - 7.1 1,310 738 - 2,325

Barking deer 1.3 0.3 0.8 - 2.0 421 271- 654

Samber 2.4 0.6 1.6 - 3.8 794 505 - 1,248

Shuklaphanta WR All 86.2 15.0 61.5 - 120.8 16,994 12,128 - 23,811

Chital 54.1 14.3 32.5 - 90.1 10,665 6,406 - 17,755

Hog deer 16.3 3.2 11.0 - 23.8 3,187 2,169 - 4,682

Swamp deer 21.5 10.8 8.5 - 54.4 4,246 1,682 - 10,720

*Not enough observations to examine individual species


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During May June 2009 after the burning, habitat occupancy surveys were carried out across all

four PAs, their buffer zones and adjoining potential tiger habitats. Ninety-six grids (15 x 15 km2)

were surveyed for evidence of tiger as well as tiger prey and human activities (Figure 3). The later

two variables served as covariates to model the habitat occupancy by tigers. Program Presence

Version 2 was used to model the habitat occupancy by fitting the detection/non-detection data.

The model incorporating prey index was the best performing model to describe habitat occupancy

by tigers in the study area. The model-averaged estimate among top models of the probability of

occupancy for a grid cell with prey index of medium-high was 0.94 (SE = 0.07). Where prey were

ranked low, the probability of occupancy was estimated at 0.21 (SE = 0.06). The effect of the

human impacts index switching from high to low only increased the probability of occupancy by

0.06 (7% increase) in sites where the prey index was already med-high. The model - averaged

estimate of the probability of detection for surveys with an observer expertise index of good was

0.73 (SE = 0.05, Table 5.4). Using the top model with !AIC = 0, and AIC weight (w) of 0.59, the

tiger habitat occupancy pattern in the TAL ranged from 0.24 (SE = 0.05) to 0.95 (SE = 0.06).

Conclusion and recommendations

This monitoring is a milestone for the tiger conservation initiatives in Nepal as it has established

the benchmark data on population status of tigers, their prey base and distribution. This is

especially true in the context that past attempts were made in different spatial and temporal

scales and often with less statistical rigor.

Our camera trap survey revealed the presence of 121 adult tigers in Nepal. Compared to records

from 2005 (GON, 2008), tiger population in Chitwan NP increased substantially while there is

drastic decline in Bardia NP and Shuklaphanta WR. Prey depletion has been recognized as the

single most factor driving the current decline of wild tiger populations and hence a significant

constraint on their recovery (Karanth & Stith, 1999). Our results from habitat occupancy surveys

are consistent with this. Comparing the influence of two covariates, human disturbance and prey

availability, we clearly demonstrated that the habitat occupancy by tigers was more affected by

prey abundance than the human disturbance. Whether the prey index was low versus medium-

high was highly influential in predicting tiger occupancy. The 4 models containing the prey index

covariate ranked as the top 4 based on AIC comparisons. Therefore, the prey base possibly

constitutes the most important criteria for predicting tiger occupancy. Otherwise suitable areas

that have depleted prey bases should be managed with an important focus on increasing the prey

base.


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However, there were additional human impacts not fully captured in the prey index covariate (i.e.,

human impacts on tiger occupancy in ways beyond influencing the relative abundance of the tiger

prey base) as suggested by model 10 having a !AIC of 0.70 from the top model (and also note

model 7 had a !AIC of 1.06 relative to model 9). Because the human impacts covariate

incorporated livestock presence, the impact of humans on vegetation, fires and evidence of

poaching mitigating these factors should be considered to increase tiger occupancy even in areas

where the prey base is already deemed sufficient. This is particularly true in the case of

Shuklaphanta WR and Bardia NP, where the existing level of prey population appear to be

adequate to support the viable tiger populations (Karanth et al., 2004). Increased incidence of

tiger poaching in Shuklaphanta WR and Bardia NP in the recent times indicated the poaching as

the most plausible reason for the decline in tiger numbers.

Thus, it is essential that management to focus on managing wild prey base of tigers and curbingongoing poaching and trade in their parts for effective recovery of tiger populations in Nepal.

References

GoN (2008). Tiger conservation action plan for Nepal. Kathmandu: Department of National Parks

and Wildlife Conservation.

Karanth, K. U. , Nichols, J. D. (Eds.) (2002) Monitoring tigers and their prey: A manual for

researchers, managers and conservationists in tropical asia, Banglore, India, Centre for Wildlife

Studies.

Karanth, K. U., et al. (2004). Tigers and their prey: Predicting carnivore densities from prey

abundance In: Proceedings of the National Academy of Sciences of the United States of America

4854-4858.). USA.

Karanth, K. U. , Stith, M. (1999). Prey depletion as a critical determinant of tiger population viability.

In: Riding the tiger: Tiger conservation in human-dominated landscapes: 100-113. Seidensticker,

J., Christie, S. , Jackson, P. (Eds.). Cambridge, UK: Cambridge University Press.

McDougal 1999


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Seber, G. A. F. 1982. The estimation of animal abundance and related parameters. Macmillan, New

York, NY, USA.

Smith, J. L. D.1993. The role of dispersal in structuring the Chitwan tiger population. Behavior 124:

165-195.

Smith, J. L. D., S.C.Ahearn and C.McDougal.(1998). Landscape Analysis of Tiger

Distribution and Habitat Quality in Nepal.Conservation Biology 12,1998: 1-9.

Snquist,M.E.1981.The social organization of tigers (Panthera tigris) in Royal Chitwan National Park,

Nepal. Smithsonian Contribution to Zoology, 336,1-98.

Thompson 2004

Wikramanayake et al. 1999

Wikramanayake, E., McKnight, M., Dinerstein, E., Joshi, A., Gurung, B. and Smith,D. 2004. Designing

a conservation landscape for tigers in human-dominated environments..Conservation Biology.

18: 839-844.

Wikramanayake, E. D., et al. (1998). An ecology-based method for defining priorities for large

mammal conservation: The tiger as a case study. Conservation Biology, 12: 865-878.

Williams, B. K., Nichols, J. D. , Conroy, M. J. (2002). Analysis and management of animal populations.

San Diego, California, USA: Academic Press.


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Tiger Monitoring Report Oct 2009 Coincise Report (1)