Estimating the density of a globally important tiger (Panthera tigris) population: using simulations to evaluate survey design in Eastern Thailand
Spatially explicit capture-recapture analysis is widely utilized for estimating densities of tigers (Panthera tigris). However, developing a robust study design capable of meeting assumptions and achieving study objectives may be difficult, particularly for low-density populations. Study design deci...
| Main Authors: | , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
Elsevier
2020
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| _version_ | 1826277623102177280 |
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| author | Ash, E Hallam, C Chanteap, P Kaszta, Z Macdonald, DW Rojanachinda, W Redford, T Harihar, A |
| author_facet | Ash, E Hallam, C Chanteap, P Kaszta, Z Macdonald, DW Rojanachinda, W Redford, T Harihar, A |
| author_sort | Ash, E |
| collection | OXFORD |
| description | Spatially explicit capture-recapture analysis is widely utilized for estimating densities of tigers (Panthera tigris). However, developing a robust study design capable of meeting assumptions and achieving study objectives may be difficult, particularly for low-density populations. Study design decisions for such fieldwork can be aided by simulations. Our goal was to (1) use simulations to investigate and evaluate study design and (2) generate a reliable estimate of density for a population of tigers in Thailand's Dong Phayayen-Khao Yai forest complex. Scenarios were parameterized with a range of potential density estimates ( and detection function parameters (g0 and σ). We designed a field-based trap configuration identified and compared it with simulated performance of a regular trapping array, over 45-day and 60-day sampling occasions. We compared simulation results (i.e. number of individuals [n], detections [ndet], relative standard error [RSE] and relative bias [RB]) and identified that the non-regular trapping array deployed for 60 sampling days would generate reliable density estimates. Our survey produced a density estimate of 0.63 ± SE0.22; (0.32–1.21) tigers per 100 km2, from a model incorporating variation in sex for g0 and σ, and a population estimate of 20 (14–33). Simulations closely reflected actual results under the null model. Our survey design performed reasonably well, generating a sufficient number of detections and individuals to estimate density of a globally important tiger population. Our results suggest simulations and use of non-regular trap arrays may be beneficial for areas with low species density in which generating sufficient detections is particularly challenging. |
| first_indexed | 2024-03-06T23:31:41Z |
| format | Journal article |
| id | oxford-uuid:6c3ff657-424e-4924-8db7-05355de4b92e |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T23:31:41Z |
| publishDate | 2020 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | oxford-uuid:6c3ff657-424e-4924-8db7-05355de4b92e2022-03-26T19:09:38ZEstimating the density of a globally important tiger (Panthera tigris) population: using simulations to evaluate survey design in Eastern ThailandJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:6c3ff657-424e-4924-8db7-05355de4b92eEnglishSymplectic ElementsElsevier2020Ash, EHallam, CChanteap, PKaszta, ZMacdonald, DWRojanachinda, WRedford, THarihar, ASpatially explicit capture-recapture analysis is widely utilized for estimating densities of tigers (Panthera tigris). However, developing a robust study design capable of meeting assumptions and achieving study objectives may be difficult, particularly for low-density populations. Study design decisions for such fieldwork can be aided by simulations. Our goal was to (1) use simulations to investigate and evaluate study design and (2) generate a reliable estimate of density for a population of tigers in Thailand's Dong Phayayen-Khao Yai forest complex. Scenarios were parameterized with a range of potential density estimates ( and detection function parameters (g0 and σ). We designed a field-based trap configuration identified and compared it with simulated performance of a regular trapping array, over 45-day and 60-day sampling occasions. We compared simulation results (i.e. number of individuals [n], detections [ndet], relative standard error [RSE] and relative bias [RB]) and identified that the non-regular trapping array deployed for 60 sampling days would generate reliable density estimates. Our survey produced a density estimate of 0.63 ± SE0.22; (0.32–1.21) tigers per 100 km2, from a model incorporating variation in sex for g0 and σ, and a population estimate of 20 (14–33). Simulations closely reflected actual results under the null model. Our survey design performed reasonably well, generating a sufficient number of detections and individuals to estimate density of a globally important tiger population. Our results suggest simulations and use of non-regular trap arrays may be beneficial for areas with low species density in which generating sufficient detections is particularly challenging. |
| spellingShingle | Ash, E Hallam, C Chanteap, P Kaszta, Z Macdonald, DW Rojanachinda, W Redford, T Harihar, A Estimating the density of a globally important tiger (Panthera tigris) population: using simulations to evaluate survey design in Eastern Thailand |
| title | Estimating the density of a globally important tiger (Panthera tigris) population: using simulations to evaluate survey design in Eastern Thailand |
| title_full | Estimating the density of a globally important tiger (Panthera tigris) population: using simulations to evaluate survey design in Eastern Thailand |
| title_fullStr | Estimating the density of a globally important tiger (Panthera tigris) population: using simulations to evaluate survey design in Eastern Thailand |
| title_full_unstemmed | Estimating the density of a globally important tiger (Panthera tigris) population: using simulations to evaluate survey design in Eastern Thailand |
| title_short | Estimating the density of a globally important tiger (Panthera tigris) population: using simulations to evaluate survey design in Eastern Thailand |
| title_sort | estimating the density of a globally important tiger panthera tigris population using simulations to evaluate survey design in eastern thailand |
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