A comparison of population estimation techniques for individually unidentifiable free-roaming dogs

N V Meunier; A D Gibson; J Corfmat; S Mazeri; I G Handel; L Gamble; B Mde C Bronsvoort; R J Mellanby

doi:10.1186/s12917-019-1938-1

A comparison of population estimation techniques for individually unidentifiable free-roaming dogs

N V Meunier, A D Gibson, J Corfmat, S Mazeri, I G Handel, L Gamble, B Mde C Bronsvoort, R J Mellanby

Research output: Contribution to journal › Article › peer-review

Abstract / Description of output

BACKGROUND: Measuring the size of free roaming dog populations quickly and accurately is critical in the implementation of numerous preventive health and population control interventions. However, few studies have investigated the relative performance of population size assessment tools when applied to dogs. The aim of this study was to compare the commonly used mark-resight methodology with distance sampling methods, which are less resource intensive, to estimate free-roaming dog abundance in Goa, India. Twenty-six working zones were surveyed along all roads twice by the same surveyor at the same time of day, following a vaccination campaign which included marking of vaccinated dogs with a coloured paint. The Chapman estimate was then used to evaluate the mark-resight abundance. Additionally, the number of dogs and perpendicular distance from the road for all dogs sighted was recorded. This was used to estimate dog density and abundance using distance sampling methods. The detection function was fitted based on goodness-of-fit and AIC.

RESULTS: The Chapman abundance estimate for the entire study area was 5202 dogs (95%CI 4733.8-5671.0), and the distance sampling method abundance estimate was 5067 dogs (95%CI 4454.3-5764.2). For individual working zones, after taking other factors into account in a mixed effects model, the average distance sampling estimate was 35% higher (95%CI 20-53%) than the Chapman estimate. There was also evidence of a difference in estimates between surveyors of 21% (95%CI 7-37%) and between days (22% lower on day 2, 95%CI 8-38%) for individual working zones.

CONCLUSION: Our study demonstrated that the distance sampling estimates were comparable overall to the Chapman method of abundance estimation of free roaming dogs across the entire study region but there was noticeable variation between the two methods when individual zones were compared. Consequently, distance sampling methods may be suitable to enumerate dogs over large areas in a more time efficient manner than the widely used mark-resight approach.

Original language	English
Pages (from-to)	190
Journal	BMC Veterinary Research
Volume	15
Issue number	1
DOIs	https://doi.org/10.1186/s12917-019-1938-1
Publication status	Published - 7 Jun 2019

Keywords / Materials (for Non-textual outputs)

Population estimation
Dog abundance
Free-roaming dogs
Mark resight

Access to Document

10.1186/s12917-019-1938-1

A comparison of population estimation ...
This article is distributed under the terms of the Creative Commons Attribution 4.0 International Licens(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Final published version, 1.23 MBLicence: Creative Commons: Attribution (CC-BY)

Investigation of the impact of neutering on free roaming dog population dynamics
Mellanby, R.
UK-based charities
1/10/19 → 30/09/22
Project: Research

Cite this

@article{14aa741329e34d808b58765d34fa0399,

title = "A comparison of population estimation techniques for individually unidentifiable free-roaming dogs",

abstract = "BACKGROUND: Measuring the size of free roaming dog populations quickly and accurately is critical in the implementation of numerous preventive health and population control interventions. However, few studies have investigated the relative performance of population size assessment tools when applied to dogs. The aim of this study was to compare the commonly used mark-resight methodology with distance sampling methods, which are less resource intensive, to estimate free-roaming dog abundance in Goa, India. Twenty-six working zones were surveyed along all roads twice by the same surveyor at the same time of day, following a vaccination campaign which included marking of vaccinated dogs with a coloured paint. The Chapman estimate was then used to evaluate the mark-resight abundance. Additionally, the number of dogs and perpendicular distance from the road for all dogs sighted was recorded. This was used to estimate dog density and abundance using distance sampling methods. The detection function was fitted based on goodness-of-fit and AIC.RESULTS: The Chapman abundance estimate for the entire study area was 5202 dogs (95%CI 4733.8-5671.0), and the distance sampling method abundance estimate was 5067 dogs (95%CI 4454.3-5764.2). For individual working zones, after taking other factors into account in a mixed effects model, the average distance sampling estimate was 35% higher (95%CI 20-53%) than the Chapman estimate. There was also evidence of a difference in estimates between surveyors of 21% (95%CI 7-37%) and between days (22% lower on day 2, 95%CI 8-38%) for individual working zones.CONCLUSION: Our study demonstrated that the distance sampling estimates were comparable overall to the Chapman method of abundance estimation of free roaming dogs across the entire study region but there was noticeable variation between the two methods when individual zones were compared. Consequently, distance sampling methods may be suitable to enumerate dogs over large areas in a more time efficient manner than the widely used mark-resight approach.",

keywords = "Population estimation, Dog abundance, Free-roaming dogs, Mark resight",

author = "Meunier, {N V} and Gibson, {A D} and J Corfmat and S Mazeri and Handel, {I G} and L Gamble and Bronsvoort, {B Mde C} and Mellanby, {R J}",

year = "2019",

month = jun,

day = "7",

doi = "10.1186/s12917-019-1938-1",

language = "English",

volume = "15",

pages = "190",

journal = "BMC Veterinary Research",

issn = "1746-6148",

publisher = "BioMed Central",

number = "1",

}

TY - JOUR

T1 - A comparison of population estimation techniques for individually unidentifiable free-roaming dogs

AU - Meunier, N V

AU - Gibson, A D

AU - Corfmat, J

AU - Mazeri, S

AU - Handel, I G

AU - Gamble, L

AU - Bronsvoort, B Mde C

AU - Mellanby, R J

PY - 2019/6/7

Y1 - 2019/6/7

N2 - BACKGROUND: Measuring the size of free roaming dog populations quickly and accurately is critical in the implementation of numerous preventive health and population control interventions. However, few studies have investigated the relative performance of population size assessment tools when applied to dogs. The aim of this study was to compare the commonly used mark-resight methodology with distance sampling methods, which are less resource intensive, to estimate free-roaming dog abundance in Goa, India. Twenty-six working zones were surveyed along all roads twice by the same surveyor at the same time of day, following a vaccination campaign which included marking of vaccinated dogs with a coloured paint. The Chapman estimate was then used to evaluate the mark-resight abundance. Additionally, the number of dogs and perpendicular distance from the road for all dogs sighted was recorded. This was used to estimate dog density and abundance using distance sampling methods. The detection function was fitted based on goodness-of-fit and AIC.RESULTS: The Chapman abundance estimate for the entire study area was 5202 dogs (95%CI 4733.8-5671.0), and the distance sampling method abundance estimate was 5067 dogs (95%CI 4454.3-5764.2). For individual working zones, after taking other factors into account in a mixed effects model, the average distance sampling estimate was 35% higher (95%CI 20-53%) than the Chapman estimate. There was also evidence of a difference in estimates between surveyors of 21% (95%CI 7-37%) and between days (22% lower on day 2, 95%CI 8-38%) for individual working zones.CONCLUSION: Our study demonstrated that the distance sampling estimates were comparable overall to the Chapman method of abundance estimation of free roaming dogs across the entire study region but there was noticeable variation between the two methods when individual zones were compared. Consequently, distance sampling methods may be suitable to enumerate dogs over large areas in a more time efficient manner than the widely used mark-resight approach.

AB - BACKGROUND: Measuring the size of free roaming dog populations quickly and accurately is critical in the implementation of numerous preventive health and population control interventions. However, few studies have investigated the relative performance of population size assessment tools when applied to dogs. The aim of this study was to compare the commonly used mark-resight methodology with distance sampling methods, which are less resource intensive, to estimate free-roaming dog abundance in Goa, India. Twenty-six working zones were surveyed along all roads twice by the same surveyor at the same time of day, following a vaccination campaign which included marking of vaccinated dogs with a coloured paint. The Chapman estimate was then used to evaluate the mark-resight abundance. Additionally, the number of dogs and perpendicular distance from the road for all dogs sighted was recorded. This was used to estimate dog density and abundance using distance sampling methods. The detection function was fitted based on goodness-of-fit and AIC.RESULTS: The Chapman abundance estimate for the entire study area was 5202 dogs (95%CI 4733.8-5671.0), and the distance sampling method abundance estimate was 5067 dogs (95%CI 4454.3-5764.2). For individual working zones, after taking other factors into account in a mixed effects model, the average distance sampling estimate was 35% higher (95%CI 20-53%) than the Chapman estimate. There was also evidence of a difference in estimates between surveyors of 21% (95%CI 7-37%) and between days (22% lower on day 2, 95%CI 8-38%) for individual working zones.CONCLUSION: Our study demonstrated that the distance sampling estimates were comparable overall to the Chapman method of abundance estimation of free roaming dogs across the entire study region but there was noticeable variation between the two methods when individual zones were compared. Consequently, distance sampling methods may be suitable to enumerate dogs over large areas in a more time efficient manner than the widely used mark-resight approach.

KW - Population estimation

KW - Dog abundance

KW - Free-roaming dogs

KW - Mark resight

U2 - 10.1186/s12917-019-1938-1

DO - 10.1186/s12917-019-1938-1

M3 - Article

C2 - 31174545

SN - 1746-6148

VL - 15

SP - 190

JO - BMC Veterinary Research

JF - BMC Veterinary Research

IS - 1

ER -

A comparison of population estimation techniques for individually unidentifiable free-roaming dogs

Abstract / Description of output

Keywords / Materials (for Non-textual outputs)

Access to Document

Fingerprint

Projects

Investigation of the impact of neutering on free roaming dog population dynamics

Cite this