Integrating sign surveys and telemetry data for estimating brown bear ( Ursus arctos) density in the Romanian Carpathians
Abstract Accurate population size estimates are important information for sustainable wildlife management. The Romanian Carpathians harbor the largest brown bear ( Ursus arctos ) population in Europe, yet current management relies on estimates of density that lack statistical oversight and ignore un...
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crwiley:10.1002/ece3.3177 2024-06-23T07:57:21+00:00 Integrating sign surveys and telemetry data for estimating brown bear ( Ursus arctos) density in the Romanian Carpathians Popescu, Viorel D. Iosif, Ruben Pop, Mihai I. Chiriac, Silviu Bouroș, George Furnas, Brett J. Autoritatea Natională pentru Cercetare Stiintifică Consiliul National al Cercetarii Stiintifice European Commission 2017 http://dx.doi.org/10.1002/ece3.3177 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fece3.3177 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.3177 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.3177 en eng Wiley http://creativecommons.org/licenses/by/4.0/ Ecology and Evolution volume 7, issue 18, page 7134-7144 ISSN 2045-7758 2045-7758 journal-article 2017 crwiley https://doi.org/10.1002/ece3.3177 2024-05-31T08:15:10Z Abstract Accurate population size estimates are important information for sustainable wildlife management. The Romanian Carpathians harbor the largest brown bear ( Ursus arctos ) population in Europe, yet current management relies on estimates of density that lack statistical oversight and ignore uncertainty deriving from track surveys. In this study, we investigate an alternative approach to estimate brown bear density using sign surveys along transects within a novel integration of occupancy models and home range methods. We performed repeated surveys along 2‐km segments of forest roads during three distinct seasons: spring 2011, fall‐winter 2011, and spring 2012, within three game management units and a Natura 2000 site. We estimated bears abundances along transects using the number of unique tracks observed per survey occasion via N‐mixture hierarchical models, which account for imperfect detection. To obtain brown bear densities, we combined these abundances with the effective sampling area of the transects, that is, estimated as a function of the median (± bootstrapped SE ) of the core home range (5.58 ± 1.08 km 2 ) based on telemetry data from 17 bears tracked for 1‐month periods overlapping our surveys windows. Our analyses yielded average brown bear densities (and 95% confidence intervals) for the three seasons of: 11.5 (7.8–15.3), 11.3 (7.4–15.2), and 12.4 (8.6–16.3) individuals/100 km 2 . Across game management units, mean densities ranged between 7.5 and 14.8 individuals/100 km 2 . Our method incorporates multiple sources of uncertainty (e.g., effective sampling area, imperfect detection) to estimate brown bear density, but the inference fundamentally relies on unmarked individuals only. While useful as a temporary approach to monitor brown bears, we urge implementing DNA capture–recapture methods regionally to inform brown bear management and recommend increasing resources for GPS collars to improve estimates of effective sampling area. Article in Journal/Newspaper Ursus arctos Wiley Online Library Ecology and Evolution 7 18 7134 7144 |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract Accurate population size estimates are important information for sustainable wildlife management. The Romanian Carpathians harbor the largest brown bear ( Ursus arctos ) population in Europe, yet current management relies on estimates of density that lack statistical oversight and ignore uncertainty deriving from track surveys. In this study, we investigate an alternative approach to estimate brown bear density using sign surveys along transects within a novel integration of occupancy models and home range methods. We performed repeated surveys along 2‐km segments of forest roads during three distinct seasons: spring 2011, fall‐winter 2011, and spring 2012, within three game management units and a Natura 2000 site. We estimated bears abundances along transects using the number of unique tracks observed per survey occasion via N‐mixture hierarchical models, which account for imperfect detection. To obtain brown bear densities, we combined these abundances with the effective sampling area of the transects, that is, estimated as a function of the median (± bootstrapped SE ) of the core home range (5.58 ± 1.08 km 2 ) based on telemetry data from 17 bears tracked for 1‐month periods overlapping our surveys windows. Our analyses yielded average brown bear densities (and 95% confidence intervals) for the three seasons of: 11.5 (7.8–15.3), 11.3 (7.4–15.2), and 12.4 (8.6–16.3) individuals/100 km 2 . Across game management units, mean densities ranged between 7.5 and 14.8 individuals/100 km 2 . Our method incorporates multiple sources of uncertainty (e.g., effective sampling area, imperfect detection) to estimate brown bear density, but the inference fundamentally relies on unmarked individuals only. While useful as a temporary approach to monitor brown bears, we urge implementing DNA capture–recapture methods regionally to inform brown bear management and recommend increasing resources for GPS collars to improve estimates of effective sampling area. |
author2 |
Autoritatea Natională pentru Cercetare Stiintifică Consiliul National al Cercetarii Stiintifice European Commission |
format |
Article in Journal/Newspaper |
author |
Popescu, Viorel D. Iosif, Ruben Pop, Mihai I. Chiriac, Silviu Bouroș, George Furnas, Brett J. |
spellingShingle |
Popescu, Viorel D. Iosif, Ruben Pop, Mihai I. Chiriac, Silviu Bouroș, George Furnas, Brett J. Integrating sign surveys and telemetry data for estimating brown bear ( Ursus arctos) density in the Romanian Carpathians |
author_facet |
Popescu, Viorel D. Iosif, Ruben Pop, Mihai I. Chiriac, Silviu Bouroș, George Furnas, Brett J. |
author_sort |
Popescu, Viorel D. |
title |
Integrating sign surveys and telemetry data for estimating brown bear ( Ursus arctos) density in the Romanian Carpathians |
title_short |
Integrating sign surveys and telemetry data for estimating brown bear ( Ursus arctos) density in the Romanian Carpathians |
title_full |
Integrating sign surveys and telemetry data for estimating brown bear ( Ursus arctos) density in the Romanian Carpathians |
title_fullStr |
Integrating sign surveys and telemetry data for estimating brown bear ( Ursus arctos) density in the Romanian Carpathians |
title_full_unstemmed |
Integrating sign surveys and telemetry data for estimating brown bear ( Ursus arctos) density in the Romanian Carpathians |
title_sort |
integrating sign surveys and telemetry data for estimating brown bear ( ursus arctos) density in the romanian carpathians |
publisher |
Wiley |
publishDate |
2017 |
url |
http://dx.doi.org/10.1002/ece3.3177 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fece3.3177 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.3177 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.3177 |
genre |
Ursus arctos |
genre_facet |
Ursus arctos |
op_source |
Ecology and Evolution volume 7, issue 18, page 7134-7144 ISSN 2045-7758 2045-7758 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1002/ece3.3177 |
container_title |
Ecology and Evolution |
container_volume |
7 |
container_issue |
18 |
container_start_page |
7134 |
op_container_end_page |
7144 |
_version_ |
1802650955957665792 |