Methods to estimate distribution and range extent of grizzly bears in the Greater Yellowstone Ecosystem

ABSTRACT The distribution of the Greater Yellowstone Ecosystem grizzly bear (Ursus arctos) population has expanded into areas unoccupied since the early 20th century. Up‐to‐date information on the area and extent of this distribution is crucial for federal, state, and tribal wildlife and land manage...

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Main Authors: Daniel D. Bjornlie, Daniel J. Thompson, Mark A. Haroldson, Charles C. Schwartz, Kerry A. Gunther, Steven L. Cain, Daniel B. Tyers, Kevin L. Frey, Bryan C. Aber
Format: Article
Language:English
Published: Wiley 2014-03-01
Series:Wildlife Society Bulletin
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Online Access:https://doi.org/10.1002/wsb.368
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author Daniel D. Bjornlie
Daniel J. Thompson
Mark A. Haroldson
Charles C. Schwartz
Kerry A. Gunther
Steven L. Cain
Daniel B. Tyers
Kevin L. Frey
Bryan C. Aber
author_facet Daniel D. Bjornlie
Daniel J. Thompson
Mark A. Haroldson
Charles C. Schwartz
Kerry A. Gunther
Steven L. Cain
Daniel B. Tyers
Kevin L. Frey
Bryan C. Aber
author_sort Daniel D. Bjornlie
collection DOAJ
description ABSTRACT The distribution of the Greater Yellowstone Ecosystem grizzly bear (Ursus arctos) population has expanded into areas unoccupied since the early 20th century. Up‐to‐date information on the area and extent of this distribution is crucial for federal, state, and tribal wildlife and land managers to make informed decisions regarding grizzly bear management. The most recent estimate of grizzly bear distribution (2004) utilized fixed‐kernel density estimators to describe distribution. This method was complex and computationally time consuming and excluded observations of unmarked bears. Our objective was to develop a technique to estimate grizzly bear distribution that would allow for the use of all verified grizzly bear location data, as well as provide the simplicity to be updated more frequently. We placed all verified grizzly bear locations from all sources from 1990 to 2004 and 1990 to 2010 onto a 3‐km × 3‐km grid and used zonal analysis and ordinary kriging to develop a predicted surface of grizzly bear distribution. We compared the area and extent of the 2004 kriging surface with the previous 2004 effort and evaluated changes in grizzly bear distribution from 2004 to 2010. The 2004 kriging surface was 2.4% smaller than the previous fixed‐kernel estimate, but more closely represented the data. Grizzly bear distribution increased 38.3% from 2004 to 2010, with most expansion in the northern and southern regions of the range. This technique can be used to provide a current estimate of grizzly bear distribution for management and conservation applications. © 2013 The Wildlife Society.
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spelling doaj-art-e37bdcc3f366472dab22afe3097cb52b2024-12-16T12:17:05ZengWileyWildlife Society Bulletin2328-55402014-03-0138118218710.1002/wsb.368Methods to estimate distribution and range extent of grizzly bears in the Greater Yellowstone EcosystemDaniel D. Bjornlie0Daniel J. Thompson1Mark A. Haroldson2Charles C. Schwartz3Kerry A. Gunther4Steven L. Cain5Daniel B. Tyers6Kevin L. Frey7Bryan C. Aber8Large Carnivore SectionWyoming Game & Fish Department260 Buena VistaLanderWY82520USALarge Carnivore SectionWyoming Game & Fish Department260 Buena VistaLanderWY82520USAUnited States Geological SurveyNorthern Rocky Mountain Science CenterInteragency Grizzly Bear Study Team2327 University WaySuite 2BozemanMT59715USAUnited States Geological SurveyNorthern Rocky Mountain Science CenterInteragency Grizzly Bear Study Team2327 University WaySuite 2BozemanMT59715USABear Management OfficeYellowstone Center for ResourcesYellowstone National ParkP.O. Box 168Yellowstone National ParkWY82190USANational Park ServiceGrand Teton National ParkP.O. Box 170MooseWY83012USAUnited States Forest Service2327 University WaySuite 2BozemanMT59715USABear Management OfficeMontana Fish, Wildlife and Parks1400 S 19th AvenueBozemanMT59718USAIdaho Department of Fish & Game/United States Forest Service3726 Highway 20Island ParkID83429USAABSTRACT The distribution of the Greater Yellowstone Ecosystem grizzly bear (Ursus arctos) population has expanded into areas unoccupied since the early 20th century. Up‐to‐date information on the area and extent of this distribution is crucial for federal, state, and tribal wildlife and land managers to make informed decisions regarding grizzly bear management. The most recent estimate of grizzly bear distribution (2004) utilized fixed‐kernel density estimators to describe distribution. This method was complex and computationally time consuming and excluded observations of unmarked bears. Our objective was to develop a technique to estimate grizzly bear distribution that would allow for the use of all verified grizzly bear location data, as well as provide the simplicity to be updated more frequently. We placed all verified grizzly bear locations from all sources from 1990 to 2004 and 1990 to 2010 onto a 3‐km × 3‐km grid and used zonal analysis and ordinary kriging to develop a predicted surface of grizzly bear distribution. We compared the area and extent of the 2004 kriging surface with the previous 2004 effort and evaluated changes in grizzly bear distribution from 2004 to 2010. The 2004 kriging surface was 2.4% smaller than the previous fixed‐kernel estimate, but more closely represented the data. Grizzly bear distribution increased 38.3% from 2004 to 2010, with most expansion in the northern and southern regions of the range. This technique can be used to provide a current estimate of grizzly bear distribution for management and conservation applications. © 2013 The Wildlife Society.https://doi.org/10.1002/wsb.368ArcGISdistributionGreater Yellowstone Ecosystemgrizzly bearkrigingrange extent
spellingShingle Daniel D. Bjornlie
Daniel J. Thompson
Mark A. Haroldson
Charles C. Schwartz
Kerry A. Gunther
Steven L. Cain
Daniel B. Tyers
Kevin L. Frey
Bryan C. Aber
Methods to estimate distribution and range extent of grizzly bears in the Greater Yellowstone Ecosystem
Wildlife Society Bulletin
ArcGIS
distribution
Greater Yellowstone Ecosystem
grizzly bear
kriging
range extent
title Methods to estimate distribution and range extent of grizzly bears in the Greater Yellowstone Ecosystem
title_full Methods to estimate distribution and range extent of grizzly bears in the Greater Yellowstone Ecosystem
title_fullStr Methods to estimate distribution and range extent of grizzly bears in the Greater Yellowstone Ecosystem
title_full_unstemmed Methods to estimate distribution and range extent of grizzly bears in the Greater Yellowstone Ecosystem
title_short Methods to estimate distribution and range extent of grizzly bears in the Greater Yellowstone Ecosystem
title_sort methods to estimate distribution and range extent of grizzly bears in the greater yellowstone ecosystem
topic ArcGIS
distribution
Greater Yellowstone Ecosystem
grizzly bear
kriging
range extent
url https://doi.org/10.1002/wsb.368
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