Variation in Black Bear Home Ranges in Relation to Preferred Foods in Sequoia & Kings Canyon Nat’l Parks Rachel Mazur, Karen Folger, and Pete Klimley

Location of Sequoia and Kings Canyon, National Parks within California

Research Questions: 1.How much do the sizes of black bear home ranges vary by year? 2.Is it possible to explain any variation by measuring the availability of critical fall foods? 3.Are bears exhibiting preferences among habitat types or simply using them in proportion to their availability? 4.Are there fewer human-bear incidents when bears are foraging on higher quality foods?

Scenario 1 Scenario 2 Scenario 3 = Summer Habitat = Fall Habitat KEY = Bear’s Range

GPS Radio Collars Wild adult female bears Store-on-board units – programmed to fall off Locations recorded every hour (Aug-Oct) 1 Bear in Bears each in 2005 and Bear had data for both 2004 and Bears had data for both 2005 and 2006

Core Area Mapping from GPS points Kernals used to calculated home ranges using Home Range Tools extension to ArcGIS Old days used VHF telemetry with a few points to estimate Core areas are most used areas within Home Range

Total Habitat Area – All Bears Core Habitat Area – All Bears

Variation in annual acorn crops in Sequoia National Park

2004 Bear

2005 Bear

Relationships between food source availability and core use areas

Scenario 1 Scenario 2 Scenario 3 = Summer Habitat = Fall Habitat KEY = Bear’s Range

Human-Bear Incidents

Research Questions: 1.How much do the sizes of black bear home ranges vary by year? Depends on food. 2.Is it possible to explain any variation by measuring the availability of critical fall foods? YES! 3.Are bears exhibiting preferences among habitat types or simply using them in proportion to their availability? QUALITY! 4.Are there fewer human-bear incidents when bears are foraging on higher quality foods? YES!

2007 and 2008 Data 9 Collars on in 2007 for 2 years Collars to fall off October 31, 2008

Please save the bears.