Protocol for Monitoring Brown Bears ─ Version 1.0: Southwest Alaska Inventory and Monitoring Network

Thompson, William; Peirce, Kellie; Mangipane, Buck

This protocol narrative and associated standard operating procedures (SOPs) provide detailed information on monitoring brown bears (Ursus arctos) in four national park units in the Southwest Alaska Network (SWAN): Alagnak Wild River, Aniakchak National Monument and Preserve, Katmai National Park and Preserve (KATM) and Lake Clark National Park and Preserve (LACL). The protocol narrative provides a general overview of the history, justification, sampling methods and procedures for performing monitoring. SOPs offer step-by-step instructions for performing the various monitoring tasks and are more detailed in nature than the protocol narrative. The National Park Service initiated the “vital signs monitoring” program to address the need to observe and understand the condition of park natural resources. Vital signs can be physical, chemical, and biological elements and processes that represent the condition of a park. Brown bears were ranked as “essential” during the SWAN vital signs selection process due to their importance to ecosystem functions, usefulness as an indicator, strong linkages to other attributes in network ecosystem models and high relevance to park resource management and protection. Their ecological and management significance necessitated development of a long-term brown bear monitoring strategy for SWAN parks. The vast size, remoteness, and mountainous terrain of SWAN parks preclude ground survey methods to monitor brown bears because of extreme costs and accessibility issues. Therefore, a double-count, aerial line transect survey method modified to be conducted along elevational contours (Becker and Quang 2009) will be employed to estimate distribution, abundance, and density of brown bears in four SWAN park units. This survey technique has undergone 13 years of refinement by its developers since the first model was discussed in Quang and Becker (1996), and has been used to estimate brown bear populations in different areas in southcentral and southwestern Alaska (Becker 2003), including recent surveys by Alaska Department of Fish &Game (ADF&G) and park staffs in the ADF&G Game Management Units containing KATM and LACL during 2003-2005. A stratified random sampling design will be used to select transects primarily along elevational contours. Stratification criteria include physical features related to perceived densities of bears. Simulations based on coefficients of variation of 10%-13.5% and sampling every five years indicated a 75%-80% chance of detecting about a 1% annual decline with 90% confidence when the true annual decline was 3% during a 21-22 year period, which is the target level of detectable change. Depending on bear densities, park resources (staffing and availability of pilots), size of survey area of interest, and weather conditions, an entire survey will usually take one to three spring sessions (years) to complete. Timing of sampling will occur in May after bears have emerged from dens, but prior to leaf-out because the probability of detecting bears is highest at this time. Program GammaMRDS (Appendix B) will be used to estimate abundance and density of brown bears for the areas of interest within SWAN parks. This program will be converted to a Bayesian hierarchical modeling framework to estimate trends in abundance and density. Estimates of trend in brown bear distribution also will derive from the Bayesian hierarchical modeling framework.

Protocol for Monitoring Brown Bears ─ Version 1.0: Southwest Alaska Inventory and Monitoring Network

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