Optimal timing to estimate moose Alces alces demographic parameters using remote cameras

Area of Science:

• Wildlife ecology and management
• Conservation biology
• Population dynamics

Background:

• Accurate demographic parameter estimation is vital for effective species management.
• Survey timing, duration, and camera placement significantly impact estimate precision and accuracy.

Purpose of the Study:

• To evaluate the influence of survey duration, timing, camera density, and placement on moose (Alces alces) detection rates, demographic ratios, and relative abundance estimates in Isle Royale National Park.
• To identify optimal survey strategies for precise and accurate moose population monitoring.

Main Methods:

• Utilized motion-activated camera images to collect data on moose.
• Analyzed detection rates, sex and age ratios (calf:cow, bull:cow), and relative abundance estimates.
• Investigated the effects of varying survey durations, timings, camera densities (cameras/km²), and on- vs. off-trail placement.

Main Results:

• Detection rates varied with moose life history patterns, indicating optimal survey periods.
• 25-day surveys during mid-June–mid-July and early December–early January yielded consistent and precise calf:cow and bull:cow ratios.
• On-trail cameras increased detection rates and relative abundance estimates but reduced precision for summer ratios; higher camera densities (>3 cameras/km²) improved precision and consistency.

Conclusions:

• Optimal survey periods for moose demographic parameters are linked to life history events and high detection rates.
• Recommended survey strategy: 25-day periods in mid-June–mid-July and December–January, using >3 cameras/km² placed on and off-trail for estimating relative abundance.
• The methodology can be adapted for optimizing survey strategies for other species.