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Webinar: Comparing Methods
2020-12-16 @ 12:00 – 13:00 MST
Our final webinar of 2020 discussed automated approaches to data collection in the field with remote cameras and audio recorders. In our Comparing Methods webinar, our speakers focused on the application of these technologies and the implications for methodological approach, analysis, and overall results.
Read the speaker abstracts.
Camille Warbington from the University of Alberta started the webinar by discussing the use of camera traps in Africa in estimating density of wildlife. She compared analyses focused on spatially explicit capture-recapture (SECR) and time in front of the camera. Although researchers frequently use SECR models, not all wildlife populations fit these model assumptions. For example, the direction of movement away from the activity centre (the camera) can sway density estimates because of varying home range shapes. Camille explored alternative models. One used a network distance to calculate density and resulted in an estimate of animals/km of habitat. She also tested a rest model that does not require individual identification or movement rates (this was the Time In Front of Camera, or TIFC model). She presented results on density estimates from the different models and showed that results were comparable without some model limitations. Her results suggest that TIFC models can be an alternative to SECR when the species violates model assumptions.
Tyne Baker from A/Vian Eco discussed her field tests comparing autonomous audio recording units. The goal of these tests was to define any difference in data capture between devices of varied age and price, and to compare the magnitude of these differences to the biologically relevant signal radius. Tyne used a paired playback design to compare units in real-world recording conditions using stimuli of varied acoustic properties. Her results show recording quality is comparable but there is a small gap in stimuli captured by devices. Industry-standard, higher-cost devices may assist in capture for some types of signals (eg. high-frequency signals, broadband sound and stimuli with sound characteristics matching background noise). Older cheaper devices may be best used in tighter spatial configurations, over longer periods of time, in areas with low ambient noise, and for species with signals that travel greater distances (large signal radii). Comparing between sites that have different recorder types without a correction factor is not recommended. Overall both the signal characteristics of the target species and the capabilities of the recording device should be considered when designing an acoustic monitoring program.
Our final 2020 webinar wrapped up with Marcus Becker from ABMI. Marcus presenting some lessons learned from ABMI’s five years of mammal monitoring in Alberta by remote camera. The ABMI has been using the Rest model to estimate mammal density that Camille discussed in her talk. By mounting a pole 5m from the camera, ABMI is also examining camera reliability to be triggered at distances greater than 5m. The overall goal of the project is to report on species abundance. Their approach uses a grid system with several cameras in each grid over time; each camera is representative of a much larger spatial area. Data for each camera is summarized and a confidence estimate is calculated. When Marcus compared the camera abundance estimates to traditional aerial surveys, he found that cameras overestimated density. This is confounded by the fact that some species are attracted to the camera and the pole, thus spending more time in front of the camera. He is now working on models that parse out the playful or curious behaviour on camera, as well as looking at microhabitat selection for camera placement.
This webinar was attended by 40 people and 95% them thought the webinar was useful. Most participants would recommend ACTWS webinars to others, and half of them were repeat webinar participants! That is what we like to see!
Join us in January as we ring in a new year of lunch and learn webinars. Our first webinar will discuss Parasite and Disease Transmission. Details to come on our events page.
See the Webinar!
A video of the webinar is posted in our members area.
Sponsor a webinar!
We are always looking for corporate sponsors for our webinar series. Call Sarah if you’d like more information.