Integrating multiple sign types to improve occupancy estimation for inconspicuous species
Mia R Goldman1,2,3, Matthew Shinderman4, Mackenzie R Jeffress5
1Department of Natural Resources and Environmental Sciences University of Nevada - Reno Reno Nevada USA.
Ecology and Evolution
|May 17, 2023
Summary
A new multi-sign occupancy model improves wildlife occupancy estimates by accounting for varied detection reliability of different signs, like scat and calls, for elusive species such as the American pika.
Area of Science:
- Ecology
- Wildlife Conservation
- Statistical Modeling
Background:
- Standard occupancy models estimate species presence by accounting for observation errors like missed detections.
- Indirect signs (scat, tracks) improve survey efficiency for elusive species but introduce additional error sources.
- Previous models often simplify the detection process, potentially biasing occupancy estimates.
Purpose of the Study:
- To develop and apply a "multi-sign" occupancy approach to model detection processes separately for unique sign types.
- To improve occupancy dynamics estimates for inconspicuous species, using the American pika (Ochotona princeps) as a case study.
- To compare occupancy estimates and environmental driver influences across four detection models, from perfect detection to a full multi-sign model with false detections.
Main Methods:
- Developed a multi-sign dynamic occupancy model allowing separate detection processes for distinct sign types (scat, haypiles, calls, sightings).
- Modeled detection of each sign type as a function of climatic and environmental covariates.
- Compared results from four models: perfect detection, standard occupancy, multi-sign without false positives, and multi-sign with false positives.
Main Results:
- Occupancy estimates and environmental driver inferences were sensitive to the chosen detection model.
- Simplified models yielded higher occupancy estimates and turnover rates compared to the full multi-sign model.
- Environmental drivers, such as forb cover, showed stronger influence on occupancy in the full multi-sign model.
Conclusions:
- Unmodeled heterogeneity in the observation process can bias occupancy estimates and create uncertainty in covariate relationships.
- The multi-sign approach accounts for spatio-temporal variation in sign reliability, offering more realistic occupancy dynamics.
- This method is valuable for generating robust estimates for inconspicuous species where indirect signs are crucial.
Keywords:
American pikadetection probabilityfalse negativefalse positiveindirect signmulti‐signoccupancy modelpopulation dynamicsMore Related Videos
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