Spatial capture-recapture with multiple noninvasive marks: An application to camera-trapping data of the European...

Area of Science:

• Ecology
• Conservation Biology
• Wildlife Management

Background:

• The European wildcat (Felis silvestris) is a protected species in Switzerland with a recovering population.
• Accurate population density estimates are vital for effective wildcat conservation strategies.
• Previous wildcat density estimates in Switzerland are limited, with only one reliable study conducted.

Purpose of the Study:

• To develop and test a novel monitoring protocol for European wildcat populations using camera trapping.
• To present and apply a new spatial capture-recapture model that incorporates multiple noninvasive marks for improved individual identification.
• To estimate the population density of wildcats in the northern Swiss Jura Mountains.

Main Methods:

• A 100 km² camera trapping survey was conducted over 60 days in the northern Swiss Jura Mountains.
• Phenotypical wildcats were photographed, with 98 images suitable for individual identification.
• A novel spatial capture-recapture model within the R package "multimark" was utilized, incorporating bilaterally asymmetrical flank markings.

Main Results:

• 13 individual wildcats were identified, along with additional unmatched flank images.
• The developed spatial capture-recapture model estimated a wildcat density of 26 individuals per 100 km² of suitable habitat (95% credible interval: 17-36).
• The integrated model provided more precise and higher abundance estimates compared to single-sided analyses.

Conclusions:

• Spatial capture-recapture models utilizing multiple noninvasive marks enhance the monitoring of wildcat population status.
• The novel model offers a computationally efficient alternative to Bayesian methods for population density estimation.
• This study provides crucial data for implementing effective conservation actions for the European wildcat in Switzerland.