An invasive‐native mammalian species replacement process captured by camera trap survey random encounter models

By Anthony Caravaggi, Marco Zaccaroni, F. Riga, S. Schai-Braun, J. Dick, W. Montgomery, N. Reid. 2016

94 citations recorded by the source corpus.

Camera traps are used to estimate densities or abundances using capture‐recapture and, more recently, random encounter models (REMs). We deploy REMs to describe an invasive‐native species replacement process, and to demonstrate their wider application beyond abundance estimation. The Irish hare Lepus timidus hibernicus is a high priority endemic of conservation concern. It is threatened by an expanding population of nonnative, European hares L. europaeus, an invasive species of global importance. Camera traps were deployed in thirteen 1 km squares, wherein the ratio of invader to native densities were corroborated by night‐driven line transect distance sampling throughout the study area of 1652 km2. Spatial patterns of invasive and native densities between the invader's core and peripheral ranges, and native allopatry, were comparable between methods. Native densities in the peripheral range were comparable to those in native allopatry using REM, or marginally depressed using Distance Sampling. Numbers of the invader were substantially higher than the native in the core range, irrespective of method, with a 5:1 invader‐to‐native ratio indicating species replacement. We also describe a post hoc optimization protocol for REM which will inform subsequent (re‐)surveys, allowing survey effort (camera hours) to be reduced by up to 57% without compromising the width of confidence intervals associated with density estimates. This approach will form the basis of a more cost‐effective means of surveillance and monitoring for both the endemic and invasive species. The European hare undoubtedly represents a significant threat to the endemic Irish hare.

Subfields: Ecological Modeling, Ecology

View Paper: https://www.semanticscholar.org/paper/bd224acde672183e2a8bcc504d4ab91c1588ea9a

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Ecological Modeling

In Ecology

Citations in the corpus

Modelling the influence of biotic factors on species distribution patterns (2016, unknown): “…between L. granatensis and L. europaeus (Gortazar et al ., 2007), L. europaeus and L. timidus (Thulin, 2003; Reid & Montgomery, 2007; Reid, 2011; Caravaggi et al. , 2014; 2016) and O. cuniculus and L. timidus (though this latter relationship has not been empirically documented their ranges show…”
A simple method for estimating the effective detection distance of camera traps (2017, methodology): “This method was recently simplified by the use of a photograph of a grid of markers taken after each camera deployment to estimate detection distance and angle using image processing software (Caravaggi et al. 2016).”
Estimating animal density without individual recognition using information derivable exclusively from camera traps (2018, unknown): “…movement speed, only a handful of studies have applied the REM to date (Anile, Ragni, Randi, Mattucci, & Rovero, 2014; Balestrieri et al., 2016; Caravaggi et al., 2016; Carbajal- Borges, Godínez- Gómez, & Mendoza, 2014; Cusack et al., 2015; Manzo, Bartolommei, Rowcliffe, & Cozzolino, 2012;…”
Distance sampling with camera traps (2017, methodology): “We recommend that researchers measure angles as well as distances to detected animals (e.g. Caravaggi et al. 2016), and test for departures from the uniformity assumption at increasing angles as part of their exploratory analysis.”