Capture success higher near roads for san clemente island foxes

Abstract

Recently, island fox (Urocyon littoralis) populations on 4 of 6 California Channel Islands (USA) were greatly reduced by colonizing golden eagles (Aquila chrysaetos) and a suspected outbreak of disease, creating concern for subspecies on all islands. Consequently, efforts of live‐trapping foxes for research, monitoring, and vaccination has increased. Despite increased trapping efforts, evaluation of factors that influence capture success has not been conducted. We examined capture success of island foxes at 85 random trapping locations on San Clemente Island during 170 trap‐nights during 2006–2007. We captured 98 island foxes, and found that traps placed ≤10 m from primary roads had higher overall capture success (i.e., 1.52 times more likely to capture foxes) than traps placed at random locations throughout the study area. We found no evidence to suggest that the density of edges between land‐cover types (i.e., sum length of edges per 100‐m buffered area [m/m2]), nightly temperature, proportions of land‐cover, or type of attractant tested (n = 3) affected capture success. All attractants captured similar proportions of sex and age classes of foxes. Our findings suggest that future trapping efforts would have the most success if conducted along roads. © 2013 The Wildlife Society.

Island fox spatial ecology and implications for management of disease

“…Island foxes occur in some of the highest population densities recorded for any canid (Roemer et al ) but it is unknown whether population density or rates of contact differ between the road and non‐road sub‐populations on San Clemente Island. Snow and Andelt () reported that capture success for foxes was highest near roads on San Clemente Island, suggesting perhaps a higher density of foxes near roads. Increased contact among species subpopulations has been reported to increase the prevalence, incidence, and rate of spread of canine distemper and rabies in the overall population (Cleaveland et al , Woodroffe et al ).…”

Predator Presence and Vegetation Density Affect Capture Rates and Detectability of Litoria aurea Tadpoles: Wide-Ranging Implications for a Common Survey Technique

“…Identifying factors that affect the success of a sampling technique is important to minimise bias that results from non-random and non-independent sampling in order to make accurate inferences about population dynamics. Minimising bias is particularly important for population monitoring, which aims to detect trends in populations [ 2 ]. Knowledge of any bias associated with sampling techniques is crucial for confidently drawing conclusions about population trends.…”