No abstract

Acoustic triangulation is a unique, relatively noninvasive monitoring approach that can inform our understanding of a species’ distribution in time and space. Acoustic triangulation relies on standard triangulation techniques to determine the location of an acoustic event. Howl surveys are frequently used to survey wolves (Canis lupus) and other canids. We evaluated the efficacy of acoustic triangulation for estimating the location of wolves. We measured precision and accuracy of acoustic triangulation using an experimental mock howl survey and field data collected with wild wolves in northern Wisconsin, USA (2014–2018). Precision of acoustic triangulation was similar to triangulation with ground‐based radiotelemetry for both pooled data and individual wolves at specific times, although the 2 techniques did not result in similar predicted locations. Distance from the howl source was the most consistently significant factor influencing the efficacy of acoustic triangulation. Error ellipse size was 33 times smaller at distances <1 km. Wind speed also reduced the accuracy of acoustic triangulation for mock howl surveys. Precision for modified howl surveys with wild wolves improved with the number of bearings. We estimated a mean bearing error of 13.2° (±2.1, 95% CI) for single bearings and a maximum distance of 1.76 km (range = 0.96–1.76 km;  = 1.41 km) detection for audible anthropogenic howls. Such information can be applied to howl survey data to generate more fine‐scale location information for wolf‐pack home sites. Acoustic triangulation of wolves can provide high‐quality location information in areas where wolves are not monitored with radiocollars. © 2020 The Wildlife Society.

Island biogeography theory is a foundational ecological concept that describes how island or habitat patch size and isolation predict biodiversity, but few have studied how the effects of island biogeography vary with life history characteristics of temperate mammal communities. From 2014 to 2020, we surveyed volant and nonvolant mammals within the Apostle Islands archipelago (Wisconsin, USA) using camera trapping, live trapping, and acoustic monitoring. We used linear regression and information-theoretic model selection to evaluate the effects of island size and isolation on indices of biodiversity. We also examined the effects of life history characteristics (i.e., body mass, winter inactivity) on the relative abundance and distribution of each species on the islands and the mainland. For volant mammals, island size and isolation were not associated with any metrics of diversity. We found island size was positively associated with nonvolant mammal species richness and diversity, but not species evenness. Island isolation was not a significant predictor for small nonvolant mammal diversity, although both size and isolation appeared to influence island biogeography of medium-large nonvolant mammals. We also found that the interaction between winter inactivity and body mass influenced the vagility of nonvolant mammals in the archipelago. Our results suggest that life history characteristics are important in mediating species responses to biogeography, supporting the dispersal-limitation nonequilibrium view of island biogeography theory, particularly for nonvolant mammals.