Introduction and Implementation of Harp Traps Signal a New Era in Bat Research

Abstract

Flight and nocturnal behavior hinder direct observation of bats, limiting our knowledge of their ecology, thus creating the impetus for effective capture techniques. Mist nets have been used to trap bats for nearly a century, but are less effective under certain scenarios, including when nets are easily detected and avoided by many aerial and gleaning insectivores foraging in clutter and edge space. The invention of the harp trap gave access to these “mist net avoiders”, signaling a new era in bat research. First announced at the second North American Symposium for Bat Research (NASBR), a major modification popularized the use of harp traps among bat scientists. We conducted a global review of the literature and implemented two bibliometric analyses to reveal the contribution of harp traps to bat research. First, we show that globally, harp trap deployment is rising steeply, with the highest number of published harp trap studies reported from North America, Southeast Asia and Oceania (mostly Australia). Harp trap use is low in Central/South America, likely driven by a research emphasis on species of Phyllostomidae (readily captured in mist nets). Harp traps are rarely used in Africa except southern Africa and Madagascar. Our second bibliometric analysis focused on the impact of harp traps as a tool contributing to species discovery in Southeast Asia where it has contributed to over 50% of all species descriptions in the region by 2014. In sum, we show that the invention and implementation of harp traps has advanced our knowledge of bat taxonomy, diversity patterns, community assembly and ecology, upending dogmas and misconceptions, all with conservation implications. However, regional shortfalls in harp trap deployment is evident in Central, East and West Africa, as well as the Neotropics. Being species rich, these regions represent new frontiers for the use of harp traps that will likely lead to many discoveries.