Effectiveness of different types of hair traps for brown bear research and monitoring

Abstract

Non-invasive sampling by hair-trapping is increasingly used worldwide in wildlife research. Despite this rise and the potential of hair samples for ecology and conservation studies, the relative performance of hair collection devices has been rarely tested. Here, we compare the effectiveness of five types of hair traps for brown bears Ursus arctos in the Carpathian Mountains (SE Poland) and test the effects of trap type, season, number of days elapsed since trap installation and trap features on the trapping success in order to provide recommendations for optimal sampling in future studies. The trap types were corral, path-trap, “smola”(beechwood tar) tree-trap, turpentine tree-trap and natural rub. In 2010, we collected 858 hair samples during 2330 inspections of 175 hair traps and found that the most effective traps were smola tree-traps (mean percentage of successful inspections ± SD: 30.2% ± 26.0) and natural rubs (50.8% ± 16.7). Based on this finding, over the following 2 years we focused on 24 smola tree-traps and eight natural rubs. During this long-term survey (2010–2012, 969 inspections, 1322 samples collected) the trapping success increased with time and smola tree-traps achieved similar effectiveness to natural rubs (45.5% ± 29.7 and 45.9 ± 23.4, respectively). We show that when baiting smola tree-traps ten weeks prior to research or monitoring, sampling effectiveness can reach up to 30%. Taking into account the logistical and methodological constraints associated with detecting and using natural rubs for a proper survey design, we recommend using smola tree-traps baited in advance for hair sampling in wildlife studies.

Brown bear communication hubs: patterns and correlates of tree rubbing and pedal marking at a long-term marking site

“…Male bears mark all year round but with a main peak during the mating season, a period of intense competition. This pattern has also been found at rubbing trees, both natural and artificially created to collect bear hairs (i.e., tree hair traps), in different ecosystems ( Green & Mattson, 2003 , Karamanlidis et al, 2010 ; Sato et al, 2014 ; Berezowska-Cnota et al, 2017 ; Lamb et al, 2017 ).…”

“…Bears choose specific trees in places that are well situated for the passage of other individuals ( Green & Mattson, 2003 ; Sato et al, 2014 ). At these sites there is an association between different communication behaviors, with marking behaviors triggering the subsequent sniffing and marking of later visitors ( Berezowska-Cnota et al, 2017 ). Nevertheless, these sites are not uncommon.…”

Peer Review #2 of "Brown bear communication hubs: patterns and correlates of tree rubbing and pedal marking at a long-term marking site (v0.1)"

“…This pattern has also been found at rubbing trees, both natural and artificially created to collect bear hairs (i.e. tree hair traps), in different ecosystems (Green & Mattson 2003, Karamanlidis et al 2010, Sato et al 2014, Berezowska-Cnota et al 2017, Lamb et al 2017.…”

Population genetics of the main population of brown bears in southwest Asia

“…It was recently shown that hair samples obtained from rubbing trees perform better for genotyping than hair samples collected by other noninvasive methods, such as hair from corral traps ( Berezowska-Cnota et al, 2017 ). We similarly observed that hair samples from rubbing trees performed best among the hair sample sources used in our study ( Table 4 ).…”