Snap happy: camera traps are an effective sampling tool when compared with alternative methods

Camera traps have become a ubiquitous tool in ecology and conservation. They are routinely deployed in wildlife survey and monitoring work, and are being advocated as a tool for planetary-scale biodiversity monitoring. The camera trap's widespread adoption is predicated on the assumption of its effectiveness, but the evidence base for this is lacking. Using 104 past studies, we recorded the qualitative overall recommendations made by study authors (for or against camera traps, or ambiguous), together with quantitative data on the effectiveness of camera traps (e.g. number of species detected or detection probabilities) relative to 22 other methods. Most studies recommended the use of camera traps overall and they were 39% more effective based on the quantitative data. They were significantly more effective compared with live traps (88%) and were otherwise comparable in effectiveness to other methods. Camera traps were significantly more effective than other methods at detecting a large number of species (31% more) and for generating detections of species (91% more). This makes camera traps particularly suitable for broad-spectrum biodiversity surveys. Film camera traps were found to be far less effective than digital models, which has led to an increase in camera trap effectiveness over time. There was also evidence from the authors that the use of attractants with camera traps reduced their effectiveness (counter to their intended effect), while the quantitative data indicated that camera traps were more effective in closed than open habitats. Camera traps are a highly effective wildlife survey tool and their performance will only improve with future technological advances. The images they produce also have a range of other benefits, for example as digital voucher specimens and as visual aids for outreach. The evidence-base supports the increasing use of camera traps and underlines their suitability for meeting the challenges of global-scale biodiversity monitoring.

An evaluation of hair-snaring devices for small-bodied carnivores in southwest China

Human population growth is a major threat to the biodiversity of mammals in China. Rapid development of infrastructure, pollution, and poor enforcement of environmental laws in China have altered the landscape and accelerated the extinction rates of mammals. To maintain biodiversity and conserve the mammals of China, it is essential to develop monitoring protocols for species of concern that are efficient, cost-effective, and current. It is now common practice for ecologists to survey mammals of interest using noninvasive sampling methods. These sampling techniques are affordable, require no handling of the target animals, and generally yield large samples. In China, such sampling methods have rarely been used and evaluated. For this study, we recorded the behavior of masked palm civets ( Paguma larvata ) and Siberian weasels ( Mustela sibirica ) to determine their relative preference for using different hair-snaring devices and evaluated the effectiveness of each device at collecting hair. Our goal was to determine which genetic sampling method(s) should be used to study masked palm civets and Siberian weasels in the future in Southwest China. In March–June of 2014, we monitored 13 hair-snare stations throughout the Main Valley of Laohegou Nature Reserve, Sichuan Province, China. Genetic analysis revealed that we collected 373 hair samples from civets and 47 hair samples from weasels over 104 and 26 sessions, respectively. Both civets and weasels seemed to prefer lure sticks to ground cubbies; however, the latter were more effective at collecting civet hair. Although glue sheets from lure sticks collected large samples of guard hair (> 10), no device in its current design was consistently effective at collecting weasel hair. We suggest researchers in Southwest China use ground cubbies as described in this study to collect hair from masked palm civets and test other cubby designs (e.g., longer gun brushes or smaller in size) for collecting hair from Siberian weasels.

人口增长是中国哺乳动物多样性危机的主要根源之一。在中国，基础建设的快速发展、环境污染，加之环境执法力度不足造成了哺乳动物的栖息地的退化，加速了动物的灭绝速率。为了维持生物多样性水平和保护中国的哺乳动物，有必要针对受关注的物种开发有效、低成本且通用的监测方法。现在，非损伤性取样方法正被生态学家普遍应用于哺乳动物的调查中。这些调查技术在成本上易于接受，不需要接触目标动物，并且通常可以得到大量可靠的样本。在中国，非损伤性取样方法的应用和评估还较少。本研究中，我们在四川省老河沟自然保护区评估了花面狸和黄鼬对毛发陷阱的访问偏好及陷阱收集动物毛发的有效性；目标是选出有效地遗传取样方法用于将来对花面狸和黄鼬的研究。从2014年3月到6月，我们在保护区主要山谷内设置了13个毛发陷阱站，在收集野生动物的毛发同时使用红外相机记录动物访问陷阱站时的行为。我们发现，相比于设置在地面的小室陷阱，花面狸和黄鼬都更喜欢访问直立的木桩陷阱，但是，小室陷阱能够更有效地收集花面狸的毛发。尽管固定有粘性薄片的木桩 陷阱能够少量收集带有直针毛的毛发（>10根）,但是我们评估的毛发陷阱都不能有效地收集黄鼬的 毛发。根据研究，我们建议研究人员在中国西南可以应用固定有枪刷的小室陷阱（如本研究中所评估的）收集花面狸的毛发，而用更长的枪刷，或者更小的小室陷阱，并固定粘性薄片收集黄鼬的毛发。

A comparison of the effectiveness of camera trapping and live trapping for sampling terrestrial small-mammal communities

Context. There is an increasing reliance on the use of camera-trap technologies for surveys of medium to large terrestrial mammals. Camera trapping may, however, also have significant applications for broad-scale surveys of small mammals. Aims. The present study aims to compare results from camera-trapping surveys to those of the more traditional live-trapping techniques. Specifically, it aims to test the effectiveness of the techniques for detecting species, and the cost effectiveness of both approaches. Methods. Surveys were conducted across 36 sites in the Grampians National Park, Victoria, Australia, between April and July 2009. At each site, independent surveys were conducted for small mammals by using a combination of Elliot and cage trapping, then camera trapping. Results for the two different approaches were compared for both their ability to generate small-mammal presence data and their cost effectiveness. Key results. Camera-trapping surveys of 36 sites in the Grampians National Park compared favourably with those of live-trapping surveys. Similar species were detected across the sites, and camera trapping was a considerably more cost effective than live trapping. Conclusions. Camera-trapping surveys of small terrestrial mammals may provide a new and cost-effective technique for surveying terrestrial small mammals. This is particularly the case when presence data are the main requirement of the survey, with no requirement to capture and tag animals. Implications. Given the cost-effective nature of camera trapping, there is potential to use this approach to increase the level of replication and spatial coverage of small-mammal surveys. Improving the replication and spatial coverage of studies has the potential to significantly increase the scope of research questions that can be asked, thus providing the potential to improve wildlife management.