Comparative Study on Blowfly-Derived DNA and Camera Trapping in Assessing Mammalian Diversity in Subtropical Forests

Mammalian DNA derived from invertebrates (iDNA), including blowfly iDNA, is an alternative tool to conventional camera trapping in assessing mammalian diversity. The method has been used in tropical mammal surveillance but no attempt has been made to compare the efficacy of blowfly iDNA and camera trapping for monitoring mammal diversity in subtropical forests. We compared the blowfly iDNA monitoring with camera trapping to assess mammal diversity in the subtropical Jiulongfeng Nature Reserve (JLF), China, over a one-month period. The camera traps captured 2508 animal photos of 11 species belonging to four orders, eight genera, and eight families, whereas the blowfly iDNA method successfully detected ten species from six orders, eight genera, and eight families in JLF. Both methods were complementing each other instead of competing due to the low overlaps of mammal species detected. Of the total number of mammal species listed in JLF's threatened list, 40% and 10% were detected through camera traps and blowfly iDNA methods, respectively. The estimated species richness curves indicated that combining camera traps and blowfly traps would increase the detection of mammal species. The strategy would significantly contribute to mammalian diversity surveillance and conservation programs in the tropical and subtropical forests.