Bat Diversity in Cat Ba Biosphere Reserve, Northeastern Vietnam: A Review with New Records from Mangrove Ecosystem

Abstract

The Cat Ba Biosphere Reserve is internationally renowned for its spectacular karst landscape. It covers a large area with hundreds of limestone islands and various ecosystems including caves, tropical forests, and mangroves. However, previous surveys were only conducted in terrestrial ecosystems on Cat Ba Island. Therefore, bats inhabiting mangroves and the remaining islands did not receive attention from scientists up to 2014. To initially fill in the gaps, we conducted ten bat surveys between 2015 and 2020 with an emphasis on mangroves and previously unsurveyed islands. Bats were captured using mist nets and harp traps. Twenty-three species belonging to 13 genera of six families were recorded during the surveys. Of these, four species (Macroglossus minimus, Myotis hasselti, Phoniscus jagorii, Tylonycteris fulvida) are new to the reserve. Remarkably, 15 species belonging to seven genera of five families were captured in mangrove, which is the highest species diversity for bats reported from any mangrove area in mainland Southeast Asia. Based on results from the surveys and literature review, we here provide the most updated bat diversity of the reserve with confirmed records of 32 bat species belonging to 16 genera of six families. Historical records of each species in the literature were reviewed. Two species, Scotophilus heathi and Scotophilus kuhlii, are unconfirmed because of unclear evidence in previous publications. Results of this study indicated that the mangrove ecosystem is important for bats but still poorly studied in Cat Ba Biosphere Reserve and Vietnam as a whole. In addition, morphological measurements, echolocation data, distributional records, and conservation status of each species are also given in this paper for potential research and conservation campaigns in the future.

First Records of Bats (Mammalia: Chiroptera) from the World’s Largest Cave in Vietnam

“…The hindfoot with long claws and other morphological features of the three Myotis individuals captured at Son Dong Cave fit the identification of M. pilosus. Echolocation call structure and frequency of M. pilosus in Son Dong Cave are also similar to those of the species from other areas of Vietnam [13,15,16]. The external characteristics and measurements of two other Myotis individuals are almost identical to those of Myotis muricola (Figure 3; Table 1).…”

“…Vietnam has 19 Myotis species including M. pilosus and M. muricola [13]. Myotis pilosus is distinguishable from other Myotis species in Vietnam by its body size with a forearm length of over 50 mm and a hindfoot including claws that is approximately three-quarters of the tibia length [9,13,15,16,22]. The hindfoot with long claws and other morphological features of the three Myotis individuals captured at Son Dong Cave fit the identification of M. pilosus.…”

“…Externally, the posterior nose leaf of A. dongbacanus is more fleshy than that of A. stoliczkanus [13] and the upper canine of A. dongbacanus is longer than that of A. stoliczkanus [13]. To date, A. dongbacanus is only known in karst areas in northern Vietnam, whereas A. stoliczkanus is a widespread species with records from various areas and a wide range of ecosystems in northern and central Vietnam [9,13] as well as Phong Nha-Ke Bang National Park over the past decades [9,[14][15][16]23]. Therefore, the characteristics of the posterior noseleaf and echolocation calls of the captured and observed individuals in Son Doong Cave can be assigned to A. stoliczkanus.…”

“…Echolocation calls recorded in natural habitats were carefully compared with the calls of the captured bats when they were released for identification. All recorded calls were also compared with an unpublished database of the first author and data in selected publications [12][13][14][15][16][17][18][19][20][21].…”

Diversity Aspects in Bats: Genetics, Morphology, Community Structure

“…This is especially important when it comes to unique areas such as isolated islands. Based on new data, Vu Dinh Thong et al [13] provide an overview of the bat fauna of the Cat Ba archipelago. Previous surveys on these islands were conducted in the inner areas of Cat Ba Island.…”