Xiang-Yuan Huang’s scientific contributions

We present the first description of the acoustic characters of the endangered Tengchong leaf litter toad (Leptobrachella tengchongensis), aiming to inform future ecological studies of the species and taxonomic studies in the genus Leptobrachella. A total of 1179 calls, belonging to 6 adults male individuals, were recorded using TASCAM DR-40 digital sound recorder from its type locality in May 2015 and then analyzed using Raven Pro v.1.6.1 software. The advertisement call of male L. tengchongensis consists of primary advertisement call and secondary advertisement call. The primary advertisement call is invariably composed of two notes and has a call duration of 61 ± 5 ms (23–87 ms, n = 1142). The secondary advertisement call is composed of 3–10 notes (mean 5.25 ± 1.41 notes/call, n = 37) with a call duration of 90 ± 6 ms (37–127 ms, n = 37). The mean inter-call interval is 212 ± 121 ms (88–1121 ms, n = 1092). An introductory note is absent in advertisement calls and the dominant of calls is 4.1–4.8 kHz (at 20 ℃). We discuss the interspecific and intraspecific variations on advertisement calls in L. tengchongensis and among Leptobrachella species, and provide a summary on the major acoustic characters of all Leptobrachella species occurring north of the Isthmus of Kra.

We report the first record of the poorly known slug-eating snake, Pareas vindumi from China: a female specimen collected from Dazhuba ranger station, Gaoligongshan National Nature Reserve, Tengchong city, Yunnan Province. The newly collected specimen represents only the second known specimen of the species and provides the first and valuable data on its morphological variation. Based on the new specimen, we revise the diagnostic characteristics of the species and provide additional data on its natural history and conservation status.

We presented the result of a systematic survey on the population size and distribution of the Endangered Gaoligong hoolock gibbon (Hoolock tianxing) in Houqiao Town, Tengchong City, Yunnan Province of China. A total of 15–18 individuals of H. tianxing in 5–6 gibbon groups and one solitary gibbon were recorded during the survey conducted in November 2019. The mean group size was 2.8 individuals (range 2–4) with a population density of 0.32–0.39 groups/km2. All groups contained an adult pair, and one or two immatures were observed in all but two. Mean dawn time was 07:21 h during the survey, and most vocalizations were produced between 1.0 and 2.5 h after dawn (75% of total song bouts), with an average song bout duration of 22.5 min (n = 12). Our result revealed that the Houqiao subpopulation of H. tianxing is of high conservation significance, since it is one of the largest subpopulations for the species in China and occurs in an unprotected area. The Houqiao forest is subjected to frequent human disturbance and the thriving agroforestry activity is degrading the forest integrity. Immediate conservation interventions are needed to safeguard the future of this important gibbon subpopulation. Discussions on the major threats to the species and relevant conservation recommendations are provided.

We present the results from a series of herpetological surveys conducted in the Tengchong Section of Gaoligongshan National Nature Reserve, Yunnan Province, China between April 2014 and November 2018. A total of 59 species of amphibians and reptiles (one salamander, 30 batrachians, four lizards, and 24 snakes) were recorded during the surveys including three newly described amphibian species and 17 new records for Tengchong, 10 of which also represent new generic records for the area. Natural history notes of some little-known species are presented. Our survey results clearly demonstrate that the herpetofauna diversity of this mountain range is still underestimated and warrants further systematic study.

We conducted field surveys on the mammalian diversity in the Tengchong Section of Gaoligongshan National Nature Reserve in Yunnan Province, China, using camera trap and transect method between April 2014 and May 2018. A total of 46 identifiable mammal species were recorded, including one new record for China and nine new species for the Tengchong County. Of the 46 species, nine are globally threatened (three Endangered and six Vulnerable) and six are Near Threatened on the IUCN Red List of Threatened Species. Species richness of most mammal groups in Tengchong remains high compared to similar sites in neighbouring countries; however, encounter rates for species vulnerable to high hunting pressures were quite low and large carnivores, except the Asiatic Black Bear, were either extirpated or at critically low numbers. Future surveys should cover a wider elevation range and a variety of microhabitats to increase the probability of detecting the species not yet recorded. To enhance the conservation value of the reserve for the diverse mammalian community, poaching and livestock grazing should be further controlled; in addition, protection and restoration of low-altitude forests should be encouraged. Monitoring and research on selected flagship species should also be conducted.

In order to understand the male calls characteristics of the poorly known Leptobrachium tengchongense, field survey was conducted on 27th February 2018 in Dahetou Ranger Station of Gaoligongshan National Nature Reserve, Tengchong City of Yunnan, China, aiming to obtain the records of male calls during its breeding season. A total of 78 male calls, belonging to six adult male individuals, were recorded using a digital recorder (TASCAM DR-40); the calls were analyzed using the Raven Pro © v.1.5 software. The results show that, adult males of Leptobrachium tengchongense could make two different types of calls during the breeding season, namely advertisement call and combat call. Both are single-note calls, and all have a dominant frequency of 1.31﹣1.50 kHz. The combat calls are normally emitted when there are other males calling nearby, and its call duration is comparatively longer than those of advertisement calls (610 ± 187.0 ms vs. 147 ± 30.1 ms), and contains more pulses (28 ± 10.7 pulses/s vs. 15 ± 2.4 pulses/s). There are variations on the call duration and intercall-interval among six individuals, and these variation may correlate with body size; however, due to the limited sample size, more records are needed in order to clarify the relationship between the body size and its call characteristics. Based on the survey result, we also discuss the current two major threats, habitat degradation and human consumption on tadpoles, to the species and propose relevant conservation actions.

During recent surveys in Gaoligongshan Mountain Range, Yunnan Province of China, we collected specimens of Scutiger from montane stream area at an elevation of 3000 m. Subsequent study based on morphological, molecular and acoustic data reveals that the newly collected specimens represent an unknown taxon and is described herein: Scutiger tengchongensis sp. nov.. The new species can be distinguished from its congeners by a combination of the following characters: (1) relatively small size (adult males SVL 36.0–40.1 mm, n=8); (2) vomerine teeth absent; (3) dorsum with large prominent, conical-shaped and longitudinal tubercles; (4) large tubercles on dorsum covered by numerous tiny black spines in males in breeding condition; (5) a pair of pectoral glands and a pair of axillary glands present on the chest, and covered by dense tiny black spines in males in breeding condition; (6) pectoral gland about twice the size of axillary gland; (7) inner three fingers with black nuptial spines in males in breeding condition; (8) nuptial spines on first and second fingers larger than those on third finger; (9) black spines on the belly absent; (10) vocal sac absent; and (11) toes webbing rudimentary. The discovery of S. tengchongensis sp. nov. represents the southernmost record of the genus worldwide, and the new species is the smallest known member of the genus in body size.

We conducted surveys to estimate the current population and distribution of the recently described Gaoligong hoolock gibbon (Hoolock tianxing) in Yunnan Gaoligongshan National Nature Reserve Tengchong Bureau (TC-GLGS). The reserve supports the northernmost known population of the species in China. A total of 17–20 gibbons in 6–7 family groups were recorded in TC-GLGS in a population census conducted in 2016. The mean group size was 2.8–2.9 individuals (range 2–4) with a population density of 0.18–0.21 groups/km 2. All groups contained a single adult pair, and juveniles and/or infants were observed in all but two. Mean dawn time was 07:26 h during the survey, and vocalizations were concentrated in the first hour after dawn (57.9% of total song bouts), with an average song bout duration of 25.7 min (n = 19). Four other primate species occurred in sympatry with the gibbons in the study area, with Macaca arctoides and M. assamensis being the most abundant. TC-GLGS appears to support the single largest subpopulation of H. tianxing in China, but the population density was very low, despite the presence of large areas of healthy, closed-canopy forest, suggesting that the population may have been well below carrying capacity. The suppressed population size is a combined result of rampant hunting in the past, loss of lower elevation forest, and ongoing disturbance by cattle grazing in the remaining gibbon habitat. Long-term conservation challenges facing the Gaoligong hoolock gibbon in China include the prevention of poaching and disturbance, restoration of deforested areas <2,000 m asl, and the establishment of biological corridors between forest fragments. Translocation to areas contiguous with larger subpopulations should be considered for single groups in isolated forest fragments.