Qisen Yang

Conservation status and causes of decline of musk deer (Moschus spp.) in China

Five species of musk deer (Forest musk deer Moschus berezovskii, Alpine musk deer M. sifanicus, Black musk deer M. fuscus, Himalayan musk deer M. chrysogaster and Siberian musk deer M. moschiferus) occur throughout 17 provinces in China, and all were listed in the second category of the Chinese State Key Protected Wildlife List in 1998. Among these species, the Forest musk deer has the widest distribution, and its population is estimated at about 100,000–200,000 individuals in the wild. Additionally, there are about 100,000 Alpine musk deer and 2000 Siberian musk deer. As for the Black musk deer and Himalayan musk deer, which occur only in parts of Yunnan Province and Tibet, their populations remain unknown but they can be estimated to be rare due to their narrow and limited distribution. Furthermore, there are some 1900 musk deer kept in farms in China. Generally, the musk deer population has been declining due to over-hunting for musk and to loss of habitats. However, the Chinese government is greatly concerned with wildlife protection today. A series of laws and regulations have been launched and many natural reserves and national parks have been established as refuges for this animal, most of which, are within the musk deer’s range, and should have positive effects for musk deer conservation. # 2002 Elsevier Science Ltd. All rights reserved.

Evolutionary History of Lagomorphs in Response to Global Environmental Change

Although species within Lagomorpha are derived from a common ancestor, the distribution range and body size of its two extant groups, ochotonids and leporids, are quite differentiated. It is unclear what has driven their disparate evolutionary history. In this study, we compile and update all fossil records of Lagomorpha for the first time, to trace the evolutionary processes and infer their evolutionary history using mitochondrial genes, body length and distribution of extant species. We also compare the forage selection of extant species, which offers an insight into their future prospects. The earliest lagomorphs originated in Asia and later diversified in different continents. Within ochotonids, more than 20 genera occupied the period from the early Miocene to middle Miocene, whereas most of them became extinct during the transition from the Miocene to Pliocene. The peak diversity of the leporids occurred during the Miocene to Pliocene transition, while their diversity dramatically decreased in the late Quaternary. Mantel tests identified a positive correlation between body length and phylogenetic distance of lagomorphs. The body length of extant ochotonids shows a normal distribution, while the body length of extant leporids displays a non-normal pattern. We also find that the forage selection of extant pikas features a strong preference for C3 plants, while for the diet of leporids, more than 16% of plant species are identified as C4 (31% species are from Poaceae). The ability of several leporid species to consume C4 plants is likely to result in their size increase and range expansion, most notably in Lepus. Expansion of C4 plants in the late Miocene, the so-called ‘nature’s green revolution’, induced by global environmental change, is suggested to be one of the major ‘ecological opportunities’, which probably drove large-scale extinction and range contraction of ochotonids, but inversely promoted diversification and range expansion of leporids.

The effect of the Qinghai-Tibet railway on the migration of Tibetan antelope Pantholops hodgsonii in Hoh-xil National Nature Reserve, China

The Tibetan antelope or chiru Pantholops hodgsonii is endemic to the Tibetan plateau and was once abundant over vast areas of high elevation grassland habitat. During the 20th century, however, the population declined greatly in numbers. Hunting used to be the main threat to this species but recent actions by the government and wildlife protection organizations have brought this under control. With the development of north-west China, conflicts between development of transportation facilities and conservation have become more acute, and heavy traffic on the Golmud-Lhasa highway and the construction of the Qinghai-Tibet rail- way across key migration corridors have disturbed the migration of Tibetan antelopes. During June to August 2003 and 2004 we monitored the movement of Tibetan antelopes across the railway and highway and recorded their passes at wildlife crossing structures, which was the first use of such structures in China. Our results show that the efficiency of passages greatly improved between 2003 and 2004, and that use of wildlife corridors was affected by the structure of the passage, presence of wolves, recovery of vegetation following damage during construction, and other factors. The disturbance to mi- gration of Tibetan antelopes included infrastructure, human activities, road traffic, construction of the railway and so on. The impact of infrastructure, especially trans- portation development, on the habitat and migration of Tibetan antelopes are the main factors that threaten this species now and in the future.

The temporal estrous patterns of female alpine musk deer in captivity

From 1996 to 2000, we collected data about rutting habits of captive Alpine musk deer (Moschus sifanicus) in the Breeding Center of Alpine Musk Deer (BCAMD) located in the Xinglongshan National Nature Reserve of China. We examined the temporal rutting patterns to determine the timing and synchrony of estrus. From 1997 to 2000, the temporal estrous patterns remained relatively constant across the years but in 1996, the animals entered estrus later and the estrous season was longer than in other years possibly due to the animal being transported in that year. In total, the estrus period of captive musk deer in BCAMD occurred seasonally during 3 months of the year, but 66% of mating occurred in a month from 21 November to 21 December. The total estrous season (when 75% of mating occurred) was 36 days. When the possible factors affecting the temporal estrous patterns were analyzed, it appeared that the rutting of females was influenced by both social and seasonal factors. There were significant differences among the temporal estrous patterns of animals in different rows of enclosures, probably because of keeper effects and social interactions among females within a row of enclosures. Female age can affect timing of estrus: females older than 5.5 years entered estrus earlier than younger age classes. The reproductive success in the previous year was not related to rutting patterns. The temporal estrous patterns were not significantly different between the captive females of the wild-caught deer and their firstgeneration offspring. Females with more estrous cycles were less likely to enter estrus earlier than those with one or two cycles. # 2003 Elsevier Science B.V. All rights reserved.

Tracing the Origin and Diversification of Dipodoidea (Order: Rodentia): Evidence from Fossil Record and Molecular Phylogeny

Dipodoidea are a diverse rodent group whose earliest known record is from the Middle Eocene. The evolution and diversification of this superfamily have been documented by fossils and comparative morphology, but have not yet been studied from the perspective of molecular phylogeny. This study is the first attempt to reconstruct an extensive phylogeny of Dipodidae and estimate divergence times based on a nuclear gene coding for interphotoreceptor retinoid-binding protein. We found that there is a wide measure of agreement with the fossil record. Each of the three ecological groups of the extant Dipodoidea (sicistines, zapodines, and jerboas) has its distinctive distribution; the distribution patterns have been shaped by the dispersal events. The key events of paleogeographic distribution coincided with major paleoenvironmental events in the Cenozoic. The first important diversification phase occurred during the period from the Oligocene to Early Miocene, when global climate underwent major changes beginning with the Eocene/Oligocene boundary. The second adaptive radiation occurred within jerboas and was associated with the expansion of open habitat starting with the late Middle Miocene. The diversification of jerboas can be correlated with habitat changes in response to global and regional climatic events.

Molecular phylogeny and the underestimated species diversity of the endemic white-bellied rat (Rodentia: Muridae: Niviventer) in Southeast Asia and China

The white‐bellied rat, Niviventer, is a genus endemic to Southeast Asia and China. However, the interspecific phylogenetic relationships and species diversity of this genus remain poorly understood. In the present study, single and multi‐locus analyses were performed. Phylogenetic reconstruction on Cytochrome b (512 individuals, including data from Genbank) revealed five major clades with approximately 35 operational taxonomic units (OTUs), a number twice the existing taxonomy. The first clade (N. langbianis species group) was the earliest diverged. The second clade (N. fulvescens species group) diverged in Southeast Asia, the south and lower altitude regions of the Hengduan Mountains, and Southeast China. The third clade (the N. eha species group) is endemic to high altitudes in Northwest Yunnan and the central region of Himalaya. The fourth clade (the N. andersoni species group), is mainly confined to alpine regions of the Hengduan Mountains. The fifth clade (N. confucianus species group) is mainly distributed in the north and higher altitude regions of eastern Himalaya, the Hengduan Mountains and Taiwan, with the complex also invading central and northern China. Results from the combined dataset of four genes (Cytochrome b, Cytochrome oxidase subunit I, the D‐loop sequence of the mitochondrial genome and the first exon of the nuclear interphotoreceptor retinoid binding protein) for 82 representative individuals from China generally coincide with the result of the single gene, with 12 OTUs identified. These results provide a preliminary framework for the existing classification of this highly diversified genus. The divergence time of Niviventer based on the four gene topology was dated to the late Miocene ~6.41 Ma. Significant differences were detected in the general body form changes among these units based on voucher specimens. Moreover, geometric morphometric analysis of the cranium shape of voucher specimens indicated significant differences among five major species groups. Shape divergence of the cranium among several OTUs within the N. confucinaus complex is also significant. Our results provide further evidence for rapid and highly underestimated diversification of Niviventer both in genetics and morphology.

Comparison of phylogeographic structure and population history of two Phrynocephalus species in the Tarim Basin and adjacent areas

An aridification of the Tarim Basin and adjacent areas since middle Pleistocene has produced significant genetic structuring of the local fauna. We examined the phylogeographic patterns, population structure and history of Phrynocephalus axillaris and Phrynocephalus forsythii using a mitochondrial fragment ND4-tRNA(LEU). Phylogenetic hypotheses were constructed using maximum parsimony and Bayesian inference, and the divergence times of major lineages were estimated by BEAST. Population structure and history were inferred by nested clade analysis, neutrality tests, mismatch distribution, and isolation by distance analysis. The two species might have experienced different evolutionary history throughout their current distribution. For P. forsythii, a vicariant event, as a consequence of geological isolation and desert expansion, might have produced the significant divergence between the Tarim and the Yanqi populations. For P. axillaris, populations of the Yanqi, Turpan and Hami Basins might have been established through dispersal during demographic expansion. Climatic fluctuations caused alternate expansion and shrinkage of rivers and oases several times, which likely led to habitat fragmentation for both species. Interaction between vicariance, dispersal and habitat fragmentation produced the current distribution and genetic diversity. The observed difference between the two species may be due partially to their different reproductive modes (ovoviviparous vs. oviparous).

Molecular phylogeny and biogeography of Petaurista inferred from the cytochrome b gene, with implications for the taxonomic status of P. caniceps, P. marica and P. sybilla.

The polymorphic genus Petaurista includes a group of diverse species and subspecies that are adapted for gliding and arboreal life. This morphological diversity has resulted in taxonomic discrepancies, and molecular phylogenetic studies have been limited by taxon sampling. To clarify this controversial taxonomy, we used the cytochrome b gene to reconstruct the phylogeny to obtain a more accurate picture of the evolutionary relationships, species differentiation and divergence pattern of Petaurista. The results revealed a significant inconsistency between taxonomic designations, phylogeny and genetic distances. When 6 recognized species were included, species delimitation revealed 15 putative species, a finding that warrants a comprehensive morphological diagnosis and a re-assessment of the species status. The validity of P. caniceps and P. marica was discussed. An estimation of the molecular divergence time demonstrated that the diversification and speciation of Petaurista began during the later Miocene and may have been affected by the uplifting of the Qinghai-Tibet plateau and subsequent climate change.

Geometric morphometric study of the skull shape diversification in Sciuridae (Mammalia, Rodentia).

It is generally accepted that the high phenotypic diversity of mammals is a combined result of developmental constraint and ecological adaptation, although the influence of these endogenous and exogenous factors varies in different mammal groups. The rodent family Sciuridae represents an ideal candidate for examining phenotypic diversity in relation to phylogeny and ecological adaptations. In the present study, we investigate the effects of phylogeny and lifestyle on the skull shape in different species of Sciuridae by applying geometric morphometric methods. In addition, we investigate the importance of allometry on sciurid skull shape, because results from geometric morphometrics sometimes dispute those of traditional morphometry. Here, we identify significant associations between patristic distances obtained from molecular phylogeny and shape distances in all 3 views of the cranium and the lateral view of the mandible. Multivariate regression demonstrates that shape differences among lifestyle categories are substantial, especially in the dorsal and ventral structures after the influence of phylogeny is taken into account. Allometry plays an important role in the shape variation, although its importance on different skull structures varies. Our results indicate that complex structures of this highly diverse mammal group, which occupies different niches, are affected by ecological factors and developmental constraint.

The Evolution and Paleobiogeography of Flying Squirrels (Sciuridae, Pteromyini) in Response to Global Environmental Change

Flying squirrels are strictly arboreal squirrels adopting a special gliding form of locomotion. This group of animals has a long history that has mirrored the vicissitude of forests. The discrepancy in the distribution between fossils and extant species indicates a mysterious evolution history requiring further exploration. This study compiles the worldwide fossils of Pteromyini to the species level in order to reproduce the spatiotemporal distribution pattern of flying squirrels and deduce the ancestral distribution according to dispersal-vicariance analysis of a phylogeny of the extant species. In addition, we reconstruct the paleoenvironmental background and find that flying squirrels probably originated in the Oligocene–Miocene transition from Europe and immediately dispersed to Asia and North America. Influenced by glaciation, CO2 reduction, geologic movements and the Paratethys retreat, the Northern Hemisphere underwent climate deterioration and grassland expansion during the late Miocene, and thus the diversity of Pteromyini dramatically decreased. The uplift of the Tibet Plateau in addition to the strengthened Asian monsoons intensified the aridity in central Asia, but brought sufficient water to the densely forested regions of South and Southeast Asia. These forests are likely both refugia and diversification center for flying squirrels during glacial periods in the Quarternary. The subsequent connection and separation events among these heterogeneous habitats has probably been a driving force in the speciation of flying squirrels. Based on this work, we predict a bleak future for the flying squirrels, one which is closely associated with the fate of forests in Asia.