X.-Z. Yuan's scientific contributions

An investigation was conducted along an elevation gradient with 26 sampling sections in Hengduan Mountains to study the vertical distribution of butterflies in the Mountains. A total of 603 species belonging to 299 genera and 12 families were recorded, among which, Nymphal had the most richness and abundance, while Parnassiidae, Acraeidae, and Libytheidae had the least ones but were rare and precious. Along the elevation gradient, there was an obvious difference in the species composition and community diversity, manifesting a distinct vertical pattern. The vertical distribution of the butterfly communities could be divided into six zones, i. e., low montane farmland zone (I) , mantane subtropical evergreen broadleaf forest zone (II) , montane warm temperate evergreen and deciduous broadleaf mixed forest zone (III) , montane temperate coniferous and broadleaf mixed forest zone (IV) , montane cold temperate dark coniferous forest zone (V) , and alpine subfrigid shrub meadow zone (VI). The diversity index ranked in the order of II > I > III > IV > V > VI. Among the six zones, zone II had the most abundant vegetation types and the most complex topography, and had higher specie richness, individual number, and diversity index of butterfly than the other zones, being the most important ecological area needed to be protected in priority.