Examining the Pattern of Character Displacement of Two Sympatric Agamid Lizards in Northern Taiwan by Species Distribution Model

• Main Authors: Shan-Ta Tao, 陶善達
• Other Authors: 林雨德
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/96303004999256740531

碩士 === 國立臺灣大學 === 生態學與演化生物學研究所 === 101 === Character displacement hypothesis states: when species with character similarity coexist in the same community, the population in sympatric location would displace in one or more characters. The increased differences in character space would reduce the strength of inter-specific competition for limited resources. Both Japalura swinhonis and Japalura polygonata xanthostoma occur in northern Taiwan. The two congeners have similar morphology and ecology, yet different macro-habitats. I applied species distribution model to identify environmental features that describe their differences in macrohabitat use, and predict the potential contact zone of the two species. Then use the latter to examine the pattern of character displacement. The results of species distribution modeling showed the distance to human-use area and total area of forest contribute the most to the distribution of the two species. The models allowed me to successfully locate four main regions of species coexistence. I found evidence for character displacement in most sympatric locations of Japalura swinhonis and Japalura polygonata xanthostoma. In four of the sympatric locations I surveyed, three of them showed significant intra-specific differences in their morphology between sympatric and allopatric locations. The head related parameters were consistently smaller for both species. While inter-specific difference of bite force related characters were greater in the sympatric than allopatric locations, characters related to sprint speed were more similar in the sympatric locations. Character displacement may be effect by inter-specific competition and predation risk in sympatric location, therefore, the characters related to sprint speed would be more similar.