臺灣中部山區地景因子對台灣高山田鼠(Microtus kikuchii)和台灣森鼠(Apodemus semotus)族群遺傳結構之影響

Abstract

Landscape features, including vegetation type, elevation, and topography, can influence the dispersal and distribution of animals, and lead to variation in spatial population genetic structure. According to the isolation-by-distance (IBD) model, the genetic distances among populations can be positively correlated with geographic distances. Recently, researchers have started to use the least-cost-path distance instead of Euclidean distance in examining IBD because of the unrealistic meaning of the latter to organisms. In this thesis, I studied the influences of landscape features on population genetic structure of two rodent species, the Taiwan field vole (Microtus kikuchii) and the Formosan field mouse (Apodemus semotus Thomas) in central Taiwan. Through amplifying the D-loop sequence in mtDNA from animal tissues from 6~8 populations of each species, I computed the genetic distance among populations, the FST value. I calculated the geographic distances under three models: Euclidean distance and two least-cost-path distances based on topography or vegetation type, using geographic information system (GIS). I then analyzed the correlation between genetic distance and the geographic distances conducted from the three models. The results showed that there was no population genetic structure among Apodemus semotus, yet a strong genetic structure was present among Microtus kikuchii populations, and significantly positively correlated with vegetation type.