TITLE:
Morphological Study of Glochidion obovatum under Heavy Browsing Pressure by Sika Deer
AUTHORS:
Shogo Takei, Kazuhiro Yoshioka, Satoru Yamada, Hiroshi Hayakawa, Jun Yokoyama, Katsura Ito, Shinichi Tebayashi, Ryo Arakawa, Tatsuya Fukuda
KEYWORDS:
Deer; Defence; Frequency; Herbivore; Island; Sika
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.9,
April
16,
2014
ABSTRACT: To clarify the modification of physical defences of Glochidion obovatum Sieb. et Zucc., we compared the length of
spine-like branches and frequency of lateral branches of G. obovatum between Kashima Island, which supports a high density
of sika deer (Cervus nippon), and its
neighbouring areas. The length of spine-like branches of G. obovatum in
Kashima Island was not significantly longer than that of the neighbouring areas,
but the frequency of lateral branches on the island was higher than that of the
neighbouring areas. Since the branches of G. obovatum are heavily foraged by the sika deer, the shrub form of
the species has evolved into the bonsai form, suggesting increased frequency of
occurrence of lateral branches, which could develop as shoot-like branches.
Thus, the observed features are facultative defence mechanisms of G. obovatum against heavy browsing in a
small-sized island with very high density of sika deer.