The Bark Stripping Behavior and its Correlation with Population Status and Parasite Infection in Formosan Sambar Deer (Rusa unicolor swinhoii)

• Main Authors: Hew Shun Win, 邱峋文
• Other Authors: Weng, Guo-Jing
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/12357131820801857771

碩士 === 國立屏東科技大學 === 野生動物保育研究所 === 103 === Bark stripping behavior by cervids commonly occurs throughout the world. Current hypotheses to explain this behavior include: (1) barks provide energy, nutrition, water, or other chemicals; (2) barks enhance digestion; (3) human disturbance induces the behavior; (4) the behavior is restricted to certain individuals; and (5) debarking is a self-medication behavior. Previous studies showed various debarking pattern in different areas, leading to different interpretations for its cause. Formosan sambar deer (Rusa unicolor swinhoii) are widespread along the Central Mountain Range of Taiwan. The population has grown steadily in recent years. Different extent of debarking occurred in their distribution range. Understanding the reason for bark stripping is necessary for future management. This study aimed to investigate the debarking pattern and its correlation with the environmental or biological factors, hoping to reveal why sambar deer debark. Six sampling sites were selected from Yushan, Taroko and Shei-pa National Park. This study measured the proportion of trees debarked, tree species preferred for debarking, population density, sex ratio, occurrence index, composition of tree species. The status of gastrointestinal parasite infection is investigated by fecal analyses and further converted to debarking pressure index. The results show that although sambar deer debark many tree species, only few tree species are preferred, and the preferred tree species varies with sampling site. Furthermore, proportions of debarked trees were not correlated with either population density(r=0.12, p=0.81) or occurrence index(r=0.56, p=0.24) and clearly differed between northern and southern sampling sites, probably due to specific need for barks by certain populations, genetic differentiation among populations, or variation in the chemical composition of barks in different areas. Our results also show that proportion of debarked tree was significantly correlated with debarking pressure index(r=0.88, p=0.02; Spearman Rho=0.98, p=0.0003), indicating that Formosan sambar likely debarks to mitigate the infection of gastrointestinal parasites.