INTECOL (International Ecological Congress) at Montreal on August 10, 2005

Contributed Oral Session 96: Restoration and Adaptive Management: Fresh and Salt Water Wetlands; Deer

Adaptive management for sika deer in Hokkaido Island, Japan since 1998

H. Matsuda^1,*, Uno, H.², K. Kaji², T. Saitoh³, K. Tamada² and T. Kurumada².
¹ Yokohama National University, Yokohama, Kanagawa, Japan, ² Hokkaido Institute of Environmental Sciences, Sapporo, Hokkaido, Japan, ³ Hokkaido University, Sapporo, Hokkaido, Japan.

Abstract- We made and executed the adaptive management program for sika deer in Hokkaido Island, Japan. The goal and aim of the management program are to control the deer population between two threshold of relative abundance, to decrease damage of agriculture and forestry and to utilize deer as a traditional resource. Hokkaido Prefectural Government started the management program since 1998. We applied adaptive management to the program. The harvesting pressure varies with the relative population size in the previous hunting season (feedback control). The interim estimate of the absolute population size is reexamined by successive monioring of spotlight census (adaptive learning). Since the management plan was introduced, the population size began to decrease, despite the fact that the rate of population decline is substantially slower than we expected. We devised a new method to estimate game populations using relative population sizes and numbers harvested in a population management program for sika deer (Cervus nippon) in eastern Hokkaido, Japan. The Government of Hokkaido estimated the absolute deer population to be between 74,000 and 166,000 individuals (90% CI) as of March 1994. We took the ratio of the population index obtained by a spotlight census in year t to that in 1993. We estimated the relative population size in 2000 to be between 58 and 101% (95% CI). We analyzed a stage-structured population dynamics model that included uncertainty and yearly changes in parameter values. We assumed that ranges of biological parameter values were consistent with the 16-21% rate of natural population increase per year estimated by a field survey. The population dynamics model suggested that if the population size in 1993 was below 170,000, males would have become extinct. The model also suggested that if its size in 1993 was larger than 330,000, the population would not have subsequently decreased. Therefore, we estimated the population in 1993 to be between these two extremes.

[A47] Matsuda H, Uno H, Kaji K, Tamada K, Saitoh T, Hirakawa H (2002) Harvest-based estimation of population size for Sika deer on Hokkaido Island, Japan. Wildlife Society Bulletin 30(4):1160-1171.
[A38] Matsuda H., Kaji, K., Uno, H., Hirakawa, H., Saitoh, T. (1999) A management policy for sika deer based on sex-specific hunting. Researches on Population Ecology41:139-149.
[C8] Matsuda H et al (Committee on Ecosystem Management of The Ecological Society of Japan) (2005) Guideline for nature restoration projects. Japanese Journal of Conservation Ecology 10: 63-75 (in Japanese with English abstract).