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Effects of acorn abundance on density dependence in a Japanese wood mouse ( Apodemus speciosus ) population
Author(s) -
Saitoh Takashi,
Vik Jon Olav,
Stenseth Nils Chr.,
Takanishi Toshikazu,
Hayakashi Shintaro,
Ishida Nobuo,
Ohmori Masaaki,
Morita Toshio,
Uemura Shigeru,
Kadomatsu Masahiko,
Osawa Jun,
Maekawa Koji
Publication year - 2008
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/s10144-008-0076-6
Subject(s) - acorn , abundance (ecology) , density dependence , biology , wood mouse , population density , apodemus , population , intraspecific competition , ecology , demography , sociology
We analysed the effects of Quercus crispula acorn abundance on the density dependence of the large Japanese wood mouse Apodemus speciosus using time series data (1992–2007). The data were obtained in a forest in northern Hokkaido, Japan, by live‐trapping rodents and directly counting acorns on the ground. Acorn abundance in one year clearly influenced the abundance of wood mice in the following year in all models examined based on the Gompertz and Ricker model; in addition, the abundance of wood mice had effects on the population. Acorn abundance influenced the strength of density dependence (intraspecific competition) of the wood mouse population. When the abundance of acorns was high, density dependence was relaxed, and as a result the equilibrium density at which the population growth rate decreased to zero became higher. Those effects of acorn abundance were regarded as a nonlinear perturbation effect (sensu Royama 1992). The nonlinearity of density dependence was also detected; higher densities had stronger effects on population growth rates.