title: Crisis of Japanese vascular flora shown by quantifying extinction risks for 1618 taxa.
abstract: Although many people have expressed alarm that we are witnessing a mass extinction, few projections have been quantified, owing to limited availability of time-series data on threatened organisms, especially plants. To quantify the risk of extinction, we need to monitor changes in population size over time for as many species as possible. Here, we present the world's first quantitative projection of plant species loss at a national level, with stochastic simulations based on the results of population censuses of 1618 threatened plant taxa in 3574 map cells of ca. 100 km2. More than 500 lay botanists helped monitor those taxa in 1994-1995 and in 2003-2004. We projected that between 370 and 561 vascular plant taxa will go extinct in Japan during the next century if past trends of population decline continue. This extinction rate is approximately two to three times the global rate. Using time-series data, we show that existing national protected areas (PAs) covering ca. 7% of Japan will not adequately prevent population declines: even core PAs can protect at best <60% of local populations from decline. Thus, the Aichi Biodiversity Target to expand PAs to 17% of land (and inland water) areas, as committed to by many national governments, is not enough: only 29.2% of currently threatened species will become non-threatened under the assumption that probability of protection success by PAs is 0.5, which our assessment shows is realistic. In countries where volunteers can be organized to monitor threatened taxa, censuses using our method should be able to quantify how fast we are losing species and to assess how effective current conservation measures such as PAs are in preventing species extinction.
authors.affiliation: Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Kadoya
authors.affiliation: Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Takenaka
authors.affiliation: Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, Japan.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Ishihama
authors.affiliation: Nature Conservation Society of Japan, Shinkawa, Chuo-ku, Tokyo, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Fujita
authors.affiliation: Tokushima Prefectural Museum, Bunka-no-mori Park, Hachiman-cho, Tokushima-shi, Tokushima, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ogawa
authors.affiliation: Kanagawa Prefectural Museum of Natural History, Odawara, Kanagawa, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Katsuyama
authors.affiliation: Faculty of Science, Kobe University, Kobe, Japan.
authors.forename: Yasuro
authors.initials: Y
authors.lastname: Kadono
authors.affiliation: Faculty of Applied Biological Sciences, Gifu University, Yanagido, Gifu, Japan.
authors.forename: Nobumitsu
authors.initials: N
authors.lastname: Kawakubo
authors.affiliation: Department of Biology, Aichi Kyoiku University, Igaya-cho, Kariya, Aichi, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Serizawa
authors.affiliation: Hokkaido University Museum, Sapporo, Hokkaido, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Environmental Science, Kumamoto University, Kumamoto, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takamiya
authors.affiliation: Division of Human Environment, University of Human Environments, Okazaki, Aichi, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Fujii
authors.affiliation: Faculty of Natural Environment and Information Sciences, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama city, Kanagawa, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Matsuda
authors.affiliation: Faculty of Natural Environment and Information Sciences, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama city, Kanagawa, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Muneda
authors.affiliation: Faculty of Science, University of the Ryukyus, Senbaru, Nishihara, Nakagami, Okinawa, Japan.
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Yokota
authors.affiliation: Center for Academic Resources and Archives, Botanical Gardens, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yonekura
authors.affiliation: Department of Biology, Kyushu University, Higashi-ku, Fukuoka, Japan.
authors.forename: Tetsukazu
authors.initials: T
authors.lastname: Yahara
mesh_terms: D053476:Extinction, Biological; D007564:Japan; D010802:Phylogeny; D058974:Phylogeography; D010944:Plants / Q000145:classification* / Q000235:genetics