7 research outputs found
Crisis of Japanese Vascular Flora Shown By Quantifying Extinction Risks for 1618 Taxa
<div><p>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 km<sup>2</sup>. 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.</p></div
Relationships between number of protected cells and number of species remaining as threatened (probability of extinction in the next 100 years ≥10%).
<p>Cells are selected to maximize the reduction of extinction risk (see text for details).</p
Number of extinct species predicted by the population viability analyses (PVAs) of 1618 vascular plant taxa in Japan.
<p>Results correspond to different scenarios in the choice of a rate of change class for the PVAs: classes were drawn (i) only from a pool of observed classes for each taxon in all of Japan (pool <i>P</i> = 1.0); (ii) from both the pool and the classes observed in the same cell at a certain ratio (<i>P</i> = 0.2–0.8); and (iii) only from those observed in the same cell (<i>P</i> = 0.0). Results from assumption (i) always gave the greatest rate of extinction.</p
Contribution of pressure types causing decline of local populations in (a) whole of Japan, (b) national protected areas (cells with >20% of protected areas) and (c) core zones of national protected area (cells with >20% of core zones).
<p>For each combination of pressure type and species, the number of cells with declining population was calculated, and the numbers are summed for each pressure type.</p
List of vascular plant species categorized as Extinct (EX) or Extinct in the Wild (EW) in the Red List compiled by Ministry of the Environment of Japan in 2012.
<p>List of vascular plant species categorized as Extinct (EX) or Extinct in the Wild (EW) in the Red List compiled by Ministry of the Environment of Japan in 2012.</p