ABSTRACT
This chapter discusses the six types of ecosystems in Japan. They are: forest ecosystems; farmland ecosystems; urban ecosystems; inland water ecosystems; coastal and marine ecosystems; and island ecosystems. Genetic diversity of Japanese species has been rarely reviewed and summarized, though Takafumi Ohsawa and Y. Ide compiled and reviewed various case studies on genetic diversity of Japanese plant species, suggesting the genetic hotspots where many regionally unique species occurred. The outline of ecosystems and species diversity in Japan is described in National Biodiversity Strategy of Japan 2012–2020. The remnant ecosystems retaining genuine natural environments are important to know natural characteristics of Japan, and are regarded as core areas for biodiversity conservation. Japan has a number of islands that are scattered across 3,000 km from north to south, being surrounded by four marine areas, such as the Sea of Okhotsk, the Japan Sea, the East China Sea, and the Pacific Ocean.
