The study defines ‘species richness’ as the number of species found in one place and suggests that the temperate regions generally became species poor around the Pleistocene Period (1.8 million – 10,000 years ago) because of changing climatic conditions. The ecosystems found on the Qionglai and Changbai Mountains in China are survivors from this time and can provide an understanding of how certain conditions preserve such a richness of species during major climate changes.
Changbaishan Mountain, in North-East China, is a volcano with a crater lake and is covered with a variety of distinct communities shaped by altitude, orientation, topography and water flow. Vegetation ranges from Alpine meadow and scrub at the top of the mountain, to mixed hardwood forests near the base. Although exposed to volcanic eruptions and the effects of past glaciation periods, there are more types of animals and plants found there than in any other area of similar climate and it contains greater species richness than some countries in Europe. The Qionglai Mountain ranges in the South-West of China contain even more botanical types with over 4000 species of flowering plants. Combined with the adjacent Hengduan Mountains, the area covers the richest temperate site in the world.
Reasons for the high levels of species richness in these mountains include:
- a large, well connected area, adjacent to forests on three sides allowing access for many species
- a wide variation in altitude providing numerous specialist niches and the opportunity for species to move
vertically to adapt to changing conditions
- a diverse range of local habitats formed by the complex shape of the area, including peaks, hollows, lakes,
valleys as well as gorges which provide shelter for species in harsher conditions
- a diversity of underlying landforms allowing a broad range of habitats
- a good summer rainfall ensures the area does not dry out
- a long north-south axis of the area includes a variety of climate states from warm temperate to cold temperate
- geological activity such as volcanic processes encourage a diverse ecology by providing new habitats for species
Identifying areas in other parts of the world which contain similar characteristics could help guide current conservation efforts. Such habitats ought to receive special protection in order to help preserve a broad array of biodiversity.