Are the living collections of the world's botanical gardens following species-richness patterns observed in natural ecosystems?

摘要

Botanical gardens aim to promote the awareness, study and conservation of plant species diversity, but little is known about the species diversity of botanical gardens themselves. We therefore investigated whether the species richness of the world's botanical gardens is related to their size, age and geographical location by compiling data from gardens in 124 different countries. The data show that even in these highly managed ecosystems, species richness can be described in terms of a relatively small number of large-scale patterns. As with most natural ecosystems, there were positive species-area and species-age relationships. There was also a positive latitudinal gradient in species richness, which contrasts with the trend observed in natural ecosystems. This discrepancy may be due to the use of heated greenhouses at high latitudes, the rarity of old botanical gardens in the tropics, and the problem of poverty in developing countries, where most hotspots of plant biodiversity are located. There is thus a need to allocate more funds to botanical gardens in species-rich regions. This study also calls for an increase in the coordination of data management between botanical gardens. © Birkhäuser Verlag, 2007.