Role of Endemism and Other Factors in Determining the Introduction Success of Rare and Threatened Species in Tashkent Botanical Garden

Abstract

Although rare and threatened species are maintained in many botanical gardens around the world, detailed reports on the success or failure of their introduction appear infrequently, which makes it difficult to understand the major constraints of growing imperilled species in botanical garden living collections. Though intuitively, a level of endemism appears to be important, its role as a predictor of species cultivation success in the garden living collections has never been tested. This paper summarizes the experience of the Tashkent Botanical Garden in creating and maintaining living collections of rare and threatened species of Uzbekistan, trying to understand the role of endemism and other factors in the success and failure of these species cultivation. We found that out of 100 rare and threatened species introduced, the cultivation of 26 failed. Most of these species were endemic to the country, occupying soil types and habitats different from those of the garden site. However, surprisingly, the introduction of many analogous species has been successful. This implies that some narrow endemics can be successfully grown in botanical gardens, but to predict which can and which cannot is impossible, and there are no alternatives to introduction trials. Overall, the large number of rare and threatened species for which introductions were successful confirms the important role of ex situ conservation in preserving critically endangered biodiversity and should stimulate further work in this direction. The future efforts of the garden staff will focus on two major objectives: (i) collecting seeds of endangered species that have so far skipped attention or their collection missions have not been successful; and (ii) propagating those species that have proven cultivation success and using the propagated material for in situ actions.