Gap analysis for in situ conservation of crop genepools: implications of the Convention on Biological Diversity: G. B. Ingram & J. T. Williams, Biodiversity Letters, 1(5), 1993, pp 141–148

Abstract

The numbers of mature specimens of all extant cycad taxa in the wild, in public gardens and in private collections were estimated from a census carried out during 1991 and 1992. The data for the wild plants and those in public gardens appear to be comprehensive and reasonably accurate for most cycad genera except Cycas and Zamia. A low frequency of responses from private collectors has resulted in a significant underestimate of the number of specimens in private ownership. Abundance in the wild is extremely variable but, with some important exceptions, positively correlated with numbers in cultivation, where large numbers of plants are held by a relatively small number of owners. Revisions of the previously listed conservation status for each taxon are suggested on the basis of wild number estimates in view of the lack of detailed population studies. Well-maintained and correctly accessioned cycad collections are important ex situ genetic resources of educational, research and conservation value; several botanic gardens are presently involved in cycad conservation projects. A major revision of the earlier threatened species assignments is proposed, in which taxa are placed into extinct, critical, endangered, vulnerable and safe/low-risk categories on the basis of the wild number estimates obtained in the census. These assignments are based on species numbers in view of the lack of data at the population level.