XVI International Botanical Congess
We analyzed the 1997 IUCN Red List of Threatened Plants for taxonomic patterns in endangerment. Monocots, dicots, and pteridophytes were treated separately, and patterns of taxonomic selectivity within each group were analyzed. In each of these groups, log-likelihood tests revealed that the distribution of threatened taxa is significantly different from the pattern predicted by a model in which threat risk is distributed at random across families, yet family size did not notably contribute to this effect. An expansion of the binomial distribution enabled us to attribute the pattern to specific families showing higher than expected proportions of threatened taxa. These analyses provide a first step toward an integrated understanding of phylogenetic and ecological factors associated with endangerment, and an initial framework for proactive conservation of plant lineages.