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Cycad classification: concepts and recommendations.

Book cover for Cycad classification: concepts and recommendations.

Description

This book presents the current state of our knowledge of the systematics of the approximately 300 species of cycads. It has been developed from 15 papers presented at the conference in Miami. Guidelines are presented for the designation of species, species boundaries and species groupings, thus clarifying what has been a confused area of research. Two appendices are included in this volume. The fi...

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Chapter 2 (Page no: 13)

Saving ghosts? The implications of taxonomic uncertainty and shifting infrageneric concepts in the cycadales for red listing and conservation planning.

A comparison of the cycad Red Lists from 1978 to 2002 shows that taxonomy has had a profound influence on the outcomes of the Red List process. The descriptions of new species, as well as taxonomic revisions, have increased the number of recognized cycad taxa from 136 in 1978, to over 300 at the time of publication. During this time, the proportion of threatened taxa has fluctuated from a low of 46% of all cycad taxa in 1978, to a high of 82% in 1997, and is currently estimated to be 52%. At least one-third of the changes in the Red List are due to taxonomic changes, which reflects an increase in taxonomic activity between 1978 and 2002. In addition to new species, there were 48 changes in the Red List between 1978 and 2002 as a result of uncertainty about the infrageneric status of cycad taxa. Frequent changes in threatened status are not helpful for conservation planning and could even undermine the Red List process. The IUCN has introduced robust criteria for Red Listing to deal with inadequate population data and ecological uncertainty. The results of this analysis show that cycad taxonomists need to develop consistent and widely accepted concepts for infrageneric taxa to reduce the influence of taxonomic uncertainty on the Red Listing process.

Other chapters from this book

Chapter: 1 (Page no: 1) 'We Hold these Truths ...'. Author(s): Walters, T. Osborne, R. Decker, D.
Chapter: 3 (Page no: 23) Character evolution, species recognition and classification concepts in the Cycadaceae. Author(s): Hill, K. D.
Chapter: 4 (Page no: 45) Morphological characters useful in determining species boundaries in Cycas (Cycadaceae). Author(s): Lindström, A.
Chapter: 5 (Page no: 57) Comments on Cycas, Dyerocycas and Epicycas (Cycadaceae). Author(s): Chen ChiaJui Hill, K. D. Stevenson, D. W.
Chapter: 6 (Page no: 69) Classification concepts in Encephalartos (Zamiaceae). Author(s): Vorster, P.
Chapter: 7 (Page no: 85) Classification concepts in Macrozamia (Zamiaceae) from Eastern Australia. Author(s): Forster, P. I.
Chapter: 8 (Page no: 95) Classification concepts in Ceratozamia (Zamiaceae). Author(s): Whitelock, L. M.
Chapter: 9 (Page no: 109) Relationships and phytogeography in Ceratozamia (Zamiaceae). Author(s): Vovides, A. P. Pérez-Farrera, M. A. González, D. Avendaño, S.
Chapter: 10 (Page no: 127) A morphometric analysis of the Ceratozamia norstogii complex (Zamiaceae). Author(s): Pérez-Farrera, M. A. Vovides, A. P. Hernández-Sandoval, L. González, D. Martínez, M.
Chapter: 11 (Page no: 137) Hypotheses on the relationship between biogeography and speciation in Dioon (Zamiaceae). Author(s): Gregory, T. J. Chemnick, J.
Chapter: 12 (Page no: 149) Molecular phylogeny of Zamia (Zamiaceae). Author(s): Caputo, P. Cozzolino, S. Luca, P. de Moretti, A. Stevenson, D. W.
Chapter: 13 (Page no: 159) Systematics of Meso-American Zamia (Zamiaceae). Author(s): Schutzman, B.
Chapter: 14 (Page no: 173) Zamiaceae of Bolivia, Ecuador and Peru. Author(s): Stevenson, D. W.
Chapter: 15 (Page no: 195) In search of the true tree: guidelines for classification. Author(s): Osborne, R. Walters, T.

Chapter details

  • Author Affiliation
  • Kirstenbosch Research Centre, National Botanical Institute, Private Bag X7, Claremont 7735, South Africa.
  • Year of Publication
  • 2004
  • ISBN
  • 9780851997414
  • Record Number
  • 20043021921