Aljos Farjon

Measuring the fate of plant diversity: towards a foundation for future monitoring and opportunities for urgent action

Vascular plants are often considered to be among the better known large groups of organisms, but gaps in the available baseline data are extensive, and recent estimates of total known (described) seed plant species range from 200 000 to 422 000. Of these, global assessments of conservation status using International Union for the Conservation of Nature (IUCN) categories and criteria are available for only approximately 10 000 species. In response to recommendations from the Conference of the Parties to the Convention on Biological Diversity to develop biodiversity indicators based on changes in the status of threatened species, and trends in the abundance and distribution of selected species, we examine how existing data, in combination with limited new data collection, can be used to maximum effect. We argue that future work should produce Red List Indices based on a representative subset of plant species so that the limited resources currently available are directed towards redressing taxonomic and geographical biases apparent in existing datasets. Sampling the data held in the worlds major herbaria, in combination with Geographical Information Systems techniques, can produce preliminary conservation assessments and help to direct selective survey work using existing field networks to verify distributions and gather population data. Such data can also be used to backcast threats and potential distributions through time. We outline an approach that could result in: (i) preliminary assessments of the conservation status of tens of thousands of species not previously assessed, (ii) significant enhancements in the coverage and representation of plant species on the IUCN Red List, and (iii) repeat and/or retrospective assessments for a significant proportion of these. This would result in more robust Sampled Red List Indices that can be defended as more representative of plant diversity as a whole; and eventually, comprehensive assessments at species level for one or more major families of angiosperms. The combined results would allow scientifically defensible generalizations about the current status of plant diversity by 2010 as well as tentative comments on trends. Together with other efforts already underway, this approach would establish a firmer basis for ongoing monitoring of the status of plant diversity beyond 2010 and a basis for comparison with the trend data available for vertebrates.

Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants.

Plants provide fundamental support systems for life on Earth and are the basis for all terrestrial ecosystems; a decline in plant diversity will be detrimental to all other groups of organisms including humans. Decline in plant diversity has been hard to quantify, due to the huge numbers of known and yet to be discovered species and the lack of an adequate baseline assessment of extinction risk against which to track changes. The biodiversity of many remote parts of the world remains poorly known, and the rate of new assessments of extinction risk for individual plant species approximates the rate at which new plant species are described. Thus the question ‘How threatened are plants?’ is still very difficult to answer accurately. While completing assessments for each species of plant remains a distant prospect, by assessing a randomly selected sample of species the Sampled Red List Index for Plants gives, for the first time, an accurate view of how threatened plants are across the world. It represents the first key phase of ongoing efforts to monitor the status of the world’s plants. More than 20% of plant species assessed are threatened with extinction, and the habitat with the most threatened species is overwhelmingly tropical rain forest, where the greatest threat to plants is anthropogenic habitat conversion, for arable and livestock agriculture, and harvesting of natural resources. Gymnosperms (e.g. conifers and cycads) are the most threatened group, while a third of plant species included in this study have yet to receive an assessment or are so poorly known that we cannot yet ascertain whether they are threatened or not. This study provides a baseline assessment from which trends in the status of plant biodiversity can be measured and periodically reassessed.

Cone and ovule development in Cunninghamia and Taiwania (Cupressaceae sensu lato) and its significance for conifer evolution

We examined the early developmental stages of the seed cones and seeds of two conifer genera, Cunninghamia and Taiwania, using scanning electron microscope (SEM) images of freshly collected material. In recent similar studies, these two taxa were not described. The present paper aims to fill that gap. Both genera appear to have features crucial to the understanding of the evolution of the cupressaceous cone, characteristic of the families Cupressaceae and Taxodiaceae, and provide further evidence for the need to merge these families. These features are: the ovuliferous scale in Cunninghamia develops as a small lobe with each of three ovules; in Taiwania these lobes are absent, but a small ridge could be a vestige of them. In neither of these two genera does an ovuliferous scale develop to maturity and only limited intercalary growth transforms the bracts, of which only their width and final shape distinguishes them from sterile leaves. Thus, the bracts, not the ovuliferous scales, form the mature cone in these two genera. This trend is continued in more derived genera of Cupressaceae. Another key extant taxon that has helped to elucidate the evolution of this type of conifer cone is Sciadopitys; similar studies have already been done on this genus, and we compared our findings to them. We also considered certain fossil Mesozoic conifer cones, which shed further light on the evolution of the cupressaceous cone. The evidence from these various genera strongly indicates that recently reconstructed phylogenies of gymnosperms based on molecular evidence from extant taxa do not reflect the evolution that actually happened. Such studies need to take into account nonmolecular evidence, as detailed here.

Conifer conservation in Vietnam: three potential flagship species

Discoveries of new species and new records of species are the order of the day in Vietnam, a country with a high level of biodiversity and many areas still largely unexplored. In recent years many conifers have been discovered for the first time in the country, and this paper focuses on three of these. The Vulnerable Pinus krempfii is an endemic of exceptional scientific interest. The globally Vulnerable Taiwania cryptomerioides, a conifer of ancient lineage in the Cupressaceae previously only known to occur with certainty in Taiwan and the border region between Myanmar and China, is a new discovery for Vietnam, where it is Critically Endangered. The Critically Endangered Xanthocyparis vietnamensis, a new genus and species in the Cupressaceae, was described in 2001 and is restricted to limestone outcrops on the border with China. All three species are of high conservation concern due to their rarity and because of threats to their survival from expanding cultivation, felling and fires. We discuss the suitability of these three conifers as flagship species to promote forest conserva- tion in Vietnam. We also discuss the problems involved in the protection of these species, and the efforts that are currently being undertaken to conserve them.

The Kew Review: Conifers of the World

SummaryWhen a natural group of plants has over many years been comprehensively and intensively studied, a large body of data, analysis and evaluation has accumulated. It is in the nature of such work on the taxonomy of such a group that this information is to be found scattered in various publications, such as research papers, checklists, monographs, Floras and other compilations. As time and research progress, some of this information will become outdated and superseded by new publications, but other information remains current and valuable. To give a review of this can provide us not only with a guide to this resource, but also with an introduction to the group in question. It may stimulate new research, as inevitably we will find that all has not been said and done, even about a group so well studied as the conifers. I hope that this paper will meet these aims.

Three More Masterpieces by Aljos Farjon on Conifers: Two Updates and One New

The Maritime and Ligurian Alps represent a regional hotspot of plant biodiversity found in the Mediterranean. Historical factors, complex geomorphology and habitat diversity may have played key roles to mould the biogeographical singularity of this area. This study represents the first regional phylogeographic attempt to better assess the complex evolutionary history of an endemic plant (Gentiana ligustica), which is found throughout this hotspot, across a large altitudinal and ecological gradient. Here, we examine how historical and topographical factors have affected the geographic structure of sequence variation at internal transcribed spacers (ITS) of ribosomal DNA. Sequence data revealed a fine-scale geographical structure of molecular variation, and the presence of contact areas between groups of populations differentiated by ITS ribotypes. A comparison between the sequence distribution and topography suggests that the genetic structure of G ligustica is the result of isolation and drift. Combined phylogeographic, Pleistocene glaciation, topographic and geologic data suggest the presence of several genetically differentiated refugia, at the margins of the ice sheets in the southern part of the Maritime and Ligurian Alps during the last two glaciations (Riss and Wurm), as well as in some valleys and cliffs during the Wurm.

Plate 442. Pinus pungens

The distribution, history, taxonomy, ecology, uses and cultivation of Pinus pungens Lamb. (Pinaceae), a native of the eastern United States of America, are discussed, and a full description and illustration are provided.

Plate 371. Cryptomeria japonica

The history, distribution, taxonomy, habitat and cultivation requirements of Cryptomeria japonica (Thunb. ex L.f.) D. Don (Cupressaceae), which is considered endemic to Japan, are discussed; a full description with illustrations of the species is provided.