190 research outputs found
Taxonomic surrogacy in biodiversity assessments, and the meaning of Linnaean ranks
Copyright © 2006 The Natural History MuseumThe majority of biodiversity assessments use species as the base unit. Recently, a series of studies have suggested replacing numbers of species with higher ranked taxa (genera, families, etc.); a method known as taxonomic surrogacy that has an important potential to save time and resources in assesments of biological diversity. We examine the relationships between taxa and ranks, and suggest that species/higher taxon exchanges are founded on misconceptions about the properties of Linnaean classification. Rank allocations in current classifications constitute a heterogeneous mixture of various historical and contemporary views. Even if all taxa were monophyletic, those referred to the same rank would simply denote separate clades without further equivalence. We conclude that they are no more comparable than any other, non-nested taxa, such as, for example, the genus Rattus and the phylum Arthropoda, and that taxonomic surrogacy lacks justification. These problems are also illustrated with data of polychaetous annelid worms from a broad-scale study of benthic biodiversity and species distributions in the Irish Sea. A recent consensus phylogeny for polychaetes is used to provide three different family-level classifications of polychaetes. We use families as a surrogate for species, and present ShannonâWiener diversity indices for the different sites and the three different classifications, showing how the diversity measures rely on subjective rank allocations.Y. Bertrand, F. Pleijel and G. W. Rous
Recovering plant data for Guinea-Bissau: implications for biodiversity knowledge of West Africa
ReviewThe rich plant diversity that characterizes the West African Region and the inherent
knowledge of their flora and vegetation has been the backbone of scientific explorations during the
past centuries. The evolution of botanical knowledge on Guinea-Bissau, throughout the 16th and
20th centuries is reviewed. We present and discuss floristic data collected by scientific expeditions
between the mid-1700s to 1974, when the Portuguese colonial period ended. Expeditions undertaken
by French naturalists provided some of the earliest plant collections. A list of herbarium specimens
collected by the French naturalist Jardin, in the BijagĂłs Islands in ca. 1847â1858 is presented here
for the first time, while in the late 1800s some Portuguese naturalists also explored Guinea-Bissau.
During the colonial period (1915â1974), Gomes e Sousa published the first comprehensive study of
the territoryâs flora while EspĂrito Santo assembled the largest plant collection. Our review applies
a multi-disciplinary perspective to fill important lacuna regarding biodiversity knowledge of this
under-researchedWest African country. It constitutes the first study tracing the long term evolution
of knowledge on Guinea Bissau's plant diversity, which provides the basis for understanding trends
and research priorities, in particular in conservation and botanical fieldsinfo:eu-repo/semantics/publishedVersio
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