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Biodiversity occurences and patterns from the angle of systematics

Abstract : In the current context of biodiversity crisis, it is essential to understand where and how life is distributed. Using biodiversity data managed by the GBIF (>640 million occurrences) covering 24 taxonomic classes, I investigated one of the best-known biodiversity patterns: the latitudinal diversity gradient (LDG), which is characterized by an increase in specific richness as we approach the equator. This objective first led me to produce informatics tools for handling large amount of data (Big data paradigm), before evaluating the quality of primary biodiversity data. Two important outcomes resulted from this evaluation. First, I highlight that a strong taxonomic bias exists in biodiversity occurrences. This bias implies that some taxa are more studied than others, creating a knowledge gap detrimental to our understanding of biodiversity as a whole. This bias is strongly impacted by societal preferences rather than research activity. Second, a radical change in biodiversity data gathering practices is happening: primary biodiversity data are now mostly observation-based and not specimen-based. Assets and liabilities of this shift are discussed, while the role of voucher specimens is reiterated and, for observations, the need for ancillary data is underlined. Finally, six hypotheses proposed to explain the LDG are tested on a cleaned dataset encompassing eight taxonomic classes. A recent, but never tested, version of the geometric constraint hypothesis is refuted, while the productivity hypothesis is strongly supported.
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Submitted on : Monday, October 22, 2018 - 4:19:07 PM
Last modification on : Friday, January 7, 2022 - 3:52:53 AM
Long-term archiving on: : Wednesday, January 23, 2019 - 4:24:58 PM


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  • HAL Id : tel-01901059, version 1


Julien Troudet. Biodiversity occurences and patterns from the angle of systematics. Biodiversity. Université Pierre et Marie Curie - Paris VI, 2017. English. ⟨NNT : 2017PA066568⟩. ⟨tel-01901059⟩



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