Taxonomy and conservation ecology of the genus Pinguicula L. (Lentibulariaceae)

This thesis, “Taxonomy and conservation ecology of the genus Pinguicula L. (Lentibulariaceae)”, consists of 4 chapters. An abstract for each chapter is as follows: Chapter 1: Red List assessments of the genus Pinguicula L. The genus Pinguicula L. (Lentibulariaceae), comprising of 91 taxa all of which are carnivorous, is repeatedly collected from the field and is grown by amateur collectors. The current status of many Pinguicula taxa in the wild is mostly unavailable due to little information although a number of taxa are endemic to a small area and those are thought to be threatened. The International Union for Conservation (IUCN) Red List Categories and Criteria is a standard for evaluating the risk of extinction. In this chapter, all the 91 taxa recognised were evaluated using the criteria, Extent of occurrence (EOO) and Area of Occupancy (AOO), based on herbarium specimens. The results suggest that at least 61 % of taxa are evaluated as threatened, and the risk is higher in “Mexico and Central America”than “Europe and Western Asia”, both of which are Pinguicula biodiversity hotspots. Urgent action for the conservation of the taxa and their habitats will be necessary.Chapter 2: Phylogenetic analyses of the genus Pinguicula L. The current taxonomy of the genus Pinguicula is based on the flower morphology, and it is divided into three subgenera, Isoloba, Pinguicula, and Temnoceras. Some recent molecular analyses, however, suggest that the results do not agree with the current subgeneric classification based on the morphological characters. In this chapter, three DNA regions, matK and trnK, rpl32-trnL in chloroplast DNA (cpDNA), and the internal transcribed spacer (ITS) in nuclear ribosomal DNA (nrDNA) from 81 Pinguicula taxa, were sequenced. The three results are inconsistent with the taxonomy based on floral morphology. The molecular results, particularly ITS, infer that most of Pinguicula taxa are monophyletic within each geographic area. Chromosome and basic numbers are also agreed well with their distributions. Concerning the same seasonal growth cycle, forming winter rosettes or hibernacula, it is not just simply ecologically convergent but the taxa within the same region are phylogenetically closely related to one another. Phylogenetic trees inferred from the three regions and combined genes are also somewhat different from one another. Further research with other genes will be necessary to support the theory discussed in this chapter.Chapter 3: The effect of geographical and environmental factors on patterns of species richness in the genus Pinguicula L. A number of Pinguicula species are confined to a small geographical area and those are often endemic to the area while only a few species are distributed widely. This chapter explored what geographical and environmental factors affect species richness of Pinguicula. Four geographical factors, land area (km2), latitude of country centroid, mean elevation, mean distance to nearest coastline (km), and six Koeppen-Geiger climate categories, A (tropical-type climate category), B (dry-type climate category), C (temperate-type climate category), D (cold-type climate category), E (polar-type climate), and H (alpine-type climate) for each country were used for the analyses to determine whether the number of taxa in all countries, Europe and Western Asia, Northeastern Asia, and America were correlated with those factors. Overall, relatively weak positive correlations were found between the number of taxa and those factors. Remarkable results in this study have suggested that species richness is significantly correlated with land area, i.e. large countries have more species, probably due to diversity of climates. Furthermore the number of taxa is significantly correlated with climate B (dry) in all countries and America. The result implies that an impact of species richness in Mexico correlated with B (dry). Species richness of Pinguicula is particularly seen insmall wet places surrounded by large dry areas. More detailed studies on local ecology will be necessary to consider the distribution of the genus. Chapter 4: A revision of the genus Pinguicula L. The most recent revision of the genus Pinguicula was attempted by Casper in 1966, but the number of species expanded from 46 to almost double with some new sectional delimitations. Taxonomic confusion is, however, often seen and therefore a revision with recent knowledge is necessary. In this study, a review of literature and over 6,800 herbarium specimens from 167 herbaria was performed, and as a result, 91 Pinguicula taxa (89 species and 2 varieties) have been recognised. Based on the phylogenetic analysis in Chapter 2, a new sectional delimitation of the genus is proposed. In this study, the 91 taxa were divided into 11 sections including newly proposed sections, Alpinae, Andinae, Caribensis, Elongatae, Membraniformis, Mesoamericana, and Pumiliformis, as well as existing sections, Cardiophyllum, Isoloba, Nana, and Pinguicula. Keys to section and species, a brief description, distribution maps, and line drawings for each taxon are provided. Due to limited availability of materials on this occasion, some Italian taxa newly described in the recent years were unable to be examined in this study.