Naturalized alien flora of the world: species diversity, taxonomic and phylogenetic patterns, geographic distribution and global hotspots of plant invasion

Using the recently built Global Naturalized Alien Flora (GloNAF) database, containing data on the distribution of naturalized alien plants in 483 mainland and 361 island regions of the world, we describe patterns in diversity and geographic distribution of naturalized and invasive plant species, taxonomic, phylogenetic and life-history structure of the global naturalized flora as well as levels of naturalization and their determinants. The mainland regions with the highest numbers of naturalized aliens are some Australian states (with New South Wales being the richest on this continent) and several North American regions (of which California with 1753 naturalized plant species represents the world's richest region in terms of naturalized alien vascular plants). England, Japan, New Zealand and the Hawaiian archipelago harbour most naturalized plants among islands or island groups. These regions also form the main hotspots of the regional levels of naturalization, measured as the percentage of naturalized aliens in the total flora of the region. Such hotspots of relative naturalized species richness appear on both the western and eastern coasts of North America, in north-western Europe, South Africa, south-eastern Australia, New Zealand, and India. High levels of island invasions by naturalized plants are concentrated in the Pacific, but also occur on individual islands across all oceans. The numbers of naturalized species are closely correlated with those of native species, with a stronger correlation and steeper increase for islands than mainland regions, indicating a greater vulnerability of islands to invasion by species that become successfully naturalized. South Africa, India, California, Cuba, Florida, Queensland and Japan have the highest numbers of invasive species. Regions in temperate and tropical zonobiomes harbour in total 9036 and 6774 naturalized species, respectively, followed by 3280 species naturalized in the Mediterranean zonobiome, 3057 in the subtropical zonobiome and 321 in the Arctic. The New World is richer in naturalized alien plants, with 9905 species compared to 7923 recorded in the Old World. While isolation is the key factor driving the level of naturalization on islands, zonobiomes differing in climatic regimes, and socioeconomy represented by per capita GDP, are central for mainland regions. The 11 most widely distributed species each occur in regions covering about one third of the globe or more in terms of the number of regions where they are naturalized and at least 35% of the Earth's land surface in terms of those regions' areas, with the most widely distributed species Sonchus oleraceus occuring in 48% of the regions that cover 42% of the world area. Other widely distributed species are Ricinus communis, Oxalis corniculata, Portulaca oleracea, Eleusine indica, Chenopodium album, Capsella bursa-pastoris, Stellaria media, Bidens pilosa, Datura stramonium and Echinochloa crus-galli. Using the occurrence as invasive rather than only naturalized yields a different ranking, with Lantana camara (120 regions out of 349 for which data on invasive status are known), Calotropis procera (118), Eichhornia crassipes (113), Sonchus oleraceus (108) and Leucaena leucocephala (103) on top. As to the life-history spectra, islands harbour more naturalized woody species (34.4%) than mainland regions (29.5%), and fewer annual herbs (18.7% compared to 22.3%). Ranking families by their absolute numbers of naturalized species reveals that Compositae (1343 species), Poaceae (1267) and Leguminosae (1189) contribute most to the global naturalized alien flora. Some families are disproportionally represented by naturalized aliens on islands (Arecaceae, Araceae, Acanthaceae, Amaryllidaceae, Asparagaceae, Convolvulaceae, Rubiaceae, Malvaceae), and much fewer so on mainland (e.g. Brassicaceae, Caryophyllaceae, Boraginaceae). Relating the numbers of naturalized species in a family to its total global richness shows that some of the large species-rich families are over-represented among naturalized aliens (e.g. Poaceae, Leguminosae, Rosaceae, Amaranthaceae, Pinaceae), some under-represented (e.g. Euphorbiaceae, Rubiaceae), whereas the one richest in naturalized species, Compositae, reaches a value expected from its global species richness. Significant phylogenetic signal indicates that families with an increased potential of their species to naturalize are not distributed randomly on the evolutionary tree. Solanum (112 species), Euphorbia (108) and Carex (106) are the genera richest in terms of naturalized species; over-represented on islands are Cotoneaster, Juncus, Eucalyptus, Salix, Hypericum, Geranium and Persicaria, while those relatively richer in naturalized species on the mainland are Atriplex, Opuntia, Oenothera, Artemisia, Vicia, Galium and Rosa. The data presented in this paper also point to where information is lacking and set priorities for future data collection. The GloNAF database has potential for designing concerted action to fill such data gaps, and provide a basis for allocating resources most efficiently towards better understanding and management of plant invasions worldwide

Moleculaire evolutie in de systematiek

Al in de tijd van Aristoteles streefden mensen naar een indeling van de levende natuur. Aanvankelijk waren deze classificaties volledig intuïtief en subjectief, maar met de komst van de evolutietheorie ontstond het besef dat een classificatie van het leven de evolutionaire historie zou moeten weerspiegelen. Fylogenetische systematiek is het vakgebied in de biologie dat streeft naar het ontdekken van evolutionaire verwantschappen tussen soorten en hogere taxa. Naast morfologische kenmerken kunnen ook moleculaire kenmerken gebruikt worden om evolutionaire historie te ontsluieren. George Nuttall was in het begin van de 20e eeuw de eerste die moleculaire data gebruikte om de verwantschappen tussen soorten te bepalen. Hij gebruikte de reactie tussen antilichamen en antigenen van verschillende organismen om tot uitspraken over verwantschappen van verschillende groepen dieren te komen. Zo kwam hij bijvoorbeeld tot de conclusie dat mensen meer verwant zijn met apen uit de Oude Wereld dan met Nieuwe Wereld apen. Nuttall was zijn tijd echter ver vooruit. Het duurde nog ongeveer 50 jaar totdat James Watson en Francis Crick met de ontdekking van de moleculaire structuur van DNA ervoor zorgden dat moleculaire data op een veel bredere schaal gebruikt konden worden. In 1955 publiceerde Fred Sanger de eerste vergelijking van aminozuursequenties. Hij gebruikte de verschillen tussen insuline-eiwitten van runderen, varkens en schapen om aan te tonen dat deze verschillen gebruikt kunnen worden om evolutionaire verwantschappen tussen deze taxa te bepalen

Spoorzoeken in de Orchideeën: naamsveranderingen als consequenties van modern systematisch onderzoek

Recent studies on evolutionary relationships between the species of Orchis s.l. and Dactylorhiza (Orchidaceae) using molecular techniques reveal that the systematic classification of these groups needs revising. The new classification involves changes in the circumscription of, for example, Aceras, Anacamptis, Coeloglossum, Dactylorhiza, and Orchis. The importance of the use of multiple independent lines of evidence in the evaluation of phylogenetic relationships is emphasised. For floras, the consequences of adopting classifications that are not (exclusively) based on morphological characters are discussed

A conservation genetic study of Rafflesia speciosa (Rafflesiaceae): patterns of genetic diversity and differentiation within and between islands

Rafflesia speciosa is a threatened endo-holoparasitic species. It has several populations in the Central Panay Mountain Range (CPMR) of Panay island and a single population on Negros Island. Because R. speciosa is the only Philippine species of the genus that is not endemic to an individual island, it is a suitable species for improving our understanding of the factors underlying the high island endemism of Philippine Rafflesia. For this purpose and to inform the conservation management of R. speciosa, patterns of genetic diversity and differentiation were studied using 15 microsatellite loci and samples from nine populations. None of these populations shows evidence of inbreeding and R. speciosa has similar levels of heterozygosity as generally observed in outcrossing or perennial plant species. The results of AMOVA and Bayesian cluster analyses indicate that the Negros population is genetically differentiated from the CPMR populations. In addition, it has lower genetic diversity than similar-sized R. speciosa populations. These findings suggest that sea straits potentially provide significant reproductive barriers to Rafflesia species, and are perhaps responsible for their high island endemism. The general lack of genetic differentiation among the CPMR populations as suggested by the AMOVA, PCoA, and STRUCTURE results indicates recent gene flow among them and this finding improves our understanding of the geographical scale and context at which gene flow between Rafflesia populations occurs. Conservation efforts should be targeted towards avoiding further habitat degradation in the Negros population. We also recommend protective status for the entire CPMR and reforestation efforts to mitigate the severe habitat fragmentation, destruction, and degradation in this area

Revision of Coelogyne section Fuliginosae (Orchidaceae)

Section Fuliginosae Pfitzer & Kraenzl. of the genus Coelogyne Lindl. is revised. With the help of a pollen study, principal component and cluster analyses with morphological characters and a survey of some additional data, two species are recognized (C. fimbriata and C. triplicatula), including one dubious variety (C. fimbriata var. acuminata). Eleven names are reduced to synonymy. Three species formerly included in sect. Fuliginosae by several authors are excluded ( (C. micrantha, C. treutleri and C. schilleriana)

Taxonomy, ecology, and conservation status of Philippine Rafflesia (Rafflesiaceae)

The number of Rafflesia species (Rafflesiaceae) reported for the Philippines has grown explosively from two before 2002 to ten or eleven presently. We present an overview of the current knowledge of Philippine Rafflesia by providing a comprehensive account of all the recognized species with their taxonomy, distribution and ecology, plus a key and photographs to aid in identification. Their conservation status and that of the rain forest habitats they require is discussed

Senecio pokohinuensis (Asteraceae), a new combination for an endemic species of Mokohinau Islands, Hauraki Gulf (Tikapa Moana o Hauraki), northern Te Ika a Maui / North Island, Aotearoa / New Zealand

Previous research has demonstrated that Senecio repangae subsp. repangae and subsp. pokohinuensis have independent evolutionary origins. Here, we therefore elevate subsp. pokohinuensis to species rank: Senecio pokohinuensis. Updated morphological descriptions for both species are also provided

New combinations and names for some Philippine vascular plants

New names and new combinations are presented for 29 Philippine species in the families Acanthaceae, Aspleniaceae, Cucurbitaceae, Gesneriaceae, Lauraceae, Myrtaceae, Oleaceae, Thelypteridaceae, Urticaceae, and Vitaceae. Seventeen names are lectotypified