Hortus Botanicus Leiden

Leiden, Netherlands

Hortus Botanicus Leiden

Leiden, Netherlands
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Havinga R.,Hortus Botanicus Amsterdam | Kool A.,University of Oslo | Achille F.,Museum National d'Histoire Naturelle | Bavcon J.,University of Ljubljana | And 17 more authors.
Taxon | Year: 2016

Botanic gardens have been exchanging seeds through seed catalogues for centuries. In many gardens, these catalogues remain an important source of plant material. Living collections have become more relevant for genetic analysis and derived research, since genomics of non-model organisms heavily rely on living material. The range of species that is made available annually on all seed lists combined, provides an unsurpassed source of instantly accessible plant material for research collections. Still, the Index Seminum has received criticism in the past few decades. The current exchange model dictates that associated data is manually entered into each database. The amount of time involved and the human errors occurring in this process are difficult to justify when the data was initially produced as a report from another database. The authors propose that an online marketplace for seed exchange should be established, with enhanced search possibilities and downloadable accession data in a standardised format. Such online service should preferably be supervised and coordinated by Botanic Gardens Conservation International (BGCI). This manuscript is the outcome of a workshop on July 9th, 2015, at the European botanic gardens congress “Eurogard VII” in Paris, where the first two authors invited members of the botanic garden community to discuss how the anachronistic Index Seminum can be transformed into an improved and modern tool for seed exchange. © International Association for Plant Taxonomy (IAPT) 2016.

Couvreur T.L.P.,IRD Montpellier | Maas P.J.M.,Wageningen University | Meinke S.,Hortus botanicus Leiden | Meinke S.,Leiden University | And 3 more authors.
Botanical Journal of the Linnean Society | Year: 2012

Identification keys are provided for all genera currently recognized in Annonaceae. Separate keys are presented for the Neotropics (34 genera), Africa-Madagascar (40 genera) and Asia-Australasia (42 genera). These keys are based on a combination of vegetative and fertile characters. © 2012 The Linnean Society of London.

Hoang V.S.,Hanoi University | Baas P.,National Herbarium of the Netherlands | Kessler P.J.A.,Hortus Botanicus Leiden | Slik J.W.F.,CAS Xishuangbanna Tropical Botanical Garden | And 2 more authors.
Journal of Tropical Forest Science | Year: 2011

In order to understand the influence of human disturbance and the physical environment on plant biodiversity in Ben En National Park, Vietnam, we analysed species composition and density in forest plots with diverse soils and varying degrees of human disturbance. Soil factors significantly influenced tree species composition, although they only explained 5.7% of the observed data variance. Human factors (disturbance) were second most important in explaining species composition and density, accounting for 4.4% of variance. Changes in species composition related to human disturbance varied mostly independently of soils. The species composition of slightly and heavily disturbed forest differed significantly, with species of low conservation value being most common in heavily disturbed forest, while endangered species and important timber trees were most common in least disturbed forest. Density of treelets was higher in limestone forest than in non-limestone forest. Timber trees and other useful plant species used for a whole range of non-timber forest products (NTFPs) were more abundant in the less disturbed plots, which were located far away from villages and roads. Basal area in less disturbed forest was also larger than in heavily disturbed forest, indicating that the pressures of illegal logging and harvesting were closely connected to travel distances to nearest villages. Limiting the accessibility to forest resources should therefore be a priority in forest conservation as a first step to safeguard the rich biodiversity and stocks of useful plants in the park. © Forest Research Institute Malaysia.

Vollering J.,Naturalis Biodiversity Center | Schuiteman A.,Herbarium | de Vogel E.,Naturalis Biodiversity Center | van Vugt R.,Hortus botanicus Leiden | Raes N.,Naturalis Biodiversity Center
Journal of Biogeography | Year: 2016

Aim: The aims of this study were (1) to assess the spatial distribution of orchid species richness in New Guinea, and (2) to examine patterns of species turnover in the orchid community through phytogeographical regionalization. We aimed to achieve these goals using botanical collection records, species distribution models (SDMs) and partitioning around medoids (PAM) clustering. Location: New Guinea, the Bismarck Archipelago and surrounding islands. Methods: We combined 6760 collection records of 532 orchid species with 16 uncorrelated environmental predictor variables, to model species distributions at 5 arc-min resolution, using the presence-only modelling algorithm, Maxent. All SDMs were tested for significant deviation from random expectation using bias-corrected null models. The results from significant SDMs were stacked to create a map of orchid species richness. The same significant SDMs were used to derive phytogeographical regions through a PAM cluster analysis. Results: Of the 532 modelled species distributions, 283 showed significantly stronger correlation with environmental conditions than expected by chance alone. It is inferred that the central mountain ranges of eastern New Guinea, including part of the Papuan Peninsula, harbour the highest levels of orchid species richness. The study area was divided into eight phytogeographical regions that maximized internal community similarity among orchids. Two of these regions are found almost exclusively in western New Guinea, while the remainder are more evenly distributed. Main conclusions: Our study provides an objective assessment of the distribution of relative orchid species richness in New Guinea. The eight derived phytogeographical regions are largely consistent with existing knowledge of the island's internal biogeography. These findings give insight into one of the global hotspots of orchid diversity, and improve our understanding of the phytogeography of New Guinea. © 2016 John Wiley & Sons Ltd.

van der Ent A.,University of Queensland | van Vugt R.,Hortus Botanicus Leiden | Wellinga S.,Beukenlaan 14
Biodiversity and Conservation | Year: 2015

Rothschild’s slipper orchid (Paphiopedilum rothschildianum), originating from Kinabalu Park in the Malaysian state of Sabah, on Borneo Island, is one of the most famous orchid species in the world. It caused a sensation when it was first discovered in the nineteenth century, and the precise details of its habitat were long kept a (trade) secret. The species is now widely available as a result of artificial propagation in culture, but the ecology of this species in the wild remained largely unknown. An expedition was organised by the authors to collect detailed habitat information, and to perform chemical analysis on P. rothschildianum leaves and associated rhizosphere soils. The species occurs on serpentinite (ultramafic) landslides at 500–1800 m asl on slightly acidic (means ranging from pH 5.8–6.7) soils with a cation exchange complex dominated by magnesium. The nutrient status (rhizosphere soil concentrations of phosphorus and potassium) is low, both the plant-available fraction and the total concentrations. The extreme soil chemistry was also reflected in the P. rothschildianum leaf chemistry with low concentrations of these elements and low foliar nitrogen, potassium and phosphorus. Reciprocal transplantation of P. rothschildianum on non-ultramafic soils has proven successful, which shows that soil chemistry is not limiting its growth, at least in culture. Rather, P. rothschildianum is restricted to open vegetation with a lack of competition brought about by a very unusual combination of factors: recurring landslides setting back vegetation succession, and extreme soil chemistry limiting plant establishment. Finally, the IUCN Red List status of P. rothschildianum and other Paphiopedilum-species of Kinabalu Park was provisionally assessed. © 2015, Springer Science+Business Media Dordrecht.

Chaowasku T.,Leiden University | Kessler P.J.A.,Hortus Botanicus Leiden
Nordic Journal of Botany | Year: 2013

Seven new species of the genus Miliusa are described from Thailand (M. fragrans, M. hirsuta, M. intermedia, M. nakhonsiana, M. sessilis, M. thailandica, and M. umpangensis). A key to the 19 species of Miliusa in Thailand is provided. In addition, the complete taxonomic nomenclature of all known species of Miliusa in Thailand is given, with several new proposed synonyms. The new as well as the known species of Miliusa in Thailand are classified into four morphological groups on the basis of a combination of flower and/or inflorescence position and inner petal morphology proposed earlier. © 2013 The Authors.

Appelhans M.S.,Hortus Botanicus Leiden | Appelhans M.S.,Leiden University | Kessler P.J.,Hortus Botanicus Leiden | Kessler P.J.,Leiden University | And 5 more authors.
Journal of Biogeography | Year: 2012

Aim The family Rutaceae (rue family) is the largest within the eudicot order Sapindales and is distributed mainly in the tropical and subtropical regions of both the New World and the Old World, with a few genera in temperate zones. The main objective of this study is to present molecular dating and biogeographical analyses of the subfamily Spathelioideae, the earliest branching clade (which includes eight extant genera), to interpret the temporal and spatial origins of this group, ascertaining possible vicariant patterns and dispersal routes and inferring diversification rates through time. Location Pantropics. Methods A dataset comprising a complete taxon sampling at generic level (83.3% at species level) of Spathelioideae was used for a Bayesian molecular dating analysis (beast). Four fossil calibration points and an age constraint for Sapindales were applied. An ancestral area reconstruction analysis utilizing the dispersal-extinction-cladogenesis model and diversification rate analyses was conducted. Results Dating analyses indicate that Rutaceae and Spathelioideae are probably of Late Cretaceous origin, after which Spathelioideae split into a Neotropical and a Palaeotropical lineage. The Palaeotropical taxa have their origin inferred in Africa, with postulated dispersal events to the Mediterranean, the Canary Islands, Madagascar and Southeast Asia. The lineages within Spathelioideae evolved at a relatively constant diversification rate. However, abrupt changes in diversification rates are inferred from the beginning of the Miocene and during the Pliocene/Pleistocene. Main conclusions The geographical origin of Spathelioideae probably lies in Africa. The existence of a Neotropical lineage may be the result of a dispersal event at a time in the Late Cretaceous when South America and Africa were still quite close to each other (assuming that our age estimates are close to the actual ages), or by Gondwanan vicariance (assuming that our age estimates provide minimal ages only). Separation of land masses caused by sea level changes during the Pliocene and Pleistocene may have been triggers for speciation in the Caribbean genus Spathelia. © 2012 Blackwell Publishing Ltd.

Chaowasku T.,Leiden University | Kessler P.J.A.,Hortus botanicus Leiden
Nordic Journal of Botany | Year: 2014

The genus Miliusa in Cambodia and Vietnam is reviewed. Cambodia and Vietnam each harbors six species of Miliusa, including three which are described as new to science: one from Cambodia (Miliusa cambodgensis sp. nov.), the other two from Vietnam (M. astiana and M. ninhbinhensis spp. nov.). In addition, a complete nomenclature and relevant information about the Miliusa species previously known from Cambodia and Vietnam are provided, including keys to the Cambodian and Vietnamese species, the designation of a lectotype for M. baillonii and the synonymization of M. balansae var. elongatoides, M. chunii and M. sinensis with M. balansae. © 2014 The Authors.

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