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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. Source

Cruaud A.,French National Institute for Agricultural Research | Ronsted N.,Jodrell Laboratory | Ronsted N.,University of Minnesota | Ronsted N.,Entrance | And 29 more authors.
Systematic Biology | Year: 2012

It is thought that speciation in phytophagous insects is often due to colonization of novel host plants, because radiations of plant and insect lineages are typically asynchronous. Recent phylogenetic comparisons have supported this model of diversification for both insect herbivores and specialized pollinators. An exceptional case where contemporaneous plant-insect diversification might be expected is the obligate mutualism between fig trees (Ficus species, Moraceae) and their pollinating wasps (Agaonidae, Hymenoptera). The ubiquity and ecological significance of this mutualism in tropical and subtropical ecosystems has long intrigued biologists, but the systematic challenge posed by 750 interacting species pairs has hindered progress toward understanding its evolutionary history. In particular, taxon sampling and analytical tools have been insufficient for large-scale cophylogenetic analyses. Here, we sampled nearly 200 interacting pairs of fig and wasp species from across the globe. Two supermatrices were assembled: on an average, wasps had sequences from 77 of 6 genes (5.6 kb), figs had sequences from 60% of 5 genes (5.5 kb), and overall 850 new DNA sequences were generated for this study.We also developed a newanalytical tool, Jane 2, for event-based phylogenetic reconciliation analysis of very large data sets. Separate Bayesian phylogenetic analyses for figs and fig wasps under relaxed molecular clock assumptions indicate Cretaceous diversification of crown groups and contemporaneous divergence for nearly half of all fig and pollinator lineages. Event-based cophylogenetic analyses further support the codiversification hypothesis. Biogeographic analyses indicate that the present-day distribution of fig and pollinator lineages is consistent with a Eurasian origin and subsequent dispersal, ather than with Gondwanan vicariance. Overall, our findings indicate that the fig-pollinator mutualism represents an extreme case among plant-insect interactions of coordinated dispersal and long-term codiversification. [Biogeography; coevolution; cospeciation; host switching; long-branch attraction; phylogeny.] © 2012 The Author(s). Source

Kasuya T.,University of Tsukuba | Takehashi S.,Non profit organization | Hoshino T.,Japan National Institute of Advanced Industrial Science and Technology | Hoshino T.,Hokkaido University | Noordeloos M.E.,National Herbarium of the Netherlands
Sydowia | Year: 2010

An entolomatoid fungus, Entoloma aprile is newly recorded from Japan. Basidiome morphology of the species is described and illustrated based on the Japanese specimens. ITS sequences were obtained from Japanese E. aprile and three related species, viz. E. clypeatum f. clypeatum, E. clypeatum f. hybridum and E. sepium. Basidiomata of E. aprile were highly homologous (99.4 % - 100.0 %) among our collected specimens and were separated from other known Entoloma spp. in the dendrogram based on ITS sequences. This results supported our morphological observation that E. aprile differed from those of allied species. Mycorrhizae of E. aprile on Populus maximowiczii in the cool-temperate deciduous forests of Hokkaido, Japan were observed by stereo, light and scanning electron microscopy for the first time. In studied mycorrhizae, the root cap, meristem, and apical region of the cortex disappeared. Fungal hyphae of the mycorrhizae invaded root tissues. Hyphal sheath outside of the cortex was composed of plectenchymatous and pseudoparenchymatous hyphae divided into three layers according to hyphal thickness and arrangement. Those morphological characteristics suggest that mycorrhizae of E. aprile are of the same type as those of allied Entoloma species associated with rosaceous and ulmaceous plants. Source

Newbery D.M.,University of Bern | Lingenfelder M.,Albert Ludwigs University of Freiburg | Poltz K.F.,University of Bern | Ong R.C.,Japan Forestry and Forest Products Research Institute | Ridsdale C.E.,National Herbarium of the Netherlands
Forest Ecology and Management | Year: 2011

At Danum Valley, Sabah, dipterocarp forest is affected by moderately-strong droughts which perturb the ecosystem. Analysing stem growth for c. 3700 understorey trees (12.5-<50. cm girth), measured over four periods (between 1986 and 2007), response to an ENSO-related event (1998) was followed. Relative growth rates (rgr) of the 48 most abundant species in the size class were considered individually, and as relative changes between periods. From them a measure reactivity was derived. Whilst a third of species differed from one another in rgr, within-species rates were highly variable: often species had very different (pluralistic) response patterns over time. The rgr decreased in the drought period, increased and overcompensated directly afterwards, and later returned to original levels. The forest displayed moderate resistance, and high resilience and stability within c. 4. years of the perturbation. Oscillatory responses were more pronounced among true understorey species than among small trees of overstorey ones, suggesting that the former might play a key role in stabilization. Environmental stochasticity in the form of coloured noise may therefore be causing a major part of the variation in rain forest dynamics and explain its complexity. © 2011 Elsevier B.V. Source

Kumar E.S.S.,Jawaharlal Nehru Tropical Botanic Garden and Research Institute | Shareef S.M.,Jawaharlal Nehru Tropical Botanic Garden and Research Institute | Roy P.E.,Jawaharlal Nehru Tropical Botanic Garden and Research Institute | Veldkamp J.F.,National Herbarium of the Netherlands
Nordic Journal of Botany | Year: 2015

A new species of Clausena, C. agasthyamalayana is described and illustrated from the southern Western Ghats, Kerala, India. It is similar to C. indica but differs from it being of dwarf habit, and having greenish-black bark, smaller and fewer leaflets, obovate and coriaceous leaves with obtuse or emarginated apex, elliptic and obtuse petals, oblong-cordate anthers, consistently 4-locular ovary with 2 ovules in each chamber and ellipsoid fruits. © 2014 The Authors. Source

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