The origin of cultivated mangosteen (Garcinia mangostana L. var. mangostana): Critical assessments and an evolutionary-ecological perspective

Mangosteen (Garcinia mangostana var. mangostana) is a popular tropical fruit, yet many aspects of its biology and evolutionary history are little known. Its origin remains contentious, although recent findings suggest G. mangostana L. var. malaccensis (Hook. f.) Nazre (synonym: G. malaccensis Hook. f.) as the sole progenitor. We review hypotheses on the origin of mangosteen and clarify points that have been affected by errors of fact and interpretation. The narrow focus and lack of detail in published results make their interpretation difficult. When possible, we support our interpretations with field observations and examination of herbarium specimens. We outline the main biological traits (e.g., dioecy, facultative apomixis, and polyploidy) of mangosteen and its wild relatives to infer traits that might have evolved during domestication of mangosteen. We find no clear indication that apomixis and polyploidy evolved during domestication. Polyploidy is known in the wild relatives, but apomixis has not yet been demonstrated. Also, we propose a testable new evolutionary-ecological framework that we call “Forest-Dusun Interface” to infer processes in the origin of mangosteen. Dusun (Malay) refers to subsistence orchards in this context. Lastly, we propose future studies to address identified knowledge gaps

Soil nitrogen concentration mediates the relationship between leguminous trees and neighbor diversity in tropical forests

Legumes provide an essential service to ecosystems by capturing nitrogen from the atmosphere and delivering it to the soil, where it may then be available to other plants. However, this facilitation by legumes has not been widely studied in global tropical forests. Demographic data from 11 large forest plots (16–60 ha) ranging from 5.25° S to 29.25° N latitude show that within forests, leguminous trees have a larger effect on neighbor diversity than non-legumes. Where soil nitrogen is high, most legume species have higher neighbor diversity than non-legumes. Where soil nitrogen is low, most legumes have lower neighbor diversity than non-legumes. No facilitation effect on neighbor basal area was observed in either high or low soil N conditions. The legume–soil nitrogen positive feedback that promotes tree diversity has both theoretical implications for understanding species coexistence in diverse forests, and practical implications for the utilization of legumes in forest restoration

The Asia‐Pacific Biodiversity Observation Network : 10‐year achievements and new strategies to 2030.

The Asia-Pacific Biodiversity Observation Network (APBON) was launched in 2009, in response to the establishment of the Biodiversity Observation Network under the Group on Earth Observations in 2008. APBON's mission is to increase exchange of knowledge and know-how between institutions and researchers concerning biodiversity science research in the Asia-Pacific (AP) region and thereby contribute to evidence-based decision-making and policy-making. Here we summarize APBON activities and achievements in its first 10 years. We review how APBON has developed networks, facilitated communication for sharing knowledge, and built capacity of researchers and stakeholders through workshops and publications as well as discuss the network plan. Key findings by APBON members include descriptions of species new to science, mapping tropical forest cover change, evaluating impacts of hydropower dams and climate change on fish species diversity in the Mekong, and mapping “Ecologically and Biologically Significant Areas” in the oceans. APBON has also contributed to data collection, sharing, analysis, and synthesis for regional and global biodiversity assessment. A highlight was contributing to the “Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services” regional report. New strategic plans target the development of national-level BONs and interdisciplinary research to address the data and knowledge gaps and increase data accessibility for users and for meeting societal demands. Strengthening networks in AP region and capacity building through APBON meetings will continue. By promoting monitoring and scientific research and facilitating the dialogue with scientists and policymakers, APBON will contribute to the implementation of conservation and sustainable use of biodiversity in the entire AP region.publishedVersio

The interspecific growth–mortality trade-off is not a general framework for tropical forest community structure

Resource allocation within trees is a zero-sum game. Unavoidable trade-offs dictate that allocation to growth-promoting functions curtails other functions, generating a gradient of investment in growth versus survival along which tree species align, known as the interspecific growth–mortality trade-off. This paradigm is widely accepted but not well established. Using demographic data for 1,111 tree species across ten tropical forests, we tested the generality of the growth–mortality trade-off and evaluated its underlying drivers using two species-specific parameters describing resource allocation strategies: tolerance of resource limitation and responsiveness of allocation to resource access. Globally, a canonical growth–mortality trade-off emerged, but the trade-off was strongly observed only in less disturbance-prone forests, which contained diverse resource allocation strategies. Only half of disturbance-prone forests, which lacked tolerant species, exhibited the trade-off. Supported by a theoretical model, our findings raise questions about whether the growth–mortality trade-off is a universally applicable organizing framework for understanding tropical forest community structure

Latitudinal patterns in stabilizing density dependence of forest communities

Numerous studies have shown reduced performance in plants that are surrounded by neighbours of the same species1,2, a phenomenon known as conspecific negative density dependence (CNDD)3. A long-held ecological hypothesis posits that CNDD is more pronounced in tropical than in temperate forests4,5, which increases community stabilization, species coexistence and the diversity of local tree species6,7. Previous analyses supporting such a latitudinal gradient in CNDD8,9 have suffered from methodological limitations related to the use of static data10,11,12. Here we present a comprehensive assessment of latitudinal CNDD patterns using dynamic mortality data to estimate species-site-specific CNDD across 23 sites. Averaged across species, we found that stabilizing CNDD was present at all except one site, but that average stabilizing CNDD was not stronger toward the tropics. However, in tropical tree communities, rare and intermediate abundant species experienced stronger stabilizing CNDD than did common species. This pattern was absent in temperate forests, which suggests that CNDD influences species abundances more strongly in tropical forests than it does in temperate ones13. We also found that interspecific variation in CNDD, which might attenuate its stabilizing effect on species diversity14,15, was high but not significantly different across latitudes. Although the consequences of these patterns for latitudinal diversity gradients are difficult to evaluate, we speculate that a more effective regulation of population abundances could translate into greater stabilization of tropical tree communities and thus contribute to the high local diversity of tropical forests

Pantropical variability in tree crown allometry

Aim Tree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about large‐scale variation and determinants in tropical tree crown allometry. In this study, we explored the continental variation in scaling exponents of site‐specific crown allometry and assessed their relationships with environmental and stand‐level variables in the tropics. Location Global tropics. Time period Early 21st century. Major taxa studied Woody plants. Methods Using a dataset of 87,737 trees distributed among 245 forest and savanna sites across the tropics, we fitted site‐specific allometric relationships between crown dimensions (crown depth, diameter and volume) and stem diameter using power‐law models. Stand‐level and environmental drivers of crown allometric relationships were assessed at pantropical and continental scales. Results The scaling exponents of allometric relationships between stem diameter and crown dimensions were higher in savannas than in forests. We identified that continental crown models were better than pantropical crown models and that continental differences in crown allometric relationships were driven by both stand‐level (wood density) and environmental (precipitation, cation exchange capacity and soil texture) variables for both tropical biomes. For a given diameter, forest trees from Asia and savanna trees from Australia had smaller crown dimensions than trees in Africa and America, with crown volumes for some Asian forest trees being smaller than those of trees in African forests. Main conclusions Our results provide new insight into geographical variability, with large continental differences in tropical tree crown allometry that were driven by stand‐level and environmental variables. They have implications for the assessment of ecosystem function and for the monitoring of woody biomass by remote sensing techniques in the global tropics

Nomenclatural updates and new records in Peninsular Malaysian Pentaphylacaceae

Volume: 68Start Page: 215End Page: 22

A taxonomic revision of loxocarpus (gesneriaceae) / Yao Tze Leong

Henckelia sect. Loxocarpus is a small taxon consisting of c. 26 taxa distributed in West Malesia. The present study is the first comprehensive taxonomic revision for all species of Loxocarpus. This study has four objectives. The first one is to provide a review of macro-morphological diversity and variation within Loxocarpus. Second, to carry out phylogenetic analyses to determine whether Loxocarpus is distinct from or is a section within Henckelia based on DNA sequences and morphological data. Third is to provide a full taxonomic revision of Loxocarpus. And last, to provide ecology and phytogeographic perspectives of Loxocarpus species and their conservation status. Molecular phylogenetic studies showed that Loxocarpus is distinct from Henckelia and nested within a few Asian and Malesian twisted-fruited genera clade. However, it is paraphyletic. This finding is in contrast with morphological data analysis result which showed the monophyly of Loxocarpus species. In the taxonomic revision, Loxocarpus is reinstated as a genus with a revised generic circumscription. Twenty three species are recognised in this taxonomic treatment, including 15 species formerly described as Loxocarpus species are reinstated, 5 new combinations are made, 6 species are synonymised with one recognised as a variety, 4 species are determined as novelties, and 6 incompletely known taxa are enumerated. A key to all species and regional keys are provided to aid species identification. Species descriptions with full synonymy, geographic distribution with distribution maps, habitat and ecology information are given. Identification lists for herbarium specimens is provided. iv Based on corolla morphology, Loxocarpus species were divided into two informal groups ‗A‘ and ‗B‘. This grouping to a certain extent correlates with phylogenetic analysis results and distribution pattern. Morphological characters were assessed in the light of their taxonomical value. Molecular phylogenetic analyses were based on a dataset of two markers, namely trnL-F intron spacer and Internal Transcribed Spacer (ITS). Twenty samples from Loxocarpus species were included as ingroup, 31 taxa were selected from ‗Asian and Malesian twisted group‘ as outgroup. Two analysis methods, namely Bayesian Inference and Maximum Parsimony, were implemented. Ecological aspects of Loxocarpus species are presented. Study showed that habit is correlated with habitat. Pollination and dispersal as inferred from morphology and observation are discussed. Most probably, Loxocarpus species are pollinated by Trigona bees and seeds are dispersed by rain-drop ballistic. The Riau Pocket was determined as the centre of highest species diversity. Seventeen out of 24 taxa are narrowly endemic (c. 71 %). Conservation status for all species was assessed and 5 out of 24 taxa (c. 21 %) fall within ‗threatened‘ categories. The three important research questions (Section 1.2) were answered in this study. First, it is distinct from Henckelia/Codonoboea and warrants generic status. Second, Loxocarpus is a paraphyletic taxon. Third, the characters circumscribing Loxocarpus are expanded so that the genus now includes species with longer (> 10 mm) capsules

Aristolochia vallisicola (Aristolochiaceae), a new species from Peninsular Malaysia

A new species in the genus Aristolochia (Aristolochiaceae), A. vallisicola T.L.Yao, from Peninsular Malaysia is described and illustrated. Among all Peninsular Malaysian Aristolochia, it is the only species with a pinnately veined lamina and a disc-liked perianth limb. A distribution map is provided and its conservation status is assessed as Least Concern