Response of Extremely Small Populations to Climate Change-A Case of Trachycarpus nanus in Yunnan, China.

Climate change affects the geographical distribution of plant species. Rare Trachycarpus nanus with a narrow distribution range, high medicinal value and extremely small population is facing increasing extinction risks under global climate change. In this study, 96 recorded occurrences and 23 environmental factors are used to predict the potential suitable area of T. nanus based on the optimized MaxEnt (3.4.4) model and ArcGIS (10.7) software. The results show that when the parameters are FC = LQ and RM = 1, the MaxEnt model is optimal and AUC = 0.946. The distribution patterns were predicted in the past, present, and four future phases, i.e., 2021-2040 (2030), 2041-2060 (2050), 2061-2080 (2070), and 2081-2100 (2090). The main factors are the annual precipitation (bio12), mean temperature of the coldest quarter (bio11), temperature seasonality (bio4), precipitation of the wettest quarter (bio16), and isothermality (bio3). The potential distribution of T. nanus is primarily concentrated in central Chuxiong, encompassing a total potential suitable area of 5.65 × 104 km2. In historical periods, the total habitat area is smaller than that in the present. In the future, the potential suitable area is generally increased. The centroid analysis shows that T. nanus will move to a high-altitude area and to the southeast. But its dispersal capacity may not keep up with the climate change rate. Therefore, additional protection sites for this species should be appropriately established and the habitat connectivity should be enhanced.

Forest characteristics, population structure and growth trends of threatened relict Pseudotsuga forrestii in China.

Pseudotsuga forrestii is a relict evergreen coniferous tree species in Pinaceae endemic to China. P. forrestii tree numbers have greatly decreased due to deforestation, over-utilization and habitat degradation. Here we clarify P. forrestii community types, structure, species diversity, seedling recruitments and growth trends. We identified four P. forrestii community types: (1) Pseudotsuga forrestii - Quercus guyavifolia - Acer davidii evergreen coniferous and broad-leaved mixed forest; (2) Pseudotsuga forrestii - Pinus yunnanensis - Quercus guyavifolia evergreen coniferous and broad-leaved mixed forest; (3) Pseudotsuga forrestii evergreen coniferous forest; (4) Pseudotsuga forrestii - Abies georgei var. smithii evergreen coniferous forest. P. forrestii forests are characterized by both warm temperate and temperate affinities. Simpson diversity, Pielou evenness, Shannon-Wiener diversity indices ranged from 0.75 to 0.76, 0.74-0.81, and 1.62-1.93, respectively, with no significant differences among the four forest types. The forest stratification was multilayered. The canopy layer was generally 10-25 m tall, with the emergent layer reached 25-42 m. DBH and age structures of P. forrestii showed multimodal distributions. Its maximum age P. forrestii was 570 years with a DBH of 143 cm. The growth of annual ring width of P. forrestii was slow, and generally decreased with age, whereas the basal area at the breast height increased with age. Established seedlings/saplings were mainly found in unstable micro-habitats. Regeneration of P. forrestii depends on moderate natural disturbances. Finally, we provide recommendations for P. forrestii conservation.

Ultrasound 3D reconstruction of malignant masses in robotic-assisted partial nephrectomy using the PAF rail system: a comparison study.

PURPOSE: In robotic-assisted partial nephrectomy (RAPN), the use of intraoperative ultrasound (IOUS) helps to localise and outline the tumours as well as the blood vessels within the kidney. The aim of this work is to evaluate the use of the pneumatically attachable flexible (PAF) rail system for US 3D reconstruction of malignant masses in RAPN. The PAF rail system is a novel device developed and previously presented by the authors to enable track-guided US scanning. METHODS: We present a comparison study between US 3D reconstruction of masses based on: the da Vinci Surgical System kinematics, single- and stereo-camera tracking of visual markers embedded on the probe. An US-realistic kidney phantom embedding a mass is used for testing. A new design for the US probe attachment to enhance the performance of the kinematic approach is presented. A feature extraction algorithm is proposed to detect the margins of the targeted mass in US images. RESULTS: To evaluate the performance of the investigated approaches the resulting 3D reconstructions have been compared to a CT scan of the phantom. The data collected indicates that single camera reconstruction outperformed the other approaches, reconstructing with a sub-millimetre accuracy the targeted mass. CONCLUSIONS: This work demonstrates that the PAF rail system provides a reliable platform to enable accurate US 3D reconstruction of masses in RAPN procedures. The proposed system has also the potential to be employed in other surgical procedures such as hepatectomy or laparoscopic liver resection.

Forest characteristics and population structure of Glyptostrobus pensilis, a globally endangered relict species of southeastern China.

The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. Forest community characteristics and population structure of G. pensilis in China have remained unknown up to now. We investigated six swamp forest stands and analyzed their forest community characteristics (i.e. vertical stratification, species composition, and diversity) and population structure, including the frequency distribution of DBH (diameter at breast height) and age-classes as found in Fujian Province, southeastern China. The vertical stratifications of all the forest stands were rather simple. The remaining wild specimens ranged from roughly 15 to some 357 years for an average of ca. 85 years, with only a few individuals less than 20 years old. Compared with the stands and populations of G. pensilis in Vietnam, the taxonomic compositions of the stands in the two regions were different, except for the dominant species-G. pensilis. The Shannon-Wiener index showed the overstory of each stand had much lower diversity (0.26 on average) in Fujian Province than that (1.97 on average) in Vietnam, whereas the diversity indices were about the same (around 2.41) for the understories in the two regions. Furthermore, we discovered 18 G. pensilis seedlings at the study sites in Fujian Province. This discovery demonstrates that G. pensilis regeneration is extremely poor and its populations are declining, although these populations are relatively healthier than those in Vietnam.

Author Correction: Identifying long-term stable refugia for relict plant species in East Asia.

In the original version of this Article, an incorrect sample size was provided for the number of relict species (443 instead of 442) and the number of relict forests (423 instead of 422). These errors have been corrected in both the PDF and HTML versions of the Article.

Identifying long-term stable refugia for relict plant species in East Asia.

Today East Asia harbors many "relict" plant species whose ranges were much larger during the Paleogene-Neogene and earlier. The ecological and climatic conditions suitable for these relict species have not been identified. Here, we map the abundance and distribution patterns of relict species, showing high abundance in the humid subtropical/warm-temperate forest regions. We further use Ecological Niche Modeling to show that these patterns align with maps of climate refugia, and we predict species' chances of persistence given the future climatic changes expected for East Asia. By 2070, potentially suitable areas with high richness of relict species will decrease, although the areas as a whole will probably expand. We identify areas in southwestern China and northern Vietnam as long-term climatically stable refugia likely to preserve ancient lineages, highlighting areas that could be prioritized for conservation of such species.

Heterogeneity of clonal patterns among patches of kudzu, Pueraria montana var. lobata, an invasive plant.

BACKGROUND AND AIMS: Viny species are among the most serious invasive plants, and better knowledge of how vines grow to dominate landscapes is needed. Patches may contain a single genotype (i.e. genet), a competitively dominant genet or many independent but interacting genets, yet the clonal structure of vining species is often not apparent. Molecular markers can discriminate among the genetic identities of entwined vines to reveal the number and spatial distribution of genets. This study investigated how genets are spatially distributed within and among discrete patches of the invasive vine kudzu, Pueraria montana var. lobata, in the United States. It was expected that ramets of genets would be spatially clustered within patches, and that an increase in the number of genets within a patch would be associated with a decrease in the average size of each genet. METHODS: Six discrete kudzu patches were sampled across 2 years, and 1257 samples were genotyped at 21 polymorphic allozyme loci. Variation in genotypic and genetic diversity among patches was quantified and patterns of genet interdigitation were analysed. KEY RESULTS: Substantial genotypic and genetic variation occurred within and among patches. As few as ten overlapping genets spanned up to 68 m(2) in one patch, while >90 % of samples were genetically unique in another patch. Genotypic diversity within patches increased as mean clone size decreased, although spatially widespread genets did not preclude interdigitation. Eight genets were shared across ≥2 patches, suggesting that vegetative dispersal can occur among patches. CONCLUSIONS: Genetically unique kudzu vines are highly interdigitated. Multiple vegetative propagules have become established in spatially discrete patches, probably through the movement of highway construction or maintenance machinery. The results suggest that common methods for controlling invasive vines (e.g. mowing) may inadvertently increase genotypic diversity. Thus, understanding vine architecture and growth has practical implications.

Porous Mg thin films for Mg-air batteries.

An alkaline primary Mg-air battery made from a porous Mg thin film displayed superior discharge performances, including a flat discharge plateau, a high open-circuit voltage of 1.41 V and a large discharge capacity of 821 mAh g(-1), suggesting that the electrochemical performances of Mg-air batteries can be improved by controlling the Mg anode morphology.

Novel phase change behavior of n-eicosane in nanoporous silica: emulsion template preparation and structure characterization using small angle X-ray scattering.

Silica microcapsules with hierarchical pore structure are prepared using a one step emulsion templated hydrolysis method. Silica particles of around 100 nm with percolated nanosized pores are self-assembled into micrometer scale spherical shells. The porous structure serves as an ideal host for shape stabilization of melted organic compounds. Small angle X-ray scattering (SAXS) results show that the n-eicosane encapsulated in nanoporous silica consists of mass fractal structure with a fractal dimension of 2.1. n-Eicosane encapsulated in the nanosized pores exhibits novel phase change behavior. A large melting point drop from 37.0 to 28.8 °C is observed, which is attributed to the strong interaction between the n-eicosane molecules and the silica skeleton.

Population persistence of a Tertiary relict tree Tetracentron sinense on the Ailao Mountains, Yunnan, China.

The persistence of the Tertiary relict tree Tetracentron sinense Oliv. on the eastern slope of the Ailao Mountains, Yunnan, SW China, was here studied in terms of population structure (size, age) and regeneration patterns. T. sinense occurred in unstable habitats by stream banks, on steep slopes, on scree slopes, or on roadsides near streams in narrow valleys, all places subject to frequent natural disturbances, whereas none were found on stable gentle slopes free of major disturbances at similar altitudes. Further, no established saplings of T. sinense were found in forests having high bamboo (Yushania crassicollis Yi) coverage in their understory. The size and age structure of T. sinense were multimodal. The reproduction of the tree was either by means of abundant minute wind-dispersed seeds or by resprouts in unstable habitats. These populations depended on disturbance or gap regeneration to survive. T. sinense, along with other tree life-forms including evergreen broad-leaved species and conifers, dominated in the forest canopy layer, even reaching the emergent layer in places. Results of the study provide insight into the ecological characteristics and survival mechanisms of this East Asian paleoendemic tree species. The study will provide a scientific basis for recommendations for the conservation of this species and for other Tertiary relict plants having similar regeneration dynamics.

Graphene oxide stabilized polyethylene glycol for heat storage.

Graphene oxide (GO) sheets were introduced to stabilize the melted polyethylene glycol (PEG) during the solid-liquid phase change process, which can be used as a smart heat storage system. The structural properties and phase change behaviors of the PEG-GO composites were comprehensively investigated as a function of the PEG content by means of various characterization techniques. The highest stabilized PEG content is 90 wt% in the composites, resulting in a heat storage capacity of 156.9 J g(-1), 93.9% of the phase change enthalpy of pure PEG. Notably, GO has much stronger impact on lowering of the phase change temperature of PEG compared with some other porous carbon materials (activated carbon and ordered mesoporous carbon) due to the unique thin layer structure of GO. Because of the high heat storage capacity and the moderate phase change temperature, the PEG-GO composite is a promising heat energy storage candidate at mild temperature.

Superior (de)hydrogenation properties of Mg-Ti-Pd trilayer films at room temperature.

In this paper, a series of Mg-Ti-Pd trilayer films with various thicknesses of the Ti interlayer were prepared by magnetron sputtering. The trilayer films could be reversibly (de)hydrogenated at room temperature. The relationship between structure and properties of Mg-Ti-Pd trilayer films was comprehensively investigated. Our studies showed that the hydrogen storage properties of Mg-Pd films were significantly improved with the addition of a Ti interlayer. The optimal hydrogenation properties were obtained when the Ti interlayer was 1 nm. The superior hydrogenation properties achieved by introduction of the Ti interlayer could be attributed to several aspects: prevention of Mg-Pd alloying; catalytic dissociation of H(2) molecules and provision of heterogeneous nucleation sites. These results were elucidative for the development of high performance intermetallic hydrogen storage materials and thin film based functional devices.

Ecosystem services assessment of two watersheds of Lancang River in Yunnan, China with a decision tree approach.

In the Langcang (Upper-Mekong) watershed, degraded watershed ecosystems in upland areas threaten cultivation practices, water resources, and dam development downstream. Assessment of ecosystem services and the factors that threaten them is an important first step to support watershed management. This, however, requires detailed information that is often missing in mountainous regions. To overcome this, in this paper, we adopt a decision tree approach to assess protection, biodiversity, and production services in two mountainous watersheds (Fengqing and Xiaojie) of the Lancang River Basin. Decision tree rules were built on the basis of field surveys, available references, ecosystem maps derived from remote sensing, expert knowledge, basic topographic information, and community interviews. Decision tree results showed that forest cover and agro-forestry practices contribute greatly to improved ecosystem functioning in the Fengqing Catchment compared to the Xiaojie Catchment. The results were consistent with field observations. The decision tree method proved to be a suitable and flexible tool for the rapid assessment of watershed ecosystem services, for highlighting those areas that need more in-depth research, and for guiding watershed and ecosystem management.

[Plant diversity of different replaced communities after Eupatorium adenophorum removal].

Plant diversity of different replaced communities after Eupatorium adenophorum removal. WANG In this paper, an investigation on the structure, species composition and plant diversity of replaced communities after the removal of invasive E. adenophorum at the beginning of 1980s was made in the Shuangbo County of Yunnan Province, with local aged Pinus yunnanensis and unmanaged E. adenophorum forests as the reference. The results showed that in replaced communities, the richness, Shannon-Wiener, Simpson, and Pielou evenness indices values of woody species were 25 to approximately 28, 1.06 to approximately 2.34, 0.36 to approximately 0.86 and 0.32 to approximately 0.73, and those of herb species were 6 to approximately 8, 1.51 to approximately 1.97, 0.74 to approximately 0.84 and 0.84 to approximately 0.90, respectively. In unmanaged E. adenophorum community, the corresponding indices values of woody species were 3, 0.14, 0.10 and 0.13, and those of herb species were 3, 0.09, 0.03 and 0.08, respectively, being much lower than those of the replaced communities. The replaced communities dominated by fast-growing tree species in E. adenophorum forest developed through a 20 years rehabilitation period, under which, there was a clear understory layer dominated by native species. The density and growth rate of E. adenophorum was inhibited in the replaced communities. In comparison with the E. adenophorum community, the plant diversity of replaced communities was greatly increased. Among the replaced communities, P. yunnanensis + Schima wallichii + Eucalyptus globules community had the greatest plant diversity, but the replaced communities had lower plant diversity than the aged P. yunnanensis, with 42, 2.88, 0.92 and 0.77 for woody species, and 8, 2.08, 0.86 and 0.90 for herb species, respectively. It was suggested that more attention should be paid to conserve the rehabilitated communities, especially the P. yunnanensis plantation built on the degraded lands invaded by E. adenophorum. In addition, the introduction of local broad-leaved species and some shade-loving herb plants into these plantations and its follow-up management were also important for the sustainable development of the revegetation.

[Accuracy analysis of vegetation mapping for Meili Snow Mountain area, northwest Yunnan, China].

The Meili Snow Mountain (28 degrees 20'-28 degrees 33'N, 98 degrees 30'-8 degrees 52'E) is a very famous mountain in Northwest Yunnan of China by its rich and well protected biodiversity and Tibetan cultural diversity. By applying 3S (RS-Remote Sensing, GIS-Geography Information System, GPS-Global Position System) technology, the 1:50000 vegetation map of Meili Snow Mountain area (total about 332 km2) was drawn out. The vegetation in this area was classified into 18 vegetation types except for stone, glacier and river system. The vegetation map was rectified by applying the GPS points got from the fields. The numbers of GPS points were calculated by the formula of numbers of samples in statistics. 313 GPS points were used to rectify the vegetation map. The numbers were fit for the formula of numbers of samples in Statistics. The accuracy and verify of vegetation types distribution in the map was analyzed by building a Probability Error Matrix (PEM) and through the variance analysis. The results indicated that the overall accuracy (OA) of the vegetation map was 84.7%. The accuracy of vegetation map finished by 3S technology was lied on the area of the region and the grade of vegetation class first, but the grade of vegetation class classified by remote sensing technology disaccord with the traditional vegetation class system. The other factos deciding the accuracy of vegetation were the distinguish ability of Remote Sensing image, the accuracy of distinguish, and the numbers of the samples, including vegetation class experts knowledge.