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Ajuga bracteosa is an endangered medicinal herb which contains several natural products of therapeutic importance like 20-hydroxyecdysone (20-HE). As geography and habitat play a crucial role in the metabolism and morphology of a plant, the present study was aimed at evaluating the impact of phytogeography, season and tissue type on morphology and 20-HE content of A. bracteosa. The results revealed large morphological variations in various ecotypes of A. bracteosa. However, plants from the same altitude, regardless of their phytogeography, represented similar morphology. Effect of habitat on 20-HE content remained non-significant except for Karot (1608μg/g) and Kahuta (728μg/g). Effect of tissue types was significant (p value <0.016) for 20-HE content and followed ascending order: rootspring (1071μg/g)>summer (617μg/g). The aerial tissue types contained more 20-HE content in all seasons; especially during winter its amount radically rose in flowers (μ=2814μg/g). The aerial portion of Karot ecotype harvested in winter offers a valuable source of 20-HE. To confirm the effect of low temperature on 20-HE content, profiling of A. bracteosa raised in vitro at different temperature regime was carried out. On the basis of these results we hypothesize that chilling cold hampers vegetative growth and triggers stress induced 20-HE accumulation as a defense response., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Invasive plants are often sold as ornamental garden plants, but how often are species sold in the same locations as where they are invasive? To answer this question, we assessed the geography of ornamental plant sales in the United States in relation to existing invasions and potential invasion risk with climate change. Using a data set of 672 nurseries selling 89 invasive plants, we estimated the distance between nursery sales and invasive species' observed distributions. We also used species range maps to identify nursery sales within current potential invaded ranges, as well as within species' future potential ranges given climate change. Half of the species were sold by a nursery within 21 kilometers of an observed record of invasion. Under the current climate, horticulture could be seeding invasions for 73 of the 89 species studied, and horticulture could facilitate climate-driven range expansion of 25 of 89 species. Our results illustrate risks associated with horticultural introductions of invasive species, providing guidance for regulatory and educational interventions that reduce the spread of ongoing and future invasions. [ABSTRACT FROM AUTHOR]

Attention to plant life is currently flourishing across the social sciences and humanities. This paper introduces recent work in the informal sub-discipline of 'vegetal geography', placing it into conversation with the transdisciplinary field of 'critical plant studies' [CPS], a broad framework for re-evaluating plants and human-plant interactions informed by principles of agency, ethics, cognition and language. I explore three key themes of interest to multispecies scholars looking to attend more closely to vegetal life, namely: (1) plant otherness; (2) plant ethics; (3) plant-human attunements, in the hope of encouraging greater cross-pollination between more-than-human geography and critical plant studies. [ABSTRACT FROM AUTHOR]

Large‐scale patterns of biodiversity and formation have garnered increasing attention in biogeography and macroecology. The Qinghai‐Tibet Plateau (QTP) is an ideal area for exploring these issues. However, the QTP consists of multiple geographic subunits, which are understudied. The Kunlun Mountains is a geographical subunit situated in the northern edge of the QTP, in northwest China. The diversity pattern, community phylogenetic structures, and biogeographical roles of the current flora of the Kunlun Mountains were analyzed by collecting and integrating plant distribution, regional geological evolution, and phylogeography. A total of 1911 species, 397 genera, and 75 families present on the Kunlun Mountains, of which 29.8% of the seed plants were endemic to China. The mean divergence time (MDT) of the Kunlun Mountains flora was in the early Miocene (19.40 Ma). Analysis of plant diversity and MDT indicated that the eastern regions of the Kunlun Mountains were the center of species richness, endemic taxa, and ancient taxa. Geographical origins analysis showed that the Kunlun Mountains flora was diverse and that numerous clades were from East Asia and Tethyan. Analysis of geographical origins and geological history together highlighted that the extant biodiversity on the Kunlun Mountains appeared through species recolonization after climatic fluctuations and glaciations during the Quaternary. The nearest taxon index speculated that habitat filtering was the most important driving force for biodiversity patterns. These results suggest that the biogeographical roles of the Kunlun Mountains are corridor and sink, and the corresponding key processes are species extinction and immigration. The Kunlun Mountains also form a barrier, representing a boundary among multiple floras, and convert the Qinghai‐Tibet Plateau into a relatively closed geographical unit. [ABSTRACT FROM AUTHOR]

Due to climate change, plant populations experience environmental conditions to which they are not adapted. Our understanding of the next century's vegetation geography depends on the distance, direction, and rate at which plant distributions shift in response to a changing climate. In this study we test the sensitivity of tree range shifts (measured as the difference between seedling and mature tree ranges in climate space) to wildfire occurrence, using 74,069 Forest Inventory Analysis plots across nine states in the western United States. Wildfire significantly increased the seedling-only range displacement for 2 of the 8 tree species in which seedling-only plots were displaced from tree-plus-seedling plots in the same direction with and without recent fire. The direction of climatic displacement was consistent with that expected for warmer and drier conditions. The greater seedling-only range displacement observed across burned plots suggests that fire can accelerate climate-related range shifts and that fire and fire management will play a role in the rate of vegetation redistribution in response to climate change. Tree species that are expanding their distribution in response to climate change could be hindered or facilitated by disturbances. Here the authors analyse forest inventory data from the western US to test the hypothesis that wildfire can facilitate climate-induced range shifts in trees. [ABSTRACT FROM AUTHOR]

Introduction: Knowledge of species richness patterns and their relation with climate is required to develop various forest management actions including habitat management, biodiversity and risk assessment, restoration and ecosystem modelling. In practice, the pattern of the data might not be spatially constant and cannot be well addressed by ordinary least square (OLS) regression. This study uses GWR to deal with spatial non-stationarity and to identify the spatial correlation between the plant richness distribution and the climate variables (i.e., the temperature and precipitation) in a 1° grid in different biogeographic zones of India. Methodology: We utilized the species richness data collected using 0.04 ha nested quadrats in an Indian study. The data from this national study, titled ‘Biodiversity Characterization at Landscape Level’, were aggregated at the 1° grid level and adjudged for sampling sufficiency. The performances of OLS and GWR models were compared in terms of the coefficient of determination (R2) and the corrected Akaike Information Criterion (AICc). Results and discussion: A comparative study of the R2 and AICc values of the models showed that all the GWR models performed better compared with the analogous OLS models. The climate variables were found to significantly influence the distribution of plant richness in India. The minimum precipitation (Pmin) consistently dominated individually (R2 = 0.69; AICc = 2608) and in combinations. Among the shared models, the one with a combination of Pmin and Tmin had the best model fits (R2 = 0.72 and AICc = 2619), and variation partitioning revealed that the influence of these parameters on the species richness distribution was dominant in the arid and the semi-arid zones and in the Deccan peninsula zone. Conclusion: The shift in climate variables and their power to explain the species richness of biogeographic zones suggests that the climate–diversity relationships of plants species vary spatially. In particular, the dominant influence of Tmin and Pmin could be closely linked to the climate tolerance hypothesis (CTH). We found that the climate variables had a significant influence in defining species richness patterns in India; however, various other environmental and non-environmental (edaphic, topographic and anthropogenic) variables need to be integrated in the models to understand climate–species richness relationships better at a finer scale. [ABSTRACT FROM AUTHOR]

Soil is one of the most complex systems on Earth, functioning at the interface between the lithosphere, biosphere, hydrosphere, and atmosphere and generating a multitude of functions. Moreover, soil constitutes the belowground environment from which plants capture water and nutrients. Despite their great importance, soil properties are often not sufficiently considered in other disciplines, especially in spatial studies of plant distributions. Most soil properties are available as point data and, to be used in spatial analyses, need to be generalised over entire regions (i.e. digital soil mapping). Three categories of statistical approaches can be used for such purpose: geostatistical approaches (GSA), predictive-statistical approaches (PSA), and hybrid approaches (HA) that combine the two previous ones. How then to choose the best approach in a given soil study context? Does it depend on the soil properties to be spatialized, the study area’s characteristics, and/or the availability of soil data? The main aims of this study was to review the use of these three approaches to derive maps of soil properties in relation to the soil parameters, the study area characteristics, and the number of soil samples. We evidenced that the approaches that tend to show the best performance for spatializing soil properties were not necessarily the ones most used in practice. Although PSA was the most widely used, it tended to be outperformed by HA in many cases, but the latter was far less used. However, as the study settings were not always properly described and not all situations were represented in the set of papers analysed, more comparative studies would be needed across a wider range of regions, soil properties, and spatial scales to provide robust conclusions on the best spatialization methods in a specific context. [ABSTRACT FROM AUTHOR]

Climate change is affecting the growth, phenology, and distribution of species across northeastern United States. In response to these changes, some species have been adversely impacted while others have benefited. One species that has benefited from climate change, historically and in response to experimental treatments, is common ragweed (Ambrosia artemisiifolia), a widely distributed annual weed and a leading cause of hay fever in North America. To better understand how climate change may affect the distribution of common ragweed, we built a maximum entropy (Maxent) predictive model using climate and bioclimatic data and over 700 observations across the eastern U.S. Our model performed well with an AUC score of 0.765 using four uncorrelated variables, including precipitation seasonality, mean diurnal temperature range, August precipitation, and January maximum temperature. After building and testing our model, we then projected potential future common ragweed distribution using a suite of 13 global climate models (GCMs) under two future greenhouse gas scenarios for mid and late-century. In addition to providing georeferenced hot spots of potential future expansion, we also provide a metric of confidence by evaluating the number of GCMs that agree. We show a substantial contraction of common ragweed in central Florida, southern Appalachian Mountains, and northeastern Virginia and areas of potential expansion at the northern margins of its current distribution, notably in northeastern U.S. However, the vast majority of this increase is projected to occur by mid-century and may be moderated somewhat by the 2070s, implying that common ragweed may be sensitive to climatic variability. Although other factors and modeling approaches should be explored, we offer preliminary insight into where common ragweed might be a new concern in the future. Due to the health impacts of ragweed, local weed control boards may be well advised to monitor areas of expansion and potentially increase eradication efforts. [ABSTRACT FROM AUTHOR]

Secale L. is a small but important genus that includes cultivated rye. Although genetic diversity of cultivated rye is high, patterns of genetic diversity in the whole genus, and potential factors affecting the distribution of genetic diversity remain elusive. The population structure and distribution of genetic variation within Secale, and its correlation with taxonomic delimitation, cultivation status or spatial distribution in relation to geography and climate zones were analyzed in this study. A collection of 726 individual plants derived from 139 different accessions representing Secale cereale, S. vavilovii, S. strictum, and S. sylvestre were investigated using SSR analysis and sequence diversity analysis of a nuclear EST region. Our results indicated that perennial S. strictum subspecies are genetically divergent from annual forms of the genus. Existence of two distinct clusters within the annual taxa was observed, one corresponding to samples from Asia, and a second to those outside of Asia. No clear genetic structure was observed between different annual species/subspecies, indicating introgression between these taxa. The analysis of cultivated rye revealed that landrace populations from the Middle East have the highest genetic diversity, supporting the idea of the area being the center of origin for cultivated rye. Considering high adaptive potential of those populations, Middle Eastern landraces should be regarded as genetic resources reservoirs for new niches and future breeding programs. [ABSTRACT FROM AUTHOR]

Low temperature is one of the important limiting factors for growing season and geographical distribution of plants. Zoysiagrass (Zoysia Willd) is one of the widely used warm-season turfgrass that is distribute in many parts of the world. Zoysaigrass native to high latitude may have evolved higher cold tolerance than the ones native to low latitude. The objective of this study was to investigate the cold stress response in zoysiagrass native to diverse latitude at phenotypic, physiological and metabolic levels. Two zoysiagrass (Z. japonica) genotypes, Latitude-40 (higher latitude) and Latitude-22 (lower latitude) were subjected to four temperature treatments (optimum, 30/25°C, day/night; suboptimum, 18/12°C; chilling, 8/2°C; freezing, 2/-4°C) progressively in growth chambers. Low temperature (chilling and freezing) increased leaf electrolyte leakage (EL) and reduced plant growth, turf quality, chlorophyll (Chl) content, photochemical efficiency (Fv/Fm) and photosynthesis (Pn, net photosynthetic rate; gs, stomatal conductance; intercellular CO2; Tr, transpiration rate) in two genotypes, with more rapid changes in Latitude-22. Leaf carbohydrates content (glucose, fructose, sucrose, trehalose, fructan, starch) increased with the decreasing of temperature, to a great extend in Latitude-40. Leaf abscisic acid (ABA), salicylic acid (SA) and jasmonic acid (JA) content increased, while indole-3-acetic acid (IAA), gibberellic acid (GA3) and trans-zeatin ribside (t-ZR) content decreased with the reduction of temperature, with higher content in Latitude-40 than in Latitude-22. Chilling and freezing induced the up-regulation of C-repeat binding factor (ZjCBF), late embryogenesis abundant (ZjLEA3) and dehydration-responsive element binding (ZjDREB1) transcription factors in two genotypes, whereas those genes exhibited higher expression levels in Latitude-40, particularly under freezing temperature. These results suggested that zoysiagrass native to higher latitude exhibited higher freezing tolerance may attribute to the higher carbohydrates serving as energy reserves and stress protectants that stabilize cellular membranes. The phytohormones may serve signals in regulating plant growth, development and adaptation to low temperature as well as inducing the up-regulated ZjCBF, ZjLEA3 and ZjDREB1 expressions thus result in a higher cold tolerance. [ABSTRACT FROM AUTHOR]

Like many other high elevation alpine tree species, Rocky Mountain bristlecone pine (Pinus aristata Engelm.) may be particularly vulnerable to climate change. To evaluate its potential vulnerability to shifts in climate, we defined the suitable climate space for each of four genetic lineages of bristlecone pine and for other subalpine tree species in close proximity to bristlecone pine forests. Measuring changes in the suitable climate space for lineage groups is an important step beyond models that assume species are genetically homogenous. The suitable climate space for bristlecone pine in the year 2090 is projected to decline by 74% and the proportional distribution of suitable climate space for genetic lineages shifts toward those associated with warmer and wetter conditions. The 2090 climate space for bristlecone pine exhibits a bimodal distribution along an elevation gradient, presumably due to the persistence of the climate space in the Southern Rocky Mountains and exclusion at mid-elevations by conditions that favor the climate space of other species. These shifts have implications for changes in fire regimes, vulnerability to pest and pathogens, and altered carbon dynamics across the southern Rockies, which may reduce the likelihood of bristlecone pine trees achieving exceptional longevity in the future. The persistence and expansion of climate space for southern bristlecone pine genetic lineage groups in 2090 suggests that these sources may be the least vulnerable in the future. While these lineages may be more likely to persist and therefore present opportunities for proactive management (e.g., assisted migration) to maintain subalpine forest ecosystem services in a warmer world, our findings also imply heighted conservation concern for vulnerable northern lineages facing range contractions. [ABSTRACT FROM AUTHOR]

Avena ventricosa Balansa ex Coss. is considered the C-genome donor of the cultivated hexaploid oat and is a ‘priority’ species for conservation, since it has limited geographic distribution and the only recorded populations in Europe are present in Cyprus. The current study attempts to characterize the genetic structure and fragmentation of the species via the application of genotypic markers. It was revealed that the genetic variety was mainly allocated among the populations collected, since clustering obtained was according to the geographic origin of the samples and the habitat. Species distribution modeling showed that the most important climatic variable defining A. ventricosa distribution is the mean diurnal temperature. Furthermore, significant association of the genetic structure to environmental variables was detected; overall, a negative association to precipitation was confirmed, while significant correlations of genetic structure and the temperature at the time of anthesis and germination were established. The safeguarding of this valuable genetic resource is discussed. [ABSTRACT FROM AUTHOR]

To optimize ecosystem services provided by agricultural drainage networks (ditches) in headwater catchments, we need to manage the spatial distribution of plant species living in these networks. Geomorphological variables have been shown to be important predictors of plant distribution in other ecosystems because they control the water regime, the sediment deposition rates and the sun exposure in the ditches. Whether such variables may be used to predict plant distribution in agricultural drainage networks is unknown. We collected presence and absence data for 10 herbaceous plant species in a subset of a network of drainage ditches (35 km long) within a Mediterranean agricultural catchment. We simulated their spatial distribution with GLM and Maxent model using geomorphological variables and distance to natural lands and roads. Models were validated using k-fold cross-validation. We then compared the mean Area Under the Curve (AUC) values obtained for each model and other metrics issued from the confusion matrices between observed and predicted variables. Based on the results of all metrics, the models were efficient at predicting the distribution of seven species out of ten, confirming the relevance of geomorphological variables and distance to natural lands and roads to explain the occurrence of plant species in this Mediterranean catchment. In particular, the importance of the landscape geomorphological variables, ie the importance of the geomorphological features encompassing a broad environment around the ditch, has been highlighted. This suggests that agro-ecological measures for managing ecosystem services provided by ditch plants should focus on the control of the hydrological and sedimentological connectivity at the catchment scale. For example, the density of the ditch network could be modified or the spatial distribution of vegetative filter strips used for sediment trapping could be optimized. In addition, the vegetative filter strips could constitute new seed bank sources for species that are affected by the distance to natural lands and roads. [ABSTRACT FROM AUTHOR]

Oxalis pes-caprae L. is a South African geophyte that behaves as an invasive in the eurimediterranean area. According to a long-established hypothesis, O. pes-caprae may have invaded Europe and the Mediterranean area starting from a single plant introduced in the Botanical Garden of Malta at the beginning of the 19th century. The aim of this work was to test this hypothesis, to track the arrival of O. pes-caprae in different countries of the Euro-Mediterranean area and to understand the pathways of spreading and particularly its starting point(s). Historical data attesting the presence of the plant in the whole Euro-Mediterranean region were collected from different sources: herbarium specimens, Floras and other botanical papers, plant lists of gardens, catalogs of plant nurseries and plant dealers. First records of the plant (both cultivated and wild) for each Territorial Unit (3rd level of NUTS) were selected and used to draw up a diachronic map and an animated graphic. Both documents clearly show that oldest records are scattered throughout the whole area, proving that the plant arrived in Europe and in the Mediterranean region more times independently and that its spreading started in different times from several different centers of invasion. Botanical gardens and other public or private gardens, nurseries and plant dealers, and above all seaside towns and harbors seemingly played a strategic role as a source of either intentional and unintentional introduction or spread. A geographic profiling analysis was performed to analyse the data. We used also techniques (Silhouette, Kmeans and Voronoi tessellation) capable of verifying the presence of more than one independent clusters of data on the basis of their geographical distribution. Microsatellites were employed for a preliminary analysis of genetic variation in the Mediterranean. Even if the sampling was insufficient, particularly among the populations of the original area, our data supported three main groups of populations, one of them corresponding to the central group of populations identified by GP analysis, and the other two corresponding, respectively, to the western and the eastern cluster of data. The most probable areas of origin of the invasion in the three clusters of observations are characterized by the presence of localities where the invasive plant was cultivated, with the exception of the Iberian cluster of observation where the observations in the field predate the data about known cultivation localities. Alternative possible reasons are also suggested, to explain the current prevalence of pentaploid short-styled plants in the Euro-Mediterranean area. [ABSTRACT FROM AUTHOR]

Machilus pauhoi Kanehira is an important timber species in China. A provenance trial was recently set up to evaluate the growth performance of trees from different localities, with the aim of designing seed transfer guidelines. Here, we tested twelve nuclear microsatellite markers derived from other species of the Lauraceae family and investigated population genetic structure in M. pauhoi. Both the number of observed alleles per locus (Na) and the polymorphic information content (PIC) significantly decreased against the latitude, but showed an insignificant decrease against the longitude. Heterozygosity (Ho) and gene diversity (h) exhibited a weak correlation with geographic location. Private alleles were present in multiple populations, and a moderate level of population genetic differentiation was detected (Gst = 0.1691). The joint pattern of genetic diversity (Na, PIC, Ho, and h) suggests that general northeastward dispersal led to the current distribution of M. pauhoi. Significant but weak effects of isolation-by-distance (IBD) occurred, implicating the mountain ranges as the major barrier to gene flow. Both STRUCTURE and hierarchical clustering analyses showed three distinct groups of populations related to the physical connectivity among mountain ranges. A priority in designing genetic conservation should be given to the populations at the southwest side of the species’ distribution. This conservation strategy can also be combined with the pattern of adaptive genetic variation from the provenance trial for comprehensive genetic resource management of native M. pauhoi. [ABSTRACT FROM AUTHOR]

This study analyzed the characteristics of Korean pine (Pinus koraiensis) functional trait responses to geographic and climatic factors in the eastern region of Northeast China (41°–48°N) and the linear relationships among Korean pine functional traits, to explore this species’ adaptability and ecological regulation strategies under different environmental conditions. Korean pine samples were collected from eight sites located at different latitudes, and the following factors were determined for each site: geographic factors—latitude, longitude, and altitude; temperature factors—mean annual temperature (MAT), growth season mean temperature (GST), and mean temperature of the coldest month (MTCM); and moisture factors—annual precipitation (AP), growth season precipitation (GSP), and potential evapotranspiration (PET). The Korean pine functional traits examined were specific leaf area (SLA), leaf thickness (LT), leaf dry matter content (LDMC), specific root length (SRL), leaf nitrogen content (LNC), leaf phosphorus content (LPC), root nitrogen content (RNC), and root phosphorus content (RPC). The results showed that Korean pine functional traits were significantly correlated to latitude, altitude, GST, MTCM, AP, GSP, and PET. Among the Korean pine functional traits, SLA showed significant linear relationships with LT, LDMC, LNC, LPC, and RPC, and LT showed significant linear relationships with LDMC, SRL, LNC, LPC, RNC, and RPC; the linear relationships between LNC, LPC, RNC, and RPC were also significant. In conclusion, Korean pine functional trait responses to latitude resulted in its adaptation to geographic and climatic factors. The main limiting factors were precipitation and evapotranspiration, followed by altitude, latitude, GST, and MTCM. The impacts of longitude and MAT were not obvious. Changes in precipitation and temperature were most responsible for the close correlation among Korean pine functional traits, reflecting its adaption to habitat variation. [ABSTRACT FROM AUTHOR]

The flora of Laos is composed of 5,005 species in 1,373 genera and 188 families of seed plants. Floristic and geographical attributes of the flora were analyzed. Tropical floristic elements at the family and generic levels contributed a majority (62.23% of the families and 82.30% of the genera) of the flora, of which the dominant geographical elements were pantropical distribution (42.02% of families) and tropical Asian distribution (30.08% of genera). This revealed that the flora of Lao PDR is tropical in nature and has a conspicuously tropical Asian affinity. Compared with the neighbouring countries of the Indochina peninsula, the flora of Laos has similar floristic composition and geographical elements. The floras of these Indochinese countries have similarities of more than 77.84% at the generic level, which suggests that they compose an affiliated biogeographical region. However, the flora of Laos showed the highest similarity to the flora of Vietnam (92.13%), followed by Myanmar (86.01%) at the generic level, but has less East Asian and North Temperate elements than Vietnam, and less North Temperate elements than Myanmar. These differences among the compared countries could be explained by the extrusion of the Indochinese block with the uplift of the Himalayas. [ABSTRACT FROM AUTHOR]

Aim: To test whether novel and previously hypothesized biogeogaphic barriers in the Australian Tropics represent significant disjunction points or hard barriers, or both, to the distribution of plants. Location: Australian tropics: Australian Monsoon Tropics and Australian Wet Tropics. Methods: The presence or absence of 6,861 plant species was scored across 13 putative biogeographic barriers in the Australian Tropics, including two that have not previously been recognised. Randomizations of these data were used to test whether more species showed disjunctions (gaps in distribution) or likely barriers (range limits) at these points than expected by chance. Results: Two novel disjunctions in the Australian Tropics flora are identified in addition to eleven putative barriers previously recognized for animals. Of these, eleven disjunction points (all within the Australian Monsoon Tropics) were found to correspond to range-ending barriers to a significant number of species, while neither of the two disjunctions found within the Australian Wet Tropics limited a significant number of species’ ranges. Main conclusions: Biogeographic barriers present significant distributional limits to native plant species in the Australian Monsoon Tropics but not in the Australian Wet Tropics. [ABSTRACT FROM AUTHOR]

Varying patterns of plant community diversity along geographical gradients are a significant topic in biodiversity research. Here, to explore the integrated effects of latitude and altitude on the plant community diversity in a mountainous ecosystem, we set Guancen Mountain in the northern section, Guandi Mountain in the middle section, and Wulu Mountain in the southern section of the Lvliang Mountains as study areas, and the plant community diversity (basal diameter and height of tree and species diversity indices of shrub and herb) was measured horizontally at different latitude gradients and vertically at different altitude gradients in late July 2015. The results showed that (1) the trees were taller and wider at the middle latitude and higher altitude with a stronger spatial heterogeneity in the structures along the latitudinal and altitudinal gradients. The evergreen tree growth preceded that of the deciduous trees in the higher latitude and lower altitude regions, whereas the deciduous tree growth preceded that of the evergreen trees in the middle latitude and higher altitude regions. (2) Shrubs and herbs tended to grow well in the lower latitude and middle-lower altitude regions. The shrubs had a larger species diversity at lower latitude and lower altitude, but the species diversity of the herbs was not sensitive to the influences of the latitudinal and altitudinal gradients. With the latitude and altitude increasing, perennial herbs tended to grow well at higher latitude and higher altitude, while annual herbs tended to thrive at the middle latitude and lower altitude. In conclusion, environmental deviations caused by latitudinal and altitudinal gradients had great influences on the spatial distributions of the plant community diversity in the Lvliang Mountains. [ABSTRACT FROM AUTHOR]

Based on a great number of literatures, we established the database about the Chinese endemic seed plants and analyzed the compositions, growth form, distribution and angiosperm original families of them within three big natural areas and seven natural regions. The results indicate that the above characters of Chinese endemic plants take on relative rule at the different geographical scales. Among the three big natural areas, Eastern Monsoon area has the highest endemic plants richness, whereas Northwest Dryness area is the lowest. For life forms, herbs dominate. In contrast, the proportion of herbs of Eastern Monsoon area is remarkable under other two areas. Correspondingly the proportions of trees and shrubs are substantially higher than other two. For angiosperm original families, the number is the highest in Eastern Monsoon area, and lowest in Northwest Dryness area. On the other hand, among the seven natural regions, the humid and subtropical zone in Central and Southern China has the highest endemic plants richness, whereas the humid, hemi-humid region and temperate zone in Northeast China has the lowest. For life forms, the proportion of herbs tends to decrease from humid, hemi-humid region and temperate zone in Northeast China to humid and tropical zone in Southern China. Comparably, trees, shrubs and vines or lianas increase with the same directions. This fully represents these characters of Chinese endemic plants vary with latitudinal gradients. Furthermore, as to the number of endemic plants belonging to angiosperm original families, the number is the most in humid and subtropical zone in Center and Southern China, and tropical zone in Southern China in the next place. In contrast, the endemic plant of these two regions relatively is richer than that of The Qinghai-Tibet alpine and cold region. All above results sufficiently reflect that the Chinese endemic plants mainly distribute in Eastern Monsoon area, especially humid and subtropical zone in Center and Southern China and tropical zone in Southern China. Furthermore, the flora of Eastern Monsoon area, in particular humid and subtropical zone in Center and Southern China and tropical zone in Southern China, is more ancient and original than that of Northwest Dryness area and Qinghai-Tibet alpine and cold area. [ABSTRACT FROM AUTHOR]

Until now, little attention has been paid to the geographic distribution and evaluation of genetic diversity of durum wheat from the Central Fertile Crescent (modern-day Turkey and Syria). Turkey and Syria are considered as primary centers of wheat diversity, and thousands of locally adapted wheat landraces are still present in the farmers’ small fields. We planned this study to evaluate the genetic diversity of durum wheat landraces from the Central Fertile Crescent by genotyping based on DArTseq and SNP analysis. A total of 39,568 DArTseq and 20,661 SNP markers were used to characterize the genetic characteristic of 91 durum wheat land races. Clustering based on Neighbor joining analysis, principal coordinate as well as Bayesian model implemented in structure, clearly showed that the grouping pattern is not associated with the geographical distribution of the durum wheat due to the mixing of the Turkish and Syrian landraces. Significant correlation between DArTseq and SNP markers was observed in the Mantel test. However, we detected a non-significant relationship between geographical coordinates and DArTseq (r = -0.085) and SNP (r = -0.039) loci. These results showed that unconscious farmer selection and lack of the commercial varieties might have resulted in the exchange of genetic material and this was apparent in the genetic structure of durum wheat in Turkey and Syria. The genomic characterization presented here is an essential step towards a future exploitation of the available durum wheat genetic resources in genomic and breeding programs. The results of this study have also depicted a clear insight about the genetic diversity of wheat accessions from the Central Fertile Crescent. [ABSTRACT FROM AUTHOR]

The influence of geographic range on species persistence has long been of interest and there is a need for a better understanding of the genetic consequences for species with restricted distributions, particularly with the increasing rate of global species extinctions. However, the genetic effects of restricted range are often confounded by the impacts of population distribution. We compared chloroplast and nuclear genetic diversity and differentiation in two acacias, the restricted, patchily distributed Acacia atkinsiana and the widespread, semi-continuously distributed A. ancistrocarpa. Lower intra-population diversity and higher differentiation between populations were seen in A. atkinsiana compared to its widespread congener, A. ancistrocarpa. There was little evidence of geographical influences on population genetic structure in A. ancistrocarpa whereas A. atkinsiana exhibited nuclear genetic structure with isolation by distance, differentiation of near-coastal populations from those in the ranges, and differentiation of peripheral populations from those in the centre of the distribution. These results are consistent with expectations of the effect of geographic range and population distribution on genetic diversity, but indicate that distribution of populations rather than geographic range has influenced the observed genetic structure. The contrasting patterns observed here demonstrate that conservation approaches for species management and ecological restoration need to consider the distribution of populations in geographically restricted species. [ABSTRACT FROM AUTHOR]

Background: Habitat fragmentation, water resources and biological characteristics are important factors that shape the genetic structure and geographical distribution of desert plants. Analysis of the relationships between these factors and population genetic variation should help to determine the evolutionary potential and conservation strategies for genetic resources for desert plant populations. As a traditional Chinese herb, Glycyrrhiza inflata B. (Fabaceae) is restricted to the fragmented desert habitat in China and has undergone a dramatic decline due to long-term over-excavation. Determining the genetic structure of the G. inflata population and identifying a core collection could help with the development of strategies to conserve this species. Results: We investigated the genetic variation of 25 G. inflata populations based on microsatellite markers. A high level of population genetic divergence (FST = 0.257), population bottlenecks, reduced gene flow and moderate genetic variation (HE = 0.383) were detected. The genetic distances between the populations significantly correlated with the geographical distances, and this suggests that habitat fragmentation has driven a special genetic structure of G. inflata in China through isolation by distance. STRUCTURE analysis showed that G. inflata populations were structured into three clusters and that the populations belonged to multiple water systems, which suggests that water resources were related to the genetic structure of G. inflata. In addition, the biological characteristics of the perennial species G. inflata, such as its long-lived seeds, asexual reproduction, and oasis ecology, may be related to its resistance to habitat fragmentation. A core collection of G. inflata, that included 57 accessions was further identified, which captured the main allelic diversity of G. inflata. Conclusions: Recent habitat fragmentation has accelerated genetic divergence. The population genetic structure of G. inflata has been shaped by habitat fragmentation, water resources and biological characteristics. This genetic information and core collection will facilitate the conservation of wild germplasm and breeding of this Chinese medicinal plant. [ABSTRACT FROM AUTHOR]

The flowering plant family Elatinaceae is a widespread aquatic lineage inhabiting temperate and tropical latitudes, including ∼35(-50) species. Its phylogeny remains largely unknown, compromising our understanding of its systematics. Moreover, this group is particularly in need of attention because the biogeography of most aquatic plant clades has yet to be investigated, resulting in uncertainty about whether aquatic plants show histories that deviate from terrestrial plants. We inferred the phylogeny of Elatinaceae from four DNA regions spanning 59 accessions across the family. An expanded sampling was used for molecular divergence time estimation and ancestral area reconstruction to infer the biogeography of Elatinaceae and their closest terrestrial relatives, Malpighiaceae and Centroplacaceae. The two genera of Elatinaceae, Bergia and Elatine, are monophyletic, but several traditionally recognized groups within the family are non-monophyletic. Our results suggest two ancient biogeographic events in the Centroplacaceae(Malpighiaceae, Elatinaceae) clade involving western Gondwana, while Elatinaceae shows a more complicated biogeographic history with a high degree of continental endemicity. Our results indicate the need for further taxonomic investigation of Elatinaceae. Further, our study is one of few to implicate ancient Gondwanan biogeography in extant angiosperms, especially significant given the Centroplacaceae(Malpighiaceae, Elatinaceae) clade's largely tropical distribution. Finally, Elatinaceae demonstrates long-term continental in situ diversification, which argues against recent dispersal as a universal explanation commonly invoked for aquatic plant distributions. [ABSTRACT FROM AUTHOR]

Tintinnids are planktonic ciliates that play an important role in marine ecosystem. According to their distribution in the world oceans, tintinnid genera were divided into several biogeographical types such as boreal, warm water, austral and neritic. Therefore, the oceanic tintinnid assemblage could be correspondingly divided into boreal assemblage, warm water assemblage and austral assemblage. The purpose of this study was to investigate the characteristics of boreal tintinnid assemblage in the Northwest Pacific and the Arctic, and to identify the connection between boreal tintinnid assemblage and neighboring assemblages. Surface water samples were collected along a transect from the East China Sea to the Chukchi Sea in summer 2014. According to the presence of boreal genera and warm water genera, three tintinnid assemblages (the East China Sea neritic assemblage, the Japan Sea warm water assemblage, and the boreal assemblage) were identified along the transect. The boreal assemblage extended from the Chukchi Sea to the waters north of the Sōya Strait. Densities peaks occurred at stations in the two branches of the Alaska Current and decreased both northward and southward. The densities were <10 ind./dm3 at most stations in Arctic region. The dominant genera (Acanthostomella, Codonellopsis, Parafavella, and Ptychocylis) accounted for 79.07±29.67% (n = 49) of the abundance in the boreal assemblage. The densities of the dominant genera covaried with strongly significant positive correlations. Tintinnids with lorica oral diameter of 22–26 μm and 38–42 μm were dominant and contributed 67.35% and 15.13%, respectively, to the total abundance in the boreal assemblage. The distribution and densities of tintinnids in the study area suggest that the Sōya Strait might be a geographical barrier for tintinnids expansion. [ABSTRACT FROM AUTHOR]

Both the continental or island origin of Hainan, and the Indo-Malaysian or East Asian affinity of its flora, are debatable. In this study, 196 families, 1283 genera and 3894 species of Hainan plants were recognized. Patterns of seed plant distribution were quantified at the generic and the family levels. The floras of Vietnam, and the adjacent Guangxi and Guangdong provinces of mainland China, were compared with Hainan. The results showed that the flora of Hainan Island is dominated by families and genera with tropical distributions. Among its floristic elements, tropical Asian distributions make up 23.85% of the total flora, while East Asian distributions contribute only 3.74%. There are only 7 genera and c. 10% of species endemic to Hainan Island. The Hainan flora has strong similarities to the flora of Vietnam at the family and the generic levels, and also to the flora of Guangxi, but less with the adjacent Guangdong province. The main conclusions are: Hainan’s flora is tropical in nature with a strongly tropical Asian affinity, and it has very low endemism at the generic and species levels, which implies a continental origin. We conjecture that Hainan Island could have been adjacent to northern Vietnam and the Guangxi at least in Eocene. This suggestion is supported by palaeobotanical, palaeomagnetic and volcanism studies. [ABSTRACT FROM AUTHOR]

Background: The distribution of genetic variability from the interior towards the periphery of a species’ range is of great interest to evolutionary biologists. Although it has been long presumed that population genetic variation should decrease as a species’ range is approached, results of empirical investigations still remain ambiguous. Knowledge regarding patterns of genetic variability as well as affected factors is particularly not conclusive in plants. Methodology/Principal Findings: To determine genetic divergence in peripheral populations of the wild rice Oryza rufipogon Griff. from China, genetic diversity and population structure were studied in five northern & northeastern peripheral and 16 central populations using six microsatellite loci. We found that populations resided at peripheries of the species possessed markedly decreased microsatellite diversity than those located in its center. Population size was observed to be positively correlated with microsatellite diversity. Moreover, there are significantly positive correlations between levels of microsatellite diversity and distances from the northern and northeastern periphery of this species. To investigate genetic structure and heterozygosity variation between generations of O. rufipogon, a total of 2382 progeny seeds from 186 maternal families were further assayed from three peripheral and central populations, respectively. Peripheral populations exhibited significantly lower levels of heterozygosities than central populations for both seed and maternal generations. In comparisons with maternal samples, significantly low observed heterozygosity (HO) and high heterozygote deficit within populations (FIS) values were detected in seed samples from both peripheral and central populations. Significantly lower observed heterozygosity (HO) and higher FIS values were further observed in peripheral populations than those in central populations for seed samples. The results indicate an excess of homozygotes and thus high inbreeding depression in peripheral populations. Conclusions/Significance: Our results together suggest that historical contraction of geographical range, demographic changes, and environmental conditions near the northern and northeastern margins of O. rufipogon favor inbreeding and possibly selfing, leading to the rapidly decreased effective population size. Genetic drift, reduced gene flow, and possible local selection, consequently lead to lowered gene diversity, accelerated genetic divergence and increased inbreeding depression found in peripheral populations of O. rufipogon. Given these characteristics observed, northern and northeastern peripheral populations deserve relatively different conservation strategies for either germplasm sampling of ex situ conservation or setting in situ reserves for the adaptation to possible environmental changes and the future germplasm utilization of wild rice. [ABSTRACT FROM AUTHOR]

Hydrological alternation can dramatically influence riparian environments and shape riparian vegetation zonation. However, it was difficult to predict the status in the drawdown area of the Three Gorges Reservoir (TGR), because the hydrological regime created by the dam involves both short periods of summer flooding and long-term winter impoundment for half a year. In order to examine the effects of hydrological alternation on plant diversity and biomass in the drawdown area of TGR, twelve sites distributed along the length of the drawdown area of TGR were chosen to explore the lateral pattern of plant diversity and above-ground biomass at the ends of growing seasons in 2009 and 2010. We recorded 175 vascular plant species in 2009 and 127 in 2010, indicating that a significant loss of vascular flora in the drawdown area of TGR resulted from the new hydrological regimes. Cynodon dactylon and Cyperus rotundus had high tolerance to short periods of summer flooding and long-term winter flooding. Almost half of the remnant species were annuals. Species richness, Shannon-Wiener Index and above-ground biomass of vegetation exhibited an increasing pattern along the elevation gradient, being greater at higher elevations subjected to lower submergence stress. Plant diversity, above-ground biomass and species distribution were significantly influenced by the duration of submergence relative to elevation in both summer and previous winter. Several million tonnes of vegetation would be accumulated on the drawdown area of TGR in every summer and some adverse environmental problems may be introduced when it was submerged in winter. We conclude that vascular flora biodiversity in the drawdown area of TGR has dramatically declined after the impoundment to full capacity. The new hydrological condition, characterized by long-term winter flooding and short periods of summer flooding, determined vegetation biodiversity and above-ground biomass patterns along the elevation gradient in the drawdown area. [ABSTRACT FROM AUTHOR]

Geographic barriers and Quaternary climate changes are two major forces driving the evolution, speciation, and genetic structuring of extant organisms. In this study, we used Pinus armandii and eleven other Asian white pines (subsection Strobus, subgenus Pinus) to explore the influences of geographic factors and Pleistocene climatic oscillations on species in South China, a region known to be centers of plant endemism and biodiversity hotspots. Range-wide patterns of genetic variation were investigated using chloroplast and mitochondrial DNA markers, with extensive sampling throughout the entire range of P. armandii. Both cpDNA and mtDNA revealed that P. armandii exhibits high levels of genetic diversity and significant population differentiation. Three geographically distinct subdivisions corresponding to the Qinling-Daba Mountains (QDM), Himalaya-Hengduan Mountains (HHM) and Yungui Plateau (YGP) were revealed in mainland China by cpDNA. Their break zone was located in the southeastern margin of the Qinghai-Tibetan Plateau (QTP). A series of massive mountains, induced by the QTP uplift, imposed significant geographic barriers to genetic exchange. The disjunct distribution patterns of ancestral haplotypes suggest that a large continuous population of the white pines may have existed from southwest to subtropical China. Repeated range shifts in response to the Pleistocene glaciations led to the isolation and diversification of the subtropical species. The two Taiwanese white pines share a common ancestor with the species in mainland China and obtain their chloroplasts via long-distance pollen dispersal from North Asian pines. Distinct genetic patterns were detected in populations from the Qinling-Daba Mountains, Yungui Plateau, Himalaya-Hengduan Mountains, and subtropical China, indicating significant contributions of geographic factors to the genetic differentiation in white pines. Our study depicts a clear picture of the evolutionary history of Chinese white pines and highlights the heterogeneous contributions of geography and Pleistocene climatic fluctuations to the extremely high plant species diversity and endemism in South China. [ABSTRACT FROM AUTHOR]

Phytophthora ramorum, an invasive plant pathogen of unknown origin, causes considerable and widespread damage in plant industries and natural ecosystems of the USA and Europe. Estimating the potential geographical range of P. ramorum has been complicated by a lack of biological and geographical data with which to calibrate climatic models. Previous attempts to do so, using either invaded range data or surrogate species approaches, have delivered varying results. A simulation model was developed using CLIMEX to estimate the global climate suitability patterns for establishment of P. ramorum. Growth requirements and stress response parameters were derived from ecophysiological laboratory observations and site-level transmission and disease factors related to climate data in the field. Geographical distribution data from the USA (California and Oregon) and Norway were reserved from model-fitting and used to validate the models. The model suggests that the invasion of P. ramorum in both North America and Europe is still in its infancy and that it is presently occupying a small fraction of its potential range. Phytophthora ramorum appears to be climatically suited to large areas of Africa, Australasia and South America, where it could cause biodiversity and economic losses in plant industries and natural ecosystems with susceptible hosts if introduced. [ABSTRACT FROM AUTHOR]

The geographic and host distributions of Arceuthobium hondurense and A. nigrum (Viscaceae) in southern Mexico and Central America have remained unclear due to difficulties in their identification. This study was conducted to clarify the morphology, phenology, distribution, and host affinities of these dwarf mistletoes. Morphological measurements were made for these species across their geographic distributions and nr ITS sequences were generated and compared from selected populations in Mexico. Although subtle, interspecific differences in plant morphology were found, A. hondurense and A. nigrum can be differentiated by the dimensions of their staminate spikes, staminate flowers, and fruits. Our data also indicated that A. hondurense and A. nigrum were not sympatric. Arceuthobium hondurense is distributed from northern Nicaragua to northern Oaxaca, Mexico and A. nigrum is distributed from Veracruz to northern Durango. Although A. hondurense and A. nigrum flowered in the fall, A. hondurense consistently peaked in September and A. nigrum peaked in October, extending into January in central Mexico. A spring flowering period reported previously for A. nigrum was not observed. Additional information on the host distribution and molecular differences of these dwarf mistletoes is also presented. [ABSTRACT FROM AUTHOR]

Nuclear genome size was determined to investigate the relationships between all 19 species of Araucaria de Jussieu. Species from the two other genera of Araucariaceae, Wollemia and Agathis, were also studied. The genome size of 17 out of the 19 species of Araucaria are reported here for the first time. All Araucariaceae have the same chromosome number 2 n = 26. However, the nuclear DNA contents (2C value) for Araucaria range from 31.3 to 45.4 pg. There is a good correlation between genome size and division in sections, and geographical distribution. The two species from South America have 44.7 and 45.4 pg, the two species from Australia have 35.7 and 44.4 pg and the two species from New Guinea 34.7 and 40.4 pg. All 13 species of New Caledonia and the one from Norfolk Island have a similar, if not identical, amount of nuclear DNA of, on average, 31.9 pg. This corroborates the identical DNA rbcL sequences found for the New Caledonian araucarias. It suggests that the species from New Caledonia diversified more recently and it questions their status as separate species . Compared with this 31.9 pg a strong increase seems to have occurred in the genome size of the 'mainland' araucarias. Genome sizes are evaluated and compared with available taxonomic treatments and extant geographic spreading. The nuclear DNA contents found within the sections are close, making it possible to assign an unknown plant to a section. A difference of 1 pg, which amounts to a difference of 978 Mbp, far exceeds a single character. Nuclear DNA content, as measured by flow cytometry, may conveniently be used to produce systematic data . It is applicable even with young plants or seeds for monitoring the trade in endangered species. [ABSTRACT FROM AUTHOR]

Striga hermonthica, a root hemiparasitic Orobanchaceae, severely constrains grain production in sub-Saharan Africa. Host specificity and geography may play important roles in shaping the population structure of S. hermonthica, with the Rift Valley potentially presenting a significant barrier to dispersal. Genetic diversity was assessed in 12 S. hermonthica populations from locations in Ethiopia. Of these, seven populations were parasitic on sorghum, two each on tef and maize, and one on finger millet. Genetic variation was detected using four amplified fragment length polymorphism (AFLP) primer combinations. After correcting for repeatability, 385 fragments were detected across all primer combinations. The percentage of polymorphic loci was relatively high, ranging from 53.2% to 76.4%. Expected heterozygosity ranged from 0.168 to 0.279. Genetic differentiation between populations was relatively high, and all populations were significantly different from each other . FST values ranged from 0.032 to 0.293 and averaged 0.146. Genetic differences between populations could not be attributed to host specificity. Instead, geography was the main determinant of population structure. There was a correlation between geographic and genetic distance. A significant portion of the genetic variance could be apportioned on either side of the Rift Valley (5%; P = 0:001). Also, a significant geographic barrier was identified in the southern portion of the sampled region. [ABSTRACT FROM AUTHOR]

Aim To use parsimony analysis of endemicity and cladistic analysis of distributions and endemism to evaluate two hypotheses addressing biogeographical relationships among Amazonia, the Caatinga forest enclaves, Pernambuco Centre and the southern Atlantic Forest. Location North-eastern Brazil, South America. Methods To find the most parsimonious areagram we analysed a matrix composed of the presence (1) or absence (0) of 745 taxa (i.e. 293 genera and 452 species of woody plants) within 16 localities belonging to the four large regions addressed in this study. Results One most parsimonious areagram was found and it shows a basal separation between the southern Atlantic Forest and all other regions. This break is followed by a separation between all Caatinga forest enclaves (except Baturité) from a cluster composed of Baturité, the Pernambuco Centre and Amazonia. In this cluster, the most basal separation isolates Baturité from the cluster formed by localities from Amazonia and the Pernambuco Centre. The biogeographical relationships among sites could not be explained by either a random distribution of species among sites or by the geographical distance between sites. Main conclusions We found strong cladistic signal within the raw distribution and phylogenetic data used in our analysis, indicating structured species assemblages in the surveyed localities. They have resulted from the fragmentation of an ancestral biota that was once widely distributed in the region. Our results also support the hypothesis that Atlantic Forest is not a biogeographically natural area, because the Pernambuco Centre is more closely related to Amazonia than to the southern Atlantic Forest. Finally, our data do not support the notion that Caatinga forest enclaves comprise a single biogeographical region, because one Caatinga forest enclave (Baturité) is much more closely related to the cluster formed by Amazonia and the Pernambuco Centre than to other sites. These relationships suggest the occurrence of forest connections between Amazonia and the Atlantic Forests across Caatinga during several periods of the Tertiary and Quaternary. However, palaeoecological data currently available for the Caatinga region are still scarce and do not have either the spatial or temporal resolution required to reconstruct the history of connections among the forests in north-eastern Brazil. [ABSTRACT FROM AUTHOR]

Based on field observations of leaf morphology and variation in chloroplast DNA (cpDNA) in Scandinavia, Norway has been suggested as a suture zone for elm ( Ulmus glabra ) from different glacial refugia. The aim of this paper was to study the geographical concordance between the maternally inherited cpDNA markers (16 populations) and the assumed polygenic and biparentally inherited leaf traits, studied in a field trial (five populations). Two cpDNA haplotypes were detected, but without geographical structure. Leaf traits showed a gradient from typical ssp. montana traits (relatively long, long tapering, absent acute lobes) in western populations to more ssp. glabra -like traits (relatively broad, short tapering, acute lobes present) in eastern and northern populations. The overall geographical concordance between haplotype distribution and leaf traits was limited, probably owing to different inheritance of cpDNA and leaf traits, but the spatial variation in leaf traits and cpDNA in a subset of common populations ( n =5) was compatible with a dual migration of elm to Scandinavia. Both measures suggest a broad suture zone, covering the entire distribution of elm in Norway. The results are discussed in relation to the use of maternally inherited markers, such as cpDNA, in delimiting suture zones. [ABSTRACT FROM AUTHOR]