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Land cover change is a key component of anthropogenic global environmental change, contributing to changes in environmental conditions of habitats. Deforestation is globally the most widespread and anthropogenically driven land cover change leading to conversion from closed forest to open non-forest habitat. This study investigates the relative roles of geographic features, characteristics of species climatic niche and species traits in determining the ability of open-habitat plant species to take advantage of recently opened habitats. We use current occurrence records of 18 herbaceous, predominantly open-habitat species of the genus Acaena (Rosaceae) to determine their prevalence in recently opened habitat. We tested correlation of species prevalence in anthropogenically opened habitat with (i) geographic features of the spatial distribution of open habitat, (ii) characteristics of species climatic niche, and (iii) species traits related to dispersal. While primary open habitat (naturally open) was characterised by cold climates, secondary open habitat (naturally closed but anthropogenically opened) is characterised by warmer and wetter conditions. We found high levels of variation in the species prevalence in secondary open habitat indicating species differences in their ability to colonise newly opened habitat. For the species investigated, geographical features of habitat and climatic niche factors showed generally stronger relationships with species prevalence in secondary open habitat than functional traits. Therefore, for small herbaceous species, geographical features of habitat and environmental factors appear to be more important than species functional traits for facilitating expansion into secondary open habitats. Our results suggested that the land cover change might have triggered the shifts of factors controlling open-habitat plant distributions from the competition with forest trees to current environmental constraints. [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]

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]

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]

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]

Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, was responsible for the Irish potato famine of the 1840s. Initial disease outbreaks occurred in the US in 1843, two years prior to European outbreaks. We examined the evolutionary relationships and source of the 19th-century outbreaks using herbarium specimens of P. infestans from historic (1846–1970) and more recent isolates (1992–2014) of the pathogen. The same unique SSR multilocus genotype, named here as FAM-1, caused widespread outbreaks in both US and Europe. The FAM-1 lineage shared allelic diversity and grouped with the oldest specimens collected in Colombia and Central America. The FAM-1 lineage of P. infestans formed a genetic group that was distinct from more recent aggressive lineages found in the US. The US-1 lineage formed a second, mid-20th century group. Recent modern US lineages and the oldest Mexican lineages formed a genetic group with recent Mexican lineages, suggesting a Mexican origin of recent US lineages. A survey of mitochondrial haplotypes in a larger set of global herbarium specimens documented the more frequent occurrence of the HERB-1 (type Ia) mitochondrial haplotype in archival collections from 1866–75 and 1906–1915 and the rise of the Ib mitochondrial lineage (US-1) between 1946–1955. The FAM-1 SSR lineage survived for almost 100 years in the US, was geographically widespread, and was displaced first in the mid-20th century by the US-1 lineage and then by distinct new aggressive lineages that migrated from Mexico. [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]

Postglacial climate changes alter geographical distributions and diversity of species. Such ongoing changes often force species to migrate along the latitude/altitude. Altitudinal gradients represent assemblage of environmental, especially climatic, variable factors that influence the plant distributions. Global warming that triggered upward migrations has therefore impacted the alpine plants on an island. In this study, we examined the genetic structure of Juniperus morrisonicola, a dominant alpine species in Taiwan, and inferred historical, demographic dynamics based on multilocus analyses. Lower levels of genetic diversity in north indicated that populations at higher latitudes were vulnerable to climate change, possibly related to historical alpine glaciers. Neither organellar DNA nor nuclear genes displayed geographical subdivisions, indicating that populations were likely interconnected before migrating upward to isolated mountain peaks, providing low possibilities of seed/pollen dispersal across mountain ranges. Bayesian skyline plots suggested steady population growth of J. morrisonicola followed by recent demographic contraction. In contrast, most lower-elevation plants experienced recent demographic expansion as a result of global warming. The endemic alpine conifer may have experienced dramatic climate changes over the alternation of glacial and interglacial periods, as indicated by a trend showing decreasing genetic diversity with the altitudinal gradient, plus a fact of upward migration. [ABSTRACT FROM AUTHOR]

Miscanthus is a leading bioenergy candidate for biofuels, and it thus becomes essential to characterize the desire natural Miscanthus germplasm accessions with high biomass saccharification. In this study, total 171 natural Miscanthus accessions were geographically mapped using public database. According to the equation [P(H/L| East) = P(H/L∩East)/P(East)], the probability (P) parameters were calculated on relationships between geographical distributions of Miscanthus accessions in the East of China, and related factors with high(H) or low(L) values including biomass saccahrification under 1% NaOH and 1% H2SO4 pretreatments, lignocellulose features and climate conditions. Based on the maximum P value, a golden cutting line was generated from 42°25’ N, 108°22’ E to 22°58’ N, 116°28’ E on the original locations of Miscanthus accessions with high P(H|East) values (0.800–0.813), indicating that more than 90% Miscanthus accessions were originally located in the East with high biomass saccharification. Furthermore, the averaged insolation showed high P (H|East) and P(East|H) values at 0.782 and 0.754, whereas other climate factors had low P(East|H) values, suggesting that the averaged insolation is unique factor on Miscanthus distributions for biomass saccharification. In terms of cell wall compositions and wall polymer features, both hemicelluloses level and cellulose crystallinity (CrI) of Miscanthus accessions exhibited relative high P values, suggesting that they should be the major factors accounting for geographic distributions of Miscanthus accessions with high biomass digestibility. [ABSTRACT FROM AUTHOR]

Growing evidence shows that increasing global temperature causes population declines and latitudinal shifts in geographical distribution for plants living near their thermal limits. Yet, even populations living well within established thermal limits of a species may suffer as the frequency and intensity of warming events increase with climate change. Adaptive response to this stress at the population level depends on the presence of genetic variation in thermal tolerance in the populations in question, yet few data exist to evaluate this. In this study, we examined the immediate effects of a moderate warming event of 4.5°C lasting 5 weeks and the legacy effects after a 5 week recovery on different genotypes of the marine plant Zostera marina (eelgrass). We conducted the experiment in Bodega Bay, CA USA, where average summer water temperatures are 14–15°C, but extended warming periods of 17–18°C occur episodically. Experimental warming increased shoot production by 14% compared to controls held at ambient temperature. However, after returning temperature to ambient levels, we found strongly negative, delayed effects of warming on production: shoot production declined by 27% and total biomass decreased by 50% relative to individuals that had not been warmed. While all genotypes’ production decreased in the recovery phase, genotypes that grew the most rapidly under benign thermal conditions (control) were the most susceptible to the detrimental effects of warming. This suggests a potential tradeoff in relative performance at normal vs. elevated temperatures. Modest short-term increases in water temperature have potentially prolonged negative effects within the species’ thermal envelope, but genetic variation within these populations may allow for population persistence and adaptation. Further, intraspecific variation in phenology can result in maintenance of population diversity and lead to enhanced production in diverse stands given sufficient frequency of warming or other stress events. [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]

Forest tree species of temperate and boreal regions have undergone a long history of demographic changes and evolutionary adaptations. The main objective of this study was to detect signals of selection in Norway spruce (Picea abies [L.] Karst), at different sampling-scales and to investigate, accounting for population structure, the effect of environment on species genetic diversity. A total of 384 single nucleotide polymorphisms (SNPs) representing 290 genes were genotyped at two geographic scales: across 12 populations distributed along two altitudinal-transects in the Alps (micro-geographic scale), and across 27 populations belonging to the range of Norway spruce in central and south-east Europe (macro-geographic scale). At the macrogeographic scale, principal component analysis combined with Bayesian clustering revealed three major clusters, corresponding to the main areas of southern spruce occurrence, i.e. the Alps, Carpathians, and Hercynia. The populations along the altitudinal transects were not differentiated. To assess the role of selection in structuring genetic variation, we applied a Bayesian and coalescent-based FST-outlier method and tested for correlations between allele frequencies and climatic variables using regression analyses. At the macro-geographic scale, the FST-outlier methods detected together 11 FST-outliers. Six outliers were detected when the same analyses were carried out taking into account the genetic structure. Regression analyses with population structure correction resulted in the identification of two (micro-geographic scale) and 38 SNPs (macro-geographic scale) significantly correlated with temperature and/or precipitation. Six of these loci overlapped with FST-outliers, among them two loci encoding an enzyme involved in riboflavin biosynthesis and a sucrose synthase. The results of this study indicate a strong relationship between genetic and environmental variation at both geographic scales. It also suggests that an integrative approach combining different outlier detection methods and population sampling at different geographic scales is useful to identify loci potentially involved in adaptation. [ABSTRACT FROM AUTHOR]

Most species distribution models assume a close link between climatic conditions and species distributions. Yet, we know little about the link between species' geographical distributions and the sensitivity of performance to local environmental factors. We studied the performance of three bryophyte species transplanted at south- and north-facing slopes in a boreal forest landscape in Sweden. At the same sites, we measured both air and ground temperature. We hypothesized that the two southerly distributed species Eurhynchium angustirete and Herzogiella seligeri perform better on south-facing slopes and in warm conditions, and that the northerly distributed species Barbilophozia lycopodioides perform better on north-facing slopes and in relatively cool conditions. The northern, but not the two southern species, showed the predicted relationship with slope aspect. However, the performance of one of the two southern species was still enhanced by warm temperatures. An important reason for the inconsistent results can be that microclimatic gradients across landscapes are complex and influenced by many climate-forcing factors. Therefore, comparing only north- and south-facing slopes might not capture the complexity of microclimatic gradients. Population growth rates and potential distributions are the integrated results of all vital rates. Still, the study of selected vital rates constitutes an important first step to understand the relationship between population growth rates and geographical distributions and is essential to better predict how climate change influences species distributions. [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]

Patterns that resemble strongly skewed size distributions are frequently observed in ecology. A typical example represents tree size distributions of stem diameters. Empirical tests of ecological theories predicting their parameters have been conducted, but the results are difficult to interpret because the statistical methods that are applied to fit such decaying size distributions vary. In addition, binning of field data as well as measurement errors might potentially bias parameter estimates. Here, we compare three different methods for parameter estimation – the common maximum likelihood estimation (MLE) and two modified types of MLE correcting for binning of observations or random measurement errors. We test whether three typical frequency distributions, namely the power-law, negative exponential and Weibull distribution can be precisely identified, and how parameter estimates are biased when observations are additionally either binned or contain measurement error. We show that uncorrected MLE already loses the ability to discern functional form and parameters at relatively small levels of uncertainties. The modified MLE methods that consider such uncertainties (either binning or measurement error) are comparatively much more robust. We conclude that it is important to reduce binning of observations, if possible, and to quantify observation accuracy in empirical studies for fitting strongly skewed size distributions. In general, modified MLE methods that correct binning or measurement errors can be applied to ensure reliable results. [ABSTRACT FROM AUTHOR]

Aims: Platycladus orientalis (Cupressaceae) is an old-growth tree species which distributed in the imperial parks and ancient temples in Beijing, China. We aim to (1) examine the genetic diversity and reproductive traits of old-growth and young populations of P. orientalis to ascertain whether the older populations contain a higher genetic diversity, more private alleles and a higher reproductive output compared with younger populations; (2) determine the relationships between the age of the population and the genetic diversity and reproductive traits; and (3) determine whether the imperial parks and ancient temples played an important role in maintaining the reproductive capacity and genetic diversity of Platycladus orientalis. Methods: Samples from seven young (younger than 100 yrs.) and nine old-growth (older than 300 yrs.) artificial populations were collected. For comparison, three young and two old-growth natural populations were also sampled. Nine microsatellite loci were used to analyze genetic diversity parameters. These parameters were calculated using FSTAT version 2.9.3 and GenAlex v 6.41. Important Findings: The old-growth artificial populations of P. orientalis have significantly higher genetic diversity than younger artificial populations and similar levels to those in extant natural populations. The imperial parks and ancient temples, which have protected these old-growth trees for centuries, have played an important role in maintaining the genetic diversity and reproductive capacity of this tree species. [ABSTRACT FROM AUTHOR]

A proper phytogeographic affiliation of Antarctic lichen species has become feasible using molecular phylogeographic methods. Caloplaca citrina is a heterogeneous taxon including several species which occurs in polar regions and is common in Antarctica. Collections of C. citrina from the Antarctic were revised using morphological, anatomical and molecular characters (ITS). They were found to belong to two species: Caloplaca darbishirei (C.W. Dodge & G.E. Baker) Cretz. and C. soropelta (E.S. Hansen, Poelt & Søchting) Søchting. The molecular phylogeny showed them to be sister species, but well separated. Morphological and chemical characters, ecology and distribution of the species are discussed. C. darbishirei is the most common species in the Antarctic, and it is so far known only from Antarctica and Southern South America. C. soropelta, reported here as new to South America, is a bipolar species with all close relatives in the Southern Hemisphere; it is therefore most likely that the species colonized the Arctic from the south. C. citrina s. str. is not confirmed to occur in Antarctica. The study emphasizes the suitability of genotyping for understanding the taxonomy and phylogeography of bipolar lichens. [ABSTRACT FROM AUTHOR]

Iris series Hexagonae is a small, monophyletic complex of five species and associated hybrid populations, popularly known as the "Louisiana irises." The Hexagonae alliance of Iris has been recognized as a textbook case of introgressive hybridization on the basis of numerous studies in Louisiana. In light of field observations of phenotypic heterogeneity among Florida populations, we investigated genetic variation within and among 37 populations of Iris series Hexagonae from Florida, seven from Louisiana, and one from Texas with 19 microsatellite loci. We wished to test the hypothesis that the Lake Wales Ridge and Polk Uplands of Florida, which remained above sea level maxima during the early Pleistocene, might be the sites of origin for all extant iris populations in Florida and possibly the series Hexagonae in its entirety. We also hypothesized that phenotypic heterogeneity observed in Florida iris would be reflected in patterns of allelic diversity. Finally, we wished to seek evidence of Native American influence on the present distribution of iris in Florida. Most populations display clonality, including three populations that are predominantly one or two clones. Levels of gene diversity are high and the populations are highly differentiated, although 19 exhibit significant homozygote excess. The majority of genetic variation occurs within populations. Genetic distance resolves three large clusters. One unites the southernmost populations with those from north-central Gulf coastal Florida. A second encompasses southwest Gulf coastal populations. If three compound repeat loci are dropped from the data, these two clusters are united. The third group joins populations derived from the Central Highlands of peninsular Florida, which are genetically isolated from all other peninsular Florida populations, with populations of Iris fulva, Iris brevicaulis, Iris giganticaerulea, and Iris hexagona s.s., supporting recognition of the latter two as distinct species. Model-based Bayesian clustering supports high population differentiation (K = 22) and isolation of Central Highlands populations, and it resolves the terminal clusters of the genetic distance topology. Isolation by distance is significant yet weak because of genetic distance relationships that contradict biogeographic expectations. We propose that the Lake Wales Ridge and Polk Uplands, which constituted the Wicomico shoreline during an early Pleistocene interglacial inundation, functioned as refugia for series Hexagonae. Moreover , we suggest that Florida iris populations occupying high, dry habitats close to the Central Highlands ridges represent relicts of once-larger populations that adapted to the more xeric condition during the last glacial maximum. These populations have a distinctive floral phenotype and are related to species of Hexagonae iris outside of peninsular Florida. Excessively clonal populations may have been deliberately cultivated by Native Americans, which may also have influenced the connection between southern and north-central Florida populations, but there is insufficient evidence to validate this hypothesis. Many populations test positively for recent bottlenecks, which we attribute primarily to founder effects, given the low migration rates of the species and the high degree of population differentiation as well as the Holocene geological history of the Florida peninsula. We present evidence of peripatric divergence in series Hexagonae iris and suggest that this may function as a significant generator of species diversity in the group. [ABSTRACT FROM AUTHOR]

The relationship between the proportion of species with an entire leaf margin (pE) and mean annual temperature (MAT) is one of the most powerful tools for estimating palaeotemperatures. However, phylogenetic and phytogeographic constraints on this relationship have remained unexplored. Here we investigate the pE-MAT relationship for modern floristic assemblages from southern South American forests, assess its conformity to other models and test for the existence of historical constraints on pE-MAT models. South America. We used samples from 30 sites located in Chile between 32° and 44° S to test for a pE-MAT relationship and compared it with four regional models. We assessed the reliability of these models for predicting MAT from instrumental records in eight modern temperate-forest localities in Chile. Additionally, palaeotemperatures for Cenozoic fossil floras were estimated. To assess historical constraints in pE, we measured the phylogenetic signal in leaf margin type and the association between leaf margin and phytogeographic affiliation, defined by the distribution of genera. We found a significant pE-MAT relationship for Chilean forest species that differed from Australia and Northern Hemisphere models, but not from tropical South America (TSA). Temperatures for southern South American localities predicted from the new regional model - combining Chilean and TSA datasets - were more accurate than those from previous models. We also showed that leaf margin type has a strong phylogenetic signal, which was further confirmed by the highly significant effect of phytogeographic element on leaf margin type. Differences between the Chilean and other regional models are explained by historical legacy, as Chilean leaf margin types are strongly affected by phylogenetic closeness and phytogeographic elements. We highlight that leaf margin analyses should be conducted within the context of a flora with a shared history. Thus, we propose a new model for South America to estimate palaeotemperatures for regional fossil floras. [ABSTRACT FROM AUTHOR]

Abstract: Little is known about the variation in demographics, flower number, fruit set, and summer dormancy in Allium species native to the Intermountain West region of the United States. The purpose of this study was to investigate demographic patterns, summer dormancy traits, and variation in reproductive characteristics among habitats. Three populations of each of three species, Allium acuminatum, A. brandegei, and A. passeyi, were studied along an altitudinal gradient in northern Utah, USA, from 2004 to 2006. Demographic data were collected from individuals in permanent plots established in each population. Individual flowering plants were periodically monitored and used to calculate reproductive characteristics. Leaf area measurements throughout the 2005 growing season and soil temperature sensors were used to assess the relationship between habitat and dormancy characteristics. Populations of the widely distributed species, A. acuminatum and A. brandegei, were dominated by individuals in seedling and flowering stages while the restricted A. passeyi had populations containing a majority of individuals in the post-seedling, but non-flowering stage-class. There was a strong directional trend in A. acuminatum reproductive traits, with flower number and fruit set decreasing with increasing elevation. The mid-elevation A. brandegei populations were reproductively more successful than the high and low-elevation populations. The high-elevation A. passeyi population had more flowers per plant and higher fruit set in comparison to the lower elevation populations. The onset of summer dormancy as indicated by the timing of leaf senescence, was associated with high soil temperatures specific to each species. In general, the timing of leaf senescence was later in higher elevation populations in all species. A smaller proportion of non-flowering individuals in A. acuminatum and A. brandegei may indicate a high seedling mortality rate or a shorter juvenile phase in comparison to A. passeyi. The A. passeyi populations exhibit demographic characteristics of rare taxa; low seed production and low seedling recruitment. The high number of non-flowering plants in A. passeyi likely includes many reproductively mature individuals which are influenced by the unique habitat and environment of this species. Temperature is likely the key environmental cue inducing summer dormancy in all three species. [Copyright &y& Elsevier]

Plant distributions are in part determined by environmental heterogeneity on both large (landscape) and small (several meters) spatial scales. Plant populations can respond to environmental heterogeneity via genetic differentiation between large distinct patches, and via phenotypic plasticity in response to heterogeneity occurring at small scales relative to dispersal distance. As a result, the level of environmental heterogeneity experienced across generations, as determined by seed dispersal distance, may itself be under selection. Selection could act to increase or decrease seed dispersal distance, depending on patterns of heterogeneity in environmental quality with distance from a maternal home site. Serpentine soils, which impose harsh and variable abiotic stress on non-adapted plants, have been partially invaded by Erodiwn cicutariuni in northern California, USA. Using nearby grassland sites characterized as either serpentine or non-serpentine, we collected seeds from dense patches of E. cicutariuni on both soil types in spring 2004 and subsequently dispersed those seeds to one of four distances from their maternal home site (0, 0.5, 1, or 10 m). We examined distance-dependent patterns of variation in offspring lifetime fitness, conspecific density, soil availability, soil water content, and aboveground grass and forb biomass. ANOVA revealed a distinct fitness peak when seeds were dispersed 0.5 m from their maternal home site on serpentine patches. In non-serpentine patches, fitness was reduced only for seeds placed back into the maternal home site. Conspecific density was uniformly high within 1 m of a maternal home site on both soils, whereas soil water content and grass biomass were significantly heterogeneous among dispersal distances only on serpentine soils. Structural equation modeling and multigroup analysis revealed significantly stronger direct and indirect effects linking abiotic and biotic variation to offspring performance on serpentine soils than on non- serpentine soils, indicating the potential for soil-specific selection on seed dispersal distance in this invasive species. [ABSTRACT FROM AUTHOR]

We developed multiple a priori hypotheses to link the observed spatial patterns with colonisation processes in the high alpine cushion plant, Azorella madreporica. We conducted this study in the Molina River basin (33°20′ S, 70°16′ W, 3600 m a.s.l.), in the Andes of central Chile, approximately 50 km east of Santiago. We mapped and measured size (as a surrogate for age) of individual cushions in two populations and used a standard spatial analytical tool (semivariograms) to test our alternative a priori hypotheses related to colonisation mode of the cushion species. In both populations, the size distribution of A. madreporica reflected a negative exponential or inverse-J pattern, typical of uneven-aged populations, where most of the cushions belonged to relatively smaller size classes, in effect, a regular success in the establishment of seedlings, where all size classes of cushions were represented in the population. The results were site-specific, where best-fit semivariograms for spatial cushion's size distribution suggested a gradual colonisation in one population and an episodic colonisation in the other population. Microsite distribution proved to be homogeneous at both sites. Thus, the study of the spatial explicit size-age population distribution of an alpine species provides valuable information about the frequency, magnitude and site variation of the reproductive pulses in these harsh environments. [ABSTRACT FROM AUTHOR]

We investigated genetic variation within and among 11 populations of Iris hexagona at its southern limits in the Florida peninsula by using 19 microsatellite loci. All of the populations contain varying numbers of identical multilocus genotypes, indicative of clonal reproduction. Two population samples consist largely of one clonal lineage and two clonal lineages: the first from the Caloosahatchee drainage west of Lake Okeechobee and the other from the Big Cypress Swamp. The populations are predominantly outcrossing, with high levels of heterozygosity, and show a highly significant pattern of isolation by distance that fits a modified stepping-stone model. This pattern breaks down at the local level, however, where metapopulation dynamics or asymmetrical gene flow may exert a stronger effect on patterns of genetic diversity. Though the majority of genetic variation is within populations, 20% occurs between populations. Genetic distance resolves five clusters: four in the Caloosahatchee Valley and one in the Big Cypress Swamp. However, the populations are differentiated strongly enough that frequency-based genetic structure analysis resolves seven effective populations. Assignment tests identify the northernmost population as a likely ancestral point of origin for the others. All of the populations exhibit evidence of a recent bottleneck, which we attribute to founder effects, given the low migration rate of the species and the high degree of population differentiation, as well as the Holocene geological history of the Florida peninsula.We hypothesize that the two predominantly clonal populations may be artifacts of deliberate cultivation by humans. [ABSTRACT FROM AUTHOR]

Geographically peripheral populations of widespread species are often the focus of conservation because they are locally rare within political jurisdictions. Yet the ecology and genetics of these populations are rarely evaluated in a broader geographic context. Most expectations concerning the ecology and evolution of peripheral populations derive from the abundant-center model, which predicts that peripheral populations should be less frequent, smaller, less dense, and have a lower reproductive rate than central populations. We tested these predictions and in doing so evaluated the conservation value of peripheral populations for the clonal shrub Vaccinium stamineum L. (Ericaceae, deerberry), which is listed as threatened in Canada. Based on 51 populations sampled from the center to the northern range limits over 2 years, population frequency and size declined toward the range limit, but ramet density increased. Sexual reproductive output varied widely among populations and between years, with many populations producing very few seeds, but did not decline toward range margins. In fact seed mass increased steadily toward range limit, and this was associated with faster germination and seedling growth, which may be adaptive in seasonal northern environments. Our results did not support the prediction that clonal reproduction is more prevalent in peripheral populations or that it contributed antagonistically to the wide variation in seed production. Peripheral populations of V. stamineum are as productive as central populations and may be locally adapted to northern environments. This emphasizes the importance of a broad geographical perspective for evaluating the ecology, evolution, and conservation of peripheral populations. [ABSTRACT FROM AUTHOR]

Pogonia japonica (Orchidaceae) is a clonal plant forming numerous adventitious shoots on long perennial roots. Seeds remained dormant for 3 years or more and rarely germinated. Populations consisted of ramets of different ages. Each ramet was a partial shoot growing vertically and monopodially before changing to sympodial growth after the first flowering. Annual growth consisted of two internodes making it easy to determine the shoot age. Three to 12 ramets were connected by a common root system. This might provide rapid development of ramets. In favorable habitats, vigorous ramets started flowering in the second or third year, and flowering lasted for another 3–4 years. In unfavorable habitats, preflowering shoot development took 3–5 years, or it died before or just after the first flowering. Ramets remained alive but senescent for 1–2 years after the last flowering. Disconnection of 2–4-year-old shoots was a normal process of vegetative reproduction. Some isolated mature shoots stayed dormant for 1–2 years. Young shoots disconnected within the first year usually died. Vegetative mature shoots predominated in the Russian populations, whereas young ramets were more numerous in the Japanese populations. The proportion of flowering to vegetative shoots averaged 15%, but reached as high as 55% in one Japanese population. Fruiting was high (80%) in Russian populations, but in some Japanese populations it dropped to zero after all fruits were damaged by insects. Differences in plant size and population structure reflected differences in ecological conditions more than geographic difference. [ABSTRACT FROM AUTHOR]

Although the effects of deterministic factors on population viability often are more important than stochasticity, few researchers have dealt with the effect of deterministic habitat changes on plant population demography. We assessed population viability for the perennial herb Primula veris L. and identified targets for management based on demographic data from five different habitat types representing different degrees of canopy closure. We conducted replicate studies at the border of the distribution area and in more central parts. Demographic patterns were similar between the two regions. Most study populations had a positive population growth, and only populations in late phases of forest succession showed consistently negative trends. The populations of open habitats had high seedling recruitment, and the populations of early and middle forest succession had high seed production. The importance of survival for population growth rate increased with increasing habitat closure, whereas the importance of growth and reproduction decreased. Results of the elasticity analysis suggested that the best method to manage decreasing late-successional populations is to increase survival of the largest individuals. The life-table response experiment (LTRE) analysis, however, showed that survival of the largest individuals contributed little to differences in population growth rates of different habitats, whereas seed production and growth of small individuals were more important. Moreover, direct perturbation of the performance of the largest stages showed that late-successional populations would not attain positive population growth even if the largest stages had no mortality at all. We conclude that restoration of recruitment is the only possibility for positive population growth in late-successional populations of P. veris , although the elasticities of recruitment transitions are low. Our results also suggest that retrospective demographic methods such as LTRE constitute an important and necessary complement to prospective methods such as elasticities in identifying management targets. [ABSTRACT FROM AUTHOR]

Six native Rhododendron species grow in the degraded, fire-prone landscape of Hong Kong: R. simsii and R. farrerae are common and widespread, R. moulmainense is relatively restricted, and R. championiae, R. hongkongense, and R. simiarum are rare. For all species except the rare R. simiarum, there was direct or indirect evidence of regrowth after fire, but only the two smallest and commonest species grow in sites which are frequently burned. Both flowered within 18 months of a fire. Most populations of all species, except R. simiarum, had a deficiency of individuals in the smaller basal circumference classes. Seedlings were found only in three out of four plots of R. simiarum, and one of R. farrerae. A few seedlings of the other rare species were seen in open, litter-free microsites outside the study plots, but no seedlings of the most common species, R. simsii, were seen anywhere. In logistic regression models, one or more measures of plant size were significant positive predictors of flowering at least once in the three year study period for all species, while percentage cover by surrounding vegetation had a significant negative impact on all except R. simsii and R. farrerae, for which no populations are strongly-shaded. Although the absence of current recruitment is not necessarily a cause for concern in long-lived species that can resprout after fire, we recommend that active vegetation management should be tried to enhance the survival and reproduction of R. moulmainense, R. championiae and R. hongkongense, and that new populations of these species and R. simiarum should be created. [ABSTRACT FROM AUTHOR]

We analysed the distribution of native and alien plant species across 20 ecogeographic zones of northwestern Kenya. The source pool for the majority of aliens was Europe and America. Thus, the source pool has a biogeographic bias which explains the low proportion of aliens in the tropics: most species in the European or American source pool are not well adapted to tropical conditions. As expected, native and alien plant species showed an area effect. Correcting for this area effect, species rich zones showed a higher proportion of alien plant species in their flora. At the analysed scale, species richness of native plant communities does not increase the resistance to invasions and alien plant species invade diversity hotspots. Compared to the other ecogeographic zone, the urban area around Nairobi showed an increased richness in alien and native plant species. This is very similar to findings in Europe, although the history of urbanisation is much shorter in Kenya. The species turnover between zones (β-diversity) shows a similar pattern in native and alien plant species. Within a very short time scale the alien plant species mapped the biogeographic patterns of natives, although the geography of human activities influences the propagule pressure. [ABSTRACT FROM AUTHOR]

The article presents E. C. Pielou's devised valuable index of non-randomness of the distribution of a plant population which intends to test for a departure of a plant distribution from randomness and serves as a measure of the amount of non-randomness in the distribution in the case of a non-random distribution. Pielou has only cited the sampling errors of the point-to-plant distances. It is noted that the devised index is computed from the information supplied by a sample of point-to-nearest-plant distances as well as the second sample of quadrat counts.

It appears from large scale sampling and from detailed mapping that the distribution of Enchytraeids over areas of the order of 100 sq. m and of 0.5 sq. m was non-random (under-dispersed). The range of absolute numbers was smaller in the small that in the large areas while it was almost identical when expressed in standard measure. Small scale density gradients are superimposed upon large scale ones. [ABSTRACT FROM AUTHOR]

Geographic variation and interspecific differentiation in body size (body length) were analyzed for 15 species of the carabid subgenus Ohomopterus (genus Carabus; Coleoptera, Carabidae) in Japan. Local species assemblages of this subgenus consist of up to 5 species of different size classes. These beetles exhibited sexual dimorphism in body size where females are larger than males, except Carabus uenoi, in which the male and female sizes were equivalent, possibly because of theexaggerated male genitalia. In 9 of 15 species, there was a positivecorrelation between mean body size and annual mean temperature of habitat, representing the converse of Bergmann's rule. However, in somecases this correlation does not hold over the range of a species because of regional differences. When allopatric and sympatric populations were compared, allopatric populations of Carabus albrechti and C. japonicus had larger bodies than sympatric populations. These intraspecific differences may have resulted from character displacement. In each local assemblage with 2 or more species, there was little interspecific overlap of body size, although the body size ratio between two species with adjacent body sizes seldom showed strict constancy. The mean size ratio between 2 adjacent species in an assemblage was reduced with the number of species, whereas the size ratio of the largest to smallest species in an assemblage increased with the number of species (i.e., the expansion of body size range). These results indicate that the body size of Ohomopterus species may have evolved in response to both climatic conditions and interspecific interactions. Because each species or species group represents the same size class overthe distribution range and similar-sized species are parapatric or allopatric, the interspecific segregation in body size in local assemblages may have resulted mainly from a size assortment process during colonization. [ABSTRACT FROM AUTHOR]

In Canada, Viola praemorsa ssp. praemorsa is restricted to Quercus garryana stands and grass-dominated meadows on southeastern Vancouver Island and Saltspring Island. Eight sites have been confirmed in recent years but the status of plants at five other sites remains uncertain. It is likely that the violet has been extirpated in at least one of these sites. These Canadian sites represent the northern range limits of Viola praemorsa ssp. praemorsa at the species and subspecies levels. Threats to existing populations vary in intensity. Although most populations are protected to a certain extent from direct habitat destruction, introduced species pose a serious potential threat to the continued existence of most populations. Unfortunately, managing sites for V. praemorsa ssp. praemorsa is difficult because so little information is available regarding the general biology of this species. [ABSTRACT FROM AUTHOR]