Spatial and temporal variation of consanguinity in Italy

Genetic structure of Italian population is described as regards the level of inbreeding measured through the frequency of consanguineous marriages during a long period of time in different geographical areas. Analyses of spatial and temporal variation of the different types of marriages between close biological relatives allow us to point out the major factors responsible for the availability of cousins to marry within a specific area: population size, fertility, mortality and migration rates and, in general the demographic structure, changing over time and greatly affected by variation in the socio-economic structure. A deepened analysis, within each consanguinity degree, of the various pedigrees differing in the sex of ancestors, give information on the type of migration (patrilocal or matrilocal) occurred in various parts of Italy, as probable consequence of differential type of economy (for instance: pastoral or agricultural in Sardinia). Moreover, a cultural factor of varying intensity could be recognized in the greater observed frequency of marriages in which the nearest ancestors are females, interpreted as a tendency to maintain family ties by mothers of consanguineous mates.     

The role of spatial and ontogenetic morphological variation in the expansion of the geographic range of the tropical brown alga, Turbinaria ornata

Like many reefs worldwide, reefs in French Polynesia are experiencing a shift from coral-dominated to algal-dominated systems. The macroalga Turbinaria ornata comprises the majority of the increasing algal biomass on the barrier reefs surrounding these islands, and its distribution is increasing throughout this region. Aspects of the ecomorphology of Turbinaria make it ideally suited to thrive under the physical conditions found across barrier reefs throughout French Polynesia. Spatial morphological variation allows Turbinaria to produce morphotypes that are suited either to the calm, unidirectional, slowly flowing water in the backreef or to the high-energy wave-driven flow of the forereef. Backreef plants are flexible and produce airbladders that make them buoyant, whereas forereef plants are not buoyant, but strong and stiff. Production of bladders and resulting buoyancy has been found to be a phenotypically plastic trait in response to movement of water and confers advantages to backreef plants and plays an important role in dispersal. Ontogenetic variation of buoyancy, material properties, and reproductive capacity is part of a dispersal strategy whereby fertile, buoyant fronds drift between oceanic islands and form new populations, thereby contributing to the recent expansion of range of T. ornata across French Polynesia.     

Spatial and temporal variation in flight morphology in the butterfly Melitaea cinxia (Lepidoptera: Nymphalidae)

Some studies on insects have found a relationship between habitat structure and investment in dispersal-related traits. In this study we compared the morphology of the butterfly Melitaea cinxia from five sites on the large Baltic island Öland that differed markedly in degree of fragmentation and size. Both wild-caught adults and individuals reared in a split-plot design were compared. We found significant site differences in size-adjusted thorax mass and total body mass. Male thorax mass was on average larger among the sites with the highest degree of habitat fragmentation. However, due to significant sex–site interactions, males and females may have adapted differently to the habitat fragmentation. Using museum specimens, we also analysed changes in morphology, finding an increase in size (measured as head and thorax width) over time. Thorax width appears to have increased among females and decreased among males. Possible explanations include increasing fragmentation of the landscape and changes in population density.  © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77 , 445–453.     

Spatial and temporal variation in lightning ignitions in Sweden

Abstract. Analysis of fire statistics revealed that there are steep gradients in the distribution of lightning-caused fire ignitions in Sweden. The highest ignition density was found in the southeastern provinces of Kalmar and Östergötland, ca. 0.23/10 000 ha/yr. From there, densities generally declined both to the north and to the west, with a density averaging ca. 0.05 in the six northernmost provinces, and an equally low density in the southwestern province of Halland. For both northern and southern Sweden, lightning ignitions peaked in early July, but in the south the season for ignitions started 2–3 weeks earlier and ended 2–3 weeks later. The geographical gradients in lightning ignition density correspond to the average precipitation during summer. The patterns of lightning ignition densities may also indicate gradients in natural fire frequencies. This hypothesis is supported by the distribution of certain fire-adapted plant species.     

Immunomodulatory activity of brown algae Turbinaria ornata derived sulfated polysaccharide on LPS induced systemic inflammation

BackgroundInflammation and oxidative stress are common pathologies in a wide range of chronic diseases. Polysaccharides are known to exhibit antioxidant and anti-inflammatory potential and are suggested to possess immunomodulatory potential.PurposeHerein, the immunomodulatory activity of a sulfated polysaccharide (PS) separated from a brown marine algae Turbinaria ornata is studied in LPS instigated systemic inflammation in experimental rats.Study design and methodsMale SD rats are pretreated with different doses of PS (2.5, 5, 10 mg/kg bw) for a week followed by inducing systemic inflammation using LPS (10 mg/kg i.p.). Blood withdrawn after 8 h of LPS injection is subjected to hematological analysis (WBC, HCT, and PLT). After 24 h of LPS induction, cardiac tissue was isolated and subjected to biochemical, molecular, and histopathological analysis. Effect of PS pre-treatment (2.5, 5, 10 mg/kg bw) was checked by assessing serum parameters (AST, CK-MB, and γGT), antioxidant markers (LPO, GSH, SOD, Grx) and inflammatory markers (IL1β, IL6, IL10, NFκB), followed by analyzing the iNOS, PI3k and Akt to identify the probable mode of action.ResultsElevated levels of AST, CK-MB, and γGT in serum were significantly reduced on PS pretreatment. LPS significantly raised the LPO and Grx levels in heart tissue whereas, PS pre-treatment significantly reduced LPO and Grx levels. GSH and SOD levels were reduced upon LPS induction and were brought to near normal by HD of PS. PS also reduced the mRNA levels of IL6, Trx, and increased IL10 levels in the heart tissue substantiating its anti-inflammatory and antioxidant potency. Further, IL1β, NFκB, iNOS, and pPI3k/pAkt expressions were significantly modulated by PS in the cardiac tissue substantiating the immunomodulatory effect. A trend of improvement in the inflammatory pathology was also observed in the heart tissue compared to LPS control, as confirmed by histopathology analysis.ConclusionAltogether, this study concludes the immunomodulatory potential of PS from the marine macroalgae Turbinaria ornata significantly and prevents LPS induced systemic inflammation in the cardiac tissue presumably influenced by the glucopyranose and fucopyranose subunits in the polysaccharide.     

Natural settlement dynamics of a young population of Turbinaria ornata and phenological comparisons with older populations

Our study was done during 16 months on two sites at Moruroa to (i) compare Moruroan populations (young) with Tahitian populations (old) of Turbinaria ornata and (ii) follow the natural dynamic of a young population at Moruroa. Moruroan and Tahitian populations have maximal density and maximal reproductive characteristics during the cool and hot seasons, respectively. Recruits are present throughout the year at all sites. Within the reference field site, individuals were initially distributed regularly and then became clumped through time, recruits appeared around adults. Recruits mortality followed a similar pattern, whereas mortality of adults and juveniles was even throughout the monitoring period. Populations initially had similar proportions of recruits, juveniles and adults (28, 40 and 32%, respectively), but at the end, recruits represent 92% of the population. A linear relationship between the number of individuals present within the station and the colonized substrate area was determined (R² = 0.96), suggesting a limiting effect of the substrate against the settlement of T. ornata with time. Moreover, the growth of recruits in the close vicinity of adults was arrested in the young populations: recruitment may therefore, significantly buffer high rates of adult mortality. It may contribute to the invasion and, more interesting to the persistence of T. ornata in new colonized area.     

Spatial and temporal variation in the morphology (and thus, predicted impact) of an invasive species in Australia

The impact of an invasive species is unlikely to be uniform in space or time, due to variation in key traits of the invader (e.g. morphology, physiology, behaviour) as well as in resilience of the local ecosystem. The weak phylogeographic structure typical of an invasive population suggests that much of the variation in an invading taxon is likely to be generated by the environment and recent colonisation history. Here we describe effects of the environment and colonisation history on key morphological traits of an invader (the cane toad Bufo marinus ). These "key traits" (body size and relative toxicity) mediate the impact of toads on Australian native predators, which often die as a consequence of ingesting a fatal dose of toad toxin. Measurements of museum specimens collected over >60 yr from a wide area show that seasonal variation in toad body size (due to seasonal recruitment) effectively swamps much of the spatial variance in this trait. However, relative toxicity of toads showed strong spatial variation and little seasonal variation. Thus, the risk to a native predator ingesting a toad will vary on both spatial and temporal scales. For native predators capable of eating a wide range of toad sizes (e.g. quolls, varanid lizards), seasonal variation in overall toad size will be the most significant predictor of risk. In contrast, gape-limited predators restricted to a specific range of toad sizes (such as snakes) will be most strongly affected by the relative toxicity of toads. Gape-limited predators will thus experience strong spatial variation in risk from toad consumption.     

Spatial and temporal variation of ecosystem properties at macroscales

Although spatial and temporal variation in ecological properties has been well‐studied, crucial knowledge gaps remain for studies conducted at macroscales and for ecosystem properties related to material and energy. We test four propositions of spatial and temporal variation in ecosystem properties within a macroscale (1000 km's) extent. We fit Bayesian hierarchical models to thousands of observations from over two decades to quantify four components of variation – spatial (local and regional) and temporal (local and coherent); and to model their drivers. We found strong support for three propositions: (1) spatial variation at local and regional scales are large and roughly equal, (2) annual temporal variation is mostly local rather than coherent, and, (3) spatial variation exceeds temporal variation. Our findings imply that predicting ecosystem responses to environmental changes at macroscales requires consideration of the dominant spatial signals at both local and regional scales that may overwhelm temporal signals.     

Spatial and temporal variation in patch occupancy and population density in a model system of an arctic Collembola species assemblage

We employed an experimental model system to investigate the mechanisms underlying patterns of patch occupancy and population density in a high arctic assemblage of Collembola species inhabiting a sedge tussock landscape on Svalbard. The replicate model systems consisted of 5 cores of the tussocks (habitat patches) imbedded in a barren matrix. Four of the patches were open so that animals could migrate between them, while there was one closed patch per system to test the effect of migration on extinction rate. There were model systems of two types: one with long and one with short inter‐patch distances to test the effect of patch isolation on colonisation and extinction rates. Each of the four most common collembolan species at the field site were introduced to two open patches per system (source patches), with the other two functioning as colonisation patches for the species. The experiment was run in an ecotrone over three identical, simulated arctic summers separated by winters of 3 weeks. Six replicates of systems with short and long inter‐patch distances were sampled at the end of each summer. The species varied markedly in their performance in both open arenas and closed patches, indicating differential responses to patch humidity, consistent with their differential distribution along the moisture gradient in the field site. The extinction – colonisation dynamics differed markedly between species as predicted from our field studies. This could partly be ascribed to differential dispersal and colonisation ability, but also to different tolerance to spatially variable patch quality and/or tendency for aggregative behaviour. Three of the species exhibited dynamics that superficially resemble what could be expected from classical metapopulation dynamics. However, there was a striking discrepancy between what would be expected from the effect of migration on the extinction rate of isolated patches (in particular closed patches) and the observed rates. Thus, metapopulation processes, such as stochastic colonisation and extinction events due to demographic stochasticity, were relatively unimportant compared to other sources of spatial variability among which subtle differences in patch quality are probably most important. We discuss the value of combining field studies with model system experiments, in particular when habitat quality cannot easily be measured in the field. However, our field and laboratory studies also emphasise the need for a thorough knowledge of species‐specific life history traits for making biologically sound interpretations based on both observational and experimental data.     

Spatial and temporal patterns of phenotypic variation in a Neotropical frog

Aim Studies of the spatial and temporal patterns of phenotypic diversity help to elucidate the fine‐scale evolutionary and ecological mechanisms underlying geographical differentiation. The red‐eyed tree frog, Agalychnis callidryas, is a widespread Neotropical frog that exhibits a broad range of polymorphism of coloration and flank‐stripe pattern. The goal of this study was two‐fold: first, to investigate the stability of polymorphisms over a 38‐year period; and second, to evaluate biogeographical hypotheses of diversification between lower Central American populations through quantification of phenotypic diversity on a fine geographical scale. Location This study was conducted at 12 sites across four biogeographical regions in Costa Rica and Panama. Methods We quantified colour, categorized flank‐stripe pattern from digital photos taken during field sampling, and measured body size for each individual. We compared the regional frequency of each flank‐stripe pattern in 2005 with the frequency distribution from a previous study of the same sites in 1967 using logistic regression analyses. We determined the geographical signal of leg coloration by employing linear discriminant function analyses to generate a classification matrix based on covariance similarities, and by comparison of the average hue values within and between regions. Results We found a temporal shift in the frequency of flank‐stripe patterns in three of four regions over 38 years. Based on measures of leg coloration, the frequency distribution of flank‐stripe patterns and body size, we conclude that A. callidryas populations are easily distinguishable at a regional scale. Main conclusions Agalychnis callidryas exhibits regional differentiation in all phenotypic traits measured in this study, supporting the role of three major biogeographical barriers to gene exchange. We found evidence of a putative contact zone between polytypic regions in Costa Rica. In addition, we report temporal instability of the relative frequency of stripe patterns located on the flanks. The ecological and evolutionary mechanisms that may underlie this variation include sexual selection and avoidance of predators.     

珠江口超微型浮游植物时空分布及其与环境因子的关系

对珠江口及近海区域进行了夏季和冬季超微型浮游植物(0.2-3μm)调查,分析了其时空分布及其与环境因子的关系.夏季,珠江口浮游植物密度与磷酸盐成显著正相关,且N/P远远高于30,表明浮游植物受到P限制.夏季超微型藻数量比冬季高一个数量级,其丰度与盐度成显著正相关而和营养盐(溶解性无机氮(DIN),PO4-P,SiO4-Si)显著负相关,表明珠江口超微型藻受到径流的负面影响,表现出其数量在虎门附近海域低,随着咸淡水混合程度的加剧逐渐增大的分布特征;超微型浮游植物叶绿素a在总叶绿素a中的比例也表现为河口上游低,到万山群岛附近海域达到最大,推测近海高光照、低营养盐更适宜超微型藻的生长,同时也说明超微型浮游植物适应贫营养环境的生态特点.     

Spatial and temporal variation in dispersal pattern of an invasive pine

Understanding dispersal ability of an invasive species is crucial for describing its potential spread. Despite this, we still know little about the dispersal potential of many invasive species. We explored dispersal spectra in Pinus strobus, an invasive tree in sandstone areas in Central Europe. We studied dispersal of the species using distribution of self-sown trees in the field. We compared these observed data with theoretical dispersal curves derived using information on wind speed, seed terminal velocity and tree height. Finally, we fitted various empirical dispersal curves to the observed data. All the analyses based on the observed field data were done for the whole dataset, and for the dataset divided by habitat types and age categories of the self-sown trees. P. strobus seeds can disperse up to 757.5 m from the source. The observed data fall within the confidence intervals of the predictions based on a negative exponential model. When comparing different dispersal functions fitted to the data, it was not easy to decide which of the dispersal curves provides the overall best fit. This was because different functions were the best predictors of different parts of the dispersal curve. We suggest that future studies should provide not only empirical fitted dispersal curves but also observed data and provide estimates of confidence intervals. Such information will provide insights into the reliability of the dispersal estimates in general and help to evaluate the predictive power of the different models.     

Spatial and temporal variation in pheromone composition of ant foraging trails

Many social insects use pheromones to communicate and coordinatetheir activities. Investigation of intraspecific differencesin pheromone use is a new area of social insect research. Forexample, interindividual variation in alarm pheromone contenthas been found in physical castes of polymorphic ants. Manyant species use multiple trail pheromones. Here we present novelresearch into trail pheromone variations between behavioralsubcastes of pharaoh ants, Monomorium pharaonis. Monomoriumpharaonis is attracted to trail pheromones found in its poisonglands (monomorines) and Dufour's glands (faranal). We showthat the most abundant monomorines, I (M1) and III (M3), canbe readily detected in pheromone trails. A behaviorally distinctsubcaste known as "pathfinder" foragers can relocate long-livedpheromone trails. Chemical analysis showed that pathfinder foragershad low M3:M1 ratios (mean 3.09 ± 1.53, range 1.03–7.10).Nonpathfinder foragers had significantly greater M3:M1 ratios(38.3 ± 60.0, range 3.54–289). We found that M3:M1ratio did not differ between foragers of different age but wascorrelated with behavioral subcaste at all ages. The relativeabundance of M3:M1 on foraging trails ranged from 3.03–41.3over time during pheromone trail build-up. M3:M1 ratio alsovaried spatially throughout trail networks, being lowest ontrail sections closest to a food source (M3:M1 = 1.9–3.61)and highest near the nest (M3:M1 = 67–267). Our resultsindicate a functional role for differences in pheromone trailcomposition, whereby pathfinder foragers might preferentiallymark sections of pheromone trail networks for future exploration.     

Spatial and temporal variation of phytoplankton in two subtropical Brazilian reservoirs

The purpose of this study was to verify the longitudinal distribution of phytoplankton biomass in two subtropical Brazilian reservoirs in the State of Paraná and investigate intervening factors on changes in phytoplankton biomass according to functional groups. In the Capivari and Segredo reservoirs, samples were obtained every 3 months during 2002, along a longitudinal axis (fluvial, transition, and lacustrine zones) at different depths. One hundred and eighteen taxa were identified, with Chlorophyceae as the most specious group. During the study period, both reservoirs had mostly low biomass values (less than 1 mm³ l⁻¹). The short retention time of these reservoirs constituted the principal limiting factor to phytoplankton development. Biomass values above 1 mm³ l⁻¹ were observed in the Capivari fluvial zone in March and in the Segredo lacustrine zone in December, with dominance by Microcystis aeruginosa Kütz (L_M) and Anabaena circinalis Rab. (H₁), respectively. Vertical and horizontal gradients of analyzed abiotic variables and phytoplankton biomass were observed. Considering the phytoplankton biomass values, both reservoirs were oligotrophic for the duration of the study. The Canonical Correspondence Analysis (CCA) evidenced temporal and spatial gradients of phytoplankton biomass; nevertheless, it did not follow the classic model proposed for deep reservoirs, since higher biomass was registered in the lacustrine zone during some months and in fluvial zones during other months. Distinct functional groups of phytoplankton characterized both studied reservoirs. Capivari Reservoir was best characterized by L_M and Y groups, indicative of its greater water column stability and higher phosphorus concentration, whereas Segredo Reservoir was principally characterized by the MP functional group, indicative of its greater mixing zone extension and higher nitrate concentration. The obtained results also evidenced the influence of morphometric conditions and watershed purposes as important structuring factors of phytoplankton biomass in these reservoirs. Handling editor: L. Naselli-Flores     

Spatial and temporal variation in carbon isotope discrimination in prairie graminoids

We present the results of a 5-year examination of variation in the stable carbon isotope composition () of three C₃ graminoid species from a Sandhills prairie: Agropyron smithii, Carex heliophila and Stipa comata. Although consistent species-specific patterns for mean were seen, there was also significant and substantial among-year and within-season variation in . A smaller contribution to variation in came from topographic variation among sampling sites. Effects of species, year, season and topography contribute to variation in in an additive manner. An association between climate and exists that is consistent with previous work suggesting that reflects the interplay between photosynthetic gas exchange and plant water relations. Within the growing season, the time over which integrates plant response to the environment ranges from days to months.     

Ontogenetic Variation in Blade Toughness May Contribute to the Spread of Turbinaria ornata Across the South Pacific

Coral reefs are shifting from coral to algal-dominated ecosystems worldwide. Recently, Turbinaria ornata, a marine alga native to coral reefs of the South Pacific, has spread in both range and habitat usage. Given dense stands of T. ornata can function as an alternative stable state on coral reefs, it is imperative to understand the factors that underlie its success. We tested the hypothesis that T. ornata demonstrates ontogenetic variation in allocation to anti-herbivore defense, specifically that blade toughness varied nonlinearly with thallus size. We quantified the relationship between T. ornata blade toughness and thallus size for individual thalli within algal stands (N = 345) on seven fringing reefs along the north shore of Moorea, French Polynesia. We found that blade toughness was greatest at intermediate sizes that typically form canopies, with overall reduced toughness in both smaller individuals that refuge within the understory and older reproductive individuals that ultimately detach and form floating rafts. We posit this variation in blade toughness reduces herbivory on the thalli that are most exposed to herbivores and may facilitate reproduction in dispersing stages, both of which may aid the proliferation of T. ornata.     

Spatial and temporal variation in islands of fertility in the Sonoran Desert

In many arid and semi-arid ecosystems, canopy trees and shrubs have a strong positive influence on soil moisture and nutrient availability, creating islands of fertility where organic matter and nutrients are high relative to areas outside the canopy. Previous studies of canopy effects on soil processes have rarely considered how landscape context may modulate these effects. We measured the effects of velvet mesquite trees (Prosopis velutina) on soil moisture and the biogeochemistry of nitrogen at different positions along a topographic gradient from upland desert to riparian zone in the Sonoran Desert of central Arizona. We also examined how landscape position and patterns of precipitation interact to determine the influence of P. velutina on soil moisture, N availability assessed using ion exchange resins, net N mineralization and net nitrification, and microbial biomass C and N. P. velutina clearly created islands of fertility with higher soil organic matter, net N mineralization and net nitrification rates, and microbial biomass under mesquite canopies. These effects were consistent across the landscape and showed little temporal variability. Magnitude and direction of effect of mesquite on soil moisture changed with landscape position, from positive in the upland to negative in the terrace, but only when soil moisture was >4%. Resin N showed responses to mesquite that depended on precipitation and topographic position, with highest values during wet seasons and under mesquite on terraces. We suggest changes in proximity of P. velutina to groundwater lead to shifts in biogeochemical processes and species interactions with change in landscape position along a topographic gradient.