WorldWideScience

Sample records for static species distribution

  1. Static Load Distribution in Ball Bearings

    Science.gov (United States)

    Ricci, Mario

    2010-01-01

    A numerical procedure for computing the internal loading distribution in statically loaded, single-row, angular-contact ball bearings when subjected to a known combined radial and thrust load is presented. The combined radial and thrust load must be applied in order to avoid tilting between inner and outer rings. The numerical procedure requires the iterative solution of Z + 2 simultaneous nonlinear equations - where Z is the number of the balls - to yield an exact solution for axial and radial deflections, and contact angles. Numerical results for a 218 angular-contact ball bearing have been compared with those from the literature and show significant differences in the magnitudes of the ball loads, contact angles, and the extent of the loading zone.

  2. The electromagnetic momentum of static charge-current distributions

    OpenAIRE

    Franklin, Jerrold

    2013-01-01

    The origin of electromagnetic momentum for general static charge-current distributions is examined. The electromagnetic momentum for static electromagnetic fields is derived by implementing conservation of momentum for the sum of mechanical momentum and electromagnetic momentum. The external force required to keep matter at rest during the production of the final static configuration produces the electromagnetic momentum. Examples of the electromagnetic momentum in static electric and magneti...

  3. Hierarchical species distribution models

    Science.gov (United States)

    Hefley, Trevor J.; Hooten, Mevin B.

    2016-01-01

    Determining the distribution pattern of a species is important to increase scientific knowledge, inform management decisions, and conserve biodiversity. To infer spatial and temporal patterns, species distribution models have been developed for use with many sampling designs and types of data. Recently, it has been shown that count, presence-absence, and presence-only data can be conceptualized as arising from a point process distribution. Therefore, it is important to understand properties of the point process distribution. We examine how the hierarchical species distribution modeling framework has been used to incorporate a wide array of regression and theory-based components while accounting for the data collection process and making use of auxiliary information. The hierarchical modeling framework allows us to demonstrate how several commonly used species distribution models can be derived from the point process distribution, highlight areas of potential overlap between different models, and suggest areas where further research is needed.

  4. Species Distribution Modelling

    DEFF Research Database (Denmark)

    Gomes, Vitor H. F.; Ijff, Stephanie D.; Raes, Niels

    2018-01-01

    Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SD...

  5. Bounding Species Distribution Models

    Science.gov (United States)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  6. Contribution of static and dynamic load balancing in a real-time distributed air defence simulation

    CSIR Research Space (South Africa)

    Duvenhage, B

    2008-05-01

    Full Text Available the analysis and the available literature the appropriate metrics and a static load balancing heuristic is chosen and its performance compared to that of the statistical static load balancing. The dynamic suitability of the static load balancing schemes... metrics are applied to these distributions to find a subset of metrics applicable to static load balancing and a static load balancing heuristic. 3.1 The Static Optimisation Problem A simple way to perform static load balancing is to randomly assign...

  7. Distribution of incremental static stress caused by earthquakes

    Directory of Open Access Journals (Sweden)

    Y. Y. Kagan

    1994-01-01

    Full Text Available Theoretical calculations, simulations and measurements of rotation of earthquake focal mechanisms suggest that the stress in earthquake focal zones follows the Cauchy distribution which is one of the stable probability distributions (with the value of the exponent α equal to 1. We review the properties of the stable distributions and show that the Cauchy distribution is expected to approximate the stress caused by earthquakes occurring over geologically long intervals of a fault zone development. However, the stress caused by recent earthquakes recorded in instrumental catalogues, should follow symmetric stable distributions with the value of α significantly less than one. This is explained by a fractal distribution of earthquake hypocentres: the dimension of a hypocentre set, ��, is close to zero for short-term earthquake catalogues and asymptotically approaches 2¼ for long-time intervals. We use the Harvard catalogue of seismic moment tensor solutions to investigate the distribution of incremental static stress caused by earthquakes. The stress measured in the focal zone of each event is approximated by stable distributions. In agreement with theoretical considerations, the exponent value of the distribution approaches zero as the time span of an earthquake catalogue (ΔT decreases. For large stress values α increases. We surmise that it is caused by the δ increase for small inter-earthquake distances due to location errors.

  8. Static trace free Einstein equations and stellar distributions

    Science.gov (United States)

    Hansraj, Sudan; Goswami, Rituparno; Mkhize, Njabulo; Ellis, George

    2017-08-01

    We construct models of static spherical distributions of the perfect fluid in trace free Einstein gravity theory. The equations governing the gravitational field are equivalent to standard Einstein's equations; however, their presentation is manifestly different, which motivates the question whether new information would emerge due to the nonlinearity of the field equations. The incompressible fluid assumption does not lead to the well known Schwarzschild interior metric of Einstein gravity, and a term denoting the presence of a cosmological constant is present on account of the integration process. The Schwarzschild interior is regained as a special case of a richer geometry. On the other hand, when the Schwarzschild geometry is prescribed, a constant density fluid emerges consistent with the standard equations. A complete model of an isothermal fluid sphere with pressure and density obeying the inverse square law is obtained. Corrections to the model previously presented in the literature by Saslaw et al. are exhibited. The isothermal ansatz does not yield a constant gravitational potential in general, but both potentials are position dependent. Conversely, it is shown that assuming a constant gr r gravitational potential does not yield an isothermal fluid in general as is the case in standard general relativity. The results of the standard Einstein equations are special cases of the models reported here. Noteworthy is the fact that whereas the previously reported isothermal solution was only of cosmological interest, the solution reported herein admits compact objects by virtue of the fact that a pressure free hypersurface exists. Finally we analyze the consequences of selecting the Finch-Skea metric as the seed solution. The density profiles match; however, there is a deviation between the pressure profiles with the Einstein case although the qualitative behavior is the same. It is shown in detail that the model satisfies elementary requirements for physical

  9. First-principles derivation of static avalanche-size distributions.

    Science.gov (United States)

    Le Doussal, Pierre; Wiese, Kay Jörg

    2012-06-01

    We study the energy minimization problem for an elastic interface in a random potential plus a quadratic well. As the position of the well is varied, the ground state undergoes jumps, called shocks or static avalanches. We introduce an efficient and systematic method to compute the statistics of avalanche sizes and manifold displacements. The tree-level calculation, i.e., mean-field limit, is obtained by solving a saddle-point equation. Graphically, it can be interpreted as the sum of all tree graphs. The 1-loop corrections are computed using results from the functional renormalization group. At the upper critical dimension the shock statistics is described by the Brownian force model (BFM), the static version of the so-called Alessandro-Beatrice-Bertotti-Montorsi (ABBM) model in the nonequilibrium context of depinning. This model can itself be treated exactly in any dimension and its shock statistics is that of a Lévy process. Contact is made with classical results in probability theory on the Burgers equation with Brownian initial conditions. In particular we obtain a functional extension of an evolution equation introduced by Carraro and Duchon, which recursively constructs the tree diagrams in the field theory.

  10. Statics and Dynamics of Selfish Interactions in Distributed Service Systems.

    Directory of Open Access Journals (Sweden)

    Fabrizio Altarelli

    Full Text Available We study a class of games which models the competition among agents to access some service provided by distributed service units and which exhibits congestion and frustration phenomena when service units have limited capacity. We propose a technique, based on the cavity method of statistical physics, to characterize the full spectrum of Nash equilibria of the game. The analysis reveals a large variety of equilibria, with very different statistical properties. Natural selfish dynamics, such as best-response, usually tend to large-utility equilibria, even though those of smaller utility are exponentially more numerous. Interestingly, the latter actually can be reached by selecting the initial conditions of the best-response dynamics close to the saturation limit of the service unit capacities. We also study a more realistic stochastic variant of the game by means of a simple and effective approximation of the average over the random parameters, showing that the properties of the average-case Nash equilibria are qualitatively similar to the deterministic ones.

  11. Taking species abundance distributions beyond individuals

    NARCIS (Netherlands)

    Morlon, Helene; White, Ethan P.; Etienne, Rampal S.; Green, Jessica L.; Ostling, Annette; Alonso, David; Enquist, Brian J.; He, Fangliang; Hurlbert, Allen; Magurran, Anne E.; Maurer, Brian A.; McGill, Brian J.; Olff, Han; Storch, David; Zillio, Tommaso; Chave, Jérôme

    The species abundance distribution (SAD) is one of the few universal patterns in ecology. Research on this fundamental distribution has primarily focused on the study of numerical counts, irrespective of the traits of individuals. Here we show that considering a set of Generalized Species Abundance

  12. The roles of competition and habitat in the dynamics of populations and species distributions Ecology

    Science.gov (United States)

    Charles B. Yackulic; Janice Reid; James D. Nichols; James E. Hines; Raymond Davis; Eric Forsman

    2014-01-01

    The role of competition in structuring biotic communities at fine spatial scales is well known from detailed process-based studies. Our understanding of competition’s importance at broader scales is less resolved and mainly based on static species distribution maps. Here, we bridge this gap by examining the joint occupancy dynamics of an invading species (Barred Owl,...

  13. Combining Static Analysis and Runtime Checking in Security Aspects for Distributed Tuple Spaces

    DEFF Research Database (Denmark)

    Yang, Fan; Aotani, Tomoyuki; Masuhara, Hidehiko

    2011-01-01

    analysis predicates and functions that provide information on future behavior of a program. With a dual value evaluation mechanism that handles results of static analysis and runtime values at the same time, those functions and predicates enable the users to specify security policies in a uniform manner....... Our two-staged implementation strategy gathers fundamental static analysis information at load-time, so as to avoid performing all analysis at runtime. We built a compiler for AspectKE*, and successfully implemented security aspects for a distributed chat system and an electronic healthcare record......Enforcing security policies to distributed systems is difficult, in particular, to a system containing untrusted components. We designed AspectKE*, an aspect-oriented programming language based on distributed tuple spaces to tackle this issue. One of the key features in AspectKE* is the program...

  14. New trends in species distribution modelling

    Science.gov (United States)

    Zimmermann, Niklaus E.; Edwards, Thomas C.; Graham, Catherine H.; Pearman, Peter B.; Svenning, Jens-Christian

    2010-01-01

    Species distribution modelling has its origin in the late 1970s when computing capacity was limited. Early work in the field concentrated mostly on the development of methods to model effectively the shape of a species' response to environmental gradients (Austin 1987, Austin et al. 1990). The methodology and its framework were summarized in reviews 10–15 yr ago (Franklin 1995, Guisan and Zimmermann 2000), and these syntheses are still widely used as reference landmarks in the current distribution modelling literature. However, enormous advancements have occurred over the last decade, with hundreds – if not thousands – of publications on species distribution model (SDM) methodologies and their application to a broad set of conservation, ecological and evolutionary questions. With this special issue, originating from the third of a set of specialized SDM workshops (2008 Riederalp) entitled 'The Utility of Species Distribution Models as Tools for Conservation Ecology', we reflect on current trends and the progress achieved over the last decade.

  15. ESUSA: US endangered species distribution file

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, J.; Calef, C.E.

    1979-10-01

    This report describes a file containing distribution data on endangered species of the United States of Federal concern pursuant to the Endangered Species Act of 1973. Included for each species are (a) the common name, (b) the scientific name, (c) the family, (d) the group (mammal, bird, etc.), (e) Fish and Wildlife Service (FWS) listing and recovery priorities, (f) the Federal legal status, (g) the geographic distribution by counties or islands, (h) Federal Register citations and (i) the sources of the information on distribution of the species. Status types are endangered, threatened, proposed, formally under review, candidate, deleted, and rejected. Distribution is by Federal Information Processing Standard (FIPS) county code and is of four types: designated critical habitat, present range, potential range, and historic range.

  16. species composition, relative abundance and distribution

    African Journals Online (AJOL)

    Preferred Customer

    habitat size (Willis, 1979), foraging modes. (Marone, 1991) and floristic composition (Wiens and Rotenberry, 1981) have influence in the distribution of the species. The highest number of avian species was observed in the forest habitat. This is probably due to the diversity of vegetation that provided heterogeneous habitat ...

  17. Finessing atlas data for species distribution models

    NARCIS (Netherlands)

    Niamir, A.; Skidmore, A.K.; Toxopeus, A.G.; Munoz, A.R.; Real, R.

    2011-01-01

    Aim The spatial resolution of species atlases and therefore resulting model predictions are often too coarse for local applications. Collecting distribution data at a finer resolution for large numbers of species requires a comprehensive sampling effort, making it impractical and expensive. This

  18. Distribution of crayfish species in Hungarian waters

    NARCIS (Netherlands)

    Mercédesz, Ludányi; Peeters, E.T.H.M.; Kiss, B.; Roessink, I.

    2016-01-01

    Three native crayfish species, i.e.~Astacus astacus, Astacus leptodactylus and Austropotamobius torrentium, occur in Hungary. Lately, however, non-indigenous crustaceans have also invaded the country Their most recent distribution and impact on the occurrences of the native species is not clear.

  19. Species Distribution and Antibiotic Resistance in Coagulase ...

    African Journals Online (AJOL)

    Erah

    antimicrobial resistance in the community. Methods: The isolates were identified to the species level by conventional methods, and their susceptibility to 20 antibiotics was tested by disk diffusion and to vancomycin by agar dilution. Results: The species distribution was as follows: Staphylococcus epidermidis 45 (30.2 %), S.

  20. Incorporating Context Dependency of Species Interactions in Species Distribution Models.

    Science.gov (United States)

    Lany, Nina K; Zarnetske, Phoebe L; Gouhier, Tarik C; Menge, Bruce A

    2017-07-01

    Species distribution models typically use correlative approaches that characterize the species-environment relationship using occurrence or abundance data for a single species. However, species distributions are determined by both abiotic conditions and biotic interactions with other species in the community. Therefore, climate change is expected to impact species through direct effects on their physiology and indirect effects propagated through their resources, predators, competitors, or mutualists. Furthermore, the sign and strength of species interactions can change according to abiotic conditions, resulting in context-dependent species interactions that may change across space or with climate change. Here, we incorporated the context dependency of species interactions into a dynamic species distribution model. We developed a multi-species model that uses a time-series of observational survey data to evaluate how abiotic conditions and species interactions affect the dynamics of three rocky intertidal species. The model further distinguishes between the direct effects of abiotic conditions on abundance and the indirect effects propagated through interactions with other species. We apply the model to keystone predation by the sea star Pisaster ochraceus on the mussel Mytilus californianus and the barnacle Balanus glandula in the rocky intertidal zone of the Pacific coast, USA. Our method indicated that biotic interactions between P. ochraceus and B. glandula affected B. glandula dynamics across >1000 km of coastline. Consistent with patterns from keystone predation, the growth rate of B. glandula varied according to the abundance of P. ochraceus in the previous year. The data and the model did not indicate that the strength of keystone predation by P. ochraceus varied with a mean annual upwelling index. Balanus glandula cover increased following years with high phytoplankton abundance measured as mean annual chlorophyll-a. M. californianus exhibited the same

  1. Numerical computation of electromagnetic field for general static and axisymmetric current distribution

    Science.gov (United States)

    Fukushima, Toshio

    2017-12-01

    We developed a numerical method to compute the electromagnetic field of arbitrary static and axisymmetric current distribution. The method (i) numerically evaluates a double integral of the electrostatic and magnetostatic potentials of an infinitely thin ring current by the split quadrature method using the double exponential rules, and (ii) derives the electrostatic field and the magnetostatic induction by numerically differentiating the numerically integrated potentials by the central difference formula. A comparison with the exact solution for a poloidal current distribution with an anisotropic Gaussian damping confirmed the 14- and 9-digit accuracy of the potential and the field/induction computed by the new method.

  2. Forms and genesis of species abundance distributions

    Directory of Open Access Journals (Sweden)

    Evans O. Ochiaga

    2015-12-01

    Full Text Available Species abundance distribution (SAD is one of the most important metrics in community ecology. SAD curves take a hollow or hyperbolic shape in a histogram plot with many rare species and only a few common species. In general, the shape of SAD is largely log-normally distributed, although the mechanism behind this particular SAD shape still remains elusive. Here, we aim to review four major parametric forms of SAD and three contending mechanisms that could potentially explain this highly skewed form of SAD. The parametric forms reviewed here include log series, negative binomial, lognormal and geometric distributions. The mechanisms reviewed here include the maximum entropy theory of ecology, neutral theory and the theory of proportionate effect.

  3. Aeromonas update: new species and global distribution.

    Science.gov (United States)

    Carnahan, A M; Joseph, S W

    1991-05-15

    There are currently eight proposed or validated Aeromonas spp. of which five have been implicated in human disease: A. hydrophila, A. sobria, A. caviae, A. veronii, and A. schubertii. Recent studies have extended the geographic distribution and source of isolation of the newer species and resulted in the possibility of two new species, A. jandaei and A. trota, from diarrheal, wound, blood and environmental sources.

  4. Static Equivalent of Distribution Grids With High Penetration of PV Systems

    DEFF Research Database (Denmark)

    Samadi, Afshin; Söder, Lennart; Shayesteh, Ebrahim

    2015-01-01

    High penetrations of photovoltaic (PV) systems within load pockets in distribution grids have changed pure consumers to prosumers. This can cause technical challenges in distribution and transmission grids, such as overvoltage and reverse power flow. Embedding voltage support schemes into PVs...... equivalent that can fairly capture the dominant behavior of the distribution grids. The aim of this paper is to use gray-box modeling concepts to develop a static equivalent of distribution grids comprising a large number of PV systems embedded with voltage support schemes. In the proposed model, the PV...... systems are aggregated as a separate entity, and not as a negative load, which is traditionally done. The results demonstrate the superior quality of the proposed model compared with the model with PV systems as the negative load....

  5. ESUSA: U. S. endangered species distribution file

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, J; Calef, C E

    1978-05-01

    A file containing distribution data on federally listed or proposed endangered species of the United States is described. Included are (a) the common name, (b) the scientific name, (c) the taxonomic family, (d) the OES/FWS/USDI group (mammal, bird, etc.), (e) the status, (f) the geographic distribution by counties, and (g) Federal Register references. Status types are endangered, threatened, proposed, under review, deleted, and rejected. Distribution is by Federal Information Processing Standard (FIPS) county code and is of four types: designated critical habitat, present range, potential range, and historic range. The file is currently being used in conjunction with similar data on projected future energy facilities to anticipate possible conflicts. However, the file would be useful to any project correlating endangered species with location information expressed by county. An example is as an aid in evaluating Forest Service or Bureau of Land Management proposed wilderness areas.

  6. On the myths of indicator species: issues and further consideration in the use of static concepts for ecological applications.

    Directory of Open Access Journals (Sweden)

    Michael L Zettler

    Full Text Available The use of static indicator species, in which species are expected to have a similar sensitivity or tolerance to either natural or human-induced stressors, does not account for possible shifts in tolerance along natural environmental gradients and between biogeographic regions. Their indicative value may therefore be considered at least questionable. In this paper we demonstrate how species responses (i.e. abundance to changes in sediment grain size and organic matter (OM alter along a salinity gradient and conclude with a plea for prudency when interpreting static indicator-based quality indices. Six model species (three polychaetes, one amphipod and two bivalves from the North Sea, Baltic Sea and the Mediterranean Sea region were selected. Our study demonstrated that there were no generic relationships between environment and biota and half of the studied species showed different responses in different seas. Consequently, the following points have to be carefully considered when applying static indicator-based quality indices: (1 species tolerances and preferences may change along environmental gradients and between different biogeographic regions, (2 as environment modifies species autecology, there is a need to adjust indicator species lists along major environmental gradients and (3 there is a risk of including sibling or cryptic species in calculating the index value of a species.

  7. Cumulative frequency distribution of past species extinctions

    Science.gov (United States)

    Raup, D. M.

    1991-01-01

    Analysis of Sepkoski's compendium of the time ranges of 30,000+ taxa yields a mean duration of 28.4 ma for genera of fossil invertebrates. This converts to an average extinction rate of 3.5 percent per million years or about one percent every 286,000 years. Using survivorship techniques, these estimates can be converted to the species level, yielding a Phanerozoic average of one percent species extinction every 40,000 years. Variation in extinction rates through time is far greater than the null expectation of a homogeneous birth-death model and this reflects the well-known episodicity of extinction ranging from a few large mass extinctions to so-called background extinction. The observed variation in rates can be used to construct a cumulative frequency distribution of extinction intensity, and this distribution, in the form of a kill curve for species, shows the expected waiting times between extinction events of a given intensity. The kill curve is an average description of the extinction events of a given intensity. The kill curve is an average description of the extinction record and does not imply any cause or causes of extinction. The kill curve shows, among other things, that only about five percent of total species extinctions in the Phanerozoic were involved in the five largest mass extinctions. The other 95 percent were distributed among large and small events not normally called mass extinctions. As an exploration of the possibly absurd proposition that most past extinctions were produced by the effects of large-body impact, the kill curve for species was mapped on the comparable distribution for comet and asteroid impacts. The result is a curve predicting the species kill for a given size of impacting object (expressed as crater size). The results are reasonable in that impacts producing craters less than 30 km (diameter) cause negligible extinction but those producing craters 100-150 km (diameter) cause extinction of species in the range of 45

  8. A laser speckle sensor to measure the distribution of static torsion angles of twisted targets

    DEFF Research Database (Denmark)

    Rose, B.; Imam, H.; Hanson, Steen Grüner

    1998-01-01

    A novel method for measuring the distribution of static torsion angles of twisted targets is presented. The method is based on Fourier transforming the scattered field in the direction perpendicular to the twist axis, while performing an imaging operation in the direction parallel to the axis....... A cylindrical lens serves to image the closely spaced lateral positions of the target along the twist axis onto corresponding lines of the two dimensional image sensor. Thus, every single line of the image sensor measures the torsion angle of the corresponding surface position along the twist axis of the target....... Experimentally, we measure the distribution of torsion angles in both uniform and non-uniform deformation zones. It is demonstrated both theoretically and experimentally that the measurements are insensitive to object shape and target distance if the image sensor is placed in the Fourier plane. A straightforward...

  9. Big data of tree species distributions

    DEFF Research Database (Denmark)

    Serra-Diaz, Josep M.; Enquist, Brian J.; Maitner, Brian

    2018-01-01

    are currently available in big databases, several challenges hamper their use, notably geolocation problems and taxonomic uncertainty. Further, we lack a complete picture of the data coverage and quality assessment for open/public databases of tree occurrences. Methods: We combined data from five major....... Conclusions: Our geographical coverage analysis shows that a wealth of easily accessible data exist on tree species occurrences worldwide, but regional gaps and coordinate errors are abundant. Thus, assessment of tree distributions will need accurate occurrence quality control protocols and key collaborations......Background: Trees play crucial roles in the biosphere and societies worldwide, with a total of 60,065 tree species currently identified. Increasingly, a large amount of data on tree species occurrences is being generated worldwide: from inventories to pressed plants. While many of these data...

  10. Development and application of a species sensitivity distribution for temperature-induced mortality in the aquatic environment

    NARCIS (Netherlands)

    Vries, de P.; Tamis, J.E.; Murk, A.J.; Smit, M.G.D.

    2008-01-01

    Current European legislation has static water quality objectives for temperature effects, based on the most sensitive species. In the present study a species sensitivity distribution (SSD) for elevated temperatures is developed on the basis of temperature sensitivity data (mortality) of 50 aquatic

  11. Node-based analysis of species distributions

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Rahbek, Carsten; Fjeldså, Jon

    2014-01-01

    of intuitively interpretable patterns that are consistent with current biogeographical knowledge.Importantly, the results are statistically tractable, opening many possibilities for their use in analyses of evolutionary, historical and spatial patterns of species diversity. The method is implemented...... overrepresentation score (SOS) and the geographic node divergence (GND) score, which together combine ecological and evolutionary patterns into a single framework and avoids many of the problems that characterize community phylogenetic methods in current use.This approach goes through each node in the phylogeny...... with case studies on two groups with well-described biogeographical histories: a local-scale community data set of hummingbirds in the North Andes, and a large-scale data set of the distribution of all species of New World flycatchers. The node-based analysis of these two groups generates a set...

  12. Gridded Species Distribution, Version 1: Global Amphibians Presence Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Amphibians Presence Grids of the Gridded Species Distribution, Version 1 is a reclassified version of the original grids of amphibian species distribution...

  13. Design of a Control Scheme for Distribution Static Synchronous Compensators with Power-Quality Improvement Capability

    Directory of Open Access Journals (Sweden)

    Pedro Roncero-Sànchez

    2014-04-01

    Full Text Available Electric power systems are among the greatest achievements of the last century. Today, important issues, such as an ever-increasing demand, the flexible and reliable integration of distributed generation or a growth in disturbing loads, must be borne in mind. In this context, smart grids play a key role, allowing better efficiency of power systems. Power electronics provides solutions to the aforementioned matters, since it allows various energy sources to be integrated into smart grids. Nevertheless, the design of the various control schemes that are necessary for the correct operation of the power-electronic interface is a very important issue that must always be taken into consideration. This paper deals with the design of the control system of a distribution static synchronous compensator (DSTATCOM based on flying-capacitor multilevel converters. The control system is tailored to compensate for both voltage sags by means of reactive-power injection and voltage imbalances caused by unbalanced loads. The design of the overall control is carried out by using the root-locus and frequency-response techniques, improving both the transient response and the steady-state error of the closed-loop system. Simulation results obtained using PSCADTM/EMTDCTM (Manitoba Hydro International Ltd., Commerce Drive, Winnipeg, MB, Canada show the resultant voltage regulation.

  14. 3-D model-based frame interpolation for distributed video coding of static scenes.

    Science.gov (United States)

    Maitre, Matthieu; Guillemot, Christine; Morin, Luce

    2007-05-01

    This paper addresses the problem of side information extraction for distributed coding of videos captured by a camera moving in a 3-D static environment. Examples of targeted applications are augmented reality, remote-controlled robots operating in hazardous environments, or remote exploration by drones. It explores the benefits of the structure-from-motion paradigm for distributed coding of this type of video content. Two interpolation methods constrained by the scene geometry, based either on block matching along epipolar lines or on 3-D mesh fitting, are first developed. These techniques are based on a robust algorithm for sub-pel matching of feature points, which leads to semi-dense correspondences between key frames. However, their rate-distortion (RD) performances are limited by misalignments between the side information and the actual Wyner-Ziv (WZ) frames due to the assumption of linear motion between key frames. To cope with this problem, two feature point tracking techniques are introduced, which recover the camera parameters of the WZ frames. A first technique, in which the frames remain encoded separately, performs tracking at the decoder and leads to significant RD performance gains. A second technique further improves the RD performances by allowing a limited tracking at the encoder. As an additional benefit, statistics on tracks allow the encoder to adapt the key frame frequency to the video motion content.

  15. Measuring static seated pressure distributions and risk for skin pressure ulceration in ice sledge hockey players.

    Science.gov (United States)

    Darrah, Shaun D; Dicianno, Brad E; Berthold, Justin; McCoy, Andrew; Haas, Matthew; Cooper, Rory A

    2016-01-01

    To determine whether sledge hockey players with physical disability have higher average seated pressures compared to non-disabled controls. Fifteen age-matched controls without physical disability and 15 experimental participants with physical disability were studied using a pressure mapping device to determine risk for skin pressure ulceration and the impact of cushioning and knee angle positioning on seated pressure distributions. Regardless of participant group, cushioning, or knee angle, average seated pressures exceeded clinically acceptable seated pressures. Controls had significantly higher average seated pressures than the disability group when knees were flexed, both with the cushion (p = 0.013) and without (p = 0.015). Knee extension showed significantly lower average pressures in controls, both with the cushion (p hockey players utilize positioning with larger knee flexion angles. Implications for Rehabilitation Ice sledge hockey is a fast growing adaptive sport. Adaptive sports have been associated with several positive improvements in overall health and quality of life, though may be putting players at risk for skin ulceration. Measured static seated pressure in sledges greatly exceeds current clinically accepted clinical guidelines. With modern improvements in wheelchair pressure relief/cushioning there are potential methods for improvement of elevated seated pressure in ice hockey sledges.

  16. Static and Dynamic Stability Analysis of Distributed Energy Resources Components with Storage Devices and Loads for Smart Grids

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Groza, V.

    2011-01-01

    of the Smart Grids (SGs). A SG can operate interconnected to the main distribution grid or in islanded mode. This paper presents experimental tests for static and dynamic stability analysis carried out in a dedicated laboratory for research in distributed control and smart grid with a high share of renewable...... are required under different operation modes and loads. The testing reporting here includes three modes of operation: stand alone, parallel/hybrid and grid connection....

  17. Field Distribution of Transcranial Static Magnetic Stimulation in Realistic Human Head Model.

    Science.gov (United States)

    Tharayil, Joseph J; Goetz, Stefan M; Bernabei, John M; Peterchev, Angel V

    2017-10-10

    The objective of this work was to characterize the magnetic field (B-field) that arises in a human brain model from the application of transcranial static magnetic field stimulation (tSMS). The spatial distribution of the B-field magnitude and gradient of a cylindrical, 5.08 cm × 2.54 cm NdFeB magnet were simulated in air and in a human head model using the finite element method and calibrated with measurements in air. The B-field was simulated for magnet placements over prefrontal, motor, sensory, and visual cortex targets. The impact of magnetic susceptibility of head tissues on the B-field was quantified. Peak B-field magnitude and gradient respectively ranged from 179-245 mT and from 13.3-19.0 T/m across the cortical targets. B-field magnitude, focality, and gradient decreased with magnet-cortex distance. The variation in B-field strength and gradient across the anatomical targets largely arose from the magnet-cortex distance. Head magnetic susceptibilities had negligible impact on the B-field characteristics. The half-maximum focality of the tSMS B-field ranged from 7-12 cm3 . This is the first presentation and characterization of the three-dimensional (3D) spatial distribution of the B-field generated in a human brain model by tSMS. These data can provide quantitative dosing guidance for tSMS applications across various cortical targets and subjects. The finding that the B-field gradient is high near the magnet edges should be considered in studies where neural tissue is placed close to the magnet. The observation that susceptibility has negligible effects confirms assumptions in the literature. © 2017 International Neuromodulation Society.

  18. Multiple modes in a coral species abundance distribution.

    Science.gov (United States)

    Dornelas, Maria; Connolly, Sean R

    2008-10-01

    Species abundance distributions are an important measure of biodiversity and community structure. These distributions are affected by sampling, and alternative species-abundance models often make similar predictions for small sample sizes. Very large samples reveal the relative abundances of rare species, and thus provide information about species relative abundances that small samples cannot. Here, we present the species-abundance distribution for a sample of > 40,000 coral colonies at a single site, exceeding existing samples of coral local assemblages by over an order of magnitude. This abundance distribution is multimodal when examined on a logarithmic scale. Four different model selection procedures all indicate that the underlying community abundance distribution has at least three modes. We show that the multiple modes are not caused by mixtures of species with different habitat preferences. However, spatial aggregation partially explains our results. We inspect published work on species abundance distributions, and suggest that multimodality may be a common feature of large samples.

  19. Equilibrium of Global Amphibian Species Distributions with Climate

    Science.gov (United States)

    Munguía, Mariana; Rahbek, Carsten; Rangel, Thiago F.; Diniz-Filho, Jose Alexandre F.; Araújo, Miguel B.

    2012-01-01

    A common assumption in bioclimatic envelope modeling is that species distributions are in equilibrium with contemporary climate. A number of studies have measured departures from equilibrium in species distributions in particular regions, but such investigations were never carried out for a complete lineage across its entire distribution. We measure departures of equilibrium with contemporary climate for the distributions of the world amphibian species. Specifically, we fitted bioclimatic envelopes for 5544 species using three presence-only models. We then measured the proportion of the modeled envelope that is currently occupied by the species, as a metric of equilibrium of species distributions with climate. The assumption was that the greater the difference between modeled bioclimatic envelope and the occupied distribution, the greater the likelihood that species distribution would not be at equilibrium with contemporary climate. On average, amphibians occupied 30% to 57% of their potential distributions. Although patterns differed across regions, there were no significant differences among lineages. Species in the Neotropic, Afrotropics, Indo-Malay, and Palaearctic occupied a smaller proportion of their potential distributions than species in the Nearctic, Madagascar, and Australasia. We acknowledge that our models underestimate non equilibrium, and discuss potential reasons for the observed patterns. From a modeling perspective our results support the view that at global scale bioclimatic envelope models might perform similarly across lineages but differently across regions. PMID:22511938

  20. species composition, relative abundance and distribution

    African Journals Online (AJOL)

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    migratory breeding in the Palaearctic region and. 69 are mainly African (south of the Sahara desert) or tropical species which also occur in the. Palaearctic region. There are 199 Palaearctic winter visitors in Ethiopia, including 21 passage migrants. Of these, 169 are only visitors with no resident forms. There are 47 species, ...

  1. Evolution in a fully constituted world: Charles Darwin's debts towards a static world in the Origin of Species (1859).

    Science.gov (United States)

    Delisle, Richard G

    2014-01-01

    The Transformist Revolution was a long intellectual quest that has expanded from the 18th century to today. One area of inquiry after another has confronted the necessity of recasting its object of study under an evolutionary view: human history, geology, biology, astronomy, etc. No single scholar fully managed to make the transition from a static worldview to an evolutionary one during his or her own lifetime; Charles Darwin is no exception. Many versions of evolutionism were proposed during this revolution, versions offering all sorts of compromises between old and new views. Not sufficiently acknowledged in the historiography is the profoundness of Darwin's debts towards the old static view. As a dual child of the Scientific Revolution and natural theology, Darwin inherited key concepts such as stability, completeness, timelessness, unity, permanence, and uniformity. Darwin took these concepts into consideration while erecting his theory of biological evolution. Unsurprisingly, this theory was ill-equipped to embrace the directionality, historicity, and novelty that came along with a new evolutionary world. This paper analyses a fundamental idea at the heart of Darwin's Origins of Species (1859) inherited from a static, stable, and machine-like conception of the world: the notion of a fully constituted world. Although in principle antithetical to the very idea of evolution itself, Darwin found a way to 'loosen up' this notion so as to retain it in a way that allows for some kind of evolutionary change. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Hyperspectral remote sensing of vegetation species distribution in a saltmarsh

    NARCIS (Netherlands)

    Schmidt, K.S.

    2003-01-01

    The availability of quality empirical data on vegetation species distribution is a major factor limiting the understanding, if not resolution, of many nature conservation issues. Accurate knowledge of the distribution of plant species can form a critical component for managing ecosystems and

  3. Comparing the performance of species distribution models of

    NARCIS (Netherlands)

    Valle , M.; van Katwijk, M.M.; de Jong, D.J.; Bouma, T.; Schipper, A.M.; Chust, G.; Benito, B.M.; Garmendia, J.M.; Borja, A.

    2013-01-01

    Intertidal seagrasses show high variability in their extent and location, with local extinctions and (re-)colonizations being inherent in their population dynamics. Suitable habitats are identified usually using Species Distribution Models (SDM), based upon the overall distribution of the species;

  4. Species Distribution and Antibiotic Resistance in Coagulase ...

    African Journals Online (AJOL)

    Purpose: The antimicrobial susceptibility of 149 coagulase-negative staphylococci (CoNS) isolates from faecal samples of children in Ile-Ife, Nigeria, was evaluated in order to determine their contribution to antimicrobial resistance in the community. Methods: The isolates were identified to the species level by conventional ...

  5. A Species Distribution Modeling Informed Conservation Assessment of Bog Spicebush

    Science.gov (United States)

    2016-09-14

    likely dynamic, with metapopulation processes affect- ing recruitment into sites that vary in suitability over time and space . Alt- hough Bog Spicebush...Schwartz 2009. Using species distribution models to predict new occurrences for rare plants. Diversity and Distributions 15:565-576. Wintle, B. A. and...ER D C/ CE RL T R- 16 -3 1 A Species Distribution Modeling Informed Conservation Assessment of Bog Spicebush Co ns tr uc tio n En gi ne

  6. Effects of tree species composition on within-forest distribution of understorey species

    NARCIS (Netherlands)

    Oijen, van D.; Feijen, M.; Hommel, P.W.F.M.; Ouden, den J.; Waal, de R.W.

    2005-01-01

    Question: Do tree species, with different litter qualities, affect the within-forest distribution of forest understorey species on intermediate to base-rich soils? Since habitat loss and fragmentation have caused ancient forest species to decline, those species are the main focus of this study.

  7. Species distributions, quantum theory, and the enhancement of biodiversity measures

    DEFF Research Database (Denmark)

    Real, Raimundo; Barbosa, A. Márcia; Bull, Joseph William

    2017-01-01

    differently to similar environmental conditions at different places or moments, so their distribution is, in principle, not completely predictable. We argue that this uncertainty exists, and warrants considering species distributions as analogous to coherent quantum objects, whose distributions are better...... biodiversity”. We show how conceptualizing species’ distributions in this way could help overcome important weaknesses in current biodiversity metrics, both in theory and by using a worked case study of mammal distributions in Spain over the last decade. We propose that considerable theoretical advances could...... eventually be gained through interdisciplinary collaboration between biogeographers and quantum physicists. [Biogeography; favorability; physics; predictability; probability; species occurrence; uncertainty; wavefunction....

  8. Local distribution of wall static pressure and heat transfer on a rough flat plate impinged by a slot air jet

    Science.gov (United States)

    Meda, Adimurthy; Katti, Vadiraj V.

    2017-08-01

    The present work experimentally investigates the local distribution of wall static pressure and the heat transfer coefficient on a rough flat plate impinged by a slot air jet. The experimental parameters include, nozzle-to-plate spacing (Z /D h = 0.5-10.0), axial distance from stagnation point ( x/D h ), size of detached rib ( b = 4-12 mm) and Reynolds number ( Re = 2500-20,000). The wall static pressure on the surface is recorded using a Pitot tube and a differential pressure transmitter. Infrared thermal imaging technique is used to capture the temperature distribution on the target surface. It is observed that, the maximum wall static pressure occurs at the stagnation point ( x/D h = 0) for all nozzle-to-plate spacing ( Z/D h ) and rib dimensions studied. Coefficient of wall static pressure ( C p ) decreases monotonically with x/D h . Sub atmospheric pressure is evident in the detached rib configurations for jet to plate spacing up to 6.0 for all ribs studied. Sub atmospheric region is stronger at Z/D h = 0.5 due to the fluid accelerating under the rib. As nozzle to plate spacing ( Z/D h ) increases, the sub-atmospheric region becomes weak and vanishes gradually. Reasonable enhancement in both C p as well as Nu is observed for the detached rib configuration. Enhancement is found to decrease with the increase in the rib width. The results of the study can be used in optimizing the cooling system design.

  9. Static spherically symmetric anisotropic fluid distribution in presence of electromagnetic field

    CERN Document Server

    Mukherjeea, B

    2003-01-01

    Einstein's field equations of general relativity corresponding to the anisotropic (principal stresses unequal) static fluid sphere in presence of electromagnetic field have been solved exactly. The integration constants are determined by matching the obtained solution with the Reissner-Nordstroem solution over the boundary. It has been found that the fluid model has non-negative expression for mass density and pressure. The mass density and stresses are everywhere regular and monotonically decreasing functions of the radial coordinate. (author)

  10. Applications of species distribution modeling to paleobiology

    DEFF Research Database (Denmark)

    Svenning, Jens-Christian; Fløjgaard, Camilla; Marske, Katharine Ann

    2011-01-01

    the role of Pleistocene glacial refugia in biogeography and evolution, especially in Europe, but also in many other regions. SDM-based approaches are also beginning to contribute to a suite of other research questions, such as historical constraints on current distributions and diversity patterns, the end......-Pleistocene megafaunal extinctions, past community assembly, human paleobiogeography, Holocene paleoecology, and even deep-time biogeography (notably, providing insights into biogeographic dynamics >400 million years ago). We discuss important assumptions and uncertainties that affect the SDM approach to paleobiology...

  11. A simple model for skewed species-lifetime distributions

    KAUST Repository

    Murase, Yohsuke

    2010-06-11

    A simple model of a biological community assembly is studied. Communities are assembled by successive migrations and extinctions of species. In the model, species are interacting with each other. The intensity of the interaction between each pair of species is denoted by an interaction coefficient. At each time step, a new species is introduced to the system with randomly assigned interaction coefficients. If the sum of the coefficients, which we call the fitness of a species, is negative, the species goes extinct. The species-lifetime distribution is found to be well characterized by a stretched exponential function with an exponent close to 1/2. This profile agrees not only with more realistic population dynamics models but also with fossil records. We also find that an age-independent and inversely diversity-dependent mortality, which is confirmed in the simulation, is a key mechanism accounting for the distribution. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

  12. Species Distribution modeling as a tool to unravel determinants of palm distribution in Thailand

    DEFF Research Database (Denmark)

    Tovaranonte, Jantrararuk; Barfod, Anders S.; Balslev, Henrik

    2011-01-01

    As a consequence of the decimation of the forest cover in Thailand from 50% to ca. 20 % since the 1950ies, it is difficult to gain insight in the drivers behind past, present and future distribution ranges of plant species. Species distribution modeling allows visualization of potential species...... distribution under specific sets of assumptions. In this study we used maximum entropy to map potential distributions of 103 species of palms for which more than 5 herbarium records exist. Palms constitute key-stone plant group from both an ecological, economical and conservation perspective. The models were...

  13. Static pressure and wall shear stress distributions in air flow in a seven wire-wrapped rod bundle

    OpenAIRE

    Fernandez y Fernandez, Elói; Carajilescov, Pedro

    2000-01-01

    An experimental investigation is performed in a turbulent flow in a seven wire-wrapped rod bundle, mounted in an open air facility. Static pressure distributions are measured on central and peripheral rods. By using a Preston tube, the wall shear stress profiles are experimentally obtained along the perimeter of the rods. The geometric parameters of the test section are P/D=1.20 and H/D=15. The measuring section is located at L/D=40 from the air inlet. It is observed that the dimensionless st...

  14. Metal tolerant species distribution and richness in and around the ...

    African Journals Online (AJOL)

    Metal tolerant species distribution and richness in and around the metal based industries: Possible candidates for phytoremediation. G.O. Anoliefo, B Ikhajiagbe, B.O. Okonokhua, B.O. Edegbai, D.C. Obasuyi ...

  15. Mistaking geography for biology: inferring processes from species distributions.

    Science.gov (United States)

    Warren, Dan L; Cardillo, Marcel; Rosauer, Dan F; Bolnick, Daniel I

    2014-10-01

    Over the past few decades, there has been a rapid proliferation of statistical methods that infer evolutionary and ecological processes from data on species distributions. These methods have led to considerable new insights, but they often fail to account for the effects of historical biogeography on present-day species distributions. Because the geography of speciation can lead to patterns of spatial and temporal autocorrelation in the distributions of species within a clade, this can result in misleading inferences about the importance of deterministic processes in generating spatial patterns of biodiversity. In this opinion article, we discuss ways in which patterns of species distributions driven by historical biogeography are often interpreted as evidence of particular evolutionary or ecological processes. We focus on three areas that are especially prone to such misinterpretations: community phylogenetics, environmental niche modelling, and analyses of beta diversity (compositional turnover of biodiversity). Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  16. Gridded Species Distribution: Global Amphibian Richness Grids, 2015 Release

    Data.gov (United States)

    National Aeronautics and Space Administration — The 2015 Release of the Global Amphibian Richness Grids data set of the Gridded Species Distribution collection are aggregations of the presence grids data for the...

  17. Gridded Species Distribution, Version 1: Global Amphibians Original Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Amphibians Original Grids of the Gridded Species Distribution, Version 1 are converted 1- kilometer grid cell data available in the Geographic Coordinate...

  18. Determination of horizontal and vertical distribution of tree species in ...

    African Journals Online (AJOL)

    Determination of horizontal and vertical distribution of tree species in Turkey via Shuttle Radar Topography Mission (SRTM) satellite data and geographic information system: the case of Crimean pine ( Pinus nigra )

  19. Species Composition, Relative Abundance and Distribution of the ...

    African Journals Online (AJOL)

    ... Composition, Relative Abundance and Distribution of the Avian Fauna of Entoto Natural ... A study on avian species composition, relative abundance, diversity and ... Eucalyptus plantation, soil erosion, deforestation, habitat fragmentation, ...

  20. Gridded Species Distribution, Version 1: Global Amphibians Family Richness Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Amphibians Family Richness Grids of the Gridded Species Distribution, Version 1 are aggregations of the presence grids data at the family level. They are...

  1. Gridded Species Distribution: Global Mammal Richness Grids, 2015 Release

    Data.gov (United States)

    National Aeronautics and Space Administration — The 2015 Release of the Global Mammal Richness Grids data set of the Gridded Species Distribution collection are aggregations of the presence grids data for the...

  2. Impacts of Species Misidentification on Species Distribution Modeling with Presence-Only Data

    Directory of Open Access Journals (Sweden)

    Hugo Costa

    2015-11-01

    Full Text Available Spatial records of species are commonly misidentified, which can change the predicted distribution of a species obtained from a species distribution model (SDM. Experiments were undertaken to predict the distribution of real and simulated species using MaxEnt and presence-only data “contaminated” with varying rates of misidentification error. Additionally, the difference between the niche of the target and contaminating species was varied. The results show that species misidentification errors may act to contract or expand the predicted distribution of a species while shifting the predicted distribution towards that of the contaminating species. Furthermore the magnitude of the effects was positively related to the ecological distance between the species’ niches and the size of the error rates. Critically, the magnitude of the effects was substantial even when using small error rates, smaller than common average rates reported in the literature, which may go unnoticed while using a standard evaluation method, such as the area under the receiver operating characteristic curve. Finally, the effects outlined were shown to impact negatively on practical applications that use SDMs to identify priority areas, commonly selected for various purposes such as management. The results highlight that species misidentification should not be neglected in species distribution modeling.

  3. Near term climate projections for invasive species distributions

    Science.gov (United States)

    Jarnevich, C.S.; Stohlgren, T.J.

    2009-01-01

    Climate change and invasive species pose important conservation issues separately, and should be examined together. We used existing long term climate datasets for the US to project potential climate change into the future at a finer spatial and temporal resolution than the climate change scenarios generally available. These fine scale projections, along with new species distribution modeling techniques to forecast the potential extent of invasive species, can provide useful information to aide conservation and invasive species management efforts. We created habitat suitability maps for Pueraria montana (kudzu) under current climatic conditions and potential average conditions up to 30 years in the future. We examined how the potential distribution of this species will be affected by changing climate, and the management implications associated with these changes. Our models indicated that P. montana may increase its distribution particularly in the Northeast with climate change and may decrease in other areas. ?? 2008 Springer Science+Business Media B.V.

  4. Dispersal ability determines the scaling properties of species abundance distributions

    DEFF Research Database (Denmark)

    Borda-De-Água, Luís; Whittaker, Robert James; Cardoso, Pedro

    2017-01-01

    Species abundance distributions (SAD) are central to the description of diversity and have played a major role in the development of theories of biodiversity and biogeography. However, most work on species abundance distributions has focused on one single spatial scale. Here we used data on arthr......Species abundance distributions (SAD) are central to the description of diversity and have played a major role in the development of theories of biodiversity and biogeography. However, most work on species abundance distributions has focused on one single spatial scale. Here we used data...... on arthropods to test predictions obtained with computer simulations on whether dispersal ability influences the rate of change of SADs as a function of sample size. To characterize the change of the shape of the SADs we use the moments of the distributions: the skewness and the raw moments. In agreement...... with computer simulations, low dispersal ability species generate a hump for intermediate abundance classes earlier than the distributions of high dispersal ability species. Importantly, when plotted as function of sample size, the raw moments of the SADs of arthropods have a power law pattern similar...

  5. Insecticide species sensitivity distributions: importance of test species selection and relevance to aquatic ecosystems

    NARCIS (Netherlands)

    Maltby, L.; Blake, N.; Brock, T.C.M.; Brink, van den P.J.

    2005-01-01

    Single-species acute toxicity data and (micro)mesocosm data were collated for 16 insecticides. These data were used to investigate the importance of test-species selection in constructing species sensitivity distributions (SSDs) and the ability of estimated hazardous concentrations (HCs) to protect

  6. Species distribution modelling for plant communities: Stacked single species or multivariate modelling approaches?

    Science.gov (United States)

    Emilie B. Henderson; Janet L. Ohmann; Matthew J. Gregory; Heather M. Roberts; Harold S.J. Zald

    2014-01-01

    Landscape management and conservation planning require maps of vegetation composition and structure over large regions. Species distribution models (SDMs) are often used for individual species, but projects mapping multiple species are rarer. We compare maps of plant community composition assembled by stacking results from many SDMs with multivariate maps constructed...

  7. Species diversity and community similarity in fluctuating environments: parametric approaches using species abundance distributions.

    Science.gov (United States)

    Sæther, Bernt-Erik; Engen, Steinar; Grøtan, Vidar

    2013-07-01

    Here we review recent advances in characterizing pattern of variation in community structure in space and time based on parametric approaches utilizing the full distribution of abundances of species rather than some summary indices. Assessment of biodiversity based on the structure of rank-abundance plots or simple species diversity indices, which describe properties of the sample of individuals, may reveal limited information about the underlying species abundance distribution of the community because the number of individuals counted are dependent on the sampling intensity. For instance, assuming Poisson sampling and an underlying lognormal species abundance distribution implies that observed abundances (counts) are a sample from a Poisson lognormal distribution. A convenient property of this distribution is that the estimate of σ(2) can be used as an inverse measure of species diversity in a community as well as the number of unobserved species can be estimated approximately without bias for unknown sampling intensities. If two communities can be described by a bivariate lognormal species abundance model, then the correlation between the log abundances of species in the two communities is an index of similarity that can be estimated without knowledge of sampling intensities using the bivariate Poisson lognormal distribution. This method is even applicable as an approximation when the abundance distribution deviates from the lognormal. An analysis of the interrelationship between the parameters of the lognormal species abundance distribution in communities of species from a wide variety of taxa shows that the canonical hypothesis of Preston in general, for a given number of species, gives far too large variances in the distribution of log abundances. A general feature in community dynamics is that a large component of the variance in the species abundance distribution is caused by heterogeneity among species in the population dynamics as well as environmental

  8. The Distribution, Feeding and Reproduction of Clarioid Species in ...

    African Journals Online (AJOL)

    The Distribution, Feeding and Reproduction of Clarioid Species in Epie Creek Floodplain of the Niger Delta, Nigeria. ... Members of the C (Clarioides) constituted 52.8% of the total number of Clarias species caught in the creek, swamp channel and lake. They were omnivorous feeding on fish, crustaceans, insects, detritus ...

  9. The Global Distribution and Drivers of Alien Bird Species Richness

    Science.gov (United States)

    Dyer, Ellie E.; Cassey, Phillip; Redding, David W.; Collen, Ben; Franks, Victoria; Gaston, Kevin J.; Jones, Kate E.; Kark, Salit; Orme, C. David L.; Blackburn, Tim M.

    2017-01-01

    Alien species are a major component of human-induced environmental change. Variation in the numbers of alien species found in different areas is likely to depend on a combination of anthropogenic and environmental factors, with anthropogenic factors affecting the number of species introduced to new locations, and when, and environmental factors influencing how many species are able to persist there. However, global spatial and temporal variation in the drivers of alien introduction and species richness remain poorly understood. Here, we analyse an extensive new database of alien birds to explore what determines the global distribution of alien species richness for an entire taxonomic class. We demonstrate that the locations of origin and introduction of alien birds, and their identities, were initially driven largely by European (mainly British) colonialism. However, recent introductions are a wider phenomenon, involving more species and countries, and driven in part by increasing economic activity. We find that, globally, alien bird species richness is currently highest at midlatitudes and is strongly determined by anthropogenic effects, most notably the number of species introduced (i.e., “colonisation pressure”). Nevertheless, environmental drivers are also important, with native and alien species richness being strongly and consistently positively associated. Our results demonstrate that colonisation pressure is key to understanding alien species richness, show that areas of high native species richness are not resistant to colonisation by alien species at the global scale, and emphasise the likely ongoing threats to global environments from introductions of species. PMID:28081142

  10. The Global Distribution and Drivers of Alien Bird Species Richness.

    Science.gov (United States)

    Dyer, Ellie E; Cassey, Phillip; Redding, David W; Collen, Ben; Franks, Victoria; Gaston, Kevin J; Jones, Kate E; Kark, Salit; Orme, C David L; Blackburn, Tim M

    2017-01-01

    Alien species are a major component of human-induced environmental change. Variation in the numbers of alien species found in different areas is likely to depend on a combination of anthropogenic and environmental factors, with anthropogenic factors affecting the number of species introduced to new locations, and when, and environmental factors influencing how many species are able to persist there. However, global spatial and temporal variation in the drivers of alien introduction and species richness remain poorly understood. Here, we analyse an extensive new database of alien birds to explore what determines the global distribution of alien species richness for an entire taxonomic class. We demonstrate that the locations of origin and introduction of alien birds, and their identities, were initially driven largely by European (mainly British) colonialism. However, recent introductions are a wider phenomenon, involving more species and countries, and driven in part by increasing economic activity. We find that, globally, alien bird species richness is currently highest at midlatitudes and is strongly determined by anthropogenic effects, most notably the number of species introduced (i.e., "colonisation pressure"). Nevertheless, environmental drivers are also important, with native and alien species richness being strongly and consistently positively associated. Our results demonstrate that colonisation pressure is key to understanding alien species richness, show that areas of high native species richness are not resistant to colonisation by alien species at the global scale, and emphasise the likely ongoing threats to global environments from introductions of species.

  11. Finfish Species distribution and seasonality in Odi River, Niger Delta ...

    African Journals Online (AJOL)

    Finfish Species distribution and seasonality in Odi River, Niger Delta, Nigeria. ... absent in rainy season and Aplocheilichthys kingii, Barbus aboinensis absent in the dry season. Fish caught and its seasonality in number did not show any significant difference. Key Words: Fish population, Distribution, Seasonality, Odi River ...

  12. Derivation of South African water quality guidelines for Roundup(®) using species sensitivity distribution.

    Science.gov (United States)

    Mensah, Paul K; Palmer, Caroline G; Muller, Wilhelmine J

    2013-10-01

    Glyphosate-based herbicides are among the leading products used in South Africa to control weeds and invading alien plant species. Although these herbicides ultimately find their way into aquatic ecosystems, South Africa has no water quality guideline based on indigenous species to protect the country's aquatic biota against these biocides. In this study, South African water quality guidelines (SAWQGs) for Roundup(®) based on species sensitivity distribution (SSD) using indigenous aquatic biota were developed. Short-term and long-term toxicity tests were conducted with eight different aquatic species belonging to five different taxonomic groups. Static non-renewal experimental methods were employed for short-term lethal tests (≤4 days), and static renewal for long-term sublethal tests (≥4 days ≤21 days). LC50 values for animal exposure and EC50 values for algae were calculated using probit analysis and linear regression of transformed herbicide concentration as natural logarithm data against percentage growth inhibition, respectively. No effect concentration (NEC) was determined based on the dynamic energy budget model, using survival data. The LC50, EC50 and NEC values were used to develop species sensitivity distribution (SSD) concentrations for Roundup(®). Based on the SSD concentrations, the short-term and long-term SAWQGs for Roundup(®) were derived as 0.250 (0.106-0.589) mg/L, and 0.002 (0.000-0.021) mg/L, respectively. These WQGs may be useful in protecting South African aquatic life against transient or long-term exposure to glyphosate-based chemicals as part of integrated water resources management. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Soil nutrients influence spatial distributions of tropical tree species.

    Science.gov (United States)

    John, Robert; Dalling, James W; Harms, Kyle E; Yavitt, Joseph B; Stallard, Robert F; Mirabello, Matthew; Hubbell, Stephen P; Valencia, Renato; Navarrete, Hugo; Vallejo, Martha; Foster, Robin B

    2007-01-16

    The importance of niche vs. neutral assembly mechanisms in structuring tropical tree communities remains an important unsettled question in community ecology [Bell G (2005) Ecology 86:1757-1770]. There is ample evidence that species distributions are determined by soils and habitat factors at landscape (Yasuni), and Panama (Barro Colorado Island). Using spatial distribution maps of >0.5 million individual trees of 1,400 species and 10 essential plant nutrients, we used Monte Carlo simulations of species distributions to test plant-soil associations against null expectations based on dispersal assembly. We found that the spatial distributions of 36-51% of tree species at these sites show strong associations to soil nutrient distributions. Neutral dispersal assembly cannot account for these plant-soil associations or the observed niche breadths of these species. These results indicate that belowground resource availability plays an important role in the assembly of tropical tree communities at local scales and provide the basis for future investigations on the mechanisms of resource competition among tropical tree species.

  14. Species Distributions, Quantum Theory, and the Enhancement of Biodiversity Measures.

    Science.gov (United States)

    Real, Raimundo; Barbosa, A Márcia; Bull, Joseph W

    2017-05-01

    Species distributions are typically represented by records of their observed occurrence at a given spatial and temporal scale. Such records are inevitably incomplete and contingent on the spatial-temporal circumstances under which the observations were made. Moreover, organisms may respond differently to similar environmental conditions at different places or moments, so their distribution is, in principle, not completely predictable. We argue that this uncertainty exists, and warrants considering species distributions as analogous to coherent quantum objects, whose distributions are better described by a wavefunction rather than by a set of locations. We use this to extend the existing concept of "dark diversity", which incorporates into biodiversity metrics those species that could, but which have not yet been observed to, inhabit a region-thereby developing the idea of "potential biodiversity". We show how conceptualizing species' distributions in this way could help overcome important weaknesses in current biodiversity metrics, both in theory and by using a worked case study of mammal distributions in Spain over the last decade. We propose that considerable theoretical advances could eventually be gained through interdisciplinary collaboration between biogeographers and quantum physicists. [Biogeography; favorability; physics; predictability; probability; species occurrence; uncertainty; wavefunction. © The Author(s) 2016. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Distribution and diversity of twelve Curcuma species in China.

    Science.gov (United States)

    Zhang, Lanyue; Wei, Jingwen; Yang, Zhiwen; Chen, Feng; Xian, Qiqiu; Su, Ping; Pan, Wanyi; Zhang, Kun; Zheng, Xi; Du, Zhiyun

    2018-02-01

    Genus Curcuma a wild species presents an important source of valuable characters for improving the cultivated Curcuma varieties. Based on the collected germplasms, herbariums, field surveys and other literatures, the ecogeographical diversity of Genus Curcuma and its potential distributions under the present and future climate are analysed by DIVA-GIS. The results indicate Genus Curcuma is distributed over 17 provinces in China, and particularly abundant in Guangxi and Guangdong provinces. The simulated current distributions are close to the actual distribution regions. In the future climate, the suitable areas for four Curcuma species will be extended, while for other three species the regions will be significantly decreased, and thus these valuable resources need protecting.

  16. Predicting fish species distribution in estuaries: Influence of species' ecology in model accuracy

    Science.gov (United States)

    França, Susana; Cabral, Henrique N.

    2016-10-01

    Current threats to biodiversity, combined with limited data availability, have made for species distribution models (SDMs) to be increasingly used due to their ability to predict species' potential distribution, by relating species occurrence with environmental estimates. Often used in ecology, conservation biology and environmental management, SDMs have been informing conservation strategies, and thus it is becoming crucial to understand how trustworthy their predictions are. Uncertainty in model predictions is expected, but knowing the origin of prediction errors may help reducing it. Indeed, uncertainty may be related not only with data quality and the modelling algorithm used, but also with species ecological characteristics. To investigate whether the performance of SDM's may vary with species' ecological characteristics, distribution models for 21 fish species occurring in estuaries from the Portuguese coast were examined. These models were built at two distinct spatial resolutions and seven environmental explanatory variables were used as predictors. SDMs' accuracy was assessed with the area under the curve (AUC) of receiver operating characteristics (ROC) plots, sensitivity and specificity. Relationships between each measure of accuracy and species ecological characteristics were then examined. SDMs of the fish species presented small differences between the considered scales, and predictors as latitude, temperature and salinity were often selected at both scales. Measures of model accuracy presented differences between species and scales, but generally higher accuracy was obtained at smaller spatial scales. Among the ecological traits tested, species feeding mode and estuarine use functional groups were the most influential on the performance of distribution models. Habitat tolerance (number of habitat types frequented), species abundance, body size and spawning period also showed some effect. This analyses will contribute to distinguish, based on species

  17. Theoretical perspectives on the statics and dynamics of species' borders in patchy environments.

    Science.gov (United States)

    Holt, Robert D; Barfield, Michael

    2011-10-01

    Understanding range limits is a fundamental problem in ecology and evolutionary biology. In 1963, Mayr argued that "contaminating" gene flow from central populations constrained adaptation in marginal populations, preventing range expansion, while in 1984, Bradshaw suggested that absence of genetic variation prevented species from occurring everywhere. Understanding stability of range boundaries requires unraveling the interplay of demography, gene flow, and evolution of populations in concrete landscape settings. We walk through a set of interrelated spatial scenarios that illustrate interesting complexities of this interplay. To motivate our individual-based model results, we consider a hypothetical zooplankter in a landscape of discrete water bodies coupled by dispersal. We examine how patterns of dispersal influence adaptation in sink habitats where conditions are outside the species' niche. The likelihood of observing niche evolution (and thus range expansion) over any given timescale depends on (1) the degree of initial maladaptation; (2) pattern (pulsed vs. continuous, uni- vs. bidirectional), timing (juvenile vs. adult), and rate of dispersal (and hence population size); (3) mutation rate; (4) sexuality; and (5) the degree of heterogeneity in the occupied range. We also show how the genetic architecture of polygenic adaptation is influenced by the interplay of selection and dispersal in heterogeneous landscapes.

  18. Diversity and distribution of cryptic species within the Mugil cephalus species complex in Vietnam.

    Science.gov (United States)

    Viet Tran, Thanh Thi; Ke Phan, Long; Durand, Jean-Dominique

    2017-07-01

    Mugil cephalus sensu lato is a globally distributed complex of cryptic species whose distribution range and evolutionary history remains largely unknown. In the North West (NW) Pacific three species have been identified genetically among fish described morphologically as M. cephalus. Their distribution ranges are largely parapatric and has been proposed to mirror different thermal preferences. To date, few samples have been analyzed from South China Sea, which limits inferences on the evolutionary history of the species complex. We sampled fish identified morphologically as M. cephalus along Vietnamese shores and characterized them using the sequence polymorphism of two mitochondrial genes, the cytochrome oxidase I and cytochrome b. This demonstrated that all three species described in the NW Pacific are present in both northern and southern Vietnamese waters. Although the difference in species abundance reflects those observed in the NW Pacific, no phylogeographic pattern was revealed. In addition, no population structure was observed whatever the species or the distribution range considered, which indicates a significant level of gene flow that maintains genetic homogeneity of the three species. It is also conceivable that each species experienced a recent population expansion from a single ancestral population. Finally we suggest that if the cold waters of the NW Pacific present a physiologic challenge leading to the almost parapatric distribution of the three species, then it is likely that the warm surface temperatures of the South China Sea negate this barrier.

  19. Multiple peaks of species abundance distributions induced by sparse interactions

    CERN Document Server

    Obuchi, Tomoyuki; Tokita, Kei

    2016-01-01

    We investigate the replicator dynamics with "sparse" symmetric interactions which represent specialist-specialist interactions in ecological communities. By considering a large self interaction $u$, we conduct a perturbative expansion which manifests that the nature of the interactions has a direct impact on the species abundance distribution. The central results are all species coexistence in a realistic range of the model parameters and that a certain discrete nature of the interactions induces multiple peaks in the species abundance distribution, providing the possibility of theoretically explaining multiple peaks observed in various field studies. To get more quantitative information, we also construct a non-perturbative theory which becomes exact on tree-like networks if all the species coexist, providing exact critical values of $u$ below which extinct species emerge. Numerical simulations in various different situations are conducted and they clarify the robustness of the presented mechanism of all spe...

  20. Predicting species distribution combining multi-scale drivers

    Directory of Open Access Journals (Sweden)

    Alice Fournier

    2017-10-01

    Full Text Available Species Distribution Models (SDMs are often used to predict the potential range of invasive species. Unfortunately, most studies do not evaluate variables relevance before selecting them to fit their models. Moreover, multiple variables such as climate and land use may drive species distribution at different spatial scales but most studies either use a single type of drivers, or combine multiple types without respecting their operating scale. We propose a three steps framework to overcome this limitation. First, use SDMs to select the most relevant climatic variables to predict a given species distribution, at continental scale. Then, characterize the species-habitat relationships, at a local scale, to produce species and area specific habitat filters. Finally, combine both information, each obtained at a relevant scale, to refine climatic predictions according to habitat suitability. We illustrate this framework with 14,794 Asian hornet (Vespa velutina nigrithorax records. We show that integrating multiple drivers, while still respecting their scale of effect, produced a potential range 55.9% smaller than that predicted using the climatic model alone, suggesting a systematic overestimation in many published predictions. This general framework illustrated by a well-documented invasive species is applicable to other taxa and scenarios of future climate and land-cover changes.

  1. Life history traits to predict biogeographic species distributions in bivalves

    Science.gov (United States)

    Montalto, V.; Rinaldi, A.; Sarà, G.

    2015-10-01

    Organismal fecundity ( F) and its relationship with body size (BS) are key factors in predicting species distribution under current and future scenarios of global change. A functional trait-based dynamic energy budget (FT-DEB) is proposed as a mechanistic approach to predict the variation of F and BS as function of environmental correlates using two marine bivalves as model species ( Mytilus galloprovincialis and Brachidontes pharaonis). Validation proof of model skill (i.e., degree of correspondence between model predictions and field observations) and stationarity (i.e., ability of a model generated from data collected at one place/time to predict processes at another place/time) was provided to test model performance in predicting the bivalve distribution throughout the 22 sites in the Central Mediterranean Sea under local conditions of food density and body temperature. Model skill and stationarity were tested through the estimate of commission (i.e., proportion of species' absences predicted present) and omission (i.e., proportion of presences predicted absent) errors of predictions by comparing mechanistic predicted vs. observed F and BS values throughout the study area extrapolated by lab experiments and literature search. The resulting relationship was reliable for both species, and body size and fecundity were highly correlated in M. galloprovincialis compared to B. pharaonis; FT-DEB showed correct predictions of presence in more than 75 % of sites, and the regression between BS predicted vs. observed was highly significant in both species. Whilst recognising the importance of biotic interactions in shaping the distribution of species, our FT-DEB approach provided reliable quantitative estimates of where our species had sufficient F to support local populations or suggesting reproductive failure. Mechanistically, estimating F and BS as key traits of species life history can also be addressed within a broader, scale-dependent context that surpasses the

  2. Recent distribution of Echinodermata species in Spitsbergen coastal waters

    Directory of Open Access Journals (Sweden)

    Deja Kajetan

    2016-12-01

    Full Text Available Thirty-two species of echinoderms from epibenthic sledges, dredges, scuba diving, and other samples (in total: 467 samples and c. 20 000 specimens from fjords and coastal waters off Spitsbergen were analysed between 1996 and 2014. The most numerous group of echinoderms in the coastal waters off Spitsbergen is brittle stars (78% of the total individuals. The echinoderms do not form any clear assemblages according to depth or distance from glacial sedimentation and substrate. Some species prefer hard bottom (Strongylocentrotus droebachiensis or water free from glacial suspensions (Ophiopholis aculeata. In contrast to the species listed above, we also found opportunistic species such as the starfish Urasterias lincki and the brittle star Ophiocten sericeum. These two species are distributed quite uniformly, regardless of the environmental factors. The majority of the species prefer a soft bottom below 200 m.

  3. Do stacked species distribution models reflect altitudinal diversity patterns?

    Directory of Open Access Journals (Sweden)

    Rubén G Mateo

    Full Text Available The objective of this study was to evaluate the performance of stacked species distribution models in predicting the alpha and gamma species diversity patterns of two important plant clades along elevation in the Andes. We modelled the distribution of the species in the Anthurium genus (53 species and the Bromeliaceae family (89 species using six modelling techniques. We combined all of the predictions for the same species in ensemble models based on two different criteria: the average of the rescaled predictions by all techniques and the average of the best techniques. The rescaled predictions were then reclassified into binary predictions (presence/absence. By stacking either the original predictions or binary predictions for both ensemble procedures, we obtained four different species richness models per taxa. The gamma and alpha diversity per elevation band (500 m was also computed. To evaluate the prediction abilities for the four predictions of species richness and gamma diversity, the models were compared with the real data along an elevation gradient that was independently compiled by specialists. Finally, we also tested whether our richness models performed better than a null model of altitudinal changes of diversity based on the literature. Stacking of the ensemble prediction of the individual species models generated richness models that proved to be well correlated with the observed alpha diversity richness patterns along elevation and with the gamma diversity derived from the literature. Overall, these models tend to overpredict species richness. The use of the ensemble predictions from the species models built with different techniques seems very promising for modelling of species assemblages. Stacking of the binary models reduced the over-prediction, although more research is needed. The randomisation test proved to be a promising method for testing the performance of the stacked models, but other implementations may still be

  4. Do stacked species distribution models reflect altitudinal diversity patterns?

    Science.gov (United States)

    Mateo, Rubén G; Felicísimo, Ángel M; Pottier, Julien; Guisan, Antoine; Muñoz, Jesús

    2012-01-01

    The objective of this study was to evaluate the performance of stacked species distribution models in predicting the alpha and gamma species diversity patterns of two important plant clades along elevation in the Andes. We modelled the distribution of the species in the Anthurium genus (53 species) and the Bromeliaceae family (89 species) using six modelling techniques. We combined all of the predictions for the same species in ensemble models based on two different criteria: the average of the rescaled predictions by all techniques and the average of the best techniques. The rescaled predictions were then reclassified into binary predictions (presence/absence). By stacking either the original predictions or binary predictions for both ensemble procedures, we obtained four different species richness models per taxa. The gamma and alpha diversity per elevation band (500 m) was also computed. To evaluate the prediction abilities for the four predictions of species richness and gamma diversity, the models were compared with the real data along an elevation gradient that was independently compiled by specialists. Finally, we also tested whether our richness models performed better than a null model of altitudinal changes of diversity based on the literature. Stacking of the ensemble prediction of the individual species models generated richness models that proved to be well correlated with the observed alpha diversity richness patterns along elevation and with the gamma diversity derived from the literature. Overall, these models tend to overpredict species richness. The use of the ensemble predictions from the species models built with different techniques seems very promising for modelling of species assemblages. Stacking of the binary models reduced the over-prediction, although more research is needed. The randomisation test proved to be a promising method for testing the performance of the stacked models, but other implementations may still be developed.

  5. A Linear Algebra Framework for Static High Performance Fortran Code Distribution

    Directory of Open Access Journals (Sweden)

    Corinne Ancourt

    1997-01-01

    Full Text Available High Performance Fortran (HPF was developed to support data parallel programming for single-instruction multiple-data (SIMD and multiple-instruction multiple-data (MIMD machines with distributed memory. The programmer is provided a familiar uniform logical address space and specifies the data distribution by directives. The compiler then exploits these directives to allocate arrays in the local memories, to assign computations to elementary processors, and to migrate data between processors when required. We show here that linear algebra is a powerful framework to encode HPF directives and to synthesize distributed code with space-efficient array allocation, tight loop bounds, and vectorized communications for INDEPENDENT loops. The generated code includes traditional optimizations such as guard elimination, message vectorization and aggregation, and overlap analysis. The systematic use of an affine framework makes it possible to prove the compilation scheme correct.

  6. Distribution of static pressure of seeds in a shallow model silo

    Science.gov (United States)

    Horabik, Józef; Molenda, Marek

    2017-04-01

    The influence of the filling method, the seed size and the aspect ratio on the radial distribution of the vertical pressure on the floor of a shallow model silo and radial distribution of tangent stress within the material was investigated. Three filling methods were applied: central, circumferential and distributed. Seeds of five varieties were used: horse bean, field pea, wheat, vetch, and rapeseed. Vertical pressure on the floor of a shallow bin was found to be influenced by the filling method and the seed size and aspect ratio. A significant dip of vertical pressure in the middle radial location was observed in all tests, except two: central and circumferential filling of rapeseed. Wall friction was mobilized in the highest degree in the case of the central filling, while the lowest was mobilization of friction in the case of the circumferential filling.

  7. Geographical distribution of invasive insect species in Albania

    Directory of Open Access Journals (Sweden)

    KEÇI Erjola

    2012-09-01

    Full Text Available Albania, just like every other country in the world, has been threatened by invasive species for years now. Although most of the invasive species have not a big impact in environment and economy of the country where they are introduced, some “good” introduced species at the beginning can turn to harmful invaders. Unlike most other pollutants, the effects of biological invaders are likely to increase through time as existing populations expand, even ifnew introductions are halted. Physical and geographical traits of Albania, such as habitat fragmentation, long coastline withmany harbors, facilitate the successful introduction of harmful invasive insect species. The aim of our work was to study thegeographical distribution, time and sites of introduction of invasive insects in Albania. Sampling expeditions were organized in13 cities belonging to 4 regions (south, north, west, east region in Albania. During 2009-2010 we collected 478 individualsbelonging to 5 insects orders, 15 families and 21 species. Individuals collected are classified as below: oder Lepidoptera, 5families, 8 species; order Coleoptera, 4 families, 6 species; order Homoptera, 3 families, 4 species; order Diptera, 2 families, 2species; order Prostigmata, 1 family, 1 specie. Many of these invasive insects are found from us in territories far away fromintroduction site.

  8. Species distribution models of tropical deep-sea snappers.

    Directory of Open Access Journals (Sweden)

    Céline Gomez

    Full Text Available Deep-sea fisheries provide an important source of protein to Pacific Island countries and territories that are highly dependent on fish for food security. However, spatial management of these deep-sea habitats is hindered by insufficient data. We developed species distribution models using spatially limited presence data for the main harvested species in the Western Central Pacific Ocean. We used bathymetric and water temperature data to develop presence-only species distribution models for the commercially exploited deep-sea snappers Etelis Cuvier 1828, Pristipomoides Valenciennes 1830, and Aphareus Cuvier 1830. We evaluated the performance of four different algorithms (CTA, GLM, MARS, and MAXENT within the BIOMOD framework to obtain an ensemble of predicted distributions. We projected these predictions across the Western Central Pacific Ocean to produce maps of potential deep-sea snapper distributions in 32 countries and territories. Depth was consistently the best predictor of presence for all species groups across all models. Bathymetric slope was consistently the poorest predictor. Temperature at depth was a good predictor of presence for GLM only. Model precision was highest for MAXENT and CTA. There were strong regional patterns in predicted distribution of suitable habitat, with the largest areas of suitable habitat (> 35% of the Exclusive Economic Zone predicted in seven South Pacific countries and territories (Fiji, Matthew & Hunter, Nauru, New Caledonia, Tonga, Vanuatu and Wallis & Futuna. Predicted habitat also varied among species, with the proportion of predicted habitat highest for Aphareus and lowest for Etelis. Despite data paucity, the relationship between deep-sea snapper presence and their environments was sufficiently strong to predict their distribution across a large area of the Pacific Ocean. Our results therefore provide a strong baseline for designing monitoring programs that balance resource exploitation and

  9. Spatial factor analysis: a new tool for estimating joint species distributions and correlations in species range

    DEFF Research Database (Denmark)

    Thorson, James T.; Scheuerell, Mark D.; Shelton, Andrew O.

    2015-01-01

    be imprecise for species with low densities or few observations. Additionally, simple geostatistical methods fail to account for correlations in distribution among species and generally estimate such cross-correlations as a post hoc exercise. 2. We therefore present spatial factor analysis (SFA), a spatial...

  10. Biotic Interactions Shape the Ecological Distributions of Staphylococcus Species.

    Science.gov (United States)

    Kastman, Erik K; Kamelamela, Noelani; Norville, Josh W; Cosetta, Casey M; Dutton, Rachel J; Wolfe, Benjamin E

    2016-10-18

    Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes. Decades of culture-based studies and more recent metagenomic studies have demonstrated that bacterial species in agriculture, medicine, industry, and nature are unevenly distributed across time and space. The ecological processes and molecular mechanisms that shape these distributions are not well understood because it is challenging to connect in situ patterns of diversity with mechanistic in vitro studies in the laboratory. Using tractable cheese rind biofilms and a focus on coagulase-negative staphylococcus (CNS

  11. Exploring Verbal, Visual and Schematic Learners' Static and Dynamic Mental Images of Scientific Species and Processes in Relation to Their Spatial Ability

    Science.gov (United States)

    Al-Balushi, Sulaiman M.; Coll, Richard Kevin

    2013-01-01

    The current study compared different learners' static and dynamic mental images of unseen scientific species and processes in relation to their spatial ability. Learners were classified into verbal, visual and schematic. Dynamic images were classified into: appearing/disappearing, linear-movement, and rotation. Two types of scientific entities and…

  12. Odonata of maharashtra, India with notes on species distribution.

    Science.gov (United States)

    Tiple, Ashish D; Koparde, Pankaj

    2015-01-01

    Odonata are freshwater insects spread world-wide. Tropical areas are high Odonata diversity areas. However, there has not been accumulation of extensive baseline data on spatial distribution of these insects from such places. Maharashtra, the third largest state of India, harbors a variety of land-use and occupies six biogeographic provinces. We carried out Odonata surveys in Maharashtra during 2006-2014. Compilation of all these studies along with other authenticated records resulted in a checklist of 134 species of Odonata belonging to 70 genera representing 11 families. The highest numbers of species were recorded from the Libellulidae (48 species) and Gomphidae (22 species) families. A previous study had reported 99 species of Odonata from the Maharashtra state considering records from early 1900's to 2012. Our observations across the state add 33 species to this list. Maharashtra forms a unique source of Odonata diversity and our observations support the importance of this region in providing valuable habitats for Odonata. Here, we discuss several of the new records, how global surveys might help fill the local gap in species distributions, how secondary data deposited through crowd-sourcing can help and what it offers to conservation. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  13. How can model comparison help improving species distribution models?

    Directory of Open Access Journals (Sweden)

    Emmanuel Stephan Gritti

    Full Text Available Today, more than ever, robust projections of potential species range shifts are needed to anticipate and mitigate the impacts of climate change on biodiversity and ecosystem services. Such projections are so far provided almost exclusively by correlative species distribution models (correlative SDMs. However, concerns regarding the reliability of their predictive power are growing and several authors call for the development of process-based SDMs. Still, each of these methods presents strengths and weakness which have to be estimated if they are to be reliably used by decision makers. In this study we compare projections of three different SDMs (STASH, LPJ and PHENOFIT that lie in the continuum between correlative models and process-based models for the current distribution of three major European tree species, Fagussylvatica L., Quercusrobur L. and Pinussylvestris L. We compare the consistency of the model simulations using an innovative comparison map profile method, integrating local and multi-scale comparisons. The three models simulate relatively accurately the current distribution of the three species. The process-based model performs almost as well as the correlative model, although parameters of the former are not fitted to the observed species distributions. According to our simulations, species range limits are triggered, at the European scale, by establishment and survival through processes primarily related to phenology and resistance to abiotic stress rather than to growth efficiency. The accuracy of projections of the hybrid and process-based model could however be improved by integrating a more realistic representation of the species resistance to water stress for instance, advocating for pursuing efforts to understand and formulate explicitly the impact of climatic conditions and variations on these processes.

  14. Tardigrades of Alaska: distribution patterns, diversity and species richness

    Directory of Open Access Journals (Sweden)

    Carl Johansson

    2013-05-01

    Full Text Available During the summer of 2010, a biotic survey of tardigrades was conducted along a latitudinal transect in central Alaska from the Kenai Peninsula, via Fairbanks and the Arctic Circle to the coastal plain. Work was centred at the Toolik and Bonanza Creek Long Term Ecological Research Network sites and supplemented by opportunistic collections from the Kenai Peninsula and Anchorage areas. The 235 samples collected at 20 sites over 10 degrees of latitude yielded 1463 tardigrades representing two classes, three orders, 10 families, 23 genera and 73 species from 142 positive samples. A total of 50 species are new to Alaska, increasing the state's known species richness to 84. Several environmental metrics, such as pH, substrate, elevation, location and habitat were measured, recorded and analysed along the latitudinal gradient. Contrary to expectations, pH did not appear to be a predictor of tardigrade abundance or distribution. Density and species richness were relatively consistent across sites. However, the assemblages were highly variable within and between sites at only 14–20% similarity. We detected no correlation between species diversity and latitudinal or environmental gradients, though this may be affected by a high (59.9% occurrence of single-species samples (containing individuals of only one species. Estimates of species richness were calculated for Alaska (118 and the Arctic (172. Our efforts increased the number of known species in Alaska to 84, and those results led us to question the validity of the estimate numbers.

  15. Causality of the relationship between geographic distribution and species abundance

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Rahbek, Carsten

    2010-01-01

    The positive relationship between a species' geographic distribution and its abundance is one of ecology's most well-documented patterns, yet the causes behind this relationship remain unclear. Although many hypotheses have been proposed to account for distribution-abundance relationships none have...... differences in terminology and ecological point of view. Realizing and accounting for these differences facilitates integration, so that the relative contributions of each mechanism may be evaluated. Here, we review all the mechanisms that have been proposed to account for distribution-abundance relationships...

  16. Species diversity, distribution and predilection sites of ticks (Acarina ...

    African Journals Online (AJOL)

    This result will help to fill the gap in the knowledge of the species diversity, distribution and predilection sites of ticks introduced into the study-area. It may also stimulate further research interest in the ecology of disease vectors as well as provide evidence-based decision for the surveillance of potential TBID transmission in ...

  17. Fish species composition, size structure and distribution in non ...

    African Journals Online (AJOL)

    Fish diversity studies in littoral non-trawlable areas of Lake Victoria (Tanzania) were undertaken during six systematic surveys (November 2000 to December 2002). Information on fish species composition, size structure as well as spatial and temporal distribution was generated from gill-netting, beach-seining and electric ...

  18. Distribution of veld rat sibling species Aethomys chrysophilus and ...

    African Journals Online (AJOL)

    Sibling species Aethomys chrysophilus (de Winton) and Aethomys ineptus Thomas and Wroughton are indistinguishable in external morphology. Although their combined geographic range extends over a large area of southern Africa, their respective distributions are uncertain. We have assembled a database that includes ...

  19. Sparse Distribution Pattern Of Some Plant Species In Two ...

    African Journals Online (AJOL)

    This study analysed species diversity and distribution patterns on two afromontane rain forests of the eastern Arc Mountains of Tanzania in the west Usambaras and Ulugurus to assess any possible threats to biodiversity conservation in this region. A hundred sample plots (0.02 ha) were established on each of the two ...

  20. Fish species composition and distribution in an urban perturbed ...

    African Journals Online (AJOL)

    The abundance and distribution of fish species in River Orogodo were studied. Sampling was conducted in three stations of the river, from January 2006 to December 2007. The river was demarcated in accordance with local hydrographic conditions as well as intensity of anthropogenic activities along the stretch.

  1. Determination of horizontal and vertical distribution of tree species in ...

    African Journals Online (AJOL)

    Yomi

    2012-01-24

    Jan 24, 2012 ... using a digital elevation model obtained from Shuttle Radar Topography Mission (SRTM) satellite data and 1/100,000 scale Forest Information System database, horizontal and vertical distribution of Pinus nigra (Crimean Pine), which is geographically the largest spread needled tree species in Turkey, (to.

  2. Equilibrium of global amphibian species distributions with climate

    DEFF Research Database (Denmark)

    Munguí­a, Mariana; Rahbek, Carsten; Rangel, Thiago F.

    2012-01-01

    of their potential distributions than species in the Nearctic, Madagascar, and Australasia. We acknowledge that our models underestimate non equilibrium, and discuss potential reasons for the observed patterns. From a modeling perspective our results support the view that at global scale bioclimatic envelope models...

  3. Distribution of two post-larvae species of commercial prawns ...

    African Journals Online (AJOL)

    The white prawn, Fenneropenaeus indicus, and the tiger prawn, Penaeus monodon, are of great commercial importance, and they are extensively farmed along the eastern coast of India. Post-larvae of these species coexist in great abundance in estuaries along the Bay of Bengal. In this investigation, field distribution, ...

  4. The distribution of Monechma (Acanthaceae species in southern Africa

    Directory of Open Access Journals (Sweden)

    Joan Munday

    1983-12-01

    Full Text Available The distribution of 19 species of Monechma in southern Africa is given and the manner in which their occurrence is related to rainfall is discussed. The possibility of a centre of speciation lying in south-west Namibia/South West Africa is considered.

  5. VEGETATIVE MORPHOLOGY FOR SPECIES IDENTIFICATION OF TROPICAL TREES: FAMILY DISTRIBUTION

    Directory of Open Access Journals (Sweden)

    Peter Hargreaves

    2006-03-01

    Full Text Available Tree specimens from the ESAL herbarium of the Universidade Federal de Lavras, Minas Gerais, Brazil, were describedby vegetative characteristics using CARipé, a Microsoft Access database application specially developed for this study. Only onespecimen per species was usually described. Thus, 2 observers described 567 herbarium species as a base to test methods ofidentification as part of a larger study. The present work formed part of that study and provides information on the distribution of22 vegetative characters among 16 families having 10 or more species described. The characters are discussed. The study foundmarked differences, even discontinuities, of distributions of characters between those families. Therefore it should be possible toincorporate phylogenetic relationships into the identification process.

  6. Distribution of metal and adsorbed guest species in zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Chmelka, B.F.

    1989-12-01

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes {sup 129}Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of {sup 129}Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, {sup 129}Xe NMR is insensitive to fine structural details at room temperature.

  7. Species-free species distribution models describe macroecological properties of protected area networks.

    Science.gov (United States)

    Robinson, Jason L; Fordyce, James A

    2017-01-01

    Among the greatest challenges facing the conservation of plants and animal species in protected areas are threats from a rapidly changing climate. An altered climate creates both challenges and opportunities for improving the management of protected areas in networks. Increasingly, quantitative tools like species distribution modeling are used to assess the performance of protected areas and predict potential responses to changing climates for groups of species, within a predictive framework. At larger geographic domains and scales, protected area network units have spatial geoclimatic properties that can be described in the gap analysis typically used to measure or aggregate the geographic distributions of species (stacked species distribution models, or S-SDM). We extend the use of species distribution modeling techniques in order to model the climate envelope (or "footprint") of individual protected areas within a network of protected areas distributed across the 48 conterminous United States and managed by the US National Park System. In our approach we treat each protected area as the geographic range of a hypothetical endemic species, then use MaxEnt and 5 uncorrelated BioClim variables to model the geographic distribution of the climatic envelope associated with each protected area unit (modeling the geographic area of park units as the range of a species). We describe the individual and aggregated climate envelopes predicted by a large network of 163 protected areas and briefly illustrate how macroecological measures of geodiversity can be derived from our analysis of the landscape ecological context of protected areas. To estimate trajectories of change in the temporal distribution of climatic features within a protected area network, we projected the climate envelopes of protected areas in current conditions onto a dataset of predicted future climatic conditions. Our results suggest that the climate envelopes of some parks may be locally unique or have

  8. Cartograms tool to represent spatial uncertainty in species distribution

    Directory of Open Access Journals (Sweden)

    Duccio Rocchini

    2017-02-01

    Full Text Available Species distribution models have become an important tool for biodiversity monitoring. Like all statistical modelling techniques developed based on field data, they are prone to uncertainty due to bias in the sampling (e.g. identification, effort, detectability. In this study, we explicitly quantify and map the uncertainty derived from sampling effort bias. With that aim, we extracted data from the widely used GBIF dataset to map this semantic bias using cartograms.

  9. The Combined Use of Correlative and Mechanistic Species Distribution Models Benefits Low Conservation Status Species.

    Directory of Open Access Journals (Sweden)

    Thibaud Rougier

    Full Text Available Species can respond to climate change by tracking appropriate environmental conditions in space, resulting in a range shift. Species Distribution Models (SDMs can help forecast such range shift responses. For few species, both correlative and mechanistic SDMs were built, but allis shad (Alosa alosa, an endangered anadromous fish species, is one of them. The main purpose of this study was to provide a framework for joint analyses of correlative and mechanistic SDMs projections in order to strengthen conservation measures for species of conservation concern. Guidelines for joint representation and subsequent interpretation of models outputs were defined and applied. The present joint analysis was based on the novel mechanistic model GR3D (Global Repositioning Dynamics of Diadromous fish Distribution which was parameterized on allis shad and then used to predict its future distribution along the European Atlantic coast under different climate change scenarios (RCP 4.5 and RCP 8.5. We then used a correlative SDM for this species to forecast its distribution across the same geographic area and under the same climate change scenarios. First, projections from correlative and mechanistic models provided congruent trends in probability of habitat suitability and population dynamics. This agreement was preferentially interpreted as referring to the species vulnerability to climate change. Climate change could not be accordingly listed as a major threat for allis shad. The congruence in predicted range limits between SDMs projections was the next point of interest. The difference, when noticed, required to deepen our understanding of the niche modelled by each approach. In this respect, the relative position of the northern range limit between the two methods strongly suggested here that a key biological process related to intraspecific variability was potentially lacking in the mechanistic SDM. Based on our knowledge, we hypothesized that local

  10. Mechanisms controlling the distribution of two invasive Bromus species

    Directory of Open Access Journals (Sweden)

    Olga Bykova

    2014-03-01

    Full Text Available In order to predict future range shifts for invasive species it is important to explore their ability to acclimate to the new environment and understand physiological and reproductive constraints controlling their distribution. My dissertation studied mechanisms by which temperature may affect the distribution of two aggressive plant invaders in North America, Bromus tectorum and Bromus rubens. I first evaluated winter freezing tolerance of Bromus species and demonstrated that the mechanism explaining their distinct northern range limits is different acquisition time of freezing tolerance. While B. rubens has a slower rate of freezing acclimation that leads to intolerance of sudden, late-autumn drops in temperature below -12°C, B. tectorum rapidly hardens and so is not impacted by the sudden onset of severe late-autumn cold. In addition, the analysis of male reproductive development and seed production showed that neither species produces seed at or above 36°C, due to complete pollen sterility, which might trigger climate-mediated range contractions at B. tectorum and B. rubens southern margins. Finally, a detailed gas-exchange analysis combined with biochemical modelling demonstrated that both species acclimate to a broad range of temperatures and photosynthetic response to temperature does not explain their current range separation.

  11. Drought tolerance of tropical tree species : functional traits, trade-offs and species distribution

    NARCIS (Netherlands)

    Markesteijn, L.

    2010-01-01

    KEY-WORDS: Bolivia, drought tolerance, shade tolerance, functional traits, trade-offs, ecophysiology, species distribution Tropical forests occur under rainfall regimes that vary greatly in the rainfall pattern and frequency and intensity of drought. Consequently water availability is one of the

  12. Solar system formation and the distribution of volatile species

    Science.gov (United States)

    Lunine, Jonathan I.

    1994-01-01

    To understand how the solar system formed we must understand the compositional distribution of the current system. Volatile species are particularly important in that their stability as condensed phases is limited in temperature-pressure space, and hence variations in their distribution at present potentially contain an imprint of processes by which temperature and pressure varied in the solar nebula. In this talk we restrict ourselves to species more volatile than water ice, and address issues related to processes in the outer solar system and the formation of bodies there; others in this conference will cover volatile species relevant to inner solar system processes. Study of the outer solar system is relevant both to understanding the interface between the solar nebula and the progenitor giant molecular cloud (since the chemical links to present-day observables in molecular clouds are species like methane, carbon monoxide, etc.), as well as the origin of terrestrial planet atmospheres and oceans (the latter to be covered by Owen). The wealth of compositional information on outer solar system bodies which has become available from spacecraft and ground-based observations challenges traditional simplistic views of the composition and hence dynamics of the solar nebula. The basic assumption of thermochemical equilibrium, promulgated in the 1950's, in which methane and ammonia dominate nitrogen- and carbon-bearing species, is demonstrably incorrect on both observational and theoretical grounds. However, the kinetic inhibition model which replaced it, in which carbon monoxide and molecular nitrogen dominate a nebula which is fully mixed and hence cycles outer solar system gases through a hot, chemically active zone near the disk center, is not supported either by observations. Instead, a picture of the outer solar system emerges in which the gas and grains are a mixture of relatively unaltered, or modestly altered, molecular cloud material, along with a fraction

  13. The roles of competition and habitat in the dynamics of populations and species distributions.

    Science.gov (United States)

    Yackulic, Charles B; Reid, Janice; Nichols, James D; Hines, James E; Davis, Raymond; Forsman, Eric

    2014-02-01

    The role of competition in structuring biotic communities at fine spatial scales is well known from detailed process-based studies. Our understanding of competition's importance at broader scales is less resolved and mainly based on static species distribution maps. Here, we bridge this gap by examining the joint occupancy dynamics of an invading species (Barred Owl, Strix varia) and a resident species (Northern Spotted Owl, Strix occidentalis caurina) in a 1000-km study area over a 22-year period. Past studies of these competitors have focused on the dynamics of one species at a time, hindering efforts to parse out the roles of habitat and competition and to forecast the future of the resident species. In addition, while these studies accounted for the imperfect detection of the focal species, no multi-season analysis of these species has accounted for the imperfect detection of the secondary species, potentially biasing inference. We analyzed survey data using models that combine the general multistate-multi-season occupancy modeling framework with autologistic modeling, allowing us to account for important aspects of our study system. We found that local extinction probability increases for each species when the other is present; however, the effect of the invader on the resident is greater. Although the species prefer different habitats, these habitats are highly correlated at the patch scale, and the impacts of invader on the resident are greatest in patches that would otherwise be optimal. As a consequence, competition leads to a weaker relationship between habitat and Northern Spotted Owl occupancy. Colonization and extinction rates of the invader are closely related to neighborhood occupancy, and over the first half of the study the availability of colonists limited the rate of population growth. Competition is likely to exclude the resident species, both through its immediate effects on local extinction and by indirectly lowering colonization rates as

  14. Effects of urbanization on carnivore species distribution and richness

    Science.gov (United States)

    Ordenana, Miguel A.; Crooks, Kevin R.; Boydston, Erin E.; Fisher, Robert N.; Lyren, Lisa M.; Siudyla, Shalene; Haas, Christopher D.; Harris, Sierra; Hathaway, Stacie A.; Turschak, Greta M.; Miles, A. Keith; Van Vuren, Dirk H.

    2010-01-01

    Urban development can have multiple effects on mammalian carnivore communities. We conducted a meta-analysis of 7,929 photographs from 217 localities in 11 camera-trap studies across coastal southern California to describe habitat use and determine the effects of urban proximity (distance to urban edge) and intensity (percentage of area urbanized) on carnivore occurrence and species richness in natural habitats close to the urban boundary. Coyotes (Canis latrans) and bobcats (Lynx rufus) were distributed widely across the region. Domestic dogs (Canis lupus familiaris), striped skunks (Mephitis mephitis), raccoons (Procyon lotor), gray foxes (Urocyon cinereoargenteus), mountain lions (Puma concolor), and Virginia opossums (Didelphis virginiana) were detected less frequently, and long-tailed weasels (Mustela frenata), American badgers (Taxidea taxus), western spotted skunks (Spilogale gracilis), and domestic cats (Felis catus) were detected rarely. Habitat use generally reflected availability for most species. Coyote and raccoon occurrence increased with both proximity to and intensity of urbanization, whereas bobcat, gray fox, and mountain lion occurrence decreased with urban proximity and intensity. Domestic dogs and Virginia opossums exhibited positive and weak negative relationships, respectively, with urban intensity but were unaffected by urban proximity. Striped skunk occurrence increased with urban proximity but decreased with urban intensity. Native species richness was negatively associated with urban intensity but not urban proximity, probably because of the stronger negative response of individual species to urban intensity.

  15. Projecting future expansion of invasive species: comparing and improving methodologies for species distribution modeling.

    Science.gov (United States)

    Mainali, Kumar P; Warren, Dan L; Dhileepan, Kunjithapatham; McConnachie, Andrew; Strathie, Lorraine; Hassan, Gul; Karki, Debendra; Shrestha, Bharat B; Parmesan, Camille

    2015-12-01

    Modeling the distributions of species, especially of invasive species in non-native ranges, involves multiple challenges. Here, we developed some novel approaches to species distribution modeling aimed at reducing the influences of such challenges and improving the realism of projections. We estimated species-environment relationships for Parthenium hysterophorus L. (Asteraceae) with four modeling methods run with multiple scenarios of (i) sources of occurrences and geographically isolated background ranges for absences, (ii) approaches to drawing background (absence) points, and (iii) alternate sets of predictor variables. We further tested various quantitative metrics of model evaluation against biological insight. Model projections were very sensitive to the choice of training dataset. Model accuracy was much improved using a global dataset for model training, rather than restricting data input to the species' native range. AUC score was a poor metric for model evaluation and, if used alone, was not a useful criterion for assessing model performance. Projections away from the sampled space (i.e., into areas of potential future invasion) were very different depending on the modeling methods used, raising questions about the reliability of ensemble projections. Generalized linear models gave very unrealistic projections far away from the training region. Models that efficiently fit the dominant pattern, but exclude highly local patterns in the dataset and capture interactions as they appear in data (e.g., boosted regression trees), improved generalization of the models. Biological knowledge of the species and its distribution was important in refining choices about the best set of projections. A post hoc test conducted on a new Parthenium dataset from Nepal validated excellent predictive performance of our 'best' model. We showed that vast stretches of currently uninvaded geographic areas on multiple continents harbor highly suitable habitats for parthenium

  16. Distribution of Plasmids in Distinct Leptospira Pathogenic Species.

    Science.gov (United States)

    Wang, Yanzhuo; Zhuang, Xuran; Zhong, Yi; Zhang, Cuicai; Zhang, Yan; Zeng, Lingbing; Zhu, Yongzhang; He, Ping; Dong, Ke; Pal, Utpal; Guo, Xiaokui; Qin, Jinhong

    2015-11-01

    Leptospirosis, caused by pathogenic Leptospira, is a worldwide zoonotic infection. The genus Leptospira includes at least 21 species clustered into three groups--pathogens, non-pathogens, and intermediates--based on 16S rRNA phylogeny. Research on Leptospira is difficult due to slow growth and poor transformability of the pathogens. Recent identification of extrachromosomal elements besides the two chromosomes in L. interrogans has provided new insight into genome complexity of the genus Leptospira. The large size, low copy number, and high similarity of the sequence of these extrachromosomal elements with the chromosomes present challenges in isolating and detecting them without careful genome assembly. In this study, two extrachromosomal elements were identified in L. borgpetersenii serovar Ballum strain 56604 through whole genome assembly combined with S1 nuclease digestion following pulsed-field gel electrophoresis (S1-PFGE) analysis. Further, extrachromosomal elements in additional 15 Chinese epidemic strains of Leptospira, comprising L. borgpetersenii, L. weilii, and L. interrogans, were successfully separated and identified, independent of genome sequence data. Southern blot hybridization with extrachromosomal element-specific probes, designated as lcp1, lcp2 and lcp3-rep, further confirmed their occurrences as extrachromosomal elements. In total, 24 plasmids were detected in 13 out of 15 tested strains, among which 11 can hybridize with the lcp1-rep probe and 11 with the lcp2-rep probe, whereas two can hybridize with the lcp3-rep probe. None of them are likely to be species-specific. Blastp search of the lcp1, lcp2, and lcp3-rep genes with a nonredundant protein database of Leptospira species genomes showed that their homologous sequences are widely distributed among clades of pathogens but not non-pathogens or intermediates. These results suggest that the plasmids are widely distributed in Leptospira species, and further elucidation of their biological

  17. Predicting the past distribution of species climatic niches

    DEFF Research Database (Denmark)

    Nogues, David Bravo

    2009-01-01

    Predicting past distributions of species climatic niches, hindcasting, by using climate envelope models (CEMs) is emerging as an exciting research area. CEMs are used to examine veiled evolutionary questions about extinctions, locations of past refugia and migration pathways, or to propose...... the theoretical assumptions behind niche modelling and using inadequate methods for hindcasting CEMs may well entail a cascade of errors and naïve ecological and evolutionary inferences. We should also push integrative research lines linking macroecology, physiology, population biology, palaeontology......, evolutionary biology and CEMs for a better understanding of niche dynamics across space and time....

  18. More than the sum of the parts: forest climate response from joint species distribution models

    Science.gov (United States)

    James S. Clark; Alan E. Gelfand; Christopher W. Woodall; Kai. Zhu

    2014-01-01

    The perceived threat of climate change is often evaluated from species distribution models that are fitted to many species independently and then added together. This approach ignores the fact that species are jointly distributed and limit one another. Species respond to the same underlying climatic variables, and the abundance of any one species can be constrained by...

  19. Metalaxyl toxicity, uptake, and distribution in several ornamental plant species.

    Science.gov (United States)

    Wilson, P C; Whitwell, T; Klaine, S J

    2001-01-01

    Phytoremediation depends on the ability of plants to tolerate and assimilate contaminants. This research characterized the interaction between several ornamental plant species and the fungicidal active ingredient, metalaxyl [N-(2,6-dimethylphenyl)-N-(methoxyacetyl)alanine methyl ester]. Species evaluated included sweetflag (Acorus gramineus Sol. ex Aiton), canna (Canna hybrida L. 'Yellow King Humbert'), parrotfeather [Myriophyllum aquaticum (Vell.) Verdc.], and pickerelweed (Pontederia cordata L.). Metalaxyl tolerance levels for each species were determined by exposing plants for 7 d to solutions containing 0, 5, 10, 25, 50, 75, or 100 mg metalaxyl L-1 aqueous nutrient media. Response endpoints included fresh mass production after 7 d exposure and 7 d post-exposure and quantum efficiency using dark-adapted (Fv/Fm) and light-adapted (fluorescence yields) plants. Metalaxyl uptake and distribution within the plant was determined by growing plants in aqueous nutrient media containing 1.18 x 10(6) Bq L-1 [14C]metalaxyl (0.909 mg L-1) for 1, 3, 5, or 7 d. Plant tissues were combusted and analyzed by liquid scintillation counting. Metalaxyl had no effects on the endpoints measured, except for fresh mass production of sweetflag at the 75 and 100 mg L-1 treatment levels. However, leaf necrosis was apparent in most species after 5 d exposure to concentrations greater than 25 mg L-1. Metalaxyl removal from the spiked nutrient media ranged from 15 to 60% during the 7-d exposure period. The majority of metalaxyl removed from the solution was detected within individual plants. In nearly all cases, activity from the radiolabeled pesticide accumulated in the leaves. Uptake of metalaxyl was correlated with water uptake throughout the 7 d. These results suggest that all species examined may be good candidates for incorporation into a phytoremediation scheme for metalaxyl.

  20. Species distribution and susceptibility profile of Candida species in a Brazilian public tertiary hospital

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    Montelli Augusto

    2010-01-01

    Full Text Available Abstract Background Species identification and antifungal susceptibility tests were carried out on 212 Candida isolates obtained from bloodstream infections, urinary tract infections and dialysis-associated peritonitis, from cases attended at a Brazilian public tertiary hospital from January 1998 to January 2005. Findings Candida albicans represented 33% of the isolates, Candida parapsilosis 31.1%, Candida tropicalis 17.9%,Candida glabrata 11.8%, and others species 6.2%. In blood culture, C. parapsilosis was the most frequently encountered species (48%. The resistance levels to the antifungal azoles were relatively low for the several species, except for C. tropicalis and C. glabrata. Amphotericin B resistance was observed in 1 isolate of C. parapsilosis. Conclusions The species distribution and antifungal susceptibility herein observed presented several epidemiological features common to other tertiary hospitals in Latin American countries. It also exhibited some peculiarity, such as a very high frequency of C. parapsilosis both in bloodstream infections and dialysis-associated peritonitis. C. albicans also occurred in an important number of case infections, in all evaluated clinical sources. C. glabrata presented a high proportion of resistant isolates. The data emphasize the necessity to carry out the correct species identification accompanied by the susceptibility tests in all tertiary hospitals.

  1. Likelihood analysis of species occurrence probability from presence-only data for modelling species distributions

    Science.gov (United States)

    Royle, J. Andrew; Chandler, Richard B.; Yackulic, Charles; Nichols, James D.

    2012-01-01

    1. Understanding the factors affecting species occurrence is a pre-eminent focus of applied ecological research. However, direct information about species occurrence is lacking for many species. Instead, researchers sometimes have to rely on so-called presence-only data (i.e. when no direct information about absences is available), which often results from opportunistic, unstructured sampling. MAXENT is a widely used software program designed to model and map species distribution using presence-only data. 2. We provide a critical review of MAXENT as applied to species distribution modelling and discuss how it can lead to inferential errors. A chief concern is that MAXENT produces a number of poorly defined indices that are not directly related to the actual parameter of interest – the probability of occurrence (ψ). This focus on an index was motivated by the belief that it is not possible to estimate ψ from presence-only data; however, we demonstrate that ψ is identifiable using conventional likelihood methods under the assumptions of random sampling and constant probability of species detection. 3. The model is implemented in a convenient r package which we use to apply the model to simulated data and data from the North American Breeding Bird Survey. We demonstrate that MAXENT produces extreme under-predictions when compared to estimates produced by logistic regression which uses the full (presence/absence) data set. We note that MAXENT predictions are extremely sensitive to specification of the background prevalence, which is not objectively estimated using the MAXENT method. 4. As with MAXENT, formal model-based inference requires a random sample of presence locations. Many presence-only data sets, such as those based on museum records and herbarium collections, may not satisfy this assumption. However, when sampling is random, we believe that inference should be based on formal methods that facilitate inference about interpretable ecological quantities

  2. [Candidemia in Pediatrics: Species distribution and antifungal susceptibility].

    Science.gov (United States)

    Guzzetti, Luciana B; Vescina, Cecilia M; Gil, M Florencia; Gatti, Blanca M

    2017-07-19

    Serious infections caused by Candida yeasts are frequent in the hospital population. Due to differences in species distribution and antifungal susceptibility testing depending on the geographic area and the type of patient, it is important to study the epidemiology of each institution. For this purpose, we conducted a retrospective, descriptive study on the occurrence of candidemia in the Children's Hospital "Superiora Sor María Ludovica" of the city of La Plata. In a 6-year period (2010-2015), 177 candidemia episodes were recorded. The predominant species were Candida albicans (45%) and Candida parapsilosis (28%). The hospital wards with the highest number of candidemia episodes were the pediatric, neonatal and cardiovascular intensive care units (58%). No resistance to amphotericin B was observed throughout the period whereas resistance to azoles was limited to 4 strains of less frequent species. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Coseismic slip distributions of the 26 December 2004 Sumatra-Andaman and 28 March 2005 Nias earthquakes from GPS static offsets

    Science.gov (United States)

    Banerjee, P.; Pollitz, F.; Nagarajan, B.; Burgmann, R.

    2007-01-01

    Static offsets produced by the 26 December 2004 M ???9 Sumatra-Andaman earthquake as measured by Global Positioning System (GPS) reveal a large amount of slip along the entire ???1300 km-long rupture. Most seismic slip inversions place little slip on the Andaman segment. whereas both near-field and far-field GPS offsets demand large slip on the Andaman segment. We compile available datasets of the static offset to render a more detailed picture of the static-slip distribution. We construct geodetic offsets such that postearthquake positions of continuous GPS sites are reckoned to a time 1 day after the earthquake and campaign GPS sites are similarly corrected for postseismic motions. The newly revised slip distribution (Mw 9.22) reveals substantial segmentation of slip along the Andaman Islands, with the southern quarter slipping ???15 m in unison with the adjacent Nicobar and northern Sumatran segments of length ???700 km. We infer a small excess of geodetic moment relative to the seismic moment. A similar compilation of GPS offsets from the 28 March 2005 Nias earthquake is well explained with dip slip averaging several meters (Mw = 8.66) distributed primarily at depths greater than 20 km.

  4. Geographical distribution and ecology of the Armillaria species in western Europe.

    NARCIS (Netherlands)

    Guillaumin, J.J.; Mohammed, C.; Anselmi, N.; Courtecuisse, R.; Gregory, S.C.; Holdenrieder, O.; Intini, M.; Lung, B.; Marxmüller, H.; Morrison, D.; Rishbeth, J.; Termorshuizen, A.J.; Tirro, A.; Dam, van B.

    1993-01-01

    Over 4000 records of the six European Armillaria species were compiled to give distribution maps and host lists for each species. Differences in geographical and altitudinal distribution, pathogenicity, dissemination and ecological role are discussed.

  5. Discrimination of Three Panax Species Based on Differences in Volatile Organic Compounds Using a Static Headspace GC-MS-Based Metabolomics Approach.

    Science.gov (United States)

    Chen, Xiao-Jia; Qiu, Jian-Feng; Wang, Yi-Tao; Wan, Jian-Bo

    2016-01-01

    Panax ginseng (Asian ginseng), Panax quinquefolium (American ginseng) and Panax notoginseng (notoginseng) are highly valuable tonic herbs derived from the Panax genus that have similar morphological appearances and odors but different pharmacological activities and clinical indications. Thus, the authentication of these three Panax species is crucial for ensuring the quality, safety and efficacy of medication. In the present study, a static headspace gas chromatography - mass spectrometry (GC-MS) followed by a multivariate statistical analysis was developed to globally characterize the volatile organic compound (VOC) profiles in P. ginseng, P. quinquefolium, and P. notoginseng, and subsequently to discover differentiating chemical markers. Under the optimized conditions, the headspace VOCs of a total of 49 batches of Panax herbs derived from the three Panax species were profiled, and the dataset of sample code, [Formula: see text]-m/z pair and ion intensity was processed by unsupervised principal component analysis (PCA) and by supervised partial least squared discriminant analysis (PLS-DA) to comprehensively compare the chemical differences in Panax across the species. The results demonstrated that Panax herbs derived from three species possess obviously diverse chemical characteristics of VOCs, PCA, and PLS-DA. According to their VOC profiles, 49 tested samples could be clearly differentiated according to species. Chemomarker 1, 2, and 4 might be used as unique chemical markers of P. ginseng, P. notoginseng and P. quinquefolium, respectively. Our findings indicate that static headspace GC-MS-based VOC profiling, combined with multivariate statistical analysis, provide a reliable tool to discriminate between the three Panax species and to identify their differentiation markers, which will be helpful for ensuring their quality, safety and efficacy.

  6. Study on Finite Element Model Updating in Highway Bridge Static Loading Test Using Spatially-Distributed Optical Fiber Sensors

    Science.gov (United States)

    Wu, Bitao; Lu, Huaxi; Chen, Bo; Gao, Zhicheng

    2017-01-01

    A finite model updating method that combines dynamic-static long-gauge strain responses is proposed for highway bridge static loading tests. For this method, the objective function consisting of static long-gauge stains and the first order modal macro-strain parameter (frequency) is established, wherein the local bending stiffness, density and boundary conditions of the structures are selected as the design variables. The relationship between the macro-strain and local element stiffness was studied first. It is revealed that the macro-strain is inversely proportional to the local stiffness covered by the long-gauge strain sensor. This corresponding relation is important for the modification of the local stiffness based on the macro-strain. The local and global parameters can be simultaneously updated. Then, a series of numerical simulation and experiments were conducted to verify the effectiveness of the proposed method. The results show that the static deformation, macro-strain and macro-strain modal can be predicted well by using the proposed updating model. PMID:28753912

  7. Do predictions from Species Sensitivity Distributions match with field data?

    Science.gov (United States)

    Smetanová, S; Bláha, L; Liess, M; Schäfer, R B; Beketov, M A

    2014-06-01

    Species Sensitivity Distribution (SSD) is a statistical model that can be used to predict effects of contaminants on biological communities, but only few comparisons of this model with field studies have been conducted so far. In the present study we used measured pesticides concentrations from streams in Germany, France, and Finland, and we used SSD to calculate msPAF (multiple substance potentially affected fraction) values based on maximum toxic stress at localities. We compared these SSD-based predictions with the actual effects on stream invertebrates quantified by the SPEARpesticides bioindicator. The results show that the msPAFs correlated well with the bioindicator, however, the generally accepted SSD threshold msPAF of 0.05 (5% of species are predicted to be affected) severely underestimated the observed effects (msPAF values causing significant effects are 2-1000-times lower). These results demonstrate that validation with field data is required to define the appropriate thresholds for SSD predictions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Termite Species Distribution and Flight Periods on Oahu, Hawaii.

    Science.gov (United States)

    Tong, Reina L; Grace, J Kenneth; Mason, Makena; Krushelnycky, Paul D; Spafford, Helen; Aihara-Sasaki, Maria

    2017-06-05

    Termites are economically-important structural pests, costing residents of Hawaii over $100 million annually. On Oahu, the last published termite swarming survey occurred from 1969 to 1971, and the last termite hand-collection survey occurred from 1998 to 2000. To contribute data on termite occurrences on Oahu, a light-trap survey took place from February 2011 to September 2012, and a hand-collection survey occurred from September to November 2012. Formosan subterranean termite, Coptotermes formosanus Shiraki, swarming was compared over the duration of the study, finding peak swarming in May 2011. C. formosanus alate activity density was regressed with environmental factors, finding a negative correlation with average wind speed and a positive correlation with average rainfall. Coptotermes gestroi (Wasmann) alates were observed in April, June, and July 2011 and in June 2012. Four species of termites were found in the hand-collection survey of 44 sites: Incisitermes immigrans (Snyder) ( n = 8/44), C. formosanus ( n = 2/44), Cryptotermes cynocephalus Light ( n = 1/44), and Neotermes sp. ( n = 1/44). This study contributes to distribution data for termite species on Oahu and records alate activity for two important termite pests.

  9. Mollusca of the Magellan Region. A checklist of the species and their distribution

    Directory of Open Access Journals (Sweden)

    Katrin Linse

    1999-12-01

    Full Text Available The Molluscan species collected during the Victor Hensen Joint Magellan Campaign 1994 served as the basis for this species list. The list was then completed by literature data on the distribution of molluscs around the Falkland Islands, the other Scotia Arc Islands, Antarctica and the Kerguelen Islands. 397 Magellan species are known: 10 species of Aplacophora, 250 species of Gastropoda, 6 species of Scaphopoda and 131 species of Bivalvia. Polyplacophora and Cephalopoda are not included because both taxa need revision.

  10. Species delimitation of the Hyphydrus ovatus complex in western Palaearctic with an update of species distributions (Coleoptera, Dytiscidae

    Directory of Open Access Journals (Sweden)

    Johannes Bergsten

    2017-06-01

    Full Text Available The species status of Hyphydrus anatolicus Guignot, 1957 and H. sanctus Sharp, 1882, previously often confused with the widespread H. ovatus (Linnaeus, 1760, are tested with molecular and morphological characters. Cytochrome c oxidase subunit 1 (CO1 was sequenced for 32 specimens of all three species. Gene-trees were inferred with parsimony, time-free bayesian and strict clock bayesian analyses. The GMYC model was used to estimate species limits. All three species were reciprocally monophyletic with CO1 and highly supported. The GMYC species delimitation analysis unequivocally delimited the three species with no other than the three species solution included in the confidence interval. A likelihood ratio test rejected the one-species null model. Important morphological characters distinguishing the species are provided and illustrated. New distributional data are given for the following species: Hyphydrus anatolicus from Slovakia and Ukraine, and H. aubei Ganglbauer, 1891, and H. sanctus from Turkey.

  11. Species delimitation of the Hyphydrus ovatus complex in western Palaearctic with an update of species distributions (Coleoptera, Dytiscidae).

    Science.gov (United States)

    Bergsten, Johannes; Weingartner, Elisabeth; Hájek, Jiří

    2017-01-01

    The species status of Hyphydrus anatolicus Guignot, 1957 and H. sanctus Sharp, 1882, previously often confused with the widespread H. ovatus (Linnaeus, 1760), are tested with molecular and morphological characters. Cytochrome c oxidase subunit 1 (CO1) was sequenced for 32 specimens of all three species. Gene-trees were inferred with parsimony, time-free bayesian and strict clock bayesian analyses. The GMYC model was used to estimate species limits. All three species were reciprocally monophyletic with CO1 and highly supported. The GMYC species delimitation analysis unequivocally delimited the three species with no other than the three species solution included in the confidence interval. A likelihood ratio test rejected the one-species null model. Important morphological characters distinguishing the species are provided and illustrated. New distributional data are given for the following species: Hyphydrus anatolicus from Slovakia and Ukraine, and H. aubei Ganglbauer, 1891, and H. sanctus from Turkey.

  12. Modeling the Current and Future Distribution of Treeline Species in the Nepal Himalaya

    Science.gov (United States)

    Chhetri, P. K.; Cairns, D. M.

    2015-12-01

    Knowledge of the current distribution of treeline species is important for predicting their future distribution in the landscape. Many studies have indicated that treeline will advance with climate change. Treeline advance will result in a loss of alpine biodiversity because the advancing treeline will fragment alpine ecosystems. A species distribution modeling approach using predicted climate data can increase our understanding of how treeline species will expand their range in the future. We used the Maxent model to predict the current and future distributions of three dominant treeline species, Abies spectabilis, Betula utilis, and Pinus wallichiana, of the Nepal Himalaya. The Maxent model predicted that the distribution of treeline species will change significantly under future climate change scenarios. The range of these treeline species will expand northward or upslope in response to future climate change. The model also indicated that temperature-related climatic variables are the most important determinants of the distribution of treeline species.

  13. 3D Model Studies on the Effect of Bed and Powder Type Upon Radial Static Pressure and Powder Distribution in Metallurgical Shaft Furnaces

    Directory of Open Access Journals (Sweden)

    Panic B.

    2017-09-01

    Full Text Available The flow of gases in metallurgical shaft furnaces has a decisive influence on the course and process efficiency. Radial changes in porosity of the bed cause uneven flow of gas along the radius of the reactor, which sometimes is deliberate and intentional. However, holdup of solid particles in descending packed beds of metallurgical shaft furnaces can lead to unintentional changes in porosity of the bed along the radial reactor. Unintentional changes in porosity often disrupt the flow of gas causing poor performance of the furnace. Such disruptions of flow may occur in the blast furnace due to high level of powder content in gas caused by large amount of coal dust/powder insufflated as fuel substitute. The paper describes the model test results of radial distribution of static pressure and powder hold up within metallurgical reactor. The measurements were carried out with the use of 3D physical model of two-phase flow gas-powder in the moving (descending packed bed. Sinter or blast furnace pellets were used as packed bed while carbon powder or iron powder were used as the powder. Wide diversity within both static pressure distribution and powder distribution along the radius of the reactor were observed once the change in the type of powder occurred.

  14. On the Iberian distribution of the species of Tipula, subgenus Tipula (Diptera, Tipulidae)

    OpenAIRE

    Oosterbroek, Pjotr

    1994-01-01

    A list is provided for the species of Tipula, subgenus Tipula, indicating from which Spanish and Portuguese provinces they are known. T. (T.) oleracea is apparently distributed throughout the peninsula, the other three species and kleinschmidti) seem to possess a more limited distribution. The four species are recorded here for the first time from Portugal. (paludosa, mediterranean

  15. Ice age distriutions of European small mammals: insights from species distribution modelling

    DEFF Research Database (Denmark)

    Fløjgaard, Camilla; Normand, Signe; Skov, Flemming

    2009-01-01

    evidence. Our aim was to investigate the potential refuge locations using species distribution modelling to estimate the geographical distribution of suitable climatic conditions for selected rodent species during the LGM. Location Eurasia. Methods Presence/absence data for seven rodent species with range...

  16. Global geographic distribution of Trichinella species and genotypes.

    Science.gov (United States)

    Feidas, Haralambos; Kouam, Marc K; Kantzoura, Vaia; Theodoropoulos, Georgios

    2014-08-01

    Maximum entropy ecological niche modeling was utilized to describe the global geographic distribution of Trichinella species and genotypes and to assess their invasive risk in new areas other than the ones currently known. Also, space-time scan statistic was utilized to identify global spatiotemporal clusters of infection. A database containing 3209 records for 12 species and genotypes identified at the International Trichinella Reference Center (ITRC) as well as climate, elevation, and land cover data extracted from various databases were used. Ecological niche modeling implemented in the Maxent program indicated new potential ranges for T. spiralis (T1), T. nativa (T2), T. britovi (T3), T. pseudospiralis (T4), T. murrelli (T5), T6, T. papuae (T10), and T. zimbabwensis (T11). The area under the curve values for the test data of the models ranged from 0.901 to 0.998, indicating that the models were very good to excellent. The most important bioclimatic factor in modeling the ranges for T. spiralis (T1), T. nativa (T2), T. britovi (T3), T6, and T. zimbabwensis (T11) was temperature, for T. pseudospiralis (T4) and T. papuae (T10) was precipitation, and for T. murrelli (T5) was land cover. T. spiralis (T1), T. britovi (T3), and T. pseudospiralis (T4) had the same primary land cover which was "Grass Crops". The primary land covers were "Conifer Boreal Forest" for T. nativa (T2), "Cool Fields and Woods" for T. murrelli (T5), "Upland Tundra" for T6, "Tropical Rainforest" for T. papuae (T10), and "Crops and Town" for T. zimbabwensis (T11). The scan statistic analyses revealed the presence of significant spatiotemporal clusters (p<0.05) for T. spiralis (T1), T. nativa (T2), T. britovi (T3), T. pseudospiralis (T4), T. murrelli (T5), T6, and T. nelsoni (T7). No significant clusters were found for T. papuae (T10) and T. zimbabwensis (T11). Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Distribution patterns of rare earth elements in various plant species

    Energy Technology Data Exchange (ETDEWEB)

    Wyttenbach, A.; Tobler, L.; Furrer, V. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The elements La, Ce, Nd, Sm, Eu, Gd, Tb, Yb and Lu have been determined in 6 different plant species by neutron activation analysis. When the concentrations of each species were normalized to Norway spruce, smooth curves were obtained which revealed systematic inter-species differences. (author) 3 figs., 4 refs.

  18. Quantifying the effect of habitat availability on species distributions.

    Science.gov (United States)

    Aarts, Geert; Fieberg, John; Brasseur, Sophie; Matthiopoulos, Jason

    2013-11-01

    1. If animals moved randomly in space, the use of different habitats would be proportional to their availability. Hence, deviations from proportionality between use and availability are considered the tell-tale sign of preference. This principle forms the basis for most habitat selection and species distribution models fitted to use-availability or count data (e.g. MaxEnt and Resource Selection Functions). 2. Yet, once an essential habitat type is sufficiently abundant to meet an individual's needs, increased availability of this habitat type may lead to a decrease in the use/availability ratio. Accordingly, habitat selection functions may estimate negative coefficients when habitats are superabundant, incorrectly suggesting an apparent avoidance. Furthermore, not accounting for the effects of availability on habitat use may lead to poor predictions, particularly when applied to habitats that differ considerably from those for which data have been collected. 3. Using simulations, we show that habitat use varies non-linearly with habitat availability, even when individuals follow simple movement rules to acquire food and avoid risk. The results show that the impact of availability strongly depends on the type of habitat (e.g. whether it is essential or substitutable) and how it interacts with the distribution and availability of other habitats. 4. We demonstrate the utility of a variety of existing and new methods that enable the influence of habitat availability to be explicitly estimated. Models that allow for non-linear effects (using b-spline smoothers) and interactions between environmental covariates defining habitats and measures of their availability were best able to capture simulated patterns of habitat use across a range of environments. 5. An appealing aspect of some of the methods we discuss is that the relative influence of availability is not defined a priori, but directly estimated by the model. This feature is likely to improve model prediction

  19. Determining the factors affecting the distribution of Muscari latifolium, an endemic plant of Turkey, and a mapping species distribution model.

    Science.gov (United States)

    Yilmaz, Hatice; Yilmaz, Osman Yalçın; Akyüz, Yaşar Feyza

    2017-02-01

    Species distribution modeling was used to determine factors among the large predictor candidate data set that affect the distribution of Muscari latifolium, an endemic bulbous plant species of Turkey, to quantify the relative importance of each factor and make a potential spatial distribution map of M. latifolium. Models were built using the Boosted Regression Trees method based on 35 presence and 70 absence records obtained through field sampling in the Gönen Dam watershed area of the Kazdağı Mountains in West Anatolia. Large candidate variables of monthly and seasonal climate, fine-scale land surface, and geologic and biotic variables were simplified using a BRT simplifying procedure. Analyses performed on these resources, direct and indirect variables showed that there were 14 main factors that influence the species' distribution. Five of the 14 most important variables influencing the distribution of the species are bedrock type, Quercus cerris density, precipitation during the wettest month, Pinus nigra density, and northness. These variables account for approximately 60% of the relative importance for determining the distribution of the species. Prediction performance was assessed by 10 random subsample data sets and gave a maximum the area under a receiver operating characteristic curve (AUC) value of 0.93 and an average AUC value of 0.8. This study provides a significant contribution to the knowledge of the habitat requirements and ecological characteristics of this species. The distribution of this species is explained by a combination of biotic and abiotic factors. Hence, using biotic interaction and fine-scale land surface variables in species distribution models improved the accuracy and precision of the model. The knowledge of the relationships between distribution patterns and environmental factors and biotic interaction of M. latifolium can help develop a management and conservation strategy for this species.

  20. The distribution of introduced mollusc species in Southern Africa

    NARCIS (Netherlands)

    Bruggen, van A.C.

    1964-01-01

    Artificial distribution patterns of animals and plants may be defined as those caused or fostered deliberately or accidentally by man. Consequently we can distinguish two types of artificial distribution, viz., that of animals accidentally distributed by man (rats, mice, insects, slugs, etc.) and

  1. Do species distribution models predict species richness in urban and natural green spaces? A case study using amphibians

    Science.gov (United States)

    Urban green spaces are potentially important to biodiversity conservation because they represent habitat islands in a mosaic of development, and could harbor high biodiversity or provide connectivity to nearby habitat. Presence only species distribution models (SDMs) represent a ...

  2. Gridded Species Distribution, Version 1: Mammals of the Americas Presence Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mammals of the Americas Presence Grids of the Gridded Species Distribution, Version 1 is a reclassified version of the original grids of the mammal species...

  3. Gridded Species Distribution, Version 1: Birds of the Americas Presence Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — The Birds of the Americas Family Presence Grids of the Gridded Species Distribution, Version 1 is a reclassified version of the original grids of the bird species...

  4. Flat feet, happy feet? Comparison of the dynamic plantar pressure distribution and static medial foot geometry between Malawian and Dutch adults.

    Science.gov (United States)

    Stolwijk, Niki M; Duysens, Jacques; Louwerens, Jan Willem K; van de Ven, Yvonne Hm; Keijsers, Noël Lw

    2013-01-01

    In contrast to western countries, foot complaints are rare in Africa. This is remarkable, as many African adults walk many hours each day, often barefoot or with worn-out shoes. The reason why Africans can withstand such loading without developing foot complaints might be related to the way the foot is loaded. Therefore, static foot geometry and dynamic plantar pressure distribution of 77 adults from Malawi were compared to 77 adults from the Netherlands. None of the subjects had a history of foot complaints. The plantar pressure pattern as well as the Arch Index (AI) and the trajectory of the center of pressure during the stance phase were calculated and compared between both groups. Standardized pictures were taken from the feet to assess the height of the Medial Longitudinal Arch (MLA). We found that Malawian adults: (1) loaded the midfoot for a longer and the forefoot for a shorter period during roll off, (2) had significantly lower plantar pressures under the heel and a part of the forefoot, and (3) had a larger AI and a lower MLA compared to the Dutch. These findings demonstrate that differences in static foot geometry, foot loading, and roll off technique exist between the two groups. The advantage of the foot loading pattern as shown by the Malawian group is that the plantar pressure is distributed more equally over the foot. This might prevent foot complaints.

  5. Remote sensing and GIS applications for modeling species distributions

    Science.gov (United States)

    Harris, Grant

    Habitat loss is the leading cause of species endangerment. It fragments what remains (most harmful for habitat specialists) and isolates populations (applicable to all species). The fragments, parks and other protected areas where species remain are often too small for the long-term persistence of many species. Although these effects are more pronounced in tropical forests, where most species live, the problem is so widespread that it manifests itself across suites of ecosystems and taxa. Mitigating the problems caused by habitat and population fragmentation requires more information. Specifically, we must determine which species are most extinction prone, find ways to cheaply and quickly determine priority areas for conservation, quantify the minimum areas required for species persistence, and identify the key variables needed for species presence. Here, I analyze each of these four key points, using a spectrum of species, and a variety of remote sensing and GIS techniques. For habitat specialists, exemplified by tropical forest birds, I quantify habitat loss directly. It's simply a matter of measuring the remaining forest. To model habitat generalists, such as African elephants, I incorporate habitat and other variables (water, people, greenness) that dictate their presence. For birds, I find that habitat loss affects all forest endemic species equally. Species not threatened have large remaining ranges and high abundances in their ranges. My methods also refine conservation priorities in biological hotspots. The key lies in finding where species live now, and broad-scale natural history information plus coarse-scale imagery suits this purpose. Coarse imagery is also sufficient to understand the minimum range size at which birds become threatened. Be it habitat loss directly or induced by climate change, bird ranges must be over 20,000 km2 in lowland species, and 10,000 km2 for montane birds to avoid threat. For elephants, it is water and people that predict

  6. VBORNET gap analysis: Mosquito vector distribution models utilised to identify areas of potential species distribution in areas lacking records.

    Directory of Open Access Journals (Sweden)

    Francis Schaffner

    2016-12-01

    Full Text Available This is the second of a number of planned data papers presenting modelled vector distributions produced originally during the ECDC funded VBORNET project. This work continues under the VectorNet project now jointly funded by ECDC and EFSA. Further data papers will be published after sampling seasons when more field data will become available allowing further species to be modelled or validation and updates to existing models.  The data package described here includes those mosquito species first modelled in 2013 & 2014 as part of the VBORNET gap analysis work which aimed to identify areas of potential species distribution in areas lacking records. It comprises three species models together with suitability masks based on land class and environmental limits. The species included as part of this phase are the mosquitoes 'Aedes vexans', 'Anopheles plumbeus' and 'Culex modestus'. The known distributions of these species within the area covered by the project (Europe, the ­Mediterranean Basin, North Africa, and Eurasia are currently incomplete to a greater or lesser degree. The models are designed to fill the gaps with predicted distributions, to provide a assistance in ­targeting surveys to collect distribution data for those areas with no field validated information, and b a first indication of the species distributions within the project areas.

  7. Strong neutral spatial effects shape tree species distributions across life stages at multiple scales.

    Directory of Open Access Journals (Sweden)

    Yue-Hua Hu

    Full Text Available Traditionally, ecologists use lattice (regional summary count data to simulate tree species distributions to explore species coexistence. However, no previous study has explicitly compared the difference between using lattice count and basal area data and analyzed species distributions at both individual species and community levels while simultaneously considering the combined scenarios of life stage and scale. In this study, we hypothesized that basal area data are more closely related to environmental variables than are count data because of strong environmental filtering effects. We also address the contribution of niche and the neutral (i.e., solely dependent on distance factors to species distributions. Specifically, we separately modeled count data and basal area data while considering life stage and scale effects at the two levels with simultaneous autoregressive models and variation partitioning. A principal coordinates of neighbor matrix (PCNM was used to model neutral spatial effects at the community level. The explained variations of species distribution data did not differ significantly between the two types of data at either the individual species level or the community level, indicating that the two types of data can be used nearly identically to model species distributions. Neutral spatial effects represented by spatial autoregressive parameters and the PCNM eigenfunctions drove species distributions on multiple scales, different life stages and individual species and community levels in this plot. We concluded that strong neutral spatial effects are the principal mechanisms underlying the species distributions and thus shape biodiversity spatial patterns.

  8. U.S. Geological Survey Gap Analysis Program Species Distribution Models

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — GAP distribution models represent the areas where species are predicted to occur based on habitat associations. GAP distribution models are the spatial arrangement...

  9. Relating biomarkers to whole-organism effects using species sensitivity distributions : A pilot study for marine species exposed to oil

    NARCIS (Netherlands)

    Smit, M.G.D.; Bechmann, R.K.; Hendriks, A.J.; Skadsheim, A.; Larsen, B.K.; Baussant, T.; Bamber, S.; Sannei, S.

    2009-01-01

    Biomarkers are widely used to measure environmental impacts on marine species. For many biomarkers, it is not clear how the signal levels relate to effects on the whole organism. This paper shows how species sensitivity distributions (SSDs) can be applied to evaluate multiple biomarker responses in

  10. Relating biomarkers to whole-organism effects using species sensitivity distributions: a pilot study for marine species exposed to oil

    NARCIS (Netherlands)

    Smit, M.G.D.; Bechmann, R.K.; Hendriks, A.J.; Skadsheim, A.; Larsen, B.K.

    2009-01-01

    Biomarkers are widely used to measure environmental impacts on marine species. For many biomarkers, it is not clear how the signal levels relate to effects on the whole organism. This paper shows how species sensitivity distributions (SSDs) can be applied to evaluate multiple biomarker responses in

  11. Iodine uptake and distribution in horticultural and fruit tree species

    Directory of Open Access Journals (Sweden)

    Alessandra Caffagni

    2012-07-01

    Full Text Available Iodine is an essential microelement for humans and iodine deficiency disorder (IDD is one of the most widespread nutrient-deficiency diseases in the world. Iodine biofortification of plants provides an attractive opportunity to increase iodine intake in humans and to prevent and control IDD. This study was conducted to investigate the iodine uptake and accumulation in edible portion of two fruit trees: plum and nectarine, and two horticultural crops: tomato and potato. Two type of iodine treatments (soil and foliar spray application, and, for fresh market tomato, two production systems (open field and greenhouse hydroponic culture were tested. The distribution of iodine in potato stem and leaves, and in plum tree fruits, leaves, and branches was investigated. Iodine content of potato tubers after postharvest storage and processing (cooking, and iodine content of nectarine fruits after postharvest storage and processing (peeling were also determined. Differences in iodine accumulation were observed among the four crops, between applications, and between production systems. In open field, the maximum iodine content ranged from 9.5 and 14.3 μg 100 g−1 for plum and nectarine fruit, to 89.4 and 144.0 μg 100 g−1 for potato tuber and tomato fruit, respectively. These results showed that nectarine and plum tree accumulated significantly lower amounts of iodine in their edible tissues, in comparison with potato and tomato. The experiments also indicated hydroponic culture as the most efficient system for iodine uptake in tomato, since its fresh fruits accumulated up to 2423 μg 100 g−1 of iodine. Iodine was stored mainly in the leaves, in all species investigated. Only a small portion of iodine was moved to plum tree branches and fruits, and to potato stems and tubers. No differences in iodine content after fruit peeling was observed. A significant increase in iodine content of potato was observed after baking, whereas a significant decrease was

  12. Biotic modifiers, environmental modulation and species distribution models

    NARCIS (Netherlands)

    Linder, H. Peter; Bykova, Olga; Dyke, James; Etienne, Rampal S.; Hickler, Thomas; Kuehn, Ingolf; Marion, Glenn; Ohlemueller, Ralf; Schymanski, Stanislaus J.; Singer, Alexander

    2012-01-01

    The ability of species to modulate environmental conditions and resources has long been of interest. In the past three decades the impacts of these biotic modifiers have been investigated as ecosystem engineers, niche constructors, facilitators and keystone species. This environmental modulation can

  13. Thymus species in Ethiopia: Distribution, medicinal value, economic ...

    African Journals Online (AJOL)

    The genus Thymus is one of the genera in the family Lamiaceae. In Ethiopia, it is represented by two endemic species namely Thymus serrulatus and Thymus schimperi. The aims of this study were to identify the types of species from six geographically distant localities in Ethiopia, assess the ethnobotanical and ...

  14. Species distribution and antifungal susceptibility profile of Candida ...

    African Journals Online (AJOL)

    A total of 51 isolates of Candida species were recovered from 122 urine samples. Candida albicans was the most prevalent species 41.2% (21 isolates), followed by C. parapsilosis (27.5%), C. glabrata (17.6%), C. krusei (7.8%) and C. tropicalis (5.9%). Antifungal susceptibility test indicated that 100% and 96.1% of the ...

  15. Ascidians (Tunicata, Ascidiacea: species distribution along the Scotia Arc

    Directory of Open Access Journals (Sweden)

    Marcos Tatiàn

    2005-12-01

    Full Text Available Ascidians are found in all the oceans. The Polar Front is considered a strong barrier, especially for benthic organisms, separating the Southern Ocean from other oceans. Its influence on ascidian species present at the boundary of the Magellan and Antarctic regions along the Scotia Arc and on the species composition at each station is inferred from the samples taken during the “LAMPOS” cruise. Ascidians were collected by Agassiz (AGT and bottom (GSN trawls at depths between 250 and 587 m on different types of substrate. Of 25 identified species/morphospecies one is new and eight were found in new localities, enlarging the known range of five of these species. Muddy bottoms were found to support higher species richness than hard bottoms, and the South Georgia Islands are found to be the northern limit for Antarctic species and the southern limit for Magellan ones. Affinity between the ascidian fauna of the Magellan region and the Antarctic is slightly stronger than was previously considered; there is also a species gradient along the Scotia Arc, which can be regarded as a bridge between the two regions.

  16. Distribution of benthic marine invertebrates at northern latitudes ― An evaluation applying multi-algorithm species distribution models

    Science.gov (United States)

    Meißner, Karin; Fiorentino, Dario; Schnurr, Sarah; Martinez Arbizu, Pedro; Huettmann, Falk; Holst, Sabine; Brix, Saskia; Svavarsson, Jörundur

    2014-01-01

    Different techniques of species distribution modeling were applied to evaluate the distribution of eight benthic marine species in Icelandic waters. The species examined were Symplectoscyphus tricuspidatus, Stegopoma plicatile (both Hydrozoa), Prionospio cirrifera, Amphicteis gunneri (both Polychaeta), Desmosoma strombergi, Eurycope producta (both Isopoda), Andaniella pectinata and Harpinia crenulata (both Amphipoda). Information on 13 environmental variables (temperature mean, temperature mean SD, temperature minimum, temperature maximum, salinity mean, salinity mean SD, oxygen content, particulate organic carbon, seasonal variation index, bottom roughness, sediment thickness, acidification) and records of occurrences of these eight species was collated in an ArcGIS project. Modeling methods applied were MARS, TreeNet, and MaxENT. According to area under the receiver operating curve (AUC) model assessment values, models with moderate to outstanding discriminatory power were found for all species. There was a good overlap in the overall pattern of prediction for most species independent on the modeling technique. Among the three applied techniques MARS seemed to generalize most whereas TreeNet predictions very precisely reflected information from the training data set. The distribution of the selected benthic invertebrate species in Icelandic waters could be linked to a variety of environmental factors related to oceanography, seabed topography and human impact. Their multivariate interactions acted as a structuring force of species distribution, instead of just their one by one individual influence. The selected predictors varied between the different models for the same species. They substituted each other in different models. The expected distribution of the examined species was mapped for a seascape of known environmental settings. Such maps will serve as excellent references in future impact studies and enable the detection of changes in the distribution of

  17. VBORNET Gap Analysis: Sand Fly Vector Distribution Models Utilised to Identify Areas of Potential Species Distribution in Areas Lacking Records

    Directory of Open Access Journals (Sweden)

    Bulent Alten

    2016-12-01

    Full Text Available This is the first of a number of planned data papers presenting modelled vector distributions, the models in this paper were produced during the ECDC funded VBORNET project. This work continues under the VectorNet project now jointly funded by ECDC and EFSA. This data paper contains the sand fly model outputs produced as part of the VBORNET project. Further data papers will be published after sampling seasons when more field data will become available allowing further species to be modelled or validation and updates to existing models. The data package described here includes those sand fly species first modelled in 2013 and 2014 as part of the VBORNET gap analysis work which aimed to identify areas of potential species distribution in areas lacking records. It comprises four species models together with suitability masks based on land class and environmental limits. The species included within this paper are 'Phlebotomus ariasi', 'Phlebotomus papatasi', 'Phlebotomus perniciosus' and 'Phlebotomus tobbi'. The known distributions of these species within the project area (Europe, the Mediterranean Basin, North Africa, and Eurasia are currently incomplete to a greater or lesser degree. The models are designed to fill the gaps with predicted distributions, to provide a assistance in targeting surveys to collect ­distribution data for those areas with no field validated information, and b a first indication of project wide distributions.

  18. Total Mercury Distribution in Different Fish Species Representing ...

    African Journals Online (AJOL)

    All fish species analysed in this study had total mercury concentrations (range: 0.001-0.278 μg g-1) less than the FAO/WHO limit of 0.5 μg g-1 wet weight. The low concentrations of mercury in the fish species obtained in this study do not appear to contribute any significant mercury exposure to the general popula-tion; and ...

  19. Evolution of carbon distribution and mechanical properties during the static strain ageing of heavily drawn pearlitic steel wires

    Energy Technology Data Exchange (ETDEWEB)

    Lamontagne, A. [Univ Lyon, INSA Lyon, MATEIS – UMR CNRS 5510, Bât. St Exupéry, 25 Avenue Jean Capelle, F-69621 Villeurbanne Cedex (France); Massardier, V., E-mail: veronique.massardier@insa-lyon.fr [Univ Lyon, INSA Lyon, MATEIS – UMR CNRS 5510, Bât. St Exupéry, 25 Avenue Jean Capelle, F-69621 Villeurbanne Cedex (France); Sauvage, X. [University of Rouen, GPM, UMR CNRS 6634, BP 12, Avenue de l’Université, 76801 Saint-Etienne du Rouvray (France); Kléber, X. [Univ Lyon, INSA Lyon, MATEIS – UMR CNRS 5510, Bât. St Exupéry, 25 Avenue Jean Capelle, F-69621 Villeurbanne Cedex (France); Mari, D. [Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, Station 3, Lausanne CH-1015 (Switzerland)

    2016-06-14

    The static strain ageing of heavily cold-drawn pearlitic steel wires was investigated using both global techniques and local techniques (Atom Probe Tomography (APT)), in order to highlight how the cold-drawn destabilized microstructure returns to a more stable state during post-drawing treatments between 20 °C and 150 °C. The global techniques (thermoelectric power, differential scanning calorimetry) clearly showed that ageing occurs in three successive ageing stages and is due to a redistribution of the carbon atoms coming from the strain-induced cementite dissolution. The first ageing stage was unambiguously attributed to the carbon segregation to the defects, while the second and third stages were interpreted as being due to the precipitation of intermediate carbides (2nd stage) and cementite (3rd stage). The true strain was not found to significantly affect the ageing kinetics and mechanisms but appeared to play a role in the amount of carbon atoms involved in the different ageing stages. APT analyses confirmed that ageing is governed by the carbon depletion of strain-induced supersaturated ferrite. The strengthening mechanisms associated with the different ageing stages were also discussed.

  20. Tracing glacial refugia fo triturus newts based on mitochondrial DNA phylogeography and species distribution modeling

    NARCIS (Netherlands)

    Wielstra, B.M.; Crnobrnja-Isailovic, Jelka; Litvinchuk, Spartak N.; Reijnen, Bastian T.; Skidmore, A.K.; Sotiropoulos, Konstantinos; Toxopeus, A.G.; Tzankov, Nikolay; Vukov, Tanja; Arntzen, Jan W.

    2013-01-01

    Introduction The major climatic oscillations during the Quaternary Ice Age heavily influenced the distribution of species and left their mark on intraspecific genetic diversity. Past range shifts can be reconstructed with the aid of species distribution modeling and phylogeographical analyses. We

  1. Bayesian image restoration models for combining expert knowledge on recording activity with species distribution data

    NARCIS (Netherlands)

    Bierman, S.M.; Butler, A.; Marion, G.; Kuhn, I.

    2010-01-01

    Biological atlases are, for many species, the only source of information on their distribution over large geographical areas, and are widely used to inform models of the environmental distribution of species. Such data are not collected using standardized survey techniques, however, and spatial

  2. Factors influencing non-native tree species distribution in urban landscapes

    Science.gov (United States)

    Wayne C. Zipperer

    2010-01-01

    Non-native species are presumed to be pervasive across the urban landscape. Yet, we actually know very little about their actual distribution. For this study, vegetation plot data from Syracuse, NY and Baltimore, MD were used to examine non-native tree species distribution in urban landscapes. Data were collected from remnant and emergent forest patches on upland sites...

  3. Current state of the art for statistical modeling of species distributions [Chapter 16

    Science.gov (United States)

    Troy M. Hegel; Samuel A. Cushman; Jeffrey Evans; Falk Huettmann

    2010-01-01

    Over the past decade the number of statistical modelling tools available to ecologists to model species' distributions has increased at a rapid pace (e.g. Elith et al. 2006; Austin 2007), as have the number of species distribution models (SDM) published in the literature (e.g. Scott et al. 2002). Ten years ago, basic logistic regression (Hosmer and Lemeshow 2000)...

  4. On the Iberian distribution of the species of Tipula, subgenus Tipula (Diptera, Tipulidae)

    NARCIS (Netherlands)

    Oosterbroek, Pjotr

    1994-01-01

    A list is provided for the species of Tipula, subgenus Tipula, indicating from which Spanish and Portuguese provinces they are known. T. (T.) oleracea is apparently distributed throughout the peninsula, the other three species and kleinschmidti) seem to possess a more limited distribution. The four

  5. Robustness and accuracy of Maxent niche modelling for Lactuca species distributions in light of collecting expeditions

    NARCIS (Netherlands)

    Cobben, M.M.P.; van Treuren, R.; Castañeda-Álvarez, N.P.; Khoury, C.K.; Kik, C.; van Hintum, T.J.L.

    2015-01-01

    Niche modelling software can be used to assess the probability of detecting a population of a plant species at a certain location. In this study, we used the distribution of the wild relatives of lettuce (Lactuca spp.) to investigate the applicability of Maxent species distribution models for

  6. An analysis of plant species distributions on the floodplain of the ...

    African Journals Online (AJOL)

    Direct gradient analysis was used to determine the distribution of the most common floodplain plant species in relation to elevation above the water surface and distance from the channel, and therefore to the depth and duration of flooding. Species could be ranked and scored according to their distribution in relation to both ...

  7. Mapping National Plant Biodiversity Patterns in South Korea with the MARS Species Distribution Model.

    Directory of Open Access Journals (Sweden)

    Hyeyeong Choe

    Full Text Available Accurate information on the distribution of existing species is crucial to assess regional biodiversity. However, data inventories are insufficient in many areas. We examine the ability of Multivariate Adaptive Regression Splines (MARS multi-response species distribution model to overcome species' data limitations and portray plant species distribution patterns for 199 South Korean plant species. The study models species with two or more observations, examines their contribution to national patterns of species richness, provides a sensitivity analysis of different range threshold cutoff approaches for modeling species' ranges, and presents considerations for species modeling at fine spatial resolution. We ran MARS models for each species and tested four threshold methods to transform occurrence probabilities into presence or absence range maps. Modeled occurrence probabilities were extracted at each species' presence points, and the mean, median, and one standard deviation (SD calculated to define data-driven thresholds. A maximum sum of sensitivity and specificity threshold was also calculated, and the range maps from the four cutoffs were tested using independent plant survey data. The single SD values were the best threshold tested for minimizing omission errors and limiting species ranges to areas where the associated occurrence data were correctly classed. Eight individual species range maps for rare plant species were identified that are potentially affected by resampling predictor variables to fine spatial scales. We portray spatial patterns of high species richness by assessing the combined range maps from three classes of species: all species, endangered and endemic species, and range-size rarity of all species, which could be used in conservation planning for South Korea. The MARS model is promising for addressing the common problem of few species occurrence records. However, projected species ranges are highly dependent on the

  8. Predicting species distributions from checklist data using site-occupancy models

    Science.gov (United States)

    Kery, M.; Gardner, B.; Monnerat, C.

    2010-01-01

    Aim: (1) To increase awareness of the challenges induced by imperfect detection, which is a fundamental issue in species distribution modelling; (2) to emphasize the value of replicate observations for species distribution modelling; and (3) to show how 'cheap' checklist data in faunal/floral databases may be used for the rigorous modelling of distributions by site-occupancy models. Location: Switzerland. Methods: We used checklist data collected by volunteers during 1999 and 2000 to analyse the distribution of the blue hawker, Aeshna cyanea (Odonata, Aeshnidae), a common dragonfly in Switzerland. We used data from repeated visits to 1-ha pixels to derive 'detection histories' and apply site-occupancy models to estimate the 'true' species distribution, i.e. corrected for imperfect detection. We modelled blue hawker distribution as a function of elevation and year and its detection probability of elevation, year and season. Results: The best model contained cubic polynomial elevation effects for distribution and quadratic effects of elevation and season for detectability. We compared the site-occupancy model with a conventional distribution model based on a generalized linear model, which assumes perfect detectability (p = 1). The conventional distribution map looked very different from the distribution map obtained using site-occupancy models that accounted for the imperfect detection. The conventional model underestimated the species distribution by 60%, and the slope parameters of the occurrence-elevation relationship were also underestimated when assuming p = 1. Elevation was not only an important predictor of blue hawker occurrence, but also of the detection probability, with a bell-shaped relationship. Furthermore, detectability increased over the season. The average detection probability was estimated at only 0.19 per survey. Main conclusions: Conventional species distribution models do not model species distributions per se but rather the apparent

  9. Wild Manihot species: botanical aspects, geographic distribution and economic value.

    Science.gov (United States)

    Nassar, Nagib M A; Hashimoto, D Y C; Fernandes, S D C

    2008-01-15

    A total of 98 Manihot species have been recognized in the genus. All of them are native to the tropics of the New World, particularly Brazil and Mexico. The cultigen, Manihot esculenta Crantz (cassava), grows throughout the lowland tropics. Wild species vary in growth habit from acaulescent or short shrubs to tree-like. Because of their adaptations to different conditions, they are gene reservoirs for tackling many abiotic and biotic stresses such as improving root quality and resistance to diseases. They have been used successfully by the first author for improving protein content, seed-fertility, apomixis, resistance to mealy bug, and tolerance to drought. A table of the most important species from an economic viewpoint is presented.

  10. Biotic and abiotic variables show little redundancy in explaining tree species distributions

    DEFF Research Database (Denmark)

    Meier, Elaine S.; Kienast, Felix; Pearman, Peter B.

    2010-01-01

    Abiotic factors such as climate and soil determine the species fundamental niche, which is further constrained by biotic interactions such as interspecific competition. To parameterize this realized niche, species distribution models (SDMs) most often relate species occurrence data to abiotic var...

  11. Modelling the potential spatial distribution of mosquito species using three different techniques

    NARCIS (Netherlands)

    Cianci, Daniela; Hartemink, Nienke; Ibáñez-Justicia, Adolfo

    2015-01-01

    BACKGROUND: Models for the spatial distribution of vector species are important tools in the assessment of the risk of establishment and subsequent spread of vector-borne diseases. The aims of this study are to define the environmental conditions suitable for several mosquito species through species

  12. The distribution, composition and abundance of fish species in two ...

    African Journals Online (AJOL)

    Fish composition and abundance of two Gold mine reservoir were investigated between May, 2008 and May, 2009. Seven fish families comprising of twelve species of fish were caught during the period of study. The families of fish caught included Anabantidae, Channidae, Clariidae, Cichlidae, Melanopluridae, Mormyridae ...

  13. total mercury distribution in different fish species representing

    African Journals Online (AJOL)

    DEPT OF AGRICULTURAL ENGINEERING

    ABSTRACT. Concentrations of total mercury (Hg) were measured in the edible muscle tissues of different fish species representing different trophic levels from the Atlantic Coast of Ghana using Cold. Vapour Atomic Absorption Spectrophotometry (CVAAS). Mercury concentrations were gener- ally found to increase with ...

  14. Spatial distribution and habitat characterisation of mosquito species ...

    African Journals Online (AJOL)

    There was heterogeneity in the relative abundance of Anopheles and Culex species in the aquatic habitats in different locations on land, p<0.001, Bartlett's test. There were more Anopheles mosquito in quary and shoreline swamp puddles, flood plain, and stream edge puddles than natural swamps, rivers and permanent ...

  15. Distribution, animal preference and nutritive value of browse species ...

    African Journals Online (AJOL)

    Browse species serve as the main feed sources for pastoralists' livestock especially during the dry season when herbaceous feed sources are exhausted. The study was conducted in Aba'ala District, Afar Regional State of Ethiopia to assess the indigenous knowledge on browse ecology and use and to investigate the ...

  16. Distribution, diversity and abundance of anuran species in three ...

    African Journals Online (AJOL)

    Most amphibian species were observed and collected between the 18h-21h sampling time frame which confers them as mostly nocturnal in habit. Conservation efforts must be enforced to protect the vegetative structure against unsustainable forest practices in order to protect and maintain the biodiversity status of the region ...

  17. Eco-taxonomic distribution of plant species around motor mechanic ...

    African Journals Online (AJOL)

    Administrator

    2006-10-02

    Oct 2, 2006 ... motor mechanic workshops in Asaba and Benin City,. Nigeria: Identification of oil tolerant plant species. Anoliefo, G. O.1*, Ikhajiagbe, B. 2, Okonofhua, B. O.3 and Diafe, F. V. 1. 1Department of Botany, University of Benin, Benin City, Nigeria. 2Raw Materials Research and Development Council, Abuja, ...

  18. Species composition and distribution of zooplankton in the lower ...

    African Journals Online (AJOL)

    Taxa richness was highest in the lower reach station 6 with a value of 6.79. A general trend of increase in species diversity and richness from upstream to downstream was observed. Inter-and intra-specific relationship revealed highly significant positive correlation (p < 0.01) between Cnidarians and Copepods (r = 0.896), ...

  19. Seasonal distribution and ecology of some Dactylogyrus species ...

    African Journals Online (AJOL)

    In this research, gill parasites of two Cyprinid fish (Alburnus alburnus and Carassius carassius) from the upper basin of Porsuk river were studied. Fish samples were obtained monthly at intervals during 2003 to 2004. The intensity of infection was investigated depending on the parasite species, the years and seasons, and ...

  20. Alien fish species in upper Sakarya River and their distribution ...

    African Journals Online (AJOL)

    However, the fact that the flood plains have been reclaimed, excessive hunting, destruction of the ecologic balance and invasion of the area by the alien fish species threatens the fish stocks in Sakarya River. In this study, we aimed to determine the dispersion area of Carassius gibelio (Bloch, 1782), Oreochromis niloticus ...

  1. Quantifying the effect of habitat availability on species distributions

    NARCIS (Netherlands)

    Aarts, G.M.; Fieberg, J.; Brasseur, S.M.J.M.; Matthiopoulos, J.

    2013-01-01

    1.If animals moved randomly in space, the use of different habitats would be proportional to their availability. Hence, deviations from proportionality between use and availability are considered the tell-tale sign of preference. This principle forms the basis for most habitat selection and species

  2. Composition and distribution of economic tree species in Nagi ...

    African Journals Online (AJOL)

    The inventory of economic trees in Nagi Natural Forest Reserve, Benue state was carried out to determine the status and dominance tree species. A total area of 0.4ha was sampled representing twenty percent of the reserve. Ten (10) sample plots of equal size (20 m x 20m) were randomly selected using simple random ...

  3. Distribution and diversity of mangrove species in Gokana Local ...

    African Journals Online (AJOL)

    Plots 1 and 2 were dominated by Rhizophora racemosa (62.07% and 41.17% respectively). Plots 3 were dominated by R. mangle (4 1.67%) while Plots 4 had 26.56% of Acrostichum aureum and 26.56% of Phoenix reclinata. The overlapping mangrove species occurrence (Laguncularia racemosa and R. mangle) at the ...

  4. Characterization of Quercus species distributed in Jordan using ...

    African Journals Online (AJOL)

    User

    2013-03-20

    Mar 20, 2013 ... Genetic diversity among 25 natural populations of three different species of Quercus in Jordan at morphological and molecular levels using random amplified polymorphic DNA (RAPD) primers was assessed. Significant morphological and molecular variations among and within 25 Quercus populations ...

  5. Species distribution and antifungal sensitivity patterns of vaginal ...

    African Journals Online (AJOL)

    Objectives: To identify yeast isolates in vaginal specimens to species level and determine their antifungal susceptibility patterns. Design: Cross-sectional laboratory-based study. Setting: The Aga Khan University Hospital (AKUH), Nairobi. Subjects: Yeast isolates from high vaginal swabs presented to the laboratory for ...

  6. Distribution Characteristics of Mineral Elements in Tree Species ...

    African Journals Online (AJOL)

    Fiifi Baidoo

    The other families comprised Papilionaceae, Apocynaceae, Sterculiaceae, Connaraceae,. Sapindaceae, Laurraceae, Combretaceae, Bombaceae, Bignoniaceae, Ulmaceae, Annonaceae and. Anacardiaceae, and constituted 34.4% (Fig. 1b). A total of 18 different tree species families were identified in AS and 16 in DS ...

  7. Croatian mayflies (Insecta, Ephemeroptera): species diversity and distribution patterns.

    Science.gov (United States)

    Vilenica, Marina; Gattolliat, Jean-Luc; Mihaljević, Zlatko; Sartori, Michel

    2015-01-01

    Knowledge of the mayfly biodiversity in the Balkan Peninsula is still far from complete. Compared to the neighbouring countries, the mayfly fauna in Croatia is very poorly known. Situated at the crossroads of central and Mediterranean Europe and the Balkan Peninsula, Croatia is divided into two ecoregions: Dinaric western Balkan and Pannonian lowland. Mayflies were sampled between 2003 and 2013 at 171 sites, and a total of 66 species was recorded. Combined with the literature data, the Croatian mayfly fauna reached a total of 79 taxa. Of these, 29 species were recorded for the first time in Croatia while 15 species were not previously recorded in Dinaric western Balkan ecoregion. Based on the mayfly assemblage, sampling sites were first structured by ecoregion and then by habitat type. In comparison with the surrounding countries, the Croatian mayfly fauna is the most similar to the Hungarian and Bosnian fauna. Some morphologically interesting taxa such as Baetis cf. nubecularis Eaton, 1898 and Rhithrogena from the diaphana group were recorded. Ephemera cf. parnassiana Demoulin, 1958, the species previously recorded only from Greece, was also recorded.

  8. How Gaussian competition leads to lumpy or uniform species distributions

    DEFF Research Database (Denmark)

    Pigolotti, Simone; Lopez, Cristóbal; Hernandez-Garcia, Emilio

    2010-01-01

    of the competing species. Most models considered in the literature assume a Gaussian competition kernel. This is unfortunate, since predictions based on such a Gaussian assumption are not robust. In fact, Gaussian kernels are a border case scenario, and slight deviations from this function can lead to either...

  9. Effect of species rarity on the accuracy of species distribution models for reptiles and amphibians in southern California

    Science.gov (United States)

    Franklin, J.; Wejnert, K.E.; Hathaway, S.A.; Rochester, C.J.; Fisher, R.N.

    2009-01-01

    Aim: Several studies have found that more accurate predictive models of species' occurrences can be developed for rarer species; however, one recent study found the relationship between range size and model performance to be an artefact of sample prevalence, that is, the proportion of presence versus absence observations in the data used to train the model. We examined the effect of model type, species rarity class, species' survey frequency, detectability and manipulated sample prevalence on the accuracy of distribution models developed for 30 reptile and amphibian species. Location: Coastal southern California, USA. Methods: Classification trees, generalized additive models and generalized linear models were developed using species presence and absence data from 420 locations. Model performance was measured using sensitivity, specificity and the area under the curve (AUC) of the receiver-operating characteristic (ROC) plot based on twofold cross-validation, or on bootstrapping. Predictors included climate, terrain, soil and vegetation variables. Species were assigned to rarity classes by experts. The data were sampled to generate subsets with varying ratios of presences and absences to test for the effect of sample prevalence. Join count statistics were used to characterize spatial dependence in the prediction errors. Results: Species in classes with higher rarity were more accurately predicted than common species, and this effect was independent of sample prevalence. Although positive spatial autocorrelation remained in the prediction errors, it was weaker than was observed in the species occurrence data. The differences in accuracy among model types were slight. Main conclusions: Using a variety of modelling methods, more accurate species distribution models were developed for rarer than for more common species. This was presumably because it is difficult to discriminate suitable from unsuitable habitat for habitat generalists, and not as an artefact of the

  10. High-resolution pattern of mangrove species distribution is controlled by surface elevation

    Science.gov (United States)

    Leong, Rick C.; Friess, Daniel A.; Crase, Beth; Lee, Wei Kit; Webb, Edward L.

    2018-03-01

    Mangrove vegetation species respond to multiple environmental gradients, and an enhanced understanding of how mangrove species are distributed across these gradients will facilitate conservation and management. Many environmental gradients correlate with tidal inundation; however small-scale inundation patterns resulting from microtopographical changes are difficult to capture empirically. In contrast, surface elevation is often a suitable, measurable and cost-effective proxy for inundation. This study investigated the relationships between species distribution and surface elevation in a mangrove forest in northwest Singapore. Through high-resolution land surveying, we developed a digital elevation model (DEM) and conducted a comprehensive survey of 4380 trees with a stem diameter ≥ 5 cm. A total of 15 species were encountered, and elevation envelopes were generated for 12. Species envelopes were distributed along an elevation continuum, with most species overlapping within the continuum. Spatial autocorrelation (SAC) was present for nine of the 15 species, and when taken into account, species ordering was modified across the elevation continuum. The presence of SAC strongly reinforces the need for research to control for SAC: classical spatial description of mangrove species distribution should be revised to account for ecological factors. This study suggests that (1) surface elevation applies strong controls on species distribution and (2) most mangroves at our study site have similar physiological tolerances.

  11. How much does climate change threaten European forest tree species distributions?

    Science.gov (United States)

    Dyderski, Marcin K; Paź, Sonia; Frelich, Lee E; Jagodziński, Andrzej M

    2018-03-01

    Although numerous species distribution models have been developed, most were based on insufficient distribution data or used older climate change scenarios. We aimed to quantify changes in projected ranges and threat level by the years 2061-2080, for 12 European forest tree species under three climate change scenarios. We combined tree distribution data from the Global Biodiversity Information Facility, EUFORGEN, and forest inventories, and we developed species distribution models using MaxEnt and 19 bioclimatic variables. Models were developed for three climate change scenarios-optimistic (RCP2.6), moderate (RCP4.5), and pessimistic (RPC8.5)-using three General Circulation Models, for the period 2061-2080. Our study revealed different responses of tree species to projected climate change. The species may be divided into three groups: "winners"-mostly late-successional species: Abies alba, Fagus sylvatica, Fraxinus excelsior, Quercus robur, and Quercus petraea; "losers"-mostly pioneer species: Betula pendula, Larix decidua, Picea abies, and Pinus sylvestris; and alien species-Pseudotsuga menziesii, Quercus rubra, and Robinia pseudoacacia, which may be also considered as "winners." Assuming limited migration, most of the species studied would face a significant decrease in suitable habitat area. The threat level was highest for species that currently have the northernmost distribution centers. Ecological consequences of the projected range contractions would be serious for both forest management and nature conservation. © 2017 John Wiley & Sons Ltd.

  12. Identity and distribution of southern African sciaenid fish species of ...

    African Journals Online (AJOL)

    U. canariensis is distributed along the South Africa eastern seaboard from Cape Point to Sodwana Bay and U. robinsoni is known from False Bay to Madagascar and Oman. African Umbrina taxonomy has, however, been hindered by geographic samples that were either too few or consisted of specimens of disparate length ...

  13. Butt-log grade distributions for five Appalachian hardwood species

    Science.gov (United States)

    John R. Myers; Gary W. Miller; Harry V., Jr. Wiant; Joseph E. Barnard; Joseph E. Barnard

    1986-01-01

    Tree quality is an important factor in determining the market value of hardwood timber stands, but many forest inventories do not include estimates of tree quality. Butt-log grade distributions were developed for northern red oak, black oak, white oak, chestnut oak, and yellow-poplar using USDA Forest Service log grades on more than 4,700 trees in West Virginia. Butt-...

  14. thesis abstract: Applying species distribution modeling for the conservation of Iberian protected invertebrates

    OpenAIRE

    Chefaoui, Rosa María

    2011-01-01

    This article outlines the approaches to modeling the distribution of threatened invertebrates using data from atlases, museums and databases. Species Distribution Models (SDMs) are useful for estimating species’ ranges, identifying suitable habitats, and identifying the primary factors affecting species’ distributions. The study tackles the strategies used to obtain SDMs without reliable absence data while exploring their applications for conservation. I examine the conservation s...

  15. Mid-winter European dabbling duck distributions are not linked to species body mass

    DEFF Research Database (Denmark)

    Dalby, Lars; Delany, Simon; Fox, Anthony David

    In order to understand the current changes and to predict future changes in wintering dabbling duck (Anas sp.) distributions in response to climate change, it is important to understand how species distribute themselves on a continental scale in response to temperature. Thermoregulatory costs are...... are more important in shaping mid-winter duck distributions than factors related to thermoregulation alone....

  16. Separating the effects of environment and space on tree species distribution: from population to community.

    Directory of Open Access Journals (Sweden)

    Guojun Lin

    Full Text Available Quantifying the relative contributions of environmental conditions and spatial factors to species distribution can help improve our understanding of the processes that drive diversity patterns. In this study, based on tree inventory, topography and soil data from a 20-ha stem-mapped permanent forest plot in Guangdong Province, China, we evaluated the influence of different ecological processes at different spatial scales using canonical redundancy analysis (RDA at the community level and multiple linear regression at the species level. At the community level, the proportion of explained variation in species distribution increased with grid-cell sizes, primarily due to a monotonic increase in the explanatory power of environmental variables. At the species level, neither environmental nor spatial factors were important determinants of overstory species' distributions at small cell sizes. However, purely spatial variables explained most of the variation in the distributions of understory species at fine and intermediate cell sizes. Midstory species showed patterns that were intermediate between those of overstory and understory species. At the 20-m cell size, the influence of spatial factors was stronger for more dispersal-limited species, suggesting that much of the spatial structuring in this community can be explained by dispersal limitation. Comparing environmental factors, soil variables had higher explanatory power than did topography for species distribution. However, both topographic and edaphic variables were highly spatial structured. Our results suggested that dispersal limitation has an important influence on fine-intermediate scale (from several to tens of meters species distribution, while environmental variability facilitates species distribution at intermediate (from ten to tens of meters and broad (from tens to hundreds of meters scales.

  17. Distribution patterns of invasive alien species in Alabama, USA

    Directory of Open Access Journals (Sweden)

    Xiongwen Chen

    2012-12-01

    Full Text Available Invasive alien species (IAS cause environmental and economical problems. How to effectively manage all IAS at a large area is a challenge.Hypotheses about IAS (such as the “human activity” hypothesis, the “biotic acceptance” and the “biotic resistance” have been proposedfrom numerous studies. Here the state of Alabama in USA, widely occupied by IAS, is used as a case study for characterizing the emergentpatterns of IAS. The results indicate that most IAS are located in metropolitan areas and in the Black Belt area which is a historical intensiveland use area. There are positive relationships between the richness of IAS and the change of human population, the species richness and thenumber of endangered species, as well as the total road length and farmland area across Alabama. This study partially supports the abovethree hypotheses and provides a general pattern of local IAS. Based on possible processes related with IAS, some implications forstrategically managing local IAS are discussed.

  18. The definition of species richness used by species sensitivity distributions approximates observed effects of salinity on stream macroinvertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: ben.kefford@uts.edu.a [School of Applied Sciences, RMIT University, Victoria (Australia); Centre for Environmental Sustainability, Department of Environmental Science, University of Technology Sydney, New South Wales (Australia); Marchant, Richard [Department of Entomology, Museum of Victoria, Victoria (Australia); Schaefer, Ralf B. [School of Applied Sciences, RMIT University, Victoria (Australia); Metzeling, Leon [EPA Victoria, Macleod, Victoria (Australia); Dunlop, Jason E. [Department of Environment and Resource Management, Indooroopilly, Queensland (Australia); National Research Centre for Environmental Toxicology, University of Queensland, Coopers Plains, Queensland (Australia); Choy, Satish C. [Department of Environment and Resource Management, Indooroopilly, Queensland (Australia); Goonan, Peter [South Australia Environment Protection Authority, Adelaide, South Australia (Australia)

    2011-01-15

    The risk of chemicals for ecological communities is often forecast with species sensitivity distributions (SSDs) which are used to predict the concentration which will protect p% of species (PC{sub p} value). However, at the PC{sub p} value, species richness in nature would not necessary be p% less than at uncontaminated sites. The definition of species richness inherent to SSDs (contaminant category richness) contrasts with species richness typically measured in most field studies (point richness). We determine, for salinity in eastern Australia, whether these definitions of stream macroinvertebrate species richness are commensurable. There were strong relationships (r{sup 2} {>=} 0.87) between mean point species, family and Ephemeroptera, Trichoptera and Plecoptera species richness and their respective contamination category richness. Despite differences in the definition of richness used by SSDs and field biomonitoring, their results in terms of relative species loss from salinity in south-east Australia are similar. We conclude that in our system both definitions are commensurable. - Definitions of species richness inherit in SSDs and biomonitoring are for salinity in south-east Australia commensurable.

  19. Fast Determination of Distribution-Connected PV Impacts Using a Variable Time-Step Quasi-Static Time-Series Approach: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Mather, Barry

    2017-08-24

    The increasing deployment of distribution-connected photovoltaic (DPV) systems requires utilities to complete complex interconnection studies. Relatively simple interconnection study methods worked well for low penetrations of photovoltaic systems, but more complicated quasi-static time-series (QSTS) analysis is required to make better interconnection decisions as DPV penetration levels increase. Tools and methods must be developed to support this. This paper presents a variable-time-step solver for QSTS analysis that significantly shortens the computational time and effort to complete a detailed analysis of the operation of a distribution circuit with many DPV systems. Specifically, it demonstrates that the proposed variable-time-step solver can reduce the required computational time by as much as 84% without introducing any important errors to metrics, such as the highest and lowest voltage occurring on the feeder, number of voltage regulator tap operations, and total amount of losses realized in the distribution circuit during a 1-yr period. Further improvement in computational speed is possible with the introduction of only modest errors in these metrics, such as a 91 percent reduction with less than 5 percent error when predicting voltage regulator operations.

  20. Distribution of motor unit potential velocities in the biceps brachii muscle of sprinters and endurance athletes during short static contractions at low force levels.

    Science.gov (United States)

    Klaver-Król, Ewa G; Henriquez, Nizare R; Oosterloo, Sebe J; Klaver, Peter; Kuipers, Harm; Zwarts, Machiel J

    2010-12-01

    In surface electromyography (sEMG), the distribution of motor unit potential (MUP) velocities has been shown to reflect the proportion of faster and slower propagating MUPs. This study investigated whether the distribution of MUP velocities could distinguish between sprinters and endurance athletes in not-specifically trained muscle (biceps brachii). sEMG results were acquired from 15 sprinters and 18 endurance athletes during short static contractions (3.8s) at three force levels: unloaded, 10% and 20% of maximum voluntary contraction. The features extracted from the sEMG were: the mean muscle conduction velocity (CV) - estimated using the inter-peak latency and the cross-correlation methods, the within-subject skewness of MUP velocities (expressing the relative proportions of faster and slower propagating MUPs), and the within-subject standard deviation of MUP velocities. Sprinters had a higher CV than endurance athletes using both methods. Sprinters also demonstrated a greater proportion of fast propagating MUPs, as indicated by the skewness. Thus, the distribution of MUP velocities was able to demonstrate physiological differences between sprinters and endurance athletes during short contractions at low forces. The findings can be extrapolated to the motor unit level. Since the investigated muscle was not involved in specific training, the differences seem to reflect inherited properties. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Tree species distribution in temperate forests is more influenced by soil than by climate.

    Science.gov (United States)

    Walthert, Lorenz; Meier, Eliane Seraina

    2017-11-01

    Knowledge of the ecological requirements determining tree species distributions is a precondition for sustainable forest management. At present, the abiotic requirements and the relative importance of the different abiotic factors are still unclear for many temperate tree species. We therefore investigated the relative importance of climatic and edaphic factors for the abundance of 12 temperate tree species along environmental gradients. Our investigations are based on data from 1,075 forest stands across Switzerland including the cold-induced tree line of all studied species and the drought-induced range boundaries of several species. Four climatic and four edaphic predictors represented the important growth factors temperature, water supply, nutrient availability, and soil aeration. The climatic predictors were derived from the meteorological network of MeteoSwiss, and the edaphic predictors were available from soil profiles. Species cover abundances were recorded in field surveys. The explanatory power of the predictors was assessed by variation partitioning analyses with generalized linear models. For six of the 12 species, edaphic predictors were more important than climatic predictors in shaping species distribution. Over all species, abundances depended mainly on nutrient availability, followed by temperature, water supply, and soil aeration. The often co-occurring species responded similar to these growth factors. Drought turned out to be a determinant of the lower range boundary for some species. We conclude that over all 12 studied tree species, soil properties were more important than climate variables in shaping tree species distribution. The inclusion of appropriate soil variables in species distribution models allowed to better explain species' ecological niches. Moreover, our study revealed that the ecological requirements of tree species assessed in local field studies and in experiments are valid at larger scales across Switzerland.

  2. distributional trends of four species of freshwater snails in south ...

    African Journals Online (AJOL)

    obvious from Maps 3, 4 and 5 that this distributional trend also applies to the larger area. In fact, in many of the .... Thus the series P + L > B + L > P + B obtained in the previous analysis still applies. 4. If all those loci in .... In order to be able to estimate the probability of the occurrence of one genus in a particular area, given ...

  3. The Quercus feeding Stigmella species of the West Palaearctic: new species, key and distribution (Lepidoptera: Nepticulidae)

    NARCIS (Netherlands)

    Nieukerken, van E.J.; Johansson, R.

    2003-01-01

    The species of the Stigmella ruficapitella group occurring in the Western Palaearctic and feeding on Quercus are reviewed. We recognise 19 species, five of which are described as new: Stigmella fasciata sp. n. on Quercus pubescens from Slovenia, Croatia, Greece and Turkey, S. cocciferae sp. n. on Q.

  4. Multiple factors and thresholds explaining fish species distributions in lowland streams

    Directory of Open Access Journals (Sweden)

    Cristina Trigal

    2015-07-01

    Full Text Available Appropriate restoration and conservation measures require a good understanding of the factors limiting the distribution of species, the presence of steep changes in the distribution along environmental gradients and the effect of environmental interactions on species distribution. We used 12 environmental variables describing connectivity, hydrology, climate and stream morphology, to model the distributions of 17 fish species from 2005 Swedish stream sites that were sampled between 2000 and 2011. Modeling was performed using boosted regression trees and random forest, two machine learning techniques to assess the relationship between species distributions and their environment. Temperature, width and connectivity (minimum distance to lake or the sea and water discharge, were the most important variables explaining changes in species distribution at large spatial scales. Response curves of fitted occurrence probabilities along predictors often showed abrupt changes, however, clear threshold effects were difficult to detect. Our results show also differences across species and even in the outcomes of the two algorithms, implying that a simultaneous assessment of multiple species may provide a better signal of ecosystem change than the use of surrogate species.

  5. Updating known distribution models for forecasting climate change impact on endangered species.

    Science.gov (United States)

    Muñoz, Antonio-Román; Márquez, Ana Luz; Real, Raimundo

    2013-01-01

    To plan endangered species conservation and to design adequate management programmes, it is necessary to predict their distributional response to climate change, especially under the current situation of rapid change. However, these predictions are customarily done by relating de novo the distribution of the species with climatic conditions with no regard of previously available knowledge about the factors affecting the species distribution. We propose to take advantage of known species distribution models, but proceeding to update them with the variables yielded by climatic models before projecting them to the future. To exemplify our proposal, the availability of suitable habitat across Spain for the endangered Bonelli's Eagle (Aquila fasciata) was modelled by updating a pre-existing model based on current climate and topography to a combination of different general circulation models and Special Report on Emissions Scenarios. Our results suggested that the main threat for this endangered species would not be climate change, since all forecasting models show that its distribution will be maintained and increased in mainland Spain for all the XXI century. We remark on the importance of linking conservation biology with distribution modelling by updating existing models, frequently available for endangered species, considering all the known factors conditioning the species' distribution, instead of building new models that are based on climate change variables only.

  6. Long-term changes of tree species composition and distribution in Korean mountain forests

    Science.gov (United States)

    Lee, Boknam; Lee, Hoontaek; Cho, Sunhee; Yoon, Jongguk; Park, Jongyoung; Kim, Hyun Seok

    2017-04-01

    Long-term changes in the abundance and distribution of tree species in the temperate forests of South Korea remain poorly understood. We investigated how tree species composition and stand distribution change across temperate mountainous forests using the species composition and DBH size collected over the past 15 years (1998-2012) across 130 permanent forest plots of 0.1 ha in Jiri and Baegun mountains in South Korea. The overall net change of tree communities over the years showed positive in terms of stand density, richness, diversity, and evenness. At the species level, the change of relative species composition has been led by intermediate and shade-tolerant species, such as Quercus mongolica, Carpinus laxiflora, Quercus serrate, Quercus variabilis, Styrax japonicus, Lindera erythrocarpa, and Pinus densiflora and was categorized into five species communities, representing gradual increase or decrease, establishment, extinction, fluctuation of species population. At the community level, the change in species composition appeared to have consistent and directional patterns of increase in the annual rate of change in the mean species traits including species density, pole growth rate, adult growth rate, and adult stature. Based on the additive models, the distribution of species diversity was significantly related to topographical variables including elevation, latitude, longitude, slope, topographic wetness index, and curvature where elevation was the most significant driver, followed by latitude and longitude. However, the change in distribution of species diversity was only significantly influenced by latitude and longitude. This is the first study to reveal the long-term dynamics of change in tree species composition and distribution, which are important to broaden our understanding of temperate mountainous forest ecosystem in South Korea.

  7. Distribution of particulate carbohydrate species in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Bhosle, N.B.; Gopalakrishna, V.V.

    of the ships of the Shipping Corporation of India (SCI) for their help in sampling. This is NIO contribu- tion no. 4498. References Bergamaschi B A, Walters J S and Hedges J 1999 Distri- butions of uronic acids and O-methyl sugars in sinking and sedimentary... carbohydrate species in BOB 155 Dubois M, Gilles K A, Hamilton J K, Rebers P A and Smith F 1956 Colorimetric method for determination of sugars and related substances; Anal. Chem. 28 350–356. Elser J J, Fagan W F, Denno R F, Dobberfuhl D R, Folarin A, Huberty A...

  8. Alien plant species list and distribution for Camdeboo National Park, Eastern Cape Province, South Africa

    Directory of Open Access Journals (Sweden)

    Mmoto L. Masubelele

    2009-01-01

    Full Text Available Protected areas globally are threatened by the potential negative impacts that invasive alien plants pose, and Camdeboo National Park (CNP, South Africa, is no exception. Alien plants have been recorded in the CNP since 1981, before it was proclaimed a national park by South African National Parks in 2005. This is the first publication of a list of alien plants in and around the CNP. Distribution maps of some of the first recorded alien plant species are also presented and discussed. To date, 39 species of alien plants have been recorded, of which 13 are invasive and one is a transformer weed. The majority of alien plant species in the park are herbaceous (39% and succulent (24% species. The most widespread alien plant species in the CNP are Atriplex inflata (= A. lindleyi subsp. inflata, Salsola tragus (= S. australis and cacti species, especially Opuntia ficus-indica. Eradication and control measures that have been used for specific problematic alien plant species are described. Conservation implications: This article represents the first step in managing invasive alien plants and includes the collation of a species list and basic information on their distribution in and around the protected area. This is important for enabling effective monitoring of both new introductions and the distribution of species already present. We present the first species list and distribution information for Camdeboo National Park.

  9. Distribution of Anopheles culicifacies and Detection of its Sibling Species E from Madhya Pradesh: Central India

    Science.gov (United States)

    Sharma, Ajay Kumar; Tyagi, Varun; Singh, Sompal; Veer, Vijay; Agrawal, Om Prakash; Sukumaran, Devanathan

    2014-01-01

    Background: Anopheles culicifacies is an important vector of malaria in Southeast Asia, contributing to almost 70% of malaria cases in India. It exists as a complex of five morphologically indistinguishable species A, B, C, D and E with varied geographical distribution patterns. In India, 8% of the total population of Madhya Pradesh (Central India) contributes about 30% of total malaria cases, 60% of total falciparum cases and 50% of malaria deaths. An. culicifacies is the major malaria vector in this state. Vector control mainly relies on the proper identification and distribution of vector species exists in a particular area. The present study was carried out to identify the distribution of An. culicifacies sibling species in certain endemic district of Central India, Madhya Pradesh. Methods: The An. culicifacies mosquitoes collected from the study districts were identified morphologically. The genomic DNA was isolated from the mosquitoes and subjected to Allele specific PCR targeting D3 domain of 28S ribosomal DNA. Results: The mean prevalence of An. culicifacies during the study period was in the range of 8–120 per man per hour (PMH). From the study areas species B was identified from Jabalpur, Chindwara and Hoshangabad, Species C from Hoshangabad only, Species D from Narsinghpur and Khandwa and sibling species E from Mandla, Chindwara and Hoshangabad respectively. Conclusion: This is the first report to detect species E from Madhya Pradesh region which necessitate for reconsideration of species distribution of each An. culicifacies sibling species that would enable to develop required vector control strategies. PMID:26114132

  10. Geographical Distribution of Taenia asiatica and Related Species

    Science.gov (United States)

    Jeon, Hyeong-Kyu; Rim, Han-Jong

    2009-01-01

    Geographical information of Taenia asiatica is reviewed together with that of T. solium and T. saginata. Current distribution of T. asiatica was found to be mostly from Asian countries: the Republic of Korea, China, Taiwan, Indonesia, and Thailand. Molecular genotypic techniques have found out more countries with T. asiatica from Japan, the Philippines, and Vietnam. Specimens used in this paper were collected from around the world and mostly during international collaboration projects of Korean foundations for parasite control activities (1995-2009) in developing countries. PMID:19885327

  11. Temperature effects on gametophyte life-history traits and geographic distribution of two cryptic kelp species.

    Science.gov (United States)

    Oppliger, L Valeria; Correa, Juan A; Engelen, Aschwin H; Tellier, Florence; Vieira, Vasco; Faugeron, Sylvain; Valero, Myriam; Gomez, Gonzalo; Destombe, Christophe

    2012-01-01

    A major determinant of the geographic distribution of a species is expected to be its physiological response to changing abiotic variables over its range. The range of a species often corresponds to the geographic extent of temperature regimes the organism can physiologically tolerate. Many species have very distinct life history stages that may exhibit different responses to environmental factors. In this study we emphasized the critical role of the haploid microscopic stage (gametophyte) of the life cycle to explain the difference of edge distribution of two related kelp species. Lessonia nigrescens was recently identified as two cryptic species occurring in parapatry along the Chilean coast: one located north and the other south of a biogeographic boundary at latitude 29-30°S. Six life history traits from microscopic stages were identified and estimated under five treatments of temperature in eight locations distributed along the Chilean coast in order to (1) estimate the role of temperature in the present distribution of the two cryptic L. nigrescens species, (2) compare marginal populations to central populations of the two cryptic species. In addition, we created a periodic matrix model to estimate the population growth rate (λ) at the five temperature treatments. Differential tolerance to temperature was demonstrated between the two species, with the gametophytes of the Northern species being more tolerant to higher temperatures than gametophytes from the south. Second, the two species exhibited different life history strategies with a shorter haploid phase in the Northern species contrasted with considerable vegetative growth in the Southern species haploid stage. These results provide strong ecological evidence for the differentiation process of the two cryptic species and show local adaptation of the life cycle at the range limits of the distribution. Ecological and evolutionary implications of these findings are discussed.

  12. Temperature effects on gametophyte life-history traits and geographic distribution of two cryptic kelp species.

    Directory of Open Access Journals (Sweden)

    L Valeria Oppliger

    Full Text Available A major determinant of the geographic distribution of a species is expected to be its physiological response to changing abiotic variables over its range. The range of a species often corresponds to the geographic extent of temperature regimes the organism can physiologically tolerate. Many species have very distinct life history stages that may exhibit different responses to environmental factors. In this study we emphasized the critical role of the haploid microscopic stage (gametophyte of the life cycle to explain the difference of edge distribution of two related kelp species. Lessonia nigrescens was recently identified as two cryptic species occurring in parapatry along the Chilean coast: one located north and the other south of a biogeographic boundary at latitude 29-30°S. Six life history traits from microscopic stages were identified and estimated under five treatments of temperature in eight locations distributed along the Chilean coast in order to (1 estimate the role of temperature in the present distribution of the two cryptic L. nigrescens species, (2 compare marginal populations to central populations of the two cryptic species. In addition, we created a periodic matrix model to estimate the population growth rate (λ at the five temperature treatments. Differential tolerance to temperature was demonstrated between the two species, with the gametophytes of the Northern species being more tolerant to higher temperatures than gametophytes from the south. Second, the two species exhibited different life history strategies with a shorter haploid phase in the Northern species contrasted with considerable vegetative growth in the Southern species haploid stage. These results provide strong ecological evidence for the differentiation process of the two cryptic species and show local adaptation of the life cycle at the range limits of the distribution. Ecological and evolutionary implications of these findings are discussed.

  13. Plant species distribution along environmental gradient: do belowground interactions with fungi matter?

    Directory of Open Access Journals (Sweden)

    Loïc ePellissier

    2013-12-01

    Full Text Available The distribution of plants along environmental gradients is constrained by abiotic and biotic factors. Cumulative evidence attests of the impact of abiotic factors on plant distributions, but only few studies discuss the role of belowground communities. Soil fungi, in particular, are thought to play an important role in how plant species assemble locally into communities. We first review existing evidence, and then test the effect of the number of soil fungal operational taxonomic units (OTUs on plant species distributions using a recently collected dataset of plant and metagenomic information on soil fungi in the Western Swiss Alps. Using species distribution models, we investigated whether the distribution of individual plant species is correlated to the number of OTUs of two important soil fungal classes known to interact with plants: the Glomeromycetes, that are obligatory symbionts of plants, and the Agaricomycetes, that may be facultative plant symbionts, pathogens, or wood decayers. We show that including the fungal richness information in the models of plant species distributions improves predictive accuracy. Number of fungal OTUs is especially correlated to the distribution of high elevation plant species. We suggest that high elevation soil show greater variation in fungal assemblages that may in turn impact plant turnover among communities. We finally discuss how to move beyond correlative analyses, through the design of field experiments manipulating plant and fungal communities along environmental gradients.

  14. Geographical variation in the distribution of different calanid species in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Stephen, R.

    is associated with upwelling was encountered along the Arabian and Somali coasts. This study also indicated occasional surfacing behaviour of C. carinatus. The hydrographical features that restrict the distribution of the above species are highlighted...

  15. Gridded Species Distribution, Version 1: Mammals of the Americas Family Richness Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mammals of the Americas Family Richness Grids of the Gridded Species Distribution, Version 1 are aggregations of the presence grids data at the family level....

  16. Gridded Species Distribution, Version 1: Birds of the Americas Original Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — The Birds of the Americas Original Grids of the Gridded Species Distribution, Version 1are converted 1- kilometer grid cell data in the Geographic Coordinate System...

  17. Loxosceles Heinecken & Lowe, 1835 (Araneae; Sicariidae) species distribution in the State of Paraná

    National Research Council Canada - National Science Library

    Emanuel Marques-da-Silva; Marta Luciane Fischer

    2005-01-01

      The State of Paraná registers on average 2,577 loxoscelic accidents annually. For the elaboration of control and management programs one should first determine the distribution of the species of the genus Loxosceles...

  18. Gridded Species Distribution, Version 1: Birds of the Americas Family Richness Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — The Birds of the Americas Family Richness Grids of the Gridded Species Distribution, Version 1 are the aggregations of the Presence Grids data at the family level....

  19. Gridded Species Distribution, Version 1: Mammals of the Americas Original Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mammals of the Americas Original Grids of the Gridded Species Distribution, Version 1 are converted 1- kilometer grid cell data in the Geographic Coordinate...

  20. Parallel extinction risk and global distribution of languages and species.

    Science.gov (United States)

    Sutherland, William J

    2003-05-15

    There are global threats to biodiversity with current extinction rates well above background levels. Although less well publicized, numerous human languages have also become extinct, and others are threatened with extinction. However, estimates of the number of threatened languages vary considerably owing to the wide range of criteria used. For example, languages have been classified as threatened if the number of speakers is less than 100, 500, 1,000, 10,000, 20,000 or 100,000 (ref. 3). Here I show, by applying internationally agreed criteria for classifying species extinction risk, that languages are more threatened than birds or mammals. Rare languages are more likely to show evidence of decline than commoner ones. Areas with high language diversity also have high bird and mammal diversity and all three show similar relationships to area, latitude, area of forest and, for languages and birds, maximum altitude. The time of human settlement has little effect on current language diversity. Although similar factors explain the diversity of languages and biodiversity, the factors explaining extinction risk for birds and mammals (high altitude, high human densities and insularity) do not explain the numbers of endangered languages.

  1. Species Distribution Modelling: Contrasting presence-only models with plot abundance data

    OpenAIRE

    Gomes, Vitor H. F.; IJff, Stéphanie D.; Raes, Niels; Amaral, Iêda Leão; Salomão, Rafael P.; de Souza Coelho, Luiz; de Almeida Matos, Francisca Dionízia; Castilho, Carolina V.; de Andrade Lima Filho, Diogenes; López, Dairon Cárdenas; Guevara, Juan Ernesto; Magnusson, William E.; Phillips, Oliver L.; Wittmann, Florian; de Jesus Veiga Carim, Marcelo

    2018-01-01

    Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (...

  2. Spatial Distribution of Cryptic Species Diversity in European Freshwater Amphipods (Gammarus fossarum) as Revealed by Pyrosequencing

    OpenAIRE

    Westram, A. M.; Jokela, J.; Baumgartner, C; Keller, I.

    2011-01-01

    In order to understand and protect ecosystems, local gene pools need to be evaluated with respect to their uniqueness. Cryptic species present a challenge in this context because their presence, if unrecognized, may lead to serious misjudgement of the distribution of evolutionarily distinct genetic entities. In this study, we describe the current geographical distribution of cryptic species of the ecologically important stream amphipod Gammarus fossarum (types A, B and C). We use a novel pyro...

  3. On the distribution of Rostkovia magellanica (Juncaceae) - a species newly rediscovered in Ecuador

    DEFF Research Database (Denmark)

    Balslev, Henrik

    1979-01-01

    Rostkovia magellanica has hitherto been considered a species of Patagonia and the subantarctic islands from New Zealand to South Georgia. An old report from Ecuador has been considered erroneous, but it has now been rediscovered there. Brief notes on the ecology of the species are given......, and the possible origin of its distribution is discussed. Long-distance dispersal by birds is suggested as having caused the disjunct distribution on mainland South America....

  4. Model Checking as Static Analysis

    DEFF Research Database (Denmark)

    Zhang, Fuyuan

    to a multi-valued setting, and we therefore obtain a multivalued analysis for temporal properties specied by CTL formulas. In particular, we have shown that the three-valued CTL model checking problem over Kripke modal transition systems can be exactly encoded in three-valued ALFP. Last, we come back to two-valued......Both model checking and static analysis are prominent approaches to detecting software errors. Model Checking is a successful formal method for verifying properties specified in temporal logics with respect to transition systems. Static analysis is also a powerful method for validating program...... properties which can predict safe approximations to program behaviors. In this thesis, we have developed several static analysis based techniques to solve model checking problems, aiming at showing the link between static analysis and model checking. We focus on logical approaches to static analysis...

  5. Linking macroecology and community ecology: refining predictions of species distributions using biotic interaction networks.

    Science.gov (United States)

    Staniczenko, Phillip P A; Sivasubramaniam, Prabu; Suttle, K Blake; Pearson, Richard G

    2017-06-01

    Macroecological models for predicting species distributions usually only include abiotic environmental conditions as explanatory variables, despite knowledge from community ecology that all species are linked to other species through biotic interactions. This disconnect is largely due to the different spatial scales considered by the two sub-disciplines: macroecologists study patterns at large extents and coarse resolutions, while community ecologists focus on small extents and fine resolutions. A general framework for including biotic interactions in macroecological models would help bridge this divide, as it would allow for rigorous testing of the role that biotic interactions play in determining species ranges. Here, we present an approach that combines species distribution models with Bayesian networks, which enables the direct and indirect effects of biotic interactions to be modelled as propagating conditional dependencies among species' presences. We show that including biotic interactions in distribution models for species from a California grassland community results in better range predictions across the western USA. This new approach will be important for improving estimates of species distributions and their dynamics under environmental change. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  6. Digenean parasites of Chinese marine fishes: a list of species, hosts and geographical distribution.

    Science.gov (United States)

    Liu, Sheng-fa; Peng, Wen-feng; Gao, Peng; Fu, Ming-jun; Wu, Han-zhou; Lu, Ming-ke; Gao, Ji-qing; Xiao, Jun

    2010-01-01

    In the literature, 630 species of Digenea (Trematoda) have been reported from Chinese marine fishes. These belong to 209 genera and 35 families. The names of these species, along with their hosts, geographical distribution and records, are listed in this paper.

  7. The importance of data quality for generating reliable distribution models for rare, elusive, and cryptic species

    Science.gov (United States)

    Keith B. Aubry; Catherine M. Raley; Kevin S. McKelvey

    2017-01-01

    The availability of spatially referenced environmental data and species occurrence records in online databases enable practitioners to easily generate species distribution models (SDMs) for a broad array of taxa. Such databases often include occurrence records of unknown reliability, yet little information is available on the influence of data quality on SDMs generated...

  8. Geological Substrates Shape Tree Species and Trait Distributions in African Moist Forests

    Science.gov (United States)

    Fayolle, Adeline; Engelbrecht, Bettina; Freycon, Vincent; Mortier, Frédéric; Swaine, Michael; Réjou-Méchain, Maxime; Doucet, Jean-Louis; Fauvet, Nicolas; Cornu, Guillaume; Gourlet-Fleury, Sylvie

    2012-01-01

    Background Understanding the factors that shape the distribution of tropical tree species at large scales is a central issue in ecology, conservation and forest management. The aims of this study were to (i) assess the importance of environmental factors relative to historical factors for tree species distributions in the semi-evergreen forests of the northern Congo basin; and to (ii) identify potential mechanisms explaining distribution patterns through a trait-based approach. Methodology/Principal Findings We analyzed the distribution patterns of 31 common tree species in an area of more than 700,000 km2 spanning the borders of Cameroon, the Central African Republic, and the Republic of Congo using forest inventory data from 56,445 0.5-ha plots. Spatial variation of environmental (climate, topography and geology) and historical factors (human disturbance) were quantified from maps and satellite records. Four key functional traits (leaf phenology, shade tolerance, wood density, and maximum growth rate) were extracted from the literature. The geological substrate was of major importance for the distribution of the focal species, while climate and past human disturbances had a significant but lesser impact. Species distribution patterns were significantly related to functional traits. Species associated with sandy soils typical of sandstone and alluvium were characterized by slow growth rates, shade tolerance, evergreen leaves, and high wood density, traits allowing persistence on resource-poor soils. In contrast, fast-growing pioneer species rarely occurred on sandy soils, except for Lophira alata. Conclusions/Significance The results indicate strong environmental filtering due to differential soil resource availability across geological substrates. Additionally, long-term human disturbances in resource-rich areas may have accentuated the observed patterns of species and trait distributions. Trait differences across geological substrates imply pronounced

  9. Geological substrates shape tree species and trait distributions in African moist forests.

    Directory of Open Access Journals (Sweden)

    Adeline Fayolle

    Full Text Available BACKGROUND: Understanding the factors that shape the distribution of tropical tree species at large scales is a central issue in ecology, conservation and forest management. The aims of this study were to (i assess the importance of environmental factors relative to historical factors for tree species distributions in the semi-evergreen forests of the northern Congo basin; and to (ii identify potential mechanisms explaining distribution patterns through a trait-based approach. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the distribution patterns of 31 common tree species in an area of more than 700,000 km(2 spanning the borders of Cameroon, the Central African Republic, and the Republic of Congo using forest inventory data from 56,445 0.5-ha plots. Spatial variation of environmental (climate, topography and geology and historical factors (human disturbance were quantified from maps and satellite records. Four key functional traits (leaf phenology, shade tolerance, wood density, and maximum growth rate were extracted from the literature. The geological substrate was of major importance for the distribution of the focal species, while climate and past human disturbances had a significant but lesser impact. Species distribution patterns were significantly related to functional traits. Species associated with sandy soils typical of sandstone and alluvium were characterized by slow growth rates, shade tolerance, evergreen leaves, and high wood density, traits allowing persistence on resource-poor soils. In contrast, fast-growing pioneer species rarely occurred on sandy soils, except for Lophira alata. CONCLUSIONS/SIGNIFICANCE: The results indicate strong environmental filtering due to differential soil resource availability across geological substrates. Additionally, long-term human disturbances in resource-rich areas may have accentuated the observed patterns of species and trait distributions. Trait differences across geological substrates imply

  10. Geological substrates shape tree species and trait distributions in African moist forests.

    Science.gov (United States)

    Fayolle, Adeline; Engelbrecht, Bettina; Freycon, Vincent; Mortier, Frédéric; Swaine, Michael; Réjou-Méchain, Maxime; Doucet, Jean-Louis; Fauvet, Nicolas; Cornu, Guillaume; Gourlet-Fleury, Sylvie

    2012-01-01

    Understanding the factors that shape the distribution of tropical tree species at large scales is a central issue in ecology, conservation and forest management. The aims of this study were to (i) assess the importance of environmental factors relative to historical factors for tree species distributions in the semi-evergreen forests of the northern Congo basin; and to (ii) identify potential mechanisms explaining distribution patterns through a trait-based approach. We analyzed the distribution patterns of 31 common tree species in an area of more than 700,000 km(2) spanning the borders of Cameroon, the Central African Republic, and the Republic of Congo using forest inventory data from 56,445 0.5-ha plots. Spatial variation of environmental (climate, topography and geology) and historical factors (human disturbance) were quantified from maps and satellite records. Four key functional traits (leaf phenology, shade tolerance, wood density, and maximum growth rate) were extracted from the literature. The geological substrate was of major importance for the distribution of the focal species, while climate and past human disturbances had a significant but lesser impact. Species distribution patterns were significantly related to functional traits. Species associated with sandy soils typical of sandstone and alluvium were characterized by slow growth rates, shade tolerance, evergreen leaves, and high wood density, traits allowing persistence on resource-poor soils. In contrast, fast-growing pioneer species rarely occurred on sandy soils, except for Lophira alata. The results indicate strong environmental filtering due to differential soil resource availability across geological substrates. Additionally, long-term human disturbances in resource-rich areas may have accentuated the observed patterns of species and trait distributions. Trait differences across geological substrates imply pronounced differences in population and ecosystem processes, and call for different

  11. The effects of drainage on groundwater quality and plant species distribution in stream valley meadows

    NARCIS (Netherlands)

    Grootjans, A.P.; Diggelen, R. van; Wassen, M.J.; Wiersinga, W.A.

    1988-01-01

    Conditions in fen meadows in Dutch stream valleys are influenced by both deep (Ca2+-rich) and shallow (Ca2+-poor) groundwater flows. The distribution patterns of phreatophytic (groundwater-influenced) plant species showed distinct relationships with the distribution of different groundwater types.

  12. Continental-wide distribution of crayfish species in Europe: update and maps

    Directory of Open Access Journals (Sweden)

    Kouba A.

    2014-01-01

    Full Text Available Recently published astacological studies substantially improved available data on distribution of crayfish in various European regions. At the same time, spread of invasive species has been recorded, additional non-indigenous species became established in various countries, and losses of populations of native species due to crayfish plague and other negative factors were observed. We overview recent advances in this knowledge, and provide updated colour maps of the distribution of all crayfish species present in Europe. These maps are originally based on the data from the Atlas of Crayfish in Europe published in 2006 as a result of the CRAYNET project, and were further updated from more recently published reports, grey literature, and especially thanks to contributions and feedback of over 70 specialists from 32 countries. Separate maps are available for all indigenous crayfish species in Europe as well as for three most widespread non-indigenous crayfish species. Additionally, two maps give locations of known findings of crayfish species introduced to Europe after 1980. These newly established alien species have so far restricted distributions; however, the frequency of recent reports suggests that findings of such species resulting from releases of aquarium pets will further increase.

  13. Predicting plant invasions under climate change: are species distribution models validated by field trials?

    Science.gov (United States)

    Sheppard, Christine S; Burns, Bruce R; Stanley, Margaret C

    2014-09-01

    Climate change may facilitate alien species invasion into new areas, particularly for species from warm native ranges introduced into areas currently marginal for temperature. Although conclusions from modelling approaches and experimental studies are generally similar, combining the two approaches has rarely occurred. The aim of this study was to validate species distribution models by conducting field trials in sites of differing suitability as predicted by the models, thus increasing confidence in their ability to assess invasion risk. Three recently naturalized alien plants in New Zealand were used as study species (Archontophoenix cunninghamiana, Psidium guajava and Schefflera actinophylla): they originate from warm native ranges, are woody bird-dispersed species and of concern as potential weeds. Seedlings were grown in six sites across the country, differing both in climate and suitability (as predicted by the species distribution models). Seedling growth and survival were recorded over two summers and one or two winter seasons, and temperature and precipitation were monitored hourly at each site. Additionally, alien seedling performances were compared to those of closely related native species (Rhopalostylis sapida, Lophomyrtus bullata and Schefflera digitata). Furthermore, half of the seedlings were sprayed with pesticide, to investigate whether enemy release may influence performance. The results showed large differences in growth and survival of the alien species among the six sites. In the more suitable sites, performance was frequently higher compared to the native species. Leaf damage from invertebrate herbivory was low for both alien and native seedlings, with little evidence that the alien species should have an advantage over the native species because of enemy release. Correlations between performance in the field and predicted suitability of species distribution models were generally high. The projected increase in minimum temperature and reduced

  14. Lithologic data improve plant species distribution models based on coarse-grained occurrence data

    Energy Technology Data Exchange (ETDEWEB)

    Gaston, A.; Soriano, C.; Gomez-Miguel, V.

    2009-07-01

    The aim of this study was to assess the improvement of plant species distribution models based on coarse-grained occurrence data when adding lithologic data to climatic models. The distributions of 40 woody plant species from continental Spain were modelled. A logistic regression model with climatic predictors was fitted for each species and compared to a second model with climatic and lithologic predictors. Improvements on model likelihood and prediction accuracy on validation sub samples were assessed, as well as the effect of calcicole calcifuge habit on model improvement. Climatic models had reasonable mean prediction accuracy, but adding lithologic data improved model likelihood in most cases and increased mean prediction accuracy. Therefore, we recommend utilizing lithologic data for species distribution models based on coarse-grained occurrence data. Our data did not support the hypothesis that calcicole calcifuge habit may explain model improvement when adding lithologic data to climatic models, but further research is needed. (Author) 31 refs.

  15. Spatial structures of the environment and of dispersal impact species distribution in competitive metacommunities.

    Science.gov (United States)

    Ai, Dexiecuo; Gravel, Dominique; Chu, Chengjin; Wang, Gang

    2013-01-01

    The correspondence between species distribution and the environment depends on species' ability to track favorable environmental conditions (via dispersal) and to maintain competitive hierarchy against the constant influx of migrants (mass effect) and demographic stochasticity (ecological drift). Here we report a simulation study of the influence of landscape structure on species distribution. We consider lottery competition for space in a spatially heterogeneous environment, where the landscape is represented as a network of localities connected by dispersal. We quantified the contribution of neutrality and species sorting to their spatial distribution. We found that neutrality increases and the strength of species-sorting decreases with the centrality of a community in the landscape when the average dispersal among communities is low, whereas the opposite was found at elevated dispersal. We also found that the strength of species-sorting increases with environmental heterogeneity. Our results illustrate that spatial structure of the environment and of dispersal must be taken into account for understanding species distribution. We stress the importance of spatial geographic structure on the relative importance of niche vs. neutral processes in controlling community dynamics.

  16. Prediction efficiency of the hydrographical parameters as related to distribution patterns of the Pleuromamma species in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Jayalakshmy, K.V.; Saraswathy, M.

    Among species of the genus Pleuromamma, P. indica was the only species existing in the Northern Indian Ocean. In the rest of the Indian Ocean the most abundant species was P. gracilis, and P. abdominalis was almost homogeneously distributed...

  17. Predicting species distribution and abundance responses to climate change: why it is essential to include biotic interactions across trophic levels

    NARCIS (Netherlands)

    Van der Putten, W.H.; Macel, M.; Visser, M.E.

    2010-01-01

    Current predictions on species responses to climate change strongly rely on projecting altered environmental conditions on species distributions. However, it is increasingly acknowledged that climate change also influences species interactions. We review and synthesize literature information on

  18. Vegetation in Bangalore's Slums: Composition, Species Distribution, Density, Diversity, and History

    Science.gov (United States)

    Gopal, Divya; Nagendra, Harini; Manthey, Michael

    2015-06-01

    There is widespread acknowledgement of the need for biodiversity and greening to be part of urban sustainability efforts. Yet we know little about greenery in the context of urban poverty, particularly in slums, which constitute a significant challenge for inclusive development in many rapidly growing cities. We assessed the composition, density, diversity, and species distribution of vegetation in 44 slums of Bangalore, India, comparing these to published studies on vegetation diversity in other land-use categories. Most trees were native to the region, as compared to other land-use categories such as parks and streets which are dominated by introduced species. Of the most frequently encountered tree species, Moringa oleifera and Cocos nucifera are important for food, while Ficus religiosa plays a critical cultural and religious role. Tree density and diversity were much lower in slums compared to richer residential neighborhoods. There are also differences in species preferences, with most plant (herb, shrub and vines) species in slums having economic, food, medicinal, or cultural use, while the species planted in richer residential areas are largely ornamental. Historic development has had an impact on species distribution, with older slums having larger sized tree species, while recent slums were dominated by smaller sized tree species with greater economic and food use. Extensive focus on planting trees and plant species with utility value is required in these congested neighborhoods, to provide livelihood support.

  19. From ratites to rats: the size of fleshy fruits shapes species' distributions and continental rainforest assembly.

    Science.gov (United States)

    Rossetto, Maurizio; Kooyman, Robert; Yap, Jia-Yee S; Laffan, Shawn W

    2015-12-07

    Seed dispersal is a key process in plant spatial dynamics. However, consistently applicable generalizations about dispersal across scales are mostly absent because of the constraints on measuring propagule dispersal distances for many species. Here, we focus on fleshy-fruited taxa, specifically taxa with large fleshy fruits and their dispersers across an entire continental rainforest biome. We compare species-level results of whole-chloroplast DNA analyses in sister taxa with large and small fruits, to regional plot-based samples (310 plots), and whole-continent patterns for the distribution of woody species with either large (more than 30 mm) or smaller fleshy fruits (1093 taxa). The pairwise genomic comparison found higher genetic distances between populations and between regions in the large-fruited species (Endiandra globosa), but higher overall diversity within the small-fruited species (Endiandra discolor). Floristic comparisons among plots confirmed lower numbers of large-fruited species in areas where more extreme rainforest contraction occurred, and re-colonization by small-fruited species readily dispersed by the available fauna. Species' distribution patterns showed that larger-fruited species had smaller geographical ranges than smaller-fruited species and locations with stable refugia (and high endemism) aligned with concentrations of large fleshy-fruited taxa, making them a potentially valuable conservation-planning indicator. © 2015 The Author(s).

  20. Species distributions models in wildlife planning: agricultural policy and wildlife management in the great plains

    Science.gov (United States)

    Fontaine, Joseph J.; Jorgensen, Christopher; Stuber, Erica F.; Gruber, Lutz F.; Bishop, Andrew A.; Lusk, Jeffrey J.; Zach, Eric S.; Decker, Karie L.

    2017-01-01

    We know economic and social policy has implications for ecosystems at large, but the consequences for a given geographic area or specific wildlife population are more difficult to conceptualize and communicate. Species distribution models, which extrapolate species-habitat relationships across ecological scales, are capable of predicting population changes in distribution and abundance in response to management and policy, and thus, are an ideal means for facilitating proactive management within a larger policy framework. To illustrate the capabilities of species distribution modeling in scenario planning for wildlife populations, we projected an existing distribution model for ring-necked pheasants (Phasianus colchicus) onto a series of alternative future landscape scenarios for Nebraska, USA. Based on our scenarios, we qualitatively and quantitatively estimated the effects of agricultural policy decisions on pheasant populations across Nebraska, in specific management regions, and at wildlife management areas. 

  1. Determinants of geographical distribution in Atlantic Forest species of Drymophila (Aves: Thamnophilidae

    Directory of Open Access Journals (Sweden)

    Henrique Rajão

    2010-02-01

    Full Text Available Climate, altitude and vegetation are usually considered as limiting factors in plant and animal distribution. Among vertebrates, climate and vegetation have consistently been considered as major determinants of geographical distributions. Here we analyzed the role of climate and the vegetation in limiting the geographical range of Atlantic Forest species of Drymophila Swainson, 1824 and assessed the performance of discriminant analysis to model the distribution of sympatric taxa. From each empirical point (locality we recorded the values for nine climatic variables and the type of vegetation. The climatic data were obtained from a climate database elaborated by the Laboratório de Vertebrados and vegetation data from the ecoregions digital map of Latin America. The overlap of the climatic distribution map with the ecoregion map suggested that both factors are important in limiting the geographical range of Drymophila species. The discriminant approach, as applied here, was not satisfactory when compared with similar analysis carried out on parapatric species.

  2. The role of demography, intra-species variation, and species distribution models in species’ projections under climate change

    DEFF Research Database (Denmark)

    Swab, Rebecca Marie; Regan, Helen M.; Matthies, Diethart

    2015-01-01

    and linked it to a SDM that predicted changes in habitat suitability through time with changes in climatic variables. We then varied the demographic parameters based upon observed vital rates of local populations from a translocation experiment. Despite the fact that the SDM alone predicted C. vulgaris......Organisms are projected to shift their distribution ranges under climate change. The typical way to assess range shifts is by species distribution models (SDMs), which predict species’ responses to climate based solely on projected climatic suitability. However, life history traits can impact...... species’ responses to shifting habitat suitability. Additionally, it remains unclear if differences in vital rates across populations within a species can offset or exacerbate the effects of predicted changes in climatic suitability on population viability. In order to obtain a fuller understanding...

  3. A new species of Austrolebias Costa (Cyprinodontiformes: Rivulidae from northeastern Uruguay, with comments on distribution patterns

    Directory of Open Access Journals (Sweden)

    Marcelo Loureiro

    Full Text Available A new species of Austrolebias is described based on individuals from the middle and upper río Negro (río Uruguay basin and río Yaguarón (Patos-Merín system. The new species can be differentiated from all other species of the genus by the unique presence in males of uniform bluish gray pigmentation on flanks (without vertical bands and unpaired fins. The new species is also distinguished by the combination of characters associated with a reduction of the squamation of the abdominal, preopercular, and opercular regions. The new species presents some morphological characteristics similar to A. gymnoventris and A. luteoflammulatus. The distribution of the new species is concordant with three other species of Austrolebias and may represent a case of drainage rearrangement of the río Negro upstream tributaries (río Uruguay basin and tributaries of laguna Merín system.

  4. Spatial distribution, Leishmania species and clinical traits of Cutaneous Leishmaniasis cases in the Colombian army.

    Science.gov (United States)

    Patino, Luz H; Mendez, Claudia; Rodriguez, Omaira; Romero, Yanira; Velandia, Daniel; Alvarado, Maria; Pérez, Julie; Duque, Maria Clara; Ramírez, Juan David

    2017-08-01

    In Colombia, the cutaneous leishmaniasis (CL) is the most common manifestation across the army personnel. Hence, it is mandatory to determine the species associated with the disease as well as the association with the clinical traits. A total of 273 samples of male patients with CL were included in the study and clinical data of the patients was studied. PCR and sequencing analyses (Cytb and HSP70 genes) were performed to identify the species and the intra-specific genetic variability. A georeferenced database was constructed to identify the spatial distribution of Leishmania species isolated. The identification of five species of Leishmania that circulate in the areas where army personnel are deployed is described. Predominant infecting Leishmania species corresponds to L. braziliensis (61.1%), followed by Leishmania panamensis (33.5%), with a high distribution of both species at geographical and municipal level. The species L. guyanensis, L. mexicana and L. lainsoni were also detected at lower frequency. We also showed the identification of different genotypes within L. braziliensis and L. panamensis. In conclusion, we identified the Leishmania species circulating in the areas where Colombian army personnel are deployed, as well as the high intra-specific genetic variability of L. braziliensis and L. panamensis and how these genotypes are distributed at the geographic level.

  5. Night Distribution Of Certain Species Of Coleoptera As Indicated By Captures In A Light Trap At Quena

    OpenAIRE

    Hamad, Nor El Din [نور الدين فرغلي حمد; Aly, Mohammed Zaky J.

    1984-01-01

    The night distribution of nineteen species over a whole trapping period can be considered under the following headings: a. Early flyers b. Species with two peaks of activity. The effect of light of low intensity, temperature and humidity on the activity of those species is discussed. c. Species with three peaks of activity. The night distribution of above mentioned species has been compared in each group of the nights. a. Species with one peak in group A and two in group B. Thi...

  6. Spatial distribution and interspecific associations of tree species in a tropical seasonal rain forest of China.

    Directory of Open Access Journals (Sweden)

    Guoyu Lan

    Full Text Available Studying the spatial pattern and interspecific associations of plant species may provide valuable insights into processes and mechanisms that maintain species coexistence. Point pattern analysis was used to analyze the spatial distribution patterns of twenty dominant tree species, their interspecific spatial associations and changes across life stages in a 20-ha permanent plot of seasonal tropical rainforest in Xishuangbanna, China, to test mechanisms maintaining species coexistence. Torus-translation tests were used to quantify positive or negative associations of the species to topographic habitats. The results showed: (1 fourteen of the twenty tree species were negatively (or positively associated with one or two of the topographic variables, which evidences that the niche contributes to the spatial pattern of these species. (2 Most saplings of the study species showed a significantly clumped distribution at small scales (0-10 m which was lost at larger scales (10-30 m. (3 The degree of spatial clumping deceases from saplings, to poles, to adults indicates that density-dependent mortality of the offspring is ubiquitous in species. (4 It is notable that a high number of positive small-scale interactions were found among the twenty species. For saplings, 42.6% of all combinations of species pairs showed positive associations at neighborhood scales up to five meters, but only 38.4% were negative. For poles and adults, positive associations at these distances still made up 45.5% and 29.5%, respectively. In conclusion, there is considerable evidence for the presence of positive interactions among the tree species, which suggests that species herd protection may occur in our plot. In addition, niche assembly and limited dispersal (likely contribute to the spatial patterns of tree species in the tropical seasonal rain forest in Xishuangbanna, China.

  7. New species of Heteropathes (Anthozoa: Antipatharia) expands genus distribution to the NE Atlantic.

    Science.gov (United States)

    De Matos, Valentina; Braga-Henriques, Andreia; Santos, Ricardo S; Ribeiro, Pedro A

    2014-07-03

    Heteropathes opreski, a new antipatharian species from the northern border of the Oceanographer Fracture Zone is here described and illustrated. An emended diagnosis of the genus and a dichotomous key containing the four Heteropathes species are presented. This species is unique in that it forms smaller colonies compared to the other species in the genus, with some of the lateral pinnules presenting a small ramified subpinnule. Additionally, the polypar spines found on the lateral pinnules are the highest so far recorded in the genus. This record greatly expands the known distribution of this genus, as it was not previously reported to occur in the Northeastern Atlantic.

  8. Environmental niche divergence among three dune shrub sister species with parapatric distributions.

    Science.gov (United States)

    Chozas, Sergio; Chefaoui, Rosa M; Correia, Otília; Bonal, Raúl; Hortal, Joaquín

    2017-05-01

    The geographical distributions of species are constrained by their ecological requirements. The aim of this work was to analyse the effects of environmental conditions, historical events and biogeographical constraints on the diversification of the three species of the western Mediterranean shrub genus Stauracanthus , which have a parapatric distribution in the Iberian Peninsula. Ecological niche factor analysis and generalized linear models were used to measure the response of all Stauracanthus species to the environmental gradients and map their potential distributions in the Iberian Peninsula. The bioclimatic niche overlap between the three species was determined by using Schoener's index. The genetic differentiation of the Iberian and northern African populations of Stauracanthus species was characterized with GenalEx. The effects on genetic distances of the most important environmental drivers were assessed through Mantel tests and non-metric multidimensional scaling. The three Stauracanthus species show remarkably similar responses to climatic conditions. This supports the idea that all members of this recently diversified clade retain common adaptations to climate and consequently high levels of climatic niche overlap. This contrasts with the diverse edaphic requirements of Stauracanthus species. The populations of the S. genistoides-spectabilis clade grow on Miocene and Pliocene fine-textured sedimentary soils, whereas S. boivinii , the more genetically distant species, occurs on older and more coarse-textured sedimentary substrates. These patterns of diversification are largely consistent with a stochastic process of geographical range expansion and fragmentation coupled with niche evolution in the context of spatially complex environmental fluctuations. : The combined analysis of the distribution, realized environmental niche and phylogeographical relationships of parapatric species proposed in this work allows integration of the biogeographical

  9. Chemosymbiotic species from the Gulf of Cadiz (NE Atlantic: distribution, life styles and nutritional patterns

    Directory of Open Access Journals (Sweden)

    C. F. Rodrigues

    2013-04-01

    Full Text Available Previous work in the mud volcanoes from the Gulf of Cadiz (South Iberian Margin revealed a high number of chemosymbiotic species, namely bivalves and siboglinid polychaetes. In this study we give an overview of the distribution and life styles of these species in the Gulf of Cadiz, determine the role of autotrophic symbionts in the nutrition of selected species using stable isotope analyses (δ13C, δ15N and δ34S and investigate the intra-specific variation of isotope signatures within and between study sites. During our studies, we identified twenty siboglinidae and nine bivalve chemosymbiotic species living in fifteen mud volcanoes. Solemyid bivalves and tubeworms of the genus Siboglinum are widespread in the study area, whereas other species were found in a single mud volcano (e.g. "Bathymodiolus" mauritanicus or restricted to deeper mud volcanoes (e.g. Polybrachia sp., Lamelisabella denticulata. Species distribution suggests that different species may adjust their position within the sediment according to their particular needs, and to the intensity and variability of the chemical substrata supply. Tissue stable isotope signatures for selected species are in accordance with values found in other studies, with thiotrophy as the dominant nutritional pathway, and with methanotrophy and mixotrophy emerging as secondary strategies. The heterogeneity in terms of nutrient sources (expressed in the high variance of nitrogen and sulphur values and the ability to exploit different resources by the different species may explain the high diversity of chemosymbiotic species found in the Gulf of Cadiz. This study increases the knowledge on distributional patterns and resource partitioning of chemosymbiotic species and highlights how trophic fuelling varies on spatial scales with direct implications to seep assemblages and potentially to the biodiversity of continental margin.

  10. Estimating the spatial and temporal distribution of species richness within Sequoia and Kings Canyon National Parks.

    Science.gov (United States)

    Wathen, Steve; Thorne, James H; Holguin, Andrew; Schwartz, Mark W

    2014-01-01

    Evidence for significant losses of species richness or biodiversity, even within protected natural areas, is mounting. Managers are increasingly being asked to monitor biodiversity, yet estimating biodiversity is often prohibitively expensive. As a cost-effective option, we estimated the spatial and temporal distribution of species richness for four taxonomic groups (birds, mammals, herpetofauna (reptiles and amphibians), and plants) within Sequoia and Kings Canyon National Parks using only existing biological studies undertaken within the Parks and the Parks' long-term wildlife observation database. We used a rarefaction approach to model species richness for the four taxonomic groups and analyzed those groups by habitat type, elevation zone, and time period. We then mapped the spatial distributions of species richness values for the four taxonomic groups, as well as total species richness, for the Parks. We also estimated changes in species richness for birds, mammals, and herpetofauna since 1980. The modeled patterns of species richness either peaked at mid elevations (mammals, plants, and total species richness) or declined consistently with increasing elevation (herpetofauna and birds). Plants reached maximum species richness values at much higher elevations than did vertebrate taxa, and non-flying mammals reached maximum species richness values at higher elevations than did birds. Alpine plant communities, including sagebrush, had higher species richness values than did subalpine plant communities located below them in elevation. These results are supported by other papers published in the scientific literature. Perhaps reflecting climate change: birds and herpetofauna displayed declines in species richness since 1980 at low and middle elevations and mammals displayed declines in species richness since 1980 at all elevations.

  11. Estimating the spatial and temporal distribution of species richness within Sequoia and Kings Canyon National Parks.

    Directory of Open Access Journals (Sweden)

    Steve Wathen

    Full Text Available Evidence for significant losses of species richness or biodiversity, even within protected natural areas, is mounting. Managers are increasingly being asked to monitor biodiversity, yet estimating biodiversity is often prohibitively expensive. As a cost-effective option, we estimated the spatial and temporal distribution of species richness for four taxonomic groups (birds, mammals, herpetofauna (reptiles and amphibians, and plants within Sequoia and Kings Canyon National Parks using only existing biological studies undertaken within the Parks and the Parks' long-term wildlife observation database. We used a rarefaction approach to model species richness for the four taxonomic groups and analyzed those groups by habitat type, elevation zone, and time period. We then mapped the spatial distributions of species richness values for the four taxonomic groups, as well as total species richness, for the Parks. We also estimated changes in species richness for birds, mammals, and herpetofauna since 1980. The modeled patterns of species richness either peaked at mid elevations (mammals, plants, and total species richness or declined consistently with increasing elevation (herpetofauna and birds. Plants reached maximum species richness values at much higher elevations than did vertebrate taxa, and non-flying mammals reached maximum species richness values at higher elevations than did birds. Alpine plant communities, including sagebrush, had higher species richness values than did subalpine plant communities located below them in elevation. These results are supported by other papers published in the scientific literature. Perhaps reflecting climate change: birds and herpetofauna displayed declines in species richness since 1980 at low and middle elevations and mammals displayed declines in species richness since 1980 at all elevations.

  12. A tool for simulating and communicating uncertainty when modelling species distributions under future climates.

    Science.gov (United States)

    Gould, Susan F; Beeton, Nicholas J; Harris, Rebecca M B; Hutchinson, Michael F; Lechner, Alex M; Porfirio, Luciana L; Mackey, Brendan G

    2014-12-01

    Tools for exploring and communicating the impact of uncertainty on spatial prediction are urgently needed, particularly when projecting species distributions to future conditions.We provide a tool for simulating uncertainty, focusing on uncertainty due to data quality. We illustrate the use of the tool using a Tasmanian endemic species as a case study. Our simulations provide probabilistic, spatially explicit illustrations of the impact of uncertainty on model projections. We also illustrate differences in model projections using six different global climate models and two contrasting emissions scenarios.Our case study results illustrate how different sources of uncertainty have different impacts on model output and how the geographic distribution of uncertainty can vary.Synthesis and applications: We provide a conceptual framework for understanding sources of uncertainty based on a review of potential sources of uncertainty in species distribution modelling; a tool for simulating uncertainty in species distribution models; and protocols for dealing with uncertainty due to climate models and emissions scenarios. Our tool provides a step forward in understanding and communicating the impacts of uncertainty on species distribution models under future climates which will be particularly helpful for informing discussions between researchers, policy makers, and conservation practitioners.

  13. Mycorrhizal specificity does not limit the distribution of an endangered orchid species.

    Science.gov (United States)

    Waud, Michael; Brys, Rein; Van Landuyt, Wouter; Lievens, Bart; Jacquemyn, Hans

    2017-03-01

    What factors determine the distribution of a species is a central question in ecology and conservation biology. In general, the distribution of plant species is assumed to be controlled by dispersal or environmentally controlled recruitment. For plant species which are critically dependent on mycorrhizal symbionts for germination and seedling establishment, specificity in mycorrhizal associations and availability of suitable mycorrhizal fungi can be expected to have a major impact on successful colonization and establishment and thus ultimately on a species distribution. We combined seed germination experiments with soil analyses and fungal assessments using 454 amplicon pyrosequencing to test the relative importance of dispersal limitation, mycorrhizal availability and local growth conditions on the distribution of the orchid species Liparis loeselii, which, despite being widely distributed, is rare and endangered in Europe. We compared local soil conditions, seed germination and mycorrhizal availability in the soil between locations in northern Belgium and France where L. loeselii occurs naturally and locations where conditions appear suitable, but where adults of the species are absent. Our results indicated that mycorrhizal communities associating with L. loeselii varied among sites and plant life cycle stages, but the observed variations did not affect seed germination, which occurred regardless of current L. loeselii presence and was significantly affected by soil moisture content. These results indicate that L. loeselii is a mycorrhizal generalist capable of opportunistically associating with a variety of fungal partners to induce seed germination. They also indicate that availability of fungal associates is not necessarily the determining factor driving the distribution of mycorrhizal plant species. © 2017 John Wiley & Sons Ltd.

  14. Multi-scale approach for predicting fish species distributions across coral reef seascapes.

    Directory of Open Access Journals (Sweden)

    Simon J Pittman

    Full Text Available Two of the major limitations to effective management of coral reef ecosystems are a lack of information on the spatial distribution of marine species and a paucity of data on the interacting environmental variables that drive distributional patterns. Advances in marine remote sensing, together with the novel integration of landscape ecology and advanced niche modelling techniques provide an unprecedented opportunity to reliably model and map marine species distributions across many kilometres of coral reef ecosystems. We developed a multi-scale approach using three-dimensional seafloor morphology and across-shelf location to predict spatial distributions for five common Caribbean fish species. Seascape topography was quantified from high resolution bathymetry at five spatial scales (5-300 m radii surrounding fish survey sites. Model performance and map accuracy was assessed for two high performing machine-learning algorithms: Boosted Regression Trees (BRT and Maximum Entropy Species Distribution Modelling (MaxEnt. The three most important predictors were geographical location across the shelf, followed by a measure of topographic complexity. Predictor contribution differed among species, yet rarely changed across spatial scales. BRT provided 'outstanding' model predictions (AUC = >0.9 for three of five fish species. MaxEnt provided 'outstanding' model predictions for two of five species, with the remaining three models considered 'excellent' (AUC = 0.8-0.9. In contrast, MaxEnt spatial predictions were markedly more accurate (92% map accuracy than BRT (68% map accuracy. We demonstrate that reliable spatial predictions for a range of key fish species can be achieved by modelling the interaction between the geographical location across the shelf and the topographic heterogeneity of seafloor structure. This multi-scale, analytic approach is an important new cost-effective tool to accurately delineate essential fish habitat and support

  15. The role of environmental variables in structuring landscape-scale species distributions in seafloor habitats.

    Science.gov (United States)

    Kraan, Casper; Aarts, Geert; Van der Meer, Jaap; Piersma, Theunis

    2010-06-01

    Ongoing statistical sophistication allows a shift from describing species' spatial distributions toward statistically disentangling the possible roles of environmental variables in shaping species distributions. Based on a landscape-scale benthic survey in the Dutch Wadden Sea, we show the merits of spatially explicit generalized estimating equations (GEE). The intertidal macrozoobenthic species, Macoma balthica, Cerastoderma edule, Marenzelleria viridis, Scoloplos armiger, Corophium volutator, and Urothoe poseidonis served as test cases, with median grain-size and inundation time as typical environmental explanatory variables. GEEs outperformed spatially naive generalized linear models (GLMs), and removed much residual spatial structure, indicating the importance of median grain-size and inundation time in shaping landscape-scale species distributions in the intertidal. GEE regression coefficients were smaller than those attained with GLM, and GEE standard errors were larger. The best fitting GEE for each species was used to predict species' density in relation to median grain-size and inundation time. Although no drastic changes were noted compared to previous work that described habitat suitability for benthic fauna in the Wadden Sea, our predictions provided more detailed and unbiased estimates of the determinants of species-environment relationships. We conclude that spatial GEEs offer the necessary methodological advances to further steps toward linking pattern to process.

  16. Species abundance in a forest community in South China: A case of poisson lognormal distribution

    Science.gov (United States)

    Yin, Z.-Y.; Ren, H.; Zhang, Q.-M.; Peng, S.-L.; Guo, Q.-F.; Zhou, G.-Y.

    2005-01-01

    Case studies on Poisson lognormal distribution of species abundance have been rare, especially in forest communities. We propose a numerical method to fit the Poisson lognormal to the species abundance data at an evergreen mixed forest in the Dinghushan Biosphere Reserve, South China. Plants in the tree, shrub and herb layers in 25 quadrats of 20 m??20 m, 5 m??5 m, and 1 m??1 m were surveyed. Results indicated that: (i) for each layer, the observed species abundance with a similarly small median, mode, and a variance larger than the mean was reverse J-shaped and followed well the zero-truncated Poisson lognormal; (ii) the coefficient of variation, skewness and kurtosis of abundance, and two Poisson lognormal parameters (?? and ??) for shrub layer were closer to those for the herb layer than those for the tree layer; and (iii) from the tree to the shrub to the herb layer, the ?? and the coefficient of variation decreased, whereas diversity increased. We suggest that: (i) the species abundance distributions in the three layers reflects the overall community characteristics; (ii) the Poisson lognormal can describe the species abundance distribution in diverse communities with a few abundant species but many rare species; and (iii) 1/?? should be an alternative measure of diversity.

  17. Species Abundance Distribution of Ectoparasites on Norway Rats (Rattus norvegicus) from a Localized Area in Southwest China.

    Science.gov (United States)

    Guo, Xian Guo; Dong, Wen Ge; Men, Xing Yuan; Qian, Ti Jun; Wu, Dian; Ren, Tian Guang; Qin, Feng; Song, Wen Yu; Yang, Zhi Hua; Fletcher, Quinn E

    2016-06-01

    The species of ectoparasites that live on a specific host in a geographical region form an ectoparasite community. Species abundance distributions describe the number of individuals observed for each different species that is encountered within a community. Based on properties of the species abundance distribution, the expected total number of species present in the community can be estimated. Preston's lognormal distribution model was used to fit the expected species abundance distribution curve. Using the expected species abundance distribution curve, we estimated the total number of expected parasite species present and the amount of species that were likely missed by our sampling in the field. In total, 8040 ectoparasites (fleas, sucking lice, gamasid mites and chigger mites) were collected from 431 Norway rats (Rattus norvegicus) from a localized area in southwest China. These ectoparasites were identified to be 47 species from 26 genera in 10 families. The majority of ectoparasite species were chigger mites (family Trombiculidae) while the majority of individuals were sucking lice in the family Polyplacidae. The expected species abundance distribution curve demonstrated the classic pattern that the majority of ectoparasite species were rare and that there were a few common species. The total expected number of ectoparasite species on R. norvegicus was estimated to be 85 species, and 38 species were likely missed by our sampling in the field. Norway rats harbor a large suite of ectoparasites. Future field investigations should sample large numbers of host individuals to assess ectoparasite populations.

  18. Using species abundance distribution models and diversity indices for biogeographical analyses

    Science.gov (United States)

    Fattorini, Simone; Rigal, François; Cardoso, Pedro; Borges, Paulo A. V.

    2016-01-01

    We examine whether Species Abundance Distribution models (SADs) and diversity indices can describe how species colonization status influences species community assembly on oceanic islands. Our hypothesis is that, because of the lack of source-sink dynamics at the archipelago scale, Single Island Endemics (SIEs), i.e. endemic species restricted to only one island, should be represented by few rare species and consequently have abundance patterns that differ from those of more widespread species. To test our hypothesis, we used arthropod data from the Azorean archipelago (North Atlantic). We divided the species into three colonization categories: SIEs, archipelagic endemics (AZEs, present in at least two islands) and native non-endemics (NATs). For each category, we modelled rank-abundance plots using both the geometric series and the Gambin model, a measure of distributional amplitude. We also calculated Shannon entropy and Buzas and Gibson's evenness. We show that the slopes of the regression lines modelling SADs were significantly higher for SIEs, which indicates a relative predominance of a few highly abundant species and a lack of rare species, which also depresses diversity indices. This may be a consequence of two factors: (i) some forest specialist SIEs may be at advantage over other, less adapted species; (ii) the entire populations of SIEs are by definition concentrated on a single island, without possibility for inter-island source-sink dynamics; hence all populations must have a minimum number of individuals to survive natural, often unpredictable, fluctuations. These findings are supported by higher values of the α parameter of the Gambin mode for SIEs. In contrast, AZEs and NATs had lower regression slopes, lower α but higher diversity indices, resulting from their widespread distribution over several islands. We conclude that these differences in the SAD models and diversity indices demonstrate that the study of these metrics is useful for

  19. Vertical distribution and migration of euphausiid species in the Red Sea

    KAUST Repository

    Wiebe, Peter H.

    2016-06-01

    We addressed how the extreme environmental conditions of the Red Sea impact or alter patterns of vertical distribution and vertical migration of five euphausiid species that are known from other oceans. Euphausia diomedeae was abundant and performed diel vertical migration (DVM) from >200 m in daytime to <100 m at night, similar to its pattern in other ocean regions. Euphausia sibogae and Euphausia sanzoi also showed consistent patterns of DVM across their ranges in the Red Sea and elsewhere. Two species, Stylocheiron affine and Stylocheiron abbreviatum, did not exhibit DVM. DNA barcode sequences for mitochondrial cytochrome oxidase I (COI) were used to confirm species identifications for four species (no previous barcode data exist for E. sanzoi). COI sequence differences averaged 2.8% (SD 3.1%) within species and 16.6% (SD 0.7%) between species, similar to previous studies of euphausiids. Red Sea specimens of S. affine matched morphological descriptions of a western equatorial form and differed 14% from Atlantic and Pacific specimens, suggesting possible cryptic species-level variation within this taxon. Widely distributed species of zooplankton may exhibit broad tolerance ranges for key environmental variables, and have considerable potential to adapt to variable and changing conditions across their geographic range.

  20. Species Distribution Models and Ecological Suitability Analysis for Potential Tick Vectors of Lyme Disease in Mexico

    Directory of Open Access Journals (Sweden)

    Patricia Illoldi-Rangel

    2012-01-01

    Full Text Available Species distribution models were constructed for ten Ixodes species and Amblyomma cajennense for a region including Mexico and Texas. The model was based on a maximum entropy algorithm that used environmental layers to predict the relative probability of presence for each taxon. For Mexico, species geographic ranges were predicted by restricting the models to cells which have a higher probability than the lowest probability of the cells in which a presence record was located. There was spatial nonconcordance between the distributions of Amblyomma cajennense and the Ixodes group with the former restricted to lowlands and mainly the eastern coast of Mexico and the latter to montane regions with lower temperature. The risk of Lyme disease is, therefore, mainly present in the highlands where some Ixodes species are known vectors; if Amblyomma cajennense turns out to be a competent vector, the area of risk also extends to the lowlands and the east coast.

  1. Notes on the Chilean geographic distribution of several vascular plant species

    OpenAIRE

    Pfanzelt, Simon; García, Carolina; Marticorena, Alicia

    2013-01-01

    New collections extend the Chilean geographic distributions of five native and one endemic vascular plant species: Coriaria ruscifolia L. (Coriariaceae), Fascicularia bicolor (Ruiz and Pav.) Mez subsp. canaliculata E.C. Nelson and Zizka (Bromeliaceae), Drapetes muscosus Lam. (Thymelaeaceae), Phyllachne uliginosa J.R. Forst. and G. Forst (Stylidiaceae), Saxifragella bicuspidata (Hook.f.) Engl., and Saxifragodes albowiana (Kurtz ex Albov) D.M. Moore (both Saxifragaceae). Species descriptions, d...

  2. Quantifying shark distribution patterns and species-habitat associations: implications of marine park zoning.

    Science.gov (United States)

    Espinoza, Mario; Cappo, Mike; Heupel, Michelle R; Tobin, Andrew J; Simpfendorfer, Colin A

    2014-01-01

    Quantifying shark distribution patterns and species-specific habitat associations in response to geographic and environmental drivers is critical to assessing risk of exposure to fishing, habitat degradation, and the effects of climate change. The present study examined shark distribution patterns, species-habitat associations, and marine reserve use with baited remote underwater video stations (BRUVS) along the entire Great Barrier Reef Marine Park (GBRMP) over a ten year period. Overall, 21 species of sharks from five families and two orders were recorded. Grey reef Carcharhinus amblyrhynchos, silvertip C. albimarginatus, tiger Galeocerdo cuvier, and sliteye Loxodon macrorhinus sharks were the most abundant species (>64% of shark abundances). Multivariate regression trees showed that hard coral cover produced the primary split separating shark assemblages. Four indicator species had consistently higher abundances and contributed to explaining most of the differences in shark assemblages: C. amblyrhynchos, C. albimarginatus, G. cuvier, and whitetip reef Triaenodon obesus sharks. Relative distance along the GBRMP had the greatest influence on shark occurrence and species richness, which increased at both ends of the sampling range (southern and northern sites) relative to intermediate latitudes. Hard coral cover and distance across the shelf were also important predictors of shark distribution. The relative abundance of sharks was significantly higher in non-fished sites, highlighting the conservation value and benefits of the GBRMP zoning. However, our results also showed that hard coral cover had a large effect on the abundance of reef-associated shark species, indicating that coral reef health may be important for the success of marine protected areas. Therefore, understanding shark distribution patterns, species-habitat associations, and the drivers responsible for those patterns is essential for developing sound management and conservation approaches.

  3. Quantifying shark distribution patterns and species-habitat associations: implications of marine park zoning.

    Directory of Open Access Journals (Sweden)

    Mario Espinoza

    Full Text Available Quantifying shark distribution patterns and species-specific habitat associations in response to geographic and environmental drivers is critical to assessing risk of exposure to fishing, habitat degradation, and the effects of climate change. The present study examined shark distribution patterns, species-habitat associations, and marine reserve use with baited remote underwater video stations (BRUVS along the entire Great Barrier Reef Marine Park (GBRMP over a ten year period. Overall, 21 species of sharks from five families and two orders were recorded. Grey reef Carcharhinus amblyrhynchos, silvertip C. albimarginatus, tiger Galeocerdo cuvier, and sliteye Loxodon macrorhinus sharks were the most abundant species (>64% of shark abundances. Multivariate regression trees showed that hard coral cover produced the primary split separating shark assemblages. Four indicator species had consistently higher abundances and contributed to explaining most of the differences in shark assemblages: C. amblyrhynchos, C. albimarginatus, G. cuvier, and whitetip reef Triaenodon obesus sharks. Relative distance along the GBRMP had the greatest influence on shark occurrence and species richness, which increased at both ends of the sampling range (southern and northern sites relative to intermediate latitudes. Hard coral cover and distance across the shelf were also important predictors of shark distribution. The relative abundance of sharks was significantly higher in non-fished sites, highlighting the conservation value and benefits of the GBRMP zoning. However, our results also showed that hard coral cover had a large effect on the abundance of reef-associated shark species, indicating that coral reef health may be important for the success of marine protected areas. Therefore, understanding shark distribution patterns, species-habitat associations, and the drivers responsible for those patterns is essential for developing sound management and conservation

  4. The Classification of the Salvia L. (Labiatae) Species Distributed in West Anatolia According to Phenolic Compounds

    OpenAIRE

    NAKİBOĞLU, Mahmure

    2014-01-01

    The seven species of Salvia L. growing naturally in West Anatolia (Salvia tomentosa Mill., Salvia fruticosa Mill., Salvia smyrnaea Boiss., Salvia argentea L., Salvia horminum L., Salvia verbenaca L., and Salvia virgata Jacq.) and a cultivated form (Salvia officinalis L.) were selected as the study materials. The phenolic compounds extracted from the leaves of the species were separated by two- dimensional thin-layer chromatography. On the basis of the distribution of phenolic spots in the spe...

  5. Adaptive invasive species distribution models: A framework for modeling incipient invasions

    Science.gov (United States)

    Uden, Daniel R.; Allen, Craig R.; Angeler, David G.; Corral, Lucia; Fricke, Kent A.

    2015-01-01

    The utilization of species distribution model(s) (SDM) for approximating, explaining, and predicting changes in species’ geographic locations is increasingly promoted for proactive ecological management. Although frameworks for modeling non-invasive species distributions are relatively well developed, their counterparts for invasive species—which may not be at equilibrium within recipient environments and often exhibit rapid transformations—are lacking. Additionally, adaptive ecological management strategies address the causes and effects of biological invasions and other complex issues in social-ecological systems. We conducted a review of biological invasions, species distribution models, and adaptive practices in ecological management, and developed a framework for adaptive, niche-based, invasive species distribution model (iSDM) development and utilization. This iterative, 10-step framework promotes consistency and transparency in iSDM development, allows for changes in invasive drivers and filters, integrates mechanistic and correlative modeling techniques, balances the avoidance of type 1 and type 2 errors in predictions, encourages the linking of monitoring and management actions, and facilitates incremental improvements in models and management across space, time, and institutional boundaries. These improvements are useful for advancing coordinated invasive species modeling, management and monitoring from local scales to the regional, continental and global scales at which biological invasions occur and harm native ecosystems and economies, as well as for anticipating and responding to biological invasions under continuing global change.

  6. Micro-spatial distribution of two sibling periwinkle species across the intertidal indicates hybrdization.

    Science.gov (United States)

    Granovitch, Andrei I; Maximovich, Alexei N; Avanesyan, Alina V; Starunova, Zinaida I; Mikhailova, Natalia A

    2013-09-01

    Populations of periwinkles Littorina saxatilis (Olivi 1792) and L. arcana Hannaford Ellis, 1978 are well suited for microevolutionary studies, being at the same time closely related and intraspecifically diverse. The divergence between these two sibling species, sympatric over large parts of their distribution areas, is small, the only morphological difference being the pallial gland complex structure in females. Molecular identification is possible with the use of a RAPD nuclear marker (cloned A2.8 DNA fragment) typical for L. arcana. However, in some individuals from sympatric populations molecular and morphological criteria suggest conflicting species affiliation, which may be explained either by hybridization or by shared ancestral polymorphism. We tested the hybridization hypotheses examining the micro-spatial distribution of these two species across the intertidal zone in two distant sites at the Barents Sea. We found that (a) the frequency of putative hybrids in sympatric populations was proportional to the frequency of L. arcana; (b) L. saxatilis bearing A2.8 DNA fragment were almost absent in the lower part of the intertidal zone, where L. arcana was absent too; (c) there was a close positive correlation between the distribution of potential parent molluscs and putative hybrids. Moreover, logistic regression models showed a good agreement between the distribution of putative hybrid frequencies and that of parental species frequencies. All our observations taken together support the hypothesis of hybridization between L. saxatilis and L. arcana. Elucidating the mechanisms that support the species status of these sympatric populations is necessary.

  7. Species distribution models for a migratory bird based on citizen science and satellite tracking data

    Science.gov (United States)

    Coxen, Christopher L.; Frey, Jennifer K.; Carleton, Scott A.; Collins, Daniel P.

    2017-01-01

    Species distribution models can provide critical baseline distribution information for the conservation of poorly understood species. Here, we compared the performance of band-tailed pigeon (Patagioenas fasciata) species distribution models created using Maxent and derived from two separate presence-only occurrence data sources in New Mexico: 1) satellite tracked birds and 2) observations reported in eBird basic data set. Both models had good accuracy (test AUC > 0.8 and True Skill Statistic > 0.4), and high overlap between suitability scores (I statistic 0.786) and suitable habitat patches (relative rank 0.639). Our results suggest that, at the state-wide level, eBird occurrence data can effectively model similar species distributions as satellite tracking data. Climate change models for the band-tailed pigeon predict a 35% loss in area of suitable climate by 2070 if CO2 emissions drop to 1990 levels by 2100, and a 45% loss by 2070 if we continue current CO2 emission levels through the end of the century. These numbers may be conservative given the predicted increase in drought, wildfire, and forest pest impacts to the coniferous forests the species inhabits in New Mexico. The northern portion of the species’ range in New Mexico is predicted to be the most viable through time.

  8. Distribution of Anisakis species larvae from fishes of the Japanese waters.

    Science.gov (United States)

    Quiazon, Karl Marx A; Yoshinaga, Tomoyoshi; Ogawa, Kazuo

    2011-06-01

    Human anisakiasis is caused by the consumption of raw, marinated or undercooked fish and squid infected with nematodes of the genus Anisakis Dujardin, 1845. In view of food safety, this study was carried out to examine the distribution of Anisakis species in marine fishes within Japanese waters. Seven fish species from six localities were collected and examined for Anisakis infection. Morphological and molecular (ITS region and mtDNA cox2 gene) characterization revealed the presence of two, among the three sibling species of Anisakis simplex, viz. A. simplex sensu stricto (s.s.) and A. pegreffii. Distribution data were collated with the results from the previous researches to better understand Anisakis distribution in Japanese waters. Distributions of Anisakis species were found to be locality-specific rather than host-specific, particularly between the two major species, A. simplex s.s. and A. pegreffii. Anisakis simplex s.s. is mainly found in fishes from northern Japan to Pacific sides, whereas A. pegreffii is in fishes from the Sea of Japan to East China Sea sides. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  9. Dispersal leads to spatial autocorrelation in species distributions: A simulation model

    Science.gov (United States)

    Bahn, V.; Krohn, W.B.; O'Connor, R.J.

    2008-01-01

    Compared to population growth regulated by local conditions, dispersal has been underappreciated as a central process shaping the spatial distribution of populations. This paper asks: (a) which conditions increase the importance of dispersers relative to local recruits in determining population sizes? and (b) how does dispersal influence the spatial distribution patterns of abundances among connected populations? We approached these questions with a simulation model of populations on a coupled lattice with cells of continuously varying habitat quality expressed as carrying capacities. Each cell contained a population with the basic dynamics of density-regulated growth, and was connected to other populations by immigration and emigration. The degree to which dispersal influenced the distribution of population sizes depended most strongly on the absolute amount of dispersal, and then on the potential population growth rate. Dispersal decaying in intensity with distance left close neighbours more alike in population size than distant populations, leading to an increase in spatial autocorrelation. The spatial distribution of species with low potential growth rates is more dependent on dispersal than that of species with high growth rates; therefore, distribution modelling for species with low growth rates requires particular attention to autocorrelation, and conservation management of these species requires attention to factors curtailing dispersal, such as fragmentation and dispersal barriers. ?? 2007 Elsevier B.V. All rights reserved.

  10. LogCauchy, log-sech and lognormal distributions of species abundances in forest communities

    Science.gov (United States)

    Yin, Z.-Y.; Peng, S.-L.; Ren, H.; Guo, Q.; Chen, Z.-H.

    2005-01-01

    Species-abundance (SA) pattern is one of the most fundamental aspects of biological community structure, providing important information regarding species richness, species-area relation and succession. To better describe the SA distribution (SAD) in a community, based on the widely used lognormal (LN) distribution model with exp(-x2) roll-off on Preston's octave scale, this study proposed two additional models, logCauchy (LC) and log-sech (LS), respectively with roll-offs of simple x-2 and e-x. The estimation of the theoretical total number of species in the whole community, S*, including very rare species not yet collected in sample, was derived from the left-truncation of each distribution. We fitted these three models by Levenberg-Marquardt nonlinear regression and measured the model fit to the data using coefficient of determination of regression, parameters' t-test and distribution's Kolmogorov-Smirnov (KS) test. Examining the SA data from six forest communities (five in lower subtropics and one in tropics), we found that: (1) on a log scale, all three models that are bell-shaped and left-truncated statistically adequately fitted the observed SADs, and the LC and LS did better than the LN; (2) from each model and for each community the S* values estimated by the integral and summation methods were almost equal, allowing us to estimate S* using a simple integral formula and to estimate its asymptotic confidence internals by regression of a transformed model containing it; (3) following the order of LC, LS, and LN, the fitted distributions became lower in the peak, less concave in the side, and shorter in the tail, and overall the LC tended to overestimate, the LN tended to underestimate, while the LS was intermediate but slightly tended to underestimate, the observed SADs (particularly the number of common species in the right tail); (4) the six communities had some similar structural properties such as following similar distribution models, having a common

  11. Observations of the distributions of five fish species in a small Appalachian stream

    Science.gov (United States)

    Larson, Gary L.; Hoffman, Robert L.; Moore, S.E.

    2002-01-01

    The notion has been growing that resident stream fishes exhibit a greater capacity for movement than was previously thought. In this study, we recorded the distributions of four resident fish species (longnose dace Rhinichthys cataractae, blacknose dace R. atratulus, mottled sculpin Cottus bairdi, and rainbow trout Oncorhynchus mykiss) and one nonresident species (central stoneroller Campostoma anomalum) in Rock Creek, a small tributary of Cosby Creek in Great Smoky Mountains National Park, over the period 1979a??1995. During this study, 1,998 individuals of resident species were collected from stream sections considered to be within a common area of distribution for each species. Forty-five individuals of resident and nonresident species were captured upstream of these areas, and eight of these fish were considered to be larger than individuals considered typical for each species. Small mammal dispersal theory concepts were used to classify and describe fish movements outside of common areas of distribution. These movements were identified as important in maintaining population connectivity within stream drainages, contributing to reducing the potential for local extinctions of populations and to the recolonization of unoccupied habitats. This study highlights the need for continued study of fish movements in stream drainages and for development of appropriate resource management strategies based partly on the spatial dynamics of fish populations and communities.

  12. Species Distribution Modelling: Contrasting presence-only models with plot abundance data.

    Science.gov (United States)

    Gomes, Vitor H F; IJff, Stéphanie D; Raes, Niels; Amaral, Iêda Leão; Salomão, Rafael P; de Souza Coelho, Luiz; de Almeida Matos, Francisca Dionízia; Castilho, Carolina V; de Andrade Lima Filho, Diogenes; López, Dairon Cárdenas; Guevara, Juan Ernesto; Magnusson, William E; Phillips, Oliver L; Wittmann, Florian; de Jesus Veiga Carim, Marcelo; Martins, Maria Pires; Irume, Mariana Victória; Sabatier, Daniel; Molino, Jean-François; Bánki, Olaf S; da Silva Guimarães, José Renan; Pitman, Nigel C A; Piedade, Maria Teresa Fernandez; Mendoza, Abel Monteagudo; Luize, Bruno Garcia; Venticinque, Eduardo Martins; de Leão Novo, Evlyn Márcia Moraes; Vargas, Percy Núñez; Silva, Thiago Sanna Freire; Manzatto, Angelo Gilberto; Terborgh, John; Reis, Neidiane Farias Costa; Montero, Juan Carlos; Casula, Katia Regina; Marimon, Beatriz S; Marimon, Ben-Hur; Coronado, Euridice N Honorio; Feldpausch, Ted R; Duque, Alvaro; Zartman, Charles Eugene; Arboleda, Nicolás Castaño; Killeen, Timothy J; Mostacedo, Bonifacio; Vasquez, Rodolfo; Schöngart, Jochen; Assis, Rafael L; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Laurance, William F; Camargo, José Luís; Demarchi, Layon O; Laurance, Susan G W; de Sousa Farias, Emanuelle; Nascimento, Henrique Eduardo Mendonça; Revilla, Juan David Cardenas; Quaresma, Adriano; Costa, Flavia R C; Vieira, Ima Célia Guimarães; Cintra, Bruno Barçante Ladvocat; Castellanos, Hernán; Brienen, Roel; Stevenson, Pablo R; Feitosa, Yuri; Duivenvoorden, Joost F; Aymard C, Gerardo A; Mogollón, Hugo F; Targhetta, Natalia; Comiskey, James A; Vicentini, Alberto; Lopes, Aline; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Emilio, Thaise; Alonso, Alfonso; Neill, David; Dallmeier, Francisco; Ferreira, Leandro Valle; Araujo-Murakami, Alejandro; Praia, Daniel; do Amaral, Dário Dantas; Carvalho, Fernanda Antunes; de Souza, Fernanda Coelho; Feeley, Kenneth; Arroyo, Luzmila; Pansonato, Marcelo Petratti; Gribel, Rogerio; Villa, Boris; Licona, Juan Carlos; Fine, Paul V A; Cerón, Carlos; Baraloto, Chris; Jimenez, Eliana M; Stropp, Juliana; Engel, Julien; Silveira, Marcos; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Maas, Paul; Thomas-Caesar, Raquel; Henkel, Terry W; Daly, Doug; Paredes, Marcos Ríos; Baker, Tim R; Fuentes, Alfredo; Peres, Carlos A; Chave, Jerome; Pena, Jose Luis Marcelo; Dexter, Kyle G; Silman, Miles R; Jørgensen, Peter Møller; Pennington, Toby; Di Fiore, Anthony; Valverde, Fernando Cornejo; Phillips, Juan Fernando; Rivas-Torres, Gonzalo; von Hildebrand, Patricio; van Andel, Tinde R; Ruschel, Ademir R; Prieto, Adriana; Rudas, Agustín; Hoffman, Bruce; Vela, César I A; Barbosa, Edelcilio Marques; Zent, Egleé L; Gonzales, George Pepe Gallardo; Doza, Hilda Paulette Dávila; de Andrade Miranda, Ires Paula; Guillaumet, Jean-Louis; Pinto, Linder Felipe Mozombite; de Matos Bonates, Luiz Carlos; Silva, Natalino; Gómez, Ricardo Zárate; Zent, Stanford; Gonzales, Therany; Vos, Vincent A; Malhi, Yadvinder; Oliveira, Alexandre A; Cano, Angela; Albuquerque, Bianca Weiss; Vriesendorp, Corine; Correa, Diego Felipe; Torre, Emilio Vilanova; van der Heijden, Geertje; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Young, Kenneth R; Rocha, Maira; Nascimento, Marcelo Trindade; Medina, Maria Natalia Umaña; Tirado, Milton; Wang, Ophelia; Sierra, Rodrigo; Torres-Lezama, Armando; Mendoza, Casimiro; Ferreira, Cid; Baider, Cláudia; Villarroel, Daniel; Balslev, Henrik; Mesones, Italo; Giraldo, Ligia Estela Urrego; Casas, Luisa Fernanda; Reategui, Manuel Augusto Ahuite; Linares-Palomino, Reynaldo; Zagt, Roderick; Cárdenas, Sasha; Farfan-Rios, William; Sampaio, Adeilza Felipe; Pauletto, Daniela; Sandoval, Elvis H Valderrama; Arevalo, Freddy Ramirez; Huamantupa-Chuquimaco, Isau; Garcia-Cabrera, Karina; Hernandez, Lionel; Gamarra, Luis Valenzuela; Alexiades, Miguel N; Pansini, Susamar; Cuenca, Walter Palacios; Milliken, William; Ricardo, Joana; Lopez-Gonzalez, Gabriela; Pos, Edwin; Ter Steege, Hans

    2018-01-17

    Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider this limitation, especially for large biodiversity assessments projects, when they are automatically generated without subsequent checking. Our pipeline provides a conservative estimate of a species' area of occupancy, within an area slightly larger than its extent of occurrence, compatible to e.g. IUCN red list assessments.

  13. Spatial Distribution of Cryptic Species Diversity in European Freshwater Amphipods (Gammarus fossarum) as Revealed by Pyrosequencing

    Science.gov (United States)

    Westram, Anja Marie; Jokela, Jukka; Baumgartner, Caroline; Keller, Irene

    2011-01-01

    In order to understand and protect ecosystems, local gene pools need to be evaluated with respect to their uniqueness. Cryptic species present a challenge in this context because their presence, if unrecognized, may lead to serious misjudgement of the distribution of evolutionarily distinct genetic entities. In this study, we describe the current geographical distribution of cryptic species of the ecologically important stream amphipod Gammarus fossarum (types A, B and C). We use a novel pyrosequencing assay for molecular species identification and survey 62 populations in Switzerland, plus several populations in Germany and eastern France. In addition, we compile data from previous publications (mainly Germany). A clear transition is observed from type A in the east (Danube and Po drainages) to types B and, more rarely, C in the west (Meuse, Rhone, and four smaller French river systems). Within the Rhine drainage, the cryptic species meet in a contact zone which spans the entire G. fossarum distribution range from north to south. This large-scale geographical sorting indicates that types A and B persisted in separate refugia during Pleistocene glaciations. Within the contact zone, the species rarely co-occur at the same site, suggesting that ecological processes may preclude long-term coexistence. The clear phylogeographical signal observed in this study implies that, in many parts of Europe, only one of the cryptic species is present. PMID:21909373

  14. Spatial distribution of cryptic species diversity in european freshwater amphipods (Gammarus fossarum as revealed by pyrosequencing.

    Directory of Open Access Journals (Sweden)

    Anja Marie Westram

    Full Text Available In order to understand and protect ecosystems, local gene pools need to be evaluated with respect to their uniqueness. Cryptic species present a challenge in this context because their presence, if unrecognized, may lead to serious misjudgement of the distribution of evolutionarily distinct genetic entities. In this study, we describe the current geographical distribution of cryptic species of the ecologically important stream amphipod Gammarus fossarum (types A, B and C. We use a novel pyrosequencing assay for molecular species identification and survey 62 populations in Switzerland, plus several populations in Germany and eastern France. In addition, we compile data from previous publications (mainly Germany. A clear transition is observed from type A in the east (Danube and Po drainages to types B and, more rarely, C in the west (Meuse, Rhone, and four smaller French river systems. Within the Rhine drainage, the cryptic species meet in a contact zone which spans the entire G. fossarum distribution range from north to south. This large-scale geographical sorting indicates that types A and B persisted in separate refugia during Pleistocene glaciations. Within the contact zone, the species rarely co-occur at the same site, suggesting that ecological processes may preclude long-term coexistence. The clear phylogeographical signal observed in this study implies that, in many parts of Europe, only one of the cryptic species is present.

  15. Distribution of six little known plant species from Arunachal Pradesh, India

    Directory of Open Access Journals (Sweden)

    S.S. Dash

    2011-09-01

    Full Text Available The present paper deals with the distribution status of six plant species from Arunachal Pradesh which were earlier only known from the type locality. Dalbergia thomsonii Benth., Larsenianthus assamensis (S. Dey, Mood & S. Choudhury and Plectocomia himalayana Griff. are reported for the first time from the state while Begonia silhetensis (A. DC. C.B. Clarke, Larsenianthus arunachalensis (M. Sabu, Sanoj & T. Rajesh Kumar and Tricarpelema glanduliferum (J. Joseph & R.S. Rao show extended distribution.

  16. Marine species distribution shifts on the U.S. Northeast Continental Shelf under continued ocean warming

    Science.gov (United States)

    Kleisner, Kristin M.; Fogarty, Michael J.; McGee, Sally; Hare, Jonathan A.; Moret, Skye; Perretti, Charles T.; Saba, Vincent S.

    2017-04-01

    The U.S. Northeast Continental Shelf marine ecosystem has warmed much faster than the global ocean and it is expected that this enhanced warming will continue through this century. Complex bathymetry and ocean circulation in this region have contributed to biases in global climate model simulations of the Shelf waters. Increasing the resolution of these models results in reductions in the bias of future climate change projections and indicates greater warming than suggested by coarse resolution climate projections. Here, we used a high-resolution global climate model and historical observations of species distributions from a trawl survey to examine changes in the future distribution of suitable thermal habitat for various demersal and pelagic species on the Shelf. Along the southern portion of the shelf (Mid-Atlantic Bight and Georges Bank), a projected 4.1 °C (surface) to 5.0 °C (bottom) warming of ocean temperature from current conditions results in a northward shift of the thermal habitat for the majority of species. While some southern species like butterfish and black sea bass are projected to have moderate losses in suitable thermal habitat, there are potentially significant increases for many species including summer flounder, striped bass, and Atlantic croaker. In the north, in the Gulf of Maine, a projected 3.7 °C (surface) to 3.9 °C (bottom) warming from current conditions results in substantial reductions in suitable thermal habitat such that species currently inhabiting this region may not remain in these waters under continued warming. We project a loss in suitable thermal habitat for key northern species including Acadian redfish, American plaice, Atlantic cod, haddock, and thorney skate, but potential gains for some species including spiny dogfish and American lobster. We illustrate how changes in suitable thermal habitat of important commercially fished species may impact local fishing communities and potentially impact major fishing ports

  17. Vertical distribution and species coexistence of tree hole mosquitoes in Louisiana.

    Science.gov (United States)

    Schreiber, E T; Meek, C L; Yates, M M

    1988-03-01

    Vertical distribution and species coexistence of mosquitoes inhabiting a deciduous forest in southern Louisiana were determined using 470 ml black jars for larval collections at ground level and 1, 3, 5, 7 and 9 m on selected trees. Specific preferences for discrete microhabitats by Aedes triseriatus, Ae. hendersoni, Ae. vexans and Ae. albopictus were not evident. Niche overlap indices, however, showed little overlap of these species and seemed to indicate that the mosquitoes partitioned the ovipositional/larval sites. Competition between the most abundant species, Ae. triseriatus and Ae. albopictus, was not apparent. The tree hole mosquito community structure appeared to be mediated by the predator, Toxorhynchites rutilus septentrionalis.

  18. Are range-size distributions consistent with species-level heritability?

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Gotelli, Nicholas; Rahbek, Carsten

    2012-01-01

    The concept of species-level heritability is widely contested. Because it is most likely to apply to emergent, species-level traits, one of the central discussions has focused on the potential heritability of geographic range size. However, a central argument against range-size heritability has...... been that it is not compatible with the observed shape of present-day species range-size distributions (SRDs), a claim that has never been tested. To assess this claim, we used forward simulation of range-size evolution in clades with varying degrees of range-size heritability, and compared the output...

  19. A new species of Argulus from Kosi Bay, South Africa and distribution records of the genus

    Directory of Open Access Journals (Sweden)

    Annemarie Avenant-Oldewage

    1994-09-01

    Full Text Available A new species of the fish ectoparasite Argulus i.e. A. kosus is described from Kosi Bay in South Africa. This species is characterised by deep antero-lateral depressions of the dorsal carapace which delimit a pronounced frontal region, scales are present on the mouth tube, varying numbers of sclerites are present on the maxillae, no flagella occur on the swimming legs nor any scales on the antennae. The shape of the respiratory areas are also typical for this species. A table of the distribution of the genus in South Africa and a map showing the localities, is also included.

  20. Species diversity and distribution patterns of the ants of Amazonian Ecuador.

    Directory of Open Access Journals (Sweden)

    Kari T Ryder Wilkie

    Full Text Available Ants are among the most diverse, abundant and ecologically significant organisms on earth. Although their species richness appears to be greatest in the New World tropics, global patterns of ant diversity and distribution are not well understood. We comprehensively surveyed ant diversity in a lowland primary rainforest in Western Amazonia, Ecuador using canopy fogging, pitfall traps, baits, hand collecting, mini-Winkler devices and subterranean probes to sample ants. A total of 489 ant species comprising 64 genera in nine subfamilies were identified from samples collected in only 0.16 square kilometers. The most species-rich genera were Camponotus, Pheidole, Pseudomyrmex, Pachycondyla, Brachymyrmex, and Crematogaster. Camponotus and Pseudomyrmex were most diverse in the canopy, while Pheidole was most diverse on the ground. The three most abundant ground-dwelling ant genera were Pheidole, Solenopsis and Pyramica. Crematogaster carinata was the most abundant ant species in the canopy; Wasmannia auropunctata was most abundant on the ground, and the army ant Labidus coecus was the most abundant subterranean species. Ant species composition among strata was significantly different: 80% of species were found in only one stratum, 17% in two strata, and 3% in all three strata. Elevation and the number of logs and twigs available as nest sites were significant predictors of ground-dwelling ant species richness. Canopy species richness was not correlated with any ecological variable measured. Subterranean species richness was negatively correlated with depth in the soil. When ant species were categorized using a functional group matrix based on diet, nest-site preference and foraging ecology, the greatest diversity was found in Omnivorous Canopy Nesters. Our study indicates ant species richness is exceptionally high at Tiputini. We project 647-736 ant species in this global hotspot of biodiversity. Considering the relatively small area surveyed, this

  1. Species diversity and distribution patterns of the ants of Amazonian Ecuador.

    Science.gov (United States)

    Ryder Wilkie, Kari T; Mertl, Amy L; Traniello, James F A

    2010-10-01

    Ants are among the most diverse, abundant and ecologically significant organisms on earth. Although their species richness appears to be greatest in the New World tropics, global patterns of ant diversity and distribution are not well understood. We comprehensively surveyed ant diversity in a lowland primary rainforest in Western Amazonia, Ecuador using canopy fogging, pitfall traps, baits, hand collecting, mini-Winkler devices and subterranean probes to sample ants. A total of 489 ant species comprising 64 genera in nine subfamilies were identified from samples collected in only 0.16 square kilometers. The most species-rich genera were Camponotus, Pheidole, Pseudomyrmex, Pachycondyla, Brachymyrmex, and Crematogaster. Camponotus and Pseudomyrmex were most diverse in the canopy, while Pheidole was most diverse on the ground. The three most abundant ground-dwelling ant genera were Pheidole, Solenopsis and Pyramica. Crematogaster carinata was the most abundant ant species in the canopy; Wasmannia auropunctata was most abundant on the ground, and the army ant Labidus coecus was the most abundant subterranean species. Ant species composition among strata was significantly different: 80% of species were found in only one stratum, 17% in two strata, and 3% in all three strata. Elevation and the number of logs and twigs available as nest sites were significant predictors of ground-dwelling ant species richness. Canopy species richness was not correlated with any ecological variable measured. Subterranean species richness was negatively correlated with depth in the soil. When ant species were categorized using a functional group matrix based on diet, nest-site preference and foraging ecology, the greatest diversity was found in Omnivorous Canopy Nesters. Our study indicates ant species richness is exceptionally high at Tiputini. We project 647-736 ant species in this global hotspot of biodiversity. Considering the relatively small area surveyed, this region of western

  2. Distribution and diversity of fungal species in and adjacent to the Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Balice, R.G.; Jarmie, N.; Rogers, F.J.

    1997-12-01

    Fungi have demonstrated their ability to diversify and specialize to take advantage of new environments (Murphy 1996). These species are essential to the normal functioning of ecosystems and the impacts of human activities may be harmful to fungi. There is a need to inventory fungi throughout the range of their environments. Previously archived information representing 43 sample locations was used to perform a preliminary evaluation of the distributions and diversity of fungal species at the Los Alamos National Laboratory and in adjacent environments. Presence-absence data for 71 species of fungi in five habitats, pinon-juniper, canyon-bottom ponderosa pine, ponderosa pine, canyon-bottom mixed conifer, and mixed conifer were analyzed. The results indicate that even though fungi occur in each of the habitats, fungal species are not distributed evenly among these habitats. The richness of fungal species is greater in the canyon-bottom mixed conifer and mixed conifer habitats than in the pinon-juniper, canyon-bottom ponderosa pine or ponderosa pine habitats. All but three of the fungal species were recorded in either the canyon-bottom mixed conifer or the mixed conifer habitats, and all but seven of the fungal species were found in the mixed conifer habitat.

  3. Hylid frogs from Mount Ayanganna, Guyana: new species, redescriptions, and distributional records

    Directory of Open Access Journals (Sweden)

    Ross D. MacCulloch

    2005-10-01

    Full Text Available A new species of Osteocephalus, one species of Hyla, three species of Hypsiboas and one of Myersiohyla were collected on Mount Ayanganna, a sandstone Guiana Shield tepui. Hyla warreni, Hypsiboas roraima, H. sibleszi, Myersiohyla kanaima and the new Osteocephalus were collected in high-tepui forest at 1500 m elevation, while Hypsiboas lemai, H. roraima and M. kanaima were also collected in lower montane forest at 870 m. Supplementary descriptions of adults of all species of Hyla, Hypsiboas and Myersiohyla based on the newly collected specimens are provided. Tadpoles of M. kanaima are described. The specimens from Ayanganna represent significant distributional records for several species. This is the first record of Osteocephalus as a member of the Guiana Shield high-tepui herpetofauna.

  4. Moving Uphill: Microbial Facilitation at the Leading Edge of Plant Species Distributional Shifts

    Science.gov (United States)

    Suding, K.; Farrer, E.; Spasojevic, M.; Porazinska, D.; Bueno de Mesquita, C.; Schmidt, S. K.

    2016-12-01

    Climate change is expected to influence species distributions and reshuffle patterns of biodiversity. A key challenge to our understanding of these effects is that biotic interactions - new species to compete with, new stressors that increase dependence on facilitation, new prey or predators - will likely affect the ability of species to track climate at the leading edges of their distributional range. While it is well established that soil biota strongly influence plant abundance and diversity, it has been difficult to quantify the key belowground dynamics. This presentation will investigate the influence of one key biotic interaction, between plants and soil microbiota, on the ability of plant species to track climate change and expand their range uphill in a high montane system in the Front Range of Colorado. High-resolution photography from 1972 and 2008 indicate colonization of tundra vegetation in formerly unvegetated areas. Observational work on the distributions patterns of both plants and soil microbiota (bacteria, fungi and nematodes) in a spatially-explicit grid at the upper edge of plant distributions indicate strong, mostly positive, associations between plant species and soil taxa. Abiotic factors, while important, consistently underpredicted the occurrence of plant species and, in nine of the 12 most common tundra plants, co-occurring microbial taxa were important predictors of plant occurrence. Comparison of plant and microbial distributional patterns in 2007 and 2015 indicate the influence of microbial community composition on assembly and beta-diversity of the plant community over time. Plant colonization patterns in this region previously devoid of vegetation will likely influence carbon, nitrogen and phosphorus dynamics, with downstream consequences on nutrient limitation and phytoplankton composition in alpine lakes.

  5. Using geomorphological variables to predict the spatial distribution of plant species in agricultural drainage networks.

    Science.gov (United States)

    Rudi, Gabrielle; Bailly, Jean-Stéphane; Vinatier, Fabrice

    2018-01-01

    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

  6. Why inputs matter: Selection of climatic variables for species distribution modelling in the Himalayan region

    Science.gov (United States)

    Bobrowski, Maria; Schickhoff, Udo

    2017-04-01

    Betula utilis is a major constituent of alpine treeline ecotones in the western and central Himalayan region. The objective of this study is to provide first time analysis of the potential distribution of Betula utilis in the subalpine and alpine belts of the Himalayan region using species distribution modelling. Using Generalized Linear Models (GLM) we aim at examining climatic factors controlling the species distribution under current climate conditions. Furthermore we evaluate the prediction ability of climate data derived from different statistical methods. GLMs were created using least correlated bioclimatic variables derived from two different climate models: 1) interpolated climate data (i.e. Worldclim, Hijmans et al., 2005) and 2) quasi-mechanistical statistical downscaling (i.e. Chelsa; Karger et al., 2016). Model accuracy was evaluated by the ability to predict the potential species distribution range. We found that models based on variables of Chelsa climate data had higher predictive power, whereas models using Worldclim climate data consistently overpredicted the potential suitable habitat for Betula utilis. Although climatic variables of Worldclim are widely used in modelling species distribution, our results suggest to treat them with caution when remote regions like the Himalayan mountains are in focus. Unmindful usage of climatic variables for species distribution models potentially cause misleading projections and may lead to wrong implications and recommendations for nature conservation. References: Hijmans, R.J., Cameron, S.E., Parra, J.L., Jones, P.G. & Jarvis, A. (2005) Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology, 25, 1965-1978. Karger, D.N., Conrad, O., Böhner, J., Kawohl, T., Kreft, H., Soria-Auza, R.W., Zimmermann, N., Linder, H.P. & Kessler, M. (2016) Climatologies at high resolution for the earth land surface areas. arXiv:1607.00217 [physics].

  7. An Objective Approach to Select Climate Scenarios when Projecting Species Distribution under Climate Change

    Science.gov (United States)

    Casajus, Nicolas; Périé, Catherine; Logan, Travis; Lambert, Marie-Claude; de Blois, Sylvie; Berteaux, Dominique

    2016-01-01

    An impressive number of new climate change scenarios have recently become available to assess the ecological impacts of climate change. Among these impacts, shifts in species range analyzed with species distribution models are the most widely studied. Whereas it is widely recognized that the uncertainty in future climatic conditions must be taken into account in impact studies, many assessments of species range shifts still rely on just a few climate change scenarios, often selected arbitrarily. We describe a method to select objectively a subset of climate change scenarios among a large ensemble of available ones. Our k-means clustering approach reduces the number of climate change scenarios needed to project species distributions, while retaining the coverage of uncertainty in future climate conditions. We first show, for three biologically-relevant climatic variables, that a reduced number of six climate change scenarios generates average climatic conditions very close to those obtained from a set of 27 scenarios available before reduction. A case study on potential gains and losses of habitat by three northeastern American tree species shows that potential future species distributions projected from the selected six climate change scenarios are very similar to those obtained from the full set of 27, although with some spatial discrepancies at the edges of species distributions. In contrast, projections based on just a few climate models vary strongly according to the initial choice of climate models. We give clear guidance on how to reduce the number of climate change scenarios while retaining the central tendencies and coverage of uncertainty in future climatic conditions. This should be particularly useful during future climate change impact studies as more than twice as many climate models were reported in the fifth assessment report of IPCC compared to the previous one. PMID:27015274

  8. New highland distribution records of multiple Anopheles species in the Ecuadorian Andes

    Directory of Open Access Journals (Sweden)

    Hunter Fiona F

    2011-08-01

    Full Text Available Abstract Background Several recent climate change reviews have stressed the possibility of some malaria vectors occupying regions of higher altitudes than previously recorded. Indeed, highland malaria has been observed in several African nations, possibly attributable to changes in land use, vector control and local climate. This study attempts to expand the current knowledge of the distribution of common Anopheles species in Ecuador, with particular attention to highland regions (> 500 m of the Andes. Methods Extensive field collections of larvae were undertaken in 2008, 2009 and 2010 throughout all regions of Ecuador (except the lower-altitude Amazonian plain and compared to historical distribution maps reproduced from the 1940s. Larvae were identified using both a morphological key and sequencing of the 800 bp region of the CO1 mitochondrial gene. In addition, spatial statistics (Getis-Ord Hotspot Analysis: Gi* were used to determine high and low-density clusters of each species in Ecuador. Results Distributions have been updated for five species of Anopheles in Ecuador: Anopheles albimanus, Anopheles pseudopunctipennis, Anopheles punctimacula, Anopheles eiseni and Anopheles oswaldoi s.l.. Historical maps indicate that An. pseudopunctipennis used to be widespread in highland Andean valleys, while other species were completely restricted to lowland areas. By comparison, updated maps for the other four collected species show higher maximum elevations and/or more widespread distributions in highland regions than previously recorded. Gi* analysis determined some highland hot spots for An. albimanus, but only cold spots for all other species. Conclusions This study documents the establishment of multiple anopheline species in high altitude regions of Ecuador, often in areas where malaria eradication programs are not focused.

  9. An Objective Approach to Select Climate Scenarios when Projecting Species Distribution under Climate Change.

    Science.gov (United States)

    Casajus, Nicolas; Périé, Catherine; Logan, Travis; Lambert, Marie-Claude; de Blois, Sylvie; Berteaux, Dominique

    2016-01-01

    An impressive number of new climate change scenarios have recently become available to assess the ecological impacts of climate change. Among these impacts, shifts in species range analyzed with species distribution models are the most widely studied. Whereas it is widely recognized that the uncertainty in future climatic conditions must be taken into account in impact studies, many assessments of species range shifts still rely on just a few climate change scenarios, often selected arbitrarily. We describe a method to select objectively a subset of climate change scenarios among a large ensemble of available ones. Our k-means clustering approach reduces the number of climate change scenarios needed to project species distributions, while retaining the coverage of uncertainty in future climate conditions. We first show, for three biologically-relevant climatic variables, that a reduced number of six climate change scenarios generates average climatic conditions very close to those obtained from a set of 27 scenarios available before reduction. A case study on potential gains and losses of habitat by three northeastern American tree species shows that potential future species distributions projected from the selected six climate change scenarios are very similar to those obtained from the full set of 27, although with some spatial discrepancies at the edges of species distributions. In contrast, projections based on just a few climate models vary strongly according to the initial choice of climate models. We give clear guidance on how to reduce the number of climate change scenarios while retaining the central tendencies and coverage of uncertainty in future climatic conditions. This should be particularly useful during future climate change impact studies as more than twice as many climate models were reported in the fifth assessment report of IPCC compared to the previous one.

  10. Addressing potential local adaptation in species distribution models: implications for conservation under climate change

    Science.gov (United States)

    Hällfors, Maria Helena; Liao, Jishan; Dzurisin, Jason D. K.; Grundel, Ralph; Hyvärinen, Marko; Towle, Kevin; Wu, Grace C.; Hellmann, Jessica J.

    2016-01-01

    Species distribution models (SDMs) have been criticized for involving assumptions that ignore or categorize many ecologically relevant factors such as dispersal ability and biotic interactions. Another potential source of model error is the assumption that species are ecologically uniform in their climatic tolerances across their range. Typically, SDMs to treat a species as a single entity, although populations of many species differ due to local adaptation or other genetic differentiation. Not taking local adaptation into account, may lead to incorrect range prediction and therefore misplaced conservation efforts. A constraint is that we often do not know the degree to which populations are locally adapted, however. Lacking experimental evidence, we still can evaluate niche differentiation within a species' range to promote better conservation decisions. We explore possible conservation implications of making type I or type II errors in this context. For each of two species, we construct three separate MaxEnt models, one considering the species as a single population and two of disjunct populations. PCA analyses and response curves indicate different climate characteristics in the current environments of the populations. Model projections into future climates indicate minimal overlap between areas predicted to be climatically suitable by the whole species versus population-based models. We present a workflow for addressing uncertainty surrounding local adaptation in SDM application and illustrate the value of conducting population-based models to compare with whole-species models. These comparisons might result in more cautious management actions when alternative range outcomes are considered.

  11. Incorporating a Process-Based Land Use Variable into Species- Distribution Modelling and an Estimated Probability of Species Occurrence Into a Land Change Model: A Case of Albania

    Science.gov (United States)

    Laze, Kuenda

    2016-08-01

    Modelling of land use may be improved by incorporating the results of species distribution modelling and species distribution modelling may be upgraded if a variable of the process-based variable of forest cover change or accessibility of forest from human settlement is included. This work presents the results of spatially explicit analyses of the changes in forest cover from 2000 to 2007 using the method of Geographically Weighted Regression (GWR) and of the species distribution for protected species of Lynx lynx martinoi, Ursus arctos using Generalized Linear Models (GLMs). The methodological approach is separately searching for a parsimonious model for forest cover change and species distribution for the entire territory of Albania. The findings of this work show that modelling of land change and of species distribution is indeed value-added by showing higher values of model selection of corrected Akaike Information Criterion. These results provide evidences on the effects of process-based variables on species distribution modelling and on the performance of species distribution modelling as well as show an example of the incorporation of estimated probability of species occurrences in a land change modelling.

  12. Comparison of a species distribution model and a process model from a hierarchical perspective to quantify effects of projected climate change on tree species

    Science.gov (United States)

    Jeffrey E. Schneiderman; Hong S. He; Frank R. Thompson; William D. Dijak; Jacob S. Fraser

    2015-01-01

    Tree species distribution and abundance are affected by forces operating across a hierarchy of ecological scales. Process and species distribution models have been developed emphasizing forces at different scales. Understanding model agreement across hierarchical scales provides perspective on prediction uncertainty and ultimately enables policy makers and managers to...

  13. Distributional shifts of species in the North Atlantic: the rule or the exception?

    DEFF Research Database (Denmark)

    Payne, Mark

    This work addresses recent shifts in the distribution of marine pelagic fish in the northern North Atlantic and attempts to set them in the context of climate variability, climate change, population dynamics and migration processes. Shifts in the distribution of North-east Atlantic mackerel...... and discussed here. These examples are then used to illustrate the potential importance of various mechanisms that can control the distribution of these species, such as climate variability and change, and population and migration dynamics. A set of simple analytical approaches is demonstrated that can be used...

  14. Using Environmental DNA to Improve Species Distribution Models for Freshwater Invaders

    Directory of Open Access Journals (Sweden)

    Teja P. Muha

    2017-12-01

    Full Text Available Species Distribution Models (SDMs have been reported as a useful tool for the risk assessment and modeling of the pathways of dispersal of freshwater invasive alien species (IAS. Environmental DNA (eDNA is a novel tool that can help detect IAS at their early stage of introduction and additionally improve the data available for a more efficient management. SDMs rely on presence and absence of the species in the study area to infer the predictors affecting species distributions. Presence is verified once a species is detected, but confirmation of absence can be problematic because this depends both on the detectability of the species and the sampling strategy. eDNA is a technique that presents higher detectability and accuracy in comparison to conventional sampling techniques, and can effectively differentiate between presence or absence of specific species or entire communities by using a barcoding or metabarcoding approach. However, a number of potential bias can be introduced during (i sampling, (ii amplification, (iii sequencing, or (iv through the usage of bioinformatics pipelines. Therefore, it is important to report and conduct the field and laboratory procedures in a consistent way, by (i introducing eDNA independent observations, (ii amplifying and sequencing control samples, (iii achieving quality sequence reads by appropriate clean-up steps, (iv controlling primer amplification preferences, (v introducing PCR-free sequence capturing, (vi estimating primer detection capabilities through controlled experiments and/or (vii post-hoc introduction of “site occupancy-detection models.” With eDNA methodology becoming increasingly routine, its use is strongly recommended to retrieve species distributional data for SDMs.

  15. Climate controls the distribution of a widespread invasive species: Implications for future range expansion

    Science.gov (United States)

    McDowell, W.G.; Benson, A.J.; Byers, J.E.

    2014-01-01

    1. Two dominant drivers of species distributions are climate and habitat, both of which are changing rapidly. Understanding the relative importance of variables that can control distributions is critical, especially for invasive species that may spread rapidly and have strong effects on ecosystems. 2. Here, we examine the relative importance of climate and habitat variables in controlling the distribution of the widespread invasive freshwater clam Corbicula fluminea, and we model its future distribution under a suite of climate scenarios using logistic regression and maximum entropy modelling (MaxEnt). 3. Logistic regression identified climate variables as more important than habitat variables in controlling Corbicula distribution. MaxEnt modelling predicted Corbicula's range expansion westward and northward to occupy half of the contiguous United States. By 2080, Corbicula's potential range will expand 25–32%, with more than half of the continental United States being climatically suitable. 4. Our combination of multiple approaches has revealed the importance of climate over habitat in controlling Corbicula's distribution and validates the climate-only MaxEnt model, which can readily examine the consequences of future climate projections. 5. Given the strong influence of climate variables on Corbicula's distribution, as well as Corbicula's ability to disperse quickly and over long distances, Corbicula is poised to expand into New England and the northern Midwest of the United States. Thus, the direct effects of climate change will probably be compounded by the addition of Corbicula and its own influences on ecosystem function.

  16. Effects of Dispersal-Related Factors on Species Distribution Model Accuracy for Boreal Lake Ecosystems

    Directory of Open Access Journals (Sweden)

    Simon Hallstan

    2013-05-01

    Full Text Available Species distribution modeling is used in applied ecology; for example in predicting the consequences of global change. However, questions still remain about the robustness of model predictions. Here we estimate effects of landscape spatial configuration and organism flight ability—factors related to dispersal—on the accuracy of species distribution models. Distribution models were developed for 129 phytoplankton taxa, 164 littoral invertebrate taxa and 44 profundal invertebrate taxa sampled in 105 Swedish lakes, using six different modeling techniques (generalized linear models (GLM, multivariate adaptive regression splines (MARS, classification tree analysis (CTA, mixture discriminant analysis (MDA, generalized boosting models (GBM and random forests (RF. Model accuracy was not affected by dispersal ability (i.e., invertebrate flight ability, but the accuracy of phytoplankton assemblage predictions and, to a lesser extent, littoral invertebrate assemblages were related to ecosystem size and connectivity. Although no general pattern across species or spatial configuration was evident from our study, we recommend that dispersal and spatial configuration of ecosystems should be considered when developing species distribution models.

  17. Changes in North Sea macrofauna communities and species distribution between 1986 and 2000

    NARCIS (Netherlands)

    Kröncke, I.; Reiss, H.; Eggleton, J.D.; Aldridge, J.; Bergman, M.J.N.; Cochrane, S.; Craeymeersch, J.A.; Degraer, S.; Desroy, N.; Dewarumez, J.-M.; Duineveld, G.C.A.; Essink, K.; Hillewaert, H.; Lavaleye, M.S.S.; Moll, A.; Nehring, S.; Newell, R.; Oug, E.; Pohlmann, T.; Rachor, E.; Robertson, M.; Rumohr, H.; Schratzberger, M.; Smith, R.; Vanden Berghe, E.; van Dalfsen, J.; Van Hoey, G.; Vincx, M.; Willems, W.; Rees, H.L.

    2011-01-01

    The North Sea Benthos Project 2000 was initiated as a follow-up to the 1986 ICES North Sea Benthos Survey with the major aim to identify changes in the macrofauna species distribution and community structure in the North Sea and their likely causes.The results showed that the large-scale spatial

  18. Changes in North Sea macrofauna communities and species distribution between 1986 and 2000

    NARCIS (Netherlands)

    Kroncke, I.; Reiss, H.; Eggleton, J.D.; Craeymeersch, J.A.M.

    2011-01-01

    The North Sea Benthos Project 2000 was initiated as a follow-up to the 1986 ICES North Sea Benthos Survey with the major aim to identify changes in the macrofauna species distribution and community structure in the North Sea and their likely causes. The results showed that the large-scale spatial

  19. Probabilistic accounting of uncertainty in forecasts of species distributions under climate change

    Science.gov (United States)

    Seth J. Wenger; Nicholas A. Som; Daniel C. Dauwalter; Daniel J. Isaak; Helen M. Neville; Charles H. Luce; Jason B. Dunham; Michael K. Young; Kurt D. Fausch; Bruce E. Rieman

    2013-01-01

    Forecasts of species distributions under future climates are inherently uncertain, but there have been few attempts to describe this uncertainty comprehensively in a probabilistic manner. We developed a Monte Carlo approach that accounts for uncertainty within generalized linear regression models (parameter uncertainty and residual error), uncertainty among competing...

  20. Distribution and diversity of Arctic-Alpine species in the Balkans

    DEFF Research Database (Denmark)

    Stevanovic, Vladimir; Vukojicic, Snezana; Sinzar-Sekulic, Jasmina

    2009-01-01

    The distributions of 77 Arctic-Alpine species in the Balkans are mapped and the centers of their richness and diversity presented. Within the Dinaric Alps these are Mts Vranica, Durmitor, and Prokletije; in the Scardo-Pindhic mountains, Šarplanina-Rudoka-Korab form a continuous chain; in the Rhod...

  1. Confirming the species-sensitivity distribution concept for endosulfan using laboratory, mesocosm, and field data

    NARCIS (Netherlands)

    Hose, G.C.; Brink, van den P.J.

    2004-01-01

    In Australia, water-quality trigger values for toxicants are derived using protective concentration values based on species-sensitivity distribution (SSD) curves. SSD curves are generally derived from laboratory data with an emphasis on using local or site-specific data. In this study, Australian

  2. Method for estimating potential tree-grade distributions for northeastern forest species

    Science.gov (United States)

    Daniel A. Yaussy; Daniel A. Yaussy

    1993-01-01

    Generalized logistic regression was used to distribute trees into four potential tree grades for 20 northeastern species groups. The potential tree grade is defined as the tree grade based on the length and amount of clear cuttings and defects only, disregarding minimum grading diameter. The algorithms described use site index and tree diameter as the predictive...

  3. New Data on the Vertical Distribution of Some Species of the Flora in Bulgaria

    Directory of Open Access Journals (Sweden)

    Alexander Tashev

    2013-12-01

    Full Text Available During field studies in different floristic regions of Bulgaria in the period 2006-2013, we found localities of Stellaria alsine, Trifolium heldreichianum, Koeleria nitidula, Sieglingia decumbens, Stipa tirsa, Verbascum formanekii, Pedicularis leucodon, Saxifraga stribrnyi, Inula aschersoniana and Scilla bifolia that expand our knowledge of the vertical distribution of these species in Bulgaria, and hence their ecological niche in the country.

  4. Ditch the niche - is the niche a useful concept in ecology or species distribution modelling?

    NARCIS (Netherlands)

    McInerny, Greg J.; Etienne, Rampal S.

    2012-01-01

    In this first of three papers we examine the use of niche concepts in ecology and especially in species distribution modelling (SDM). This paper deliberately focuses on the lack of clarity found in the term niche. Because its meanings are so diverse, the term niche tends to create confusion and

  5. Notes on Distributional Records and Some Characteristics of Five Carnivore Species (Mammalia: Carnivora) in Turkey

    OpenAIRE

    ÖZKURT, Şakir

    1998-01-01

    In this study, carnivore specimens such as Herpestes ichneumon, Hyaena hyaena, Meles meles, Vulpes vulpes, Lutra lutra from various localities were evaluated based on external and cranial morphology, and then were compared with the published papers. Thus, the present status in Turkey of these species along with distribution records were evaluated.

  6. Species richness and distribution of understorey bryophytes in different forest types in Colombian Amazonia

    NARCIS (Netherlands)

    Benavides, J.C.; Duque, A.J.; Duivenvoorden, J.F.; Cleef, A.M.

    2006-01-01

    The first bryophyte survey results from Colombian Amazonia are presented. Bryophyte species, differentiated into mosses and liverworts, and further into four life-form classes, were sampled in 0.1-ha plots. These plots were distributed over four landscape units in the middle Caquetá area:

  7. Ocean warming, a rapid distributional shift, and the hybridization of a coastal fish species.

    Science.gov (United States)

    Potts, Warren M; Henriques, Romina; Santos, Carmen V; Munnik, Kate; Ansorge, Isabelle; Dufois, Francois; Booth, Anthony J; Kirchner, Carola; Sauer, Warwick H H; Shaw, Paul W

    2014-09-01

    Despite increasing awareness of large-scale climate-driven distribution shifts in the marine environment, no study has linked rapid ocean warming to a shift in distribution and consequent hybridization of a marine fish species. This study describes rapid warming (0.8 °C per decade) in the coastal waters of the Angola-Benguela Frontal Zone over the last three decades and a concomitant shift by a temperature sensitive coastal fish species (Argyrosomus coronus) southward from Angola into Namibia. In this context, rapid shifts in distribution across Economic Exclusive Zones will complicate the management of fishes, particularly when there is a lack of congruence in the fisheries policy between nations. Evidence for recent hybridization between A. coronus and a congener, A. inodorus, indicate that the rapid shift in distribution of A. coronus has placed adults of the two species in contact during their spawning events. Ocean warming may therefore revert established species isolation mechanisms and alter the evolutionary history of fishes. While the consequences of the hybridization on the production of the resource remain unclear, this will most likely introduce additional layers of complexity to their management. © 2014 John Wiley & Sons Ltd.

  8. Species distribution modelling: Contrasting presence-only models with plot abundance data

    DEFF Research Database (Denmark)

    Gomes , Vitor H. F.; Balslev, Henrik; ter Steege, Hans

    2018-01-01

    . Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area...

  9. Comparative demography of two co-occurring Linum species with different distribution patterns.

    Science.gov (United States)

    Münzbergová, Z

    2013-11-01

    Understanding similarities and differences in population dynamics of closely related species is a key prerequisite in attempts to apply knowledge obtained in one species to another species, e.g., for the purpose of predicting future fate of populations of various rare species. It can be expected that species will have similar population dynamics if they are closely related and share similar habitats. Contrasting population sizes and distribution patterns may, however, indicate that the population dynamics will be different. To understand similarities and differences in population dynamics of closely related species, I studied demography of two congeneric endangered species, Linum flavum and L. tenuifolium co-occurring in dry grasslands. Linum flavum occurs with a lower number of large populations, while L. tenuifolium occurs as a large number of small populations. The results showed that L. flavum had higher population growth rates, relied more on survival and growth and its populations were more persistent. In contrast, populations of L. tenuifolium were more prone to extinction and frequent recolonisation was necessary for their survival in the landscape. This was in accordance with observed population sizes of the two species and their frequency in the landscape. The results indicate that despite being closely related and occurring in the same habitat types, the two Linum species have different growth strategies. The strong differences in population dynamics between the two species suggest that similarity in population sizes and frequency of the species in the landscape may be more important when attempting to transfer knowledge between species than is taxonomic relatedness. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

  10. Occurrence and distribution of special status plant species on the Naval Petroleum Reserves in California

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.C.; Cypher, B.L.; Holmstead, G.L.; Hammer, K.L.; Frost, N.

    1994-10-01

    Several special status plant species occur or potentially occur at the Naval Petroleum Reserves in California (NPRC). Special status species are defined as those species that are either federally listed as endangered or threatened, or candidate taxa. Candidate species are classified as Category 1 or Category 2. Category 1 taxa are those species for which there is sufficient evidence to support listing, while Category 2 taxa are those species for which listing may possibly be appropriate, but for which sufficient data are lacking to warrant immediate listing. Determining the presence and distribution of these species on NPRC is necessary so that appropriate conservation or protection measures can be implemented. In the spring of 1988, a survey of Naval Petroleum Reserve No. 1 (NPR-1) was conducted to determine the occurrence of Hoover`s wooly-star (Eriastrum hooveri), Kern Mallow (Eremalche kemensis), San Joaquin wooly-threads (Lembertia congdonii), and California jewelflower (Caulanthus califonicus), all listed by the US Fish and Wildlife Service (FWS) as Category 2 species at that time. Of the four species, only Hoover`s wooly-star was found. It was concluded that Kern mallow and San Joaquin wooly-threads could potentially be found on NPR-1, but habitat for California jewelflower did not occur on NPR-1 and its occurrence was unlikely. As part of an ongoing effort to document the presence or absence of sensitive plant species on NPRC, surveys for species other than Hoover`s wooly-star were conducted in the spring of 1993. Abundant spring rains in 1993 created favorable growing conditions for annual forbs. Surveys in 1993 focused on potential habitat of several endangered and candidate species. The results of those surveys are presented in this report.

  11. Diversity and distribution of freshwater amphipod species in Switzerland (Crustacea: Amphipoda).

    Science.gov (United States)

    Altermatt, Florian; Alther, Roman; Fišer, Cene; Jokela, Jukka; Konec, Marjeta; Küry, Daniel; Mächler, Elvira; Stucki, Pascal; Westram, Anja Marie

    2014-01-01

    Amphipods are key organisms in many freshwater systems and contribute substantially to the diversity and functioning of macroinvertebrate communities. Furthermore, they are commonly used as bioindicators and for ecotoxicological tests. For many areas, however, diversity and distribution of amphipods is inadequately known, which limits their use in ecological and ecotoxicological studies and handicaps conservation initiatives. We studied the diversity and distribution of amphipods in Switzerland (Central Europe), covering four major drainage basins, an altitudinal gradient of>2,500 m, and various habitats (rivers, streams, lakes and groundwater). We provide the first provisional checklist and detailed information on the distribution and diversity of all amphipod species from Switzerland. In total, we found 29 amphipod species. This includes 16 native and 13 non-native species, one of the latter (Orchestia cavimana) reported here for the first time for Switzerland. The diversity is compared to neighboring countries. We specifically discuss species of the genus Niphargus, which are often receiving less attention. We also found evidence of an even higher level of hidden diversity, and the potential occurrence of further cryptic species. This diversity reflects the biogeographic past of Switzerland, and suggests that amphipods are ideally suited to address questions on endemism and adaptive radiations, post-glaciation re-colonization and invasion dynamics as well as biodiversity-ecosystem functioning relationships in aquatic systems.

  12. Species and distribution of inorganic and organic phosphorus in enhanced phosphorus removal aerobic granular sludge.

    Science.gov (United States)

    Huang, Wenli; Huang, Weiwei; Li, Huifang; Lei, Zhongfang; Zhang, Zhenya; Tay, Joo Hwa; Lee, Duu-Jong

    2015-10-01

    The species and distribution of phosphorus (P) in an enhanced biological phosphorus removal (EBPR)-aerobic granular sludge (AGS) were fractionated and further analyzed. Results showed that microbial cells, extracellular polymeric substances (EPS) and mineral precipitates contributed about 73.7%, 17.6% and 5.3-6.4% to the total P (TP) of EBPR-AGS, respectively. Inorganic P (IP) species were orthophosphate, pyrophosphate and polyphosphate among which polyphosphate was the major P species in the AGS, cells and EPS. Monoester and diester phosphates were identified as the organic P (OP) species in the AGS and cells. Hydroxyapatite (Ca5(PO4)3OH) and calcium phosphate (Ca2(PO4)3) were the dominant P minerals accumulated in the core of the granules. Cells along with polyphosphate were mainly in the outer layer of AGS while EPS were distributed in the whole granules. Based on the above results, the distribution of IP and OP species in AGS has been conceived. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Selection bias in species distribution models: An econometric approach on forest trees based on structural modeling

    Science.gov (United States)

    Martin-StPaul, N. K.; Ay, J. S.; Guillemot, J.; Doyen, L.; Leadley, P.

    2014-12-01

    Species distribution models (SDMs) are widely used to study and predict the outcome of global changes on species. In human dominated ecosystems the presence of a given species is the result of both its ecological suitability and human footprint on nature such as land use choices. Land use choices may thus be responsible for a selection bias in the presence/absence data used in SDM calibration. We present a structural modelling approach (i.e. based on structural equation modelling) that accounts for this selection bias. The new structural species distribution model (SSDM) estimates simultaneously land use choices and species responses to bioclimatic variables. A land use equation based on an econometric model of landowner choices was joined to an equation of species response to bioclimatic variables. SSDM allows the residuals of both equations to be dependent, taking into account the possibility of shared omitted variables and measurement errors. We provide a general description of the statistical theory and a set of applications on forest trees over France using databases of climate and forest inventory at different spatial resolution (from 2km to 8km). We also compared the outputs of the SSDM with outputs of a classical SDM (i.e. Biomod ensemble modelling) in terms of bioclimatic response curves and potential distributions under current climate and climate change scenarios. The shapes of the bioclimatic response curves and the modelled species distribution maps differed markedly between SSDM and classical SDMs, with contrasted patterns according to species and spatial resolutions. The magnitude and directions of these differences were dependent on the correlations between the errors from both equations and were highest for higher spatial resolutions. A first conclusion is that the use of classical SDMs can potentially lead to strong miss-estimation of the actual and future probability of presence modelled. Beyond this selection bias, the SSDM we propose represents

  14. [Study on distributed patterns of scoparone and ayapin in Dendrobium species from Yunnan].

    Science.gov (United States)

    Liu, Yan-Yan; Yu, Hong; Yuan, Feng; Zhou, Feng; Chen, Ye-Gao

    2013-11-01

    An HPLC method for determination of scoparone and ayapin was established for investigating the distributed patterns of scoparone and ayapin in 37 species of Dendrobium. The contents of scoparone and ayapin in varied collected samples were determined by the established HPLC method. The pseudo-bulbs sampled were collected according to different growth age of D. thyrsiflorum. The results showed that the contents of scoparone and ayapin were much differently distributed in species of Dendrobium. Only D. thyrsiflorum and D. densfilorum contained both scoparone and ayapin, the content decreased with the growth age. A fewer amount of ayapin was tested in D. loddigesii from Wenshan. The scoparone and ayapin were not determined in the rest species of Dendrobium. The method was concise, sensitive, accurate and reproducible. It could be applied to assay scoparone and ayapin in populations of herbal Dendrobium.

  15. The prevalence and distribution of Fusarium species in Norwegian cereals: a survey

    DEFF Research Database (Denmark)

    Kosiak, B.; Torp, M.; Skjerve, E.

    2003-01-01

    In the period 1994-1996 a post-harvest survey was conducted in wheat, barley and oats to assess the occurrence and geographic distribution of Fusarium species in Norwegian cereals. The number of samples investigated was adjusted proportionally to the production of each cereal species within...... the regions. A total of 695 grain samples were analysed. The amount of Fusarium infection varied with cereal species and region of origin. The most frequently isolated Fusarium spp. from all samples were F. avenaceum, F. poae, F. tricinctum and F. culmorum. Other important toxigenic Fusarium spp. were F....... graminearum, "powdery F. poae ", F. equiseti and F. sporotrichioides . A north-south gradient was valid for F. tricinctum, F. poae and in 1994 for "powdery F. poae ". In 1994 "powdery F. poae " was the most abundant potential producer of HT-2 and T-2 toxins in Norwegian cereals. Distribution of F. graminearum...

  16. BAYESIAN MODELS FOR SPECIES DISTRIBUTION MODELLING WITH ONLY-PRESENCE RECORDS

    Directory of Open Access Journals (Sweden)

    Bartolo de Jesús Villar-Hernández

    2015-08-01

    Full Text Available One of the central issues in ecology is the study of geographical distribution of species of flora and fauna through Species Distribution Models (SDM. Recently, scientific interest has focused on presence-only records. Two recent approaches have been proposed for this problem: a model based on maximum likelihood method (Maxlike and an inhomogeneous poisson process model (IPP. In this paper we discussed two bayesian approaches called MaxBayes and IPPBayes based on Maxlike and IPP model, respectively. To illustrate these proposals, we implemented two study examples: (1 both models were implemented on a simulated dataset, and (2 we modeled the potencial distribution of genus Dalea in the Tehuacan-Cuicatlán biosphere reserve with both models, the results was compared with that of Maxent. The results show that both models, MaxBayes and IPPBayes, are viable alternatives when species distribution are modeled with only-presence records. For simulated dataset, MaxBayes achieved prevalence estimation, even when the number of records was small. In the real dataset example, both models predict similar potential distributions like Maxent does. Â

  17. Distribution of charophyte species in Estonian coastal water (NE Baltic Sea

    Directory of Open Access Journals (Sweden)

    Kaire Torn

    2004-04-01

    Full Text Available Charophytes constitute a group of macrophytes that usually inhabit soft bottoms with shallow water. They occur mostly in fresh-water environments but can also be found in brackish waters. Due to their requirement for clear water they are considered sensitive to eutrophication and therefore often used as an indicator for good water quality. The diverse structure of the Estonian coastline with its numerous sheltered bays and shallow, soft-bottom archipelago areas coupled with low salinity conditions provides an excellent habitat for charophytes. To date, seven species have been described in Estonian coastal waters, NE Baltic Sea. Last systematic investigations on charophyte distribution date back 20-30 years. During the summer of 2001 the locations where charophytes have previously been found were revisited and new sites sampled, to describe the present distribution of quantitative and qualitative parameters of charophyte species. Sampling was performed mainly by SCUBA diving; occurrence, abundance and wet weight biomass were estimated for each location. Six species of charophytes were identified. Compared to previously recorded material, no significant changes in the distribution pattern of charophytes were found. The dependence of charophyte distribution on environmental settings was tested, with depth and substrate quality explaining most of the variability in distribution. Salinity within observed range had minor influence on charophytes.

  18. Effects of climate change, invasive species, and disease on the distribution of native European crayfishes.

    Science.gov (United States)

    Capinha, César; Larson, Eric R; Tricarico, Elena; Olden, Julian D; Gherardi, Francesca

    2013-08-01

    Climate change will require species to adapt to new conditions or follow preferred climates to higher latitudes or elevations, but many dispersal-limited freshwater species may be unable to move due to barriers imposed by watershed boundaries. In addition, invasive nonnative species may expand into new regions under future climate conditions and contribute to the decline of native species. We evaluated future distributions for the threatened European crayfish fauna in response to climate change, watershed boundaries, and the spread of invasive crayfishes, which transmit the crayfish plague, a lethal disease for native European crayfishes. We used climate projections from general circulation models and statistical models based on Mahalanobis distance to predict climate-suitable regions for native and invasive crayfishes in the middle and at the end of the 21st century. We identified these suitable regions as accessible or inaccessible on the basis of major watershed boundaries and present occurrences and evaluated potential future overlap with 3 invasive North American crayfishes. Climate-suitable areas decreased for native crayfishes by 19% to 72%, and the majority of future suitable areas for most of these species were inaccessible relative to native and current distributions. Overlap with invasive crayfish plague-transmitting species was predicted to increase. Some native crayfish species (e.g., noble crayfish [Astacus astacus]) had no future refugia that were unsuitable for the modeled nonnative species. Our results emphasize the importance of preventing additional introductions and spread of invasive crayfishes in Europe to minimize interactions between the multiple stressors of climate change and invasive species, while suggesting candidate regions for the debatable management option of assisted colonization. © 2013 Society for Conservation Biology.

  19. The predictive skill of species distribution models for plankton in a changing climate

    DEFF Research Database (Denmark)

    Brun, Philipp Georg; Kiørboe, Thomas; Licandro, Priscilla

    2016-01-01

    Statistical species distribution models (SDMs) are increasingly used to project spatial relocations of marine taxa under future climate change scenarios. However, tests of their predictive skill in the real-world are rare. Here, we use data from the Continuous Plankton Recorder program, one......, and model skill typically did not outperform a null model assuming distributions to be constant in time. The predicted prevalence increasingly differed from the observed prevalence for predictions with more distance in time from their training dataset. More detailed investigations based on four focal...... species revealed that strong spatial variations in skill exist, with the least skill at the edges of the distributions, where prevalence is lowest. Furthermore, the scores of traditional single-value model performance metrics were contrasting and some implied overoptimistic conclusions about model skill...

  20. Standard test method for distribution coefficients of inorganic species by the batch method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of distribution coefficients of chemical species to quantify uptake onto solid materials by a batch sorption technique. It is a laboratory method primarily intended to assess sorption of dissolved ionic species subject to migration through pores and interstices of site specific geomedia. It may also be applied to other materials such as manufactured adsorption media and construction materials. Application of the results to long-term field behavior is not addressed in this method. Distribution coefficients for radionuclides in selected geomedia are commonly determined for the purpose of assessing potential migratory behavior of contaminants in the subsurface of contaminated sites and waste disposal facilities. This test method is also applicable to studies for parametric studies of the variables and mechanisms which contribute to the measured distribution coefficient. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement a...

  1. Facilitating political decisions using species distribution models to assess restoration measures in heavily modified estuaries.

    Science.gov (United States)

    Heuner, Maike; Weber, Arnd; Schröder, Uwe; Kleinschmit, Birgit; Schröder, Boris

    2016-09-15

    The European Water Framework Directive requires a good ecological potential for heavily modified water bodies. This standard has not been reached for most large estuaries by 2015. Management plans for estuaries fall short in linking implementations between restoration measures and underlying spatial analyses. The distribution of emergent macrophytes - as an indicator of habitat quality - is here used to assess the ecological potential. Emergent macrophytes are capable of settling on gentle tidal flats where hydrodynamic stress is comparatively low. Analyzing their habitats based on spatial data, we set up species distribution models with 'elevation relative to mean high water', 'mean bank slope', and 'length of bottom friction' from shallow water up to the vegetation belt as key predictors representing hydrodynamic stress. Effects of restoration scenarios on habitats were assessed applying these models. Our findings endorse species distribution models as crucial spatial planning tools for implementing restoration measures in modified estuaries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Incorporating spatial autocorrelation into species distribution models alters forecasts of climate-mediated range shifts.

    Science.gov (United States)

    Crase, Beth; Liedloff, Adam; Vesk, Peter A; Fukuda, Yusuke; Wintle, Brendan A

    2014-08-01

    Species distribution models (SDMs) are widely used to forecast changes in the spatial distributions of species and communities in response to climate change. However, spatial autocorrelation (SA) is rarely accounted for in these models, despite its ubiquity in broad-scale ecological data. While spatial autocorrelation in model residuals is known to result in biased parameter estimates and the inflation of type I errors, the influence of unmodeled SA on species' range forecasts is poorly understood. Here we quantify how accounting for SA in SDMs influences the magnitude of range shift forecasts produced by SDMs for multiple climate change scenarios. SDMs were fitted to simulated data with a known autocorrelation structure, and to field observations of three mangrove communities from northern Australia displaying strong spatial autocorrelation. Three modeling approaches were implemented: environment-only models (most frequently applied in species' range forecasts), and two approaches that incorporate SA; autologistic models and residuals autocovariate (RAC) models. Differences in forecasts among modeling approaches and climate scenarios were quantified. While all model predictions at the current time closely matched that of the actual current distribution of the mangrove communities, under the climate change scenarios environment-only models forecast substantially greater range shifts than models incorporating SA. Furthermore, the magnitude of these differences intensified with increasing increments of climate change across the scenarios. When models do not account for SA, forecasts of species' range shifts indicate more extreme impacts of climate change, compared to models that explicitly account for SA. Therefore, where biological or population processes induce substantial autocorrelation in the distribution of organisms, and this is not modeled, model predictions will be inaccurate. These results have global importance for conservation efforts as inaccurate

  3. New records of Lake Baikal leech fauna: species diversity and spatial distribution in Chivyrkuy Gulf.

    Science.gov (United States)

    Kaygorodova, Irina A; Pronin, Nikolay M

    2013-01-01

    The study of several Lake Baikal leech collections offered us the possibility to determine species diversity in the Chivyrkuy Gulf, the biggest one in the lake. As a result, the first information on the Chivyrkuy Hirudinea fauna (Annelida, Clitellata) has been revealed. There are two orders and four families of leeches in the Chivyrkuy Gulf: order Rhynchobdellida (families Glossiphoniidae and Piscicolidae) and order Arhynchobdellida (families Erpobdellidae and Haemopidae). In total, 22 leech species and 2 subspecies belonging to 11 genera were identified. Of these, 4 taxa belong to the family Glossiphoniidae (G. concolor, A. hyalina, A. heteroclita f. papillosa, and A. heteroclita f. striata) recorded in Baikal for the first time. Representatives of 8 unidentified species (Glossophinia sp., Baicaloclepsis sp., Baicalobdella sp., Piscicola sp. 1, Piscicola sp. 2, Erpobdella sp. 1, Erpobdella sp. 2, and Erpobdella sp. 3) have been also recorded. The checklist gives a contemporary overview of the species composition of leech parasites, their hosts, and distribution within the Chivyrkuy Gulf. The analysis of spatial distribution has shown that the leech species diversity is correlated with the biological productivity of the bay. The most diverse community of leech species is detected in the eutrophic zone of the lake.

  4. Distribution and escape of the major neutral species from Titan's atmosphere

    Science.gov (United States)

    Tenishev, Valeriy; Tucker, Orenthal; Borovikov, Dmitry; Combi, Michael R.

    2016-10-01

    Titan possesses the most significant atmosphere among all satellites in the Solar system, and is an important source of material for the Saturn's magnetosphere. Understanding of the neutral species distribution and escape is important for further understanding of the Titan's atmosphere evolution and loss.The first in situ observations of the Titan's atmosphere were performed by Voyager and continued by Cassini, which measured the atmospheric composition, velocity and temperature, as well as the energy spectra of neutral species, ions and electrons. Analysis and interpretation of the acquired data involves coupled modeling of the Saturn magnetosphere and Titan's atmosphere.Having that in mind we have undertaken numerical modeling of the major neutral species (N2 and CH4) in Titan's upper atmosphere to investigate the effect of the solar EUV and magnetospheric ion energy deposition on the neutral species atmospheric distribution and escape. This modeling combines MHD simulation of the Saturn's magnetosphere plasma interacting with Titan's atmosphere, fluid type simulation of the neutral species in Titan's lower atmosphere, and kinetic modeling of the upper atmosphere and exosphere. Here we present estimations of the neutral species escape rate, and discuss the effect of the magnetospheric ion energy deposition on the atmospheric escape concluded from the results of our modeling.This work was supported by NASA Outer Planet Research grant NNX13AL04G.

  5. Distribution of the Chuckwalla, Western Burrowing Owl, and Six Bat Species on the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Cathy A. Willis

    1997-05-01

    Field Surveys were conducted in 1996 to determine the current distribution of several animal species of concern on the Nevada Test Site (NTS). They included the chuckwall (Sauromalus obesus), western burrowing owl (Speotyto cunicularia), and six species of bats. Nineteen chuckwallas and 118 scat locations were found during the chuckwalla field study. Eighteen western burrowing owls were found at 12 sighting locations during the 1996 field study. Of the eleven bat species of concern which might occur on the NTS, five, and possibly six, were captured during this survey. The U.S. Department of Energy, Nevada Operations Office, takes certain management actions to protect and conserve the chuckwalla, western burrowing owl, and bats on the NTS. These actions are described and include: (1) conducting surveys at sites of proposed land-disturbing activities (2) altering projects whenever possible to avoid or minimize impacts to these species (3) maintaining a geospatial database of known habitat for species of concern (4) sharing sighting and trap location data gathered on the NTS with other local land and resource managers, and (5) conducting periodic field surveys to monitor these species distribution and relative abundance on the NTS.

  6. A framework for using niche models to estimate impacts of climate change on species distributions.

    Science.gov (United States)

    Anderson, Robert P

    2013-09-01

    Predicting species geographic distributions in the future is an important yet exceptionally challenging endeavor. Overall, it requires a two-step process: (1) a niche model characterizing suitability, applied to projections of future conditions and linked to (2) a dispersal/demographic simulation estimating the species' future occupied distribution. Despite limitations, for the vast majority of species, correlative approaches are the most feasible avenue for building niche models. In addition to myriad technical issues regarding model building, researchers should follow critical principles for selecting predictor variables and occurrence data, demonstrating effective performance in prediction across space, and extrapolating into nonanalog conditions. Many of these principles relate directly to the niche space, dispersal/demographic noise, biotic noise, and human noise assumptions defined here. Issues requiring progress include modeling interactions between abiotic variables, integrating biotic variables, considering genetic heterogeneity, and quantifying uncertainty. Once built, the niche model identifying currently suitable conditions must be processed to approximate the areas that the species occupies. That estimate serves as a seed for the simulation of persistence, dispersal, and establishment in future suitable areas. The dispersal/demographic simulation also requires data regarding the species' dispersal ability and demography, scenarios for future land use, and the capability of considering multiple interacting species simultaneously. © 2013 New York Academy of Sciences.

  7. Inferential monitoring of global change impact on biodiversity through remote sensing and species distribution modeling

    Science.gov (United States)

    Sangermano, Florencia

    2009-12-01

    The world is suffering from rapid changes in both climate and land cover which are the main factors affecting global biodiversity. These changes may affect ecosystems by altering species distributions, population sizes, and community compositions, which emphasizes the need for a rapid assessment of biodiversity status for conservation and management purposes. Current approaches on monitoring biodiversity rely mainly on long term observations of predetermined sites, which require large amounts of time, money and personnel to be executed. In order to overcome problems associated with current field monitoring methods, the main objective of this dissertation is the development of framework for inferential monitoring of the impact of global change on biodiversity based on remotely sensed data coupled with species distribution modeling techniques. Several research pieces were performed independently in order to fulfill this goal. First, species distribution modeling was used to identify the ranges of 6362 birds, mammals and amphibians in South America. Chapter 1 compares the power of different presence-only species distribution methods for modeling distributions of species with different response curves to environmental gradients and sample sizes. It was found that there is large variability in the power of the methods for modeling habitat suitability and species ranges, showing the importance of performing, when possible, a preliminary gradient analysis of the species distribution before selecting the method to be used. Chapter 2 presents a new methodology for the redefinition of species range polygons. Using a method capable of establishing the uncertainty in the definition of existing range polygons, the automated procedure identifies the relative importance of bioclimatic variables for the species, predicts their ranges and generates a quality assessment report to explore prediction errors. Analysis using independent validation data shows the power of this

  8. Photosynthetic Light Responses May Explain Vertical Distribution of Hymenophyllaceae Species in a Temperate Rainforest of Southern Chile

    National Research Council Canada - National Science Library

    Parra, María José; Acuña, Karina I; Sierra-Almeida, Angela; Sanfuentes, Camila; Saldaña, Alfredo; Corcuera, Luis J; Bravo, León A

    2015-01-01

    ...; other species occupy the whole host height (≥ 10 m; max PPFD > 1000 μmol photons m(-2) s(-1)). Our aim was to study the photosynthetic light responses of two Hymenophyllaceae species in relation to their contrasting distribution...

  9. Spatial autocorrelation in predictors reduces the impact of positional uncertainty in occurrence data on species distribution modelling

    NARCIS (Netherlands)

    Naimi, B.; Skidmore, A.K.; Groen, T.A.; Hamm, N.A.S.

    2011-01-01

    Aim To investigate the impact of positional uncertainty in species occurrences on the predictions of seven commonly used species distribution models (SDMs), and explore its interaction with spatial autocorrelation in predictors. Methods A series of artificial datasets covering 155 scenarios

  10. Interactions Among Spatial Scales Constrain Species Distributions in Fragmented Urban Landscapes

    Directory of Open Access Journals (Sweden)

    Will R. Turner

    2006-12-01

    Full Text Available Understanding species' responses to habitat loss is a major challenge for ecologists and conservation biologists, who need quantitative, yet practical, frameworks to design landscapes better able to sustain native species. I here develop one such framework by synthesizing two ecological paradigms: scale-dependence and constraint-like interactions in biological phenomena. I develop a model and apply it to birds around Tucson, USA, investigating the manner in which spatial scales interact to constrain species distributions in fragmented urban landscapes. Species' responses vary in interesting ways. Surprisingly, most show situations in which habitat at one spatial scale constrains the influence of habitat at another scale. I discuss the implications of this work for conservation in human-dominated landscapes, and the need to recognize constraint-like interactions among processes and spatial scales in ecology.

  11. Cortinarius subgenus Callistei in North America and Europe-type studies, diversity, and distribution of species.

    Science.gov (United States)

    Niskanen, Tuula; Liimatainen, Kare; Kytövuori, Ilkka; Lindström, Håkan; Dentinger, Bryn T M; Ammirati, Joseph F

    2016-09-01

    Five species of Cortinarius subgenus Callistei, are recognized in Europe and North America. Cortinarius callisteus, C. infucatus, and C. neocallisteus sp. nov. have a broad distribution, extending from western North America to Europe. Cortinarius tofaceus is known from eastern North America and Europe, while C. callistei sp. is known only from one locality in Sweden. All five species are primarily associated with coniferous trees. Previously the species were included either in subgenus Leprocybe or subgenus Cortinarius, but recently they have been separated into subgenus Callistei based on molecular data. Type specimens of the names associated with this subgenus were studied and a neotype proposed for C. tofaceus and an epitype for C. infucatus Barcodes for the species are deposited in RefSeq and UNITE. © 2016 by The Mycological Society of America.

  12. Predicting climate change effects on wetland ecosystem services using species distribution modeling and plant functional traits.

    Science.gov (United States)

    Moor, Helen; Hylander, Kristoffer; Norberg, Jon

    2015-01-01

    Wetlands provide multiple ecosystem services, the sustainable use of which requires knowledge of the underlying ecological mechanisms. Functional traits, particularly the community-weighted mean trait (CWMT), provide a strong link between species communities and ecosystem functioning. We here combine species distribution modeling and plant functional traits to estimate the direction of change of ecosystem processes under climate change. We model changes in CWMT values for traits relevant to three key services, focusing on the regional species pool in the Norrström area (central Sweden) and three main wetland types. Our method predicts proportional shifts toward faster growing, more productive and taller species, which tend to increase CWMT values of specific leaf area and canopy height, whereas changes in root depth vary. The predicted changes in CWMT values suggest a potential increase in flood attenuation services, a potential increase in short (but not long)-term nutrient retention, and ambiguous outcomes for carbon sequestration.

  13. Species distributions and climate change:current patterns and future scenarios for biodiversity

    DEFF Research Database (Denmark)

    Hof, Christian

    extinction, one might assume that most species may also be able to successfully cope with contemporary climate change. However, current ecosystems are heavily modified by humans. Among other factors, habitat destruction and fragmentation caused by anthropogenic land-use changes negatively affect species...... orders. The ability to successfully track climatic changes depends on dispersal, which is in turn influenced by ecological adaptations, such as the affiliation with a certain habitat type. A common hypothesis is that species adapted to less persistent habitats have evolved stronger dispersal abilities....... Two studies of my thesis provide evidence for this hypothesis: (1) geographical distributions of dragonflies adapted to less persistent habitats show higher degrees of equilibrium with climatic conditions; (2) spatial patterns of European freshwater species richness and turnover differ strongly among...

  14. Morphometry and Distribution of Senecio Nemorensis agg. Species (Asteraceae in Poland

    Directory of Open Access Journals (Sweden)

    Rola Kaja

    2014-07-01

    Full Text Available A morphometric analysis based on 316 herbarium specimens of Senecio nemorensis agg. indicated the occurrence of the following four species in Poland: S. germanicus Wallr., S. hercynicus Herborg, S. ovatus (G. Gaertn. et al. Willd. and S. ucranicus Hodálová. Principal component analysis (PCA, analysis of variance (ANOVA/Kruskal-Wallis test and canonical discriminant analysis (CDA were applied. Quantitative characters such as supplementary bract length, leaf base width, ligule length and the supplementary/involucral bract length ratio clearly discriminated taxa within S. nemorensis agg. Included is a distribution map of the investigated species based on the examined material, with particular emphasis on the course of the northeastern boundary of S. hercynicus and the northwestern boundary of S. ucranicus. Also given is a determination key for species within S. nemorensis agg. in Poland, together with morphological descriptions of particular species

  15. Trichoderma biodiversity in China: evidence for a North to South distribution of species in East Asia.

    Science.gov (United States)

    Zhang, Chu-long; Druzhinina, Irina S; Kubicek, Christian P; Xu, Tong

    2005-10-15

    Towards assessing the biodiversity and biogeography of Trichoderma, we have analyzed the occurrence of Trichoderma species in soil and litter from four areas in China: North (Hebei province), South-East (Zhejiang province), West (Himalayan, Tibet) and South-West (Yunnan province). One hundred and thirty five isolates were grouped according to tentative morphological identification. A representative 64 isolates were verified at the species level by the oligonucleotide barcode program TrichO Key v.1.0 and the custom BLAST server TrichoBLAST, using sequences of the ITS1 and 2 region of the rRNA cluster and from the longest intron of the tef1 (translation elongation factor 1-alpha) gene. Eleven known species (Trichoderma asperellum, T. koningii, T. atroviride, T. viride, T. velutinum, T. cerinum, T. virens, T. harzianum, T. sinensis, T. citrinoviride, T. longibrachiatum) and two putative new species (T. sp. C1, and T. sp. C2), distinguished from known species both by morphological characters and phylogenetic analysis, were identified. A significant difference in the occurrence of these species was found between the North (Hebei) and South-West (Yunnan) areas, which correlates with previously reported species distributions in Siberia and South-East Asia, respectively. As in previous studies, T. harzianum accounted for almost half of the biodiversity; although, in this study, it was exclusively found in the North, and was predominantly represented by an ITS1 and 2 haplotype, which has so far been rarely found elsewhere. This study therefore reveals a North-South gradient in species distribution in East Asia, and identifies Northern China as a potential center of origin of a unique haplotype of T. harzianum.

  16. Effects of pesticides on soil invertebrates in laboratory studies: A review and analysis using species sensitivity distributions

    NARCIS (Netherlands)

    Frampton, G.K.; Jänsch, S.; Scott-Fordsmand, J.J.; Römbke, J.; Brink, van den P.J.

    2006-01-01

    Species sensitivity distributions (SSD) and 5% hazardous concentrations (HC5) are distribution-based approaches for assessing environmental risks of pollutants. These methods have potential for application in pesticide risk assessments, but their applicability for assessing pesticide risks to soil

  17. Diversity distribution patterns of Chinese endemic seed plant species and their implications for conservation planning.

    Science.gov (United States)

    Huang, Jihong; Huang, Jianhua; Lu, Xinghui; Ma, Keping

    2016-09-23

    Endemism is an important concept in biogeography and biodiversity conservation. China is one of the richest countries in biodiversity, with very high levels of plant endemism. In this study, we analysed the distribution patterns of diversity, the degree of differentiation, and the endemicity of Chinese endemic seed plants using the floristic unit as a basic spatial analysis unit and 11 indices. The analysis was based on distribution data of 24,951 native seed plant species (excluding subspecies and varieties) and 12,980 Chinese endemic seed plant species, which were sourced from both specimen records and published references. The distribution patterns of Chinese endemic flora were generally consistent but disproportionate across China for diversity, degree of differentiation and endemicity. The South Hengduan Mountains Subregion had the highest values for all indices. At the regional level, both the Hengduan Mountains and the Central China regions were highest in diversity and degrees of differentiation. However, both the rate of local endemic to native species and the rate of local to Chinese endemic species were highest in the Taiwan Region and the South Taiwan Region. The Hengduan Mountains Region and the Central China Region are two key conservation priority areas for Chinese endemic seed plants.

  18. Congruence between geographic range distribution and local competitive ability of two Lupinus species.

    Science.gov (United States)

    Milla, Rubén; Escudero, Adrián; Iriondo, José M

    2011-09-01

    In spite of its relevance, we lack rigorous evidence on whether widespread species are superior local competitors compared with coexisting narrowly distributed congeners. We ran a competition experiment between two lupins that coexist at their shared geographic range: Lupinus angustifolius L. (widespread) and L. gredensis Gandoger (narrow endemic). • We set up mixed and monospecific populations of the two species, monitored survival and fecundity until the death of the whole cohorts, and measured variables of putative relevance to the competition process. We used aster modeling to address lifetime individual fitness and generalized linear models to assess the effect of species, type of competition, and competition environment on a suite of competition indices. • Lupinus angustifolius showed higher fitness and exerted a stronger competitive effect on its heterospecific neighbors. This occurred through higher fecundity late in the season rather than through differential survival at earlier stages. • This is the first evidence of lifetime superior competitive potential of a widespread species over a narrow endemic congener. This competitive response might scale up to the geographic distribution range and may partially explain the limited distribution of the narrow endemic. Extension to other carefully selected study cases and more in-depth field experiments may help to assess the generality of this pattern and understand how local processes translate into geographic patterns.

  19. Characteristics and distribution of Listeria spp., including Listeria species newly described since 2009.

    Science.gov (United States)

    Orsi, Renato H; Wiedmann, Martin

    2016-06-01

    The genus Listeria is currently comprised of 17 species, including 9 Listeria species newly described since 2009. Genomic and phenotypic data clearly define a distinct group of six species (Listeria sensu strictu) that share common phenotypic characteristics (e.g., ability to grow at low temperature, flagellar motility); this group includes the pathogen Listeria monocytogenes. The other 11 species (Listeria sensu lato) represent three distinct monophyletic groups, which may warrant recognition as separate genera. These three proposed genera do not contain pathogens, are non-motile (except for Listeria grayi), are able to reduce nitrate (except for Listeria floridensis), and are negative for the Voges-Proskauer test (except for L. grayi). Unlike all other Listeria species, species in the proposed new genus Mesolisteria are not able to grow below 7 °C. While most new Listeria species have only been identified in a few countries, the availability of molecular tools for rapid characterization of putative Listeria isolates will likely lead to future identification of isolates representing these new species from different sources. Identification of Listeria sensu lato isolates has not only allowed for a better understanding of the evolution of Listeria and virulence characteristics in Listeria but also has practical implications as detection of Listeria species is often used by the food industry as a marker to detect conditions that allow for presence, growth, and persistence of L. monocytogenes. This review will provide a comprehensive critical summary of our current understanding of the characteristics and distribution of the new Listeria species with a focus on Listeria sensu lato.

  20. Species composition and bathymetric distribution of gorgonians (Anthozoa: Octocorallia on the Southern Mexican Pacific coast

    Directory of Open Access Journals (Sweden)

    Rosalinda Abeytia

    2013-09-01

    Full Text Available Gorgonians are important components of coastal ecosystems, as they provide niches, natural compounds with medical applications and are used as bioindicators. Species composition and assemblage structure of gorgonians (Anthozoa: Octocorallia were studied along a bathymetric profile in the Southern Mexican Pacific coast. Species composition was based on specimens collected within a depth range of 0-70m in 15 sites. The relative abundance of species was determined in six sites at four depths (5, 10, 20 and 25m using three 10m2 transects at each depth level. Twenty-seven species of gorgonians belonging to six genera and three families were registered. The species composition varied with depth: 11 species were distributed between 0-25m depth, while 17 species were found between 40-70m depth interval. The shallow zone is characterized by a relatively large abundance of gorgonians, dominated by colonies of Leptogorgia cuspidata and L. ena. In contrast, the deepest zone was characterized by relatively low abundance of gorgonians, dominated by L. alba, the only species observed in both depth intervals. The similarity analysis showed differences in the composition and abundance of species by depth and site, suggesting that the main factor in determining the assemblage structure is depth. Results of this study suggest that the highest richness of gorgonian species in the study area may be located at depths of 40-70m, whereas the highest abundances are found between 5 and 10m depth. This study represents a contribution to the poorly known eastern Pacific gorgonian biota.

  1. Species composition and bathymetric distribution of gorgonians (Anthozoa: Octocorallia) on the Southern Mexican Pacific coast.

    Science.gov (United States)

    Abeytia, Rosalinda; Guzmán, Hector M; Breedy, Odalisca

    2013-09-01

    Gorgonians are important components of coastal ecosystems, as they provide niches, natural compounds with medical applications and are used as bioindicators. Species composition and assemblage structure of gorgonians (Anthozoa: Octocorallia) were studied along a bathymetric profile in the Southern Mexican Pacific coast. Species composition was based on specimens collected within a depth range of 0-70 m in 15 sites. The relative abundance of species was determined in six sites at four depths (5, 10, 20 and 25 m) using three 10 m2 transects at each depth level. Twenty-seven species of gorgonians belonging to six genera and three families were registered. The species composition varied with depth: 11 species were distributed between 0-25m depth, while 17 species were found between 40-70 m depth interval. The shallow zone is characterized by a relatively large abundance of gorgonians, dominated by colonies of Leptogorgia cuspidata and L. ena. In contrast, the deepest zone was characterized by relatively low abundance of gorgonians, dominated by L. alba, the only species observed in both depth intervals. The similarity analysis showed differences in the composition and abundance of species by depth and site, suggesting that the main factor in determining the assemblage structure is depth. Results of this study suggest that the highest richness of gorgonian species in the study area may be located at depths of 40-70 m, whereas the highest abundances are found between 5 and 10 m depth. This study represents a contribution to the poorly known eastern Pacific gorgonian biota.

  2. Using bioassays and species sensitivity distributions to assess herbicide toxicity towards benthic diatoms.

    Directory of Open Access Journals (Sweden)

    Floriane Larras

    Full Text Available Although benthic diatoms are widely used in ecological studies of aquatic systems, there is still a dearth of data concerning species sensitivities towards several contaminants. Within the same community, different species may respond differently depending on their physiological and ecological characteristics. This lack of knowledge makes specific appropriate risk assessment impossible. To find out whether species sensitivity distribution (SSD could be used to estimate the risk of herbicide toxicity for diatoms, we need to know whether their sensitivity depends on their physiological and ecological characteristics. We carried out single-species bioassays on 11 diatom species exposed to 8 herbicides. Dose-responses relationships were used to extrapolate the Effective Concentration 5 (EC(5 and the Effective Concentration 50 (EC(50 for each exposure. These data were used to fit a SSD curve for each herbicide, and to determine the Hazardous concentration 5 (HC(5 and 50 (HC(50. Our results revealed a high level of variability of the sensitivity in the set of species tested. For photosystem-II inhibitor (PSII herbicides, diatoms species displayed a typical grouping of sensitivity levels consistent with their trophic mode and their ecological guild. N-heterotroph and "motile" guild species were more tolerant of PSII inhibitors, while N-autotroph and "low profile" guild species were more sensitive. Comprehensive SSD curves were obtained for 5 herbicides, but not for sulfonylurea herbicides or for dimetachlor, which had toxicity levels that were below the range of concentration tested. The SSD curves provided the following ranking of toxicity: diuron> terbutryn> isoproturon> atrazine> metolachlor. The HC that affected 5% of the species revealed that, even at the usual environmental concentrations of herbicides, diatom assemblages could be affected, especially by isoproturon, terbutryn, and diuron.

  3. Using bioassays and species sensitivity distributions to assess herbicide toxicity towards benthic diatoms.

    Science.gov (United States)

    Larras, Floriane; Bouchez, Agnès; Rimet, Frédéric; Montuelle, Bernard

    2012-01-01

    Although benthic diatoms are widely used in ecological studies of aquatic systems, there is still a dearth of data concerning species sensitivities towards several contaminants. Within the same community, different species may respond differently depending on their physiological and ecological characteristics. This lack of knowledge makes specific appropriate risk assessment impossible. To find out whether species sensitivity distribution (SSD) could be used to estimate the risk of herbicide toxicity for diatoms, we need to know whether their sensitivity depends on their physiological and ecological characteristics. We carried out single-species bioassays on 11 diatom species exposed to 8 herbicides. Dose-responses relationships were used to extrapolate the Effective Concentration 5 (EC(5)) and the Effective Concentration 50 (EC(50)) for each exposure. These data were used to fit a SSD curve for each herbicide, and to determine the Hazardous concentration 5 (HC(5)) and 50 (HC(50)). Our results revealed a high level of variability of the sensitivity in the set of species tested. For photosystem-II inhibitor (PSII) herbicides, diatoms species displayed a typical grouping of sensitivity levels consistent with their trophic mode and their ecological guild. N-heterotroph and "motile" guild species were more tolerant of PSII inhibitors, while N-autotroph and "low profile" guild species were more sensitive. Comprehensive SSD curves were obtained for 5 herbicides, but not for sulfonylurea herbicides or for dimetachlor, which had toxicity levels that were below the range of concentration tested. The SSD curves provided the following ranking of toxicity: diuron> terbutryn> isoproturon> atrazine> metolachlor. The HC that affected 5% of the species revealed that, even at the usual environmental concentrations of herbicides, diatom assemblages could be affected, especially by isoproturon, terbutryn, and diuron.

  4. Current Knowledge of Leishmania Vectors in Mexico: How Geographic Distributions of Species Relate to Transmission Areas

    Science.gov (United States)

    González, Camila; Rebollar-Téllez, Eduardo A.; Ibáñez-Bernal, Sergio; Becker-Fauser, Ingeborg; Martínez-Meyer, Enrique; Peterson, A. Townsend; Sánchez-Cordero, Víctor

    2011-01-01

    Leishmaniases are a group of vector-borne diseases with different clinical manifestations caused by parasites transmitted by sand fly vectors. In Mexico, the sand fly Lutzomyia olmeca olmeca is the only vector proven to transmit the parasite Leishmania mexicana to humans, which causes leishmaniasis. Other vector species with potential medical importance have been obtained, but their geographic distributions and relation to transmission areas have never been assessed. We modeled the ecological niches of nine sand fly species and projected niches to estimate potential distributions by using known occurrences, environmental coverages, and the algorithms GARP and Maxent. All vector species were distributed in areas with known recurrent transmission, except for Lu. diabolica, which appeared to be related only to areas of occasional transmission in northern Mexico. The distribution of Lu. o. olmeca does not overlap with all reported cutaneous leishmaniasis cases, suggesting that Lu. cruciata and Lu. shannoni are likely also involved as primary vectors in those areas. Our study provides useful information of potential risk areas of leishmaniasis transmission in Mexico. PMID:22049037

  5. Species-environment relationships and potential for distribution modelling in coastal waters

    Science.gov (United States)

    Snickars, M.; Gullström, M.; Sundblad, G.; Bergström, U.; Downie, A.-L.; Lindegarth, M.; Mattila, J.

    2014-01-01

    Due to increasing pressure on the marine environment there is a growing need to understand species-environment relationships. To provide background for prioritising among variables (predictors) for use in distribution models, the relevance of predictors for benthic species was reviewed using the coastal Baltic Sea as a case-study area. Significant relationships for three response groups (fish, macroinvertebrates, macrovegetation) and six predictor categories (bottom topography, biotic features, hydrography, wave exposure, substrate and spatiotemporal variability) were extracted from 145 queried peer-reviewed field-studies covering three decades and six subregions. In addition, the occurrence of interaction among predictors was analysed. Hydrography was most often found in significant relationships, had low level of interaction with other predictors, but also had the most non-significant relationships. Depth and wave exposure were important in all subregions and are readily available, increasing their applicability for cross-regional modelling efforts. Otherwise, effort to model species distributions may prove challenging at larger scale as the relevance of predictors differed among both response groups and regions. Fish and hard bottom macrovegetation have the largest modelling potential, as they are structured by a set of predictors that at the same time are accurately mapped. A general importance of biotic features implies that these need to be accounted for in distribution modelling, but the mapping of most biotic features is challenging, which currently lowers the applicability. The presence of interactions suggests that predictive methods allowing for interactive effects are preferable. Detailing these complexities is important for future distribution modelling.

  6. Variation in the Distribution of Four Cacti Species Due to Climate Change in Chihuahua, Mexico

    Directory of Open Access Journals (Sweden)

    Leonor Cortes

    2013-12-01

    Full Text Available This study is about four cacti species in the state of Chihuahua, (Coryphantha macromeris, Mammillaria lasiacantha, Echinocereus dasyacanthus and Ferocactus wislizenii. Geographic distribution was inferred with MaxEnt. Projection was estimated under three scenarios simulated from IPCC (A2, B1 and A1B and four periods (2000, 2020, 2050 and 2080 with 19 climatic variables. MaxEnt projects a species decrease in 2020 under scenario A2, increasing in the following years. In 2080 all species, except E. dasyacanthus, will occupy a larger area than their current one. Scenario B1 projected for 2050 a decrease for all species, and in 2080 all species except E. dasyacanthus will increase their area. With A1B, C. macromeris decreases 27% from 2020 to 2050. E. dasyacanthus increases from 2020 to 2050 and decreases 73% from 2020 to 2080. M. lasiacantha decreases 13% from 2020 to 2080 and F. wislizenii will increase 13% from 2020 to 2080. Some species will remain stable on their areas despite climate changes, and other species may be affected under the conditions of the A1B scenario. It is important to continue with studies which give a broader perspective about the consequences of climate change, thus enabling decision-making about resource management.

  7. Spatial Distribution of Phlebotomine Sand Fly Species (Diptera: Psychodidae) in Qom Province, Central Iran.

    Science.gov (United States)

    Saghafipour, Abedin; Vatandoost, Hassan; Zahraei-Ramazani, Ali Reza; Yaghoobi-Ershadi, Mohammad Reza; Rassi, Yavar; Shirzadi, Mohammad Reza; Akhavan, Amir Ahmad

    2017-01-01

    Zoonotic cutaneous leishmaniasis (ZCL) is transmitted to humans by phlebotomine sand fly bites. ZCL is a major health problem in Iran, where basic knowledge gaps about sand fly species diversity persist in some ZCL-endemic areas. This paper describes the richness and spatial distribution of sand fly species, collected with sticky traps, in Qom province, a ZCL-endemic area in central Iran, where sand fly fauna has been poorly studied. Collected species were mapped on urban and rural digital maps based on a scale of 1/50,000. All analyses were undertaken with rural- and urban-level precision, i.e., rural and urban levels were our basic units of analysis. After identifying the sand flies, high-risk foci were determined. For spatial analysis of vector species population, the entomological sampling sites were geo-referenced using GPS. Arc GIS 9.3 software was used to determine the foci with leishmaniasis vector species. Following the analyses, two genera (Phlebotomus and Sergentomyia) and 14 species were identified. Based on the mapping and sand fly dispersion analysis, the rural districts were categorized into three groups-infection reported, without infection, and no report. Based on Geographical Information System analyses, Kahak and Markazi districts were identified as high-risk foci with leishmaniasis vector species. These findings can act as a help guide to direct active control measures to the identified high-risk foci and, eventually, lead to reduction in incidence of the disease. © Crown copyright 2016.

  8. Assessing distributions of two invasive species of contrasting habits in future climate.

    Science.gov (United States)

    Panda, Rajendra Mohan; Behera, Mukunda Dev; Roy, Partha Sarathi

    2017-12-28

    Understanding the impact of climate change on species invasion is crucial for sustainable biodiversity conservation. Through this study, we try to answer how species differing in phenological cycles, specifically Cassia tora and Lantana camara, differ in the manner in which they invade new regions in India in the future climate. Since both species occupy identical niches, exploring their invasive potential in different climate change scenarios will offer critical insights into invasion and inform ecosystem management. We use three modelling protocols (i.e., maximum entropy, generalised linear model and generalised additive model) to predict the current distribution. Projections are made for both moderate (A1B) and extreme (A2) IPCC (Intergovernmental Panel on Climate Change) scenarios for the year 2050 and 2100. The study reveals that the distributions of C. tora (annual) and L. camara (perennial) would depend on the precipitation of the warmest quarter and moisture availability. C. tora may demonstrate physiological tolerance to the mean diurnal temperature range and L. camara to the solar radiation. C. tora may invade central India, while L. camara may invade the Western Himalaya, parts of the Eastern Himalaya and the Western Ghats. The distribution ranges of both species could shift in the northern and north-eastern directions in India, owing to changes in moisture availability. The possible alterations in precipitation regimes could lead to water stress, which might have cascading effects on species invasion. L. camara might adapt to climate change better compared with C. tora. This comparative analysis of the future distributions of two invasive plants with contrasting habits demonstrates that temporal complementarity would prevail over the competition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Ecological and methodological drivers of species' distribution and phenology responses to climate change.

    Science.gov (United States)

    Brown, Christopher J; O'Connor, Mary I; Poloczanska, Elvira S; Schoeman, David S; Buckley, Lauren B; Burrows, Michael T; Duarte, Carlos M; Halpern, Benjamin S; Pandolfi, John M; Parmesan, Camille; Richardson, Anthony J

    2016-04-01

    Climate change is shifting species' distribution and phenology. Ecological traits, such as mobility or reproductive mode, explain variation in observed rates of shift for some taxa. However, estimates of relationships between traits and climate responses could be influenced by how responses are measured. We compiled a global data set of 651 published marine species' responses to climate change, from 47 papers on distribution shifts and 32 papers on phenology change. We assessed the relative importance of two classes of predictors of the rate of change, ecological traits of the responding taxa and methodological approaches for quantifying biological responses. Methodological differences explained 22% of the variation in range shifts, more than the 7.8% of the variation explained by ecological traits. For phenology change, methodological approaches accounted for 4% of the variation in measurements, whereas 8% of the variation was explained by ecological traits. Our ability to predict responses from traits was hindered by poor representation of species from the tropics, where temperature isotherms are moving most rapidly. Thus, the mean rate of distribution change may be underestimated by this and other global syntheses. Our analyses indicate that methodological approaches should be explicitly considered when designing, analysing and comparing results among studies. To improve climate impact studies, we recommend that (1) reanalyses of existing time series state how the existing data sets may limit the inferences about possible climate responses; (2) qualitative comparisons of species' responses across different studies be limited to studies with similar methodological approaches; (3) meta-analyses of climate responses include methodological attributes as covariates; and (4) that new time series be designed to include the detection of early warnings of change or ecologically relevant change. Greater consideration of methodological attributes will improve the accuracy

  10. Simulations inform design of regional occupancy-based monitoring for a sparsely distributed, territorial species.

    Science.gov (United States)

    Latif, Quresh S; Ellis, Martha M; Saab, Victoria A; Mellen-McLean, Kim

    2018-01-01

    Sparsely distributed species attract conservation concern, but insufficient information on population trends challenges conservation and funding prioritization. Occupancy-based monitoring is attractive for these species, but appropriate sampling design and inference depend on particulars of the study system. We employed spatially explicit simulations to identify minimum levels of sampling effort for a regional occupancy monitoring study design, using white-headed woodpeckers (Picoides albolvartus), a sparsely distributed, territorial species threatened by habitat decline and degradation, as a case study. We compared the original design with commonly proposed alternatives with varying targets of inference (i.e., species range, space use, or abundance) and spatial extent of sampling. Sampling effort needed to achieve adequate power to observe a long-term population trend (≥80% chance to observe a 2% yearly decline over 20 years) with the previously used study design consisted of annually monitoring ≥120 transects using a single-survey approach or ≥90 transects surveyed twice per year using a repeat-survey approach. Designs that shifted inference toward finer-resolution trends in abundance and extended the spatial extent of sampling by shortening transects, employing a single-survey approach to monitoring, and incorporating a panel design (33% of units surveyed per year) improved power and reduced error in estimating abundance trends. In contrast, efforts to monitor coarse-scale trends in species range or space use with repeat surveys provided extremely limited statistical power. Synthesis and applications. Sampling resolutions that approximate home range size, spatially extensive sampling, and designs that target inference of abundance trends rather than range dynamics are probably best suited and most feasible for broad-scale occupancy-based monitoring of sparsely distributed territorial animal species.

  11. Relationships among environmental variables and distribution of tree species at high elevation in the Olympic Mountains

    Science.gov (United States)

    Woodward, Andrea

    1998-01-01

    Relationships among environmental variables and occurrence of tree species were investigated at Hurricane Ridge in Olympic National Park, Washington, USA. A transect consisting of three plots was established down one north-and one south-facing slope in stands representing the typical elevational sequence of tree species. Tree species included subalpine fir (Abies lasiocarpa), Douglas-fir (Pseudotsuga menziesii), mountain hemlock (Tsuga mertensiana), and Pacific silver fir (Abies amabilis). Air and soil temperature, precipitation, and soil moisture were measured during three growing seasons. Snowmelt patterns, soil carbon and moisture release curves were also determined. The plots represented a wide range in soil water potential, a major determinant of tree species distribution (range of minimum values = -1.1 to -8.0 MPa for Pacific silver fir and Douglas-fir plots, respectively). Precipitation intercepted at plots depended on topographic location, storm direction and storm type. Differences in soil moisture among plots was related to soil properties, while annual differences at each plot were most often related to early season precipitation. Changes in climate due to a doubling of atmospheric CO2 will likely shift tree species distributions within, but not among aspects. Change will be buffered by innate tolerance of adult trees and the inertia of soil properties.

  12. Cylindrospermopsis raciborskii: review of the distribution, phylogeography, and ecophysiology of a global invasive species

    Science.gov (United States)

    Antunes, Jorge T.; Leão, Pedro N.; Vasconcelos, Vítor M.

    2015-01-01

    Cylindrospermopsis raciborskii is a cyanobacterial species extensively studied for its toxicity, bloom formation and invasiveness potential, which have consequences to public and environmental health. Its current geographical distribution, spanning different climates, suggests that C. raciborskii has acquired the status of a cosmopolitan species. From phylogeography studies, a tropical origin for this species seems convincing, with different conjectural routes of expansion toward temperate climates. This expansion may be a result of the species physiological plasticity, or of the existence of different ecotypes with distinct environmental requirements. In particular, C. raciborskii is known to tolerate wide temperature and light regimes and presents diverse nutritional strategies. This cyanobacterium is also thought to have benefited from climate change conditions, regarding its invasiveness into temperate climates. Other factors, recently put forward, such as allelopathy, may also be important to its expansion. The effect of C. raciborskii in the invaded communities is still mostly unknown but may strongly disturb species diversity at different trophic levels. In this review we present an up-to-date account of the distribution, phylogeography, ecophysiology, as well some preliminary reports of the impact of C. raciborskii in different organisms. PMID:26042108

  13. Climate change and species distribution: possible scenarios for thermophilic ticks in Romania

    Directory of Open Access Journals (Sweden)

    Cristian Domșa

    2016-05-01

    Full Text Available Several zoonotic tick-borne diseases are emerging in Europe due to various factors, including changes of the cultural landscape, increasing human populations, variation of social habits and climate change. We have modelled the potential range changes for two thermophilic tick species (Hyalomma marginatum and Rhipicephalus annulatus by use of MaxEnt® and 15 climatic predictors, taking into account the aptitude for future climatic change in Romania. Current models predict increased temperatures, both in the short term (up to 2050 and in the long term (up to 2070, together with possible changes also of the other climatic factors (e.g. precipitation, and may lead to higher zoonotic risks associated with an expansion of the range of the target species. Three different models were constructed (the present, 2050 and 2070 for four representative concentration pathways (RCPs of greenhouse gas scenarios: RCP2.6, RCP4.5, RCP6, and RCP8.5. The most dramatic scenario (RCP8.5 produced the highest increase in the probable distribution range for both species. In concordance with similar continental-wide studies, both tick species displayed a shift of distribution towards previously cooler areas of Romania. In most scenarios, this would lead to wider ranges; from 9.7 to 43.1% for H. marginatum, and from 53.4 to 205.2% for R annulatus. Although the developed models demonstrate a good predictive power, the issue of species ecology should also be considered.

  14. Climate, soil or both? Which variables are better predictors of the distributions of Australian shrub species?

    Science.gov (United States)

    Hageer, Yasmin; Esperón-Rodríguez, Manuel; Baumgartner, John B; Beaumont, Linda J

    2017-01-01

    Shrubs play a key role in biogeochemical cycles, prevent soil and water erosion, provide forage for livestock, and are a source of food, wood and non-wood products. However, despite their ecological and societal importance, the influence of different environmental variables on shrub distributions remains unclear. We evaluated the influence of climate and soil characteristics, and whether including soil variables improved the performance of a species distribution model (SDM), Maxent. This study assessed variation in predictions of environmental suitability for 29 Australian shrub species (representing dominant members of six shrubland classes) due to the use of alternative sets of predictor variables. Models were calibrated with (1) climate variables only, (2) climate and soil variables, and (3) soil variables only. The predictive power of SDMs differed substantially across species, but generally models calibrated with both climate and soil data performed better than those calibrated only with climate variables. Models calibrated solely with soil variables were the least accurate. We found regional differences in potential shrub species richness across Australia due to the use of different sets of variables. Our study provides evidence that predicted patterns of species richness may be sensitive to the choice of predictor set when multiple, plausible alternatives exist, and demonstrates the importance of considering soil properties when modeling availability of habitat for plants.

  15. Analyzing tropical forest tree species abundance distributions using a nonneutral model and through approximate Bayesian inference.

    Science.gov (United States)

    Jabot, Franck; Chave, Jérôme

    2011-08-01

    The neutral theory of biodiversity challenges the classical niche-based view of ecological communities, where species attributes and environmental conditions jointly determine community composition. Functional equivalence among species, as assumed by neutral ecological theory, has been recurrently falsified, yet many patterns of tropical tree communities appear consistent with neutral predictions. This may mean that neutral theory is a good first-approximation theory or that species abundance data sets contain too little information to reject neutrality. Here we present a simple test of neutrality based on species abundance distributions in ecological communities. Based on this test, we show that deviations from neutrality are more frequent than previously thought in tropical forest trees, especially at small spatial scales. We then develop a nonneutral model that generalizes Hubbell's dispersal-limited neutral model in a simple way by including one additional parameter of frequency dependence. We also develop a statistical method to infer the parameters of this model from empirical data by approximate Bayesian computation. In more than half of the permanent tree plots, we show that our new model fits the data better than does the neutral model. Finally, we discuss whether observed deviations from neutrality may be interpreted as the signature of environmental filtering on tropical tree species abundance distributions.

  16. The Analysis of Tree Species Distribution Information Extraction and Landscape Pattern Based on Remote Sensing Images

    Directory of Open Access Journals (Sweden)

    Yi Zeng

    2017-08-01

    Full Text Available The forest ecosystem is the largest land vegetation type, which plays the role of unreplacement with its unique value. And in the landscape scale, the research on forest landscape pattern has become the current hot spot, wherein the study of forest canopy structure is very important. They determines the process and the strength of forests energy flow, which influences the adjustments of ecosystem for climate and species diversity to some extent. The extraction of influencing factors of canopy structure and the analysis of the vegetation distribution pattern are especially important. To solve the problems, remote sensing technology, which is superior to other technical means because of its fine timeliness and large-scale monitoring, is applied to the study. Taking Lingkong Mountain as the study area, the paper uses the remote sensing image to analyze the forest distribution pattern and obtains the spatial characteristics of canopy structure distribution, and DEM data are as the basic data to extract the influencing factors of canopy structure. In this paper, pattern of trees distribution is further analyzed by using terrain parameters, spatial analysis tools and surface processes quantitative simulation. The Hydrological Analysis tool is used to build distributed hydrological model, and corresponding algorithm is applied to determine surface water flow path, rivers network and basin boundary. Results show that forest vegetation distribution of dominant tree species present plaque on the landscape scale and their distribution have spatial heterogeneity which is related to terrain factors closely. After the overlay analysis of aspect, slope and forest distribution pattern respectively, the most suitable area for stand growth and the better living condition are obtained.

  17. Testing species distribution models across space and time: high latitude butterflies and recent warming

    DEFF Research Database (Denmark)

    Eskildsen, Anne; LeRoux, Peter C.; Heikkinen, Risto K.

    2013-01-01

    changes at expanding range margins can be predicted accurately. Location. Finland. Methods. Using 10-km resolution butterfly atlas data from two periods, 1992–1999 (t1) and 2002–2009 (t2), with a significant between-period temperature increase, we modelled the effects of climatic warming on butterfly...... butterfly distributions under climate change. Model performance was lower with independent compared to non-independent validation and improved when land cover and soil type variables were included, compared to climate-only models. SDMs performed less well for highly mobile species and for species with long...

  18. Contribution to the knowledge of distribution of certain macrophytes, invasive and threatened species in Serbia

    Directory of Open Access Journals (Sweden)

    Jenačković, D.

    2015-12-01

    Full Text Available This paper contains a short report about new and unpublished chorological data for the following species: Hydrocharis morsus-ranae L., Bidens cernuus L., Najas marina L., Potamogeton lucens L., Schoenoplectus triqueter (L. Palla, Cyperus rotundus L., Polypogon monspeliensis (L. Desf. and Paspalum distichum L.. Despite the fact that this paper provides insight into the distribution of analyzed species, it could be used as a base for invasive species’ Paspalum distichum L. expanding patterns research, and as a base for reevaluation of the threatened status of Schoenoplectus triqueter (L. Palla and Cyperus rotundus L. in Serbia.

  19. Distribution of ddr (DNA damage response) genes among species of deinococcus

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang Yong; Jung, Sun Wook; Joe, Min Ho; Kim, Dong Ho [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-09-15

    The bacterium Deinococcus radiodurans is one of the most resistant organisms to the effects of ionizing radiation and other DNA-damaging agents. In this study, distributions of 10 ddr (DNA damage response) genes were investigated in 8 species of Deinocossus by polymerase chain reaction (PCR). We have compared the sequences of ddr genes of D. radiodurans, D. geothermalis and D. deserti, and selected primers which are suitable for the detection of ddr in different species of Deinococcus. A sequence homology search and PCR assay showed that ddrO, which encodes a global regulator of the radiation-desiccation response, was most well conserved in the Deinococcus lineage.

  20. Species richness and distributions of boreal waterbirds in relation to nesting and brood-rearing habitats

    Science.gov (United States)

    Lewis, Tyler L.; Lindberg, Mark S.; Schmutz, Joel A.; Bertram, Mark R.; Dubour, Adam J.

    2015-01-01

    Identification of ecological factors that drive animal distributions allows us to understand why distributions vary temporally and spatially, and to develop models to predict future changes to populations–vital tools for effective wildlife management and conservation. For waterbird broods in the boreal forest, distributions are likely driven by factors affecting quality of nesting and brood-rearing habitats, and the influence of these factors may extend beyond singles species, affecting the entire waterbird community. We used occupancy models to assess factors influencing species richness of waterbird broods on 72 boreal lakes, along with brood distributions of 3 species of conservation concern: lesser scaup (Aythya affinis), white-winged scoters (Melanitta fusca), and horned grebe (Podiceps auritus). Factors examined included abundance of invertebrate foods (Amphipoda, Diptera, Gastropoda, Hemiptera, Odonata), physical lake attributes (lake area, emergent vegetation), water chemistry (nitrogen, phosphorus, chlorophyll a concentrations), and nesting habitats (water edge, non-forest cover). Of the 5 invertebrates, only amphipod density was related to richness and occupancy, consistently having a large and positive relationship. Despite this importance to waterbirds, amphipods were the most patchily distributed invertebrate, with 17% of the study lakes containing 70% of collected amphipods. Lake area was the only other covariate that strongly and positively influenced species richness and occupancy of scaup, scoters, and grebes. All 3 water chemistry covariates, which provided alternative measures of lake productivity, were positively related to species richness but had little effect on scaup, scoter, and grebe occupancy. Conversely, emergent vegetation was negatively related to richness, reflecting avoidance of overgrown lakes by broods. Finally, nesting habitats had no influence on richness and occupancy, indicating that, at a broad spatial scale, brood

  1. Incorporating fragmentation and non-native species into distribution models to inform fluvial fish conservation.

    Science.gov (United States)

    Taylor, Andrew T; Papeş, Monica; Long, James M

    2018-02-01

    Fluvial fishes face increased imperilment from anthropogenic activities, but the specific factors contributing most to range declines are often poorly understood. For example, the range of the fluvial-specialist shoal bass (Micropterus cataractae) continues to decrease, yet how perceived threats have contributed to range loss is largely unknown. We used species distribution models to determine which factors contributed most to shoal bass range loss. We estimated a potential distribution based on natural abiotic factors and a series of currently occupied distributions that incorporated variables characterizing land cover, non-native species, and river fragmentation intensity (no fragmentation, dams only, and dams and large impoundments). We allowed interspecific relationships between non-native congeners and shoal bass to vary across fragmentation intensities. Results from the potential distribution model estimated shoal bass presence throughout much of their native basin, whereas models of currently occupied distribution showed that range loss increased as fragmentation intensified. Response curves from models of currently occupied distribution indicated a potential interaction between fragmentation intensity and the relationship between shoal bass and non-native congeners, wherein non-natives may be favored at the highest fragmentation intensity. Response curves also suggested that >100 km of interconnected, free-flowing stream fragments were necessary to support shoal bass presence. Model evaluation, including an independent validation, suggested that models had favorable predictive and discriminative abilities. Similar approaches that use readily available, diverse, geospatial data sets may deliver insights into the biology and conservation needs of other fluvial species facing similar threats. © 2017 Society for Conservation Biology.

  2. Biodiversity, distributions and adaptations of Arctic species in the context of environmental change.

    Science.gov (United States)

    Callaghan, Terry V; Björn, Lars Olof; Chernov, Yuri; Chapin, Terry; Christensen, Torben R; Huntley, Brian; Ims, Rolf A; Johansson, Margareta; Jolly, Dyanna; Jonasson, Sven; Matveyeva, Nadya; Panikov, Nicolai; Oechel, Walter; Shaver, Gus; Elster, Josef; Henttonen, Heikki; Laine, Kari; Taulavuori, Kari; Taulavuori, Erja; Zöckler, Christoph

    2004-11-01

    adapted to the Arctic's climate: some can metabolize at temperatures down to -39 degrees C. Cyanobacteria and algae have a wide range of adaptive strategies that allow them to avoid, or at least minimize UV injury. Microorganisms can tolerate most environmental conditions and they have short generation times which can facilitate rapid adaptation to new environments. In contrast, Arctic plant and animal species are very likely to change their distributions rather than evolve significantly in response to warming.

  3. The predictive skill of species distribution models for plankton in a changing climate

    DEFF Research Database (Denmark)

    Brun, Philipp Georg; Kiørboe, Thomas; Licandro, Priscilla

    2016-01-01

    Statistical species distribution models (SDMs) are increasingly used to project spatial relocations of marine taxa under future climate change scenarios. However, tests of their predictive skill in the real-world are rare. Here, we use data from the Continuous Plankton Recorder program, one...... of the longest running and most extensive marine biological monitoring programs, to investigate the reliability of predicted plankton distributions. We apply three commonly used SDMs to 20 representative plankton species, including copepods, diatoms, and dinoflagellates, all found in the North Atlantic....... Plankton may be particularly challenging to model, due to its short life span and the dispersive effects of constant water movements on all spatial scales, however there are few other studies against which to compare these results. We conclude that rigorous model validation, including comparison against...

  4. ECOLOGICAL CONDITIONS AND DISTRIBUTION OF GEMOR TREE SPECIES IN CENTRAL AND EAST KALIMANTAN

    Directory of Open Access Journals (Sweden)

    Wahyu C. Adinugroho

    2011-06-01

    Full Text Available The aim of this study was to determine the ecological conditions and distribution of gemor bark producing tree species at Tuanan village in Kapuas District, Central Kalimantan Province and Long Daliq village in Kutai Barat, East Kalimantan Province. In order to collect adequate vegetation data, several obser vation plots were laid out by using purposive sampling. Primary and secondary data were collected from the plot areas by obser ving directly the habitat and its ecological condition of vegetation. It was revealed that the gemor tree species tended to grow well on the habitats which have a thin layer of peat (< 2 m, pH 3 – 4 and in a humid climatic condition.  Two gemor bark producing tree species were identidfied in the study areas, namely Nothaphoebe coriacea (Kosterm. Kosterm. and  N. umbelliflora Blume. The similarity level of vegetation composition at both sites (Kapuas and Kutai Barat Districts was low. The tree species richness in the plot areas of Tuanan in Kapuas District, Central Kalimantan (82 species, 57 genera and 28 families was higher than that found in Long Daliq, Kutai Barat District, East Kalimantan (38 species, 26 genera and 19 families.

  5. [Species composition, distribution and phenological characters of pollen-allergenic plants in Beijing urban area].

    Science.gov (United States)

    Ouyang, Zhi-Yun; Xin, Jia-Nan; Zheng, Hua; Meng, Xue-Song; Wang, Xiao-Ke

    2007-09-01

    In order to know the species composition, distribution pattern, and phenological characteristics of pollen-allergenic plants in Beijing urban area, an investigation was made, combined with literature survey and experts interviews. The results showed that within the fifth ring of Beijing, there were 99 pollen-allergenic plant species belonging to 32 genera and 19 families, among which, 52 species were native plants, accounting for 52.5% of the total, 26 species were introduced from other regions of China, occupying 26.3% of the total, and 21 species were introduced from foreign countries, being 21.2% of the total. The 32 genera of pollen-allergenic plants in Beijing urban area were mainly North Temperate elements, occupying 40.6% , followed by Cosmopolitan and Pantropic elements. In all functional sections of Beijing urban area, the pollen-allergenic plants were most diversified in urban parks, and had the highest proportion in street tree species. The coverage of herbs with strong pollen allergy was in the order of waste lands > gym centers and institution yards > greenbelts > parks > residential areas > squares. The blooming period of pollen-allergenic arbors in Beijing urban area was concentrated in March and April, while that of pollen-allergenic herbs was from July to September.

  6. Morphology, Diet Composition, Distribution and Nesting Biology of Four Lark Species in Mongolia

    Directory of Open Access Journals (Sweden)

    Galbadrakh Mainjargal

    2013-12-01

    Full Text Available We aimed to enhance existing knowledge of four lark species (Mongolian lark , Horned lark, Eurasian skylark, and Lesser short-toed lark, with respect to nesting biology, distribution, and diet, using long-term dataset collected during 2000–2012. Nest and egg measurements substantially varied among species. For pooled data across species, the clutch size averaged 3.72 ± 1.13 eggs and did not differ among larks. Body mass of nestlings increased signi fi cantly with age at weighing. Daily increase in body mass of lark nestlings ranged between 3.09 and 3.89 gram per day. Unsurprisingly, the majority of lark locations occurred in steppe ecosystems, followed by human created systems; whereas only 1.8% of the pooled locations across species were observed in forest ecosystem. Diet composition did not vary among species in the proportions of major food categories consumed. The most commonly occurring food items were invertebrates and frequently consumed were being beetles (e.g. Coleoptera: Carabidae, Scarabaeidae, and Curculionidae and grasshoppers (e.g. Orthoptera: Acrididae, and their occurrences accounted for 63.7% of insect related food items. Among the fi ve morphological traits we measured, there were signi fi cant differences in wing span, body mass, bill, and tarsus; however tail lengths did not differ across four species.

  7. Determination of Algae and Macrophyte Species Distribution in Three Wastewater Stabilization Ponds Using Metagenomics Analysis

    OpenAIRE

    Wallace, Jack; Champagne, Pascale; Hall, Geof; Yin, Zhaochu; Liu, Xudong

    2015-01-01

    This study involved the evaluation of algae and macrophyte species distributions in three wastewater stabilization ponds (WSPs) at a wastewater treatment plant in Ontario, Canada, which has experienced high pH levels at the final effluent and excessive algae growth during the summer since 2003. From samples collected from the system, the relative abundances of specific algae and aquatic plant (macrophyte) taxa were assessed and correlated to water chemistry data. A strong shift from the domin...

  8. New distribution data of some Pontic and submediterranean plant species in Serbia

    Directory of Open Access Journals (Sweden)

    Tomović Gordana M.

    2003-01-01

    Full Text Available We present here the distribution of 11 rare Pontic and submediterranean plant species in Serbia based on field research, herbarium and literature data. These taxa were mapped on 10 x 10 km2 UTM grid. The following taxa were analyzed: Dianthus pinifolius Sibth. & Sm., Doronicum hungaricum Reichenb. fil., Sedum stefco Stefanov, Sempervivum zeleborii Schott, Trifolium pignantii Fauche & Chaub., Ranunculus illyricus L., Potentilla chrysantha Trev., Prunus tenella Batsch, Saxifraga bulbifera L., Linaria pelisseriana (L Miller and Gagea bohemica (Zausc Schul. & Schul.

  9. Modelling the spatial distribution of the nuisance mosquito species Anopheles plumbeus (Diptera: Culicidae) in the Netherlands.

    Science.gov (United States)

    Ibañez-Justicia, Adolfo; Cianci, Daniela

    2015-05-01

    Landscape modifications, urbanization or changes of use of rural-agricultural areas can create more favourable conditions for certain mosquito species and therefore indirectly cause nuisance problems for humans. This could potentially result in mosquito-borne disease outbreaks when the nuisance is caused by mosquito species that can transmit pathogens. Anopheles plumbeus is a nuisance mosquito species and a potential malaria vector. It is one of the most frequently observed species in the Netherlands. Information on the distribution of this species is essential for risk assessments. The purpose of the study was to investigate the potential spatial distribution of An. plumbeus in the Netherlands. Random forest models were used to link the occurrence and the abundance of An. plumbeus with environmental features and to produce distribution maps in the Netherlands. Mosquito data were collected using a cross-sectional study design in the Netherlands, from April to October 2010-2013. The environmental data were obtained from satellite imagery and weather stations. Statistical measures (accuracy for the occurrence model and mean squared error for the abundance model) were used to evaluate the models performance. The models were externally validated. The maps show that forested areas (centre of the Netherlands) and the east of the country were predicted as suitable for An. plumbeus. In particular high suitability and high abundance was predicted in the south-eastern provinces Limburg and North Brabant. Elevation, precipitation, day and night temperature and vegetation indices were important predictors for calculating the probability of occurrence for An. plumbeus. The probability of occurrence, vegetation indices and precipitation were important for predicting its abundance. The AUC value was 0.73 and the error in the validation was 0.29; the mean squared error value was 0.12. The areas identified by the model as suitable and with high abundance of An. plumbeus, are

  10. Incorporating plant fossil data into species distribution models is not straightforward: Pitfalls and possible solutions

    Science.gov (United States)

    Moreno-Amat, Elena; Rubiales, Juan Manuel; Morales-Molino, César; García-Amorena, Ignacio

    2017-08-01

    The increasing development of species distribution models (SDMs) using palaeodata has created new prospects to address questions of evolution, ecology and biogeography from wider perspectives. Palaeobotanical data provide information on the past distribution of taxa at a given time and place and its incorporation on modelling has contributed to advancing the SDM field. This has allowed, for example, to calibrate models under past climate conditions or to validate projected models calibrated on current species distributions. However, these data also bear certain shortcomings when used in SDMs that may hinder the resulting ecological outcomes and eventually lead to misleading conclusions. Palaeodata may not be equivalent to present data, but instead frequently exhibit limitations and biases regarding species representation, taxonomy and chronological control, and their inclusion in SDMs should be carefully assessed. The limitations of palaeobotanical data applied to SDM studies are infrequently discussed and often neglected in the modelling literature; thus, we argue for the more careful selection and control of these data. We encourage authors to use palaeobotanical data in their SDMs studies and for doing so, we propose some recommendations to improve the robustness, reliability and significance of palaeo-SDM analyses.

  11. Phenotypic distribution models corroborate species distribution models: A shift in the role and prevalence of a dominant prairie grass in response to climate change.

    Science.gov (United States)

    Smith, Adam B; Alsdurf, Jacob; Knapp, Mary; Baer, Sara G; Johnson, Loretta C

    2017-10-01

    Phenotypic distribution within species can vary widely across environmental gradients but forecasts of species' responses to environmental change often assume species respond homogenously across their ranges. We compared predictions from species and phenotype distribution models under future climate scenarios for Andropogon gerardii, a widely distributed, dominant grass found throughout the central United States. Phenotype data on aboveground biomass, height, leaf width, and chlorophyll content were obtained from 33 populations spanning a ~1000 km gradient that encompassed the majority of the species' environmental range. Species and phenotype distribution models were trained using current climate conditions and projected to future climate scenarios. We used permutation procedures to infer the most important variable for each model. The species-level response to climate was most sensitive to maximum temperature of the hottest month, but phenotypic variables were most sensitive to mean annual precipitation. The phenotype distribution models predict that A. gerardii could be largely functionally eliminated from where this species currently dominates, with biomass and height declining by up to ~60% and leaf width by ~20%. By the 2070s, the core area of highest suitability for A. gerardii is projected to shift up to ~700 km northeastward. Further, short-statured phenotypes found in the present-day short grass prairies on the western periphery of the species' range will become favored in the current core ~800 km eastward of their current location. Combined, species and phenotype models predict this currently dominant prairie grass will decline in prevalence and stature. Thus, sourcing plant material for grassland restoration and forage should consider changes in the phenotype that will be favored under future climate conditions. Phenotype distribution models account for the role of intraspecific variation in determining responses to anticipated climate change and

  12. Investigation of scavenging activities and distribution of paramagnetic species in Zanthoxylum limonella seeds.

    Science.gov (United States)

    Nakagawa, Kouichi; Promjareet, Apichet; Priprem, Aroonsri; Netweera, Vassana; Hara, Hideyuki

    2016-12-01

    We investigated the scavenging activities of methanol-extracted oil and the distribution of paramagnetic species in Zanthoxylum limonella (ZL) seeds using noninvasive 9 GHz electron paramagnetic resonance (EPR) imaging and continuous wave EPR. EPR detected three different stable paramagnetic species that were assigned to stable organic radicals, Mn 2+ , and other paramagnetic metal complexes. Two-dimensional EPR imaging showed that the stable paramagnetic species were located in the pigmented seed region with a strong intensity. Gas chromatography-mass spectrophotometric (GC-MS) analyses were then performed to identify the compound possibly related to the scavenging activity. The DPPH scavenging activities of ZL were slightly higher than those of Piper nigrum and Coriandrum sativum. Based on the results of EPR, GC-MS, and other methods, limonene in ZL is one of the major compounds that can be related to the scavenging activities.

  13. Fish species and community distributions as proxies for sea-floor habitat distributions: the Stellwagen Bank National Marine Sanctuary example (northwest Atlantic, Gulf Of Maine)

    Science.gov (United States)

    Auster, Peter J.; Joy, Kevin; Valentine, Page C.

    2001-01-01

    Defining the habitats of fishes and associated fauna on outer continental shelves is problematic given the paucity of data on the actual types and distributions of seafloor habitats. However many regions have good data on the distributions of fishes from resource surveys or catch statistics because of the economic importance of the fisheries. Fish distribution data (species or communities) have been used as a proxy for the distribution of habitats to develop precautionary conservation strategies for habitat protection (e.g., marine protected areas, fishing gear restrictions). In this study we assessed the relationships between the distributions of fish communities and species derived from trawl survey data with the spatial distribution of sediment types determined by sampling and acoustic reflectance derived from multibeam sonar surveys in Stellwagen Bank National Marine Sanctuary. Fish communities were correlated with reflectance values but all communities did not occur in unique sediment types. This suggests that use of community distributions as proxies for habitats should include the caveat that a greater number of communities within an area could indicate a greater range of habitat types. Single species distributions showed relationships between abundance and reflectance values. Trawl catches with low abundances had wide variations in reflectance values while those with high abundances had narrower ranges indicating habitat affinities. Significant non-random frequency-dependent relationships were observed for 17 of 20 species although only 12 of 20 species had significant relationships based on rank correlation. These results suggest that species distributions based on trawl survey data can be used as proxies for the distribution of seafloor habitats. Species with known habitat associations can be used to infer habitat requirements of co-occurring species and can be used to identify a range of habitat types.

  14. Fish species and community distributions as proxies for seafloor habitat distributions: The Stellwagen Bank National Marine Sanctuary example (Northwest Atlantic, Gulf of Maine)

    Science.gov (United States)

    Auster, P.J.; Joy, K.; Valentine, P.C.

    2001-01-01

    Defining the habitats of fishes and associated fauna on outer continental shelves is problematic given the paucity of data on the actual types and distributions of seafloor habitats. However many regions have good data on the distributions of fishes from resource surveys or catch statistics because of the economic importance of the fisheries. Fish distribution data (species or communities) have been used as a proxy for the distribution of habitats to develop precautionary conservation strategies for habitat protection (e.g., marine protected areas, fishing gear restrictions). In this study we assessed the relationships between the distributions of fish communities and species derived from trawl survey data with the spatial distribution of sediment types determined by sampling and acoustic reflectance derived from multibeam sonar surveys in Stellwagen Bank National Marine Sanctuary. Fish communities were correlated with reflectance values but all communities did not occur in unique sediment types. This suggests that use of community distributions as proxies for habitats should include the caveat that a greater number of communities within an area could indicate a greater range of habitat types. Single species distributions showed relationships between abundance and reflectance values. Trawl catches with low abundances had wide variations in reflectance values while those with high abundances had narrower ranges indicating habitat affinities. Significant non-random frequency-dependent relationships were observed for 17 of 20 species although only 12 of 20 species had significant relationships based on rank correlation. These results suggest that species distributions based on trawl survey data can be used as proxies for the distribution of seafloor habitats. Species with known habitat associations can be used to infer habitat requirements of co-occurring species and can be used to identify a range of habitat types.

  15. Zoogeographic distribution and habitat preferences of Orthoptera species (Insecta from Danube Delta Biosphere Reserve (Romania

    Directory of Open Access Journals (Sweden)

    Lupu Gabriel

    2013-12-01

    Full Text Available Arthropods belonging to the class Insecta, Orthoptera species, develop a variety of preferences towards the type of habitat impressive for most of the time. They inhabit the majority of latitudinal (from the equator to the Polar Regions near and altitudinal (from the dry areas below sea level and up to the alpine region biotopes. On the other hand, the species of Orthoptera are very diversified in terms of geographical spread, with all major types of distribution – from the endemic forms, characteristic only of a certain areas (exp.: Isophya dobrogensis until holopalearctic forms with a wide spread across Europe, North Africa and Asia, Palearctic (Gryllus campestris,Tettigonia viridissima, Gryllotalpa gryllotalpa, Tetrix tenuicornis, Calliptamus italicus, Oedipoda caerulescens, Aiolopus thalassinus, Chorthippus brunneus etc.. The Romanian ortopterofauna it was classified in 5 principal classes, each from these containing from 2 to 5 types of near zoogeographic elements: Palearctic, European, central-Asiatic-European, Mediterranean, and Carpatic elements. The classification is based on the fundamental types of distribution, group items from the biogeographic macrozoning of Europe, most of the time, however, taking into account the areas of interference of biogeographic place. Danube Delta Biosphere Reserve territory characterized by the presence of a single endemic species (Isophya dobrogensis on Popina Island constitute an impressive reservoir of spontaneous genetic resources for an area with a relatively small surface area,Orthoptera species with widespread (at national level in some cases finding here favorable conditions for the manifestation of the presence.

  16. [Comparative analysis of rDNA distribution in metaphase chromosomes of Cucurbitaceae species].

    Science.gov (United States)

    Xu, Yan-Hao; Yang, Fei; Cheng, You-Lin; Ma, Lu; Wang, Jian-Bo; Li, Li-Jia

    2007-05-01

    Fluorescence in situ hybridization (FISH) and double FISH experiments were carried out to ascertain the chromosomal distribution patterns of the 45S and 5S ribosomal DNAs in the three species of Cucurbitaceae. Five pairs of 45S rDNA loci and two pairs of 5S rDNA signals were detected on chromosomes of Cucurbita moschata Duch. Luffa cylindrical Roem. contained five pairs of 45S rDNA loci and one pair of 5S rDNA loci. In Benincasa hispida Cogn., two pairs of 45S rDNA sites and one pair of 5S rDNA site were detected. In this species, 5S rDNA and one pair of the 45S loci were collocated closely in chromosome 7S. 45S rDNA chromosomal distribution patterns were highly conserved among the three species, althoufh their number varied markedly. The 5S rDNA sites on chromosomes among the three species were highly polymorphic. We further discussed differentially evolutionary processes of 45S and 5S rDNA in plant genomes.

  17. Unveiling the species-rank abundance distribution by generalizing the Good-Turing sample coverage theory.

    Science.gov (United States)

    Chao, Anne; Hsieh, T C; Chazdon, Robin L; Colwell, Robert K; Gotelli, Nicholas J

    2015-05-01

    Based on a sample of individuals, we focus on inferring the vector of species relative abundance of an entire assemblage and propose a novel estimator of the complete species-rank abundance distribution (RAD). Nearly all previous estimators of the RAD use the conventional "plug-in" estimator Pi (sample relative abundance) of the true relative abundance pi of species i. Because most biodiversity samples are incomplete, the plug-in estimators are applied only to the subset of species that are detected in the sample. Using the concept of sample coverage and its generalization, we propose a new statistical framework to estimate the complete RAD by separately adjusting the sample relative abundances for the set of species detected in the sample and estimating the relative abundances for the set of species undetected in the sample but inferred to be present in the assemblage. We first show that P, is a positively biased estimator of pi for species detected in the sample, and that the degree of bias increases with increasing relative rarity of each species. We next derive a method to adjust the sample relative abundance to reduce the positive bias inherent in j. The adjustment method provides a nonparametric resolution to the longstanding challenge of characterizing the relationship between the true relative abundance in the entire assemblage and the observed relative abundance in a sample. Finally, we propose a method to estimate the true relative abundances of the undetected species based on a lower bound of the number of undetected species. We then combine the adjusted RAD for the detected species and the estimated RAD for the undetected species to obtain the complete RAD estimator. Simulation results show that the proposed RAD curve can unveil the true RAD and is more accurate than the empirical RAD. We also extend our method to incidence data. Our formulas and estimators are illustrated using empirical data sets from surveys of forest spiders (for abundance data) and

  18. Spatial Distribution Patterns in the Very Rare and Species-Rich Picea chihuahuana Tree Community (Mexico)

    Science.gov (United States)

    Wehenkel, Christian; Brazão-Protázio, João Marcelo; Carrillo-Parra, Artemio; Martínez-Guerrero, José Hugo; Crecente-Campo, Felipe

    2015-01-01

    The very rare Mexican Picea chihuahuana tree community covers an area of no more than 300 ha in the Sierra Madre Occidental. This special tree community has been the subject of several studies aimed at learning more about the genetic structure and ecology of the species and the potential effects of climate change. The spatial distribution of trees is a result of many ecological processes and can affect the degree of competition between neighbouring trees, tree density, variability in size and distribution, regeneration, survival, growth, mortality, crown formation and the biological diversity within forest communities. Numerous scale-dependent measures have been established in order to describe spatial forest structure. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. In this study, we examined the spatial distribution pattern of trees in the P. chihuahuana tree community in 12 localities, in relation to i) tree stand density, ii) diameter distribution (vertical structure), iii) tree species diversity, iv) geographical latitude and v) tree dominance at a fine scale (in 0.25 ha plots), with the aim of obtaining a better understanding of the complex ecosystem processes and biological diversity. Because of the strongly mixed nature of this tree community, which often produces low population densities of each tree species and random tree fall gaps caused by tree death, we expect aggregated patterns in individual Picea chihuahuana trees and in the P. chihuahuana tree community, repulsive Picea patterns to other tree species and repulsive patterns of young to adult trees. Each location was represented by one plot of 50 x 50 m (0.25 ha) established in the centre of the tree community. The findings demonstrate that the hypothesis of aggregated tree pattern is not applicable to the mean pattern measured by Clark-Evans index, Uniform Angle index and Mean Directional index of the uneven-aged P

  19. Spatial Distribution Patterns in the Very Rare and Species-Rich Picea chihuahuana Tree Community (Mexico.

    Directory of Open Access Journals (Sweden)

    Christian Wehenkel

    Full Text Available The very rare Mexican Picea chihuahuana tree community covers an area of no more than 300 ha in the Sierra Madre Occidental. This special tree community has been the subject of several studies aimed at learning more about the genetic structure and ecology of the species and the potential effects of climate change. The spatial distribution of trees is a result of many ecological processes and can affect the degree of competition between neighbouring trees, tree density, variability in size and distribution, regeneration, survival, growth, mortality, crown formation and the biological diversity within forest communities. Numerous scale-dependent measures have been established in order to describe spatial forest structure. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. In this study, we examined the spatial distribution pattern of trees in the P. chihuahuana tree community in 12 localities, in relation to i tree stand density, ii diameter distribution (vertical structure, iii tree species diversity, iv geographical latitude and v tree dominance at a fine scale (in 0.25 ha plots, with the aim of obtaining a better understanding of the complex ecosystem processes and biological diversity. Because of the strongly mixed nature of this tree community, which often produces low population densities of each tree species and random tree fall gaps caused by tree death, we expect aggregated patterns in individual Picea chihuahuana trees and in the P. chihuahuana tree community, repulsive Picea patterns to other tree species and repulsive patterns of young to adult trees. Each location was represented by one plot of 50 x 50 m (0.25 ha established in the centre of the tree community. The findings demonstrate that the hypothesis of aggregated tree pattern is not applicable to the mean pattern measured by Clark-Evans index, Uniform Angle index and Mean Directional index of the uneven

  20. Opportunistic citizen science data of animal species produce reliable estimates of distribution trends if analysed with occupancy models

    NARCIS (Netherlands)

    van Strien, A.J.; van Swaay, C.A.M.; Termaat, T.

    2013-01-01

    Many publications documenting large-scale trends in the distribution of species make use of opportunistic citizen data, that is, observations of species collected without standardized field protocol and without explicit sampling design. It is a challenge to achieve reliable estimates of distribution

  1. Remote sensing of the distribution and abundance of host species for spruce budworm in Northern Minnesota and Ontario

    Science.gov (United States)

    Peter T. Wolter; Philip A. Townsend; Brian R. Sturtevant; Clayton C. Kingdon

    2008-01-01

    Insects and disease affect large areas of forest in the U.S. and Canada. Understanding ecosystem impacts of such disturbances requires knowledge of host species distribution patterns on the landscape. In this study, we mapped the distribution and abundance of host species for the spruce budworm (Choristoneura fumiferana) to facilitate landscape scale...

  2. Plant species distribution in relation to water-table depth and soil redox potential in montane riparian meadows

    Science.gov (United States)

    Kathleen A. Dwire; J. Boone Kauffman; John E. Baham

    2006-01-01

    The distribution of riparian plant species is largely driven by hydrologic and soil variables, and riparian plant communities frequently occur in relatively distinct zones along streamside elevational and soil textural gradients. In two montane meadows in northeast Oregon, USA, we examined plant species distribution in three riparian plant communities¡ªdefined as wet,...

  3. Foliar Nutrient Distribution Patterns in Sympatric Maple Species Reflect Contrasting Sensitivity to Excess Manganese.

    Directory of Open Access Journals (Sweden)

    Denise R Fernando

    Full Text Available Sugar maple and red maple are closely-related co-occurring tree species significant to the North American forest biome. Plant abiotic stress effects including nutritional imbalance and manganese (Mn toxicity are well documented within this system, and are implicated in enhanced susceptibility to biotic stresses such as insect attack. Both tree species are known to overaccumulate foliar manganese (Mn when growing on unbuffered acidified soils, however, sugar maple is Mn-sensitive, while red maple is not. Currently there is no knowledge about the cellular sequestration of Mn and other nutrients in these two species. Here, electron-probe x-ray microanalysis was employed to examine cellular and sub-cellular deposition of excessively accumulated foliar Mn and other mineral nutrients in vivo. For both species, excess foliar Mn was deposited in symplastic cellular compartments. There were striking between-species differences in Mn, magnesium (Mg, sulphur (S and calcium (Ca distribution patterns. Unusually, Mn was highly co-localised with Mg in mesophyll cells of red maple only. The known sensitivity of sugar maple to excess Mn is likely linked to Mg deficiency in the leaf mesophyll. There was strong evidence that Mn toxicity in sugar maple is primarily a symplastic process. For each species, leaf-surface damage due to biotic stress including insect herbivory was compared between sites with acidified and non-acidified soils. Although it was greatest overall in red maple, there was no difference in biotic stress damage to red maple leaves between acidified and non-acidified soils. Sugar maple trees on buffered non-acidified soil were less damaged by biotic stress compared to those on unbuffered acidified soil, where they are also affected by Mn toxicity abiotic stress. This study concluded that foliar nutrient distribution in symplastic compartments is a determinant of Mn sensitivity, and that Mn stress hinders plant resistance to biotic stress.

  4. Proximal Soil Sensing - A Contribution for Species Habitat Distribution Modelling of Earthworms in Agricultural Soils?

    Science.gov (United States)

    Schirrmann, Michael; Joschko, Monika; Gebbers, Robin; Kramer, Eckart; Zörner, Mirjam; Barkusky, Dietmar; Timmer, Jens

    2016-01-01

    Earthworms are important for maintaining soil ecosystem functioning and serve as indicators of soil fertility. However, detection of earthworms is time-consuming, which hinders the assessment of earthworm abundances with high sampling density over entire fields. Recent developments of mobile terrestrial sensor platforms for proximal soil sensing (PSS) provided new tools for collecting dense spatial information of soils using various sensing principles. Yet, the potential of PSS for assessing earthworm habitats is largely unexplored. This study investigates whether PSS data contribute to the spatial prediction of earthworm abundances in species distribution models of agricultural soils. Proximal soil sensing data, e.g., soil electrical conductivity (EC), pH, and near infrared absorbance (NIR), were collected in real-time in a field with two management strategies (reduced tillage / conventional tillage) and sandy to loam soils. PSS was related to observations from a long-term (11 years) earthworm observation study conducted at 42 plots. Earthworms were sampled from 0.5 x 0.5 x 0.2 m³ soil blocks and identified to species level. Sensor data were highly correlated with earthworm abundances observed in reduced tillage but less correlated with earthworm abundances observed in conventional tillage. This may indicate that management influences the sensor-earthworm relationship. Generalized additive models and state-space models showed that modelling based on data fusion from EC, pH, and NIR sensors produced better results than modelling without sensor data or data from just a single sensor. Regarding the individual earthworm species, particular sensor combinations were more appropriate than others due to the different habitat requirements of the earthworms. Earthworm species with soil-specific habitat preferences were spatially predicted with higher accuracy by PSS than more ubiquitous species. Our findings suggest that PSS contributes to the spatial modelling of

  5. Climate change versus deforestation: Implications for tree species distribution in the dry forests of southern Ecuador.

    Science.gov (United States)

    Manchego, Carlos E; Hildebrandt, Patrick; Cueva, Jorge; Espinosa, Carlos Iván; Stimm, Bernd; Günter, Sven

    2017-01-01

    Seasonally dry forests in the neotropics are heavily threatened by a combination of human disturbances and climate change; however, the severity of these threats is seldom contrasted. This study aims to quantify and compare the effects of deforestation and climate change on the natural spatial ranges of 17 characteristic tree species of southern Ecuador dry deciduous forests, which are heavily fragmented and support high levels of endemism as part of the Tumbesian ecoregion. We used 660 plant records to generate species distribution models and land-cover data to project species ranges for two time frames: a simulated deforestation scenario from 2008 to 2014 with native forest to anthropogenic land-use conversion, and an extreme climate change scenario (CCSM4.0, RCP 8.5) for 2050, which assumed zero change from human activities. To assess both potential threats, we compared the estimated annual rates of species loss (i.e., range shifts) affecting each species. Deforestation loss for all species averaged approximately 71 km2/year, while potential climate-attributed loss was almost 21 km2/year. Moreover, annual area loss rates due to deforestation were significantly higher than those attributed to climate-change (P < 0.01). However, projections into the future scenario show evidence of diverging displacement patterns, indicating the potential formation of novel ecosystems, which is consistent with other species assemblage predictions as result of climate change. Furthermore, we provide recommendations for management and conservation, prioritizing the most threatened species such as Albizia multiflora, Ceiba trichistandra, and Cochlospermum vitifolium.

  6. {sup 137}Cs distribution among annual rings of different tree species contaminated after the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Soukhova, N.V.; Fesenko, S.V.; Klein, D.; Spiridonov, S.I.; Sanzharova, N.I.; Badot, P.M. E-mail: pierre-marie.badot@univ-fcomte.fr

    2003-07-01

    The distributions of {sup 137}Cs among annual rings of Pinus sylvestris and Betula pendula at four experimental sites located in the most contaminated areas in the Russian territory after the Chernobyl accident in 1986 were studied. Trees of different ages were sampled from four forest sites with different tree compositions and soil properties. The data analysis shows that {sup 137}Cs is very mobile in wood and the 1986 rings do not show the highest contamination. The difference between pine and birch in the pattern of radial {sup 137}Cs distribution can be satisfactorily explained by the difference in radial ray composition. {sup 137}Cs radial distribution in the wood can be described as the sum of two exponential functions for both species. The function parameters are height, age and species dependent. The distribution of {sup 137}Cs in birch wood reveals much more pronounced dependence on site characteristics and/or the age of trees than pines. The data obtained can be used to assess {sup 137}Cs content in wood.

  7. Digenean trematode species in the cockle Cerastodema edule: identification key and distribution along the north-eastern Atlantic shoreline

    DEFF Research Database (Denmark)

    Montaudouin, Xavier De; Thieltges, David W.; Gam, Mériame

    2009-01-01

    -scale distributional patterns of digenean species of the common cockle. At least sixteen digenean species, belonging to seven families, use cockles as intermediate host. Among these species two utilize cockles as first intermediate host only, whereas two species utilize cockles as both first and second intermediate...... host. The remaining eleven species have cockles as their second intermediate host. Water birds and fish are the definitive hosts to twelve and four species, respectively. Cockles are infected with digeneans along the latitudinal gradient from southern Morocco to the western region of the Barents Sea...... often with high infection levels. Whereas some of these digenean species occur along most of the latitudinal gradient others show a more restricted northern or southern distribution mostly caused by an underlying latitudinal gradient of host species. Knowledge of digenean species and their large...

  8. Species distribution modeling techniques as a tool in preliminary assessment of special nature reserve ,,Goč-Gvozdac’’

    Directory of Open Access Journals (Sweden)

    Čubrić, T.

    2016-09-01

    Full Text Available Effective conservation actions such as defining new nature reserve require accurate estimates of the spatial distributions of the target species. Species distribution models provide habitat suitability maps for studied species. In this paper we used Maxent software to estimate the distribution and extent of potential suitable habitat of five amphibian and reptilian species (Mesotriton alpestris, Bombina variegata, Testudo hermanni, Lacerta viridis and Vipera ammodytes in the special nature reserve “Goč-Gvozdac” (Central Serbia in order to assess how much of the potential habitats is included in this reserve. Comparing produced suitable habitat maps of the species with a map of the special nature reserve “Goč – Gvozdac” we concluded that the reserve boundaries do not coincide with the proposed distribution of suitable habitats for M. alpestris, T. hermanni, L. viridis and V. ammodytes, and therefore this reserve does not contribute much to the protection of local populations of these species.

  9. Ecological relationships of meso-scale distribution in 25 neotropical vertebrate species.

    Directory of Open Access Journals (Sweden)

    Lincoln José Michalski

    Full Text Available Vertebrates are a vital ecological component of Amazon forest biodiversity. Although vertebrates are a functionally important part of various ecosystem services they continue to be threatened by anthropogenic impacts throughout the Amazon. Here we use a standardized, regularly spaced arrangement of camera traps within 25km2 to provide a baseline assessment of vertebrate species diversity in a sustainable use protected area in the eastern Brazilian Amazon. We examined seasonal differences in the per species encounter rates (number of photos per camera trap and number of cameras with photos. Generalized linear models (GLMs were then used to examine the influence of five variables (altitude, canopy cover, basal area, distance to nearest river and distance to nearest large river on the number of photos per species and on functional groups. GLMs were also used to examine the relationships between large predators [Jaguar (Panthera onca and Puma (Puma concolor] and their prey. A total of 649 independent photos of 25 species were obtained from 1,800 camera trap days (900 each during wet and dry seasons. Only ungulates and rodents showed significant seasonal differences in the number of photos per camera. The number of photos differed between seasons for only three species (Mazama americana, Dasyprocta leporina and Myoprocta acouchy all of which were photographed more (3 to 10 fold increase during the wet season. Mazama americana was the only species where a significant difference was found in occupancy, with more photos in more cameras during the wet season. For most groups and species variation in the number of photos per camera was only explained weakly by the GLMs (deviance explained ranging from 10.3 to 54.4%. Terrestrial birds (Crax alector, Psophia crepitans and Tinamus major and rodents (Cuniculus paca, Dasyprocta leporina and M. acouchy were the notable exceptions, with our GLMs significantly explaining variation in the distribution of all

  10. Ecological Relationships of Meso-Scale Distribution in 25 Neotropical Vertebrate Species

    Science.gov (United States)

    Michalski, Lincoln José; Norris, Darren; de Oliveira, Tadeu Gomes; Michalski, Fernanda

    2015-01-01

    Vertebrates are a vital ecological component of Amazon forest biodiversity. Although vertebrates are a functionally important part of various ecosystem services they continue to be threatened by anthropogenic impacts throughout the Amazon. Here we use a standardized, regularly spaced arrangement of camera traps within 25km2 to provide a baseline assessment of vertebrate species diversity in a sustainable use protected area in the eastern Brazilian Amazon. We examined seasonal differences in the per species encounter rates (number of photos per camera trap and number of cameras with photos). Generalized linear models (GLMs) were then used to examine the influence of five variables (altitude, canopy cover, basal area, distance to nearest river and distance to nearest large river) on the number of photos per species and on functional groups. GLMs were also used to examine the relationships between large predators [Jaguar (Panthera onca) and Puma (Puma concolor)] and their prey. A total of 649 independent photos of 25 species were obtained from 1,800 camera trap days (900 each during wet and dry seasons). Only ungulates and rodents showed significant seasonal differences in the number of photos per camera. The number of photos differed between seasons for only three species (Mazama americana, Dasyprocta leporina and Myoprocta acouchy) all of which were photographed more (3 to 10 fold increase) during the wet season. Mazama americana was the only species where a significant difference was found in occupancy, with more photos in more cameras during the wet season. For most groups and species variation in the number of photos per camera was only explained weakly by the GLMs (deviance explained ranging from 10.3 to 54.4%). Terrestrial birds (Crax alector, Psophia crepitans and Tinamus major) and rodents (Cuniculus paca, Dasyprocta leporina and M. acouchy) were the notable exceptions, with our GLMs significantly explaining variation in the distribution of all species

  11. Ecological relationships of meso-scale distribution in 25 neotropical vertebrate species.

    Science.gov (United States)

    Michalski, Lincoln José; Norris, Darren; de Oliveira, Tadeu Gomes; Michalski, Fernanda

    2015-01-01

    Vertebrates are a vital ecological component of Amazon forest biodiversity. Although vertebrates are a functionally important part of various ecosystem services they continue to be threatened by anthropogenic impacts throughout the Amazon. Here we use a standardized, regularly spaced arrangement of camera traps within 25km2 to provide a baseline assessment of vertebrate species diversity in a sustainable use protected area in the eastern Brazilian Amazon. We examined seasonal differences in the per species encounter rates (number of photos per camera trap and number of cameras with photos). Generalized linear models (GLMs) were then used to examine the influence of five variables (altitude, canopy cover, basal area, distance to nearest river and distance to nearest large river) on the number of photos per species and on functional groups. GLMs were also used to examine the relationships between large predators [Jaguar (Panthera onca) and Puma (Puma concolor)] and their prey. A total of 649 independent photos of 25 species were obtained from 1,800 camera trap days (900 each during wet and dry seasons). Only ungulates and rodents showed significant seasonal differences in the number of photos per camera. The number of photos differed between seasons for only three species (Mazama americana, Dasyprocta leporina and Myoprocta acouchy) all of which were photographed more (3 to 10 fold increase) during the wet season. Mazama americana was the only species where a significant difference was found in occupancy, with more photos in more cameras during the wet season. For most groups and species variation in the number of photos per camera was only explained weakly by the GLMs (deviance explained ranging from 10.3 to 54.4%). Terrestrial birds (Crax alector, Psophia crepitans and Tinamus major) and rodents (Cuniculus paca, Dasyprocta leporina and M. acouchy) were the notable exceptions, with our GLMs significantly explaining variation in the distribution of all species

  12. Species distribution modeling for the invasive raccoon dog (Nyctereutes procyonoides) in Austria and first range predictions for alpine environments

    OpenAIRE

    Duscher Tanja; Nopp-Mayr Ursula

    2017-01-01

    Species distribution models are important tools for wildlife management planning, particularly in the case of invasive species. We employed a recent framework for niche-based invasive species distribution modeling to predict the probability of presence for the invasive raccoon dog (Nyctereutes procyonoides) in Austria. The raccoon dog is an adaptive, mobile and highly reproductive Asiatic canid that has successfully invaded many parts of Europe. It is known...

  13. The influence of electrohydrodynamic flow on the distribution of chemical species in positive corona

    Science.gov (United States)

    Pontiga, Francisco; Yanallah, Khelifa; Bouazza, R.; Chen, Junhong

    2015-09-01

    A numerical simulation of positive corona discharge in air, including the effect of electrohydrodynamic (EHD) motion of the gas, has been carried out. Air flow is assumed to be confined between two parallel plates, and corona discharge is produced around a thin wire, midway between the plates. Therefore, fluid dynamics equations, including electrical forces, have been solved together with the continuity equation of each neutral species. The plasma chemical model included 24 chemical reactions and ten neutral species, in addition to electrons and positive ions. The results of the simulation have shown that the influence of EHD flow on the spatial distributions of the species is quite different depending on the species. Hence, reactive species like atomic oxygen and atomic nitrogen are confined to the vicinity of the wire, and they are weakly affected by the EHD gas motion. In contrast, nitrogen oxides and ozone are efficiently dragged outside the active region of the corona discharge by the EHD flow. This work was supported by the Spanish Government Agency ``Ministerio de Ciencia e Innovación'' under Contract No. FIS2011-25161.

  14. Species Composition and Distribution of Adult Anopheles (Diptera: Culicidae) in Panama

    Science.gov (United States)

    LOAIZA, J. R.; BERMINGHAM, E.; SCOTT, M. E.; ROVIRA, J. R.; CONN, J. E.

    2010-01-01

    Anopheles (Diptera: Culicidae) species composition and distribution were studied using human landing catch data over a 35-yr period in Panama. Mosquitoes were collected from 77 sites during 228 field trips carried out by members of the National Malaria Eradication Service. Fourteen Anopheles species were identified. The highest average human biting rates were recorded from Anopheles (Nyssorhynchus) albimanus (Wiedemann) (9.8 bites/person/night) and Anopheles (Anopheles) punctimacula (Dyar and Knab) (6.2 bites/person/night). These two species were also the most common, present in 99.1 and 74.9%, respectively, of the sites. Anopheles (Nyssorhynchus) aquasalis (Curry) was encountered mostly in the indigenous Kuna Yala Comarca along the eastern Atlantic coast, where malaria case history and average human biting rate (9.3 bites/person/night) suggest a local role in malaria transmission. An. albimanus, An. punctimacula, and Anopheles (Anopheles) vestitipennis (Dyar and Knab) were more abundant during the rainy season (May–December), whereas An. aquasalis was more abundant in the dry season (January–April). Other vector species collected in this study were Anopheles (Kerteszia) neivai (Howard, Dyar, and Knab) and Anopheles (Anopheles) pseudopunctipennis s.l. (Theobald). High diversity of Anopheles species and six confirmed malaria vectors in endemic areas of Panama emphasize the need for more detailed studies to better understand malaria transmission dynamics. PMID:18826025

  15. Statics of deformable solids

    CERN Document Server

    Bisplinghoff, Raymond L; Pian, Theodore HH

    2014-01-01

    Profusely illustrated exposition of fundamentals of solid mechanics and principles of mechanics, statics, and simple statically indeterminate systems. Covers strain and stress in three-dimensional solids, elementary elasticity, energy principles in solid continuum, and more. 1965 edition.

  16. Modeling species distributions from heterogeneous data for the biogeographic regionalization of the European bryophyte flora.

    Directory of Open Access Journals (Sweden)

    Rubén G Mateo

    Full Text Available The definition of biogeographic regions provides a fundamental framework for a range of basic and applied questions in biogeography, evolutionary biology, systematics and conservation. Previous research suggested that environmental forcing results in highly congruent regionalization patterns across taxa, but that the size and number of regions depends on the dispersal ability of the taxa considered. We produced a biogeographic regionalization of European bryophytes and hypothesized that (1 regions defined for bryophytes would differ from those defined for other taxa due to the highly specific eco-physiology of the group and (2 their high dispersal ability would result in the resolution of few, large regions. Species distributions were recorded using 10,000 km2 MGRS pixels. Because of the lack of data across large portions of the area, species distribution models employing macroclimatic variables as predictors were used to determine the potential composition of empty pixels. K-means clustering analyses of the pixels based on their potential species composition were employed to define biogeographic regions. The optimal number of regions was determined by v-fold cross-validation and Moran's I statistic. The spatial congruence of the regions identified from their potential bryophyte assemblages with large-scale vegetation patterns is at odds with our primary hypothesis. This reinforces the notion that post-glacial migration patterns might have been much more similar in bryophytes and vascular plants than previously thought. The substantially lower optimal number of clusters and the absence of nested patterns within the main biogeographic regions, as compared to identical analyses in vascular plants, support our second hypothesis. The modelling approach implemented here is, however, based on many assumptions that are discussed but can only be tested when additional data on species distributions become available, highlighting the substantial

  17. Species distribution models: A comparison of statistical approaches for livestock and disease epidemics.

    Science.gov (United States)

    Hollings, Tracey; Robinson, Andrew; van Andel, Mary; Jewell, Chris; Burgman, Mark

    2017-01-01

    In livestock industries, reliable up-to-date spatial distribution and abundance records for animals and farms are critical for governments to manage and respond to risks. Yet few, if any, countries can afford to maintain comprehensive, up-to-date agricultural census data. Statistical modelling can be used as a proxy for such data but comparative modelling studies have rarely been undertaken for livestock populations. Widespread species, including livestock, can be difficult to model effectively due to complex spatial distributions that do not respond predictably to environmental gradients. We assessed three machine learning species distribution models (SDM) for their capacity to estimate national-level farm animal population numbers within property boundaries: boosted regression trees (BRT), random forests (RF) and K-nearest neighbour (K-NN). The models were built from a commercial livestock database and environmental and socio-economic predictor data for New Zealand. We used two spatial data stratifications to test (i) support for decision making in an emergency response situation, and (ii) the ability for the models to predict to new geographic regions. The performance of the three model types varied substantially, but the best performing models showed very high accuracy. BRTs had the best performance overall, but RF performed equally well or better in many simulations; RFs were superior at predicting livestock numbers for all but very large commercial farms. K-NN performed poorly relative to both RF and BRT in all simulations. The predictions of both multi species and single species models for farms and within hypothetical quarantine zones were very close to observed data. These models are generally applicable for livestock estimation with broad applications in disease risk modelling, biosecurity, policy and planning.

  18. Mechanical properties of sediment determine burrowing success and influence distribution of two lugworm species.

    Science.gov (United States)

    Crane, R L; Merz, R A

    2017-09-15

    We apply new perspectives on how organisms burrow by examining the association of in situ variation in sediment mechanical properties with burrowing ability and species distribution of two sympatric lugworms, Abarenicola pacifica and Abarenicola claparedi We quantified the sediment's resistance to penetration and its grain size distribution at sites inhabited by each species. Abarenicola pacifica individuals were found in significantly harder to penetrate, more heterogeneous sediments. We compared worm burrowing ability using reciprocal transplant experiments. Worms from firmer sediments, A. pacifica, were able to make successful steep burrows in sediments characteristic of either species. In contrast, A. claparedi individuals often failed to complete successful burrows in the firmer A. pacifica sediment. To examine how morphological differences could explain these patterns, we compared body wall musculature and measured how well individuals support their own bodies when draped over a cantilever. Lugworms from the firmer sediment had thicker body wall musculature and held their bodies more rigidly than did worms from softer sediments. Additionally, we observed subtle differences in the papillae on the proboscises' surfaces, which could affect worm-sediment interactions, but we found no differences in the chaetae of the two species. Abarenicola claparedi produced more mucus, which could be important in shoring up burrow walls in their shifting, sandy habitat. This study presents the first example of using field-based experiments to determine how sediment mechanical properties and worm burrowing ability could act to determine organismal distribution. Our findings have broader ecological implications because of the role of lugworms as ecosystem engineers. © 2017. Published by The Company of Biologists Ltd.

  19. Effects of future climate change and habitat loss in the distribution of frog species in the Ecuadorian Andes

    OpenAIRE

    Barrag?n Altamirano, Dayana Gabriela

    2015-01-01

    The biodiversity of the tropical Andes is threatened by climate change and habitat loss. Many studies have focused in the future effects of climate change on species distribution and conservation but few have included the effects habitat loss in their predictive studies. In this study we evaluated the combined effects of these two threats in the future distributions of endemic frogs species of the Ecuadorian Andes to the year 2050. We used ecological niche models to predict the distribution o...

  20. Implications of human induced changes on the distribution of important plant species in the northwestern coastal desert of Egypt

    Directory of Open Access Journals (Sweden)

    Marwa Waseem Halmy

    2015-12-01

    Full Text Available The application of species distribution modeling in deserts is a useful tool for mapping species and assessing the impact of human induced changes on individual species. Such applications are still rare, and this may be attributed to the fact that much of the arid lands and deserts around the world are located in inaccessible areas. Few studies have conducted spatially explicit modeling of plant species distribution in Egypt. The random forest modeling approach was applied to climatic and land-surface parameters to predict the distribution of ten important plant species in an arid landscape in the northwestern coastal desert of Egypt. The impact of changes in land use and climate on the distribution of the plant species was assessed. The results indicate that the changes in land use in the area have resulted in habitat loss for all the modeled species. Projected future changes in land use reveals that all the modeled species will continue to suffer habitat loss. The projected impact of modeled climate scenarios (A1B, A2A and B2A on the distribution of the modeled species by 2040 varied. Some of the species were projected to be adversely affected by the changes in climate, while other species are expected to benefit from these changes. The combined impact of the changes in land use and climate pose serious threats to most of the modeled species. The study found that all the species are expected to suffer loss in habitat, except Gymnocarpos decanderus. The study highlights the importance of assessing the impact of land use/climate change scenarios on other species of restricted distribution in the area and can help shape policy and mitigation measures directed toward biodiversity conservation in Egypt.

  1. Assessment of species diversity and distribution of an ancient diatom lineage using a DNA metabarcoding approach.

    Directory of Open Access Journals (Sweden)

    Deepak Nanjappa

    Full Text Available BACKGROUND: Continuous efforts to estimate actual diversity and to trace the species distribution and ranges in the natural environments have gone in equal pace with advancements of the technologies in the study of microbial species diversity from microscopic observations to DNA-based barcoding. DNA metabarcoding based on Next Generation Sequencing (NGS constitutes the latest advancement in these efforts. Here we use NGS data from different sites to investigate the geographic range of six species of the diatom family Leptocylindraceae and to identify possible new taxa within the family. METHODOLOGY/PRINCIPAL FINDINGS: We analysed the V4 and V9 regions of the nuclear-encoded SSU rDNA gene region in the NGS database of the European ERA-Biodiversa project BioMarKs, collected in plankton and sediments at six coastal sites in European coastal waters, as well as environmental sequences from the NCBI database. All species known in the family Leptocylindraceae were detected in both datasets, but the much larger Illumina V9 dataset showed a higher species coverage at the various sites than the 454 V4 dataset. Sequences identical or similar to the references of Leptocylindrus aporus, L. convexus, L. danicus/hargravesii and Tenuicylindrus belgicus were found in the Mediterranean Sea, North Atlantic Ocean and Black Sea as well as at locations outside Europe. Instead, sequences identical or close to that of L. minimus were found in the North Atlantic Ocean and the Black Sea but not in the Mediterranean Sea, while sequences belonging to a yet undescribed taxon were encountered only in Oslo Fjord and Baffin Bay. CONCLUSIONS/SIGNIFICANCE: Identification of Leptocylindraceae species in NGS datasets has expanded our knowledge of the species biogeographic distribution and of the overall diversity of this diatom family. Individual species appear to be widespread, but not all of them are found everywhere. Despite the sequencing depth allowed by NGS and the wide

  2. Diversity and Distribution of Cryptic Species of the Bemisia tabaci (Hemiptera: Aleyrodidae) complex in Pakistan.

    Science.gov (United States)

    Masood, Mariyam; Amin, Imran; Hassan, Ishtiaq; Mansoor, Shahid; Brown, Judith K; Briddon, Rob W

    2017-12-05

    Bemisia tabaci (Gennadius; Hempitera: Aleyrodidae) is considered to be a cryptic (sibling) species complex, the members of which exhibit morphological invariability while being genetically and behaviorally distinct. Members of the complex are agricultural pests that cause direct damage by feeding on plants, and indirectly by transmitting viruses that cause diseases leading to reduced crop yield and quality. In Pakistan, cotton leaf curl disease, caused by multiple begomovirus species, is the most economically important viral disease of cotton. In the study outlined here, the diversity and geographic distribution of B. tabaci cryptic species was investigated by analyzing a taxonomically informative fragment of the mitochondrial cytochrome c oxidase 1 gene (mtCOI-3'). The mtCOI-3' sequence was determined for 285 adult whiteflies and found to represent six cryptic species, the most numerous being Asia II-1 and Middle East Asia Minor 1 (MEAM-1), the later also referred to as the B-biotype, which was previously thought to be confined to Sindh province but herein, was also found to be present in the Punjab province. The endemic Asia I was restricted to Sindh province, while an individual in the Asia II-8 was identified in Pakistan for the first time. Also for the first time, samples were collected from northwestern Pakistan and Asia II-1 was identified. Results indicate that in Pakistan the overall diversity of B. tabaci cryptic species is high and, based on comparisons with findings from previous studies, the distribution is dynamic. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Modeling the effect of climate change on the distribution of oak and pine species of Mexico.

    Science.gov (United States)

    Gómez-Mendoza, Leticia; Arriaga, Laura

    2007-12-01

    We examined the vulnerability of 34 species of oaks (Quercus) and pines (Pinus) to the effects of global climate change in Mexico. We regionalized the HadCM2 model of climate change with local climatic data (mean annual temperature and rainfall) and downscaled the model with the inverse distance-weighted method. Databases of herbaria specimens, genetic algorithms (GARP), and digital covers of biophysical variables that affect oaks and pines were used to project geographic distributions of the species under a severe and conservative scenario of climate change for the year 2050. Starting with the current average temperature of 20.2 degrees C and average precipitation of 793 mm, under the severe warming scenario mean temperature and precipitation changed to 22.7 degrees C and 660 mm, respectively, in 2050. For the conservative warming scenario, these variables shifted to 21.8 degrees C and 721 mm. Responses to the different scenarios of climate change were predicted to be species-specific and related to each species climate affinity. The current geographic distribution of oaks and pines decreased 7-48% and 0.2-64%, respectively. The more vulnerable pines were Pinus rudis, P. chihuahuana, P. oocarpa, and P. culminicola, and the most vulnerable oaks were Quercus crispipilis, Q. peduncularis, Q. acutifolia, and Q. sideroxyla. In addition to habitat conservation, we think sensitive pine and oak species should be looked at more closely to define ex situ strategies (i.e., seed preservation in germplasm banks) for their long-term conservation. Modeling climatic-change scenarios is important to the development of conservation strategies.

  4. Decapod larvae distribution and species composition off the southern Portuguese coast

    Science.gov (United States)

    Pochelon, Patricia N.; Pires, Rita F. T.; Dubert, Jesús; Nolasco, Rita; Santos, A. Miguel P.; Queiroga, Henrique; dos Santos, Antonina

    2017-12-01

    For decapod crustaceans, the larval phase is the main responsible for dispersal, given the direct emission from adult habitats into the water column. Circulation patterns and behavioural mechanisms control the dispersal distance and connectivity between different areas. Information on larval distribution and abundance is required to predict the size and location of breeding populations, and correctly manage marine resources. Spatial distribution and abundance data of decapod larvae, and environmental parameters were assessed in winter surveys off the southern Portuguese coast. To better understand the oceanic structures driving larval distribution patterns, in situ physical parameters were measured and a hydrodynamical model used. Inter-annual, cross-shore and alongshore differences on decapod larvae distribution were found. Brachyuran crabs dominated the samples and similar taxa composition was observed in the most dynamic areas. Coastal taxa dominated the nearshore survey and were almost absent in the more offshore one, that registered much lower abundances. An upwelling front allowed a clear cross-shore species separation, also evident in the abundance values and number of taxa. Hydrodynamical conditions and adult habitats were the main factors explaining the observed patterns. Important missing information to understand the distribution patterns of decapod larval communities and the mechanisms behind them is given for the region.

  5. Continuous gene flow contributes to low global species abundance and distribution of a marine model diatom

    KAUST Repository

    Rastogi, Achal

    2017-08-15

    Unlike terrestrial ecosystems where geographical isolation often leads to a restricted gene flow between species, genetic admixing in aquatic micro-eukaryotes is likely to be frequent. Diatoms inhabit marine ecosystems since the Mesozoic period and presently constitute one of the major primary producers in the world ocean. They are a highly diversified group of eukaryotic phytoplankton with estimates of up to 200,000 species. Since decades, Phaeodactylum tricornutum is used as a model diatom species to characterize the functional pathways, physiology and evolution of diatoms in general. In the current study, using whole genome sequencing of ten P. tricornutum strains, sampled at broad geospatial and temporal scales, we show a continuous dispersal and genetic admixing between geographically isolated strains. We also describe a very high level of heterozygosity and propose it to be a consequence of frequent ancestral admixture. Our finding that P. tricornutum sequences are plausibly detectable at low but broadly distributed levels in the world ocean further suggests that high admixing between geographically isolated strains may create a significant bottleneck, thus influencing their global abundance and distribution in nature. Finally, in an attempt to understand the functional implications of genetic diversity between different P. tricornutum ecotypes, we show the effects of domestication in inducing changes in the selection pressure on many genes and metabolic pathways. We propose these findings to have significant implications for understanding the genetic structure of diatom populations in nature and provide a framework to assess the genomic underpinnings of their ecological success.

  6. A mixed modeling approach to predict the effect of environmental modification on species distributions.

    Directory of Open Access Journals (Sweden)

    Francesco Cozzoli

    Full Text Available Human infrastructures can modify ecosystems, thereby affecting the occurrence and spatial distribution of organisms, as well as ecosystem functionality. Sustainable development requires the ability to predict responses of species to anthropogenic pressures. We investigated the large scale, long term effect of important human alterations of benthic habitats with an integrated approach combining engineering and ecological modelling. We focused our analysis on the Oosterschelde basin (The Netherlands, which was partially embanked by a storm surge barrier (Oosterscheldekering, 1986. We made use of 1 a prognostic (numerical environmental (hydrodynamic model and 2 a novel application of quantile regression to Species Distribution Modeling (SDM to simulate both the realized and potential (habitat suitability abundance of four macrozoobenthic species: Scoloplos armiger, Peringia ulvae, Cerastoderma edule and Lanice conchilega. The analysis shows that part of the fluctuations in macrozoobenthic biomass stocks during the last decades is related to the effect of the coastal defense infrastructures on the basin morphology and hydrodynamics. The methodological framework we propose is particularly suitable for the analysis of large abundance datasets combined with high-resolution environmental data. Our analysis provides useful information on future changes in ecosystem functionality induced by human activities.

  7. Flea species infesting dogs in Spain: updated spatial and seasonal distribution patterns.

    Science.gov (United States)

    Gálvez, R; Montoya, A; Checa, R; Martín, O; Marino, V; Miró, G

    2017-03-01

    This entomological survey examines the spatial and seasonal distribution patterns of flea species infesting dogs in Spain. Bioclimatic zones covering broad climate and vegetation ranges were surveyed according to size. In a cross-sectional spatial survey carried out from late May 2013 to mid-July 2015, 1084 dogs from 42 different locations were examined. A total of 3032 fleas were collected and identified as belonging to the following species: Ctenocephalides felis (Siphonaptera: Pulicidae) (81.7%, 2476 fleas); Ctenocephalides canis (11.4%, 347 fleas); Pulex irritans (Siphonaptera: Pulicidae) (6.9%, 208 fleas), and Echidnophaga gallinacea (Siphonaptera: Pulicidae) (0.03%, one flea). Variables observed to have effects on flea abundance were animal weight, sex, length of hair and habitat. In the seasonal survey conducted from June 2014 to June 2015, 1014 fleas were collected from 239 dogs at 30 veterinary practices across Spain. Peaks in C. felis abundance were observed in early summer and late autumn, whereas high numbers of P. irritans and C. canis were recorded in autumn. Numbers of fleas detected in winter were low overall. Based on these findings, the present study updates the spatial and seasonal distributions of flea species in Spain and assesses the impacts of host and habitat variables on flea infestation. © 2016 The Royal Entomological Society.

  8. Diastereoisomer- and species-specific distribution of hexabromocyclododecane (HBCD) in fish and marine invertebrates.

    Science.gov (United States)

    Son, Min-Hui; Kim, Jongchul; Shin, Eun-Su; Seo, Sung-hee; Chang, Yoon-Seok

    2015-12-30

    The levels and distributional characteristics of hexabromocyclododecane (HBCD) diastereoisomers have been largely reported for various fish and select shellfish. In this study, we reclassified a number and variety of marine invertebrates, including shellfish, to further contribute to the comprehensive understanding of the effects and assessment of human exposure to HBCD. Overall, 30 marine invertebrate species (n=188) were investigated and the following order of ∑2HBCD (α- and γ-HBCD) was observed: fish>chordata>cephalopoda>echinodermata>bivalve>crustacea. The marine invertebrates that were reclassified into nektonic and benthic organisms showed similar concentration of ∑2HBCD. The feeding habits and modes of the marine organisms were considered to compare the degree of bioaccumulation and diastereoisomer-specific distribution of HBCD due to the effects of the environment in and around pollution sources, as well as the organisms' metabolic capacities. To the best of our knowledge, this is the first study to examine the species-specific distribution patterns of HBCD for both fish and marine invertebrates. We expect to significantly expand the understanding of the environmental fate of HBCD for marine organisms. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Effects of island area on plant species distribution and conservation implications in the Thousand Island Lake region

    OpenAIRE

    Que Sun; Jianbo Lu; Jianguo Wu; Fengfeng Zhang

    2008-01-01

    Numerous human activities have resulted in landscape fragmentation, and dam construction is one of them that often leads to drastic changes in biodiversity and ecosystem functioning on local and regional scales. In this study, we investigated how island area size affected the distribution of plant species in the Thousand Island Lake region. Also, we compared several conservation scenarios for maximizing plant species diversity. We found 56 tree species and 79 shrub species in 74 islands that ...

  10. Determination of the acute toxicity of Supaverm® to native and nonnative fish species of southwestern watersheds in static exposures

    Science.gov (United States)

    Schreier, Theresa M.; Hubert, Terrance D.

    2017-01-01

    Many fishes native to the Gila River Basin, Arizona, are on the decline with about 70 percent of the 17 fish species Federally listed as endangered or threatened. The decline has been partly attributed to the introduction of nonnative fishes that are of recreational interest such as catfish and smallmouth bass. Effective management practices are needed to control the nuisance nonnative fishes in Southwestern United States watersheds to prevent further decline of the native species and facilitate their restoration. An effective approach is the use of chemical toxicants to control the nuisance species. One chemical mixture of interest, Supaverm®, a combination of mebendazole and closantel, has been reported to show selectivity toward nonnative fish species of concern. We conducted acute toxicity tests on native and nonnative fish species of the Gila River (Arizona). Our findings showed that Supaverm® was not selectively toxic to the nonnative fish species suggesting that the use of the chemical mixture to eradicate those fish would not be effective.

  11. Trichoderma Biodiversity of Agricultural Fields in East China Reveals a Gradient Distribution of Species.

    Science.gov (United States)

    Jiang, Yuan; Wang, Jin-Liang; Chen, Jing; Mao, Li-Juan; Feng, Xiao-Xiao; Zhang, Chu-Long; Lin, Fu-Cheng

    2016-01-01

    We surveyed the Trichoderma (Hypocreales, Ascomycota) biodiversity in agricultural fields in four major agricultural provinces of East China. Trichoderma strains were identified based on molecular approaches and morphological characteristics. In three sampled seasons (spring, summer and autumn), 2078 strains were isolated and identified to 17 known species: T. harzianum (429 isolates), T. asperellum (425), T. hamatum (397), T. virens (340), T. koningiopsis (248), T. brevicompactum (73), T. atroviride (73), T. fertile (26), T. longibrachiatum (22), T. pleuroticola (16), T. erinaceum (16), T. oblongisporum (2), T. polysporum (2), T. spirale (2), T. capillare (2), T. velutinum (2), and T. saturnisporum (1). T. harzianum, T. asperellum, T. hamatum, and T. virens were identified as the dominant species with dominance (Y) values of 0.057, 0.052, 0.048, and 0.039, respectively. The species amount, isolate numbers and the dominant species of Trichoderma varied between provinces. Zhejiang Province has shown the highest diversity, which was reflected in the highest species amount (14) and the highest Shannon-Wiener diversity index of Trichoderma haplotypes (1.46). We observed that relative frequencies of T. hamatum and T. koningiopsis under rice soil were higher than those under wheat and maize soil, indicating the preference of Trichoderma to different crops. Remarkable seasonal variation was shown, with summer exhibiting the highest biodiversity of the studied seasons. These results show that Trichoderma biodiversity in agricultural fields varies by region, crop, and season. Zhejiang Province (the southernmost province in the investigated area) had more T. hamatum than Shandong Province (the northernmost province), not only in isolate amounts but also in haplotype amounts. Furthermore, at haplotype level, only T. hamatum showed a gradient distribution from south to north in correspondence analysis among the four dominant species. The above results would contribute to the

  12. Trichoderma Biodiversity of Agricultural Fields in East China Reveals a Gradient Distribution of Species.

    Directory of Open Access Journals (Sweden)

    Yuan Jiang

    Full Text Available We surveyed the Trichoderma (Hypocreales, Ascomycota biodiversity in agricultural fields in four major agricultural provinces of East China. Trichoderma strains were identified based on molecular approaches and morphological characteristics. In three sampled seasons (spring, summer and autumn, 2078 strains were isolated and identified to 17 known species: T. harzianum (429 isolates, T. asperellum (425, T. hamatum (397, T. virens (340, T. koningiopsis (248, T. brevicompactum (73, T. atroviride (73, T. fertile (26, T. longibrachiatum (22, T. pleuroticola (16, T. erinaceum (16, T. oblongisporum (2, T. polysporum (2, T. spirale (2, T. capillare (2, T. velutinum (2, and T. saturnisporum (1. T. harzianum, T. asperellum, T. hamatum, and T. virens were identified as the dominant species with dominance (Y values of 0.057, 0.052, 0.048, and 0.039, respectively. The species amount, isolate numbers and the dominant species of Trichoderma varied between provinces. Zhejiang Province has shown the highest diversity, which was reflected in the highest species amount (14 and the highest Shannon-Wiener diversity index of Trichoderma haplotypes (1.46. We observed that relative frequencies of T. hamatum and T. koningiopsis under rice soil were higher than those under wheat and maize soil, indicating the preference of Trichoderma to different crops. Remarkable seasonal variation was shown, with summer exhibiting the highest biodiversity of the studied seasons. These results show that Trichoderma biodiversity in agricultural fields varies by region, crop, and season. Zhejiang Province (the southernmost province in the investigated area had more T. hamatum than Shandong Province (the northernmost province, not only in isolate amounts but also in haplotype amounts. Furthermore, at haplotype level, only T. hamatum showed a gradient distribution from south to north in correspondence analysis among the four dominant species. The above results would contribute to the

  13. Distribution of periodontopathic bacterial species in Japanese children with developmental disabilities

    Directory of Open Access Journals (Sweden)

    Nemoto Hirotoshi

    2009-09-01

    Full Text Available Abstract Background Recent developments in molecular biological techniques have enabled rapid detection of periodontopathic bacterial species in clinical specimens. Accumulated evidence suggests that detection of specific bacterial species enables identification of subjects at high risk for the onset of periodontitis. We investigated the distribution of 10 selected periodontopathic bacterial species in dental plaque specimens obtained from children with disabilities who were attending daycare centers. Methods A total of 187 children (136 boys, 51 girls aged 1-6 years old and diagnosed with such disabilities as mental retardation, cerebral palsy, and autism, participated in the study. Subgingival dental plaque specimens were collected from the buccal side of the maxillary left second primary molar after a clinical examination. Bacterial DNA was extracted from the specimens and PCR analyses were carried out to detect 10 selected periodontopathic species using specific primers for each. In addition, statistical analyses were performed to analyze the correlations among clinical parameters and the detected species. Results The most frequently detected species was Capnocytophaga sputigena (28.3%, followed by Aggregatibacter actinomycetemcomitans (20.9% and Campylobacter rectus (18.2%. Eikenella corrodens, Capnocytophaga ochracea, and Prevotella nigrescence were detected in approximately 10% of the specimens, whereas Treponema denticola, Tannerella forsythia, and Prevotella intermedia were rarely found, and Porphyromonas gingivalis was not detected in any of the subjects. The total numbers of detected species were positively correlated with the age of the subjects. There were 10 subjects with positive reactions for T. denticola and/or T. forsythia, in whom the total number of bacterial species was significantly higher as compared to the other subjects. Furthermore, subjects possessing C. rectus showed significantly greater values for periodontal pocket

  14. Species Distribution Modeling between Abies koreana and Abies nephrolepis According to the RCP Scenarios in South Korea

    Science.gov (United States)

    Lee, S. G.; Kim, I. S.; Lee, W. K.; Kwon, H. J.; Byeon, J. G.; Yun, J. E.

    2016-12-01

    Vulnerable plant that includes species in crisis of extinction is shown by environment, competition between various species. The climate is one of the main factor that affect to the plant distribution. The most essential particular to make species distribution model is distribution data, and secondly environmental factors. 179 taxon plant classified according to the distribution, it consist of characteristic and regional distribution criteria. In case of climate data, 1960-1990 period made by World Clim Data is applied which has 0.86㎢ spatial resolution. It separates temperature and precipitation factor. To predict potential distribution, Maxent(Maximum Entropy Model) is applied that is widely known as suitable model in case of presence distributional data only. Among the target species, Abies koreana and Abies nephrolepis have no clearly key to identify, so their differences of distribution and environmental fator information could act useful. In order to know the distinction according to the classifying species, Abies koreana and Abies nephrolepis are typically selected. Abies koreana distributes at high mountain in Southern part of Korean Peninsula, otherwise Abies nephrolepis is at high mountain in from Middle latitude(over the 37°) in South Korea. These species has been the center of controversy recently, because the classification key of these species is not scientifically clear yet. In this perspective these species predicted potential distribution depend on whether these are same species or not. In the result of considering these species are same, entire predicted distribution area is wider, especially Jiri-san mountain(latitude : 35°) which is the highest latitude of the Abies koreana distributed point. On the other side, result of considering different species is shown that Abies koreana could climatically survive near by Soerak-san mountain(latitude : 37°), but Abies nephrolepis could not live in Halla-san mountan(33°) in Jeju-island which is the

  15. Comparison of biofilm ecology supporting growth of individual Naegleria species in a drinking water distribution system.

    Science.gov (United States)

    Puzon, Geoffrey J; Wylie, Jason T; Walsh, Tom; Braun, Kalan; Morgan, Matthew J

    2017-04-01

    Free-living amoebae (FLA) are common components of microbial communities in drinking water distribution systems (DWDS). FLA are of clinical importance both as pathogens and as reservoirs for bacterial pathogens, so identifying the conditions promoting amoebae colonisation of DWDSs is an important public health concern for water utilities. We used high-throughput amplicon sequencing to compare eukaryotic and bacterial communities associated with DWDS biofilms supporting distinct FLA species (Naegleria fowleri, N. lovaniensis or Vermamoeba sp.) at sites with similar physical/chemical conditions. Eukaryote and bacterial communities were characteristics of different FLA species presence, and biofilms supporting Naegleria growth had higher bacterial richness and higher abundance of Proteobacteria, Bacteroidetes (bacteria), Nematoda and Rotifera (eukaryota). The eukaryotic community in the biofilms had the greatest difference in relation to the presence of N. fowleri, while the bacterial community identified individual bacterial families associated with the presence of different Naegleria species. Our results demonstrate that ecogenomics data provide a powerful tool for studying the microbial and meiobiotal content of biofilms, and, in these samples can effectively discriminate biofilm communities supporting pathogenic N. fowleri. The identification of microbial species associated with N. fowleri could further be used in the management and control of N. fowleri in DWDS. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Quantifying Uncertainties from Presence Data Sampling Methods for Species Distribution Modeling: Focused on Vegetation.

    Science.gov (United States)

    Sung, S.; Kim, H. G.; Lee, D. K.; Park, J. H.; Mo, Y.; Kil, S.; Park, C.

    2016-12-01

    The impact of climate change has been observed throughout the globe. The ecosystem experiences rapid changes such as vegetation shift, species extinction. In these context, Species Distribution Model (SDM) is one of the popular method to project impact of climate change on the ecosystem. SDM basically based on the niche of certain species with means to run SDM present point data is essential to find biological niche of species. To run SDM for plants, there are certain considerations on the characteristics of vegetation. Normally, to make vegetation data in large area, remote sensing techniques are used. In other words, the exact point of presence data has high uncertainties as we select presence data set from polygons and raster dataset. Thus, sampling methods for modeling vegetation presence data should be carefully selected. In this study, we used three different sampling methods for selection of presence data of vegetation: Random sampling, Stratified sampling and Site index based sampling. We used one of the R package BIOMOD2 to access uncertainty from modeling. At the same time, we included BioCLIM variables and other environmental variables as input data. As a result of this study, despite of differences among the 10 SDMs, the sampling methods showed differences in ROC values, random sampling methods showed the lowest ROC value while site index based sampling methods showed the highest ROC value. As a result of this study the uncertainties from presence data sampling methods and SDM can be quantified.

  17. Distribution of endemic and introduced tick species in Free State Province, South Africa.

    Science.gov (United States)

    Horak, Ivan G; Jordaan, Adri J; Nel, Pierre J; van Heerden, Joseph; Heyne, Heloise; van Dalen, Ellie M

    2015-06-09

    The distributions of endemic tick vector species as well as the presence of species not endemic to Free State Province, South Africa, were determined during surveys or opportunistic collections from livestock, wildlife and vegetation. Amongst endemic ticks, the presence of Rhipicephalus appendiculatus was confirmed in the north of the province, whilst Rhipicephalus decoloratus was collected at 31 localities mostly in the centre and east, and Ixodes rubicundus at 11 localities in the south, south-west and centre of the province. Amongst the non-endemic species adult Amblyomma hebraeum were collected from white rhinoceroses (Ceratotherium simum) on four privately owned farms, whilst the adults of Rhipicephalus microplus were collected from cattle and a larva from vegetation at four localities in the east of the province. The collection of Rhipicephalus evertsi mimeticus from a sheep in the west of the province is the second record of its presence in the Free State, whereas the presence of Haemaphysalis silacea on helmeted guineafowl (Numida meleagris) and vegetation in the centre of the province represents a first record for this species in the Free State. The first collection of the argasid tick, Ornithodoros savignyi, in the Free State was made from a domestic cow and from soil in the west of the province. The localities at which the ticks were collected have been plotted and the ticks' role in the transmission or cause of disease in domestic livestock and wildlife is discussed.

  18. Distribution of endemic and introduced tick species in Free State Province, South Africa

    Directory of Open Access Journals (Sweden)

    Ivan G. Horak

    2015-03-01

    Full Text Available The distributions of endemic tick vector species as well as the presence of species not endemic to Free State Province, South Africa, were determined during surveys or opportunistic collections from livestock, wildlife and vegetation. Amongst endemic ticks, the presence of Rhipicephalus appendiculatus was confirmed in the north of the province, whilst Rhipicephalus decoloratus was collected at 31 localities mostly in the centre and east, and Ixodes rubicundus at 11 localities in the south, south-west and centre of the province. Amongst the non-endemic species adult Amblyomma hebraeum were collected from white rhinoceroses (Ceratotherium simum on four privately owned farms, whilst the adults of Rhipicephalus microplus were collected from cattle and a larva from vegetation at four localities in the east of the province. The collection of Rhipicephalus evertsi mimeticus from a sheep in the west of the province is the second record of its presence in the Free State, whereas the presence of Haemaphysalis silacea on helmeted guineafowl (Numida meleagris and vegetation in the centre of the province represents a first record for this species in the Free State. The first collection of the argasid tick, Ornithodoros savignyi, in the Free State was made from a domestic cow and from soil in the west of the province. The localities at which the ticks were collected have been plotted and the ticks’ role in the transmission or cause of disease in domestic livestock and wildlife is discussed.

  19. Uneven HAK/KUP/KT protein diversity among angiosperms: species distribution and perspectives

    Directory of Open Access Journals (Sweden)

    Manuel eNieves-Cordones

    2016-02-01

    Full Text Available HAK/KUP/KT K+ transporters have been widely associated with K+ transport across membranes in bacteria, fungi and plants. Indeed some members of the plant HAK/KUP/KT family contribute to root K+ uptake, notably at low external concentrations. Besides such role in acquisition, several studies carried out in Arabidopsis have shown that other members are also involved in developmental processes. With the publication of new plant genomes, a growing interest on plant species other than Arabidopsis has become evident. In order to understand HAK/KUP/KT diversity in these new plant genomes, we discuss the evolutionary trends of 913 HAK/KUP/KT sequences identified in 46 genomes revealing five major groups with an uneven distribution among angiosperms, notably between dicotyledonous and monocotyledonous species. This information evidenced the richness of crop genomes in HAK/KUP/KT transporters and supports their study for unraveling novel physiological roles of such transporters in plants.

  20. Mapping Regional Distribution of a Single Tree Species: Whitebark Pine in the Greater Yellowstone Ecosystem

    Directory of Open Access Journals (Sweden)

    Charles C. Schwartz

    2008-08-01

    Full Text Available Moderate resolution satellite imagery traditionally has been thought to be inadequate for mapping vegetation at the species level. This has made comprehensive mapping of regional distributions of sensitive species, such as whitebark pine, either impractical or extremely time consuming. We sought to determine whether using a combination of moderate resolution satellite imagery (Landsat Enhanced Thematic Mapper Plus, extensive stand data collected by land management agencies for other purposes, and modern statistical classification techniques (boosted classification trees could result in successful mapping of whitebark pine. Overall classification accuracies exceeded 90%, with similar individual class accuracies. Accuracies on a localized basis varied based on elevation. Accuracies also varied among administrative units, although we were not able to determine whether these differences related to inherent spatial variations or differences in the quality of available reference data.

  1. Assessing species distribution using Google Street View: a pilot study with the Pine Processionary Moth.

    Directory of Open Access Journals (Sweden)

    Jérôme Rousselet

    Full Text Available Mapping species spatial distribution using spatial inference and prediction requires a lot of data. Occurrence data are generally not easily available from the literature and are very time-consuming to collect in the field. For that reason, we designed a survey to explore to which extent large-scale databases such as Google maps and Google Street View could be used to derive valid occurrence data. We worked with the Pine Processionary Moth (PPM Thaumetopoea pityocampa because the larvae of that moth build silk nests that are easily visible. The presence of the species at one location can therefore be inferred from visual records derived from the panoramic views available from Google Street View. We designed a standardized procedure allowing evaluating the presence of the PPM on a sampling grid covering the landscape under study. The outputs were compared to field data. We investigated two landscapes using grids of different extent and mesh size. Data derived from Google Street View were highly similar to field data in the large-scale analysis based on a square grid with a mesh of 16 km (96% of matching records. Using a 2 km mesh size led to a strong divergence between field and Google-derived data (46% of matching records. We conclude that Google database might provide useful occurrence data for mapping the distribution of species which presence can be visually evaluated such as the PPM. However, the accuracy of the output strongly depends on the spatial scales considered and on the sampling grid used. Other factors such as the coverage of Google Street View network with regards to sampling grid size and the spatial distribution of host trees with regards to road network may also be determinant.

  2. Constraints on genome dynamics revealed from gene distribution among the Ralstonia solanacearum species.

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    Pierre Lefeuvre

    Full Text Available Because it is suspected that gene content may partly explain host adaptation and ecology of pathogenic bacteria, it is important to study factors affecting genome composition and its evolution. While recent genomic advances have revealed extremely large pan-genomes for some bacterial species, it remains difficult to predict to what extent gene pool is accessible within or transferable between populations. As genomes bear imprints of the history of the organisms, gene distribution pattern analyses should provide insights into the forces and factors at play in the shaping and maintaining of bacterial genomes. In this study, we revisited the data obtained from a previous CGH microarrays analysis in order to assess the genomic plasticity of the R. solanacearum species complex. Gene distribution analyses demonstrated the remarkably dispersed genome of R. solanacearum with more than half of the genes being accessory. From the reconstruction of the ancestral genomes compositions, we were able to infer the number of gene gain and loss events along the phylogeny. Analyses of gene movement patterns reveal that factors associated with gene function, genomic localization and ecology delineate gene flow patterns. While the chromosome displayed lower rates of movement, the megaplasmid was clearly associated with hot-spots of gene gain and loss. Gene function was also confirmed to be an essential factor in gene gain and loss dynamics with significant differences in movement patterns between different COG categories. Finally, analyses of gene distribution highlighted possible highways of horizontal gene transfer. Due to sampling and design bias, we can only speculate on factors at play in this gene movement dynamic. Further studies examining precise conditions that favor gene transfer would provide invaluable insights in the fate of bacteria, species delineation and the emergence of successful pathogens.

  3. Assessing species distribution using Google Street View: a pilot study with the Pine Processionary Moth.

    Science.gov (United States)

    Rousselet, Jérôme; Imbert, Charles-Edouard; Dekri, Anissa; Garcia, Jacques; Goussard, Francis; Vincent, Bruno; Denux, Olivier; Robinet, Christelle; Dorkeld, Franck; Roques, Alain; Rossi, Jean-Pierre

    2013-01-01

    Mapping species spatial distribution using spatial inference and prediction requires a lot of data. Occurrence data are generally not easily available from the literature and are very time-consuming to collect in the field. For that reason, we designed a survey to explore to which extent large-scale databases such as Google maps and Google Street View could be used to derive valid occurrence data. We worked with the Pine Processionary Moth (PPM) Thaumetopoea pityocampa because the larvae of that moth build silk nests that are easily visible. The presence of the species at one location can therefore be inferred from visual records derived from the panoramic views available from Google Street View. We designed a standardized procedure allowing evaluating the presence of the PPM on a sampling grid covering the landscape under study. The outputs were compared to field data. We investigated two landscapes using grids of different extent and mesh size. Data derived from Google Street View were highly similar to field data in the large-scale analysis based on a square grid with a mesh of 16 km (96% of matching records). Using a 2 km mesh size led to a strong divergence between field and Google-derived data (46% of matching records). We conclude that Google database might provide useful occurrence data for mapping the distribution of species which presence can be visually evaluated such as the PPM. However, the accuracy of the output strongly depends on the spatial scales considered and on the sampling grid used. Other factors such as the coverage of Google Street View network with regards to sampling grid size and the spatial distribution of host trees with regards to road network may also be determinant.

  4. Incorporating abundance information and guiding variable selection for climate-based ensemble forecasting of species' distributional shifts.

    Science.gov (United States)

    Tanner, Evan P; Papeş, Monica; Elmore, R Dwayne; Fuhlendorf, Samuel D; Davis, Craig A

    2017-01-01

    Ecological niche models (ENMs) have increasingly been used to estimate the potential effects of climate change on species' distributions worldwide. Recently, predictions of species abundance have also been obtained with such models, though knowledge about the climatic variables affecting species abundance is often lacking. To address this, we used a well-studied guild (temperate North American quail) and the Maxent modeling algorithm to compare model performance of three variable selection approaches: correlation/variable contribution (CVC), biological (i.e., variables known to affect species abundance), and random. We then applied the best approach to forecast potential distributions, under future climatic conditions, and analyze future potential distributions in light of available abundance data and presence-only occurrence data. To estimate species' distributional shifts we generated ensemble forecasts using four global circulation models, four representative concentration pathways, and two time periods (2050 and 2070). Furthermore, we present distributional shifts where 75%, 90%, and 100% of our ensemble models agreed. The CVC variable selection approach outperformed our biological approach for four of the six species. Model projections indicated species-specific effects of climate change on future distributions of temperate North American quail. The Gambel's quail (Callipepla gambelii) was the only species predicted to gain area in climatic suitability across all three scenarios of ensemble model agreement. Conversely, the scaled quail (Callipepla squamata) was the only species predicted to lose area in climatic suitability across all three scenarios of ensemble model agreement. Our models projected future loss of areas for the northern bobwhite (Colinus virginianus) and scaled quail in portions of their distributions which are currently areas of high abundance. Climatic variables that influence local abundance may not always scale up to influence species

  5. Diversification Rates and the Evolution of Species Range Size Frequency Distribution

    Directory of Open Access Journals (Sweden)

    Silvia Castiglione

    2017-11-01

    Full Text Available The geographic range sizes frequency distribution (RFD within clades is typically right-skewed with untransformed data, and bell-shaped or slightly left-skewed under the log-transformation. This means that most species within clades occupy diminutive ranges, whereas just a few species are truly widespread. A number of ecological and evolutionary explanations have been proposed to account for this pattern. Among the latter, much attention has been given to the issue of how extinction and speciation probabilities influence RFD. Numerous accounts now convincingly demonstrate that extinction rate decreases with range size, both in living and extinct taxa. The relationship between range size and speciation rate, though, is much less obvious, with either small or large ranged species being proposed to originate more daughter taxa. Herein, we used a large fossil database including 21 animal clades and more than 80,000 fossil occurrences distributed over more than 400 million years of marine metazoans (exclusive of vertebrates evolution, to test the relationship between extinction rate, speciation rate, and range size. As expected, we found that extinction rate almost linearly decreases with range size. In contrast, speciation rate peaks at the large (but not the largest end of the range size spectrum. This is consistent with the peripheral isolation mode of allopatric speciation being the main mechanism of species origination. The huge variation in phylogeny, fossilization potential, time of fossilization, and the overarching effect of mass extinctions suggest caution must be posed at generalizing our results, as individual clades may deviate significantly from the general pattern.

  6. A new species of Desmopachria Babington (Coleoptera: Dytiscidae) from Cuba with a prediction of its geographic distribution and notes on other Cuban species of the genus.

    Science.gov (United States)

    Megna, Yoandri S; Sánchez-Fernández, David

    2014-01-10

    A new species, Desmopachria andreae sp. n. is described from Cuba. Diagnostic characters including illustrations of male genitalia are provided and illustrated for the five species of the genus occurring on the island. For these five species both a simple key to adults and maps of their known distribution in Cuba are also provided. Using a Maximun Entropy method (MaxEnt), a distribution model was developed for D. andreae sp.n. Based on the model's predictions, this species has a higher probability of occurring in high altitude forests (above 1000 m a.s.l.), characterised by relatively low temperatures especially during the hottest and wettest seasons, specifically, the mountainous areas of the Macizo de Guamuhaya (Central Cuba), Sierra Maestra (S Cuba) and Nipe-Sagua-Baracoa (NE Cuba). In some of these areas the species has not yet been recorded, and should be searched for in future field surveys.

  7. Distribution pattern of dorsal root ganglion neurons synthesizing nitric oxide synthase in different animal species.

    Science.gov (United States)

    Kolesár, Dalibor; Kolesárová, Mária; Kyselovič, Ján

    2017-04-01

    The main aim of the present review is to provide at first a short survey of the basic anatomical description of sensory ganglion neurons in relation to cell size, conduction velocity, thickness of myelin sheath, and functional classification of their processes. In addition, we have focused on discussing current knowledge about the distribution pattern of neuronal nitric oxide synthase containing sensory neurons especially in the dorsal root ganglia in different animal species; hence, there is a large controversy in relation to interpretation of the results dealing with this interesting field of research.

  8. Levels and distribution of organohalogenated contaminants in 5 fish species from Sir Dam Lake, Kahramanmaras, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Erdogrul, Oe. [Faculty of Agriculture, Kahramanmaras (Turkey). Dept. of Food Engineering; Covaci, A.; Schepens, P. [Antwerp Univ. (Belgium). Toxicological Center

    2004-09-15

    In Turkey, OCPs have been used since 1945, with large quantities of these chemicals being used during the 1960s and 1970s. Since 1983, the usage of OCPs has been severely restricted or banned. Only few studies have investigated the presence of OCPs in Turkish aquatic environment, where they have been evidenced in relatively high concentrations. The aim of this study was to investigate the levels and distribution of organohalogenated contaminants in several fish species from Syr Dam Lake (Kahramanmarab, Turkey), an artificial lake with great economical importance for the region.

  9. Particle size distribution of major inorganic species in atmospheric aerosols from Majorca (Spain).

    Science.gov (United States)

    Mateu, J.; Forteza, R.; Cerdà, V.; Colom-Altés, M.

    1995-09-01

    Atmospheric aerosols collected by means of a cascade impaction system at the campus of the University of the Balearic Islands (Majorca, Spain) from November 1993 to February 1994 were analysed for chloride, nitrate, sulphate, ammonium, calcium, magnesium, sodium and potassium. Based on particle size distribution, the species studied were classified into three groups: (a) concentration decrease with particle size (sulphate and ammonium), (b) concentration increase with particle size (chloride, calcium, magnesium and sodium), and ( c) independent of particle size (nitrate and potassium). A principal component analysis (PCA) revealed a clear relationship between particle size and analyte origin. Also, the origin of sulphate and potassium fine and coarse particles was found to be different.

  10. Distribution of the species Matthiola fruticulosa (L.) Maire (Brassicaceae) in Croatia

    OpenAIRE

    Šegota, Vedran; Jasprica, Nenad; Bogdanović, Sandro; Pandža, Marija; Milović, Milenko; Alegro, Antun

    2016-01-01

    This paper presents the distribution of the rare plant species Matthiola fruticulosa (L.) Maire in Croatia. During our study, previous records on the Pelješac peninsula were confirmed, and new records were found, extending the Croatian areal to the southern U radu se analizira rasprostranjenost rijetke biljne vrste Matthiola fruticulosa (L.) Maire u Hrvatskoj. Tijekom našeg istraživanja potvrđena su prethodna nalazišta vrste na Pelješcu, a nova nalazišta su proširila areal vrste u Hrvatskoj s...

  11. [Distribution of fine root biomass of main planting tree species in Loess Plateau, China].

    Science.gov (United States)

    Jian, Sheng-Qi; Zhao, Chuan-Yan; Fang, Shu-Min; Yu, Kai

    2014-07-01

    The distribution of fine roots of Pinus tabuliformis, Populus tomentosa, Prunus armeniaca, Robinia pseudoacacia, Hippophae rhamnoides, and Caragana korshinskii was investigated by using soil core method and the fine root was defined as root with diameter less than 2 mm. The soil moisture and soil properties were measured. The results showed that in the horizontal direction, the distribution of fine root biomass of P. tabuliformis presented a conic curve, and the fine root biomass of the other species expressed logarithm correlation. Radial roots developed, the fine root biomass were concentrated within the scope of the 2-3 times crown, indicating that trees extended their roots laterally to seek water farther from the tree. In the vertical direction, the fine root biomass decreased with the increasing soil depth. Fine root biomass had significant negative correlation with soil water content and bulk density, while significant positive correlation with organic matter and total N contents.

  12. Explaining local-scale species distributions: relative contributions of spatial autocorrelation and landscape heterogeneity for an avian assemblage.

    Science.gov (United States)

    Mattsson, Brady J; Zipkin, Elise F; Gardner, Beth; Blank, Peter J; Sauer, John R; Royle, J Andrew

    2013-01-01

    Understanding interactions between mobile species distributions and landcover characteristics remains an outstanding challenge in ecology. Multiple factors could explain species distributions including endogenous evolutionary traits leading to conspecific clustering and endogenous habitat features that support life history requirements. Birds are a useful taxon for examining hypotheses about the relative importance of these factors among species in a community. We developed a hierarchical Bayes approach to model the relationships between bird species occupancy and local landcover variables accounting for spatial autocorrelation, species similarities, and partial observability. We fit alternative occupancy models to detections of 90 bird species observed during repeat visits to 316 point-counts forming a 400-m grid throughout the Patuxent Wildlife Research Refuge in Maryland, USA. Models with landcover variables performed significantly better than our autologistic and null models, supporting the hypothesis that local landcover heterogeneity is important as an exogenous driver for species distributions. Conspecific clustering alone was a comparatively poor descriptor of local community composition, but there was evidence for spatial autocorrelation in all species. Considerable uncertainty remains whether landcover combined with spatial autocorrelation is most parsimonious for describing bird species distributions at a local scale. Spatial structuring may be weaker at intermediate scales within which dispersal is less frequent, information flows are localized, and landcover types become spatially diversified and therefore exhibit little aggregation. Examining such hypotheses across species assemblages contributes to our understanding of community-level associations with conspecifics and landscape composition.

  13. Explaining local-scale species distributions: relative contributions of spatial autocorrelation and landscape heterogeneity for an avian assemblage.

    Directory of Open Access Journals (Sweden)

    Brady J Mattsson

    Full Text Available Understanding interactions between mobile species distributions and landcover characteristics remains an outstanding challenge in ecology. Multiple factors could explain species distributions including endogenous evolutionary traits leading to conspecific clustering and endogenous habitat features that support life history requirements. Birds are a useful taxon for examining hypotheses about the relative importance of these factors among species in a community. We developed a hierarchical Bayes approach to model the relationships between bird species occupancy and local landcover variables accounting for spatial autocorrelation, species similarities, and partial observability. We fit alternative occupancy models to detections of 90 bird species observed during repeat visits to 316 point-counts forming a 400-m grid throughout the Patuxent Wildlife Research Refuge in Maryland, USA. Models with landcover variables performed significantly better than our autologistic and null models, supporting the hypothesis that local landcover heterogeneity is important as an exogenous driver for species distributions. Conspecific clustering alone was a comparatively poor descriptor of local community composition, but there was evidence for spatial autocorrelation in all species. Considerable uncertainty remains whether landcover combined with spatial autocorrelation is most parsimonious for describing bird species distributions at a local scale. Spatial structuring may be weaker at intermediate scales within which dispersal is less frequent, information flows are localized, and landcover types become spatially diversified and therefore exhibit little aggregation. Examining such hypotheses across species assemblages contributes to our understanding of community-level associations with conspecifics and landscape composition.

  14. A spatial pattern analysis of the halophytic species distribution in an arid coastal environment.

    Science.gov (United States)

    Badreldin, Nasem; Uria-Diez, J; Mateu, J; Youssef, Ali; Stal, Cornelis; El-Bana, Magdy; Magdy, Ahmed; Goossens, Rudi

    2015-05-01

    Obtaining information about the spatial distribution of desert plants is considered as a serious challenge for ecologists and environmental modeling due to the required intensive field work and infrastructures in harsh and remote arid environments. A new method was applied for assessing the spatial distribution of the halophytic species (HS) in an arid coastal environment. This method was based on the object-based image analysis for a high-resolution Google Earth satellite image. The integration of the image processing techniques and field work provided accurate information about the spatial distribution of HS. The extracted objects were based on assumptions that explained the plant-pixel relationship. Three different types of digital image processing techniques were implemented and validated to obtain an accurate HS spatial distribution. A total of 2703 individuals of the HS community were found in the case study, and approximately 82% were located above an elevation of 2 m. The micro-topography exhibited a significant negative relationship with pH and EC (r = -0.79 and -0.81, respectively, p processes, in particular a hybrid family of Gibbs processes. A new model is proposed that uses a hard-core structure at very short distances, together with a cluster structure in short-to-medium distances and a Poisson structure for larger distances. This model was found to fit the data perfectly well.

  15. SESAM – a new framework integrating macroecological and species distribution models for predicting spatio-temporal patterns of species assemblages

    DEFF Research Database (Denmark)

    Guisan, Antoine; Rahbek, Carsten

    2011-01-01

    with constituent species to approximate the properties of assemblages. Here, we propose to unify the two approaches in a single ‘spatially explicit species assemblage modelling’ (SESAM) framework. This framework uses relevant designations of initial species source pools for modelling, macroecological variables...

  16. The Prosobranchia (Gastropoda: Mollusca) Species of Turkey and Their Zoogeographic Distribution 1. Fresh and Brackish Water

    OpenAIRE

    YILDIRIM, M. Zeki

    2014-01-01

    Of the Prosobranchia species found in Turkey, 60 species and 12 subspecies were determined to be present in the study area according to our results and the results of foreign malacologists. The species and their genera are: 8 species, 2 subspecies belonging to Theodoxus; 1 species, 1 subspecies belonging to Viviparus; 4 species belonging to Valvata; 3 species belonging to Hydrobia; 1 species belonging to Semisalsa; 6 species belonging to Graecoanatolica; 2 species belonging to Kirelia; 2 s...

  17. Occurrence and distribution of soil Fusarium species under wheat crop in zero tillage

    Energy Technology Data Exchange (ETDEWEB)

    Silvestro, L. B.; Stenglein, S. A.; Forjan, H.; Dinolfo, M. I.; Aramburri, A. M.; Manso, L.; Moreno, M. V.

    2013-05-01

    The presence of Fusarium species in cultivated soils is commonly associated with plant debris and plant roots. Fusarium species are also soil saprophytes. The aim of this study was to examine the occurrence and distribution of soil Fusarium spp. at different soil depths in a zero tillage system after the wheat was harvested. Soil samples were obtained at three depths (0-5 cm, 5-10 cm and 10-20 cm) from five crop rotations: I, conservationist agriculture (wheat-sorghum-soybean); II, mixed agriculture/livestock with pastures, without using winter or summer forages (wheat-sorghum-soybean-canola-pastures); III, winter agriculture in depth limited soils (wheat-canola-barley-late soybean); IV, mixed with annual forage (wheat-oat/Vicia-sunflower); V, intensive agriculture (wheat-barley-canola, with alternation of soybean or late soybean). One hundred twenty two isolates of Fusarium were obtained and identified as F. equiseti, F. merismoides, F. oxysporum, F. scirpi and F. solani. The most prevalent species was F. oxysporum, which was observed in all sequences and depths. The Tukey's test showed that the relative frequency of F. oxysporum under intensive agricultural management was higher than in mixed traditional ones. The first 5 cm of soil showed statistically significant differences (p=0.05) with respect to 5-10 cm and 10-20 cm depths. The ANOVA test for the relative frequency of the other species as F. equiseti, F. merismoides, F. scirpi and F. solani, did not show statistically significant differences (p<0.05). We did not find significant differences (p<0.05) in the effect of crop rotations and depth on Shannon, Simpson indexes and species richness. Therefore we conclude that the different sequences and the sampling depth did not affect the alpha diversity of Fusarium community in this system. (Author) 51 refs.

  18. Does governance play a role in the distribution of invasive alien species?

    Science.gov (United States)

    Evans, Thomas; Zu Ermgassen, Philine; Amano, Tatsuya; Peh, Kelvin S-H

    2018-02-01

    Invasive alien species (IAS) constitute a major threat to global biological diversity. In order to control their spread, a detailed understanding of the factors influencing their distribution is essential. Although international trade is regarded as a major force structuring spatial patterns of IAS, the role of other social factors remains unclear. Despite studies highlighting the importance of strong governance in slowing drivers of biodiversity loss such as logging, deforestation, and agricultural intensification, no study has yet analyzed its contribution to the issue of IAS. Using estimates of governance quality and comprehensive spatiotemporal IAS data, we performed multiple linear regressions to investigate the effect of governance quality upon the distribution of species listed under "100 of the worst" IAS in 38 Eurasian countries as defined by DASIE. Our model suggested that for countries with higher GDP, stronger governance was associated with a greater number of the worst IAS; in contrast, for the lowest GDP countries under analysis, stronger governance was associated with fewer of these IAS. We elucidate how the quality of governance within a country has implications for trade, tourism, transport, legislation, and economic development, all of which influence the spread of IAS. While our findings support the common assumption that strengthening governance benefits conservation interventions in countries of smaller economy, we find that this effect is not universal. Stronger governance alone cannot adequately address the problem of IAS, and targeted action is required in relatively high-GDP countries in order to stem the influx of IAS associated with high volumes of trade.

  19. Using maximum topology matching to explore differences in species distribution models

    Science.gov (United States)

    Poco, Jorge; Doraiswamy, Harish; Talbert, Marian; Morisette, Jeffrey; Silva, Claudio

    2015-01-01

    Species distribution models (SDM) are used to help understand what drives the distribution of various plant and animal species. These models are typically high dimensional scalar functions, where the dimensions of the domain correspond to predictor variables of the model algorithm. Understanding and exploring the differences between models help ecologists understand areas where their data or understanding of the system is incomplete and will help guide further investigation in these regions. These differences can also indicate an important source of model to model uncertainty. However, it is cumbersome and often impractical to perform this analysis using existing tools, which allows for manual exploration of the models usually as 1-dimensional curves. In this paper, we propose a topology-based framework to help ecologists explore the differences in various SDMs directly in the high dimensional domain. In order to accomplish this, we introduce the concept of maximum topology matching that computes a locality-aware correspondence between similar extrema of two scalar functions. The matching is then used to compute the similarity between two functions. We also design a visualization interface that allows ecologists to explore SDMs using their topological features and to study the differences between pairs of models found using maximum topological matching. We demonstrate the utility of the proposed framework through several use cases using different data sets and report the feedback obtained from ecologists.

  20. Fitting and comparing competing models of the species abundance distribution: assessment and prospect

    Directory of Open Access Journals (Sweden)

    Thomas J Matthews

    2014-06-01

    Full Text Available A species abundance distribution (SAD characterises patterns in the commonness and rarity of all species within an ecological community. As such, the SAD provides the theoretical foundation for a number of other biogeographical and macroecological patterns, such as the species–area relationship, as well as being an interesting pattern in its own right. While there has been resurgence in the study of SADs in the last decade, less focus has been placed on methodology in SAD research, and few attempts have been made to synthesise the vast array of methods which have been employed in SAD model evaluation. As such, our review has two aims. First, we provide a general overview of SADs, including descriptions of the commonly used distributions, plotting methods and issues with evaluating SAD models. Second, we review a number of recent advances in SAD model fitting and comparison. We conclude by providing a list of recommendations for fitting and evaluating SAD models. We argue that it is time for SAD studies to move away from many of the traditional methods available for fitting and evaluating models, such as sole reliance on the visual examination of plots, and embrace statistically rigorous techniques. In particular, we recommend the use of both goodness-of-fit tests and model-comparison analyses because each provides unique information which one can use to draw inferences.

  1. Species Richness, Community Organization, and Spatiotemporal Distribution of Earthworms in the Pineapple Agroecosystems of Tripura, India

    Directory of Open Access Journals (Sweden)

    Animesh Dey

    2016-01-01

    Full Text Available The impact that plant communities may have on underground faunal diversity is unclear. Therefore, understanding the links between plants and organisms is of major interest. Earthworm population dynamics were studied in the pineapple agroecosystems of Tripura to evaluate the impact of monoculture plantation on earthworm communities. A total of thirteen earthworm species belonging to four families and five genera were collected from different sampling sites. Application of sample-based rarefaction curve and nonparametric richness estimators reveal 90–95% completeness of sampling. Earthworm community of pineapple agroecosystems was dominated by endogeic earthworms and Drawida assamensis was the dominant species with respect to its density, biomass, and relative abundance. Vertical distribution of earthworms was greatly influenced by seasonal variations. Population density and biomass of earthworms peaked during monsoon and postmonsoon period, respectively. Overall density and biomass of earthworms were in increasing trend with an increase in plantation age and were highest in the 30–35-year-old plantation. Significant decrease in the Shannon diversity and evenness index and increase in Simpson’s dominance and spatial aggregation index with an increase in the age of pineapple plantation were recorded. Soil temperature and soil moisture were identified as the most potent regulators of earthworm distribution in the pineapple plantation.

  2. Evaluating Bayesian spatial methods for modelling species distributions with clumped and restricted occurrence data.

    Directory of Open Access Journals (Sweden)

    David W Redding

    Full Text Available Statistical approaches for inferring the spatial distribution of taxa (Species Distribution Models, SDMs commonly rely on available occurrence data, which is often clumped and geographically restricted. Although available SDM methods address some of these factors, they could be more directly and accurately modelled using a spatially-explicit approach. Software to fit models with spatial autocorrelation parameters in SDMs are now widely available, but whether such approaches for inferring SDMs aid predictions compared to other methodologies is unknown. Here, within a simulated environment using 1000 generated species' ranges, we compared the performance of two commonly used non-spatial SDM methods (Maximum Entropy Modelling, MAXENT and boosted regression trees, BRT, to a spatial Bayesian SDM method (fitted using R-INLA, when the underlying data exhibit varying combinations of clumping and geographic restriction. Finally, we tested how any recommended methodological settings designed to account for spatially non-random patterns in the data impact inference. Spatial Bayesian SDM method was the most consistently accurate method, being in the top 2 most accurate methods in 7 out of 8 data sampling scenarios. Within high-coverage sample datasets, all methods performed fairly similarly. When sampling points were randomly spread, BRT had a 1-3% greater accuracy over the other methods and when samples were clumped, the spatial Bayesian SDM method had a 4%-8% better AUC score. Alternatively, when sampling points were restricted to a small section of the true range all methods were on average 10-12% less accurate, with greater variation among the methods. Model inference under the recommended settings to account for autocorrelation was not impacted by clumping or restriction of data, except for the complexity of the spatial regression term in the spatial Bayesian model. Methods, such as those made available by R-INLA, can be successfully used to account

  3. Rapid upslope shifts in New Guinean birds illustrate strong distributional responses of tropical montane species to global warming

    Science.gov (United States)

    Freeman, Benjamin G.; Class Freeman, Alexandra M.

    2014-01-01

    Temperate-zone species have responded to warming temperatures by shifting their distributions poleward and upslope. Thermal tolerance data suggests that tropical species may respond to warming temperatures even more strongly than temperate-zone species, but this prediction has yet to be tested. We addressed this data gap by conducting resurveys to measure distributional responses to temperature increases in the elevational limits of the avifaunas of two geographically and faunally independent New Guinean mountains, Mt. Karimui and Karkar Island, 47 and 44 y after they were originally surveyed. Although species richness is roughly five times greater on mainland Mt. Karimui than oceanic Karkar Island, distributional shifts at both sites were similar: upslope shifts averaged 113 m (Mt. Karimui) and 152 m (Karkar Island) for upper limits and 95 m (Mt. Karimui) and 123 m (Karkar Island) for lower limits. We incorporated these results into a metaanalysis to compare distributional responses of tropical species with those of temperate-zone species, finding that average upslope shifts in tropical montane species match local temperature increases significantly more closely than in temperate-zone montane species. That tropical species appear to be strong responders has global conservation implications and provides empirical support to hitherto untested models that predict widespread extinctions in upper-elevation tropical endemics with small ranges. PMID:24550460

  4. Decoding Size Distribution Patterns in Marine and Transitional Water Phytoplankton: From Community to Species Level

    Science.gov (United States)

    Roselli, Leonilde; Basset, Alberto

    2015-01-01

    Understanding the mechanisms of phytoplankton community assembly is a fundamental issue of aquatic ecology. Here, we use field data from transitional (e.g. coastal lagoons) and coastal water environments to decode patterns of phytoplankton size distribution into organization and adaptive mechanisms. Transitional waters are characterized by higher resource availability and shallower well-mixed water column than coastal marine environments. Differences in physico-chemical regime between the two environments have been hypothesized to exert contrasting selective pressures on phytoplankton cell morphology (size and shape). We tested the hypothesis focusing on resource availability (nutrients and light) and mixed layer depth as ecological axes that define ecological niches of phytoplankton. We report fundamental differences in size distributions of marine and freshwater diatoms, with transitional water phytoplankton significantly smaller and with higher surface to volume ratio than marine species. Here, we hypothesize that mixing condition affecting size-dependent sinking may drive phytoplankton size and shape distributions. The interplay between shallow mixed layer depth and frequent and complete mixing of transitional waters may likely increase the competitive advantage of small phytoplankton limiting large cell fitness. The nutrient regime appears to explain the size distribution within both marine and transitional water environments, while it seem does not explain the pattern observed across the two environments. In addition, difference in light availability across the two environments appear do not explain the occurrence of asymmetric size distribution at each hierarchical level. We hypothesize that such competitive equilibria and adaptive strategies in resource exploitation may drive by organism’s behavior which exploring patch resources in transitional and marine phytoplankton communities. PMID:25974052

  5. Architecture and Distribution of Introns in Core Genes of Four Fusarium Species

    Directory of Open Access Journals (Sweden)

    Mmatshepho M. Phasha

    2017-11-01

    Full Text Available Removal of introns from transcribed RNA represents a crucial step during the production of mRNA in eukaryotes. Available whole-genome sequences and expressed sequence tags (ESTs have increased our knowledge of this process and revealed various commonalities among eukaryotes. However, certain aspects of intron structure and diversity are taxon-specific, which can complicate the accuracy of in silico gene prediction methods. Using core genes, we evaluated the distribution and architecture of Fusarium circinatum spliceosomal introns, and linked these characteristics to the accuracy of the predicted gene models of the genome of this fungus. We also evaluated intron distribution and architecture in F. verticillioides, F. oxysporum, and F. graminearum, and made comparisons with F. circinatum. Results indicated that F. circinatum and the three other Fusarium species have canonical 5′ and 3′ splice sites, but with subtle differences that are apparently not shared with those of other fungal genera. The polypyrimidine tract of Fusarium introns was also found to be highly divergent among species and genes. Furthermore, the conserved adenosine nucleoside required during the first step of splicing is contained within unique branch site motifs in certain Fusarium introns. Data generated here show that introns of F. circinatum, as well as F. verticillioides, F. oxysporum, and F. graminearum, are characterized by a number of unique features such as the CTHAH and ACCAT motifs of the branch site. Incorporation of such information into genome annotation software will undoubtedly improve the accuracy of gene prediction methods used for Fusarium species and related fungi.

  6. Epidemiology, species distribution and outcome of nosocomial Candida spp. bloodstream infection in Shanghai.

    Science.gov (United States)

    Yang, Zhi-Tao; Wu, Lin; Liu, Xiao-Ying; Zhou, Min; Li, Jie; Wu, Jia-Yin; Cai, Yong; Mao, En-Qiang; Chen, Er-Zhen; Lortholary, Olivier

    2014-05-06

    Yeasts, mostly Candida, are important causes of bloodstream infections (BSI), responsible for significant mortality and morbidity among hospitalized patients. The epidemiology and species distribution vary from different regions. The goals of this study were to report the current epidemiology of Candida BSI in a Shanghai Teaching Hospital and estimate the impact of appropriate antifungal therapy on the outcome. From January 2008 to December 2012, all consecutive patients who developed Candida BSI at Ruijin University Hospital were enrolled. Underlying diseases, clinical severity, species distribution, antifungal therapy and its impact on the outcome were analyzed. A total of 121 episodes of Candida BSI were identified, with an incidence of 0.32 episodes/1,000 admissions (0.21 in 2008 and 0.42 in 2012) The proportion of candidemia caused by non-albicans species (62.8%), including C. parapsilosis (19.8%), C. tropicalis (14.9%), C. glabrata (7.4%), C. guilliermondii (5.8%), C. sake (5.0%) was higher than that of candidemia caused by C. albicans (37.2%). The overall crude 28-day mortality was 28.1% and significantly reduced with appropriate empiric antifungal therapy administered within 5 days (P = 0.006). Advanced age (OR 1.04; P = 0.014), neutropenia risk factors for 28-day mortality, while appropriate empiric antifungal therapy (OR 0.369; P = 0.035) was protective against 28-day mortality. The epidemiology of candidemia in Shanghai differed from that observed in Western countries. Appropriate empiric antifungal therapy influenced the short-term survival.

  7. Nosocomial Bloodstream Infection Due to Candida spp. in China: Species Distribution, Clinical Features, and Outcomes.

    Science.gov (United States)

    Li, Ying; Du, Mingmei; Chen, Liang-An; Liu, Yunxi; Liang, Zhixin

    2016-08-01

    To investigate the distribution of Candida spp., predictors of mortality, and effects of therapeutic measures on outcomes of nosocomial bloodstream infection (BSI) due to Candida spp. This retrospective, population-based study enrolled adult patients with Candida nosocomial BSI from January 2010 to December 2014 in one tertiary care hospital. The demographics, comorbidities, species distribution, risk factors, and effects of antifungal treatment were assessed. In total, 190 episodes of Candida BSI were identified. The most prevalent species was C. albicans (38.9 %), followed by C. parapsilosis (23.2 %) and C. tropicalis (20.5 %). In vitro susceptibility testing showed that 88.9 % of Candida isolates were susceptible to fluconazole. The 30-day hospital mortality was 27.9 %, while the early mortality (within 7 days) was 16.3 %. In a multivariate regression analysis, the Acute Physiology and Chronic Health Evaluation II score [odds ratio (OR) 1.23; 95 % confidence interval (CI) 1.080-1.390; P = 0.002] and severe sepsis or septic shock (OR 15.35; 95 % CI 2.391-98.502; P = 0.004) were independently correlated with early mortality. Severe sepsis or septic shock (OR 24.75; 95 % CI 5.099-120.162; P risk factor for 30-day mortality, while proven catheter-related candidemia (OR 0.16; 95 % CI 0.031-0.810; P = 0.027) was a positive factor for 30-day mortality. Early central venous catheter removal and adequate antifungal treatment were closely related to decreased mortality in patients with primary candidemia. The proportion of candidemia caused by C. albicans was lower than that caused by non-albicans species. The severity of illness influenced early mortality, and the origin of the central venous catheter remarkably affected 30-day mortality.

  8. EVALUATING THE NOVEL METHODS ON SPECIES DISTRIBUTION MODELING IN COMPLEX FOREST

    Directory of Open Access Journals (Sweden)

    C. H. Tu

    2012-07-01

    Full Text Available The prediction of species distribution has become a focus in ecology. For predicting a result more effectively and accurately, some novel methods have been proposed recently, like support vector machine (SVM and maximum entropy (MAXENT. However, high complexity in the forest, like that in Taiwan, will make the modeling become even harder. In this study, we aim to explore which method is more applicable to species distribution modeling in the complex forest. Castanopsis carlesii (long-leaf chinkapin, LLC, growing widely in Taiwan, was chosen as the target species because its seeds are an important food source for animals. We overlaid the tree samples on the layers of altitude, slope, aspect, terrain position, and vegetation index derived from SOPT-5 images, and developed three models, MAXENT, SVM, and decision tree (DT, to predict the potential habitat of LLCs. We evaluated these models by two sets of independent samples in different site and the effect on the complexity of forest by changing the background sample size (BSZ. In the forest with low complex (small BSZ, the accuracies of SVM (kappa = 0.87 and DT (0.86 models were slightly higher than that of MAXENT (0.84. In the more complex situation (large BSZ, MAXENT kept high kappa value (0.85, whereas SVM (0.61 and DT (0.57 models dropped significantly due to limiting the habitat close to samples. Therefore, MAXENT model was more applicable to predict species’ potential habitat in the complex forest; whereas SVM and DT models would tend to underestimate the potential habitat of LLCs.

  9. Modeling the Spatial Distribution and Fruiting Pattern of a Key Tree Species in a Neotropical Forest: Methodology and Potential Applications

    National Research Council Canada - National Science Library

    Caillaud, Damien; Crofoot, Margaret C; Scarpino, Samuel V; Jansen, Patrick A; Garzon-Lopez, Carol X; Winkelhagen, Annemarie J. S; Bohlman, Stephanie A; Walsh, Peter D

    2010-01-01

    ... distributions of food resources. We illustrate our procedure by creating a detailed simulation model of fruit production patterns for Dipteryx oleifera, a keystone tree species, on Barro Colorado Island (BCI), Panama...

  10. Species distribution and antifungal susceptibility pattern of Candida causing oral candidiasis among hospitalized patients

    Directory of Open Access Journals (Sweden)

    Faseela Taivalap Shafi

    2015-01-01

    Full Text Available Background: Oral candidiasis is increasingly seen among hospitalized patients and is usually treated empirically. It can be the marker of systemic infection. Antifingal resistance is one of the emerging problems in candidiasis. Aim and Objectives: To study the distribution pattern of various Candida species among hospitalised patients with oral candidiasis, to detect the antifungal resistance among Candida and to assess the possible risk factors associated with those patients. Methods: Out of 300 patients screened, oral thrush material was collected from 36 patients having oral candidiasis. Candida spp. were isolated and identified. Antifungal susceptibility test was performed by disk diffusion method. Results: Candida albicans was the most frequently isolated species (64%. Highest resistance was seen with ketoconazole (18%. Except one C. tropicalis, all the isolates were sensitive to amphotericin B. All the patients were on broad spectrum antibiotic treatment. Diabetes mellitus was seen in 50 % of the patients. Other predisposing factors include tuberculosis, COPD, cancer and steroid treatment. Conclusion: Eventhough there is progressive shift from a predominance of C. albicans to non-albicans Candida species in candidiasis, C. albicans remains as the most important pathogen in oral candidiasis. Since azole resistance is increasing, accurate identification of Candida spp. and antifungal susceptibility testing is crucial for patient management and for facilitating hospital control measures.

  11. Temporospatial distribution of Culicoides species and Culicoides imicola in northern Jordan

    Directory of Open Access Journals (Sweden)

    Rami M. Mukbel

    2016-08-01

    Full Text Available The aim of this study was to estimate geographical distribution of Culicoides species and Culicoides imicola in northern governorates of Jordan. The study was conducted by placing light traps in four climatically different geographical locations during 2011. Suitability maps were created by layering and compiling climatic parameters into the GIS data to highlight locations and time suitable for growth of C. imicola. Collected insect samples were assorted by morphology to identify Culicoides species. Molecular analysis was used to identify Culicoides spp. and C. imicola. In total, 25,196 insects were trapped of which 3491 (12.7% were morphologically identified as Culicoides spp. The highest counts Culicoides spp. were recorded in Deir Alla (47%, Banikenaneh (31% and Al-Shouneh (21% respectively. The peak activity was recorded during August through October. Morphological identification failed to identify Culicoides species in 4 locations while polymerase chain reaction analysis identified Culicoides spp. in all locations except Al-mafraq. C. imicola could only be identified in Deir Alla, Bani-kenaneh and Al-Shouneh. There was no evidence of viral genome of epizootic hemorrhagic disease virus, blue tongue virus and bovine ephemeral fever virus in the trapped midges.

  12. Climatic zoning of chia (Salvia hispanica L. in Chile using a species distribution model

    Directory of Open Access Journals (Sweden)

    Daniela Cortés

    2017-11-01

    Full Text Available Salvia hispanica L., known as chia, is a plant species originally from tropical and subtropical Mesoamerica. It is economically important because its seeds produce omega-3, thus its demand has increased in Chile and internationally. As there is no commercial production in Chile, we investigated the places in the country where this species could be cultivated in order to satisfy at the least the national demand. The aim of the study was to quantify the main climatic requirements of chia and to produce a climatic aptitude map for chia cultivation in Chile. The methodology was based on the Maxent species distribution model. We used 78 georeferenced data points where chia is grown throughout the world, mostly from the GBIF database, along with raster climatic layers from the Worldclim project. We estimated the performance curves of annual precipitation and temperature along with their respective optimal and critical values, in analogy with the Ecocrop method. The maps used two scenarios for crops in different conditions, with and without irrigation. The results indicated that the intermediate depression and coastal edge of mainly the Arica y Parinacota, Tarapacá, Antofagasta and Atacama regions have optimum conditions for irrigated crops, but it would be impossible in rainfed conditions. We conclude that chia’s cultivation niche is reduced due to its tropical climate requirements; however, it can be cultivated under irrigation in northern Chile.

  13. Distribution of Pseudomonas Species in a Dairy Plant Affected by Occasional Blue Discoloration.

    Science.gov (United States)

    Chiesa, Francesco; Lomonaco, Sara; Nucera, Daniele; Garoglio, Davide; Dalmasso, Alessandra; Civera, Tiziana

    2014-12-09

    During 2010 many cases of discoloration in mozzarella, popularly termed as blue mozzarella, have been reported to the attention of public opinion. Causes of the alteration were bacteria belonging to the genus Pseudomonas. The strong media impact of such cases has created confusion, not only among consumers, but also among experts. In order to help improving the knowledge on microbial ecology of this microorganism a study has been set up with the collaboration of a medium-sized dairy plant producing fresh mozzarella cheese, with occasional blue discoloration, conducting surveys and sampling in the pre-operational, operational and post-operational process phase, milk before and after pasteurization, water (n=12), environmental surfaces (n=22) and the air (n=27). A shelf life test was conducted on finished products stored at different temperatures (4-8°C). Among the isolates obtained from the microbiological analysis of the samples, 60 were subjected to biomolecular tests in order to confirm the belonging to Pseudomonas genus and to get an identification at species level by the amplification and sequencing of the gyrB gene. The results of microbiological tests demonstrated the presence of microorganisms belonging to the genus Pseudomonas along the entire production lane; molecular tests showed 7 different species among the 40 isolates identified. One particular species (Pseudomonas koreensis) was isolated from blue discolored mozzarella cheese and was indicated as the most relevant for the production plant, both for the distribution along the processing chain and for the consequences on the finished product.

  14. Contrasting genetic structure in two co-distributed species of old world fruit bat.

    Directory of Open Access Journals (Sweden)

    Jinping Chen

    Full Text Available The fulvous fruit bat (Rousettus leschenaulti and the greater short-nosed fruit bat (Cynopterus sphinx are two abundant and widely co-distributed Old World fruit bats in Southeast and East Asia. The former species forms large colonies in caves while the latter roots in small groups in trees. To test whether these differences in social organization and roosting ecology are associated with contrasting patterns of gene flow, we used mtDNA and nuclear loci to characterize population genetic subdivision and phylogeographic histories in both species sampled from China, Vietnam and India. Our analyses from R. leschenaulti using both types of marker revealed little evidence of genetic structure across the study region. On the other hand, C. sphinx showed significant genetic mtDNA differentiation between the samples from India compared with China and Vietnam, as well as greater structuring of microsatellite genotypes within China. Demographic analyses indicated signatures of past rapid population expansion in both taxa, with more recent demographic growth in C. sphinx. Therefore, the relative genetic homogeneity in R. leschenaulti is unlikely to reflect past events. Instead we suggest that the absence of substructure in R. leschenaulti is a consequence of higher levels of gene flow among colonies, and that greater vagility in this species is an adaptation associated with cave roosting.

  15. Geographic distribution and host plants of Raoiella indica and associated mite species in northern Venezuela.

    Science.gov (United States)

    Vásquez, Carlos; de Moraes, Gilberto J

    2013-05-01

    The red palm mite (RPM), Raoiella indica Hirst (Acari: Tenuipalpidae), is an invasive pest in the New World, where it is currently considered a serious threat to coconut and banana crops. It was first reported from northern Venezuela in 2007. To determine its current distribution in this country, surveys were carried out from October 2008 to April 2010 on coconut (Cocos nucifera L.), banana (Musa spp.), ornamental plants and weeds in northern Venezuela. Higher population levels of RPM were registered on commercial coconut farms in Falcón and Sucre states but also on other plant species naturally growing along the coastal line in Anzoategui, Aragua, Carabobo, Monagas and Nueva Esparta states. Out of 34 botanical species evaluated, all RPM stages were observed only on eight arecaceous, one musaceous and one streliziaceous species, indicating that the pest developed and reproduced only on these plants. Mite specimens found on weeds were considered spurious events, as immature stages of the pest were never found on these. Amblyseius largoensis (Muma) (Acari: Phytoseiidae) was the most frequent predatory mite associated with RPM in all sampling sites. The results indicate that RPM has spread to extensive areas of northern Venezuela since its initial detection in Güiria, Sucre state. Considering the report of this pest mite in northern Brazil in the late 2009, additional samplings in southern Venezuela should be carried out, to evaluate the possible presence of RPM also in that region.

  16. World-wide species distributions in the family Kyphosidae (Teleostei: Perciformes).

    Science.gov (United States)

    Knudsen, Steen Wilhelm; Clements, Kendall D

    2016-08-01

    Sea chubs of the family Kyphosidae are major consumers of macroalgae on both temperate and tropical reefs, where they can comprise a significant proportion of fish biomass. However, the relationships and taxonomic status of sea chubs (including the junior synonyms Hermosilla, Kyphosus, Neoscorpis and Sectator) worldwide have long been problematical due to perceived lack of character differentiation, complicating ecological assessment. More recently, the situation has been further complicated by publication of conflicting taxonomic treatments. Here, we resolve the relationships, taxonomy and distribution of all known species of sea chubs through a combined analysis of partial fragments from mitochondrial markers (12s, 16s, cytb, tRNA -Pro, -Phe, -Thr and -Val) and three nuclear markers (rag1, rag2, tmo4c4). These new results provide independent evidence for the presence of several junior synonyms among Atlantic and Indo-Pacific taxa, demonstrating that several sea chub species are more widespread than previously thought. In particular, our results can reject the hypothesis of endemic species in the Atlantic Ocean. At a higher taxonomic level, our results shed light on the relationships between Girellidae, Kuhliidae, Kyphosidae, Microcanthidae, Oplegnathidae and Scorpididae, with Scorpididae resolved as the sister group to Kyphosidae. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Molluscan species of minor commercial interest in Hellenic seas: Distribution, exploitation and conservation status

    Directory of Open Access Journals (Sweden)

    S. KATSANEVAKIS

    2008-05-01

    Full Text Available Recognising the need for data gathering at taxon level besides the taxa of commercial interest and those listed as endangered in the Protocol of the Barcelona Convention, but still exploited by Man, the present study attempts to gather and review the available scientific information on molluscs of minor commercial importance in order to assist in the adequate management and protection of their populations. Forty one species (18 gastropods, 13 bivalves, and 10 cephalopods of minor commercial interest are treated in the present work with details on their biogeographic distribution, exploitation and conservation status in Hellas. Apart from a few species (e.g., Pinna nobilis, Lithophaga lithophaga, Donacilla cornea, and these only at a local scale, there is no population assessment in Hellenic seas. The existing legislation for eleven of these species is not enforced in practice, and seems insufficient to guarantee their conservation. It is suggested that targeted collection data, networked nationally and internationally, should be promoted so this invaluable source of biodiversity information can be accessed for conservation and planning purposes.

  18. Microbial Distribution and Abundance in the Digestive System of Five Shipworm Species (Bivalvia: Teredinidae)

    Science.gov (United States)

    Betcher, Meghan A.; Fung, Jennifer M.; Han, Andrew W.; O’Connor, Roberta; Seronay, Romell; Concepcion, Gisela P.; Distel, Daniel L.; Haygood, Margo G.

    2012-01-01

    Marine bivalves of the family Teredinidae (shipworms) are voracious consumers of wood in marine environments. In several shipworm species, dense communities of intracellular bacterial endosymbionts have been observed within specialized cells (bacteriocytes) of the gills (ctenidia). These bacteria are proposed to contribute to digestion of wood by the host. While the microbes of shipworm gills have been studied extensively in several species, the abundance and distribution of microbes in the digestive system have not been adequately addressed. Here we use Fluorescence In-Situ Hybridization (FISH) and laser scanning confocal microscopy with 16S rRNA directed oligonucleotide probes targeting all domains, domains Bacteria and Archaea, and other taxonomic groups to examine the digestive microbiota of 17 specimens from 5 shipworm species (Bankia setacea, Lyrodus pedicellatus, Lyrodus massa, Lyrodus sp. and Teredo aff. triangularis). These data reveal that the caecum, a large sac-like appendage of the stomach that typically contains large quantities of wood particles and is considered the primary site of wood digestion, harbors only very sparse microbial populations. However, a significant number of bacterial cells were observed in fecal pellets within the intestines. These results suggest that due to low abundance, bacteria in the caecum may contribute little to lignocellulose degradation. In contrast, the comparatively high population density of bacteria in the intestine suggests a possible role for intestinal bacteria in the degradation of lignocellulose. PMID:23028923

  19. Assessment of substratum effect on the distribution of two invasive Caulerpa (Chlorophyta) species

    Science.gov (United States)

    Infantes, Eduardo; Terrados, Jorge; Orfila, Alejandro

    2011-02-01

    Two-year monitoring of the invasive marine Chlorophyta Caulerpa taxifolia and Caulerpa racemosa var. cylindracea shows the great influence of substratum on their spatial distribution. The cover of C. taxifolia and C. racemosa was measured in shallow (<8 m) areas indicating that these species are more abundant in rocks with photophilic algae and in the dead matte of the seagrass Posidonia oceanica than in sand or inside the P. oceanica meadow. A short-term experiment comparing the persistence of C. taxifolia and C. racemosa planted either in a model of dead matte of P. oceanica or in sand shows that the persistence of these species was higher in the dead matte model than in sand. Correlative evidence suggests that C. taxifolia and C. racemosa tolerate near-bottom orbital velocities below 15 cm s -1 and that C. taxifolia cover declines at velocities above that value. These results contribute to understand the process of invasion of these Caulerpa species predicting which substrata would be more susceptible to be invaded and to the adoption of appropriate management strategies.

  20. Distribution and abundance of MAAs in 33 species of microalgae across 13 classes.

    Science.gov (United States)

    Llewellyn, Carole Anne; Airs, Ruth Louise

    2010-04-16

    We provide a direct comparison of the distribution and abundance of mycosporine-like amino acids (MAAs) in a diverse range of microalgal cultures (33 species across 13 classes) grown without supplementary ultraviolet radiation (UV). We compare the MAAs in cultures with those present in characterised natural phytoplankton populations from the English Channel. We detected 25 UV absorbing compounds including at least two with multiple absorption maxima. We used LC-MS to provide chemical characterisation of the six most commonly occurring MAAs, namely, palythene, palythine, mycosporine-glycine, palythenic acid, porphyra-334 and shinorine. MAAs were abundant (up to 7 pg MAA cell(-1)) in 10 species, with more minor and often unknown MAAs in a further 11 cultures. Shinorine was the most frequently occurring and abundant MAA (up to 6.5 pg cell(-1)) and was present in all but two of the MAA-containing species. The study provides further insight into the diversity and abundance of MAAs important from an ecological perspective and as potential source of natural alternatives to synthetic sunscreens.

  1. Distribution and Abundance of MAAs in 33 Species of Microalgae across 13 Classes

    Directory of Open Access Journals (Sweden)

    Carole Anne Llewellyn

    2010-04-01

    Full Text Available We provide a direct comparison of the distribution and abundance of mycosporine-like amino acids (MAAs in a diverse range of microalgal cultures (33 species across 13 classes grown without supplementary ultraviolet radiation (UV. We compare the MAAs in cultures with those present in characterised natural phytoplankton populations from the English Channel. We detected 25 UV absorbing compounds including at least two with multiple absorption maxima. We used LC-MS to provide chemical characterisation of the six most commonly occurring MAAs, namely, palythene, palythine, mycosporine-glycine, palythenic acid, porphyra-334 and shinorine. MAAs were abundant (up to 7 pg MAA cell−1in 10 species, with more minor and often unknown MAAs in a further 11 cultures. Shinorine was the most frequently occurring and abundant MAA (up to 6.5 pg cell−1 and was present in all but two of the MAA-containing species. The study provides further insight into the diversity and abundance of MAAs important from an ecological perspective and as potential source of natural alternatives to synthetic sunscreens.

  2. Statics with MATLAB

    CERN Document Server

    Marghitu, Dan B; Madsen, Nels H

    2013-01-01

    Engineering mechanics involves the development of mathematical models of the physical world. Statics addresses the forces acting on and in mechanical objects and systems. Statics with MATLAB®  develops an understanding of the mechanical behavior of complex engineering structures and components using MATLAB®  to execute numerical calculations and to facilitate analytical calculations.   MATLAB® is presented and introduced as a highly convenient tool to solve problems for theory and applications in statics. Included are example problems to demonstrate the MATLAB® syntax and to also introduce specific functions dealing with statics. These explanations are reinforced through figures generated with MATLAB® and the extra material available online which includes the special functions described. This detailed introduction and application of MATLAB® to the field of statics makes Statics with MATLAB® a useful tool for instruction as well as self study,  highlighting the use of symbolic MATLAB® for both theo...

  3. Climatic associations of British species distributions show good transferability in time but low predictive accuracy for range change.

    Directory of Open Access Journals (Sweden)

    Giovanni Rapacciuolo

    Full Text Available Conservation planners often wish to predict how species distributions will change in response to environmental changes. Species distribution models (SDMs are the primary tool for making such predictions. Many methods are widely used; however, they all make simplifying assumptions, and predictions can therefore be subject to high uncertainty. With global change well underway, field records of observed range shifts are increasingly being used for testing SDM transferability. We used an unprecedented distribution dataset documenting recent range changes of British vascular plants, birds, and butterflies to test whether correlative SDMs based on climate change provide useful approximations of potential distribution shifts. We modelled past species distributions from climate using nine single techniques and a consensus approach, and projected the geographical extent of these models to a more recent time period based on climate change; we then compared model predictions with recent observed distributions in order to estimate the temporal transferability and prediction accuracy of our models. We also evaluated the relative effect of methodological and taxonomic variation on the performance of SDMs. Models showed good transferability in time when assessed using widespread metrics of accuracy. However, models had low accuracy to predict where occupancy status changed between time periods, especially for declining species. Model performance varied greatly among species within major taxa, but there was also considerable variation among modelling frameworks. Past climatic associations of British species distributions retain a high explanatory power when transferred to recent time--due to their accuracy to predict large areas retained by species--but fail to capture relevant predictors of change. We strongly emphasize the need for caution when using SDMs to predict shifts in species distributions: high explanatory power on temporally-independent records

  4. Distribution of motor unit potential velocities in the biceps brachii muscle of sprinters and endurance athletes during short static contractions at low force level

    NARCIS (Netherlands)

    Klaver-Krol, Ewa G.; Henriquez, Nizare R.; Oosterloo, Sebe J.; Klaver, Peter; Kuipers, Harm; Zwarts, Machiel J.

    2010-01-01

    In surface electromyography (sEMG), the distribution of motor unit potential (MUP) velocities has been shown to reflect the proportion of faster and slower propagating MUPs. This study investigated whether the distribution of MUP velocities could distinguish between sprinters and endurance athletes

  5. Species Diversity and Distribution of Amphibians and Reptiles in Nature Park "Sinite Kamani" in Stara Planina Mt. (Bulgaria

    Directory of Open Access Journals (Sweden)

    Stanimira R. Deleva

    2014-12-01

    Full Text Available The current study presents briefly the species composition and distribution of the amphibians and reptiles in the Nature Park "Sinite Kamani" in Stara Planina Mnt. Bulgaria, based on a 2×2 km UTM grid. Between 2012 and 2014, we identified total 20 species (7 amphibians and 13 reptiles. We documented three new amphibian species for the region (Hyla arborea, Rana dalmatina and Rana graeca, which is discovered for the area for the first time and three species of reptiles (Testudo hermanni, Ablepharus kitaibelii and Lacerta trilienata. The contemporary conservation status for each species is presented and conservation threats and problems, specific for the park are discussed.

  6. Static electromagnetic frequency changers

    CERN Document Server

    Rozhanskii, L L

    1963-01-01

    Static Electromagnetic Frequency Changers is about the theory, design, construction, and applications of static electromagnetic frequency changers, devices that used for multiplication or division of alternating current frequency. It is originally published in the Russian language. This book is organized into five chapters. The first three chapters introduce the readers to the principles of operation, the construction, and the potential applications of static electromagnetic frequency changers and to the principles of their design. The two concluding chapters use some hitherto unpublished work

  7. Effects of climate change on three species of Cupido (Lepidoptera, Lycaenidae) with different biogeographic distribution in Andalusia, southern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Obregon, R.; Fernandez Haeger, J.; Jordano, D.

    2016-07-01

    Knowledge of the spatial distribution of rare or endangered species is of key importance to assess conservation status at different geographic scales and to develop conservation and recovery programs. In this paper we review and update the distribution of three species of Lycaenid butterflies in Andalusia (southern Spain): Cupido carswelli, C. lorquinii, and C. osiris. Cupido carswelli is endemic in south east Spain and is considered a vulnerable species in the Red Book of Invertebrates of Andalusia. Cupido lorquinii is an Iberian–Maghrebian endemism, found in the southern half of the Iberian peninsula. Cupido osiris, widely distributed in Europe and Central Asia, has its southern limit of distribution in Andalusia. We modeled the potential current distribution of these species in Andalusia, using Maxent. Their potential distribution was mainly conditioned by the presence of their host plants and, to a lesser extent, by climatic variables: rainfall during the warmest and coldest quarters of the year and annual mean temperature. AUC test values, sensitivity, and specificity for the three models were high, confirming the accuracy of the models and their high predictive values. We also modeled the potential future distributions of the three species under the climate change scenario A2a. Our results predict a significant reduction in the potential distribution for C. lorquinii —which has a wider distribution in Andalusia than the other two species— and for the more localized species, C. osiris and C. carswelli. This expected decline in the south of the Iberian peninsula highlights the pressing need to design and implement specific conservation plans for these species. (Author)

  8. Effects of climate change on three species of Cupido (Lepidoptera, Lycaenidae with different biogeographic distribution in Andalusia, southern Spain

    Directory of Open Access Journals (Sweden)

    Obregón, R.

    2016-03-01

    Full Text Available Knowledge of the spatial distribution of rare or endangered species is of key importance to assess conservation status at different geographic scales and to develop conservation and recovery programs. In this paper we review and update the distribution of three species of Lycaenid butterflies in Andalusia (southern Spain: Cupido carswelli, C. lorquinii, and C. osiris. Cupido carswelli is endemic in south east Spain and is considered a vulnerable species in the Red Book of Invertebrates of Andalusia. Cupido lorquinii is an Iberian–Maghrebian endemism, found in the southern half of the Iberian peninsula. Cupido osiris, widely distributed in Europe and Central Asia, has its southern limit of distribution in Andalusia. We modeled the potential current distribution of these species in Andalusia, using Maxent. Their potential distribution was mainly conditioned by the presence of their host plants and, to a lesser extent, by climatic variables: rainfall during the warmest and coldest quarters of the year and annual mean temperature. AUC test values, sensitivity, and specificity for the three models were high, confirming the accuracy of the models and their high predictive values. We also modeled the potential future distributions of the three species under the climate change scenario A2a. Our results predict a significant reduction in the potential distribution for C. lorquinii —which has a wider distribution in Andalusia than the other two species— and for the more localized species, C. osiris and C. carswelli. This expected decline in the south of the Iberian peninsula highlights the pressing need to design and implement specific conservation plans for these species.

  9. Predicting the potential distribution of invasive exotic species using GIS and information-theoretic approaches: A case of ragweed (Ambrosia artemisiifolia L.) distribution in China

    Science.gov (United States)

    Hao, Chen; LiJun, Chen; Albright, Thomas P.

    2007-01-01

    Invasive exotic species pose a growing threat to the economy, public health, and ecological integrity of nations worldwide. Explaining and predicting the spatial distribution of invasive exotic species is of great importance to prevention and early warning efforts. We are investigating the potential distribution of invasive exotic species, the environmental factors that influence these distributions, and the ability to predict them using statistical and information-theoretic approaches. For some species, detailed presence/absence occurrence data are available, allowing the use of a variety of standard statistical techniques. However, for most species, absence data are not available. Presented with the challenge of developing a model based on presence-only information, we developed an improved logistic regression approach using Information Theory and Frequency Statistics to produce a relative suitability map. This paper generated a variety of distributions of ragweed (Ambrosia artemisiifolia L.) from logistic regression models applied to herbarium specimen location data and a suite of GIS layers including climatic, topographic, and land cover information. Our logistic regression model was based on Akaike's Information Criterion (AIC) from a suite of ecologically reasonable predictor variables. Based on the results we provided a new Frequency Statistical method to compartmentalize habitat-suitability in the native range. Finally, we used the model and the compartmentalized criterion developed in native ranges to "project" a potential distribution onto the exotic ranges to build habitat-suitability maps. ?? Science in China Press 2007.

  10. MODELING SPATIAL DISTRIBUTION OF A RARE AND ENDANGERED PLANT SPECIES (Brainea insignis IN CENTRAL TAIWAN

    Directory of Open Access Journals (Sweden)

    W.-C. Wang

    2012-07-01

    Full Text Available With an increase in the rate of species extinction, we should choose right methods that are sustainable on the basis of appropriate science and human needs to conserve ecosystems and rare species. Species distribution modeling (SDM uses 3S technology and statistics and becomes increasingly important in ecology. Brainea insignis (cycad-fern, CF has been categorized a rare, endangered plant species, and thus was chosen as a target for the study. Five sampling schemes were created with different combinations of CF samples collected from three sites in Huisun forest station and one site, 10 km farther north from Huisun. Four models, MAXENT, GARP, generalized linear models (GLM, and discriminant analysis (DA, were developed based on topographic variables, and were evaluated by five sampling schemes. The accuracy of MAXENT was the highest, followed by GLM and GARP, and DA was the lowest. More importantly, they can identify the potential habitat less than 10% of the study area in the first round of SDM, thereby prioritizing either the field-survey area where microclimatic, edaphic or biotic data can be collected for refining predictions of potential habitat in the later rounds of SDM or search areas for new population discovery. However, it was shown unlikely to extend spatial patterns of CFs from one area to another with a big separation or to a larger area by predictive models merely based on topographic variables. Follow-up studies will attempt to incorporate proxy indicators that can be extracted from hyperspectral images or LIDAR DEM and substitute for direct parameters to make predictive models applicable on a broader scale.

  11. A relationship between carotenoid accumulation and the distribution of species of the fungus Neurospora in Spain.

    Science.gov (United States)

    Luque, Eva M; Gutiérrez, Gabriel; Navarro-Sampedro, Laura; Olmedo, María; Rodríguez-Romero, Julio; Ruger-Herreros, Carmen; Tagua, Víctor G; Corrochano, Luis M

    2012-01-01

    The ascomycete fungus Neurospora is present in many parts of the world, in particular in tropical and subtropical areas, where it is found growing on recently burned vegetation. We have sampled the Neurospora population across Spain. The sampling sites were located in the region of Galicia (northwestern corner of the Iberian peninsula), the province of Cáceres, the city of Seville, and the two major islands of the Canary Islands archipelago (Tenerife and Gran Canaria, west coast of Africa). The sites covered a latitude interval between 27.88° and 42.74°. We have identified wild-type strains of N. discreta, N. tetrasperma, N. crassa, and N. sitophila and the frequency of each species varied from site to site. It has been shown that after exposure to light Neurospora accumulates the orange carotenoid neurosporaxanthin, presumably for protection from UV radiation. We have found that each Neurospora species accumulates a different amount of carotenoids after exposure to light, but these differences did not correlate with the expression of the carotenogenic genes al-1 or al-2. The accumulation of carotenoids in Neurospora shows a correlation with latitude, as Neurospora strains isolated from lower latitudes accumulate more carotenoids than strains isolated from higher latitudes. Since regions of low latitude receive high UV irradiation we propose that the increased carotenoid accumulation may protect Neurospora from high UV exposure. In support of this hypothesis, we have found that N. crassa, the species that accumulates more carotenoids, is more resistant to UV radiation than N. discreta or N. tetrasperma. The photoprotection provided by carotenoids and the capability to accumulate different amounts of carotenoids may be responsible, at least in part, for the distribution of Neurospora species that we have observed across a range of latitudes.

  12. A relationship between carotenoid accumulation and the distribution of species of the fungus Neurospora in Spain.

    Directory of Open Access Journals (Sweden)

    Eva M Luque

    Full Text Available The ascomycete fungus Neurospora is present in many parts of the world, in particular in tropical and subtropical areas, where it is found growing on recently burned vegetation. We have sampled the Neurospora population across Spain. The sampling sites were located in the region of Galicia (northwestern corner of the Iberian peninsula, the province of Cáceres, the city of Seville, and the two major islands of the Canary Islands archipelago (Tenerife and Gran Canaria, west coast of Africa. The sites covered a latitude interval between 27.88° and 42.74°. We have identified wild-type strains of N. discreta, N. tetrasperma, N. crassa, and N. sitophila and the frequency of each species varied from site to site. It has been shown that after exposure to light Neurospora accumulates the orange carotenoid neurosporaxanthin, presumably for protection from UV radiation. We have found that each Neurospora species accumulates a different amount of carotenoids after exposure to light, but these differences did not correlate with the expression of the carotenogenic genes al-1 or al-2. The accumulation of carotenoids in Neurospora shows a correlation with latitude, as Neurospora strains isolated from lower latitudes accumulate more carotenoids than strains isolated from higher latitudes. Since regions of low latitude receive high UV irradiation we propose that the increased carotenoid accumulation may protect Neurospora from high UV exposure. In support of this hypothesis, we have found that N. crassa, the species that accumulates more carotenoids, is more resistant to UV radiation than N. discreta or N. tetrasperma. The photoprotection provided by carotenoids and the capability to accumulate different amounts of carotenoids may be responsible, at least in part, for the distribution of Neurospora species that we have observed across a range of latitudes.

  13. Faunal breaks and species composition of Indo-Pacific corals: the role of plate tectonics, environment and habitat distribution.

    Science.gov (United States)

    Keith, S A; Baird, A H; Hughes, T P; Madin, J S; Connolly, S R

    2013-07-22

    Species richness gradients are ubiquitous in nature, but the mechanisms that generate and maintain these patterns at macroecological scales remain unresolved. We use a new approach that focuses on overlapping geographical ranges of species to reveal that Indo-Pacific corals are assembled within 11 distinct faunal provinces. Province limits are characterized by co-occurrence of multiple species range boundaries. Unexpectedly, these faunal breaks are poorly predicted by contemporary environmental conditions and the present-day distribution of habitat. Instead, faunal breaks show striking concordance with geological features (tectonic plates and mantle plume tracks). The depth range over which a species occurs, its larval development rate and genus age are important determinants of the likelihood that species will straddle faunal breaks. Our findings indicate that historical processes, habitat heterogeneity and species colonization ability account for more of the present-day biogeographical patterns of corals than explanations based on the contemporary distribution of reefs or environmental conditions.

  14. Diel variation in feeding and vertical distribution of ten co- occurring fish species: consequences for resource partitioning

    NARCIS (Netherlands)

    Piet, G.J.; Guruge, W.A.H.P.

    1997-01-01

    The diel variations in feeding behaviour and vertical distribution were determined for ten species of a tropical fish community in a shallow SE Sri Lankan reservoir. The fish community consisted of two introduced exotic tilapias and eight indigenous riverine species including five cyprinids, one

  15. Contribution of climate, soil, and MODIS predictors when modeling forest inventory invasive species distribution using forest inventory data

    Science.gov (United States)

    Dumitru Salajanu; Dennis Jacobs

    2010-01-01

    Forest inventory and analysis data are used to monitor the presence and extent of certain non-native invasive species. Effective control of its spread requires quality spatial distribution information. There is no clear consensus why some ecosystems are more favorable to non-native species. The objective of this study is to evaluate the reelative contribution of geo-...

  16. Establishing species distributions in large tropical plant genera: insights from twelve new Thai records of Oberonia (Orchidaceae)

    NARCIS (Netherlands)

    Bunpha, K.; Pedersen, H.Æ.; Sridith, K.

    2013-01-01

    Establishing species distributions is particularly challenging in large tropical genera of inconspicuous plants. One such genus is Oberonia (Orchidaceae) which we are currently revising for Thailand. When encountering material of a putatively new species, great care has been taken to make a wide

  17. Species distributions in response to individual soil nutrients and seasonal drought across a community of tropical trees

    Science.gov (United States)

    Condit, Richard; Engelbrecht, Bettina M. J.; Pino, Delicia; Pérez, Rolando; Turner, Benjamin L.

    2013-01-01

    Tropical forest vegetation is shaped by climate and by soil, but understanding how the distributions of individual tree species respond to specific resources has been hindered by high diversity and consequent rarity. To study species over an entire community, we surveyed trees and measured soil chemistry across climatic and geological gradients in central Panama and then used a unique hierarchical model of species occurrence as a function of rainfall and soil chemistry to circumvent analytical difficulties posed by rare species. The results are a quantitative assessment of the responses of 550 tree species to eight environmental factors, providing a measure of the importance of each factor across the entire tree community. Dry-season intensity and soil phosphorus were the strongest predictors, each affecting the distribution of more than half of the species. Although we anticipated clear-cut responses to dry-season intensity, the finding that many species have pronounced associations with either high or low phosphorus reveals a previously unquantified role for this nutrient in limiting tropical tree distributions. The results provide the data necessary for understanding distributional limits of tree species and predicting future changes in forest composition. PMID:23440213

  18. The species sensivity distribution approach compared to a micrososm study: A case study with the fungicide fluazinam

    NARCIS (Netherlands)

    Wijngaarden, van R.P.A.; Arts, G.H.P.; Belgers, J.D.M.; Boonstra, H.; Roessink, I.; Schroer, A.F.W.; Brock, T.C.M.

    2010-01-01

    We assessed the sensitivity of freshwater organisms (invertebrates and algae) to the fungicide Shirlan® (active ingredient fluazinam) in single-species laboratory tests and in microcosms. Species sensitivity distribution (SSD) curves were constructed by means of acute toxicity data for 14

  19. Distribution patterns of macrofaunal species diversity in subtidal soft sediments: biodiversity-productivity relationships from the MacroBen database

    NARCIS (Netherlands)

    Escaravage, V.L.; Herman, P.M.J.; Merckx, B.; Bodarska-Kowalczuk, M.W.; Amouroux, J.M.; Degraer, S.; Grémare, A.; Heip, C.H.R.; Hummel, H.; Karakassis, I.; Labrune, C.; Willems, W.

    2009-01-01

    We analyzed patterns of species diversity in a compiled data set covering the European coast (from Norway to Crete) that was made available in the framework of the MarBEF European Network of Excellence. The focus was on the distribution patterns of species diversity over large areas across Europe.

  20. A new, widely distributed species of the Exocelina ekari-group from West Papua (Coleoptera, Dytiscidae, Copelatinae).

    Science.gov (United States)

    Shaverdo, Helena; Panjaitan, Rawati; Balke, Michael

    2016-01-01

    Exocelina manokwariensis sp. n. from West Papua is placed into the Exocelina ekari-group based on the structure of its male genitalia. The new species is described, including its three subspecies, from the mainland of West Papua, Waigeo Island, Batanta and Salawati Islands, and Bomberai peninsula. An identification key to the subspecies as well as data on species distribution are provided.

  1. Unusual distribution of Burkholderia cepacia complex species in Danish cystic fibrosis clinics may stem from restricted transmission between patients

    DEFF Research Database (Denmark)

    Nørskov-Lauritsen, Niels; Johansen, Helle Krogh; Fenger, Mette G

    2010-01-01

    Forty-four of 48 Burkholderia cepacia complex strains cultured from Danish cystic fibrosis patients were Burkholderia multivorans, a distribution of species that has not been reported before. Although cases of cross infections were demonstrated, no major epidemic clone was found. The species...

  2. Diagnostic description and geographic distribution of four new cryptic species of the blue-spotted maskray species complex (Myliobatoidei: Dasyatidae; Neotrygon spp.) based on DNA sequences

    Science.gov (United States)

    Borsa, Philippe; Arlyza, Irma S.; Hoareau, Thierry B.; Shen, Kang-Ning

    2017-08-01

    Nine morphologically similar but genetically distinct lineages in the blue-spotted maskray species complex, previously Neotrygon kuhlii (Müller and Henle) qualify as cryptic species. Four of these lineages have been previously described as Neotrygon australiae Last, White and Séret, Neotrygon caeruleopunctata Last, White and Séret, Neotrygon orientale Last, White and Séret, and Neotrygon varidens (Garman), but the morphological characters used in the descriptions offered poor diagnoses and their geographic distributions were not delineated precisely. The objective of the present work is to complete the description of the cryptic species in the complex. Here, an additional four lineages are described as new species on the basis of their mitochondrial DNA sequences: Neotrygon bobwardi, whose distribution extends from the northern tip of Aceh to the western coast of Sumatera; Neotrygon malaccensis, sampled from the eastern part of the Andaman Sea and from the Malacca Strait; Neotrygon moluccensis, from the eastern half of the Banda Sea; and Neotrygon westpapuensis from the central portion of northern West Papua. The geographic distributions of N. australiae, N. coeruleopunctata, N. orientale, and N. varidens are updated. For each species, a diagnosis is provided in the form of a combination of private or partly-private nucleotides at 2-4 nucleotide sites along a 519-base pair fragment of the CO1 gene. We believe that the present taxonomic revision will provide information relevant to the sound management and conservation of cryptic species of the blue-spotted maskray in the Coral Triangle region.

  3. Establishing species distributions in large tropical plant genera: insights from twelve new Thai records of Oberonia (Orchidaceae)

    OpenAIRE

    Bunpha, K.; Pedersen, H.Æ.; Sridith, K.

    2013-01-01

    Establishing species distributions is particularly challenging in large tropical genera of inconspicuous plants. One such genus is Oberonia (Orchidaceae) which we are currently revising for Thailand. When encountering material of a putatively new species, great care has been taken to make a wide geographic search for matching extra-Thai taxa. Against this background, we here record 12 species as new for Thailand: O. dissitiflora, O. evrardii, O. gracilis, O. insectifera, O. lotsyana, O. micro...

  4. Vocalization Source Level Distributions and Pulse Compression Gains of Diverse Baleen Whale Species in the Gulf of Maine

    OpenAIRE

    Delin Wang; Wei Huang; Heriberto Garcia; Purnima Ratilal

    2016-01-01

    The vocalization source level distributions and pulse compression gains are estimated for four distinct baleen whale species in the Gulf of Maine: fin, sei, minke and an unidentified baleen whale species. The vocalizations were received on a large-aperture densely-sampled coherent hydrophone array system useful for monitoring marine mammals over instantaneous wide areas via the passive ocean acoustic waveguide remote sensing technique. For each baleen whale species, between 125 and over 1400 ...

  5. The spatial distribution of threats to plant species with extremely small populations

    Science.gov (United States)

    Wang, Chunjing; Zhang, Jing; Wan, Jizhong; Qu, Hong; Mu, Xianyun; Zhang, Zhixiang

    2017-03-01

    Many biological conservationists take actions to conserve plant species with extremely small populations (PSESP) in China; however, there have been few studies on the spatial distribution of threats to PSESP. Hence, we selected distribution data of PSESP and made a map of the spatial distribution of threats to PSESP in China. First, we used the weight assignment method to evaluate the threat risk to PSESP at both country and county scales. Second, we used a geographic information system to map the spatial distribution of threats to PSESP, and explored the threat factors based on linear regression analysis. Finally, we suggested some effective conservation options. We found that the PSESP with high values of protection, such as the plants with high scientific research values and ornamental plants, were threatened by over-exploitation and utilization, habitat fragmentation, and a small sized wild population in broad-leaved forests and bush fallows. We also identified some risk hotspots for PSESP in China. Regions with low elevation should be given priority for ex- and in-situ conservation. Moreover, climate change should be considered for conservation of PSESP. To avoid intensive over-exploitation or utilization and habitat fragmentation, in-situ conservation should be practiced in regions with high temperatures and low temperature seasonality, particularly in the high risk hotspots for PSESP that we proposed. Ex-situ conservation should be applied in these same regions, and over-exploitation and utilization of natural resources should be prevented. It is our goal to apply the concept of PSESP to the global scale in the future.

  6. Aquatic acute species sensitivity distributions of ZnO and CuO nanoparticles.

    Science.gov (United States)

    Adam, Nathalie; Schmitt, Claudia; De Bruyn, Luc; Knapen, Dries; Blust, Ronny

    2015-09-01

    Metal oxide nanoparticles are increasingly being produced and will inevitably end up in the aquatic environment. Up till now, most papers have studied individual nanoparticle effects. However, the implementation of these data into a risk assessment tool, needed to characterise their risk to the aquatic environment, is still largely lacking. Therefore, aquatic species sensitivity distributions (SSDs) were constructed for ZnO and CuO nanoparticles and 5% hazard concentrations (HC5) were calculated in this study. The effect of individual nanoparticles on these SSDs was estimated by comparison with bulk SSDs. Additionally, the effect of nanoparticle dynamics (aggregation and dissolution) was considered by evaluating the effect of aggregate size on the toxicity, by estimation of the dissolved fraction and comparison with SSDs for ZnCl2 and CuCl2 inorganic salt. Bacteria, protozoa, yeast, rotifera, algae, nematoda, crustacea, hexapoda, fish and amphibia species were included in the analysis. The results show that algae (Zn) and crustacea (Zn, Cu) are the most sensitive species when exposed to the chemicals. Similar acute sensitivity distributions were obtained for ZnO nanoparticles (HC5: 0.06 with 90% confidence interval: 0.03-0.15 mg Zn/l; 43 data points), bulk ZnO (HC5: 0.06 with CI: 0.03-0.20 mg Zn/l; 23 dps) and ZnCl2 (HC5: 0.03 with CI: 0.02-0.05 mg Zn/l; 261 dps). CuO nanoparticles (HC5: 0.15 with CI: 0.05-0.47 mg Cu/l; 43 dps) are more toxic than the bulk materials (HC5: 6.19 with CI: 2.15-38.11 mg Cu/l; 12 dps) but less toxic than CuCl2 (HC5: 0.009 with CI: 0.007-0.012 mg Cu/l; 594 dps) to aquatic species. However, the combined dissolution and SSD results indicate that the toxicity of these nanoparticles is mainly caused by dissolved metal ions. Based on the available information, no current risk of these nanoparticles to the aquatic environment is expected. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Pre- and post-clearcut tree species distribution in two physiographic regions of the Shawnee National Forest, Illinois

    Science.gov (United States)

    Michael A. Long; John W. Groninger

    2010-01-01

    Seventy-four upland oak stands distributed across the Shawnee National Forest, Illinois were inventoried 15 to 26 years after clearcutting and harvest records examined to determine the effect of physiographic province on the distribution of oak and associated tree species before and after clearcutting. Oak represented 62 percent of harvest volume in the Shawnee Hills...

  8. Drivers of extinction risk in African mammals: the interplay of distribution state, human pressure, conservation response and species biology.

    Science.gov (United States)

    Di Marco, Moreno; Buchanan, Graeme M; Szantoi, Zoltan; Holmgren, Milena; Grottolo Marasini, Gabriele; Gross, Dorit; Tranquilli, Sandra; Boitani, Luigi; Rondinini, Carlo

    2014-01-01

    Although conservation intervention has reversed the decline of some species, our success is outweighed by a much larger number of species moving towards extinction. Extinction risk modelling can identify correlates of risk and species not yet recognized to be threatened. Here, we use machine learning models to identify correlates of extinction risk in African terrestrial mammals using a set of variables belonging to four classes: species distribution state, human pressures, conservation response and species biology. We derived information on distribution state and human pressure from satellite-borne imagery. Variables in all four classes were identified as important predictors of extinction risk, and interactions were observed among variables in different classes (e.g. level of protection, human threats, species distribution ranges). Species biology had a key role in mediating the effect of external variables. The model was 90% accurate in classifying extinction risk status of species, but in a few cases the observed and modelled extinction risk mismatched. Species in this condition might suffer from an incorrect classification of extinction risk (hence require reassessment). An increased availability of satellite imagery combined with improved resolution and classification accuracy of the resulting maps will play a progressively greater role in conservation monitoring.

  9. ELNAIS meets EASIN: distribution of marine alien species in Greece using EASIN mapping services and ELNAIS spatial data

    Directory of Open Access Journals (Sweden)

    S. KATSANEVAKIS

    2013-03-01

    Full Text Available The European Alien Species Information Network (EASIN was created with the aim to provide easy access to accurate information on alien species in Europe. EASIN allows the retrieval of spatial information from existing online data providers in order to produce integrated georeferenced distribution maps of alien species in Europe. In November 2012, a new data provider, the Ellenic Network on Aquatic Invasive Species (ELNAIS, joined EASIN; this has significantly increased the available georeferenced information on marine/estuarine alien species in Greek waters. Here, we use maps created by EASIN to show differences in patterns of distribution in Greece for the most abundant Phyla of marine alien species - Mollusca, Arthropoda, Chordata and Annelida. We also show that the two main pathways of introduction of marine alien species (Lessepsian migration and Shipping are related to different patterns of species spatial distribution in Greece. Overall, the tools provided by EASIN can greatly aid scientists and policy makers in obtaining high quality information on marine alien species in Greece, especially after the association with ELNAIS.

  10. Incorporating abundance information and guiding variable selection for climate-based ensemble forecasting of species' distributional shifts

    Science.gov (United States)

    2017-01-01

    Ecological niche models (ENMs) have increasingly been used to estimate the potential effects of climate change on species’ distributions worldwide. Recently, predictions of species abundance have also been obtained with such models, though knowledge about the climatic variables affecting species abundance is often lacking. To address this, we used a well-studied guild (temperate North American quail) and the Maxent modeling algorithm to compare model performance of three variable selection approaches: correlation/variable contribution (CVC), biological (i.e., variables known to affect species abundance), and random. We then applied the best approach to forecast potential distributions, under future climatic conditions, and analyze future potential distributions in light of available abundance data and presence-only occurrence data. To estimate species’ distributional shifts we generated ensemble forecasts using four global circulation models, four representative concentration pathways, and two time periods (2050 and 2070). Furthermore, we present distributional shifts where 75%, 90%, and 100% of our ensemble models agreed. The CVC variable selection approach outperformed our biological approach for four of the six species. Model projections indicated species-specific effects of climate change on future distributions of temperate North American quail. The Gambel’s quail (Callipepla gambelii) was the only species predicted to gain area in climatic suitability across all three scenarios of ensemble model agreement. Conversely, the scaled quail (Callipepla squamata) was the only species predicted to lose area in climatic suitability across all three scenarios of ensemble model agreement. Our models projected future loss of areas for the northern bobwhite (Colinus virginianus) and scaled quail in portions of their distributions which are currently areas of high abundance. Climatic variables that influence local abundance may not always scale up to influence

  11. Climatic controls on the global distribution, abundance, and species richness of mangrove forests

    Science.gov (United States)

    Osland, Michael J.; Feher, Laura C.; Griffith, Kereen; Cavanaugh, Kyle C.; Enwright, Nicholas M.; Day, Richard H.; Stagg, Camille L.; Krauss, Ken W.; Howard, Rebecca J.; Grace, James B.; Rogers, Kerrylee

    2017-01-01

    Mangrove forests are highly productive tidal saline wetland ecosystems found along sheltered tropical and subtropical coasts. Ecologists have long assumed that climatic drivers (i.e., temperature and rainfall regimes) govern the global distribution, structure, and function of mangrove forests. However, data constraints have hindered the quantification of direct climate-mangrove linkages in many parts of the world. Recently, the quality and availability of global-scale climate and mangrove data have been improving. Here, we used these data to better understand the influence of air temperature and rainfall regimes upon the distribution, abundance, and species richness of mangrove forests. Although our analyses identify global-scale relationships and thresholds, we show that the influence of climatic drivers is best characterized via regional range limit-specific analyses. We quantified climatic controls across targeted gradients in temperature and/or rainfall within 14 mangrove distributional range limits. Climatic thresholds for mangrove presence, abundance, and species richness differed among the 14 studied range limits. We identified minimum temperature-based thresholds for range limits in eastern North America, eastern Australia, New Zealand, eastern Asia, eastern South America, and southeast Africa. We identified rainfall-based thresholds for range limits in western North America, western Gulf of Mexico, western South America, western Australia, Middle East, northwest Africa, east central Africa, and west central Africa. Our results show that in certain range limits (e.g., eastern North America, western Gulf of Mexico, eastern Asia), winter air temperature extremes play an especially important role. We conclude that rainfall and temperature regimes are both important in western North America, western Gulf of Mexico, and western Australia. With climate change, alterations in temperature and rainfall regimes will affect the global distribution, abundance, and

  12. A technology framework to analyse the Climate Change impact on biodiversity species distribution

    Science.gov (United States)

    Nativi, S.; Khalsa, S. J.; Geller, G. N.; O'Tuama, E.; Thomas, D.; Mazzetti, P.; Santoro, M.

    2009-04-01

    Several biodiversity application scenarios require modeling the impact of climate change on species distribution. For this purpose, heterogeneous data resources and modeling services are required to interoperate. An information technology and service framework to study the Climate Change impact on biodiversity species distribution is presented. This framework allows the development of relevant biodiversity application scenarios. These draw on data and information exchange from a series of systems interconnected through SOA (Service Oriented Architecture) applying established international standards as well as Community interoperability arrangements. The overall system architecture consists of six main logical components: - Biodiversity Data Provider: a component which is able to provide biodiversity data. - Climatological Data Provider: a component which is able to provide climatological data. - Catalog: a component which is able to perform queries on the available biodiversity and climatological datasets. - Model Provider: a component which is able to run ENM (Ecological Niche Models) on the selected biodiversity and climatological datasets. - Use Scenario Controller: a component which acts as a workflow controller implementing the business process of a typical biodiversity scenario. It is controlled by the user through the GUI. - Graphical User Interface (GUI): The component for user interaction. It controls the workflow manager to perform the required operations for implementing the biodiversity basic scenario. These components play the three typical roles of a SOA where Consumers discover Providers through a Registry. In our framework Data and Model providers are the Service Providers; the GUI-Controller pair acts as a Consumer and the Catalog plays the role of the Registry. Where necessary it also acts as a Broker between Consumer and Providers. This fourth component is necessary for heterogeneous and federated systems. The framework was conceived and

  13. Distribution and abundance of decapod crustacean larvae in the southeastern Bering Sea with emphasis on commercial species. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, D.A.; Incze, L.S.; Wencker, D.L.; Armstrong, J.L.

    1981-01-01

    Contents include: Distribution and abundance of king crab larvae, Paralithodes camtschatica and P. platypus in the southeast Bering Sea; Distribution and abundance of the larvae of tanner crabs in the southeastern Bering Sea; Distribution and abundance of other brachyuran larvae in the southeastern Bering Sea with emphasis on Erimacrus isenbeckii; Distribution and abundance of shrimp larvae in the southeastern Bering Sea with emphasis on pandalid species; Distribution and abundance of hermit crabs (Paguridae) in the southeasternBering Sea; Possible oil impacts on decapod larbae in the southeastern Bering Sea with emphesis on the St. George Basin.

  14. Correlating Velocity Information in the Vicinity of Lagrangian Saddle Points to the Spatially and Temporally Resolved Static Pressure Distribution on a Circular Cylinder

    Science.gov (United States)

    Rockwood, Matthew; Green, Melissa

    2015-11-01

    The l