Trophic position of coexisting krill species: a stable isotope approach

DEFF Research Database (Denmark)

Agersted, Mette Dalgaard; Bode, Antonio; Nielsen, Torkel Gissel

2014-01-01

Four krill species with overlapping functional biology coexist in Greenland waters. Here, we used stable isotopes to investigate and discuss their trophic role and mode of coexistence. Bulk carbon (δ13C) and nitrogen (δ15N) stable isotope analyses of Thysanoessa longicaudata, T. inermis, T. raschii...

Solar Radiation Determines Site Occupancy of Coexisting Tropical and Temperate Deer Species Introduced to New Zealand Forests.

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Robert B Allen

Full Text Available Assemblages of introduced taxa provide an opportunity to understand how abiotic and biotic factors shape habitat use by coexisting species. We tested hypotheses about habitat selection by two deer species recently introduced to New Zealand's temperate rainforests. We hypothesised that, due to different thermoregulatory abilities, rusa deer (Cervus timorensis; a tropical species would prefer warmer locations in winter than red deer (Cervus elaphus scoticus; a temperate species. Since adult male rusa deer are aggressive in winter (the rut, we also hypothesised that rusa deer and red deer would not use the same winter locations. Finally, we hypothesised that in summer both species would prefer locations with fertile soils that supported more plant species preferred as food. We used a 250 × 250 m grid of 25 remote cameras to collect images in a 100-ha montane study area over two winters and summers. Plant composition, solar radiation, and soil fertility were also determined for each camera location. Multiseason occupancy models revealed that direct solar radiation was the best predictor of occupancy and detection probabilities for rusa deer in winter. Multistate, multiseason occupancy models provided strong evidence that the detection probability of adult male rusa deer was greater in winter and when other rusa deer were present at a location. Red deer mostly vacated the study area in winter. For the one season that had sufficient camera images of both species (summer 2011 to allow two-species occupancy models to be fitted, the detection probability of rusa deer also increased with solar radiation. Detection probability also varied with plant composition for both deer species. We conclude that habitat use by coexisting tropical and temperate deer species in New Zealand likely depends on the interplay between the thermoregulatory and behavioural traits of the deer and the abiotic and biotic features of the habitat.

Are trade-offs among species' ecological interactions scale dependent? A test using pitcher-plant inquiline species.

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Kneitel, Jamie M

2012-01-01

Trade-offs among species' ecological interactions is a pervasive explanation for species coexistence. The traits associated with trade-offs are typically measured to mechanistically explain species coexistence at a single spatial scale. However, species potentially interact at multiple scales and this may be reflected in the traits among coexisting species. I quantified species' ecological traits associated with the trade-offs expected at both local (competitive ability and predator tolerance) and regional (competitive ability and colonization rate) community scales. The most common species (four protozoa and a rotifer) from the middle trophic level of a pitcher plant (Sarracenia purpurea) inquiline community were used to link species traits to previously observed patterns of species diversity and abundance. Traits associated with trade-offs (competitive ability, predator tolerance, and colonization rate) and other ecological traits (size, growth rate, and carrying capacity) were measured for each of the focal species. Traits were correlated with one another with a negative relationship indicative of a trade-off. Protozoan and rotifer species exhibited a negative relationship between competitive ability and predator tolerance, indicative of coexistence at the local community scale. There was no relationship between competitive ability and colonization rate. Size, growth rate, and carrying capacity were correlated with each other and the trade-off traits: Size was related to both competitive ability and predator tolerance, but growth rate and carrying capacity were correlated with predator tolerance. When partial correlations were conducted controlling for size, growth rate and carrying capacity, the trade-offs largely disappeared. These results imply that body size is the trait that provides the basis for ecological interactions and trade-offs. Altogether, this study showed that the examination of species' traits in the context of coexistence at different scales

Coexistence via coevolution driven by reduced allelochemical effects and increased tolerance to competition between invasive and native plants.

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Huang, Fangfang; Lankau, Richard; Peng, Shaolin

2018-04-01

Coevolution can promote long-term coexistence of two competing species if selection acts to reduce the fitness inequality between competitors and/or strengthen negative frequency dependence within each population. However, clear coevolution between plant competitors has been rarely documented. Plant invasions offer opportunities to capture the process of coevolution. Here we investigated how the developing relationship between an invasive forb, Alliaria petiolata, and a native competitor, Pilea pumila, may affect their long-term coexistence, by testing the competitive effects of populations of varying lengths of co-occurrence on each other across a chronosequence of invasion history. Alliaria petiolata and P. pumila tended to develop greater tolerance to competition over invasion history. Their coexistence was promoted more by increases in stabilizing relative to equalizing processes. These changes likely stem in part from reductions in allelopathic traits in the invader and evolution of tolerance in the native. These results suggested that some native species can evolve tolerance against the competitive effects of strong invaders, which likely promoted their persistence in invaded communities. However, the potential for coevolutionary rescue of competing populations is likely to vary across native species, and evolutionary processes should not be expected to compensate for the ecological consequences of exotic invasions. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

The coexistence of species La coexistencia de especies

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CALEB E. GORDON

2000-03-01

Full Text Available This paper is a critical literature review on the topic of the coexistence of similar species within ecological communities. A conceptual framework is provided for dividing coexistence studies and concepts into three distinct time scales. The first six sections deal primarily with ecological-scale, or mesoscale coexistence, defined as coexistence in the classic sense of the competitive exclusion principle and Lotka-Volterra models, wherein interacting populations have had enough time to reach equilibrium. The first four sections briefly review resource partitioning studies and competitive coexistence models, and discuss the relative contributions of, and interaction between empirical and theoretical approaches to the problem of ecological-scale coexistence. The next two sections discuss the importance of biological trade-offs and the role of competition in structuring ecological communities. Based on compelling empirical evidence on both sides of the competition debate, a view of competition's role in structuring communities is proposed wherein the effects of competition are important but incomplete. The next section briefly reviews coexistence as it has been incorporated into habitat selection models, which represents coexistence at a finer time scale generated by the behavioral decisions of individual organisms. Linkages between this type of coexistence and mesoscale coexistence are discussed. Finally, a larger scale of coexistence is explored in which the assumptions of fixed niches, habitats, and species pools in communities are relaxed. This section links global and evolutionary species diversity literature to mesoscale ecological coexistence, focusing on the effects of ecosystem productivity and province size. Factors that govern diversity at large scales may be used to calibrate expectations and make predictions about mesoscale coexistence within particular communities. The study of diversity dynamics at geologic time scales suggests some

Woody-Herbaceous Species Coexistence in Mulga Hillslopes: Modelling Structure and Function

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Soltanjalili, M. J.; Saco, P. M.; Willgoose, G. R.

2016-12-01

The fundamental processes underlying the coexistence of woody and herbaceous species in arid and semi-arid areas have been a topic of intense research during the last few decades. Experimental and modelling studies have both supported and disputed alternative hypotheses explaining this phenomenon. Vegetation models including the key processes that drive coexistence can be used to understand vegetation pattern dynamics and structure under current climate conditions, and to predict changes under future conditions. Here we present work done towards linking the observations to modelling. The model captures woody-herbaceous coexistence along a rainfall gradient characteristic of typical conditions on Mulga ecosystems in Australia. The dynamic vegetation model simulates the spatial dynamics of overland flow, soil moisture and vegetation growth of two species. It incorporates key mechanisms for coexistence and pattern formation, including facilitation by evaporation reduction through shading, and infiltration feedbacks, local and non-local seed dispersal, competition for water uptake. Model outcomes, obtained including diflerent mechanisms, are qualitatively compared to typical vegetation cover patterns in the Australian Mulga bioregion where bush fire is very infrequent and the fate of vegetation cover is mostly determined by intra- and interspecies interactions. Through these comparisons, and by drawing on the large number of recent studies that have delivered new insights into the dynamics of such ecosystems, we identify main mechanisms that need an improved representation in the dynamic vegetation models. We show that a realistic parameterization of the model leads to results which are aligned with the observations reported in the literature. At the lower end of the rainfall gradient woody species coexist with herbaceous species within a sparse banded pattern, while at higher rainfall woody species tend to dominate the landscape.

Environmental periodicity and the coexistence problem for two competing and dispersive species

International Nuclear Information System (INIS)

Elion-Mboussa, A.

1994-11-01

The dynamic behaviour of two competing and dispersive species in a heterogeneous space and periodically fluctuating environment is studied. Periodic environmental factors were incorporated into a non-linear reaction-diffusion model, through intrinsic demographic parameters of one of the two species sharing the same favourable space. Furthermore, it was assumed that the physical environmental factors do not have an effect on the growth rate of one of the species. An ecological example of these assumptions is a host- parasite system where parasite reproduction is strongly seasonal, while host populations remain insensitive to physical environmental factors that affect the parasite populations. However, the induced effect of physical environmental factors on the non-affected species was established by means of computer calculations. The periodic oscillations which over the time lead to competitive coexistence of both species with periodic forced oscillations have been shown. It was also shown that, in a periodic environment and under appropriate initial conditions, two competing and dispersive species can coexist when in a constant environment they could not coexist. (author). 25 refs, 12 figs

Trait-fitness relationships determine how trade-off shapes affect species coexistence.

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Ehrlich, Elias; Becks, Lutz; Gaedke, Ursula

2017-12-01

Trade-offs between functional traits are ubiquitous in nature and can promote species coexistence depending on their shape. Classic theory predicts that convex trade-offs facilitate coexistence of specialized species with extreme trait values (extreme species) while concave trade-offs promote species with intermediate trait values (intermediate species). We show here that this prediction becomes insufficient when the traits translate non-linearly into fitness which frequently occurs in nature, e.g., an increasing length of spines reduces grazing losses only up to a certain threshold resulting in a saturating or sigmoid trait-fitness function. We present a novel, general approach to evaluate the effect of different trade-off shapes on species coexistence. We compare the trade-off curve to the invasion boundary of an intermediate species invading the two extreme species. At this boundary, the invasion fitness is zero. Thus, it separates trait combinations where invasion is or is not possible. The invasion boundary is calculated based on measurable trait-fitness relationships. If at least one of these relationships is not linear, the invasion boundary becomes non-linear, implying that convex and concave trade-offs not necessarily lead to different coexistence patterns. Therefore, we suggest a new ecological classification of trade-offs into extreme-favoring and intermediate-favoring which differs from a purely mathematical description of their shape. We apply our approach to a well-established model of an empirical predator-prey system with competing prey types facing a trade-off between edibility and half-saturation constant for nutrient uptake. We show that the survival of the intermediate prey depends on the convexity of the trade-off. Overall, our approach provides a general tool to make a priori predictions on the outcome of competition among species facing a common trade-off in dependence of the shape of the trade-off and the shape of the trait

Trait-based plant ecology: moving towards a unifying species coexistence theory : Features of the Special Section.

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Escudero, Adrián; Valladares, Fernando

2016-04-01

Functional traits are the center of recent attempts to unify key ecological theories on species coexistence and assembling in populations and communities. While the plethora of studies on the role of functional traits to explain patterns and dynamics of communities has rendered a complex picture due to the idiosyncrasies of each study system and approach, there is increasing evidence on their actual relevance when aspects such as different spatial scales, intraspecific variability and demography are considered.

Do competitive interactions in dry heathlands explain plant abundance patterns and species coexistence?

DEFF Research Database (Denmark)

Ransijn, Johannes; Damgaard, Christian; Schmidt, Inger K

2015-01-01

Plant community patterns in space and time may be explained by the interactions between competing plant species. The presented study investigates this in a nutrient and species poor ecosystem. The study presents a methodology for inferring competitive interactions from yearly vegetation inventories...... to predict the community dynamics of C. vulgaris and D. flexuosa. This was compared with the observed plant community structure at 198 Danish dry heathland sites. Interspecific competition will most likely lead to competitive exclusion of D. flexuosa at the observed temporal and spatial scale...... and uses this to assess the outcome of competitive interactions and to predict community patterns and dynamics in a Northwest-European dry heathland. Inferred competitive interactions from five consecutive years of measurements in permanent vegetation frames at a single dry heathland site were used...

The relationship between species richness and ecosystem variability is shaped by the mechanism of coexistence.

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Tredennick, Andrew T; Adler, Peter B; Adler, Frederick R

2017-08-01

Theory relating species richness to ecosystem variability typically ignores the potential for environmental variability to promote species coexistence. Failure to account for fluctuation-dependent coexistence may explain deviations from the expected negative diversity-ecosystem variability relationship, and limits our ability to predict the consequences of increases in environmental variability. We use a consumer-resource model to explore how coexistence via the temporal storage effect and relative nonlinearity affects ecosystem variability. We show that a positive, rather than negative, diversity-ecosystem variability relationship is possible when ecosystem function is sampled across a natural gradient in environmental variability and diversity. We also show how fluctuation-dependent coexistence can buffer ecosystem functioning against increasing environmental variability by promoting species richness and portfolio effects. Our work provides a general explanation for variation in observed diversity-ecosystem variability relationships and highlights the importance of conserving regional species pools to help buffer ecosystems against predicted increases in environmental variability. © 2017 John Wiley & Sons Ltd/CNRS.

Complementarity in nutrient foraging strategies of absorptive fine roots and arbuscular mycorrhizal fungi across 14 coexisting subtropical tree species.

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Liu, Bitao; Li, Hongbo; Zhu, Biao; Koide, Roger T; Eissenstat, David M; Guo, Dali

2015-10-01

In most cases, both roots and mycorrhizal fungi are needed for plant nutrient foraging. Frequently, the colonization of roots by arbuscular mycorrhizal (AM) fungi seems to be greater in species with thick and sparsely branched roots than in species with thin and densely branched roots. Yet, whether a complementarity exists between roots and mycorrhizal fungi across these two types of root system remains unclear. We measured traits related to nutrient foraging (root morphology, architecture and proliferation, AM colonization and extramatrical hyphal length) across 14 coexisting AM subtropical tree species following root pruning and nutrient addition treatments. After root pruning, species with thinner roots showed more root growth, but lower mycorrhizal colonization, than species with thicker roots. Under multi-nutrient (NPK) addition, root growth increased, but mycorrhizal colonization decreased significantly, whereas no significant changes were found under nitrogen or phosphate additions. Moreover, root length proliferation was mainly achieved by altering root architecture, but not root morphology. Thin-root species seem to forage nutrients mainly via roots, whereas thick-root species rely more on mycorrhizal fungi. In addition, the reliance on mycorrhizal fungi was reduced by nutrient additions across all species. These findings highlight complementary strategies for nutrient foraging across coexisting species with contrasting root traits. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

[A Cellular Automata Model for a Community Comprising Two Plant Species of Different Growth Forms].

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Frolov, P V; Zubkova, E V; Komarov, A S

2015-01-01

A cellular automata computer model for the interactions between two plant species of different growth forms--the lime hairgrass Deschampsia caespitosa (L.) P. Beauv., a sod cereal, and the moneywort Lysimachia nummularia L., a ground creeping perennial herb--is considered. Computer experiments on the self-maintenance of the populations of each species against the background of a gradual increase in the share of randomly eliminated individuals, coexistence of the populations of two species, and the effect of the phytogenous field have been conducted. As has been shown, all the studied factors determine the number of individuals and self-sustainability of the simulated populations by the degree of their impact. The limits of action have been determined for individual factors; within these limits, the specific features in plant reproduction and dispersal provide sustainable coexistence of the simulated populations. It has been demonstrated that the constructed model allows for studying the long-term developmental dynamics of the plants belonging to the selected growth forms.

Climate reconstruction analysis using coexistence likelihood estimation (CRACLE): a method for the estimation of climate using vegetation.

Science.gov (United States)

Harbert, Robert S; Nixon, Kevin C

2015-08-01

• Plant distributions have long been understood to be correlated with the environmental conditions to which species are adapted. Climate is one of the major components driving species distributions. Therefore, it is expected that the plants coexisting in a community are reflective of the local environment, particularly climate.• Presented here is a method for the estimation of climate from local plant species coexistence data. The method, Climate Reconstruction Analysis using Coexistence Likelihood Estimation (CRACLE), is a likelihood-based method that employs specimen collection data at a global scale for the inference of species climate tolerance. CRACLE calculates the maximum joint likelihood of coexistence given individual species climate tolerance characterization to estimate the expected climate.• Plant distribution data for more than 4000 species were used to show that this method accurately infers expected climate profiles for 165 sites with diverse climatic conditions. Estimates differ from the WorldClim global climate model by less than 1.5°C on average for mean annual temperature and less than ∼250 mm for mean annual precipitation. This is a significant improvement upon other plant-based climate-proxy methods.• CRACLE validates long hypothesized interactions between climate and local associations of plant species. Furthermore, CRACLE successfully estimates climate that is consistent with the widely used WorldClim model and therefore may be applied to the quantitative estimation of paleoclimate in future studies. © 2015 Botanical Society of America, Inc.

Rising temperature reduces divergence in resource use strategies in coexisting parasitoid species

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Le Lann, C.; Visser, Bertanne; Mériaux, M.; Moiroux, J.; van Baaren, J.; van Alphen, J.M.; Ellers, J.

2014-01-01

Coexistence of species sharing the same resources is often possible if species are phylogenetically divergent in resource acquisition and allocation traits, decreasing competition between them. Developmental and life-history traits related to resource use are influenced by environmental conditions

Transitions and coexistence along a grazing gradient in the Eurasian steppe

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Ren, Haiyan; Taube, Friedelm; Zhang, Yingjun; Bai, Yongfei; Hu, Shuijin

2017-04-01

Ecological resilience theory has often been applied to explain species coexistence and range condition assessment of various community states and to explicate the dynamics of ecosystems. Grazing is a primary disturbance that can alter rangeland resilience by causing hard-to-reverse transitions in grasslands. Yet, how grazing affects the coexistence of plant functional group (PFG) and transition remains unclear. We conducted a six-year grazing experiment in a typical steppe of Inner Mongolia, using seven grazing intensities (0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 sheep/ hectare) and two grazing systems (i.e. a continuous annual grazing as in the traditional grazing system, and a mixed grazing system combining grazing and haymaking), to examine grazing effects on plant functional group shifts and species coexistence in the semi-arid grassland system. Our results indicate that the relative richness of dominant bunchgrasses and forbs had a compensatory coexistence at all grazing intensities, and the richness of rhizomatous grasses fluctuated but was persistent. The relative productivity of dominant bunchgrasses and rhizomatous grasses had compensatory interactions with grazing intensity and grazing system. Dominant bunchgrasses and rhizomatous grasses resist grazing effects by using their dominant species functional traits: high specific leaf area and low leaf nitrogen content. Our results suggest that: 1. Stabilizing mechanisms beyond grazing management are more important in determining plant functional group coexistence and ecological resilience. 2. Plant functional group composition is more important in influencing ecosystem functioning than diversity. 3. Ecosystem resilience at a given level is related to the biomass of dominant PFG, which is determined by a balanced shift between dominant species biomass. The relatively even ecosystem resilience along the grazing gradient is attributed to the compensatory interactions of dominant species in their biomass variations

Geoecohydrological mechanisms couple soil and leaf water dynamics and facilitate species coexistence in shallow soils of a tropical semiarid mixed forest.

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Rodríguez-Robles, Ulises; Arredondo, J Tulio; Huber-Sannwald, Elisabeth; Vargas, Rodrigo

2015-07-01

Trees growing on shallow rocky soils must have exceptional adaptations when underlying weathered bedrock has no deep fractures for water storage. Under semiarid conditions, hydrology of shallow soils is expected to decouple from plant hydrology, as soils dry out as a result of rapid evaporation and competition for water increases between coexisting tree species. Gas exchange and plant-water relations were monitored for 15 months for Pinus cembroides and Quercus potosina tree species in a tropical semiarid forest growing on c. 20-cm-deep soils over impermeable volcanic bedrock. Soil and leaf water potential maintained a relatively constant offset throughout the year in spite of high intra-annual fluctuations reaching up to 5 MPa. Thus, hydrology of shallow soils did not decouple from hydrology of trees even in the driest period. A combination of redistribution mechanisms of water stored in weathered bedrock and hypodermic flow accessible to oak provided the source of water supply to shallow soils, where most of the actively growing roots occurred. This study demonstrates a unique geoecohydrological mechanism that maintains a tightly coupled hydrology between shallow rocky soils and trees, as well as species coexistence in this mixed forest, where oak facilitates water access to pine. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

A Kolmogorov-type competition model with multiple coexistence states and its applications to plant competition for sunlight

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Just, Winfried; Nevai, Andrew L.

2008-12-01

It is demonstrated that a Kolmogorov-type competition model featuring species allocation and gain functions can possess multiple coexistence statesE Two examples are constructed: one in which the two competing species possess rectangular allocation functions but distinct gain functions, and the other in which one species has a rectangular allocation function, the second species has a bi-rectangular allocation function, and the two species share a common gain function. In both examples, it is shown that the species nullclines may intersect multiple times within the interior of the first quadrant, thus creating both locally stable and unstable equilibrium points. These results have important applications in the study of plant competition for sunlight, in which the allocation functions describe the vertical placement of leaves for two competing species, and the gain functions represent rates of photosynthesis performed by leaves at different heights when shaded by overlying leaves belonging to either species.

The Ecohydrologic Role of Coexistence and Competition in Semiarid Hillslopes

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Soltanjalili, M. J.; Saco, P. M.; Willgoose, G. R.

2015-12-01

Through its influence on runoff and erosion-deposition processes, vegetation remarkably regulates different aspects of landscape dynamics. Here, the influence of different plant functional traits on the coexistence of different species in arid and semi-arid regions with patchy vegetation is investigated using an ecohydrology model. The model simulates coevolving changes in biomass patterns for two species, as well as overland flow and soil moisture dynamics. Vegetation patterns emerge as a result of facilitation (shading and infiltration) and competition mechanisms as well as varying seed dispersal strategies. The results show that the survival of only one species or the coexistence of both species not only strongly depends on environmental stresses, but also on differences in hillslope micro and macro topography. These vegetation patterns have very different hydrologic signatures and the potential to trigger remarkably different geomorphic responses. Based on these results we establish new hypothesis that will be used to further investigate the role of plant interspecific and intraspecific feedbacks on landscape coevolution processes.

Arbuscular mycorrhizal fungal diversity and natural enemies promote coexistence of tropical tree species

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Benedicte Bachelot; María Uriarte; Krista L. McGuire; Jill Thompson; Jess Zimmerman

2017-01-01

Negative population feedbacks mediated by natural enemies can promote species coexistence at the community scale through disproportionate mortality of numerically dominant (common) tree species. Simultaneously, associations with arbuscular mycorrhizal fungi (AMF) can result in positive effects on tree populations. Coupling data on seedling foliar damage from herbivores...

Ecological modules and roles of species in heathland plant-insect flower visitor networks

DEFF Research Database (Denmark)

Dupont, Yoko; Olesen, Jens Mogens

2009-01-01

1.  Co-existing plants and flower-visiting animals often form complex interaction networks. A long-standing question in ecology and evolutionary biology is how to detect nonrandom subsets (compartments, blocks, modules) of strongly interacting species within such networks. Here we use a network...... analytical approach to (i) detect modularity in pollination networks, (ii) investigate species composition of modules, and (iii) assess the stability of modules across sites. 2.  Interactions between entomophilous plants and their flower-visitors were recorded throughout the flowering season at three...... heathland sites in Denmark, separated by ≥ 10 km. Among sites, plant communities were similar, but composition of flower-visiting insect faunas differed. Visitation frequencies of visitor species were recorded as a measure of insect abundance. 3.  Qualitative (presence-absence) interaction networks were...

Octocoral Species Assembly and Coexistence in Caribbean Coral Reefs.

Science.gov (United States)

Velásquez, Johanna; Sánchez, Juan A

2015-01-01

What are the determinant factors of community assemblies in the most diverse ecosystem in the ocean? Coral reefs can be divided in continental (i.e., reefs that develop on the continental shelf, including siliciclastic reefs) and oceanic (i.e., far off the continental shelf, usually on volcanic substratum); whether or not these habitat differences impose community-wide ecological divergence or species exclusion/coexistence with evolutionary consequences, is unknown. Studying Caribbean octocorals as model system, we determined the phylogenetic community structure in a coral reef community, making emphasis on species coexistence evidenced on trait evolution and environmental feedbacks. Forty-nine species represented in five families constituted the species pool from which a phylogenetic tree was reconstructed using mtDNA. We included data from 11 localities in the Western Caribbean (Colombia) including most reef types. To test diversity-environment and phenotype-environment relationships, phylogenetic community structure and trait evolution we carried out comparative analyses implementing ecological and evolutionary approaches. Phylogenetic inferences suggest clustering of oceanic reefs (e.g., atolls) contrasting with phylogenetic overdispersion of continental reefs (e.g., reefs banks). Additionally, atolls and barrier reefs had the highest species diversity (Shannon index) whereas phylogenetic diversity was higher in reef banks. The discriminant component analysis supported this differentiation between oceanic and continental reefs, where continental octocoral species tend to have greater calyx apertures, thicker branches, prominent calyces and azooxanthellate species. This analysis also indicated a clear separation between the slope and the remaining habitats, caused by the presence or absence of Symbiodinium. K statistic analysis showed that this trait is conserved as well as the branch shape. There was strong octocoral community structure with opposite diversity

Octocoral Species Assembly and Coexistence in Caribbean Coral Reefs.

Directory of Open Access Journals (Sweden)

Johanna Velásquez

Full Text Available What are the determinant factors of community assemblies in the most diverse ecosystem in the ocean? Coral reefs can be divided in continental (i.e., reefs that develop on the continental shelf, including siliciclastic reefs and oceanic (i.e., far off the continental shelf, usually on volcanic substratum; whether or not these habitat differences impose community-wide ecological divergence or species exclusion/coexistence with evolutionary consequences, is unknown.Studying Caribbean octocorals as model system, we determined the phylogenetic community structure in a coral reef community, making emphasis on species coexistence evidenced on trait evolution and environmental feedbacks. Forty-nine species represented in five families constituted the species pool from which a phylogenetic tree was reconstructed using mtDNA. We included data from 11 localities in the Western Caribbean (Colombia including most reef types. To test diversity-environment and phenotype-environment relationships, phylogenetic community structure and trait evolution we carried out comparative analyses implementing ecological and evolutionary approaches.Phylogenetic inferences suggest clustering of oceanic reefs (e.g., atolls contrasting with phylogenetic overdispersion of continental reefs (e.g., reefs banks. Additionally, atolls and barrier reefs had the highest species diversity (Shannon index whereas phylogenetic diversity was higher in reef banks. The discriminant component analysis supported this differentiation between oceanic and continental reefs, where continental octocoral species tend to have greater calyx apertures, thicker branches, prominent calyces and azooxanthellate species. This analysis also indicated a clear separation between the slope and the remaining habitats, caused by the presence or absence of Symbiodinium. K statistic analysis showed that this trait is conserved as well as the branch shape.There was strong octocoral community structure with opposite

Patterns of temporal and enemy niche use by a community of leaf cone moths (Caloptilia) coexisting on maples (Acer) as revealed by metabarcoding.

Science.gov (United States)

Nakadai, Ryosuke; Kawakita, Atsushi

2017-06-01

The diversity of herbivorous insects is often considered a function of host plant diversity. However, recent research has uncovered many examples of closely related herbivores using the same host plant(s), suggesting that partitioning of host plants is not the only mechanism generating diversity. Herbivores sharing hosts may utilize different parts of the same plant, but such resource partitioning is often not apparent; hence, the factors that allow closely related herbivores to coexist are still largely undetermined. We examined whether partitioning of phenology or natural enemies may explain the coexistence of leaf cone moths (Caloptilia; Gracillariidae) associated with maples (Acer; Sapindaceae). Larval activity of 10 sympatric Caloptilia species found on nine maple species was monitored every 2-3 weeks for a total of 13 sampling events, and an exhaustive search for internal parasitoid wasps was conducted using high-throughput sequencing. Blocking primers were used to facilitate the detection of wasp larvae inside moth tissue. We found considerable phenological overlap among Caloptilia species, with two clear peaks in July and September-October. Coexisting Caloptilia species also had largely overlapping parasitoid communities; a total of 13 chalcid and ichneumon wasp species attacked Caloptilia in a nonspecific fashion at an overall parasitism rate of 46.4%. Although coexistence may be facilitated by factors not accounted for in this study, it appears that niche partitioning is not necessary for closely related herbivores to stably coexist on shared hosts. Co-occurrence without resource partitioning may provide an additional axis along which herbivorous insects attain increased species richness. © 2017 John Wiley & Sons Ltd.

Dispersal and life span spectra in plant communities : a key to safe site dynamics, species coexistence and conservation

NARCIS (Netherlands)

Strykstra, RJ; Bekker, RM; Van Andel, J

Dispersal and life span of individual plant species within five plant communities were assessed to obtain a characterization of these communities in this respect. Such a characterization is important in the context of restoration and maintenance. The most frequent species of five communities were

Genetic variation for sensitivity to a thyme monoterpene in associated plant species.

Science.gov (United States)

Jensen, Catrine Grønberg; Ehlers, Bodil Kirstine

2010-04-01

Recent studies have shown that plant allelochemicals can have profound effects on the performance of associated species, such that plants with a history of co-existence with "chemical neighbour" plants perform better in their presence compared to naïve plants. This has cast new light on the complexity of plant-plant interactions and plant communities and has led to debates on whether plant communities are more co-evolved than traditionally thought. In order to determine whether plants may indeed evolve in response to other plants' allelochemicals it is crucial to determine the presence of genetic variation for performance under the influence of specific allelochemicals and show that natural selection indeed operates on this variation. We studied the effect of the monoterpene carvacrol-a dominant compound in the essential oil of Thymus pulegioides-on three associated plant species originating from sites where thyme is either present or absent. We found the presence of genetic variation in both naïve and experienced populations for performance under the influence of the allelochemical but the response varied among naïve and experienced plant. Plants from experienced populations performed better than naïve plants on carvacrol soil and contained significantly more seed families with an adaptive response to carvacrol than naïve populations. This suggests that the presence of T. pulegioides can act as a selective agent on associated species, by favouring genotypes which perform best in the presence of its allelochemicals. The response to the thyme allelochemical varied from negative to neutral to positive among the species. The different responses within a species suggest that plant-plant interactions can evolve; this has implications for community dynamics and stability.

Individual-based ant-plant networks: diurnal-nocturnal structure and species-area relationship.

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Wesley Dáttilo

Full Text Available Despite the importance and increasing knowledge of ecological networks, sampling effort and intrapopulation variation has been widely overlooked. Using continuous daily sampling of ants visiting three plant species in the Brazilian Neotropical savanna, we evaluated for the first time the topological structure over 24 h and species-area relationships (based on the number of extrafloral nectaries available in individual-based ant-plant networks. We observed that diurnal and nocturnal ant-plant networks exhibited the same pattern of interactions: a nested and non-modular pattern and an average level of network specialization. Despite the high similarity in the ants' composition between the two collection periods, ant species found in the central core of highly interacting species totally changed between diurnal and nocturnal sampling for all plant species. In other words, this "night-turnover" suggests that the ecological dynamics of these ant-plant interactions can be temporally partitioned (day and night at a small spatial scale. Thus, it is possible that in some cases processes shaping mutualistic networks formed by protective ants and plants may be underestimated by diurnal sampling alone. Moreover, we did not observe any effect of the number of extrafloral nectaries on ant richness and their foraging on such plants in any of the studied ant-plant networks. We hypothesize that competitively superior ants could monopolize individual plants and allow the coexistence of only a few other ant species, however, other alternative hypotheses are also discussed. Thus, sampling period and species-area relationship produces basic information that increases our confidence in how individual-based ant-plant networks are structured, and the need to consider nocturnal records in ant-plant network sampling design so as to decrease inappropriate inferences.

Interference competition as a mechanism of coexistence between two sympatric species of the grass shrimp Palaemonetes (Decapoda: Palaemonidae)

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Thorp, J.H.

1976-01-01

Various theories have been developed to explain the puzzling coexistence of species which have broad niche overlap in critical resource utilization. The coexistence of two sympatric species of grass shrimp, Palaemonetes pugio Holthuis and p. vulgaris (Say), whose niches overlap with respect to space, food, and time, was examined in an experimental field and laboratory study. A seasonal fluctuation between sympatric and contiguous allopatric distribution of the two species of grass shrimp on natural shell, mud, and eelgrass substrata suggests that competition may be an important factor determining distribution of Palaemonetes. Field and laboratory experiments confirm that P. vulgaris can competitively displace P. pugio from the preferred shell substratum by interference competition but the tendency of grass shrimp to separate spatially in winter by bottom-depths (as in field enclosure cages) could have allowed both species to coexist on shell. Spatial separation by bottom-depth was not so evident in spring, since P. vulgaris apparently displaced P. pugio from shell to mud substratum. Occupancy of shell substratum is shown to be adaptive in that shell provides greater protection from predators than does mud. It is suggested that the spatial partitioning resulting from this interference competition promotes coexistence by reducing agonism while permitting efficient utilization of other common resources.

Species coexistence and the superior ability of an invasive species to exploit a facilitation cascade habitat

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Andrew H. Altieri

2017-02-01

Full Text Available Facilitation cascades generated by co-occurring foundation species can enhance the abundance and diversity of associated organisms. However, it remains poorly understood how differences among native and invasive species in their ability to exploit these positive interactions contribute to emergent patterns of community structure and biotic acceptance. On intertidal shorelines in New England, we examined the patterns of coexistence between the native mud crabs and the invasive Asian shore crab in and out of a facilitation cascade habitat generated by mid intertidal cordgrass and ribbed mussels. These crab species co-occurred in low intertidal cobbles adjacent to the cordgrass–mussel beds, despite experimental findings that the dominant mud crabs can kill and displace Asian shore crabs and thereby limit their successful recruitment to their shared habitat. A difference between the native and invasive species in their utilization of the facilitation cascade likely contributes to this pattern. Only the Asian shore crabs inhabit the cordgrass–mussel beds, despite experimental evidence that both species can similarly benefit from stress amelioration in the beds. Moreover, only Asian shore crabs settle in the beds, which function as a nursery habitat free of lethal mud crabs, and where their recruitment rates are particularly high (nearly an order of magnitude higher than outside beds. Persistence of invasive adult Asian shore crabs among the dominant native mud crabs in the low cobble zone is likely enhanced by a spillover effect of the facilitation cascade in which recruitment-limited Asian shore crabs settle in the mid intertidal cordgrass–mussel beds and subsidize their vulnerable populations in the adjacent low cobble zone. This would explain why the abundances of Asian shore crabs in cobbles are doubled when adjacent to facilitation cascade habitats. The propensity for this exotic species to utilize habitats created by facilitation cascades

Negative plant-phyllosphere feedbacks in native Asteraceae hosts - a novel extension of the plant-soil feedback framework.

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Whitaker, Briana K; Bauer, Jonathan T; Bever, James D; Clay, Keith

2017-08-01

Over the past 25 years, the plant-soil feedback (PSF) framework has catalyzed our understanding of how belowground microbiota impact plant fitness and species coexistence. Here, we apply a novel extension of this framework to microbiota associated with aboveground tissues, termed 'plant-phyllosphere feedback (PPFs)'. In parallel greenhouse experiments, rhizosphere and phyllosphere microbiota of con- and heterospecific hosts from four species were independently manipulated. In a third experiment, we tested the combined effects of soil and phyllosphere feedback under field conditions. We found that three of four species experienced weak negative PSF whereas, in contrast, all four species experienced strong negative PPFs. Field-based feedback estimates were highly negative for all four species, though variable in magnitude. Our results suggest that phyllosphere microbiota, like rhizosphere microbiota, can potentially mediate plant species coexistence via negative feedbacks. Extension of the PSF framework to the phyllosphere is needed to more fully elucidate plant-microbiota interactions. © 2017 John Wiley & Sons Ltd/CNRS.

Coexistence of three specialist aphids on common milkweed, Asclepias syriaca.

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Smith, R A; Mooney, K A; Agrawal, A A

2008-08-01

Coexistence of host-specific herbivores on plants is believed to be governed by interspecific interactions, but few empirical studies have systematically unraveled these dynamics. We investigated the role of several factors in promoting coexistence among the aphids Aphis nerii, Aphis asclepiadis, and Myzocallis asclepiadis that all specialize on common milkweed (Asclepias syriaca). Competitive exclusion is thought to occur when interspecific competition is stronger than intraspecific competition. Consequently, we investigated whether predators, mutualists, or resource quality affected the strength of intra- vs. interspecific competition among aphids in factorial manipulations of competition with exposure to predation, ants, and variable plant genotypes in three separate experiments. In the predation x competition experiment, predators reduced aphid per capita growth by 66%, but the strength of intra- and interspecific competition did not depend on predators. In the ants x competition experiment, ants reduced per capita growth of A. nerii and M. asclepiadis (neither of which were mutualists with ants) by approximately one-half. In so doing, ants ameliorated the negative effects of these competitors on ant-tended A. asclepiadis by two-thirds, representing a novel benefit of ant-aphid mutualism. Nevertheless, ants alone did not explain the persistence of competitively inferior A. asclepiadis as, even in the presence of ants, interspecific competition remained stronger than intraspecific competition. In the plant genotype x competition experiment, both A. asclepiadis and M. asclepiadis were competitively inferior to A. nerii, with the strength of interspecific competition exceeding that of intraspecific competition by 83% and 23%, respectively. Yet these effects differed among milkweed genotypes, and there were one or more plant genotypes for each aphid species where coexistence was predicted. A synthesis of our results shows that predators play little or no role in

Coexistence of structured populations with size-based prey selection

DEFF Research Database (Denmark)

Hartvig, Martin; Andersen, Ken Haste

2013-01-01

Abstract Species with a large adult-offspring size ratio and a preferred predator–prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending on the ma......Abstract Species with a large adult-offspring size ratio and a preferred predator–prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending...... on the maximum adult sizes and population size distributions. We explore the assembly and potential for coexistence of small communities where all species experience ontogenetic trophic niche shifts. The life-history of each species is described by a physiologically structured model and species identity...... there is a large scope for coexistence of two species, the scope for coexistence of three species is limited and we conclude that further trait differentiation is required for coexistence of more species-rich size-structured communities....

Tree competition and species coexistence in a Quercus--Betula forest in the Dongling Mountains in northern China

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Hou, Ji-hua; Mi, Xiang-cheng; Liu, Can-ran; Ma, Ke-ping

2006-09-01

The population size structure, growth dynamics and mode of competition among adult trees (≥ 4 cm DBH) of six abundant tree species in a 5 ha study plot of a temperate deciduous forest in the Dongling Mountains in northern China were investigated using diffusion and growth dynamics models. In the year of 2000, two dominant species, Quercus liaotungensis and Betula dahurica accounted for ca. 68.69% of the total basal area and 52.71% of the total density of adult plants. Q. liaotungensis, Populus davidiana and Acer mono exhibited inverse J-shaped DBH distributions whereas Betula dahurica, B. platyphylla and Salix caprea had unimodal DBH distributions. One-sided interspecific competition was detected between some species combinations at the scale of the 5 ha study plot, and the competitive effect was mainly size-dependent rather than from species-specific interactions with large individuals in the canopy layer out competing smaller individuals in the understory. Symmetric competition was found between Q. liaotungensis and A. mono only. However, considering the straight line relationship of G ( t, x) - √{D(t, x)}, which suggests that competitive asymmetry is very low or absent, combined with the relatively low mortality of trees with a DBH larger than 4 cm, we speculate that asymmetric interspecific competition was not important in structuring this tree community. Regeneration characteristics of each species are most likely important in regulating species coexistence and stand dynamics in this forest.

Testing spatial theories of plant coexistence: no consistent differences in intra- and interspecific interaction distances.

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Vogt, Deborah R; Murrell, David J; Stoll, Peter

2010-01-01

Plants stand still and interact with their immediate neighbors. Theory has shown that the distances over which these interactions occur may have important consequences for population and community dynamics. In particular, if intraspecific competition occurs over longer distances than interspecific competition (heteromyopia), coexistence can be promoted. We examined how intraspecific and interspecific competition scales with neighbor distance in a target-neighbor greenhouse competition experiment. Individuals from co-occurring forbs from calcareous grasslands were grown in isolation and with single conspecific or heterospecific neighbors at distances of 5, 10, or 15 cm (Plantago lanceolata vs. Plantago media and Hieracium pilosella vs. Prunella grandiflora). Neighbor effects were strong and declined with distance. Interaction distances varied greatly within and between species, but we found no evidence for heteromyopia. Instead, neighbor identity effects were mostly explained by relative size differences between target and neighbor. We found a complex interaction between final neighbor size and identity such that neighbor identity may become important only as the neighbor becomes very large compared with the target individual. Our results suggest that species-specific size differences between neighboring individuals determine both the strength of competitive interactions and the distance over which these interactions occur.

Functional diversity of microbial decomposers facilitates plant coexistence in a plant-microbe-soil feedback model.

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Miki, Takeshi; Ushio, Masayuki; Fukui, Shin; Kondoh, Michio

2010-08-10

Theory and empirical evidence suggest that plant-soil feedback (PSF) determines the structure of a plant community and nutrient cycling in terrestrial ecosystems. The plant community alters the nutrient pool size in soil by affecting litter decomposition processes, which in turn shapes the plant community, forming a PSF system. However, the role of microbial decomposers in PSF function is often overlooked, and it remains unclear whether decomposers reinforce or weaken litter-mediated plant control over nutrient cycling. Here, we present a theoretical model incorporating the functional diversity of both plants and microbial decomposers. Two fundamental microbial processes are included that control nutrient mineralization from plant litter: (i) assimilation of mineralized nutrient into the microbial biomass (microbial immobilization), and (ii) release of the microbial nutrients into the inorganic nutrient pool (net mineralization). With this model, we show that microbial diversity may act as a buffer that weakens plant control over the soil nutrient pool, reversing the sign of PSF from positive to negative and facilitating plant coexistence. This is explained by the decoupling of litter decomposability and nutrient pool size arising from a flexible change in the microbial community composition and decomposition processes in response to variations in plant litter decomposability. Our results suggest that the microbial community plays a central role in PSF function and the plant community structure. Furthermore, the results strongly imply that the plant-centered view of nutrient cycling should be changed to a plant-microbe-soil feedback system, by incorporating the community ecology of microbial decomposers and their functional diversity.

Body size mediated coexistence in swans.

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Engelhardt, Katharina A M; Ritchie, Mark E; Powell, James A

2014-01-01

Differences in body sizes may create a trade-off between foraging efficiency (foraging gains/costs) and access to resources. Such a trade-off provides a potential mechanism for ecologically similar species to coexist on one resource. We explored this hypothesis for tundra (Cygnus columbianus) and trumpeter swans (Cygnus buccinator), a federally protected species, feeding solely on sago pondweed (Stuckenia pectinata) tubers during fall staging and wintering in northern Utah. Foraging efficiency was higher for tundra swans because this species experienced lower foraging and metabolic costs relative to foraging gains; however, trumpeter swans (a) had longer necks and therefore had access to exclusive resources buried deep in wetland sediments and (b) were more aggressive and could therefore displace tundra swans from lucrative foraging locations. We conclude that body size differentiation is an important feature of coexistence among ecologically similar species feeding on one resource. In situations where resources are limiting and competition for resources is strong, conservation managers will need to consider the trade-off between foraging efficiency and access to resources to ensure ecologically similar species can coexist on a shared resource.

Plant toxicity, adaptive herbivory, and plant community dynamics

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Feng, Z.; Liu, R.; DeAngelis, D.L.; Bryant, J.P.; Kielland, K.; Stuart, Chapin F.; Swihart, R.K.

2009-01-01

We model effects of interspecific plant competition, herbivory, and a plant's toxic defenses against herbivores on vegetation dynamics. The model predicts that, when a generalist herbivore feeds in the absence of plant toxins, adaptive foraging generally increases the probability of coexistence of plant species populations, because the herbivore switches more of its effort to whichever plant species is more common and accessible. In contrast, toxin-determined selective herbivory can drive plant succession toward dominance by the more toxic species, as previously documented in boreal forests and prairies. When the toxin concentrations in different plant species are similar, but species have different toxins with nonadditive effects, herbivores tend to diversify foraging efforts to avoid high intakes of any one toxin. This diversification leads the herbivore to focus more feeding on the less common plant species. Thus, uncommon plants may experience depensatory mortality from herbivory, reducing local species diversity. The depensatory effect of herbivory may inhibit the invasion of other plant species that are more palatable or have different toxins. These predictions were tested and confirmed in the Alaskan boreal forest. ?? 2009 Springer Science+Business Media, LLC.

Species of the Hoplias aff malabaricus complex (Characiformes: Erythrinidae: An investigation of coexistence in a Neotropical floodplain

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Marília Hauser

2012-02-01

Full Text Available This study assessed the coexistence of three species of thraira present in the Upper Paraná River floodplain, using population structure as an investigation tool. The species were designated as: Hoplias sp. 1, introduced after the construction of the Itaipu reservoir, and Hoplias sp. 2 and Hoplias sp. 3, native species that have been identified as Hoplias aff. malabaricus. We tested the hypothesis that those species in fact differ from each other in respect of population abundance, sex ratio, relative frequency of adults and juveniles, length structure and weight-length relationship. Additionally, possible effects of the flood pulse on the first four of these parameters were investigated. Samples were collected quarterly from March 2006 to December 2007 from nine collection sites on the floodplain. Hoplias sp. 1 presented a greater balance of sex ratio and length structures over the seasons, as well as a higher allometric coefficient. The population attributes of Hoplias sp. 2 and Hoplias sp. 3 showed a high responsiveness to hydrological seasonality, indicating that these species exploit available resources in a conspicuous flood period with greater efficiency. These differences, beyond reflecting possible mechanisms that allow closely related species to coexist, indicate the importance of understanding the life strategies adopted by each species which, as part of a complex system, are considered key elements of the aquatic community structure in the region, providing important information for habitat management and biodiversity conservation.

Body Size Mediated Coexistence in Swans

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Katharina A. M. Engelhardt

2014-01-01

Full Text Available Differences in body sizes may create a trade-off between foraging efficiency (foraging gains/costs and access to resources. Such a trade-off provides a potential mechanism for ecologically similar species to coexist on one resource. We explored this hypothesis for tundra (Cygnus columbianus and trumpeter swans (Cygnus buccinator, a federally protected species, feeding solely on sago pondweed (Stuckenia pectinata tubers during fall staging and wintering in northern Utah. Foraging efficiency was higher for tundra swans because this species experienced lower foraging and metabolic costs relative to foraging gains; however, trumpeter swans (a had longer necks and therefore had access to exclusive resources buried deep in wetland sediments and (b were more aggressive and could therefore displace tundra swans from lucrative foraging locations. We conclude that body size differentiation is an important feature of coexistence among ecologically similar species feeding on one resource. In situations where resources are limiting and competition for resources is strong, conservation managers will need to consider the trade-off between foraging efficiency and access to resources to ensure ecologically similar species can coexist on a shared resource.

Coexistence of two freshwater turtle species along a Mediterranean stream: The role of spatial and temporal heterogeneity

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Segurado, Pedro; Figueiredo, Diogo

2007-09-01

In the Iberian Peninsula the European pond turtle ( Emys orbicularis) and the Mediterranean pond turtle ( Mauremys leprosa) share many freshwater habitats, in particular Mediterranean streams. Whether and how these two species divide space within those habitats is poorly known in part due to the very low abundance of E. orbicularis at most syntopic sites. The spatial coexistence of these two species was studied along a 1.3 km reach of a typical Mediterranean stream based on data from trapping sessions and basking counts. The effect of the hydrological regime on differences in space use between species was also assessed. Spatial associations between species and between each species and microhabitat descriptors were estimated using a permutation procedure to account for spatial autocorrelation. Differences in the use of space were also estimated using a resample technique to account for the small sample sizes of E. orbicularis. Results indicate that E. orbicularis shows a preference for temporary, shallow, well vegetated and sandy reaches, while M. leprosa is less selective regarding microhabitat. Differences between E. orbicularis and juveniles of M. leprosa were less obvious. The high spatial heterogeneity of Mediterranean streams may be responsible for the persistence of viable populations of E. orbicularis as well as favouring the coexistence of the two turtle species. Therefore, stream habitat management and conservation plans for E. orbicularis should give priority to the maintenance of high levels of heterogeneity along Mediterranean streams.

Fungal communities in wheat grain show significant co-existence patterns among species

DEFF Research Database (Denmark)

Nicolaisen, M.; Justesen, A. F.; Knorr, K.

2014-01-01

identified as ‘core’ OTUs as they were found in all or almost all samples and accounted for almost 99 % of all sequences. The remaining OTUs were only sporadically found and only in small amounts. Cluster and factor analyses showed patterns of co-existence among the core species. Cluster analysis grouped...... the 21 core OTUs into three clusters: cluster 1 consisting of saprotrophs, cluster 2 consisting mainly of yeasts and saprotrophs and cluster 3 consisting of wheat pathogens. Principal component extraction showed that the Fusarium graminearum group was inversely related to OTUs of clusters 1 and 2....

Species Coexistence in Nitrifying Chemostats: A Model of Microbial Interactions

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Maxime Dumont

2016-12-01

Full Text Available In a previous study, the two nitrifying functions (ammonia oxidizing bacteria (AOB or nitrite-oxidizing bacteria (NOB of a nitrification reactor—operated continuously over 525 days with varying inputs—were assigned using a mathematical modeling approach together with the monitoring of bacterial phylotypes. Based on these theoretical identifications, we develop here a chemostat model that does not explicitly include only the resources’ dynamics (different forms of soluble nitrogen but also explicitly takes into account microbial inter- and intra-species interactions for the four dominant phylotypes detected in the chemostat. A comparison of the models obtained with and without interactions has shown that such interactions permit the coexistence of two competing ammonium-oxidizing bacteria and two competing nitrite-oxidizing bacteria in competition for ammonium and nitrite, respectively. These interactions are analyzed and discussed.

Exotic plant species attack revegetation plants in post-coal mining areas

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Yusuf, Muhammad; Arisoesilaningsih, Endang

2017-11-01

This study aimed to explore some invasive exotic plant species that have the potential to disrupt the growth of revegetation plants in post-coal mining areas. This research was conducted in a revegetation area of PT, Amanah Anugerah Adi Mulia (A3M) Kintap site, South Borneo. Direct observation was carried out on some revegetation areas by observing the growth of revegetation plants disturbed by exotic plant species and the spread of exotic plant species. Based on observation, several invasive exotic plant species were identified including Mikania cordata, Centrosema pubescence, Calopogonium mucunoides, Mimosa pudica, Ageratum conyzoides, and Chromolaena odorata. These five plant species grew wild in the revegetation area and showed ability to disrupt the growth of other plants. In some tree species, such as Acacia mangium, Paraserianthes falcataria, M. cordata could inhibit the growth and even kill the trees through covering the tree canopy. So, the trees could not receive optimum sun light for photosynthesis processes. M. cordata was also observed to have the most widespread distribution. Several exotic plant species such as C. mucunoides, M. pudica, and A. conyzoides were observed to have deep root systems compared with plant species used for revegetation. This growth characteristic allowed exotic plant species to win the competition for nutrient absorption with other plant species.

Differential growth responses to water balance of coexisting deciduous tree species are linked to wood density in a Bolivian tropical dry forest.

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Mendivelso, Hooz A; Camarero, J Julio; Royo Obregón, Oriol; Gutiérrez, Emilia; Toledo, Marisol

2013-01-01

A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability.

The nature of plant species.

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Rieseberg, Loren H; Wood, Troy E; Baack, Eric J

2006-03-23

Many botanists doubt the existence of plant species, viewing them as arbitrary constructs of the human mind, as opposed to discrete, objective entities that represent reproductively independent lineages or 'units of evolution'. However, the discreteness of plant species and their correspondence with reproductive communities have not been tested quantitatively, allowing zoologists to argue that botanists have been overly influenced by a few 'botanical horror stories', such as dandelions, blackberries and oaks. Here we analyse phenetic and/or crossing relationships in over 400 genera of plants and animals. We show that although discrete phenotypic clusters exist in most genera (> 80%), the correspondence of taxonomic species to these clusters is poor (< 60%) and no different between plants and animals. Lack of congruence is caused by polyploidy, asexual reproduction and over-differentiation by taxonomists, but not by contemporary hybridization. Nonetheless, crossability data indicate that 70% of taxonomic species and 75% of phenotypic clusters in plants correspond to reproductively independent lineages (as measured by postmating isolation), and thus represent biologically real entities. Contrary to conventional wisdom, plant species are more likely than animal species to represent reproductively independent lineages.

Spatial heterogeneity of plant-soil feedback affects root interactions and interspecific competition.

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Hendriks, Marloes; Ravenek, Janneke M; Smit-Tiekstra, Annemiek E; van der Paauw, Jan Willem; de Caluwe, Hannie; van der Putten, Wim H; de Kroon, Hans; Mommer, Liesje

2015-08-01

Plant-soil feedback is receiving increasing interest as a factor influencing plant competition and species coexistence in grasslands. However, we do not know how spatial distribution of plant-soil feedback affects plant below-ground interactions. We investigated the way in which spatial heterogeneity of soil biota affects competitive interactions in grassland plant species. We performed a pairwise competition experiment combined with heterogeneous distribution of soil biota using four grassland plant species and their soil biota. Patches were applied as quadrants of 'own' and 'foreign' soils from all plant species in all pairwise combinations. To evaluate interspecific root responses, species-specific root biomass was quantified using real-time PCR. All plant species suffered negative soil feedback, but strength was species-specific, reflected by a decrease in root growth in own compared with foreign soil. Reduction in root growth in own patches by the superior plant competitor provided opportunities for inferior competitors to increase root biomass in these patches. These patterns did not cascade into above-ground effects during our experiment. We show that root distributions can be determined by spatial heterogeneity of soil biota, affecting plant below-ground competitive interactions. Thus, spatial heterogeneity of soil biota may contribute to plant species coexistence in species-rich grasslands. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Differential growth responses to water balance of coexisting deciduous tree species are linked to wood density in a Bolivian tropical dry forest.

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Hooz A Mendivelso

Full Text Available A seasonal period of water deficit characterizes tropical dry forests (TDFs. There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability.

Differential Growth Responses to Water Balance of Coexisting Deciduous Tree Species Are Linked to Wood Density in a Bolivian Tropical Dry Forest

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Mendivelso, Hooz A.; Camarero, J. Julio; Royo Obregón, Oriol; Gutiérrez, Emilia; Toledo, Marisol

2013-01-01

A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability. PMID:24116001

Invasive plant species alters consumer behavior by providing refuge from predation.

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Dutra, Humberto P; Barnett, Kirk; Reinhardt, Jason R; Marquis, Robert J; Orrock, John L

2011-07-01

Understanding the effects of invasive plants on native consumers is important because consumer-mediated indirect effects have the potential to alter the dynamics of coexistence in native communities. Invasive plants may promote changes in consumer pressure due to changes in protective cover (i.e., the architectural complexity of the invaded habitat) and in food availability (i.e., subsidies of fruits and seeds). No experimental studies have evaluated the relative interplay of these two effects. In a factorial experiment, we manipulated cover and food provided by the invasive shrub Amur honeysuckle (Lonicera maackii) to evaluate whether this plant alters the foraging activity of native mammals. Using tracking plates to quantify mammalian foraging activity, we found that removal of honeysuckle cover, rather than changes in the fruit resources it provides, reduced the activity of important seed consumers, mice in the genus Peromyscus. Two mesopredators, Procyon lotor and Didelphis virginiana, were also affected. Moreover, we found rodents used L. maackii for cover only on cloudless nights, indicating that the effect of honeysuckle was weather-dependent. Our work provides experimental evidence that this invasive plant species changes habitat characteristics, and in so doing alters the behavior of small- and medium-sized mammals. Changes in seed predator behavior may lead to cascading effects on the seeds that mice consume.

Plant neighbour identity matters to belowground interactions under controlled conditions.

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Armas, Cristina; Pugnaire, Francisco Ignacio

2011-01-01

Root competition is an almost ubiquitous feature of plant communities with profound effects on their structure and composition. Far beyond the traditional view that plants interact mainly through resource depletion (exploitation competition), roots are known to be able to interact with their environment using a large variety of mechanisms that may inhibit or enhance access of other roots to the resource or affect plant growth (contest interactions). However, an extensive analysis on how these contest root interactions may affect species interaction abilities is almost lacking. In a common garden experiment with ten perennial plant species we forced pairs of plants of the same or different species to overlap their roots and analyzed how belowground contest interactions affected plant performance, biomass allocation patterns, and competitive abilities under abundant resource supply. Our results showed that net interaction outcome ranged from negative to positive, affecting total plant mass and allocation patterns. A species could be a strong competitor against one species, weaker against another one, and even facilitator to a third species. This leads to sets of species where competitive hierarchies may be clear but also to groups where such rankings are not, suggesting that intransitive root interactions may be crucial for species coexistence. The outcome of belowground contest interactions is strongly dependent on neighbours' identity. In natural plant communities this conditional outcome may hypothetically help species to interact in non-hierarchical and intransitive networks, which in turn might promote coexistence.

Coexistence via resource partitioning fails to generate an increase in community function.

Directory of Open Access Journals (Sweden)

John P DeLong

Full Text Available Classic ecological theory suggests that resource partitioning facilitates the coexistence of species by reducing inter-specific competition. A byproduct of this process is an increase in overall community function, because a greater spectrum of resources can be used. In contrast, coexistence facilitated by neutral mechanisms is not expected to increase function. We studied coexistence in laboratory microcosms of the bactivorous ciliates Paramecium aurelia and Colpidium striatum to understand the relationship between function and coexistence mechanism. We quantified population and community-level function (biomass and oxygen consumption, competitive interactions, and resource partitioning. The two ciliates partitioned their bacterial resource along a size axis, with the larger ciliate consuming larger bacteria than the smaller ciliate. Despite this, there was no gain in function at the community level for either biomass or oxygen consumption, and competitive effects were symmetrical within and between species. Because other potential coexistence mechanisms can be ruled out, it is likely that inter-specific interference competition diminished the expected gain in function generated by resource partitioning, leading to a system that appeared competitively neutral even when structured by niche partitioning. We also analyzed several previous studies where two species of protists coexisted and found that the two-species communities showed a broad range of biomass levels relative to the single-species states.

Chemical similarity and local community assembly in the species rich tropical genus Piper.

Science.gov (United States)

Salazar, Diego; Jaramillo, M Alejandra; Marquis, Robert J

2016-11-01

Community ecologists have strived to find mechanisms that mediate the assembly of natural communities. Recent evidence suggests that natural enemies could play an important role in the assembly of hyper-diverse tropical plant systems. Classic ecological theory predicts that in order for coexistence to occur, species differences must be maximized across biologically important niche dimensions. For plant-herbivore interactions, it has been recently suggested that, within a particular community, plant species that maximize the difference in chemical defense profiles compared to neighboring taxa will have a relative competitive advantage. Here we tested the hypothesis that plant chemical diversity can affect local community composition in the hyper-diverse genus Piper at a lowland wet forest location in Costa Rica. We first characterized the chemical composition of 27 of the most locally abundant species of Piper. We then tested whether species with different chemical compositions were more likely to coexist. Finally, we assessed the degree to which Piper phylogenetic relationships are related to differences in secondary chemical composition and community assembly. We found that, on average, co-occurring species were more likely to differ in chemical composition than expected by chance. Contrary to expectations, there was no phylogenetic signal for overall secondary chemical composition. In addition we found that species in local communities were, on average, more phylogenetically closely related than expected by chance, suggesting that functional traits other than those measured here also influence local assembly. We propose that selection by herbivores for divergent chemistries between closely related species facilitates the coexistence of a high diversity of congeneric taxa via apparent competition. © 2016 by the Ecological Society of America.

BAAD: a biomass and allometry database for woody plants

Science.gov (United States)

Daniel S. Falster; Remko A. Duursma; Masae I. Ishihara; Diego R. Barneche; Richard G. FitzJohn; Angelica Varhammar; Masahiro Aiba; Makoto Ando; Niels Anten; Michael J. Aspinwall; Jennifer L. Baltzer; Christopher Baraloto; Michael Battaglia; John J. Battles; Ben Bond-Lamberty; Michiel van Breugel; Yves Claveau; Masako Dannoura; Sylvain Delagrange; Jean-Christophe Domec; Farrah Fatemi; Wang Feng; Veronica Gargaglione; Yoshiaki Goto; Akio Hagihara; Jefferson S. Hall; Steve Hamilton; Degi Harja; Tsutom Hiura; Robert Holdaway; Lindsay S. Hutley; Tomoaki Ichie; Eric J. Jokela; Anu Kantola; Jeff W. G. Kelly; Tanaka Kenzo; David King; Brian D. Kloeppel; Takashi Kohyama; Akira Komiyama; Jean-Paul Laclau; Christopher H. Lusk; Douglas A. Maguire; Guerric Le Maire; Ammikki Makela; Lars Markesteijn; John Marshall; Katherine McCulloh; Itsuo Miyata; Karel Mokany; Shugeta Mori; Randall W. Myster; Masahiro Nagano; Shawna L. Naidu; Yann Nouvellon; Anthony P. O' Grady; Kevin L. O' Hara; Toshiyuki Ohtsuka; Noriyuki Osada; Olusegun O. Osunkoya; Pablo Luis Peri; Any Mary Petritan; Lourens Poorter; Angelika Portsmuth; Catherine Potvin; Johannes Ransijn; Douglas Reid; Sabina C. Ribeiro; Scott D. Roberts; Rolando Rodriguez; Angela Saldana-Acosta; Ignacio Santa-Regina; Kaichiro Sasa; N. Galia Selaya; Stephen C. Sillett; Frank Sterck; Kentaro Takagi; Takeshi Tange; Hiroyuki Tanouchi; David Tissue; Toru Umehara; Matthew A. Vadeboncoeur; Fernando Valladares; Petteri Vanninen; Jian R. Wang; Elizabeth Wenk; Richard Williams; Fabiano de Aquino Ximenes; Atsushi Yamaba; Toshihiro Yamada; Takuo Yamakura; Ruth D. Yanai; Robert A. York

2015-01-01

Understanding how plants are constructed—i.e., how key size dimensions and the amount of mass invested in different tissues varies among individuals—is essential for modeling plant growth, carbon stocks, and energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting species and among species adapted to...

Phylogenetic constrains on mycorrhizal specificity in eight Dendrobium (Orchidaceae) species.

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Xing, Xiaoke; Ma, Xueting; Men, Jinxin; Chen, Yanhong; Guo, Shunxing

2017-05-01

Plant phylogeny constrains orchid mycorrhizal (OrM) fungal community composition in some orchids. Here, we investigated the structures of the OrM fungal communities of eight Dendrobium species in one niche to determine whether similarities in the OrM fungal communities correlated with the phylogeny of the host plants and whether the Dendrobium-OrM fungal interactions are phylogenetically conserved. A phylogeny based on DNA data was constructed for the eight coexisting Dendrobium species, and the OrM fungal communities were characterized by their roots. There were 31 different fungal lineages associated with the eight Dendrobium species. In total, 82.98% of the identified associations belonging to Tulasnellaceae, and a smaller proportion involved members of the unknown Basidiomycota (9.67%). Community analyses revealed that phylogenetically related Dendrobium tended to interact with a similar set of Tulasnellaceae fungi. The interactions between Dendrobium and Tulasnellaceae fungi were significantly influenced by the phylogenetic relationships among the Dendrobium species. Our results provide evidence that the mycorrhizal specificity in the eight coexisting Dendrobium species was phylogenetically conserved.

Ecophysiological adaptations of coexisting Sphagnum mosses

OpenAIRE

HÁJEK, Tomáš

2008-01-01

I studied ecological and physiological adaptations of peat misses (Sphagnum species) coexisting along the environmental gradients in mires. Production, decomposition, water relations, desiccation tolerance and nutrient economy of Sphagnum species were evaluates along the hummock-hollow gradient of water table, while the light adaptations were assessed in an open and forested mire

Important biological factors for utilizing native plant species

Science.gov (United States)

Loren E. Wiesner

1999-01-01

Native plant species are valuable resources for revegetation of disturbed ecosystems. The success of these plantings is dependent on the native species selected, quality of seed used, condition of the soil, environmental conditions before and after planting, planting equipment used, time of planting, and other factors. Most native species contain dormant seed. Dormancy...

Identification of invasive and expansive plant species based on airborne hyperspectral and ALS data

Science.gov (United States)

Szporak-Wasilewska, Sylwia; Kuc, Gabriela; Jóźwiak, Jacek; Demarchi, Luca; Chormański, Jarosław; Marcinkowska-Ochtyra, Adriana; Ochtyra, Adrian; Jarocińska, Anna; Sabat, Anita; Zagajewski, Bogdan; Tokarska-Guzik, Barbara; Bzdęga, Katarzyna; Pasierbiński, Andrzej; Fojcik, Barbara; Jędrzejczyk-Korycińska, Monika; Kopeć, Dominik; Wylazłowska, Justyna; Woziwoda, Beata; Michalska-Hejduk, Dorota; Halladin-Dąbrowska, Anna

2017-04-01

. Simultaneously to airborne data acquisitions also botanical surveys were performed covering in total 5680 reference plots for 18 alien invasive and native expansive plant species (1886 in first flight campaign, 1907 in second and 1887 in third). The collected data were used to identify species characteristics such as spectral properties among others (percentage cover, growth stage, discoloration, coexisting species, land use, plant litter). The research includes 10 invasive alien species and 8 native expansive plant species. Amongst plant species selected for the purposes of this study were: Robinia pseudoacacia, Padus serotina, Rumex confertus, Erigeron annuus, Spiraea tomentosa, Solidago spp., Lupinus polyphyllus, Reynoutria spp., Echinocystis lobata and Heracleum spp. as alien invasive species, and Urtica dioica, Filipendula ulmaria, Phragmites australis, Rubus spp, Calamagrostis epigejos, Cirsium arvense, Molinia caerulea, Deschampsia caespitosa as native expansive species. In this study we present the methodology used for identification of invasive alien and expansive native plant species using hyperspectral and airborne laser data with resulting accuracies using different classification methods and exemplary distribution maps. The research within this study will be continued during growing season of the year 2017. Acknowledgements This research has been carried out under the Biostrateg Programme of the Polish National Centre for Research and Development (NCBiR), project No.: DZP/BIOSTRATEG-II/390/2015: The innovative approach supporting monitoring of non-forest Natura 2000 habitats, using remote sensing methods (HabitARS).

Differences in Water-use Strategies Along an Aridity Gradient Between Two Coexisting Desert Shrubs (Reaumuria soongorica and Nitraria sphaerocarpa): Isotopic Approaches with Physiological Evidence

Science.gov (United States)

Zhang, C.; Li, X.; Huawu, W.; Wang, P.; Wang, Y.; WU, X.; Li, W.; Huang, Y.

2017-12-01

Understanding of the responses of different plant species to changes in available water source is critical for accurately modeling and predicting species dynamic and the effect of expected climate change on plant distribution. Our study aimed to explore whether there were differences of water use strategies between the two coexisting shrubs (Reaumuria songarica Maxim and Nitraria.sphaerocarpa Maxim ) in response to different amounts of summer precipitation. We conducted a 3-year field observations at three sites along a gradient of precipitation from middle to lower reaches of Heihe River basin (HRB), northwestern China. Stable oxygen composition (δ18O) in plant xylem water, soil water, and groundwater were analyzed concurrently with ecophysiological measurement at monthly intervals during the growing seasons. The results showed that both R. soongorica and N. sphaerocarpa growing in regions with precipitation dominated water supply exhibited distinct seasonal pattern in water source utilization. In contrast, R. soongorica in the most arid site has the consistent water-use strategy relying primarily on groundwater sources regardless seasonality of precipitation. Water source for coexisting R. soongorica and N. sphaerocarpa did not differ at the sites where precipitation amount was high, but they were a significant different in more arid locations. N. sphaerocarpa is more sensitive to summer precipitation than R. soongorica in terms of predawn water potential (Ψpd), stomatal conductance and foliage δ13C. Our findings reveal that plant relying groundwater sources could maintain a consistent water use strategies, but did not for plants took up precipitation-derived water source. Our results demonstrated that N. sphaerocarpa with a shallower rooting system was more responsive for summer rainfall than did for R. soongorica. We also found that the difference in water source uptake between the coexisting species was more apparent in more arid locations. Results of this

Why some plant species are rare.

Science.gov (United States)

Wieger Wamelink, G W; Wamelink, G W Weiger; Goedhart, Paul W; Frissel, Joep; Frissel, Josep Y

2014-01-01

Biodiversity, including plant species diversity, is threatened worldwide as a result of anthropogenic pressures such as an increase of pollutants and climate change. Rare species in particular are on the verge of becoming extinct. It is still unclear as to why some plant species are rare and others are not. Are they rare due to: intrinsic reasons, dispersal capacity, the effects of management or abiotic circumstances? Habitat preference of rare plant species may play an important role in determining why some species are rare. Based on an extensive data set of soil parameters we investigated if rarity is due to a narrow habitat preference for abiotic soil parameters. For 23 different abiotic soil parameters, of which the most influential were groundwater-table, soil-pH and nutrient-contents, we estimated species responses for common and rare species. Based on the responses per species we calculated the range of occurrence, the range between the 5 and 95 percentile of the response curve giving the habitat preference. Subsequently, we calculated the average response range for common and rare species. In addition, we designed a new graphic in order to provide a better means for presentation of the results. The habitat preferences of rare species for abiotic soil conditions are significantly narrower than for common species. Twenty of the twenty-three abiotic parameters showed on average significantly narrower habitat preferences for rare species than for common species; none of the abiotic parameters showed on average a narrower habitat preference for common species. The results have major implications for the conservation of rare plant species; accordingly management and nature development should be focussed on the maintenance and creation of a broad range of environmental conditions, so that the requirements of rare species are met. The conservation of (abiotic) gradients within ecosystems is particularly important for preserving rare species.

Exotic plant species receive adequate pollinator service despite variable integration into plant-pollinator networks.

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Thompson, Amibeth H; Knight, Tiffany M

2018-05-01

Both exotic and native plant species rely on insect pollinators for reproductive success, and yet few studies have evaluated whether and how exotic plant species receive services from native pollinators for successful reproduction in their introduced range. Plant species are expected to successfully reproduce in their exotic range if they have low reliance on animal pollinators or if they successfully integrate themselves into resident plant-pollinator networks. Here, we quantify the breeding system, network integration, and pollen limitation for ten focal exotic plant species in North America. Most exotic plant species relied on animal pollinators for reproduction, and these species varied in their network integration. However, plant reproduction was limited by pollen receipt for only one plant species. Our results demonstrate that even poorly integrated exotic plant species can still have high pollination service and high reproductive success. The comprehensive framework considered here provides a method to consider the contribution of plant breeding systems and the pollinator community to pollen limitation, and can be applied to future studies to provide a more synthetic understanding of the factors that determine reproductive success of exotic plant species.

No universal scale-dependent impacts of invasive species on native plant species richness.

Science.gov (United States)

Stohlgren, Thomas J; Rejmánek, Marcel

2014-01-01

A growing number of studies seeking generalizations about the impact of plant invasions compare heavily invaded sites to uninvaded sites. But does this approach warrant any generalizations? Using two large datasets from forests, grasslands and desert ecosystems across the conterminous United States, we show that (i) a continuum of invasion impacts exists in many biomes and (ii) many possible species-area relationships may emerge reflecting a wide range of patterns of co-occurrence of native and alien plant species. Our results contradict a smaller recent study by Powell et al. 2013 (Science 339, 316-318. (doi:10.1126/science.1226817)), who compared heavily invaded and uninvaded sites in three biomes and concluded that plant communities invaded by non-native plant species generally have lower local richness (intercepts of log species richness-log area regression lines) but steeper species accumulation with increasing area (slopes of the regression lines) than do uninvaded communities. We conclude that the impacts of plant invasions on plant species richness are not universal.

Do species differ in their ability to coexist with the dominant alien Lupinus polyphyllus? A comparison between two distinct invaded ranges and a native range

Directory of Open Access Journals (Sweden)

Martin Hejda

2013-06-01

Full Text Available The community-level impacts of invasive plants are likely to vary depending on the character of native species of the target communities and their ability to thrive within the stands of the dominant alien invader. Therefore, I examined the response of native species richness to the cover of the dominant alien Lupinus polyphyllus in two distinct invaded ranges: Czech Republic (Central Europe and New Zealand. I compared the relation between native species richness and the cover of the dominant alien L. polyphyllus with that in its native range, Pacific Northwest, USA.In the native range, I found no response of native species richness to the cover of L. polyphyllus. In the Czech Republic (central Europe, the richness of native species related to it negativelly, but the relation was only marginally significant. Contrary to that, the richness of species native to New Zealand related to the cover of L. polyphyllus strongly negatively and the negative relation was significantly stronger than that of species native to Europe.Of the two invaded ranges, species native to New Zealand have been documented to be much more vulnerable to the conditions associated with the invasion and dominance of L. polyphyllus, compared to species native to central Europe. This principle has been shown both across these two invaded ranges and in New Zealand, where the aliens of european origin successfully coexist with the dominant invasive alien L. polyphyllus. Similarly, species in the native range of L. polyphyllus showed no relation to its cover, indicating their ability to thrive even in dense stands of this dominant species.

Meaningful traits for grouping plant species across arid ecosystems.

Science.gov (United States)

Bär Lamas, Marlene Ivonne; Carrera, A L; Bertiller, M B

2016-05-01

Grouping species may provide some degree of simplification to understand the ecological function of plants on key ecosystem processes. We asked whether groups of plant species based on morpho-chemical traits associated with plant persistence and stress/disturbance resistance reflect dominant plant growth forms in arid ecosystems. We selected twelve sites across an aridity gradient in northern Patagonia. At each site, we identified modal size plants of each dominant species and assessed specific leaf area (SLA), plant height, seed mass, N and soluble phenol concentration in green and senesced leaves at each plant. Plant species were grouped according with plant growth forms (perennial grasses, evergreen shrubs and deciduous shrubs) and plant morphological and/or chemical traits using cluster analysis. We calculated mean values of each plant trait for each species group and plant growth form. Plant growth forms significantly differed among them in most of the morpho-chemical traits. Evergreen shrubs were tall plants with the highest seed mass and soluble phenols in leaves, deciduous shrubs were also tall plants with high SLA and the highest N in leaves, and perennial grasses were short plants with high SLA and low concentration of N and soluble phenols in leaves. Grouping species by the combination of morpho-chemical traits yielded 4 groups in which species from one growth form prevailed. These species groups differed in soluble phenol concentration in senesced leaves and plant height. These traits were highly correlated. We concluded that (1) plant height is a relevant synthetic variable, (2) growth forms adequately summarize ecological strategies of species in arid ecosystems, and (3) the inclusion of plant morphological and chemical traits related to defenses against environmental stresses and herbivory enhanced the potential of species grouping, particularly within shrubby growth forms.

Competitive exclusion among fig wasps achieved via entrainment of host plant flowering phenology.

Directory of Open Access Journals (Sweden)

Min Liu

Full Text Available Molecular techniques are revealing increasing numbers of morphologically similar but co-existing cryptic species, challenging the niche theory. To understand the co-existence mechanism, we studied phenologies of morphologically similar species of fig wasps that pollinate the creeping fig (F. pumila in eastern China. We compared phenologies of fig wasp emergence and host flowering at sites where one or both pollinators were present. At the site where both pollinators were present, we used sticky traps to capture the emerged fig wasps and identified species identity using mitochondrial DNA COI gene. We also genotyped F. pumila individuals of the three sites using polymorphic microsatellites to detect whether the host populations were differentiated. Male F. pumila produced two major crops annually, with figs receptive in spring and summer. A small partial third crop of receptive figs occurred in the autumn, but few of the second crop figs matured at that time. Hence, few pollinators were available to enter third crop figs and they mostly aborted, resulting in two generations of pollinating wasps each year, plus a partial third generation. Receptive figs were produced on male plants in spring and summer, timed to coincide with the release of short-lived adult pollinators from the same individual plants. Most plants were pollinated by a single species. Plants pollinated by Wiebesia sp. 1 released wasps earlier than those pollinated by Wiebesia sp. 3, with little overlap. Plants occupied by different pollinators were not spatially separated, nor genetically distinct. Our findings show that these differences created mismatches with the flight periods of the other Wiebesia species, largely 'reserving' individual plants for the resident pollinator species. This pre-emptive competitive displacement may prevent long term co-existence of the two pollinators.

Do Epigeal Termite Mounds Increase the Diversity of Plant Habitats in a Tropical Rain Forest in Peninsular Malaysia?

Science.gov (United States)

Beaudrot, Lydia; Du, Yanjun; Rahman Kassim, Abdul; Rejmánek, Marcel; Harrison, Rhett D.

2011-01-01

The extent to which environmental heterogeneity can account for tree species coexistence in diverse ecosystems, such as tropical rainforests, is hotly debated, although the importance of spatial variability in contributing to species co-existence is well recognized. Termites contribute to the micro-topographical and nutrient spatial heterogeneity of tropical forests. We therefore investigated whether epigeal termite mounds could contribute to the coexistence of plant species within a 50 ha plot at Pasoh Forest Reserve, Malaysia. Overall, stem density was significantly higher on mounds than in their immediate surroundings, but tree species diversity was significantly lower. Canonical correspondence analysis showed that location on or off mounds significantly influenced species distribution when stems were characterized by basal area. Like studies of termite mounds in other ecosystems, our results suggest that epigeal termite mounds provide a specific microhabitat for the enhanced growth and survival of certain species in these species-rich tropical forests. However, the extent to which epigeal termite mounds facilitate species coexistence warrants further investigation. PMID:21625558

INVENTORY OF THE INVASIVE ALIE N PLANT SPECIES IN INDONESIA

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SRI S UDARMIYATI T JITROSOEDIRDJO

2005-01-01

Full Text Available An inventory of the alien plant species in Indone sia based on the existing references and herbarium specimens concluded that 1936 alien plant species ar e found in Indonesia which belong to 187 families. Field studies should be done to get the complete figur es of alien plant species in Indonesia. Based on the existing figures of the plant species, the invasive alien plant species can be iden tified, followed by studies on the assessment of losses, biology, management and their possible utilizations. Alien plant species are imported to Indonesia for cultivation, collection of the botanical garden, as experimental plants or other curiosities. Aside from plants purposely imported, there are also introduced plant propagules conta-minating imported agricultural products. These alien plant species can be beneficial or have a potential of being invasive. The alien cultivated species consisted of 67% of the total number. More than half of the cultivated plants are ornamental plants. Some of th e species are naturalized or escaped from cultivation and become wild and invasive. Some other natura lized species, adapted well without any problems of invasion. There are 339 species or 17% of the species r ecorded as weeds. The highest record of weeds is found in the family of Poaceae (57 species, follo wed by Asteraceae (53 species and Cyperaceae (35 species. There are 6 families having more than 10 species of weeds: Amaranthaceae, Asteraceae, Cyperaceae, Euphorbiaceae, Poaceae, and Rubiaceae. Three families have more than 100 species: Asteraceae 162 species, Poaceae 120 species, and Papillionaceae 103 species. Five species of aquatic and 20 species of terrestrial plants considered as important alien plant species in Indonesia were identified and some of their distributions noted

Coexistence of a General Elliptic System in Population Dynamics

DEFF Research Database (Denmark)

Pedersen, Michael

2004-01-01

This paper is concerned with a strongly-coupled elliptic system representing a competitive interaction between two species. We give a sufficient condition for the existence of positive solutions. An example is also given to show that there is a coexistence of a steady state if the cross-diffusion......This paper is concerned with a strongly-coupled elliptic system representing a competitive interaction between two species. We give a sufficient condition for the existence of positive solutions. An example is also given to show that there is a coexistence of a steady state if the cross...

Inventory of the Invasive Alien Plant Species in Indonesia

OpenAIRE

TJITROSOEDIRDJO, SRI SUDARMIYATI

2005-01-01

An inventory of the alien plant species in Indonesia based on the existing references and herbarium specimens concluded that 1936 alien plant species are found in Indonesia which belong to 187 families. Field studies should be done to get the complete figures of alien plant species in Indonesia. Based on the existing figures of the plant species, the invasive alien plant species can be identified, followed by studies on the assessment of losses, biology, management and their possible utilizat...

Do invasive plant species alter soil health?

Science.gov (United States)

Invasive species may alter soil characteristics or interact with the soil microbial community to yield a competitive advantage. Our objectives were to determine: if invasive plant species alter soil properties important to soil health; and the long-term effects of invasive plant species on soil pro...

Species interactions and plant polyploidy.

Science.gov (United States)

Segraves, Kari A; Anneberg, Thomas J

2016-07-01

Polyploidy is a common mode of speciation that can have far-reaching consequences for plant ecology and evolution. Because polyploidy can induce an array of phenotypic changes, there can be cascading effects on interactions with other species. These interactions, in turn, can have reciprocal effects on polyploid plants, potentially impacting their establishment and persistence. Although there is a wealth of information on the genetic and phenotypic effects of polyploidy, the study of species interactions in polyploid plants remains a comparatively young field. Here we reviewed the available evidence for how polyploidy may impact many types of species interactions that range from mutualism to antagonism. Specifically, we focused on three main questions: (1) Does polyploidy directly cause the formation of novel interactions not experienced by diploids, or does it create an opportunity for natural selection to then form novel interactions? (2) Does polyploidy cause consistent, predictable changes in species interactions vs. the evolution of idiosyncratic differences? (3) Does polyploidy lead to greater evolvability in species interactions? From the scarce evidence available, we found that novel interactions are rare but that polyploidy can induce changes in pollinator, herbivore, and pathogen interactions. Although further tests are needed, it is likely that selection following whole-genome duplication is important in all types of species interaction and that there are circumstances in which polyploidy can enhance the evolvability of interactions with other species. © 2016 Botanical Society of America.

Co-existence in multispecies biofilm communities

DEFF Research Database (Denmark)

Røder, Henriette Lyng

of these emergent properties which are relevant to as diverse areas as clinical settings and natural systems. In this thesis, I have attempted to contribute to our knowledge on the multispecies interactions with a special focus on biofilm communities. I was especially interested in how co-existing species affect...... each other and in understanding the key mechanisms and interactions involved. In the introduction of this thesis the most important concepts of multi-species interactions and biofilm development are explained. After this the topic changes to the various ways of examining community interactions...... and production. The analysis was further extended in manuscript 3, in which the effect of social interac-tions on biofilm formation in multispecies co-cultures isolated from a diverse range of environments was examined. The question raised was whether the interspecific interactions of co-existing bacteria...

[Psychoactive plant species--actual list of plants prohibited in Poland].

Science.gov (United States)

Simonienko, Katarzyna; Waszkiewicz, Napoleon; Szulc, Agata

2013-01-01

According to the Act on Counteracting Drug Addiction (20-th of March, 2009, Dz. U. Nr 63 poz. 520.) the list of federally prohibited plants in Poland was expanded to include 16 new species. Until that time the only illegal plant materials were cannabis, papaver, coca and most of their products. The actual list of herbal narcotics includes species which significantly influence on the central nervous system work but which are rarely described in the national literature. The plants usually come from distant places, where--among primeval cultures--are used for ritual purposes. In our civilization the plants are usually used experimentally, recreationally or to gain particular narcotic effects. The results of the consumption vary: they can be specific or less typical, imitate other substances intake, mental disorders or different pathological states. The plant active substances can interact with other medicaments, be toxic to internal organs, cause serious threat to health or even death. This article describes the sixteen plant species, which are now prohibited in Poland, their biochemical ingredients and their influence on the human organism.

The Invasive Plant Species Education Guide

Science.gov (United States)

Mason, Kevin; James, Krista; Carlson, Kitrina; D'Angelo, Jean

2010-01-01

To help high school students gain a solid understanding of invasive plant species, university faculty and students from the University of Wisconsin-Stout (UW-Stout) and a local high school teacher worked together to develop the Invasive Plant Species (IPS) Education Guide. The IPS Education Guide includes nine lessons that give students an…

Phylogenetically poor plant communities receive more alien species, which more easily coexist with natives

NARCIS (Netherlands)

Gerhold, P.; Pärtel, M.; Tackenberg, O.; Hennekens, S.M.; Bartish, I.; Schaminee, J.H.J.; Fergus, A.J.F.; Ozinga, W.A.; Prinzing, A.

2011-01-01

Alien species can be a major threat to ecological communities, but we do not know why some community types allow the entry of many more alien species than do others. Here, for the first time, we suggest that evolutionary diversity inherent to the constituent species of a community may determine its

Intraspecific density dependence and a guild of consumers coexisting on one resource.

Science.gov (United States)

McPeek, Mark A

2012-12-01

The importance of negative intraspecific density dependence to promoting species coexistence in a community is well accepted. However, such mechanisms are typically omitted from more explicit models of community dynamics. Here I analyze a variation of the Rosenzweig-MacArthur consumer-resource model that includes negative intraspecific density dependence for consumers to explore its effect on the coexistence of multiple consumers feeding on a single resource. This analysis demonstrates that a guild of multiple consumers can easily coexist on a single resource if each limits its own abundance to some degree, and stronger intraspecific density dependence permits a wider variety of consumers to coexist. The mechanism permitting multiple consumers to coexist works in a fashion similar to apparent competition or to each consumer having its own specialized predator. These results argue for a more explicit emphasis on how negative intraspecific density dependence is generated and how these mechanisms combine with species interactions to shape overall community structure.

Mechanical branch constraints contribute to life-history variation across tree species in a Bolivian forest.

NARCIS (Netherlands)

Sterck, F.J.; Gelder, van H.A.; Poorter, L.

2006-01-01

1 Trade-offs among plant traits may contribute to specialization for different environments and coexistence of plant species. This may be the first study that shows how trade-offs among branch traits contribute to variation in crown size, light requirements and maximum height across multiple

Dynamic preferential allocation to arbuscular mycorrhizal fungi explains fungal succession and coexistence.

Science.gov (United States)

Bachelot, Benedicte; Lee, Charlotte T

2018-02-01

Evidence accumulates about the role of arbuscular mycorrhizal (AM) fungi in shaping plant communities, but little is known about the factors determining the biomass and coexistence of several types of AM fungi in a plant community. Here, using a consumer-resource framework that treats the relationship between plants and fungi as simultaneous, reciprocal exploitation, we investigated what patterns of dynamic preferential plant carbon allocation to empirically-defined fungal types (on-going partner choice) would be optimal for plants, and how these patterns depend on successional dynamics. We found that ruderal AM fungi can dominate under low steady-state nutrient availability, and competitor AM fungi can dominate at higher steady-state nutrient availability; these are conditions characteristic of early and late succession, respectively. We also found that dynamic preferential allocation alone can maintain a diversity of mutualists, suggesting that on-going partner choice is a new coexistence mechanism for mutualists. Our model can therefore explain both mutualist coexistence and successional strategy, providing a powerful tool to derive testable predictions. © 2017 by the Ecological Society of America.

Invasive plant species in hardwood tree plantations

Science.gov (United States)

Rochelle R. Beasley; Paula M. Pijut

2010-01-01

Invasive plants are species that can grow and spread aggressively, mature quickly, and invade an ecosystem causing economic and environmental damage. Invasive plants usually invade disturbed areas, but can also colonize small areas quickly, and may spread and dominate large areas in a few short years. Invasive plant species displace native or desirable forest...

Germination and early plant development of ten plant species ...

Science.gov (United States)

Ten agronomic plant species were exposed to different concentrations of nano titanium dioxide (nTiO2) or nano cerium oxide (nCeO2) (0, 250, 500 and 1000 mg/L) to examine potential effects on germination and early seedling development. We modified a standard test protocol developed for soluble chemicals (OPPTS 850.4200) to determine if such an approach might be useful for screening engineered nanomaterials (ENMs) and whether there were differences in response across a range of commercially important plant species to two common metal oxide ENMs. Eight of 10 species responded to nTiO2, and 5 species responded to nCeO2. Overall, it appeared that early root growth may be a more sensitive indicator of potential effects from ENM exposure than germination. The observed effects did not always relate to the exposure concentration, indicating that mass-based concentration may not fully explain developmental effects of these two ENMs. The results suggest that nTiO2 and nCeO2 have different effects on early plant growth of agronomic species, which may alter the timing of specific developmental events during their life cycle. In addition, standard germination tests, which are commonly used for toxicity screening of new materials, may not detect the subtle but potentially more important changes associated with early growth and development in terrestrial plants. Engineered nanoparticles (ENMs) have been recognized as valuable components of new technologies and are current

BIOGEOGRAPHICAL IMPLICATIONS OF SOME PLANT SPECIES FROM A TROPICAL MONTANE RAIN FOREST IN SOUTHERN YUNNAN

Institute of Scientific and Technical Information of China (English)

ZHU Hua

2004-01-01

A pristine montane rain forest was recently discovered from Mengsong of Xishuangbanna in the southern Yunnan.It attracts botanists that many primitive plant taxa across various life forms were co-existed in the montane rain forest.In order to know the biogeography of the montane rain forest,distribution patterns of some species of biogeographical importance from the montane forest were enumerated and their biogeographical implications were discussed with geological explanation.It was concluded that the montane rain forest in the southern Yunnan has strong affinity to montane rain forests in Sumatra or Southeast Asia in broad sense.It was tentatively suggested that Sumatra could be once connected to Myanmar and drifted away due to northward movement of continental Asia by bumping of India plate.

Body size mediated coexistence of consumers competing for resources in space

Science.gov (United States)

Basset, A.; Angelis, D.L.

2007-01-01

Body size is a major phenotypic trait of individuals that commonly differentiates co-occurring species. We analyzed inter-specific competitive interactions between a large consumer and smaller competitors, whose energetics, selection and giving-up behaviour on identical resource patches scaled with individual body size. The aim was to investigate whether pure metabolic constraints on patch behaviour of vagile species can determine coexistence conditions consistent with existing theoretical and experimental evidence. We used an individual-based spatially explicit simulation model at a spatial scale defined by the home range of the large consumer, which was assumed to be parthenogenic and semelparous. Under exploitative conditions, competitive coexistence occurred in a range of body size ratios between 2 and 10. Asymmetrical competition and the mechanism underlying asymmetry, determined by the scaling of energetics and patch behaviour with consumer body size, were the proximate determinant of inter-specific coexistence. The small consumer exploited patches more efficiently, but searched for profitable patches less effectively than the larger competitor. Therefore, body-size related constraints induced niche partitioning, allowing competitive coexistence within a set of conditions where the large consumer maintained control over the small consumer and resource dynamics. The model summarises and extends the existing evidence of species coexistence on a limiting resource, and provides a mechanistic explanation for decoding the size-abundance distribution patterns commonly observed at guild and community levels. ?? Oikos.

Biogeochemical and Ecomorphological Niche Segregation of Mediterranean Woody Species along a Local Gradient

OpenAIRE

Enrique G. de la Riva; Enrique G. de la Riva; Teodoro Marañón; Cyrille Violle; Rafael Villar; Ignacio M. Pérez-Ramos

2017-01-01

According with niche theory the species are specialized in different ecological niches, being able to coexist as result of a differential use of resources. In this context, the biogeochemical niche hypothesis proposes that species have an optimal elemental composition which results from the link between the chemical and morphological traits for the optimum plant functioning. Thus, and attending to the limiting similarity concept, different elemental composition and plant structure among co-oc...

Multiple factors contribute to reproductive isolation between two co-existing Habenaria species (Orchidaceae.

Directory of Open Access Journals (Sweden)

Wenliu Zhang

Full Text Available Reproductive isolation is a key feature that forms barriers to gene flow between distinct plants. In orchids, prezygotic reproductive isolation has been considered to be strong, because their associations with highly specific pollinators. In this study, the reproductive ecology and reproductive isolation of two sympatric Habenaria species, H. davidii and H. fordii, was investigated by floral phenology and morphology, hand-pollination experiments and visitor observation in southwest China. The two species were dependent on insects for pollination and completely self-compatible. A number of factors have been identified to limit gene flow between the two species and achieved full reproductive isolation. Ecogeographic isolation was a weak barrier. H. fordii and H. davidii had completely overlapped flowering periods, and floral morphology plays an important role in floral isolation. The two species shared the same hawkmoth pollinator, Cechenena lineosa, but the pollinaria of the two orchids were attached on different body parts of pollinators. Prezygotic isolation was not complete, but the interspecific pollination treatments of each species resulted in no seed sets, indicating that unlike many other orchid species, in which the postzygotic reproductive isolation is very weak or complete absence, the post-zygotic isolation strongly acted in the stage of seed production between two species. The results illustrate the reproductive isolation between two species involves multiple plant life-history stages and a variety of reproductive barriers can contribute to overall isolation.

Plants on the move: plant-soil interactions in poleward shifting plant species

NARCIS (Netherlands)

Grunsven, van R.H.A.

2008-01-01

As a result of recent global climate change, areas that have previously been climatically unsuitable for species have now become suitable new habitats. Many plant-species are expanding their range polewards, colonizing these newly available areas. If these species are able to expand their range

Genetic diversity within a dominant plant outweighs plant species diversity in structuring an arthropod community.

Science.gov (United States)

Crawford, Kerri M; Rudgers, Jennifer A

2013-05-01

Plant biodiversity is being lost at a rapid rate. This has spurred much interest in elucidating the consequences of this loss for higher trophic levels. Experimental tests have shown that both plant species diversity and genetic diversity within a plant species can influence arthropod community structure. However, the majority of these studies have been conducted in separate systems, so their relative importance is currently unresolved. Furthermore, potential interactions between the two levels of diversity, which likely occur in natural systems, have not been investigated. To clarify these issues, we conducted three experiments in a freshwater sand dune ecosystem. We (1) independently manipulated plant species diversity, (2) independently manipulated genetic diversity within the dominant plant species, Ammophila breviligulata, and (3) jointly manipulated genetic diversity within the dominant plant and species diversity. We found that genetic diversity within the dominant plant species, Ammophila breviligulata, more strongly influenced arthropod communities than plant species diversity, but this effect was dependent on the presence of other species. In species mixtures, A. breviligulata genetic diversity altered overall arthropod community composition, and arthropod richness and abundance peaked at the highest level of genetic diversity. Positive nonadditive effects of diversity were detected, suggesting that arthropods respond to emergent properties of diverse plant communities. However, in the independent manipulations where A. breviligulata was alone, effects of genetic diversity were weaker, with only arthropod richness responding. In contrast, plant species diversity only influenced arthropods when A. breviligulata was absent, and then only influenced herbivore abundance. In addition to showing that genetic diversity within a dominant plant species can have large effects on arthropod community composition, these results suggest that understanding how species

[Species diversity of ex-situ cultivated Chinese medicinal plants].

Science.gov (United States)

Que, Ling; Chi, Xiu-Lian; Zang, Chun-Xin; Zhang, Yu; Chen, Min; Yang, Guang; Jin, An-Qi

2018-03-01

Ex-situ conservation is an important means to protect biological genetic resources. Resource protection has received more and more attention with the continuous improvement of the comprehensive utilization of traditional Chinese medicine resources. In this paper, the research and compilation of the species list of ex-situ cultivated medicinal plants in 12 Chinese Academy of Sciences botanic gardens and 19 specialized medicinal botanic gardens in China were carried out. Based on the Species 2000(2017) and other classification databases, species diversity of medicinal plants ex-situ cultivated in these botanical gardens were analyzed. The study found that there were 16 351 higher plant species in our country, belonging to 276 families and 1 936 genera. Of these, 6 949 specieswere medicinal plants, accounting for 50.4% of the total medicinal plants. There were 1 280 medicinal plants were in threatened status, accounting for 19.6% of all threatened species in the Chinese Biodiversity Red List, with ex-situ cultivated proportion of 59.5%. And 3 988 medicinal plants were Chinese endemic species, accounting for 22.5% of all Chinese endemic species, with ex-situ cultivated proportion of 53.3%. This article has reference significance for the management and protection of medicinal plant resources. Copyright© by the Chinese Pharmaceutical Association.

Trait assembly of woody plants in communities across sub-alpine gradients: Identifying the role of limiting similarity

NARCIS (Netherlands)

Yan, B.; Zhang, J.; Liu, Y.; Li, Z.; Huang, X.; Yang, W.; Prinzing, A.

2012-01-01

Questions - Plant species can be assembled into communities through habitat filtering or species competition, but their relative roles are still debated. We do not know whether there is limited similarity between co-existing species when accounting for the parallel effect of abiotic habitat

Similarity law for Widom lines and coexistence lines.

Science.gov (United States)

Banuti, D T; Raju, M; Ihme, M

2017-05-01

The coexistence line of a fluid separates liquid and gaseous states at subcritical pressures, ending at the critical point. Only recently, it became clear that the supercritical state space can likewise be divided into regions with liquidlike and gaslike properties, separated by an extension to the coexistence line. This crossover line is commonly referred to as the Widom line, and is characterized by large changes in density or enthalpy, manifesting as maxima in the thermodynamic response functions. Thus, a reliable representation of the coexistence line and the Widom line is important for sub- and supercritical applications that depend on an accurate prediction of fluid properties. While it is known for subcritical pressures that nondimensionalization with the respective species critical pressures p_{cr} and temperatures T_{cr} only collapses coexistence line data for simple fluids, this approach is used for Widom lines of all fluids. However, we show here that the Widom line does not adhere to the corresponding states principle, but instead to the extended corresponding states principle. We resolve this problem in two steps. First, we propose a Widom line functional based on the Clapeyron equation and derive an analytical, species specific expression for the only parameter from the Soave-Redlich-Kwong equation of state. This parameter is a function of the acentric factor ω and compares well with experimental data. Second, we introduce the scaled reduced pressure p_{r}^{*} to replace the previously used reduced pressure p_{r}=p/p_{cr}. We show that p_{r}^{*} is a function of the acentric factor only and can thus be readily determined from fluid property tables. It collapses both subcritical coexistence line and supercritical Widom line data over a wide range of species with acentric factors ranging from -0.38 (helium) to 0.34 (water), including alkanes up to n-hexane. By using p_{r}^{*}, the extended corresponding states principle can be applied within

Hydraulic lift and tolerance to salinity of semiarid species: consequences for species interactions.

Science.gov (United States)

Armas, Cristina; Padilla, Francisco M; Pugnaire, Francisco I; Jackson, Robert B

2010-01-01

The different abilities of plant species to use ephemeral or permanent water sources strongly affect physiological performance and species coexistence in water-limited ecosystems. In addition to withstanding drought, plants in coastal habitats often have to withstand highly saline soils, an additional ecological stress. Here we tested whether observed competitive abilities and C-water relations of two interacting shrub species from an arid coastal system were more related to differences in root architecture or salinity tolerance. We explored water sources of interacting Juniperus phoenicea Guss. and Pistacia lentiscus L. plants by conducting physiology measurements, including water relations, CO2 exchange, photochemical efficiency, sap osmolality, and water and C isotopes. We also conducted parallel soil analyses that included electrical conductivity, humidity, and water isotopes. During drought, Pistacia shrubs relied primarily on permanent salty groundwater, while isolated Juniperus plants took up the scarce and relatively fresh water stored in upper soil layers. As drought progressed further, the physiological activity of Juniperus plants nearly stopped while Pistacia plants were only slightly affected. Juniperus plants growing with Pistacia had stem-water isotopes that matched Pistacia, unlike values for isolated Juniperus plants. This result suggests that Pistacia shrubs supplied water to nearby Juniperus plants through hydraulic lift. This lifted water, however, did not appear to benefit Juniperus plants, as their physiological performance with co-occurring Pistacia plants was poor, including lower water potentials and rates of photosynthesis than isolated plants. Juniperus was more salt sensitive than Pistacia, which withstood salinity levels similar to that of groundwater. Overall, the different abilities of the two species to use salty water appear to drive the outcome of their interaction, resulting in asymmetric competition where Juniperus is negatively

Community structure informs species geographic distributions

KAUST Repository

Montesinos-Navarro, Alicia

2018-05-23

Understanding what determines species\\' geographic distributions is crucial for assessing global change threats to biodiversity. Measuring limits on distributions is usually, and necessarily, done with data at large geographic extents and coarse spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. \\'community structure\\') reflects assembly processes occurring at small scales, and are often available for relatively extensive areas, so could be useful for explaining species distributions. We demonstrate that Bayesian Network Inference (BNI) can overcome several challenges to including community structure into studies of species distributions, despite having been little used to date. We hypothesized that the relative abundance of coexisting species can improve predictions of species distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to incorporate community structure into Species Distribution Models (SDMs), alongside environmental information. Information on species associations improved SDM predictions of community structure and species distributions moderately, though for some habitat specialists the deviance explained increased by up to 15%. We demonstrate that most species associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a proxy for local ecological processes. Our study shows that Bayesian Networks, when interpreted carefully, can be used to include local conditions into measurements of species\\' large-scale distributions, and this information can improve the predictions of species distributions.

A Plumber's-Eye View of Xylem Water Transport in Woody Plants

Science.gov (United States)

Martinez-Vilalta, Jordi; Pinol, Josep

2004-01-01

We present a practical for university-level students aimed at measuring and comparing xylem hydraulic properties of co-existing plant species. After sampling branches of several woody species in the field, their main hydraulic properties were measured using a simple set-up. Hydraulic conductivity ("K[subscript h]") was calculated as the ratio…

Phytotoxic studies of medicinal plant species of Pakistan

International Nuclear Information System (INIS)

Gilani, S.A.; Adnan, M.; Kikuchi, A.; Fujii, Y.; Shinwari, Z.K.; Kazuo, N.; Watanabe, K.N.

2010-01-01

Allelopathic screening of 81 medicinal plant species, collected from North West Frontier Province (NWFP) Pakistan, was carried out to identify significantly higher allelopathic species for future phyto chemical analyses. For this purpose, sandwich method was used to test allelopathic potentials of leaf leachates of these plant species against lettuce seeds (Lactuca sativa L.). Two different concentrations of 10 mg and 50 mg of leaf leachates were used in the study. The radicle and hypocotyl growths were measured and compared with control treatments. It was observed that an endemic species Seriphidium kurramense, Andrachne cordifolia and Rhazya stricta were the stronger phyto toxic plants as compared to the other test species. Based on the current screening, three potential medicinal plants are recommended for future bioassay guided isolation of allelochemicals and for genetic diversity studies. It would also be interesting to see correlation between genetic markers and isolated allelochemicals. (author)

Endangered Species (Plants). LC Science Tracer Bullet.

Science.gov (United States)

Niskern, Diana, Comp.

This guide is intended for those who wish to study the literature dealing with various aspects of endangered plant species. This document includes the following sections, some of which are bibliographies: (1) "Introductions to the Topic"; (2) "Subject Headings" (for endangered species of plants used by the Library of Congress); (3) "General…

Coexistence in neutral theories: interplay of criticality and mild local preferences

International Nuclear Information System (INIS)

Borile, Claudio; Molina-Garcia, Daniel; Muñoz, Miguel A; Maritan, Amos

2015-01-01

Neutral theories have played a crucial and revolutionary role in fields such as population genetics and biogeography. These theories are critical by definition, in the sense that the overall growth rate of each single allele/species/type vanishes. Thus each species in a neutral model sits at the edge between invasion and extinction, allowing for the coexistence of symmetric/neutral types. However, in finite systems, mono-dominated states are ineluctably reached in relatively short times owing to demographic fluctuations, thus leaving us with an unsatisfactory framework to rationalize empirically-observed long-term coexistence. Here, we scrutinize the effect of heterogeneity in quasi-neutral theories, in which there can be a local mild preference for some of the competing species at some sites, even if the overall species symmetry is maintained. As we show here, mild biases at a small fraction of locations suffice to induce overall robust and durable species coexistence, even in regions arbitrarily far apart from the biased locations. This result stems from the long-range nature of the underlying critical bulk dynamics and has a number of implications, for example, in conservation ecology as it suggests that constructing local specific ‘sanctuaries’ for different competing species can result in global enhancement of biodiversity, even in regions arbitrarily distant from the protected refuges. (paper)

Patterns of resource exploitation in four coexisting globeflower fly species ( Chiastocheta sp.)

Science.gov (United States)

Pompanon, François; Pettex, Emeline; Després, Laurence

2006-03-01

Life history and spatio-temporal patterns of resource utilisation were characterised in four Chiastocheta (Diptera: Anthomyiidae) species, whose larvae compete as seed predators on Trollius europaeus fruits. Interspecific co-occurrence was observed in 80% of the resource patches (= Trollius fruits) in the two communities studied. Isolated larvae from all species had a similar food intake, but differed in development time and size at emergence. Different species exhibit contrasting resource exploitation strategies with specific mining patterns and a partial temporal shift. Two species exhibited particularly singular strategies. C. rotundiventris escaped from strong interactions with other species because it was the first species to develop and the only one to exploit the central pith of Trollius fruits. The key role of this species as the main pollinator of the host-plant appears to be a by-product of constraints imposed by occupying a restricted niche. Although the resource is ephemeral due to seed dispersal, C. dentifera, the last species to oviposit, is not disadvantaged because it has a short development time and rapid food intake. The different patterns can partly explain the stability of Chiastocheta communities, but do not prevent competition to occur at high larval densities.

Coexistence of surface and cave amphipods in an ecotone environment

NARCIS (Netherlands)

Luštrik, R.; Turjak, M.; Kralj-Fišer, S.; Fišer, C.

2011-01-01

Interspecific interactions between surface and subterranean species may be a key determinant for species distributions. Until now, the existence of competition (including predation) between these groups has not been tested. To assess the coexistence and potential role of interspecific interactions

Coexistence and Survival in Conservative Lotka-Volterra Networks

Science.gov (United States)

Knebel, Johannes; Krüger, Torben; Weber, Markus F.; Frey, Erwin

2013-04-01

Analyzing coexistence and survival scenarios of Lotka-Volterra (LV) networks in which the total biomass is conserved is of vital importance for the characterization of long-term dynamics of ecological communities. Here, we introduce a classification scheme for coexistence scenarios in these conservative LV models and quantify the extinction process by employing the Pfaffian of the network’s interaction matrix. We illustrate our findings on global stability properties for general systems of four and five species and find a generalized scaling law for the extinction time.

Food Plants of 19 butterflies species (Lepidoptera from Loreto, Peru

Directory of Open Access Journals (Sweden)

Joel Vásquez Bardales

2017-04-01

Full Text Available This work reports the food plants utilized by 19 species of butterflies from Allpahuayo-Mishana Research Center and the Community of San Rafael, Loreto, Peru. We report 23 plant species and one hybrid of angiosperms used by the butterflies. Larval host plants were 21 species and five were adult nectar sources. Two species were both host plant and nectar source: Passiflora coccinea Aubl. and Passiflora edulis Sims. The most frequently used plant families were Solanaceae, Passifloraceae, Fabaceae and Aristolochiaceae.

Coexistence and Habitat Preference of Two Honeyeaters and a Sunbird on Lombok, Indonesia

DEFF Research Database (Denmark)

Carstensen, Daniel Wisbech; Sweeny, Redmond; Ehlers, Bodil

2011-01-01

On the island of Lombok, Indonesia, three nectarivorous birds partially coexist: the two closely related and very similar Lichmera honeyeaters and a sunbird (Cinnyris jugularis). We investigated how these species segregated ecologically in areas where they coexisted by evaluating foraging visits...

Phytophthora Species, New Threats to the Plant Health in Korea

Directory of Open Access Journals (Sweden)

Ik-Hwa Hyun

2014-12-01

Full Text Available Given the lack of a resistant genetic pool in host plants, the introduction of exotic invasive pathogens can result in epidemics that affect a specific ecosystem and economy. Plant quarantine, which is designed to protect endemic plant resources, is a highly invaluable safeguard that should keep biosecurity with increasing international trade and global transportation. A total of 34 species of plant pathogens including Phytophthora infestans were documented as introduced from other countries into Korea from 1900 to 2010. The genus Phytophthora, classified in oomycetes, includes more than 120 species that are mostly recognized worldwide as highly invasive plant pathogens. After 2000, over 50 new species of Phytophthora were identified internationally as plant pathogens occurring in crops and forest trees. In Korea, Phytophthora is also one of the most serious plant pathogens. To date, 22 species (about one-fifth of known species of the genus have been identified and reported as plant pathogens in the country. The likelihood of new exotic Phytophthora species being introduced into Korea continues to increase, thus necessitating intensive plant quarantine inspections. As new potential threats to plant health in Korea, six Phytophthora species, namely, P. alni, P. inundata, P. kernoviae, P. pinifolia, P. quercina, and P. ramorum, are discussed in this review with focus on history, disease, biology, management, and plant quarantine issues.

Antagonistic interactions between an invasive alien and a native coccinellid species may promote coexistence.

Science.gov (United States)

Hentley, William T; Vanbergen, Adam J; Beckerman, Andrew P; Brien, Melanie N; Hails, Rosemary S; Jones, T Hefin; Johnson, Scott N

2016-07-01

Despite the capacity of invasive alien species to alter ecosystems, the mechanisms underlying their impact remain only partly understood. Invasive alien predators, for example, can significantly disrupt recipient communities by consuming prey species or acting as an intraguild predator (IGP). Behavioural interactions are key components of interspecific competition between predators, yet these are often overlooked invasion processes. Here, we show how behavioural, non-lethal IGP interactions might facilitate the establishment success of an invading alien species. We experimentally assessed changes in feeding behaviour (prey preference and consumption rate) of native UK coccinellid species (Adalia bipunctata and Coccinella septempunctata), whose populations are, respectively, declining and stable, when exposed to the invasive intraguild predator, Harmonia axyridis. Using a population dynamics model parameterized with these experimental data, we predicted how intraguild predation, accommodating interspecific behavioural interactions, might impact the abundance of the native and invasive alien species over time. When competing for the same aphid resource, the feeding rate of A. bipunctata significantly increased compared to the feeding in isolation, while the feeding rate of H. axyridis significantly decreased. This suggests that despite significant declines in the UK, A. bipunctata is a superior competitor to the intraguild predator H. axyridis. In contrast, the behaviour of non-declining C. septempunctata was unaltered by the presence of H. axyridis. Our experimental data show the differential behavioural plasticity of competing native and invasive alien predators, but do not explain A. bipunctata declines observed in the UK. Using behavioural plasticity as a parameter in a population dynamic model for A. bipunctata and H. axyridis, coexistence is predicted between the native and invasive alien following an initial period of decline in the native species. We

Floral advertisement scent in a changing plant-pollinators market.

Science.gov (United States)

Filella, Iolanda; Primante, Clara; Llusià, Joan; Martín González, Ana M; Seco, Roger; Farré-Armengol, Gerard; Rodrigo, Anselm; Bosch, Jordi; Peñuelas, Josep

2013-12-05

Plant-pollinator systems may be considered as biological markets in which pollinators choose between different flowers that advertise their nectar/pollen rewards. Although expected to play a major role in structuring plant-pollinator interactions, community-wide patterns of flower scent signals remain largely unexplored. Here we show for the first time that scent advertisement is higher in plant species that bloom early in the flowering period when pollinators are scarce relative to flowers than in species blooming later in the season when there is a surplus of pollinators relative to flowers. We also show that less abundant flowering species that may compete with dominant species for pollinator visitation early in the flowering period emit much higher proportions of the generalist attractant β-ocimene. Overall, we provide a first community-wide description of the key role of seasonal dynamics of plant-specific flower scent emissions, and reveal the coexistence of contrasting plant signaling strategies in a plant-pollinator market.

Seasonal variation in water uptake patterns of three plant species based on stable isotopes in the semi-arid Loess Plateau.

Science.gov (United States)

Wang, Jian; Fu, Bojie; Lu, Nan; Zhang, Li

2017-12-31

Water is a limiting factor and significant driving force for ecosystem processes in arid and semi-arid areas. Knowledge of plant water uptake pattern is indispensable for understanding soil-plant interactions and species coexistence. The 'Grain for Green' project that started in 1999 in the Loess Plateau of China has led to large scale vegetation change. However, little is known about the water uptake patterns of the main plant species that inhabit in this region. In this study, the seasonal variations in water uptake patterns of three representative plant species, Stipa bungeana, Artemisia gmelinii and Vitex negundo, that are widely distributed in the semi-arid area of the Loess Plateau, were identified by using dual stable isotopes of δ 2 H and δ 18 O in plant and soil water coupled with a Bayesian mixing model MixSIAR. The soil water at the 0-120cm depth contributed 79.54±6.05% and 79.94±8.81% of the total water uptake of S. bungeana and A. gmelinii, respectively, in the growing season. The 0-40cm soil contributed the most water in July (74.20±15.20%), and the largest proportion of water (33.10±15.20%) was derived from 120-300cm soils in August for A. gmelinii. However, V. negundo obtained water predominantly from surface soil horizons (0-40cm) and then switched to deep soil layers (120-300cm) as the season progressed. This suggested that V. negundo has a greater degree of ecological plasticity as it could explore water sources from deeper soils as the water stress increased. This capacity can mainly be attributed to its functionally dimorphic root system. V. negundo may have a competitive advantage when encountering short-term drought. The ecological plasticity of plant water use needs to be considered in plant species selection and ecological management and restoration of the arid and semi-arid ecosystems in the Loess Plateau. Copyright © 2017 Elsevier B.V. All rights reserved.

Opposing effects of floral visitors and soil conditions on the determinants of competitive outcomes maintain species diversity in heterogeneous landscapes.

Science.gov (United States)

Lanuza, Jose B; Bartomeus, Ignasi; Godoy, Oscar

2018-06-01

Theory argues that both soil conditions and aboveground trophic interactions have equivalent potential to limit or promote plant diversity. However, it remains unexplored how they jointly modify the niche differences stabilising species coexistence and the average fitness differences driving competitive dominance. We conducted a field study in Mediterranean annual grasslands to parameterise population models of six competing plant species. Spatially explicit floral visitor assemblages and soil salinity variation were characterised for each species. Both floral visitors and soil salinity modified species population dynamics via direct changes in seed production and indirect changes in competitive responses. Although the magnitude and sign of these changes were species-specific, floral visitors promoted coexistence at neighbourhood scales, while soil salinity did so over larger scales by changing the superior competitors' identity. Our results show how below and aboveground interactions maintain diversity in heterogeneous landscapes through their opposing effects on the determinants of competitive outcomes. © 2018 John Wiley & Sons Ltd/CNRS.

Taxonomic perspective of plant species yielding vegetable oils used ...

African Journals Online (AJOL)

A search conducted to determine the plants yielding vegetable oils resulted in 78 plant species with potential use in cosmetics and skin care products. The taxonomic position of these plant species is described with a description of vegetable oils from these plants and their use in cosmetic and skin care products.

Plant Size as Determinant of Species Richness of Herbivores, Natural Enemies and Pollinators across 21 Brassicaceae Species.

Directory of Open Access Journals (Sweden)

Hella Schlinkert

Full Text Available Large plants are often more conspicuous and more attractive for associated animals than small plants, e.g. due to their wider range of resources. Therefore, plant size can positively affect species richness of associated animals, as shown for single groups of herbivores, but studies usually consider intraspecific size differences of plants in unstandardised environments. As comprehensive tests of interspecific plant size differences under standardised conditions are missing so far, we investigated effects of plant size on species richness of all associated arthropods using a common garden experiment with 21 Brassicaceae species covering a broad interspecific plant size gradient from 10 to 130 cm height. We recorded plant associated ecto- and endophagous herbivores, their natural enemies and pollinators on and in each aboveground plant organ, i.e. flowers, fruits, leaves and stems. Plant size (measured as height from the ground, the number of different plant organ entities and their biomass were assessed. Increasing plant size led to increased species richness of associated herbivores, natural enemies and pollinating insects. This pattern was found for ectophagous and endophagous herbivores, their natural enemies, as well as for herbivores associated with leaves and fruits and their natural enemies, independently of the additional positive effects of resource availability (i.e. organ biomass or number of entities and, regarding natural enemies, herbivore species richness. We found a lower R2 for pollinators compared to herbivores and natural enemies, probably caused by the high importance of flower characteristics for pollinator species richness besides plant size. Overall, the increase in plant height from 10 to 130 cm led to a 2.7-fold increase in predicted total arthropod species richness. In conclusion, plant size is a comprehensive driver of species richness of the plant associated arthropods, including pollinators, herbivores and their

Burrow characteristics of the co-existing sibling species Mus booduga and Mus terricolor and the genetic basis of adaptation to hypoxic/hypercapnic stress

Directory of Open Access Journals (Sweden)

Narayan Gopeshwar

2009-04-01

Full Text Available Abstract Background The co-existing, sibling species Mus booduga and Mus terricolor show a difference in site-preference for burrows. The former build them in flat portion of the fields while the latter make burrows in earthen mounds raised for holding water in cultivated fields. In northern India which experiences great variation in climatic condition between summer and winter, M. booduga burrows have an average depth of 41 cm, as against 30 cm in southern India with less climatic fluctuation. M. terricolor burrows are about 20 cm deep everywhere. The three chromosomal species M. terricolor I, II and III have identical burrows, including location of the nest which is situated at the highest position. In contrast, in M. booduga burrows, the nest is at the lowest position. Results The nest chamber of M. booduga is located at greater depth than the nest chamber of M. terricolor. Also, in the burrows of M. booduga the exchange of air takes place only from one side (top surface in contrast to the burrows of M. terricolor where air exchange is through three sides. Hence, M. booduga lives in relatively more hypoxic and hypercapnic conditions than M. terricolor. We observed the fixation of alternative alleles in M. booduga and M. terricolor at Superoxide dismutase-1 (Sod-1, Transferrin (Trf and Hemoglobin beta chain (Hbb loci. All the three are directly or indirectly dependent on oxygen concentration for function. In addition to these, there are differences in burrow patterns and site-preference for burrows suggesting difference in probable adaptive strategy in these co-existing sibling species. Conclusion The burrow structure and depth of nest of the chromosomal species M. terricolor I, II and III are same everywhere probably due to the recency of their evolutionary divergence. Moreover, there is lack of competition for the well-adapted 'microhabitats' since they are non-overlapping in distribution. However, the co-existing sibling species M. booduga

Performance of dryland and wetland plant species on extensive green roofs.

Science.gov (United States)

MacIvor, J Scott; Ranalli, Melissa A; Lundholm, Jeremy T

2011-04-01

Green roofs are constructed ecosystems where plants perform valuable services, ameliorating the urban environment through roof temperature reductions and stormwater interception. Plant species differ in functional characteristics that alter ecosystem properties. Plant performance research on extensive green roofs has so far indicated that species adapted to dry conditions perform optimally. However, in moist, humid climates, species typical of wetter soils might have advantages over dryland species. In this study, survival, growth and the performance of thermal and stormwater capture functions of three pairs of dryland and wetland plant species were quantified using an extensive modular green roof system. Seedlings of all six species were germinated in a greenhouse and planted into green roof modules with 6 cm of growing medium. There were 34 treatments consisting of each species in monoculture and all combinations of wet- and dryland species in a randomized block design. Performance measures were survival, vegetation cover and roof surface temperature recorded for each module over two growing seasons, water loss (an estimate of evapotranspiration) in 2007, and albedo and water capture in 2008. Over two seasons, dryland plants performed better than wetland plants, and increasing the number of dryland species in mixtures tended to improve functioning, although there was no clear effect of species or habitat group diversity. All species had survival rates >75 % after the first winter; however, dryland species had much greater cover, an important indicator of green roof performance. Sibbaldiopsis tridentata was the top performing species in monoculture, and was included in the best treatments. Although dryland species outperformed wetland species, planting extensive green roofs with both groups decreased performance only slightly, while increasing diversity and possibly habitat value. This study provides further evidence that plant composition and diversity can

Herbivory and dominance shifts among exotic and congeneric native plant species during plant community establishment

DEFF Research Database (Denmark)

Engelkes, Tim; Meisner, Annelein; Morriën, Elly

2016-01-01

in a riparian ecosystem during early establishment of invaded communities. We planted ten plant communities each consisting of three individuals of each of six exotic plant species as well as six phylogenetically related natives. Exotic plant species were selected based on a rapid recent increase in regional...... abundance, the presence of a congeneric native species, and their co-occurrence in the riparian ecosystem. All plant communities were covered by tents with insect mesh. Five tents were open on the leeward side to allow herbivory. The other five tents were completely closed in order to exclude insects...... and vertebrates. Herbivory reduced aboveground biomass by half and influenced which of the plant species dominated the establishing communities. Exposure to herbivory did not reduce the total biomass of natives more than that of exotics, so aboveground herbivory did not selectively enhance exotics during...

Distribution and content of ellagitannins in Finnish plant species.

Science.gov (United States)

Moilanen, Johanna; Koskinen, Piia; Salminen, Juha-Pekka

2015-08-01

The results of a screening study, in which a total of 82 Finnish plant species were studied for their ellagitannin composition and content, are presented. The total ellagitannin content was determined by HPLC-DAD, the detected ellagitannins were further characterized by HPLC-ESI-QTOF-MS and divided into four structurally different sub-groups. Thirty plant species were found to contain ellagitannins and the ellagitannin content in the crude extracts varied from few mgg(-1) to over a hundred mgg(-1). Plant families that were rich in ellagitannins (>90mgg(-1) of the crude extract) were Onagraceae, Lyhtraceae, Geraniaceae, Elaeagnaceae, Fagaceae and some species from Rosaceae. Plant species that contained moderate amounts of ellagitannins (31-89mgg(-1) of the crude extract) were representatives of the family Rosaceae. Plant species that contained low amounts of ellagitannins (1-30mgg(-1) of the crude extract) were representatives of the families Betulaceae and Myricaceae. The specific ellagitannin composition of the species allowed their chemotaxonomic classification and the comparison between the older Cronquist's classification and the nowadays preferred Angiosperm Phylogeny Group classification. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thermal Hyperspectral Remote Sensing for Plant Species and Stress Detection

Science.gov (United States)

Schlerf, M.; Rock, G.; Ullah, S.; Gerhards, M.; Udelhoven, T.; Skidmore, A. K.

2014-12-01

Thermal infrared (TIR) spectroscopy offers a novel opportunity for measuring emissivity spectra of natural surfaces. Emissivity spectra are not directly measured, they first have to be retrieved from the raw measurements. Once retrieved, the spectra can be used, for example, to discriminate plant species or to detect plant stress. Knowledge of plant species distribution is essential for the sustainable management of ecosystems. Remote sensing of plant species has so far mostly been limited to data in the visible and near-infrared where, however, different species often reveal similar reflectance curves. Da Luz and Crowley showed in a recent paper that in the TIR plants indeed have distinct spectral features. Also with a certain species, subtle changes of emissivity in certain wavebands may occur, when biochemical compounds change due to osmotic adjustment induced by water stress. Here we show, that i) emissive imaging spectroscopy allows for reliable and accurate retrieval of plant emissivity spectra, ii) emissivity spectra are well suited to discriminate plant species, iii) a reduction in stomatal conductance (caused by stress) changes the thermal infrared signal. For 13 plant species in the laboratory and for 8 plant species in a field setup emissivity spectra were retrieved. A comparison shows, that for most species the shapes of the emissivity curves agree quite well, but that clear offsets between the two types of spectra exist. Discrimination analysis revealed that based on the lab spectra, 13 species could be distinguished with an average overall classification accuracy of 92% using the 6 best spectral bands. For the field spectra (8 species), a similar high OAA of 89% was achieved. Species discrimination is likely to be possible due to variations in the composition of the superficial epidermal layer of plant leaves and in internal chemical concentrations producing unique emissivity features. However, to date, which spectral feature is responsible for which

Effect of co-existing plant specie on soil microbial activity under heavy metal stress

International Nuclear Information System (INIS)

Nwuche, C. O.; Ugoji, E. O.

2010-01-01

The influence of plant primary compounds on the activity of soil microbial communities under heavy metal stress was studied in a pot-culture field experiment conducted in a green house. Amaranthus spinosus was cultivated in an agricultural soil previously amended in the laboratory with solutions of different trace elements in two separate treatment modes: singly and in combination. Culture-independent metabolism based indices such as the rate of carbon and nitrogen mineralization, microbial biomass carbon and soil basal respiration were monitored fortnightly over a period of six weeks. Result shows that plant detritus have significant modifying effect on soil microbe-metal interactions. Data on microbial and biochemical processes in the respective mesocosms did not vary from control; not even in mesocosms containing very high concentrations of copper, zinc and nickel. The soil microbial biomass carbon and the rate of carbon and nitrogen cycling were not impeded by the respective metal treatment while the respiration responses increased as a result of increase in metabolic activity of the soil microbes. The plant based substrates enabled the soil microflora to resist high metal contamination because of its tendency to absorb large amounts of inorganic cations.

Individual species affect plant traits structure in their surroundings: evidence of functional mechanisms of assembly.

Science.gov (United States)

Chacón-Labella, Julia; de la Cruz, Marcelino; Pescador, David S; Escudero, Adrián

2016-04-01

Evaluating community assembly through the use of functional traits is a promising tool for testing predictions arising from Niche and Coexistence theories. Although interactions among neighboring species and their inter-specific differences are known drivers of coexistence with a strong spatial signal, assessing the role of individual species on the functional structure of the community at different spatial scales remains a challenge. Here, we ask whether individual species exert a measurable effect on the spatial organization of different functional traits in local assemblages. We first propose and compute two functions that describe different aspects of functional trait organization around individual species at multiple scales: individual weighted mean area relationship and individual functional diversity area relationship. Secondly, we develop a conceptual model on the relationship and simultaneous variation of these two metrics, providing five alternative scenarios in response to the ability of some target species to modify its neighbor environment and the possible assembly mechanisms involved. Our results show that some species influence the spatial structure of specific functional traits, but their effects were always restricted to the finest spatial scales. In the basis of our conceptual model, the observed patterns point to two main mechanisms driving the functional structure of the community at the fine scale, "biotic" filtering meditated by individual species and resource partitioning driven by indirect facilitation rather than by competitive mechanisms.

Connecting infrared spectra with plant traits to identify species

Science.gov (United States)

Buitrago, Maria F.; Skidmore, Andrew K.; Groen, Thomas A.; Hecker, Christoph A.

2018-05-01

Plant traits are used to define species, but also to evaluate the health status of forests, plantations and crops. Conventional methods of measuring plant traits (e.g. wet chemistry), although accurate, are inefficient and costly when applied over large areas or with intensive sampling. Spectroscopic methods, as used in the food industry and mineralogy, are nowadays applied to identify plant traits, however, most studies analysed visible to near infrared, while infrared spectra of longer wavelengths have been little used for identifying the spectral differences between plant species. This study measured the infrared spectra (1.4-16.0 μm) on individual, fresh leaves of 19 species (from herbaceous to woody species), as well as 14 leaf traits for each leaf. The results describe at which wavelengths in the infrared the leaves' spectra can differentiate most effectively between these plant species. A Quadratic Discrimination Analysis (QDA) shows that using five bands in the SWIR or the LWIR is enough to accurately differentiate these species (Kappa: 0.93, 0.94 respectively), while the MWIR has a lower classification accuracy (Kappa: 0.84). This study also shows that in the infrared spectra of fresh leaves, the identified species-specific features are correlated with leaf traits as well as changes in their values. Spectral features in the SWIR (1.66, 1.89 and 2.00 μm) are common to all species and match the main features of pure cellulose and lignin spectra. The depth of these features varies with changes of cellulose and leaf water content and can be used to differentiate species in this region. In the MWIR and LWIR, the absorption spectra of leaves are formed by key species-specific traits including lignin, cellulose, water, nitrogen and leaf thickness. The connection found in this study between leaf traits, features and spectral signatures are novel tools to assist when identifying plant species by spectroscopy and remote sensing.

The threshold of coexistence and critical behaviour of a predator-prey cellular automaton

International Nuclear Information System (INIS)

Arashiro, Everaldo; Tome, Tania

2007-01-01

We study a probabilistic cellular automaton to describe two population biology problems: the threshold of species coexistence in a predator-prey system and the spreading of an epidemic in a population. By carrying out mean-field approximations and numerical simulations we obtain the phase boundaries (thresholds) related to the transition between an active state, where prey and predators present a stable coexistence, and a prey absorbing state. The numerical estimates for the critical exponents show that the transition belongs to the directed percolation universality class. In the limit where the cellular automaton maps into a model for the spreading of an epidemic with immunization we observe a crossover from directed percolation class to the dynamic percolation class. Patterns of growing clusters related to species coexistence and spreading of epidemic are shown and discussed

Biodiversity hotspots house most undiscovered plant species.

Science.gov (United States)

Joppa, Lucas N; Roberts, David L; Myers, Norman; Pimm, Stuart L

2011-08-09

For most organisms, the number of described species considerably underestimates how many exist. This is itself a problem and causes secondary complications given present high rates of species extinction. Known numbers of flowering plants form the basis of biodiversity "hotspots"--places where high levels of endemism and habitat loss coincide to produce high extinction rates. How different would conservation priorities be if the catalog were complete? Approximately 15% more species of flowering plant are likely still undiscovered. They are almost certainly rare, and depending on where they live, suffer high risks of extinction from habitat loss and global climate disruption. By using a model that incorporates taxonomic effort over time, regions predicted to contain large numbers of undiscovered species are already conservation priorities. Our results leave global conservation priorities more or less intact, but suggest considerably higher levels of species imperilment than previously acknowledged.

Site and plant species are important determinants of the Methylobacterium community composition in the plant phyllosphere.

Science.gov (United States)

Knief, Claudia; Ramette, Alban; Frances, Lisa; Alonso-Blanco, Carlos; Vorholt, Julia A

2010-06-01

The plant phyllosphere constitutes a habitat for numerous microorganisms; among them are members of the genus Methylobacterium. Owing to the ubiquitous occurrence of methylobacteria on plant leaves, they represent a suitable target for studying plant colonization patterns. The influence of the factor site, host plant species, time and the presence of other phyllosphere bacteria on Methylobacterium community composition and population size were evaluated in this study. Leaf samples were collected from Arabidopsis thaliana or Medicago truncatula plants and from the surrounding plant species at several sites. The abundance of cultivable Methylobacterium clearly correlated with the abundance of other phyllosphere bacteria, suggesting that methylobacteria constitute a considerable and rather stable fraction of the phyllosphere microbiota under varying environmental conditions. Automated ribosomal intergenic spacer analysis (ARISA) was applied to characterize the Methylobacterium community composition and showed the presence of similar communities on A. thaliana plants at most sites in 2 consecutive years of sampling. A substantial part of the observed variation in the community composition was explained by site and plant species, especially in the case of the plants collected at the Arabidopsis sites (50%). The dominating ARISA peaks that were detected on A. thaliana plants were found on other plant species grown at the same site, whereas some different peaks were detected on A. thaliana plants from other sites. This indicates that site-specific factors had a stronger impact on the Methylobacterium community composition than did plant-specific factors and that the Methylobacterium-plant association is not highly host plant species specific.

Plant species richness enhances nitrogen retention in green roof plots.

Science.gov (United States)

Johnson, Catherine; Schweinhart, Shelbye; Buffam, Ishi

2016-10-01

Vegetated (green) roofs have become common in many cities and are projected to continue to increase in coverage, but little is known about the ecological properties of these engineered ecosystems. In this study, we tested the biodiversity-ecosystem function hypothesis using commercially available green roof trays as replicated plots with varying levels of plant species richness (0, 1, 3, or 6 common green roof species per plot, using plants with different functional characteristics). We estimated accumulated plant biomass near the peak of the first full growing season (July 2013) and measured runoff volume after nearly every rain event from September 2012 to September 2013 (33 events) and runoff fluxes of inorganic nutrients ammonium, nitrate, and phosphate from a subset of 10 events. We found that (1) total plant biomass increased with increasing species richness, (2) green roof plots were effective at reducing storm runoff, with vegetation increasing water retention more than soil-like substrate alone, but there was no significant effect of plant species identity or richness on runoff volume, (3) green roof substrate was a significant source of phosphate, regardless of presence/absence of plants, and (4) dissolved inorganic nitrogen (DIN = nitrate + ammonium) runoff fluxes were different among plant species and decreased significantly with increasing plant species richness. The variation in N retention was positively related to variation in plant biomass. Notably, the increased biomass and N retention with species richness in this engineered ecosystem are similar to patterns observed in published studies from grasslands and other well-studied ecosystems. We suggest that more diverse plantings on vegetated roofs may enhance the retention capacity for reactive nitrogen. This is of importance for the sustained health of vegetated roof ecosystems, which over time often experience nitrogen limitation, and is also relevant for water quality in receiving waters

Invasive Plant Species in the National Parks of Vietnam

OpenAIRE

Bernard Dell; Pham Quang Thu; Dang Thanh Tan

2012-01-01

The impact of invasive plant species in national parks and forests in Vietnam is undocumented and management plans have yet to be developed. Ten national parks, ranging from uncut to degraded forests located throughout Vietnam, were surveyed for invasive plant species. Transects were set up along roads, trails where local people access park areas, and also tracks through natural forest. Of 134 exotic weeds, 25 were classified as invasive species and the number of invasive species ranged from ...

Generalist Bee Species on Brazilian Bee-Plant Interaction Networks

Directory of Open Access Journals (Sweden)

Astrid de Matos Peixoto Kleinert

2012-01-01

Full Text Available Determining bee and plant interactions has an important role on understanding general biology of bee species as well as the potential pollinating relationship between them. Bee surveys have been conducted in Brazil since the end of the 1960s. Most of them applied standardized methods and had identified the plant species where the bees were collected. To analyze the most generalist bees on Brazilian surveys, we built a matrix of bee-plant interactions. We estimated the most generalist bees determining the three bee species of each surveyed locality that presented the highest number of interactions. We found 47 localities and 39 species of bees. Most of them belong to Apidae (31 species and Halictidae (6 families and to Meliponini (14 and Xylocopini (6 tribes. However, most of the surveys presented Apis mellifera and/or Trigona spinipes as the most generalist species. Apis mellifera is an exotic bee species and Trigona spinipes, a native species, is also widespread and presents broad diet breath and high number of individuals per colony.

Differential responses of soil bacteria, fungi, archaea and protists to plant species richness and plant functional group identity.

Science.gov (United States)

Dassen, Sigrid; Cortois, Roeland; Martens, Henk; de Hollander, Mattias; Kowalchuk, George A; van der Putten, Wim H; De Deyn, Gerlinde B

2017-08-01

Plants are known to influence belowground microbial community structure along their roots, but the impacts of plant species richness and plant functional group (FG) identity on microbial communities in the bulk soil are still not well understood. Here, we used 454-pyrosequencing to analyse the soil microbial community composition in a long-term biodiversity experiment at Jena, Germany. We examined responses of bacteria, fungi, archaea, and protists to plant species richness (communities varying from 1 to 60 sown species) and plant FG identity (grasses, legumes, small herbs, tall herbs) in bulk soil. We hypothesized that plant species richness and FG identity would alter microbial community composition and have a positive impact on microbial species richness. Plant species richness had a marginal positive effect on the richness of fungi, but we observed no such effect on bacteria, archaea and protists. Plant species richness also did not have a large impact on microbial community composition. Rather, abiotic soil properties partially explained the community composition of bacteria, fungi, arbuscular mycorrhizal fungi (AMF), archaea and protists. Plant FG richness did not impact microbial community composition; however, plant FG identity was more effective. Bacterial richness was highest in legume plots and lowest in small herb plots, and AMF and archaeal community composition in legume plant communities was distinct from that in communities composed of other plant FGs. We conclude that soil microbial community composition in bulk soil is influenced more by changes in plant FG composition and abiotic soil properties, than by changes in plant species richness per se. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Changes in semi-arid plant species associations along a livestock grazing gradient.

Directory of Open Access Journals (Sweden)

Hugo Saiz

Full Text Available In semi-arid ecosystems, vegetation is heterogeneously distributed, with plant species often associating in patches. These associations between species are not constant, but depend on the particular response of each species to environmental factors. Here, we investigated how plant species associations change in response to livestock grazing in a semi-arid ecosystem, Cabo de Gata-Níjar Natural Park in South East Spain. We established linear point-intercept transects at four sites with different grazing intensity, and recorded all species at each point. We investigated plant associations by comparing the number of times that each pair of species occurred at the same spatial point (co-occurrences, with the expected number of times based on species abundances. We also assessed associations for each shrub and grass species by considering all their pairs of associations and for the whole plant community by considering all pairs of associations on each site. At all sites, the plant community had a negative pattern of association, with fewer co-occurrences than expected. Negative association in the plant community increased at maximum grazing intensity. Most species associated as expected, particularly grass species, and positive associations were most important at intermediate grazing intensities. No species changed its type of association along the grazing gradient. We conclude that in the present plant community, grazing-resistant species compete among themselves and segregate in space. Some shrub species act as refuges for grazing-sensitive species that benefit from being spatially associated with shrub species, particularly at intermediate grazing intensities where positive associations were highest. At high grazing intensity, these shrubs can no longer persist and positive associations decrease due to the disappearance of refuges. Spatial associations between plant species and their response to grazing help identify the factors that organize

Ozone injury to some Japanese woody plant species in summer

Energy Technology Data Exchange (ETDEWEB)

Kadota, M; Ohta, K

1972-01-01

Ozone is an important constituent of photochemical oxidant smog. This paper reveals the semiquantitative responses of various Japanese woody plant species to ozone (0.25 ppm). Plant species examined in this investigation include four coniferous trees, eleven evergreen broad-leaf trees, and twenty-one deciduous broad-leaf trees or shrubs. Generally, plants having thin leaves were susceptible. The plant species with higher activity of photosynthesis appeared to be more susceptible. As a whole, evergreen broad-leaf trees could be said to be more resistant to ozone than deciduous broad-leaf trees.

Host plant use among closely related Anaea butterfly species (Lepidoptera, Nymphalidae, Charaxinae

Directory of Open Access Journals (Sweden)

QUEIROZ J. M.

2002-01-01

Full Text Available There is a great number of Charaxinae (Lepidoptera: Nymphalidae species in the tropics whose larvae feed on several plant families. However the genus Anaea is almost always associated with Croton species (Euphorbiaceae. This work describes patterns of host plant use by immature and adult abundance on different vertical strata of sympatric Anaea species in a forest of Southeastern Brazil. Quantitative samples of leaves were taken in April/1999 and May/2000 to collect eggs and larvae of four Anaea species on C.alchorneicarpus, C. floribundus and C. salutaris in a semideciduous forest. Sampled leaves were divided into three classes of plant phenological stage: saplings, shrubs and trees. The results showed that the butterfly species are segregating in host plant use on two scales: host plant species and plant phenological stages. C. alchorneicarpus was used by only one Anaea species, whereas C. floribundus was used by three species and C. salutaris by four Anaea species. There was one Anaea species concentrated on sapling, another on sapling/shrub and two others on shrub/tree leaves. Adults of Anaea were more frequent at canopy traps but there were no differences among species caught in traps at different vertical positions. This work supplements early studies on host plant use among Charaxinae species and it describes how a guild of closely related butterfly species may be organized in a complex tropical habitat.

Invasive exotic plant species in Sierra Nevada ecosystems

Science.gov (United States)

Carla M. D' Antonio; Eric L. Berlow; Karen L. Haubensak

2004-01-01

The Sierra Nevada is a topographically and floristically diverse region of the western United States. While it comprises only a fifth of the total land area of California, half of the native plant species in the state occur within the range. In addition, more than 400 plant species are endemic to the Sierra Nevada and many of these are listed as threatened or have...

On the reasons that natural regeneration is important for species coexistence in tropical forests

Directory of Open Access Journals (Sweden)

Natalia Norden

2014-12-01

Full Text Available Plant regeneration plays a critical role in the maintenance of species diversity in tropical rainforests. This is a multistage process, including seed production, dispersal, germination and subsequent seedling establishment. All these stages represent major bottlenecks in plant demography, as early stages in the plant cycle (seeds and seedlings are the most vulnerable to environmental hazards, and are therefore subject to high mortality risks. The outcome of these ecological filters will determine not only seedling spatial distribution, but also the potential area of tree distribution. Seed dispersal and subsequent seedling establishment therefore play a critical role in the structuring of tree communities. Here, I review the main four ecological processes driving seedling recruitment in tropical forests. First, dispersal limitation is the failure of seeds to reach suitable microsites for seedling establishment. Once this filter is overcome, environmental factors can considerably affect seedling spatial distribution. Temporal fluctuations in these processes result in an important variation in recruitment success over time, and add a stochastic component to seedling regeneration. Finally, negative-density dependence regulates species relative abundance in the seedling layer by limiting conspecific recruitment through the attack of pathogen, fungi and herbivores.

Interspecific competition of early successional plant species in ex-arable fields as influenced by plant-soil feedback

OpenAIRE

Jing, Jingying; Bezemer, T. Martijn; Van der Putten, Wim H.

2015-01-01

Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from early-stage ex-arable fields to examine how intra- and interspecific plant–soil feedbacks affect the performance of 10 conditioning species and the focal species, Jacobaea vulgaris. Plants were grown alon...

Phylogenetically poor plant communities receive more alien species, which more easily coexist with natives

Czech Academy of Sciences Publication Activity Database

Gerhold, P.; Pärtel, M.; Tackenberg, O.; Hennekens, S.M.; Bartish, Igor; Schaminée, J.H.J.; Fergus, A. J. F.; Ozinga, W.A.; Prinzing, A.

2011-01-01

Roč. 177, č. 5 (2011), s. 68-680 ISSN 0003-0147 Institutional research plan: CEZ:AV0Z60050516 Keywords : species richness * phylogenetic diversity * invasions Subject RIV: EF - Botanics Impact factor: 4.725, year: 2011

Growth and stable isotope signals associated with drought-related mortality in saplings of two coexisting pine species.

Science.gov (United States)

Herrero, Asier; Castro, Jorge; Zamora, Regino; Delgado-Huertas, Antonio; Querejeta, José I

2013-12-01

Drought-induced events of massive tree mortality appear to be increasing worldwide. Species-specific vulnerability to drought mortality may alter patterns of species diversity and affect future forest composition. We have explored the consequences of the extreme drought of 2005, which caused high sapling mortality (approx. 50 %) among 10-year-old saplings of two coexisting pine species in the Mediterranean mountains of Sierra Nevada (Spain): boreo-alpine Pinus sylvestris and Mediterranean P. nigra. Sapling height growth, leaf δ(13)C and δ(18)O, and foliar nitrogen concentration in the four most recent leaf cohorts were measured in dead and surviving saplings. The foliar isotopic composition of dead saplings (which reflects time-integrated leaf gas-exchange until mortality) displayed sharp increases in both δ(13)C and δ(18)O during the extreme drought of 2005, suggesting an important role of stomatal conductance (g(s)) reduction and diffusional limitations to photosynthesis in mortality. While P. nigra showed decreased growth in 2005 compared to the previous wetter year, P. sylvestris maintained similar growth levels in both years. Decreased growth, coupled with a sharper increase in foliar δ(18)O during extreme drought in dead saplings, indicate a more conservative water use strategy for P. nigra. The different physiological behavior of the two pine species in response to drought (further supported by data from surviving saplings) may have influenced 2005 mortality rates, which contributed to 2.4-fold greater survival for P. nigra over the lifespan of the saplings. This species-specific vulnerability to extreme drought could lead to changes in dominance and distribution of pine species in Mediterranean mountain forests.

Widespread plant species: natives vs. aliens in our changing world

Science.gov (United States)

Stohlgren, Thomas J.; Pyšek, Petr; Kartesz, John; Nishino, Misako; Pauchard, Aníbal; Winter, Marten; Pino, Joan; Richardson, David M.; Wilson, John R.U.; Murray, Brad R.; Phillips, Megan L.; Ming-yang, Li; Celesti-Grapow, Laura; Font, Xavier

2011-01-01

Estimates of the level of invasion for a region are traditionally based on relative numbers of native and alien species. However, alien species differ dramatically in the size of their invasive ranges. Here we present the first study to quantify the level of invasion for several regions of the world in terms of the most widely distributed plant species (natives vs. aliens). Aliens accounted for 51.3% of the 120 most widely distributed plant species in North America, 43.3% in New South Wales (Australia), 34.2% in Chile, 29.7% in Argentina, and 22.5% in the Republic of South Africa. However, Europe had only 1% of alien species among the most widespread species of the flora. Across regions, alien species relative to native species were either as well-distributed (10 comparisons) or more widely distributed (5 comparisons). These striking patterns highlight the profound contribution that widespread invasive alien plants make to floristic dominance patterns across different regions. Many of the most widespread species are alien plants, and, in particular, Europe and Asia appear as major contributors to the homogenization of the floras in the Americas. We recommend that spatial extent of invasion should be explicitly incorporated in assessments of invasibility, globalization, and risk assessments.

Widespread plant species: Natives versus aliens in our changing world

Science.gov (United States)

Stohlgren, T.J.; Pysek, P.; Kartesz, J.; Nishino, M.; Pauchard, A.; Winter, M.; Pino, J.; Richardson, D.M.; Wilson, J.R.U.; Murray, B.R.; Phillips, M.L.; Ming-yang, L.; Celesti-Grapow, L.; Font, X.

2011-01-01

Estimates of the level of invasion for a region are traditionally based on relative numbers of native and alien species. However, alien species differ dramatically in the size of their invasive ranges. Here we present the first study to quantify the level of invasion for several regions of the world in terms of the most widely distributed plant species (natives vs. aliens). Aliens accounted for 51.3% of the 120 most widely distributed plant species in North America, 43.3% in New South Wales (Australia), 34.2% in Chile, 29.7% in Argentina, and 22.5% in the Republic of South Africa. However, Europe had only 1% of alien species among the most widespread species of the flora. Across regions, alien species relative to native species were either as well-distributed (10 comparisons) or more widely distributed (5 comparisons). These striking patterns highlight the profound contribution that widespread invasive alien plants make to floristic dominance patterns across different regions. Many of the most widespread species are alien plants, and, in particular, Europe and Asia appear as major contributors to the homogenization of the floras in the Americas. We recommend that spatial extent of invasion should be explicitly incorporated in assessments of invasibility, globalization, and risk assessments. ?? 2011 Springer Science+Business Media B.V.

Efficient distinction of invasive aquatic plant species from non-invasive related species using DNA barcoding.

Science.gov (United States)

Ghahramanzadeh, R; Esselink, G; Kodde, L P; Duistermaat, H; van Valkenburg, J L C H; Marashi, S H; Smulders, M J M; van de Wiel, C C M

2013-01-01

Biological invasions are regarded as threats to global biodiversity. Among invasive aliens, a number of plant species belonging to the genera Myriophyllum, Ludwigia and Cabomba, and to the Hydrocharitaceae family pose a particular ecological threat to water bodies. Therefore, one would try to prevent them from entering a country. However, many related species are commercially traded, and distinguishing invasive from non-invasive species based on morphology alone is often difficult for plants in a vegetative stage. In this regard, DNA barcoding could become a good alternative. In this study, 242 samples belonging to 26 species from 10 genera of aquatic plants were assessed using the chloroplast loci trnH-psbA, matK and rbcL. Despite testing a large number of primer sets and several PCR protocols, the matK locus could not be amplified or sequenced reliably and therefore was left out of the analysis. Using the other two loci, eight invasive species could be distinguished from their respective related species, a ninth one failed to produce sequences of sufficient quality. Based on the criteria of universal application, high sequence divergence and level of species discrimination, the trnH-psbA noncoding spacer was the best performing barcode in the aquatic plant species studied. Thus, DNA barcoding may be helpful with enforcing a ban on trade of such invasive species, such as is already in place in the Netherlands. This will become even more so once DNA barcoding would be turned into machinery routinely operable by a nonspecialist in botany and molecular genetics. © 2012 Blackwell Publishing Ltd.

Plant Species Identification by Bi-channel Deep Convolutional Networks

Science.gov (United States)

He, Guiqing; Xia, Zhaoqiang; Zhang, Qiqi; Zhang, Haixi; Fan, Jianping

2018-04-01

Plant species identification achieves much attention recently as it has potential application in the environmental protection and human life. Although deep learning techniques can be directly applied for plant species identification, it still needs to be designed for this specific task to obtain the state-of-art performance. In this paper, a bi-channel deep learning framework is developed for identifying plant species. In the framework, two different sub-networks are fine-tuned over their pretrained models respectively. And then a stacking layer is used to fuse the output of two different sub-networks. We construct a plant dataset of Orchidaceae family for algorithm evaluation. Our experimental results have demonstrated that our bi-channel deep network can achieve very competitive performance on accuracy rates compared to the existing deep learning algorithm.

VT Biodiversity Project - Plant and Animal Species Atlas

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) This database contains town-level totals of documented species records for several plant and animal taxa including vascular plants, trees,...

Plant antiherbivore defenses in Fabaceae species of the Chaco.

Science.gov (United States)

Lima, T E; Sartori, A L B; Rodrigues, M L M

2017-01-01

The establishment and maintenance of plant species in the Chaco, one of the widest continuous areas of forests in the South American with sharp climatic variations, are possibly related to biological features favoring plants with particular defenses. This study assesses the physical and chemical defenses mechanisms against herbivores of vegetative and reproductive organs. Its analyses of 12 species of Fabaceae (Leguminosae) collected in remnants of Brazilian Chaco shows that 75% present structural defense characters and 50% have chemical defense - defense proteins in their seeds, like protease inhibitors and lectins. Physical defenses occur mainly on branches (78% of the species), leaves (67%), and reproductive organs (56%). The most common physical characters are trichomes and thorns, whose color represents a cryptic character since it does not contrast with the other plant structures. Defense proteins occur in different concentrations and molecular weight classes in the seeds of most species. Protease inhibitors are reported for the first time in seeds of: Albizia niopoides, Anadenanthera colubrina, Mimosa glutinosa, Prosopis rubriflora, and Poincianella pluviosa. The occurrence of physical and chemical defenses in members of Fabaceae indicate no associations between defense characters in these plant species of the Chaco.

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

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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.

The factors controlling species density in herbaceous plant communities: An assessment

Science.gov (United States)

Grace, J.B.

1999-01-01

This paper evaluates both the ideas and empirical evidence pertaining to the control of species density in herbaceous plant communities. While most theoretical discussions of species density have emphasized the importance of habitat productivity and disturbance regimes, many other factors (e.g. species pools, plant litter accumulation, plant morphology) have been proposed to be important. A review of literature presenting observations on the density of species in small plots (in the vicinity of a few square meters or less), as well as experimental studies, suggests several generalizations: (1) Available data are consistent with an underlying unimodal relationship between species density and total community biomass. While variance in species density is often poorly explained by predictor variables, there is strong evidence that high levels of community biomass are antagonistic to high species density. (2) Community biomass is just one of several factors affecting variations in species density. Multivariate analyses typically explain more than twice as much variance in species density as can be explained by community biomass alone. (3) Disturbance has important and sometimes complex effects on species density. In general, the evidence is consistent with the intermediate disturbance hypothesis but exceptions exist and effects can be complex. (4) Gradients in the species pool can have important influences on patterns of species density. Evidence is mounting that a considerable amount of the observed variability in species density within a landscape or region may result from environmental effects on the species pool. (5) Several additional factors deserve greater consideration, including time lags, species composition, plant morphology, plant density and soil microbial effects. Based on the available evidence, a conceptual model of the primary factors controlling species density is presented here. This model suggests that species density is controlled by the effects of

Functional equivalence, competitive hierarchy and facilitation determine species coexistence in highly invaded grasslands

Czech Academy of Sciences Publication Activity Database

Gross, N.; Liancourt, Pierre; Butters, R.; Ducan, R. P.; Hulme, P. E.

2015-01-01

Roč. 206, č. 1 (2015), s. 175-186 ISSN 0028-646X Institutional support: RVO:67985939 Keywords : biotic interactions * Coexistence * Community assembly Subject RIV: EH - Ecology, Behaviour Impact factor: 7.210, year: 2015

Biogeochemical and Ecomorphological Niche Segregation of Mediterranean Woody Species along a Local Gradient

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Enrique G. de la Riva

2017-07-01

Full Text Available According with niche theory the species are specialized in different ecological niches, being able to coexist as result of a differential use of resources. In this context, the biogeochemical niche hypothesis proposes that species have an optimal elemental composition which results from the link between the chemical and morphological traits for the optimum plant functioning. Thus, and attending to the limiting similarity concept, different elemental composition and plant structure among co-occurring species may reduce competition, promoting different functional niches. Different functional habits associated with leaf life-span or growth forms are associated with different strategies for resource uptake, which could promote niche partitioning. In the present study, based on the biogeochemical niche concept and the use of resources in different proportions, we have focused on leaf traits (morphological and chemical associated with resource uptake, and explored the niche partitioning among functional habits: leaf life-span (deciduous, evergreen, and semideciduous and growth (tree, shrub, and arborescent-shrub. To this end, we have quantified the hypervolume of the leaf functional trait space (both structure and chemical composition in a sample of 45 Mediterranean woody species from Sierra Morena Mountains (Spain growing along a local soil resource gradient. Our results show consistent variation in functional space for woody communities distributed along the environmental gradient. Thus, communities dominated by deciduous trees with faster growth and a predominant acquisitive strategy were characteristic of bottom forests and showed highest leaf biogeochemical space. While semideciduous shrubs and evergreen (arborescent, trees species, characterized by a conservative strategy, dominated ridge forests and showed smaller functional space. In addition, within each topographical zone or environment type, the foliar biogeochemical niche partitioning

Biogeochemical and Ecomorphological Niche Segregation of Mediterranean Woody Species along a Local Gradient.

Science.gov (United States)

de la Riva, Enrique G; Marañón, Teodoro; Violle, Cyrille; Villar, Rafael; Pérez-Ramos, Ignacio M

2017-01-01

According with niche theory the species are specialized in different ecological niches, being able to coexist as result of a differential use of resources. In this context, the biogeochemical niche hypothesis proposes that species have an optimal elemental composition which results from the link between the chemical and morphological traits for the optimum plant functioning. Thus, and attending to the limiting similarity concept, different elemental composition and plant structure among co-occurring species may reduce competition, promoting different functional niches. Different functional habits associated with leaf life-span or growth forms are associated with different strategies for resource uptake, which could promote niche partitioning. In the present study, based on the biogeochemical niche concept and the use of resources in different proportions, we have focused on leaf traits (morphological and chemical) associated with resource uptake, and explored the niche partitioning among functional habits: leaf life-span (deciduous, evergreen, and semideciduous) and growth (tree, shrub, and arborescent-shrub). To this end, we have quantified the hypervolume of the leaf functional trait space (both structure and chemical composition) in a sample of 45 Mediterranean woody species from Sierra Morena Mountains (Spain) growing along a local soil resource gradient. Our results show consistent variation in functional space for woody communities distributed along the environmental gradient. Thus, communities dominated by deciduous trees with faster growth and a predominant acquisitive strategy were characteristic of bottom forests and showed highest leaf biogeochemical space. While semideciduous shrubs and evergreen (arborescent, trees) species, characterized by a conservative strategy, dominated ridge forests and showed smaller functional space. In addition, within each topographical zone or environment type, the foliar biogeochemical niche partitioning would underlie the

A Necessary Condition for Coexistence of Autocatalytic Replicators in a Prebiotic Environment

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Hernandez, Andres F.; Grover, Martha A.

2013-01-01

A necessary, but not sufficient, mathematical condition for the coexistence of short replicating species is presented here. The mathematical condition is obtained for a prebiotic environment, simulated as a fed-batch reactor, which combines monomer recycling, variable reaction order and a fixed monomer inlet flow with two replicator types and two monomer types. An extensive exploration of the parameter space in the model validates the robustness and efficiency of the mathematical condition, with nearly 1.7% of parameter sets meeting the condition and half of those exhibiting sustained coexistence. The results show that it is possible to generate a condition of coexistence, where two replicators sustain a linear growth simultaneously for a wide variety of chemistries, under an appropriate environment. The presence of multiple monomer types is critical to sustaining the coexistence of multiple replicator types. PMID:25369813

Evidence from Individual Inference for High-Dimensional Coexistence: Long-Term Experiments on Recruitment Response

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Clark, James S.; Soltoff, Benjamin D.; Powell, Amanda S.; Read, Quentin D.

2012-01-01

Background For competing species to coexist, individuals must compete more with others of the same species than with those of other species. Ecologists search for tradeoffs in how species might partition the environment. The negative correlations among competing species that would be indicative of tradeoffs are rarely observed. A recent analysis showed that evidence for partitioning the environment is available when responses are disaggregated to the individual scale, in terms of the covariance structure of responses to environmental variation. That study did not relate that variation to the variables to which individuals were responding. To understand how this pattern of variation is related to niche variables, we analyzed responses to canopy gaps, long viewed as a key variable responsible for species coexistence. Methodology/Principal Findings A longitudinal intervention analysis of individual responses to experimental canopy gaps with 12 yr of pre-treatment and 8 yr post-treatment responses showed that species-level responses are positively correlated – species that grow fast on average in the understory also grow fast on average in response to gap formation. In other words, there is no tradeoff. However, the joint distribution of individual responses to understory and gap showed a negative correlation – species having individuals that respond most to gaps when previously growing slowly also have individuals that respond least to gaps when previously growing rapidly (e.g., Morus rubra), and vice versa (e.g., Quercus prinus). Conclusions/Significance Because competition occurs at the individual scale, not the species scale, aggregated species-level parameters and correlations hide the species-level differences needed for coexistence. By disaggregating models to the scale at which the interaction occurs we show that individual variation provides insight for species differences. PMID:22393349

Evidence from individual inference for high-dimensional coexistence: long-term experiments on recruitment response.

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James S Clark

Full Text Available BACKGROUND: For competing species to coexist, individuals must compete more with others of the same species than with those of other species. Ecologists search for tradeoffs in how species might partition the environment. The negative correlations among competing species that would be indicative of tradeoffs are rarely observed. A recent analysis showed that evidence for partitioning the environment is available when responses are disaggregated to the individual scale, in terms of the covariance structure of responses to environmental variation. That study did not relate that variation to the variables to which individuals were responding. To understand how this pattern of variation is related to niche variables, we analyzed responses to canopy gaps, long viewed as a key variable responsible for species coexistence. METHODOLOGY/PRINCIPAL FINDINGS: A longitudinal intervention analysis of individual responses to experimental canopy gaps with 12 yr of pre-treatment and 8 yr post-treatment responses showed that species-level responses are positively correlated--species that grow fast on average in the understory also grow fast on average in response to gap formation. In other words, there is no tradeoff. However, the joint distribution of individual responses to understory and gap showed a negative correlation--species having individuals that respond most to gaps when previously growing slowly also have individuals that respond least to gaps when previously growing rapidly (e.g., Morus rubra, and vice versa (e.g., Quercus prinus. CONCLUSIONS/SIGNIFICANCE: Because competition occurs at the individual scale, not the species scale, aggregated species-level parameters and correlations hide the species-level differences needed for coexistence. By disaggregating models to the scale at which the interaction occurs we show that individual variation provides insight for species differences.

Human population, grasshopper and plant species richness in European countries

Science.gov (United States)

Steck, Claude E.; Pautasso, Marco

2008-11-01

Surprisingly, several studies over large scales have reported a positive spatial correlation of people and biodiversity. This pattern has important implications for conservation and has been documented for well studied taxa such as plants, amphibians, reptiles, birds and mammals. However, it is unknown whether the pattern applies also to invertebrates other than butterflies and more work is needed to establish whether the species-people relationship is explained by both variables correlating with other environmental factors. We studied whether grasshopper species richness (Orthoptera, suborder Caelifera) is related to human population size in European countries. As expected, the number of Caelifera species increases significantly with increasing human population size. But this is not the case when controlling for country area, latitude and number of plant species. Variations in Caelifera species richness are primarily associated with variations in plant species richness. Caelifera species richness also increases with decreasing mean annual precipitation, Gross Domestic Product per capita (used as an indicator for economic development) and net fertility rate of the human population. Our analysis confirms the hypothesis that the broad-scale human population-biodiversity correlations can be explained by concurrent variations in factors other than human population size such as plant species richness, environmental productivity, or habitat heterogeneity. Nonetheless, more populated countries in Europe still have more Caelifera species than less populated countries and this poses a particular challenge for conservation.

Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

Science.gov (United States)

Ding, Tao; Melcher, Ulrich

2016-01-01

Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

Directory of Open Access Journals (Sweden)

Tao Ding

Full Text Available Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

Response of plant species to coal-mine soil materials

Energy Technology Data Exchange (ETDEWEB)

Day, A.D.; Tucker, T.C.; Thames, J.L.

1983-03-01

The two-year Black Mesa Coal Mine Research Study on the area near Kayenta, Arizona investigating the growth and establishment of seven plant species in unmined soil and coal-mined soils found that plant species grew better in unmined soil and that irrigation is essential during seedling establishment for the effective stabilization of coal-mined soils in a semi-arid environment. Differences among the species included variations in germination, response to irrigation, seedling establishment, and stem growth. 12 references, 2 figures, 2 tables.

Effects of plant density and proportion on the interaction between wheat with alexandergrass plants

Directory of Open Access Journals (Sweden)

Leonardo Bianco de Carvalho

2011-01-01

Full Text Available Determination of competitive relationships among plant species requires appropriate experimental designs and method of analysis. The hypothesis of this research was that two species growing in coexistence show different growth and development due to their relative competitiveness. This research aims to measure the relative competitiveness of wheat crop compared to Alexandergrass by the interpretation of plant density and proportional effects using replacement series experiments. Monocultures were cultivated in densities of 1, 3, 5, 10 and 15 plants per pot and analyzed by regression of dry mass data. Mixture experiment was cultivated in wheat:Alexandergrass proportions of 0:6, 1:5, 2:4, 3:3, 4:2, 5:1 and 6:0 plants per pot and analyzed by graphical interpretation of growth and production characteristics. Both experiments were carried out in randomized complete block design with four replicates. Alexandergrass was more sensitive to intraspecific competition than wheat. Alexandergrass was lightly more competitive than wheat. Number and weight of spikes and number of tillers were the wheat characteristics more affected by Alexandergrass interference.

A phase-transition induced by the struggle for life in a competitive coexistence model in ecology

International Nuclear Information System (INIS)

Wio, H.S.; Kuperman, M.N.

1994-07-01

We have studied a spatially homogeneous model of an ecological system consisting of two species: a strong and a weak one, competing for a single food resource. The inclusion of a term corresponding to intraspecies competition, in particular for the strong species, shows that, it a certain threshold value is overcome, the classical result on extinction and coexistence of Lotka-Volterra type equations can drastically change yielding a kind of phase-transition to a coexistence phase. (author). 18 refs, 2 figs

Costs of coexistence along a gradient of competitor densities: an experiment with arvicoline rodents.

Science.gov (United States)

Eccard, Jana A; Ylönen, Hannu

2007-01-01

1. Costs of coexistence for species with indirect resource competition usually increase monotonically with competitor numbers. Very little is known though about the shape of the cost function for species with direct interference competition. 2. Here we report the results of an experiment with two vole species in artificial coexistence in large enclosures, where density of the dominant competitor species (Microtus agrestis) was manipulated. Experimental populations of the subordinate vole species (Clethrionomys glareolus) were composed of same aged individuals to study distribution of costs of coexistence with a dominant species within an age-cohort. 3. Survival and space use decreased gradually with increasing field vole numbers. Thus, responses to interference competition in our system appeared to be similar as expected from resource competition. The total number of breeders was stable. Reproductive characteristics such as the timing of breeding, and the litter size were not affected. In the single species enclosures a proportion of surviving individuals were not able to establish a breeding territory against stronger conspecifics. Under competition with heterospecifics such nonbreeders suffered high mortality, whereas the breeders survived. 4. Combined interference of dominant conspecifics and heterospecifics probably increased the frequency of aggressive interactions, social stress and mortality for the weaker individuals within a homogeneous age cohort of the subordinate competitor population. 5. Our results suggest, that in open systems where bank voles are outcompeted over the breeding season by faster reproducing field voles, animals able to establish a territory may be able to withstand competitor pressure, while nonbreeding bank vole individuals are forced to emigrate to suboptimal forest habitats.

Hierarchical Learning of Tree Classifiers for Large-Scale Plant Species Identification.

Science.gov (United States)

Fan, Jianping; Zhou, Ning; Peng, Jinye; Gao, Ling

2015-11-01

In this paper, a hierarchical multi-task structural learning algorithm is developed to support large-scale plant species identification, where a visual tree is constructed for organizing large numbers of plant species in a coarse-to-fine fashion and determining the inter-related learning tasks automatically. For a given parent node on the visual tree, it contains a set of sibling coarse-grained categories of plant species or sibling fine-grained plant species, and a multi-task structural learning algorithm is developed to train their inter-related classifiers jointly for enhancing their discrimination power. The inter-level relationship constraint, e.g., a plant image must first be assigned to a parent node (high-level non-leaf node) correctly if it can further be assigned to the most relevant child node (low-level non-leaf node or leaf node) on the visual tree, is formally defined and leveraged to learn more discriminative tree classifiers over the visual tree. Our experimental results have demonstrated the effectiveness of our hierarchical multi-task structural learning algorithm on training more discriminative tree classifiers for large-scale plant species identification.

Plant-soil feedbacks and the coexistence of competing plants

NARCIS (Netherlands)

Revilla Rimbach, Tomas; Veen, G. F. (Ciska); Eppinga, Maarten B.; Weissing, Franz J.

Plant-soil feedbacks can have important implications for the interactions among plants. Understanding these effects is a major challenge since it is inherently difficult to measure and manipulate highly diverse soil communities. Mathematical models may advance this understanding by making the

Site fidelity by bees drives pollination facilitation in sequentially blooming plant species.

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Ogilvie, Jane E; Thomson, James D

2016-06-01

Plant species can influence the pollination and reproductive success of coflowering neighbors that share pollinators. Because some individual pollinators habitually forage in particular areas, it is also possible that plant species could influence the pollination of neighbors that bloom later. When flowers of a preferred forage plant decline in an area, site-fidelity may cause individual flower feeders to stay in an area and switch plant species rather than search for preferred plants in a new location. A newly blooming plant species may quickly inherit a set of visitors from a prior plant species, and therefore experience higher pollination success than it would in an area where the first species never bloomed. To test this, we manipulated the placement and timing of two plant species, Delphinium barbeyi and later-blooming Gentiana parryi. We recorded the responses of individually marked bumble bee pollinators. About 63% of marked individuals returned repeatedly to the same areas to forage on Delphinium. When Delphinium was experimentally taken out of bloom, most of those site-faithful individuals (78%) stayed and switched to Gentiana. Consequently, Gentiana flowers received more visits in areas where Delphinium had previously flowered, compared to areas where Delphinium was still flowering or never occurred. Gentiana stigmas received more pollen in areas where Delphinium disappeared than where it never bloomed, indicating that Delphinium increases the pollination of Gentiana when they are separated in time. Overall, we show that individual bumble bees are often site-faithful, causing one plant species to increase the pollination of another even when separated in time, which is a novel mechanism of pollination facilitation.

Arthropod assemblages on native and nonnative plant species of a coastal reserve in California.

Science.gov (United States)

Fork, Susanne K

2010-06-01

Biological invasions by nonnative plant species are a widespread phenomenon. Many studies have shown strong ecological impacts of plant invasions on native plant communities and ecosystem processes. Far fewer studies have examined effects on associated animal communities. From the perspective of a reserve's land management, I addressed the question of whether arthropod assemblages on two nonnative plant species of concern were impoverished compared with those assemblages associated with two predominant native plant species of that reserve. If the nonnative plant species, Conium maculatum L., and Phalaris aquatica L., supported highly depauperate arthropod assemblages compared with the native plant species, Baccharis pilularis De Candolle and Leymus triticoides (Buckley) Pilger, this finding would provide additional support for prioritizing removal of nonnatives and restoration of natives. I assessed invertebrate assemblages at the taxonomic levels of arthropod orders, Coleoptera families, and Formicidae species, using univariate analyses to examine community attributes (richness and abundance) and multivariate techniques to assess arthropod assemblage community composition differences among plant species. Arthropod richness estimates by taxonomic level between native and nonnative vegetation showed varying results. Overall, arthropod richness of the selected nonnative plants, examined at higher taxonomic resolution, was not necessarily less diverse than two of common native plants found on the reserve, although differences were found among plant species. Impacts of certain nonnative plant species on arthropod assemblages may be more difficult to elucidate than those impacts shown on native plants and ecosystem processes.

Plant species richness regulates soil respiration through changes in productivity.

Science.gov (United States)

Dias, André Tavares Corrêa; van Ruijven, Jasper; Berendse, Frank

2010-07-01

Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of diversity on soil respiration. We hypothesized that plant diversity could affect soil respiration in two ways. On the one hand, more diverse plant communities have been shown to promote plant productivity, which could increase soil respiration. On the other hand, the nutrient concentration in the biomass produced has been shown to decrease with diversity, which could counteract the production-induced increase in soil respiration. Our results clearly show that soil respiration increased with species richness. Detailed analysis revealed that this effect was not due to differences in species composition. In general, soil respiration in mixtures was higher than would be expected from the monocultures. Path analysis revealed that species richness predominantly regulates soil respiration through changes in productivity. No evidence supporting the hypothesized negative effect of lower N concentration on soil respiration was found. We conclude that shifts in productivity are the main mechanism by which changes in plant diversity may affect soil respiration.

When Are Native Species Inappropriate for Conservation Plantings

Science.gov (United States)

Conservation agencies and organizations are generally reluctant to encourage the use of invasive plant species in conservation programs. Harsh lessons learned in the past have resulted in tougher screening protocols for non-indigenous species introductions and removal of many no...

Links between plant litter chemistry, species diversity, and below-ground ecosystem function.

Science.gov (United States)

Meier, Courtney L; Bowman, William D

2008-12-16

Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics of plant species diversity. We amended native soils with litter mixtures containing up to 4 alpine plant species, and we used 9 litter chemical traits to evaluate the chemical composition (i.e., the identity and quantity of compounds) and chemical diversity of the litter mixtures. The chemical composition of the litter mixtures was the strongest predictor of soil respiration, net N mineralization, and microbial biomass N. Soil respiration and net N mineralization rates were also significantly correlated with the chemical diversity of the litter mixtures. In contrast, soil C and N cycling rates were poorly correlated with plant species richness, and there was no relationship between species richness and the chemical diversity of the litter mixtures. These results indicate that the composition and diversity of chemical compounds in litter are potentially important functional traits affecting decomposition, and simple metrics like plant species richness may fail to capture variation in these traits. Litter chemical traits therefore provide a mechanistic link between organisms, species diversity, and key components of below-ground ecosystem function.

Developing a taxonomic identification system of Phytophthora species based on microsatellites.

Science.gov (United States)

del Castillo-Múnera, Johanna; Cárdenas, Martha; Pinzón, Andrés; Castañeda, Adriana; Bernal, Adriana J; Restrepo, Silvia

2013-01-01

Phytophthora is the most important genus of the Oomycete plant pathogens. Nowadays, there are 117 described species in this genus, most of them being primary invaders of plant tissues. The different species are causal agents of diseases in a wide range of crops and plants in natural environments. In order to develop control strategies against Phytophthoraspecies, it is important to know the biology, ecology and evolutionary processes of these important pathogens. The aim of this study was to propose and validate a low cost identification system for Phytophthora species based on a set of polymorphic microsatellite (SSRs) markers. Thirty-three isolates representing Phytophthora infestans, Phytophthora andina, Phytophthora sojae, Phytophthora cryptogea, Phytophthora nicotianae, Phytophthora capsici and Phytophthora cinnamomi species were obtained, and 13 SSRs were selected as potentially transferable markers between these species. Amplification conditions, including annealing temperatures, were standardized for several markers. A subset of these markers amplified in all species, showing species-specific alleles. The adaptability and impact of the identification system in Colombia, an Andean agricultural country where different Phytophthora species co-exist in the same or in several hosts grown together, are discussed. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

The Fluctuation Niche in Plants

Directory of Open Access Journals (Sweden)

Jaume Terradas

2009-01-01

Full Text Available Classical approaches to niche in coexisting plants have undervalued temporal fluctuations. We propose that fluctuation niche is an important dimension of the total niche and interacts with habitat and life-history niches to provide a better understanding of the multidimensional niche space where ecological interactions occur. To scale a fluctuation niche, it is necessary to relate environmental constrictions or species performance not only to the absolute values of the usual environmental and ecophysiological variables but also to their variances or other measures of variability. We use Mediterranean plant communities as examples, because they present characteristic large seasonal and interannual fluctuations in water and nutrient availabilities, along an episodic-constant gradient, and because the plant responses include a number of syndromes coupled to this gradient.

The Fluctuation Niche in Plants

International Nuclear Information System (INIS)

Terradas, J.; Penuelas, J.; Lloret, F.; Penuelas, J.

2009-01-01

Classical approaches to niche in coexisting plants have undervalued temporal fluctuations. We propose that fluctuation niche is an important dimension of the total niche and interacts with habitat and life-history niches to provide a better understanding of the multidimensional niche space where ecological interactions occur. To scale a fluctuation niche, it is necessary to relate environmental constrictions or species performance not only to the absolute values of the usual environmental and eco physiological variables but also to their variances or other measures of variability. We use Mediterranean plant communities as examples, because they present characteristic large seasonal and inter annual fluctuations in water and nutrient availabilities, along an episodic-constant gradient, and because the plant responses include a number of syndromes coupled to this gradient.

Support Vector Machine Based Tool for Plant Species Taxonomic Classification

OpenAIRE

Manimekalai .K; Vijaya.MS

2014-01-01

Plant species are living things and are generally categorized in terms of Domain, Kingdom, Phylum, Class, Order, Family, Genus and name of Species in a hierarchical fashion. This paper formulates the taxonomic leaf categorization problem as the hierarchical classification task and provides a suitable solution using a supervised learning technique namely support vector machine. Features are extracted from scanned images of plant leaves and trained using SVM. Only class, order, family of plants...

Does resource availability, resource heterogeneity or species turnover mediate changes in plant species richness in grazed grasslands?

NARCIS (Netherlands)

Bakker, C; Blair, JM; Knapp, AK

2003-01-01

Grazing by large ungulates often increases plant species richness in grasslands of moderate to high productivity. In a mesic North American grassland with and without the presence of bison (Bos bison), a native ungulate grazer, three non-exclusive hypotheses for increased plant species richness in

A regional approach to plant DNA barcoding provides high species resolution of sedges (Carex and Kobresia, Cyperaceae) in the Canadian Arctic Archipelago.

Science.gov (United States)

Clerc-Blain, Jessica L E; Starr, Julian R; Bull, Roger D; Saarela, Jeffery M

2010-01-01

Previous research on barcoding sedges (Carex) suggested that basic searches within a global barcoding database would probably not resolve more than 60% of the world's some 2000 species. In this study, we take an alternative approach and explore the performance of plant DNA barcoding in the Carex lineage from an explicitly regional perspective. We characterize the utility of a subset of the proposed protein-coding and noncoding plastid barcoding regions (matK, rpoB, rpoC1, rbcL, atpF-atpH, psbK-psbI) for distinguishing species of Carex and Kobresia in the Canadian Arctic Archipelago, a clearly defined eco-geographical region representing 1% of the Earth's landmass. Our results show that matK resolves the greatest number of species of any single-locus (95%), and when combined in a two-locus barcode, it provides 100% species resolution in all but one combination (matK + atpFH) during unweighted pair-group method with arithmetic mean averages (UPGMA) analyses. Noncoding regions were equally or more variable than matK, but as single markers they resolve substantially fewer taxa than matK alone. When difficulties with sequencing and alignment due to microstructural variation in noncoding regions are also considered, our results support other studies in suggesting that protein-coding regions are more practical as barcoding markers. Plastid DNA barcodes are an effective identification tool for species of Carex and Kobresia in the Canadian Arctic Archipelago, a region where the number of co-existing closely related species is limited. We suggest that if a regional approach to plant DNA barcoding was applied on a global scale, it could provide a solution to the generally poor species resolution seen in previous barcoding studies. © 2009 Blackwell Publishing Ltd.

Feeding patterns of migratory and non-migratory fourth instar larvae of two coexisting Chaoborus species in an acidic and metal contaminated lake: Importance of prey ingestion rate in predicting metal bioaccumulation

Science.gov (United States)

Croteau, M.-N.; Hare, L.; Marcoux, P.

2003-01-01

We studied diel variations in the feeding habits and migratory behaviors of two coexisting Chaoborus species in an acidic and metal contaminated lake (Lake Turcotte, QC, Canada). We found that although the zooplankton community was dominated by rotifers, both Chaoborus species fed mostly on chironomids and crustaceans despite the relatively low abundance of these prey types in the lake plankton. Chaoborus americanus larvae fed on those of Chaoborus punctipennis, but not vice versa. The non-migratory species (C. americanus) fed throughout the day and night whereas the migratory species (C. punctipennis) fed only at night while in the water column. The larger-bodied C. americanus consumed more prey and had a more diverse diet than did the smaller-bodied C. punctipennis. Differences in feeding habits between the Chaoborus species inhabiting Lake Turcotte (prey biomass, prey types) likely explain in part their ability to coexist. Attempts to predict Cd in the Chaoborus species using our measurements of Cd in their prey and their prey ingestion rates met with mixed success; although we correctly predicted higher Cd concentrations for C. americanus larvae than for C. punctipennis larvae, we under-predicted absolute Cd concentrations. We suggest that studies such as ours that are based on analyses of gut contents of larvae collected at intervals of 4h or longer likely underestimate prey ingestion rates.

One Year in the Lower St. Lawrence Estuary: Feeding Niche Separation of Two Co-existing Krill Species

Science.gov (United States)

Winkler, G.; Cabrol, J.; Sage, R.; Nozais, C.; Tremblay, R.; Starr, M.

2016-02-01

The lower St. Lawrence estuary (LSLE) is influenced by river discharge and saltwater inflow. Together with arctic water inflow and ice cover in winter a strong stratification occurs resulting in a cold intermediate layer (CIL) from spring to autumn. This stratification provides thermal habitats. Here, we focus on two krill species Thysanoessa raschii and Meganyctiphanes norvegica that aggregate in the CIL and the warmer deep water layer, respectively. Both species are known to migrate into the surface layer to feed and thus transfering energy through the food web by linking lower with higher trophic levels. However, their specific feeding biology and trophic interactions are poorly understood. We tested the following hypotheses: (1) the diets vary throughout the season depending on food availability, (2) similar to thermal habitat separation, trophic niche separation between T. raschii and M. norvegica occurs, characterized by herbivory in T. raschii and carnivory in M. norvegica. Trophic position and feeding behavior of theses krill populations were monitored throughout one year 2014-2015 using a stable isotope approach. The two species showed a seasonal shift in their trophic position being on a higher trophic level in summer than in spring and autumn, which did not correspond to phytoplankton or zooplankton availability. Within the trophic space of carbon and nitrogen stable isotopes M. norvegica showed a relatively stable position, whereas T. raschii covered a much larger space throughout the year. M. norvegica was always positioned at a higher trophic level than T. raschii. Results of a stable isotope mixing model (SIAR) revealed 50% phytoplankton and 50% copepods in the diet of M. norvegica, while T. raschii showed a higher proportion of ca. 70% phytoplankton in its diet. Both species exploited several trophic levels, but in different proportions, thereby minimizing diet overlap, suggesting a further mechanism to enhance stable co-existence of these krill

Reciprocal effects of litter from exotic and congeneric native plant species via soil nutrients.

Directory of Open Access Journals (Sweden)

Annelein Meisner

Full Text Available Invasive exotic plant species are often expected to benefit exclusively from legacy effects of their litter inputs on soil processes and nutrient availability. However, there are relatively few experimental tests determining how litter of exotic plants affects their own growth conditions compared to congeneric native plant species. Here, we test how the legacy of litter from three exotic plant species affects their own performance in comparison to their congeneric natives that co-occur in the invaded habitat. We also analyzed litter effects on soil processes. In all three comparisons, soil with litter from exotic plant species had the highest respiration rates. In two out of the three exotic-native species comparisons, soil with litter from exotic plant species had higher inorganic nitrogen concentrations than their native congener, which was likely due to higher initial litter quality of the exotics. When litter from an exotic plant species had a positive effect on itself, it also had a positive effect on its native congener. We conclude that exotic plant species develop a legacy effect in soil from the invaded range through their litter inputs. This litter legacy effect results in altered soil processes that can promote both the exotic plant species and their native congener.

Molecular species composition of plant cardiolipin determined by liquid chromatography mass spectrometry

Science.gov (United States)

Zhou, Yonghong; Peisker, Helga

2016-01-01

Cardiolipin (CL), an anionic phospholipid of the inner mitochondrial membrane, provides essential functions for stabilizing respiratory complexes and is involved in mitochondrial morphogenesis and programmed cell death in animals. The role of CL and its metabolism in plants are less well understood. The measurement of CL in plants, including its molecular species composition, is hampered by the fact that CL is of extremely low abundance, and that plants contain large amounts of interfering compounds including galactolipids, neutral lipids, and pigments. We used solid phase extraction by anion exchange chromatography to purify CL from crude plant lipid extracts. LC/MS was used to determine the content and molecular species composition of CL. Thus, up to 23 different molecular species of CL were detected in different plant species, including Arabidopsis, mung bean, spinach, barley, and tobacco. Similar to animals, plant CL is dominated by highly unsaturated species, mostly containing linoleic and linolenic acid. During phosphate deprivation or exposure to an extended dark period, the amount of CL decreased in Arabidopsis, accompanied with an increased degree in unsaturation. The mechanism of CL remodeling during stress, and the function of highly unsaturated CL molecular species, remains to be defined. PMID:27179363

Radiocaesium accumulation by different plant species

International Nuclear Information System (INIS)

Filiptsova, G.G.

2000-01-01

Using the model object influence of mineral nutritions level on radiocaesium accumulation by different plant species has been studied. It was shown the wheat roots accumulation the minimal value on radiocaesium on normal potassium level, the rye roots accumulation maximal level radiocaesium. (authors)

Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

Directory of Open Access Journals (Sweden)

Astrid Welk

Full Text Available This study presents an experimental approach to assess the relative importance of climatic and biotic factors as determinants of species' geographical distributions. We asked to what extent responses of grassland plant species to biotic interactions vary with climate, and to what degree this variation depends on the species' biogeography. Using a gradient from oceanic to continental climate represented by nine common garden transplant sites in Germany, we experimentally tested whether congeneric grassland species of different geographic distribution (oceanic vs. continental plant range type responded differently to combinations of climate, competition and mollusc herbivory. We found the relative importance of biotic interactions and climate to vary between the different components of plant performance. While survival and plant height increased with precipitation, temperature had no effect on plant performance. Additionally, species with continental plant range type increased their growth in more benign climatic conditions, while those with oceanic range type were largely unable to take a similar advantage of better climatic conditions. Competition generally caused strong reductions of aboveground biomass and growth. In contrast, herbivory had minor effects on survival and growth. Against expectation, these negative effects of competition and herbivory were not mitigated under more stressful continental climate conditions. In conclusion we suggest variation in relative importance of climate and biotic interactions on broader scales, mediated via species-specific sensitivities and factor-specific response patterns. Our results have important implications for species distribution models, as they emphasize the large-scale impact of biotic interactions on plant distribution patterns and the necessity to take plant range types into account.

Disjunct populations of European vascular plant species keep the same climatic niches

DEFF Research Database (Denmark)

Wasof, Safaa; Lenoir, Jonathan; Aarrestad, Per Arild

2015-01-01

separated for thousands of years. Location: European Alps and Fennoscandia. Methods: Of the studied pool of 888 terrestrial vascular plant species occurring in both the Alps and Fennoscandia, we used two complementary approaches to test and quantify climatic-niche shifts for 31 species having strictly......Aim: Previous research on how climatic niches vary across species ranges has focused on a limited number of species, mostly invasive, and has not, to date, been very conclusive. Here we assess the degree of niche conservatism between distant populations of native alpine plant species that have been...... to be largely valid for arctic-alpine plants....

Vascular plant and vertebrate species richness in national parks of the eastern United States

Science.gov (United States)

Hatfield, Jeffrey S.; Myrick, Kaci E.; Huston, Michael A.; Weckerly, Floyd W.; Green, M. Clay

2013-01-01

Given the estimates that species diversity is diminishing at 50-100 times the normal rate, it is critical that we be able to evaluate changes in species richness in order to make informed decisions for conserving species diversity. In this study, we examined the potential of vascular plant species richness to be used as a surrogate for vertebrate species richness in the classes of amphibians, reptiles, birds, and mammals. Vascular plants, as primary producers, represent the biotic starting point for ecological community structure and are the logical place to start for understanding vertebrate species associations. We used data collected by the United States (US) National Park Service (NPS) on species presence within parks in the eastern US to estimate simple linear regressions between plant species richness and vertebrate richness. Because environmental factors may also influence species diversity, we performed simple linear regressions of species richness versus natural logarithm of park area, park latitude, mean annual precipitation, mean annual temperature, and human population density surrounding the parks. We then combined plant species richness and environmental variables in multiple regressions to determine the variables that remained as significant predictors of vertebrate species richness. As expected, we detected significant relationships between plant species richness and amphibian, bird, and mammal species richness. In some cases, plant species richness was predicted by park area alone. Species richness of mammals was only related to plant species richness. Reptile species richness, on the other hand, was related to plant species richness, park latitude and annual precipitation, while amphibian species richness was related to park latitude, park area, and plant species richness. Thus, plant species richness predicted species richness of different vertebrate groups to varying degrees and should not be used exclusively as a surrogate for vertebrate

Simulated geographic variations of plant species richness, evenness and abundance using climatic constraints on plant functional diversity

International Nuclear Information System (INIS)

Kleidon, Axel; Pavlick, Ryan; Reu, Bjoern; Adams, Jonathan

2009-01-01

Among the most pronounced large-scale geographic patterns of plant biodiversity are the increase in plant species richness towards the tropics, a more even distribution of the relative abundances of plant species in the tropics, and a nearly log-normal relative abundance distribution. Here we use an individual-based plant diversity model that relates climatic constraints to feasible plant growth strategies to show that all three basic diversity patterns can be predicted merely from the climatic constraints acting upon plant ecophysiological trade-offs. Our model predicts that towards objectively 'harsher' environments, the range of feasible growth strategies resulting in reproductive plants is reduced, thus resulting in lower functional plant species richness. The reduction of evenness is attributed to a more rapid decline in productivity from the most productive to less productive plant growth strategies since the particular setup of the strategy becomes more important in maintaining high productivity in harsher environments. This approach is also able to reproduce the increase in the deviation from a log-normal distribution towards more evenly distributed communities of the tropics. Our results imply that these general biodiversity relationships can be understood primarily by considering the climatic constraints on plant ecophysiological trade-offs.

Floristic summary of plant species in the air pollution literature.

Science.gov (United States)

Bennett, J P

1996-01-01

A floristic summary and analysis was performed on a list of the plant species that have been studied for the effects of gaseous and chemical air pollutants on vegetation in order to compare the species with the flora of North America north of Mexico. The scientific names of 2081 vascular plant species were extracted from almost 4000 journal articles stored in two large literature databases on the effects of air pollutants on plants. Three quarters of the plant species studied occur in North America, but this was only 7% of the total North American flora. Sixteen percent and 56% of all North American genera and families have been studied. The most studied genus is Pinus with 70% of the North American species studied, and the most studied family is the grass family, with 12% of the species studied. Although Pinus is ranked 86th in the North American flora, the grass family is ranked third, indicating that representation at the family level is better than at the genus level. All of the top ten families in North America are represented in the top 20 families in the air pollution effects literature, but only one genus (Lupinus) in the top ten genera in North America is represented in the top thirteen genera in the air pollution literature.

Coexistence for an Almost Periodic Predator-Prey Model with Intermittent Predation Driven by Discontinuous Prey Dispersal

Directory of Open Access Journals (Sweden)

Yantao Luo

2017-01-01

Full Text Available An almost periodic predator-prey model with intermittent predation and prey discontinuous dispersal is studied in this paper, which differs from the classical continuous and impulsive dispersal predator-prey models. The intermittent predation behavior of the predator species only happens in the channels between two patches where the discontinuous migration movement of the prey species occurs. Using analytic approaches and comparison theorems of the impulsive differential equations, sufficient criteria on the boundedness, permanence, and coexistence for this system are established. Finally, numerical simulations demonstrate that, for an intermittent predator-prey model, both the intermittent predation and intrinsic growth rates of the prey and predator species can greatly impact the permanence, extinction, and coexistence of the population.

Plant species classification using deep convolutional neural network

DEFF Research Database (Denmark)

Dyrmann, Mads; Karstoft, Henrik; Midtiby, Henrik Skov

2016-01-01

Information on which weed species are present within agricultural fields is important for site specific weed management. This paper presents a method that is capable of recognising plant species in colour images by using a convolutional neural network. The network is built from scratch trained an...

The Lion King and the Hyaena Queen: large carnivore interactions and coexistence.

Science.gov (United States)

Périquet, Stéphanie; Fritz, Hervé; Revilla, Eloy

2015-11-01

Interactions among species, which range from competition to facilitation, have profound effects on ecosystem functioning. Large carnivores are of particular importance in shaping community structure since they are at the top of the food chain, and many efforts are made to conserve such keystone species. Despite this, the mechanisms of carnivore interactions are far from understood, yet they are key to enabling or hindering their coexistence and hence are highly relevant for their conservation. The goal of this review is thus to provide detailed information on the extents of competition and facilitation between large carnivores and their impact in shaping their life histories. Here, we use the example of spotted hyaenas (Crocuta crocuta) and lions (Panthera leo) and provide a comprehensive knowledge of their interactions based on meta-analyses from available literature (148 publications). Despite their strong potential for both exploitation and interference competition (range and diet overlap, intraguild predation and kleptoparasitism), we underline some mechanisms facilitating their coexistence (different prey-age selection and scavenging opportunities). We stress the fact that prey abundance is key to their coexistence and that hyaenas forming very large groups in rich ecosystems could have a negative impact on lions. We show that the coexistence of spotted hyaenas and lions is a complex balance between competition and facilitation, and that prey availability within the ecosystem determines which predator is dominant. However, there are still many gaps in our knowledge such as the spatio-temporal dynamics of their interactions. As both species' survival becomes increasingly dependent on protected areas, where their densities can be high, it is critical to understand their interactions to inform both reintroduction programs and protected area management. © 2014 Cambridge Philosophical Society.

Fungal-host diversity among mycoheterotrophic plants increases proportionally to their fungal-host overlap.

Science.gov (United States)

Gomes, Sofia I F; Merckx, Vincent S F T; Saavedra, Serguei

2017-05-01

The vast majority of plants obtain an important proportion of vital resources from soil through mycorrhizal fungi. Generally, this happens in exchange of photosynthetically fixed carbon, but occasionally the interaction is mycoheterotrophic, and plants obtain carbon from mycorrhizal fungi. This process results in an antagonistic interaction between mycoheterotrophic plants and their fungal hosts. Importantly, the fungal-host diversity available for plants is restricted as mycoheterotrophic interactions often involve narrow lineages of fungal hosts. Unfortunately, little is known whether fungal-host diversity may be additionally modulated by plant-plant interactions through shared hosts. Yet, this may have important implications for plant competition and coexistence. Here, we use DNA sequencing data to investigate the interaction patterns between mycoheterotrophic plants and arbuscular mycorrhizal fungi. We find no phylogenetic signal on the number of fungal hosts nor on the fungal hosts shared among mycoheterotrophic plants. However, we observe a potential trend toward increased phylogenetic diversity of fungal hosts among mycoheterotrophic plants with increasing overlap in their fungal hosts. While these patterns remain for groups of plants regardless of location, we do find higher levels of overlap and diversity among plants from the same location. These findings suggest that species coexistence cannot be fully understood without attention to the two sides of ecological interactions.

Competition for light and nutrients in layered communities of aquatic plants.

Science.gov (United States)

van Gerven, Luuk P A; de Klein, Jeroen J M; Gerla, Daan J; Kooi, Bob W; Kuiper, Jan J; Mooij, Wolf M

2015-07-01

Dominance of free-floating plants poses a threat to biodiversity in many freshwater ecosystems. Here we propose a theoretical framework to understand this dominance, by modeling the competition for light and nutrients in a layered community of floating and submerged plants. The model shows that at high supply of light and nutrients, floating plants always dominate due to their primacy for light, even when submerged plants have lower minimal resource requirements. The model also shows that floating-plant dominance cannot be an alternative stable state in light-limited environments but only in nutrient-limited environments, depending on the plants' resource consumption traits. Compared to unlayered communities, the asymmetry in competition for light-coincident with symmetry in competition for nutrients-leads to fundamentally different results: competition outcomes can no longer be predicted from species traits such as minimal resource requirements ([Formula: see text] rule) and resource consumption. Also, the same two species can, depending on the environment, coexist or be alternative stable states. When applied to two common plant species in temperate regions, both the model and field data suggest that floating-plant dominance is unlikely to be an alternative stable state.

Plant species effects on soil nutrients and chemistry in arid ecological zones.

Science.gov (United States)

Johnson, Brittany G; Verburg, Paul S J; Arnone, John A

2016-09-01

The presence of vegetation strongly influences ecosystem function by controlling the distribution and transformation of nutrients across the landscape. The magnitude of vegetation effects on soil chemistry is largely dependent on the plant species and the background soil chemical properties of the site, but has not been well quantified along vegetation transects in the Great Basin. We studied the effects of plant canopy cover on soil chemistry within five different ecological zones, subalpine, montane, pinyon-juniper, sage/Mojave transition, and desert shrub, in the Great Basin of Nevada all with similar underlying geology. Although plant species differed in their effects on soil chemistry, the desert shrubs Sarcobatus vermiculatus, Atriplex spp., Coleogyne ramosissima, and Larrea tridentata typically exerted the most influence on soil chemistry, especially amounts of K(+) and total nitrogen, beneath their canopies. However, the extent to which vegetation affected soil nutrient status in any given location was not only highly dependent on the species present, and presumably the nutrient requirements and cycling patterns of the plant species, but also on the background soil characteristics (e.g., parent material, weathering rates, leaching) where plant species occurred. The results of this study indicate that the presence or absence of a plant species, especially desert shrubs, could significantly alter soil chemistry and subsequently ecosystem biogeochemistry and function.

7 CFR 650.22 - Rare, threatened, and endangered species of plants and animals.

Science.gov (United States)

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Rare, threatened, and endangered species of plants and... Related Environmental Concerns § 650.22 Rare, threatened, and endangered species of plants and animals. (a) Background. (1) A variety of plant and animal species of the United States are so reduced in numbers that...

Herbicides: an unexpected ally for native plants in the war against invasive species

Science.gov (United States)

Andrea Watts; Tim Harrington; Dave Peter

2015-01-01

Herbicides are primarily used for protecting agricultural crops from weeds and controlling vegetation competition in newly planted forest stands. Yet for over 40 years, they have also proven useful in controlling invasive plant species in natural areas. Nonnative invasive plant species, if not controlled, can displace native species and disrupt an ecosystem by changing...

Species diversity of plant communities from territories with natural origin radionuclides contamination

Energy Technology Data Exchange (ETDEWEB)

Kaneva, A.V.; Belykh, E.S.; Maystrenko, T.A.; Grusdev, B.I.; Zainullin, V.G.; Vakhrusheva, O.M. [Institute of Biology, Komi Scientific Center, Ural Division of RAS, Syktyvkar, 167982 (Russian Federation); Oughton, D. [Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Aas (Norway)

2014-07-01

Since plants dominate every landscape, the impact of any environmental stressor on plants can directly affect the structure and function of an ecosystem, resulting in decreased primary productivity and degradation of wildlife habitat. The investigation goal of the present research was to study how vascular plant species' composition at a former radium mining site could be related to i) soil contamination with heavy metals and uranium and thorium decay chain radionuclides and ii) soil agrochemical properties. Between the 1930's and 1950's, the commercial extraction of radium, storage of the uranium mill tailings and radium production wastes, together with deactivation of the site with a mixture of sand and gravel completely destroyed plant communities in the vicinity of Vodny settlement (Komi Republic, Russia). The plant cover recovery started more than 60 years ago, and resulted in overgrowing with common grassland plant species. Three meadow sites were investigated, one with low contamination (on the territory of former radium production plant), one with high contamination (waste storage cell) and a reference sites out of the radiochemical plant zone of influence, but with similar natural conditions. Geo-botanical descriptions revealed 134 vascular plant species from 34 families in the meadow communities studied. The greatest richness was seen for Poaceae, Asteraceae, Rosaceae and Fabaceae families; others had 1-5 species. The highest richness in diversity was seen at reference sites with 95 vascular plant species. 87 species were registered on low contaminated sites and 75 species on high contaminated. Perennial herbs were the dominant life form on all the studied meadow communities. Arboreal species expansion in vegetation was noted at both experimental and reference sites. Shannon index calculations indicated a significant (p<0.05) decrease in species diversity on sample areas of the highly contaminated radioactive waste storage cell. Mean values

Biology and occurrence of Inga Busk species (Lepidoptera: Oecophoridae) on Cerrado host plants.

Science.gov (United States)

Diniz, Ivone R; Bernardes, Carolina; Rodovalho, Sheila; Morais, Helena C

2007-01-01

We sampled Inga Busk species caterpillars weekly in the cerrado on 15 plants of Diospyros burchellii Hern. (Ebenaceae) from January 2002 to December 2003, on 30 plants of Caryocar brasiliense (Caryocaraceae) from July 2003 to June 2004, and since 1991 on several other plant species. In total we found 15 species of Inga on cerrado host plants. Nine species were very rare, with only one to five adults reared. The other six species occurred throughout the year, with higher abundance during the dry season, from May to July, coinciding with overall peaks of caterpillar abundance in the cerrado. Caterpillars of the genus Inga build shelters by tying and lining two mature or old leaves with silk and frass, where they rest and develop (a common habit found in Oecophorinae). The final instar builds a special envelope inside the leaf shelter, where it will complete the larval stage and pupate. The species are very difficult to distinguish in the immature stages. External features were useful in identifying only four species: I. haemataula (Meyrick), I. phaecrossa (Meyrick), I. ancorata (Walsingham), and I. corystes (Meyrick). These four species are polyphagous and have wide geographical distributions. In this paper we provide information on the natural history and host plants of six Inga species common on cerrado host plants, for which there are no reports in the literature.

Mapping paddy rice planting area in rice-wetland coexistent areas through analysis of Landsat 8 OLI and MODIS images.

Science.gov (United States)

Zhou, Yuting; Xiao, Xiangming; Qin, Yuanwei; Dong, Jinwei; Zhang, Geli; Kou, Weili; Jin, Cui; Wang, Jie; Li, Xiangping

2016-04-01

Accurate and up-to-date information on the spatial distribution of paddy rice fields is necessary for the studies of trace gas emissions, water source management, and food security. The phenology-based paddy rice mapping algorithm, which identifies the unique flooding stage of paddy rice, has been widely used. However, identification and mapping of paddy rice in rice-wetland coexistent areas is still a challenging task. In this study, we found that the flooding/transplanting periods of paddy rice and natural wetlands were different. The natural wetlands flood earlier and have a shorter duration than paddy rice in the Panjin Plain, a temperate region in China. We used this asynchronous flooding stage to extract the paddy rice planting area from the rice-wetland coexistent area. MODIS Land Surface Temperature (LST) data was used to derive the temperature-defined plant growing season. Landsat 8 OLI imagery was used to detect the flooding signal and then paddy rice was extracted using the difference in flooding stages between paddy rice and natural wetlands. The resultant paddy rice map was evaluated with in-situ ground-truth data and Google Earth images. The estimated overall accuracy and Kappa coefficient were 95% and 0.90, respectively. The spatial pattern of OLI-derived paddy rice map agrees well with the paddy rice layer from the National Land Cover Dataset from 2010 (NLCD-2010). The differences between Rice Landsat and Rice NLCD are in the range of ±20% for most 1-km grid cell. The results of this study demonstrate the potential of the phenology-based paddy rice mapping algorithm, via integrating MODIS and Landsat 8 OLI images, to map paddy rice fields in complex landscapes of paddy rice and natural wetland in the temperate region.

Postglacial migration supplements climate in determining plant species ranges in Europe

Science.gov (United States)

Normand, Signe; Ricklefs, Robert E.; Skov, Flemming; Bladt, Jesper; Tackenberg, Oliver; Svenning, Jens-Christian

2011-01-01

The influence of dispersal limitation on species ranges remains controversial. Considering the dramatic impacts of the last glaciation in Europe, species might not have tracked climate changes through time and, as a consequence, their present-day ranges might be in disequilibrium with current climate. For 1016 European plant species, we assessed the relative importance of current climate and limited postglacial migration in determining species ranges using regression modelling and explanatory variables representing climate, and a novel species-specific hind-casting-based measure of accessibility to postglacial colonization. Climate was important for all species, while postglacial colonization also constrained the ranges of more than 50 per cent of the species. On average, climate explained five times more variation in species ranges than accessibility, but accessibility was the strongest determinant for one-sixth of the species. Accessibility was particularly important for species with limited long-distance dispersal ability, with southern glacial ranges, seed plants compared with ferns, and small-range species in southern Europe. In addition, accessibility explained one-third of the variation in species' disequilibrium with climate as measured by the realized/potential range size ratio computed with niche modelling. In conclusion, we show that although climate is the dominant broad-scale determinant of European plant species ranges, constrained dispersal plays an important supplementary role. PMID:21543356

Minimizing Risks of Invasive Alien Plant Species in Tropical Production Forest Management

Directory of Open Access Journals (Sweden)

Michael Padmanaba

2014-08-01

Full Text Available Timber production is the most pervasive human impact on tropical forests, but studies of logging impacts have largely focused on timber species and vertebrates. This review focuses on the risk from invasive alien plant species, which has been frequently neglected in production forest management in the tropics. Our literature search resulted in 114 publications with relevant information, including books, book chapters, reports and papers. Examples of both invasions by aliens into tropical production forests and plantation forests as sources of invasions are presented. We discuss species traits and processes affecting spread and invasion, and silvicultural practices that favor invasions. We also highlight potential impacts of invasive plant species and discuss options for managing them in production forests. We suggest that future forestry practices need to reduce the risks of plant invasions by conducting surveillance for invasive species; minimizing canopy opening during harvesting; encouraging rapid canopy closure in plantations; minimizing the width of access roads; and ensuring that vehicles and other equipment are not transporting seeds of invasive species. Potential invasive species should not be planted within dispersal range of production forests. In invasive species management, forewarned is forearmed.

Plant species influence on soil C after afforestation of Mediterranean degraded soils

Science.gov (United States)

Dominguez, Maria T.; García-Vargas, Carlos; Madejón, Engracia; Marañón, Teodoro

2015-04-01

Increasing C sequestration in terrestrial ecosystems is one of the main current environmental challenges to mitigate climate change. Afforestation of degraded and contaminated lands is one of the key strategies to achieve an increase in C sequestration in ecosystems. Plant species differ in their mechanisms of C-fixation, C allocation into different plant organs, and interaction with soil microorganisms, all these factors influencing the dynamics of soil C following the afforestation of degraded soils. In this work we examine the influence of different woody plant species on soil C dynamics in degraded and afforested Mediterranean soils. The soils were former agricultural lands that were polluted by a mining accident and later afforested with different native plant species. We analysed the effect of four of these species (Olea europaea var. sylvestris Brot., Populus alba L., Pistacia lentiscus L. and Retama sphaerocarpa (L.) Boiss.) on different soil C fractions, soil nutrient availability, microbial activity (soil enzyme activities) and soil CO2 fluxes 15 years after the establishment of the plantations. Results suggest that the influence of the planted trees and shrubs is still limited, being more pronounced in the more acidic and nutrient-poor soils. Litter accumulation varied among species, with the highest C accumulated in the litter under the deciduous species (Populus alba L.). No differences were observed in the amount of total soil organic C among the studied species, or in the concentrations of phenols and sugars in the dissolved organic C (DOC), which might have indicated differences in the biodegradability of the DOC. Microbial biomass and activity was highly influenced by soil pH, and plant species had a significant influence on soil pH in the more acidic site. Soil CO2 fluxes were more influenced by the plant species than total soil C content. Our results suggest that changes in total soil C stocks after the afforestation of degraded Mediterranean

Public attitude in the city of Belgrade towards invasive alien plant species

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Tomićević Jelena

2012-01-01

Full Text Available Biological invasions are seen as a major threat to biodiversity at a global level, while the number of new invasions is increasing at an alarming rate. Raising the awareness of the public, academic world and policy makers about the dangers caused by invasive species, is essential for the creation of the support needed to implement and coordinate the policies necessary to address this problem. The aim of this study is to determine the level of local public awareness of the existence of these plant species, examine the public attitude towards alien invasive plant species and willingness to get involved in the prevention of their spreading. The survey was conducted in four nurseries on the territory of the City of Belgrade and the investigation dealt only with alien invasive woody plant species. Thirty customers were questioned in each of the four nurseries. The results show that local public is uninformed on the issue of invasive plant species. It is necessary to constantly and intensively raise their awareness of this issue, as well as the awareness of harmful consequences that may occur due to the uncontrolled spreading of alien invasive species. This refers not only to the population that visits the nurseries and buys the plants there and to those employed in plant production and selling, but also to the whole local public and decision makers.

Small mammals as indicators of cryptic plant species diversity in the central Chilean plant endemicity hotspot

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Meredith Root-Bernstein

2014-12-01

Full Text Available Indicator species could help to compensate for a shortfall of knowledge about the diversity and distributions of undersampled and cryptic species. This paper provides background knowledge about the ecological interactions that affect and are affected by herbaceous diversity in central Chile, as part of the indicator species selection process. We focus on the ecosystem engineering role of small mammals, primarily the degu Octodon degus. We also consider the interacting effects of shrubs, trees, avian activity, livestock, slope, and soil quality on herbaceous communities in central Chile. We sampled herbaceous diversity on a private landholding characterized by a mosaic of savanna, grassland and matorral, across a range of degu disturbance intensities. We find that the strongest factors affecting endemic herbaceous diversity are density of degu runways, shrub cover and avian activity. Our results show that the degu, a charismatic and easily identifiable and countable species, could be used as an indicator species to aid potential conservation actions such as private protected area uptake. We map areas in central Chile where degus may indicate endemic plant diversity. This area is larger than expected, and suggests that significant areas of endemic plant communities may still exist, and should be identified and protected. Keywords: Cryptic species, Diversity, Endemic, Indicator species, Octodon degus, Plant

Cryptic Plutella species show deep divergence despite the capacity to hybridize.

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Perry, Kym D; Baker, Gregory J; Powis, Kevin J; Kent, Joanne K; Ward, Christopher M; Baxter, Simon W

2018-05-29

Understanding genomic and phenotypic diversity among cryptic pest taxa has important implications for the management of pests and diseases. The diamondback moth, Plutella xylostella L., has been intensively studied due to its ability to evolve insecticide resistance and status as the world's most destructive pest of brassicaceous crops. The surprise discovery of a cryptic species endemic to Australia, Plutella australiana Landry & Hebert, raised questions regarding the distribution, ecological traits and pest status of the two species, the capacity for gene flow and whether specific management was required. Here, we collected Plutella from wild and cultivated brassicaceous plants from 75 locations throughout Australia and screened 1447 individuals to identify mtDNA lineages and Wolbachia infections. We genotyped genome-wide SNP markers using RADseq in coexisting populations of each species. In addition, we assessed reproductive compatibility in crossing experiments and insecticide susceptibility phenotypes using bioassays. The two Plutella species coexisted on wild brassicas and canola crops, but only 10% of Plutella individuals were P. australiana. This species was not found on commercial Brassica vegetable crops, which are routinely sprayed with insecticides. Bioassays found that P. australiana was 19-306 fold more susceptible to four commonly-used insecticides than P. xylostella. Laboratory crosses revealed that reproductive isolation was incomplete but directionally asymmetric between the species. However, genome-wide nuclear SNPs revealed striking differences in genetic diversity and strong population structure between coexisting wild populations of each species. Nuclear diversity was 1.5-fold higher in P. australiana, yet both species showed limited variation in mtDNA. Infection with a single Wolbachia subgroup B strain was fixed in P. australiana, suggesting that a selective sweep contributed to low mtDNA diversity, while a subgroup A strain infected just 1

Root-associated fungal communities in three Pyroleae species and their mycobiont sharing with surrounding trees in subalpine coniferous forests on Mount Fuji, Japan.

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Jia, Shuzheng; Nakano, Takashi; Hattori, Masahira; Nara, Kazuhide

2017-11-01

Pyroleae species are perennial understory shrubs, many of which are partial mycoheterotrophs. Most fungi colonizing Pyroleae roots are ectomycorrhizal (ECM) and share common mycobionts with their Pyroleae hosts. However, such mycobiont sharing has neither been examined in depth before nor has the interspecific variation in sharing among Pyroleae species. Here, we examined root-associated fungal communities in three co-existing Pyroleae species, including Pyrola alpina, Pyrola incarnata, and Orthilia secunda, with reference to co-existing ECM fungi on the surrounding trees in the same soil blocks in subalpine coniferous forests. We identified 42, 75, and 18 fungal molecular operational taxonomic units in P. alpina, P. incarnata, and O. secunda roots, respectively. Mycobiont sharing with surrounding trees, which was defined as the occurrence of the same mycobiont between Pyroleae and surrounding trees in each soil block, was most frequent among P. incarnata (31 of 44 plants). In P. alpina, sharing was confirmed in 12 of 37 plants, and the fungal community was similar to that of P. incarnata. Mycobiont sharing was least common in O. secunda, found in only 5 of 32 plants. Root-associated fungi of O. secunda were dominated by Wilcoxina species, which were absent from the surrounding ECM roots in the same soil blocks. These results indicate that mycobiont sharing with surrounding trees does not equally occur among Pyroleae plants, some of which may develop independent mycorrhizal associations with ECM fungi, as suggested in O. secunda at our research sites.

Evaluating complementary networks of restoration plantings for landscape-scale occurrence of temporally dynamic species.

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Ikin, Karen; Tulloch, Ayesha; Gibbons, Philip; Ansell, Dean; Seddon, Julian; Lindenmayer, David

2016-10-01

Multibillion dollar investments in land restoration make it critical that conservation goals are achieved cost-effectively. Approaches developed for systematic conservation planning offer opportunities to evaluate landscape-scale, temporally dynamic biodiversity outcomes from restoration and improve on traditional approaches that focus on the most species-rich plantings. We investigated whether it is possible to apply a complementarity-based approach to evaluate the extent to which an existing network of restoration plantings meets representation targets. Using a case study of woodland birds of conservation concern in southeastern Australia, we compared complementarity-based selections of plantings based on temporally dynamic species occurrences with selections based on static species occurrences and selections based on ranking plantings by species richness. The dynamic complementarity approach, which incorporated species occurrences over 5 years, resulted in higher species occurrences and proportion of targets met compared with the static complementarity approach, in which species occurrences were taken at a single point in time. For equivalent cost, the dynamic complementarity approach also always resulted in higher average minimum percent occurrence of species maintained through time and a higher proportion of the bird community meeting representation targets compared with the species-richness approach. Plantings selected under the complementarity approaches represented the full range of planting attributes, whereas those selected under the species-richness approach were larger in size. Our results suggest that future restoration policy should not attempt to achieve all conservation goals within individual plantings, but should instead capitalize on restoration opportunities as they arise to achieve collective value of multiple plantings across the landscape. Networks of restoration plantings with complementary attributes of age, size, vegetation structure, and

Does enemy damage vary across the range of exotic plant species? Evidence from two coastal dune plant species in eastern Australia.

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Tabassum, Samiya; Leishman, Michelle R

2018-02-01

Release from natural enemies is often cited as a key factor for understanding the success of invasive plant species in novel environments. However, with time invasive species will accumulate native enemies in their invaded range, with factors such as spread distance from the site of introduction, climate and leaf-level traits potentially affecting enemy acquisition rates. However, the influence of such factors is difficult to assess without examining enemy attack across the entire species' range. We tested the significance of factors associated with range expansion (distance from source population and maximum population density), climatic variables (annual temperature and rainfall) and leaf-level traits [specific leaf area (SLA) and foliar nitrogen concentration] in explaining variation in enemy damage across multiple populations of two coastal invasive plants (Gladiolus gueinzii Kunze and Hydrocotyle bonariensis Lam.) along their entire introduced distribution in eastern Australia. We found that for H. bonariensis, amount of foliar damage increased with distance from source population. In contrast, for G. gueinzii, probability and amount of foliar damage decreased with decreasing temperature and increasing rainfall, respectively. Our results show that patterns of enemy attack across species' ranges are complex and cannot be generalised between species or even range edges.

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

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Mmoto L. Masubelele

2009-09-01

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.

Dynamics of an ant-plant-pollinator model

Science.gov (United States)

Wang, Yuanshi; DeAngelis, Donald L.; Nathaniel Holland, J.

2015-03-01

In this paper, we consider plant-pollinator-ant systems in which plant-pollinator interaction and plant-ant interaction are both mutualistic, but there also exists interference of pollinators by ants. The plant-pollinator interaction can be described by a Beddington-DeAngelis formula, so we extend the formula to characterize plant-pollinator mutualisms, including the interference by ants, and form a plant-pollinator-ant model. Using dynamical systems theory, we show uniform persistence of the model. Moreover, we demonstrate conditions under which boundary equilibria are globally asymptotically stable. The dynamics exhibit mechanisms by which the three species could coexist when ants interfere with pollinators. We define a threshold in ant interference. When ant interference is strong, it can drive plant-pollinator mutualisms to extinction. Furthermore, if the ants depend on pollination mutualism for their persistence, then sufficiently strong ant interference could lead to their own extinction as well. Yet, when ant interference is weak, plant-ant and plant-pollinator mutualisms can promote the persistence of one another.

Different tolerances of symbiotic and nonsymbiotic ant-plant networks to species extinctions

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Wesley Dattilo

2012-12-01

Full Text Available The knowledge of the mechanisms that shape biodiversity-stability relationships is essential to understand ecological and evolutionary dynamics of interacting species. However, most studies focus only on species loss and ignore the loss of interactions. In this study, I evaluated the topological structure of two different ant-plant networks: symbiotic (ants and myrmecophytes and nonsymbiotic (ants and plants with extrafloral nectaries. Moreover, I also evaluated in both networks the tolerance to plant and ant species extinction using a new approach. For this, I used models based on simulations of cumulative removals of species from the network at random. Both networks were fundamentally different in the interaction and extinction patterns. The symbiotic network was more specialized and less robust to species extinction. On the other hand, the nonsymbiotic network tends to be functionally redundant and more robust to species extinction. The difference for food resource utilization and ant nesting in both ant-plant interactions can explain the observed pattern. In short, I contributed in this manner to our understanding of the biodiversity maintenance and coevolutionary processes in facultative and obligate mutualisms.

Productivity of selected plant species adapted to arid regions. [Crassulacean metabolizing plants; Agave deserti and Ferocactus acanthodes

Energy Technology Data Exchange (ETDEWEB)

Nobel, P.S.

1980-01-01

The biomass potential of selected arid region species for alcohol production merits careful consideration. The basis for this interest is the current low agronomic use of arid lands and the potential productivity of certain species adapted to these lands. Plants displaying Crassulacean acid metabolism (CAM) are particularly interesting with reference to biomass for fuel in regions with low rainfall, because plants with this photosynthetic process are strikingly efficient in water requirements. For CAM plants, CO/sub 2/ fixation occurs primarily at night, when tissue surface temperature and hence transpirational water loss is less than daytime values. For Agave deserti in the Sonoran desert, the water-use efficiency (mass of CO/sub 2/ fixed/mass of water transpired) over an entire year is an order of magnitude or more larger than for C-3 and C-4 plants. This indicates how well adapted CAM species are to arid regions. The potential productivity per unit land area of CAM plants is fairly substantial and, therefore, of considerable economic interest for arid areas where growth of agricultural plants is minimal.

Plant-soil interactions in the expansion and native range of a poleward shifting plant species

NARCIS (Netherlands)

Grunsven, van R.H.A.; Putten, van der W.H.; Bezemer, T.M.; Berendse, F.; Veenendaal, E.M.

2010-01-01

Climate warming causes range shifts of many species toward higher latitudes and altitudes. However, range shifts of host species do not necessarily proceed at the same rates as those of their enemies and symbionts. Here, we examined how a range shifting plant species performs in soil from its

Intransitive competition is widespread in plant communities and maintains their species richness.

Science.gov (United States)

Soliveres, Santiago; Maestre, Fernando T; Ulrich, Werner; Manning, Peter; Boch, Steffen; Bowker, Matthew A; Prati, Daniel; Delgado-Baquerizo, Manuel; Quero, José L; Schöning, Ingo; Gallardo, Antonio; Weisser, Wolfgang; Müller, Jörg; Socher, Stephanie A; García-Gómez, Miguel; Ochoa, Victoria; Schulze, Ernst-Detlef; Fischer, Markus; Allan, Eric

2015-08-01

Intransitive competition networks, those in which there is no single best competitor, may ensure species coexistence. However, their frequency and importance in maintaining diversity in real-world ecosystems remain unclear. We used two large data sets from drylands and agricultural grasslands to assess: (1) the generality of intransitive competition, (2) intransitivity-richness relationships and (3) effects of two major drivers of biodiversity loss (aridity and land-use intensification) on intransitivity and species richness. Intransitive competition occurred in > 65% of sites and was associated with higher species richness. Intransitivity increased with aridity, partly buffering its negative effects on diversity, but was decreased by intensive land use, enhancing its negative effects on diversity. These contrasting responses likely arise because intransitivity is promoted by temporal heterogeneity, which is enhanced by aridity but may decline with land-use intensity. We show that intransitivity is widespread in nature and increases diversity, but it can be lost with environmental homogenisation. © 2015 John Wiley & Sons Ltd/CNRS.

Adaptive Management Plan for Sensitive Plant Species on the Nevada Test Site

International Nuclear Information System (INIS)

Wills, C. A.

2001-01-01

The Nevada Test Site supports numerous plant species considered sensitive because of their past or present status under the Endangered Species Act and with federal and state agencies. In 1998, the U.S. Department of Energy, Nevada Operation Office (DOE/NV) prepared a Resource Management Plan which commits to protects and conserve these sensitive plant species and to minimize accumulative impacts to them. This document presents the procedures of a long-term adaptive management plan which is meant to ensure that these goals are met. It identifies the parameters that are measured for all sensitive plant populations during long-term monitoring and the adaptive management actions which may be taken if significant threats to these populations are detected. This plan does not, however, identify the current list of sensitive plant species know to occur on the Nevada Test Site. The current species list and progress on their monitoring is reported annually by DOE/NV in the Resource Management Plan

Climate change has indirect effects on resource use and overlap among coexisting bird species with negative consequences for their reproductive success.

Science.gov (United States)

Auer, Sonya K; Martin, Thomas E

2013-02-01

Climate change can modify ecological interactions, but whether it can have cascading effects throughout ecological networks of multiple interacting species remains poorly studied. Climate-driven alterations in the intensity of plant-herbivore interactions may have particularly profound effects on the larger community because plants provide habitat for a wide diversity of organisms. Here we show that changes in vegetation over the last 21 years, due to climate effects on plant-herbivore interactions, have consequences for songbird nest site overlap and breeding success. Browsing-induced reductions in the availability of preferred nesting sites for two of three ground nesting songbirds led to increasing overlap in nest site characteristics among all three bird species with increasingly negative consequences for reproductive success over the long term. These results demonstrate that changes in the vegetation community from effects of climate change on plant-herbivore interactions can cause subtle shifts in ecological interactions that have critical demographic ramifications for other species in the larger community. © 2012 Blackwell Publishing Ltd.

Novel chemistry of invasive plants: exotic species have more unique metabolomic profiles than native congeners.

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Macel, Mirka; de Vos, Ric C H; Jansen, Jeroen J; van der Putten, Wim H; van Dam, Nicole M

2014-07-01

It is often assumed that exotic plants can become invasive when they possess novel secondary chemistry compared with native plants in the introduced range. Using untargeted metabolomic fingerprinting, we compared a broad range of metabolites of six successful exotic plant species and their native congeners of the family Asteraceae. Our results showed that plant chemistry is highly species-specific and diverse among both exotic and native species. Nonetheless, the exotic species had on average a higher total number of metabolites and more species-unique metabolites compared with their native congeners. Herbivory led to an overall increase in metabolites in all plant species. Generalist herbivore performance was lower on most of the exotic species compared with the native species. We conclude that high chemical diversity and large phytochemical uniqueness of the exotic species could be indicative of biological invasion potential.

Life styles of Colletotrichum species and implications for plant biosecurity

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Silva, Dilani D. De; Crous, Pedro W.; Ades, Peter Kevin; Hyde, Kevin D.; Taylor, Paul W. J.

Colletotrichum is a genus of major plant pathogens causing anthracnose diseases in many plant crops worldwide. The genus comprises a highly diverse group of pathogens that infect a wide range of plant hosts. The life styles of Colletotrichum species can be broadly categorised as necrotrophic,

Rare vascular plant species at risk : recovery by seeding?

NARCIS (Netherlands)

Pegtel, Dick M.

. Rare vascular plant species are endangered worldwide. Population losses are most commonly caused by human-related factors. Conservation management seeks to halt this adverse trend and if possible, to enhance long-lasting self-sustainable populations. In general, rare species are poorly recruited

The Role of Different Agricultural Plant Species in Air Pollution

Science.gov (United States)

Fiala, P.; Miller, D.; Shivers, S.; Pusede, S.; Roberts, D. A.

2017-12-01

The goal of this research project is to use remote sensing data to study the relationship between different plant species and the pollutants in the air. It is known that chemical reactions within plants serve as both sources and sinks for different types of Volatile Organic Compounds. However, the species-specific relationships have not been well studied. Through the better characterization of this relationship, certain aspects of air pollution may be more effectively managed. For this project, I used Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data and trace gas measurements from instruments on board the NASA DC-8 to assess the relationship between different plant species and the pollutants in the air. I used measurements primarily from the agricultural land surrounding Bakersfield, CA. I created a map of the crop species in this area using Multiple Endmember Spectral Mixture Analysis (MESMA) on the AVIRIS imagery, and matched this to trace gas measurements taken on the DC-8. I used a Hysplit matrix trajectory to account for the air transport over the vegetation and up to contact with the plane. Finally, I identified correlations between the plant types and the concentration of the pollutants. The results showed that there were significant relationships between specific species and pollutants, with lemons and grapes contributing to enhanced pollution, and tree nuts reducing pollution. Specifically, almonds produced significantly lower levels of O3 , NO, and NO2. Lemons and grapes had high O3 levels, and lemons had high levels of isoprene. In total, these data show that it may be possible to mitigate airborne pollution via selective planting; however, the overall environmental effects are much more complicated and must be analyzed further.

Alien plant species (ephemerophytes in Romensko-Poltavsky Geobotanical District, Ukraine

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Dvirna Tetyana S.

2017-09-01

Full Text Available This paper presents the results of research on ephemerophytes of the alien portion of the flora of the Romensko-Poltavsky Geobotanical District (north-eastern Ukraine. It is a detailed study of this group of plants, conducted for the first time in the Ukraine. The checklist of alien vascular plants contains 345 species, of which 27 species are ephemerophytes (or 8%: Adonis aestivalis, A. annua, Papaver albiflorum, Urtica cannabina, Gypsophila perfoliata, Atriplex micrantha, Chenopodium × preissmannii, Ch. × thellungii, Rumex longifolius, Sisymbrium polymorphum, Euphorbia humifusa, Malus sylvestris, Onobrychis viciifolia, Astrodaucus orientalis, Datura tatula, Solanum schultesii, Lindernia procumbens, Melampyrum cristatum, Helianthus annuus, Petasites spurius, Xanthium ripicola × Xanthium albinum, Echinochloa tzvelevii, Panicum capillare, Panicum capillare L. subsp. barvipulvinatum, Phalaris canariensis, Setaria ×ambigua, Sorghum halepense. The basis of this work is original data of the author obtained during field studies, and a critical study of the literature, archival, cartographic materials and herbarium collections, and the use of classical methods of botanical classification. Complex research of this group of plants was conducted and as a result of these investigations the following characteristics were established: a predominance of kenophytes of Mediterranean origin in this group, species of arid areas, cosmopolitan species with a diffuse type of space structure, therophytes, herbaceous monocarpic plants, mesotrophes, heliophytes and xeromesophytes, with an insignificant degree of impact on native plant communities and with a limited distribution within the study region. The combination of these results indicates that ephemerophytes comprise a temporary, unstable component of the flora of this region of the Ukraine. The paper provides maps of the distribution of these 27 species.

Rare and Endangered Geophyte Plant Species in Serpentine of Kosovo

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Naim Berisha

2014-12-01

Full Text Available Our study documents information on rarity, geographical distribution, taxonomy and conservation status of 11 geophyte species in serpentine soils of Kosovo, already included in the Red Book of Vascular Flora of Kosovo. Kosovo’s serpentine vegetation represents a diversity that yet has not been sufficiently explored. Large serpentine complexes are found in the northern Kosovo but also southern part of the country is rich in serpentines, therefore in endemics. Serpentine rocks and soils are characterized by low level of principal plant nutrients (N, P, K, Ca and exceptionally high levels of Mg and Fe. Serpentines play particular importance for flora of the country due to their richness in endemic plant species. The following 11 plant species have been studied: Aristolochia merxmuelleri, Colchicum hungaricum, Crocus flavus, Crocus kosaninii, Epimedium alpinum, Gentiana punctata, Gladiolus illyricus, Lilium albanicum, Paeonia peregrina, Tulipa gesneriana and Tulipa kosovarica. Five out of eleven studied geophytes fall within Critically Endangered IUCN based threat category and five out of eleven are local endemics. Aristolochia merxmuelleri and Tulipa kosovarica are steno-endemic plant species that are found exclusively in serpentine soils. Information in our database should prove to be valuable to efforts in ecology, floristics, biosystematics, conservation and land management.

Species composition, plant cover and diversity of recently reforested ...

African Journals Online (AJOL)

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2007-12-17

Dec 17, 2007 ... Deforestation, over-cultivation and rural growth have severely ... over-cultivation, plant populations changed, and biolo- ... Restoring community structure (e.g. species composi-tion ... plant diversity at all spatial scales are the criteria that should ..... taxonomic groups in recovering and restored forests.

The role of web sharing, species recognition and host-plant defence in interspecific competition between two herbivorous mite species.

Science.gov (United States)

Sato, Yukie; Alba, Juan M; Egas, Martijn; Sabelis, Maurice W

2016-11-01

When competing with indigenous species, invasive species face a problem, because they typically start with a few colonizers. Evidently, some species succeeded, begging an answer to the question how they invade. Here, we investigate how the invasive spider mite Tetranychus evansi interacts with the indigenous species T. urticae when sharing the solanaceous host plant tomato: do they choose to live together or to avoid each other's colonies? Both species spin protective, silken webs on the leaf surfaces, under which they live in groups of con- and possibly heterospecifics. In Spain, T. evansi invaded the non-crop field where native Tetranychus species including T. urticae dominated. Moreover, T. evansi outcompetes T. urticae when released together on a tomato plant. However, molecular plant studies suggest that T. urticae benefits from the local down-regulation of tomato plant defences by T. evansi, whereas T. evansi suffers from the induction of these defences by T. urticae. Therefore, we hypothesize that T. evansi avoids leaves infested with T. urticae whereas T. urticae prefers leaves infested by T. evansi. Using wild-type tomato and a mutant lacking jasmonate-mediated anti-herbivore defences, we tested the hypothesis and found that T. evansi avoided sharing webs with T. urticae in favour of a web with conspecifics, whereas T. urticae more frequently chose to share webs with T. evansi than with conspecifics. Also, T. evansi shows higher aggregation on a tomato plant than T. urticae, irrespective of whether the mites occur on the plant together or not.

[Relation between species distribution of plant community and soil factors under grazing in alpine meadow].

Science.gov (United States)

Niu, Yu Jie; Yang, Si Wei; Wang, Gui Zhen; Liu, Li; Du, Guo Zhen; Hua, Li Min

2017-12-01

The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different grazing intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the grazing caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low grazing intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of grazing intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against grazing intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration rate and large aggregate index were significantly changed with grazing intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under grazing. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest rate of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on grazed alpine meadow.

Assessment of heavy metal tolerance in native plant species from soils contaminated with electroplating effluent.

Science.gov (United States)

Sainger, Poonam Ahlawat; Dhankhar, Rajesh; Sainger, Manish; Kaushik, Anubha; Singh, Rana Pratap

2011-11-01

Heavy metals concentrations of (Cr, Zn, Fe, Cu and Ni) were determined in plants and soils contaminated with electroplating industrial effluent. The ranges of total soil Cr, Zn, Fe, Cu and Ni concentrations were found to be 1443-3240, 1376-3112, 683-2228, 263-374 and 234-335 mg kg⁻¹, respectively. Metal accumulation, along with hyperaccumulative characteristics of the screened plants was investigated. Present study highlighted that metal accumulation in different plants varied with species, tissues and metals. Only one plant (Amaranthus viridis) accumulated Fe concentrations over 1000 mg kg⁻¹. On the basis of TF, eight plant species for Zn and Fe, three plant species for Cu and two plant species for Ni, could be used in phytoextraction technology. Although BAF of all plant species was lesser than one, these species exhibited high metal adaptability and could be considered as potential hyperaccumulators. Phytoremediation potential of these plants can be used to remediate metal contaminated soils, though further investigation is still needed. Copyright © 2011 Elsevier Inc. All rights reserved.

Rapid plant evolution in the presence of an introduced species alters community composition.

Science.gov (United States)

Smith, David Solance; Lau, Matthew K; Jacobs, Ryan; Monroy, Jenna A; Shuster, Stephen M; Whitham, Thomas G

2015-10-01

Because introduced species may strongly interact with native species and thus affect their fitness, it is important to examine how these interactions can cascade to have ecological and evolutionary consequences for whole communities. Here, we examine the interactions among introduced Rocky Mountain elk, Cervus canadensis nelsoni, a common native plant, Solidago velutina, and the diverse plant-associated community of arthropods. While introduced species are recognized as one of the biggest threats to native ecosystems, relatively few studies have investigated an evolutionary mechanism by which introduced species alter native communities. Here, we use a common garden design that addresses and supports two hypotheses. First, native S. velutina has rapidly evolved in the presence of introduced elk. We found that plants originating from sites with introduced elk flowered nearly 3 weeks before plants originating from sites without elk. Second, evolution of S. velutina results in a change to the plant-associated arthropod community. We found that plants originating from sites with introduced elk supported an arthropod community that had ~35 % fewer total individuals and a different species composition. Our results show that the impacts of introduced species can have both ecological and evolutionary consequences for strongly interacting species that subsequently cascade to affect a much larger community. Such evolutionary consequences are likely to be long-term and difficult to remediate.

Cyclic public goods games: Compensated coexistence among mutual cheaters stabilized by optimized penalty taxation

Science.gov (United States)

Griffin, Christopher; Belmonte, Andrew

2017-05-01

We study the problem of stabilized coexistence in a three-species public goods game in which each species simultaneously contributes to one public good while freeloading off another public good ("cheating"). The proportional population growth is governed by an appropriately modified replicator equation, depending on the returns from the public goods and the cost. We show that the replicator dynamic has at most one interior unstable fixed point and that the population becomes dominated by a single species. We then show that by applying an externally imposed penalty, or "tax" on success can stabilize the interior fixed point, allowing for the symbiotic coexistence of all species. We show that the interior fixed point is the point of globally minimal total population growth in both the taxed and untaxed cases. We then formulate an optimal taxation problem and show that it admits a quasilinearization, resulting in novel necessary conditions for the optimal control. In particular, the optimal control problem governing the tax rate must solve a certain second-order ordinary differential equation.

Pollination Biology and Spatio-Temporal Structuring of Some Major Acacia Species (Leguminosae) of the Arabian Peninsula

International Nuclear Information System (INIS)

Adgaba, N.; Alghamidi, A.; Tadesse, Y.; Getachew, A.; Ansari, M. J.

2016-01-01

Acacias are the dominant woody plant species distributed over the vast tracts of land throughout the Arabian Peninsula. However, information on spatio-temporal structuring and pollination biology of the species is not precisely available. To determine whether any variations exist among the Acacia species in their temporal distribution, their flowering period was determined through monitoring the commencing, peaking and ending of flowering of each species. Moreover, if any variations exist in release of floral rewards among the different co-existing and co-flowering species as mechanisms of partitioning of pollinators, to minimize competition for pollination, the progress of their anthesis over time was recorded by scoring polyads to anthers ratio at different hours of a day. In addition, the amount and dynamics of nectar sugar per inflorescence (N =225/species) was determined following flower nectar sugar washing technique. Types and frequencies of flower visitors and their preferences were determined by recording the visitors 6 times a day. The current study revealed that the Acacia species of the Arabian Peninsula are spatio-temporally structured: some species co-exist yet have different flowering seasons, whereas others co-exist, flowering concurrently yet exhibit a shift in their time of peak flowering and in the time at which the peak pollen is released during the day. This study demonstrates that all Acacia species examined secrete a considerable amount of nectar (2.24+-1.72 -10.02+-4.0mg/inflorescence) which serves as a floral reward for pollinators. Insects of the Order Hymenoptera are the most prevalent visitors to Acacia species in the region. The variations in spatio-temporal structuring of the Acaciaspecies could be due to their adaptation of reducing competition for pollinators and minimizing hetero-specific pollen transfer. (author)

Environmental variability facilitates coexistence within an alcid community at sea

Science.gov (United States)

Haney, J. Christopher; Schauer, Amy E.S.

1994-01-01

We examined coexistence at sea among 7 taxa of diving, wing-propelled seabirds (Alcidae) in the genera Aethia, Uria, Cepphus, and Fratercula. Species abundances were measured simultaneously with a suite of environmental factors in the northern Bering Sea, Alaska, USA; data from 260 adjacent and non-adjacent sites occupied by alcids foraging offshore near breeding colonies were then subjected to principal component analysis (PCA). We used PCA to group redundant environmental descriptors, to identify orthogonal axes for constructing a multi-dimensional niche, and to differentiate species associations within niche dimensions from species associations among niche dimensions. Decomposition of the correlation matrix for 22 environmental and 7 taxonomic variables with PCA gave 14 components (10 environmental and 4 species interactions) that retained 90% of the original available variance. Alcid abundances (all species) were most strongly correlated with axes representing tidal stage, a time-area interaction (due to sampling layout), water masses, and a temporal or intra-seasonal trend partially associated with weather changes. Axes representing tidal stage, 2 gradients in macro-habitat (Anadyr and Bering Shelf Water masses), the micro-habitat of the sea surface, and an air-sea interaction were most important for detecting differences among species within niche dimensions. Contrary to assumptions of competition, none of 4 compound variables describing primarily species-interactions gave strong evidence for negative associations between alcid taxa sharing similar body sizes and feeding requirements. This exploratory analysis supports the view that alcids may segregate along environmental gradients at sea. But in this community, segregation was unrelated to foraging distance from colonies, in part because foraging 'substrate' was highly variable in structure, location, and area1 extent. We contend that coexistence within this seabird group is facilitated via expanded niche

Invasive clonal plant species have a greater root-foraging plasticity than non-invasive ones.

Science.gov (United States)

Keser, Lidewij H; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

2014-03-01

Clonality is frequently positively correlated with plant invasiveness, but which aspects of clonality make some clonal species more invasive than others is not known. Due to their spreading growth form, clonal plants are likely to experience spatial heterogeneity in nutrient availability. Plasticity in allocation of biomass to clonal growth organs and roots may allow these plants to forage for high-nutrient patches. We investigated whether this foraging response is stronger in species that have become invasive than in species that have not. We used six confamilial pairs of native European clonal plant species differing in invasion success in the USA. We grew all species in large pots under homogeneous or heterogeneous nutrient conditions in a greenhouse, and compared their nutrient-foraging response and performance. Neither invasive nor non-invasive species showed significant foraging responses to heterogeneity in clonal growth organ biomass or in aboveground biomass of clonal offspring. Invasive species had, however, a greater positive foraging response in terms of root and belowground biomass than non-invasive species. Invasive species also produced more total biomass. Our results suggest that the ability for strong root foraging is among the characteristics promoting invasiveness in clonal plants.

Evolutionary history determines how plant productivity responds to phylogenetic diversity and species richness

Directory of Open Access Journals (Sweden)

Mark A. Genung

2014-03-01

Full Text Available The relationship between biodiversity and ecosystem function has received a great deal of attention in ecological research and recent results, from re-analyses, suggest that ecosystem function improves with increases in phylogenetic diversity. However, many of these results have been generalized across a range of different species and clades, and plants with different evolutionary histories could display different relationships between biodiversity and ecosystem function. To experimentally test this hypothesis, we manipulated species richness and phylogenetic diversity using 26 species from two subgenera of the genus Eucalyptus (subgenus Eucalyptus and subgenus Symphyomyrtus. We found that plant biomass (a measurement of ecosystem function sometimes, but not always, responded to increases in species richness and phylogenetic diversity. Specifically, Symphyomyrtus plants showed a positive response while no comparable effect was observed for Eucalyptus plants, showing that responses to biodiversity can vary across different phylogenetic groups. Our results show that the impacts of evolutionary history may complicate the relationship between the diversity of plant communities and plant biomass.

Plant trait-species abundance relationships vary with environmental properties in subtropical forests in eastern china.

Directory of Open Access Journals (Sweden)

En-Rong Yan

Full Text Available Understanding how plant trait-species abundance relationships change with a range of single and multivariate environmental properties is crucial for explaining species abundance and rarity. In this study, the abundance of 94 woody plant species was examined and related to 15 plant leaf and wood traits at both local and landscape scales involving 31 plots in subtropical forests in eastern China. Further, plant trait-species abundance relationships were related to a range of single and multivariate (PCA axes environmental properties such as air humidity, soil moisture content, soil temperature, soil pH, and soil organic matter, nitrogen (N and phosphorus (P contents. At the landscape scale, plant maximum height, and twig and stem wood densities were positively correlated, whereas mean leaf area (MLA, leaf N concentration (LN, and total leaf area per twig size (TLA were negatively correlated with species abundance. At the plot scale, plant maximum height, leaf and twig dry matter contents, twig and stem wood densities were positively correlated, but MLA, specific leaf area, LN, leaf P concentration and TLA were negatively correlated with species abundance. Plant trait-species abundance relationships shifted over the range of seven single environmental properties and along multivariate environmental axes in a similar way. In conclusion, strong relationships between plant traits and species abundance existed among and within communities. Significant shifts in plant trait-species abundance relationships in a range of environmental properties suggest strong environmental filtering processes that influence species abundance and rarity in the studied subtropical forests.

Changes in plant species richness induce functional shifts in soil nematode communities in experimental grassland.

Directory of Open Access Journals (Sweden)

Nico Eisenhauer

Full Text Available Changes in plant diversity may induce distinct changes in soil food web structure and accompanying soil feedbacks to plants. However, knowledge of the long-term consequences of plant community simplification for soil animal food webs and functioning is scarce. Nematodes, the most abundant and diverse soil Metazoa, represent the complexity of soil food webs as they comprise all major trophic groups and allow calculation of a number of functional indices.We studied the functional composition of nematode communities three and five years after establishment of a grassland plant diversity experiment (Jena Experiment. In response to plant community simplification common nematode species disappeared and pronounced functional shifts in community structure occurred. The relevance of the fungal energy channel was higher in spring 2007 than in autumn 2005, particularly in species-rich plant assemblages. This resulted in a significant positive relationship between plant species richness and the ratio of fungal-to-bacterial feeders. Moreover, the density of predators increased significantly with plant diversity after five years, pointing to increased soil food web complexity in species-rich plant assemblages. Remarkably, in complex plant communities the nematode community shifted in favour of microbivores and predators, thereby reducing the relative abundance of plant feeders after five years.The results suggest that species-poor plant assemblages may suffer from nematode communities detrimental to plants, whereas species-rich plant assemblages support a higher proportion of microbivorous nematodes stimulating nutrient cycling and hence plant performance; i.e. effects of nematodes on plants may switch from negative to positive. Overall, food web complexity is likely to decrease in response to plant community simplification and results of this study suggest that this results mainly from the loss of common species which likely alter plant-nematode interactions.

Comparative analysis of diosgenin in Dioscorea species and related medicinal plants by UPLC-DAD-MS.

Science.gov (United States)

Yi, Tao; Fan, Lan-Lan; Chen, Hong-Li; Zhu, Guo-Yuan; Suen, Hau-Man; Tang, Yi-Na; Zhu, Lin; Chu, Chu; Zhao, Zhong-Zhen; Chen, Hu-Biao

2014-08-09

Dioscorea is a genus of flowering plants, and some Dioscorea species are known and used as a source for the steroidal sapogenin diosgenin. To screen potential resource from Dioscorea species and related medicinal plants for diosgenin extraction, a rapid method to compare the contents of diosgenin in various plants is crucial. An ultra-performance liquid chromatography (UPLC) coupled with diode array detection (DAD) and electrospray ionization mass spectrometry (ESI-MS) method was developed for identification and determination of diosgenin in various plants. A comprehensive validation of the developed method was conducted. Twenty-four batches of plant samples from four Dioscorea species, one Smilax species and two Heterosmilax species were analyzed by using the developed method.The present method presented good sensitivity, precision and accuracy. Diosgenin was found in three Dioscorea species and one Heterosmilax species, namely D. zingiberensis, D. septemloba, D. collettii and H. yunnanensis. The method is suitable for the screening of diosgenin resources from plants. D. zingiberensis is an important resource for diosgenin harvesting.

ecotaxonomic baseline evaluation of the plant species in a ...

African Journals Online (AJOL)

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plant species of medicinal and other economic values. The investigation was ... A total of 41 and 24 representative ... INTRODUCTION. Baseline .... at 100m interval, involving a total of 15 sampling locations .... explained by factors such as climate, productivity and ... encouraging the: Maintenance of traditional tree species.

Plant species richness and ecosystem multifunctionality in global drylands

Science.gov (United States)

Maestre, Fernando T.; Quero, Jose L.; Gotelli, Nicholas J.; Escudero, Adrian; Ochoa, Victoria; Delgado-Baquerizo, Manuel; Garcia-Gomez, Miguel; Bowker, Matthew A.; Soliveres, Santiago; Escolar, Cristina; Garcia-Palacios, Pablo; Berdugo, Miguel; Valencia, Enrique; Gozalo, Beatriz; Gallardo, Antonio; Aguilera, Lorgio; Arredondo, Tulio; Blones, Julio; Boeken, Bertrand; Bran, Donaldo; Conceicao, Abel A.; Cabrera, Omar; Chaieb, Mohamed; Derak, Mchich; Eldridge, David J.; Espinosa, Carlos I.; Florentino, Adriana; Gaitan, Juan; Gatica, M. Gabriel; Ghiloufi, Wahida; Gomez-Gonzalez, Susana; Gutie, Julio R.; Hernandez, Rosa M.; Huang, Xuewen; Huber-Sannwald, Elisabeth; Jankju, Mohammad; Miriti, Maria; Monerris, Jorge; Mau, Rebecca L.; Morici, Ernesto; Naseri, Kamal; Ospina, Abelardo; Polo, Vicente; Prina, Anibal; Pucheta, Eduardo; Ramirez-Collantes, David A.; Romao, Roberto; Tighe, Matthew; Torres-Diaz, Cristian; Val, James; Veiga, Jose P.; Wang, Deli; Zaady, Eli

2012-01-01

Experiments suggest that biodiversity enhances the ability of ecosystems to maintain multiple functions, such as carbon storage, productivity, and the buildup of nutrient pools (multifunctionality). However, the relationship between biodiversity and multifunctionality has never been assessed globally in natural ecosystems. We report here on a global empirical study relating plant species richness and abiotic factors to multifunctionality in drylands, which collectively cover 41% of Earth's land surface and support over 38% of the human population. Multifunctionality was positively and significantly related to species richness. The best-fitting models accounted for over 55% of the variation in multifunctionality and always included species richness as a predictor variable. Our results suggest that the preservation of plant biodiversity is crucial to buffer negative effects of climate change and desertification in drylands.

Phytoremediation of soil co-contaminated with heavy metals and TNT using four plant species.

Science.gov (United States)

Lee, Insook; Baek, Kyunghwa; Kim, Hyunhee; Kim, Sunghyun; Kim, Jaisoo; Kwon, Youngseok; Chang, Yoontoung; Bae, Bumhan

2007-11-01

We investigated the germination, growth rates and uptake of contaminants of four plant species, barnyard grass (Echinochloa crusgalli), sunflower (Helianthus annuus), Indian mallow (Abutilon avicennae) and Indian jointvetch (Aeschynomene indica), grown in soil contaminated with cadmium (Cd), lead (Pb) and 2,4,6-trinitrotoluene (TNT). These contaminants are typically found at shooting ranges. Experiments were carried out over 180 days using both single plant cultures and cultures containing an equal mix of the 4 plant species. Germination rates differed among the species in single culture (92% for H. annuus, 84% for E. crusgalli, 48% for A. avicennae and 38% Ae. indica). In the 4-plant mix culture, phytoremediation for the removal of heavy metals and TNT from contaminated soils should use a single plant species rather than a mixture of several plants.

Crosstalk between sugarcane and a plant-growth promoting Burkholderia species

Science.gov (United States)

Paungfoo-Lonhienne, Chanyarat; Lonhienne, Thierry G. A.; Yeoh, Yun Kit; Donose, Bogdan C.; Webb, Richard I.; Parsons, Jeremy; Liao, Webber; Sagulenko, Evgeny; Lakshmanan, Prakash; Hugenholtz, Philip; Schmidt, Susanne; Ragan, Mark A.

2016-01-01

Bacterial species in the plant-beneficial-environmental clade of Burkholderia represent a substantial component of rhizosphere microbes in many plant species. To better understand the molecular mechanisms of the interaction, we combined functional studies with high-resolution dual transcriptome analysis of sugarcane and root-associated diazotrophic Burkholderia strain Q208. We show that Burkholderia Q208 forms a biofilm at the root surface and suppresses the virulence factors that typically trigger immune response in plants. Up-regulation of bd-type cytochromes in Burkholderia Q208 suggests an increased energy production and creates the microaerobic conditions suitable for BNF. In this environment, a series of metabolic pathways are activated in Burkholderia Q208 implicated in oxalotrophy, microaerobic respiration, and formation of PHB granules, enabling energy production under microaerobic conditions. In the plant, genes involved in hypoxia survival are up-regulated and through increased ethylene production, larger aerenchyma is produced in roots which in turn facilitates diffusion of oxygen within the cortex. The detected changes in gene expression, physiology and morphology in the partnership are evidence of a sophisticated interplay between sugarcane and a plant-growth promoting Burkholderia species that advance our understanding of the mutually beneficial processes occurring in the rhizosphere. PMID:27869215

Plant DNA barcodes can accurately estimate species richness in poorly known floras.

Science.gov (United States)

Costion, Craig; Ford, Andrew; Cross, Hugh; Crayn, Darren; Harrington, Mark; Lowe, Andrew

2011-01-01

Widespread uptake of DNA barcoding technology for vascular plants has been slow due to the relatively poor resolution of species discrimination (∼70%) and low sequencing and amplification success of one of the two official barcoding loci, matK. Studies to date have mostly focused on finding a solution to these intrinsic limitations of the markers, rather than posing questions that can maximize the utility of DNA barcodes for plants with the current technology. Here we test the ability of plant DNA barcodes using the two official barcoding loci, rbcLa and matK, plus an alternative barcoding locus, trnH-psbA, to estimate the species diversity of trees in a tropical rainforest plot. Species discrimination accuracy was similar to findings from previous studies but species richness estimation accuracy proved higher, up to 89%. All combinations which included the trnH-psbA locus performed better at both species discrimination and richness estimation than matK, which showed little enhanced species discriminatory power when concatenated with rbcLa. The utility of the trnH-psbA locus is limited however, by the occurrence of intraspecific variation observed in some angiosperm families to occur as an inversion that obscures the monophyly of species. We demonstrate for the first time, using a case study, the potential of plant DNA barcodes for the rapid estimation of species richness in taxonomically poorly known areas or cryptic populations revealing a powerful new tool for rapid biodiversity assessment. The combination of the rbcLa and trnH-psbA loci performed better for this purpose than any two-locus combination that included matK. We show that although DNA barcodes fail to discriminate all species of plants, new perspectives and methods on biodiversity value and quantification may overshadow some of these shortcomings by applying barcode data in new ways.

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.

Distribution patterns of rare earth elements in various plant species

International Nuclear Information System (INIS)

Wyttenbach, A.; Tobler, L.; Furrer, V.

1997-01-01

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

Cultural significance of medicinal plant families and species among Quechua farmers in Apillapampa, Bolivia.

Science.gov (United States)

Thomas, Evert; Vandebroek, Ina; Sanca, Sabino; Van Damme, Patrick

2009-02-25

Medicinal plant use was investigated in Apillapampa, a community of subsistence farmers located in the semi-arid Bolivian Andes. The main objectives were to identify the culturally most significant medicinal plant families and species in Apillapampa. A total of 341 medicinal plant species was inventoried during guided fieldtrips and transect sampling. Data on medicinal uses were obtained from fifteen local Quechua participants, eight of them being traditional healers. Contingency table and binomial analyses of medicinal plants used versus the total number of inventoried species per family showed that Solanaceae is significantly overused in traditional medicine, whereas Poaceae is underused. Also plants with a shrubby habitat are significantly overrepresented in the medicinal plant inventory, which most likely relates to their year-round availability to people as compared to most annual plants that disappear in the dry season. Our ranking of medicinal species according to cultural importance is based upon the Quality Use Agreement Value (QUAV) index we developed. This index takes into account (1) the average number of medicinal uses reported for each plant species by participants; (2) the perceived quality of those medicinal uses; and (3) participant consensus. According to the results, the QUAV index provides an easily derived and valid appraisal of a medicinal plant's cultural significance.

Interspecific competition of early successional plant species in ex-arable fields as influenced by plant-soil feedback

NARCIS (Netherlands)

Jing, Jingying; Bezemer, T. Martijn; Van der Putten, Wim H.

2015-01-01

Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from

Mercury uptake and accumulation by four species of aquatic plants

International Nuclear Information System (INIS)

Skinner, Kathleen; Wright, Nicole; Porter-Goff, Emily

2007-01-01

The effectiveness of four aquatic plants including water hyacinth (Eichornia crassipes), water lettuce (Pistia stratiotes), zebra rush (Scirpus tabernaemontani) and taro (Colocasia esculenta) were evaluated for their capabilities in removing mercury from water. The plants were exposed to concentrations of 0 mg/L, 0.5 mg/L or 2 mg/L of mercury for 30 days. Assays were conducted using both Microtox[reg] (water) and cold vapor Atomic Absorption Spectroscopy (AAS) (roots and water). The Microtox[reg] results indicated that the mercury induced acute toxicity had been removed from the water. AAS confirmed an increase of mercury within the plant root tissue and a corresponding decrease of mercury in the water. All species of plants appeared to reduce mercury concentrations in the water via root uptake and accumulation. Water lettuce and water hyacinth appeared to be the most effective, followed by taro and zebra rush, respectively. - Four species of aquatic plants reduced mercury in water

Mercury uptake and accumulation by four species of aquatic plants

Energy Technology Data Exchange (ETDEWEB)

Skinner, Kathleen [Department of Biology, Russell Sage College, 45 Ferry Street, Troy, NY 12180 (United States)]. E-mail: skinnk@sage.edu; Wright, Nicole [NEIWPCC-NYSDEC, 625 Broadway, 4th Floor, Albany, NY 12233-3502 (United States)]. E-mail: ndwright@gw.dec.state.ny.us; Porter-Goff, Emily [Department of Biology, Russell Sage College, 45 Ferry Street, Troy, NY 12180 (United States)

2007-01-15

The effectiveness of four aquatic plants including water hyacinth (Eichornia crassipes), water lettuce (Pistia stratiotes), zebra rush (Scirpus tabernaemontani) and taro (Colocasia esculenta) were evaluated for their capabilities in removing mercury from water. The plants were exposed to concentrations of 0 mg/L, 0.5 mg/L or 2 mg/L of mercury for 30 days. Assays were conducted using both Microtox[reg] (water) and cold vapor Atomic Absorption Spectroscopy (AAS) (roots and water). The Microtox[reg] results indicated that the mercury induced acute toxicity had been removed from the water. AAS confirmed an increase of mercury within the plant root tissue and a corresponding decrease of mercury in the water. All species of plants appeared to reduce mercury concentrations in the water via root uptake and accumulation. Water lettuce and water hyacinth appeared to be the most effective, followed by taro and zebra rush, respectively. - Four species of aquatic plants reduced mercury in water.

Growth responses of maritime sand dune plant species to arbuscular mycorrhizal fungi

Directory of Open Access Journals (Sweden)

Mariusz Tadych

2014-08-01

Full Text Available In a pot experiment conducted in a greenhouse, the response of 6 plant species dominating in the succession of vegetation of a deflation hollow of the Łeba Bar to inoculation with arbuscular mycorrhizal fungi (AMF was investigated. The inoculum was a mixture of soil, roots and spores of 5 species of AMF with the dominant species Glomus aggregatum. Except for Corynephorus canescens and Festuca rubra subsp. arenaria, both the growth and the dry matter of above-ground parts of plants of Agrostis stolonifera, Ammophila arenaria, Corynephorus canescens, Juncus articulatus and J. balticus inoculated with AMF were higher than those growing in soils lacking infection propagules of these fungi. Inoculation with AMF decreased the dry matter of root: shoot ratios in 5 plant species. This property was not determined in Festuca rubra subsp. arenaria due to the death of all control plants. The level of mycorrhizal infection was low and did not correlate with the growth responses found. The high growth reaction of Juncus spp. to AMF found in this study suggests that the opinion of non-mycotrophy or low dependence of plants of Juncaceae on AMF was based on results of investigations of plants growing in wet sites known to inhibit the formation of mycorrhizae.

Stability of modularity and structural keystone species in temporal cumulative plant- flower-visitor networks

DEFF Research Database (Denmark)

Dupont, Yoko; Olesen, Jens Mogens

2012-01-01

Modularity is a structural property of ecological networks, which has received much interest, but has been poorly explored. Modules are distinct subsets of species interacting strongly with each other, but sparsely with species outside the subset. Using a series of temporal cumulative networks, we...... all flowering plants and flower-visiting insect species throughout the flowering season at three dry heathland sites in Denmark. For each site, we constructed cumulative networks every 0.5 months, resulting in series of 10–12 networks per site. Numbers of interactions, and plant and insect species...... around one or two hubs. These hub species encompassed a small number of plant species, many of which acted as hubs at several study sites and throughout most of their flowering season. Thus, these plants become of key importance in maintaining the structure of their pollination network. We conclude...

Wild Plant Species with Extremely Small Populations Require Conservation and Reintroduction in China

Science.gov (United States)

Hai Ren; Qianmei Zhang; Hongfang Lu; Hongxiao Liu; Qinfeng Guo; Jun Wang; Shuguang Jian; Hai’ou Bao

2012-01-01

China is exceptionally rich in biodiversity, with more than 30000 vascular plant species that include many endemic genera, species of ancient origin, and cultivated plants (Yang et al. 2005). Because of rapid economic development, population growth, pollution, and continuing resource exploitation, China’s plant diversity faces severe threats. According to the Chinese...

45 CFR 670.25 - Designation of specially protected species of native mammals, birds, and plants.

Science.gov (United States)

2010-10-01

... native mammals, birds, and plants. 670.25 Section 670.25 Public Welfare Regulations Relating to Public... Protected Species of Mammals, Birds, and Plants § 670.25 Designation of specially protected species of native mammals, birds, and plants. The following species has been designated as Specially Protected...

Monitoring the effects of atmospheric ethylene near polyethylene manufacturing plants with two sensitive plant species

NARCIS (Netherlands)

Tonneijck, A.E.G.; Berge, ten W.F.; Jansen, B.P.

2003-01-01

Data of a multi-year (1977-1983) biomonitoring programme with marigold and petunia around polyethylene manufacturing plants was analysed to assess plant responses to atmospheric ethylene and to determine the area at risk for the phytotoxic effects of this pollutant. In both species, flower formation

Resource partitioning by evergreen and deciduous species in a tropical dry forest.

Science.gov (United States)

Álvarez-Yépiz, Juan C; Búrquez, Alberto; Martínez-Yrízar, Angelina; Teece, Mark; Yépez, Enrico A; Dovciak, Martin

2017-02-01

Niche differentiation can lead to coexistence of plant species by partitioning limiting resources. Light partitioning promotes niche differentiation in tropical humid forests, but it is unclear how niche partitioning occurs in tropical dry forests where both light and soil resources can be limiting. We studied the adult niche of four dominant evergreen (cycad, palm) and drought-deciduous (legume, oak) species co-occurring along environmental gradients. We analyzed light intensity and soil fertility effects on key functional traits related to plant carbon and water economy, how these traits determine species' functional strategies, and how these strategies relate to relative species abundance and spatial patterns. Light intensity was negatively associated with a key trait linked to plant water economy (leaf δ 13 C, a proxy for long-term water-use efficiency-WUE), while soil fertility was negatively associated with a key trait for plant carbon economy (LNC, leaf nitrogen content). Evergreens were highly sclerophyllous and displayed an efficient water economy but poor carbon economy, in agreement with a conservative resource-use strategy (i.e., high WUE but low LNC, photosynthetic rates and stature). Conversely, deciduous species, with an efficient carbon economy but poor water economy, exhibited an exploitative resource-use strategy (i.e., high LNC, photosynthetic rates and stature, but low WUE). Evergreen and deciduous species segregated spatially, particularly at fine-scales, as expected for species with different resource-use strategies. The efficient water economy of evergreens was related to their higher relative abundance, suggesting a functional advantage against drought-deciduous species in water-limited environments within seasonally dry tropical forests.

Links between plant litter chemistry, species diversity, and below-ground ecosystem function

OpenAIRE

Meier, Courtney L.; Bowman, William D.

2008-01-01

Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics...

Recognition of root exudates by seeds of broomrape (Orobanche and Phelipanche) species

Science.gov (United States)

Fernández-Aparicio, M.; Flores, F.; Rubiales, D.

2009-01-01

Background and Aims The long co-existence of broomrapes and their hosts within the same environment has culminated in a strong adaptation and effective parasitism. As a first step of specialization in the parasitic process, seed receptors of parasitic plant species vary in their ability to recognize compounds released by their hosts. This work aims to investigate potential patterns for the reception requirements needed to activate germination within Orobanche and Phelipanche species. Methods Induction of the germination of seeds of nine Orobanche and Pheliphanche species by root exudates of 41 plant species was studied and subjected to biplot multivariate analysis. Key Results A high level of specialization in root exudate recognition was found in Orobanche densiflora, O. gracilis and O. hederae, which germinated almost exclusively in contact with root exudates from the plants they infect in nature. At the opposite extreme, Phelipanche aegyptiaca, P. ramosa and O. minor were highly generalist, germinating when in contact with the root exudates of most plant species. Orobanche crenata, O. cumana and O. foetida showed intermediate behaviour. Conclusions A universal germination stimulant for all broomrape species has not being identified to date. The synthetic stimulant GR24 is active against most of the weedy broomrape species, but fails with the non-weedy species tested in this study and with the very recent weedy species O. foetida. In addition, germination behaviour of broomrape species depends on the crop plant tested. Weedy broomrapes with a broad host spectrum respond better to the different exudates released by a wide range of crops and wild species than do non-weedy broomrapes, which have a narrow host spectrum and are more restricted to their host range. Root exudates of many plant species were active in stimulating germination of seeds of Orobanche and Phelipanche species for which they are not described as hosts, representing interesting examples of

Climate and soil attributes determine plant species turnover in global drylands.

Science.gov (United States)

Ulrich, Werner; Soliveres, Santiago; Maestre, Fernando T; Gotelli, Nicholas J; Quero, José L; Delgado-Baquerizo, Manuel; Bowker, Matthew A; Eldridge, David J; Ochoa, Victoria; Gozalo, Beatriz; Valencia, Enrique; Berdugo, Miguel; Escolar, Cristina; García-Gómez, Miguel; Escudero, Adrián; Prina, Aníbal; Alfonso, Graciela; Arredondo, Tulio; Bran, Donaldo; Cabrera, Omar; Cea, Alex; Chaieb, Mohamed; Contreras, Jorge; Derak, Mchich; Espinosa, Carlos I; Florentino, Adriana; Gaitán, Juan; Muro, Victoria García; Ghiloufi, Wahida; Gómez-González, Susana; Gutiérrez, Julio R; Hernández, Rosa M; Huber-Sannwald, Elisabeth; Jankju, Mohammad; Mau, Rebecca L; Hughes, Frederic Mendes; Miriti, Maria; Monerris, Jorge; Muchane, Muchai; Naseri, Kamal; Pucheta, Eduardo; Ramírez-Collantes, David A; Raveh, Eran; Romão, Roberto L; Torres-Díaz, Cristian; Val, James; Veiga, José Pablo; Wang, Deli; Yuan, Xia; Zaady, Eli

2014-12-01

Geographic, climatic, and soil factors are major drivers of plant beta diversity, but their importance for dryland plant communities is poorly known. This study aims to: i) characterize patterns of beta diversity in global drylands, ii) detect common environmental drivers of beta diversity, and iii) test for thresholds in environmental conditions driving potential shifts in plant species composition. 224 sites in diverse dryland plant communities from 22 geographical regions in six continents. Beta diversity was quantified with four complementary measures: the percentage of singletons (species occurring at only one site), Whittake's beta diversity (β(W)), a directional beta diversity metric based on the correlation in species occurrences among spatially contiguous sites (β(R 2 )), and a multivariate abundance-based metric (β(MV)). We used linear modelling to quantify the relationships between these metrics of beta diversity and geographic, climatic, and soil variables. Soil fertility and variability in temperature and rainfall, and to a lesser extent latitude, were the most important environmental predictors of beta diversity. Metrics related to species identity (percentage of singletons and β(W)) were most sensitive to soil fertility, whereas those metrics related to environmental gradients and abundance ((β(R 2 )) and β(MV)) were more associated with climate variability. Interactions among soil variables, climatic factors, and plant cover were not important determinants of beta diversity. Sites receiving less than 178 mm of annual rainfall differed sharply in species composition from more mesic sites (> 200 mm). Soil fertility and variability in temperature and rainfall are the most important environmental predictors of variation in plant beta diversity in global drylands. Our results suggest that those sites annually receiving ~ 178 mm of rainfall will be especially sensitive to future climate changes. These findings may help to define appropriate

Climate and soil attributes determine plant species turnover in global drylands

Science.gov (United States)

Maestre, Fernando T.; Gotelli, Nicholas J.; Quero, José L.; Delgado-Baquerizo, Manuel; Bowker, Matthew A.; Eldridge, David J.; Ochoa, Victoria; Gozalo, Beatriz; Valencia, Enrique; Berdugo, Miguel; Escolar, Cristina; García-Gómez, Miguel; Escudero, Adrián; Prina, Aníbal; Alfonso, Graciela; Arredondo, Tulio; Bran, Donaldo; Cabrera, Omar; Cea, Alex; Chaieb, Mohamed; Contreras, Jorge; Derak, Mchich; Espinosa, Carlos I.; Florentino, Adriana; Gaitán, Juan; Muro, Victoria García; Ghiloufi, Wahida; Gómez-González, Susana; Gutiérrez, Julio R.; Hernández, Rosa M.; Huber-Sannwald, Elisabeth; Jankju, Mohammad; Mau, Rebecca L.; Hughes, Frederic Mendes; Miriti, Maria; Monerris, Jorge; Muchane, Muchai; Naseri, Kamal; Pucheta, Eduardo; Ramírez-Collantes, David A.; Raveh, Eran; Romão, Roberto L.; Torres-Díaz, Cristian; Val, James; Veiga, José Pablo; Wang, Deli; Yuan, Xia; Zaady, Eli

2015-01-01

Aim Geographic, climatic, and soil factors are major drivers of plant beta diversity, but their importance for dryland plant communities is poorly known. This study aims to: i) characterize patterns of beta diversity in global drylands, ii) detect common environmental drivers of beta diversity, and iii) test for thresholds in environmental conditions driving potential shifts in plant species composition. Location 224 sites in diverse dryland plant communities from 22 geographical regions in six continents. Methods Beta diversity was quantified with four complementary measures: the percentage of singletons (species occurring at only one site), Whittake’s beta diversity (β(W)), a directional beta diversity metric based on the correlation in species occurrences among spatially contiguous sites (β(R2)), and a multivariate abundance-based metric (β(MV)). We used linear modelling to quantify the relationships between these metrics of beta diversity and geographic, climatic, and soil variables. Results Soil fertility and variability in temperature and rainfall, and to a lesser extent latitude, were the most important environmental predictors of beta diversity. Metrics related to species identity (percentage of singletons and β(W)) were most sensitive to soil fertility, whereas those metrics related to environmental gradients and abundance ((β(R2)) and β(MV)) were more associated with climate variability. Interactions among soil variables, climatic factors, and plant cover were not important determinants of beta diversity. Sites receiving less than 178 mm of annual rainfall differed sharply in species composition from more mesic sites (> 200 mm). Main conclusions Soil fertility and variability in temperature and rainfall are the most important environmental predictors of variation in plant beta diversity in global drylands. Our results suggest that those sites annually receiving ~ 178 mm of rainfall will be especially sensitive to future climate changes. These

CE of phytosiderophores and related metal species in plants.

Science.gov (United States)

Xuan, Yue; Scheuermann, Enrico B; Meda, Anderson R; Jacob, Peter; von Wirén, Nicolaus; Weber, Günther

2007-10-01

Phytosiderophores (PS) and the closely related substance nicotianamine (NA) are key substances in metal uptake into graminaceous plants. Here, the CE separation of these substances and related metal species is demonstrated. In particular, the three PS 2'-deoxymugineic acid (DMA), mugineic acid (MA), and 3-epi-hydroxymugineic acid (epi-HMA), and NA, are separated using MES/Tris buffer at pH 7.3. Moreover, three Fe(III) species of the different PS are separated without any stability problems, which are often present in chromatographic analyses. Also divalent metal species of Cu, Ni, and Zn with the ligands DMA and NA are separated with the same method. By using a special, zwitterionic CE capillary, even the separation of two isomeric Fe(III) chelates with the ligand ethylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid (EDDHA) is possible (i.e., meso-Fe(III)-EDDHA and rac-Fe(III)-EDDHA), and for fast separations of NA and respective divalent and trivalent metal species, a polymer CE microchip with suppressed EOF is described. The proposed CE method is applicable to real plant samples, and enables to detect changes of metal species (Cu-DMA, Ni-NA), which are directly correlated to biological processes.

Identification of species adulteration in traded medicinal plant raw drugs using DNA barcoding.

Science.gov (United States)

Nithaniyal, Stalin; Vassou, Sophie Lorraine; Poovitha, Sundar; Raju, Balaji; Parani, Madasamy

2017-02-01

Plants are the major source of therapeutic ingredients in complementary and alternative medicine (CAM). However, species adulteration in traded medicinal plant raw drugs threatens the reliability and safety of CAM. Since morphological features of medicinal plants are often not intact in the raw drugs, DNA barcoding was employed for species identification. Adulteration in 112 traded raw drugs was tested after creating a reference DNA barcode library consisting of 1452 rbcL and matK barcodes from 521 medicinal plant species. Species resolution of this library was 74.4%, 90.2%, and 93.0% for rbcL, matK, and rbcL + matK, respectively. DNA barcoding revealed adulteration in about 20% of the raw drugs, and at least 6% of them were derived from plants with completely different medicinal or toxic properties. Raw drugs in the form of dried roots, powders, and whole plants were found to be more prone to adulteration than rhizomes, fruits, and seeds. Morphological resemblance, co-occurrence, mislabeling, confusing vernacular names, and unauthorized or fraudulent substitutions might have contributed to species adulteration in the raw drugs. Therefore, this library can be routinely used to authenticate traded raw drugs for the benefit of all stakeholders: traders, consumers, and regulatory agencies.

Patterns of plant species diversity during succession under different disturbance regimes.

Science.gov (United States)

Denslow, Julie Sloan

1980-07-01

I suggest that between-community variations in diversity patterns during succession in plant communities are due to the effects of selection on life history strategies under different disturbance regimes. Natural disturbances to plant communities are simultaneously a source of mortality for some individuals and a source of establishment sites for others. The plant community consists of a mosaic of disturbance patches (gaps) of different environmental conditions. The composition of the mosaic is described by the size-frequency distribution of the gaps and is dependent on the rates and scales of disturbance. The life-history strategies of plant species dependent on some form of disturbance for establishment of propagules should reflect this size-frequency distribution of disturbance patches. An extension of island biogeographic theory to encompass relative habitat area predicts that a community should be most rich in species adapted to growth and establishment in the spatially most common patch types. Changes in species diversity during succession following large scale disturbance reflect the prevalent life history patterns under historically common disturbance regimes. Communities in which the greatest patch area is in large-scale clearings (e.g. following fire) are most diverse in species establishing seedlings in xeric, high light conditions. Species diversity decreases during succession. Communities in which such large patches are rare are characterized by a large number of species that reach the canopy through small gaps and realtively few which regenerate in the large clearings. Diversity increases during succession following a large scale disturbance.Evidence from communities characterized by different disturbance regimes is summarized from the literature. This hypothesis provides an evolutionary mechanism with which to examine the changes in plant community structure during succession. Diversity peaks occurring at "intermediate levels" of disturbance as

Screening of plant species as ground cover on uranium mill tailings

International Nuclear Information System (INIS)

Venu Babu, P.; Eapen, S.

2012-01-01

The concept of construction of dams or holding areas for uranium mill tailings is relatively new in India and to date there is only one such facility being maintained by Uranium Corporation of India Limited (UCIL) at Jaduguda in Jharkhand. Due to the residual nature of radionuclides, chiefly uranium and its daughter products, special emphasis is given to the engineering aspects of the mill tailings ponds so as to ensure safety to general public for at least 200 years. Once a mill tailings pond reaches to its full capacity, creation of barrier layers over the mill tailings to prevent seepage of rain water and also erosion of mill tailings due to wind and water are advocated and a number of procedures are followed worldwide. Taking the extraordinary period of public safety to be assured, providing soil covers along with contouring and appropriate slopes over which vegetation is grown is gaining popularity. The vegetation not only reduces the impact of rain water hitting the soil cover, thereby reducing the soil erosion, but also lowers the moisture in the soil cover by extensive evapotranspiration, ensuring long term hydrological separation of the mill tailings underneath. Based on set criteria, applicable to the field scenario of mill tailings, a screening experiment was conducted under pot culture conditions to evaluate the survival and growth of different plant species. The plants after germination and hardening were transplanted into beakers containing mill tailings and periodical measurements on appropriate morphological characteristics such as plant height, length of twiners, number of tillers and number of leaves were recorded and evaluated. Of the twenty species tested in mill tailings, significant differences were noticed in the vigour of growth and several plant species could indeed establish well completing their life cycle including flowering and seed setting. Further, several leguminous species could also produce root nodules. It appears that the

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

African Journals Online (AJOL)

A survey of plant species and their families present in auto mechanic workshops in Benin City and Asaba was carried out. The frequency of occurrence of plants in the sites visited was used to determine prevalence. Peperomia pellucida occurred most in all the sites visited with a 55% frequency. The high rate of occurrence ...

Biological Invasion Influences the Outcome of Plant-Soil Feedback in the Invasive Plant Species from the Brazilian Semi-arid.

Science.gov (United States)

de Souza, Tancredo Augusto Feitosa; de Andrade, Leonaldo Alves; Freitas, Helena; da Silva Sandim, Aline

2017-05-30

Plant-soil feedback is recognized as the mutual interaction between plants and soil microorganisms, but its role on the biological invasion of the Brazilian tropical seasonal dry forest by invasive plants still remains unclear. Here, we analyzed and compared the arbuscular mycorrhizal fungi (AMF) communities and soil characteristics from the root zone of invasive and native plants, and tested how these AMF communities affect the development of four invasive plant species (Cryptostegia madagascariensis, Parkinsonia aculeata, Prosopis juliflora, and Sesbania virgata). Our field sampling revealed that AMF diversity and frequency of the Order Diversisporales were positively correlated with the root zone of the native plants, whereas AMF dominance and frequency of the Order Glomerales were positively correlated with the root zone of invasive plants. We grew the invasive plants in soil inoculated with AMF species from the root zone of invasive (I changed ) and native (I unaltered ) plant species. We also performed a third treatment with sterilized soil inoculum (control). We examined the effects of these three AMF inoculums on plant dry biomass, root colonization, plant phosphorous concentration, and plant responsiveness to mycorrhizas. We found that I unaltered and I changed promoted the growth of all invasive plants and led to a higher plant dry biomass, mycorrhizal colonization, and P uptake than control, but I changed showed better results on these variables than I unaltered . For plant responsiveness to mycorrhizas and fungal inoculum effect on plant P concentration, we found positive feedback between changed-AMF community (I changed ) and three of the studied invasive plants: C. madagascariensis, P. aculeata, and S. virgata.

Organic, integrated and conventional management in apple orchards: effect on plant species composition, richness and diversity

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Zdeňka Lososová

2011-01-01

Full Text Available The study was conducted to assess the effect of conventional, integrated and organic management on differences in plant species composition, richness and diversity. The plants were studied in triads of orchards situated in three regions of the Czech Republic. Data about species occurrences were collected on 15 permanent plots in the tree rows and 15 plots between tree rows in each of the apple orchards during 2009. A total of 201 vascular plant species (127 native species, 65 archaeophytes, and 9 neophytes were found. Management type and also different regional conditions had a significant effect on plant species composition and on diversity parameters of orchard spontaneous vegetation. Species richness and species pool was significantly higher in the organic orchards than in the differently managed orchards. Management type had significant effect on proportions of archaeophytes, and also neophytes in apple orchards. The results showed that a change from conventional to integrated and organic management in apple orchards lead to higher plant species diversity and to changes in plant species composition.

Examining the Spectral Separability of Prosopis glandulosa from Co-Existent Species Using Field Spectral Measurement and Guided Regularized Random Forest

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Nyasha Mureriwa

2016-02-01

Full Text Available The invasive taxa of Prosopis is rated the world’s top 100 unwanted species, and a lack of spatial data about the invasion dynamics has made the current control and monitoring methods unsuccessful. This study thus tests the use of in situ spectroscopy data with a newly-developed algorithm, guided regularized random forest (GRRF, to spectrally discriminate Prosopis from coexistent acacia species (Acacia karroo, Acacia mellifera and Ziziphus mucronata in the arid environment of South Africa. Results show that GRRF was able to reduce the high dimensionality of the spectroscopy data and select key wavelengths (n = 11 for discriminating amongst the species. These wavelengths are located at 356.3 nm, 468.5 nm, 531.1 nm, 665.2 nm, 1262.3 nm, 1354.1 nm, 1361.7 nm, 1376.9 nm, 1407.1 nm, 1410.9 nm and 1414.6 nm. The use of these selected wavelengths increases the overall classification accuracy from 79.19% and a Kappa value of 0.7201 when using all wavelengths to 88.59% and a Kappa of 0.8524 when the selected wavelengths were used. Based on our relatively high accuracies and ease of use, it is worth considering the GRRF method for reducing the high dimensionality of spectroscopy data. However, this assertion should receive considerable additional testing and comparison before it is accepted as a substitute for reliable high dimensionality reduction.

Tree-Dwelling Ants: Contrasting Two Brazilian Cerrado Plant Species without Extrafloral Nectaries

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Jonas Maravalhas

2012-01-01

Full Text Available Ants dominate vegetation stratum, exploiting resources like extrafloral nectaries (EFNs and insect honeydew. These interactions are frequent in Brazilian cerrado and are well known, but few studies compare ant fauna and explored resources between plant species. We surveyed two cerrado plants without EFNs, Roupala montana (found on preserved environments of our study area and Solanum lycocarpum (disturbed ones. Ants were collected and identified, and resources on each plant noted. Ant frequency and richness were higher on R. montana (67%; 35 spp than S. lycocarpum (52%; 26, the occurrence of the common ant species varied between them, and similarity was low. Resources were explored mainly by Camponotus crassus and consisted of scale insects, aphids, and floral nectaries on R. montana and two treehopper species on S. lycocarpum. Ants have a high diversity on cerrado plants, exploring liquid and prey-based resources that vary in time and space and affect their presence on plants.

Impacts of invasive nonnative plant species on the rare forest herb Scutellaria montana

Science.gov (United States)

Sikkema, Jordan J.; Boyd, Jennifer N.

2015-11-01

Invasive plant species and overabundant herbivore populations have the potential to significantly impact rare plant species given their increased risk for local extirpation and extinction. We used interacting invasive species removal and grazer exclusion treatments replicated across two locations in an occurrence of rare Scutellaria montana (large-flowered skullcap) in Chattanooga, Tennessee, USA, to assess: 1) competition by invasive Ligustrum sinense (Chinese privet) and Lonicera japonica (Japanese honeysuckle) and 2) the role of invasive species in mediating Oedocoilus virginianus (white-tailed deer) grazing of S. montana. Contrary to our hypothesis that invasive species presence would suppress S. montana directly via competition, S. montana individuals experienced a seasonal increase in stem height when invasive species were intact but not when invasive species were removed. Marginally significant results indicated that invasive species may afford S. montana protection from grazers, and we suggest that invasive species also could protect S. montana from smaller herbivores and/or positively influence abiotic conditions. In contrast to growth responses, S. montana individuals protected from O. virginianus exhibited a decrease in flowering between seasons relative to unprotected plants, but invasive species did not affect this variable. Although it has been suggested that invasive plant species may negatively influence S. montana growth and fecundity, our findings do not support related concerns. As such, we suggest that invasive species eradication efforts in S. montana habitat could be more detrimental than positive due to associated disturbance. However, the low level of invasion of our study site may not be representative of potential interference in more heavily infested habitat.

Coexisting diseases of moyamoya vasculopathy.

Science.gov (United States)

Wei, Yi-Chia; Liu, Chi-Hung; Chang, Ting-Yu; Chin, Shy-Chyi; Chang, Chien-Hung; Huang, Kuo-Lun; Chang, Yeu-Jhy; Peng, Tsung-I; Lee, Tsong-Hai

2014-07-01

Several coexisting diseases have been reported in patients with moyamoya vasculopathy (MMV), but studies of quasi-moyamoya disease (quasi-MMD) are rare. This study aims to investigate the frequency of known coexisting diseases in patients with quasi-MMD and to compare quasi-MMD with moyamoya disease (MMD). Between 2000 and 2011, we retrospectively screened patients with International Classification of Diseases, Ninth Revision, code of 4375 (MMD) in the Health Information System of our hospital. The vascular images of each patient were confirmed by 2 neurologists and 1 neuroradiologist based on the diagnostic criteria of Japan Ministry of Health and Welfare. We excluded the patients with missing images and erroneous diagnosis. Demographics, coexisting diseases, laboratory data, treatment, and recurrent strokes were recorded. The eligible patients were divided into quasi-MMD and MMD groups according to the presence or absence of coexisting diseases. MMV was found in 90 patients including 37 (41.1%) quasi-MMD and 53 (58.9%) MMD. Atherosclerosis (32.4%) and thyroid disease (29.7%) were the leading coexisting diseases in quasi-MMD. Patients with MMD became symptomatic in a bimodal age distribution, whereas patients with quasi-MMD became symptomatic in a single-peak distribution. The prognosis of recurrent strokes was similar between quasi-MMD and MMD based on Kaplan-Meier analysis. A bimodal distribution of onset age was noted in MMD, whereas a single-peak distribution was found in quasi-MMD. Coexisting diseases were usually underevaluated but were more common than expected in patients with MMV. Atherosclerosis and thyroid diseases were the leading coexisting diseases in different preferential age. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Number of endemic and native plant species in the Galapagos Archipelago in relation to geographical parameters

DEFF Research Database (Denmark)

Willerslev, Eske; Hansen, Anders J.; Nielsen, Kirstine Klitgaard

2002-01-01

By simple and multiple regression analyses we investigate updated species numbers of endemic and native vascular plants and seed plants in the Galapagos Archipelago in relation to geographical parameters. We find that the best models to describe species numbers are regression models with log......-transformed species numbers as dependent and log-transformed modified area (i.e. area not covered with barren lava) as an independent variable. This holds both for total species number, for native species number, for endemic species number and for total number of seed plants as well as number of endemic seed plants...

Morphological similarity and ecological overlap in two rotifer species.

Science.gov (United States)

Gabaldón, Carmen; Montero-Pau, Javier; Serra, Manuel; Carmona, María José

2013-01-01

Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology-some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1) functional response, expressed by clearance rates; (2) tolerance to starvation, measured by growth and reproduction; and (3) vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not based on

Morphological similarity and ecological overlap in two rotifer species.

Directory of Open Access Journals (Sweden)

Carmen Gabaldón

Full Text Available Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention, these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology-some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1 functional response, expressed by clearance rates; (2 tolerance to starvation, measured by growth and reproduction; and (3 vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not

Plant species responses to oil degradation and toxicity reduction in ...

African Journals Online (AJOL)

Vegetated plots were established by planting different plant species – legumes and vegetable (Abelmoschus, esculentus, Telfaria occidentalis and Vigna unguiculata) and applied with sawdust and chromolaena leaves at different intensities of oil pollution. Toxicity of the soil was evaluated using germination percentage, ...

Plant species from coal mine overburden dumping site in Satui, South Kalimantan, Indonesia

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Vivi Novianti

2017-07-01

Full Text Available Coal mine overburden (OB materials were nutrient-poor, loosely adhered particles of shale, stones, boulders, and cobbles, also contained elevated concentration of trace metals. This condition cause OB substrate did not support plants growth. However, there were certain species that able to grow on overburden dumping site. This investigation sought to identify plants species that presence on coal mine overburden. The research was conducted on opencast coal mine OB dumping site in Satui, South Kalimantan. Vegetation sampling was carried out on six different ages of coal mine OB dumps (7, 10, 11, 42, 59 and 64 month using line transect. Species identification used information from local people, AMDAL report of PT Arutmin Indonesia-Satui mine project, and website. There were 123 plant species, consisted of 79 herbs (Cyperaceae, Poaceae and Asteraceae, 10 lianes, bryophyte, 9 ferns, 10 shrubs, and 14 trees. A number of Poaceae, i.e., Paspalumconjugatum, Paspalumdilatatum, and Echinochloacolona generally present among the stones, boulders, and cobbles. While Cyperaceae such as Fimbristylis miliaceae, Cyperus javanicus, Rhyncospora corymbosa and Scleria sumatrensis most often foundinand around thebasin/pond with its smooth and humid substrate characteristics. Certain species of shrubs and trees present on the 7 month OB dumping site. They wereChromolaena odorata, Clibadium surinamense, Melastoma malabathricum, Trema micrantha, and Solanum torvum (Shrubs, Ochroma pyramidale and Homalanthus populifolius (trees. This plant species could be used for accelerating primary succession purpose on coal mine overburden dumping site. Nevertheless, species selection was needed to avoid planting invasive species.

REMOTE DETENTION OF INVASIVE AND OPPORTUNISTIC PLANT SPECIES IN GREAT LAKES COASTAL WETLANDS

Science.gov (United States)

Invasive and opportunistic plant species have been associated with wetland disturbance. Increases in the abundance of plant species such as common reed (Phragmites australis) in coastal Great Lakes wetlands are hypothesized to occur with shifts toward drier hydrologic regimes, fr...

Plant DNA barcodes can accurately estimate species richness in poorly known floras.

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Craig Costion

Full Text Available BACKGROUND: Widespread uptake of DNA barcoding technology for vascular plants has been slow due to the relatively poor resolution of species discrimination (∼70% and low sequencing and amplification success of one of the two official barcoding loci, matK. Studies to date have mostly focused on finding a solution to these intrinsic limitations of the markers, rather than posing questions that can maximize the utility of DNA barcodes for plants with the current technology. METHODOLOGY/PRINCIPAL FINDINGS: Here we test the ability of plant DNA barcodes using the two official barcoding loci, rbcLa and matK, plus an alternative barcoding locus, trnH-psbA, to estimate the species diversity of trees in a tropical rainforest plot. Species discrimination accuracy was similar to findings from previous studies but species richness estimation accuracy proved higher, up to 89%. All combinations which included the trnH-psbA locus performed better at both species discrimination and richness estimation than matK, which showed little enhanced species discriminatory power when concatenated with rbcLa. The utility of the trnH-psbA locus is limited however, by the occurrence of intraspecific variation observed in some angiosperm families to occur as an inversion that obscures the monophyly of species. CONCLUSIONS/SIGNIFICANCE: We demonstrate for the first time, using a case study, the potential of plant DNA barcodes for the rapid estimation of species richness in taxonomically poorly known areas or cryptic populations revealing a powerful new tool for rapid biodiversity assessment. The combination of the rbcLa and trnH-psbA loci performed better for this purpose than any two-locus combination that included matK. We show that although DNA barcodes fail to discriminate all species of plants, new perspectives and methods on biodiversity value and quantification may overshadow some of these shortcomings by applying barcode data in new ways.

Habitat types on the Hanford Site: Wildlife and plant species of concern

Energy Technology Data Exchange (ETDEWEB)

Downs, J.L.; Rickard, W.H.; Brandt, C.A. [and others

1993-12-01

The objective of this report is to provide a comprehensive source of the best available information on Hanford Site sensitive and critical habitats and plants and animals of importance or special status. In this report, sensitive habitats include areas known to be used by threatened, endangered, or sensitive plant or animal species, wetlands, preserves and refuges, and other sensitive habitats outlined in the Hanford Site Baseline Risk Assessment Methodology. Potentially important species for risk assessment and species of special concern with regard to their status as threatened, endangered, or sensitive are described, and potential habitats for these species identified.

ISOLATION AND CHARACTERIZATION OF CHITINASE GENE FROM THE UNTRADITIONAL PLANT SPECIES

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Dominika Ďurechová

2013-02-01

Full Text Available Round-leaf sundew (Drosera rotundifolia L. from Droseraceae family belongs among a few plant species with strong antifungal potential. It was previously shown that chitinases of carnivorous plant species may play role during the insect prey digestion, when hard chitin skeleton is being decomposed. As many phytopathogenic fungi contain chitin in their cell wall our attention in this work was focused on isolation and in silico characterization of genomic DNA sequence of sundew chitinase gene. Subsequently this gene was fused to strong constitutive CaMV35S promoter and cloned into the plant binary vector pBinPlus and tested in A. tumefaciens LBA 4404 for its stability. Next, when transgenic tobacco plants are obtained, increasing of their antifungal potential will be tested.

How directional mobility affects coexistence in rock-paper-scissors models

Science.gov (United States)

Avelino, P. P.; Bazeia, D.; Losano, L.; Menezes, J.; de Oliveira, B. F.; Santos, M. A.

2018-03-01

This work deals with a system of three distinct species that changes in time under the presence of mobility, selection, and reproduction, as in the popular rock-paper-scissors game. The novelty of the current study is the modification of the mobility rule to the case of directional mobility, in which the species move following the direction associated to a larger (averaged) number density of selection targets in the surrounding neighborhood. Directional mobility can be used to simulate eyes that see or a nose that smells, and we show how it may contribute to reduce the probability of coexistence.

A simple and efficient method for isolating small RNAs from different plant species

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de Folter Stefan

2011-02-01

Full Text Available Abstract Background Small RNAs emerged over the last decade as key regulators in diverse biological processes in eukaryotic organisms. To identify and study small RNAs, good and efficient protocols are necessary to isolate them, which sometimes may be challenging due to the composition of specific tissues of certain plant species. Here we describe a simple and efficient method to isolate small RNAs from different plant species. Results We developed a simple and efficient method to isolate small RNAs from different plant species by first comparing different total RNA extraction protocols, followed by streamlining the best one, finally resulting in a small RNA extraction method that has no need of first total RNA extraction and is not based on the commercially available TRIzol® Reagent or columns. This small RNA extraction method not only works well for plant tissues with high polysaccharide content, like cactus, agave, banana, and tomato, but also for plant species like Arabidopsis or tobacco. Furthermore, the obtained small RNA samples were successfully used in northern blot assays. Conclusion Here we provide a simple and efficient method to isolate small RNAs from different plant species, such as cactus, agave, banana, tomato, Arabidopsis, and tobacco, and the small RNAs from this simplified and low cost method is suitable for downstream handling like northern blot assays.

Above- and below-ground effects of plant diversity depend on species origin

DEFF Research Database (Denmark)

Kuebbing, Sara E.; Classen, Aimee Taylor; Sanders, Nate

2015-01-01

-interaction models to describe how species' interactions influenced diversity-productivity relationships. Communities with more species had higher total biomass than did monoculture communities, but native and nonnative communities diverged in root : shoot ratios and the mechanism responsible for increased......Although many plant communities are invaded by multiple nonnative species, we have limited information on how a species' origin affects ecosystem function. We tested how differences in species richness and origin affect productivity and seedling establishment. We created phylogenetically paired...... native and nonnative plant communities in a glasshouse experiment to test diversity-productivity relationships and responsible mechanisms (i.e. selection or complementarity effects). Additionally, we tested how productivity and associated mechanisms influenced seedling establishment. We used diversity...

Quantum mechanical analogy for solving a competitive coexistence model in ecology

International Nuclear Information System (INIS)

Wio, H.S.; Kuperman, M.N.; Haeften, B. von

1994-07-01

We have studied an ecological system of three species: a strong and a weak one, competing for a single food resource, modelled as a reaction-diffusion process. An exact analytical solution has been found through a quantum mechanical analogy. Such solution indicates that in certain situations the classical results on extinction and coexistence of Lotka-Volterra type equations are no longer valid, essentially, as a consequence of the weak species mobility. A stability analysis of this solution against changes in different parameters has been carried out. (author). 19 refs, 5 figs

Species diversity of vascular plants in Si Phang-nga National Park, Phangnga Province

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Leeratiwong, C.

2005-07-01

Full Text Available A survey of the vascular plants in Si Phang-nga National Park, Phangnga Province, was conducted from September 2002 to August 2003. Five hundred and forty three species of 287 genera and 111 families were collected. The most diverse family was Rubiaceae, 53 species. Four species of these collected plants are endemic to Thailand, Argostemma lobulatum, Aristolochia helix, Crinum thaianum and Mallotus hymenophyllus and three species, Hedyotis hedyotidea, Lipocarpha microcephala and Pterolobium intergum are newly recorded for southern Thailand.

Biodegradation of 2,4-dinitrotoluene by different plant species.

Science.gov (United States)

Podlipná, Radka; Pospíšilová, Blanka; Vaněk, Tomáš

2015-02-01

Over the past century, rapid growth of population, mining and industrialization significantly contributed to extensive soil, air and water contamination. The 2,4-dinitrotoluene (2,4-DNT), used mostly as explosive, belongs to the hazardous xenobiotics. Soils and waters contaminated with 2,4-DNT may be cleaned by phytoremediation using suitable plant species. The ability of crop plants (hemp, flax, sunflower and mustard) to germinate and grow on soils contaminated with 2,4-DNT was compared. Stimulation of their growth was found at 0.252 mg/g 2,4-DNT. The lethal concentration for the growth for these species was around 1 mg/g. In hydropony, the above mentioned species were able to survive 200 mg/l 2,4-DNT, the concentration close to maximal solubility of 2,4-DNT in water. Metabolism of 2,4-DNT was tested using suspension culture of soapwort and reed. The degradation products 2-aminonitrotoluene and 4-aminonitrotoluene were found both in the medium and in the acetone extract of plant cells. The test showed that the toxicity of these metabolites was higher than the toxicity of the parent compound, but 2,4-diaminotoluene, the product of next reduction step, was less toxic in the concentration range tested (0-200 mg/l). Copyright © 2014. Published by Elsevier Inc.

Plant-soil feedbacks and the coexistence of competing plants

NARCIS (Netherlands)

Revilla, T.A.; Veen, G.F.; Eppinga, M.B.; Weissing, F.J.

2013-01-01

Plant–soil feedbacks can have important implications for the interactions among plants. Understanding these effects is a major challenge since it is inherently difficult to measure and manipulate highly diverse soil communities. Mathematical models may advance this understanding by making the

Plant-soil feedbacks and the coexistence of competing plants

NARCIS (Netherlands)

Revilla, T.A.; Veen, G.F.; Eppinga, M.B.; Weissing, F.J.

Plant–soil feedbacks can have important implications for the interactions among plants. Understanding these effects is a major challenge since it is inherently difficult to measure and manipulate highly diverse soil communities. Mathematical models may advance this understanding by making the

Diversity and aggregation patterns of plant species in a grass community

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Ran Li

2014-09-01

Full Text Available Both composition and aggregation patterns of species in a community are the outcome of community self-organizing. In this paper we conducted analysis on species diversity and aggregation patterns of plant species in a grass community, Zhuhai, China. According to the sampling survey, in total of 47 plant species, belonging to 16 families, were found. Compositae had 10 species (21.3%, seconded by Gramineae (9 species, 19.1%, Leguminosae (6 species, 12.8%, Cyperaceae (4 species, 8.5%, and Malvaceae (3 species, 6.4%. The results revealed that the means of aggregation indices Iδ, I and m*/m were 21.71, 15.71 and 19.89 respectively and thus individuals of most of plant species strongly followed aggregative distribution. Iwao analysis indicated that both individuals of all species and clumps of all individuals of all species followed aggregative distribution. Taylor's power law indicated that individuals of all species followed aggregative distribution and aggregation intensity strengthened as the increase of mean density. We held that the strong aggregation intensity of a species has been resulted from the strong adaptation ability to the environment, the strong interspecific competition ability and the earlier establishment of the species. Fitting goodness of the mean, I, Iδ, m*/m with probability distributions demonstrated that the mean (density, I, Iδ, and m*/m over all species followed Weibull distribution rather than normal distribution. Lophatherum gracile, Paederia scandens (Lour. Merr., Eleusine indica, and Alternanthera philoxeroides (Mart. Griseb. were mostly aggregative, and Oxalis sp., Eleocharis plantagineiformis, Vernonia cinerea (L. Less., and Sapium sebiferum (L. Roxb, were mostly uniform in the spatial distribution. Importance values (IV showed that Cynodon dactylon was the most important species, seconded by Desmodium triflorum (L. DC., Cajanus scarabaeoides (L. Benth., Paspalum scrobiculatum L., and Rhynchelytrum repens. Oxalis

Habitat Heterogeneity Affects Plant and Arthropod Species Diversity and Turnover in Traditional Cornfields.

Science.gov (United States)

Martínez, Eliana; Rös, Matthias; Bonilla, María Argenis; Dirzo, Rodolfo

2015-01-01

The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity.

Ecological Performances of Plant Species of Halophilous Hydromorphic Ecosystems

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Maria Speranza

2015-12-01

Full Text Available Coastal wetlands are very special environments, characterized by soils permanently or seasonally saturated by salt or brackish water. They host microorganisms and plants able to adapt to anoxic conditions. This paper proposes a review of recent scientific papers dealing with the study of coastal wetlands from different points of view. Some studies examine the species composition and the pattern of the spatial distribution of plant communities, depending on the depth of the salt water table, as well as on other related factors. A significant number of studies analyse instead the coastal wetlands in their ability for the phytoremediation (phytostabilisation and/or phytoextraction and highlight the importance of interactions between the rhizosphere of the halophytes and the physical environment. Finally, more recent studies consider the plant species of the coastal wetlands as a source of useful products (food, feed, oils and expose the results of promising researches on their cultivation.

Threatened plant species of the Nevada Test Site, Ash Meadows, central-southern Nevada

Energy Technology Data Exchange (ETDEWEB)

Beatley, J.C.

1977-04-01

This report is a companion one to Endangered Plant Species of the Nevada Test Site, Ash Meadows, and Central-Southern Nevada (COO-2307-11) and deals with the threatened plant species of the same area. The species are those cited in the Federal Register, July 1, 1975, and include certain ones listed as occurring only in California or Arizona, but which occur also in central-southern Nevada. As with the earlier report, the purpose of this one is to record in detail the location of the past plant collections which constitute the sole or principal basis for defining the species' distributions and frequency of occurrence in southern Nye County, Nevada, and to recommend the area of the critical habitat where this is appropriate. Many of the species occur also in southern California, and for these the central-southern Nevada records are presented for consideration of the overall status of the species throughout its range.

Which species? A decision-support tool to guide plant selection in stormwater biofilters

Science.gov (United States)

Payne, Emily G. I.; Pham, Tracey; Deletic, Ana; Hatt, Belinda E.; Cook, Perran L. M.; Fletcher, Tim D.

2018-03-01

Plant species are diverse in form, function and environmental response. This provides enormous potential for designing nature-based stormwater treatment technologies, such as biofiltration systems. However, species can vary dramatically in their pollutant-removal performance, particularly for nitrogen removal. Currently, there is a lack of information on how to efficiently select from the vast palette of species. This study aimed to identify plant traits beneficial to performance and create a decision-support tool to screen species for further testing. A laboratory experiment using 220 biofilter columns paired plant morphological characteristics with nitrogen removal and water loss for 20 Australian native species and two lawn grasses. Testing was undertaken during wet and dry conditions, for two biofilter designs (saturated zone and free-draining). An extensive root system and high total biomass were critical to the effective removal of total nitrogen (TN) and nitrate (NO3-), driven by high nitrogen assimilation. The same characteristics were key to performance under dry conditions, and were associated with high water use for Australian native plants; linking assimilation and transpiration. The decision-support tool uses these scientific relationships and readily-available information to identify the morphology, natural distribution and stress tolerances likely to be good predictors of plant nitrogen and water uptake.

Species richness of vascular plants, bryophytes, and lichens along an altitudinal gradient in western Norway

Science.gov (United States)

Grytnes, John Arvid; Heegaard, Einar; Ihlen, Per G.

2006-05-01

Species richness patterns of ground-dwelling vascular plants, bryophytes, and lichens were compared along an altitudinal gradient (310-1135 m a.s.l.), in western Norway. Total species richness peaked at intermediate altitudes, vascular plant species richness peaked immediately above the forest limit (at 600-700 m a.s.l.), bryophyte species richness had no statistically significant trend, whereas lichen richness increased from the lowest point and up to the forest limit, with no trend above. It is proposed that the pattern in vascular plant species richness is enhanced by an ecotone effect. Bryophyte species richness responds to local scale factors whereas the lichen species richness may be responding to the shading from the forest trees.

How does biomass distribution change with size and differ among species? An analysis for 1200 plant species from five continents.

Science.gov (United States)

Poorter, Hendrik; Jagodzinski, Andrzej M; Ruiz-Peinado, Ricardo; Kuyah, Shem; Luo, Yunjian; Oleksyn, Jacek; Usoltsev, Vladimir A; Buckley, Thomas N; Reich, Peter B; Sack, Lawren

2015-11-01

We compiled a global database for leaf, stem and root biomass representing c. 11 000 records for c. 1200 herbaceous and woody species grown under either controlled or field conditions. We used this data set to analyse allometric relationships and fractional biomass distribution to leaves, stems and roots. We tested whether allometric scaling exponents are generally constant across plant sizes as predicted by metabolic scaling theory, or whether instead they change dynamically with plant size. We also quantified interspecific variation in biomass distribution among plant families and functional groups. Across all species combined, leaf vs stem and leaf vs root scaling exponents decreased from c. 1.00 for small plants to c. 0.60 for the largest trees considered. Evergreens had substantially higher leaf mass fractions (LMFs) than deciduous species, whereas graminoids maintained higher root mass fractions (RMFs) than eudicotyledonous herbs. These patterns do not support the hypothesis of fixed allometric exponents. Rather, continuous shifts in allometric exponents with plant size during ontogeny and evolution are the norm. Across seed plants, variation in biomass distribution among species is related more to function than phylogeny. We propose that the higher LMF of evergreens at least partly compensates for their relatively low leaf area : leaf mass ratio. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Wild plant species growing closely connected in a subalpine meadow host distinct root-associated bacterial communities

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Kristin Aleklett

2015-02-01

Full Text Available Plant roots are known to harbor large and diverse communities of bacteria. It has been suggested that plant identity can structure these root-associated communities, but few studies have specifically assessed how the composition of root microbiota varies within and between plant species growing under natural conditions. We assessed the community composition of endophytic and epiphytic bacteria through high throughput sequencing using 16S rDNA derived from root tissues collected from a population of a wild, clonal plant (Orange hawkweed–Pilosella aurantiaca as well as two neighboring plant species (Oxeye daisy–Leucanthemum vulgare and Alsike clover–Trifolium hybridum. Our first goal was to determine if plant species growing in close proximity, under similar environmental conditions, still hosted unique root microbiota. Our results showed that plants of different species host distinct bacterial communities in their roots. In terms of community composition, Betaproteobacteria (especially the family Oxalobacteraceae were found to dominate in the root microbiota of L. vulgare and T. hybridum samples, whereas the root microbiota of P. aurantiaca had a more heterogeneous distribution of bacterial abundances where Gammaproteobacteria and Acidobacteria occupied a larger portion of the community. We also explored the extent of individual variance within each plant species investigated, and found that in the plant species thought to have the least genetic variance among individuals (P. aurantiaca still hosted just as diverse microbial communities. Whether all plant species host their own distinct root microbiota and plants more closely related to each other share more similar bacterial communities still remains to be fully explored, but among the plants examined in this experiment there was no trend that the two species belonging to the same family shared more similarities in terms of bacterial community composition.

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

Improving intercropping: a synthesis of research in agronomy, plant physiology and ecology.

Science.gov (United States)

Brooker, Rob W; Bennett, Alison E; Cong, Wen-Feng; Daniell, Tim J; George, Timothy S; Hallett, Paul D; Hawes, Cathy; Iannetta, Pietro P M; Jones, Hamlyn G; Karley, Alison J; Li, Long; McKenzie, Blair M; Pakeman, Robin J; Paterson, Eric; Schöb, Christian; Shen, Jianbo; Squire, Geoff; Watson, Christine A; Zhang, Chaochun; Zhang, Fusuo; Zhang, Junling; White, Philip J

2015-04-01

Intercropping is a farming practice involving two or more crop species, or genotypes, growing together and coexisting for a time. On the fringes of modern intensive agriculture, intercropping is important in many subsistence or low-input/resource-limited agricultural systems. By allowing genuine yield gains without increased inputs, or greater stability of yield with decreased inputs, intercropping could be one route to delivering ‘sustainable intensification’. We discuss how recent knowledge from agronomy, plant physiology and ecology can be combined with the aim of improving intercropping systems. Recent advances in agronomy and plant physiology include better understanding of the mechanisms of interactions between crop genotypes and species – for example, enhanced resource availability through niche complementarity. Ecological advances include better understanding of the context-dependency of interactions, the mechanisms behind disease and pest avoidance, the links between above- and below-ground systems, and the role of microtopographic variation in coexistence. This improved understanding can guide approaches for improving intercropping systems, including breeding crops for intercropping. Although such advances can help to improve intercropping systems, we suggest that other topics also need addressing. These include better assessment of the wider benefits of intercropping in terms of multiple ecosystem services, collaboration with agricultural engineering, and more effective interdisciplinary research.

Plant species richness regulates soil respiration through changes in productivity

NARCIS (Netherlands)

Dias, A.A.; Ruijven, van J.; Berendse, F.

2010-01-01

Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of

Plant species richness regulates soil respiration through changes in productivity.

NARCIS (Netherlands)

Tavares Correa Dias, A.; van Ruijven, J.; Berendse, F.

2010-01-01

Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of

A global comparison of the nutritive values of forage plants grown in contrasting environments.

Science.gov (United States)

Lee, Mark A

2018-03-17

Forage plants are valuable because they maintain wild and domesticated herbivores, and sustain the delivery of meat, milk and other commodities. Forage plants contain different quantities of fibre, lignin, minerals and protein, and vary in the proportion of their tissue that can be digested by herbivores. These nutritive components are important determinants of consumer growth rates, reproductive success and behaviour. A dataset was compiled to quantify variation in forage plant nutritive values within- and between-plant species, and to assess variation between plant functional groups and bioclimatic zones. 1255 geo-located records containing 3774 measurements of nutritive values for 136 forage plant species grown in 30 countries were obtained from published articles. Spatial variability in forage nutritive values indicated that climate modified plant nutritive values. Forage plants grown in arid and equatorial regions generally contained less digestible material than those grown in temperate and tundra regions; containing more fibre and lignin, and less protein. These patterns may reveal why herbivore body sizes, digestion and migration strategies are different in warmer and drier regions. This dataset also revealed the capacity for variation in the nutrition provided by forage plants, which may drive consumer species coexistence. The proportion of the plant tissue that was digestible ranged between species from 2 to 91%. The amount of fibre contained within plant material ranged by 23-90%, protein by 2-36%, lignin by 1-21% and minerals by 2-22%. On average, grasses and tree foliage contained the most fibre, whilst herbaceous legumes contained the most protein and tree foliage contained the most lignin. However, there were individual species within each functional group that were highly nutritious. This dataset may be used to identify forage plant species or mixtures of species from different functional groups with useful nutritional traits which can be cultivated

Patterns of among- and within-species variation in heterospecific pollen receipt: The importance of ecological generalization.

Science.gov (United States)

Arceo-Gómez, Gerardo; Abdala-Roberts, Luis; Jankowiak, Anneka; Kohler, Clare; Meindl, George A; Navarro-Fernández, Carmen M; Parra-Tabla, Víctor; Ashman, Tia-Lynn; Alonso, Conchita

2016-03-01

Coflowering plants are at risk for receiving pollen from heterospecifics as well as conspecifics, yet evidence shows wide variation in the degree that heterospecific pollen transfer occurs. Evaluation of patterns and correlates of among- and within-species variation in heterospecific pollen (HP) receipt is key to understanding its importance for floral evolution and species coexistence; however, the rarity of deeply sampled multispecies comparisons has precluded such an evaluation. We evaluated patterns of among- and within-species variation in HP load size and diversity in 19 species across three distinct plant communities. We assessed the importance of phenotypic specialization (floral phenotype), ecological specialization (contemporary visitor assemblage), and conspecific flower density as determinants of among-species variation. We present hypotheses for different accrual patterns of HP within species based on the evenness and quality of floral visitors and evaluated these by characterizing the relationship between conspecific pollen (CP) and HP receipt. We found that within-species variation in HP receipt was greater than among-species and among-communities variation. Among species, ecological generalization emerged as the strongest driver of variation in HP receipt irrespective of phenotypic specialization. Within-species variation in HP load size and diversity was predicted most often from two CP-HP relationships (linear or exponentially decreasing), suggesting that two distinct types of plant-pollinator interactions prevail. Our results give important insights into the potential drivers of among- and within-species variation in HP receipt. They also highlight the value of explorations of patterns at the intraspecific level, which can ultimately shed light on plant-pollinator-mediated selection in diverse plant communities. © 2016 Botanical Society of America.

[Regenerative morphological traits in a woody species community in Tumbesian tropical dry forest].

Science.gov (United States)

Romero-Saritama, José Miguel; Pérez-Rúuz, César

2016-06-01

morphological traits occur among the studied woody plants of the Tumbesian dry forest. The latter favors a plethora of behavioral mechanisms to coexist among woody species of the dry forest in response to the environmental stress that is typical of arid areas.

Ecological studies of plants for the control of environmental pollution. IV. Growth of various plant species as influenced by soil applied cadmium

Energy Technology Data Exchange (ETDEWEB)

Cha, J.W.; Kim, B.W.

1975-03-01

The relations of the growth response of plants, i.e. 4 species of crops, 12 species of roadside trees and 5 species of horticultural plants to cadmium (Cd) were studied in pot cultures. Growth in dry weight of corn, soybeans, barley, and wheat plants was decreased with an increase in Cd concentration. Damage to corn plants caused by Cd treatment was more or less recovered when it was grown in soil with calcium, but the other three crops did not recover. Although crop plants used here absorbed a small amount of Cd through the roots, the Cd content in the shoots was directly proportionate to the concentration of Cd added to the soil. Additions of calcium and sulfur to soil were sufficient to change the soil pH. The chlorosis on leaves caused by Cd treatment was observed in 2 species such as Euonymus japonica and Rhododendron yedoense out of 5 species of the horticultural plants, especially at 50 ppm of Cd. Euonymus japonica had symptoms of chlorosis and defoliation, and at higher concentrations the symptoms were more severe. At 200 ppm of Cd little damage was observed in Pinus koraiensis and Ginkgo biloba, but severe chlorosis was observed in Robinia pseudoacacia and Sabina chinensis, Buxus koreana, Abies holophylla and Platanus orientalis. Nevertheless, those plants that had serious damage at 200 ppm of Cd showed weakened symptoms by adding calcium to the soil. There were many Cd tolerant species out of the plants used in this experiment, such as Crassula falcata, Chrysanthemum morifolium, Hibiscus syriacus, Ligustrum ovalifolium, Liriodendron tulipeferia, and Lespedeza crytobotrys.

Application of two way indicator species analysis in lowland plant types classification.

Science.gov (United States)

Kooch, Yahya; Jalilvand, Hamid; Bahmanyar, Mohammad Ali; Pormajidian, Mohammad Reza

2008-03-01

A TWINSPAN classification of 60 sample plots from the Khanikan forest (North of Iran) is presented. Plant types were determined from field observations and sample plot data arranged and analyzed in association tables. The types were defined on the basis of species patterns of presence, absence and coverage values. Vegetation was sampled with randomized-systematic method. Vegetation data including density and cover percentage were estimated quantitatively within each quadrate and using the two-way indicator species analysis. The objectives of the study were to plant type's classification for Khanikan lowland forest in North of Iran, Identification of indicator species in plant types and increase our understanding in regarding to one of Multivariate analysis methods (TWINSPAN). Five plant types were produced for the study area by TWINSPAN, i.e., Menta aquatica, Oplismenus undulatifolius, Carex grioletia, Viola odarata and Rubus caesius. Therefore, at each step of the process, the program identifies indicator species that show strongly differential distributions between groups and so can severe to distinguish the groups. The final result, incorporating elements of classification can provide a compact and powerful summary of pattern in the data set.

Exotic plant species around Jeongeup Research Complex and RFT industrial complex

International Nuclear Information System (INIS)

Kim, Jin Kyu; Cha, Min Kyoung; Ryu, Tae Ho; Lee, Yun Jong; Kim, Jin Hong

2015-01-01

In Shinjeong-dong of Jeongeup, there are three government-supported research institutes and an RFT industrial complex which is currently being established. Increased human activities can affect flora and fauna as a man-made pressure onto the region. As a baseline study, status of exotic plants was investigated prior to a full operation of the RFT industrial complex. A total of 54 species and 1 variety of naturalized or introduced plants were found in the study area. Among them, three species (Ambrosia artemisifolia var. elatior, Rumex acetocella and Aster pilosus) belong to 'nuisance species', and four species (Phytolacca americana, Iopomoea hederacea, Ereechtites hieracifolia and Rudbeckia laciniata) to ‘monitor species’ designated by the ministry of Environment. Some of naturalized trees and plants were intentionally introduced in this area, while others naturally immigrated. Physalis angulata seems to immigrate in the study area in the form of mixture with animal feeds as its distribution coincided with the transportation route of the animal feeds. Liquidambar styraciflua is amenable to the ecological investigation on the possible expansion of the species to the nearby Naejang National Park as its leave shape and autumn color are very similar to those of maple trees. The number of naturalized plants around the RFT industrial complex will increase with an increase in floating population, in human activities in association with constructions of factories and operations of the complex. The result of this study provides baseline data for assessing the ecological change of the region according to the operation of the RFT industrial complex

Exotic plant species around Jeongeup Research Complex and RFT industrial complex

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Kyu; Cha, Min Kyoung; Ryu, Tae Ho; Lee, Yun Jong; Kim, Jin Hong [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup(Korea, Republic of)

2015-08-15

In Shinjeong-dong of Jeongeup, there are three government-supported research institutes and an RFT industrial complex which is currently being established. Increased human activities can affect flora and fauna as a man-made pressure onto the region. As a baseline study, status of exotic plants was investigated prior to a full operation of the RFT industrial complex. A total of 54 species and 1 variety of naturalized or introduced plants were found in the study area. Among them, three species (Ambrosia artemisifolia var. elatior, Rumex acetocella and Aster pilosus) belong to 'nuisance species', and four species (Phytolacca americana, Iopomoea hederacea, Ereechtites hieracifolia and Rudbeckia laciniata) to ‘monitor species’ designated by the ministry of Environment. Some of naturalized trees and plants were intentionally introduced in this area, while others naturally immigrated. Physalis angulata seems to immigrate in the study area in the form of mixture with animal feeds as its distribution coincided with the transportation route of the animal feeds. Liquidambar styraciflua is amenable to the ecological investigation on the possible expansion of the species to the nearby Naejang National Park as its leave shape and autumn color are very similar to those of maple trees. The number of naturalized plants around the RFT industrial complex will increase with an increase in floating population, in human activities in association with constructions of factories and operations of the complex. The result of this study provides baseline data for assessing the ecological change of the region according to the operation of the RFT industrial complex.

Plant-associated bacterial populations on native and invasive plant species: comparisons between 2 freshwater environments.

Science.gov (United States)

Olapade, Ola A; Pung, Kayleigh

2012-06-01

Plant-microbial interactions have been well studied because of the ecological importance of such relationships in aquatic systems. However, general knowledge regarding the composition of these biofilm communities is still evolving, partly as a result of several confounding factors that are attributable to plant host properties and to hydrodynamic conditions in aquatic environments. In this study, the occurrences of various bacterial phylogenetic taxa on 2 native plants, i.e., mayapple (Podophyllum peltatum L.) and cow parsnip (Heracleum maximum Bartram), and on an invasive species, i.e., garlic mustard (Alliaria petiolata (M. Bieb.) Cavara & Grande), were quantitatively examined using nucleic acid staining and fluorescence in situ hybridization. The plants were incubated in triplicates for about a week within the Kalamazoo River and Pierce Cedar Creek as well as in microcosms. The bacterial groups targeted for enumeration are known to globally occur in relatively high abundance and are also ubiquitously distributed in freshwater environments. Fluorescence in situ hybridization analyses of the bacterioplankton assemblages revealed that the majority of bacterial cells that hybridized with the different probes were similar between the 2 sites. In contrast, the plant-associated populations while similar on the 3 plants incubated in Kalamazoo River, their representations were highest on the 2 native plants relative to the invasive species in Pierce Cedar Creek. Overall, our results further suggested that epiphytic bacterial assemblages are probably under the influences of and probably subsequently respond to multiple variables and conditions in aquatic milieus.

Assessing plant community composition fails to capture impacts of white-tailed deer on native and invasive plant species.

Science.gov (United States)

Nuzzo, Victoria; Dávalos, Andrea; Blossey, Bernd

2017-07-01

Excessive herbivory can have transformative effects on forest understory vegetation, converting diverse communities into depauperate ones, often with increased abundance of non-native plants. White-tailed deer are a problematic herbivore throughout much of eastern North America and alter forest understory community structure. Reducing (by culling) or eliminating (by fencing) deer herbivory is expected to return understory vegetation to a previously diverse condition. We examined this assumption from 1992 to 2006 at Fermilab (Batavia, IL) where a cull reduced white-tailed deer ( Odocoileus virginianus ) abundance in 1998/1999 by 90 % from 24.6 to 2.5/km 2 , and at West Point, NY, where we assessed interactive effects of deer, earthworms, and invasive plants using 30 × 30 m paired fenced and open plots in 12 different forests from 2009 to 2012. We recorded not only plant community responses (species presence and cover) within 1 m 2 quadrats, but also responses of select individual species (growth, reproduction). At Fermilab, introduced Alliaria petiolata abundance initially increased as deer density increased, but then declined after deer reduction. The understory community responded to the deer cull by increased cover, species richness and height, and community composition changed but was dominated by early successional native forbs. At West Point plant community composition was affected by introduced earthworm density but not deer exclusion. Native plant cover increased and non-native plant cover decreased in fenced plots, thus keeping overall plant cover similar. At both sites native forb cover increased in response to deer reduction, but the anticipated response of understory vegetation failed to materialize at the community level. Deer-favoured forbs ( Eurybia divaricata , Maianthemum racemosum , Polygonatum pubescens and Trillium recurvatum ) grew taller and flowering probability increased in the absence of deer. Plant community monitoring fails to capture

Habitat Heterogeneity Affects Plant and Arthropod Species Diversity and Turnover in Traditional Cornfields.

Directory of Open Access Journals (Sweden)

Eliana Martínez

Full Text Available The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity.

Assessment of plant species diversity based on hyperspectral indices at a fine scale.

Science.gov (United States)

Peng, Yu; Fan, Min; Song, Jingyi; Cui, Tiantian; Li, Rui

2018-03-19

Fast and nondestructive approaches of measuring plant species diversity have been a subject of excessive scientific curiosity and disquiet to environmentalists and field ecologists worldwide. In this study, we measured the hyperspectral reflectances and plant species diversity indices at a fine scale (0.8 meter) in central Hunshandak Sandland of Inner Mongolia, China. The first-order derivative value (FD) at each waveband and 37 hyperspectral indices were used to assess plant species diversity. Results demonstrated that the stepwise linear regression of FD can accurately estimate the Simpson (R 2  = 0.83), Pielou (R 2  = 0.87) and Shannon-Wiener index (R 2  = 0.88). Stepwise linear regression of FD (R 2  = 0.81, R 2  = 0.82) and spectral vegetation indices (R 2  = 0.51, R 2  = 0.58) significantly predicted the Margalef and Gleason index. It was proposed that the Simpson, Pielou and Shannon-Wiener indices, which are widely used as plant species diversity indicators, can be precisely estimated through hyperspectral indices at a fine scale. This research promotes the development of methods for assessment of plant diversity using hyperspectral data.

INAA of microelements in plant species from the Danube floodplain

Energy Technology Data Exchange (ETDEWEB)

Pantelica, A; Salagean, M; Scarlat, A [Department of Applie Physics, Horia Hulubei National Institute for Physics and Nuclear Engineering, PO Box MG-6, RO-76900 Magurele-Bucharest (Romania); Iordache, V [Department of Ecology, University of Bucharest, Bucharest (Romania)

1999-07-01

A research was developed and implemented in the Danube floodplain, as a part of a program dealing with biogeochemistry of metals, to assess the possibility of using the ubiquitous plant species in the soil pollution monitoring activity. The Danube River is heavily polluted by the input from a catchment, which includes 12 countries. Even if the concentrations in the Danube water and sediments reach acute values only in some hot spots, due to the dilution effect, they could have negative consequences by phenomena of bioaccumulation and bioconcentration. The content of Al, Ag, As, Au, Ba, Br, Ca, Cl, Ce, Co, Cr, Cs, Cu, Eu, Fe, Hg, Hf, K, La, Mg, Mn, Na, Ni, Rb, Sc, Se, Sm, Sr, Th, V and Zn in Bidens tripartita, Rubus caesius, Stachys palustris and Xanthium strumarium ubiquitous plant species, collected from two areas located on different regularly flooded islands of the Danube river was investigated by instrumental neutron activation analysis method at WWR-S reactor in Bucharest. From the statistical point of view, three groups of elements present highly correlated concentrations in the investigated plant samples (p(0.05))//. The first one includes Al, As, Ce, Cs, Eu, Fe, Hf, La, Sc, Sm, Th and V, the second one Au, Ca, Cu and Sr, and the third one Br, Cr, Na and Mn. For the elements of the first group, the elemental concentrations are found to be in similar ratios in the species investigated, namely: Xanthium s. < Rubus c. < Bidens t. < Stachys p. as well as for the third group: Bidens t. < Rubus c. < Stachys p. < Xanthium s, suggesting that physiological features of the species could be responsible for the observed patterns of distribution. The soil and dominating plant species were analysed for Cr, Cu, Fe, Mn, Ni, Pb, Zn and Zr by the X-ray fluorescence method at the Institute for Geological Explorations, Bucharest. The elemental content in soil is reflected in the analysed plants for Cr, Cu, Fe, Ni, Pb and Zn, but not for Mn. This could be explained by the redox

INAA of microelements in plant species from the Danube floodplain

International Nuclear Information System (INIS)

Pantelica, A.; Salagean, M.; Scarlat, A.; Iordache, V.

1999-01-01

A research was developed and implemented in the Danube floodplain, as a part of a program dealing with biogeochemistry of metals, to assess the possibility of using the ubiquitous plant species in the soil pollution monitoring activity. The Danube River is heavily polluted by the input from a catchment, which includes 12 countries. Even if the concentrations in the Danube water and sediments reach acute values only in some hot spots, due to the dilution effect, they could have negative consequences by phenomena of bioaccumulation and bioconcentration. The content of Al, Ag, As, Au, Ba, Br, Ca, Cl, Ce, Co, Cr, Cs, Cu, Eu, Fe, Hg, Hf, K, La, Mg, Mn, Na, Ni, Rb, Sc, Se, Sm, Sr, Th, V and Zn in Bidens tripartita, Rubus caesius, Stachys palustris and Xanthium strumarium ubiquitous plant species, collected from two areas located on different regularly flooded islands of the Danube river was investigated by instrumental neutron activation analysis method at WWR-S reactor in Bucharest. From the statistical point of view, three groups of elements present highly correlated concentrations in the investigated plant samples (p(0.05))//. The first one includes Al, As, Ce, Cs, Eu, Fe, Hf, La, Sc, Sm, Th and V, the second one Au, Ca, Cu and Sr, and the third one Br, Cr, Na and Mn. For the elements of the first group, the elemental concentrations are found to be in similar ratios in the species investigated, namely: Xanthium s. < Rubus c. < Bidens t. < Stachys p. as well as for the third group: Bidens t. < Rubus c. < Stachys p. < Xanthium s, suggesting that physiological features of the species could be responsible for the observed patterns of distribution. The soil and dominating plant species were analysed for Cr, Cu, Fe, Mn, Ni, Pb, Zn and Zr by the X-ray fluorescence method at the Institute for Geological Explorations, Bucharest. The elemental content in soil is reflected in the analysed plants for Cr, Cu, Fe, Ni, Pb and Zn, but not for Mn. This could be explained by the redox

Differential responses of soil bacteria, fungi, archaea and protists to plant species richness and plant functional group identity

NARCIS (Netherlands)

Dassen, S.; Cortois, R.; Martens, Henk; De Hollander, M.; Kowalchuk, G.A.; van der Putten, W.H.; De Deyn, G.B.

2017-01-01

Plants are known to influence belowground microbial community structure along their roots, but the impacts of plant species richness and plant functional group (FG) identity on microbial communities in the bulk soil are still not well understood. Here, we used 454-pyrosequencing to analyse the soil

Presence of indicator plant species as a predictor of wetland vegetation integrity

Science.gov (United States)

Stapanian, Martin A.; Adams, Jean V.; Gara, Brian

2013-01-01

We fit regression and classification tree models to vegetation data collected from Ohio (USA) wetlands to determine (1) which species best predict Ohio vegetation index of biotic integrity (OVIBI) score and (2) which species best predict high-quality wetlands (OVIBI score >75). The simplest regression tree model predicted OVIBI score based on the occurrence of three plant species: skunk-cabbage (Symplocarpus foetidus), cinnamon fern (Osmunda cinnamomea), and swamp rose (Rosa palustris). The lowest OVIBI scores were best predicted by the absence of the selected plant species rather than by the presence of other species. The simplest classification tree model predicted high-quality wetlands based on the occurrence of two plant species: skunk-cabbage and marsh-fern (Thelypteris palustris). The overall misclassification rate from this tree was 13 %. Again, low-quality wetlands were better predicted than high-quality wetlands by the absence of selected species rather than the presence of other species using the classification tree model. Our results suggest that a species’ wetland status classification and coefficient of conservatism are of little use in predicting wetland quality. A simple, statistically derived species checklist such as the one created in this study could be used by field biologists to quickly and efficiently identify wetland sites likely to be regulated as high-quality, and requiring more intensive field assessments. Alternatively, it can be used for advanced determinations of low-quality wetlands. Agencies can save considerable money by screening wetlands for the presence/absence of such “indicator” species before issuing permits.

Plant species richness and abundance in residential yards across a tropical watershed: implications for urban sustainability

Directory of Open Access Journals (Sweden)

Cristina P. Vila-Ruiz

2014-09-01

Full Text Available Green spaces within residential areas provide important contributions to the sustainability of urban systems. Therefore, studying the characteristics of these areas has become a research priority in cities worldwide. This project evaluated various aspects of the plant biodiversity of residential yards (i.e., front yards and back yards within the Río Piedras watershed in the San Juan metropolitan area of Puerto Rico. Our work included gathering information on vegetation composition and abundance of woody species (i.e., trees, shrubs, palms, ferns and large herbs (>2 m height, species origin (native vs. introduced, and species uses (ornamental, food, and medicinal plants. A total of 424 yards were surveyed within an area of 187,191 m². We found 383 woody species, with shrubs being the most abundant plant habitat. As expected, residential yards hosted a disproportionate amount of introduced species (69.5%. The most common shrub species were all non-native ornamentals, whereas the most common tree species included food trees as well as ornamental plants and two native species. Front yards hosted more ornamental species per unit area than backyards, while the latter had more food plants. The high amount of introduced species may present a challenge in terms of implementation of plant conservation initiatives if there is no clear definition of urban conservation goals. On the other hand, the high frequency of yards containing food plants may facilitate the development of residential initiatives that could provide future adaptive capacity to food shortages.

Nest site selection and breeding success in three Turdus thrush species coexisting in an urban environment

Czech Academy of Sciences Publication Activity Database

Mikula, P.; Hromada, M.; Albrecht, Tomáš; Tryjanowski, P.

2014-01-01

Roč. 49, č. 1 (2014), s. 83-92 ISSN 0001-6454 Institutional support: RVO:68081766 Keywords : breeding success * coexistence * nest-habitat partitioning * nest site selection * predation * synurbization * urban habitat * thrushes Subject RIV: EG - Zoology Impact factor: 0.745, year: 2014

Arsenic speciation in moso bamboo shoot - A terrestrial plant that contains organoarsenic species

Energy Technology Data Exchange (ETDEWEB)

Zhao Rui [Department of Chemistry, Key laboratory for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua University, Beijing 100084, P.R. China (China); Zhao Mengxia [Department of Chemistry, Key laboratory for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua University, Beijing 100084 (China); Wang Hui [Department of Chemistry, Key laboratory for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua University, Beijing 100084 (China); Taneike, Yasuhito [Shimadzu Co Ltd, Spectroscopy Business Unit Analytical Instruments Div, Nakagyo Ku, Kyoto, 6048511 (Japan); Zhang Xinrong [Department of Chemistry, Key laboratory for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua University, Beijing 100084 (China)]. E-mail: xrzhang@chem.tsinghua.edu.cn

2006-12-01

Arsenic is predominantly found as an inorganic species in most terrestrial plants. However, we found that a significant proportion of organic arsenic was present in moso bamboo (Phyllostachys pubescens Mazel) shoot in a market survey of arsenic species in edible terrestrial plants. Moso bamboo shoots from different producing areas in China were collected for analysis to confirm the ubiquity of methylated arsenic species. The total arsenic concentrations of bamboo shoots were determined by hydride generation coupled atomic fluorescence spectrometry (HG-AFS), ranging from 27.7 to 94.0 {mu}g/kg. Information about arsenic species was acquired from cold trap-hydride generation-atomic absorption spectrometry (CT-HG-AAS). Dimethylarsinic acid (DMA) was present in the amount of 13.9% to 44.9% of sum of the arsenic species in all these samples. Monomethylarsonic acid (MMA) and trimethylarsine oxide (TMAO) were also detected in certain samples in the range of 4.2-16.5% and 11.8-18.4%, respectively. In addition, bamboo shoots collected in winter were found to have more total arsenic and organic arsenic than those collected in spring. To investigate the source of the organic arsenic in moso bamboo shoots, arsenic species in the rhizosphere soils of the plants were examined. The absence of organic arsenic in soils would suggest the possibility of formation of methylated arsenic in the plants. In addition, studies of arsenic speciation in the peel and core of winter bamboo shoots showed that all the cores contained organic arsenic while no organic arsenic was detected in the peels. The study provides useful information for better understanding of the distribution of arsenic species in terrestrial plants.

Plant and animal species composition and heavy metal content in fly ash ecosystems

International Nuclear Information System (INIS)

Brieger, G.; Wells, J.R.; Hunter, R.D.

1992-01-01

Plant and animal species present on a coal fly ash slurry pond site and a dry deposit site were surveyed and sampled during a two-day period in October. Elemental analyses were determined for most of the species encountered. A total of 48 plant species were observed on the two sites, with 35 species on the wet site, and 20 on the dry site. Eighteen terrestrial and 7 aquatic animal species were found on the wet site, exclusive of vertebrates which were not studied with the exception of a carp (Cyprinus carpio). Eleven terrestrial invertebrate and one aquatic species were observed on the dry site. Neutron activation analysis was carried out for: Se, Hg, Cr, Ni, Zn, Co, Sb, Cd, and As. Using literature values for phytotoxicity, it is concluded that, in general, plants did not accumulate toxic levels of metals. Only one plant (Impatiens biflora Willd.) showed a significant level of Cd. Of 20 plants analyzed on the wet site, 10 had excessive Se concentrations (>5 ppm); on the dry site 6 out of 18 had high Se values. In animals (Gryllus sp.; Melanoplus sp.; Trachelipus sp; Lumbricus terrestris; Physa integra; Cyprinus carpio) the trace metal concentration was generally in between that of control animals and that of the fly ash itself. One exception included Zn, which, although the most variable element examined, was concentrated in all the terrestrial animals to levels higher than in fly ash. Crickets are the most consistent bioconcentrators with Cr, Se, and Zn at higher levels than for control animals. All animals species studied accumulated Se compared to controls. 48 refs., 6 tabs

Predicting the presence and cover of management relevant invasive plant species on protected areas.

Science.gov (United States)

Iacona, Gwenllian; Price, Franklin D; Armsworth, Paul R

2016-01-15

Invasive species are a management concern on protected areas worldwide. Conservation managers need to predict infestations of invasive plants they aim to treat if they want to plan for long term management. Many studies predict the presence of invasive species, but predictions of cover are more relevant for management. Here we examined how predictors of invasive plant presence and cover differ across species that vary in their management priority. To do so, we used data on management effort and cover of invasive plant species on central Florida protected areas. Using a zero-inflated multiple regression framework, we showed that protected area features can predict the presence and cover of the focal species but the same features rarely explain both. There were several predictors of either presence or cover that were important across multiple species. Protected areas with three days of frost per year or fewer were more likely to have occurrences of four of the six focal species. When invasive plants were present, their proportional cover was greater on small preserves for all species, and varied with surrounding household density for three species. None of the predictive features were clearly related to whether species were prioritized for management or not. Our results suggest that predictors of cover and presence can differ both within and across species but do not covary with management priority. We conclude that conservation managers need to select predictors of invasion with care as species identity can determine the relationship between predictors of presence and the more management relevant predictors of cover. Copyright © 2015 Elsevier Ltd. All rights reserved.

Physiological measurements of coffee young plants coexisting with sourgrass

Directory of Open Access Journals (Sweden)

Pedro Luis da Costa Aguiar Alves

2012-03-01

Full Text Available Coffee is an important crop planted in Brazil and commonly infested by sourgrass plants. Crescent densities of sourgrass growing with coffee young plants were maintained up to weed full flowering when physiological measurements were performed in the crop to evaluate photosynthetic coffee plant responses to increasing of weed competition. Experiments were arranged in a completely randomized design with seven replicates. The concentration of CO2 within the leaf, the leaf transpiration, the stomatal conductance, the CO2 assimilation rate, and the ratio Fv/Fm of coffee plants were not affected by increasing of sourgrass density. On the other hand, relative content of total chlorophyll was reduced by 13.9% in the density of 8 sourgrass plants. Gas exchange and fluorescence of chlorophyll of young coffee plants were not dependent on increasing of the intensity of competition while an opposite response occurred for chlorophyll content.

Temporal-spatial dynamics in orthoptera in relation to nutrient availability and plant species richness.

Directory of Open Access Journals (Sweden)

Rob J J Hendriks

Full Text Available Nutrient availability in ecosystems has increased dramatically over the last century. Excess reactive nitrogen deposition is known to negatively impact plant communities, e.g. by changing species composition, biomass and vegetation structure. In contrast, little is known on how such impacts propagate to higher trophic levels. To evaluate how nitrogen deposition affects plants and herbivore communities through time, we used extensive databases of spatially explicit historical records of Dutch plant species and Orthoptera (grasshoppers and crickets, a group of animals that are particularly susceptible to changes in the C:N ratio of their resources. We use robust methods that deal with the unstandardized nature of historical databases to test whether nitrogen deposition levels and plant richness changes influence the patterns of richness change of Orthoptera, taking into account Orthoptera species functional traits. Our findings show that effects indeed also propagate to higher trophic levels. Differences in functional traits affected the temporal-spatial dynamics of assemblages of Orthoptera. While nitrogen deposition affected plant diversity, contrary to our expectations, we could not find a strong significant effect of food related traits. However we found that species with low habitat specificity, limited dispersal capacity and egg deposition in the soil were more negativly affected by nitrogen deposition levels. Despite the lack of significant effect of plant richness or food related traits on Orthoptera, the negative effects of nitrogen detected within certain trait groups (e.g. groups with limited disperse ability could be related to subtle changes in plant abundance and plant quality. Our results, however, suggest that the changes in soil conditions (where many Orthoptera species lay their eggs or other habitat changes driven by nitrogen have a stronger influence than food related traits. To fully evaluate the negative effects of nitrogen

Uptake of inorganic phosphorus by the aquatic plant Isoetes australis inhabiting oligotrophic vernal rock pools

DEFF Research Database (Denmark)

Christiansen, Nina Høj; Pulido, Cristina; Pedersen, Ole

2017-01-01

The submerged aquatic freshwater macrophyte Isoetes australis S. Williams grows in rock pools situated in south-western Australia, an environment where dissolved inorganic phosphorus (Pi) availability possibly limits growth. In contrast to the two coexisting aquatic species, Glossostigma drummundii...... experiment revealed high amounts of Pi translocation internally in the plant which seemed to go from roots and oldest leaves to younger leaves. As a result of the high root to shoot ratio, high surface area, root uptake kinetics, and sediment Pi availability, roots accounted for 87% of plant Pi uptake...

Coexistence facilitates interspecific biofilm formation in complex microbial communities

DEFF Research Database (Denmark)

Madsen, Jonas Stenløkke; Røder, Henriette Lyng; Russel, Jakob

2016-01-01

Social interactions in which bacteria respond to one another by modifying their phenotype are central determinants of microbial communities. It is known that interspecific interactions influence the biofilm phenotype of bacteria; a phenotype that is central to the fitness of bacteria. However......, the underlying role of fundamental ecological factors, specifically coexistence and phylogenetic history, in biofilm formation remains unclear. This study examines how social interactions affect biofilm formation in multi-species co-cultures from five diverse environments. We found prevalence of increased...

Floristic characteristics of alien invasive seed plant species in China.

Science.gov (United States)

Wang, Congyan; Liu, Jun; Xiao, Hongguang; Zhou, Jiawei; DU, Daolin

2016-01-01

This study aims to determine the floristic characteristics of alien invasive seed plant species (AISPS) in China. There are a total of five hundred and thirteen AISPS, belonging to seventy families and two hundred and eighty-three genera. Seventy families were classified into nine areal types at the family level, and "Cosmopolitan" and "Pantropic" are the two main types. Two hundred and eighty-three genera were classified into twelve areal types at the genus level, and "Pantropic", "Trop. Asia & Amer. disjuncted", and "Cosmopolitan" are the three main types. These results reveal a certain degree of diversity among AISPS in China. The floristic characteristics at the family level exhibit strong pantropic characteristics. Two possible reasons for this are as follows. Firstly, southeastern China is heavily invaded by alien invasive plant species and this region has a mild climate. Secondly, southeastern China is more disturbed by human activities than other regions in China. The floristic characteristics at the genus level display strong pantropic but with abundant temperate characteristics. This may be due to that China across five climatic zones and the ecosystems in which the most alien invasive plant species occur have the same or similar climate with their natural habitat.

Host Plant Species Differentiation in a Polyphagous Moth: Olfaction is Enough.

Science.gov (United States)

Conchou, Lucie; Anderson, Peter; Birgersson, Göran

2017-08-01

Polyphagous herbivorous insects need to discriminate suitable from unsuitable host plants in complex plant communities. While studies on the olfactory system of monophagous herbivores have revealed close adaptations to their host plant's characteristic volatiles, such adaptive fine-tuning is not possible when a large diversity of plants is suitable. Instead, the available literature on polyphagous herbivore preferences suggests a higher level of plasticity, and a bias towards previously experienced plant species. It is therefore necessary to take into account the diversity of plant odors that polyphagous herbivores encounter in the wild in order to unravel the olfactory basis of their host plant choice behaviour. In this study we show that a polyphagous moth, Spodoptera littoralis, has the sensory ability to distinguish five host plant species using olfaction alone, this being a prerequisite to the ability to make a choice. We have used gas chromatography mass spectrometry (GC-MS) and gas chromatography electroantennographic detection (GC-EAD) in order to describe host plant odor profiles as perceived by S. littoralis. We find that each plant emits specific combinations and proportions of GC-EAD active volatiles, leading to statistically distinct profiles. In addition, at least four of these plants show GC-EAD active compound proportions that are conserved across individual plants, a characteristic that enables insects to act upon previous olfactory experiences during host plant choice. By identifying the volatiles involved in olfactory differentiation of alternative host plants by Spodoptera littoralis, we set the groundwork for deeper investigations of how olfactory perceptions translate into behaviour in polyphagous herbivores.

Plant-Associated Symbiotic Burkholderia Species Lack Hallmark Strategies Required in Mammalian Pathogenesis

Science.gov (United States)

Fong, Stephanie; Yerrapragada, Shailaja; Estrada-de los Santos, Paulina; Yang, Paul; Song, Nannie; Kano, Stephanie; de Faria, Sergio M.; Dakora, Felix D.; Weinstock, George; Hirsch, Ann M.

2014-01-01

Burkholderia is a diverse and dynamic genus, containing pathogenic species as well as species that form complex interactions with plants. Pathogenic strains, such as B. pseudomallei and B. mallei, can cause serious disease in mammals, while other Burkholderia strains are opportunistic pathogens, infecting humans or animals with a compromised immune system. Although some of the opportunistic Burkholderia pathogens are known to promote plant growth and even fix nitrogen, the risk of infection to infants, the elderly, and people who are immunocompromised has not only resulted in a restriction on their use, but has also limited the application of non-pathogenic, symbiotic species, several of which nodulate legume roots or have positive effects on plant growth. However, recent phylogenetic analyses have demonstrated that Burkholderia species separate into distinct lineages, suggesting the possibility for safe use of certain symbiotic species in agricultural contexts. A number of environmental strains that promote plant growth or degrade xenobiotics are also included in the symbiotic lineage. Many of these species have the potential to enhance agriculture in areas where fertilizers are not readily available and may serve in the future as inocula for crops growing in soils impacted by climate change. Here we address the pathogenic potential of several of the symbiotic Burkholderia strains using bioinformatics and functional tests. A series of infection experiments using Caenorhabditis elegans and HeLa cells, as well as genomic characterization of pathogenic loci, show that the risk of opportunistic infection by symbiotic strains such as B. tuberum is extremely low. PMID:24416172

Are plant species able to keep pace with the rapidly changing climate?

Directory of Open Access Journals (Sweden)

Sarah Cunze

Full Text Available Future climate change is predicted to advance faster than the postglacial warming. Migration may therefore become a key driver for future development of biodiversity and ecosystem functioning. For 140 European plant species we computed past range shifts since the last glacial maximum and future range shifts for a variety of Intergovernmental Panel on Climate Change (IPCC scenarios and global circulation models (GCMs. Range shift rates were estimated by means of species distribution modelling (SDM. With process-based seed dispersal models we estimated species-specific migration rates for 27 dispersal modes addressing dispersal by wind (anemochory for different wind conditions, as well as dispersal by mammals (dispersal on animal's coat - epizoochory and dispersal by animals after feeding and digestion - endozoochory considering different animal species. Our process-based modelled migration rates generally exceeded the postglacial range shift rates indicating that the process-based models we used are capable of predicting migration rates that are in accordance with realized past migration. For most of the considered species, the modelled migration rates were considerably lower than the expected future climate change induced range shift rates. This implies that most plant species will not entirely be able to follow future climate-change-induced range shifts due to dispersal limitation. Animals with large day- and home-ranges are highly important for achieving high migration rates for many plant species, whereas anemochory is relevant for only few species.

Invasive vascular plant species of limnocrenic karst springs in Poland

Science.gov (United States)

Spałek, Krzysztof

2015-04-01

Natural water reservoirs are very valuable floristic sites in Poland. Among them, the most important for preservation of biodiversity of flora are limnocrenic karst springs. The long-term process of human pressure on habitats of this type caused disturbance of their biological balance. Changes in the water regime, industrial development and chemisation of agriculture, especially in the period of last two hundred years, led to systematic disappearance of localities of many plant species connected with rare habitats and also to appear numerous invasive plant species. They are: Acorus calamus, Echinocystis lobata, Elodea canadensis, Erechtites hieraciifolia, Impatiens glandulifera, Solidago canadensis, S. gigantea and S. graminifolia. Fielworks were conducted in 2010-2014.

Multi-scale habitat modification by coexisting ecosystem engineers drives spatial separation of macrobenthic functional groups

NARCIS (Netherlands)

Donadi, S.; van der Heide, T.; Piersma, T.; van der Zee, E.M.; Weerman, E.J.; van de Koppel, J.; Olff, H.; Devine, C.; Hernawan, U. E.; Boers, M.; Planthof, L.; Eriksson, B.K.

2015-01-01

By changing habitat conditions, ecosystem engineers increase niche diversity and have profound effects on the distribution and abundances of other organisms. Although many ecosystems contain several engineering species, it is still unclear how the coexistence of multiple engineers affects the

Ecology of the coexisting copepod species in Cochin backwaters

Digital Repository Service at National Institute of Oceanography (India)

Madhupratap, M.

of the high saline species. The degree of ecological differentiation between them was not very clear. Probably the peculiarities of the estuarine system allowed them to survive as competitors, since it is conceivable that the competing species expand...

Patterns of species diversity and phylogenetic structure of vascular plants on the Qinghai-Tibetan Plateau.

Science.gov (United States)

Yan, Yujing; Yang, Xian; Tang, Zhiyao

2013-11-01

Large-scale patterns of species richness and the underlying mechanisms regulating these patterns have long been the central issues in biogeography and macroecology. Phylogenetic community structure is a result of combined effects of contemporary ecological interactions, environmental filtering, and evolutionary history, and it links community ecology with biogeography and trait evolution. The Qinghai-Tibetan Plateau provides a good opportunity to test the influence of contemporary climate on shaping species richness because of its unique geological history, cold climate, and high biodiversity. In this study, based on high-resolution distributions of ˜9000 vascular plant species, we explored how species richness and phylogenetic structure of vascular plants correlate with climates on the highest (and species rich) plateau on the Earth. The results showed that most of the vascular plants were distributed on the eastern part of the plateau; there was a strong association between species richness and climate, even after the effects of habitat heterogeneity were controlled. However, the responses of richness to climate remarkably depended on life-forms. Richness of woody plants showed stronger climatic associations than that of herbaceous plants; energy and water availability together regulated richness pattern of woody plants; whereas water availability predominantly regulated richness pattern of herbaceous plants. The phylogenetic structure of vascular species clustered in most areas of the plateau, suggesting that rapid speciation and environment filtering dominated the assembly of communities on the plateau. We further propose that biodiversity conservation in this area should better take into account ecological features for different life-forms and phylogenetic lineages.

Are the metabolomic responses to folivory of closely related plant species linked to macroevolutionary and plant-folivore coevolutionary processes?

Energy Technology Data Exchange (ETDEWEB)

Rivas-Ubach, Albert [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington 99354 USA; CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; Hódar, José A. [Grupo de Ecología Terrestre, Departamento de Biología Animal y Ecología, Facultad de Ciencias, Universidad de Granada, 18071 Granada Spain; Sardans, Jordi [CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; CSIC, Global Ecology Unit CREAF-CEAB-CSIC-UAB, Cerdanyola del Vallès 08913 Catalonia Spain; Kyle, Jennifer E. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland Washington 99354 USA; Kim, Young-Mo [Biological Sciences Division, Pacific Northwest National Laboratory, Richland Washington 99354 USA; Oravec, Michal [Global Change Research Centre, Academy of Sciences of the Czech Republic, Bĕlidla 4a CZ-603 00 Brno Czech Republic; Urban, Otmar [Global Change Research Centre, Academy of Sciences of the Czech Republic, Bĕlidla 4a CZ-603 00 Brno Czech Republic; Guenther, Alex [Department of Earth System Science, University of California, Irvine California 92697 USA; Peñuelas, Josep [CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; CSIC, Global Ecology Unit CREAF-CEAB-CSIC-UAB, Cerdanyola del Vallès 08913 Catalonia Spain

2016-06-02

The debate whether the coevolution of plants and insects or macroevolutionary processes (phylogeny) is the main driver determining the arsenal of molecular defensive compounds of plants remains unresolved. Attacks by herbivorous insects affect not only the composition of defensive compounds in plants but the entire metabolome (the set of molecular metabolites), including defensive compounds. Metabolomes are the final products of genotypes and are directly affected by macroevolutionary processes, so closely related species should have similar metabolomic compositions and may respond in similar ways to attacks by folivores. We analyzed the elemental compositions and metabolomes of needles from Pinus pinaster, P. nigra and P. sylvestris to determine if these closely related Pinus species with different coevolutionary histories with the caterpillars of the processionary moth respond similarly to attacks by this lepidopteran. All pines had different metabolomes and metabolic responses to herbivorous attack. The metabolomic variation among the pine species and the responses to folivory reflected their macroevolutionary relationships, with P. pinaster having the most divergent metabolome. The concentrations of phenolic metabolites were generally not higher in the attacked trees, which had lower concentrations of terpenes, suggesting that herbivores avoid individuals with high concentrations of terpenes. Our results suggest that macroevolutionary history plays important roles in the metabolomic responses of these pine species to folivory, but plant-insect coevolution probably constrains those responses. Combinations of different evolutionary factors and trade-offs are likely responsible for the different responses of each species to folivory, which is not necessarily exclusively linked to plant-insect coevolution.

Shape coexistence in selenium isotopes

International Nuclear Information System (INIS)

Liu Ying; Cao Zhongbin; Xu Furong

2010-01-01

Nuclear shape change and shape coexistence in the Selenium isotopes have been investigated by Total-Routhian-Surface (TRS) calculations. It is found that nuclear shapes vary significantly with increasing neutron number. The TRS calculations for the ground states of 66,72,92,94 Se isotopes show that both neutron-deficient and neutron-dripline Selenium isotopes have oblate and prolate shape coexistence. The cranking shell-model calculations for 72,94 Se give that prolate and oblate shape coexistence in low rotational frequency. However, oblate rotational bands disappear and prolate rotational bands become yrast bands with increasing rotational frequency, which is due to the intrusion of the g 9/2 orbitals. (authors)

Alien roadside species more easily invade alpine than lowland plant communities in a subarctic mountain ecosystem.

Directory of Open Access Journals (Sweden)

Jonas J Lembrechts

Full Text Available Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment.

Alien roadside species more easily invade alpine than lowland plant communities in a subarctic mountain ecosystem.

Science.gov (United States)

Lembrechts, Jonas J; Milbau, Ann; Nijs, Ivan

2014-01-01

Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment.

Biological invasions: economic and environmental costs of alien plant, animal, and microbe species

National Research Council Canada - National Science Library

Pimentel, David

2011-01-01

...: Economic and Environmental Costs of Alien Plant, Animal, and Microbe Species, this reference discusses how non-native species invade new ecosystems and the subsequent economic and environmental effects of these species...

Coexistence of reef organisms in the Abrolhos Archipelago, Brazil

Directory of Open Access Journals (Sweden)

Monica M Lins de Barros

2000-12-01

Full Text Available The first study on coexistence of reef benthic organisms in Brazilian coral reefs was done in three localities of the Abrolhos Archipelago. Organisms were recorded in concentric circle samples (10 and 20 cm in diameter randomly laid on transects. Type and frequency of "coexistence events" between pairs of organisms were determined. Most frequent organisms (massive and branched coralline algae, Favia gravida, and Agaricia agaricites also had many significant positive coexistence events. These results might be related to the abundances of these organisms. The most frequent coral (Siderastrea stellata, however, exhibited only a few significant coexistence events (9% of 32 tests. Since the great majority of events were positive, and since there was high variation in the species/groups involved in significant events in different localities, benthic communities of Abrolhos Archipelago may well be structured primarily by abiotic rather than biotic factors.Se hizo el primer estudio de coexistencia de organismos bénticos de arrecifes brasileños en tres localidades del Archipiélago de Abrolhos, registrando la presencia de organismos en círculos de 10 y 20 cm de diametro, distribuidos al azar en transectos. La mayoría de los organismo frecuentes (algas coralinas macizas y ramificadas, Favia gravida y Agaricia agaricites mostraron la más alta "coexistencia positiva", tal vez por su abundancia. El coral más frecuente (Siderastrea stellata, sin embargo, mostró apenas algunos eventos de coexistencia significativos (9% de 32 ensayos. Debido a que la mayor parte de los eventos fue positiva, y considerando que existe una alta variabilidad en las interacciones significativas en diferentes localidades, las comunidades bénticas del Archipiélago de Abrolhos pueden haber sido estructuradas principalmente por factores abióticos, mas que por factores bióticos.

The role of plant-soil feedbacks in driving native-species recovery.

Science.gov (United States)

Yelenik, Stephanie G; Levine, Jonathan M

2011-01-01

The impacts of exotic plants on soil nutrient cycling are often hypothesized to reinforce their dominance, but this mechanism is rarely tested, especially in relation to other ecological factors. In this manuscript we evaluate the influence of biogeochemically mediated plant-soil feedbacks on native shrub recovery in an invaded island ecosystem. The introduction of exotic grasses and grazing to Santa Cruz Island, California, USA, converted native shrublands (dominated by Artemisia californica and Eriogonum arborescens) into exotic-dominated grasslands (dominated by Avena barbata) over a century ago, altering nutrient-cycling regimes. To test the hypothesis that exotic grass impacts on soils alter reestablishment of native plants, we implemented a field-based soil transplant experiment in three years that varied widely in rainfall. Our results showed that growth of Avena and Artemisia seedlings was greater on soils influenced by their heterospecific competitor. Theory suggests that the resulting plant-soil feedback should facilitate the recovery of Artemisia in grasslands, although four years of monitoring showed no such recovery, despite ample seed rain. By contrast, we found that species effects on soils lead to weak to negligible feedbacks for Eriogonum arborescens, yet this shrub readily colonized the grasslands. Thus, plant-soil feedbacks quantified under natural climate and competitive conditions did not match native-plant recovery patterns. We also found that feedbacks changed with climate and competition regimes, and that these latter factors generally had stronger effects on seedling growth than species effects on soils. We conclude that even when plant-soil feedbacks influence the balance between native and exotic species, their influence may be small relative to other ecological processes.

Phytoaccumulation of trace elements by wetland plants: 3. Uptake and accumulation of ten trace elements by twelve plant species

Energy Technology Data Exchange (ETDEWEB)

Qian, J.H.; Zayed, A.; Zhu, Y.L.; Yu, M.; Terry, N.

1999-10-01

Interest is increasing in using wetland plants in constructed wetlands to remove toxic elements from polluted wastewater. To identify those wetland plants that hyperaccumulate trace elements, 12 plant species were tested for their efficiency to bioconcentrate 10 potentially toxic trace elements including As, b, Cd, Cr, Cu, Pb, Mn, Hg, Ni, and Se. Individual plants were grown under carefully controlled conditions and supplied with 1 mg L{sup {minus}1} of each trace element individually for 10 d. Except B, all elements accumulated to much higher concentrations in roots than in shoots. Highest shoot tissue concentrations (mg kg{sup {minus}1} DW) of the various trace elements were attained by the following species: umbrella plant (Cyperus alternifolius L.) for Mn (198) and Cr (44); water zinnia (Wedelia trilobata Hitchc.) for Cd (148) and Ni (80); smartweed (Polygonum hydropiperoides Michx.) for Cu (95) and Pb (64); water lettuce (Pistia stratiotes L.) for Hg (92), As (34), and Se (39); and mare's tail (hippuris vulgaris L.) for B (1132). Whereas, the following species attained the highest root tissue concentrations (mg kg{sup {minus}1} DW); stripped rush (Baumia rubiginosa) for Mn (1683); parrot's feather (Myriophyllum brasiliense Camb.) for Cd (1426) and Ni (1077); water lettuce for Cu (1038), Hg (1217), and As (177); smartweed for Cr (2980) and Pb (1882); mare's tail for B (1277); and monkey flower (Mimulus guttatus Fisch.) for Se (384). From a phytoremediation perspective, smartweed was probably the best plant species for trace element removal from wastewater due to its faster growth and higher plant density.

Neighbourhood structure and light availability influence the variations in plant design of shrubs in two cloud forests of different successional status.

Science.gov (United States)

Guzmán Q, J Antonio; Cordero, Roberto A

2016-07-01

Plant design refers to the construction of the plant body or its constituent parts in terms of form and function. Although neighbourhood structure is recognized as a factor that limits plant survival and species coexistence, its relative importance in plant design is not well understood. We conducted field research to analyse how the surrounding environment of neighbourhood structure and related effects on light availability are associated with changes in plant design in two understorey plants (Palicourea padifolia and Psychotria elata) within two successional stages of a cloud forest in Costa Rica. Features of plant neighbourhood physical structure and light availability, estimated using hemispherical photographs, were used as variables that reflect the surrounding environment. Measures of plant biomechanics, allometry, branching and plant slenderness were used as functional plant attributes that reflect plant design. We propose a framework using a partial least squares path model and used it to test this association. The multidimensional response of plant design of these species suggests that decreases in the height-based factor of safety and increases in mechanical load and developmental stability are influenced by increases in maximum height of neighbours and a distance-dependence interference index more than neighbourhood plant density or neighbour aggregation. Changes in plant branching and slenderness are associated positively with light availability and negatively with canopy cover. Although it has been proposed that plant design varies according to plant density and light availability, we found that neighbour size and distance-dependence interference are associated with changes in biomechanics, allometry and branching, and they must be considered as key factors that contribute to the adaptation and coexistence of these plants in this highly diverse forest community. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany

A comparative study of AMF diversity in annual and perennial plant species from semiarid gypsum soils.

Science.gov (United States)

Alguacil, M. M.; Torrecillas, E.; Roldán, A.; Díaz, G.; Torres, P.

2012-04-01

The arbuscular mycorrhizal fungi (AMF) communities composition regulate plant interactions and determine the structure of plant communities. In this study we analysed the diversity of AMF in the roots of two perennial gypsophyte plant species, Herniaria fruticosa and Senecio auricula, and an annual herbaceous species, Bromus rubens, growing in a gypsum soil from a semiarid area. The objective was to determine whether perennial and annual host plants support different AMF communities in their roots and whether there are AMF species that might be indicators of specific functional plant roles in these ecosystems. The roots were analysed by nested PCR, cloning, sequencing of the ribosomal DNA small subunit region and phylogenetic analysis. Twenty AMF sequence types, belonging to the Glomus group A, Glomus group B, Diversisporaceae, Acaulosporaceae, Archaeosporaceae and Paraglomeraceae, were identified. Both gypsophyte perennial species had differing compositions of the AMF community and higher diversity when compared with the annual species, showing preferential selection by specific AMF sequences types. B. rubens did not show host specificity, sharing the full composition of its AMF community with both perennial plant species. Seasonal variations in the competitiveness of AM fungi could explain the observed differences in AMF community composition, but this is still a working hypothesis that requires the analysis of further data obtained from a higher number of both annual and perennial plant species in order to be fully tested.

Distribution of the invasive plant species Heracleum sosnowskyi Manden. in the Komi Republic (Russia).

Science.gov (United States)

Chadin, Ivan; Dalke, Igor; Zakhozhiy, Ilya; Malyshev, Ruslan; Madi, Elena; Olga Kuzivanova; Kirillov, Dmitrii; Elsakov, Vladimir

2017-01-01

Occurrences of the invasive plant species Heracleum sosnowskyi Manden. in the Komi Republic (northeastern part of European Russia) were recorded and published in the Global Biodiversity Information Facility (GBIF http://www.gbif.org) using the RIVR information system (http://ib.komisc.ru/add/rivr/en). RIVR stands for "Rasprostranenie Invasionnyh Vidov Rastenij" [Occurrence of Invasion Plant Species]. This citizen science project aims at collecting occurrence data about invasive plant species with the help of citizen scientists. Information can be added by any user after a simple registration (concept) process. However, the data published in GBIF are provided only by professional scientists. The total study area is approximately 19,000 km 2 . The GBIF resource contains 10894 Heracleum sosnowskyi occurrence points, each with their geographical coordinates and photographs of the plants in the locus of growth. The preliminary results of species distribution modelling on the territory of European North-East Russia presented.

Differences in growth trajectory and strategy of two sympatric congeneric species in an Indonesian floodplain forest.

Science.gov (United States)