The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Wayne Dawson - One of the best experts on this subject based on the ideXlab platform.
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commonness and rarity of alien and native plant species the relative roles of Intraspecific Competition and plant soil feedback
Oikos, 2016Co-Authors: Gregor Muller, Mark Van Kleunen, Wayne DawsonAbstract:The success of invasive alien and common native species may be explained by the same underlying mechanisms. Differences in Intraspecific Competition as well as differences in plant–soil feedback have been put forward as potential determinants of plant success. We teased apart the relative roles of Competition and plant–soil feedback in a greenhouse experiment with 30 common and rare alien and native species from nine plant families. We tested whether plant biomass decreased less for common than rare species, regardless of origin, when grown at higher relative frequencies (1, 3 or 6 out of 9 plants per pot) in a community and in soil previously conditioned by the same species at different frequencies (0, 1, 3 or 6 out of 9 plants per pot) in an orthogonal design for these two factors. Plant survival decreased slightly, but non-significantly, for all species when grown in soil previously occupied by conspecifics. Among surviving plants, we found a decrease in biomass with increasing Intraspecific Competition across all species (regardless of origin or commonness), and alien species were more negatively affected by previous high plant frequency than native species, but only marginally significantly so. Our findings suggest that, while Intraspecific Competition limits individual biomass in a density-dependent manner, these effects do not depend on species origin or commonness. Notably, alien species but not natives showed a decrease in performance when grown in soil pre-conditioned with a higher frequency of conspecifics. In conclusion, soil-borne pathogen accumulation might be weak in its effects on plant performance compared to Intraspecific Competition, with neither being clearly linked to species commonness.
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Commonness and rarity of alien and native plant species – the relative roles of Intraspecific Competition and plant–soil feedback
Oikos, 2016Co-Authors: Gregor Muller, Mark Van Kleunen, Wayne DawsonAbstract:The success of invasive alien and common native species may be explained by the same underlying mechanisms. Differences in Intraspecific Competition as well as differences in plant–soil feedback have been put forward as potential determinants of plant success. We teased apart the relative roles of Competition and plant–soil feedback in a greenhouse experiment with 30 common and rare alien and native species from nine plant families. We tested whether plant biomass decreased less for common than rare species, regardless of origin, when grown at higher relative frequencies (1, 3 or 6 out of 9 plants per pot) in a community and in soil previously conditioned by the same species at different frequencies (0, 1, 3 or 6 out of 9 plants per pot) in an orthogonal design for these two factors. Plant survival decreased slightly, but non-significantly, for all species when grown in soil previously occupied by conspecifics. Among surviving plants, we found a decrease in biomass with increasing Intraspecific Competition across all species (regardless of origin or commonness), and alien species were more negatively affected by previous high plant frequency than native species, but only marginally significantly so. Our findings suggest that, while Intraspecific Competition limits individual biomass in a density-dependent manner, these effects do not depend on species origin or commonness. Notably, alien species but not natives showed a decrease in performance when grown in soil pre-conditioned with a higher frequency of conspecifics. In conclusion, soil-borne pathogen accumulation might be weak in its effects on plant performance compared to Intraspecific Competition, with neither being clearly linked to species commonness.
Mark Van Kleunen - One of the best experts on this subject based on the ideXlab platform.
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commonness and rarity of alien and native plant species the relative roles of Intraspecific Competition and plant soil feedback
Oikos, 2016Co-Authors: Gregor Muller, Mark Van Kleunen, Wayne DawsonAbstract:The success of invasive alien and common native species may be explained by the same underlying mechanisms. Differences in Intraspecific Competition as well as differences in plant–soil feedback have been put forward as potential determinants of plant success. We teased apart the relative roles of Competition and plant–soil feedback in a greenhouse experiment with 30 common and rare alien and native species from nine plant families. We tested whether plant biomass decreased less for common than rare species, regardless of origin, when grown at higher relative frequencies (1, 3 or 6 out of 9 plants per pot) in a community and in soil previously conditioned by the same species at different frequencies (0, 1, 3 or 6 out of 9 plants per pot) in an orthogonal design for these two factors. Plant survival decreased slightly, but non-significantly, for all species when grown in soil previously occupied by conspecifics. Among surviving plants, we found a decrease in biomass with increasing Intraspecific Competition across all species (regardless of origin or commonness), and alien species were more negatively affected by previous high plant frequency than native species, but only marginally significantly so. Our findings suggest that, while Intraspecific Competition limits individual biomass in a density-dependent manner, these effects do not depend on species origin or commonness. Notably, alien species but not natives showed a decrease in performance when grown in soil pre-conditioned with a higher frequency of conspecifics. In conclusion, soil-borne pathogen accumulation might be weak in its effects on plant performance compared to Intraspecific Competition, with neither being clearly linked to species commonness.
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Commonness and rarity of alien and native plant species – the relative roles of Intraspecific Competition and plant–soil feedback
Oikos, 2016Co-Authors: Gregor Muller, Mark Van Kleunen, Wayne DawsonAbstract:The success of invasive alien and common native species may be explained by the same underlying mechanisms. Differences in Intraspecific Competition as well as differences in plant–soil feedback have been put forward as potential determinants of plant success. We teased apart the relative roles of Competition and plant–soil feedback in a greenhouse experiment with 30 common and rare alien and native species from nine plant families. We tested whether plant biomass decreased less for common than rare species, regardless of origin, when grown at higher relative frequencies (1, 3 or 6 out of 9 plants per pot) in a community and in soil previously conditioned by the same species at different frequencies (0, 1, 3 or 6 out of 9 plants per pot) in an orthogonal design for these two factors. Plant survival decreased slightly, but non-significantly, for all species when grown in soil previously occupied by conspecifics. Among surviving plants, we found a decrease in biomass with increasing Intraspecific Competition across all species (regardless of origin or commonness), and alien species were more negatively affected by previous high plant frequency than native species, but only marginally significantly so. Our findings suggest that, while Intraspecific Competition limits individual biomass in a density-dependent manner, these effects do not depend on species origin or commonness. Notably, alien species but not natives showed a decrease in performance when grown in soil pre-conditioned with a higher frequency of conspecifics. In conclusion, soil-borne pathogen accumulation might be weak in its effects on plant performance compared to Intraspecific Competition, with neither being clearly linked to species commonness.
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effects of Intraspecific Competition on size variation and reproductive allocation in a clonal plant
Oikos, 2001Co-Authors: Mark Van Kleunen, Markus Fischer, Bernhard SchmidAbstract:Clonal plants grow in diameter rather than height, and therefore Competition among genets is likely to be symmetric and to result in smaller variation in size of genets than in non-clonal plants. Moreover, clonal plants can reproduce both sexually and vegetatively. We studied the effects of density on the size of rosettes and of clones, variation in the size of rosettes and of clones, and allocation to sexual and vegetative reproduction in the clonal herb Ranunculus reptans. We grew plants from an artificial population of R. reptans in 32 trays at two densities. After four months, differences in density were still apparent, although clones in the low-density treatment had on average 155% more rosettes and 227% more rooted rosettes than clones in the high-density treatment. The coefficient of variation of these measures of clone size was 15% and 83% higher, respectively, in the low-density treatment. This indicates that Intraspecific Competition among clones of R. reptans is symmetric and increases the effective population size. Rooted rosettes were larger and varied more in size in the low-density treatment. The relative allocation of the populations to sexual and to vegetative reproduction was 19% and 13% higher, respectively, in the high-density treatment. Moreover, seeds produced in the high-density treatment had a 24% higher mass and a 7% higher germination percentage. This suggests that with increasing density, allocation to sexual reproduction increases more than allocation to vegetative reproduction in R. reptans, which corresponds to the response of some other species with a spreading growth form but not of species with a compact growth form. We conclude that Intraspecific Competition is an important factor in the life-history evolution of R. reptans because Intraspecific Competition affects its clonal life-history traits and may affect evolutionary processes such as genetic drift and selection through its effect on the effective population size.
Feihai Yu - One of the best experts on this subject based on the ideXlab platform.
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Effects of physical space and nutrients on the growth and Intraspecific Competition of a floating fern
Aquatic Ecology, 2019Co-Authors: Chao Si, Li-min Zhang, Feihai YuAbstract:Physical space, defined by its volume and shape, is considered a resource for plant growth, as a plant can be limited by physical space even when other resources (e.g., light, water and nutrients) are unlimited. However, the effect of physical space limitation on Intraspecific Competition of plants, especially floating plants, is not well understood. Here we tested the hypothesis that physical space affects the growth and Intraspecific Competition of floating plants, which is further influenced by the volume and surface area of the containers in which these plants are grown. We grew either one or four clonal fragments of a floating clonal fern, Azolla imbricata, in cylindrical containers differing in diameter and height (and thus surface area and volume) and filled with solutions containing the same or different nutrient concentrations. Biomass and number of clonal fragments of A. imbricata were higher in the container with the larger diameter and thus water surface area, but were not significantly affected by the height/volume of the container. Biomass and number of clonal fragments were reduced by Intraspecific Competition and tended to increase first and then decreased with increasing nutrient concentration. Increasing nutrient concentration inhibited the growth and then reduced Intraspecific Competition of A. imbricata, but the diameter or height/volume of the container had no effect. Our findings suggest that nutrient levels can alter Intraspecific Competition of plants, but physical space may not.
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nitrogen addition increases Intraspecific Competition in the invasive wetland plant alternanthera philoxeroides but not in its native congener alternanthera sessilis
Plant Species Biology, 2015Co-Authors: Ao Wang, Xingxing Jiang, Qiuqiu Zhang, Jian Zhou, Hongli Li, Mingxiang Zhang, Feihai YuAbstract:Nitrogen is often released in pulses with different frequencies, and N supply pulses may affect growth, reproduction, and biomass allocation of plants. However, few studies have examined how N supply pulses affect Intraspecific Competition of clonal plants and whether such an effect depends on the N supply amount. We grew one (no Competition) or 12 ramets (with Intraspecific Competition) of both an invasive clonal plant Alternanthera philoxeroides and its native congener Alternanthera sessilis in five different N treatments: control (no N addition), low/high amount with low/high frequencies (pulses). Nitrogen addition significantly increased the growth of both species, while Intraspecific Competition decreased it. Nitrogen addition significantly increased Intraspecific competitive intensity of A. philoxeroides as measured by the log response ratio of growth traits, but did not affect that of A. sessilis. Despite the N supply amount, N pulses had little effect on the growth and thus Intraspecific Competition of the two species. Therefore, increasing N deposition may change population structure and dynamics and the invasion succession of A. philoxeroides, but changes in N pulses may not.
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effects of clonal fragmentation on Intraspecific Competition of a stoloniferous floating plant
Plant Biology, 2014Co-Authors: P N Wang, Yingshou Xu, Bicheng Dong, Feihai YuAbstract:Disturbance is common and can fragment clones of plants. Clonal fragmentation may affect the density and growth of ramets so that it could alter Intraspecific Competition. To test this hypothesis, we grew one (low density), five (medium density) or nine (high density) parent ramets of the floating invasive plant Pistia stratiotes in buckets, and newly produced offspring ramets were either severed (with fragmentation) or remained connected to parent ramets (no fragmentation). Increasing density reduced biomass of the whole clone (i.e. parent ramet plus its offspring ramets), showing intense Intraspecific Competition. Fragmentation decreased biomass of offspring ramets, but increased biomass of parent ramets and the whole clone, suggesting significant resource translocation from parent to offspring ramets when clones were not fragmented. There was no interaction effect of density x fragmentation on biomass of the whole clone, and fragmentation did not affect Competition intensity index. We conclude that clonal fragmentation does not alter Intraspecific Competition between clones of P. stratiotes, but increases biomass production of the whole clone. Thus, fragmentation may contribute to its interspecific competitive ability and invasiveness, and intentional fragmentation should not be recommended as a measure to stop the rapid growth of this invasive species.
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spatial heterogeneity in light supply affects Intraspecific Competition of a stoloniferous clonal plant
PLOS ONE, 2012Co-Authors: P N Wang, Maihe Li, Feihai YuAbstract:Spatial heterogeneity in light supply is common in nature. Many studies have examined the effects of heterogeneous light supply on growth, morphology, physiology and biomass allocation of clonal plants, but few have tested those effects on Intraspecific Competition. In a greenhouse experiment, we grew one (no Competition) or nine ramets (with Intraspecific Competition) of a stoloniferous clonal plant, Duchesnea indica, in three homogeneous light conditions (high, medium and low light intensity) and two heterogeneous ones differing in patch size (large and small patch treatments). The total light in the two heterogeneous treatments was the same as that in the homogeneous medium light treatment. Both decreasing light intensity and Intraspecific Competition significantly decreased the growth (biomass, number of ramets and total stolon length) of D. indica. As compared with the homogeneous medium light treatment, the large patch treatment significantly increased the growth of D. indica without Intraspecific Competition. However, the growth of D. indica with Competition did not differ among the homogeneous medium light, the large and the small patch treatments. Consequently, light heterogeneity significantly increased Intraspecific Competition intensity, as measured by the decreased log response ratio. These results suggest that spatial heterogeneity in light supply can alter Intraspecific interactions of clonal plants.
Dang H Nguyen - One of the best experts on this subject based on the ideXlab platform.
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Persistence in Stochastic Lotka–Volterra Food Chains with Intraspecific Competition
Bulletin of Mathematical Biology, 2018Co-Authors: Alexandru Hening, Dang H NguyenAbstract:This paper is devoted to the analysis of a simple Lotka–Volterra food chain evolving in a stochastic environment. It can be seen as the companion paper of Hening and Nguyen (J Math Biol 76:697–754, 2018b ) where we have characterized the persistence and extinction of such a food chain under the assumption that there is no Intraspecific Competition among predators. In the current paper, we focus on the case when all the species experience intraCompetition. The food chain we analyze consists of one prey and $$n-1$$ n - 1 predators. The j th predator eats the $$j-1$$ j - 1 st species and is eaten by the $$j+1$$ j + 1 st predator; this way each species only interacts with at most two other species—the ones that are immediately above or below it in the trophic chain. We show that one can classify, based on the invasion rates of the predators (which we can determine from the interaction coefficients of the system via an algorithm), which species go extinct and which converge to their unique invariant probability measure. We obtain stronger results than in the case with no Intraspecific Competition because in this setting we can make use of the general results of Hening and Nguyen (Ann Appl Probab 28:1893–1942, 2018a ). Unlike most of the results available in the literature, we provide an in-depth analysis for both non-degenerate and degenerate noise. We exhibit our general results by analyzing trophic cascades in a plant–herbivore–predator system and providing persistence/extinction criteria for food chains of length $$n\le 4$$ n ≤ 4 .
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persistence in stochastic lotka volterra food chains with Intraspecific Competition
Bulletin of Mathematical Biology, 2018Co-Authors: Alexandru Hening, Dang H NguyenAbstract:This paper is devoted to the analysis of a simple Lotka–Volterra food chain evolving in a stochastic environment. It can be seen as the companion paper of Hening and Nguyen (J Math Biol 76:697–754, 2018b) where we have characterized the persistence and extinction of such a food chain under the assumption that there is no Intraspecific Competition among predators. In the current paper, we focus on the case when all the species experience intraCompetition. The food chain we analyze consists of one prey and $$n-1$$ predators. The jth predator eats the $$j-1$$ st species and is eaten by the $$j+1$$ st predator; this way each species only interacts with at most two other species—the ones that are immediately above or below it in the trophic chain. We show that one can classify, based on the invasion rates of the predators (which we can determine from the interaction coefficients of the system via an algorithm), which species go extinct and which converge to their unique invariant probability measure. We obtain stronger results than in the case with no Intraspecific Competition because in this setting we can make use of the general results of Hening and Nguyen (Ann Appl Probab 28:1893–1942, 2018a). Unlike most of the results available in the literature, we provide an in-depth analysis for both non-degenerate and degenerate noise. We exhibit our general results by analyzing trophic cascades in a plant–herbivore–predator system and providing persistence/extinction criteria for food chains of length $$n\le 4$$ .
Lukas Eigentler - One of the best experts on this subject based on the ideXlab platform.
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Species coexistence in vegetation patterns facilitated by the interplay of spatial self-organisation and Intraspecific Competition
bioRxiv, 2020Co-Authors: Lukas EigentlerAbstract:The exploration of mechanisms that enable species coexistence under Competition for a sole limiting resource is widespread across ecology. Two examples of such facilitative processes are Intraspecific Competition and spatial self-organisation. A classical example of an ecosystem governed by the latter is dryland vegetation patterns. Previous theoretical investigations have explained coexistence in patterned vegetation by making strong assumptions on the differences between species (e.g. contrasting dispersal behaviours or different functional responses to soil moisture). In this paper, I show that the interplay between the competitive effects of Intraspecific Competition and the facilitative nature of self-organisation forms a coexistence mechanism that does not rely on species-specific assumptions. I use an ecohydrological reaction-advection-diffusion system that captures the interactions of two plant species with an explicitly modelled resource to show that coexistence relies on a balance between species9 colonisation abilities and their local competitiveness, provided Intraspecific Competition is sufficiently strong. Crucially, the requirements on species9 self-limitation for coexistence to occur differ on opposite ends of the precipitation (resource input) spectrum. For low resource levels, coexistence is facilitated by strong Intraspecific dynamics of the species superior in its colonisation abilities, but for larger volumes of resource input, strong Intraspecific Competition of the locally superior species enables coexistence. Results presented in this paper also capture the empirically observed spatial species distribution within bands of vegetation and propose differences in plants9 dispersal behaviour as its cause.
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Intraspecific Competition in models for vegetation patterns: Decrease in resilience to aridity and facilitation of species coexistence
Ecological Complexity, 2020Co-Authors: Lukas EigentlerAbstract:Abstract Patterned vegetation is a characteristic feature of many dryland ecosystems. While plant densities on the ecosystem-wide scale are typically low, a spatial self-organisation principle leads to the occurrence of alternating patches of high biomass and patches of bare soil. Nevertheless, Intraspecific Competition dynamics other than Competition for water over long spatial scales are commonly ignored in mathematical models for vegetation patterns. In this paper, I address the impact of local Intraspecific Competition on a modelling framework for banded vegetation patterns. Firstly, I show that in the context of a single-species model, neglecting local Intraspecific Competition leads to an overestimation of a patterned ecosystem’s resilience to increases in aridity. Secondly, in the context of a multispecies model, I argue that local Intraspecific Competition is a key element in the successful capture of species coexistence in model solutions representing a vegetation pattern. For both models, a detailed bifurcation analysis is presented to analyse the onset, existence and stability of patterns. Besides the strengths of local Intraspecific Competition, also the difference between two species has a significant impact on the bifurcation structure, providing crucial insights into the complex ecosystem dynamics. Predictions on future ecosystem dynamics presented in this paper, especially on pattern onset and pattern stability, can aid the development of conservation programs.
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Intraspecific Competition in models for vegetation patterns: decrease in resilience to aridity and facilitation of species coexistence
arXiv: Populations and Evolution, 2020Co-Authors: Lukas EigentlerAbstract:Patterned vegetation is a characteristic feature of many dryland ecosystems. While plant densities on the ecosystem-wide scale are typically low, a spatial self-organisation principle leads to the occurrence of alternating patches of high biomass and patches of bare soil. Nevertheless, Intraspecific Competition dynamics other than Competition for water over long spatial scales are commonly ignored in mathematical models for vegetation patterns. In this chapter, I address the impact of local Intraspecific Competition on a modelling framework for banded vegetation patterns. Firstly, I show that in the context of a single-species model, neglecting local Intraspecific Competition leads to an overestimation of a patterned ecosystem's resilience to increases in aridity. Secondly, in the context of a multispecies model, I argue that local Intraspecific Competition is a key element in the successful capture of species coexistence in model solutions representing a vegetation pattern. For both models, a detailed bifurcation analysis is presented to analyse the onset, existence and stability of patterns. Besides the strengths of local Intraspecific Competition, also the the difference between two species has a significant impact on the bifurcation structure, providing crucial insights into the complex ecosystem dynamics. Predictions on future ecosystem dynamics presented in this chapter, especially on pattern onset and pattern stability, can aid the development of conservation programs.