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Taylor MA, Cooper MD, Sellamuthu R, Braun P, Migneault A, Browning A, Perry E, Schmitt J. Interacting effects of genetic variation for seed dormancy and flowering time on phenology, life history, and fitness of experimental Arabidopsis thaliana populations over multiple generations in the field. THE NEW PHYTOLOGIST 2017; 216:291-302. [PMID: 28752957 DOI: 10.1111/nph.14712] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
Major alleles for seed dormancy and flowering time are well studied, and can interact to influence seasonal timing and fitness within generations. However, little is known about how this interaction controls phenology, life history, and population fitness across multiple generations in natural seasonal environments. To examine how seed dormancy and flowering time shape annual plant life cycles over multiple generations, we established naturally dispersing populations of recombinant inbred lines of Arabidopsis thaliana segregating early and late alleles for seed dormancy and flowering time in a field experiment. We recorded seasonal phenology and fitness of each genotype over 2 yr and several generations. Strong seed dormancy suppressed mid-summer germination in both early- and late-flowering genetic backgrounds. Strong dormancy and late-flowering genotypes were both necessary to confer a winter annual life history; other genotypes were rapid-cycling. Strong dormancy increased within-season fecundity in an early-flowering background, but decreased it in a late-flowering background. However, there were no detectable differences among genotypes in population growth rates. Seasonal phenology, life history, and cohort fitness over multiple generations depend strongly upon interacting genetic variation for dormancy and flowering. However, similar population growth rates across generations suggest that different life cycle genotypes can coexist in natural populations.
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Affiliation(s)
- Mark A Taylor
- University of California at Davis, Davis, CA, 95616, USA
| | | | | | - Peter Braun
- Brown University, Providence, RI, 02912, USA
- California State University at San Bernardino, San Bernardino, CA, 92407, USA
| | | | | | - Emily Perry
- Brown University, Providence, RI, 02912, USA
| | - Johanna Schmitt
- University of California at Davis, Davis, CA, 95616, USA
- Brown University, Providence, RI, 02912, USA
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Diniz ÉS, Carvalho WAC, Santos RM, Gastauer M, Garcia PO, Fontes MAL, Coelho PA, Moreira AM, Menino GCO, Oliveira-Filho AT. Long-term monitoring of diversity and structure of two stands of an Atlantic Tropical Forest. Biodivers Data J 2017:e13564. [PMID: 28848371 PMCID: PMC5554867 DOI: 10.3897/bdj.5.e13564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/12/2017] [Indexed: 11/12/2022] Open
Abstract
Background This study aimed to report the long-term monitoring of diversity and structure of the tree community in a protected semideciduous Atlantic Forest in the South of Minas Gerais State, Southeast Brazil. The study was conducted in two stands (B and C), each with 26 and 38 10 m x 30 m plots. Censuses of stand B were conducted in 2000, 2005 and 2011, and stand C in 2001, 2006 and 2011. In both stands, the most abundant and important species for biomass accumulation over the inventories were trees larger than 20 cm of diameter, which characterize advanced successional stage within the forest. New information The two surveyed stands within the studied forest presented differences in structure, diversity and species richness over the time.
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Affiliation(s)
- Écio Souza Diniz
- Laboratory of Plant Ecology and Evolution, Department of Plant Biology, Federal University of Viçosa, Viçosa, Brazil
| | | | - Rubens Manoel Santos
- Science Forest Department, Federal University of Lavras, Lavras, Brazil, Lavras, Brazil
| | | | - Paulo Oswaldo Garcia
- Instituto Federal de Educação, Ciência e Tecnologia Sul de Minas Gerais - Campus Muzambinho, Muzambinho, Brazil
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103
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Donohue K, Schmitt J. THE GENETIC ARCHITECTURE OF PLASTICITY TO DENSITY IN
IMPATIENS CAPENSIS. Evolution 2017; 53:1377-1386. [PMID: 28565560 DOI: 10.1111/j.1558-5646.1999.tb05402.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/1998] [Accepted: 05/06/1999] [Indexed: 11/28/2022]
Affiliation(s)
- Kathleen Donohue
- Department of Ecology and Evolutionary Biology Brown University Box G‐W Providence Rhode Island 02912
| | - Johanna Schmitt
- Department of Ecology and Evolutionary Biology Brown University Box G‐W Providence Rhode Island 02912
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104
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Thiede DA. MATERNAL INHERITANCE AND ITS EFFECT ON ADAPTIVE EVOLUTION: A QUANTITATIVE GENETIC ANALYSIS OF MATERNAL EFFECTS IN A NATURAL PLANT POPULATION. Evolution 2017; 52:998-1015. [PMID: 28565233 DOI: 10.1111/j.1558-5646.1998.tb01829.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/1997] [Accepted: 04/08/1998] [Indexed: 11/28/2022]
Abstract
A mother can influence a trait in her offspring both by the genes she transmits (Mendelian inheritance) and by maternal attributes that directly affect that trait in her offspring (maternal inheritance). Maternal inheritance can alter the direction, rate, and duration of adaptive evolution from standard Mendelian models and its impact on adaptive evolution is virtually unexplored in natural populations. In a hierarchical quantitative genetic analysis to determine the magnitude and structure of maternal inheritance in the winter annual plant, Collinsia verna, I consider three potential models of inheritance. These range from a standard Mendelian model estimating only direct (i.e., Mendelian) additive and environmental variance components to a maternal inheritance model estimating six additive and environmental variance components: direct additive (σAo2) and environmental (σEo2) variances; maternal additive (σAm2) and environmental (σEm2) variances; and the direct-maternal additive (σApAm) and environmental (σEm2) covariances. The structure of maternal inheritance differs among the 10 traits considered at four stages in the life cycle. Early in the life cycle, seed weight and embryo weight display substantial σAm2, a negative σAoAm, and a positive σEoEm. Subsequently, cotyledon diameter displays σAo2 and σAm2 of roughly the same magnitude and negative σAoAm. For fall rosettes, leaf number and length are best described by a Mendelian model. In the spring, leaf length displays maternal inheritance with significant σAo2 and σAm2 and a negative σAoAm. All maternally inherited traits show significant negative σAoAm. Predicted response to selection under maternal inheritance depends on σAo2 and σAm2 as well as σAoAm. Negative σAoAm results in predicted responses in the opposite direction to selection for seed weight and embryo weight and predicted responses near zero for all subsequent maternally inherited traits. Maternal inheritance persists through the life cycle of this annual plant for a number of size-related traits and will alter the direction and rate of evolutionary response in this population.
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Affiliation(s)
- Denise A Thiede
- W. K. Kellogg Biological Station and Department of Botany and Plant Pathology, Michigan State University, Hickory Corners, Michigan, 49060
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105
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Gilbert B, Levine JM. Ecological drift and the distribution of species diversity. Proc Biol Sci 2017; 284:20170507. [PMID: 28566486 PMCID: PMC5454268 DOI: 10.1098/rspb.2017.0507] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 04/27/2017] [Indexed: 11/12/2022] Open
Abstract
Ecological drift causes species abundances to fluctuate randomly, lowering diversity within communities and increasing differences among otherwise equivalent communities. Despite broad interest in ecological drift, ecologists have little experimental evidence of its consequences in nature, where competitive forces modulate species abundances. We manipulated drift by imposing 40-fold variation in the size of experimentally assembled annual plant communities and holding their edge-to-interior ratios comparable. Drift over three generations was greater than predicted by neutral models, causing high extinction rates and fast divergence in composition among smaller communities. Competitive asymmetries drove populations of most species to small enough sizes that demographic stochasticity could markedly influence dynamics, increasing the importance of drift in communities. The strong effects of drift occurred despite stabilizing niche differences, which cause species to have greater population growth rates when at low local abundance. Overall, the importance of ecological drift appears greater in non-neutral communities than previously recognized, and varies with community size and the type and strength of density dependence.
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Affiliation(s)
- Benjamin Gilbert
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Jonathan M Levine
- Institute for Integrative Biology, Eidgenössiche Technische Hochschule Zurich, 8092 Zurich, Switzerland
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106
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Schwinning S, Meckel H, Reichmann LG, Polley HW, Fay PA. Accelerated development in Johnsongrass seedlings (Sorghum halepense) suppresses the growth of native grasses through size-asymmetric competition. PLoS One 2017; 12:e0176042. [PMID: 28467488 PMCID: PMC5415093 DOI: 10.1371/journal.pone.0176042] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 04/04/2017] [Indexed: 11/19/2022] Open
Abstract
Invasive plant species often dominate native species in competition, augmenting other potential advantages such as release from natural enemies. Resource pre-emption may be a particularly important mechanism for establishing dominance over competitors of the same functional type. We hypothesized that competitive success of an exotic grass against native grasses is mediated by establishing an early size advantage. We tested this prediction among four perennial C4 warm-season grasses: the exotic weed Johnsongrass (Sorghum halepense), big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparius) and switchgrass (Panicum virgatum). We predicted that a) the competitive effect of Johnsongrass on target species would be proportional to their initial biomass difference, b) competitive effect and response would be negatively correlated and c) soil fertility would have little effect on competitive relationships. In a greenhouse, plants of the four species were grown from seed either alone or with one Johnsongrass neighbor at two fertilizer levels and periodically harvested. The first two hypotheses were supported: The seedling biomass of single plants at first harvest (50 days after seeding) ranked the same way as the competitive effect of Johnsongrass on target species: Johnsongrass < big bluestem < little bluestem/switchgrass, while Johnsongrass responded more strongly to competition from Johnsongrass than from native species. At final harvest, native plants growing with Johnsongrass attained between 2–5% of their single-plant non-root biomass, while Johnsongrass growing with native species attained 89% of single-plant non-root biomass. Fertilization enhanced Johnsongrass’ competitive effects on native species, but added little to the already severe competitive suppression. Accelerated early growth of Johnsongrass seedlings relative to native seedlings appeared to enable subsequent resource pre-emption. Size-asymmetric competition and resource-pre-emption may be a critical mechanism by which exotic invasive species displace functionally similar native species and alter the functional dynamics of native communities.
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Affiliation(s)
- Susanne Schwinning
- Department of Biology, Texas State University, San Marcos, Texas, United States of America
- * E-mail:
| | - Heather Meckel
- Department of Biology, Texas State University, San Marcos, Texas, United States of America
| | - Lara G. Reichmann
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America
- USDA-ARS Grassland, Soil and Water Research Laboratory, Temple, Texas, United States of America
| | - H. Wayne Polley
- USDA-ARS Grassland, Soil and Water Research Laboratory, Temple, Texas, United States of America
| | - Philip A. Fay
- USDA-ARS Grassland, Soil and Water Research Laboratory, Temple, Texas, United States of America
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107
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Prevalence of Inter-Tree Competition and Its Role in Shaping the Community Structure of a Natural Mongolian Scots Pine (Pinus sylvestris var. mongolica) Forest. FORESTS 2017. [DOI: 10.3390/f8030084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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108
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Zhang C, Cheng Y, He H, Gao L, Liang J, Zhao X. Structural drivers of biomass dynamics in two temperate forests in China. Ecosphere 2017. [DOI: 10.1002/ecs2.1752] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Chunyu Zhang
- Key Laboratory for Forest Resources & Ecosystem Processes of Beijing; Beijing Forestry University; Beijing 100083 China
| | - Yanxia Cheng
- Key Laboratory for Forest Resources & Ecosystem Processes of Beijing; Beijing Forestry University; Beijing 100083 China
| | - Huaijiang He
- Key Laboratory for Forest Resources & Ecosystem Processes of Beijing; Beijing Forestry University; Beijing 100083 China
| | - Lushuang Gao
- Key Laboratory for Forest Resources & Ecosystem Processes of Beijing; Beijing Forestry University; Beijing 100083 China
| | - Jingjing Liang
- School of Natural Resources; West Virginia University; Morgantown West Virginia 26506 USA
| | - Xiuhai Zhao
- Key Laboratory for Forest Resources & Ecosystem Processes of Beijing; Beijing Forestry University; Beijing 100083 China
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109
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Ringselle B, Prieto-Ruiz I, Andersson L, Aronsson H, Bergkvist G. Elymus repens biomass allocation and acquisition as affected by light and nutrient supply and companion crop competition. ANNALS OF BOTANY 2017; 119:477-485. [PMID: 28025285 PMCID: PMC5314646 DOI: 10.1093/aob/mcw228] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 09/03/2016] [Accepted: 09/19/2016] [Indexed: 05/17/2023]
Abstract
BACKGROUND AND AIMS Competitive crops are a central component of resource-efficient weed control, especially for problematic perennial weeds such as Elymus repens Competition not only reduces total weed biomass, but denial of resources can also change the allocation pattern - potentially away from the underground storage organs that make perennial weeds difficult to control. Thus, the competition mode of crops may be an important component in the design of resource-efficient cropping systems. Our aim was to determine how competition from companion crops with different modes of competition affect E. repens biomass acquisition and allocation and discuss that in relation to how E. repens responds to different levels of light and nutrient supply. METHODS Greenhouse experiments were conducted with E. repens growing in interspecific competition with increasing density of perennial ryegrass or red clover, or growing at three levels of both light and nutrient supply. KEY RESULTS Elymus repens total biomass decreased with increasing biomass of the companion crop and the rate of decrease was higher with red clover than with perennial ryegrass, particularly for E. repens rhizome biomass. A reduced nutrient supply shifted E. repens allocation towards below-ground biomass while a reduced light supply shifted it towards shoot biomass. Red clover caused no change in E. repens allocation pattern, while ryegrass mostly shifted the allocation towards below-ground biomass, but the change was not correlated with ryegrass biomass. CONCLUSIONS The companion crop mode of competition influences both the suppression rate of E. repens biomass acquisition and the likelihood of shifts in E. repens biomass allocation.
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Affiliation(s)
- Björn Ringselle
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Box 7043, SE-750 07 Uppsala, Sweden
| | - Inés Prieto-Ruiz
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Box 7043, SE-750 07 Uppsala, Sweden
| | - Lars Andersson
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Box 7043, SE-750 07 Uppsala, Sweden
| | - Helena Aronsson
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Box 7014, SE-750 07 Uppsala, Sweden
| | - Göran Bergkvist
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Box 7043, SE-750 07 Uppsala, Sweden
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110
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Topography-associated thermal gradient predicts warming effects on woody plant structural diversity in a subtropical forest. Sci Rep 2017; 7:40387. [PMID: 28067326 PMCID: PMC5220297 DOI: 10.1038/srep40387] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/06/2016] [Indexed: 11/09/2022] Open
Abstract
Understanding global warming effects on forest ecosystems will help policy-makers and forest managers design forest management and biodiversity conservation strategies. We examined the change in woody plant structural diversity in response to topography-associated thermal gradients in a subtropical forest with diverse abundance patterns. We found that energy distribution in a warming trend across slopes had significant effects on woody plant structural diversity. Except for total basal area of the adult trees, plant structural diversity significantly decreased with the increase of heat load. Heat load is significantly and negatively correlated with number of stems, number of species, and the number of stems of the most abundant species (Nmax) for seedlings, saplings, and individuals of all sizes. For the adult trees, heat load is significantly and positively correlated with number of stems and Nmax, and negatively but not significantly with number of species, indicating that large trees may not be as sensitive as seedlings and saplings to warming. Partial correlation analysis, having controlled for elevation, strengthened those relations in most cases. Our results reveal that warming will increase community productivity by enhancing the growth of large trees, but decrease species diversity and inhibit the regeneration of tree seedlings and saplings.
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111
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Alam SA, Huang JG, Stadt KJ, Comeau PG, Dawson A, Gea-Izquierdo G, Aakala T, Hölttä T, Vesala T, Mäkelä A, Berninger F. Effects of Competition, Drought Stress and Photosynthetic Productivity on the Radial Growth of White Spruce in Western Canada. FRONTIERS IN PLANT SCIENCE 2017; 8:1915. [PMID: 29163627 PMCID: PMC5681961 DOI: 10.3389/fpls.2017.01915] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 10/23/2017] [Indexed: 05/05/2023]
Abstract
Understanding the complex interactions of competition, climate warming-induced drought stress, and photosynthetic productivity on the radial growth of trees is central to linking climate change impacts on tree growth, stand structure and in general, forest productivity. Using a mixed modeling approach, a stand-level photosynthetic production model, climate, stand competition and tree-ring data from mixedwood stands in western Canada, we investigated the radial growth response of white spruce [Picea glauca (Moench.) Voss] to simulated annual photosynthetic production, simulated drought stress, and tree and stand level competition. The long-term (~80-year) radial growth of white spruce was constrained mostly by competition, as measured by total basal area, with minor effects from drought. There was no relation of competition and drought on tree growth but dominant trees increased their growth more strongly to increases in modeled photosynthetic productivity, indicating asymmetric competition. Our results indicate a co-limitation of drought and climatic factors inhibiting photosynthetic productivity for radial growth of white spruce in western Canada. These results illustrate how a modeling approach can separate the complex factors regulating both multi-decadal average radial growth and interannual radial growth variations of white spruce, and contribute to advance our understanding on sustainable management of mixedwood boreal forests in western Canada.
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Affiliation(s)
- Syed A. Alam
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Department of Physics, University of Helsinki, Helsinki, Finland
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Jian-Guo Huang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- *Correspondence: Jian-Guo Huang
| | - Kenneth J. Stadt
- Forest Management Branch, Alberta Agriculture and Forestry, Edmonton, AB, Canada
| | - Philip G. Comeau
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - Andria Dawson
- Department of General Education, Mount Royal University, Calgary, AB, Canada
| | | | - Tuomas Aakala
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Teemu Hölttä
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Timo Vesala
- Department of Physics, University of Helsinki, Helsinki, Finland
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Annikki Mäkelä
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Frank Berninger
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
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112
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Rasmussen CR, Weiner J. Modelling the effect of size-asymmetric competition on size inequality: Simple models with two plants. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2016.10.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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114
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Tracey AJ, Stephens KA, Schamp BS, Aarssen LW. What does body size mean, from the "plant's eye view"? Ecol Evol 2016; 6:7344-7351. [PMID: 28725402 PMCID: PMC5513261 DOI: 10.1002/ece3.2476] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 08/10/2016] [Accepted: 08/18/2016] [Indexed: 11/21/2022] Open
Abstract
Alternative metrics exist for representing variation in plant body size, but the vast majority of previous research for herbaceous plants has focused on dry mass. Dry mass provides a reasonably accurate and easily measured estimate for comparing relative capacity to convert solar energy into stored carbon. However, from a "plant's eye view", its experience of its local biotic environment of immediate neighbors (especially when crowded) may be more accurately represented by measures of "space occupancy" (S-O) recorded in situ-rather than dry mass measured after storage in a drying oven. This study investigated relationships between dry mass and alternative metrics of S-O body size for resident plants sampled from natural populations of herbaceous species found in Eastern Ontario. Plant height, maximum lateral canopy extent, and estimated canopy area and volume were recorded in situ (in the field)-and both fresh and dry mass were recorded in the laboratory-for 138 species ranging widely in body size and for 20 plants ranging widely in body size within each of 10 focal species. Dry mass and fresh mass were highly correlated (r2 > .95) and isometric, suggesting that for some studies, between-species (or between-plant) variation in water content may be unimportant and fresh mass can therefore substitute for dry mass. However, several relationships between dry mass and other S-O body size metrics showed allometry-that is, plants with smaller S-O body size had disproportionately less dry mass. In other words, they have higher "body mass density" (BMD) - more dry mass per unit S-O body size. These results have practical importance for experimental design and methodology as well as implications for the interpretation of "reproductive economy"-the capacity to produce offspring at small body sizes-because fecundity and dry mass (produced in the same growing season) typically have a positive, isometric relationship. Accordingly, the allometry between dry mass and S-O body size reported here suggests that plants with smaller S-O body size-because of higher BMD-may produce fewer offspring, but less than proportionately so; in other words, they may produce more offspring per unit of body size space occupancy.
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115
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Maron JL, Laney Smith A, Ortega YK, Pearson DE, Callaway RM. Negative plant‐soil feedbacks increase with plant abundance, and are unchanged by competition. Ecology 2016; 97:2055-2063. [DOI: 10.1002/ecy.1431] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 02/27/2016] [Accepted: 03/22/2016] [Indexed: 11/06/2022]
Affiliation(s)
- John L. Maron
- Division of Biological Sciences University of Montana Missoula Montana 59812 USA
| | - Alyssa Laney Smith
- Division of Biological Sciences University of Montana Missoula Montana 59812 USA
- Department of Plant Pathology, Physiology and Weed Science Virginia Polytechnic Institute and State University Blacksburg Virginia 24061 USA
| | - Yvette K. Ortega
- Rocky Mountain Research Station U.S.D.A. Forest Service Missoula Montana 59801 USA
| | - Dean E. Pearson
- Division of Biological Sciences University of Montana Missoula Montana 59812 USA
- Rocky Mountain Research Station U.S.D.A. Forest Service Missoula Montana 59801 USA
| | - Ragan M. Callaway
- Division of Biological Sciences and the Institute on Ecosystems University of Montana Missoula Montana 59812 USA
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DeMalach N, Zaady E, Weiner J, Kadmon R. Size asymmetry of resource competition and the structure of plant communities. JOURNAL OF ECOLOGY 2016; 104:899-910. [PMID: 0 DOI: 10.1111/1365-2745.12557] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- Niv DeMalach
- Department of Ecology, Evolution and Behavior; The Hebrew University of Jerusalem; Givat Ram Jerusalem 91904 Israel
| | - Eli Zaady
- Department of Natural Resources; Institute of Plant Sciences; Agriculture Research Organization; Ministry of Agriculture; Gilat Research Center; Beer Sheva 85280 Israel
| | - Jacob Weiner
- Department of Plant and Environmental Sciences; University of Copenhagen; Thorvaldsensvej 40 DK-1871 Frederiksberg Denmark
| | - Ronen Kadmon
- Department of Ecology, Evolution and Behavior; The Hebrew University of Jerusalem; Givat Ram Jerusalem 91904 Israel
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Siebenkäs A, Schumacher J, Roscher C. Resource Availability Alters Biodiversity Effects in Experimental Grass-Forb Mixtures. PLoS One 2016; 11:e0158110. [PMID: 27341495 PMCID: PMC4920387 DOI: 10.1371/journal.pone.0158110] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 06/12/2016] [Indexed: 11/18/2022] Open
Abstract
Numerous experiments, mostly performed in particular environments, have shown positive diversity-productivity relationships. Although the complementary use of resources is discussed as an important mechanism explaining diversity effects, less is known about how resource availability controls the strength of diversity effects and how this response depends on the functional composition of plant communities. We studied aboveground biomass production in experimental monocultures, two- and four-species mixtures assembled from two independent pools of four perennial grassland species, each representing two functional groups (grasses, forbs) and two growth statures (small, tall), and exposed to different combinations of light and nutrient availability. On average, shade led to a decrease in aboveground biomass production of 24% while fertilization increased biomass production by 36%. Mixtures were on average more productive than expected from their monocultures (relative yield total, RYT>1) and showed positive net diversity effects (NE: +34% biomass increase; mixture minus mean monoculture biomass). Both trait-independent complementarity effects (TICE: +21%) and dominance effects (DE: +12%) positively contributed to net diversity effects, while trait-dependent complementarity effects were minor (TDCE: +1%). Shading did not alter diversity effects and overyielding. Fertilization decreased RYT and the proportion of biomass gain through TICE and TDCE, while DE increased. Diversity effects did not increase with species richness and were independent of functional group or growth stature composition. Trait-based analyses showed that the dominance of species with root and leaf traits related to resource conservation increased TICE. Traits indicating the tolerance of shade showed positive relationships with TDCE. Large DE were associated with the dominance of species with tall growth and low diversity in leaf nitrogen concentrations. Our field experiment shows that positive diversity effects are possible in grass-forb mixtures irrespective of differences in light availability, but that the chance for the complementary use of resources increases when nutrients are not available at excess.
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Affiliation(s)
- Alrun Siebenkäs
- UFZ, Helmholtz Centre for Environmental Research, Department of Community Ecology, Theodor-Lieser-Strasse 4, 06120, Halle, Germany
| | - Jens Schumacher
- Institute of Mathematics, Stochastics, Friedrich Schiller University Jena, Ernst-Abbe-Platz 2, 07743, Jena, Germany
| | - Christiane Roscher
- UFZ, Helmholtz Centre for Environmental Research, Physiological Diversity, Permoserstrasse 15, 04318, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
- * E-mail:
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Fazlioglu F, Al‐Namazi A, Bonser SP. Reproductive efficiency and shade avoidance plasticity under simulated competition. Ecol Evol 2016; 6:4947-57. [PMID: 27547325 PMCID: PMC4979719 DOI: 10.1002/ece3.2254] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/19/2016] [Accepted: 05/23/2016] [Indexed: 11/23/2022] Open
Abstract
Plant strategy and life‐history theories make different predictions about reproductive efficiency under competition. While strategy theory suggests under intense competition iteroparous perennial plants delay reproduction and semelparous annuals reproduce quickly, life‐history theory predicts both annual and perennial plants increase resource allocation to reproduction under intense competition. We tested (1) how simulated competition influences reproductive efficiency and competitive ability (CA) of different plant life histories and growth forms; (2) whether life history or growth form is associated with CA; (3) whether shade avoidance plasticity is connected to reproductive efficiency under simulated competition. We examined plastic responses of 11 herbaceous species representing different life histories and growth forms to simulated competition (spectral shade). We found that both annual and perennial plants invested more to reproduction under simulated competition in accordance with life‐history theory predictions. There was no significant difference between competitive abilities of different life histories, but across growth forms, erect species expressed greater CA (in terms of leaf number) than other growth forms. We also found that shade avoidance plasticity can increase the reproductive efficiency by capitalizing on the early life resource acquisition and conversion of these resources into reproduction. Therefore, we suggest that a reassessment of the interpretation of shade avoidance plasticity is necessary by revealing its role in reproduction, not only in competition of plants.
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Affiliation(s)
- Fatih Fazlioglu
- Evolution and Ecology Research CentreSchool of Biological, Earth and Environmental SciencesUNSW AustraliaSydneyNew South Wales2052Australia
| | - Ali Al‐Namazi
- Evolution and Ecology Research CentreSchool of Biological, Earth and Environmental SciencesUNSW AustraliaSydneyNew South Wales2052Australia
| | - Stephen P. Bonser
- Evolution and Ecology Research CentreSchool of Biological, Earth and Environmental SciencesUNSW AustraliaSydneyNew South Wales2052Australia
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119
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Chen Y, Wright SJ, Muller-Landau HC, Hubbell SP, Wang Y, Yu S. Positive effects of neighborhood complementarity on tree growth in a Neotropical forest. Ecology 2016; 97:776-85. [PMID: 27197403 DOI: 10.1890/15-0625.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Numerous grassland experiments have found evidence for a complementarity effect, an increase in productivity with higher plant species richness due to niche partitioning. However, empirical tests of complementarity in natural forests are rare. We conducted a spatially explicit analysis of 518 433 growth records for 274 species from a 50-ha tropical forest plot to test neighborhood complementarity, the idea that a tree grows faster when it is surrounded by more dissimilar neighbors. We found evidence for complementarity: focal tree growth rates increased by 39.8% and 34.2% with a doubling of neighborhood multi-trait dissimilarity and phylogenetic dissimilarity, respectively. Dissimilarity from neighbors in maximum height had the most important effect on tree growth among the six traits examined, and indeed, its effect trended much larger than that of the multitrait dissimilarity index. Neighborhood complementarity effects were strongest for light-demanding species, and decreased in importance with increasing shade tolerance of the focal individuals. Simulations demonstrated that the observed neighborhood complementarities were sufficient to produce positive stand-level biodiversity-productivity relationships. We conclude that neighborhood complementarity is important for productivity in this tropical forest, and that scaling down to individual-level processes can advance our understanding of the mechanisms underlying stand-level biodiversity-productivity relationships.
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120
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Complex network analysis reveals novel essential properties of competition among individuals in an even-aged plant population. ECOLOGICAL COMPLEXITY 2016. [DOI: 10.1016/j.ecocom.2016.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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121
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Xu GQ, McDowell NG, Li Y. A possible link between life and death of a xeric tree in desert. JOURNAL OF PLANT PHYSIOLOGY 2016; 194:35-44. [PMID: 26968083 DOI: 10.1016/j.jplph.2016.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 06/05/2023]
Abstract
Understanding the interactions between drought and tree ontogeny or size remains an essential research priority because size-specific mortality patterns have large impacts on ecosystem structure and function, determine forest carbon storage capacity, and are sensitive to climatic change. Here we investigate a xerophytic tree species (Haloxylon ammodendron (C.A. Mey.)) with which the changes in biomass allocation with tree size may play an important role in size-specific mortality patterns. Size-related changes in biomass allocation, root distribution, plant water status, gas exchange, hydraulic architecture and non-structural carbohydrate reserves of this xerophytic tree species were investigated to assess their potential role in the observed U-shaped mortality pattern. We found that excessively negative water potentials (<-4.7MPa, beyond the P50leaf of -4.1MPa) during prolonged drought in young trees lead to hydraulic failure; while the imbalance of photoassimilate allocation between leaf and root system in larger trees, accompanied with declining C reserves (<2% dry matter across four tissues), might have led to carbon starvation. The drought-resistance strategy of this species is preferential biomass allocation to the roots to improve water capture. In young trees, the drought-resistance strategy is not well developed, and hydraulic failure appears to be the dominant driver of mortality during drought. With old trees, excess root growth at the expense of leaf area may lead to carbon starvation during prolonged drought. Our results suggest that the drought-resistance strategy of this xeric tree is closely linked to its life and death: well-developed drought-resistance strategy means life, while underdeveloped or overdeveloped drought-resistance strategy means death.
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Affiliation(s)
- Gui-Qing Xu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China
| | - Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Yan Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China.
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122
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Helsen K, Hermy M, Honnay O. A test of priority effect persistence in semi-natural grasslands through the removal of plant functional groups during community assembly. BMC Ecol 2016; 16:22. [PMID: 27118382 PMCID: PMC4847182 DOI: 10.1186/s12898-016-0077-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 04/13/2016] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND It is known that during plant community assembly, the early colonizing species can affect the establishment, growth or reproductive success of later arriving species, often resulting in unpredictable assembly outcomes. These so called 'priority effects' have recently been hypothesized to work through niche-based processes, with early colonizing species either inhibiting the colonization of other species of the same niche through niche preemption, or affecting the colonization success of species of different niches through niche modification. With most work on priority effects performed in controlled, short-term mesocosm experiments, we have little insight in how niche preemption and niche modification processes interact to shape the community composition of natural vegetations. In this study, we used a functional trait approach to identify potential niche-based priority effects in restored semi-natural grasslands. More specifically, we imposed two treatments that strongly altered the community's functional trait composition; removal of all graminoid species and removal of all legume species, and we compared progressing assembly with unaltered control plots. RESULTS Our results showed that niche preemption effects can be, to a limited extent, relieved by species removal. This relief was observed for competitive grasses and herbs, but not for smaller grassland species. Although competition effects acting within functional groups (niche preemption) occurred for graminoids, there were no such effects for legumes. The removal of legumes mainly affected functionally unrelated competitive species, likely through niche modification effects of nitrogen fixation. On the other hand, and contrary to our expectations, species removal was after 4 years almost completely compensated by recolonization of the same species set, suggesting that priority effects persist after species removal, possibly through soil legacy effects. CONCLUSIONS Our results show that both niche modification and niche preemption priority effects can act together in shaping community composition in a natural grassland system. Although small changes in species composition occurred, the removal of specific functional groups was almost completely compensated by recolonization of the same species. This suggests that once certain species get established, it might prove difficult to neutralize their effect on assembly outcome, since their imposed priority effects might act long after their removal.
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Affiliation(s)
- Kenny Helsen
- />Plant Conservation and Population Biology, Department of Biology, University of Leuven, Arenbergpark 31, 3001 Heverlee, Belgium
- />Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7034 Trondheim, Norway
| | - Martin Hermy
- />Division Forest, Nature and Landscape Research, Department Earth and Environmental Sciences, University of Leuven, Celestijnenlaan 200E, 3001 Heverlee, Belgium
| | - Olivier Honnay
- />Plant Conservation and Population Biology, Department of Biology, University of Leuven, Arenbergpark 31, 3001 Heverlee, Belgium
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123
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Fadrique B, Feeley KJ. Commentary: Novel competitors shape species' responses to climate change. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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124
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Borgström P, Strengbom J, Viketoft M, Bommarco R. Aboveground insect herbivory increases plant competitive asymmetry, while belowground herbivory mitigates the effect. PeerJ 2016; 4:e1867. [PMID: 27069805 PMCID: PMC4824911 DOI: 10.7717/peerj.1867] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/09/2016] [Indexed: 11/22/2022] Open
Abstract
Insect herbivores can shift the composition of a plant community, but the mechanism underlying such shifts remains largely unexplored. A possibility is that insects alter the competitive symmetry between plant species. The effect of herbivory on competition likely depends on whether the plants are subjected to aboveground or belowground herbivory or both, and also depends on soil nitrogen levels. It is unclear how these biotic and abiotic factors interactively affect competition. In a greenhouse experiment, we measured competition between two coexisting grass species that respond differently to nitrogen deposition: Dactylis glomerata L., which is competitively favoured by nitrogen addition, and Festuca rubra L., which is competitively favoured on nitrogen-poor soils. We predicted: (1) that aboveground herbivory would reduce competitive asymmetry at high soil nitrogen by reducing the competitive advantage of D. glomerata; and (2), that belowground herbivory would relax competition at low soil nitrogen, by reducing the competitive advantage of F. rubra. Aboveground herbivory caused a 46% decrease in the competitive ability of F. rubra, and a 23% increase in that of D. glomerata, thus increasing competitive asymmetry, independently of soil nitrogen level. Belowground herbivory did not affect competitive symmetry, but the combined influence of above- and belowground herbivory was weaker than predicted from their individual effects. Belowground herbivory thus mitigated the increased competitive asymmetry caused by aboveground herbivory. D. glomerata remained competitively dominant after the cessation of aboveground herbivory, showing that the influence of herbivory continued beyond the feeding period. We showed that insect herbivory can strongly influence plant competitive interactions. In our experimental plant community, aboveground insect herbivory increased the risk of competitive exclusion of F. rubra. Belowground herbivory appeared to mitigate the influence of aboveground herbivory, and this mechanism may play a role for plant species coexistence.
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Affiliation(s)
- Pernilla Borgström
- Department of Ecology, Swedish University of Agricultural Sciences , Uppsala , Sweden
| | - Joachim Strengbom
- Department of Ecology, Swedish University of Agricultural Sciences , Uppsala , Sweden
| | - Maria Viketoft
- Department of Ecology, Swedish University of Agricultural Sciences , Uppsala , Sweden
| | - Riccardo Bommarco
- Department of Ecology, Swedish University of Agricultural Sciences , Uppsala , Sweden
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125
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Abstract
Tree growth, especially diameter growth of tree stems, is an important issue for understanding the productivity and dynamics of forest stands. Metabolic scaling theory predicted that the 2/3 power of stem diameter at a certain time is a linear function of the 2/3 power of the initial diameter and that the diameter growth rate scales to the 1/3 power of the initial diameter. We tested these predictions of the metabolic scaling theory for 11 Japanese secondary forests at various growth stages. The predictions were not supported by the data, especially in younger stands. Alternatively, we proposed a new theoretical model for stem diameter growth on the basis of six assumptions. All these assumptions were supported by the data. The model produced a nearly linear to curvilinear relationship between the 2/3 power of stem diameters at two different times. It also fitted well to the curvilinear relationship between diameter growth rate and the initial diameter. Our model fitted better than the metabolic scaling theory, suggesting the importance of asymmetric competition among trees, which has not been incorporated in the metabolic scaling theory.
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126
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Huber H, During HJ, Bruine de Bruin F, Vermeulen PJ, Anten NPR. Genotypic and Phenotypic Diversity Does Not Affect Productivity and Drought Response in Competitive Stands of Trifolium repens. FRONTIERS IN PLANT SCIENCE 2016; 7:364. [PMID: 27064974 PMCID: PMC4809891 DOI: 10.3389/fpls.2016.00364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/08/2016] [Indexed: 06/05/2023]
Abstract
Clonal plants can form dense canopies in which plants of different genetic origin are competing for the uptake of essential resources. The competitive relationships among these clones are likely to be affected by extreme environmental conditions, such as prolonged drought spells, which are predicted to occur more frequently due to global climate change. This, in turn, may alter characteristics of the ecological system and its associated functioning. We hypothesized that the relative success of individual clones will depend on the size of the ramets as ramets with larger leaves and longer petioles (large ramets) were predicted to have a competitive advantage in terms of increased light interception over smaller-sized ramets. Under drier conditions the relative performances of genotypes were expected to change leading to a change in genotype ranking. We also hypothesized that increased genotypic and phenotypic diversity will increase stand performance and resistance to drought. These hypotheses and the mechanisms responsible for shifts in competitive relationships were investigated by subjecting genotypes of the important pasture legume Trifolium repens to competition with either genetically identical clones, genetically different but similarly sized clones, or genetically as well as morphologically different clones under well-watered and dry conditions. Competitive relationships were affected by ramet size with large genotypes outperforming small genotypes in diverse stands in terms of biomass production. However, large genotypes also produced relatively fewer ramets than small genotypes and could not benefit in terms of clonal reproduction from competing with smaller genotypes, indicating that evolutionary shifts in genotype composition will depend on whether ramet size or ramet number is under selection. In contrast to our hypotheses, diversity did not increase stand performance under different selection regimes and genotype ranking was hardly affected by soil moisture, indicating that increasing fluctuations in water availability result in few short-term effects on genotypic diversity in this stoloniferous grassland species. Communities dominated by stoloniferous herbs such as T. repens may be relatively resilient to environmental change and to low levels of genetic diversity.
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Affiliation(s)
- Heidrun Huber
- Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University Nijmegen Nijmegen, Netherlands
| | - Heinjo J During
- Section of Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University Utrecht, Netherlands
| | - Fabienne Bruine de Bruin
- Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University Nijmegen Nijmegen, Netherlands
| | - Peter J Vermeulen
- Centre for Crop Systems Analysis, Wageningen University Wageningen, Netherlands
| | - Niels P R Anten
- Centre for Crop Systems Analysis, Wageningen University Wageningen, Netherlands
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127
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Hara T, Yokoishi E, Ishiwata M, Kimura M. Canopy tree competition and species coexistence in anAbies veitchiiandA. mariesiimixed subalpine forest, central Japan. ECOSCIENCE 2016. [DOI: 10.1080/11956860.1994.11682248] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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128
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Bourdier T, Cordonnier T, Kunstler G, Piedallu C, Lagarrigues G, Courbaud B. Tree Size Inequality Reduces Forest Productivity: An Analysis Combining Inventory Data for Ten European Species and a Light Competition Model. PLoS One 2016; 11:e0151852. [PMID: 26999820 PMCID: PMC4801349 DOI: 10.1371/journal.pone.0151852] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 03/04/2016] [Indexed: 11/29/2022] Open
Abstract
Plant structural diversity is usually considered as beneficial for ecosystem functioning. For instance, numerous studies have reported positive species diversity-productivity relationships in plant communities. However, other aspects of structural diversity such as individual size inequality have been far less investigated. In forests, tree size inequality impacts directly tree growth and asymmetric competition, but consequences on forest productivity are still indeterminate. In addition, the effect of tree size inequality on productivity is likely to vary with species shade-tolerance, a key ecological characteristic controlling asymmetric competition and light resource acquisition. Using plot data from the French National Geographic Agency, we studied the response of stand productivity to size inequality for ten forest species differing in shade tolerance. We fitted a basal area stand production model that included abiotic factors, stand density, stand development stage and a tree size inequality index. Then, using a forest dynamics model we explored whether mechanisms of light interception and light use efficiency could explain the tree size inequality effect observed for three of the ten species studied. Size inequality negatively affected basal area increment for seven out of the ten species investigated. However, this effect was not related to the shade tolerance of these species. According to the model simulations, the negative tree size inequality effect could result both from reduced total stand light interception and reduced light use efficiency. Our results demonstrate that negative relationships between size inequality and productivity may be the rule in tree populations. The lack of effect of shade tolerance indicates compensatory mechanisms between effect on light availability and response to light availability. Such a pattern deserves further investigations for mixed forests where complementarity effects between species are involved. When studying the effect of structural diversity on ecosystem productivity, tree size inequality is a major facet that should be taken into account.
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Affiliation(s)
- Thomas Bourdier
- Irstea, UR EMGR, Centre de Grenoble, 2 rue de la Papeterie-BP 76, F-38402 Saint-Martin-d’Hères, France
- Univ. Grenoble Alpes, F-38402 Grenoble, France
- * E-mail:
| | - Thomas Cordonnier
- Irstea, UR EMGR, Centre de Grenoble, 2 rue de la Papeterie-BP 76, F-38402 Saint-Martin-d’Hères, France
- Univ. Grenoble Alpes, F-38402 Grenoble, France
| | - Georges Kunstler
- Irstea, UR EMGR, Centre de Grenoble, 2 rue de la Papeterie-BP 76, F-38402 Saint-Martin-d’Hères, France
- Univ. Grenoble Alpes, F-38402 Grenoble, France
| | - Christian Piedallu
- AgroParisTech, UMR1092, Laboratoire d’Étude des Ressources Forêt-Bois (LERFoB), ENGREF, 14 rue Girardet, CS14216, FR- 54042 Nancy Cedex, France
| | - Guillaume Lagarrigues
- Irstea, UR EMGR, Centre de Grenoble, 2 rue de la Papeterie-BP 76, F-38402 Saint-Martin-d’Hères, France
- Univ. Grenoble Alpes, F-38402 Grenoble, France
| | - Benoit Courbaud
- Irstea, UR EMGR, Centre de Grenoble, 2 rue de la Papeterie-BP 76, F-38402 Saint-Martin-d’Hères, France
- Univ. Grenoble Alpes, F-38402 Grenoble, France
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129
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Velázquez J, Allen RB, Coomes DA, Eichhorn MP. Asymmetric competition causes multimodal size distributions in spatially structured populations. Proc Biol Sci 2016; 283:rspb.2015.2404. [PMID: 26817778 DOI: 10.1098/rspb.2015.2404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Plant sizes within populations often exhibit multimodal distributions, even when all individuals are the same age and have experienced identical conditions. To establish the causes of this, we created an individual-based model simulating the growth of trees in a spatially explicit framework, which was parametrized using data from a long-term study of forest stands in New Zealand. First, we demonstrate that asymmetric resource competition is a necessary condition for the formation of multimodal size distributions within cohorts. By contrast, the legacy of small-scale clustering during recruitment is transient and quickly overwhelmed by density-dependent mortality. Complex multi-layered size distributions are generated when established individuals are restricted in the spatial domain within which they can capture resources. The number of modes reveals the effective number of direct competitors, while the separation and spread of modes are influenced by distances among established individuals. Asymmetric competition within local neighbourhoods can therefore generate a range of complex size distributions within even-aged cohorts.
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Affiliation(s)
- Jorge Velázquez
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, UK Facultad de Ciencias Físico Matemáticas, Universidad Autónoma de Puebla, Puebla, Pue. 72001, México
| | - Robert B Allen
- Landcare Research, P.O. Box 69, Lincoln 8152, New Zealand
| | - David A Coomes
- Forest Ecology and Conservation Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| | - Markus P Eichhorn
- School of Life Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
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130
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Bassar RD, Childs DZ, Rees M, Tuljapurkar S, Reznick DN, Coulson T. The effects of asymmetric competition on the life history of Trinidadian guppies. Ecol Lett 2016; 19:268-78. [PMID: 26843397 PMCID: PMC4991285 DOI: 10.1111/ele.12563] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/03/2015] [Accepted: 11/24/2015] [Indexed: 11/28/2022]
Abstract
The effects of asymmetric interactions on population dynamics has been widely investigated, but there has been little work aimed at understanding how life history parameters like generation time, life expectancy and the variance in lifetime reproductive success are impacted by different types of competition. We develop a new framework for incorporating trait‐mediated density‐dependence into size‐structured models and use Trinidadian guppies to show how different types of competitive interactions impact life history parameters. Our results show the degree of symmetry in competitive interactions can have dramatic effects on the speed of the life history. For some vital rates, shifting the competitive superiority from small to large individuals resulted in a doubling of the generation time. Such large influences of competitive symmetry on the timescale of demographic processes, and hence evolution, highlights the interwoven nature of ecological and evolutionary processes and the importance of density‐dependence in understanding eco‐evolutionary dynamics.
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Affiliation(s)
- Ronald D Bassar
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Dylan Z Childs
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Mark Rees
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | | | - David N Reznick
- Department of Biology, University of California, Riverside, CA, USA
| | - Tim Coulson
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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131
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González-Rivero M, Bozec YM, Chollett I, Ferrari R, Schönberg CHL, Mumby PJ. Asymmetric competition prevents the outbreak of an opportunistic species after coral reef degradation. Oecologia 2016; 181:161-73. [DOI: 10.1007/s00442-015-3541-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 12/25/2015] [Indexed: 11/29/2022]
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132
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Lin Y, Berger U, Yue M, Grimm V. Asymmetric facilitation can reduce size inequality in plant populations resulting in delayed density-dependent mortality. OIKOS 2015. [DOI: 10.1111/oik.02593] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yue Lin
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig; Deutscher Platz 5e DE-04103 Leipzig Germany
- Helmholtz Centre for Environmental Research − UFZ; Dept of Ecological Modelling; Permoserstraße 15 DE-04318 Leipzig Germany
- School of Life Science, Northwest University; CN-710069 Xi'an China
| | - Uta Berger
- Inst. of Forest Growth and Computer Science, Technische Universität Dresden; PO 1117, DE-01735 Tharandt Germany
| | - Ming Yue
- School of Life Science, Northwest University; CN-710069 Xi'an China
| | - Volker Grimm
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig; Deutscher Platz 5e DE-04103 Leipzig Germany
- Helmholtz Centre for Environmental Research − UFZ; Dept of Ecological Modelling; Permoserstraße 15 DE-04318 Leipzig Germany
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133
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Lübbe T, Schuldt B, Leuschner C. Species identity and neighbor size surpass the impact of tree species diversity on productivity in experimental broad-leaved tree sapling assemblages under dry and moist conditions. FRONTIERS IN PLANT SCIENCE 2015; 6:857. [PMID: 26579136 PMCID: PMC4620412 DOI: 10.3389/fpls.2015.00857] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 09/28/2015] [Indexed: 05/22/2023]
Abstract
Species diversity may increase the productivity of tree communities through complementarity (CE) and/or selection effects (SE), but it is not well known how this relationship changes under water limitation. We tested the stress-gradient hypothesis, which predicts that resource use complementarity and facilitation are more important under water-limited conditions. We conducted a growth experiment with saplings of five temperate broad-leaved tree species that were grown in assemblages of variable diversity (1, 3, or 5 species) and species composition under ample and limited water supply to examine effects of species richness and species identity on stand- and tree-level productivity. Special attention was paid to effects of neighbor identity on the growth of target trees in mixture as compared to growth in monoculture. Stand productivity was strongly influenced by species identity while a net biodiversity effect (NE) was significant in the moist treatment (mostly assignable to CE) but of minor importance. The growth performance of some of the species in the mixtures was affected by tree neighborhood characteristics with neighbor size likely being more important than neighbor species identity. Diversity and neighbor identity effects visible in the moist treatment mostly disappeared in the dry treatment, disproving the stress-gradient hypothesis. The mixtures were similarly sensitive to drought-induced growth reduction as the monocultures, which may relate to the decreased CE on growth upon drought in the mixtures.
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Affiliation(s)
- Torben Lübbe
- Plant Ecology and Ecosystems Research, Albrecht von Haller Institute for Plant Sciences, University of GöttingenGöttingen, Germany
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134
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Trouvé R, Bontemps JD, Seynave I, Collet C, Lebourgeois F. Stand density, tree social status and water stress influence allocation in height and diameter growth of Quercus petraea (Liebl.). TREE PHYSIOLOGY 2015; 35:1035-46. [PMID: 26232785 DOI: 10.1093/treephys/tpv067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 06/22/2015] [Indexed: 05/21/2023]
Abstract
Even-aged forest stands are competitive communities where competition for light gives advantages to tall individuals, thereby inducing a race for height. These same individuals must however balance this competitive advantage with height-related mechanical and hydraulic risks. These phenomena may induce variations in height-diameter growth relationships, with primary dependences on stand density and tree social status as proxies for competition pressure and access to light, and on availability of local environmental resources, including water. We aimed to investigate the effects of stand density, tree social status and water stress on the individual height-circumference growth allocation (Δh-Δc), in even-aged stands of Quercus petraea Liebl. (sessile oak). Within-stand Δc was used as surrogate for tree social status. We used an original long-term experimental plot network, set up in the species production area in France, and designed to explore stand dynamics on a maximum density gradient. Growth allocation was modelled statistically by relating the shape of the Δh-Δc relationship to stand density, stand age and water deficit. The shape of the Δh-Δc relationship shifted from linear with a moderate slope in open-grown stands to concave saturating with an initial steep slope in closed stands. Maximum height growth was found to follow a typical mono-modal response to stand age. In open-grown stands, increasing summer soil water deficit was found to decrease height growth relative to radial growth, suggesting hydraulic constraints on height growth. A similar pattern was found in closed stands, the magnitude of the effect however lowering from suppressed to dominant trees. We highlight the high phenotypic plasticity of growth in sessile oak trees that further adapt their allocation scheme to their environment. Stand density and tree social status were major drivers of growth allocation variations, while water stress had a detrimental effect on height in the Δh-Δc allocation.
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Affiliation(s)
- Raphaël Trouvé
- AgroParisTech, Centre de Nancy, UMR 1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 14 rue Girardet, 54000 Nancy, France INRA, Centre de Nancy-Lorraine, UMR1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 54280 Champenoux, France
| | - Jean-Daniel Bontemps
- AgroParisTech, Centre de Nancy, UMR 1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 14 rue Girardet, 54000 Nancy, France INRA, Centre de Nancy-Lorraine, UMR1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 54280 Champenoux, France
| | - Ingrid Seynave
- AgroParisTech, Centre de Nancy, UMR 1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 14 rue Girardet, 54000 Nancy, France INRA, Centre de Nancy-Lorraine, UMR1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 54280 Champenoux, France
| | - Catherine Collet
- AgroParisTech, Centre de Nancy, UMR 1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 14 rue Girardet, 54000 Nancy, France INRA, Centre de Nancy-Lorraine, UMR1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 54280 Champenoux, France
| | - François Lebourgeois
- AgroParisTech, Centre de Nancy, UMR 1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 14 rue Girardet, 54000 Nancy, France INRA, Centre de Nancy-Lorraine, UMR1092 INRA/AgroParisTech Laboratoire d'Étude des Ressources Forêt Bois (LERFoB), 54280 Champenoux, France
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135
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Golan G, Oksenberg A, Peleg Z. Genetic evidence for differential selection of grain and embryo weight during wheat evolution under domestication. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:5703-11. [PMID: 26019253 PMCID: PMC4566971 DOI: 10.1093/jxb/erv249] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Wheat is one of the Neolithic founder crops domesticated ~10 500 years ago. Following the domestication episode, its evolution under domestication has resulted in various genetic modifications. Grain weight, embryo weight, and the interaction between those factors were examined among domesticated durum wheat and its direct progenitor, wild emmer wheat. Experimental data show that grain weight has increased over the course of wheat evolution without any parallel change in embryo weight, resulting in a significantly reduced (30%) embryo weight/grain weight ratio in domesticated wheat. The genetic factors associated with these modifications were further investigated using a population of recombinant inbred substitution lines that segregated for chromosome 2A. A cluster of loci affecting grain weight and shape was identified on the long arm of chromosome 2AL. Interestingly, a novel locus controlling embryo weight was mapped on chromosome 2AS, on which the wild emmer allele promotes heavier embryos and greater seedling vigour. To the best of our knowledge, this is the first report of a QTL for embryo weight in wheat. The results suggest a differential selection of grain and embryo weight during the evolution of domesticated wheat. It is argued that conscious selection by early farmers favouring larger grains and smaller embryos appears to have resulted in a significant change in endosperm weight/embryo weight ratio in the domesticated wheat. Exposing the genetic factors associated with endosperm and embryo size improves our understanding of the evolutionary dynamics of wheat under domestication and is likely to be useful for future wheat-breeding efforts.
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Affiliation(s)
- Guy Golan
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Adi Oksenberg
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Zvi Peleg
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
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136
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Abstract
Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner’s Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games. Biological interactions, even between members of the same species, are almost always asymmetric due to differences in size, access to resources, or past interactions. However, classical game-theoretical models of evolution fail to account for sources of asymmetry in a comprehensive manner. Here, we extend the theory of evolutionary games to two general classes of asymmetry arising from environmental variation and individual differences, covering much of the heterogeneity observed in nature. If selection is weak, evolutionary processes based on asymmetric interactions behave macroscopically like symmetric games with payoffs that may depend on the resource distribution in the population or its structure. Asymmetry uncovers differences between genetic and cultural evolution that are not apparent when interactions are symmetric.
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137
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Hansen NCK, Avershina E, Mydland LT, Næsset JA, Austbø D, Moen B, Måge I, Rudi K. High nutrient availability reduces the diversity and stability of the equine caecal microbiota. MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2015; 26:27216. [PMID: 26246403 PMCID: PMC4526772 DOI: 10.3402/mehd.v26.27216] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 06/18/2015] [Accepted: 07/03/2015] [Indexed: 11/14/2022]
Abstract
BACKGROUND It is well known that nutrient availability can alter the gut microbiota composition, while the effect on diversity and temporal stability remains largely unknown. METHODS Here we address the equine caecal microbiota temporal stability, diversity, and functionality in response to diets with different levels of nutrient availability. Hay (low and slower nutrient availability) versus a mixture of hay and whole oats (high and more rapid nutrient availability) were used as experimental diets. RESULTS We found major effects on the microbiota despite that the caecal pH was far from sub-clinical acidosis. We found that the low nutrient availability diet was associated with a higher level of both diversity and temporal stability of the caecal microbiota than the high nutrient availability diet. These observations concur with general ecological theories, suggesting a stabilising effect of biological diversity and that high nutrient availability has a destabilising effect through reduced diversity. CONCLUSION Nutrient availability does not only change the composition but also the ecology of the caecal microbiota.
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Affiliation(s)
- Naja C K Hansen
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Aas, Norway
| | - Ekaterina Avershina
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Liv T Mydland
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Aas, Norway
| | - Jon A Næsset
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Aas, Norway
| | - Dag Austbø
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Aas, Norway
| | - Birgitte Moen
- Nofima, The Norwegian Institute of Food, Fisheries and Aquaculture Research, Aas, Norway
| | - Ingrid Måge
- Nofima, The Norwegian Institute of Food, Fisheries and Aquaculture Research, Aas, Norway
| | - Knut Rudi
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway;
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138
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Takahashi K, Aoki K. Effects of climatic conditions on annual shoot length and tree-ring width of alpine dwarf pine Pinus pumila in central Japan. JOURNAL OF PLANT RESEARCH 2015; 128:553-562. [PMID: 25841333 DOI: 10.1007/s10265-015-0723-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 01/14/2015] [Indexed: 06/04/2023]
Abstract
This study compared the effects of climatic conditions on annual shoot length (ASL) and tree-ring width (TRW) of alpine dwarf pine Pinus pumila in central Japan, by using dendrochronological techniques. Chronologies of ASL (1951-2009) and TRW (1972-2009) were standardized to remove non-climatic signals, and correlation tests were done for non-standardized observed values and standardized indices with monthly temperatures and precipitation. Monthly mean temperatures from March to October, except for July, increased during 1951‒2009; observed values and a standardized index of ASL increased during this period. For the rate of increase in ASL, the standardized index was lower than the observed values. However, these values of TRW showed no trends. The observed values and standardized index of TRW positively correlated with temperatures of the beginning of the growing season of the current year. The observed values of ASL positively correlated with temperatures during the growing season of the previous and current years. However, the standardized index of ASL positively correlated with only June temperatures of the previous and current years. The different results of ASL between observed values and standardized indices indicate that many significant correlations of observed values were attributable to increasing trends of temperature and ASL. This study suggests that standardized ASL of P. pumila tended to increase greater than TRW, that high temperatures at the beginning of the growing season increases ASL and TRW, and that analyzing observed values of ASL may overestimate the effects of temperature on ASL of P. pumila.
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Affiliation(s)
- Koichi Takahashi
- Department of Biology, Faculty of Science, Shinshu University, Asahi 3-1-1, Matsumoto, 390-8621, Japan,
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139
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Nonlinear Simultaneous Equations for Individual-Tree Diameter Growth and Mortality Model of Natural Mongolian Oak Forests in Northeast China. FORESTS 2015. [DOI: 10.3390/f6062261] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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140
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Anderson TL, Whiteman HH. Asymmetric effects of intra- and interspecific competition on a pond-breeding salamander. Ecology 2015. [DOI: 10.1890/14-0479.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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141
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Kost MA, Alexander HM, Jason Emry D, Mercer KL. Life history traits and phenotypic selection among sunflower crop-wild hybrids and their wild counterpart: implications for crop allele introgression. Evol Appl 2015; 8:510-24. [PMID: 26029263 PMCID: PMC4430773 DOI: 10.1111/eva.12261] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 03/18/2015] [Indexed: 12/01/2022] Open
Abstract
Hybridization produces strong evolutionary forces. In hybrid zones, selection can differentially occur on traits and selection intensities may differ among hybrid generations. Understanding these dynamics in crop-wild hybrid zones can clarify crop-like traits likely to introgress into wild populations and the particular hybrid generations through which introgression proceeds. In a field experiment with four crop-wild hybrid Helianthus annuus (sunflower) cross types, we measured growth and life history traits and performed phenotypic selection analysis on early season traits to ascertain the likelihood, and routes, of crop allele introgression into wild sunflower populations. All cross types overwintered, emerged in the spring, and survived until flowering, indicating no early life history barriers to crop allele introgression. While selection indirectly favored earlier seedling emergence and taller early season seedlings, direct selection only favored greater early season leaf length. Further, there was cross type variation in the intensity of selection operating on leaf length. Thus, introgression of multiple early season crop-like traits, due to direct selection for greater early season leaf length, should not be impeded by any cross type and may proceed at different rates among generations. In sum, alleles underlying early season sunflower crop-like traits are likely to introgress into wild sunflower populations.
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Affiliation(s)
- Matthew A Kost
- Department of Horticulture and Crop Science, The Ohio State UniversityWooster, OH, USA
| | - Helen M Alexander
- Department of Ecology and Evolutionary Biology, University of KansasLawrence, KS, USA
| | - D Jason Emry
- Department of Ecology and Evolutionary Biology, University of KansasLawrence, KS, USA
- Department of Biology, Washburn UniversityTopeka, KS, USA
| | - Kristin L Mercer
- Department of Horticulture and Crop Science, The Ohio State UniversityColumbus, OH, USA
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142
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Nakagawa Y, Yokozawa M, Hara T. Competition among plants can lead to an increase in aggregation of smaller plants around larger ones. Ecol Modell 2015. [DOI: 10.1016/j.ecolmodel.2015.01.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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143
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Gross N, Liancourt P, Butters R, Duncan RP, Hulme PE. Functional equivalence, competitive hierarchy and facilitation determine species coexistence in highly invaded grasslands. THE NEW PHYTOLOGIST 2015; 206:175-186. [PMID: 25388949 DOI: 10.1111/nph.13168] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 10/13/2014] [Indexed: 06/04/2023]
Abstract
Alien and native plant species often differ in functional traits. Trait differences could lead to niche differences that minimize competitive interactions and stabilize coexistence. However, trait differences could also translate into average fitness differences, leading to a competitive hierarchy that prevents coexistence. We tested whether trait differences between alien and native species translated into average fitness or stabilizing niche differences, and whether competition could explain observed coexistence within invaded grassland communities (New Zealand). Trait differences reflected marked competitive hierarchy, suggesting average fitness differences. Species coexistence was determined by a trade-off between species susceptibility to herbivory vs competitive hierarchy and facilitation. Importantly, although aliens and natives differed in their trait values, they did not differ in their competitive response, highlighting the importance of equalizing mechanisms in structuring invaded communities. Only a few alien species with a particular set of traits were able to jeopardize species coexistence when grazing was ceased. Our study explains why some alien species coexist with natives, whereas others have strong impacts on native communities. It highlights that trait differences can underlie several coexistence processes and that the demonstration of trait differences between aliens and natives is only a first step to understanding the role of biotic interactions in structuring invaded communities.
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Affiliation(s)
- Nicolas Gross
- INRA, USC1339 Chizé (CEBC), 79360, Villiers-en-Bois, France
- Centre d'étude Biologique de Chizé, CNRS - Université La Rochelle (UMR 7372), 79360, Villiers-en-Bois, France
- Bio-Protection Research Centre, Lincoln University 7647, PO Box 84, Canterbury, New Zealand
| | - Pierre Liancourt
- Institute of Botany, Academy of Sciences of the Czech Republic, Třeboň, 37982, Czech Republic
| | - Robyn Butters
- Bio-Protection Research Centre, Lincoln University 7647, PO Box 84, Canterbury, New Zealand
| | - Richard P Duncan
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia
| | - Philip E Hulme
- Bio-Protection Research Centre, Lincoln University 7647, PO Box 84, Canterbury, New Zealand
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144
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Commensal pathogens as a source of a coexistence mechanism. J Theor Biol 2015; 370:45-52. [DOI: 10.1016/j.jtbi.2015.01.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 01/19/2015] [Accepted: 01/25/2015] [Indexed: 11/17/2022]
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145
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Siebenkäs A, Schumacher J, Roscher C. Phenotypic plasticity to light and nutrient availability alters functional trait ranking across eight perennial grassland species. AOB PLANTS 2015; 7:plv029. [PMID: 25818071 PMCID: PMC4417138 DOI: 10.1093/aobpla/plv029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/13/2015] [Indexed: 05/28/2023]
Abstract
Functional traits are often used as species-specific mean trait values in comparative plant ecology or trait-based predictions of ecosystem processes, assuming that interspecific differences are greater than intraspecific trait variation and that trait-based ranking of species is consistent across environments. Although this assumption is increasingly challenged, there is a lack of knowledge regarding to what degree the extent of intraspecific trait variation in response to varying environmental conditions depends on the considered traits and the characteristics of the studied species to evaluate the consequences for trait-based species ranking. We studied functional traits of eight perennial grassland species classified into different functional groups (forbs vs. grasses) and varying in their inherent growth stature (tall vs. small) in a common garden experiment with different environments crossing three levels of nutrient availability and three levels of light availability over 4 months of treatment applications. Grasses and forbs differed in almost all above- and belowground traits, while trait differences related to growth stature were generally small. The traits showing the strongest responses to resource availability were similarly for grasses and forbs those associated with allocation and resource uptake. The strength of trait variation in response to varying resource availability differed among functional groups (grasses > forbs) and species of varying growth stature (small-statured > tall-statured species) in many aboveground traits, but only to a lower extent in belowground traits. These differential responses altered trait-based species ranking in many aboveground traits, such as specific leaf area, tissue nitrogen and carbon concentrations and above-belowground allocation (leaf area ratio and root : shoot ratio) at varying resource supply, while trait-based species ranking was more consistent in belowground traits. Our study shows that species grouping according to functional traits is valid, but trait-based species ranking depends on environmental conditions, thus limiting the applicability of species-specific mean trait values in ecological studies.
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Affiliation(s)
- Alrun Siebenkäs
- Department of Community Ecology, Helmholtz Centre for Environmental Research -UFZ, Theodor-Lieser-Straße 4, 06120 Halle, Germany
| | - Jens Schumacher
- Institute of Stochastics, Friedrich Schiller University Jena, Ernst-Abbe-Platz 2, 07743 Jena, Germany
| | - Christiane Roscher
- Department of Community Ecology, Helmholtz Centre for Environmental Research -UFZ, Theodor-Lieser-Straße 4, 06120 Halle, Germany
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146
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Fichtner A, Forrester DI, Härdtle W, Sturm K, von Oheimb G. Facilitative-competitive interactions in an old-growth forest: the importance of large-diameter trees as benefactors and stimulators for forest community assembly. PLoS One 2015; 10:e0120335. [PMID: 25803035 PMCID: PMC4372556 DOI: 10.1371/journal.pone.0120335] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 01/26/2015] [Indexed: 11/26/2022] Open
Abstract
The role of competition in tree communities is increasingly well understood, while little is known about the patterns and mechanisms of the interplay between above- and belowground competition in tree communities. This knowledge, however, is crucial for a better understanding of community dynamics and developing adaptive near-natural management strategies. We assessed neighbourhood interactions in an unmanaged old-growth European beech (Fagus sylvatica) forest by quantifying variation in the intensity of above- (shading) and belowground competition (crowding) among dominant and co-dominant canopy beech trees during tree maturation. Shading had on average a much larger impact on radial growth than crowding and the sensitivity to changes in competitive conditions was lowest for crowding effects. We found that each mode of competition reduced the effect of the other. Increasing crowding reduced the negative effect of shading, and at high levels of shading, crowding actually had a facilitative effect and increased growth. Our study demonstrates that complementarity in above- and belowground processes enable F. sylvatica to alter resource acquisition strategies, thus optimising tree radial growth. As a result, competition seemed to become less important in stands with a high growing stock and tree communities with a long continuity of anthropogenic undisturbed population dynamics. We suggest that growth rates do not exclusively depend on the density of potential competitors at the intraspecific level, but on the conspecific aggregation of large-diameter trees and their functional role for regulating biotic filtering processes. This finding highlights the potential importance of the rarely examined relationship between the spatial aggregation pattern of large-diameter trees and the outcome of neighbourhood interactions, which may be central to community dynamics and the related forest ecosystem services.
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Affiliation(s)
- Andreas Fichtner
- Institute of Ecology, Leuphana University of Lüneburg, Lüneburg, Germany
| | | | - Werner Härdtle
- Institute of Ecology, Leuphana University of Lüneburg, Lüneburg, Germany
| | - Knut Sturm
- Community Forest Lübeck, Lübeck, Germany
| | - Goddert von Oheimb
- Institute of General Ecology and Environmental Protection, Technische Universität Dresden, Tharandt, Germany
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147
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Local density effects on individual production are dynamic: insights from natural stands of a perennial savanna grass. Oecologia 2015; 178:1125-35. [DOI: 10.1007/s00442-015-3291-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 03/05/2015] [Indexed: 11/26/2022]
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148
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Ben-Hur E, Kadmon R. An experimental test of the relationship between seed size and competitive ability in annual plants. OIKOS 2015. [DOI: 10.1111/oik.02111] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Eyal Ben-Hur
- Dept of Ecology, Evolution and Behavior; Inst. of Life Sciences, The Hebrew Univ. of Jerusalem; 91904, Campus Edmond J. Safra, Givat-Ram IL-91906 Jerusalem Israel
| | - Ronen Kadmon
- Dept of Ecology, Evolution and Behavior; Inst. of Life Sciences, The Hebrew Univ. of Jerusalem; 91904, Campus Edmond J. Safra, Givat-Ram IL-91906 Jerusalem Israel
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149
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Plant trait expression responds to establishment timing. Oecologia 2015; 178:525-36. [DOI: 10.1007/s00442-014-3216-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 12/31/2014] [Indexed: 10/24/2022]
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150
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