共查询到20条相似文献,搜索用时 15 毫秒
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We studied the effects of hand weeding of second‐year plants of the biennial garlic mustard (Alliaria petiolata) on first‐year plants (seedlings) and native ground layer vegetation. Garlic mustard is a Eurasian species that has invaded deciduous forest ground layers in eastern North America. Treatments consisted of a control and an early or late weeding of second‐year garlic mustard. The early treatment (early March) was applied before garlic mustard seeds had germinated and when most native species were dormant. The late treatment (mid‐May) occurred after plants had bolted, flowering was occurring, and most native species and new garlic mustard seedlings were actively growing. Pre‐treatment data were obtained in 2004 and treated and control plots were sampled in 2005, 2006, and 2007. No significant treatment effects were observed in 2004 or 2005. In 2006, mean cover of first‐year plants was higher in the early weeding treatment than in the late weeding treatment and control. In 2007, mean cover of first‐year garlic mustard was higher in the control than in either of the two weeding treatments. There were no significant treatment effects in any year on native vegetation cover, bare ground, or the five most abundant native species. Our data indicate that (1) late weeding of garlic mustard provided more effective control than early weeding because late weeding allows second‐year plants to compete with garlic mustard seedlings for a longer period of time and (2) competition between first‐ and second‐year plants is responsible for alternating dominance of first‐year and second‐year garlic mustard plants. 相似文献
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Yang Chen Tao Ma Lushui Zhang Minghui Kang Zhiyang Zhang Zeyu Zheng Pengchuan Sun Nawal Shrestha Jianquan Liu Yongzhi Yang 《Molecular ecology resources》2020,20(3):756-769
Davidia involucrata Baill, also known as the dove‐tree, is a living fossil and an endangered species currently restricted to the mountains of southwestern and central China. It has a beautiful and innovative trait of high horticultural value: two white bracts covering the flower caputila. Here, we report on the chromosome‐scale genome of this species using single‐molecule real‐time long reads and chromosome conformation capture (Hi‐C) techniques. This species has a larger genome size of 1,169 Mb and contains relatively more genes (42,554) than the closely related species Camptotheca acuminata (397 Mb and 31,825 genes). Both species shared one recent whole genome duplication before their divergence. The expansion of the repetitive elements after their divergence contributed greatly to the increase in the genome size of the dove‐tree. Photosynthesis‐related genes were almost absent or showed reduced expression in the bracts of the dove‐tree, while defence‐ and chemical‐related genes increased greatly, highlighting the important roles of the bracts in protecting flowers and attracting pollinators. The effective population size of the dove‐tree continuously decreased during the climate changes of the Quaternary. Such climate sensitivity should be fully considered in conservation efforts for this relict endangered species in the context of continuous climate warming in the future. 相似文献
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Sensitivity of community‐level trait–environment relationships to data representativeness: A test for functional biogeography 下载免费PDF全文
Benjamin Borgy Cyrille Violle Philippe Choler Eric Garnier Jens Kattge Jessy Loranger Bernard Amiaud Pierre Cellier Guilhem Debarros Pierre Denelle Sylvain Diquelou Sophie Gachet Claudy Jolivet Sandra Lavorel Servane Lemauviel‐Lavenant Alexis Mikolajczak François Munoz Jean Olivier Nicolas Viovy 《Global Ecology and Biogeography》2017,26(6):729-739
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Estimation of the bacteriocin ColE7 conjugation‐based “kill” – “anti‐kill” antimicrobial system by real‐time PCR,fluorescence staining and bioluminescence assays 下载免费PDF全文
I.L. Maslennikova M.V. Kuznetsova N. Toplak I.V. Nekrasova D. Žgur Bertok M. Starčič Erjavec 《Letters in applied microbiology》2018,67(1):47-53
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A trait‐based trade‐off between growth and mortality: evidence from 15 tropical tree species using size‐specific relative growth rates 下载免费PDF全文
Christopher D. Philipson Daisy H. Dent Michael J. O'Brien Juliette Chamagne Dzaeman Dzulkifli Reuben Nilus Sam Philips Glen Reynolds Philippe Saner Andy Hector 《Ecology and evolution》2014,4(18):3675-3688
A life‐history trade‐off between low mortality in the dark and rapid growth in the light is one of the most widely accepted mechanisms underlying plant ecological strategies in tropical forests. Differences in plant functional traits are thought to underlie these distinct ecological strategies; however, very few studies have shown relationships between functional traits and demographic rates within a functional group. We present 8 years of growth and mortality data from saplings of 15 species of Dipterocarpaceae planted into logged‐over forest in Malaysian Borneo, and the relationships between these demographic rates and four key functional traits: wood density, specific leaf area (SLA), seed mass, and leaf C:N ratio. Species‐specific differences in growth rates were separated from seedling size effects by fitting nonlinear mixed‐effects models, to repeated measurements taken on individuals at multiple time points. Mortality data were analyzed using binary logistic regressions in a mixed‐effects models framework. Growth increased and mortality decreased with increasing light availability. Species differed in both their growth and mortality rates, yet there was little evidence for a statistical interaction between species and light for either response. There was a positive relationship between growth rate and the predicted probability of mortality regardless of light environment, suggesting that this relationship may be driven by a general trade‐off between traits that maximize growth and traits that minimize mortality, rather than through differential species responses to light. Our results indicate that wood density is an important trait that indicates both the ability of species to grow and resistance to mortality, but no other trait was correlated with either growth or mortality. Therefore, the growth mortality trade‐off among species of dipterocarp appears to be general in being independent of species crossovers in performance in different light environments. 相似文献
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Intraspecific variability in the “vowel”‐like sounds of beluga whales (Delphinapterus leucas): Intra‐ and interpopulation comparisons 下载免费PDF全文
Elena M. Panova Roman A. Belikov Alexandr V. Agafonov Olga I. Kirillova Anton D. Chernetsky Vsevolod M. Bel'kovich 《Marine Mammal Science》2016,32(2):452-465
The beluga whale (Delphinapterus leucas) has a rich and complicated vocal repertoire. However, different populations use similar and common types of signals. We studied physical features of one of these types, “vowels,” in three Russian populations: the White Sea population (European North), the Chukotka population (the Bering Sea, Chukotka), and the Okhotsk Sea population (Russian Far East) as well as in four summer aggregations of the White Sea belugas over several years in duration. The pulse repetition rate (PRR) at half of the duration of the signal was measured. We found that the PRR of “vowels” collected in the same summer aggregation during different years is stable in time but varies between locations. The degree of variation corresponds with the geographic distance between different locations. Significant differences were discovered between populations separated by thousands of kilometers, and to a lesser extent, between summer aggregations inhabiting different bays of the White Sea. The variation in PRR between the locations can be caused by the divergence of signals owing to the accumulation of random errors during transmission of these signals from generation to generation, which progressed independently in different summer aggregations and populations. 相似文献
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A global meta‐analysis of the relative extent of intraspecific trait variation in plant communities 下载免费PDF全文
Andrew Siefert Cyrille Violle Loïc Chalmandrier Cécile H. Albert Adrien Taudiere Alex Fajardo Lonnie W. Aarssen Christopher Baraloto Marcos B. Carlucci Marcus V. Cianciaruso Vinícius de L. Dantas Francesco de Bello Leandro D. S. Duarte Carlos R. Fonseca Grégoire T. Freschet Stéphanie Gaucherand Nicolas Gross Kouki Hikosaka Benjamin Jackson Vincent Jung Chiho Kamiyama Masatoshi Katabuchi Steven W. Kembel Emilie Kichenin Nathan J. B. Kraft Anna Lagerström Yoann Le Bagousse‐Pinguet Yuanzhi Li Norman Mason Julie Messier Tohru Nakashizuka Jacob McC. Overton Duane A. Peltzer I. M. Pérez‐Ramos Valério D. Pillar Honor C. Prentice Sarah Richardson Takehiro Sasaki Brandon S. Schamp Christian Schöb Bill Shipley Maja Sundqvist Martin T. Sykes Marie Vandewalle David A. Wardle 《Ecology letters》2015,18(12):1406-1419
Recent studies have shown that accounting for intraspecific trait variation (ITV) may better address major questions in community ecology. However, a general picture of the relative extent of ITV compared to interspecific trait variation in plant communities is still missing. Here, we conducted a meta‐analysis of the relative extent of ITV within and among plant communities worldwide, using a data set encompassing 629 communities (plots) and 36 functional traits. Overall, ITV accounted for 25% of the total trait variation within communities and 32% of the total trait variation among communities on average. The relative extent of ITV tended to be greater for whole‐plant (e.g. plant height) vs. organ‐level traits and for leaf chemical (e.g. leaf N and P concentration) vs. leaf morphological (e.g. leaf area and thickness) traits. The relative amount of ITV decreased with increasing species richness and spatial extent, but did not vary with plant growth form or climate. These results highlight global patterns in the relative importance of ITV in plant communities, providing practical guidelines for when researchers should include ITV in trait‐based community and ecosystem studies. 相似文献
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Invasive bigheaded carp species (Hypophthalmichthys spp.) from Asia have experienced rapid range expansion and population explosions in rivers of the United States resulting in ecosystem damage currently being witnessed and documented by fishery biologists. In addition, silver carp (H. molitrix) present a danger of injury and death to unsuspecting boaters, water skiers or recreational fishers due to their propensity to jump in response to boat motor noise. Fishing‐down bigheaded carp populations for human consumption will reduce environmental damage and potential human injury and mortality until other control measures become available. The name “carp” conveys an extremely negative brand name for purposes of product marketing. We suggest that the silver carp be renamed by the professional scientific community to silverfin (a trademarked name currently used in culinary circles) and the bighead carp (H. nobilis) to bighead. The suggested common names changes represent a simple, albeit small step to reducing bigheaded carp population numbers based on sound product naming strategies developed and used in marketing science. 相似文献
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The “three‐in‐one” formulation of bismuth quadruple therapy for Helicobacter pylori eradication with or without probiotics supplementation: Efficacy and safety in daily clinical practice 下载免费PDF全文
Rocco Maurizio Zagari Alessandra Romiti Enzo Ierardi Antonietta G. Gravina Alba Panarese Giuseppe Grande Edoardo Savarino Giovanni Maconi Elisa Stasi Leonardo Henry Eusebi Fabio Farinati Rita Conigliaro Franco Bazzoli Marco Romano 《Helicobacter》2018,23(4)
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A metagenomics‐based approach to the top‐down effect on the detritivore food web: a salamanders influence on fungal communities within a deciduous forest 下载免费PDF全文
Donald M. Walker Brandy R. Lawrence Dakota Esterline Sean P. Graham Michael A. Edelbrock Jessica A. Wooten 《Ecology and evolution》2014,4(21):4106-4116
The flow of energy within an ecosystem can be considered either top‐down, where predators influence consumers, or bottom‐up, where producers influence consumers. Plethodon cinereus (Red‐backed Salamander) is a terrestrial keystone predator who feeds on invertebrates within the ecosystem. We investigated the impact of the removal of P. cinereus on the detritivore food web in an upland deciduous forest in northwest Ohio, U.S.A. A total of eight aluminum enclosures, each containing a single P. cinereus under a small log, were constructed in the deciduous forest. On Day 1 of the experiment, four salamanders were evicted from four of the eight enclosures. Organic matter and soil were collected from the center of each enclosure at Day 1 and Day 21. From each sample, DNA was extracted, fungal‐specific amplification performed, and 454 pyrosequencing was used to sequence the nuclear ribosomal internal transcribed spacer (ITS2) region and partial ribosomal large subunit (LSU). Changes in overall fungal community composition or species diversity were not statistically significant between treatments. Statistically significant shifts in the most abundant taxonomic groups of fungi were documented in presence but not absence enclosures. We concluded that P. cinereus does not affect the overall composition or diversity of fungal communities, but does have an impact on specific groups of fungi. This study used a metagenomics‐based approach to investigate a missing link among a keystone predator, P. cinereus, invertebrates, and fungal communities, all of which are critical in the detritivore food web. 相似文献
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Jitendra Bhosale Umesh Fegade Banashree Bondhopadhyay Simanpreet Kaur Narinder Singh Anupam Basu Rajesh Dabur Ratnamala Bendre Anil Kuwar 《Journal of molecular recognition : JMR》2015,28(6):369-375
Cation sensing behaviour of a pyrrole‐based derivative (2‐hydroxyl 3 methyl 6 isopropyl benzaldehyde}‐3,4‐dimethyl‐1H‐pyrrole‐2‐carbohydrazide (receptor 3) has been explored and is found to be selective towards Zn2+ over a variety of tested cations. The receptor 3 has shown high selectivity and sensitivity towards Zn2+ over the other alkali, alkaline earth and transition metal ions. In the presence of Zn2+, absorption band of receptor 3 has shown the red shift. The sensing behaviour has been suggested to continue via enhancement process which has further been supported by UV‐vis absorption and theoretical density functional theory (DFT) calculations indicating the formation of a 1:1 complex between the pyrrole based receptor 3 and Zn2+. The present work is presenting a highly selective dual channel colorimetric sensor for zinc with great sensitivity. The developed sensor was successfully applied to image intracellular Zn2+ in living cells. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Fish biogeography in the “Lost World” of the Guiana Shield: Phylogeography of the weakly electric knifefish Gymnotus carapo (Teleostei: Gymnotidae) 下载免费PDF全文
Emma S. Lehmberg Ahmed A. Elbassiouny Devin D. Bloom Hernán López‐Fernández William G.R. Crampton Nathan R. Lovejoy 《Journal of Biogeography》2018,45(4):815-825