Base de dados : MEDLINE
Pesquisa : B01.650.940.800.575.912.250.822.077 [Categoria DeCS]
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  1 / 148 MEDLINE  
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[PMID]:29016604
[Au] Autor:Malmstrom CM; Butterfield HS; Planck L; Long CW; Eviner VT
[Ad] Endereço:Department of Plant Biology, Michigan State University, East Lansing, Michigan, United States of America.
[Ti] Título:Novel fine-scale aerial mapping approach quantifies grassland weed cover dynamics and response to management.
[So] Source:PLoS One;12(10):e0181665, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Invasive weeds threaten the biodiversity and forage productivity of grasslands worldwide. However, management of these weeds is constrained by the practical difficulty of detecting small-scale infestations across large landscapes and by limits in understanding of landscape-scale invasion dynamics, including mechanisms that enable patches to expand, contract, or remain stable. While high-end hyperspectral remote sensing systems can effectively map vegetation cover, these systems are currently too costly and limited in availability for most land managers. We demonstrate application of a more accessible and cost-effective remote sensing approach, based on simple aerial imagery, for quantifying weed cover dynamics over time. In California annual grasslands, the target communities of interest include invasive weedy grasses (Aegilops triuncialis and Elymus caput-medusae) and desirable forage grass species (primarily Avena spp. and Bromus spp.). Detecting invasion of annual grasses into an annual-dominated community is particularly challenging, but we were able to consistently characterize these two communities based on their phenological differences in peak growth and senescence using maximum likelihood supervised classification of imagery acquired twice per year (in mid- and end-of season). This approach permitted us to map weed-dominated cover at a 1-m scale (correctly detecting 93% of weed patches across the landscape) and to evaluate weed cover change over time. We found that weed cover was more pervasive and persistent in management units that had no significant grazing for several years than in those that were grazed, whereas forage cover was more abundant and stable in the grazed units. This application demonstrates the power of this method for assessing fine-scale vegetation transitions across heterogeneous landscapes. It thus provides means for small-scale early detection of invasive species and for testing fundamental questions about landscape dynamics.
[Mh] Termos MeSH primário: Ecossistema
Pradaria
Espécies Introduzidas
Plantas Daninhas/fisiologia
[Mh] Termos MeSH secundário: Biodiversidade
Bromus/fisiologia
California
Conservação dos Recursos Naturais
Elymus/fisiologia
Monitoramento Ambiental
Estações do Ano
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171031
[Lr] Data última revisão:
171031
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171011
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0181665


  2 / 148 MEDLINE  
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[PMID]:28634255
[Au] Autor:Arnesen S; Coleman CE; Meyer SE
[Ad] Endereço:Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah 84602 USA.
[Ti] Título:Population genetic structure of in the mountains of western North America.
[So] Source:Am J Bot;104(6):879-890, 2017 Jun.
[Is] ISSN:1537-2197
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PREMISE OF THE STUDY: Invasive species are often initially restricted to a narrow range and may then expand through any of multiple mechanisms including phenotypic plasticity, in situ evolution, or selection on traits preadapted for new habitats. Our study used population genetics to explore possible processes by which the highly selfing invasive annual grass has expanded into montane environments. METHODS: We used 69 single nucleotide polymorphic (SNP) markers to genotype ca. 20 individuals from each of 38 montane cheatgrass populations from throughout the Intermountain West and to identify characteristic SNP haplotypes and examine their distribution. KEY RESULTS: Five invariant SNP haplotypes were dominant in montane cheatgrass populations, making up 59% of genotyped individuals, with each haplotype present in 12 to 21 populations. Four of these were absent or present at low frequency in low elevation populations, while the fifth was also sometimes dominant at low elevation. Sixteen haplotypes made up 78% of all genotyped individuals. These haplotypes were distributed across several haplogroups within the clade that also includes most sagebrush steppe lineages. CONCLUSIONS: The wide geographic distribution of several common haplotypes almost completely restricted to montane habitats suggests that dominant lineages in montane populations may possess adaptive syndromes that are preserved through reduced outcrossing rates or negative selection on outcrossed progeny. However, conclusive evidence of such local adaptation requires reciprocal seeding experiments and further characterization of adaptive traits and breeding system characteristics. Other lineages have likely risen to dominance in montane populations through selectively neutral processes.
[Mh] Termos MeSH primário: Bromus/genética
Genética Populacional
Espécies Introduzidas
[Mh] Termos MeSH secundário: Ecossistema
Haplótipos
América do Norte
Polimorfismo de Nucleotídeo Único
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171020
[Lr] Data última revisão:
171020
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170622
[St] Status:MEDLINE
[do] DOI:10.3732/ajb.1700038


  3 / 148 MEDLINE  
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[PMID]:28380537
[Au] Autor:Silva LG; Benedeti PD; Paula EM; Malekjahani F; Amaral PM; Mariz LD; Shenkoru T; Faciola AP
[Ti] Título:Effects of carbohydrate and nitrogen supplementation on fermentation of cheatgrass () in a dual-flow continuous culture system.
[So] Source:J Anim Sci;95(3):1335-1344, 2017 Mar.
[Is] ISSN:1525-3163
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Cheatgrass (CG; ), an introduced winter annual grass, is an aggressive invader of the sagebrush community in the Western United States. Because of its greater flammability, mature CG constitutes a fire hazard leading to repeated wildfires. One fuel-reduction strategy is livestock grazing. The objective of this study was to evaluate the effects of urea, molasses, or a combination of urea and molasses supplementation of a CG-based diet on digestibility, microbial fermentation, bacterial protein synthesis, and nutrient flow using a dual-flow continuous culture system. Eight fermenters were used in a replicate 4 × 4 Latin square design with four 10-d experimental periods. Experimental treatments (DM basis) were 1) forage only (CON), 2) CG plus urea alone (URE; 1.36% urea), 3) CG plus molasses alone (MOL; 15.9% molasses), and 4) CG plus urea and molasses combined (URE+MOL; 1.28% urea plus 19.3% molasses). Each fermenter was fed 72 g/d of DM, and data were analyzed using the GLIMMIX procedure of SAS (SAS Inst. Inc., Cary, NC). The true digestibilities of NDF and ADF were not affected by diets ( > 0.05). Molasses-containing diets had greater true digestibility of OM ( = 0.02). However, true digestibility of CP was increased when molasses was fed alone ( < 0.01). Molasses-containing diets had lower pH ( < 0.01) and greater VFA concentrations ( < 0.01) compared to those of the other diets. The URE+MOL diet resulted in a greater VFA concentration ( < 0.01). Propionate concentration increased ( < 0.01), whereas acetate concentration decreased ( < 0.01) when molasses alone or in combination with urea was added to the diets. Supplying molasses alone resulted in greater ( = 0.03) total branched-chain VFA compared to the other diets. The concentration of NH-N and total N flow increased ( < 0.01) in response to urea supplementation and was greater ( < 0.01) when urea alone was supplemented in the diet. On the other hand, molasses-supplemented diets yielded more non-ammonia N ( < 0.01) and bacterial N ( = 0.04). Supplementation had no effect ( = 0.83) on bacterial efficiency. Results from this study indicate that the addition of urea and molasses in a CG-based diet could improve nutrient supply to animals, notably VFA supply and microbial N supply; however, in the levels tested in this study, it did not improve CG utilization as assessed by NDF digestion.
[Mh] Termos MeSH primário: Bromus/metabolismo
Carboidratos/farmacologia
Fermentação/efeitos dos fármacos
Nitrogênio/farmacologia
[Mh] Termos MeSH secundário: Ração Animal/análise
Animais
Proteínas de Bactérias/metabolismo
Reatores Biológicos/veterinária
Bovinos
Dieta/veterinária
Suplementos Nutricionais/análise
Digestão/efeitos dos fármacos
Masculino
Melaço
Rúmen/metabolismo
Ureia/farmacologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Carbohydrates); 8W8T17847W (Urea); N762921K75 (Nitrogen)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171010
[Lr] Data última revisão:
171010
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170406
[St] Status:MEDLINE
[do] DOI:10.2527/jas.2016.0950


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[PMID]:28140393
[Au] Autor:Mamet SD; Lamb EG; Piper CL; Winsley T; Siciliano SD
[Ad] Endereço:Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
[Ti] Título:Archaea and bacteria mediate the effects of native species root loss on fungi during plant invasion.
[So] Source:ISME J;11(5):1261-1275, 2017 May.
[Is] ISSN:1751-7370
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Although invasive plants can drive ecosystem change, little is known about the directional nature of belowground interactions between invasive plants, native roots, bacteria, archaea and fungi. We used detailed bioinformatics and a recently developed root assay on soils collected in fescue grassland along a gradient of smooth brome (Bromus inermis Leyss) invasion to examine the links between smooth brome shoot litter and root, archaea, bacteria and fungal communities. We examined (1) aboveground versus belowground influences of smooth brome on soil microbial communities, (2) the importance of direct versus microbe-mediated impacts of plants on soil fungal communities, and (3) the web of roots, shoots, archaea, bacteria and fungi interactions across the A and B soil horizons in invaded and non-invaded sites. Archaea and bacteria influenced fungal composition, but not vice versa, as indicated by redundancy analyses. Co-inertia analyses suggested that bacterial-fungal variance was driven primarily by 12 bacterial operational taxonomic units (OTUs). Brome increased bacterial diversity via smooth brome litter in the A horizon and roots in the B horizon, which then reduced fungal diversity. Archaea increased abundance of several bacterial OTUs, and the key bacterial OTUs mediated changes in the fungi's response to invasion. Overall, native root diversity loss and bacterial mediation were more important drivers of fungal composition than were the direct effects of increases in smooth brome. Critically, native plant species displacement and root loss appeared to be the most important driver of fungal composition during invasion. This causal web likely gives rise to the plant-fungi feedbacks, which are an essential factor determining plant diversity in invaded grassland ecosystems.
[Mh] Termos MeSH primário: Archaea/isolamento & purificação
Bactérias/isolamento & purificação
Fungos/isolamento & purificação
Raízes de Plantas/microbiologia
Microbiologia do Solo
[Mh] Termos MeSH secundário: Archaea/classificação
Bactérias/classificação
Biodiversidade
Bromus/microbiologia
Fungos/classificação
Espécies Introduzidas
Interações Microbianas
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170721
[Lr] Data última revisão:
170721
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170201
[St] Status:MEDLINE
[do] DOI:10.1038/ismej.2016.205


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[PMID]:27708059
[Au] Autor:Wright TH; Bower BJ; Chalker JM; Bernardes GJ; Wiewiora R; Ng WL; Raj R; Faulkner S; Vallée MR; Phanumartwiwath A; Coleman OD; Thézénas ML; Khan M; Galan SR; Lercher L; Schombs MW; Gerstberger S; Palm-Espling ME; Baldwin AJ; Kessler BM; Claridge TD; Mohammed S; Davis BG
[Ad] Endereço:Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK.
[Ti] Título:Posttranslational mutagenesis: A chemical strategy for exploring protein side-chain diversity.
[So] Source:Science;354(6312), 2016 11 04.
[Is] ISSN:1095-9203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Posttranslational modification of proteins expands their structural and functional capabilities beyond those directly specified by the genetic code. However, the vast diversity of chemically plausible (including unnatural but functionally relevant) side chains is not readily accessible. We describe C (sp )-C (sp ) bond-forming reactions on proteins under biocompatible conditions, which exploit unusual carbon free-radical chemistry, and use them to form Cß-Cγ bonds with altered side chains. We demonstrate how these transformations enable a wide diversity of natural, unnatural, posttranslationally modified (methylated, glycosylated, phosphorylated, hydroxylated), and labeled (fluorinated, isotopically labeled) side chains to be added to a common, readily accessible dehydroalanine precursor in a range of representative protein types and scaffolds. This approach, outside of the rigid constraints of the ribosome and enzymatic processing, may be modified more generally for access to diverse proteins.
[Mh] Termos MeSH primário: Alanina/análogos & derivados
Carbono/química
Radicais Livres/química
Engenharia de Proteínas/métodos
Processamento de Proteína Pós-Traducional
Proteínas/química
[Mh] Termos MeSH secundário: Alanina/química
Alanina/genética
Bromus/química
Código Genético
Glicosilação
Iodo/química
Mutagênese
Peptídeos/química
Peptídeos/genética
Proteínas/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Free Radicals); 0 (Peptides); 0 (Proteins); 7440-44-0 (Carbon); 9679TC07X4 (Iodine); 98RA387EKY (dehydroalanine); OF5P57N2ZX (Alanine)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170425
[Lr] Data última revisão:
170425
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161007
[St] Status:MEDLINE


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[PMID]:27405299
[Au] Autor:Concilio AL; Nippert JB; Ehrenfeucht S; Cherwin K; Seastedt TR
[Ad] Endereço:Department of Ecology and Evolutionary Biology, Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, 80309, USA. aconcili@stedwards.edu.
[Ti] Título:Imposing antecedent global change conditions rapidly alters plant community composition in a mixed-grass prairie.
[So] Source:Oecologia;182(3):899-911, 2016 Nov.
[Is] ISSN:1432-1939
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Global change drivers are altering climatic and edaphic conditions of ecosystems across the globe, and we expect novel plant communities to become more common as a result. In the Colorado Front Range, compositional changes have occurred in the mixed-grass prairie plant community in conjunction with shifts in winter precipitation and atmospheric nitrogen (N) deposition. To test whether these environmental changes have been responsible for the observed plant community change, we conducted an in situ manipulative experiment in a mixed-grass meadow near Boulder, CO. We simulated historical conditions by reducing N availability (+500 g C m(-2) year(-1)) and winter precipitation (with rainout shelters) for 2 years (2013-2014) and compared vegetation response to these treatments with that of ambient conditions. The site experienced an extreme precipitation event in autumn 2013 which allowed comparison of an exceptionally wet year with an average year. We measured pre-treatment species composition in 2012, and treatment responses in the spring and summer of 2013 and 2014. As predicted, simulating historical low N-winter dry conditions resulted in a plant community dominated by historically abundant species. Cool-season introduced species were significantly reduced in low N-winter dry plots, particularly the annual plants Bromus tectorum and Alyssum parviflorum. These same species responded strongly to the extreme precipitation event with large increases, while native grasses and forbs showed little change in productivity or composition under varying climatic or edaphic conditions. This work provides clear evidence linking on-going global change drivers to altered plant community composition in an otherwise relatively undisturbed grassland ecosystem.
[Mh] Termos MeSH primário: Pradaria
Poaceae
[Mh] Termos MeSH secundário: Animais
Bromus
Ecossistema
Plantas
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1705
[Cu] Atualização por classe:171010
[Lr] Data última revisão:
171010
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160714
[St] Status:MEDLINE
[do] DOI:10.1007/s00442-016-3684-4


  7 / 148 MEDLINE  
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[PMID]:27349093
[Au] Autor:Afkhami ME; Strauss SY
[Ti] Título:Native fungal endophytes suppress an exotic dominant and increase plant diversity over small and large spatial scales.
[So] Source:Ecology;97(5):1159-69, 2016 May.
[Is] ISSN:0012-9658
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Understanding community dynamics and processes, such as the factors that generate and maintain biodiversity, drive succession, and affect invasion susceptibility, is a central goal in ecology and evolution. While most studies of how species interactions affect communities have focused on highly visible macroorganisms, we show that mutualistic microfungal endophytes have community-level effects across their host plant's range and provide the first example of fungal endophytes enhancing plant diversity. A three-year field study in which we experimentally manipulated endophyte abundance in a native Californian grass showed that despite their minute biomass, endophytes dramatically increased plant community diversity (~110% greater increase with endophytes) by suppressing a dominant invasive grass, Bromus diandrus. This effect was also detectable, but smaller, across five additional common gardens spanning ecologically diverse habitats, different climates, and > 400 km of the host grass' range as well as at microspatial scales within gardens. Our study illustrates that mutualistic microbes, while often hidden players, can have unexpectedly large ecological impacts across a wide range of habitats and scales and may be important for promoting diverse communities and ecosystems.
[Mh] Termos MeSH primário: Biodiversidade
Bromus/fisiologia
Endófitos/fisiologia
Fungos/classificação
Espécies Introduzidas
[Mh] Termos MeSH secundário: Bromus/classificação
Bromus/microbiologia
California
Demografia
Fungos/fisiologia
Simbiose
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Em] Mês de entrada:1607
[Cu] Atualização por classe:160628
[Lr] Data última revisão:
160628
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160629
[St] Status:MEDLINE


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[PMID]:27120201
[Au] Autor:Palik DJ; Snow AA; Stottlemyer AL; Miriti MN; Heaton EA
[Ad] Endereço:Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, Ohio, United States of America.
[Ti] Título:Relative Performance of Non-Local Cultivars and Local, Wild Populations of Switchgrass (Panicum virgatum) in Competition Experiments.
[So] Source:PLoS One;11(4):e0154444, 2016.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The possibility of increased invasiveness in cultivated varieties of native perennial species is a question of interest in biofuel risk assessment. Competitive success is a key factor in the fitness and invasive potential of perennial plants, and thus the large-scale release of high-yielding biomass cultivars warrants empirical comparisons with local conspecifics in the presence of competitors. We evaluated the performance of non-local cultivars and local wild biotypes of the tallgrass species Panicum virgatum L. (switchgrass) in competition experiments during two growing seasons in Ohio and Iowa. At each location, we measured growth and reproductive traits (plant height, tiller number, flowering time, aboveground biomass, and seed production) of four non-locally sourced cultivars and two locally collected wild biotypes. Plants were grown in common garden experiments under three types of competition, referred to as none, moderate (with Schizachyrium scoparium), and high (with Bromus inermis). In both states, the two "lowland" cultivars grew taller, flowered later, and produced between 2x and 7.5x more biomass and between 3x and 34x more seeds per plant than local wild biotypes, while the other two cultivars were comparable to wild biotypes in these traits. Competition did not affect relative differences among biotypes, with the exception of shoot number, which was more similar among biotypes under high competition. Insights into functional differences between cultivars and wild biotypes are crucial for developing biomass crops while mitigating the potential for invasiveness. Here, two of the four cultivars generally performed better than wild biotypes, indicating that these biotypes may pose more of a risk in terms of their ability to establish vigorous feral populations in new regions outside of their area of origin. Our results support an ongoing assessment of switchgrass cultivars developed for large-scale planting for biofuels.
[Mh] Termos MeSH primário: Espécies Introduzidas
Panicum/crescimento & desenvolvimento
Dispersão Vegetal/fisiologia
Sementes/crescimento & desenvolvimento
[Mh] Termos MeSH secundário: Andropogon/crescimento & desenvolvimento
Biocombustíveis/provisão & distribuição
Bromus/crescimento & desenvolvimento
Conservação dos Recursos Naturais
Iowa
Ohio
Melhoramento Vegetal
Dispersão Vegetal/ética
Brotos de Planta/crescimento & desenvolvimento
Estações do Ano
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Biofuels)
[Em] Mês de entrada:1703
[Cu] Atualização por classe:170321
[Lr] Data última revisão:
170321
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160428
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0154444


  9 / 148 MEDLINE  
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[PMID]:27090757
[Au] Autor:Blumenthal DM; Kray JA; Ortmans W; Ziska LH; Pendall E
[Ad] Endereço:Rangeland Resources Research Unit, USDA Agricultural Research Service, Fort Collins, CO, USA.
[Ti] Título:Cheatgrass is favored by warming but not CO2 enrichment in a semi-arid grassland.
[So] Source:Glob Chang Biol;22(9):3026-38, 2016 Sep.
[Is] ISSN:1365-2486
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Elevated CO2 and warming may alter terrestrial ecosystems by promoting invasive plants with strong community and ecosystem impacts. Invasive plant responses to elevated CO2 and warming are difficult to predict, however, because of the many mechanisms involved, including modification of phenology, physiology, and cycling of nitrogen and water. Understanding the relative and interactive importance of these processes requires multifactor experiments under realistic field conditions. Here, we test how free-air CO2 enrichment (to 600 ppmv) and infrared warming (+1.5 °C day/3 °C night) influence a functionally and phenologically distinct invasive plant in semi-arid mixed-grass prairie. Bromus tectorum (cheatgrass), a fast-growing Eurasian winter annual grass, increases fire frequency and reduces biological diversity across millions of hectares in western North America. Across 2 years, we found that warming more than tripled B. tectorum biomass and seed production, due to a combination of increased recruitment and increased growth. These results were observed with and without competition from native species, under wet and dry conditions (corresponding with tenfold differences in B. tectorum biomass), and despite the fact that warming reduced soil water. In contrast, elevated CO2 had little effect on B. tectorum invasion or soil water, while reducing soil and plant nitrogen (N). We conclude that (1) warming may expand B. tectorum's phenological niche, allowing it to more successfully colonize the extensive, invasion-resistant northern mixed-grass prairie, and (2) in ecosystems where elevated CO2 decreases N availability, CO2 may have limited effects on B. tectorum and other nitrophilic invasive species.
[Mh] Termos MeSH primário: Bromus
Ecossistema
Pradaria
[Mh] Termos MeSH secundário: América do Norte
Poaceae
Solo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Soil)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160420
[St] Status:MEDLINE
[do] DOI:10.1111/gcb.13278


  10 / 148 MEDLINE  
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[PMID]:26920900
[Au] Autor:Bansal S; Sheley RL
[Ad] Endereço:USDA-Agricultural Research Service, Eastern Oregon Agricultural Research Center, 67826-A Hwy 205, Burns, OR, 97720, USA. sheelbansal9@gmail.com.
[Ti] Título:Annual grass invasion in sagebrush steppe: the relative importance of climate, soil properties and biotic interactions.
[So] Source:Oecologia;181(2):543-57, 2016 Jun.
[Is] ISSN:1432-1939
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:The invasion by winter-annual grasses (AGs) such as Bromus tectorum into sagebrush steppe throughout the western USA is a classic example of a biological invasion with multiple, interacting climate, soil and biotic factors driving the invasion, although few studies have examined all components together. Across a 6000-km(2) area of the northern Great Basin, we conducted a field assessment of 100 climate, soil, and biotic (functional group abundances, diversity) factors at each of 90 sites that spanned an invasion gradient ranging from 0 to 100 % AG cover. We first determined which biotic and abiotic factors had the strongest correlative relationships with AGs and each resident functional group. We then used regression and structural equation modeling to explore how multiple ecological factors interact to influence AG abundance. Among biotic interactions, we observed negative relationships between AGs and biodiversity, perennial grass cover, resident species richness, biological soil crust cover and shrub density, whereas perennial and annual forb cover, tree cover and soil microbial biomass had no direct linkage to AG. Among abiotic factors, AG cover was strongly related to climate (increasing cover with increasing temperature and aridity), but had weak relationships with soil factors. Our structural equation model showed negative effects of perennial grasses and biodiversity on AG cover while integrating the negative effects of warmer climate and positive influence of belowground processes on resident functional groups. Our findings illustrate the relative importance of biotic interactions and climate on invasive abundance, while soil properties appear to have stronger relationships with resident biota than with invasives.
[Mh] Termos MeSH primário: Poaceae
Solo
[Mh] Termos MeSH secundário: Artemisia
Bromus
Clima
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Soil)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160228
[St] Status:MEDLINE
[do] DOI:10.1007/s00442-016-3583-8



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