Within-population genetic structure in beech (Fagus sylvatica L.) stands characterized by different disturbance histories: does forest management simplify population substructure?
Piotti, A. ; Leonardi, S. ; Heuertz, M. ; Buiteveld, J. ; Geburek, T. ; Gerber, S. ; Kramer, K. ; Vettori, C. ; Vendramin, G.G. - \ 2013
PLoS ONE 8 (2013)9. - ISSN 1932-6203 - 9 p.
european beech - populus-trichocarpa - natural-populations - plant-populations - pollen dispersal - estimating seed - f-statistics - null alleles - douglas-fir - white-pine
The fine-scale assessment of both spatially and non-spatially distributed genetic variation is crucial to preserve forest genetic resources through appropriate forest management. Cryptic within-population genetic structure may be more common than previously thought in forest tree populations, which has strong implications for the potential of forests to adapt to environmental change. The present study was aimed at comparing within-population genetic structure in European beech (Fagus sylvatica L.) plots experiencing different disturbance levels. Five plot pairs made up by disturbed and undisturbed plots having the same biogeographic history were sampled throughout Europe. Overall, 1298 individuals were analyzed using four highly polymorphic nuclear microsatellite markers (SSRs). Bayesian clustering within plots identified 3 to 11 genetic clusters (within-plot hST ranged from 0.025 to 0.124). The proportion of within-population genetic variation due to genetic substructuring (FCluPlot = 0.067) was higher than the differentiation among the 10 plots (FPlotTot = 0.045). Focusing on the comparison between managed and unmanaged plots, disturbance mostly explains differences in the complexity of within-population genetic structure, determining a reduction of the number of genetic clusters present in a standardized area. Our results show that: i) genetic substructuring needs to be investigated when studying the within-population genetic structure in forest tree populations, and ii) indices describing subtle characteristics of the within-population genetic structure are good candidates for providing early signals of the consequences of forest management, and of disturbance events in general.
Limits of windthrow-driven hillslope sediment flux due to varying storm frequency and intensity
Constatine, J.A. ; Schelhaas, M.J. ; Gabet, E. ; Mudd, S.M. - \ 2012
Geomorphology 175-176 (2012). - ISSN 0169-555X - p. 66 - 73.
process-based model - forest dynamics - douglas-fir - catastrophic windthrow - north-carolina - root throw - wind-throw - disturbance - transport - trees
The uprooting and toppling of trees during storms transports soil, exhumes bedrock, and thus influences the evolution of hillslopes. Given predicted increased storminess due to future climate change, we adapt a forest-gap model (ForGEM) to explore windthrow-driven sediment transport in a Douglas fir forest under increasingly severe wind regimes in order to better assess potential future impacts on soil erosion. Larger trees are more sensitive to wind loading and are therefore preferentially toppled as storm frequency and intensity increase. Because larger trees have larger root-plate volumes and can move large volumes of sediment, increased wind velocities lead to an increase in sediment flux. With increasingly stormier conditions, however, the proportion of large trees dwindles. The net effect of these two countervailing trends is that sediment transport increases as average annual rates of windthrow approach eight trees per hectare, but begins to decline thereafter. Our results highlight the complex relationship between climate and sediment transport, particularly when it is mediated by the biota.
Modelling the impact of nitrogen deposition, climate change and nutrient limitations on tree carbon sequestration in Europe for the period 1900–2050
Vries, W. de; Posch, M. - \ 2011
Environmental Pollution 159 (2011)10. - ISSN 0269-7491 - p. 2289 - 2299.
forest ecosystems - elevated co2 - terrestrial ecosystems - primary productivity - tropospheric ozone - temperate forests - projected changes - acid deposition - boreal forests - douglas-fir
We modelled the combined effects of past and expected future changes in climate and nitrogen deposition on tree carbon sequestration by European forests for the period 1900–2050. Two scenarios for deposition (current legislation and maximum technically feasible reductions) and two climate scenarios (no change and SRES A1 scenario) were used. Furthermore, the possible limitation of forest growth by calcium, magnesium, potassium and phosphorus is investigated. The area and age structure of the forests was assumed to stay constant to observations during the period 1970–1990. Under these assumptions, the simulations show that the change in forest growth and carbon sequestration in the past is dominated by changes in nitrogen deposition, while climate change is the major driver for future carbon sequestration. However, its impact is reduced by nitrogen availability. Furthermore, limitations in base cations, especially magnesium, and in phosphorus may significantly affect predicted growth in the future. A modelling exercise indicates that nitrogen deposition mainly enhanced tree carbon sequestration in Europe in the past, while climate change will do so in the future
Ectomycorrhizal fungal diversity: seperating the wheat from the chaff
Rinaldi, A.C. ; Comandini, O. ; Kuyper, T.W. - \ 2008
Fungal Diversity 33 (2008). - ISSN 1560-2745 - p. 1 - 45.
truffle-like fungi - n-15 isotopic fractionation - ribosomal dna-sequences - pure culture synthesis - mixed-conifer forest - picea-abies - norway spruce - molecular phylogeny - douglas-fir - new-zealand
Thousands of ectomycorrhizal (ECM) fungal species exist, but estimates of global species richness of ECM fungi differ widely. Many genera have been proposed as being ECM, but ill a number of studies evidence for the hypothesized ECM habit is lacking. Progress in estimating ECM species richness is therefore slow. Ill this paper we have retrieved studies providing evidence for the ECM habit of fungal species and For the identification of the mycobiont(s) ill specific ECM associations, using published and web-based mycorrhiza literature. The identification methods considered are morpho-anatomical, characterization or naturally occurring ECMs, pure Culture synthesis, molecular identification, and isotopic evidence. In addition, phylogenetic information is also considered as a relevant criterion to assess ECM habit. OF 343 fungal genera for which all ECM status has been alleged, about two thirds have Supportive published evidence or ECM Status can be at least hypothesized. For the remaining taxa, Currently no indication exists as for their I-CM nutritional habit, besides field observations or associations with putative hosts. Our survey clearly indicates that current knowledge of ECM fungal diversity, as Supported by experimental evidence, is only partly complete, and that inclusion of many Funga genera in this trophic and ecological category is not verified at this stage. Care must thus be used when compiling lists of ECM and saprotrophic full studies oil the basis of published information only. On the basis of our literature search we conservatively estimate ECM species richness around 7750 species. However, oil the basis of estimates of knowns and unknowns in macromycete diversity, a final estimate or ECM species richness Would likely be between 20000 and 25000.
Genetic diversity and differentiation in European beech (Fagus sylvatica L.) stands varying in management history
Buiteveld, J. ; Vendramin, G.G. ; Leonardi, S. ; Kramer, K. ; Geburek, T. - \ 2007
Forest Ecology and Management 247 (2007)1-3. - ISSN 0378-1127 - p. 98 - 106.
microsatellite markers - natural-populations - spatial differentiation - f-statistics - douglas-fir - regeneration - crenata - consequences - silviculture - variability
The impact of forest management on genetic diversity and mating was examined in European beech (Fagus sylvatica L.). Ten beech stands located in Europe were studied in pair-wise plots, differing in management intensity. The stands were genotyped with four highly polymorphic microsatellite loci. Comparison for genetic diversity measures between the stands with limited management and the high management-intensity stands (mostly shelter wood system) revealed no significant differences for allelic richness (A), effective number of alleles (Ae), number of rare alleles (Arare), neither for observed (Ho) nor expected heterozygosity (He). In all stands a significant excess of homozygotes was found, which is in agreement with previous isozyme publications. However, the increase in the inbreeding coefficient (Fis) in the stands with limited management was significantly higher than in the highly managed stands. Expectedly a low, but significant, differentiation among all stands was found (Fst = 0.058) which still reveals a clear geographic structure. The results indicate that the shelter wood system has no or minimum impact on the genetic diversity in European beech.
Direct and indirect chemical defence of pine against folivorous insects
Mumm, R. ; Hilker, M. - \ 2006
Trends in Plant Science 11 (2006)7. - ISSN 1360-1385 - p. 351 - 358.
dependent pheromone responses - spruce budworm defoliation - sawfly diprion-pini - scots pine - bark beetles - lodgepole pine - egg deposition - douglas-fir - natural defoliation - volatile emissions
The chemical defence of pine against herbivorous insects has been intensively studied with respect to its effects on the performance and behaviour of the herbivores as well as on the natural enemies of pine herbivores. The huge variety of terpenoid pine components play a major role in mediating numerous specific food web interactions. The constitutive terpenoid pattern can be adjusted to herbivore attack by changes induced by insect feeding or oviposition activity. Recent studies on folivorous pine sawflies have highlighted the role of induced pine responses in herbivore attack and have demonstrated the importance of analysing the variability of pine defence and its finely tuned specificity with respect to the herbivore attacker in a multitrophic context.
Ectomycorrhizal symbiosis affects functional diversity of rhizosphere fluorescent pseudomonads
Frey-Klett, P. ; Chavatte, M. ; Clausse, M.L. ; Courrier, S. ; Roux, C. Le; Raaijmakers, J.M. ; Giovanna Martinotti, M. ; Pierrat, J.C. ; Garbaye, J. - \ 2005
New Phytologist 165 (2005)1. - ISSN 0028-646X - p. 317 - 328.
phosphate-solubilizing bacteria - arbuscular mycorrhizal fungus - douglas-fir - laccaria-bicolor - helper bacteria - sustainable agriculture - siderophore production - biological-control - microbial activity - root colonization
Here we characterized the effect of the ectomycorrhizal symbiosis on the genotypic and functional diversity of soil Pseudomonas fluorescens populations and analysed its possible consequences in terms of plant nutrition, development and health. ¿ Sixty strains of P. fluorescens were isolated from the bulk soil of a forest nursery, the ectomycorrhizosphere and the ectomycorrhizas of the Douglas fir (Pseudostuga menziesii) seedlings-Laccaria bicolor S238N. They were characterized in vitro with the following criteria: ARDRA, phosphate solubilization, siderophore, HCN and AIA production, genes of N2-fixation and antibiotic synthesis, in vitro confrontation with a range of phytopathogenic and ectomycorrhizal fungi, effect on the Douglas fir¿L. bicolor symbiosis. ¿ For most of these criteria, we demonstrated that the ectomycorrhizosphere significantly structures the P. fluorescens populations and selects strains potentially beneficial to the symbiosis and to the plant. ¿ This prompts us to propose the ectomycorrhizal symbiosis as a true microbial complex where multitrophic interactions take place. Moreover it underlines the fact that this symbiosis has an indirect positive effect on plant growth, via its selective pressure on bacterial communities, in addition to its known direct positive effect.