21 research outputs found
Elevated CO2 increased phosphorous loss from decomposing litter and soil organic matter at two FACE experiments with trees
Conservation of Mediterranean oak woodlands: understorey dynamics under different shrub management
The effect of experimental disturbances
on the dynamics of a shrub community was studied
on a ‘Montado’ ecosystem, in southern Portugal. The
evolution of the community physiognomy, composition
and diversity were monitored after shrub clearing
followed by biomass removal, deposition on soil
surface and incorporation with the soil, over a 9-year
period. Maximum shrub density was recorded in the
first year after the disturbances, excepting in mulched
plots which showed the greatest number of individuals
1 year later. The increment of shrub leaf biomass
was very fast in the first 3 years, whereas wood
production was slower but occurred along the whole
study period. At the end of the study, leaf and wood
biomass was still significantly lower than in the predisturbance
situation. The variation pattern of leaf
area index was similar to that of leaf biomass. The
evolution of total plant cover and diversity was
similar across treatments. The highest species richness
and diversity were recorded 2 years after
cutting, decreasing afterwards with the increasing
dominance of shrubs. Thus it seems likely that,
although a 9 year period is too short for these
communities to reach steady equilibrium, they are
very resistant and resilient to disturbances, as regeneration
was fast and vegetation dynamics was not
influenced by differences among treatments. We can
conclude that shrub clearing promotes biodiversity
and the time of permanence of shrub patches depends
on the particular goal we want to achieve
Conservation of Mediterranean oak woodlands: understorey dynamics under different shrub management
The effect of experimental disturbances
on the dynamics of a shrub community was studied
on a ‘Montado’ ecosystem, in southern Portugal. The
evolution of the community physiognomy, composition
and diversity were monitored after shrub clearing
followed by biomass removal, deposition on soil
surface and incorporation with the soil, over a 9-year
period. Maximum shrub density was recorded in the
first year after the disturbances, excepting in mulched
plots which showed the greatest number of individuals
1 year later. The increment of shrub leaf biomass
was very fast in the first 3 years, whereas wood
production was slower but occurred along the whole
study period. At the end of the study, leaf and wood
biomass was still significantly lower than in the predisturbance
situation. The variation pattern of leaf
area index was similar to that of leaf biomass. The
evolution of total plant cover and diversity was
similar across treatments. The highest species richness
and diversity were recorded 2 years after
cutting, decreasing afterwards with the increasing
dominance of shrubs. Thus it seems likely that,
although a 9 year period is too short for these
communities to reach steady equilibrium, they are
very resistant and resilient to disturbances, as regeneration
was fast and vegetation dynamics was not
influenced by differences among treatments. We can
conclude that shrub clearing promotes biodiversity
and the time of permanence of shrub patches depends
on the particular goal we want to achieve
Conservation of Mediterranean oak woodlands: understorey dynamics under different shrub management
Two quantitative trait loci, Dw1 and Dw2, are primarily responsible for rootstock-induced dwarfing in apple
The apple dwarfing rootstock ‘Malling9’ (‘M9’) has been used worldwide both to reduce scion vigour and as a genetic source for breeding new rootstocks. Progeny of ‘M9’ segregate for rootstock-induced dwarfing of the scion, indicating that this trait is controlled by one or more genetic factors. A quantitative trait locus (QTL) analysis of a rootstock population derived from the cross between ‘M9’ × ‘Robusta5’ (non-dwarfing) and grafted with ‘Braeburn’ scions identified a major QTL (Dw1) on linkage group (LG) 5, which exhibits a significant influence on dwarfing of the scion. A smaller-effect QTL affecting dwarfing (Dw2) was identified on LG11, and four minor-effect QTLs were found on LG6, LG9, LG10 and LG12. Phenotypic analysis indicates that the combination of Dw1 and Dw2 has the strongest influence on rootstock-induced dwarfing, and that Dw1 has a stronger effect than Dw2. Genetic markers linked to Dw1 and Dw2 were screened over 41 rootstock accessions that confer a range of effects on scion growth. The majority of the dwarfing and semi-dwarfing rootstock accessions screened carried marker alleles linked to Dw1 and Dw2. This suggests that most apple dwarfing rootstocks have been derived from the same genetic source