Consistent functional clusters explain the effects of biodiversity on ecosystem productivity in a long-term experiment.

Biomass production in ecosystems is a complex process regulated by several facets of biodiversity and species identity, but also species interactions such as competition or complementarity between species. For studying these different facets separately, ecosystem biomass is generally partitioned in two biodiversity effects. The composition effect is a simple, linear effect, and the interaction effect is a more subtle, nonlinear effect.

Concurrent starch accumulation in stump and high fruit production in coffee (Coffea arabica).

In coffee, fruit production on a given shoot drops after some years of high yield, triggering pruning to induce resprouting. The timing of pruning is a crucial farmer's decision affecting yield and labour. One reason for fruit production drop could be the exhaustion of resources, particularly the non-structural carbohydrates (NSC).

Correction: A combinatorial analysis using observational data identifies species that govern ecosystem functioning.

[This corrects the article DOI: 10.1371/journal.pone.

A combinatorial analysis using observational data identifies species that govern ecosystem functioning.

Understanding the relationship between biodiversity and ecosystem functioning has so far resulted from two main approaches: the analysis of species' functional traits, and the analysis of species interaction networks. Here we propose a third approach, based on the association between combinations of species or of functional groups, which we term assembly motifs, and observed ecosystem functioning. Each assembly motif describes a biotic environment in which species interactions have particular effects on a given ecosystem function.

Is the simple auger coring method reliable for below-ground standing biomass estimation in Eucalyptus forest plantations?

Background And Aims: Despite their importance for plant production, estimations of below-ground biomass and its distribution in the soil are still difficult and time consuming, and no single reliable methodology is available for different root types. To identify the best method for root biomass estimations, four different methods, with labour requirements, were tested at the same location.

Methods: The four methods, applied in a 6-year-old Eucalyptus plantation in Congo, were based on different soil sampling volumes: auger (8 cm in diameter), monolith (25 × 25 cm quadrate), half Voronoi trench (1·5 m(3)) and a full Voronoi trench (3 m(3)), chosen as the reference method.

Nutrient dynamics throughout the rotation of Eucalyptus clonal stands in Congo.

The dynamics of the main nutrient fluxes of the biological cycle were quantified in a clonal Eucalyptus plantation throughout the whole planted crop rotation: current annual requirements of nutrients, uptake from the soil, internal translocations within trees, return to soil (litterfall and crown leaching) and decomposition in the forest floor. As reported for other species, two growth periods were identified in these short-rotation plantations: (1) a juvenile phase up to canopy closure, during which the uptake of nutrients from the soil reserves supplied most of the current requirements; and (2) a second phase up to harvest, characterized by intense nutrient recycling processes. Internal translocation within trees supplied about 30 % of the annual requirements of N and P from 2 years of age onwards, and about 50 % of the K requirement.

A generic model to describe the dynamics of nutrient concentrations within stemwood across an age series of a eucalyptus hybrid.

Nutrient concentrations (N, P, K) were determined within stemwood in an age series of eucalyptus stands. Four trees per stand were selected according to their size to represent the whole range of basal areas in 1-, 2-, 3-, 4-, 5-, 6- and 7-year-old stands. Cross-sections were sampled every 4 m from the ground to the top of the tree, and chemical analyses were performed for each annual ring in the cross-sections.