Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1093/jpe/rtw013
Title (Primary) Positive diversity effects on productivity in mixtures of arable weed species as related to density–size relationships
Author Roscher, C.; Schumacher, J.
Source Titel Journal of Plant Ecology
Year 2016
Department iDiv; PHYDIV
Volume 9
Issue 6
Page From 792
Page To 804
Language englisch
Keywords allometry; biodiversity; complementarity effects; density; selection effects
UFZ wide themes RU1

Aims Diversity–productivity relationships among herbaceous species have mostly been studied in grasslands, while less is known about diversity effects among weedy species with a short life cycle.

Methods We studied diversity–productivity relationships, shoot density, size and allometry in experimental communities of different species richness (one, three, six, and nine species), functional group number (one to three functional groups: grasses, small herbs and tall herbs) and functional group evenness (even and uneven number of species per functional group) based on a pool of nine arable weed species with a short life cycle in a 2-year experiment.

Important Findings Higher species richness increased above- and belowground biomass production in both years of the experiment. Additive partitioning showed that positive selection effects increased with increasing species richness and functional group number, while positive complementarity effects were greater when tall herbs were present. Relative yield totals were larger than 1 across all species richness levels but did not increase with species richness, which is consistent with constant positive complementarity effects. Community biomass production and diversity effects increased in the second year of the experiment, when communities achieved greater shoot densities and average shoot sizes. At the community level, varying productivity was mainly attributable to variation in mean shoot sizes. Tall herbs reached greater observed/expected relative yields (=overyielding) due to increased shoot sizes, underyielding of small herbs was mainly attributable to decreased shoot sizes, while grasses partly compensated for reduced shoot sizes by increasing densities. Shifts in community-level density–size relationships and changes in shoot allometry in favour of greater height growth indicated that a greater biomass at a given density was due to increased dimensions of occupied canopy space. We conclude that diversity effects are also possible among short-lived arable weed species, but selection effects through sizes differences among species are key for positive species richness–productivity relationships.

Persistent UFZ Identifier
Roscher, C., Schumacher, J. (2016):
Positive diversity effects on productivity in mixtures of arable weed species as related to density–size relationships
J. Plant Ecol. 9 (6), 792 - 804 10.1093/jpe/rtw013