TY  - JOUR
A1  - Socher, Stephanie A.
A1  - Prati, Daniel
A1  - Boch, Steffen
A1  - Müller, Jörg
A1  - Klaus, Valentin H.
A1  - Hölzel, Norbert
A1  - Fischer, Markus
T1  - Direct and productivity-mediated indirect effects of fertilization, mowing and grazing on grassland species richness
JF  - The journal of ecology
N2  - Recent declines in biodiversity have given new urgency to questions about the relationship between land-use change, biodiversity and ecosystem processes. Despite the existence of a large body of research on the effects of land use on species richness, it is unclear whether the effects of land use on species richness are principally direct or indirect, mediated by concomitant changes in ecosystem processes. Therefore, we compared the direct effects of land use (fertilization, mowing and grazing) on species richness with indirect ones (mediated via grassland productivity) for grasslands in central Europe. We measured the richness and above-ground biomass in 150 grassland plots in 3 regions of Germany (the so-called Biodiversity Exploratories). We used univariate and structural equation models to examine direct and indirect land-use effects. The direct effects of mowing (-0.37, effect size) and grazing (0.04) intensity on species richness were stronger compared with the indirect effects of mowing (-0.04) and grazing (-0.01). However, the strong negative effect of fertilization (-0.23) on species richness was mainly indirect, mediated by increased productivity compared with the weak direct negative effect (-0.07). Differences between regions in land-use effects showed five times weaker negative effects of mowing (-0.13) in the region with organic soils (Schorfheide-Chorin), strong overall negative effects of grazing (-0.29) for the region with organic soils opposed to a similar strong positive effect (0.30) in the Hainich-Dun region, whereas the Schwabische Alb region displayed a five times weaker positive effect (0.06) only. Further, fertilization effects on species richness were positive (0.03) for the region with organic soils compared to up to 25 times stronger negative effects in the other two regions. Synthesis. Our results clearly show the importance of studying both direct and indirect effects of land-use intensity. They demonstrate the indirect nature, via productivity, of the negative effect of fertilization intensity on plant species richness in the real-world context of management-induced gradients of intensity of fertilization, mowing and grazing. Finally, they highlight that careful consideration of regional environments is necessary before attempting to generalize land-use effects on species diversity.
KW  - biodiversity
KW  - determinants of plant community diversity and structure
KW  - ecosystem functioning
KW  - functional plant group
KW  - land use
KW  - productivity
KW  - species richness
KW  - structural equation modelling
Y1  - 2012
U6  - https://doi.org/10.1111/j.1365-2745.2012.02020.x
SN  - 0022-0477
VL  - 100
IS  - 6
SP  - 1391
EP  - 1399
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Soliveres, Santiago
A1  - Maestre, Fernando T.
A1  - Ulrich, Werner
A1  - Manning, Peter
A1  - Boch, Steffen
A1  - Bowker, Matthew A.
A1  - Prati, Daniel
A1  - Delgado-Baquerizo, Manuel
A1  - Quero, Jose L.
A1  - Schöning, Ingo
A1  - Gallardo, Antonio
A1  - Weisser, Wolfgang W.
A1  - Müller, Jörg
A1  - Socher, Stephanie A.
A1  - Garcia-Gomez, Miguel
A1  - Ochoa, Victoria
A1  - Schulze, Ernst-Detlef
A1  - Fischer, Markus
A1  - Allan, Eric
T1  - Intransitive competition is widespread in plant communities and maintains their species richness
JF  - Ecology letters
N2  - Intransitive competition networks, those in which there is no single best competitor, may ensure species coexistence. However, their frequency and importance in maintaining diversity in real-world ecosystems remain unclear. We used two large data sets from drylands and agricultural grasslands to assess: (1) the generality of intransitive competition, (2) intransitivity-richness relationships and (3) effects of two major drivers of biodiversity loss (aridity and land-use intensification) on intransitivity and species richness. Intransitive competition occurred in >65% of sites and was associated with higher species richness. Intransitivity increased with aridity, partly buffering its negative effects on diversity, but was decreased by intensive land use, enhancing its negative effects on diversity. These contrasting responses likely arise because intransitivity is promoted by temporal heterogeneity, which is enhanced by aridity but may decline with land-use intensity. We show that intransitivity is widespread in nature and increases diversity, but it can be lost with environmental homogenisation.
KW  - Aridity
KW  - biodiversity
KW  - coexistence
KW  - drylands
KW  - land use
KW  - mesic grasslands
KW  - rock-paper-scissors game
Y1  - 2015
U6  - https://doi.org/10.1111/ele.12456
SN  - 1461-023X
SN  - 1461-0248
VL  - 18
IS  - 8
SP  - 790
EP  - 798
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -