Description:
Conservation agriculture (CA) may become a preferred cultivation system in the future as a tool to mitigate climate change through improved carbon storage. Less is known, however, about the effect of CA on biodiversity. Yet biodiversity is also under pressure throughout the world, and the biodiversity crisis and the climate crisis should be addressed together.In the current study, the density and diversity of epiedaphic (surface-dwelling) springtails, beetles and spiders were investigated over three years on two organic and two conventional farms. The experimental set-up was a randomized block design of four blocks each with four cultivation systems: 1) conventional tillage (CT) with moldbord ploughing, 2) non-inversion tillage (NIT), 3) conservation agriculture (CA) with no-tilling except hoeing for weed control in the organic systems, 4) CA with extended utilization of cover crops (CA+) and no hoeing in the organic systems.The working hypothesis was that CA, by adding plant matter to the base, enhances a food web consisting of dead crop residues, degrading bacteria and fungi, springtails, epiedaphic spiders and beetles and, at the top, birds. This was named the “feed the food web hypothesis”. ‘Strong positive effects of the CA and CA+ systems were demonstrated in terms of density and diversity of epiedaphic springtails compared to CT and NIT in all ten datasets, which supports the “feed the food web hypothesis”. Furthermore, significant effects were found on densities of several epiedaphic springtail species or genera. A positive effect of NIT was also detected compared to CT.The results were more inconsistent for spiders and epiedaphic beetles; positive effects of CA on densities of spiders and beetles were demonstrated, respectively, in only three and two datasets out of ten while significant effects on ground beetle species richness were found in only two datasets. The inconsistent effect of CA on spiders and beetles may be due to high mobility of these organisms which can move easily from one plot to another.The strong support for the “feed the food web hypothesis“ at the level of springtails, which constitutes the foundation for higher trophic level effects, suggests that CA can be used as a tool in biodiversity crisis mitigation