【植物多样性、大气CO2和N沉降对土壤食物网的影响】Nico Eisenhauer Tomasz Dobies Simone Cesarz Sarah E. Hobbie Ross J. Meyer Kally Worm and Peter B. Reich. Plant diversity effects on soil food webs are stronger than those of elevated CO₂and N deposition in a long-term grassland experiment. PNAS April 23 2013 vol. 110 no. 17 6889-6894

Abstract

Recent metaanalyses suggest biodiversity loss affects the functioning of ecosystems to a similar extent as other global environmental change agents. However the abundance and functioning of soil organisms have been hypothesized to be much less responsive to such changes particularly in plant diversity than aboveground variables although tests of this hypothesis are extremely rare. We examined the responses of soil food webs (soil microorganisms nematodes microarthropods) to 13-y manipulation of multiple environmental factors that are changing at global scales—specifically plant species richness atmospheric CO₂ and N deposition—in a grassland experiment in Minnesota. Plant diversity was a strong driver of the structure and functioning of soil food webs through several bottom-up (resource control) effects whereas CO₂ and N only had modest effects. We found few interactions between plant diversity and CO₂ and N likely because of weak interactive effects of those factors on resource availability (e.g. root biomass). Plant diversity effects likely were large because high plant diversity promoted the accumulation of soil organic matter in the site’s sandy organic matter–poor soils. Plant diversity effects were not explained by the presence of certain plant functional groups. Our results underline the prime importance of plant diversity loss cascading to soil food webs (density and diversity of soil organisms) and functions. Because the present results suggest prevailing plant diversity effects and few interactions with other global change drivers protecting plant diversity may be of high priority to maintain the biodiversity and functioning of soils in a changing world.