Knops Johannes M H, Wedin D, Tilman David
School of Biological Sciences, University of Nebraska, Lincoln, 348 Manter Hall, 68588, Lincoln, NE, USA.
School of Natural Resource Sciences, University of Nebraska, 68583, Lincoln, NE, USA.
Oecologia. 2001 Feb;126(3):429-433. doi: 10.1007/s004420000537. Epub 2001 Feb 1.
We examined the impact of biodiversity on litter decomposition in an experiment that manipulated plant species richness. Using biomass originating from the experimental species richness gradient and from a species used as a common substrate, we measured rates of decomposition in litterbags in two locations: in situ in the experiment plots and in an adjacent common garden. This allowed us to separate the effects of litter quality and decomposition location on decomposition. We found that plant species richness had a significant, but minor negative effect on the quality (nitrogen concentration) of the biomass. Neither litter type nor location had a consistent effect on the rate of carbon and nitrogen loss over a 1-year period. Thus, the increased productivity and corresponding lower soil available nitrogen levels observed in high diversity plots do not lead to faster litter decomposition or faster nitrogen turnover. This supports the hypothesis that increased productivity corresponding with higher species richness results in increased litter production, higher standing litter pools and a negative feedback on productivity, because of an increased standing nitrogen pool in the litter.
我们在一项操纵植物物种丰富度的实验中，研究了生物多样性对凋落物分解的影响。利用源自实验物种丰富度梯度以及用作常见底物的一个物种的生物量，我们在两个地点测量了垃圾袋中的分解速率：在实验地块原地以及在相邻的普通园圃中。这使我们能够区分凋落物质量和分解地点对分解的影响。我们发现植物物种丰富度对生物量的质量（氮浓度）有显著但较小的负面影响。在一年的时间里，凋落物类型和地点对碳和氮的损失速率均没有一致的影响。因此，在高多样性地块中观察到的生产力提高以及相应较低的土壤有效氮水平，并不会导致更快的凋落物分解或更快的氮周转。这支持了以下假设：与更高物种丰富度相对应的生产力提高会导致凋落物产量增加、现存凋落物库增大，并由于凋落物中现存氮库增加而对生产力产生负反馈。
