Shanghai Key Laboratory for Ecological Processes and Restoration in Urban Areas, Department of Environmental Sciences, East China Normal University, Shanghai, 200062, China.
Oecologia. 2014 Mar;174(3):993-1005. doi: 10.1007/s00442-013-2816-3. Epub 2013 Nov 26.
Following studies that showed negative effects of species loss on ecosystem functioning, newer studies have started to investigate if similar consequences could result from reductions of genetic diversity within species. We tested the influence of genotypic richness and dissimilarity (plots containing one, three, six or 12 genotypes) in stands of the invasive plant Solidago canadensis in China on the decomposition of its leaf litter and associated soil animals over five monthly time intervals. We found that the logarithm of genotypic richness was positively linearly related to mass loss of C, N and P from the litter and to richness and abundance of soil animals on the litter samples. The mixing proportion of litter from two sites, but not genotypic dissimilarity of mixtures, had additional effects on measured variables. The litter diversity effects on soil animals were particularly strong under the most stressful conditions of hot weather in July: at this time richness and abundance of soil animals were higher in 12-genotype litter mixtures than even in the highest corresponding one-genotype litter. The litter diversity effects on decomposition were in part mediated by soil animals: the abundance of Acarina, when used as covariate in the analysis, fully explained the litter diversity effects on mass loss of N and P. Overall, our study shows that high genotypic richness of S. canadensis leaf litter positively affects richness and abundance of soil animals, which in turn accelerate litter decomposition and P release from litter.
继表明物种丧失对生态系统功能产生负面影响的研究之后，新的研究开始调查物种遗传多样性减少是否会产生类似的后果。我们在中国对入侵植物加拿大一枝黄花（Solidago canadensis）的林分中，测试了基因型丰富度和差异（每个林分包含一个、三个、六个或 12 个基因型）对其叶片凋落物分解和相关土壤动物的影响，共进行了五个月的时间间隔。我们发现，基因型丰富度的对数与凋落物中 C、N 和 P 的质量损失以及凋落物样本中土壤动物的丰富度和丰度呈正线性相关。两个地点的凋落物混合比例，但不是混合物的基因型差异，对测量变量有额外的影响。在 7 月炎热天气的最恶劣条件下，凋落物多样性对土壤动物的影响尤其强烈：在这个时候，12 个基因型混合凋落物中的土壤动物的丰富度和丰度甚至高于最高的一个基因型凋落物。凋落物多样性对分解的影响部分是通过土壤动物介导的：当在分析中用作协变量时，节肢动物的丰度完全解释了凋落物多样性对 N 和 P 质量损失的影响。总体而言，我们的研究表明，加拿大一枝黄花叶片凋落物的高基因型丰富度会积极影响土壤动物的丰富度和丰度，而土壤动物反过来又会加速凋落物分解和 P 从凋落物中的释放。
