物种定居顺序影响多样性的互补与抽样效应：基于藻类群落的实验研究
物种定居顺序可能会决定群落的结构，并因此影响物种多样性与生态系统功能的关系。地表过程与资源生态国家重点实验室张全国、张大勇等人，使用6种淡水绿藻进行的实验表明：当群落包含有高产物种时其结构不受物种定居顺序影响（高产物种无论是初始定居还是较晚到达都会最终占据竞争优势），但是由产量相似物种组成的群落其结构容易受到物种定居顺序的影响（初始定居的物种容易获得竞争优势）；以 高产物种为初始定居者的群落有更强的抽样效应，而初始定居者为低产物种的群落有更强的互补效应。混作群落是否高产主要取决于抽样效应——高产物种作为初始 定居者的群落比单作群落高产，而具有相反定居顺序的群落和单作群落产量没有区别。这项工作表明人们在预测物种多样性与生态功能关系的时候需要将物种迁入历 史考虑在内。
Colonization sequence influences selection and complementarity effects on biomass production in experimental algal microcosms
Quan-Guo Zhang and Da-Yong Zhang
Species extinction and immigration both are common in natural communities and the sequence with which species are lost from or added to communities may be crucial to community structure. We experimentally addressed this issue by growing six green algal species in monocultures and all possible 2-species mixtures, with two colonization sequences for each mixture. Both convergence and divergence in community structure were observed. The compositions containing particularly productive species were more likely to converge, while those comprising of species with similar monoculture yields were more likely to diverge. The species mixtures with high-yielding initial and low-yielding invading species produced more biomass than monocultures, but mixtures with the opposite assembly order produced only the same level of biomass as monocultures did. To address the diversity-ecosystem functioning issue, we estimate complementarity effect by relative yield total (RYT) and selection effect by the correlation between species’ monoculture yields and their relative yields in mixtures, respectively. We found overall negative complementarity and positive selection effect in mixtures with high-yielding species as initial colonizers, but positive complementarity and negative selection effect in mixtures with low-yielding initial species. Nonetheless, because we used only up to two species in each microcosm, our results are limited in addressing the relationship between species diversity and ecosystem functioning. Future research should study the effects of immigration history with many more species involved in community assembly.
Oikos, 116, 1748-1758, 2007
http://www3.interscience.wiley.com/journal/118531722/abstract?CRETRY=1&SRETRY=0
Figure. Complementarity effect, measured as relative yield total, of two types of assemblages with opposite colonization orders over time. ‘Productive-unproductive assemblages’ means those in which high-yielding species as initial colonizers and low-yielding species as late arrivals. A horizontal dashed line through one shows the null hypothesis that no overyielding occurs. Asterisks indicate significant departure from the null hypothesis.
