1 Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University , Nanjing 210095 , Jiangsu, People's Republic of China.
2 Institute for Environmental Biology, Ecology and Biodiversity, Utrecht University , Padualaan 8, 3584 CH Utrecht , The Netherlands.
Proc Biol Sci. 2018 Dec 19;285(1893):20182035. doi: 10.1098/rspb.2018.2035.
Diversity-invasion resistance relationships are often variable and sensitive to environmental conditions such as resource availability. Resource stoichiometry, the relative concentration of different elements in the environment, has been shown to have strong effects on the physiology and interactions between different species. Yet, its role for diversity-invasion resistance relationships is still poorly understood. Here, we explored how the ratio of nitrogen (N) and phosphorus affects the productivity and invasion resistance of constructed microbial communities by a plant pathogenic bacterium, Ralstonia solanacearum. We found that resource stoichiometry and species identity effects affected the invasion resistance of communities. Both high N concentration and resident community diversity constrained invasions, and two resident species, in particular, had strong negative effects on the relative density of the invader and the resident community productivity. While resource stoichiometry did not affect the mean productivity of the resident community, it favoured the growth of two species that strongly constrained invasions turning the slope of productivity-invasion resistance relationship more negative. Together our findings suggest that alterations in resource stoichiometry can change the community resistance to invasions by having disproportionate effects on species growth, potentially explaining changes in microbial community composition under eutrophication.
多样性-入侵抗性关系通常是可变的，并对环境条件（如资源可用性）敏感。资源化学计量学，即环境中不同元素的相对浓度，已被证明对不同物种的生理和相互作用有很强的影响。然而，其对多样性-入侵抗性关系的作用仍知之甚少。在这里，我们探讨了氮（N）和磷的比例如何影响植物病原菌丁香假单胞菌构建的微生物群落的生产力和入侵抗性。我们发现，资源化学计量学和物种身份的影响影响了群落的入侵抗性。高氮浓度和居民社区的多样性都限制了入侵，而且两个居民物种，特别是，对入侵者的相对密度和居民社区生产力有很强的负面影响。虽然资源化学计量学没有影响居民社区的平均生产力，但它有利于两种生长强烈限制入侵的物种，使生产力-入侵抗性关系的斜率更负。总之，我们的研究结果表明，资源化学计量学的改变可以通过对物种生长产生不成比例的影响来改变群落对入侵的抗性，这可能解释了富营养化下微生物群落组成的变化。
