Fertilization studies have elucidated basic principles of the role of nutrients in shaping plant communities and demonstrated the potential effects of anthropogenic nutrient deposition. Yet less is known about how these effects are mediated by interacting ecological factors, particularly in nutrient‐poor wetland habitats. In a long‐term experiment in a coastal plain wetland, we examined how fertilization and mowing affected the diversity and composition of a plant community as it reestablished after major disturbance. A drainage ditch in proximity to the experimental plots allowed us also to consider the influence of hydrology and its interactions with nutrient addition. Fertilization decreased species richness, with wetland specialist species showing especially great losses, and several lines of evidence suggest that the effect was mediated by competition for light. Altered hydrology via ditch drainage had effects that were similar to fertilization, with more rapidly draining plots showing lower diversity and decreased abundance of wetland species. Plant community diversity and dynamics were influenced by complex interactions between fertilization, disturbance, and hydrology. The negative effect of fertilization on species richness was initially mitigated by mowing, but in later years was more evident in mowed than in unmowed plots. In the absence of disturbance, nutrient addition increased the rate of transition to primarily woody communities. Similarly, drained plots experienced increased rates of succession compared to wetter plots. Our results suggest that these interactions need to be considered to understand the potential effects of anthropogenic nutrient addition and hydrologic alterations to wetland ecosystems.

中文翻译：

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长期养分富集，割草和沟渠排水在湿地植物群落的动态中相互作用

施肥研究阐明了养分在塑造植物群落中的作用的基本原理，并证明了人为养分沉积的潜在影响。然而，人们对相互作用的生态因素如何介导这些影响的了解还很少，特别是在营养贫乏的湿地生境中。在沿海平原湿地的一项长期实验中，我们研究了施肥和割草如何影响植物群落的多样性和组成，因为植物群落在受到严重干扰后得以重新建立。靠近实验区的排水沟使我们也可以考虑水文的影响及其与养分添加的相互作用。施肥减少了物种丰富度，其中湿地专业物种的损失尤为严重，有几条证据表明，这种影响是由对光的竞争介导的。通过沟渠排水改变水文状况的影响与施肥相似，排水更快的地块显示出较低的多样性和湿地物种的减少。施肥，干扰和水文学之间的复杂相互作用影响着植物群落的多样性和动态。最初通过割草减轻了施肥对物种丰富度的负面影响，但在后来的几年中，割草比未割草的土地更为明显。在没有干扰的情况下，添加养分增加了向主要为木本群落过渡的速度。同样，与湿润地块相比，排水地块的继承率增加。