Effects of nitrogen addition on successional dynamics and species diversity in Michigan old-fields
Effects of nitrogen addition on successional dynamics and species diversity in Michigan old-fields
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DOI：
10.1046/j.1365-2745.1998.8650794.x
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发表时间：
1998-10-01
影响因子：
5.5
通讯作者：
Miller, CJ
中科院分区：
文献类型：
--
作者：
Huberty, LE;Gross, KL;Miller, CJ
1我们研究了氮添加对早期演替动态和植物物种多样性的影响，在美国密歇根州西南部的一个旧的领域的继承治疗重复样地，7年后放弃农业。2氮添加显着增加地上植物生物量，但没有影响不同的生活史组的位移或持久性。一年生物种组成了类似的比例的社区生物量和减少在控制和氮添加微区的等效速率。多年生植物的生物量增加在控制和氮添加microplot.3一年生植物占主导地位的最初，但在丰富的前4年下降，并取代了两年生植物，然后草本多年生植物。由此产生的高数量的物种损失和收益不受氮添加。4氮添加不影响平均物种密度或香农多样性指数。也没有时间变化的控制和氮添加微区之间的物种组成的相似性，表明氮添加并没有引起分歧，随着时间的推移，在社区组成。在第7年，相似的物种占主导地位的氮添加和控制小区，但有不同的物种组成和丰富的下属物种在每个社区。5只有在本研究的第6年，有一个显着的负相关关系，群落生物量和香农多样性指数。有没有显着的关系，群落生物量和物种密度在任何的前7年后放弃。因此，由于氮添加增加生物量的社会反应主要是通过社区结构的变化，而不是丰富度。6氮添加对早期演替动态，物种组成和植物群落的多样性的影响可能取决于初始的现场条件。在像我们这样的土壤肥沃的地方，对氮富集的反应可能较慢，这些土壤主要是多年生草本双子叶植物。
1 We examined the impact of nitrogen addition on early successional dynamics and plant species diversity in replicate plots of an old-field succession treatment in south-western Michigan, USA, for 7 years following abandonment from agriculture.2 Nitrogen addition significantly increased above-ground plant biomass, but had no effect on the displacement or persistence of different life-history groups. Annual species made up a similar proportion of community biomass and decreased at equivalent rates in control and nitrogen-addition microplots. Perennial species biomass increased at similar rates in the control and nitrogen-addition microplots.3 Annual species dominated initially, but declined in abundance over the first 4 years and were replaced by biennials and then herbaceous perennials. The resulting high numbers of species losses and gains were not affected by nitrogen addition.4 Nitrogen addition did not affect mean species density or the Shannon index of diversity. There was also no temporal change in the similarity of species composition between control and nitrogen-addition microplots, indicating that nitrogen addition did not cause divergence over time in community composition. In year 7, similar species dominated the nitrogen-addition and control microplots, but there were differences in species composition and abundance of the subordinate species in each community.5 Only in year 6 of this study was there a significant negative relationship between community biomass and the Shannon diversity index. There was no significant relationship between community biomass and species density in any of the first 7 years following abandonment. Thus, the community response to increased biomass due to nitrogen addition was expressed primarily through changes in community structure, not richness.6 The effects of nitrogen addition on the early successional dynamics, species composition and consequently diversity of a plant community may depend on initial site conditions. The response to nitrogen enrichment may be slower in sites such as ours with fertile soils that become dominated by herbaceous perennial dicots.