Evidence for differential effects of reduced and oxidised nitrogen deposition on vegetation independent of nitrogen load.
Evidence for differential effects of reduced and oxidised nitrogen deposition on vegetation independent of nitrogen load.
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DOI：
10.1016/j.envpol.2015.09.017
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发表时间：
2016
影响因子：
8.9
通讯作者：
L. V. D. van den Berg;L. Jones;L. Sheppard;S. Smart;R. Bobbink;N. Dise;M. Ashmore
中科院分区：
文献类型：
--
作者：
L. V. D. van den Berg;L. Jones;L. Sheppard;S. Smart;R. Bobbink;N. Dise;M. Ashmore
氮(N)沉积影响全球自然和半自然生态系统。然而，不同生境的植被对氮沉降的响应可能有很大的不同，并且可能通过氮的形式来调节。尽管人们对总氮沉降的影响已经引起了很大的关注，但与总氮沉降无关的还原和氧化氮的影响却没有得到太多的关注。在本文中，我们提出了对英国国家监测数据的新分析，以提供对八种生境类型(酸性、石灰性和中养性草原、高地和低地石南、沼泽和沼泽、富碱沼泽和林地)减少和氧化N沉积的影响是否存在差异的广泛评估。我们分析了2007年英国农村调查中6860个样地的数据，分析了总氮沉降量和氮形态对物种丰富度、Ellenberg N值和草/草比的影响。我们的结果提供了明确的证据，在排除了相关的解释变量(气候和硫沉积)后，氮沉积影响了除富碱沼泽以外的所有生境的物种丰富度。此外，氮在沉积物中的形态似乎对草地和林地的生物多样性很重要，但对沼泽和石南地区的生物多样性并不重要。除一种生境类型外，所有生境类型中，Ellenberg N与NHx沉降的关系都比与NOx沉降有关的增加更多。物种丰富度与氮素形态的关系因生境而异：酸性草地和中营养草地对NHx沉降更敏感，而石灰性草地和林地对NOx沉降更敏感。这些关系可能是由组成植物物种对氧化或还原形式的N的偏好所驱动的，而不是由土壤酸化所驱动的。
Nitrogen (N) deposition impacts natural and semi-natural ecosystems globally. The responses of vegetation to N deposition may, however, differ strongly between habitats and may be mediated by the form of N. Although much attention has been focused on the impact of total N deposition, the effects of reduced and oxidised N, independent of the total N deposition, have received less attention. In this paper, we present new analyses of national monitoring data in the UK to provide an extensive evaluation of whether there are differences in the effects of reduced and oxidised N deposition across eight habitat types (acid, calcareous and mesotrophic grasslands, upland and lowland heaths, bogs and mires, base-rich mires, woodlands). We analysed data from 6860 plots in the British Countryside Survey 2007 for effects of total N deposition and N form on species richness, Ellenberg N values and grass:forb ratio. Our results provide clear evidence that N deposition affects species richness in all habitats except base-rich mires, after factoring out correlated explanatory variables (climate and sulphur deposition). In addition, the form of N in deposition appears important for the biodiversity of grasslands and woodlands but not mires and heaths. Ellenberg N increased more in relation to NHxdeposition than NOydeposition in all but one habitat type. Relationships between species richness and N form were habitat-specific: acid and mesotrophic grasslands appear more sensitive to NHxdeposition while calcareous grasslands and woodlands appeared more responsive to NOydeposition. These relationships are likely driven by the preferences of the component plant species for oxidised or reduced forms of N, rather than by soil acidification.