Jones M L M, Wallace H L, Norris D, Brittain S A, Haria S, Jones R E, Rhind P M, Reynolds B R, Emmett B A
Centre for Ecology and Hydrology Bangor, Orton Building, Deiniol Road, Bangor, Gwynedd LL57 2UP, UK.
Plant Biol (Stuttg). 2004 Sep;6(5):598-605. doi: 10.1055/s-2004-821004.
A field survey was conducted to detect signals of atmospheric nitrogen (N) in 11 dune systems along a nitrogen deposition gradient in the United Kingdom. In the mobile and semi-fixed dunes, above-ground biomass was positively related to N inputs. This increase was largely due to increased height and cover of Ammophila arenaria. In the long term, this increased biomass may lead to increased organic matter accumulation and consequently accelerated soil development. In the fixed dunes, above ground biomass also showed a positive relationship with N inputs as did soil C : N ratio while soil available N was negatively related to N inputs. Plant species richness was negatively related to N inputs. In the dune slacks, while soil and bulk vegetation parameters showed no relationship with N inputs, cover of Carex arenaria and Hypochaeris radicata increased. Site mean Ellenberg N numbers showed no relationship with N deposition either within habitats or across the whole dataset. Neither abundance-weighting nor inclusion of the Siebel numbers for bryophytes improved the relationship. The survey reveals that the relationships of soil and vegetation with atmospheric N deposition vary between sand dune habitats but, despite this variability, clear correlations with N inputs exist. While this survey cannot establish causality, on the basis of the relationships observed we suggest a critical load range of 10 - 20 kg N ha(-1) yr(-1) for coastal sand dunes in the UK.
在英国，沿着氮沉降梯度对11个沙丘系统进行了实地调查，以检测大气氮（N）信号。在流动沙丘和半固定沙丘中，地上生物量与氮输入呈正相关。这种增加主要是由于沙滨麦草的高度和覆盖度增加。从长期来看，生物量的增加可能导致有机质积累增加，从而加速土壤发育。在固定沙丘中，地上生物量也与氮输入呈正相关，土壤碳氮比也是如此，而土壤有效氮与氮输入呈负相关。植物物种丰富度与氮输入呈负相关。在沙丘低地，虽然土壤和整体植被参数与氮输入没有关系，但砂苔草和黄鹌菜的覆盖度增加了。在栖息地内部或整个数据集中，地点平均埃伦贝格氮指标与氮沉降均无关系。苔藓植物的丰度加权或包含西贝尔指数均未改善这种关系。调查表明，土壤和植被与大气氮沉降的关系在沙丘栖息地之间有所不同，但尽管存在这种变异性，与氮输入仍存在明显的相关性。虽然这项调查无法确定因果关系，但根据观察到的关系，我们建议英国沿海沙丘的临界负荷范围为10 - 20千克氮/公顷·年。
