Remke Eva, Brouwer Emiel, Kooijman Annemieke, Blindow Irmgard, Esselink Hans, Roelofs Jan G M
Biological Station of Hiddensee, Ernst-Moritz-Arndt University Greifswald, Biologenweg 15, 18565 Kloster, Germany.
Environ Pollut. 2009 Mar;157(3):792-800. doi: 10.1016/j.envpol.2008.11.020. Epub 2008 Dec 17.
Coastal dunes around the Baltic Sea have received small amounts of atmospheric nitrogen and are rather pristine ecosystems in this respect. In 19 investigated dune sites the atmospheric wet nitrogen deposition is 3-8kg Nha(-1)yr(-1). The nitrogen content of Cladonia portentosa appeared to be a suitable biomonitor of these low to medium deposition levels. Comparison with EMEP-deposition data showed that Cladonia reflects the deposition history of the last 3-6 years. With increasing nitrogen load, we observed a shift from lichen-rich short grass vegetation towards species-poor vegetation dominated by the tall graminoid Carex arenaria. Plant species richness per field site, however, does not decrease directly with these low to medium N deposition loads, but with change in vegetation composition. Critical loads for acidic, dry coastal dunes might be lower than previously thought, in the range of 4-6kg Nha(-1)yr(-1) wet deposition.
波罗的海周边的海岸沙丘接收的大气氮含量较少，在这方面是相当原始的生态系统。在19个被调查的沙丘地点，大气湿氮沉降量为3 - 8千克氮每公顷每年。枝状石蕊的氮含量似乎是这些中低沉降水平的合适生物监测指标。与欧洲中期天气预报中心（EMEP）的沉降数据比较表明，枝状石蕊反映了过去3至6年的沉降历史。随着氮负荷增加，我们观察到从富含地衣的矮草植被向以高大禾本科植物砂苔草为主的物种贫乏植被转变。然而，每个田地的植物物种丰富度并非直接随着这些中低氮沉降负荷而降低，而是随着植被组成的变化而降低。酸性干燥海岸沙丘的临界负荷可能比之前认为的要低，在4 - 6千克氮每公顷每年湿沉降的范围内。
