Centre for Hydrological and Ecosystem Science, Department of Geography, Loughborough University, Loughborough LE11 3TU, UK.
Centre for Hydrological and Ecosystem Science, Department of Geography, Loughborough University, Loughborough LE11 3TU, UK.
Sci Total Environ. 2015 Apr 15;512-513:631-636. doi: 10.1016/j.scitotenv.2015.01.067. Epub 2015 Feb 3.
Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant-prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific.
氮（N）沉降对自然和半自然生态系统有重要的负面影响，影响着营养级间的生物相互作用。低养分系统对 N 输入的变化特别敏感，因此更容易受到 N 沉降的影响。肉食植物通常是这些生态系统的一部分，部分原因是它们从猎物中获得了额外的营养。我们研究了 N 沉降对欧洲 16 个寡营养沼泽中生长的肉食植物圆叶茅膏菜的营养的影响。我们使用自然丰度稳定同位素方法测量了组织 N、磷（P）和钾（K）浓度以及猎物和根 N 吸收。我们的目的是测试 N 沉降对 D. rotundifolia 猎物和根 N 吸收以及养分化学计量的影响。D. rotundifolia 根 N 吸收受 N 沉降的强烈影响，可能导致 N 限制减少。猎物 N 对 D. rotundifolia 中所含 N 的贡献范围为 20%至 60%。N 沉降减少了来自猎物的最大 N 量，但在这一最大值以下，这种情况有所不同。D. rotundifolia 组织 N 浓度是根 N 供应和猎物 N 吸收的共同产物。增加的猎物 N 吸收与组织 P 浓度的增加相关，表明从猎物中吸收 P。因此，N 沉降降低了肉食植物-猎物相互作用的强度，导致营养级间的养分转移减少。我们认为，N 沉降对 D. rotundifolia 有负面影响，对 N 沉降的反应可能具有强烈的特定地点特征。
