Measured estimates of semi-natural terrestrial NPP in Great Britain: comparison with modelled values, and dependence on atmospheric nitrogen deposition
Measured estimates of semi-natural terrestrial NPP in Great Britain: comparison with modelled values, and dependence on atmospheric nitrogen deposition
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DOI：
10.1007/s10533-019-00582-5
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发表时间：
2019-07
期刊：
影响因子：
4
通讯作者：
E. Tipping;J. Davies;P. Henrys;S. Jarvis;E. Rowe;S. Smart;M. Le Duc;R. Marrs;R. Pakeman
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文献类型：
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作者：
E. Tipping;J. Davies;P. Henrys;S. Jarvis;E. Rowe;S. Smart;M. Le Duc;R. Marrs;R. Pakeman
氮（N）有限，未施肥的陆地生态系统中的植物生长应响应大气沉积（Ndep）的额外N输入。我们通过汇编1932-2014年期间测量的生物量生产的796个净初级生产力（NPP）估计值，对英国（GB）的站点进行了调查，尽管大多数是1990年以后的。这些地点的植被主要是灌木、草和蕨，Ndep的范围很广（2000年为0.5-3.3 gN m−2a− 1）。测量的NPP估计值进行了比较，从地球化学生态系统模型N14 CP，预测NPP强烈依赖于Ndep的计算值。所有数据的实测和模拟总NPP平均值（gC m−2a−1）分别为387（标准差，SD = 193）和377（SD = 72）。植被类型的测量和建模平均值遵循以下顺序：阔叶树~针叶树>草本植物（粗糙草地+蕨菜）~灌木。在对单个模型网格单元（5 km × 5 km）中站点的测量值进行10次或更多次重复计算后，NPP测量值和模拟值相关（n = 26，r2= 0.22，p = 0.011），斜率接近1。草本植物（n = 298，p = 0.021）和灌木（n = 473，p = 0.006）的ln NPP和累积Ndeps之间存在显著的线性关系，斜率与模型预测的斜率相当。结果表明，在GB的半自然NPP积极依赖于Ndep，在一定程度上同意与N14 CP预测定量。该模型的计算，使用Ndep的模拟时间变化，表明Ndep施肥导致半天然NPP平均增加30%的灌木，草本植物71%，阔叶树91%，在1800年至2010年期间。结合以前发表的森林结果，我们的研究结果表明，Ndep施肥的一般和广泛的植被反应。
Plant growth in nitrogen (N)-limited, unfertilised terrestrial ecosystems should respond to additional N inputs from atmospheric deposition (Ndep). We investigated this for sites in Great Britain (GB) by compiling 796 estimates of net primary productivity (NPP) from measured biomass production over the period 1932–2014, although the great majority were for 1990 onwards. The sites were largely vegetated with shrubs, grass and bracken, and had a wide range of Ndep(0.5–3.3 gN m−2a−1in 2000). The measured NPP estimates were compared with calculated values from the biogeochemical ecosystem model N14CP, which predicts that NPP depends strongly upon Ndep. The measured and modelled average total NPP values (gC m−2a−1) from all data were 387 (standard deviation, SD = 193) and 377 (SD = 72) respectively. Measured and modelled averages for vegetation classes followed the sequence: broadleaved trees ~ needle-leaved trees > herbs (rough grassland + bracken) ~ shrubs. After averaging measured values for sites in individual model grid cells (5 km × 5 km) with 10 or more replicates, the measured and modelled NPP values were correlated (n = 26, r2= 0.22, p = 0.011), with a slope close to unity. Significant linear relationships were found between measured ln NPP and cumulative Ndepfor both herbs (n = 298, p = 0.021) and shrubs (n = 473, p = 0.006), with slopes comparable to those predicted with the model. The results suggest that semi-natural NPP in GB depends positively upon Ndep, in a manner that agrees quantitatively with N14CP predictions. Calculations with the model, using modelled temporal variation in Ndep, indicate that fertilisation by Ndepcaused average increases in semi-natural NPP over the period 1800 to 2010 of 30% for shrubs, 71% for herbs, and 91% for broadleaved trees. Combined with previous published results for forests, our findings suggest a general and widespread vegetation response to fertilisation by Ndep.