Lee Mark A, Manning Pete, Walker Catherine S, Power Sally A
Division of Ecology and Evolution, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY, UK,
Oecologia. 2014 Dec;176(4):1173-85. doi: 10.1007/s00442-014-3077-5. Epub 2014 Sep 16.
Grasslands provide many ecosystem services including carbon storage, biodiversity preservation and livestock forage production. These ecosystem services will change in the future in response to multiple global environmental changes, including climate change and increased nitrogen inputs. We conducted an experimental study over 3 years in a mesotrophic grassland ecosystem in southern England. We aimed to expose plots to rainfall manipulation that simulated IPCC 4th Assessment projections for 2100 (+15% winter rainfall and -30% summer rainfall) or ambient climate, achieving +15% winter rainfall and -39% summer rainfall in rainfall-manipulated plots. Nitrogen (40 kg ha(-1) year(-1)) was also added to half of the experimental plots in factorial combination. Plant species composition and above ground biomass were not affected by rainfall in the first 2 years and the plant community did not respond to nitrogen enrichment throughout the experiment. In the third year, above-ground plant biomass declined in rainfall-manipulated plots, driven by a decline in the abundances of grass species characteristic of moist soils. Declining plant biomass was also associated with changes to arthropod communities, with lower abundances of plant-feeding Auchenorrhyncha and carnivorous Araneae indicating multi-trophic responses to rainfall manipulation. Plant and arthropod community composition and plant biomass responses to rainfall manipulation were not modified by nitrogen enrichment, which was not expected, but may have resulted from prior nitrogen saturation and/or phosphorus limitation. Overall, our study demonstrates that climate change may in future influence plant productivity and induce multi-trophic responses in grasslands.
草原提供多种生态系统服务，包括碳储存、生物多样性保护和牲畜饲料生产。这些生态系统服务未来将因多种全球环境变化而改变，包括气候变化和氮输入增加。我们在英格兰南部的一个中营养草原生态系统中进行了为期3年的实验研究。我们的目标是让样地接受模拟政府间气候变化专门委员会（IPCC）对2100年预测的降雨处理（冬季降雨增加15%，夏季降雨减少30%）或当前气候条件，在降雨处理样地实现冬季降雨增加15%，夏季降雨减少39%。氮（40千克·公顷⁻¹·年⁻¹）也以析因组合的方式添加到一半的实验样地中。在最初两年，植物物种组成和地上生物量不受降雨影响，并且在整个实验过程中植物群落对氮富集没有反应。在第三年，降雨处理样地的地上植物生物量下降，这是由湿土特征的禾本科物种丰度下降所驱动。植物生物量下降还与节肢动物群落的变化有关，植食性叶蝉和肉食性蜘蛛的丰度降低表明对降雨处理有多个营养级的响应。植物和节肢动物群落组成以及植物生物量对降雨处理的响应未因氮富集而改变，这是出乎意料的，但可能是由于先前的氮饱和和/或磷限制所致。总体而言，我们的研究表明，气候变化未来可能会影响草原的植物生产力并引发多个营养级的响应。
