DRI-Grass: A New Experimental Platform for Addressing Grassland Ecosystem Responses to Future Precipitation Scenarios in South-East Australia.
DRI-Grass: A New Experimental Platform for Addressing Grassland Ecosystem Responses to Future Precipitation Scenarios in South-East Australia.
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DOI：
10.3389/fpls.2016.01373
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发表时间：
2016
影响因子：
5.6
通讯作者：
Johnson SN
中科院分区：
文献类型：
--
作者：
Power SA;Barnett KL;Ochoa-Hueso R;Facey SL;Gibson-Forty EV;Hartley SE;Nielsen UN;Tissue DT;Johnson SN
气候模型预测降雨量、频率和季节性的变化。鉴于草原生产力和降雨量之间的密切联系，这种变化很可能对草原生态系统的功能产生深远影响，并改变物种之间的相互作用。在这里，我们介绍一个独特的，新的实验平台- DRI-Grass（干旱和根草食动物在草原的相互作用）-暴露在澳大利亚东南部草原的五个降雨制度[环境（AMB），增加量（IA，+50%），减少金额（RA，-50%），频率降低（RF，每21天一次降雨，总量不变）和夏季干旱（SD，12-14周无水，12月至3月）]，和对比水平的根食草动物。地下食草动物（根食金龟子）除了治疗允许新的调查改变降雨和根食草动物的双应力的生态反应。我们通过与室外小区的比较，量化了永久安装的避雨亭对小气候的影响，确定了小避雨亭对气温（白天-0.19 ° C，夜间+0.26 ° C），土壤含水量（SWC; -8%）和光合有效辐射（PAR; -16%）的影响。庇护所与净初级生产力（NPP）的适度增加，特别是在凉爽的季节。降雨处理产生了很大的差异，在SWC，与IA例外;后者可能是由于较高的蒸腾速率与更大的植物生物量在IA和低持水能力的排水良好，桑迪土壤相结合。生长季NPP强烈减少SD，但没有响应其他降雨处理。此外，根草食动物没有影响植物生物量，有没有草食动物和降雨处理在第一年的研究之间的相互作用。根草食动物，但是，诱导叶片硅为基础的防御狗牙根和画眉草curvula。恢复供水后，在SD地块的NPP快速恢复表明高功能的恢复力在网站上，并可能反映了适应历史上高的降雨量变化，无论是在年内和年之间的植被。DRI-Grass提供了一个独特的平台，可以了解生态相互作用如何受到降雨状况变化的影响，特别是地下食草动物如何改变草原对极端气候的抵抗力和恢复力。
Climate models predict shifts in the amount, frequency and seasonality of rainfall. Given close links between grassland productivity and rainfall, such changes are likely to have profound effects on the functioning of grassland ecosystems and modify species interactions. Here, we introduce a unique, new experimental platform – DRI-Grass (Drought and Root Herbivore Interactions in a Grassland) – that exposes a south-eastern Australian grassland to five rainfall regimes [Ambient (AMB), increased amount (IA, +50%), reduced amount (RA, -50%), reduced frequency (RF, single rainfall event every 21 days, with total amount unchanged) and summer drought (SD, 12–14 weeks without water, December–March)], and contrasting levels of root herbivory. Incorporation of a belowground herbivore (root-feeding scarabs) addition treatment allows novel investigation of ecological responses to the twin stresses of altered rainfall and root herbivory. We quantified effects of permanently installed rain shelters on microclimate by comparison with outside plots, identifying small shelter effects on air temperature (-0.19°C day, +0.26°C night), soil water content (SWC; -8%) and photosynthetically active radiation (PAR; -16%). Shelters were associated with modest increases in net primary productivity (NPP), particularly during the cool season. Rainfall treatments generated substantial differences in SWC, with the exception of IA; the latter is likely due to a combination of higher transpiration rates associated with greater plant biomass in IA and the low water-holding capacity of the well-drained, sandy soil. Growing season NPP was strongly reduced by SD, but did not respond to the other rainfall treatments. Addition of root herbivores did not affect plant biomass and there were no interactions between herbivory and rainfall treatments in the 1st year of study. Root herbivory did, however, induce foliar silicon-based defenses in Cynodon dactylon and Eragrostis curvula. Rapid recovery of NPP following resumption of watering in SD plots indicates high functional resilience at the site, and may reflect adaptation of the vegetation to historically high variability in rainfall, both within- and between years. DRI-Grass provides a unique platform for understanding how ecological interactions will be affected by changing rainfall regimes and, specifically, how belowground herbivory modifies grassland resistance and resilience to climate extremes.
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