Climate and lawn management interact to control C 4 plant distribution in residential lawns across seven U.S. cities
Climate and lawn management interact to control C 4 plant distribution in residential lawns across seven U.S. cities
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气候和草坪管理相互作用，控制美国七个城市住宅草坪中 C 4 植物的分布
DOI：
10.1002/eap.1884
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发表时间：
2019
影响因子：
5
通讯作者：
Hall, Sharon J.
中科院分区：
文献类型：
--
作者：
Trammell, Tara L.;Pataki, Diane E.;Still, Christopher J.;Ehleringer, James R.;Avolio, Meghan L.;Bettez, Neil;Cavender‐Bares, Jeannine;Groffman, Peter M.;Grove, Morgan;Hall, Sharon J.
在天然草地中，C4植物优势度随生长季温度的升高而增加，反映了C3与C4植物在植物生长速率和水分利用效率上的明显差异。C4光合途径。然而，在草坪中，管理决策影响种植的草坪草和杂草物种之间的相互作用，导致人类与气候对草坪物种分布的控制程度存在一定的不确定性。我们测量了美国七个城市的住宅草坪中草本植物碳同位素比值（δ 13 C，C3/C4相对丰度指数）和C4覆盖率，以确定气候，草坪植物管理或气候与植物管理之间的相互作用如何影响C4草坪覆盖率。我们还计算了理论C4碳增益预测的植物生理模型作为预期C4覆盖由于生长季节的气候条件在每个城市的指数。与理论预测相反，城市草坪中植物δ 13 C和C4覆盖度与年平均温度的相关性比与生长季温度的相关性更强。冬季温度的影响C4草坪草坪植物的分布，相反的自然生态系统，生长季节的温度主要驱动C4分布。在三个最温暖的城市，草坪中的C4覆盖率最高，这是由于气候和房主植物管理之间的相互作用（例如，种植C4草皮物种）。C4草坪植物种类所占比例与区域性草地植物群中C4植物种类所占比例相似。然而，大多数C4物种是非本地草坪草，而不是区域起源。虽然温度是美国各地草坪物种组成的强有力控制因素，但城市对于这些模式是否由种植的草坪草与杂草物种驱动存在差异。在一些城市，与杂草植物的生物相互作用似乎占主导地位，而在其他城市，C4植物主要是进口和种植。城市中CO2和温度升高会影响C3/C4竞争结果;然而，这项研究提供了气候和植物管理动态影响草坪中C3/C4植物的地理学和生态学的证据。它们不同的水和养分利用效率可能会对城市的碳、水、能源和养分预算产生重大影响。
In natural grasslands, C4plant dominance increases with growing season temperatures and reflects distinct differences in plant growth rates and water use efficiencies of C3vs. C4photosynthetic pathways. However, in lawns, management decisions influence interactions between planted turfgrass and weed species, leading to some uncertainty about the degree of human vs. climatic controls on lawn species distributions. We measured herbaceous plant carbon isotope ratios (δ13C, index of C3/C4relative abundance) and C4cover in residential lawns across seven U.S. cities to determine how climate, lawn plant management, or interactions between climate and plant management influenced C4lawn cover. We also calculated theoretical C4carbon gain predicted by a plant physiological model as an index of expected C4cover due to growing season climatic conditions in each city. Contrary to theoretical predictions, plant δ13C and C4cover in urban lawns were more strongly related to mean annual temperature than to growing season temperature. Wintertime temperatures influenced the distribution of C4lawn turf plants, contrary to natural ecosystems where growing season temperatures primarily drive C4distributions. C4cover in lawns was greatest in the three warmest cities, due to an interaction between climate and homeowner plant management (e.g., planting C4turf species) in these cities. The proportion of C4lawn species was similar to the proportion of C4species in the regional grass flora. However, the majority of C4species were nonnative turf grasses, and not of regional origin. While temperature was a strong control on lawn species composition across the United States, cities differed as to whether these patterns were driven by cultivated lawn grasses vs. weedy species. In some cities, biotic interactions with weedy plants appeared to dominate, while in other cities, C4plants were predominantly imported and cultivated. Elevated CO2and temperature in cities can influence C3/C4competitive outcomes; however, this study provides evidence that climate and plant management dynamics influence biogeography and ecology of C3/C4plants in lawns. Their differing water and nutrient use efficiency may have substantial impacts on carbon, water, energy, and nutrient budgets across cities.