Soil microbes weaken the positive effect of an aquatic–terrestrial subsidy on plant performance
Soil microbes weaken the positive effect of an aquatic–terrestrial subsidy on plant performance
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DOI：
10.1093/jpe/rtaa079
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发表时间：
2020-11
影响因子：
2.7
通讯作者：
Alejandra García;Hannah Locke;K. Crawford
中科院分区：
文献类型：
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作者：
Alejandra García;Hannah Locke;K. Crawford
通过水生-陆生补贴形成的联系可在构建社区和调节生态系统功能方面发挥重要作用。水-陆补贴在营养贫乏的生态系统中可能特别重要，例如密歇根湖周围的淡水沙丘。春天，成年的摇蚊从密歇根湖出现，成群结队地交配和死亡。它们的尸体在植物基部形成土丘，在那里它们可以通过营养投入提高植物的生产力。然而，水生-陆生补贴对植物生产力的影响可能取决于其他生物相互作用。特别是，土壤微生物可能在促进养分转化为植物可用形式或与植物竞争养分方面发挥关键作用。在一个温室实验中，我们测试了如何尸体从湖紧急摇蚊（摇蚊科）和土壤微生物独立和交互影响的表现，一个共同的沙丘草，Calamovilfa longifolia。为了确定是否蠓影响非生物土壤特性，我们测量了蠓添加如何影响土壤养分和土壤水分。蠓大大增加了植物的生物量，而土壤微生物影响这种效果的大小。在没有土壤微生物的情况下，有吸浆虫的植物生物量是没有吸浆虫的7倍。然而，在土壤微生物存在的情况下，植物生物量仅增加三倍。蠓的影响可能是由它们向土壤中的营养输入驱动的，因为蠓含有比沙丘土壤多100倍的N，多10倍的P和多150倍的K。我们的研究结果表明，土壤微生物可能与植物竞争这些营养物质。总之，我们发现，摇蚊可以是一个重要的水生-陆生补贴，产生强大的，积极的影响植物生产力沿着密歇根湖的海岸线，但水生-陆生补贴的影响，必须考虑在生态群落内发生的复杂的相互作用的背景下。
Linkages formed through aquatic–terrestrial subsidies can play an important role in structuring communities and mediating ecosystem functions. Aquatic–terrestrial subsidies may be especially important in nutrient-poor ecosystems, such as the freshwater sand dunes surrounding Lake Michigan. Adult midges emerge from Lake Michigan in the spring, swarm to mate and die. Their carcasses form mounds at the base of plants, where they may increase plant productivity through their nutrient inputs. However, the effect of aquatic–terrestrial subsidies on plant productivity could depend on other biotic interactions. In particular, soil microbes might play a key role in facilitating the conversion of nutrients to plant-available forms or competing for the nutrients with plants. In a greenhouse experiment, we tested how carcasses from lake emergent midges (Chironomidae) and soil microbes independently and interactively influenced the performance of a common dune grass, Calamovilfa longifolia. To determine whether midges influenced abiotic soil properties, we measured how midge additions influenced soil nutrients and soil moisture. Midges greatly increased plant biomass, while soil microbes influenced the magnitude of this effect. In the absence of soil microbes plant biomass was seven times greater with midges than without midges. However, in the presence of soil microbes, plant biomass was only three times greater. The effect of midges might be driven by their nutrient inputs into the soil, as midges contained 100 times more N, 10 times more P and 150 times more K than dune soils did. Our results suggest that soil microbes may be competing with plants for these nutrients. In sum, we found that midges can be an important aquatic–terrestrial subsidy that produces strong, positive effects on plant productivity along the shorelines of Lake Michigan, but that the impact of aquatic–terrestrial subsidies must be considered within the context of the complex interactions that take place within ecological communities.