Do plant-soil feedbacks promote coexistence in a sagebrush steppe?

Recent studies have shown the potential for negative plant-soil feedbacks (PSFs) to promote stable coexistence but have not quantified the stabilizing effect relative to other coexistence mechanisms. We conducted a field experiment to test the role of PSFs in stabilizing coexistence among four dominant sagebrush steppe species that appear to coexist stably, based on previous work with observational data and models. We then integrated the effects of PSF treatments on focal species across germination, survival, and first-year growth. To contribute to stable coexistence, soil microbes should have host-specific effects that result in negative feedbacks. Over two replicated growing seasons, our experiments consistently showed that soil microbes have negative effects on plant growth, but these effects were rarely host-specific. The uncommon host-specific effects were mostly positive at the germination stage and negative for growth. Integrated effects of PSF across early life-stage vital rates..., ,

近期研究表明，负向植物-土壤反馈（negative plant-soil feedbacks, PSFs）具备推动物种稳定共存的潜力，但尚未量化其相较于其他共存机制的稳定化效应。我们依托此前基于观测数据与模型完成的研究，开展了田间试验，以检验PSFs在四类稳定共存的优势蒿灌丛草原物种的共存稳定化过程中所发挥的作用。随后，我们整合了PSF处理对目标物种在萌发、存活以及一年生生长阶段的影响效应。若要助力实现稳定共存，土壤微生物需产生宿主特异性效应，进而形成负向反馈。在两个重复生长季的试验中，我们的研究结果始终表明，土壤微生物会对植物生长产生负向影响，但这类影响极少具备宿主特异性。为数不多的宿主特异性效应中，多数在萌发阶段呈正向影响，而对植物生长则产生负向影响。PSFs在植物早期生命阶段关键生命参数上的整合效应……