Belowground Meristem Populations as Regulators of Grassland Dynamics

植物种群的研究对于将生物特征与生态系统功能联系起来，以及了解生态系统对气候变化的反应和生物多样性模式至关重要。 在多年生草地和其他植物群落中，地下分生组织（芽库）种群在当地植物种群的持续性和动态中起着重要作用，也可能决定群落的多样性，稳定性和入侵性。 在生态系统水平上，芽库和分生组织限制可以强烈影响初级生产力和碳动态的格局和对环境变化的反应。 这项建议测试的假设群落和生态系统的后果，地下分生组织在草原。 具体的目标是测试的假设，1）芽库密度不同降水梯度，2）分生组织限制约束生产力的响应，在干旱半干旱草原，3）芽库和分生组织密度调节草原植物群落的入侵外来物种，和4）火灾，放牧和水分限制调节模式的芽库种群在草原。 地下分生组织种群的密度，动态，组成和生存能力，地上种群，地上净初级生产力的模式，将在3年的时间内测量整个大平原在7个站点，不同的降水量和生产力。 拟议的跨站点活动将包括3个LTER站点，并加强美国中部地区草地研究科学家之间的合作。 这项研究将提供一个更好的预测了解草原生态系统如何应对全球气候变化，外来物种的入侵，不断变化的土地管理（火灾和放牧制度）。

Studies of plant populations are critical for linking organism traits to ecosystem function, and for understanding ecosystem response to climate change and patterns of biodiversity. In perennial grasslands and other plant communities, the belowground population of meristems (the bud bank) plays a fundamental role in local plant population persistence and dynamics, and may also determine community diversity, stability and invasibility. At the ecosystem level, bud banks and meristem limitation can strongly influence patterns of primary productivity and carbon dynamics and responses to environmental change. This proposal tests hypotheses about the community and ecosystem consequences of belowground meristems in grasslands. The specific objectives are to test the hypotheses that 1) bud bank densities vary across precipitation gradients, 2) meristem limitation constrains productivity responses in arid to semi-arid grasslands, 3) bud banks and meristem density regulate the invasibility of grassland plant communities to exotics, and 4) fire, grazing, and water limitation regulate the patterns of bud bank populations in grasslands. The densities, dynamics, composition and viability of belowground meristem populations, aboveground populations, and patterns of aboveground net primary productivity, will be measured over a 3-yr period across the Great Plains in 7 sites that vary in precipitation and productivity. The proposed cross-site activities will include 3 LTER sites and enhance collaboration among grassland-based research scientists within the central U.S. region. This research will provide a better predictive understanding of how grassland ecosystems respond to global climate change, invasion of exotic species, changing land management (fire and grazing regimes).