Potential mechanisms of coexistence in closely related forbs

The stable coexistence of very similar species has perplexed ecologists for decades and has been central to the development of coexistence theory. According to modern coexistence theory, species can coexist stably (i.e. persist indefinitely with no long-term density trends) as long as species' niche differences exceed competitive ability differences, even if these differences are very small. Recent studies have directly quantified niche and competitive ability differences in experimental communities at small spatial scales, but provide limited information about stable coexistence across spatial scales in heterogeneous natural communities. In this study, we use experimental and observational approaches to explore evidence for niche and competitive ability differences between two closely related, ecologically similar and widely coexisting annual forbs: Trachymene cyanopetala and T. ornata. We experimentally tested for stabilizing niche differences and competitive ability differences betwe...数十年来，近缘物种的稳定共存始终是生态学界的难解谜题，同时也是共存理论发展的核心议题。根据现代共存理论，只要物种的生态位（niche）差异大于竞争能力差异，即便二者差异极小，物种即可实现稳定共存——即实现种群密度无长期趋势的永久存续。现有研究已在小空间尺度的实验群落中直接量化了生态位与竞争能力差异，但针对异质性自然群落中跨空间尺度的稳定共存现象，相关研究仍较为匮乏。本研究采用实验与观测相结合的方法，针对两种亲缘关系密切、生态特征相似且广泛共存的一年生杂类草本（forbs）——蓝瓣床花（Trachymene cyanopetala）与饰纹床花（T. ornata）之间的生态位差异与竞争能力差异展开证据探索。本研究通过实验检验了二者之间的稳定生态位差异与竞争能力差异，相关论述暂未完成。