The oldest evidence of motile complex benthic multicellular organisms is found in Ediacaran aged rocks. At Nilpena Ediacara National Park (NENP), South Australia, one of the most iconic of such organisms, are found in abundance, with over 500 individuals preserved across the site's 33 in situ, fossiliferous beds. These beds vary in mat type and maturity, community diversity and population size. Here, we investigate six beds using spatial point pattern analysis (SPPA) to compare spatial distributions between populations. Five populations were best-fit to a completely spatially random pattern, with a single outlier (TC-MM3) exhibiting signs of environmental heterogeneity. When distributions were examined in relation to other taxa, no indication of spatial competition was detected. Univariate and bivariate spatial distributions imply that was generally not impacted by competition with other taxa, meter-scale environmental heterogeneity, or other external factors. These patterns hold when analyses were split between populations of large and small individuals, and these two size cohorts had no measurable effect on each other's spatial distributions. Additionally, we find no indication of intraspecific competition for or any change in the preferred resources or habitats with growth. These results suggest that the anactualistic environmental conditions produced by ubiquitous organic mats present across Ediacaran seafloors at NENP provided such abundant nutrients that did not have to compete for resources at the meter scale. These results further inform community-scale dynamics of Earth's earliest complex ecosystem.

中文翻译：

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现在来看看完全随机的东西：埃迪卡拉海底狄更逊水母的空间分布


能运动的复杂底栖多细胞生物的最古老证据是在埃迪卡拉纪岩石中发现的。在南澳大利亚州的尼尔皮纳埃迪卡拉国家公园 (NENP)，此类生物是最具标志性的生物之一，在该公园的 33 个原位化石层中发现了丰富的此类生物，其中保存了 500 多个个体。这些床的垫层类型和成熟度、群落多样性和种群规模各不相同。在这里，我们使用空间点模式分析（SPPA）调查了六个床位，以比较种群之间的空间分布。五个群体最适合完全空间随机模式，其中一个异常值（TC-MM3）表现出环境异质性的迹象。当检查与其他类群相关的分布时，没有检测到空间竞争的迹象。单变量和双变量空间分布意味着通常不受与其他类群的竞争、米级环境异质性或其他外部因素的影响。当对大个体和小个体的群体进行分析时，这些模式成立，并且这两个规模的群体对彼此的空间分布没有可测量的影响。此外，我们没有发现任何迹象表明种内竞争或首选资源或栖息地随着生长而发生任何变化。这些结果表明，NENP 埃迪卡拉系海底普遍存在的有机垫所产生的现实环境条件提供了如此丰富的营养物质，无需在米尺度上争夺资源。这些结果进一步揭示了地球最早的复杂生态系统的群落规模动态。