Comparisons of Late Ordovician ecosystem dynamics before and after the Richmondian invasion reveal consequences of invasive species in benthic marine paleocommunities
Comparisons of Late Ordovician ecosystem dynamics before and after the Richmondian invasion reveal consequences of invasive species in benthic marine paleocommunities
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DOI：
10.1017/pab.2020.26
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发表时间：
2020-08-01
期刊：
影响因子：
2.7
通讯作者：
Roopnarine, Peter D.
中科院分区：
文献类型：
--
作者：
Kempf, Hannah L.;Castro, Ian O.;Roopnarine, Peter D.
深入了解社区如何应对极端变化，如生物入侵，对于管理当今的生态系统至关重要。在这里，我们构建了化石食物网，以确定在晚奥陶世（Katian）浅海古群落结构和功能的变化之前和之后的Richmondian入侵，一个有据可查的古代入侵。食物网比较使用描述性指标和级联灭绝的图形模型。当仅使用古生物学数据库相对于博物馆藏品的数据时，在中间营养水平的丰富度被低估，导致模拟古群落稳定性的虚假下降。因此，博物馆收藏和现场采样可能会提供更可靠的数据来源相比，在线数据库的营养组织重建。入侵导致了生态系统动态的一些变化。尽管前和入侵后的食物网之间的拓扑相似性，物种的损失发生相应的功能群的轻微减少。入侵者占领了所有入侵前的功能性行会，除了四个失去的现任行会和一个新行会，证实了入侵者取代现任行会并填补先前存在的利基空间的概念。总体而言，模型表现出较强的抵抗次生灭绝，虽然postinvasion社区有一个较低的阈值崩溃和更多的变量响应扰动。我们将这些动态变化解释为稳定性的降低，尽管整体结构相似。入侵造成的食物网结构和功能的变化表明，如果更多样化的生态系统本身并不更稳定，保护工作可能需要侧重于保护功能多样性。
A thorough understanding of how communities respond to extreme changes, such as biotic invasions, is essential to manage ecosystems today. Here we constructed fossil food webs to identify changes in Late Ordovician (Katian) shallow-marine paleocommunity structure and functioning before and after the Richmondian invasion, a well-documented ancient invasion. Food webs were compared using descriptive metrics and cascading extinction on graphs models. Richness at intermediate trophic levels was underrepresented when using only data from the Paleobiology Database relative to museum collections, resulting in a spurious decrease in modeled paleocommunity stability. Therefore, museum collections and field sampling may provide more reliable sources of data for the reconstruction of trophic organization in comparison to online data repositories. The invasion resulted in several changes in ecosystem dynamics. Despite topological similarities between pre- and postinvasion food webs, species loss occurred corresponding to a minor decrease in functional groups. Invaders occupied all of the preinvasion functional guilds, with the exception of four incumbent guilds that were lost and one new guild, corroborating the notion that invaders replace incumbents and fill preexisting niche space. Overall, models exhibited strong resistance to secondary extinction, although the postinvasion community had a lower threshold of collapse and more variable response to perturbation. We interpret these changes in dynamics as a decrease in stability, despite similarities in overall structure. Changes in food web structure and functioning resulting from the invasion suggest that conservation efforts may need to focus on preserving functional diversity if more diverse ecosystems are not inherently more stable.