Strotz Luke C, Lieberman Bruce S
State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life & Environments and Department of Geology, Northwest University, Xi'an 710069, People's Republic of China.
Biodiversity Institute and Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA.
R Soc Open Sci. 2023 Feb 22;10(2):221210. doi: 10.1098/rsos.221210. eCollection 2023 Feb.
Identifying competitive exclusion at the macroevolutionary scale has typically relied on demonstrating a reciprocal, contradictory response by two co-occurring, functionally similar clades. Finding definitive examples of such a response in fossil time series has proven challenging, however, as has controlling for the effects of a changing physical environment. We take a novel approach to this issue by quantifying variation in trait values that capture almost the entirety of function for steam locomotives (SL), a known example of competitive exclusion from material culture, with the goal of identifying patterns suitable for assessing clade replacement in the fossil record. Our analyses find evidence of an immediate, directional response to the first appearance of a direct competitor, with subsequent competitors further reducing the realized niche of SLs, until extinction was the inevitable outcome. These results demonstrate when interspecific competition should lead to extinction and suggest that clade replacement may only occur when niche overlap between an incumbent and its competitors is near absolute and where the incumbent is incapable of transitioning to a new adaptive zone. Our findings provide the basis for a new approach to analyse putative examples of competitive exclusion that is largely free of assumptions.
在宏观进化尺度上识别竞争排斥通常依赖于证明两个同时出现、功能相似的进化枝的相互矛盾的反应。然而，在化石时间序列中找到这种反应的确切例子已被证明具有挑战性，控制不断变化的物理环境的影响也是如此。我们采用一种新颖的方法来解决这个问题，即量化性状值的变化，这些性状值几乎涵盖了蒸汽机车（SL）的全部功能，蒸汽机车是物质文化中竞争排斥的一个已知例子，目的是识别适合评估化石记录中进化枝替代的模式。我们的分析发现了对直接竞争对手首次出现的即时、定向反应的证据，随后的竞争对手进一步缩小了蒸汽机车的实际生态位，直到灭绝成为不可避免的结果。这些结果表明种间竞争何时会导致灭绝，并表明进化枝替代可能只发生在现存物种与其竞争对手之间的生态位重叠接近绝对且现存物种无法过渡到新的适应区的情况下。我们的发现为一种新的方法提供了基础，该方法用于分析竞争排斥的假定例子，且基本没有假设。
