Modern views on the diversity, functional disparity, and structure of Cambrian ecosystems

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• Karma Nanglu, Harvard University
• Tuesday 28 February 2023, 13:00-14:00
• Part II Lecture Theatre and online via Zoom - contact organiser for details.

If you have a question about this talk, please contact Stephen Pates.

This talk is hybrid - email the organisers for a Zoom link

The Cambrian Explosion is one of the most significant biotic events in the history of the Earth. During this time, the complexity of interactions between animals as well as with their environments increased rapidly, in turn leading to more complex community structures. Thus, a clear picture of the structure of Cambrian animal communities is integral to understanding the origins of modern ecosystems. However, relatively few Cambrian fossil sites preserve the total animal community, including the most soft-bodied taxa. Additionally, datasets with high stratigraphic resolution, which are necessary to understand fine scale spatiotemporal gradients, are rare. As a result, fundamental aspects of Cambrian community ecology, such as trophic structure and spatial diversity gradients, remain cryptic. In this seminar, I will present recent work delving into the community ecology of Cambrian marine ecosystems through the lens of some of the best preserved fossil sites in the world. First among these is the celebrated Burgess Shale, located in the Canadian Rocky Mountains. For over 100 years, this site has provided unparalleled insights into early animal evolution, but community-scale analyses have been relatively rare. My data shows that the animal communities of the Burgess Shale were highly variable in terms of total diversity, as well as the most abundant ecological modes represented. Further, even localities within the same geological formation have highly distinct fauna, with several indicator species suggesting a degree of species endemism. Broadly, this suggests that some of the earliest complex animal communities were highly variable both spatially and temporally. I then expand the scope of this study to include older Cambrian communities from China, and re-analyze this enlarged dataset through the lens of functional diversity. One of the major results of these analyses is the observation that alpha diversity and functional diversity fluctuate independently of each other, suggesting that typical metrics of biodiversity alone cannot adequately describe the structure of Cambrian communities. Moving forward, integrating more rigorously sampled datasets with time series information and functional traits is necessary to fully understand the ecological dynamics of the earliest complex ecosystems. Further, expanding the temporal scope of this work, particularly to Ediacaran community datasets, is necessary for a more complete understanding of how early animal ecosystems developed.

This talk is part of the Behaviour, Ecology & Evolution Seminar Series series.

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