The main aim of this project is to identify the ways in which dinosaurian megaherbivores were possibly integrated to form stable, operational communities and influenced the functioning of their ecosystems, and how this changed over time.

 

 

We will build a comprehensive database for terrestrial vertebrate communities

of dinosaur-dominated ecosystems across the Kimmeridgian (157.3–152.1 Ma)

and Campanian (83.6–72.1 Ma) time intervals of the North American Morrison

and Dinosaur Park formations, respectively. Sauropods (long-necked species

like Brontosaurus and Diplodocus) were particularly ascendant during the

Jurassic Period (201–145 Ma), with some of their most famous fossils coming

from North America. Following the extinction event at the Jurassic–Cretaceous

boundary, ornithischians (e.g., duck-billed hadrosauroids, horned ceratopsians,

armoured ankylosaurs) became the most conspicuous dinosaurian herbivores

until the asteroid impact 66 Ma ago. However, the ecological consequences

of this large-scale turnover for Mesozoic ecosystems are still largely unexplored.

 

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Using a novel combination of Markov networks, Earth System models, and community resemblance measurements based on body size variation, we will address the more specific, key hypotheses:

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    1/ Megaherbivores had disproportionately larger effects on community dynamics and ecosystem functioning than their   smaller saurian and mammalian counterparts.

     2/ This was true for all megaherbivorous clades, although some diversity in their impacts on the ways in which species assemble and interact is expected between sauropod-dominated vs. ornithischian-dominated faunas.

     3/ Their effects on community dynamics varied along ecological gradients (proxies of palaeoclimates and land surfaces).

     4/ Extrinsic environmental factors and intrinsic functional features selected for clear distinct patterns of community organisation in terms of body size structure.

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