Here is an interesting claim: “The 25 million years of large herbivore absence slowed down the evolution of new plant species.”
Defensive features such as spines regressed and fruit sizes increased. The research has demonstrated this using palm trees as a model system…
With their work, the researchers shed new light on evolution and adaptation during one of the most enigmatic and unique periods in the history of plant evolution, during and after megaherbivore extinctions. Understanding how megaherbivore extinctions affected plant evolution in the past can also help predict future ecological developments. For example, the authors have noted the loss of traits during the megaherbivore gap. This loss can affect important ecosystem functions and processes, such as seed dispersal or herbivory. The ongoing extinction of large animals due to human hunting and climate change may thus also affect trait variation in plant communities and ecosystems today and in the foreseeable future.German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, “Dinosaur extinction changed plant evolution” at ScienceDaily (May 2, 2022)
It’s a reasonable idea compared to much that we hear.
The paper is open access.