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Gamma diversity is defined as the entire species diversity of a landscape or region. Assuming we have a region of 100 square miles of temperate deciduous forest inhabited by cretaceous fauna. How many different species of large herbivores and predators could the region support?

Edit: To narrow things down animal life wise, assume this is in an area inhabited by animal life like that found in the Hell Creek formation.

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  • $\begingroup$ During Cretaceous the average Earth temperature was 7 C higher than today. I suspect there was no temperate deciduous forest. $\endgroup$ – L.Dutch Aug 15 at 6:29
  • $\begingroup$ Also, Cretaceous lasted 80 million years. A narrower time span, maybe? $\endgroup$ – L.Dutch Aug 15 at 6:32
  • $\begingroup$ @L.Dutch - There were temperate forests in more northern latitudes, this Cretaceous climate map also shows various "warm temperate" and "cool temperate" zones, and this abstract says subtropical temps in North America only south of 40 degrees latitude so Hell Creek in Montana should be temperate. Also see this article on temps in Eastern Canada, avg. 68 F in summer. $\endgroup$ – Hypnosifl Aug 15 at 8:21
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    $\begingroup$ Such a small area probably can't support any species of large herbivores and their predators - it's too small to be any single large species' sole habitat. Without a larger range, the area would support too few individuals, leaving the species at risk of extinction. If these large animals can come and go, the answer is 'As many species as can get there and leave again '. $\endgroup$ – Monty Wild Aug 15 at 22:23
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10x10 miles area is very small! You hardly have 2-3 large herbivores and 1-2 large predators species even for morden animals (like boars, elks, deers, wolfs, some big cats). As for hyper large dinosaurs - it more likely to have single species for both (or have herbivores only, like mamonths on Wrangel Island (~8 000 square kilometers - more than ten times more then your hideout).

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  • $\begingroup$ Indeed. North America is round-about 24.7 million square km. And it once supported about 30 million buffalo. It's hard to estimate the fraction of the area that actually supported them. They can't live on lakes or too steep a mountain or desert or such. But the average buffalo-per-square-km is probably less than 10. So 10x10 miles is about 250 sq km, could probably support no more than 2500 buffalo. It's not a huge herd. $\endgroup$ – puppetsock Aug 15 at 14:32

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