Thanks for the reference to the Encyclopedia of Dinosaurs samples! I've been doing some browsing, on herbivory:
<The dominant herbivorous dinosaurs [from inception to mid-Cretaceous] found in association with the lower latitude communities were the giant, high-feeding sauropods, although smaller forms were also present. One hypothesis is that the generally large stature and posited low food quality of the available gymnosperms influenced the size and morphology of the herbivores, as the lower quality food necessitated the consumption of larger quantities of food, and its retention for longer times.>
(Tiffney, Dinosaurs and Plants)
If the limitation on neck movement is correct, then 'high-feeding' is unlikely, unless rearing proves reasonable. If the food is low quality and the available supply is less than previously assumed when high-feeding was thought likely, is this hypothesis more questionable?
<However, other factors may also have entered into the equation, including the digestive physiology of large
dinosaurs. It has also been suggested that the large sauropods fed on "fern prairies", which would have provided a higher-quality and more disturbance-tolerant food source.>
Does the prairie in "fern prairie" mean the sort of buffalo herd prairie I'm visualizing? If so, wouldn't height be a disadvantage? Also, the entry observes that:
< Most of the Mesozoic was dominated by large, disturbance-creating, herbivores that were predators upon whole plants and which operated in an open environment.>
Assuming the comparatively low reproduction rates for gymnosperms and the fact that large sauropods were eating them, how long would such prairies last?
Also, these prairies would be found in the areas dominated by large sauropods, areas described as 'more drought-adapted [, hotter,] and probably more open', compared to '[h]igher paleolatitude communities [, which] may have been cooler and wetter, and thus possibly more productive.' Why wouldn't the prairies be found at higher latitudes instead?
As you can see, I've been wondering whether a reduction in the amount of food available to at least some sauropods because of limited neck movement might affect their ability to survive. The information in this entry doesn't resolve the issue for me.
I'm also thinking about the idea that a large animal in warm, open terrain does not have to generate much internal heat.
Maybe you could watch a sauropod for a long time from the same spot...
Anyone care to comment?