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Re: New refs (medium)



<<Farlow's chaper in Thomas and Olson, 1990 (eds.) goes into this discussion 
quite thouroughly, and though dated, no one has yet offered how a sauropod can 
be reasonably sustained by an ecosystem apart from constant migration (and 
perhaps leading to why sauropods make bad mothers, they'd kill the environment 
just after a few weeks, not to mention a herd of these).>>

     I agree that no one has published an explicit rebuttle to Farlow's chpter, 
but I think the literature is sprinkled with evidence for why Farlow is wrong.  
First of all, population ecology provides explanations for why sauropods will 
not get too numerous.  Environments have a carrying capacity that animal 
populations cannot exceed (for long).  If sauropods were low RMR ectotherms, 
there would simply be more of them (a point made by R. McNeil Alexander in his 
book).  It is possible to lower the carrying capacity of an area by 
over-wxploiting its resources, but generally only happens when population 
dispersal is not possible (e.g. islands, or environments fragmented by human 
land use)  The real question is whether sauropod genetics could have been 
sustained.  This makes Greg Paul's observations on dinosaur reproduction even 
more pertinent.  The high fecundity of even the largest dinosaurs (compared to 
large mammals) could have allowed them to maintain populations with fewe!
r adult animals.  The only proble then becomes maintaining genetic diversity.  
Low population densities don't usually get in the way of genetic diversity in 
large land animals though, since they can move larger distances in search of a 
mate (also, it's worth pointing out that inbreeding is generally only a grave 
threat to the genetic diversity of small populations, like the black-footed 
ferret).
     I really don't see any ecological reason why endothermic sauropods should 
have been impossible, though I'm sure they would be hard on a habitat, just as 
elephant herds are today.
     One last thing, I'm not aware of any really compelling evidence for really 
large herds of sauropods.  I know of trackways of small herds, and multiple 
skeletal associations, but nothing like those known for certaopsians and 
hadrosaurs.  Lockley has described some "highways" of sauropod tracks, but they 
likely represent accumulations of lots of independat herds/individuals crossing 
at different times.  Does anyone else know of a good example of a really large 
sauropod herd?

Scott