You're taking at face value the conservative websites you read that say "only" 800 species have disappeared according to the IUCN. They neglect to mention, deliberately or negligently, that the IUCN only considers a species extinct if it has not been sighted in the last 50 years. Guess when most of the environmental degradation has occurred. What else are those websites leaving out when you read their arguments?

I work in the Bay Area too and am one of those legal specialists you're talking about. I sure wish I had the power you say I did, because development then would be occurring in a very different manner - in the cities instead of spreading out around the countryside.

Just look at our region - half of the pre-development San Francisco Bay/Delta is filled, 80-90% of the biomass in the Bay is low-diversity non-native species, almost all the flatland and much of the hillsides are completely altered from the original habitat and species composition. And we've done better than southern California has at preserving habitat. I think biodiversity losss is a pretty obvious problem.