> However, the food chain for homo sapiens largely relies on artificial monocultures that can be moved around and replaced
As just one example, ocean acidification could kill a lot of the algae. Pretty much everything is upstream of algae. It would be catastrophic, even for us.
>>naaski+(OP)
Are cereals, tubers and legumes upstream of algae? They are "pretty much everything* as far as food security is concerned, they constitute 90% of calories consumed by humanity; the three main species - rice, maize, and wheat - currently form 2/3 and in case of a catastrophe probably could cover nearly 100%.