Ethics, Morality, Vegetarianism and Carnivorism

I am unsure how to relate this to our environmental concept of the natural hierarchy in communities of ecosystems. In a freshwater ecosystem, examples of the Producers are plants & phytoplankton, Primary Consumers are zooplankton, Secondary Consumers are smaller fish, and Tertiary Consumers are turtles and bigger fish. On land, examples of Producers are trees and plants, Primary Consumers are rabbits, Secondary Consumers are fox, and Tertiary Consumers are coyotes.

We are taught that food chains rarely have more than four trophic levels.
1st Trophic Level are Producers (plants)
2nd Trophic Level are Primary Consumers (herbivores)
3rd Trophic Level are Secondary Consumers (carnivores)
4th Trophic Level are Tertiary Consumers (top carnivores)

So is there a natural selection creating a hierarchy of value in a natural ecosystem? If so, do we have greater moral responsibility to Consumers over Producers? Even greater moral responsibility to the Secondary Consumers than the Primary Consumers? And the greatest moral responsibility to Tertiary Consumers?

If this holds true, and we were to follow this natural evolutionary pattern, then would meat-eating humans and top carnivores have greater value than vegetarian humans and other primary consumers?

I find this to be quite an ethical dilemma. I have always believed in honoring the evolutionary patterns we find in the natural world (as it would exist untainted by human-created destructive patterns). A conundrum I have yet to integrate satisfactorily into my consciousness. Any suggestions?