What a strange question. As a starter I’d like to see us help trees, coral, other primates and megafauna as much as possible. The former because they support so much other biodiversity and the latter because they’re nice to have in the world. Generally speaking though I favor sustainability where that means continuing to improve the quality of life for humans, especially those at the bottom of the socio-economic ladder, whilst trying to minimize the number of other species we drive to extinction. Again, nuance is key here - I don’t think my inability to enumerate every species worthy of help means that we should just dismiss the effort to help other species.

I don't ask you to "enumerate every species worthy of help" but rather to formulate a criteria you use to figure out who is worthy of help and who is not.

The "nice to have in the world" sounds quite arbitrary to me. I don't think the question I ask is strange, I'm trying to figure out the idea you believe in. So far you assume we share some core belief on the topic and the rest is obvious, which I don't think is the case.

OK, I apologize if I misunderstood. My core belief is that it’s possible for humans to continue to prosper without causing a mass extinction of other species. I believe that largely happens through managing our impacts on the environment in which the species live and not just through direct intervention in the lives of those species, e.g. reducing deforestation and rewilding, reducing ocean acidification to save coral reefs. So I don’t think we have to choose specific species we wish to save and those we are willing to let go extinct.