Here are a couple of results from within surveys (not focused on wild animal issues) that suggest that people assign more moral value to non-sentient environmental systems and biodiversity than they do sentient individuals. I think that, intuitively, we all know that people do this, but this social science research provides further evidence:
1) A paper on “Moral Expansiveness: Examining Variability in the Extension of the Moral World” asked participants to rate 30 different entities by the “moral standing” that they deserved. “Low-sentience animals” (chickens, fish, and bees) were deemed by participants to deserve lower moral standing than non-sentient “environmental targets.” These groups had mean scores of 2.64 and 3.53 respectively on a scale from 0 to 9. By comparison, plants had a mean score of 2.52, stigmatised groups of humans (homosexuals, mentally challenged individuals, and refugees) had 5.35 and family/friends had 8.90.
2) A talk by Stefan Schubert on the psychology of existential risk and long-termism refers to a survey which found that a clear majority of respondents were more concerned about the loss of individual human lives than the difference between most dying and all dying (i.e., they weren’t too worried about extinction). But this was reversed when the same question was asked about zebras.