Complex sentence: Many wildlife species have the potential of becoming a "nuisance" species, and whether or not a species is regarded as a pest can be directly correlated with the degree to which that animal can be tolerated by humans.
Split into simpler sentences: Many wildlife species have the potential of becoming a "nuisance" species. Whether or not a species becomes a pest can be directly correlated to the degree at which that animal can be tolerated by humans.