He forecasts a world dominated by the equivalents of rats and starlings, crows, buffel grass and kudzu, with species dependent on stable wild ecosystems increasingly displaced. Quammen's article is relatively optimistic. Annoying and pestiferous as starlings and tumbleweeds may be, such species will generally respect the boundary of our skin, the occasional rat bite or star thistle prick notwithstanding. Chimps' habitat is shrinking, and wild bands increasingly come into proximity with human beings. The subsequent human death toll may have passed 12 million as you read this.
Microorganisms rule the world, as they have since life began.
The majority of biomass on the planet consists of single-celled organisms. We may notice their presence only when they make us sick or leaven our bread, but we could not live without them. It's a safe bet that there is no animal that could survive without its internal flora of microorganisms. Every moth, wildebeest, or aardvark bears a specialized community of germs, some of them so fitted to their host species that they are found nowhere else. When these animals vanish, their internal flora either find new hosts or go extinct.