There was a study done. I’m not sure exactly the study, but it’s from a book called Natures Ghosts. It talks about a Roman farm from around 0AD. The farm plot was clear cut, while the forest around it was never touched, including up to this day. The scientists cataloged the plant and animal species from both the farm plot and the untouched forest. Even though the farm plot had massive trees, and hasn’t been disturbed for 2000 years, the difference in species was massive. On the ancient farm plot: many parasitic species/invasive, off the plot: more prominence of delicate or unique species; just a few hundred meters apart. This is what “different forest” is.
The study describes it like this, which sounds like it's the opposite:
> Plant species richness strongly increases toward the center of the settlements, and the frequency of neutrophilous and nitrogen-demanding species is higher.
When I hear things like "delicate or unique species" I get the feeling it's not a particularly scientific conclusion.
So if you read the book: this is from a chapter talking about humans introducing phosphorus fertilizers to the soil has long term impacts on the types of species living in an area. Generally moving in the direction of more aggressive plants that can take advantage of the phosphorus. Many endemic species can’t, therefore are crowded out by faster growing species. The key phrase from your quote is: “neutrophilous and nitrogen-demanding species”. The phosphorus helps in the nitrogen fixation.
Edit: found the study https://pubmed.ncbi.nlm.nih.gov/17601136/