The study looked at how the number of different species in an area affects the size of their ranges. They found that in most cases, areas with more species tend to have smaller ranges for each species. This relationship was consistent across different types of plants and animals, as well as in various regions around the world. The researchers suggest that high species diversity can lead to more competition between species, which limits the size of their ranges. This finding has important implications for understanding how species interact with each other and for conservation efforts.