An anthropology doctoral student at the University of Cambridge has analyzed centuries of naturalist data to prove a longstanding theory from Charles Darwin’s work. The crux of the work is in the relationship between how species evolve into subspecies and whether that presages new species.

Laura van Holstein said in a statement that the way subspecies emerge depends on whether the species is by land, by air, or by sea. “Subspecies form, diversify and increase in number in a different way in non-terrestrial and terrestrial habitats, and this, in turn, affects how subspecies may eventually become species,” she said.

Darwin was working from his own observations and studies, but van Holstein has synthesized centuries of previous naturalist data into one cohesive explanation that she says proves Darwin’s theories. Civilians have long wondered if the way humans have collapsed many species’ habitats is causing differences in evolution—whether shortening the time frame that species evolve with new mutations or branching different groups into new species more quickly.

This research says that’s likely the case, and suggests environmental activists trying to protect habitat or slow climate change can choose where to focus based on how species are being affected most. Holstein said subspecies tend to be ignored in conservation plans, but her research suggests they play a “pivotal role in long term future evolution dynamics.” The intricacies of Holstein’s analysis are too vast for this Optimist Daily story, but you can check out the full piece here.